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

Abstract

To provide an electrostatic charge image development toner which is less likely to slip through.SOLUTION: An electrostatic charge image development toner provided herein comprises toner particles containing a binder resin, mold release agent, photoluminescent dye, and aminocarboxylic acid compound.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a toner for electrostatic charge image development, an electrostatic charge image developer, a toner cartridge, a process cartridge, and an image forming apparatus.

Background Art

[0002] Patent Document 1 discloses a method for manufacturing a low-gloss toner, the method including: forming an emulsion by mixing a resin, a colorant, and an optional wax in water; heating the emulsion in the presence of a polyion coagulant to form a plurality of aggregated particles composed of a resin, a colorant, a charge control agent, and an optional wax, wherein the heating is up to a temperature below the glass transition temperature of the resin; adding trisodium citrate dihydrate in an amount of 0.4% by weight to about 1.0% by weight based on the total weight of the reagents to the heated emulsion while stirring; heating the aggregated particles to a temperature above the glass transition temperature of the resin to form toner particles having a volume average particle diameter of 4.3 micrometers to 4.9 micrometers; separating the toner particles from the water; and drying the particles.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When an image is formed using a toner containing a glitter pigment, when cleaning the toner remaining after transfer with a cleaning blade, the glitter pigment in the toner particles may pierce the cleaning blade, resulting in blade chipping. When blade chipping occurs, toner may slip through the chipped part of the blade, resulting in color streaks caused by toner slippage.

[0005] The present invention aims to provide an electrostatic charge image developing toner in which toner penetration is suppressed as compared with the case where toner particles are composed of a binder resin, a release agent, and a bright pigment.

Means for Solving the Problems

[0006] Specific means for solving the above problems include the following aspects.

[0007] <1> A binder resin, A release agent, A bright pigment, An aminocarboxylic acid compound, An electrostatic charge image developing toner containing toner particles containing the above.

[0008] <2> The number of carboxy groups of the aminocarboxylic acid compound is 3 or more and 5 or less, and the number of amino groups of the aminocarboxylic acid compound is 2 or more and 4 or less. The electrostatic charge image developing toner according to <1>. <3> The number of carboxy groups of the aminocarboxylic acid compound is 4 or more and 5 or less. The electrostatic charge image developing toner according to <2>. <4> The number of amino groups of the aminocarboxylic acid compound is 2 or more and 3 or less. The electrostatic charge image developing toner according to <2> or <3>.

[0009] <5> The content of the aminocarboxylic acid compound is 1 ppm or more and 100 ppm or less with respect to the whole electrostatic charge image developing toner. The electrostatic charge image developing toner according to any one of <1> to <4>. <6> The content of the aminocarboxylic acid compound is 30 ppm or more and 60 ppm or less with respect to the whole electrostatic charge image developing toner. The electrostatic charge image developing toner according to <5>.

[0010] <7> The pH of the aminocarboxylic acid compound is 4 or more and 12 or less. The toner for electrostatic charge image development according to any one of <1> to <6>. <8> The pH of the aminocarboxylic acid compound is 5 or more and 8 or less. The toner for electrostatic charge image development according to <7>.

[0011] <9> The ratio C / D of the average maximum thickness C to the average circle equivalent diameter D of the toner particles is 0.01 or more and 0.50 or less. The toner for electrostatic charge image development according to any one of <1> to <8>. <10> The binder resin contains a polyester resin. The toner for electrostatic charge image development according to any one of <1> to <9>.

[0012] <11> An electrostatic charge image developer containing the toner for electrostatic charge image development according to any one of <1> to <10>. <12> Accommodating the toner for electrostatic charge image development according to any one of <1> to <10>, A toner cartridge that is detachable from an image forming apparatus. <13> Accommodating the electrostatic charge image developer according to <11>, and having developing means for developing an electrostatic charge image formed on the surface of an image carrier as a toner image with the electrostatic charge image developer. A process cartridge that is detachable from an image forming apparatus. <14> An image carrier, Charging means for charging the surface of the image carrier, Electrostatic charge image forming means for forming an electrostatic charge image on the charged surface of the image carrier, Accommodating the electrostatic charge image developer according to <11>, and having developing means for developing an electrostatic charge image formed on the surface of the image carrier as a toner image with the electrostatic charge image developer. An intermediate transfer body onto which the toner image is transferred on the surface, Primary transfer means for primarily transferring the toner image formed on the surface of the image carrier to the surface of the intermediate transfer body, Secondary transfer means for secondarily transferring the toner image transferred onto the surface of the intermediate transfer body onto the surface of the recording medium; Cleaning means having a cleaning blade for cleaning the surface of the intermediate transfer body; Fixing means for fixing the toner image secondarily transferred onto the surface of the recording medium; An image forming apparatus comprising the same. <15> An image holding body; Charging means for charging the surface of the image holding body; Electrostatic charge image forming means for forming an electrostatic charge image on the charged surface of the image holding body; Developing means for accommodating the electrostatic charge image developer according to <11> and developing the electrostatic charge image formed on the surface of the image holding body as a toner image with the electrostatic charge image developer; Transfer means for transferring the toner image formed on the surface of the image holding body onto the surface of the recording medium; Cleaning means having a cleaning blade for cleaning the surface of the image holding body; Fixing means for fixing the toner image transferred onto the surface of the recording medium; An image forming apparatus comprising the same.

Advantages of the Invention

[0013] According to the invention according to <1>, there is provided an electrostatic charge image developing toner in which toner leakage is suppressed as compared with the case where toner particles are composed of a binder resin, a release agent, and a brightening pigment.

[0014] According to the invention according to <2>, there is provided an electrostatic charge image developing toner in which toner leakage is suppressed as compared with the case where the number of carboxy groups is 2 or less or the number of amino groups is 1 or less. According to the invention according to <3>, there is provided an electrostatic charge image developing toner in which toner leakage is suppressed as compared with the case where the number of carboxy groups is 3 or less. According to the invention according to <4>, there is provided an electrostatic charge image developing toner in which fogging is suppressed as compared with the case where the number of amino groups is 4 or more.

[0015] According to the invention according to <5>, there is provided an electrostatic charge image developing toner in which toner scattering is suppressed as compared with the case where the content of the aminocarboxylic acid compound is less than 1 ppm. According to the invention according to <6>, there is provided an electrostatic charge image developing toner in which toner scattering is suppressed as compared with the case where the content of the aminocarboxylic acid compound is less than 30 ppm.

[0016] According to the invention according to <7>, there is provided an electrostatic charge image developing toner in which toner scattering is suppressed as compared with the case where the pH of the aminocarboxylic acid compound exceeds 12. According to the invention according to <8>, there is provided an electrostatic charge image developing toner in which toner scattering is suppressed as compared with the case where the pH of the aminocarboxylic acid compound exceeds 8.

[0017] According to the invention according to <9>, there is provided an electrostatic charge image developing toner in which fogging is suppressed as compared with the case where the ratio C / D is less than 0.01. According to the invention according to <10>, there is provided an electrostatic charge image developing toner in which toner scattering is suppressed as compared with the case where the binder resin is only a styrene-based resin.

[0018] According to the invention according to <11>, <12>, <13>, <14>, or <15>, there is provided an electrostatic charge image developer, a toner cartridge, a process cartridge, or an image forming apparatus including an electrostatic charge image developing toner in which toner scattering is suppressed as compared with the case where the toner particles are composed of a binder resin, a release agent, and a bright pigment.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]

Figure 1

Figure 2

MODE FOR CARRYING OUT THE INVENTION

[0020] Hereinafter, embodiments which are examples of the present invention will be described. These descriptions and examples are illustrative of the embodiments and do not limit the scope of the invention. In the numerical ranges described stepwise in this specification, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of the numerical range described in other stepwise descriptions. Also, in the numerical ranges described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples.

[0021] Each component may contain a plurality of corresponding substances. When referring to the amount of each component in the composition, when there are a plurality of substances corresponding to each component in the composition, unless otherwise specified, it means the total amount of the plurality of substances present in the composition.

[0022] <Electrostatic charge image developing toner> The electrostatic charge image developing toner according to this embodiment (hereinafter, the electrostatic charge image developing toner is also referred to as "toner") contains toner particles containing a binder resin, a release agent, a bright pigment, and an aminocarboxylic acid compound. In this embodiment, due to the above configuration, toner scattering is suppressed. The reason is not clear, but it is presumed as follows.

[0023] Toner particles containing a bright pigment tend to have a flat shape, and tend to have a shape with irregularities in a region with a high curvature centered on the intersection line between the flat surface direction and the thickness direction. And when the shape of the toner particles is flat, when a transfer voltage is applied, the major axis of the toner particles becomes parallel to the electric field direction, that is, a direction close to perpendicular to the toner image, and this direction is maintained even when remaining after transfer. For example, when the toner image on the intermediate transfer body is secondarily transferred to the recording medium, the long axis of the toner particles becomes a direction close to perpendicular to the surface of the intermediate transfer body by applying a secondary transfer voltage. And after the toner image is secondarily transferred from the intermediate transfer body to the recording medium, the toner particles remaining on the intermediate transfer body also have their long axes in a direction close to perpendicular to the surface of the intermediate transfer body.

[0024] In this state, when passing through the cleaning process, one end in the long axis direction of the remaining toner particles collides with the tip of the cleaning blade (hereinafter also referred to as the "blade end"). And if there are irregularities in the region with a high curvature on the surface of the toner particles, the fluorescent pigment penetrates the binder resin and contacts the blade end, and by piercing, a chip occurs at the blade end, and color streaks may occur due to the toner slipping through.

[0025] On the other hand, in this embodiment, the toner particles contain an aminocarboxylic acid compound. Therefore, the presence of the aminocarboxylic acid compound in the binder resin increases the mechanical strength against instantaneous impact. For example, in toner particles manufactured by the aggregation coalescence method, in the manufacturing process, the aminocarboxylic acid compound is interposed between the resin particles and coalesced in a strongly aggregated state. The reason is not clear, but it is presumed that the carboxy group of the aminocarboxylic acid compound adsorbs to the resin particles, and since the aminocarboxylic acid compound has an amino group and has a structure with a certain angle, even resin particles with a complex three-dimensional structure are strongly aggregated. And particularly, the density of the binder resin in the vicinity of the surface where the aminocarboxylic acid compound is likely to exist is high, and toner particles with high mechanical strength are obtained. Thereby, even when the long axis of the toner particles collides with the blade end in a direction close to perpendicular, the exposure of the fluorescent pigment is suppressed, the chipping of the blade end is suppressed, and it is considered that the slipping through of the toner is also suppressed. And by suppressing the slipping through of the toner, the color streaks caused by the slipping through of the toner are suppressed. For the above reasons, it is presumed that the toner for electrostatic charge image development according to this embodiment suppresses the slipping through of the toner. Note that the "flat shape" refers to a shape that has a flat surface and the equivalent diameter of the projected circle on the flat surface (hereinafter also referred to as the "equivalent circle diameter") is larger than the maximum value of the thickness perpendicular to the flat surface (hereinafter also referred to as the "maximum thickness"). Also, the "flat surface" refers to the surface with the largest projected area.

[0026] Hereinafter, the details of the toner according to this embodiment will be described.

[0027] The toner according to this embodiment is composed of toner particles and, if necessary, an external additive.

[0028] (Toner particles) The toner particles contain at least a binder resin, a release agent, a bright pigment, and an aminocarboxylic acid compound, and may contain, if necessary, a colorant other than the bright pigment, other additives, etc.

[0029] -Binder resin- Examples of the binder resin include homopolymers of monomers such as styrenes (e.g., styrene, parachlorostyrene, α-methylstyrene, etc.), (meth)acrylic acid esters (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.), olefins (e.g., ethylene, propylene, butadiene, etc.), or vinyl resins composed of copolymers obtained by combining two or more of these monomers. Examples of the binder resin include non-vinyl resins such as epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, modified rosin, mixtures of these with the vinyl resins, or graft polymers obtained by polymerizing vinyl monomers in the presence of these. These binder resins may be used alone or in combination of two or more.

[0030] As the binder resin, a polyester resin is preferable. When the binder resin includes a polyester resin, the toner's penetration is more suppressed. The reason is not clear, but it is presumed that the hydrophilic group at the end of the polyester resin is likely to adsorb to the carbonyl group of the aminocarboxylic acid compound, so the cohesiveness between the binder resins is enhanced through the aminocarboxylic acid compound, the density of the binder resin is high near the surface, and the mechanical strength is increased. Examples of the polyester resin include known polyester resins.

[0031] Examples of the polyester resin include condensation polymers of polyvalent carboxylic acids and polyhydric alcohols. Note that as the polyester resin, commercially available products may be used, or those synthesized may be used.

[0032] Examples of the polyvalent carboxylic acid include aliphatic dicarboxylic acids (such as oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, alkenyl succinic acid, adipic acid, sebacic acid, etc.), alicyclic dicarboxylic acids (such as cyclohexanedicarboxylic acid, etc.), aromatic dicarboxylic acids (such as terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, etc.), anhydrides thereof, or lower (for example, having 1 to 5 carbon atoms) alkyl esters thereof. Among these, as the polyvalent carboxylic acid, for example, aromatic dicarboxylic acids are preferable. The polyvalent carboxylic acid may be used in combination with a carboxylic acid having a trivalent or higher valence that forms a crosslinked structure or a branched structure together with the dicarboxylic acid. Examples of the carboxylic acid having a trivalent or higher valence include trimellitic acid, pyromellitic acid, anhydrides thereof, or lower (e.g., having 1 to 5 carbon atoms) alkyl esters thereof, etc. The polyvalent carboxylic acid may be used alone or in combination of two or more.

[0033] Examples of the polyhydric alcohol 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 adduct of bisphenol A, propylene oxide adduct of bisphenol A, etc.). Among these, as the polyhydric alcohol, for example, aromatic diols and alicyclic diols are preferable, and more preferably aromatic diols. The polyhydric alcohol may be used in combination with a polyhydric alcohol having a trivalent or higher valence that forms a crosslinked structure or a branched structure together with the diol. Examples of the polyhydric alcohol having a trivalent or higher valence include glycerin, trimethylolpropane, and pentaerythritol. The polyhydric alcohol may be used alone or in combination of two or more.

[0034] The glass transition temperature (Tg) of the polyester resin is preferably 50°C or higher and 80°C or lower, and more preferably 50°C or higher and 65°C or lower. The glass transition temperature is determined from the DSC curve obtained by differential scanning calorimetry (DSC). More specifically, it is determined by the "extrapolated glass transition start temperature" described in the method for determining the glass transition temperature in JIS K 7121-1987 "Method for Measuring the Transition Temperature of Plastics".

[0035] The weight average molecular weight (Mw) of the polyester resin is preferably 5,000 or more and 1,000,000 or less, more preferably 7,000 or more and 500,000 or less. The number average molecular weight (Mn) of the polyester resin is preferably 2,000 or more and 100,000 or less. The molecular weight distribution Mw / Mn of the polyester resin is preferably 1.5 or more and 100 or less, more preferably 2 or more and 60 or less. The weight average molecular weight and the number average molecular weight are measured by gel permeation chromatography (GPC). The molecular weight measurement by GPC is performed using Tosoh's GPC·HLC-8120GPC as the measuring device, Tosoh's column·TSKgel SuperHM-M (15 cm), and THF solvent. The weight average molecular weight and the number average molecular weight are calculated from this measurement result using a molecular weight calibration curve prepared with a monodisperse polystyrene standard sample.

[0036] The polyester resin is obtained by a well-known production method. Specifically, for example, it can be obtained by a method in which the polymerization temperature is 180°C or more and 230°C or less, the inside of the reaction system is depressurized as necessary, and the reaction is carried out while removing water and alcohol generated during condensation. When the raw material monomer does not dissolve or is not compatible at the reaction temperature, a high-boiling solvent may be added as a dissolution aid to dissolve it. In this case, the polycondensation reaction is carried out while distilling off the dissolution aid. When there are monomers with poor compatibility, it is advisable to condense the monomers with poor compatibility in advance with the acid or alcohol intended for polycondensation and then carry out polycondensation together with the main component.

[0037] As the content of the binder resin, for example, it is preferably 40% by mass or more and 95% by mass or less, more preferably 50% by mass or more and 90% by mass or less, and even more preferably 60% by mass or more and 85% by mass or less with respect to the entire toner particles.

[0038] -Release agent- 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; ester waxes such as fatty acid esters and montanic acid esters; and the like. The release agent is not limited thereto.

[0039] The melting temperature of the release agent is preferably 50°C or higher and 110°C or lower, more preferably 60°C or higher and 100°C or lower. The melting temperature is determined from the DSC curve obtained by differential scanning calorimetry (DSC) according to the "melting peak temperature" described in the method for determining the melting temperature in JIS K 7121-1987 "Method for Measuring the Transition Temperature of Plastics".

[0040] The content of the release agent is preferably 1% by mass or more and 20% by mass or less, more preferably 5% by mass or more and 15% by mass or less, based on the total toner particles.

[0041] -Glitter Pigment- Examples of the glitter pigment include metal pigments such as aluminum, brass, bronze, nickel, stainless steel, and zinc; mica coated with titanium oxide, yellow iron oxide, etc.; flaky crystals or plate-like crystals such as aluminosilicate, basic carbonate, barium sulfate, titanium oxide, and bismuth oxychloride; flaky glass powder and flaky glass powder vapor-deposited with metal; and the like. Among them, metal pigments are desirable from the viewpoint of specular reflection intensity, and flat-shaped metal pigments are more desirable from the viewpoint of higher specular reflection intensity. Among the metal pigments, aluminum pigments are desirable from the viewpoint of easily obtaining flat powder. The surface of the metal pigment may be coated with silica, acrylic resin, polyester resin, or the like.

[0042] The volume average particle diameter of the glitter pigment is preferably 3 μm or more and 20 μm or less, more preferably 4.5 μm or more and 18 μm or less, and particularly preferably 6 μm or more and 16 μm or less.

[0043] The volume average particle diameter of the above-mentioned fluorescent pigment is measured using a Coulter Multisizer II (manufactured by Beckman Coulter, Inc.), and the electrolyte used is ISOTON-II (manufactured by Beckman Coulter, Inc.). When measuring, as a dispersant, 0.5 mg or more and 50 mg or less of the measurement sample is added to 2 ml of a 5 mass% aqueous solution of a surfactant (sodium alkylbenzene sulfonate is preferred). This is added to 100 ml or more and 150 ml or less of the electrolyte. The electrolyte in which the sample is suspended is dispersed by an ultrasonic disperser for 1 minute, and the particle size distribution of particles having a particle diameter in the range of 2 μm or more and 60 μm or less is measured using an aperture having an aperture diameter of 100 μm by a Coulter Multisizer II. The number of particles to be sampled is 50,000. Based on the measured particle size distribution, a cumulative distribution of volume is drawn for the divided particle size ranges (channels) from the smaller diameter side, and the particle diameter at which the cumulative value reaches 50% is defined as the volume average particle diameter D50v. In addition, the volume average particle diameter of the fluorescent pigment in the toner is measured by the above method after removing components other than the fluorescent pigment.

[0044] The content of the fluorescent pigment in the toner particles is preferably 1 part by mass or more and 70 parts by mass or less, and more preferably 5 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the binder resin.

[0045] -Aminocarboxylic acid compound- The aminocarboxylic acid compound is not limited as long as it has an amino group and a carboxy group. Examples of the amino group of the aminocarboxylic acid compound include a primary amino group, a secondary amino group, and a tertiary amino group. The aminocarboxylic acid compound preferably has a tertiary amino group, and more preferably all of the amino groups of the aminocarboxylic acid compound are tertiary amino groups. The number of amino groups in the aminocarboxylic acid compound may be 1 or more, preferably 2 or more, more preferably 2 to 4, even more preferably 2 to 3, and particularly preferably 2. When the number of amino groups in the aminocarboxylic acid compound is within the above range, the toner skipping is suppressed as compared with the case where the number is less than the above range. Further, when the number of amino groups in the aminocarboxylic acid compound is within the above range, there is an advantage that the generation of toner coarse powder due to excessive cohesive force is suppressed as compared with the case where the number is more than the above range.

[0046] The number of carboxy groups in the aminocarboxylic acid compound may be 1 or more, preferably 2 or more, more preferably 3 to 5, even more preferably 4 to 5, and particularly preferably 4. When the number of carboxy groups in the aminocarboxylic acid compound is within the above range, the toner skipping is suppressed as compared with the case where the number is less than the above range. Further, when the number of carboxy groups in the aminocarboxylic acid compound is within the above range, fogging caused by aggregation of toner particles is suppressed as compared with the case where the number is more than the above range.

[0047] The carboxy group of the aminocarboxylic acid compound may form a salt with an alkali metal ion, an alkaline earth metal ion, an organic cation, etc. That is, the aminocarboxylic acid compound may be an aminocarboxylic acid in which the carboxy group does not form a salt, or may be an aminocarboxylic acid salt in which the carboxy group of the aminocarboxylic acid forms a salt, and among them, aminocarboxylic acid salts are preferred. Examples of the aminocarboxylic acid salt include sodium aminocarboxylate, potassium aminocarboxylate, calcium aminocarboxylate, magnesium aminocarboxylate, aluminum aminocarboxylate, ammonium aminocarboxylate, and the like.

[0048] When the aminocarboxylic acid compound has two or more amino groups, examples of the linking group that links two or more amino groups include an alkylene group, a carbonyl group, a divalent or higher linking group formed by combining these, and the like. The number of carbon atoms of the alkylene group that links two or more amino groups is preferably 1 or more and 4 or less, more preferably 1 or more and 2 or less, and even more preferably 2. In addition, examples of the linking group that links an amino group and a carboxy group include an alkylene group, a carbonyl group, a divalent or higher linking group formed by combining these, and the like. The number of carbon atoms of the alkylene group that links an amino group and a carboxy group is preferably 1 or more and 4 or less, more preferably 1 or more and 2 or less, and even more preferably 1. In addition, the aminocarboxylic acid compound may further have other substituents other than the amino group and the carboxy group. Examples of the other substituents include an alkyl group, a hydroxy group, a phenyl group, a monovalent group formed by combining these, and the like.

[0049] Specific examples of the aminocarboxylic acid compound include, for example, ethylenediaminetetraacetic acid (EDTA), hydroxyethylethylenediaminetriacetic acid (HEDTA), diethylenetriaminepentaacetic acid (DTPA), 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayltetraacetic acid (DOTA), L-asparagine monohydrate, triethylenetetraminehexaacetic acid (TTHA), nitrilotriacetic acid (NTA), 3-hydroxy-2,2'-iminodisuccinic acid (HIDS), N-(2,6-dimethylphenylcarbamoylmethyl)iminodiacetic acid, salts thereof, and the like.

[0050] Examples of the molecular weight of the aminocarboxylic acid compound include a range of 100 or more and 1000 or less. From the viewpoint of the cohesive force between the binder resins, a range of 150 or more and 800 or less is preferable, and a range of 200 or more and 500 or less is more preferable.

[0051] The pH of the aminocarboxylic acid compound is, for example, 4 or higher and 12 or lower, preferably 5 or higher and 8 or lower, and more preferably 6 or higher and 7.5 or lower. When the pH of the aminocarboxylic acid compound is within the above range, the above-described effect of the aminocarboxylic acid compound can be more easily obtained and toner leakage is suppressed as compared with the case where the pH is higher than the above range. On the other hand, when the pH of the aminocarboxylic acid compound is within the above range, fogging caused by coarse powder generated due to excessive aggregation force at one time is suppressed as compared with the case where the pH is lower than the above range.

[0052] Here, the pH of the aminocarboxylic acid compound is measured as follows. Specifically, a measurement sample is prepared by dissolving the aminocarboxylic acid compound to be measured in ultrapure water to a concentration of 1%. Then, the pH value obtained by measurement using an arbitrary commercially available pH meter is defined as the pH of the aminocarboxylic acid compound. When measuring the pH of the aminocarboxylic acid compound contained in toner particles, weigh 1 g of toner, add 20 ml of tetrahydrofuran (THF), and perform ultrasonic treatment for 15 min. Then, add 60 ml of acetonitrile, let stand for 60 min, centrifuge at 20000 rpm / 4°C / 30 min, and collect the supernatant. Filter this supernatant through a 0.2 μm filter, add 0.1 ml of octylphenol to obtain a measurement sample. Analyze the obtained measurement sample by liquid chromatography mass spectrometer (LCMS-IT-TOF: manufactured by Shimadzu Corporation). Identify the structure of the aminocarboxylic acid compound contained in the toner from the intensity of the obtained peak and waveform separation. Prepare the aminocarboxylic acid compound clarified by this method by an arbitrary method, prepare a 1% aqueous solution as described above, and define the pH value obtained by measurement using an arbitrary commercially available pH meter as the pH of the aminocarboxylic acid compound.

[0053] The content of the aminocarboxylic acid compound is preferably 1 ppm or more and 100 ppm or less, more preferably 10 ppm or more and 80 ppm or less, and even more preferably 30 ppm or more and 60 ppm or less with respect to the whole toner. When the content of the aminocarboxylic acid compound is within the above range, compared with the case where it is less than the above range, the above-described effect by the aminocarboxylic acid compound is easily obtained, and toner skipping is suppressed. On the other hand, when the content of the aminocarboxylic acid compound is within the above range, compared with the case where it is more than the above range, fogging caused by coarse powder generated by excessive cohesive force at one time is suppressed.

[0054] Here, the content of the aminocarboxylic acid compound contained in the toner is determined by the above-described pH measurement operation. Specifically, 1 g of the toner is weighed, 20 ml of tetrahydrofuran (THF) is added, and ultrasonic treatment is performed for 15 min. Thereafter, 60 ml of acetonitrile is added, and after standing for 60 min, centrifugation is performed under the conditions of 20000 rpm / 4 °C / 30 min, and the supernatant is collected. This supernatant is filtered through a 0.2 μm filter, and 0.1 ml of octylphenol is added to obtain a measurement sample. The obtained measurement sample is analyzed by a liquid chromatography mass spectrometer (LCMS-IT-TOF: manufactured by Shimadzu Corporation). From the intensity of the obtained peak and waveform separation, the structure and content of the aminocarboxylic acid compound contained in the toner are calculated.

[0055] -Colorants other than the bright pigment- Examples of colorants other than the bright pigment include various pigments such as carbon black, chrome yellow, Hansa yellow, benzidine yellow, threne yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, Balkan orange, Watchung red, permanent red, brilliant carmine 3B, brilliant carmine 6B, DuPont oil red, pyrazolone red, resorcinol red, rhodamine B lake, lake red C, pigment red, rose bengal, aniline blue, ultramarine blue, calco oil blue, methylene blue chloride, phthalocyanine blue, pigment blue, phthalocyanine green, malachite green oxalate, etc., or 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, aniline black-based, polymethine-based, triphenylmethane-based, diphenylmethane-based, thiazole-based, etc. Colorants other than the bright pigment may be used alone or in combination of two or more.

[0056] As the colorant other than the bright pigment, a surface-treated colorant may be used as needed, and it may be used in combination with a dispersant. Also, a plurality of types of colorants may be used in combination.

[0057] As the content of the colorant other than the bright pigment, for example, with respect to the entire toner particles, 1% by mass or more and 30% by mass or less is preferable, and 3% by mass or more and 15% by mass or less is more preferable.

[0058] -Other Additives- 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.

[0059] -Properties of Toner Particles, etc.- The toner particles may be single-layer structured toner particles or so-called core-shell structured toner particles composed of a core part (core particles) and a coating layer (shell layer) that coats the core part. Here, the core-shell structured toner particles may preferably be composed of a core part containing, for example, a binder resin, a release agent, a bright pigment, and other additives such as a colorant other than the bright pigment as necessary, and a coating layer containing a binder resin.

[0060] The volume average particle diameter (D50v) of the toner particles is preferably 2 μm or more and 12 μm or less, more preferably 4 μm or more and 11 μm or less.

[0061] In addition, various average particle diameters and various particle size distribution indexes of the toner particles are measured using a Coulter Multisizer II (manufactured by Beckman Coulter), and the electrolyte used is ISOTON-II (manufactured by Beckman Coulter). At the time of measurement, as a dispersant, 0.5 mg or more and 50 mg or less of a measurement sample is added to 2 ml of a 5% aqueous solution of a surfactant (sodium alkylbenzene sulfonate is preferred). This is added to 100 ml or more and 150 ml or less of the electrolyte. The electrolyte in which the sample is suspended is subjected to a dispersion treatment for 1 minute with an ultrasonic disperser, and the particle size distribution of particles having a particle diameter in the range of 2 μm or more and 60 μm or less is measured using an aperture having an aperture diameter of 100 μm with a Coulter Multisizer II. The number of particles to be sampled is 50,000. Based on the measured particle size distribution, a cumulative distribution of volume and number is drawn for each particle size range (channel) divided, and the particle diameter at which the cumulative value becomes 16% is defined as the volume particle diameter D16v, the number particle diameter D16p, the particle diameter at which the cumulative value becomes 50% is defined as the volume average particle diameter D50v, the cumulative number average particle diameter D50p, and the particle diameter at which the cumulative value becomes 84% is defined as the volume particle diameter D84v and the number particle diameter D84p. Using these, the volume particle size distribution index (GSDv) is (D84v / D16v) 1 / 2 , and the number particle size distribution index (GSDp) is (D84p / D16p) 1 / 2 and is calculated as such.

[0062] From the viewpoint of obtaining a highly brilliant image, the toner particles are preferably flat. That is, the toner particles have a flat surface, and the equivalent circular diameter (i.e., "equivalent circle diameter") of the projection circle on the flat surface is preferably larger than the maximum value of the thickness (i.e., "maximum thickness") perpendicular to the flat surface. The ratio C / D of the average maximum thickness C to the average equivalent circular diameter D of the toner particles is preferably in the range of 0.001 or more and 0.500 or less, more preferably in the range of 0.010 or more and 0.200 or less, and even more preferably in the range of 0.050 or more and 0.100 or less. When the ratio C / D is 0.001 or more, the strength of the toner particles is ensured, breakage due to stress during image formation is suppressed, and a decrease in charging due to exposure of the brilliant pigment and the resulting fogging are suppressed. On the other hand, when the ratio C / D is 0.500 or less, excellent brilliance can be obtained.

[0063] The above average maximum thickness C and average equivalent circular diameter D are measured by the following method. Place the toner on a smooth surface and vibrate it to disperse it evenly without unevenness. For 1000 brilliant toner particles, measure the maximum thickness C and the equivalent circular diameter D of the surface viewed from above after magnifying 1000 times with a color laser microscope "VK-9700" (manufactured by Keyence Corporation), and calculate their arithmetic mean values.

[0064] As a method for setting the value of the ratio C / D within the above range, for example, when manufacturing toner particles by the aggregation method, a method of controlling the ratio C / D by the stirring conditions in the aggregation process can be mentioned. Specifically, for example, at the stage of forming aggregated particles, the value of the ratio C / D becomes smaller by stirring at high speed and heating, and the value of the ratio C / D becomes larger by stirring at a lower speed and heating at a lower temperature.

[0065] (External additive) Examples of the external additive include inorganic particles. Examples of the inorganic particles include SiO 2 , TiO 2 , Al 2 O 3 , CuO, ZnO, SnO2 , CeO 2 , Fe 2 O 3 , MgO, BaO, CaO, K 2 O, Na 2 O, ZrO 2 , CaO·SiO 2 , K 2 O·(TiO 2 )n, Al 2 O 3 ·2SiO 2 , CaCO 3 , MgCO 3 , BaSO 4 , MgSO 4 etc. can be mentioned.

[0066] The surface of the inorganic particles as an external additive is preferably subjected to a hydrophobization treatment. The hydrophobization treatment is performed, for example, by immersing the inorganic particles in a hydrophobization treatment agent. The hydrophobization treatment agent is not particularly limited, and examples include silane-based coupling agents, silicone oils, titanate-based coupling agents, aluminum-based coupling agents, etc. These may be used alone or in combination of two or more. The amount of the hydrophobization treatment agent is usually, for example, 1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the inorganic particles.

[0067] Examples of the external additive also include resin particles (resin particles such as polystyrene, polymethyl methacrylate (PMMA), melamine resin, etc.), cleaning agents (for example, metal salts of higher fatty acids typified by zinc stearate, particles of fluorine-based high molecular weight substances), etc.

[0068] As the addition amount of the external additive, for example, 0.01% by mass or more and 5% by mass or less is preferable with respect to the toner particles, and 0.01% by mass or more and 2.0% by mass or less is more preferable.

[0069] (Method for manufacturing toner) Next, the method for manufacturing the toner according to this embodiment will be described. The toner according to this embodiment is obtained by externally adding an external additive to toner particles after manufacturing the toner particles.

[0070] The toner particles may be manufactured by either a dry process (e.g., kneading and pulverizing method, etc.) or a wet process (e.g., aggregation and consolidation method, suspension polymerization method, dissolution and suspension method, etc.). The manufacturing method of the toner particles is not particularly limited to these methods, and well-known manufacturing methods are adopted. Among these, it is preferable to obtain toner particles by the aggregation and consolidation method.

[0071] Specifically, for example, when manufacturing toner particles by the aggregation and consolidation method, a step of preparing a resin particle dispersion liquid in which resin particles serving as a binder resin are dispersed (resin particle dispersion liquid preparation step), a step of aggregating the resin particles (and other particles if necessary) in the resin particle dispersion liquid (or in the dispersion liquid after mixing other particle dispersion liquids if necessary) to form aggregated particles (aggregated particle formation step), and a step of heating the aggregated particle dispersion liquid in which the aggregated particles are dispersed to fuse and consolidate the aggregated particles to form toner particles (fusion and consolidation step) are performed to manufacture the toner particles.

[0072] Details of each step will be described below. In the following description, a method for obtaining toner particles containing a bright pigment and a release agent will be described, but other additives used as necessary may also be used.

[0073] - Resin Particle Dispersion Liquid Preparation Step - First, together with a resin particle dispersion liquid in which resin particles serving as a binder resin are dispersed, for example, a bright pigment dispersion liquid in which a bright pigment is dispersed and a release agent particle dispersion liquid in which release agent particles are dispersed are prepared.

[0074] Here, the resin particle dispersion liquid is prepared, for example, by dispersing resin particles in a dispersion medium with a surfactant.

[0075] Examples of the dispersion medium used for the resin particle dispersion liquid include aqueous media. Examples of the aqueous medium include water such as distilled water and ion-exchanged water, and alcohols. These may be used alone or in combination of two or more.

[0076] Examples of the surfactant include anionic surfactants such as sulfate ester salts, sulfonate salts, phosphate esters, and soaps; cationic surfactants such as amine salts and quaternary ammonium salts; nonionic surfactants such as polyethylene glycols, alkylphenol ethylene oxide adducts, and polyhydric alcohols. Among these, anionic surfactants and cationic surfactants are particularly mentioned. The nonionic surfactant may be used in combination with an anionic surfactant or a cationic surfactant. The surfactant may be used alone or in combination of two or more.

[0077] In the resin particle dispersion, examples of the method for dispersing the resin particles in the dispersion medium include general dispersion methods such as a rotary shear type homogenizer and a ball mill, a sand mill, and a dyno mill having media. Depending on the type of the resin particles, for example, the resin particles may be dispersed in the resin particle dispersion by using a phase inversion emulsification method. The phase inversion emulsification method is a method in which the resin to be dispersed is dissolved in a hydrophobic organic solvent in which the resin is soluble, a base is added to the organic continuous phase (O phase) and neutralized, and then an aqueous medium (W phase) is introduced, so that the resin is converted from W / O to O / W (so-called phase inversion), becomes a discontinuous phase, and the resin is dispersed in the form of particles in the aqueous medium.

[0078] The volume average particle diameter of the resin particles dispersed in the resin particle dispersion is preferably, for example, 0.01 μm or more and 1 μm or less, more preferably 0.08 μm or more and 0.8 μm or less, and even more preferably 0.1 μm or more and 0.6 μm or less. The volume average particle diameter of the resin particles is measured as the volume average particle diameter D50v, which is the particle diameter at which the cumulative distribution reaches 50% for all particles, by subtracting the cumulative distribution from the small particle diameter side with respect to volume for the divided particle size ranges (channels) using the particle size distribution obtained by measurement with a laser diffraction particle size distribution analyzer (for example, LA-700 manufactured by Horiba, Ltd.). The volume average particle diameter of the particles in other dispersion liquids is measured in the same manner.

[0079] As the content of the resin particles contained in the resin particle dispersion liquid, for example, 5 mass% or more and 50 mass% or less is preferable, and 10 mass% or more and 40 mass% or less is more preferable.

[0080] In the same manner as the resin particle dispersion liquid, for example, a fluorescent pigment dispersion liquid and a release agent particle dispersion liquid are also prepared. That is, regarding the volume average particle diameter of the particles, the dispersion medium, the dispersion method, and the content of the particles in the resin particle dispersion liquid, the same applies to the fluorescent pigment dispersed in the fluorescent pigment dispersion liquid and the release agent particles dispersed in the release agent particle dispersion liquid.

[0081] -Agglomerated Particle Formation Step- Next, the fluorescent pigment dispersion liquid and the release agent particle dispersion liquid are mixed with the resin particle dispersion liquid. Then, in the mixed dispersion liquid, the resin particles, the fluorescent pigment, and the release agent particles are hetero-aggregated to form agglomerated particles containing the resin particles, the fluorescent pigment, and the release agent particles, having a diameter close to the diameter of the target toner particles.

[0082] Specifically, for example, a flocculant is added to the mixed dispersion liquid, the pH of the mixed dispersion liquid is adjusted to acidic (for example, pH is 2 or more and 5 or less), and a dispersion stabilizer is added as necessary. Then, the mixture is heated to a temperature within the glass transition temperature of the resin particles (specifically, for example, the glass transition temperature of the resin particles - 30°C or more and the glass transition temperature of the resin particles - 10°C or less) to aggregate the particles dispersed in the mixed dispersion liquid and form agglomerated particles. In the agglomerated particle formation step, for example, in the mixed dispersion, while stirring with a rotary shear homogenizer, the above-mentioned aggregating agent is added at room temperature (for example, 25°C), the pH of the mixed dispersion is adjusted to acidic (for example, the pH is 2 or more and 5 or less), and after adding a dispersion stabilizer as necessary, the above-mentioned heating may be performed.

[0083] Examples of the aggregating agent include surfactants with opposite polarity to the surfactants used as dispersants added to the mixed dispersion, inorganic metal salts, and metal complexes with a valence of 2 or more. In particular, when a metal complex is used as the aggregating agent, the amount of surfactant used is reduced and the charging characteristics are improved. In addition, an additive (for example, a chelating agent) that forms a complex or a similar bond with the metal ion of the aggregating agent may be used as necessary, but in this embodiment, an aminocarboxylic acid compound may serve as a chelating agent.

[0084] The addition of the aminocarboxylic acid compound is not limited to a certain step. The addition of the aminocarboxylic acid compound may be performed in at least one selected from the group consisting of the addition of the aggregating agent, after adjusting the pH to acidic, after heating, and the fusion / union step described later. Examples of the addition amount of the aminocarboxylic acid compound include a range of 0.01 parts by mass or more and 10.0 parts by mass or less with respect to 100 parts by mass of the total amount of solids (for example, resin particles, bright pigments, and release agents) contained in the mixed dispersion. From the viewpoint of suppressing toner leakage, a range of 0.05 parts by mass or more and 5.0 parts by mass or less is preferable, and a range of 0.1 parts by mass or more and 3.0 parts by mass or less is more preferable.

[0085] Examples of the inorganic metal salt include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, aluminum sulfate, and inorganic metal salt polymers such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide.

[0086] -Fusion / Union Step- Next, with respect to the aggregated particle dispersion in which the aggregated particles are dispersed, for example, it is heated to a temperature equal to or higher than the glass transition temperature of the resin particles (for example, a temperature equal to or higher than 10 to 30 °C higher than the glass transition temperature of the resin particles) to fuse and combine the aggregated particles to form toner particles.

[0087] Through the above steps, toner particles are obtained. In addition, after obtaining the aggregated particle dispersion in which the aggregated particles are dispersed, the aggregated particle dispersion and the resin particle dispersion in which the resin particles are dispersed are further mixed, and they are aggregated so that the resin particles further adhere to the surface of the aggregated particles to form second aggregated particles, and the second aggregated particle dispersion in which the second aggregated particles are dispersed is heated to fuse and combine the second aggregated particles to form toner particles having a core / shell structure. Toner particles may be manufactured through these steps. In addition, when forming toner particles having a core / shell structure, an aminocarboxylic acid compound may be added in the step of forming the second aggregated particles, and an aminocarboxylic acid compound may also be added in the step of fusing and combining the second aggregated particles to form toner particles having a core / shell structure.

[0088] Here, after the fusion and combination step is completed, the toner particles formed in the solution are obtained as toner particles in a dried state through known washing steps, solid-liquid separation steps, and drying steps. In the washing step, it is preferable to perform substitution washing sufficiently with ion-exchanged water from the viewpoint of chargeability. Also, the solid-liquid separation step is not particularly limited, but from the viewpoint of productivity, it is preferable to perform suction filtration, pressure filtration, etc. Also, the drying step is not particularly limited in method either, but from the viewpoint of productivity, it is preferable to perform freeze drying, airflow drying, fluidized drying, vibration type fluidized drying, etc.

[0089] And the toner according to this embodiment is manufactured, for example, by adding and mixing an external additive to the obtained toner particles in a dried state. The mixing may be performed, for example, by a V blender, a Henschel mixer, a Lodige mixer, etc. Further, if necessary, coarse particles of the toner may be removed using a vibration sieve, an air classifier, etc.

[0090] <Electrostatic charge image developer> The electrostatic charge image developer according to this embodiment includes at least the toner according to this embodiment. The electrostatic charge image developer according to this embodiment may be a one-component developer containing only the toner according to this embodiment, or a two-component developer in which the toner and a carrier are mixed.

[0091] There is no particular limitation on the carrier, and known carriers can be mentioned. Examples of the carrier include a coated carrier in which a coating resin is coated on the surface of a core material made of magnetic powder; a magnetic powder-dispersed carrier in which magnetic powder is dispersed and blended in a matrix resin; a resin-impregnated carrier in which porous magnetic powder is impregnated with resin; and the like. Note that the magnetic powder-dispersed carrier and the resin-impregnated carrier may be carriers in which the constituent particles of the carrier are used as a core material and coated with a coating resin.

[0092] Examples of the magnetic powder include magnetic metals such as iron, nickel, and cobalt, and magnetic oxides such as ferrite and magnetite.

[0093] Examples of the coating resin and the matrix resin include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic ester copolymer, straight silicone resin or its modified product containing an organosiloxane bond, fluororesin, polyester, polycarbonate, phenol resin, epoxy resin, and the like. Note that the coating resin and the matrix resin may contain other additives such as conductive particles. Examples of the conductive particles include metals such as gold, silver, and copper, and particles such as carbon black, titanium oxide, zinc oxide, tin oxide, barium sulfate, aluminum borate, and potassium titanate.

[0094] Here, to coat the surface of the core material with a coating resin, methods such as coating with a coating resin and, if necessary, a coating layer-forming solution in which various additives are dissolved in an appropriate solvent can be mentioned. The solvent is not particularly limited and may be selected in consideration of the coating resin to be used, coating applicability, etc. Specific resin coating methods include an immersion method in which the core material is immersed in a coating layer-forming solution, a spray method in which the coating layer-forming solution is sprayed onto the surface of the core material, a fluidized bed method in which the coating layer-forming solution is sprayed while the core material is suspended by flowing air, a kneader coater method in which the carrier core material and the coating layer-forming solution are mixed in a kneader coater and the solvent is removed, etc.

[0095] In the two-component developer, the mixing ratio (mass ratio) of toner and carrier is preferably toner:carrier = 1:100 to 30:100, and more preferably 3:100 to 20:100.

[0096] <Image forming apparatus / Image forming method> The image forming apparatus / image forming method according to this embodiment will be described. The image forming apparatus according to this embodiment includes an image carrier, a charging means for charging the surface of the image carrier, an electrostatic charge image forming means for forming an electrostatic charge image on the charged surface of the image carrier, a developing means for accommodating an electrostatic charge image developer and developing the electrostatic charge image formed on the surface of the image carrier as a toner image with the electrostatic charge image developer, a transfer means for transferring the toner image formed on the surface of the image carrier to the surface of a recording medium, and a fixing means for fixing the toner image transferred to the surface of the recording medium. And, as the electrostatic charge image developer, the electrostatic charge image developer according to this embodiment is applied.

[0097] In the image forming apparatus according to the present embodiment, a charging step of charging the surface of the image carrier, an electrostatic charge image forming step of forming an electrostatic charge image on the charged surface of the image carrier, a developing step of developing the electrostatic charge image formed on the surface of the image carrier as a toner image by the electrostatic charge image developer according to the present embodiment, a transfer step of transferring the toner image formed on the surface of the image carrier to the surface of a recording medium, and a fixing step of fixing the toner image transferred to the surface of the recording medium are performed (image forming method according to the present embodiment).

[0098] The image forming apparatus according to the present embodiment further includes cleaning means having a cleaning blade. When the image forming apparatus is a direct transfer type apparatus that directly transfers the toner image formed on the surface of the image carrier to a recording medium, examples of the cleaning means include cleaning means having a cleaning blade for cleaning the surface of the image carrier. Further, when the image forming apparatus is an intermediate transfer type apparatus that primarily transfers the toner image formed on the surface of the image carrier to the surface of an intermediate transfer member and secondarily transfers the toner image transferred to the surface of the intermediate transfer member to the surface of a recording medium, the cleaning means may be cleaning means having a cleaning blade for cleaning the surface of the image carrier, or may be cleaning means having a cleaning blade for cleaning the surface of the intermediate transfer member. Further, the image forming apparatus may be a well-known image forming apparatus such as an apparatus including charge removal means for irradiating the surface of the image carrier with charge removal light for charge removal after transfer of the toner image and before charging. In the case of an intermediate transfer type apparatus, for example, the transfer means has a configuration including an intermediate transfer member on which a toner image is transferred to the surface, a primary transfer means for primarily transferring the toner image formed on the surface of the image carrier to the surface of the intermediate transfer member, and a secondary transfer means for secondarily transferring the toner image transferred to the surface of the intermediate transfer member to the surface of a recording medium.

[0099] In the image forming apparatus according to the present embodiment, for example, a portion including developing means may be a cartridge structure (process cartridge) that is detachable from the image forming apparatus. As the process cartridge, for example, a process cartridge including developing means that stores the electrostatic charge image developer according to the present embodiment is preferably used.

[0100] Hereinafter, an example of the image forming apparatus according to the present embodiment is shown, but the present invention is not limited thereto. Note that the main parts shown in the drawings will be described, and the description of the others will be omitted.

[0101] FIG. 1 is a schematic configuration diagram showing the image forming apparatus according to the present embodiment. The image forming apparatus shown in FIG. 1 includes first to fourth image forming units 10Y, 10M, 10C, and 10K (image forming means) of an electrophotographic system that output images of respective colors of yellow (Y), magenta (M), cyan (C), and black (K) based on color-separated image data. These image forming units (hereinafter, may be simply referred to as "units") 10Y, 10M, 10C, and 10K are arranged side by side at a predetermined distance from each other in the horizontal direction. Note that these units 10Y, 10M, 10C, and 10K may be process cartridges that are detachable from the image forming apparatus.

[0102] Above the drawings of the respective units 10Y, 10M, 10C, and 10K, an intermediate transfer belt 20 as an intermediate transfer member extends through each unit. The intermediate transfer belt 20 is provided by being wound around a drive roll 22 and a support roll 24 that is in contact with the inner surface of the intermediate transfer belt 20 and is arranged at intervals in the left-to-right direction in the figure, and is adapted to travel in the direction from the first unit 10Y to the fourth unit 10K. Note that the support roll 24 is applied with a force in a direction away from the drive roll 22 by a spring or the like (not shown), and tension is applied to the intermediate transfer belt 20 wound around both of them. Further, an intermediate transfer member cleaning device 30 is provided on the side surface of the image holding body of the intermediate transfer belt 20 so as to face the drive roll 22. The intermediate transfer member cleaning device 30 has a cleaning blade for cleaning the surface of the intermediate transfer belt 20. Also, each of the developing devices (developing means) 4Y, 4M, 4C, and 4K of the respective units 10Y, 10M, 10C, and 10K is supplied with toner including four colors of toner, namely yellow, magenta, cyan, and black, stored in toner cartridges 8Y, 8M, 8C, and 8K.

[0103] Since the first to fourth units 10Y, 10M, 10C, and 10K have the same configuration, here, the first unit 10Y that forms a yellow image disposed on the upstream side in the traveling direction of the intermediate transfer belt will be described as a representative. Note that for parts equivalent to the first unit 10Y, reference numerals with magenta (M), cyan (C), and black (K) attached instead of yellow (Y) are used, and the description of the second to fourth units 10M, 10C, and 10K is omitted.

[0104] The first unit 10Y has a photoreceptor 1Y that acts as an image holding member. Around the photoreceptor 1Y, there are arranged in order a charging roll (an example of charging means) 2Y that charges the surface of the photoreceptor 1Y to a predetermined potential, an exposure device (an example of electrostatic charge image forming means) 3 that exposes the charged surface with a laser beam 3Y based on a color-separated image signal to form an electrostatic charge image, a developing device (an example of developing means) 4Y that supplies toner charged to the electrostatic charge image to develop the electrostatic charge image, a primary transfer roll 5Y (an example of primary transfer means) that transfers the developed toner image onto the intermediate transfer belt 20, and a photoreceptor cleaning device (an example of cleaning means) 6Y that removes the toner remaining on the surface of the photoreceptor 1Y after primary transfer. The photoreceptor cleaning device 6Y has a cleaning blade that cleans the surface of the photoreceptor 1Y. Note that the primary transfer roll 5Y is arranged inside the intermediate transfer belt 20 and is provided at a position facing the photoreceptor 1Y. Further, bias power supplies (not shown) for applying a primary transfer bias are connected to the respective primary transfer rolls 5Y, 5M, 5C, and 5K. Each bias power supply varies the transfer bias applied to each primary transfer roll under the control of a control unit (not shown).

[0105] Hereinafter, the operation of forming a yellow image in the first unit 10Y will be described. First, prior to the operation, the surface of the photoreceptor 1Y is charged to a potential of -600 V to -800 V by the charging roll 2Y. The photoreceptor 1Y is formed by laminating a photosensitive layer on a conductive substrate (for example, volume resistivity at 20°C: 1 × 10 -6 Ωcm or less). This photosensitive layer is usually of high resistance (resistance of a general resin), but has the property that when irradiated with the laser beam 3Y, the specific resistance of the portion irradiated with the laser beam changes. Therefore, the laser beam 3Y is output via the exposure device 3 in accordance with the yellow image data sent from a control unit (not shown) to the charged surface of the photoreceptor 1Y. The laser beam 3Y is irradiated onto the photosensitive layer on the surface of the photoreceptor 1Y, whereby an electrostatic charge image of the yellow image pattern is formed on the surface of the photoreceptor 1Y.

[0106] The electrostatic charge image is an image formed on the surface of the photoreceptor 1Y due to charging. By the laser beam 3Y, the specific resistance of the irradiated portion of the photosensitive layer decreases, and the charged charges on the surface of the photoreceptor 1Y flow. On the other hand, it is a so-called negative latent image formed by the remaining charges in the portion not irradiated with the laser beam 3Y. The electrostatic charge image formed on the photoreceptor 1Y is rotated to a predetermined development position as the photoreceptor 1Y travels. And at this development position, the electrostatic charge image on the photoreceptor 1Y is visualized as a toner image (developed image) by the developing device 4Y.

[0107] Inside the developing device 4Y, for example, an electrostatic charge image developer containing at least yellow toner and carrier is accommodated. The yellow toner is triboelectrically charged by being agitated inside the developing device 4Y, has the same polarity (negative polarity) as the charged charges on the photoreceptor 1Y, and is held on a developer roll (an example of a developer holding member). And as the surface of the photoreceptor 1Y passes through the developing device 4Y, the yellow toner electrostatically adheres to the discharged latent image portion on the surface of the photoreceptor 1Y, and the latent image is developed by the yellow toner. The photoreceptor 1Y on which the yellow toner image is formed continues to travel at a predetermined speed, and the toner image developed on the photoreceptor 1Y is conveyed to a predetermined primary transfer position.

[0108] When the yellow toner image on the photoreceptor 1Y is conveyed to the primary transfer, a primary transfer bias is applied to the primary transfer roll 5Y, and the electrostatic force from the photoreceptor 1Y toward the primary transfer roll 5Y acts on the toner image, and the toner image on the photoreceptor 1Y is transferred onto the intermediate transfer belt 20. The transfer bias applied at this time is the opposite polarity (+) to the polarity (-) of the toner. For example, in the first unit 10Y, it is controlled to +10 μA by a control unit (not shown). On the other hand, the toner remaining on the photoreceptor 1Y is removed and recovered by the photoreceptor cleaning device 6Y.

[0109] In addition, the primary transfer bias applied to the primary transfer rolls 5M, 5C, and 5K after the second unit 10M is also controlled in accordance with the first unit. In this way, the intermediate transfer belt 20 onto which the yellow toner image has been transferred in the first unit 10Y is sequentially conveyed through the second to fourth units 10M, 10C, and 10K, and the toner images of each color are superimposed and multi-transferred.

[0110] The intermediate transfer belt 20 onto which the four-color toner images have been multi-transferred through the first to fourth units reaches the secondary transfer unit composed of the intermediate transfer belt 20, the support roll 24 in contact with the inner surface of the intermediate transfer belt, and the secondary transfer roll (an example of secondary transfer means) 26 disposed on the image holding surface side of the intermediate transfer belt 20. On the other hand, the recording paper (an example of a recording medium) P is fed at a predetermined timing into the gap where the secondary transfer roll 26 and the intermediate transfer belt 20 are in contact via a feeding mechanism, and a secondary transfer bias is applied to the support roll 24. The transfer bias applied at this time is the (-) polarity of the same polarity as the polarity (-) of the toner, and the electrostatic force from the intermediate transfer belt 20 toward the recording paper P acts on the toner image, and the toner image on the intermediate transfer belt 20 is transferred onto the recording paper P. Note that the secondary transfer bias at this time is determined according to the resistance detected by resistance detection means (not shown) for detecting the resistance of the secondary transfer unit, and is voltage-controlled.

[0111] Thereafter, the recording paper P is fed into the pressure contact portion (nip portion) of a pair of fixing rolls in the fixing device (an example of fixing means) 28, and the toner image is fixed onto the recording paper P, and a fixed image is formed.

[0112] Examples of the recording paper P for transferring the toner image include plain paper used in electrophotographic copiers, printers, etc. Examples of the recording medium other than the recording paper P also include OHP sheets. In order to further improve the smoothness of the image surface after fixing, it is preferable that the surface of the recording paper P is also smooth. For example, coated paper obtained by coating the surface of plain paper with resin or the like, art paper for printing, etc. are preferably used.

[0113] The recording paper P on which the fixing of the color image is completed is carried out toward the discharging unit, and a series of color image forming operations are terminated.

[0114] [Process cartridge / Toner cartridge] The process cartridge according to the present embodiment will be described. The process cartridge according to the present embodiment accommodates the electrostatic charge image developer according to the present embodiment, and includes developing means for developing the electrostatic charge image formed on the surface of the image carrier as a toner image, and is a process cartridge that is detachable from the image forming apparatus.

[0115] Note that the process cartridge according to the present embodiment is not limited to the above configuration, and may be configured to include a developing device and at least one selected from other means such as, for example, an image carrier, charging means, electrostatic charge image forming means, and transfer means, as necessary.

[0116] Hereinafter, an example of the process cartridge according to the present embodiment is shown, but it is not necessarily limited thereto. Note that the main parts shown in the drawings will be described, and the description of the others will be omitted.

[0117] FIG. 2 is a schematic configuration diagram showing the process cartridge according to the present embodiment. The process cartridge 200 shown in FIG. 2 is configured by integrally combining and holding, for example, a photosensitive member 107 (an example of an image carrier), a charging roll 108 (an example of charging means) provided around the photosensitive member 107, a developing device 111 (an example of developing means), and a photosensitive member cleaning device 113 (an example of cleaning means) having a cleaning blade for cleaning the surface of the photosensitive member 107, by a housing 117 provided with an attachment rail 116 and an opening 118 for exposure, and is formed as a cartridge. In FIG. 2, reference numeral 109 denotes an exposure device (an example of electrostatic charge image forming means), 112 denotes a transfer device (an example of transfer means), 115 denotes a fixing device (an example of fixing means), and 300 denotes a recording paper (an example of a recording medium).

[0118] Next, the toner cartridge according to this embodiment will be described. The toner cartridge according to this embodiment is a toner cartridge that houses the toner according to this embodiment and is detachable from the image forming apparatus. The toner cartridge houses replenishing toner for supplying to developing means provided in the image forming apparatus.

[0119] Note that the image forming apparatus shown in FIG. 1 is an image forming apparatus having a configuration in which toner cartridges 8Y, 8M, 8C, and 8K are detachable, and developing devices 4Y, 4M, 4C, and 4K are connected to toner cartridges corresponding to the respective developing devices (colors) by toner supply pipes (not shown). Further, when the toner housed in the toner cartridge becomes less, the toner cartridge is replaced.

Example

[0120] Examples will be described below, but the present invention is not limited to these examples in any way. In the following description, unless otherwise specified, all "parts" and "%" are based on mass.

[0121] [Preparation of each particle dispersion liquid] <Preparation of the fluorescent pigment dispersion liquid> (Preparation of the fluorescent pigment dispersion liquid (1)) · Fluorescent pigment (1) (aluminum pigment, product name: Toyo Aluminum's 2173EA, volume average particle diameter: 7.1 μm): 100 parts · Anionic surfactant (Neogen R of Dai-ichi Kogyo Seiyaku Co., Ltd.): 1.5 parts · Ion-exchanged water: 900 parts The above materials were mixed and subjected to dispersion treatment with an emulsifying disperser (Cabitron CR1010 of Taiheiyo Kikai Co., Ltd.) for 1 hour to obtain a fluorescent pigment dispersion liquid (solid content concentration: 10% by mass).

[0122] <Preparation of the polyester resin particle dispersion liquid> Into a reaction vessel equipped with a stirrer, thermometer, condenser, and nitrogen gas inlet tube, 80 mol parts of polyoxypropylene(2,2)-2,2-bis(4-hydroxyphenyl)propane, 10 mol parts of ethylene glycol, 10 mol parts of cyclohexanediol, 80 mol parts of terephthalic acid, 10 mol parts of isophthalic acid, and 10 mol parts of n-dodecenyl succinic acid were charged, and the inside of the reaction vessel was replaced with dry nitrogen gas. Then, 0.25 part by mass of titanium tetrabutoxide was charged as a catalyst with respect to 100 parts by mass of the monomer components. After stirring and reacting at 170 °C for 3 hours under a nitrogen gas stream, the temperature was further raised to 210 °C over 1 hour, the pressure inside the reaction vessel was reduced to 3 kPa, and the mixture was stirred and reacted under reduced pressure for 13 hours to obtain a polyester resin.

[0123] Next, 200 parts by mass of the polyester resin, 100 parts by mass of methyl ethyl ketone, and 70 parts by mass of isopropyl alcohol were placed in a 3-liter jacketed reaction tank (manufactured by Tokyo Rika Kikai Co., Ltd.: BJ-30N) equipped with a condenser, thermometer, water dropping device, and anchor blades, and the resin was dissolved while stirring and mixing at 100 rpm while maintaining the temperature at 70 °C in a water circulation type constant temperature bath. Then, the stirring speed was set to 150 rpm, the water circulation type constant temperature bath was set to 66 °C, 10 parts by mass of 10% by mass aqueous ammonia (reagent) was added over 10 minutes, and then ion-exchanged water kept at 66 °C was added dropwise at a rate of 5 parts by mass / min for a total of 600 parts by mass to cause phase inversion, obtaining an emulsion. 600 parts of the obtained emulsion and 525 parts by mass of ion-exchanged water were placed in a 2-liter eggplant flask and set in an evaporator (manufactured by Tokyo Rika Kikai Co., Ltd.) equipped with a vacuum control unit via a trap ball. While rotating the eggplant flask, it was heated in a hot water bath at 60 °C, and the pressure was reduced to 7 kPa while paying attention to bumping to remove the solvent. When the solvent recovery amount reached 825 parts by mass, the pressure was returned to normal pressure, and the eggplant flask was cooled with water to obtain a dispersion in which resin particles with a volume average particle diameter of 170 nm were dispersed. Ion-exchanged water was added to obtain a polyester resin particle dispersion with a solid content concentration of 20% by mass.

[0124] <Preparation of release agent particle dispersion> · Paraffin wax (manufactured by Nippon Seiro Co., Ltd., FNP92, endothermic peak onset temperature 81°C): 45 parts by mass · Anionic surfactant (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., Neogen RK): 5 parts by mass · Ion-exchanged water: 200 parts by mass The above were mixed and heated to 95°C, and dispersed using a homogenizer (Ultra-Turrax T50 manufactured by IKA). Thereafter, dispersion treatment was performed using a Manton Gaulin high-pressure homogenizer (manufactured by Gaulin), and a release agent particle dispersion liquid (solid content concentration: 20% by mass) in which the release agent particles were dispersed was prepared. The volume average particle diameter of the release agent particles was 0.19 μm.

[0125] [Preparation of toner] [Example 1] · Polyester resin particle dispersion liquid: 450 parts · Glitter pigment dispersion liquid (1): 50 parts · Release agent particle dispersion liquid: 22 parts · Nonionic surfactant (Igepal CA897): 1.40 parts The above raw materials were placed in a 2 L cylindrical stainless steel container (diameter 30 cm), and dispersion treatment was performed for 10 minutes at 4000 rpm while applying a shearing force using a homogenizer (Ultra-Turrax T50 of IKA). Next, 1.75 parts of a 10% by mass aqueous solution of aluminum poly chloride and 2 parts of trisodium ethylenediaminetetraacetate (manufactured by Fujifilm Wako Pure Chemical Corporation, product name: EDTA·3Na), which is an aminocarboxylic acid compound, were gradually added dropwise, the rotation speed of the homogenizer was set to 5000 rpm, and dispersion treatment was performed for 15 minutes to obtain a raw material dispersion liquid. Next, the raw material dispersion liquid was transferred to a polymerization kettle equipped with a stirring device having a two-blade stirring blade and a thermometer, heating was started using a mantle heater while stirring at a stirring rotation speed of 200 rpm, and it was held at 54°C for 2 hours. At this time, the pH of the raw material dispersion liquid was controlled to 2.2 to 3.5 using 0.3N nitric acid and 1N aqueous sodium hydroxide solution.

[0126] Next, 30 parts of the polyester resin particle dispersion was added dropwise over 20 minutes, and after leaving it standing for 15 minutes, an additional 20 parts of the polyester resin particle dispersion was added dropwise over 20 minutes. The temperature was further raised to 56°C, and the aggregated particles were adjusted while confirming the particle size and morphology with an optical microscope and a Multi-Sizer II. Then, after raising the pH to 8.0, the temperature was raised to 67.5°C. Further, while maintaining the temperature at 67.5°C, the pH was lowered to 6.0, the heating was stopped after 1 hour, and it was cooled at a temperature decrease rate of 1.0°C / min. Then, it was sieved with a 20 μm mesh, washed with water repeatedly, and dried with a vacuum dryer to obtain core-shell particles.

[0127] Next, after raising the pH to 8.0, the temperature was raised to 67.5°C to fuse the aggregated particles. While maintaining the temperature at 67.5°C, the pH was lowered to 6.0, the heating was stopped after 1 hour, and it was cooled at a temperature decrease rate of 0.1°C / min. Then, it was sieved with a 20 μm mesh, washed with water repeatedly, and dried with a vacuum dryer to obtain toner particles (1). The volume average particle diameter of the toner particles (1) was 10.5 μm, and the ratio C / D was 0.138.

[0128] 100 parts of the obtained toner particles (1) and 1.5 parts of hydrophobic silica (RY50 of Nippon Aerosil) were mixed with a Henschel mixer at a peripheral speed of 33 m / s for 2 minutes. Then, it was sieved with a vibrating sieve having an opening of 45 μm to obtain externally added toner (1).

[0129] <Example 2> As the aminocarboxylic acid compound, 2 parts of tetrasodium ethylenediaminetetraacetate (product name: EDTA·4Na, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was used instead of 2 parts of trisodium ethylenediaminetetraacetate. In the same manner as in Example 1, toner particles (2) and toner (2) were obtained. The volume average particle diameter of the obtained toner particles (2) was 10.4 μm, and the ratio C / D was 0.074.

[0130] <Example 3> As the aminocarboxylic acid compound, toner particles (3) and toner (3) were obtained in the same manner as in Example 1, except that 5 parts of trisodium ethylenediaminetetraacetate (manufactured by Fujifilm Wako Pure Chemical Corporation, product name: EDTA·3Na) were used instead of 2 parts of trisodium ethylenediaminetetraacetate. The volume average particle diameter of the obtained toner particles (3) was 10.6 μm, and the ratio C / D was 0.482.

[0131] <Example 4> As the aminocarboxylic acid compound, toner particles (4) and toner (4) were obtained in the same manner as in Example 1, except that 0.4 part of trisodium ethylenediaminetetraacetate (manufactured by Fujifilm Wako Pure Chemical Corporation, product name: EDTA·3Na) was used instead of 2 parts of trisodium ethylenediaminetetraacetate. The volume average particle diameter of the obtained toner particles (4) was 10.1 μm, and the ratio C / D was 0.153.

[0132] <Example 5> As the aminocarboxylic acid compound, toner particles (5) and toner (5) were obtained in the same manner as in Example 1, except that 10 parts of trisodium ethylenediaminetetraacetate (manufactured by Fujifilm Wako Pure Chemical Corporation, product name: EDTA·3Na) were used instead of 2 parts of trisodium ethylenediaminetetraacetate. The volume average particle diameter of the obtained toner particles (5) was 10.9 μm, and the ratio C / D was 0.204.

[0133] <Example 6> As the aminocarboxylic acid compound, toner particles (6) and toner (6) were obtained in the same manner as in Example 1, except that 5 parts of trisodium ethylenediaminetetraacetate (manufactured by Fujifilm Wako Pure Chemical Corporation, product name: EDTA·3Na) were used instead of 2 parts of trisodium ethylenediaminetetraacetate. The volume average particle diameter of the obtained toner particles (6) was 10.4 μm, and the ratio C / D was 0.257.

[0134] <Example 7> As the aminocarboxylic acid compound, toner particles (7) and toner (7) were obtained in the same manner as in Example 1, except that 2 parts of trisodium hydroxyethylethylenediaminetriacetate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name: HEDTA·3Na) were used instead of 2 parts of trisodium ethylenediaminetetraacetate. The volume average particle diameter of the obtained toner particles (7) was 10.2 μm, and the ratio C / D was 0.184.

[0135] <Example 8> As the aminocarboxylic acid compound, toner particles (8) and toner (8) were obtained in the same manner as in Example 1, except that 2 parts of trisodium diethylenetriaminepentaacetate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name: DTPA·3Na) were used instead of 2 parts of trisodium ethylenediaminetetraacetate. The volume average particle diameter of the obtained toner particles (8) was 10.6 μm, and the ratio C / D was 0.302.

[0136] <Example 9> As the aminocarboxylic acid compound, toner particles (9) and toner (9) were obtained in the same manner as in Example 1, except that 2 parts of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name: DOTA) were used instead of 2 parts of trisodium ethylenediaminetetraacetate. The volume average particle diameter of the obtained toner particles (9) was 11.0 μm, and the ratio C / D was 0.118.

[0137] <Example 10> As the aminocarboxylic acid compound, toner particles (10) and toner (10) were obtained in the same manner as in Example 1, except that 2 parts of disodium ethylenediaminetetraacetate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name: EDTA·2Na) were used instead of 2 parts of trisodium ethylenediaminetetraacetate. The volume average particle diameter of the obtained toner particles (10) was 9.9 μm, and the ratio C / D was 0.098.

[0138] <Example 11> As the aminocarboxylic acid compound, toner particles (11) and toner (11) were obtained in the same manner as in Example 1, except that 2 parts of disodium ethylenediaminetetraacetate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name: EDTA·2Na) were used instead of 2 parts of trisodium ethylenediaminetetraacetate. The volume average particle diameter of the obtained toner particles (11) was 10.3 μm, and the ratio C / D was 0.354.

[0139] <Comparative Example 1> Toner particles (C1) and toner (C1) were obtained in the same manner as in Example 1, except that no aminocarboxylic acid compound was added. The volume average particle diameter of the obtained toner particles (C1) was 10.3 μm, and the ratio C / D was 0.164.

[0140] <Example 12> As the aminocarboxylic acid compound, toner particles (12) and toner (12) were obtained in the same manner as in Example 1, except that 0.1 part of trisodium ethylenediaminetetraacetate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name: EDTA·3Na) was used instead of 2 parts of trisodium ethylenediaminetetraacetate. The volume average particle diameter of the obtained toner particles (12) was 10.5 μm, and the ratio C / D was 0.170.

[0141] <Example 13> As the aminocarboxylic acid compound, toner particles (13) and toner (13) were obtained in the same manner as in Example 1, except that 20 parts of trisodium ethylenediaminetetraacetate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name: EDTA·3Na) were used instead of 2 parts of trisodium ethylenediaminetetraacetate. The volume average particle diameter of the obtained toner particles (13) was 10.2 μm, and the ratio C / D was 0.201.

[0142] <Example 14> As the aminocarboxylic acid compound, toner particles (14) and toner (14) were obtained in the same manner as in Example 1, except that 2 parts of trisodium ethylenediaminetetraacetate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name: EDTA·3Na) were used instead of 2 parts of trisodium ethylenediaminetetraacetate. The volume average particle diameter of the obtained toner particles (14) was 10.0 μm, and the ratio C / D was 0.008.

[0143] <Example 15> As the aminocarboxylic acid compound, toner particles (15) and toner (15) were obtained in the same manner as in Example 1, except that 2 parts of trisodium ethylenediaminetetraacetate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name: EDTA·3Na) were used instead of 2 parts of trisodium ethylenediaminetetraacetate. The volume average particle diameter of the obtained toner particles (15) was 10.6 μm, and the ratio C / D was 0.754.

[0144] <Example 16> As the aminocarboxylic acid compound, toner particles (16) and toner (16) were obtained in the same manner as in Example 1, except that 2 parts of L-asparagine monohydrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name: L-asparagine monohydrate) were used instead of 2 parts of trisodium ethylenediaminetetraacetate. The volume average particle diameter of the obtained toner particles (16) was 10.8 μm, and the ratio C / D was 0.380.

[0145] <Example 17> As the aminocarboxylic acid compound, toner particles (17) and toner (17) were obtained in the same manner as in Example 1, except that 2 parts of triethylenetetraminehexaacetic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name: TTHA) were used instead of 2 parts of trisodium ethylenediaminetetraacetate. The volume average particle diameter of the obtained toner particles (17) was 10.3 μm, and the ratio C / D was 0.172.

[0146] <Example 18> As the aminocarboxylic acid compound, toner particles (18) and toner (18) were obtained in the same manner as in Example 1, except that 2 parts of disodium nitrilotriacetate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name: disodium nitrilotriacetate) were used instead of 2 parts of trisodium ethylenediaminetetraacetate. The volume average particle diameter of the obtained toner particles (18) was 10.5 μm, and the ratio C / D was 0.198.

[0147] <Example 19> As the aminocarboxylic acid compound, toner particles (19) and toner (19) were obtained in the same manner as in Example 1, except that 2 parts of tetrasodium 3-hydroxy-2,2'-iminodisuccinate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name: HIDS) were used instead of 2 parts of trisodium ethylenediaminetetraacetate. The volume average particle diameter of the obtained toner particles (19) was 10.3 μm, and the ratio C / D was 0.187.

[0148] <Comparative Example 2> Toner particles (C2) and toner (C2) were obtained in the same manner as in Example 1, except that 2 parts of trisodium citrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name: trisodium citrate) were used instead of the aminocarboxylic acid compound. The volume average particle diameter of the obtained toner particles (C2) was 10.5 μm, and the ratio C / D was 0.216.

[0149] <Example 20> As the aminocarboxylic acid compound, toner particles (20) and toner (20) were obtained in the same manner as in Example 1, except that 2 parts of N-(2,6-dimethylphenylcarbamoylmethyl)iminodiacetic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name: N-(2,6-dimethylphenylcarbamoylmethyl)iminodiacetic acid) were used instead of 2 parts of trisodium ethylenediaminetetraacetate. The volume average particle diameter of the obtained toner particles (20) was 10.3 μm, and the ratio C / D was 0.214.

[0150] The carboxyl group number, amino group number, and pH of the aminocarboxylic acid compound or trisodium citrate used in the above Examples and Comparative Examples are shown in Table 1. Table 1 also shows the results of measuring the content (ppm) of the aminocarboxylic acid compound or trisodium citrate contained in the toner particles obtained in the above Examples and Comparative Examples by the aforementioned method.

[0151] [Evaluation] [Preparation of Carrier] 100 parts by mass of ferrite particles (manufactured by Powdertech Co., Ltd., average particle size 50 μm) and 1.5 parts by mass of polymethyl methacrylate resin (manufactured by Mitsubishi Chemical Corporation, weight average molecular weight 95,000, component ratio of weight average molecular weight 10,000 or less is 5% by mass) were put into a pressure kneader together with 500 parts by mass of toluene, stirred and mixed at room temperature (25 °C) for 15 minutes, then heated to 70 °C while mixing under reduced pressure to distill off toluene, and then cooled and classified using a 105 μm sieve to obtain a resin-coated ferrite carrier.

[0152] [Preparation of Developer] The obtained toner and the resin-coated ferrite carrier were mixed to prepare a developer with a toner concentration of 7% by mass.

[0153] [Toner Slippage Evaluation] The obtained developer was filled into a developing device of a commercially available image forming apparatus (Docu Centre III C7600, manufactured by Fuji Xerox Co., Ltd.) having an intermediate transfer belt. In an environment of 28 °C and 85% RH, after forming an image with an image density of 20% on plain paper (manufactured by Fuji Xerox Co., Ltd., product name: P paper A4) with 5000 pv (pv = number of image forming processing sheets (print volume)), a full-surface halftone 50% image was formed. After attaching cellophane tape to the surface of the intermediate transfer belt after forming the above full-surface halftone 50% image, peeling it off, attaching the peeled cellophane tape to white paper again, checking the toner on the white paper, observing the degree of toner slippage, and evaluating the degree of toner slippage of the residual toner according to the following criteria. The results are shown in Table 1. A: No toner leakage was confirmed. B: Slight toner leakage was confirmed, but it is within the practical allowable range. C: Slight toner leakage was confirmed, but it is within the practical allowable range. D: Partial toner leakage was confirmed, but it is within the practical allowable range. E: Toner leakage was confirmed across the entire cellophane tape and is not suitable for practical use.

[0154] <Ghosting evaluation> The obtained developer was filled into the developing unit of a commercially available electrophotographic copying machine (Docu Centre III C7600, manufactured by Fuji Xerox Co., Ltd.) having an intermediate transfer belt. Ghosting evaluation was carried out when forming 30 consecutive images with an image density of 1% on plain paper (manufactured by Fuji Xerox Co., Ltd., product name: P paper A4) in an environment of 28°C and 85% RH. A: No ghosting was observed on all 30 sheets. B: Slight ghosting was observed on one sheet, but it is within the practical allowable range. C: Slight ghosting was observed on multiple sheets, but it is within the practical allowable range. D: Obvious ghosting was observed on multiple sheets and is not suitable for practical use.

[0155] <Glossiness evaluation> The obtained developer was filled into the developing unit of a commercially available electrophotographic copying machine (Docu Centre III C7600, manufactured by Fuji Xerox Co., Ltd.) having an intermediate transfer belt. On recording paper (OK Top Coat + paper, manufactured by Oji Paper Co., Ltd.) in an environment of 25°C and 50% RH, at a fixing temperature of 190°C and a fixing pressure of 4.0 kg / cm 2 a solid image with a toner loading of 4.5 mg / cm 2 was formed. Regarding the obtained solid image, the glossiness was evaluated visually under the lighting for color observation (natural daylight lighting) in accordance with JIS K5600-4-3:1999 "General Test Methods for Paints - Part 4: Visual Characteristics of Paint Films - Section 3: Visual Comparison of Colors". The evaluation was performed by evaluating the graininess (the effect of shiny gloss) and the optical effect (the change in hue depending on the viewing angle), and was classified into the following stages. 5: The graininess and the optical effect are in harmony. 4: There is slightly graininess and optical effect, which is within the acceptable range for practical use. 3: It is a normal feeling and within the acceptable range for practical use. 2: It has a slightly blurred feeling, but it is within the acceptable range for practical use. 1: There is no graininess or optical effect at all, and it is not suitable for practical use.

[0156]

Table 1

[0157] From the above results, it can be seen that the toner of this example suppresses toner penetration compared to the toner of the comparative example.

Explanation of Signs

[0158] 1Y, 1M, 1C, 1K Photoconductor (an example of an image holding member) 2Y, 2M, 2C, 2K Charging roll (an example of a charging means) 3 Exposure device (an example of an electrostatic charge image forming means) 3Y, 3M, 3C, 3K Laser beam 4Y, 4M, 4C, 4K Developing device (an example of a developing means) 5Y, 5M, 5C, 5K Primary transfer roll (an example of a primary transfer means) 6Y, 6M, 6C, 6K Photoconductor cleaning device (an example of a cleaning means) 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 Driving roll 24 Support roll 26 Secondary transfer roll (an example of secondary transfer means) 30 Intermediate transfer body cleaning device 107 Photoconductor (an example of an image holding body) 108 Charging roll (an example of charging means) 109 Exposure device (an example of electrostatic charge image forming means) 111 Developing device (an example of developing means) 112 Transfer device (an example of transfer means) 113 Photoconductor cleaning device (an example of cleaning means) 115 Fixing device (an example of fixing means) 116 Mounting rail 117 Housing 118 Opening for exposure 200 Process cartridge 300 Recording paper (an example of a recording medium) P Recording paper (an example of a recording medium)

Claims

1. A toner for electrostatic charge image development, comprising toner particles containing a binder resin, a release agent, a bright pigment, and an aminocarboxylic acid compound.

2. The toner for electrostatic charge image development according to claim 1, wherein the number of carboxy groups of the aminocarboxylic acid compound is 3 or more and 5 or less, and the number of amino groups of the aminocarboxylic acid compound is 2 or more and 4 or less.

3. The toner for electrostatic charge image development according to claim 2, wherein the number of carboxy groups of the aminocarboxylic acid compound is 4 or more and 5 or less.

4. The toner for electrostatic charge image development according to claim 2 or claim 3, wherein the number of amino groups of the aminocarboxylic acid compound is 2 or more and 3 or less.

5. The toner for electrostatic charge image development according to any one of claims 1 to 4, wherein the content of the aminocarboxylic acid compound is 1 ppm or more and 100 ppm or less based on the total amount of the toner for electrostatic charge image development.

6. The toner for electrostatic charge image development according to claim 5, wherein the content of the aminocarboxylic acid compound is 30 ppm or more and 60 ppm or less based on the total amount of the toner for electrostatic charge image development.

7. The toner for electrostatic charge image development according to any one of claims 1 to 6, wherein the pH of the aminocarboxylic acid compound is 4 or more and 12 or less.

8. The toner for electrostatic charge image development according to claim 7, wherein the pH of the aminocarboxylic acid compound is 5 or more and 8 or less.

9. The toner for electrostatic charge image development according to any one of claims 1 to 8, wherein the ratio C / D of the average maximum thickness C to the average equivalent circle diameter D of the toner particles is 0.01 or more and 0.50 or less.

10. The toner for electrostatic charge image development according to any one of claims 1 to 9, wherein the binder resin contains a polyester resin.

11. An electrostatic charge image developer containing the toner for electrostatic charge image development according to any one of claims 1 to 10.

12. A toner cartridge that houses the toner for electrostatic charge image development according to any one of claims 1 to 10 and is detachable from an image forming apparatus.

13. A process cartridge that houses the electrostatic charge image developer according to claim 11 and includes developing means for developing an electrostatic charge image formed on the surface of an image carrier into a toner image with the electrostatic charge image developer, and is detachable from an image forming apparatus.

14. An image carrier, charging means for charging the surface of the image carrier, Electrostatic charge image forming means for forming an electrostatic charge image on the surface of the charged image carrier; Developing means for accommodating the electrostatic charge developer according to claim 11 and developing the electrostatic charge image formed on the surface of the image carrier as a toner image with the electrostatic charge developer; An intermediate transfer member onto which the toner image is transferred on the surface; Primary transfer means for primarily transferring the toner image formed on the surface of the image carrier onto the surface of the intermediate transfer member; Secondary transfer means for secondarily transferring the toner image transferred onto the surface of the intermediate transfer member onto the surface of a recording medium; Cleaning means having a cleaning blade for cleaning the surface of the intermediate transfer member; Fixing means for fixing the toner image secondarily transferred onto the surface of the recording medium; An image forming apparatus comprising the above.

15. An image carrier; Charging means for charging the surface of the image carrier; Electrostatic charge image forming means for forming an electrostatic charge image on the surface of the charged image carrier; Developing means for accommodating the electrostatic charge developer according to claim 11 and developing the electrostatic charge image formed on the surface of the image carrier as a toner image with the electrostatic charge developer; Transfer means for transferring the toner image formed on the surface of the image carrier onto the surface of a recording medium; Cleaning means having a cleaning blade for cleaning the surface of the image carrier; Fixing means for fixing the toner image transferred onto the surface of the recording medium; An image forming apparatus comprising the above.

Images