Toner for developing electrostatic images, electrostatic image developer, toner cartridge, process cartridge, image forming apparatus, and image forming method

Abstract

To provide an electrostatic image developing toner which as a superior property to suppress gloss unevenness after temperature of an image has risen.SOLUTION: An electrostatic image developing toner is provided, comprising toner particles containing a binder resin including a crystalline resin, and resin particles having a loss coefficient tanδS(30) of 1 or greater at 30°C and tanδS(50) of less than 1 at 50°C.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] Patent Document 1 states that "a binder resin containing at least an amorphous resin and a binder resin having an elastic modulus of 10 at 30°C 4 Pa or more 10 6 The elastic modulus at 100°C is 10 Pa or less. 4 Pa or more 10 6 and a toner for developing electrostatic images, which contains resin particles having a surface tension of 0.001 Pa or less. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-052714 Summary of the Invention [Problem to be solved by the invention]

[0004] The object of the present invention is to provide a toner for developing electrostatic images, which comprises a binder resin containing a crystalline resin and toner particles containing resin particles, in the case where the resin particles have a loss coefficient tanδS(30) at 30°C of less than 1, or a loss coefficient tanδS(50) at 50°C of 1 or more, or a toner loading amount of 13.5 g / m 2 The present invention provides a toner for developing electrostatic images, which forms a 25 mm x 25 mm square image, and is excellent in suppressing gloss unevenness after the temperature of the image is increased, compared to when the rate of change in gloss of the image before and after heating the image at 50°C for 30 days is less than 0% or more than 10.0%. [Means for solving the problem]

[0005] The above problems are solved by the following means: <1> The toner includes a binder resin containing a crystalline resin and toner particles containing resin particles, The toner for developing electrostatic images, wherein the resin particles have a loss coefficient tan δS(30) of 1 or more at 30°C and a loss coefficient tan δS(50) of less than 1 at 50°C. <2> The difference between the loss factor tanδS(30) and the loss factor tanδS(50) (tanδS(30)-tanδS(50)) is 0.5 or more. <1> 2. The toner for developing electrostatic images according to claim 1. <3> The difference between the loss factor tanδS(30) and the loss factor tanδS(50) (tanδS(30)-tanδS(50)) is 0.8 or more and 3.0 or less. <2> 2. The toner for developing electrostatic images according to claim 1. <4> When the loss coefficient of the crystalline resin at 30°C is tan δC(30) and the loss coefficient of the crystalline resin at 50°C is tan δC(50), The ratio (tan δS(30) / tan δC(30)) of the loss coefficient tan δS(30) to the loss coefficient tan δC(30) is 20.0 or more and 60.0 or less, The ratio (tan δS(50) / tan δC(50)) of the loss coefficient tan δS(50) to the loss coefficient tan δC(50) is 2.0 or more and 20.0 or less. <1> ~ <3> 10. The toner for developing electrostatic images according to claim 9, wherein the toner is a toner for developing electrostatic images. <5> The ratio (S / C) of the content C of the crystalline resin to the content S of the resin particles is 0.05 or more and 5.0 or less on a mass basis. <1> ~ <4> 10. The toner for developing electrostatic images according to claim 9, wherein the toner is a toner for developing electrostatic images. <6> The content of the resin particles in the entire toner for developing electrostatic images is 1% by mass or more and 30% by mass or less. <1> ~ <5> 10. The toner for developing electrostatic images according to claim 9, wherein the toner is a toner for developing electrostatic images. <7> The resin particles are crosslinked resin particles. <1> ~ <6> 10. The toner for developing electrostatic images according to claim 9, wherein the toner is a toner for developing electrostatic images. <8> The crosslinked resin particles are styrene-(meth)acrylic copolymer resin particles. <7> 2. The toner for developing electrostatic images according to claim 1. <9> The crystalline resin includes a crystalline polyester resin. <8> 2. The toner for developing electrostatic images according to claim 1. <10> the difference between the solubility parameter SP value (S) of the resin particles and the solubility parameter SP value (R) of the binder resin (SP value (S) - SP value (R)) is -1.0 or more and 1.0 or less; <1> ~ <9> 10. The toner for developing electrostatic images according to claim 9, wherein the toner is a toner for developing electrostatic images. <11> the difference between the solubility parameter SP value (S) of the resin particles and the solubility parameter SP value (C) of the crystalline resin (SP value (S) - SP value (C)) is 0 or more and 2.0 or less; <1> ~ <10> 10. The toner for developing electrostatic images according to claim 9, wherein the toner is a toner for developing electrostatic images. <12> The dispersion diameter of the resin particles is 50 nm or more and 500 nm or less. <1> ~ <11> 10. The toner for developing electrostatic images according to claim 9, wherein the toner is a toner for developing electrostatic images. <13> a binder resin containing a crystalline resin; Resin particles; The toner particles include Toner amount: 13.5g / m 2 A toner for developing electrostatic images, which forms a 25 mm x 25 mm square image, and which exhibits a change in gloss of the image of 0% or more and 10.0% or less before and after heating the image at 50°C for 30 days. <14> The aforementioned <1> ~ <13> 10. An electrostatic image developer comprising the toner for developing electrostatic images according to any one of claims 1 to 9. <15> The aforementioned <1> ~ <13> The toner for developing electrostatic images according to any one of the above items is contained in the container. A toner cartridge that is detachably attached to an image forming device. <16> The aforementioned <14> and a developing means for developing an electrostatic image formed on the surface of an image carrier into a toner image by using the electrostatic image developer, A process cartridge is detachably mounted in an image forming apparatus. <17> an image carrier; a charging means for charging the surface of the image carrier; an electrostatic image forming means for forming an electrostatic image on the charged surface of the image carrier; The aforementioned <14> a developing means for developing the electrostatic image formed on the surface of the image carrier into a toner image by using the electrostatic 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; a fixing means for fixing the toner image transferred onto the surface of the recording medium; An image forming apparatus comprising: <18> a charging step of charging the surface of the image carrier; an electrostatic image forming step of forming an electrostatic image on the charged surface of the image carrier; The aforementioned <14> a developing step of developing the electrostatic image formed on the surface of the image carrier as a toner image using the electrostatic image developer according to claim 1; a transfer step of transferring the toner image formed on the surface of the image carrier to the surface of a recording medium; a fixing step of fixing the toner image transferred onto the surface of the recording medium; An image forming method comprising the steps of: [Effects of the Invention]

[0006] <1> According to the invention, there is provided a toner for developing electrostatic images, which has a binder resin containing a crystalline resin and toner particles containing resin particles, and which is excellent in suppressing uneven gloss after the temperature of an image increases, compared to when the resin particles have a loss coefficient tanδS(30) at 30°C of less than 1 or a loss coefficient tanδS(50) at 50°C of 1 or more. <2> According to the invention, a toner for developing electrostatic images is provided that is excellent in suppressing uneven gloss after the temperature of the image rises, compared to when the difference between the loss coefficient tan δS(30) and the loss coefficient tan δS(50) (tan δS(30) - tan δS(50)) is less than 0.5. <3> According to the invention, there is provided a toner for developing electrostatic images that is excellent in suppressing uneven gloss after the temperature of the image rises, compared to when the difference between the loss coefficient tan δS(30) and the loss coefficient tan δS(50) (tan δS(30) - tan δS(50)) is less than 0.8 or exceeds 3.0. <4> According to the invention related to (1), there is provided a toner for developing electrostatic images which is excellent in suppressing uneven gloss after the temperature of the image rises, compared to when the ratio of the loss coefficient tan δS(30) to the loss coefficient tan δC(30) (tan δS(30) / tan δC(30)) is less than 20.0 or exceeds 60.0, or when the ratio of the loss coefficient tan δS(50) to the loss coefficient tan δC(50) (tan δS(50) / tan δC(50)) is less than 2.0 or exceeds 20.0. <5> According to the invention, a toner for developing electrostatic images is provided that is excellent in suppressing uneven gloss after the temperature of the image rises, compared to when the ratio (S / C) of the crystalline resin content C to the resin particle content S is less than 0.05 or exceeds 5.0 by mass.

[0007] <6> According to the invention, a toner for developing electrostatic images is provided that is excellent in suppressing uneven gloss after the temperature of the image rises, compared to when the content of resin particles relative to the entire toner for developing electrostatic images is less than 1% by mass or more than 30% by mass. <7> or <8> According to the present invention, a toner for developing electrostatic images is provided that is excellent in suppressing uneven gloss after the temperature of the image rises, compared to when the resin particles are specific resin particles containing a polyester resin and an acrylic resin. <9> According to the invention, a toner for developing electrostatic images is provided which is superior in suppressing uneven gloss after the temperature of the image rises, compared to when the crystalline resin contains a crystalline polyether resin. <10> According to the invention, there is provided a toner for developing electrostatic images which is excellent in suppressing uneven gloss after the temperature of the image increases, compared to when the difference between the solubility parameter SP value (S) of the resin particles and the solubility parameter SP value (R) of the binder resin (SP value (S) - SP value (R)) is less than -1.0 or exceeds 1.0.

[0008] <11> According to the invention, there is provided a toner for developing electrostatic images that is excellent in suppressing uneven gloss after the temperature of the image increases, compared to when the difference between the solubility parameter SP value (S) of the resin particles and the solubility parameter SP value (C) of the crystalline resin (SP value (S) - SP value (C)) is less than 0 or exceeds 2.0. <12> According to the invention, a toner for developing electrostatic images is provided which is excellent in suppressing uneven gloss after the temperature of the image rises, compared to when the dispersed diameter of the resin particles is less than 50 nm or more than 500 nm. <13> According to the invention, in a toner for developing an electrostatic image having a binder resin containing a crystalline resin and toner particles containing resin particles, a toner loading amount of 13.5 g / m 2 The present invention provides a toner for developing electrostatic images, which forms a 25 mm x 25 mm square image, and has excellent suppression of gloss unevenness after the temperature of the image is increased, compared to when the absolute value of the gloss difference between the image before and after heating at 50°C for 30 days is less than 0% or exceeds 10.0%. <14> , <15> , <16> , <17> , or <18> According to the invention, in a toner for developing electrostatic images, the toner has a binder resin containing a crystalline resin and toner particles containing resin particles, and the resin particles have a loss coefficient tanδS(30) at 30°C of less than 1, or a loss coefficient tanδS(50) at 50°C of 1 or more, or a toner loading amount of 13.5 g / m 2 The present invention provides an electrostatic image developer, a toner cartridge, a process cartridge, an image forming apparatus, or an image forming method, which includes a toner for developing electrostatic images, which forms a 25 mm x 25 mm square image, and which is excellent in suppressing gloss unevenness after the temperature of the image rises, compared to when the absolute value of the gloss difference of the image before and after heating the image at 50°C for 30 days is less than 0% or exceeds 10.0%. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an embodiment of the present invention. [Figure 2]1 is a schematic diagram illustrating an example of a process cartridge that is detachably mounted to an image forming apparatus according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described. These descriptions and examples are intended to illustrate the embodiment and are not intended to limit the scope of the invention. In the present specification, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range. In addition, in the present specification, the upper or lower limit of a numerical range may be replaced with a value shown in the examples. In this specification, (meth)acrylic means both acrylic and methacrylic.

[0011] Each component may contain multiple types of the corresponding substance. When referring to the amount of each component in a composition, if there are multiple substances corresponding to each component in the composition, the amount refers to the total amount of those multiple substances present in the composition, unless otherwise specified.

[0012] <Toner for developing electrostatic images> The toner for developing electrostatic images (hereinafter also referred to as "toner") according to the first embodiment has a binder resin containing a crystalline resin, and toner particles containing resin particles. The resin particles have a loss factor tan δS(30) of 1 or more at 30°C, and a loss factor tan δS(50) of 1 or less at 50°C. Hereinafter, resin particles having a loss factor tan δS(30) at 30°C of 1 or more and a loss factor tan δS(50) at 50°C of less than 1 will also be referred to as specific resin particles.

[0013] The toner according to the first embodiment has the above-described structure, and is therefore excellent in suppressing uneven glossiness of an image after the temperature of the image has risen. The reason for this is presumed to be as follows.

[0014] In an image obtained using a toner having a binder resin containing a crystalline resin and toner particles containing resin particles, the crystalline resin contained in the image is likely to ooze out onto the image surface when the temperature of the image rises. The crystalline resin that has oozed out onto the image surface is likely to smooth the image surface by being re-dissolved in the binder resin, which can easily cause uneven gloss in the image.

[0015] In the toner according to the first embodiment, the resin particles have a loss coefficient tanδS(30) at 30°C of 1 or more. This indicates that the resin particles have viscous properties at 30°C, and the molecules in the resin particles are in molecular motion. Similarly, in the case of crystalline resins, the molecules are in molecular motion around 30°C, so that the affinity between the resin particles and the crystalline resin is likely to be high. Therefore, the resin particles and the crystalline resin are likely to be in close proximity in the image, which further enhances the effect of suppressing the smoothing of the image surface, as described below. The loss factor tanδS(50) of the resin particles at 50°C is less than 1. This indicates that the resin particles have the properties of an elastic body at 50°C. Under 50°C conditions, the crystalline resin contained in the image oozes out onto the image surface and is likely to re-dissolve with the binder resin. Under these temperature conditions, the elasticity of the resin particles makes it easier to suppress the dissolution of the crystalline resin and the binder resin, and therefore makes it easier to suppress the smoothing of the image surface.

[0016] From the above, it is considered that the toner according to the first embodiment is excellent in suppressing uneven gloss after the temperature of the image rises.

[0017] The toner according to the second embodiment contains toner particles that include a binder resin containing a crystalline resin and resin particles. In addition, the toner load is 13.5 g / m 2 A square image of 25 mm x 25 mm is formed, and the gloss of the image changes by 0% or more and 10.0% or less before and after heating the image at 50°C for 30 days.

[0018] The toner according to the second embodiment, due to the above-described constitution, is excellent in suppressing uneven glossiness of an image after the temperature of the image has risen. The reason for this is presumed to be as follows.

[0019] Toner amount: 13.5g / m 2 A 25mm x 25mm square image is formed, and the image is heated at 50°C for 30 days. The absolute value of the difference in gloss of the image before and after heating is 0% or more and 10.0% or less. This indicates that the difference in gloss of the image before and after the temperature rises is small. Therefore, the gloss of the image is less likely to increase even after the temperature rises.

[0020] From the above, it is considered that the toner according to the second embodiment is excellent in suppressing uneven gloss after the temperature of the image rises.

[0021] Hereinafter, a toner corresponding to either the toner according to the first or second embodiment will be described in detail, however, an example of the toner of the present invention may be a toner corresponding to either the toner according to the first or second embodiment.

[0022] (toner particles) The toner particles contain a binder resin containing a crystalline resin, and resin particles, and may also contain a colorant, a release agent, and other additives as required.

[0023] -Binder resin- Examples of binder resins 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.), and olefins (e.g., ethylene, propylene, butadiene, etc.), and vinyl resins made of copolymers of 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, and modified rosin, mixtures of these with the vinyl resins, and 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.

[0024] In particular, the binder resin contains a crystalline resin, for example, the binder resin contains a crystalline resin and an amorphous resin. Here, the crystalline resin refers to a resin that exhibits a clear endothermic peak rather than a stepwise change in endothermic amount in differential scanning calorimetry (DSC). On the other hand, an amorphous resin is one that does not show a clear endothermic peak but only a stepwise endothermic change in thermal analysis measurement using differential scanning calorimetry (DSC), is a solid at room temperature, and becomes thermoplastic at temperatures above its glass transition temperature. Specifically, for example, a crystalline resin means a resin whose half-width of the endothermic peak when measured at a heating rate of 10°C / min is within 10°C, and an amorphous resin means a resin whose half-width exceeds 10°C or a resin in which no clear endothermic peak is observed.

[0025] The crystalline resin will now be described. Examples of the crystalline resin include known crystalline resins such as crystalline polyester resins and crystalline vinyl resins (e.g., polyalkylene resins, long-chain alkyl (meth)acrylate resins, etc.) Among these, crystalline polyester resins are preferred in terms of the mechanical strength and low-temperature fixability of the toner.

[0026] Crystalline polyester resin The crystalline polyester resin may be, for example, a polycondensate of a polycarboxylic acid and a polyhydric alcohol. Note that, as the crystalline polyester resin, a commercially available product or a synthesized product may be used. Here, the crystalline polyester resin is preferably a polycondensate using a polymerizable monomer having a linear aliphatic group rather than a polymerizable monomer having an aromatic group, since it easily forms a crystalline structure.

[0027] Examples of polycarboxylic acids include aliphatic dicarboxylic acids (e.g., oxalic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, etc.), aromatic dicarboxylic acids (e.g., dibasic acids such as phthalic acid, isophthalic acid, terephthalic acid, and naphthalene-2,6-dicarboxylic acid), anhydrides thereof, and lower alkyl esters thereof (e.g., having 1 to 5 carbon atoms). The polycarboxylic acid may be a tricarboxylic or higher carboxylic acid having a crosslinked or branched structure in combination with a dicarboxylic acid. Examples of the tricarboxylic acid include aromatic carboxylic acids (e.g., 1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, etc.), anhydrides thereof, and lower alkyl esters thereof (e.g., having 1 to 5 carbon atoms). As the polycarboxylic acid, a dicarboxylic acid having a sulfonic acid group and a dicarboxylic acid having an ethylenic double bond may be used in combination with these dicarboxylic acids. The polycarboxylic acids may be used alone or in combination of two or more.

[0028] Examples of polyhydric alcohols include aliphatic diols (for example, straight-chain aliphatic diols having 7 to 20 carbon atoms in the main chain). Examples of aliphatic diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, and 1,14-eicosanedecanediol. Among these, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferred as aliphatic diols. The polyhydric alcohol may be a trihydric or higher alcohol having a crosslinked or branched structure, such as glycerin, trimethylolethane, trimethylolpropane, or pentaerythritol, in combination with the diol. The polyhydric alcohols may be used alone or in combination of two or more.

[0029] Here, the polyhydric alcohol preferably has an aliphatic diol content of 80 mol % or more, and more preferably 90 mol % or more.

[0030] The melting temperature of the crystalline polyester resin is preferably 50°C or higher and 120°C or lower, more preferably 55°C or higher and 110°C or lower, and even more preferably 60°C or higher and 100°C or lower. The melting temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC) using the "melting peak temperature" described in the method for determining the melting temperature in JIS K7121-1987 "Method for measuring transition temperatures of plastics."

[0031] The weight average molecular weight (Mw) of the crystalline polyester resin is preferably 6,000 or more and 50,000 or less.

[0032] The crystalline polyester resin can be obtained by a known manufacturing method, for example, in the same manner as the amorphous polyester.

[0033] The amorphous resin will be described. Examples of amorphous resins include known amorphous resins such as amorphous polyester resins, amorphous vinyl resins (e.g., styrene-acrylic resins), epoxy resins, polycarbonate resins, polyurethane resins, etc. Among these, amorphous polyester resins and amorphous vinyl resins (particularly styrene-acrylic resins) are preferred, and amorphous polyester resins are more preferred.

[0034] Amorphous polyester resin Examples of the amorphous polyester resin include a condensation polymer of a polycarboxylic acid and a polyhydric alcohol. Note that, as the amorphous polyester resin, a commercially available product or a synthesized product may be used.

[0035] Examples of polycarboxylic acids include aliphatic dicarboxylic acids (such as oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, alkenylsuccinic acid, adipic acid, and sebacic acid), alicyclic dicarboxylic acids (such as cyclohexanedicarboxylic acid), aromatic dicarboxylic acids (such as terephthalic acid, isophthalic acid, phthalic acid, and naphthalenedicarboxylic acid), anhydrides thereof, and lower alkyl esters thereof (e.g., having 1 to 5 carbon atoms). Among these, aromatic dicarboxylic acids are preferred as polycarboxylic acids. The polycarboxylic acid may be a trivalent or higher carboxylic acid having a crosslinked or branched structure in combination with a dicarboxylic acid. Examples of the trivalent or higher carboxylic acid include trimellitic acid, pyromellitic acid, anhydrides thereof, and lower alkyl esters thereof (e.g., having 1 to 5 carbon atoms). The polycarboxylic acids may be used alone or in combination of two or more.

[0036] Examples of polyhydric alcohols include aliphatic diols (e.g., ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, etc.), alicyclic diols (e.g., cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, etc.), and aromatic diols (e.g., ethylene oxide adducts of bisphenol A, propylene oxide adducts of bisphenol A, etc.). Among these, preferred polyhydric alcohols are aromatic diols and alicyclic diols, and more preferred are aromatic diols. As the polyhydric alcohol, a trihydric or higher polyhydric alcohol having a crosslinked or branched structure may be used in combination with the diol. Examples of trihydric or higher polyhydric alcohols include glycerin, trimethylolpropane, and pentaerythritol. The polyhydric alcohols may be used alone or in combination of two or more.

[0037] The glass transition temperature (Tg) of the amorphous polyester resin is preferably 50°C or higher and 80°C or lower, and more preferably 50°C or higher and 70°C or lower. The glass transition temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC), more specifically, from the "extrapolated glass transition onset temperature" described in JIS K 7121-1987 "Method for measuring transition temperatures of plastics."

[0038] The weight average molecular weight (Mw) of the amorphous polyester resin is preferably 5,000 or more and 1,000,000 or less, and more preferably 7,000 or more and 500,000 or less. The number average molecular weight (Mn) of the amorphous polyester resin is preferably 2,000 or more and 100,000 or less. The molecular weight distribution Mw / Mn of the amorphous polyester resin is preferably 1.5 or more and 100 or less, and more preferably 2 or more and 60 or less. The weight-average molecular weight and number-average molecular weight are measured by gel permeation chromatography (GPC). Molecular weight measurements by GPC are performed using a Tosoh GPC HLC-8120GPC measuring device and a Tosoh TSKgel SuperHM-M (15 cm) column in THF solvent. The weight-average molecular weight and number-average molecular weight are calculated from the measurement results using a molecular weight calibration curve prepared with monodisperse polystyrene standard samples.

[0039] The amorphous polyester resin can be obtained by a known manufacturing method, for example, by carrying out the reaction at a polymerization temperature of 180°C or higher and 230°C or lower, reducing the pressure in the reaction system as necessary, and removing water and alcohol generated during the condensation. If the raw material monomer is not soluble or compatible at the reaction temperature, a high-boiling solvent may be added as a solubilizer to dissolve it. In this case, the polycondensation reaction is carried out while distilling off the solubilizer. If a monomer with poor compatibility is present, it is advisable to first condense the poorly compatible monomer with the acid or alcohol to be polycondensed, and then polycondense the monomer with the main component.

[0040] The content of the binder resin is, for example, preferably 40% by mass to 98% by mass, more preferably 50% by mass to 97% by mass, and even more preferably 60% by mass to 95% by mass, based on the total mass of the toner particles.

[0041] The mass ratio (C / A) of the content A of the amorphous resin to the content C of the crystalline resin is preferably 3 / 97 or more and 50 / 50 or less, and more preferably 5 / 95 or more and 30 / 70 or less.

[0042] -Specific resin particles- The specific resin particles have a loss factor tan δS(30) at 30°C of 1 or more and a loss factor tan δS(50) at 50°C of less than 1.

[0043] The loss factor of the specific resin particles is a value measured using a rheometer. As a rheometer, for example, a product name "ARES-G2" manufactured by TA Instruments can be used. The procedure for measuring the loss factor tan δS(30) at 30° C. and the loss factor tan δS(50) at 50° C. will be specifically described below. The resin particles to be measured are heated to 100°C and molded to prepare a disk-shaped sample with a thickness of 1 mm and a diameter of 8 mm. The disk-shaped sample is sandwiched between parallel plates with a diameter of 8 mm, and the loss factor is measured using a rheometer under measurement conditions of a frequency of 1 Hz and a strain of 0.03% to 20%. The disk-shaped sample is then heated from 25°C to 140°C at a heating rate of 1°C / min, and the loss factor versus temperature is measured. The loss factor measured when the disc-shaped sample is at 30°C is defined as loss factor tan δS(30), and the loss factor measured when the disc-shaped sample is at 50°C is defined as loss factor tan δS(50).

[0044] The loss coefficient tan δS(30) at 30° C. of the specific resin particles is preferably 1.1 or more and 3 or less, more preferably 1.2 or more and 2.7 or less, and even more preferably 1.3 or more and 2.5 or less. The loss coefficient tan δS(50) of the specific resin particles at 50° C. is preferably 0.1 or more and 0.9 or less, more preferably 0.2 or more and 0.8 or less, and even more preferably 0.25 or more and 0.7 or less.

[0045] The difference between the loss coefficient tan δS(30) and the loss coefficient tan δS(50) (tan δS(30) - tan δS(50)) is preferably 0.5 or more, more preferably 0.8 or more and 3.0 or less, and even more preferably 1.0 or more and 2.5 or less.

[0046] By keeping the difference (tan δS(30) - tan δS(50)) within the above range, the loss coefficient of the resin particles tends to gradually decrease as the temperature of the specific resin particles increases. As a result, when the temperature of the specific resin particles is low, the specific resin particles tend to have more viscous properties, and as the temperature of the specific resin particles increases, the specific resin particles tend to have more elastic properties. This makes it easier to suppress compatibility between the crystalline resin and the binder resin, and more easily suppresses smoothing of the image surface.

[0047] The specific resin particles are preferably crosslinked resin particles. Here, the term "crosslinked resin particles" refers to resin particles that have a bridge structure between specific atoms in the polymer structure contained in the resin particles.

[0048] By using crosslinked resin particles as the specific resin particles, the specific resin particles are more likely to have a loss coefficient tanδS(50) at 50°C of less than 1. This makes it more likely that the toner for developing electrostatic images will have better suppression of uneven gloss after the temperature of the image rises.

[0049] Examples of the crosslinked resin particles include crosslinked resin particles crosslinked by ionic bonds (ionically crosslinked resin particles), crosslinked resin particles crosslinked by covalent bonds (covalently crosslinked resin particles), etc. Among these, crosslinked resin particles crosslinked by covalent bonds are preferred.

[0050] Examples of resins used in the crosslinked resin particles include polyolefin resins (polyethylene, polypropylene, etc.), styrene resins (polystyrene, α-polymethylstyrene, etc.), (meth)acrylic resins (polymethyl methacrylate, polyacrylonitrile, etc.), epoxy resins, polyurethane resins, polyurea resins, polyamide resins, polycarbonate resins, polyether resins, polyester resins, and copolymer resins thereof. These resins may be used alone or in combination of two or more types, as needed.

[0051] Of the above resins, styrene-(meth)acrylic copolymer resins are preferred as the resins used for the crosslinked resin particles. That is, the crosslinked resin particles are preferably styrene-(meth)acrylic copolymer resin particles.

[0052] When the crosslinked resin particles are styrene-(meth)acrylic copolymer resin particles, the resin particles tend to have a loss coefficient tanδS(30) at 30°C of 1 or more, and a loss coefficient tanδS(50) at 50°C of less than 1. This tends to result in a toner for developing electrostatic images that is more excellent in suppressing uneven gloss after the temperature of the image rises.

[0053] Examples of the styrene-(meth)acrylic copolymer resin include resins obtained by radical polymerization of the following styrene monomer and (meth)acrylic acid monomer.

[0054] Examples of styrene-based monomers include styrene, α-methylstyrene, vinylnaphthalene, alkyl-substituted styrenes having alkyl chains such as 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, and 4-ethylstyrene, halogen-substituted styrenes such as 2-chlorostyrene, 3-chlorostyrene, and 4-chlorostyrene, and fluorine-substituted styrenes such as 4-fluorostyrene and 2,5-difluorostyrene, etc. Among these, styrene and α-methylstyrene are preferred.

[0055] Examples of (meth)acrylic acid monomers include (meth)acrylic acid, n-methyl (meth)acrylate, n-ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, n-lauryl (meth)acrylate, n-tetradecyl (meth)acrylate, n-hexadecyl (meth)acrylate, n-octadecyl (meth)acrylate, isopropyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, isopentyl (meth)acrylate, amyl (meth)acrylate, (meth)acrylate, Examples of such acrylates include neopentyl (meth)acrylate, isohexyl (meth)acrylate, isoheptyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, phenyl (meth)acrylate, biphenyl (meth)acrylate, diphenylethyl (meth)acrylate, t-butylphenyl (meth)acrylate, terphenyl (meth)acrylate, cyclohexyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, methoxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, β-carboxyethyl (meth)acrylate, (meth)acrylonitrile, and (meth)acrylamide. Among these, n-butyl (meth)acrylate and β-carboxyethyl (meth)acrylate are preferred.

[0056] In the crosslinked resin particles, examples of crosslinking agents for crosslinking the resin include aromatic polyvinyl compounds such as divinylbenzene and divinylnaphthalene; polyvinyl esters of aromatic polycarboxylic acids such as divinyl phthalate, divinyl isophthalate, divinyl terephthalate, divinyl homophthalate, divinyl trimesate, trivinyl trimesate, divinyl naphthalenedicarboxylate, and divinyl biphenylcarboxylate; divinyl esters of nitrogen-containing aromatic compounds such as divinyl pyridinedicarboxylate; vinyl esters of unsaturated heterocyclic carboxylic acids such as vinyl pyromucate, vinyl furancarboxylate, vinyl pyrrole-2-carboxylate, and vinyl thiophenecarboxylate; and linear polyhydric alcohols such as butanediol methacrylate, hexanediol acrylate, octanediol methacrylate, decanediol acrylate, and dodecanediol methacrylate. Examples of suitable crosslinking agents include (meth)acrylic acid esters; (meth)acrylic acid esters of branched or substituted polyhydric alcohols such as neopentyl glycol dimethacrylate and 2-hydroxy-1,3-diacryloxypropane; polyethylene glycol di(meth)acrylate, polypropylene polyethylene glycol di(meth)acrylates; and polyvinyl esters of polycarboxylic acids such as divinyl succinate, divinyl fumarate, vinyl maleate, divinyl maleate, divinyl diglycolate, vinyl itaconate, divinyl itaconate, divinyl acetonedicarboxylate, divinyl glutarate, divinyl 3,3'-thiodipropionate, divinyl trans-aconitate, trivinyl trans-aconitate, divinyl adipate, divinyl pimelate, divinyl suberate, divinyl azelaate, divinyl sebacate, divinyl dodecanedioate, and divinyl brassylate. These crosslinking agents may be used singly or in combination of two or more.

[0057] The dispersion diameter of the specific resin particles is preferably 50 nm or more and 500 nm or less. By setting the dispersion diameter of the specific resin particles within the above range, the dispersibility of the specific resin particles in the toner particles is likely to be improved. By improving the dispersibility of the specific resin particles, the crystalline resin and the resin particles in the toner particles are more likely to be in close proximity to each other, which is likely to further enhance the effect of suppressing smoothing of the image surface.

[0058] The dispersion diameter of the specific resin particles is more preferably 80 nm or more and 400 nm or less, and even more preferably 100 nm or more and 300 nm or less.

[0059] The dispersed diameter of the specific resin particles is a value measured using a transmission electron microscope (TEM). As a transmission electron microscope, for example, JEM-2100plus manufactured by JEOL Ltd. can be used. The method for measuring the dispersion diameter of the specific resin particles will be specifically described below. Toner particles are cut into pieces about 0.1 μm thick using a microtome. The cross section of the toner particle is photographed at 10,000x magnification using a transmission electron microscope, and the circular equivalent diameter of 100 resin particles dispersed in the toner particle is calculated from the individual cross-sectional area, and the arithmetic average of these is taken as the dispersion diameter.

[0060] The content of the specific resin particles in the entire toner for developing electrostatic images is preferably 1% by mass or more and 30% by mass or less, more preferably 2% by mass or more and 25% by mass or less, and even more preferably 3% by mass or more and 20% by mass or less.

[0061] By making the content of the specific resin particles 1% by mass or more relative to the entire toner for developing electrostatic images, the content of the specific resin particles in the toner particles becomes sufficient, thereby enhancing the effect of suppressing compatibility between the crystalline resin and the binder resin. By setting the content of specific resin particles to 30% by mass or less relative to the entire toner for developing electrostatic images, the content of specific resin particles does not become excessively high, and the impact of the unevenness of the image surface caused by the inclusion of specific resin particles on the gloss of the image is reduced. Therefore, the toner is more likely to have excellent suppression of uneven gloss after the temperature of the image has risen.

[0062] -The relationship between binder resin and specific resin particles- Loss factor ratio of crystalline resin and specific resin particles When the loss coefficient of the crystalline resin at 30°C is tan δC(30) and the loss coefficient of the crystalline resin at 50°C is tan δC(50), it is preferable that the ratio of the loss coefficient tan δS(30) to the loss coefficient tan δC(30) (tan δS(30) / tan δC(30)) is 20.0 or more and 60.0 or less, and the ratio of the loss coefficient tan δS(50) to the loss coefficient tan δC(50) (tan δS(50) / tan δC(50)) is 2.0 or more and 20.0 or less.

[0063] By setting the ratio of the loss coefficients of the crystalline resin and the resin particles within the above range, the affinity between the crystalline resin and the specific resin particles is more likely to be improved, which makes it easier to maintain the resin particles and the crystalline resin in close proximity in the image, further enhancing the effect of suppressing smoothing of the image surface.

[0064] The ratio (tan δS(30) / tan δC(30)) is more preferably 22.0 or more and 55.0 or less, and even more preferably 25.0 or more and 50.0 or less. The ratio (tan δS(50) / tan δC(50)) is more preferably 2.5 or more and 15.0 or less, and even more preferably 3.0 or more and 10.0 or less.

[0065] The loss factor of the crystalline resin is a value measured using a rheometer. As a rheometer, for example, a product name "ARES-G2" manufactured by TA Instruments can be used. The procedure for measuring the loss factor of a crystalline resin will now be described in detail. A disk-shaped sample with a thickness of 1 mm and a diameter of 8 mm is prepared using a resin with the same composition as the crystalline resin to be measured contained in the toner particles.The loss factor of the obtained disk-shaped sample is measured using the same procedure as for the loss factor of the specific resin particles. The loss factor measured when the disc-shaped sample is at 30°C is defined as loss factor tan δC(30), and the loss factor measured when the disc-shaped sample is at 50°C is defined as loss factor tan δC(50).

[0066] The ratio (S / C) of the crystalline resin content C to the specific resin particle content S is preferably 0.05 or more and 5.0 or less by mass, more preferably 0.2 or more and 4.0 or less, and even more preferably 0.5 or more and 3.0 or less.

[0067] By setting the ratio (S / C) to 0.05 or more, the content of the specific resin particles relative to the crystalline resin becomes sufficient, and the effect of suppressing compatibility between the crystalline resin and the binder resin is enhanced. By setting the ratio (S / C) to 5.0 or less, the content of specific resin particles relative to the crystalline resin will not be excessively high, and the impact of the unevenness of the image surface caused by the inclusion of specific resin particles on the gloss of the image will be reduced. Therefore, the toner is more likely to have excellent suppression of uneven gloss after the temperature of the image has risen.

[0068] The difference between the solubility parameter SP value (S) of the specific resin particles and the solubility parameter SP value (R) of the binder resin (SP value (S) - SP value (R)) is preferably from -1.0 to 1.0.

[0069] By setting the difference (SP value (S) - SP value (R)) to be -1.0 or more and 1.0 or less, the dispersibility of the specific resin particles in the toner particles is likely to be improved. By improving the dispersibility of the specific resin particles, the crystalline resin and the resin particles in the toner particles are more likely to be in close proximity to each other, and the effect of suppressing smoothing of the image surface is likely to be further enhanced.

[0070] The difference (SP value (S) - SP value (R)) is more preferably -0.9 or more and 0.9 or less, and even more preferably -0.8 or more and 0.8 or less.

[0071] The difference between the solubility parameter SP value (S) of the specific resin particles and the solubility parameter SP value (C) of the crystalline resin (SP value (S) - SP value (C)) is preferably 0 or more and 2.0 or less.

[0072] By setting the difference (SP value (S) - SP value (C)) to be 0 or more and 2.0 or less, the affinity between the crystalline resin and the specific resin particles is more likely to be improved, so that the resin particles and the crystalline resin in the image are more likely to be maintained in close proximity, and the effect of suppressing smoothing of the image surface is more likely to be enhanced.

[0073] The difference (SP value (S) - SP value (C)) is more preferably 0 or more and 1.8 or less, and even more preferably 0 or more and 1.5 or less.

[0074] From the viewpoint of improving the suppression of gloss unevenness after the temperature of the image is increased, the solubility parameter SP value (S) of the specific resin particles is preferably 7.0 or more and 14.0 or less, more preferably 8.0 or more and 12.0 or less, and even more preferably 9.0 or more and 11.0 or less.

[0075] Here, the solubility parameter SP value (S) of the specific resin particles, the solubility parameter SP value (R) of the binder resin, and the solubility parameter SP value (C) of the crystalline resin (unit: (cal / cm 3 ) 1 / 2 ) is calculated using the Fedors method. Specifically, the SP value is calculated using the following formula: Formula: SP value = √(Ev / v) = √(ΣΔei / ΣΔvi) (where Ev: evaporation energy (cal / mol), v: molar volume (cm 3 / mol), Δei: evaporation energy of each atom or atomic group, Δvi: molar volume of each atom or atomic group) Details of this calculation method are described in Polym. Eng. Sci., vol. 14, p. 147 (1974), "Practical Polymers for Engineers" by Junji Mukai et al., p. 66 (Kodansha, 1981), Polymer Handbook (4th edition, Willey-Interscience Publication), etc., and a similar method is also applied in this embodiment. In this embodiment, the unit of the SP value is (cal / cm 3 ) 1 / 2 However, in accordance with convention, the units are omitted and the value is expressed as dimensionless.

[0076] -Coloring agent- Examples of colorants include carbon black, chrome yellow, Hansa Yellow, benzidine yellow, threne yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, Balkan orange, watch young red, permanent red, brilliant carmine 3B, brilliant carmine 6B, DuPont oil red, pyrazolone red, lithol red, rhodamine B lake, lake red C, pigment red, rose bengal, aniline blue, ultramarine blue, and the like. Examples of the dye include various pigments such as phosphorus blue, chalco oil blue, methylene blue chloride, phthalocyanine blue, pigment blue, phthalocyanine green, and malachite green oxalate, and various dyes such as acridine-based, xanthene-based, azo-based, benzoquinone-based, azine-based, anthraquinone-based, thioindigo-based, dioxazine-based, thiazine-based, azomethine-based, indigo-based, phthalocyanine-based, aniline black-based, polymethine-based, triphenylmethane-based, diphenylmethane-based, and thiazole-based dyes. The colorant may be used alone or in combination of two or more kinds.

[0077] The colorant may be surface-treated as needed, or may be used in combination with a dispersant. Furthermore, a plurality of colorants may be used in combination.

[0078] The content of the colorant is, for example, preferably 1% by mass or more and 30% by mass or less, and more preferably 3% by mass or more and 15% by mass or less, based on the total mass of the toner particles.

[0079] -Mold release agent- Examples of release agents include hydrocarbon waxes, natural waxes such as carnauba wax, rice wax, and candelilla wax, synthetic or mineral / petroleum waxes such as montan wax, and ester waxes such as fatty acid esters and montanic acid esters, but are not limited thereto.

[0080] The melting temperature of the release agent is preferably 50°C or higher and 110°C or lower, and more preferably 60°C or higher and 100°C or lower. The melting temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC) by using the "melting peak temperature" as described in the method for determining the melting temperature in JIS K 7121-1987 "Method for measuring transition temperatures of plastics."

[0081] The content of the release agent is, for example, preferably 1% by mass or more and 20% by mass or less, and more preferably 3% by mass or more and 15% by mass or less, based on the total mass of the toner particles.

[0082] -Other additives- Examples of other additives include well-known additives such as magnetic materials, charge control agents, inorganic powders, etc. These additives are contained in the toner particles as internal additives.

[0083] -Characteristics of toner particles, etc.- The toner particles may be toner particles of a single layer structure, or may be toner particles of a so-called core-shell structure composed of a core part (core particle) and a coating layer (shell layer) that coats the core part. Here, the toner particles having a core-shell structure may be composed of, for example, a core containing a binder resin and, if necessary, other additives such as a colorant and a release agent, and a coating layer containing the binder resin.

[0084] The volume average particle size (D50v) of the toner particles is preferably 2 μm or more and 10 μm or less, and more preferably 3 μm or more and 8 μm or less.

[0085] The various average particle sizes and particle size distribution indices of the toner particles are measured using a Coulter Multisizer III (manufactured by Beckman Coulter), and the electrolyte is measured using an ISOTON-II (manufactured by Beckman Coulter). For the measurement, 0.5 mg to 50 mg of the sample to be measured is added to 2 ml of a 5% aqueous solution of a surfactant (preferably sodium alkylbenzene sulfonate) as a dispersant, and this is then added to 100 ml to 150 ml of the electrolyte. The electrolyte solution containing the suspended sample is dispersed for 1 minute using an ultrasonic disperser, and the particle size distribution of particles with a particle size range of 2 μm to 60 μm is measured using a Coulter Multisizer II with an aperture diameter of 100 μm. The number of particles sampled is 50,000. Based on the particle size distribution measured, cumulative distributions of volume and number are drawn for each divided particle size range (channel) from the smallest diameter side, and the particle size at 16% of the cumulative total is defined as the volume particle size D16v, the number particle size D16p, the particle size at 50% of the cumulative total as the volume average particle size D50v, the cumulative number average particle size D50p, and the particle size at 84% of the cumulative total as the volume particle size D84v and the number particle size D84p. Using these, the volumetric particle size distribution index (GSDv) is (D84v / D16v) 1 / 2 , the number particle size distribution index (GSDp) is (D84p / D16p) 1 / 2 It is calculated as:

[0086] The average circularity of the toner particles is preferably 0.94 or more and 1.00 or less, and more preferably 0.95 or more and 0.99 or less.

[0087] The average circularity of toner particles is calculated by (circular equivalent perimeter) / (perimeter) [(perimeter of a circle having the same projected area as the particle image) / (perimeter of the particle projected image)]. Specifically, this value is measured by the following method. First, the toner particles to be measured are sucked and collected, forming a flat flow, and a still image of the particles is captured by instantaneously emitting a strobe light, and the particle image is analyzed using a flow-type particle image analyzer (FPIA-3000 manufactured by Spectris, Inc.). The number of samples to be sampled when calculating the average circularity is 4,500. When the toner contains external additives, the toner (developer) to be measured is dispersed in water containing a surfactant, and then ultrasonic treatment is performed to obtain toner particles from which the external additives have been removed.

[0088] (external additives) The toner may contain an external additive, if necessary. Examples of external additives include inorganic particles such as SiO2, TiO2, Al2O3, CuO, ZnO, SnO2, CeO2, Fe2O3, MgO, BaO, CaO, KO, Na2O, ZrO2, CaO·SiO2, KO·(TiO2)n, Al2O3·2SiO2, CaCO3, MgCO3, BaSO4, and MgSO4.

[0089] The surfaces of inorganic particles as external additives are preferably subjected to a hydrophobic treatment. The hydrophobic treatment is carried out, for example, by immersing the inorganic particles in a hydrophobic treatment agent. The hydrophobic treatment agent is not particularly limited, and examples thereof include silane coupling agents, silicone oils, titanate coupling agents, and aluminum coupling agents. These may be used alone or in combination of two or more. The amount of the hydrophobic treatment agent is usually, for example, 1 part by mass or more and 60 parts by mass or less per 100 parts by mass of the inorganic particles.

[0090] Examples of external additives include resin particles (resin particles such as polystyrene, polymethyl methacrylate (PMMA), and melamine resin), cleaning agents (for example, metal salts of higher fatty acids such as zinc stearate, and particles of fluorine-based polymers).

[0091] The amount of the external additive added is, for example, preferably 0.01% by mass or more and 10% by mass or less, and more preferably 0.01% by mass or more and 8.0% by mass or less, based on the toner particles.

[0092] (Toner characteristics) The toner according to this embodiment has a toner loading of 13.5 g / m 2 A square image of 25 mm x 25 mm is formed, and the gloss of the image changes by 0% or more and 10.0% or less before and after heating the image at 50°C for 30 days.

[0093] From the viewpoint of further suppressing smoothing of the image surface, the change rate of the gloss of the image before and after heating the image at 50°C for 30 days is preferably 0% or more and 9.0% or less, more preferably 0% or more and 8.0% or less, and even more preferably 0% or more and 5.0% or less.

[0094] The measurement of the rate of change in gloss will be specifically described below. Coated paper (Oji Paper Co., Ltd. Mirror Coat Platinum Paper, US basis weight 256 g / m 2 ) 10 sheets, toner load 13.5g / m 2 A 25 mm×25 mm square image is formed using an image forming device (for example, ApeosPort C4570 manufactured by Fujifilm Business Innovation Co., Ltd.). The 60-degree gloss of each image was measured using a gloss meter at the four corners (top right, bottom right, top left, and bottom left) and center of the image, and the arithmetic average of the 50 measurements was taken to determine the "gloss of the image before heating." Next, the paper on which the image is formed is placed in a constant temperature and humidity chamber with an internal temperature of 50° C. and a humidity of 20%, and the image is heated for 30 days. After heating, the 60-degree gloss of each image was measured using a gloss meter at the four corners (top right, bottom right, top left, and bottom left) and center of the image, and the arithmetic average of the 50 measured values ​​was determined as the "gloss of the image after heating." The gloss change rate calculated from the difference between the "gloss of the image before heating" and the "gloss of the image after heating" ({"gloss of the image before heating" - "gloss of the image after heating"} / gloss of the image before heating x 100) is the change rate of the gloss of the image before and after heating. Here, as the gloss meter, for example, a portable gloss meter (BYK Gardner Micro Trigloss, manufactured by Toyo Seiki Seisakusho Co., Ltd.) can be used.

[0095] (Toner manufacturing method) Next, a method for producing the toner according to this embodiment will be described. The toner according to the exemplary embodiment can be obtained by producing toner particles and then externally adding an external additive to the toner particles, if necessary.

[0096] The toner particles may be produced by any of a dry production method (for example, a kneading and pulverization method) and a wet production method (for example, an aggregation and coalescence method, a suspension polymerization method, a dissolution and suspension method). The method for producing the toner particles is not particularly limited, and any well-known production method may be used. Among these, it is preferable to obtain toner particles by the aggregation and coalescence method.

[0097] Specifically, for example, when toner particles are produced by the aggregation and coalescence method, Toner particles are manufactured through the following steps: a step of preparing a resin particle dispersion in which resin particles that will become the binder resin are dispersed, and a specific resin particle dispersion in which the specific resin particles will become the specific resin particles (resin particle dispersion preparation step); a step of aggregating resin particles (and other particles, if necessary) in the resin particle dispersion (in a dispersion after mixing other particle dispersions, if necessary) to form aggregated particles (aggregated particle formation step); and a step of heating the aggregated particle dispersion in which the aggregated particles are dispersed, fusing and coalescing the aggregated particles to form toner particles (fusion and coalescence step).

[0098] Each step will be described in detail below. In the following description, a method for obtaining toner particles containing a colorant and a release agent will be described, but the colorant and the release agent are used as needed. Of course, additives other than the colorant and the release agent may also be used.

[0099] -Resin particle dispersion preparation process- First, a resin particle dispersion in which resin particles serving as a binder resin are dispersed, as well as a colorant particle dispersion in which colorant particles are dispersed and a release agent particle dispersion in which release agent particles are dispersed are prepared.

[0100] Here, the resin particle dispersion liquid is prepared, for example, by dispersing resin particles in a dispersion medium using a surfactant.

[0101] Examples of the dispersion medium used in the resin particle dispersion include aqueous media. Examples of aqueous media include water such as distilled water and ion-exchanged water, alcohols, etc. These may be used alone or in combination of two or more.

[0102] Examples of surfactants include anionic surfactants such as sulfate ester salts, sulfonate salts, phosphate esters, and soaps; cationic surfactants such as amine salts and quaternary ammonium salts; and nonionic surfactants such as polyethylene glycols, alkylphenol ethylene oxide adducts, and polyhydric alcohols. Among these, anionic surfactants and cationic surfactants are particularly preferred. Nonionic surfactants may be used in combination with anionic surfactants or cationic surfactants. The surfactants may be used alone or in combination of two or more.

[0103] In the resin particle dispersion, resin particles can be dispersed in a dispersion medium by a general dispersion method such as a rotary shear homogenizer, a ball mill having a medium, a sand mill, a dyno mill, etc. Depending on the type of resin particles, the resin particles may be dispersed in the resin particle dispersion by, for example, a phase inversion emulsification method. The phase inversion emulsification method involves dissolving the resin to be dispersed in a hydrophobic organic solvent in which the resin is soluble, adding a base to the organic continuous phase (O phase) to neutralize it, and then adding an aqueous medium (W phase), thereby converting the resin from W / O to O / W (so-called phase inversion) and forming a discontinuous phase, and dispersing the resin in particulate form in the aqueous medium.

[0104] The volume average particle size of the resin particles dispersed in the resin particle dispersion is, for example, preferably from 0.01 μm to 1 μm, more preferably from 0.08 μm to 0.8 μm, and even more preferably from 0.1 μm to 0.6 μm. The volume average particle size of the resin particles is measured using a particle size distribution obtained by measurement with a laser wave particle size distribution analyzer (for example, LS-13 320 manufactured by Beckman Coulter, Inc.), and the cumulative distribution for the volume of the divided particle size range (channel) is calculated from the small particle size side, and the particle size at which the cumulative 50% of all particles is measured is defined as the volume average particle size D50v. The volume average particle sizes of particles in other dispersions are also measured in the same way.

[0105] The content of resin particles contained in the resin particle dispersion is, for example, preferably from 5% by mass to 50% by mass, and more preferably from 10% by mass to 40% by mass.

[0106] Note that, for example, a colorant particle dispersion and a release agent particle dispersion are also prepared in the same manner as the resin particle dispersion. That is, the volume average particle size, dispersion medium, dispersion method, and particle content of the particles in the resin particle dispersion are the same for the colorant particles dispersed in the colorant particle dispersion and the release agent particles dispersed in the release agent particle dispersion.

[0107] Preparation of specific resin particle dispersion The specific resin particle dispersion may be prepared by any known method, such as emulsion polymerization, melt-kneading using a Banbury mixer or kneader, suspension polymerization, or spray drying, with emulsion polymerization being preferred.

[0108] From the viewpoint of keeping the loss factor within a preferred range, it is preferable to use a styrene-based monomer and a (meth)acrylic acid-based monomer as the monomers and polymerize them in the presence of a crosslinking agent. In addition, in the production of the specific resin particles, it is preferable to carry out emulsion polymerization multiple times. The method for producing the specific resin particles will be described in more detail below.

[0109] The method for preparing the specific resin particle dispersion liquid is as follows: a step of obtaining an emulsion containing a monomer, a crosslinking agent, a surfactant, and water (emulsion preparation step); a step of adding a polymerization initiator to the emulsion and heating the emulsion to polymerize the monomers (first emulsion polymerization step); It is preferable to include a step (second emulsion polymerization step) of adding an emulsion containing a monomer to the reaction solution after the first emulsion polymerization step and heating the mixture to polymerize the monomer.

[0110] Here, when a styrene-based monomer and a (meth)acrylic acid-based monomer are used as monomers, the molecular chain state or the crosslinked state of the resin can be changed by adjusting the ratio of the styrene-based monomer among the monomers contained in the reaction solution in the first emulsion polymerization step and the ratio of the styrene-based monomer among the monomers added in the second emulsion polymerization step, taking into account the difference in reactivity. As described above, adjusting the monomer ratio tends to result in a high glass transition temperature inside the specific resin particles, while a low glass transition temperature is likely to occur near the surface of the specific resin particles. In addition to adjusting the monomer ratio, the molecular chain state or the crosslinked state of the resin can be changed by considering the reactivity of the monomers and adjusting the polymerization temperature, the amount and method of polymerization initiator addition, the dripping speed of the emulsion, the amount of crosslinking agent added, and other factors. This tends to result in resin particles with a loss factor tanδS(30) of 1 or greater at 30°C and a loss factor tanδS(50) of less than 1 at 50°C.

[0111] -Emulsion preparation process- This is a step of obtaining an emulsion containing a monomer, a crosslinking agent, a surfactant, and water. It is preferable to obtain an emulsion by emulsifying the monomer, crosslinking agent, surfactant, and water using an emulsifier. Examples of emulsifiers include rotary mixers equipped with propeller-, anchor-, paddle-, or turbine-type stirring blades, static mixers such as static mixers, rotor-stator emulsifiers such as homogenizers and Clearmix, mill-type emulsifiers equipped with a grinding function, high-pressure emulsifiers such as Manton-Gaulin pressure emulsifiers, high-pressure nozzle-type emulsifiers that generate cavitation under high pressure, high-pressure collision-type emulsifiers such as microfluidizers that apply shear force by causing liquids to collide with each other under high pressure, ultrasonic emulsifiers that generate cavitation using ultrasound, and membrane emulsifiers that emulsify uniformly through fine pores.

[0112] As the monomer, it is preferable to use a styrene-based monomer and a (meth)acrylic acid-based monomer. As the crosslinking agent, those already mentioned above are applicable.

[0113] Examples of surfactants include anionic surfactants such as sulfate ester salts, sulfonate salts, phosphate esters, and soaps; cationic surfactants such as amine salts and quaternary ammonium salts; and nonionic surfactants such as polyethylene glycols, alkylphenol ethylene oxide adducts, and polyhydric alcohols. Nonionic surfactants may be used in combination with anionic surfactants or cationic surfactants. Among these, anionic surfactants are preferred. The surfactants may be used alone or in combination of two or more.

[0114] The emulsion may contain a chain transfer agent. There are no particular limitations on the chain transfer agent, but a compound having a thiol component can be used. Specifically, alkyl mercaptans such as hexyl mercaptan, heptyl mercaptan, octyl mercaptan, nonyl mercaptan, decyl mercaptan, and dodecyl mercaptan are preferred.

[0115] -First emulsion polymerization process- This is a process in which a polymerization initiator is added to the emulsion and heated to polymerize the monomers. Here, when carrying out the polymerization, it is preferable to stir the emulsion (reaction solution) containing the polymerization initiator with a stirrer. Examples of the agitator include rotary agitators equipped with propeller-type, anchor-type, paddle-type, or turbine-type agitator blades. As the polymerization initiator, ammonium persulfate is preferably used.

[0116] -Second emulsion polymerization process- This is a step in which an emulsion containing a monomer is added to the reaction solution after the first emulsion polymerization step, and the mixture is heated to polymerize the monomer. During the polymerization, it is preferable to stir the reaction solution in the same manner as in the first emulsion polymerization step. The emulsion containing the monomer is preferably obtained by emulsifying the monomer, surfactant, and water using an emulsifier, for example.

[0117] -Agglomerated particle formation process- Next, the colorant particle dispersion, the release agent particle dispersion, and the specific resin particle dispersion are mixed together with the resin particle dispersion. Then, in the mixed dispersion, the resin particles, colorant particles, release agent particles, and specific resin particles are hetero-aggregated to form aggregated particles containing the resin particles, colorant particles, release agent particles, and specific resin particles, which have a diameter close to the diameter of the target toner particles.

[0118] Specifically, for example, an aggregating agent is added to the mixed dispersion, and the pH of the mixed dispersion is adjusted to be acidic (for example, a pH of 2 or more and 5 or less), and a dispersion stabilizer is added as necessary. After that, the mixed dispersion is heated to the glass transition temperature of the resin particles (specifically, for example, a temperature of the glass transition temperature of the resin particles -30°C or more and the glass transition temperature -10°C or less), and the particles dispersed in the mixed dispersion are aggregated to form aggregated particles. In the aggregate particle formation step, for example, the above-mentioned aggregating agent may be added to the mixed dispersion at room temperature (e.g., 25°C) while stirring with a rotary shear homogenizer, the pH of the mixed dispersion may be adjusted to an acidic value (e.g., pH 2 or more and 5 or less), and a dispersion stabilizer may be added as necessary, followed by the heating.

[0119] Examples of the flocculant include a surfactant having a polarity opposite to that of the surfactant used as the dispersant added to the mixed dispersion, an inorganic metal salt, and a divalent or higher metal complex. In particular, when a metal complex is used as the flocculant, the amount of surfactant used can be reduced and the charging characteristics can be improved. If necessary, an additive that forms a complex or a similar bond with the metal ions of the flocculant may be used, and a chelating agent is preferably used as this additive.

[0120] Examples of inorganic metal salts include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate, as well as inorganic metal salt polymers such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. The chelating agent may be a water-soluble chelating agent, such as hydroxycarboxylic acid (e.g., tartaric acid, citric acid, gluconic acid), iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA), etc. The amount of the chelating agent added is, for example, preferably 0.01 parts by mass or more and 5.0 parts by mass or less, and more preferably 0.1 parts by mass or more and less than 3.0 parts by mass, per 100 parts by mass of the resin particles.

[0121] -Fusion / unification process- Next, the aggregated particle dispersion liquid in which the aggregated particles are dispersed is heated, for example, to a temperature equal to or higher than the glass transition temperature of the resin particles (for example, a temperature 10 to 30°C higher than the glass transition temperature of the resin particles), to fuse and coalesce the aggregated particles and form toner particles.

[0122] Through the above steps, toner particles are obtained. After obtaining an aggregated particle dispersion in which aggregated particles are dispersed, the toner particles may be produced through the following steps: a step of further mixing the aggregated particle dispersion with a resin particle dispersion in which resin particles are dispersed, and aggregating the aggregated particles so that further resin particles adhere to the surfaces of the aggregated particles to form second aggregated particles; and a step of heating the second aggregated particle dispersion in which the second aggregated particles are dispersed to fuse and coalesce the second aggregated particles to form toner particles having a core / shell structure.

[0123] After the fusion and coalescence process, the toner particles formed in the solution are subjected to a known washing process, a solid-liquid separation process, and a drying process to obtain dry toner particles. In the washing step, it is preferable to carry out sufficient replacement washing with ion-exchanged water from the viewpoint of electrostatic chargeability. Furthermore, the solid-liquid separation step is not particularly limited, but from the viewpoint of productivity, it is preferable to carry out suction filtration, pressure filtration, etc. Furthermore, in the drying step, there is no particular limitation on the method, but from the viewpoint of productivity, it is preferable to carry out freeze drying, flash drying, fluidized drying, vibration-type fluidized drying, etc.

[0124] The toner according to this embodiment is produced by, for example, adding an external additive to the obtained dry toner particles and mixing them. The mixing can be carried out using, for example, a V blender, a Henschel mixer, a Loedige mixer, or the like. Furthermore, if necessary, coarse particles may be removed from the toner using a vibrating sieve, an air sieve, or the like.

[0125] <Electrostatic image developer> The electrostatic image developer according to this embodiment contains at least the toner according to this embodiment. The electrostatic image developer according to this embodiment may be a one-component developer containing only the toner according to this embodiment, or may be a two-component developer containing the toner mixed with a carrier.

[0126] The carrier is not particularly limited, and examples thereof include known carriers, such as coated carriers in which the surface of a core material made of magnetic powder is coated with a coating resin, magnetic powder dispersion carriers in which magnetic powder is dispersed and blended in a matrix resin, and resin-impregnated carriers in which porous magnetic powder is impregnated with a resin. The magnetic powder dispersion type carrier and the resin impregnated type carrier may be a carrier in which the constituent particles of the carrier are used as a core material and are coated with a coating resin.

[0127] Examples of magnetic powder include magnetic metals such as iron, nickel, and cobalt, and magnetic oxides such as ferrite and magnetite.

[0128] Examples of coating resins and matrix resins include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic acid ester copolymer, straight silicone resins containing organosiloxane bonds or modified products thereof, fluororesins, polyesters, polycarbonates, phenolic resins, and epoxy resins. The coating resin and the matrix resin may contain other additives such as conductive particles. Examples of conductive particles include particles of metals such as gold, silver, and copper, carbon black, titanium oxide, zinc oxide, tin oxide, barium sulfate, aluminum borate, and potassium titanate.

[0129] Here, the method of coating the surface of the core material with a coating resin includes a method of coating with a solution for forming a coating layer, in which the coating resin and, if necessary, various additives are dissolved in an appropriate solvent. The solvent is not particularly limited and may be selected taking into consideration the coating resin to be used, its applicability, etc. Specific resin coating methods include an immersion method in which the core material is immersed in a solution for forming a coating layer, a spray method in which the solution for forming a coating layer is sprayed onto the surface of the core material, a fluidized bed method in which the solution for forming a coating layer is sprayed onto the core material while it is suspended in flowing air, and a kneader coater method in which the core material of the carrier and the solution for forming a coating layer are mixed in a kneader coater and the solvent is removed.

[0130] In the two-component developer, the mixing ratio (mass ratio) of toner to carrier is preferably toner:carrier=1:100 to 30:100, and more preferably 3:100 to 20:100.

[0131] <Image forming device / image forming method> An image forming apparatus and an image forming method according to this embodiment will be described. The image forming apparatus according to the present embodiment includes an image carrier, a charging unit that charges the surface of the image carrier, an electrostatic image forming unit that forms an electrostatic image on the surface of the charged image carrier, a developing unit that contains an electrostatic image developer and develops the electrostatic image formed on the surface of the image carrier as a toner image using the electrostatic image developer, a transfer unit that transfers the toner image formed on the surface of the image carrier to the surface of a recording medium, and a fixing unit that fixes the toner image transferred to the surface of the recording medium. The electrostatic image developer according to the present embodiment is used as the electrostatic image developer.

[0132] The image forming apparatus according to this embodiment carries out an image forming method (the image forming method according to this embodiment) that includes a charging step of charging the surface of an image carrier, an electrostatic image forming step of forming an electrostatic image on the surface of the charged image carrier, a developing step of developing the electrostatic image formed on the surface of the image carrier as a toner image using the electrostatic image developer according to this 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.

[0133] The image forming apparatus according to the present embodiment may be any of known image forming apparatuses, such as a direct transfer type apparatus that directly transfers a toner image formed on the surface of an image carrier to a recording medium; an intermediate transfer type apparatus that primarily transfers a toner image formed on the surface of an image carrier to the surface of an intermediate transfer medium, and then secondarily transfers the toner image transferred to the surface of the intermediate transfer medium to the surface of a recording medium; an apparatus equipped with a cleaning means that cleans the surface of the image carrier after the transfer of the toner image but before charging; and an apparatus equipped with a discharging means that irradiates the surface of the image carrier with discharging light to discharge it after the transfer of the toner image but before charging. In the case of an intermediate transfer type device, the transfer means is configured to have, for example, an intermediate transfer body onto whose surface a toner image is transferred, a primary transfer means which primarily transfers the toner image formed on the surface of the image carrier onto the surface of the intermediate transfer body, and a secondary transfer means which secondarily transfers the toner image transferred onto the surface of the intermediate transfer body onto the surface of the recording medium.

[0134] In the image forming apparatus according to the present embodiment, for example, a portion including the developing means may have a cartridge structure (process cartridge) that is detachably attached to the image forming apparatus. As the process cartridge, for example, a process cartridge equipped with developing means that accommodates the electrostatic image developer according to the present embodiment is preferably used.

[0135] An example of an image forming apparatus according to the present embodiment will be described below, but the present invention is not limited to this. Note that only the main parts shown in the drawings will be described, and descriptions of other parts will be omitted.

[0136] FIG. 1 is a schematic diagram showing the configuration of an image forming apparatus according to this embodiment. The image forming apparatus shown in Figure 1 includes first through fourth electrophotographic image forming units 10Y, 10M, 10C, and 10K (image forming means) that output images in the colors yellow (Y), magenta (M), cyan (C), and black (K) based on color-separated image data. These image forming units (hereinafter sometimes simply referred to as "units") 10Y, 10M, 10C, and 10K are arranged side by side horizontally spaced a predetermined distance apart from one another. Note that these units 10Y, 10M, 10C, and 10K may also be process cartridges that are detachable from the image forming apparatus.

[0137] Above each of the units 10Y, 10M, 10C, and 10K in the drawing, an intermediate transfer belt 20 serving as an intermediate transfer body extends through each unit. The intermediate transfer belt 20 is wound around a drive roll 22 and a support roll 24 that are spaced apart from each other and arranged from left to right in the drawing, and is configured to run in a direction from the first unit 10Y to the fourth unit 10K. A force is applied to the support roll 24 in a direction away from the drive roll 22 by a spring or the like (not shown), thereby applying tension to the intermediate transfer belt 20 wound around them. In addition, an intermediate transfer body cleaning device 30 is provided on the image carrier side of the intermediate transfer belt 20, facing the drive roll 22. In addition, the developing devices (developing means) 4Y, 4M, 4C, and 4K of the units 10Y, 10M, 10C, and 10K are supplied with toner including four colors of toner, yellow, magenta, cyan, and black, contained in toner cartridges 8Y, 8M, 8C, and 8K, respectively.

[0138] Since the first to fourth units 10Y, 10M, 10C, and 10K have the same configuration, the first unit 10Y, which forms a yellow image and is disposed upstream in the direction of travel of the intermediate transfer belt, will be described here as a representative. Note that parts equivalent to those of the first unit 10Y are given reference numerals with magenta (M), cyan (C), and black (K) instead of yellow (Y), and descriptions of the second to fourth units 10M, 10C, and 10K will be omitted.

[0139] The first unit 10Y has a photoreceptor 1Y that acts as an image carrier. Around the photoreceptor 1Y, there are arranged in this order: a charging roll (an example of a charging means) 2Y that charges the surface of the photoreceptor 1Y to a predetermined potential; an exposure device (an example of an electrostatic image forming means) 3 that exposes the charged surface to a laser beam 3Y based on a color-separated image signal to form an electrostatic image; a developing device (an example of a developing means) 4Y that supplies charged toner to the electrostatic image to develop it; a primary transfer roll 5Y (an example of a primary transfer means) that transfers the developed toner image onto an intermediate transfer belt 20; and a photoreceptor cleaning device (an example of a cleaning means) 6Y that removes toner remaining on the surface of the photoreceptor 1Y after the primary transfer. The primary transfer roll 5Y is disposed inside the intermediate transfer belt 20 and is positioned opposite the photoreceptor 1Y. Furthermore, a bias power supply (not shown) that applies a primary transfer bias is connected to each of the 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).

[0140] The operation of forming a yellow image in first unit 10Y will be described below. First, prior to operation, the surface of the photosensitive member 1Y is charged to a potential of −600V to −800V by the charging roll 2Y. The photoconductor 1Y has conductivity (for example, volume resistivity at 20°C: 1×10 -6 The photosensitive layer is formed by laminating a photosensitive layer on a substrate with a resistivity of Ωcm or less. This photosensitive layer normally has a high resistance (the resistance of ordinary resins), but when irradiated with a laser beam 3Y, the resistivity of the irradiated portion changes. Therefore, a laser beam 3Y is output to the charged surface of the photosensitive element 1Y via an exposure device 3 in accordance with image data for yellow sent from a control unit (not shown). The laser beam 3Y is irradiated onto the photosensitive layer on the surface of the photosensitive element 1Y, thereby forming an electrostatic charge image of a yellow image pattern on the surface of the photosensitive element 1Y.

[0141] An electrostatic image is an image formed on the surface of the photosensitive element 1Y by charging it; the laser beam 3Y reduces the resistivity of the irradiated portion of the photosensitive layer, causing the charged charges on the surface of the photosensitive element 1Y to flow, while the charges remain in the portions not irradiated by the laser beam 3Y, forming a so-called negative latent image. The electrostatic image formed on the photoreceptor 1Y is rotated to a predetermined development position as the photoreceptor 1Y travels. At this development position, the electrostatic image on the photoreceptor 1Y is made visible as a toner image (developed image) by the developing device 4Y.

[0142] The developing device 4Y contains an electrostatic image developer containing, for example, at least yellow toner and a carrier. The yellow toner is frictionally charged by being stirred inside the developing device 4Y, and is held on a developer roll (an example of a developer holder) with a charge of the same polarity (negative polarity) as the charge on the photoreceptor 1Y. 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 with the yellow toner. The photoreceptor 1Y on which the yellow toner image has been formed continues to travel at a predetermined speed, and the toner image developed on the photoreceptor 1Y is transported to a predetermined primary transfer position.

[0143] When the yellow toner image on the photoreceptor 1Y is transported to the primary transfer, a primary transfer bias is applied to the primary transfer roll 5Y, and an electrostatic force from the photoreceptor 1Y to the primary transfer roll 5Y acts on the toner image, causing the toner image on the photoreceptor 1Y to be transferred onto the intermediate transfer belt 20. The transfer bias applied at this time has a (+) polarity opposite to the (-) polarity of the toner, and in the first unit 10Y, for example, 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 collected by the photoreceptor cleaning device 6Y.

[0144] Furthermore, the primary transfer bias applied to the primary transfer rolls 5M, 5C, and 5K of the second unit 10M and subsequent units 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 by the first unit 10Y is conveyed sequentially through the second to fourth units 10M, 10C, and 10K, and the toner images of each color are transferred onto the intermediate transfer belt 20 in a superimposed manner.

[0145] The intermediate transfer belt 20, onto which the four-color toner images have been multiplex-transferred through the first to fourth units, reaches a secondary transfer section composed of the intermediate transfer belt 20, a support roll 24 in contact with the inner surface of the intermediate transfer belt, and a secondary transfer roll (an example of a secondary transfer means) 26 arranged on the image bearing surface side of the intermediate transfer belt 20. Meanwhile, recording paper (an example of a recording medium) P is fed via a supply mechanism into the gap between the secondary transfer roll 26 and the intermediate transfer belt 20 at a predetermined timing, and a secondary transfer bias is applied to the support roll 24. The transfer bias applied at this time has a negative polarity, the same as the negative polarity of the toner. Electrostatic force from the intermediate transfer belt 20 toward the recording paper P acts on the toner image, transferring the toner image on the intermediate transfer belt 20 onto the recording paper P. The secondary transfer bias at this time is determined according to resistance detected by resistance detection means (not shown) that detects resistance in the secondary transfer section, and is voltage-controlled.

[0146] Thereafter, the recording paper P is sent to the pressure contact portion (nip portion) of a pair of fixing rolls in a fixing device (an example of fixing means) 28, where the toner image is fixed onto the recording paper P, forming a fixed image.

[0147] Examples of the recording paper P onto which the toner image is transferred include plain paper used in electrophotographic copying machines, printers, etc. In addition to the recording paper P, examples of the recording medium include overhead projector sheets and the like. 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 in which the surface of plain paper is coated with resin or the like, or art paper for printing, is preferably used.

[0148] The recording paper P on which the color image has been fixed is conveyed toward the discharge section, and the series of color image forming operations is completed.

[0149] <Process cartridges / toner cartridges> The process cartridge according to this embodiment will be described. The process cartridge according to this embodiment is a process cartridge that is detachably attached to an image forming apparatus and that contains the electrostatic image developer according to this embodiment and is equipped with a developing means that develops an electrostatic image formed on the surface of an image carrier using the electrostatic image developer into a toner image.

[0150] The process cartridge according to this embodiment is not limited to the above configuration, but may also be configured to include a developing device and, if necessary, at least one other means selected from an image carrier, a charging means, an electrostatic image forming means, and a transfer means.

[0151] An example of a process cartridge according to the present embodiment will be described below, but the present invention is not limited to this. Note that only the main parts shown in the drawings will be described, and descriptions of other parts will be omitted.

[0152] FIG. 2 is a schematic diagram showing the configuration of the process cartridge according to the present embodiment. The process cartridge 200 shown in FIG. 2 is configured to integrally combine and hold a photosensitive member 107 (an example of an image carrier), a charging roll 108 (an example of a charging means) provided around the photosensitive member 107, a developing device 111 (an example of a developing means), and a photosensitive member cleaning device 113 (an example of a cleaning means), which are held by a housing 117 provided with, for example, mounting rails 116 and an opening 118 for exposure, and is made into a cartridge. In FIG. 2, 109 denotes an exposure device (an example of an electrostatic image forming means), 112 denotes a transfer device (an example of a transfer means), 115 denotes a fixing device (an example of a fixing means), and 300 denotes recording paper (an example of a recording medium).

[0153] Next, the toner cartridge according to this embodiment will be described. The toner cartridge according to the present embodiment is a toner cartridge that contains the toner according to the present embodiment and is detachably attached to an image forming apparatus. The toner cartridge contains replenishment toner to be supplied to a developing unit provided in the image forming apparatus.

[0154] 1 is an image forming apparatus having a configuration in which toner cartridges 8Y, 8M, 8C, and 8K can be attached and detached, and developing devices 4Y, 4M, 4C, and 4K are connected to the toner cartridges corresponding to each developing device (color) by toner supply pipes (not shown). When the toner stored in a toner cartridge runs low, the toner cartridge is replaced. [Example]

[0155] Examples will be described below, but the present invention is not limited to these examples. In the following description, unless otherwise specified, all "parts" and "%" are by mass.

[0156] <Preparation of Amorphous Resin Particle Dispersion> Terephthalic acid: 100 parts by mole Bisphenol A ethylene oxide 2 mole adduct: 20 mole parts Bisphenol A propylene oxide 2 mole adduct: 80 mole parts The above materials were charged into a reaction vessel equipped with a stirrer, a nitrogen inlet tube, a temperature sensor, and a rectification column, the temperature was raised to 190°C over 1 hour, and 1.2 parts of dibutyltin oxide was added per 100 parts of the above materials. The temperature was raised to 240°C over 6 hours while distilling off the produced water, and the dehydration condensation reaction was continued for 3 hours while maintaining the temperature at 240°C, after which the reaction product was cooled.

[0157] The reaction product was transferred in a molten state to a Cavitron CD1010 (manufactured by Eurotech) at a rate of 100 g per minute. Simultaneously, a 0.37% by mass aqueous ammonia solution was heated to 120°C in a heat exchanger and transferred to the Cavitron CD1010 at a rate of 0.1 L per minute. The Cavitron CD1010 was operated at a rotor speed of 60 Hz and a pressure of 5 kg / cm2 to obtain a resin particle dispersion containing resin particles with a volume average particle size of 160 nm. Ion-exchanged water was added to the resin particle dispersion to adjust the solid content to 30% by mass, yielding an amorphous resin particle dispersion.

[0158] <Preparation of Crystalline Resin Particle Dispersion 1> 1,10-dodecanedioic acid: 225 parts by mass 1,9-nonanediol: 174 parts by mass The above materials were charged into a reaction vessel equipped with a stirrer, nitrogen inlet tube, temperature sensor, and distillation column. The temperature was raised to 160°C over 1 hour, and 0.8 parts by mass of dibutyltin oxide was added. The temperature was raised to 180°C over 6 hours while distilling off the produced water, and the dehydration condensation reaction was continued for 5 hours while maintaining 180°C. The temperature was then gradually raised to 230°C under reduced pressure (3 kPa), and stirring was continued for 2 hours while maintaining 230°C. The reaction product was then cooled. After cooling, solid-liquid separation was performed, and the solid was dried to obtain a crystalline polyester resin.

[0159] Crystalline polyester resin: 100 parts Methyl ethyl ketone: 40 parts Isopropyl alcohol: 30 parts 10% ammonia solution: 6 parts The above materials were added to a 3-liter jacketed reactor (Tokyo Rikakikai Co., Ltd.: BJ-30N) equipped with a condenser, thermometer, water dripper, and anchor blade. The resin was dissolved by stirring and mixing at 100 rpm while maintaining the temperature at 80°C in a water-circulating thermostatic bath. The water-circulating thermostatic bath was then set to 50°C, and a total of 400 parts of ion-exchanged water maintained at 50°C was added dropwise at a rate of 7 parts by mass / min to induce phase inversion, yielding an emulsion. 576 parts by mass of the resulting emulsion and 500 parts by mass of ion-exchanged water were placed in a 2-liter recovery flask and placed in an evaporator (Tokyo Rikakikai Co., Ltd.) equipped with a vacuum control unit via a trap bulb. The recovery flask was heated in a 60°C hot water bath while rotating, and the pressure was reduced to 7 kPa, taking care to avoid bumping, to remove the solvent. When the amount of solvent recovered reached 750 parts by mass, the pressure was returned to normal, and the recovery flask was water-cooled to obtain a dispersion. The volume average particle size D50v of the resin particles in this dispersion was 130 nm. Ion-exchanged water was then added to obtain crystalline resin particle dispersion 1 with a solid content of 30% by mass.

[0160] <Preparation of Crystalline Resin Particle Dispersion 2> Crystalline resin particle dispersion 2 was obtained in the same manner as in the above <Preparation of crystalline resin particle dispersion 1>, except that a crystalline polyester resin was obtained by changing the procedure after adding dibutyltin oxide in the above <Preparation of crystalline resin particle dispersion 1> as described in "Changes" below.

[0161] Changes After adding 0.8 parts by mass of dibutyltin oxide, the temperature was raised to 200°C over 6 hours while distilling off the generated water, and the dehydration condensation reaction was continued for 8 hours while maintaining 200°C. The temperature was then gradually raised to 230°C under reduced pressure (3 kPa), and stirring was continued for 2 hours while maintaining 230°C. The reaction product was then cooled. After cooling, solid-liquid separation was performed, and the solid was dried to obtain a crystalline polyester resin.

[0162] <Preparation of Crystalline Resin Particle Dispersion 3> Crystalline resin particle dispersion 3 was obtained in the same manner as in <Preparation of crystalline resin particle dispersion 1> above, except that the materials added to the reaction vessel during the preparation of the crystalline polyester resin in <Preparation of crystalline resin particle dispersion 1> above were 1,10-dodecanedioic acid and 1,9-nonanediol, and 100 parts by mass of terephthalic acid.

[0163] <Preparation of Crystalline Resin Particle Dispersion 4> 1-Octadecene oxide: 242 parts by mass 1,10-dodecanediol: 17 parts by mass The above materials were charged into a reaction vessel equipped with a stirrer, nitrogen inlet tube, temperature sensor, and distillation column, and heated to 150°C under a nitrogen stream for 4 hours. 0.6 parts by mass of potassium tert-butoxide was added, and the reaction was continued for an additional 3 hours. After cooling, the resulting resin was recrystallized twice with isopropyl alcohol to obtain crystalline resin particle dispersion 4. Note that crystalline resin particle dispersion 4 is a crystalline resin particle dispersion containing a crystalline polyether resin.

[0164] <Preparation of Crystalline Resin Particle Dispersion 5> Sebacic acid: 111 parts Terephthalic acid: 75 parts 1,6-Hexanediol: 118 parts The above materials were charged into a reaction vessel equipped with a stirrer, a nitrogen inlet tube, a temperature sensor, and a distillation column, and the temperature was raised to 160°C over 1 hour. 0.8 parts of dibutyltin oxide was then added, and the reaction was carried out for 12 hours under a nitrogen stream. After cooling, the mixture was recrystallized twice with isopropyl alcohol to obtain crystalline resin dispersion 5.

[0165] <Preparation of Crystalline Resin Particle Dispersion 6> Crystalline resin particle dispersion 6 was obtained in the same manner as in <Preparation of crystalline resin particle dispersion 5> above, except that the amount of sebacic acid charged to the reaction vessel was changed to 101 parts and the amount of terephthalic acid was changed to 83 parts.

[0166] <Preparation of Crystalline Resin Particle Dispersion 7> 1,12-dodecanedicarboxylic acid: 225 parts by mass 1,9-nonanediol: 174 parts by mass The above materials were charged into a reaction vessel equipped with a stirrer, nitrogen inlet tube, temperature sensor, and distillation column, and the temperature was raised to 160°C over 1 hour. 0.8 parts of dibutyltin oxide was then added, and the reaction was carried out for 12 hours under a nitrogen stream. After cooling, the mixture was recrystallized twice with isopropyl alcohol to obtain crystalline resin dispersion 7.

[0167] <Preparation of Crystalline Resin Particle Dispersion 8> Crystalline resin particle dispersion 8 was obtained in the same manner as in the above <Preparation of crystalline resin particle dispersion 1>, except that the dehydration condensation reaction time was changed to 10 hours.

[0168] <Preparation of specific resin particle dispersion 1> (Preparation of Emulsion 1-1) Styrene: 40 parts n-Butyl acrylate: 60 parts Divinylbenzene: 2.0 parts The above materials were placed in a mixing vessel equipped with a stirrer and stirred. A mixed solution of 1.5 parts of an anionic surfactant (Dowfax 2a1 manufactured by The Dow Chemical Company) and 60 parts of ion-exchanged water was added to the mixing vessel and stirred to prepare emulsion 1-1.

[0169] (Preparation of emulsion 1-2) Styrene: 600 parts n-Butyl acrylate: 400 parts Divinylbenzene: 20.0 parts The above materials were placed in a mixing vessel equipped with a stirrer and stirred. A mixed solution of 15 parts of an anionic surfactant (Dowfax 2a1 manufactured by The Dow Chemical Company) and 2,000 parts of ion-exchanged water was added to the mixing vessel and stirred to prepare emulsion 1-2.

[0170] (Preparation of specific resin particle dispersion 1) In a reaction vessel equipped with a stirrer and a nitrogen inlet tube, 2.0 parts of an anionic surfactant (Dowfax manufactured by The Dow Chemical Company) and 90 parts of ion-exchanged water were added and stirred. The entire amount of Emulsion 1-1 was added, and then 10 parts of 10% by mass of ammonium persulfate were added. The atmosphere inside the reaction vessel was replaced with nitrogen, and the reaction solution was heated in an oil bath while being stirred until the temperature of the reaction solution (referred to as the first reaction solution temperature) reached 60° C. Emulsion polymerization was carried out by stirring for 2 hours while maintaining the reaction solution temperature. After that, the mixture was held for 1 hour, and 1 part of ammonium persulfate was added. 1,000 parts of emulsion 1-2 were added to a reaction vessel, and the reaction solution was heated in an oil bath while stirring until the temperature of the reaction solution reached 75°C. Subsequently, emulsion 1-2 was added, and the total amount of emulsion 1-2 added was half the amount of the prepared emulsion 1-2 (i.e., 1,510 parts in the preparation of specific resin particle dispersion 1). The temperature of the reaction solution was raised to 90°C, and emulsion polymerization was carried out by stirring for 3 hours while maintaining the reaction solution temperature, and then cooled to room temperature. Ion-exchanged water was added to obtain specific resin particle dispersion 1 with a solids concentration of 35% by mass.

[0171] <Preparation of specific resin particle dispersion 2> Specific resin particle dispersion liquid 2 was prepared using the same procedure as specific resin particle dispersion liquid 1, except that emulsion 1-1 was changed to emulsion 2-1 prepared using the procedure described below, and emulsion 1-2 was changed to emulsion 2-2 prepared using the procedure described below.

[0172] (Preparation of Emulsion 2-1) Styrene: 30 parts n-Butyl acrylate: 70 parts Divinylbenzene: 2.0 parts The above materials were placed in a mixing vessel equipped with a stirrer and stirred. A mixed solution of 1.5 parts of anionic surfactant (Dowfax, manufactured by The Dow Chemical Company) and 60 parts of ion-exchanged water was added to the mixing vessel and stirred to prepare emulsion 2-1.

[0173] (Preparation of Emulsion 2-2) Styrene: 300 parts n-Butyl acrylate: 700 parts Divinylbenzene: 20.0 parts The above materials were placed in a mixing vessel equipped with a stirrer and stirred. A mixed solution of 15 parts of an anionic surfactant (Dowfax manufactured by The Dow Chemical Company) and 600 parts of ion-exchanged water was added to the mixing vessel and stirred to prepare emulsion 2-2.

[0174] <Preparation of specific resin particle dispersion 3> Specific resin particle dispersion liquid 3 was prepared using the same procedure as specific resin particle dispersion liquid 1, except that emulsion 1-1 was changed to emulsion 3-1 prepared using the procedure described below, and emulsion 1-2 was changed to emulsion 3-2 prepared using the procedure described below.

[0175] (Preparation of Emulsion 3-1) Styrene: 40 parts n-Butyl acrylate: 60 parts Divinylbenzene: 1.6 parts The above materials were placed in a mixing vessel equipped with a stirrer and stirred. A mixed solution of 1.5 parts of an anionic surfactant (Dowfax, manufactured by The Dow Chemical Company) and 60 parts of ion-exchanged water was added to the mixing vessel and stirred to prepare emulsion 3-1.

[0176] (Preparation of emulsion 3-2) Styrene: 600 parts n-Butyl acrylate: 400 parts Diphenylbenzene: 16.0 parts The above materials were placed in a mixing vessel equipped with a stirrer and stirred. A mixed solution of 15 parts of anionic surfactant (Dowfax manufactured by The Dow Chemical Company) and 600 parts of ion-exchanged water was added to the mixing vessel and stirred to prepare emulsion 3-2.

[0177] <Preparation of specific resin particle dispersion 4> (Preparation of Emulsion 4-1) Styrene: 40 parts n-Butyl acrylate: 60 parts Divinylbenzene: 2.0 parts The above materials were placed in a mixing vessel equipped with a stirrer and stirred. A mixed solution of 1.5 parts of an anionic surfactant (Dowfax, manufactured by The Dow Chemical Company) and 60 parts of ion-exchanged water was added to the mixing vessel and stirred to prepare emulsion 4-1.

[0178] (Preparation of Emulsion 4-2) Styrene: 600 parts n-Butyl acrylate: 400 parts Diphenylbenzene: 20.0 parts The above materials were placed in a mixing vessel equipped with a stirrer and stirred. A mixed solution of 15 parts of an anionic surfactant (Dowfax manufactured by The Dow Chemical Company) and 600 parts of ion-exchanged water was added to the mixing vessel and stirred to prepare emulsion 4-2.

[0179] (Preparation of specific resin particle dispersion 4) A reaction vessel equipped with a stirrer and a nitrogen inlet tube was charged with 15.0 parts of an anionic surfactant (Dowfax, manufactured by The Dow Chemical Company) and 90 parts of ion-exchanged water, followed by stirring. The entire amount of Emulsion 4-1 was added, followed by the addition of 10 parts of 10% by mass of ammonium persulfate. The atmosphere inside the reaction vessel was replaced with nitrogen, and the reaction solution was heated in an oil bath while being stirred until the temperature of the reaction solution reached 75° C. Emulsion polymerization was carried out by stirring for 2 hours while maintaining the reaction solution temperature. Subsequently, 1,000 parts of emulsion 4-2 was added to the reaction vessel, and the reaction solution was heated in an oil bath with stirring until the temperature of the reaction solution reached 75°C. The reaction solution was stirred for 4 hours while maintaining the temperature, and then cooled to room temperature. Ion-exchanged water was added to obtain specific resin particle dispersion 4 with a solids concentration of 35% by mass.

[0180] <Preparation of specific resin particle dispersion 5> Specific resin particle dispersion liquid 5 was prepared using the same procedure as specific resin particle dispersion liquid 4, except that emulsion 4-1 was changed to emulsion 5-1 prepared using the procedure described below, and emulsion 4-2 was changed to emulsion 5-2 prepared using the procedure described below.

[0181] (Preparation of Emulsion 5-1) Styrene: 40 parts n-Butyl acrylate: 60 parts Divinylbenzene: 1.5 parts The above materials were placed in a mixing vessel equipped with a stirrer and stirred. A mixed solution of 1.5 parts of an anionic surfactant (Dowfax manufactured by The Dow Chemical Company) and 60 parts of ion-exchanged water was added to the mixing vessel and stirred to prepare emulsion 5-1.

[0182] (Preparation of Emulsion 5-2) Styrene: 600 parts n-Butyl acrylate: 400 parts Divinylbenzene: 15.0 parts The above materials were placed in a mixing vessel equipped with a stirrer and stirred. A mixed solution of 15 parts of an anionic surfactant (Dowfax manufactured by The Dow Chemical Company) and 600 parts of ion-exchanged water was added to the mixing vessel and stirred to prepare emulsion 5-2.

[0183] (Preparation of specific resin particle dispersion 5) A reaction vessel equipped with a stirrer and a nitrogen inlet tube was charged with 15.0 parts of an anionic surfactant (Dowfax, manufactured by The Dow Chemical Company) and 90 parts of ion-exchanged water, followed by stirring. The entire amount of emulsion 5-1 was added, followed by the addition of 10 parts of 10% by mass of ammonium persulfate. The atmosphere inside the reaction vessel was replaced with nitrogen, and the reaction solution was heated in an oil bath while being stirred until the temperature of the reaction solution reached 75° C. Emulsion polymerization was carried out by stirring for 2 hours while maintaining the reaction solution temperature. Subsequently, 1,000 parts of emulsion 5-2 was added to the reaction vessel, and the reaction solution was heated in an oil bath with stirring until the temperature of the reaction solution reached 60°C. The reaction solution was stirred for 4 hours while maintaining the temperature, and then cooled to room temperature. Ion-exchanged water was added to obtain specific resin particle dispersion 5 with a solids concentration of 35% by mass.

[0184] <Preparation of specific resin particle dispersion 6> Specific resin dispersion 6 was obtained in the same manner as in <Preparation of specific resin dispersion 1> above, except that in the above (Preparation of emulsion 1-1), the amounts of styrene, n-butyl acrylate, and divinylbenzene charged to the mixing vessel were changed to 30 parts, 70 parts, and 1.8 parts, respectively; in the above (Preparation of emulsion 1-2), the amounts of styrene, n-butyl acrylate, and divinylbenzene charged to the mixing vessel were changed to 300 parts, 700 parts, and 18 parts, respectively; and in the above (Preparation of emulsion 1-2), the stirring time after adding the anionic surfactant and ion-exchanged water was changed to 4 hours.

[0185] <Preparation of specific resin particle dispersion 7> Specific resin dispersion 7 was obtained in the same manner as in <Preparation of specific resin dispersion 1> above, except that in the above (Preparation of emulsion 1-1), the amounts of styrene, n-butyl acrylate, and divinylbenzene charged to the mixing vessel were changed to 35 parts, 65 parts, and 1.8 parts, respectively; in the above (Preparation of emulsion 1-2), the amounts of styrene, n-butyl acrylate, and divinylbenzene charged to the mixing vessel were changed to 350 parts, 650 parts, and 18 parts, respectively; and in the above (Preparation of emulsion 1-2), the stirring time after adding the anionic surfactant and ion-exchanged water was changed to 4 hours.

[0186] <Preparation of specific resin particle dispersion 8> Specific resin dispersion 8 was obtained in the same manner as in <Preparation of specific resin dispersion 1> above, except that in the above (Preparation of emulsion 1-1), the amounts of styrene, n-butyl acrylate, and divinylbenzene charged to the mixing vessel were changed to 35 parts, 65 parts, and 1.9 parts, respectively, and in the above (Preparation of emulsion 1-2), the amounts of styrene, n-butyl acrylate, and divinylbenzene charged to the mixing vessel were changed to 350 parts, 650 parts, and 19 parts, respectively.

[0187] <Preparation of specific resin particle dispersion 9> Specific resin dispersion 9 was obtained in the same manner as in <Preparation of specific resin dispersion 1> above, except that in the above (Preparation of emulsion 1-1), 50 parts of styrene, 50 parts of n-butyl acrylate, and 2.2 parts of divinylbenzene were charged to the mixing vessel.

[0188] <Preparation of specific resin particle dispersion 10> Specific resin dispersion 10 was obtained in the same manner as in <Preparation of specific resin dispersion 1> above, except that in the above (Preparation of emulsion 1-1), the amount of styrene charged to the mixing vessel was changed to 52 parts, n-butyl acrylate to 48 parts, and divinylbenzene to 2.2 parts.

[0189] <Preparation of specific resin particle dispersion 11> Specific resin dispersion 11 was obtained in the same manner as in <Preparation of specific resin dispersion 1> above, except that the materials charged into the mixing vessel in the above (Preparation of emulsion 1-1) were changed from 40 parts of styrene to 35 parts of styrene and from 60 parts of n-butyl acrylate to 65 parts of 2-ethylhexyl acrylate, and the materials charged into the mixing vessel in the above (Preparation of emulsion 1-2) were changed from 600 parts of styrene to 350 parts of styrene and from 400 parts of n-butyl acrylate to 650 parts of 2-ethylhexyl acrylate.

[0190] <Preparation of specific resin particle dispersion 12> Specific resin dispersion 12 was obtained in the same manner as in <Preparation of specific resin dispersion 1> above, except that in the above (Preparation of emulsion 1-1), the material charged into the mixing vessel was changed from 60 parts of n-butyl acrylate to 60 parts of 2-ethylhexyl acrylate, and in the above (Preparation of emulsion 1-2), the material charged into the mixing vessel was changed from 600 parts of styrene to 400 parts of styrene, and from 400 parts of n-butyl acrylate to 600 parts of 2-ethylhexyl acrylate.

[0191] <Preparation of specific resin particle dispersion 13> Specific resin dispersion 13 was obtained in the same manner as in <Preparation of specific resin dispersion 1> above, except that in the above (Preparation of emulsion 1-1), the material charged into the mixing vessel was changed from 60 parts of n-butyl acrylate to 60 parts of acrylic isostearate, and in the above (Preparation of emulsion 1-2), the material charged into the mixing vessel was changed from 600 parts of styrene to 400 parts of styrene, and from 400 parts of n-butyl acrylate to 600 parts of acrylic isostearate.

[0192] <Preparation of specific resin particle dispersion 14> Specific resin dispersion 14 was obtained in the same manner as in <Preparation of specific resin dispersion 1> above, except that the materials charged into the mixing vessel in the above (Preparation of emulsion 1-1) were changed from 40 parts of styrene to 42 parts of styrene and from 60 parts of n-butyl acrylate to 58 parts of acrylic isostearate, and the materials charged into the mixing vessel in the above (Preparation of emulsion 1-2) were changed from 600 parts of styrene to 420 parts of styrene and from 400 parts of n-butyl acrylate to 580 parts of acrylic isostearate.

[0193] <Preparation of specific resin particle dispersion 15> Specific resin dispersion 15 was obtained in the same manner as in <Preparation of specific resin dispersion 1> above, except that the materials charged into the mixing vessel in the above (Preparation of emulsion 1-1) were changed from 40 parts of styrene to 35 parts of styrene, from 60 parts of n-butyl acrylate to 65 parts of 2-ethylhexyl acrylate, and from 2.0 parts of divinylbenzene to 2.5 parts of divinylbenzene, and the materials charged into the mixing vessel in the above (Preparation of emulsion 1-2) were changed from 600 parts of styrene to 350 parts of styrene, from 400 parts of n-butyl acrylate to 650 parts of 2-ethylhexyl acrylate, and from 2.0 parts of divinylbenzene to 25 parts of divinylbenzene, and the temperature of the first reaction solution in the above (Preparation of specific resin particle dispersion 1) was changed from 60°C to 70°C.

[0194] <Preparation of specific resin particle dispersion 16> Specific resin dispersion 16 was obtained in the same manner as in <Preparation of specific resin dispersion 1> above, except that the materials charged into the mixing vessel in the above (Preparation of emulsion 1-1) were changed from 40 parts of styrene to 35 parts of styrene, from 60 parts of n-butyl acrylate to 60 parts of 2-ethylhexyl acrylate, and from 2.0 parts of divinylbenzene to 2.5 parts of divinylbenzene, and the materials charged into the mixing vessel in the above (Preparation of emulsion 1-2) were changed from 600 parts of styrene to 400 parts of styrene, from 400 parts of n-butyl acrylate to 600 parts of 2-ethylhexyl acrylate, and from 2.0 parts of divinylbenzene to 25 parts of divinylbenzene.

[0195] <Preparation of specific resin particle dispersion 17> Specific resin dispersion 17 was obtained in the same manner as in <Preparation of specific resin dispersion 1> above, except that divinylbenzene was not added in the above (Preparation of emulsion 1-1) and the above (Preparation of emulsion 1-2).

[0196] <Preparation of specific resin particle dispersion 18> ·Amorphous resin dispersion liquid 150 parts by mass Ion-exchanged water 175 parts by weight n-Butyl acrylate 170 parts by mass 10% ammonia water 3 parts by weight The atmosphere in the reaction vessel was replaced with nitrogen, and the above ingredients were mixed and heated to 75°C while stirring. A solution of 1.5 parts by mass of ammonium persulfate in 100 parts by mass of ion-exchanged water was added dropwise to the reaction vessel over 2 hours. The reaction was continued for another 3 hours at 75°C to obtain Specific Resin Dispersion 18.

[0197] <Preparation of specific resin particle dispersion 19> Specific resin dispersion 19 was obtained in the same manner as in <Preparation of specific resin dispersion 1> above, except that the materials charged into the mixing vessel in the above (Preparation of emulsion 1-1) were changed from 40 parts of styrene to 18 parts of styrene and from 60 parts of n-butyl acrylate to 82 parts of acrylic isostearate, and the materials charged into the mixing vessel in the above (Preparation of emulsion 1-2) were changed from 600 parts of styrene to 180 parts of styrene and from 400 parts of n-butyl acrylate to 820 parts of acrylic isostearate.

[0198] <Preparation of specific resin particle dispersion 20> Specific resin dispersion 20 was obtained in the same manner as in <Preparation of specific resin dispersion 1> above, except that in the above (Preparation of emulsion 1-1), the materials charged into the mixing vessel were changed from 40 parts of styrene to 20 parts of styrene and from 60 parts of n-butyl acrylate to 80 parts of acrylic isostearate, and in the above (Preparation of emulsion 1-2), the materials charged into the mixing vessel were changed from 600 parts of styrene to 200 parts of styrene and from 400 parts of n-butyl acrylate to 800 parts of acrylic isostearate.

[0199] <Preparation of specific resin particle dispersion 21> Specific resin dispersion 21 was obtained in the same manner as in <Preparation of specific resin dispersion 1> above, except that the materials charged into the mixing vessel in the above (Preparation of emulsion 1-1) were changed from 40 parts of styrene to 50 parts of styrene and from 60 parts of n-butyl acrylate to 50 parts of cyclohexyl acrylate, and the materials charged into the mixing vessel in the above (Preparation of emulsion 1-2) were changed from 600 parts of styrene to 500 parts of styrene and from 400 parts of n-butyl acrylate to 500 parts of cyclohexyl acrylate.

[0200] <Preparation of specific resin particle dispersion 22> Specific resin dispersion 22 was obtained in the same manner as in <Preparation of specific resin dispersion 1> above, except that in the above (Preparation of emulsion 1-1), the materials charged into the mixing vessel were changed from 40 parts of styrene to 45 parts of styrene and from 60 parts of n-butyl acrylate to 55 parts of cyclohexyl acrylate, and in the above (Preparation of emulsion 1-2), the materials charged into the mixing vessel were changed from 600 parts of styrene to 450 parts of styrene and from 400 parts of n-butyl acrylate to 550 parts of cyclohexyl acrylate.

[0201] <Preparation of specific resin particle dispersion 23> Specific resin dispersion 23 was obtained in the same manner as in <Preparation of specific resin dispersion 1> above, except that the materials charged into the mixing vessel in the above (Preparation of emulsion 1-1) were changed from 40 parts of styrene to 49 parts of styrene and from 60 parts of n-butyl acrylate to 51 parts of cyclohexyl acrylate, and the materials charged into the mixing vessel in the above (Preparation of emulsion 1-2) were changed from 600 parts of styrene to 490 parts of styrene and from 510 parts of n-butyl acrylate to 550 parts of cyclohexyl acrylate.

[0202] <Preparation of specific resin particle dispersion 24> Specific resin dispersion 24 was obtained in the same manner as in <Preparation of specific resin dispersion 1> above, except that in the above (Preparation of emulsion 1-1), the material charged into the mixing vessel was changed from 60 parts of n-butyl acrylate to 60 parts of cyclohexyl acrylate, and in the above (Preparation of emulsion 1-2), the material charged into the mixing vessel was changed from 600 parts of styrene to 400 parts of styrene, and from 510 parts of n-butyl acrylate to 600 parts of cyclohexyl acrylate.

[0203] <Preparation of specific resin particle dispersion 25> Specific resin dispersion 25 was obtained in the same manner as in the above <Preparation of specific resin dispersion 1>, except that the amount of anionic surfactant added in the above (Preparation of emulsion 1-1) was changed to 2.2 parts.

[0204] <Preparation of specific resin particle dispersion 26> Specific resin dispersion 26 was obtained in the same manner as in the above <Preparation of specific resin dispersion 1>, except that the amount of anionic surfactant added in the above (Preparation of emulsion 1-1) was changed to 2.0 parts.

[0205] <Preparation of specific resin particle dispersion 27> Specific resin dispersion 27 was obtained in the same manner as in the above <Preparation of specific resin dispersion 1>, except that the amount of anionic surfactant added in the above (Preparation of emulsion 1-1) was changed to 0.015 parts.

[0206] <Preparation of specific resin particle dispersion 28> Specific resin dispersion 28 was obtained in the same manner as in the above <Preparation of specific resin dispersion 1>, except that the amount of anionic surfactant added in the above (Preparation of emulsion 1-1) was changed to 0.01 parts.

[0207] <Preparation of specific resin particle dispersion 29> According to the preparation of styrene acrylic resin particle dispersion (1) disclosed in Japanese Patent No. 6274057, specific resin particle dispersion 29 was prepared as follows. Styrene: 77 parts n-Butyl acrylate: 23 parts 1,10-decanediol diacrylate: 0.4 parts Dodecanethiol: 0.7 parts The above materials were mixed and dissolved, and a solution of 1.0 part of anionic surfactant (Dowfax 2A1, manufactured by Dow Chemical Company) dissolved in 60 parts of ion-exchanged water was added to the mixture, and the mixture was dispersed and emulsified in a flask to produce an emulsion. Next, 2.0 parts of an anionic surfactant (Dowfax 2A1 manufactured by The Dow Chemical Company) was dissolved in 90 parts of ion-exchanged water, and 20 parts of the emulsion was added thereto. Further, 10 parts of ion-exchanged water in which 1.0 part of ammonium persulfate had been dissolved was added. After that, the remaining emulsion was added over a period of 3 hours, and the atmosphere in the flask was replaced with nitrogen. Heat the solution in the flask in an oil bath to 65°C while stirring, and emulsify for 5 hours. The polymerization was continued to obtain specific resin particle dispersion liquid 29. The solid content of specific resin particle dispersion liquid 29 was adjusted to 35% by adding ion-exchanged water as necessary.

[0208] <Preparation of Colorant Dispersion> ·CIPigment Blue 15:3 (Dainichiseika Industries): 70 copies Anionic surfactant (Neogen RK manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 5 parts Ion-exchanged water: 200 parts The above materials were mixed and dispersed for 10 minutes using a homogenizer (Ultra Turrax T50 manufactured by IKA Corporation). Ion-exchanged water was added so that the solid content of the dispersion was 20% by mass, and a colorant dispersion containing colorant particles with a volume average particle size of 170 nm was obtained.

[0209] <Preparation of release agent dispersion> Paraffin wax (HNP-9 manufactured by Nippon Seiro Co., Ltd.): 50 parts Anionic surfactant (Neogen RK manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 1 part Ion-exchanged water: 150 parts The above materials were mixed and heated to 95°C, dispersed using a homogenizer (Ultra Turrax T50 manufactured by IKA), and then dispersed using a Manton-Gaulin high-pressure homogenizer (manufactured by Gaulin) to obtain a release agent dispersion liquid (solid content 30% by mass) in which release agent particles were dispersed. The volume average particle size of the release agent particles was 180 nm.

[0210] Example 1 ·Amorphous resin particle dispersion: 150 parts ·Crystalline resin particle dispersion 1: 41 parts ·Specified resin particle dispersion 1: 21 parts Colorant dispersion: 39 parts Release agent dispersion: 14 parts Anionic surfactant (Neogen RK manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 15 parts Ion-exchanged water: 100 parts The above materials were placed in a reaction vessel equipped with a thermometer, pH meter, and stirrer, heated to 30°C from the outside using a mantle heater, and maintained at 150 rpm for 30 minutes while stirring. Next, a 0.3N aqueous nitric acid solution was added to adjust the pH to 3.0, and a 3% by weight aqueous polyaluminum chloride solution was added while dispersing using a homogenizer (IKA Ultra-Turrax T50). The temperature was then raised to 50°C while stirring and maintained for 30 minutes. Next, 70 parts of the amorphous resin particle dispersion was added and maintained for 1 hour. A 0.1N aqueous sodium hydroxide solution was added to adjust the pH to 8.5, and the mixture was heated to 85°C while continuing to stir and maintained for 5 hours. The mixture was then cooled, solid-liquid separated, and the solid matter was washed and dried, yielding toner particles with a volume average particle size of 4.8 μm.

[0211] 100 parts of the obtained toner particles and 0.7 parts of dimethylsilicone oil-treated silica particles (RY200 manufactured by Nippon Aerosil Co., Ltd.) were mixed in a Henschel mixer to obtain a toner. Then, 8 parts of the obtained toner and 100 parts of the following carrier were mixed to obtain a developer.

[0212] -Creating a carrier- Ferrite particles (average particle size 50 μm) 100 parts Toluene 14 parts Styrene / methyl methacrylate copolymer (copolymerization ratio 15 / 85) 3 parts Carbon black 0.2 parts The above components except for the ferrite particles were dispersed in a sand mill to prepare a dispersion liquid, and this dispersion liquid was placed in a vacuum degassing kneader together with the ferrite particles, and the mixture was dried under reduced pressure while stirring to obtain a carrier.

[0213] <Examples 2 to 3, 9 to 11, 18 to 19, 29 to 30, 32 to 35, 40 to 43, Comparative Examples 1, 2, and 4> The toner particles, toner, and developer of each example were obtained in the same manner as in Example 1, except that the specific resin particle dispersion liquid 1 was changed to a specific resin particle dispersion liquid as shown in Table 1.

[0214] <Examples 4, 5, 8, 22 to 28, Comparative Example 3> The toner particles, toner, and developer of each example were obtained in the same manner as in Example 1, except that the amounts of the amorphous resin dispersion, the crystalline resin particle dispersion 1, and the specific resin particle dispersion 1 charged into the reaction vessel during the preparation of the toner particles were changed as follows:

[0215] Example 4 Amorphous resin dispersion: 157 parts Crystalline resin particle dispersion 1: 56 parts Specific resin particle dispersion 1: 4.0 parts Example 5 Amorphous resin dispersion: 152 parts Crystalline resin particle dispersion 1: 34 parts Specific resin particle dispersion 1: 25 parts Example 8 Amorphous resin dispersion: 153 parts Crystalline resin particle dispersion 1: 10 parts Specific resin particle dispersion 1: 43 parts

[0216] Example 22 Amorphous resin particle dispersion: 81 parts Crystalline resin particle dispersion 1: 135.0 parts Specific resin particle dispersion 1: 4.0 parts Example 23 Amorphous resin particle dispersion: 106 parts Crystalline resin particle dispersion 1: 109.0 parts Specific resin particle dispersion 1: 4.0 parts Example 24 Amorphous resin particle dispersion: 150 parts Crystalline resin particle dispersion 1: 11.0 parts Specific resin particle dispersion 1: 44.0 parts

[0217] Example 25 Amorphous resin particle dispersion: 206 parts Crystalline resin particle dispersion 1: 6 parts Specific resin particle dispersion 1: 2 parts Example 26 Amorphous resin particle dispersion: 206 parts Crystalline resin particle dispersion 1: 6 parts Specific resin particle dispersion 1: 3 parts Example 27 Amorphous resin particle dispersion: 109 parts Crystalline resin particle dispersion 1: 30 parts Specific resin particle dispersion 1: 63 parts

[0218] Example 28 Amorphous resin particle dispersion: 108 parts Crystalline resin particle dispersion 1: 29 parts Specific resin particle dispersion 1: 65 parts Comparative Example 3 Amorphous resin dispersion: 152 parts Crystalline resin particle dispersion 1: 0 parts Specific resin particle dispersion 1: 50 parts

[0219] <Examples 6, 7, 12 to 17, 20, 21, 31, 36 to 39> The toner particles, toner, and developer of each example were obtained in the same manner as in Example 1, except that the types of the crystalline resin particle dispersion liquid and the specific resin particle dispersion liquid were changed to the combinations shown in Table 1.

[0220] <Gross unevenness evaluation> The gross variation was calculated and the results are shown in the table. The standard deviation σ was calculated for the 50 total 60-degree gloss measurements taken in calculating the "gloss of the image after heating." Based on the standard deviation σ, gloss unevenness was evaluated according to the following evaluation criteria. -Evaluation criteria- A:σ<3.0 B:3.0≦σ<5.0 C:5.0≦σ<8.0 D:8.0≦σ

[0221] [Table 1-1]

[0222] [Table 1-2]

[0223] The abbreviations in the table are explained below. Crystalline PES: Crystalline polyester resin Crystalline POE: Crystalline polyether resin St / Ac: styrene-(meth)acrylic copolymer resin particles PES / Ac: specific resin particles containing polyester resin and acrylic resin - "Content (%)" of specific resin particles: The content of resin particles in the entire toner for developing electrostatic images

[0224] From the above results, it is apparent that the toner of this example is excellent in suppressing uneven gloss after the temperature of the image has risen. [Explanation of symbols]

[0225] 1Y, 1M, 1C, 1K Photoconductor (an example of an image carrier) 2Y, 2M, 2C, 2K Charging roll (an example of charging means) 3. Exposure device (an example of an electrostatic image forming means) 3Y, 3M, 3C, 3K laser beam 4Y, 4M, 4C, 4K developing device (an example of 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 cartridges 10Y, 10M, 10C, 10K image forming units 20 Intermediate transfer belt (an example of an intermediate transfer body) 22 Drive Roll 24 Support Roll 26 Secondary transfer roll (an example of a secondary transfer means) 30 Intermediate transfer body cleaning device 107 Photoconductor (an example of an image carrier) 108 Charging roll (an example of charging means) 109 Exposure device (an example of electrostatic image forming means) 111 Developing device (an example of developing means) 112 Transfer device (an example of transfer means) 113 Photosensitive drum cleaning device (an example of cleaning means) 115 Fixing device (an example of fixing means) 116 Mounting Rail 118 Exposure opening 117 Cabinet 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 comprising toner particles containing a binder resin including an amorphous polyester resin and a crystalline polyester resin, and crosslinked resin particles that are styrene-(meth)acrylic copolymer resin particles crosslinked by covalent bonds, the toner particles being obtained by a dry process or a wet process using the binder resin and the crosslinked resin particles as raw materials, The toner for developing electrostatic images, wherein the crosslinked resin particles have a loss coefficient tan δS(30) of 1 or more at 30°C, and the resin particles have a loss coefficient tan δS(50) of less than 1 at 50°C.

2. 2. The toner for developing electrostatic images according to claim 1, wherein the difference between the loss coefficient tan δS(30) and the loss coefficient tan δS(50) (tan δS(30) - tan δS(50)) is 0.5 or more.

3. 3. The toner for developing electrostatic images according to claim 2, wherein the difference between the loss coefficient tan δS(30) and the loss coefficient tan δS(50), (tan δS(30) - tan δS(50)), is 0.8 or more and 3.0 or less.

4. When the loss factor of the crystalline polyester resin at 30°C is tan δC(30) and the loss factor of the crystalline polyester resin at 50°C is tan δC(50), The ratio (tan δS(30) / tan δC(30)) of the loss factor tan δS(30) to the loss factor tan δC(30) is 20.0 or more and 60.0 or less, 4. The toner for developing electrostatic images according to claim 1, wherein the ratio (tan δS(50) / tan δC(50)) of the loss coefficient tan δS(50) to the loss coefficient tan δC(50) is 2.0 or more and 20.0 or less.

5. 5. The toner for developing electrostatic images according to claim 1, wherein a ratio (S / C) of a content C of the crystalline polyester resin to a content S of the crosslinked resin particles is 0.05 or more and 5.0 or less on a mass basis.

6. 6. The toner for developing electrostatic images according to claim 1, wherein the content of the crosslinked resin particles is 1% by mass or more and 30% by mass or less based on the entire toner for developing electrostatic images.

7. 7. The toner for developing electrostatic images according to claim 1, wherein a difference between a solubility parameter SP value (S) of the crosslinked resin particles and a solubility parameter SP value (R) of the binder resin (SP value (S) - SP value (R)) is -1.0 or more and 1.0 or less.

8. 8. The toner for developing electrostatic images according to claim 1, wherein a difference (SP value (S) - SP value (C)) between a solubility parameter SP value (S) of the crosslinked resin particles and a solubility parameter SP value (C) of the crystalline polyester resin is 0 or more and 2.0 or less.

9. 9. The toner for developing electrostatic images according to claim 1, wherein the dispersed diameter of the crosslinked resin particles is 50 nm or more and 500 nm or less.

10. A toner comprising toner particles obtained by a dry process or a wet process using a binder resin containing an amorphous polyester resin and a crystalline polyester resin, and crosslinked resin particles that are styrene-(meth)acrylic copolymer resin particles crosslinked by covalent bonds as raw materials, and the toner comprises the binder resin and the crosslinked resin particles; Toner amount: 13.5 g / m ２ Electrostatic image developing toner, which forms a 25 mm x 25 mm square image, and which exhibits a change in gloss of the image of 0% or more and 10.0% or less before and after heating the image at 50°C for 30 days.

11. An electrostatic image developer comprising the toner for developing electrostatic images according to any one of claims 1 to 10.

12. A toner for developing electrostatic images according to any one of claims 1 to 10 is contained therein, A toner cartridge that is detachably attached to an image forming device.

13. a developing unit containing the electrostatic image developer according to claim 11 and developing an electrostatic image formed on a surface of an image carrier into a toner image by using the electrostatic image developer, A process cartridge is detachably mounted in an image forming apparatus.

14. an image carrier; a charging means for charging the surface of the image carrier; an electrostatic image forming means for forming an electrostatic image on the charged surface of the image carrier; a developing unit containing the electrostatic image developer according to claim 11 and developing the electrostatic image formed on the surface of the image carrier into a toner image by using the electrostatic 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; a fixing means for fixing the toner image transferred onto the surface of the recording medium; An image forming apparatus comprising:

15. a charging step of charging the surface of the image carrier; an electrostatic image forming step of forming an electrostatic image on the charged surface of the image carrier; a developing step of developing the electrostatic image formed on the surface of the image carrier into a toner image by using the electrostatic image developer according to claim 11; a transfer step of transferring the toner image formed on the surface of the image carrier to the surface of a recording medium; a fixing step of fixing the toner image transferred onto the surface of the recording medium; An image forming method comprising the steps of:

Images