Toner, toner storage unit, image forming apparatus, image forming method, and method for manufacturing print

Abstract

To provide a toner that can ensure charge stability over a long period while achieving both low temperature fixability and heat-resistant storage properties, and can prevent abnormal images over a long period.SOLUTION: A toner includes base particles containing an amorphous polyester resin and wax, and an external additive. The external additive includes silica having a surface coated with a hydroxide of a metal element. The silica having the surface coated with the hydroxide of the metal element has a volume specific resistance of 2.0×1010 Ω cm or more and 1.0×1011 Ω cm or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a toner, a toner storage unit, an image forming apparatus, an image forming method, and a method for producing a printed matter. [Background technology]

[0002] In recent years, toners have become more important for the purpose of reducing energy consumption and suppressing volatile fine particle components, and it is particularly important to improve low-temperature fixability while maintaining heat-resistant storage stability. At the same time, it is also important to maintain a stable charge level over the long term and maintain image quality. From this perspective, not only the formulation of the toner base but also the selection of external additives plays an important role.

[0003] On the other hand, in recent years there has been a trend to adopt materials that pose fewer safety risks, and external additives that can replace the titanium oxide that has been used traditionally are being searched for. For example, Patent Document 1 proposes the use of silica particles in combination with an external additive treated with aluminum hydroxide and an organic substance, which is said to achieve excellent image density, charge amount, and charge stability. Furthermore, Patent Document 2 proposes the combined use of a fine powder of a composition of aluminum hydroxide and silica, the surface of which has been silane-treated, and small-particle silica having an average primary particle size smaller than that of the fine powder. According to Patent Document 2, a toner with high long-term environmental charging performance can be realized. Summary of the Invention [Problem to be solved by the invention]

[0004] However, when titanium oxide is not used as in Patent Documents 1 and 2, satisfactory results have not yet been obtained in controlling the charge amount. Furthermore, in order to stabilize the charge amount over time, it is necessary to control not only the type of material but also the physical properties of the external additive. For these reasons, there is a demand for a technology that can ensure charge stability over a long period of time while achieving both low-temperature fixability and heat-resistant storage stability, and can prevent abnormal images over a long period of time.

[0005] An object of the present invention is to provide a toner that can ensure charging stability over a long period of time while achieving both low-temperature fixability and heat-resistant storage stability, and can prevent abnormal images over a long period of time. [Means for solving the problem]

[0006] In order to solve the above problems, the toner of the present invention is a toner comprising base particles containing an amorphous polyester resin and a wax, and an external additive, wherein the external additive comprises silica whose surface is coated with a hydroxide of a metal element, and the volume resistivity of the silica whose surface is coated with the hydroxide of a metal element is 2.0×10 10 Ω cm or more 1.0×10 11 It is characterized by a resistance of Ω·cm or less. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a toner that can ensure both low-temperature fixability and heat-resistant storage stability, and can ensure charging stability over a long period of time, thereby preventing abnormal images over a long period of time. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating an embodiment of an image forming apparatus according to the present invention; [Figure 2] FIG. 10 is a diagram illustrating another embodiment of the image forming apparatus of the present invention. [Figure 3] FIG. 10 is a diagram illustrating another embodiment of the image forming apparatus of the present invention. [Figure 4] FIG. 2 is a diagram illustrating an image forming unit. DETAILED DESCRIPTION OF THE INVENTION

[0009] The toner, toner storage unit, image forming apparatus, image forming method, and method for producing printed matter according to the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the following embodiments, and other modifications, additions, corrections, deletions, and other changes can be made within the scope of what a person skilled in the art can conceive. Any embodiment is within the scope of the present invention as long as it achieves the functions and effects of the present invention.

[0010] (Toner composition) The toner of the present invention is a toner comprising base particles containing an amorphous polyester resin and a wax, and an external additive, wherein the external additive comprises silica whose surface is coated with a hydroxide of a metal element, and the volume resistivity of the silica whose surface is coated with the hydroxide of a metal element is 2.0×10 10 Ω cm or more 1.0×10 11 It is characterized by a resistance of Ω·cm or less. According to the present invention, it is possible to ensure both low-temperature fixability and heat-resistant storage stability, while ensuring charge stability over a long period of time and preventing abnormal images over a long period of time.

[0011] The average circularity of the toner is preferably 0.930 to 0.960. When the average circularity is in the above range, it is easy to achieve both transferability and cleanability in an appropriate range.

[0012] The average circularity of the toner can be measured using a known particle measuring device, for example, a wet flow particle size and shape analyzer FPIA-3000 and analysis software FPIA-3000 Data Processing Program for FPIA version 00-10 (manufactured by Sysmex Corporation).

[0013] Specifically, for example, 0.1 to 0.5 mL of a 10% aqueous solution of alkylbenzene sulfonate Neogen SC-A (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and 0.1 to 0.5 g of toner or toner base particles are added to a 100 mL glass beaker, and then the mixture is stirred with a microspatula and 80 mL of ion-exchanged water is added. Next, the mixture is dispersed for 1 minute using an ultrasonic disperser UH-50 (manufactured by SMT) under conditions of 20 kHz and 50 W / 10 cm3, and then dispersed for a total of 5 minutes to obtain a measurement sample. Here, the particle concentration is determined to be 4000 to 8000 particles / 10 cm3. -3 cm 3 Using the measurement sample, the average circularity of particles having a circle-equivalent diameter in the desired range can be measured. The average circularity of the toner particles may be the average circularity of the toner base particles.

[0014] <External additives> The toner of the present invention contains an external additive, which coats the wax in the toner base particles with the external additive, thereby suppressing deterioration in transferability and durability due to the wax. Furthermore, coating the toner surface with fine particles of the external additive reduces the contact area between resin particles contained in the toner base particles, thereby improving the fluidity, storage stability, developability, transferability, and durability of the toner.

[0015] The external additive contained in the toner of the present invention includes silica (hereinafter, sometimes referred to as "silica"), the surface of which is at least partially coated with a hydroxide of a metal element. By containing such silica as an external additive in the toner, charging stability can be ensured and the occurrence of abnormal images can be suppressed.

[0016] The silica, the surface of which is at least partially coated with a hydroxide of a metal element, preferably has a hydrophobicity of 55 (MeOH%) or more. When the silica has a hydrophobicity of 55 (MeOH%) or more, it can have an appropriate cleaning performance and can suppress the occurrence of abnormal images.

[0017] The degree of hydrophobicity can be measured, for example, by the following method. First, 50 ml of ion-exchanged water and 0.2 g of sample are placed in a beaker, and methanol is added dropwise while stirring. As the methanol concentration in the beaker increases, the sample gradually settles, and the mass fraction of methanol in the methanol-water mixture at the end point when the entire sample has settled is taken as the hydrophobicity (MeOH%).

[0018] In the present invention, the volume resistivity of silica whose surface is coated with a hydroxide of a metal element is 2.0 × 10 10 Ω cm or more 1.0×10 11 Ω·cm or less. By having the volume resistivity in the above range, it is possible to maintain a high level of charging stability for a long period of time.

[0019] The volume resistivity of silica coated with a hydroxide of a metal element is 3.0 × 10 10 Ω cm or more 7.0×10 10 It is preferable that the volume resistivity is Ω·cm or less. When the volume resistivity is in the above range, it is possible to maintain a higher level of charging stability for a long period of time.

[0020] The volume resistivity of the silica at least partly coated with a hydroxide of a metal element is measured, for example, by the following method. First, a cell consisting of a fluororesin container containing two electrodes with a surface area of ​​2.5 cm x 4 cm, spaced 0.2 cm apart, was used. The sample was placed between the two electrodes and tapped 10 times at a drop height of 1 cm and a tapping speed of 30 times per minute. Next, a DC voltage of 1,000 V was applied between the two electrodes containing the sample, and the resistance value r [Ω] after 30 seconds was measured using a High Resistance Meter 4329A (Yokogawa Hewlett-Packard Co., Ltd.). The volume resistivity [Ω·cm] of the sample was calculated by inputting the measured resistance value r into the following equation: r×(2.5×4) / 0.2...formula

[0021] The silica at least partially coated with a hydroxide of a metal element preferably has its outermost surface coated with an alkylsilane. This makes it easier to achieve both a certain level of hydrophobicity and a certain level of volume resistivity, thereby maintaining a higher level of charging stability and suppressing abnormal images. It is sufficient that at least a portion of the area is coated with alkylsilane. Examples of alkylsilanes that can be used here include the alkylsilanes exemplified in the section "Hydrophobic Treatment Agents Used in Hydrophobic Treatment" below.

[0022] The metal element in the silica at least partly surface-coated with a hydroxide of a metal element can be appropriately selected, and is preferably selected from aluminum, zinc, magnesium, and iron, and more preferably selected from aluminum, zinc, and magnesium. If the hydroxide of these metal elements is used, it is easy to control the volume resistivity of the silica to a desired range. For these reasons, the hydroxide of the metal element is preferably one or more hydroxides selected from aluminum, zinc, magnesium and iron, and more preferably one or more hydroxides selected from aluminum, zinc and magnesium.

[0023] The average particle size of the silica, at least a portion of which is surface-coated with a hydroxide of a metal element, is preferably 10 nm to 30 nm. By having the average particle size of the silica in the above range, the coating state of the toner surface can be optimized, making it easier to achieve both low-temperature fixability and heat-resistant storage stability. The average particle size referred to here is the number-average particle size. The average particle size of silica coated with a hydroxide of a metal element may be the average primary particle size of silica particles before being coated with a hydroxide of a metal element.

[0024] The average primary particle diameter of the silica particles can be determined, for example, by obtaining an SEM image of the silica particles using a field emission scanning electron microscope (SU8230, manufactured by Hitachi High-Technologies Corporation) and measuring the number average particle diameter by image analysis. Specifically, for example, a silica particle sample is dispersed in tetrahydrofuran, the solvent is removed on a substrate, and the sample is dried. The sample is observed with the SEM to obtain an image, and the maximum length of the primary particles for each particle is measured under the following measurement conditions. The average value of 50 particles is calculated to determine the average primary particle diameter of the silica particles.

[0025] [SEM measurement conditions] Accelerating voltage: 2.0 kV WD (Working Distance): 5.0 mm Observation magnification: 100,000 times

[0026] The toner of the present invention may contain, as an external additive, other fine particles in addition to the silica at least partly coated with a hydroxide of a metal element, and one or more of inorganic fine particles, inorganic oxide fine particles, and resin fine particles may be used as the other fine particles.

[0027] The inorganic fine particles, inorganic oxide fine particles, and resin fine particles preferably have an average primary particle diameter of 5 nm to 2 μm. The content of the other fine particles in the toner varies depending on the type, but is preferably in the range of 0.01 to 5% by mass in the toner.

[0028] The surfaces of the other fine particles are preferably treated to be hydrophobic, and fine particles of inorganic oxides such as silica that have been treated to be hydrophobic are preferably used.

[0029] Examples of the inorganic fine particles include silica, alumina, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, pengala, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, silicon nitride, etc. These may be used alone or in combination of two or more.

[0030] Examples of the resin microparticles include resin microparticles made of polycondensation systems such as polystyrene, methacrylate ester or acrylate ester copolymers, silicone, benzoguanamine, and nylon obtained by soap-free emulsion polymerization, suspension polymerization, or dispersion polymerization, and polymer particles made of thermosetting resins.

[0031] The hydrophobic treatment agent used in the hydrophobic treatment is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include dimethyldichlorosilane, trimethylchlorosilane, methyltrichlorosilane, allyldimethyldichlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, p-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, chloromethyltrichlorosilane, p-Chlorophenyltrichlorosilane, 3-chloropropyltrichlorosilane, 3-chloropropyltrimethoxysilane, vinyltriethoxysilane, vinylmethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, divinyldichlorosilane, dimethylvinylchlorosilane, octyltrichlorosilane, decyltrichlorosilane, nonyltrichlorosilane, (4-t-propylphenyl (4-t-butylphenyl)-trichlorosilane, (4-t-butylphenyl)-trichlorosilane, dipentyl-dichlorosilane, dihexyl-dichlorosilane, dioctyl-dichlorosilane, dinonyl-dichlorosilane, didecyl-dichlorosilane, didodecyl-dichlorosilane, dihexadecyl-dichlorosilane, (4-t-butylphenyl)-octyl-dichlorosilane, dioctyl-dichlorosilane, didecenyl-dichlorosilane, dinonenyl-dichlorosilane, di-2-ethylhexyl-dic Examples of the chlorosilane include chlorosilane, di-3,3-dimethylpentyl-dichlorosilane, trihexyl-chlorosilane, trioctyl-chlorosilane, tridecyl-chlorosilane, dioctyl-methyl-chlorosilane, octyl-dimethyl-chlorosilane, (4-t-propylphenyl)-diethyl-chlorosilane, octyltrimethoxysilane, hexamethyldisilazane, hexaethyldisilazane, diethyltetramethyldisilazane, hexaphenyldisilazane, and hexatlyldisilazane.

[0032] In addition, titanate-based coupling agents and aluminum-based coupling agents can also be used.

[0033] A general powder mixer is used to mix the above-mentioned external additive and toner base particles, but a mixer that can adjust the internal temperature by being equipped with a jacket or the like is preferred, and for example, a V-type mixer, a rocking mixer, a Loedige mixer, a Nauta mixer, a Henschel mixer, or the like is preferably used.

[0034] The inorganic fine particles, inorganic oxide fine particles, and resin fine particles may be contained (internal added) in the toner.

[0035] The internal addition of the inorganic fine particles, inorganic oxide fine particles, and resin fine particles to the toner can improve transferability and durability, and can also improve the grindability of the toner. Furthermore, the combined use of external and internal addition can prevent the externally added inorganic fine particles and resin fine particles from being embedded in the toner, thereby stably achieving excellent transferability and improving durability.

[0036] <Toner base particles> The toner base particles (also referred to as base particles) contained in the toner contain an amorphous polyester resin and a wax.

[0037] <<Amorphous polyester resin>> The amorphous polyester resin contained in the toner of the present invention is not particularly limited and any known material can be used, but it is preferable that the resin contains at least bisphenol A and ethylene glycol as diol components. By containing bisphenol A as the diol component, good heat resistance of the toner can be ensured. Furthermore, by containing ethylene glycol as the diol component, good dispersibility with waxes having low SP values ​​can be maintained. As a result, the durability of the toner can be improved.

[0038] As the monomer units constituting the amorphous polyester resin, in addition to bisphenol A and ethylene glycol, a monomer unit of a dihydric alcohol may also be used. Examples of the dihydric alcohol include propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, hydrogenated bisphenol A, and diols obtained by polymerizing bisphenol A with a cyclic ether such as ethylene oxide or propylene oxide.

[0039] Furthermore, a trihydric or higher polyhydric alcohol can also be used in combination as a means for crosslinking the amorphous polyester resin. Examples of the trihydric or higher polyhydric alcohol include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, such as dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentatriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, and 1,3,5-trihydroxybenzene.

[0040] Examples of the acid component that forms the amorphous polyester resin include benzenedicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid, or their anhydrides; alkyldicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and azelaic acid, or their anhydrides; unsaturated dibasic acids such as maleic acid, citraconic acid, itaconic acid, alkenylsuccinic acid, fumaric acid, and mesaconic acid; and unsaturated dibasic acid anhydrides such as maleic anhydride, citraconic anhydride, itaconic anhydride, and alkenylsuccinic anhydride.

[0041] Furthermore, trivalent or higher polyvalent carboxylic acids can also be used as the acid component that forms the amorphous polyester resin. Examples include trimellitic acid, pyromellic acid, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxy-2-methyl-2-methylenecarboxypropane, tetra(methylenecarboxy)methane, 1,2,7,8-octanetetracarboxylic acid, empol trimer acid, or anhydrides or partial lower alkyl esters thereof.

[0042] The acid value of the amorphous polyester resin is preferably 0.1 mgKOH / g to 100 mgKOH / g, more preferably 0.1 mgKOH / g to 70 mgKOH / g, and even more preferably 0.1 mgKOH / g to 50 mgKOH / g. In the present invention, the molecular weight distribution of the amorphous polyester resin can be measured by gel permeation chromatography (GPC) using THF as a solvent.

[0043] <<Wax>> The wax contained in the toner of the present invention is not particularly limited, and can be appropriately selected from known waxes.

[0044] Examples of waxes include natural waxes such as plant waxes such as carnauba wax, cotton wax, wood wax, and rice wax; animal waxes such as beeswax and lanolin; mineral waxes such as ozokerite and cerusine; and petroleum waxes such as paraffin, microcrystalline, and petrolatum.

[0045] In addition to these natural waxes, examples include synthetic hydrocarbon waxes such as Fischer-Tropsch wax, polyethylene, and polypropylene; synthetic waxes such as esters, ketones, and ethers; and the like.

[0046] Furthermore, fatty acid amide compounds such as 12-hydroxystearic acid amide, stearic acid amide, phthalimide anhydride, and chlorinated hydrocarbons; low-molecular-weight crystalline polymer resins, such as homopolymers or copolymers of polyacrylates such as poly-n-stearyl methacrylate and poly-n-lauryl methacrylate (for example, copolymers of n-stearyl acrylate and ethyl methacrylate); and crystalline polymers having long alkyl groups in their side chains may also be used.

[0047] Among these, hydrocarbon waxes such as paraffin wax, microcrystalline wax, Fischer-Tropsch wax, polyethylene wax, and polypropylene wax are preferred.

[0048] The melting point of the wax is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 60°C or higher and lower than 95°C. When the melting point of the wax is 60°C or higher, the release agent is less likely to melt at low temperatures, and the heat-resistant storage stability of the toner can be maintained.When the melting point of the wax is lower than 95°C, the release agent is sufficiently melted by heating during fixing, and sufficient offset properties can be obtained.

[0049] The wax is preferably a hydrocarbon wax. The hydrocarbon wax has almost no compatibility with the amorphous polyester resin and the crystalline polyester resin, and can function independently of each other, so that it is preferable since it does not impair the softening effect of the crystalline polyester resin as a binder resin or the offset property of the release agent.

[0050] The wax is more preferably a hydrocarbon wax having a melting point of 60°C or higher and lower than 95°C. A hydrocarbon wax with a melting point of 60°C or higher but lower than 95°C can effectively act as a release agent between the fixing roller and the toner interface, thereby improving high-temperature offset resistance without applying a release agent such as oil to the fixing roller.

[0051] The wax content in the toner is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 2% by mass to 10% by mass, and more preferably 3% by mass to 8% by mass, in the toner. When the wax content in the toner is 2% by mass or more, high-temperature offset resistance and low-temperature fixability during fixing can be exhibited, and when it is 10% by mass or less, heat-resistant storage stability can be maintained and image fogging, etc. can be made less likely to occur. When the wax content is within the above range, high image quality and fixing stability can be further improved.

[0052] <<Crystalline polyester resin>> The toner of the present invention preferably further contains a crystalline polyester resin, which allows the toner to obtain better low-temperature fixability.

[0053] The melting point of the crystalline polyester resin is preferably 100 to 120° C. When the melting point of the crystalline polyester resin is 100° C. or higher, the glass transition temperature of the non-crystallized portion present in the crystalline polyester resin increases in accordance with the melting point. As a result, the glass transition temperature of the non-crystallized portion approaches the glass transition temperature of the amorphous polyester resin, increasing compatibility and improving low-temperature fixability. When the melting point of the crystalline polyester resin is 120° C. or less, the amount of heat required for melting during fixing is sufficient, making it easy to ensure low-temperature fixability.

[0054] The crystalline polyester resin is (I) a polycarboxylic acid consisting of a linear unsaturated aliphatic dicarboxylic acid or a reactive derivative thereof (such as an acid anhydride, a lower alkyl ester having 1 to 4 carbon atoms, or an acid halide); (II) a polyhydric alcohol consisting of a linear aliphatic diol; can be produced by subjecting the above to a polycondensation reaction in a conventional manner. If necessary, a small amount of another polycarboxylic acid can be added to the polycarboxylic acid (I).

[0055] Examples of the other polycarboxylic acids include: (i) Branched-chain unsaturated aliphatic dicarboxylic acid (ii) saturated aliphatic dicarboxylic acids and saturated aliphatic tricarboxylic acids and other saturated aliphatic polycarboxylic acids (iii) Aromatic polycarboxylic acids such as aromatic dicarboxylic acids and aromatic tricarboxylic acids etc.

[0056] The amount of the other polycarboxylic acids (i) to (iii) added is usually 30 mol % or less, preferably 10 mol % or less, relative to the amount of the polycarboxylic acid (I), and can be appropriately adjusted and added within a range in which the resulting polyester resin has crystallinity. Specific examples of the other polycarboxylic acids include dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, citraconic acid, phthalic acid, isophthalic acid, and terephthalic acid; and tricarboxylic or higher polycarboxylic acids such as trimellitic anhydride, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methylenecarboxypropane, and 1,2,7,8-octanetetracarboxylic acid.

[0057] If necessary, a small amount of other polyhydric alcohols can be added to the polyhydric alcohol (II), such as aliphatic branched-chain dihydric alcohols, cyclic dihydric alcohols, and trihydric or higher polyhydric alcohols.

[0058] The amount of the other polyhydric alcohol added is 30 mol % or less, preferably 10 mol % or less, relative to the amount of the polyhydric alcohol (II), and can be appropriately adjusted within the range in which the resulting polyester has crystallinity.

[0059] Examples of the other polyhydric alcohols include 1,4-bis(hydroxymethyl)cyclohexane, polyethylene glycol, bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct, and glycerin.

[0060] The crystalline polyester resin preferably has a sharp peak in its molecular weight distribution from the viewpoint of low-temperature fixability, and its molecular weight is preferably relatively low. The molecular weight of the crystalline polyester resin is preferably such that, in the molecular weight distribution of the o-dichlorobenzene soluble portion measured by gel permeation chromatography (GPC), the weight average molecular weight (Mw) is 5,500 to 6,500, the number average molecular weight (Mn) is 1,300 to 1,500, and the Mw / Mn ratio is 2 to 5.

[0061] The molecular weight distribution of the crystalline polyester resin is based on a molecular weight distribution diagram with logM (M is molecular weight) on the horizontal axis and mass% on the vertical axis. In the case of the crystalline polyester resin used in the present invention, the molecular weight distribution diagram preferably has a maximum value of the molecular weight peak in the range of 3.5 to 4.0 (mass%), and the half-value width of the maximum value of the peak is preferably 1.5 or less.

[0062] The content of the crystalline polyester resin in the toner base particles is preferably 5.0% by mass or less. By setting the content of the crystalline polyester resin in the toner base particles to 5.0% by mass or less, adhesion to the photoreceptor due to recrystallization after toner formation can be suppressed, and image blurring can be suppressed.

[0063] <<Aromatic petroleum resin>> The toner preferably further contains an aromatic petroleum resin. By containing an aromatic petroleum resin in the toner, the grindability when the toner is made into a pulverized toner can be improved. Furthermore, by containing an aromatic petroleum resin in the toner, the heat resistance can be improved while maintaining low-temperature fixability.

[0064] The aromatic petroleum resin is a resin synthesized using petroleum C9 fractions such as styrene, vinyltoluene, indene, etc. In particular, styrene copolymers of styrene or α-methylstyrene are preferred.

[0065] The weight-average molecular weight of the aromatic petroleum resin is preferably 2000 or more and 3500 or less. When the weight-average molecular weight is 2000 or more, durability in an actual machine can be easily ensured, and when the weight-average molecular weight is 3500 or less, good toner grindability can be easily ensured.

[0066] The styrene copolymer is not particularly limited, and examples thereof include styrene and its substituted polymers such as polystyrene, poly-p-styrene, and polyvinyltoluene, styrene-α-methylstyrene copolymer, styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-maleic acid copolymer, and styrene-maleic acid ester copolymer. Among these, styrene-α-methylstyrene copolymer is particularly preferred.

[0067] The glass transition temperature (Tg) of the styrene copolymer is preferably 60° C. or higher, and more preferably 65 to 85° C. When the Tg of the styrene resin is 60° C. or higher, the heat-resistant storage stability can be improved.

[0068] The Tg can be measured using a differential scanning calorimeter (Q-200, manufactured by TA Instruments). A specific measurement method involves placing approximately 5.0 mg of the target sample in an aluminum sample container, placing the sample container on a holder unit, setting it in an electric furnace, and heating it from -80°C to 150°C at a rate of 10°C / min in a nitrogen atmosphere to obtain a DSC curve. The glass transition temperature (Tg) of the target sample is determined from the obtained DSC curve using an analysis program in the differential scanning calorimeter.

[0069] When the toner of the present invention contains an aromatic petroleum resin and the crystalline polyester resin, the mass ratio of the crystalline polyester resin to the aromatic petroleum resin is preferably 1.0 or more and 1.2 or less.

[0070] The aromatic petroleum resin disperses in the toner to improve the grindability of the toner, but because it has a glass transition temperature above a certain level, it can inhibit low-temperature fixability. On the other hand, the crystalline polyester resin improves low-temperature fixability, but because it has a crystallized portion, it can inhibit the grindability of the toner. In addition, since crystalline polyester resins are generally partially compatible with amorphous polyester resins, the proportion of the crystallized portion in the toner can be slightly less than the amount added to the toner.

[0071] Therefore, when the toner of the present invention contains an aromatic petroleum resin and the crystalline polyester resin, it is preferable that the mass proportions of both materials in the toner be approximately the same in order to appropriately bring out the respective effects of both materials.

[0072] When the mass ratio of the crystalline polyester resin to the aromatic petroleum resin is within the above range, the effects of both materials, which have opposing effects on toner grindability and low-temperature fixability, can be appropriately brought out, and toner grindability and low-temperature fixability can both be achieved at a high level.

[0073] The content of the aromatic petroleum resin in the toner base particles is preferably 3.0% by mass or more, which can improve wax dispersibility and durability while maintaining a certain level of toner grindability.

[0074] <<Coloring agent>> The toner of the present invention preferably contains a colorant. As the colorant used in the toner of the present invention, all known dyes and pigments can be used, for example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, yellow ochre, yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR), permanent yellow (NCG), Balkan fast yellow (5G, R), tartrazine lake, quinoline yellow lake, anthrazan yellow BGL, isoindolinone yellow, red iron oxide, red lead, vermilion, Cadmium Red, Cadmium Mercury Red, Antimony Vermilion, Permanent Red 4R, Para Red, Faise Red, Parachlor Orthonitroaniline Red, Lithol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belcan Fast Rubin B, Brilliant Scarlet G, Lithol Rubin GX, Permanent Red F5R, Brilliant Carmine 6B, Pogment Scarlet Red 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thioindigo Red B, Thioindigo Maroon, Oil Red, Quinacridone Red, Pyrazolone Red, Polyazo Red, Chrome Vermilion, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkali Blue Lake, Peacock Couleur Lake, Victoria Blue Lake, Metal-free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue (RS, BC), Indigo, Ultramarine, Prussian Blue, Anthraquinone Blue, Fast Violet B, Methyl Violet Lake, Cobalt Purple, Manganese Purple, Dioxane Violet, Anthraquinone Violet, Chrome Green, Zinc Green, Chromium Oxide, Pyridian, Emerald Green, Pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake,Examples include malachite green lake, phthalocyanine green, anthraquinone green, titanium oxide, zinc oxide, lithopone, and mixtures thereof.

[0075] The content of the colorant in the toner is preferably 1 to 15% by mass, and more preferably 3 to 10% by mass.

[0076] In the production of the toner, a masterbatch in which the colorant is mixed with a resin may be used. The resin kneaded with the colorant to prepare the masterbatch may be the same as the resin described above. The resin kneaded with the colorant may be used alone or in combination of two or more.

[0077] The masterbatch can be obtained by mixing and kneading a resin and a colorant for preparing the masterbatch under high shear force. An organic solvent can be used to enhance the interaction between the colorant and the resin. Alternatively, a method known as the flushing method can be used, in which an aqueous paste of a colorant containing water is mixed and kneaded with a resin and an organic solvent, the colorant is transferred to the resin, and the water and organic solvent components are removed. The flushing method allows the colorant wet cake to be used as is, eliminating the need for drying, making it suitable for use. A high-shear dispersing device such as a three-roll mill is suitable for mixing and kneading in the flushing method.

[0078] The amount of the masterbatch used is preferably 0.1 to 20 parts by mass with respect to 100 parts by mass of the resin.

[0079] In preparing the masterbatch, it is preferable to disperse the colorant in a resin. The resin for preparing the masterbatch preferably has an acid value of 30 mgKOH / g or less and an amine value of 1 to 100, and more preferably an acid value of 20 mgKOH / g or less and an amine value of 10 to 50. When the resin for preparing the masterbatch has an acid value of 30 mgKOH / g or less, the chargeability does not decrease even under high humidity conditions and the dispersibility of the colorant is sufficient, and when the amine value is 1 to 100, the dispersibility of the colorant is sufficient.

[0080] The acid value of the resin for preparing the masterbatch can be measured by the method described in JIS K0070, and the amine value can be measured by the method described in JIS K7237.

[0081] A dispersant can be used to improve the dispersibility of the colorant. From the viewpoint of the dispersibility of the colorant, the dispersant preferably has high compatibility with the resin.

[0082] Examples of the dispersant include commercially available products such as "Ajisper PB821" and "Ajisper PB822" (manufactured by Ajinomoto Fine-Techno Co., Ltd.), "Disperbyk-2001" (manufactured by BYK-Chemie), and "EFKA-4010" (manufactured by EFKA).

[0083] From the viewpoint of dispersibility of the colorant, the mass average molecular weight of the dispersant is preferably 500 to 100,000, more preferably 3,000 to 100,000, even more preferably 5,000 to 50,000, and particularly preferably 5,000 to 30,000, as the molecular weight of the maximum value of the main peak in styrene-equivalent mass in gel permeation chromatography. When the molecular weight is 500 or more, the polarity is not too high and the dispersibility of the colorant is not likely to decrease, and when it is 100,000 or less, the affinity with the solvent is not too high and the dispersibility of the colorant is not likely to decrease.

[0084] The dispersant is preferably blended in the toner in a proportion of 0.1 to 10% by mass relative to the colorant. When the blending proportion of the dispersant is 0.1% by mass or more of the colorant, the colorant is sufficiently dispersible, and when the blending proportion is 10% by mass or less, the chargeability is less likely to decrease under high humidity conditions.

[0085] <<Charge control agent>> The toner of the present invention may contain a charge control agent, if necessary. Any known charge control agent can be used, but in color toners, white or light-colored ones are preferred. When a colored charge control agent is used, it is preferable that the content is small in order to prevent the toner from becoming dull due to the color being mixed with the toner.

[0086] Examples of the charge control agent include nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxyamines, quaternary ammonium salts (including fluorine-modified quaternary ammonium salts), alkylamides, phosphorus simple substances or compounds, tungsten simple substances or compounds, fluorine-based activators, metal salicylate salts, and metal salts of salicylic acid derivatives. Specifically, for example, the nigrosine dye Bontron 03, the quaternary ammonium salt Bontron P-51, the metal-containing azo dye Bontron S-34, the oxynaphthoic acid metal complex E-82, the salicylic acid metal complex E-84, the phenol condensate E-89 (all manufactured by Orient Chemical Industry Co., Ltd.), the quaternary ammonium salt molybdenum complexes TP-302 and TP-415 (all manufactured by Hodogaya Chemical Co., Ltd.), the quaternary ammonium salt Copy Charge PSY VP2038, the triphenylmethane derivative Copy Blue PR, the quaternary ammonium salt Copy Charge NEG VP2036, and the Copy Charge NX. Examples include VP434 (all manufactured by Hoechst), LRA-901, the boron complex LR-147 (manufactured by Nippon Carlit), copper phthalocyanine, perylene, quinacridone, azo pigments, and other polymeric compounds having functional groups such as sulfonic acid groups, carboxyl groups, and quaternary ammonium salts.

[0087] The charge control agent can be melt-kneaded together with the resin, the release agent, and the masterbatch. The amount of the charge control agent used is preferably 0.1 to 10 parts by mass, more preferably 0.2 to 5 parts by mass, per 100 parts by mass of the resin. When the amount of the charge control agent used is within the above range, the chargeability of the toner does not become too high, so the effect of the charge control agent does not decrease, the electrostatic attraction force with the developing roller is maintained at an appropriate level, and the fluidity of the developer and the image density are less likely to decrease. The amount of the charge control agent used can be adjusted appropriately depending on the type of resin used in the toner, the presence or absence of additives used as needed, and the toner production method including the dispersion method.

[0088] <<Other ingredients>> The toner may also contain other components as appropriate depending on the purpose. Examples of other components include a flowability improver, a cleaning property improver, a magnetic material, and a metal soap.

[0089] The flowability improver refers to a substance that is used to treat the surface of a component that can be contained in the toner to increase hydrophobicity, thereby making it possible to prevent deterioration of flowability and charging characteristics even under high humidity conditions. Examples of the flow improver include silane coupling agents, silylating agents, silane coupling agents having a fluorinated alkyl group, organic titanate coupling agents, aluminum coupling agents, silicone oils, and modified silicone oils. The cleaning property improver is used to remove the developer remaining on the electrostatic latent image bearing member or intermediate transfer member after transfer.

[0090] Examples of the cleaning property improver include polymer fine particles produced by soap-free emulsion polymerization, such as fatty acid metal salts of zinc stearate, calcium stearate, and stearic acid, polymethyl methacrylate fine particles, and polystyrene fine particles. The polymer fine particles preferably have a relatively narrow peak width in the particle size distribution, and suitably have a mass average particle size of 0.01 to 1 μm.

[0091] The magnetic material is not particularly limited and can be appropriately selected from known materials depending on the purpose, and examples thereof include iron powder, magnetite, ferrite, etc. Among these, a material having a color tone that is unlikely to be mixed with the toner is preferred, a light-colored material is more preferred, and a white material is even more preferred.

[0092] (Toner manufacturing method) The method for producing the toner in the present invention is not particularly limited, and the toner can be produced by a melt-kneading pulverization method and a polymerization method, a polyaddition reaction method using an isocyanate group-containing prepolymer, a method of dissolving in a solvent and removing the solvent followed by pulverization, or a melt spray method. For example, methods that can be used include a melt-kneading method, a polymerization method (suspension polymerization method, emulsion polymerization method) in which a monomer composition containing a specific crystalline polymer and a polymerizable monomer is directly polymerized in an aqueous phase, a polyaddition reaction method in which a composition containing a specific crystalline polymer and an isocyanate group-containing prepolymer is directly elongated / crosslinked with amines in an aqueous phase, and a method in which the material is dissolved in a solvent, desolvated, and then pulverized. In the toner of the present invention, the main component of the resin is preferably a polyester resin.

[0093] In the melt-kneading pulverization method, suitable devices for melting and kneading the toner include, for example, a batch-type two-roll mixer, a Banbury mixer, a continuous twin-screw extruder, a KTK-type twin-screw extruder manufactured by Kobe Steel, Ltd., a TEM-type twin-screw extruder manufactured by Toshiba Machine Co., Ltd., a twin-screw extruder manufactured by KCK Corporation, a PCM-type twin-screw extruder manufactured by Ikegai Iron Works, a KEX-type twin-screw extruder manufactured by Kurimoto Iron Works, a continuous single-screw kneader, and a Ko-Kneader manufactured by Buss.

[0094] In the above-mentioned polymerization method and polyaddition reaction method using an isocyanate group-containing prepolymer, it is essential to apply mechanical energy to the aqueous phase to forcibly emulsify (form droplets). Examples of the means for applying mechanical energy include means for applying strong stirring or ultrasonic vibration energy using a homomixer, ultrasonic waves, a Manton-Gaulin mixer, etc.

[0095] The toner raw materials are coarsely pulverized using a hammer mill, a rotoplex, or the like, and then further pulverized to an appropriate size using a fine pulverizer using a jet stream or a mechanical fine pulverizer, etc. It is preferable that the pulverized material is pulverized to a mass average particle size of 3 to 15 μm. Furthermore, it is preferable that the particle size of the pulverized material is adjusted to a mass average particle size of 5 to 20 μm using an air classifier, etc.

[0096] The softening temperature of the toner (T1 / 2: the temperature at which half of the sample flows out when heated and under a predetermined load) determined using a flow tester is preferably 115 to 140°C. From the viewpoint of toner storage stability, the glass transition temperature (Tg) of the toner is preferably 55 to 70°C, more preferably 57 to 70°C. If the toner Tg is 55°C or higher, the toner is less likely to deteriorate in a high-temperature atmosphere and offset is less likely to occur during fixing. Furthermore, if the toner Tg is 70°C or lower, the fixing ability of the toner is less likely to decrease.

[0097] The method for coating the toner base particles with the external additives involves mixing and stirring the toner base particles with the external additives using a mixer, thereby disintegrating the external additives and coating the surfaces of the toner base particles with the external additives. By uniformly and firmly adhering the external additives to the toner base particles, the durability of the toner can be improved.

[0098] (developer) The developer using the toner of the present invention may be either a one-component developer or a two-component developer. The two-component developer contains the toner of the present invention and a carrier. The carrier is not particularly limited and can be appropriately selected depending on the purpose, but is preferably one having a core material and a resin layer covering the core material.

[0099] The material for the core material is not particularly limited and can be appropriately selected depending on the purpose. For example, manganese-strontium (Mn-Sr)-based materials and manganese-magnesium (Mn-Mg)-based materials with a magnetic field of 50 emu / g to 90 emu / g are preferred. From the viewpoint of ensuring image density, highly magnetic materials such as iron powder (100 emu / g or more) and magnetite (75 emu / g to 120 emu / g) are preferred. Furthermore, weakly magnetic materials such as copper-zinc (Cu-Zn)-based materials (30 emu / g to 80 emu / g) are preferred because they can weaken the contact of the toner with the photoreceptor in a spiked state, which is advantageous for achieving high image quality. These materials may be used alone or in combination.

[0100] The volume average particle size of the core material is preferably 25 μm or more and 200 μm or less.

[0101] The material for the resin layer is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include amino resins, polyvinyl resins, polystyrene resins, halogenated olefin resins, polyester resins, polycarbonate resins, polyethylene resins, polyvinyl fluoride resins, polyvinylidene fluoride resins, polytrifluoroethylene resins, polyhexafluoropropylene resins, copolymers of vinylidene fluoride and an acrylic monomer, copolymers of vinylidene fluoride and vinyl fluoride, fluoro terpolymers such as terpolymers of tetrafluoroethylene, vinylidene fluoride and a non-fluorinated monomer, silicone resins, etc. These may be used alone or in combination of two or more.

[0102] The mixing ratio of the toner and carrier in the two-component developer is preferably 2.0% by mass to 12.0% by mass, more preferably 2.5% by mass to 10.0% by mass.

[0103] (Toner storage unit) In this specification, the term "toner storage unit" refers to a unit that has a function of storing toner and stores toner. Examples of the toner storage unit include a toner storage container, a developing unit, a developing device, and a process cartridge. The toner storage container refers to a container that stores toner. The developing unit and developing device refer to a device having means for storing toner and developing. The process cartridge is a cartridge that integrates at least an image carrier and a developing unit, contains toner, and is detachably mountable to an image forming apparatus. The process cartridge may further include one or more of a charging unit, an exposure unit, and a cleaning unit. The toner storage unit of the present invention stores the toner of the present invention. By mounting the toner storage unit of the present invention in an image forming apparatus and forming an image using the toner of the present invention, it is possible to obtain an excellent image with excellent low-temperature fixing properties and heat-resistant storage properties, and with few abnormalities.

[0104] (Process cartridge) A process cartridge according to one embodiment of the present invention includes at least an electrostatic latent image carrier that carries an electrostatic latent image, and a developing unit. The developing unit can form a toner image by developing the electrostatic latent image carried on the electrostatic latent image carrier with the toner of the present invention.

[0105] The process cartridge may further include other means as required, such as a charging means, an exposure means, a transfer means, a cleaning means, and a discharging means.

[0106] The developing means has at least a developer container that contains the toner or developer of the present invention, and a developer carrier that carries and transports the toner or developer contained in the developer container. The developing means may further include a layer thickness regulating member for regulating the thickness of the toner layer carried on the developer carrier.

[0107] The process cartridge of the present invention is preferably detachably mountable to the main body of an image forming apparatus such as various electrophotographic apparatuses, facsimiles, printers, and the like.

[0108] (Image forming method and image forming apparatus) The image forming apparatus of the present invention includes an electrostatic latent image carrier, an electrostatic latent image forming unit that forms an electrostatic latent image on the electrostatic latent image carrier, a developing unit that develops the electrostatic latent image formed on the electrostatic latent image carrier with toner to form a toner image, a transfer unit that transfers the toner image formed on the electrostatic latent image carrier to a recording medium, and a fixing unit that fixes the toner image transferred to the recording medium to the recording medium, wherein the toner is the toner of the present invention. The image forming apparatus of the present invention may further include other means such as a discharging means, a cleaning means, a recycling means, and a control means, if necessary.

[0109] The image forming method of the present invention includes an electrostatic latent image forming step of forming an electrostatic latent image on an electrostatic latent image carrier, a developing step of developing the electrostatic latent image formed on the electrostatic latent image carrier with toner to form a toner image, a transfer step of transferring the toner image formed on the electrostatic latent image carrier to a recording medium, and a fixing step of fixing the toner image transferred to the recording medium to the recording medium, wherein the toner is the toner of the present invention. The image forming method of the present invention may further include other steps such as a charge eliminating step, a cleaning step, a recycling step, and a control step, if necessary.

[0110] The method for producing a printed matter of the present invention is a method for producing a printed matter performed by the image forming apparatus of the present invention, and is performed using the toner of the present invention.

[0111] <Electrostatic latent image forming process and electrostatic latent image forming means> The electrostatic latent image forming step is a step of forming an electrostatic latent image on an electrostatic latent image bearing member. The electrostatic latent image forming means is a means for forming an electrostatic latent image on an electrostatic latent image carrier. The electrostatic latent image forming step is preferably carried out by the electrostatic latent image forming means.

[0112] The electrostatic latent image carrier (hereinafter sometimes referred to as "electrophotographic photoreceptor" or "photoreceptor") is not particularly limited in terms of material, shape, structure, size, etc., and can be appropriately selected from known ones.

[0113] The electrostatic latent image bearing member preferably has a drum shape. Examples of materials for the electrostatic latent image carrier include inorganic photoconductors such as amorphous silicon and selenium, and organic photoconductors (OPC) such as polysilane and phthalopolymethine. Among these, organic photoconductors (OPC) are preferred because they can produce higher-resolution images.

[0114] Examples of the organic photoreceptor include a laminated photoreceptor having a laminated structure in which a layer (charge generation layer) in which a charge generation material such as metal-free phthalocyanine or titanyl phthalocyanine is dispersed in a binder resin and a layer (charge transport layer) in which a charge transport material is dispersed in a binder resin are stacked on a support such as an aluminum drum, and a single-layer photoreceptor having a single-layer photosensitive layer in which both a charge generation material and a charge transport material are dispersed in a binder resin on a support. In the single-layer photoreceptor, a hole transport material and an electron transport material can also be added to the photosensitive layer as charge transport materials. An undercoat layer may be provided between the support and the multilayer charge generating layer or the single-layer photosensitive layer.

[0115] In the electrostatic latent image forming step, the electrostatic latent image can be formed, for example, by uniformly charging the surface of the electrostatic latent image bearing member by the electrostatic latent image forming means, and then exposing the surface to light in an imagewise manner.

[0116] The electrostatic latent image forming means can include, for example, at least a charging means (charger) that uniformly charges the surface of the electrostatic latent image carrier, and an exposure means (exposure device) that imagewise exposes the surface of the electrostatic latent image carrier. The charging can be carried out, for example, by applying a voltage to the surface of the electrostatic latent image bearing member using the charger. The charger is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include a known contact charger equipped with a conductive or semiconductive roll, brush, film, rubber blade, etc., and a non-contact charger utilizing corona discharge such as a corotron or scorotron.

[0117] The charger is preferably one that is disposed in contact with or not in contact with the electrostatic latent image bearing member and charges the surface of the electrostatic latent image bearing member by applying DC and AC voltages in a superimposed manner. The charger is preferably a charging roller arranged close to the electrostatic latent image carrier without contacting the electrostatic latent image carrier via a gap tape, and the surface of the electrostatic latent image carrier is preferably charged by applying a DC voltage and an AC voltage superimposed on the charging roller.

[0118] The exposure can be carried out, for example, by exposing the surface of the electrostatic latent image bearing member to light in an imagewise manner using the exposure unit. The exposure device is not particularly limited as long as it can expose the surface of the electrostatic latent image carrier charged by the charger in the form of an image to be formed, and can be appropriately selected depending on the purpose. Examples of the exposure device include various exposure devices such as a copying optical system, a rod lens array system, a laser optical system, and a liquid crystal shutter optical system. In the image forming apparatus and image forming method of the present invention, a backlight system in which imagewise exposure is performed from the back side of the electrostatic latent image bearing member may be adopted.

[0119] <Developing step and developing means> The developing step is a step of developing the electrostatic latent image with the toner of the present invention to form a toner image. The developing means is a means for developing the electrostatic latent image with the toner of the present invention to form a toner image. The developing step is preferably carried out by the developing means. In the developing step, the toner image can be formed by, for example, developing the electrostatic latent image with the toner, and can be performed by the developing unit.

[0120] The developing means preferably has at least a developing unit or developing device that contains the toner and can apply the toner to the electrostatic latent image in a contact or non-contact manner, and more preferably a developing unit or developing device that is equipped with a toner container. The developing unit or developer may be for a single color or for multiple colors. The developing unit or developing device preferably includes, for example, a device having a stirrer that charges the toner by friction stirring, and a rotatable magnet roller. The development method may be a premix development method, in which a premix developer in which toner and carrier are mixed in advance is replenished. In the premix development method, the excess carrier in the developing device is discharged as excess developer. This gradually refreshes the developer in the developing device. This can extend the replacement cycle due to developer deterioration and eliminate the effort required for developer replacement.

[0121] <Transfer process and transfer means> The transfer step is a step of transferring the toner image onto a recording medium. The transfer unit is a unit for transferring the toner image onto a recording medium. The transfer step is preferably carried out by the transfer means. In the transfer step, a preferred embodiment is one in which a toner image is primarily transferred onto an intermediate transfer member, and then the toner image is secondarily transferred onto the recording medium.

[0122] Furthermore, it is more preferable that the transfer step uses two or more colors of toner, preferably full-color toner, as the toner, and includes a first transfer step in which the toner image is transferred onto an intermediate transfer body to form a composite transfer image, and a second transfer step in which the composite transfer image is transferred onto a recording medium. The transfer means used in the transfer step (the first transfer means in the first transfer step, and the second transfer means in the second transfer step) preferably has at least a transfer device that peels and charges the toner image formed on the electrostatic latent image carrier (photosensitive member) onto the recording medium. The number of transfer means may be one or more.

[0123] Examples of the transfer device include a corona transfer device using corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, and an adhesive transfer device. The recording medium is not particularly limited and can be appropriately selected from known recording media (recording paper).

[0124] <Fixing process and fixing means> The fixing step is a step of fixing the toner image transferred onto the recording medium. The fixing unit is a unit for fixing the toner image transferred onto the recording medium. The fixing step is preferably carried out by the fixing means. The fixing step may be carried out for each color developer each time it is transferred onto the recording medium by the fixing means, or may be carried out simultaneously for each color developer in a stacked state.

[0125] The fixing means is not particularly limited and can be appropriately selected depending on the purpose, but known heating and pressurizing means are suitable. Examples of the heating and pressurizing means include a combination of a heating roller and a pressure roller, and a combination of a heating roller, a pressure roller and an endless belt.

[0126] <Other steps and other means> The charge removal step is a step of removing electricity by applying a charge removal bias to the electrostatic latent image bearing member, and can be suitably performed by a charge removal unit. The discharging means is not particularly limited as long as it can apply a discharging bias to the electrostatic latent image bearing member, and can be appropriately selected from known discharging devices, and a suitable example is a discharging lamp.

[0127] The cleaning step is a step of removing the toner remaining on the electrostatic latent image bearing member, and can be suitably carried out by a cleaning means. The cleaning means is not particularly limited as long as it can remove the toner remaining on the electrostatic latent image carrier, and can be appropriately selected from known cleaners. Suitable examples include magnetic brush cleaners, electrostatic brush cleaners, magnetic roller cleaners, blade cleaners, brush cleaners, and web cleaners.

[0128] The recycling step is a step of recycling the toner removed in the cleaning step to the developing unit, and can be suitably performed by a recycling means. The recycling means is not particularly limited, and examples thereof include known transport means.

[0129] The control step is a step of controlling each of the steps, and each of the steps can be suitably carried out by a control means. The control means is not particularly limited as long as it can control the movement of each of the means, and can be appropriately selected depending on the purpose. Examples of the control means include devices such as a sequencer and a computer.

[0130] <Example of image forming apparatus and image forming method> FIG. 1 is a schematic explanatory diagram showing an example of a part of an image forming apparatus according to one embodiment of the present invention. The image forming apparatus 100A includes a photosensitive drum 10, a charging roller 20, an exposure device, a developing device 40, an intermediate transfer belt 50, a cleaning device 60 having a cleaning blade, and a discharging lamp .

[0131] The intermediate transfer belt 50 is an endless belt stretched by three rollers 51 arranged inside, and can move in the direction of the arrow in Figure 1. Some of the three rollers 51 also function as transfer bias rollers that can apply a transfer bias (primary transfer bias) to the intermediate transfer belt 50. A cleaning device 90 having a cleaning blade is arranged near the intermediate transfer belt 50. Furthermore, a transfer roller 80 that can apply a transfer bias (secondary transfer bias) to transfer a toner image onto transfer paper 95 is arranged opposite the intermediate transfer belt 50.

[0132] In addition, a corona charging device 58 for applying an electric charge to the toner image transferred to the intermediate transfer belt 50 is arranged around the intermediate transfer belt 50, between the contact point between the photosensitive drum 10 and the intermediate transfer belt 50 and the contact point between the intermediate transfer belt 50 and the transfer paper 95, in the direction of rotation of the intermediate transfer belt 50.

[0133] The developing device 40 is composed of a developing belt 41 and a black developing unit 45K, a yellow developing unit 45Y, a magenta developing unit 45M, and a cyan developing unit 45C, which are arranged around the developing belt 41 and contain the toner of the present invention. The developing units 45K, 45Y, 45M, and 45C, which contain the toner of the present invention, each include a developer container 42K, 42Y, 42M, and 42C, developer supply rollers 43K, 43Y, 43M, and 43C, and developing rollers (developer carriers) 44K, 44Y, 44M, and 44C. The developing belt 41 is an endless belt stretched over multiple belt rollers and can move in the direction indicated by the arrow in FIG. 1. Furthermore, a portion of the developing belt 41 contacts the photosensitive drum 10.

[0134] Next, a portion of an example of a method for forming an image using the toner of the present invention using the image forming apparatus 100A will be described. First, the surface of the photosensitive drum 10 is uniformly charged using the charging roller 20, and then the photosensitive drum 10 is exposed to exposure light L using an exposure device to form an electrostatic latent image. Next, the electrostatic latent image formed on the photosensitive drum 10 is developed with toner supplied from the developing device 40 to form a toner image. Furthermore, the toner image formed on the photosensitive drum 10 is transferred (primary transfer) onto the intermediate transfer belt 50 by a transfer bias applied from the roller 51, and then transferred (secondary transfer) onto the transfer paper 95 by a transfer bias applied from the transfer roller 80. Meanwhile, the photosensitive drum 10 from which the toner image has been transferred onto the intermediate transfer belt 50 has residual toner removed by the cleaning device 60, and is then discharged by the discharge lamp 70. In this embodiment, an elastic intermediate transfer belt can also be used as the intermediate transfer belt 50. As the elastic intermediate transfer belt, for example, one in which a flexible elastic layer is laminated on a rigid base layer that is relatively flexible can be used. In order to prevent the intermediate transfer belt 50 from meandering, a guide member for preventing deviation may be provided on the inner peripheral surface of the intermediate transfer belt 50 .

[0135] 2 is a schematic diagram showing another example of a part of an image forming apparatus according to one embodiment of the present invention. Image forming apparatus 100B has the same configuration as image forming apparatus 100A, except that it does not have developing belt 41 and has black developing unit 45K, yellow developing unit 45Y, magenta developing unit 45M, and cyan developing unit 45C arranged directly opposite each other around photoconductor drum 10.

[0136] 3 is a schematic diagram showing an example of an image forming apparatus according to an embodiment of the present invention. Image forming apparatus 100C is a tandem color image forming apparatus, and includes a copying machine main body 150, a paper feed table 200, a scanner 300, and an automatic document feeder (ADF) 400.

[0137] Intermediate transfer belt 50, located in the center of copying machine main body 150, is an endless belt stretched around three rollers 14, 15, and 16, and can move in the direction of the arrow in Figure 3. Near roller 15, a cleaning device 17 is disposed, which has a cleaning blade for removing toner remaining on intermediate transfer belt 50 after a toner image has been transferred to recording paper. Opposite intermediate transfer belt 50 stretched around rollers 14 and 15, yellow, cyan, magenta, and black image forming units 120Y, 120C, 120M, and 120K are arranged in parallel along the conveyance direction.

[0138] An exposure device 21 is also disposed near the image forming unit 120. Furthermore, a secondary transfer belt 24 is disposed on the side of the intermediate transfer belt 50 opposite to the side where the image forming unit 120 is disposed. The secondary transfer belt 24 is an endless belt stretched over a pair of rollers 23, and the recording paper transported on the secondary transfer belt 24 and the intermediate transfer belt 50 can come into contact with each other between the rollers 16 and 23.

[0139] Also, near the secondary transfer belt 24 is disposed a fixing device 25 that includes a fixing belt 26, which is an endless belt stretched over a pair of rollers, and a pressure roller 27 that is positioned so as to be pressed against the fixing belt 26. Also, near the secondary transfer belt 24 and the fixing device 25 is disposed a sheet inverting device 28 for inverting the recording paper when forming images on both sides of the recording paper.

[0140] Next, an example of a method for forming a full-color image using the toner of the present invention and the image forming apparatus 100C will be described. First, a color original is placed on the platen 130 of the automatic document feeder (ADF) 400, or the automatic document feeder 400 is opened and the color original is placed on the contact glass 32 of the scanner 300, and the automatic document feeder 400 is closed.

[0141] When the start switch is pressed, if an original is set on the automatic document feeder 400, the original is transported and moved onto the contact glass 32, and on the other hand, if the original is set on the contact glass 32, the scanner 300 is driven and the first traveling body 33 equipped with a light source and the second traveling body 34 equipped with a mirror start traveling. At this time, light irradiated from the first traveling body 33 is reflected from the surface of the original, reflected by the second traveling body 34, and then received by the reading sensor 36 via the imaging lens 35, thereby reading the original and obtaining image information of black, yellow, magenta, and cyan.

[0142] The image information for each color is transmitted to the image forming means 18 in the image forming unit 120 for each color, and a toner image of each color is formed.

[0143] Fig. 4 is a schematic diagram showing another example of a portion of an image forming apparatus according to an embodiment of the present invention. As shown in Fig. 4, each of the image forming units 120 for each color includes a photosensitive drum 10, a charging roller 160 that uniformly charges the photosensitive drum 10, an exposure device that exposes the photosensitive drum 10 to exposure light L based on image information for each color to form an electrostatic latent image for each color, a developing device 61 that develops the electrostatic latent image with a developer for each color to form a toner image for each color, a transfer roller 62 that transfers the toner image onto the intermediate transfer belt 50, a cleaning device 63 having a cleaning blade, and a discharging lamp 64. The developing device 61 corresponds to the toner storage unit in this specification.

[0144] The toner images of each color formed by the image forming units 120 of each color shown in Figure 3 are sequentially transferred (primary transfer) onto the intermediate transfer belt 50, which is stretched and moves around rollers 14, 15, and 16, and are superimposed to form a composite toner image.

[0145] On the other hand, in the paper feed table 200, one of the paper feed rollers 142 is selectively rotated to feed recording paper from one of the paper feed cassettes 144 provided in multiple stages in the paper bank 143, which is separated one sheet at a time by the separation roller 145 and sent to the paper feed path 146, and then conveyed by the conveyance roller 147 and guided to the paper feed path 148 in the copying machine main body 150, where it is stopped by hitting the registration roller 49. Alternatively, the paper feed roller is rotated to feed recording paper from the manual feed tray 54, which is separated one sheet at a time by the separation roller 52 and guided to the manual feed path 53, where it is stopped by hitting the registration roller 49.

[0146] The registration roller 49 is generally grounded when in use, but may be used with a bias applied to it in order to remove paper dust from the recording paper.

[0147] Next, the registration rollers 49 are rotated in synchronization with the composite toner image formed on the intermediate transfer belt 50, thereby feeding the recording paper between the intermediate transfer belt 50 and the secondary transfer belt 24, and the composite toner image is transferred (secondary transfer) onto the recording paper. Any toner remaining on the intermediate transfer belt 50 after the composite toner image has been transferred is removed by the cleaning device 17. It is also possible to provide a collecting means for receiving the toner etc. removed by the cleaning device 17. A dish-shaped tray or the like can be used as the collecting means.

[0148] The recording paper onto which the composite toner image has been transferred is transported by secondary transfer belt 24, and then the composite toner image is fixed by fixing device 25. Next, the transport path of the recording paper is switched by switching claw 55, and the recording paper is discharged onto paper discharge tray 57 by discharge rollers 56. Alternatively, the transport path of the recording paper is switched by switching claw 55, the sheet is inverted by sheet inverting device 28, an image is formed on the back side in the same manner, and then the recording paper is discharged onto paper discharge tray 57 by discharge rollers 56. [Example]

[0149] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. "Parts" refers to "parts by mass" unless otherwise specified.

[0150] (Preparation of inorganic external additives) <Preparation of inorganic external additive 1) 100 g of hydrophilic silica particles (Aerosil 200, manufactured by Nippon Aerosil Co., Ltd., average primary particle diameter 12 nm) were dispersed in 2 L of water and heated to 85°C. Next, an aluminum chloride aqueous solution was added in an amount equivalent to 10% by mass of Al2O3 relative to the silica particles, and the pH was adjusted to 5.5 with aqueous sodium hydroxide. The mixture was then stirred for 30 minutes, filtered, and the residue on the filter was washed with water to obtain a washed cake. Next, this washed cake was dried at 120°C and then pulverized in a media-type fine grinder. Finally, 40 g of the obtained powder was placed in a small mixer, and 10.6 g of isobutyltrimethoxysilane was added. The mixture was mixed for 15 minutes and then re-dried at 120°C to produce inorganic external additive 1 (average particle diameter 12 nm). The average particle diameter is the number-average particle diameter (the same applies below).

[0151] <Preparation of inorganic external additive 2> 100 g of hydrophilic silica particles (Aerosil 200: manufactured by Nippon Aerosil Co., Ltd., average primary particle diameter 12 nm) were dispersed in 2 L of water and heated to 85 °C. Next, an aluminum chloride aqueous solution was added in an amount equivalent to 10% by mass of Al2O3 relative to the silica particles, and the pH was adjusted to 5.5 with aqueous sodium hydroxide. The mixture was then stirred for 30 minutes, filtered, and the residue on the filter was washed with water to obtain a washed cake. Next, this washed cake was dried at 120 °C and then pulverized in a media-type fine grinder. Finally, 40 g of the obtained powder was placed in a small mixer, and 11.4 g of isobutyltrimethoxysilane was added and mixed for 15 minutes. After that, it was re-dried at 120 °C to produce inorganic external additive 2 (average particle size 12 nm).

[0152] <Preparation of inorganic external additive 3> 100 g of hydrophilic silica particles (Aerosil 200, manufactured by Nippon Aerosil Co., Ltd., average primary particle diameter 12 nm) were dispersed in 2 L of water and heated to 85°C. Next, an aluminum chloride aqueous solution was added in an amount equivalent to 10% by mass of Al2O3 relative to the silica particles, and the pH was adjusted to 5.5 with aqueous sodium hydroxide solution. The mixture was then stirred for 30 minutes, filtered, and the residue on the filter was washed with water to obtain a washed cake. Next, this washed cake was dried at 120°C and then pulverized in a media-type fine grinder. Finally, 40 g of the obtained powder was placed in a small mixer, and 10.3 g of isobutyltrimethoxysilane was added and mixed for 15 minutes. After that, it was re-dried at 120°C to produce inorganic external additive 3 (average particle size 12 nm).

[0153] <Preparation of inorganic external additive 4> 100 g of hydrophilic silica particles (Aerosil 200, manufactured by Nippon Aerosil Co., Ltd., average primary particle diameter 12 nm) were dispersed in 2 L of water and heated to 85°C. Next, an aluminum chloride aqueous solution was added in an amount equivalent to 10% by mass of Al2O3 relative to the silica particles, and the pH was adjusted to 5.5 with aqueous sodium hydroxide. The mixture was then stirred for 30 minutes, filtered, and the residue on the filter was washed with water to obtain a washed cake. Next, this washed cake was dried at 120°C and then pulverized in a media-type fine grinder. Finally, 40 g of the obtained powder was placed in a small mixer, and 11.7 g of isobutyltrimethoxysilane was added and mixed for 15 minutes. After that, it was re-dried at 120°C to produce inorganic external additive 4 (average particle size 12 nm).

[0154] <Preparation of inorganic external additive 5> 100 g of hydrophilic silica particles (Aerosil 200: manufactured by Nippon Aerosil Co., Ltd., average primary particle diameter 12 nm) were dispersed in 2 L of water and heated to 85 ° C. Next, a zinc chloride aqueous solution was added in an amount equivalent to 10% by mass of ZnO relative to the silica particles, and the pH was adjusted to 8.0 with a sodium hydroxide aqueous solution. The mixture was then stirred for 30 minutes, filtered, and the residue on the filter was washed with water to obtain a washed cake. Next, this washed cake was dried at 120 ° C and then pulverized in a media-type fine grinder. Finally, 40 g of the obtained powder was placed in a small mixer, and 10.6 g of isobutyltrimethoxysilane was added and mixed for 15 minutes. After that, it was re-dried at 120 ° C to produce inorganic external additive 5 (average particle size 12 nm).

[0155] <Preparation of inorganic external additive 6> 100 g of hydrophilic silica particles (Aerosil 200: manufactured by Nippon Aerosil Co., Ltd., average primary particle diameter 12 nm) were dispersed in 2 L of water and heated to 85 ° C. Next, an aqueous magnesium chloride solution was added in an amount equivalent to 10% by mass of the silica particles in terms of MgO, and the mixture was adjusted to pH 5.0 with an aqueous sodium hydroxide solution. The mixture was then stirred for 30 minutes, filtered, and the residue on the filter media was washed with water to obtain a washed cake. Next, this washed cake was dried at 120 ° C and then pulverized in a media-type fine grinder. Finally, 40 g of the obtained powder was placed in a small mixer, and 10.6 g of isobutyltrimethoxysilane was added and mixed for 15 minutes. After that, it was re-dried at 120 ° C to produce inorganic external additive 6 (average particle size 12 nm).

[0156] <Preparation of inorganic external additive 7> 100 g of hydrophilic silica particles (Aerosil 200, manufactured by Nippon Aerosil Co., Ltd., average primary particle diameter 12 nm) were dispersed in 2 L of water and heated to 85 ° C. Next, an iron chloride aqueous solution was added in an amount equivalent to 10% by mass of the silica particles in terms of FeO, and the pH was adjusted to 8.5 with aqueous sodium hydroxide. The mixture was then stirred for 30 minutes, filtered, and the residue on the filter was washed with water to obtain a washed cake. Next, this washed cake was dried at 120 ° C and then pulverized in a media-type fine grinder. Finally, 40 g of the obtained powder was placed in a small mixer, and 10.6 g of isobutyltrimethoxysilane was added and mixed for 15 minutes. After that, it was re-dried at 120 ° C to produce inorganic external additive 7 (average particle size 12 nm).

[0157] <Preparation of inorganic external additive 8> 100 g of hydrophilic silica particles (Aerosil 90: manufactured by Nippon Aerosil Co., Ltd., average primary particle diameter 25 nm) were dispersed in 2 L of water and heated to 85°C. Next, an aluminum chloride aqueous solution was added in an amount equivalent to 10% by mass of Al2O3 relative to the silica particles, and the pH was adjusted to 5.5 with aqueous sodium hydroxide. The mixture was then stirred for 30 minutes, filtered, and the residue on the filter was washed with water to obtain a washed cake. Next, this washed cake was dried at 120°C and then pulverized in a media-type fine grinder. Finally, 40 g of the obtained powder was placed in a small mixer, and 10.6 g of isobutyltrimethoxysilane was added and mixed for 15 minutes. After that, it was re-dried at 120°C to produce inorganic external additive 8 (average particle size 25 nm).

[0158] <Preparation of inorganic external additive 9> 100 g of hydrophilic silica particles (Aerosil 300: manufactured by Nippon Aerosil Co., Ltd., average primary particle diameter 8 nm) were dispersed in 2 L of water and heated to 85°C. Next, an aluminum chloride aqueous solution was added in an amount equivalent to 10% by mass of Al2O3 relative to the silica particles, and the pH was adjusted to 5.5 with aqueous sodium hydroxide. The mixture was then stirred for 30 minutes, filtered, and the residue on the filter was washed with water to obtain a washed cake. Next, this washed cake was dried at 120°C and then pulverized in a media-type fine grinder. Finally, 40 g of the obtained powder was placed in a small mixer, and 10.6 g of isobutyltrimethoxysilane was added and mixed for 15 minutes. After that, it was re-dried at 120°C to produce inorganic external additive 9 (average particle size 8 nm).

[0159] <Preparation of inorganic external additive 10> 100 g of hydrophilic silica particles (Aerosil 50, manufactured by Nippon Aerosil Co., Ltd., average primary particle diameter 35 nm) were dispersed in 2 L of water and heated to 85 ° C. Next, an aluminum chloride aqueous solution was added in an amount equivalent to 10 mass % of the silica particles in terms of Al2O3, and the mixture was adjusted to pH 5.5 with aqueous sodium hydroxide. The mixture was then stirred for 30 minutes, filtered, and the residue on the filter media was washed with water to obtain a washed cake. Next, this washed cake was dried at 120 ° C and then pulverized in a media-type fine grinder. Finally, 40 g of the obtained powder was placed in a small mixer, and 10.6 g of isobutyltrimethoxysilane was added and mixed for 15 minutes. After that, it was re-dried at 120 ° C to produce inorganic external additive 10 (average particle size 35 nm).

[0160] <Preparation of inorganic external additive 11> 100 g of hydrophilic silica particles (Aerosil 200: manufactured by Nippon Aerosil Co., Ltd., average primary particle diameter 12 nm) were dispersed in 2 L of water and heated to 85 ° C. Next, an aluminum chloride aqueous solution was added in an amount equivalent to 10 mass % of the silica particles in terms of Al2O3, and the solution was adjusted to pH 5.5 with sodium hydroxide aqueous solution. After stirring for 30 minutes, the mixture was filtered and the residue on the filter media was washed with water to obtain a washed cake. Next, this washed cake was dried at 120 ° C. and then pulverized in a media-type fine grinder to produce inorganic external additive 11 (average particle size 12 nm).

[0161] <Preparation of inorganic external additive 12> 100 g of hydrophilic silica particles (Aerosil 200: manufactured by Nippon Aerosil Co., Ltd., average primary particle diameter 12 nm) were dispersed in 2 L of water and heated to 85 °C. Next, an aluminum chloride aqueous solution was added in an amount equivalent to 10% by mass of Al2O3 relative to the silica particles, and the pH was adjusted to 5.5 with aqueous sodium hydroxide. The mixture was then stirred for 30 minutes, filtered, and the residue on the filter was washed with water to obtain a washed cake. Next, this washed cake was dried at 120 °C and then pulverized in a media-type fine grinder. Finally, 40 g of the obtained powder was placed in a small mixer, and 12 g of isobutyltrimethoxysilane was added and mixed for 15 minutes. After that, it was re-dried at 120 °C to produce inorganic external additive 12 (average particle size 12 nm).

[0162] Details of the inorganic external additives obtained are shown in Table 1. The volume resistivity values ​​in Table 1 were measured using inorganic external additives 1 to 12 as the test samples as follows. First, a cell consisting of a fluororesin container containing two electrodes with a surface area of ​​2.5 cm x 4 cm, spaced 0.2 cm apart, was filled with the test sample between the two electrodes. The sample was then dropped from a height of 1 cm and tapped 10 times at a tapping speed of 30 times per minute. Next, a DC voltage of 1,000 V was applied between the two electrodes containing the test sample, and the resistance value r [Ω] after 30 seconds was measured using a High Resistance Meter 4329A (Yokogawa Hewlett-Packard Co., Ltd.). The volume resistivity [Ω·cm] of the sample was calculated by inputting the measured resistance value r into the following equation: r×(2.5×4) / 0.2...formula

[0163] [Table 1]

[0164] (Preparation of toner base particles) <Preparation of Toner Base Particles 1> -Prescription- Amorphous polyester resin 1: 86.4 parts Crystalline polyester resin 1: 4.8 parts Aromatic petroleum resin 1 (FTR-2140: manufactured by Mitsui Chemicals, Inc.): 4.8 parts Hydrocarbon wax 1 (Sasol Wax C80: manufactured by Sasol Corporation): 4.0 parts Carbon black (Mitsubishi Chemical #44): 10 parts

[0165] According to the above recipe, the toner raw materials were premixed using a Henschel mixer (FM20B, manufactured by Mitsui Miike Chemical Engineering Co., Ltd.), and then melted and kneaded at 120°C in a twin-screw kneader (PCM-30, manufactured by Ikegai Iron Works Co., Ltd.). The resulting kneaded material was rolled to a thickness of 2.7 mm using rollers, cooled to room temperature using a belt cooler, and coarsely pulverized to 200 μm to 300 μm using a hammer mill. Next, the mixture was finely pulverized using a supersonic jet pulverizer Labojet (manufactured by Nippon Pneumatic Mfg. Co., Ltd.), and then classified using an air classifier (MDS-I, manufactured by Nippon Pneumatic Mfg. Co., Ltd.) while appropriately adjusting the louver opening to obtain a weight average particle size of 5.8±0.2 μm, thereby obtaining toner base particles 1.

[0166] The above amorphous polyester resin 1 was obtained as follows. The monomer species shown in Table 2 below and tetrabutoxy titanate as a condensation catalyst were placed in a reaction vessel equipped with a condenser, a stirrer, and a nitrogen inlet tube, and the reaction was carried out at 230°C for 6 hours under a nitrogen stream while distilling off the water produced. Next, the reaction was carried out for 1 hour under a reduced pressure of 5 mmHg to 20 mmHg, yielding amorphous polyester resin 1. In Table 2, the "25 mol %" shown for bisphenol A (2,2) ethylene oxide indicates the proportion of the alcohol component when the acid component and alcohol component are 50 mol % and 50 mol %, respectively.

[0167] [Table 2]

[0168] The above crystalline polyester resin 1 was obtained as follows. Fumaric acid and 1,6-hexanediol were charged into a 5 L four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple so that the OH / COOH ratio of the mixture was 0.9, and reacted with titanium tetraisopropoxide (500 ppm relative to the resin components) at 180°C for 10 hours. The mixture was then heated to 200°C and reacted for 3 hours, and then further reacted at a pressure of 8.3 kPa for 2 hours to obtain crystalline polyester resin 1 with a melting point of 103°C.

[0169] <Preparation of Toner Base Particles 2> Toner base particles 2 were prepared by carrying out a spheronization treatment using hot air in the preparation of toner base particles 1.

[0170] <Preparation of Toner Base Particles 3> -Prescription- Amorphous polyester resin 1: 91.2 parts Aromatic petroleum resin 1: 4.8 parts Hydrocarbon wax 1: 4.0 parts Carbon black (Mitsubishi Chemical #44): 10 parts

[0171] According to the above recipe, the toner raw materials were premixed using a Henschel mixer (FM20B, manufactured by Mitsui Miike Chemical Engineering Co., Ltd.), and then melted and kneaded at 120°C in a twin-screw kneader (PCM-30, manufactured by Ikegai Iron Works Co., Ltd.). The resulting kneaded material was rolled to a thickness of 2.7 mm using rollers, cooled to room temperature using a belt cooler, and coarsely pulverized to 200 μm to 300 μm using a hammer mill. Next, the mixture was finely pulverized using a supersonic jet pulverizer Labojet (manufactured by Nippon Pneumatic Mfg. Co., Ltd.), and then classified using an air classifier (MDS-I, manufactured by Nippon Pneumatic Mfg. Co., Ltd.) while appropriately adjusting the louver opening to obtain a weight average particle size of 5.8±0.2 μm, thereby obtaining toner base particles 3.

[0172] <Preparation of Toner Base Particles 4> -Prescription- Amorphous polyester resin 1: 91.2 parts Crystalline polyester resin 1: 4.8 parts Hydrocarbon wax 1: 4.0 parts Carbon black (Mitsubishi Chemical #44): 10 parts

[0173] According to the above recipe, the toner raw materials were premixed using a Henschel mixer (FM20B, manufactured by Mitsui Miike Chemical Engineering Co., Ltd.), and then melted and kneaded at 120°C in a twin-screw kneader (PCM-30, manufactured by Ikegai Iron Works Co., Ltd.). The resulting kneaded material was rolled to a thickness of 2.7 mm using rollers, cooled to room temperature using a belt cooler, and coarsely pulverized to 200 μm to 300 μm using a hammer mill. Next, the mixture was finely pulverized using a supersonic jet pulverizer Labojet (manufactured by Nippon Pneumatic Mfg. Co., Ltd.), and then classified using an air classifier (MDS-I, manufactured by Nippon Pneumatic Mfg. Co., Ltd.) while appropriately adjusting the louver opening to obtain a weight average particle size of 5.8±0.2 μm, thereby obtaining toner base particles 4.

[0174] <Preparation of Toner Base Particles 5> -Prescription- Amorphous polyester resin 1: 86.4 parts Crystalline polyester resin 1: 4.8 parts Aromatic petroleum resin 1: 4.8 parts Ester wax (WE-10: NOF Corp.): 4.0 parts Carbon black (Mitsubishi Chemical #44): 10 parts

[0175] According to the above recipe, the toner raw materials were premixed using a Henschel mixer (FM20B, manufactured by Mitsui Miike Chemical Engineering Co., Ltd.), and then melted and kneaded at 120°C in a twin-screw kneader (PCM-30, manufactured by Ikegai Iron Works Co., Ltd.). The resulting kneaded material was rolled to a thickness of 2.7 mm using a roller, cooled to room temperature using a belt cooler, and coarsely pulverized to 200 μm to 300 μm using a hammer mill. Next, the mixture was finely pulverized using a supersonic jet pulverizer Labojet (manufactured by Nippon Pneumatic Mfg. Co., Ltd.), and then classified using an air classifier (MDS-I, manufactured by Nippon Pneumatic Mfg. Co., Ltd.) while appropriately adjusting the louver opening to obtain a weight average particle size of 5.8±0.2 μm, thereby obtaining toner base particles 5.

[0176] Details of the obtained toner base particles are shown in Table 3.

[0177] [Table 3]

[0178] (Examples 1 to 14, Comparative Examples 1 to 3) Toners 1 to 17 were prepared by mixing 100 parts by mass of toner base particles with 1 part by mass of HDK-2000 (Clariant) hydrophobic silica particles and 0.5 parts by mass of an inorganic external additive in a Henschel mixer. Table 4 shows the types of toner base particles and inorganic external additives used.

[0179] [Table 4]

[0180] (Preparation of Toner Developers 1 to 17) 5% by mass of [Toners 1 to 17] and 95% by mass of the coated ferrite carrier were uniformly mixed for 5 minutes at 48 rpm using a Turbula mixer (manufactured by Willy & Bachofen (WAB)) to prepare toner developers 1 to 17. However, the toner developer 15 did not contain any inorganic external additives, and the toner 15 was used as the toner developer 15.

[0181] (evaluation) The toner developer thus obtained was evaluated for low-temperature fixability, heat-resistant storage stability, charge stability, and the presence or absence of abnormal images by the following evaluation methods.

[0182] <Evaluation of low-temperature fixability> The toner developer was placed in a Ricoh MPC 6003 copier, and an image was output. 2 A solid image was output onto paper (Ricoh Type 6200) through exposure, development, and transfer processes. The fixing linear speed was 256 mm / sec. The fixing temperature was changed in 5°C increments to measure the lowest temperature at which cold offset did not occur (lower fixing temperature: low-temperature fixability). The nip width of the fixing device was 11 mm. The evaluation criteria are as follows, with ⊚ and ◯ being judged to be sufficient results for practical use.

[0183] [Evaluation criteria for low-temperature fixability] ◎: Less than 120℃ 〇: 120℃ or higher but lower than 130℃ ×: 130℃ or higher

[0184] <Evaluation of heat-resistant storage stability> The toner was stored at 50° C. for 24 hours, and the penetration was measured in accordance with JIS K2235 (25° C.) using a penetrometer VR-5610 (Shimadzu Corporation) as the penetration measuring device. The evaluation criteria are as follows, with ⊚ and ◯ being judged to be sufficient results for practical use.

[0185] -Evaluation criteria for heat resistance and storage stability- ◎:25mm or more 〇: 20mm or more and less than 25mm ×: Less than 20mm

[0186] <Evaluation of long-term charging stability> Using a Ricoh copier, imajioMF-6550, which has low-temperature fixing properties, 200,000 copies of a test chart with an image area of ​​6% were made, and the degree of decrease in the amount of charge of the developer was evaluated. The evaluation criteria are as follows, with ⊚ and ◯ being judged to be sufficient results for practical use.

[0187] [Evaluation criteria for long-term charging stability] ◎: Very little decrease in charge amount and excellent durability ○: Less decrease in charge amount and better durability than conventional toner ×: Low durability equivalent to or lower than conventional toner

[0188] <Evaluation of Abnormal Images> Using a Ricoh copier, imajioMF-6550, with low-temperature fixing, in a high-temperature, high-humidity environment (27°C, 80%), 200,000 copies of a test chart with an image area of ​​6% were made using Askul Super White+ paper, and the presence or absence of abnormal images with black streaks was evaluated. The evaluation criteria are as follows, with ⊚ and ◯ being judged to be sufficient results for practical use.

[0189] [Evaluation criteria for the presence or absence of abnormal images] ◎: Abnormal image occurrence rate is less than 10% ○: Abnormal image occurrence rate is 10% or more but less than 20% ×: Abnormal image occurrence rate is 20% or more

[0190] The evaluation results are shown in Table 5.

[0191] [Table 5]

[0192] For example, aspects of the present invention are as follows. <1> A toner comprising base particles containing an amorphous polyester resin and a wax, and an external additive, the external additive contains silica whose surface is coated with a hydroxide of a metal element, The volume resistivity of the silica whose surface is coated with the hydroxide of the metal element is 2.0 × 10 10 Ω cm or more 1.0×10 11 A toner characterized by a specific resistance of Ω·cm or less. <2> The volume resistivity of the silica whose surface is coated with the hydroxide of the metal element is 3.0 × 10 10 Ω cm or more 7.0×10 10 characterized by a resistance of Ω·cm or less <1> The toner according to claim 1. <3> The toner has an average circularity of 0.930 to 0.960. <1> or <2> The toner according to claim 1. <4> The silica whose surface is coated with the hydroxide of a metal element is characterized in that the outermost surface is coated with an alkylsilane. <1> from <3> 1. The toner according to any one of claims 1 to 9. <5> The metal element is selected from aluminum, zinc, and magnesium. <1> from <4> 1. The toner according to any one of claims 1 to 9. <6> The silica whose surface is coated with the hydroxide of the metal element has a number average particle size of 10 nm or more and 30 nm or less. <1> from <5> 1. The toner according to any one of claims 1 to 9. <7> The base particles contain a crystalline polyester resin. <1> from <6> 1. The toner according to any one of claims 1 to 9. <8> The base particles are characterized in that they contain an aromatic petroleum resin. <1> from <7> 1. The toner according to any one of claims 1 to 9. <9> The wax contains a hydrocarbon wax. <1> from <8> 1. The toner according to any one of claims 1 to 9. <10> <1> from <9> 10. A toner storage unit containing the toner according to any one of the above items. <11> an electrostatic latent image carrier; an electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier; a developing means for developing the electrostatic latent image formed on the electrostatic latent image carrier with toner to form a toner image; a transfer means for transferring the toner image formed on the electrostatic latent image carrier onto a recording medium; a fixing unit for fixing the toner image transferred onto the recording medium, The toner <1> from <9> 2. An image forming apparatus comprising the toner according to any one of claims 1 to 11. <12> an electrostatic latent image forming step of forming an electrostatic latent image on an electrostatic latent image carrier; a developing step of developing the electrostatic latent image formed on the electrostatic latent image carrier with toner to form a toner image; a transfer step of transferring the toner image formed on the electrostatic latent image carrier onto a recording medium; a fixing step of fixing the toner image transferred onto the recording medium, The toner <1> from <9> 10. An image forming method, comprising the toner according to any one of claims 1 to 9. <13> <11> A method for producing a printed matter using the image forming apparatus according to claim 1, The toner <1> from <9> 10. A method for producing a printed matter, comprising the step of using the toner according to any one of claims 1 to 9 [Explanation of symbols]

[0193] 10 Electrostatic latent image carrier (photosensitive drum) 14~16, 23, 51 Laura 17 Cleaning device 18 Image forming means 20 Charging roller 21 Exposure equipment 22 Secondary transfer device 24 Secondary transfer belt 25 Fixing device 26 Fixing belt 27 Pressure roller 28 Sheet inverting device 32 Contact Glass 33 First running body 34 Second running body 35 Imaging lens 36 Reading sensor 40 Developing device 41 Developing belt 42 Developer storage section 43 Developer supply roller 44 Developing roller 45 Development unit 49 Registration roller 50 Intermediate transfer belt 52 Separation roller 53 Manual feed path 54 Manual feed tray 55 Switching claw 56 Discharge roller 57 Output tray 58 Corona charging device 60 Cleaning Device 61 Developing device 62 Transfer roller 63 Photoconductor cleaning device 64 Static elimination lamp 70 Static elimination lamp 80 Transfer roller 90 Cleaning Device 95 Transfer paper 100A, 100B, 100C image forming device 120 Image forming unit 130 manuscript table 142 Paper feed roller 143 Paper Bank 144 Paper cassette 145 Separation roller 146 Paper feed path 147 Conveyor roller 148 Paper feed path 150 Copying device body 200 Paper feed table 300 scanner 400 Automatic Document Feeder (ADF) [Prior art documents] [Patent documents]

[0194] [Patent Document 1] Japanese Patent Publication No. 2022-146467 [Patent Document 2] Patent Publication No. 2021-128245

Claims

1. A toner comprising base particles containing an amorphous polyester resin and a wax, and an external additive, the external additive contains silica whose surface is coated with a hydroxide of a metal element, The volume resistivity of the silica whose surface is coated with the hydroxide of the metal element is 2.0 × 10 １０ Ω・cm or more 1.0×10 １１ A toner characterized by having a viscosity of Ω·cm or less.

2. The volume resistivity of the silica whose surface is coated with the hydroxide of the metal element is 3.0 × 10 １０ Ω・cm or more 7.0×10 １０ 2. The toner according to claim 1, wherein the toner has a viscosity of Ω·cm or less.

3. 2. The toner according to claim 1, wherein the toner has an average circularity of 0.930 to 0.

960.

4. 2. The toner according to claim 1, wherein the silica having a surface coated with a hydroxide of a metal element has an outermost surface coated with an alkylsilane.

5. 2. The toner according to claim 1, wherein the metal element is selected from the group consisting of aluminum, zinc, and magnesium.

6. 2. The toner according to claim 1, wherein the silica whose surface is coated with the hydroxide of the metal element has a number average particle size of 10 nm or more and 30 nm or less.

7. 2. The toner according to claim 1, wherein the base particles contain a crystalline polyester resin.

8. 2. The toner according to claim 1, wherein the base particles contain an aromatic petroleum resin.

9. 2. The toner according to claim 1, wherein the wax comprises a hydrocarbon wax.

10. A toner storage unit containing the toner according to any one of claims 1 to 9.

11. an electrostatic latent image carrier; an electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier; a developing means for developing the electrostatic latent image formed on the electrostatic latent image carrier with toner to form a toner image; a transfer means for transferring the toner image formed on the electrostatic latent image carrier onto a recording medium; a fixing unit for fixing the toner image transferred onto the recording medium, An image forming apparatus, wherein the toner is the toner according to any one of claims 1 to 9.

12. an electrostatic latent image forming step of forming an electrostatic latent image on an electrostatic latent image carrier; a developing step of developing the electrostatic latent image formed on the electrostatic latent image carrier with toner to form a toner image; a transfer step of transferring the toner image formed on the electrostatic latent image carrier onto a recording medium; a fixing step of fixing the toner image transferred onto the recording medium, An image forming method, wherein the toner is the toner according to any one of claims 1 to 9.

13. A method for producing a printed matter by the image forming apparatus according to claim 11, A method for producing a printed matter, wherein the toner is the toner according to any one of claims 1 to 9.

Images