Toner, process cartridge, and image forming apparatus

Abstract

We provide toner that offers both durability in high-temperature environments and a wide fixing temperature range. [Solution] A toner having toner particles containing a binder resin, an olefin unit-containing polystyrene resin B, and an ester wax A, wherein the olefin unit-containing polystyrene resin B is a copolymer having an olefin unit and a styrene unit, and the ester wax A is an ester compound having the following structure, TIFF2026123784000011.tif3076 (In the formula, R independently represents an n-alkyl group.) The ester compound is characterized in that it has an n-hexicosyl group, an n-nonadecyl group, and an n-heptadecyl group as n-alkyl groups, and based on the total mass of the n-alkyl groups, the content of the n-hexicosyl group is 50.0% by mass or more and 80.0% by mass or less, the content of the n-nonadecyl group is 5.0% by mass or more and 15.0% by mass or less, and the content of the n-heptadecyl group is 15.0% by mass or more and 30.0% by mass or less.

Description

[Technical Field]

[0001] The present invention relates to toner used in recording methods utilizing electrophotography, electrostatic recording, and toner jet recording, and further to a process cartridge and image forming apparatus using said toner. [Background technology]

[0002] In recent years, electrophotographic forming machines have been required to achieve higher printing speeds, improved environmental adaptability for printing in various environments, and smaller cartridges. To make these possible, further improvements to toner are also needed. For example, to contribute to the increased speed of electrophotographic machines, improved toner fixation is required. If low-temperature fixation is improved, the process speed of fixing toner to paper can be increased, leading to higher speeds. Also, if the temperature range in which toner can be fixed can be expanded, stable image output can be achieved even when printing at high speeds. Thus, expanding the temperature range in which toner can be fixed and improving low-temperature fixation are important challenges for electrophotographic forming machines. Patent Document 1 discloses a toner that has excellent low-temperature fixing properties and suppresses toner ejection after being left at high temperatures by adding a block copolymer containing a conjugated diene structure. Furthermore, as one means of expanding the fixable temperature range, it is known that using multiple types of waxes with different melting points in combination is an effective way to ensure release properties over a wide fixable temperature range. Patent Document 2 discloses a toner that can improve low-temperature fixability and heat-resistant storage properties by using an ester wax produced by the esterification reaction of pentaerythritol with multiple types of monocarboxylic acids. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Special WO2023 / 127815 [Patent Document 2] Special WO2020 / 075660 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] However, it was found that the toner described in Patent Document 1 has a narrow fixing temperature range because the wax consists of only one component, which presents challenges in image output on high-speed machines. Furthermore, while the toner described in Patent Document 2 has improved low-temperature fixation properties, it was found to have issues with durability in high-temperature environments. Therefore, there is a need for further materials, means, and improvement methods to achieve both durability and adhesion in high-temperature environments. This disclosure provides a toner that achieves both durability and a wide fixing temperature range, even in high-temperature environments. [Means for solving the problem]

[0005] The present invention relates to a toner having toner particles containing a binder resin, an olefin unit-containing polystyrene resin B, and an ester wax A. The olefin unit-containing polystyrene resin B is a copolymer having an olefin unit and a styrene unit. The ester wax A is an ester compound having the following structure,

[0006] [ka] (In the formula, R independently represents an n-alkyl group.) The ester compound has an n-henicosyl group, an n-nonadecyl group, and an n-heptadecyl group as the n-alkyl group. This invention relates to a toner characterized in that, based on the total mass of the n-alkyl groups, the content of n-henicosyl groups is 50.0% by mass or more and 80.0% by mass or less, the content of n-nonadecyl groups is 5.0% by mass or more and 15.0% by mass or less, and the content of n-heptadecyl groups is 15.0% by mass or more and 30.0% by mass or less. Furthermore, the present invention relates to a process cartridge detachable from an image forming apparatus, wherein the process cartridge includes toner, a toner container for containing the tonner, and has the tonner being the tonner having the above-described configuration, and relates to a process cartridge. Furthermore, the present invention relates to an image forming apparatus including toner, a toner carrier for carrying the tonner, an electrostatic latent image carrier, charging means for charging the surface of the electrostatic latent image carrier with a charging member, electrostatic latent image forming means for forming an electrostatic latent image on the charged electrostatic latent image carrier, developing means for developing the electrostatic latent image using the tonner to form a toner image on the electrostatic latent image carrier, transfer means for transferring the toner image to a recording medium, and fixing means for fixing the toner image transferred onto the recording medium to the recording medium, the tonner being the tonner having the above-described configuration, and relates to an image forming apparatus.

Advantages of the Invention

[0007] According to the present invention, it is possible to provide a tonner that achieves both durability and a wide fixing temperature range even in a high-temperature environment.

Brief Description of the Drawings

[0008] [Figure 1] FIG. 1 is a schematic diagram of an image forming apparatus.

Embodiments for Carrying Out the Invention

[0009] The present invention will be described in more detail below with reference to embodiments, but is not limited to these embodiments. Unless otherwise specified, the notations "XX or greater and YY or less" or "XX~YY" that represent a numerical range mean a numerical range that includes the lower and upper limits, which are the endpoints.

[0010] [Features of the present invention] The toner of the present invention is a toner having toner particles containing a binder resin, an olefin unit-containing polystyrene resin B, and an ester wax A, The olefin unit-containing polystyrene resin B is a copolymer having an olefin unit and a styrene unit. The ester wax A is an ester compound having the following structure,

[0011] [ka] (In the formula, R independently represents an n-alkyl group.)

[0012] The ester compound has an n-henicosyl group, an n-nonadecyl group, and an n-heptadecyl group as the n-alkyl group. This product is characterized in that, based on the total mass of the n-alkyl groups, the content of n-henicosyl groups is 50.0% by mass or more and 80.0% by mass or less, the content of n-nonadecyl groups is 5.0% by mass or more and 15.0% by mass or less, and the content of n-heptadecyl groups is 15.0% by mass or more and 30.0% by mass or less.

[0013] The factors that enabled the toner of this invention to achieve both durability and a wide fixing temperature range even in high-temperature environments are not clear, but the inventors speculate as follows.

[0014] Toners containing ester waxes, which are produced from multiple types of monocarboxylic acids, can be fixed over a wide temperature range, as described above. Generally, when different components are mixed, the lattice energy of the crystal structure of each component weakens, making them easier to melt; this phenomenon is called melting point depression. Even when multiple types of waxes are mixed, the melting point is lowered due to the effect of melting point depression, causing them to melt more easily in high-temperature environments. As a result, some of the wax melts in high-temperature environments, causing the toner to soften locally. Therefore, when printing in high-speed modes in high-temperature environments, the softened parts of the toner become more prone to deformation when rubbed against other components such as the developing roller, increasing their adhesion to the developing material, which is thought to lead to image defects such as developing streaks.

[0015] The olefin unit-containing polystyrene resin used in this invention has a high structural affinity with ester wax and possesses olefin moieties that exhibit high resilience against external stimuli. Therefore, the olefin unit-containing polystyrene resin can be located near the ester wax, and its resilience allows it to exert stress against deformation caused by the melting of the wax. Furthermore, the aromatic rings contained in the styrene units cause π-π stacking, leading to the accumulation of olefin unit-containing polystyrene resins and the formation of pseudo-crosslinks. As a result, the resilience is further enhanced, allowing for more effective suppression of deformation. Consequently, toner deformation can be suppressed and recovery from deformation can be achieved, contributing to the suppression of image defects such as development streaks.

[0016] [Constituent materials and physical properties of the toner of the present invention] Next, the materials that can be used in the toner of the present invention will be described in detail below.

[0017] <Ester Wax A> The ester wax A of the present invention is an ester compound having the following structure.

[0018] [ka] (In the formula, each R independently represents an n-alkyl group.)

[0019] The ester wax A contains n-henicosyl, n-nonadecyl, and n-heptadecyl groups as n-alkyl groups. Of these three alkyl groups, the n-henicosyl group is present in the largest quantity, the n-heptadecyl group is included to cover a lower temperature fixing range, and the n-nonadecyl group is included to ensure stable fixing even in the intermediate temperature range, especially in the low temperature range. The inclusion of these three alkyl groups allows for stable fixing over a wide temperature range.

[0020] The content of n-alkyl groups in the ester compound must be limited to 50.0% to 80.0% by mass for n-henicosyl groups, 5.0% to 15.0% by mass for n-nonadecyl groups, and 15.0% to 30.0% by mass for n-heptadecyl groups. Preferably, the content of n-henicosyl groups is 60.0% to 70.0% by mass, the content of n-nonadecyl groups is 7.5% to 15.0% by mass, and the content of n-heptadecyl groups is 20.0% to 30.0% by mass.

[0021] Furthermore, it is preferable that the n-alkyl group in the ester compound further contains an n-pentadecyl group. The inclusion of the n-pentadecyl group improves the suppression of image mottling. Mottle is an image defect in which density unevenness occurs due to variations in how heat is applied to the toner caused by irregularities on the surface of the paper. One of the causes of these image defects is that toner placed in the depressions of the paper is not uniformly pressurized by fixing members such as fixing rollers, i.e., it melts under uneven pressure, so the wax does not melt completely, and the way the toner melts and spreads changes. Because the n-pentadecyl group has a low molecular weight, it has a low melting point and dissolves easily, and because it has low viscosity, it spreads easily on the toner surface, thus promoting uniform toner dissolution when pressurized by the fixing roller. In addition, the effect of the olefin unit restores the deformation of the toner, suppressing irregularities in shape, making uneven pressure less likely to occur, and leading to improved mottling suppression. The combination of these two effects improves mottling suppression.

[0022] To fully exhibit the effects of the present invention, the content of n-pentadecyl groups is preferably 0.1% by mass or more and 5.0% by mass or less, based on the total mass of the n-alkyl groups.

[0023] Ester wax A can be manufactured according to conventional methods. One method for producing such ester wax is to prepare it by condensing pentaerythritol with various carboxylic acids such as behenic acid, arachidic acid, stearic acid, and palmitic acid. Of the n-alkyl groups mentioned above, the n-henicosyl group is derived from behenic acid, the n-nonadecyl group from arachidic acid, the n-heptadecyl group from stearic acid, and the n-pentadecyl group from palmitic acid. Furthermore, the n-henicosyl group is an n-alkyl group with 21 carbon atoms, the n-nonadecyl group is an n-alkyl group with 19 carbon atoms, the n-heptadecyl group is an n-alkyl group with 17 carbon atoms, and the n-pentadecyl group is an n-alkyl group with 15 carbon atoms.

[0024] <Other waxes> In addition to the ester wax A described above, other waxes may be added to the toner of the present invention for purposes such as imparting release properties.

[0025] Other waxes include paraffin wax, microcrystalline wax, petroleum-based hydrocarbon waxes such as petrolatum and their derivatives, montan wax and its derivatives, and hydrocarbon waxes and their derivatives produced by the Fischer-Tropsch process. Monofunctional ester waxes, such as esters of monohydric alcohols and aliphatic carboxylic acids, or esters of monohydric carboxylic acids and aliphatic alcohols, including behenyl behenate, stearyl stearate, and palmityl palmitate; Difunctional ester waxes, such as esters of dihydric alcohols and aliphatic carboxylic acids, or esters of dihydric carboxylic acids and aliphatic alcohols, including ethylene glycol and propylene glycol; Trifunctional ester waxes, such as esters of trivalent alcohols and aliphatic carboxylic acids, or esters of trivalent carboxylic acids and aliphatic alcohols, like glycerol tribehenate; Hexafunctional ester waxes, such as esters of hexavalent alcohols and aliphatic carboxylic acids, or esters of hexavalent carboxylic acids and aliphatic alcohols, including dipentaerythritol hexastearate and dipentaerythritol hexapalmitate; Esters of polyhydric alcohols and aliphatic carboxylic acids, such as polyglycerol behenates, or esters of polyhydric carboxylic acids and aliphatic alcohols; Natural ester waxes such as carnauba wax and rice wax; Ester waxes, such as those mentioned above. Examples include polyolefin hydrocarbon waxes such as polyethylene and polypropylene and their derivatives, and natural waxes such as carnauba wax and candelilla wax and their derivatives. Derivatives also include oxides, block copolymers with vinyl monomers, and graft-modified products.

[0026] Other examples include alcohols such as higher aliphatic alcohols; fatty acids such as stearic acid and palmitic acid, or their acid amides, esters, and ketones; hydrogenated castor oil and its derivatives; plant waxes; and animal waxes. These can be used alone or in combination.

[0027] <Olefin unit-containing polystyrene resin B> The olefin unit-containing polystyrene resin B of the present invention is a copolymer containing an olefin unit containing an olefin unit C and a styrene unit.

[0028] The copolymer is more preferably a block copolymer because it has superior stacking properties and resilience. The number of polymer blocks and their bonding configuration are not particularly limited, as long as the block copolymer contains one or more polyolefin segments and polystyrene segments containing olefin units C. Specific examples of block copolymers are as follows. In the following examples, S represents a polystyrene segment, O represents a polyolefin segment containing olefin units C, and n represents an integer of 2 or more. (a) Styrene-olefin copolymer represented as SO (b) Styrene-olefin-styrene copolymer represented as SOS (c) Olefin-styrene-olefin copolymer represented as OSO (d) Styrene-olefin-styrene-olefin block copolymers represented as SOSO (e) A mixture of block copolymers obtained by arbitrarily combining two or more of the above (a) to (d). However, the block copolymer is not limited to (a) to (e) above. Preferred block copolymers in this disclosure include (a), (b), and (e), which are mixtures of block copolymers obtained by combining (a) and (b).

[0029] The olefin unit C contained in the polyolefin segment of the present invention has the structure of the following structural formulas (1), (2), (3), or (4). The following structural formulas are characterized by having branching in the structure. This reduces the cohesiveness between the olefin units C, which promotes π-π stacking of the aromatic rings of the styrene units, resulting in an improved restorative force.

[0030] [ka]

[0031] In particular, the structures of structural formula (1) or structural formula (2) are preferred because the cohesiveness between units is further reduced, and the structure of structural formula (1) is more preferred because it has superior affinity with ester wax A.

[0032] In addition to the olefin unit C described above, the polyolefin segment may also contain other olefin units. Specifically, examples include olefin-derived olefin units such as ethylene, propylene, butene, and butadiene. Within the polyolefin segment, the bonding form between the olefin unit C and the other olefin units is not particularly limited; they may form blocks or be randomly bonded. The polyolefin segment is substantially composed of olefin unit C and other olefin units. Specifically, 90% or more by mass consists of olefin unit C and other olefin units. More preferably, 98% or more by mass consists of olefin unit C and other olefin units, and even more preferably, it consists only of olefin unit C and other olefin units.

[0033] The polystyrene segment consists substantially only of styrene units. Specifically, 98% or more by mass is styrene units. It is more preferable that it consists only of styrene units. Other units that can be used include styrene derivative units derived from styrene derivatives such as vinyltoluene and α-methylstyrene; unsaturated fatty acid units derived from unsaturated fatty acids such as acrylic acid and methacrylic acid; acrylic ester units derived from acrylic acid esters such as methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, and dimethylaminoethyl acrylate; and methacrylic ester units derived from methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, and dimethylaminoethyl methacrylate.

[0034] Polystyrene resin B containing olefin units can be manufactured according to conventional methods. One example of a method for manufacturing such polystyrene resin B containing olefin units is to sequentially polymerize styrene and olefin by anionic living polymerization to form polymer blocks, and then, if necessary, react with a coupling agent to perform coupling. The total content of olefin units and styrene units in polystyrene resin B containing olefin units is preferably 91% by mass or more, and more preferably 95% by mass or more, based on the total mass of polystyrene resin B containing olefin units.

[0035] In this invention, commercially available block copolymers can also be used. Examples of commercially available block copolymers include the trade names "Septon" and "Hybler" (manufactured by Kuraray Co., Ltd.), "Quintac" (manufactured by Nippon Zeon Co., Ltd.), "JSR-SIS" (manufactured by JSR Corporation), "Vector" (manufactured by DEXCO Polymers), "Asaprene," "Toughprene," and "Toughtec" (manufactured by Asahi Kasei Chemicals Corporation), and as a commercially available random copolymer, "STYRENE / ISOPRENE COPOLYMER" (trade name, manufactured by Aldrich Corporation) can be used.

[0036] <Binding resin> The binder resin of the present invention is preferably a styrene-acrylic copolymer. Being a styrene-acrylic copolymer allows the olefin unit-containing polystyrene resin B to be compatible with the styrene portion, resulting in the suppression of image artifacts.

[0037] As the styrene-acrylic copolymer, any conventionally known styrene-acrylic copolymer can be used without particular limitations, as long as it is a copolymer of a monomer composition containing styrene and at least one acrylic monomer selected from acrylic acid and its derivatives, and methacrylic acid and its derivatives. In particular, the styrene unit content is preferably 60% to 90% by mass, and more preferably 70% to 80% by mass, relative to the entire styrene-acrylic copolymer. Furthermore, the acrylic unit content is preferably 10% to 40% by mass, and more preferably 20% to 30% by mass.

[0038] Examples of acrylic monomers include acrylic acid esters such as methyl acrylate and n-butyl acrylate (n-butyl acrylate); methacrylic acid esters such as methyl methacrylate, 2-hydroxyethyl methacrylate, t-butyl methacrylate, and 2-ethylhexyl methacrylate; acrylic acid, methacrylic acid, etc. Among these, it is preferable to use an acrylic acid ester or a methacrylic acid ester, more preferable to use n-butyl acrylate or methyl methacrylate, and even more preferable to use n-butyl acrylate.

[0039] In addition to the styrene and acrylic monomers mentioned above, the styrene-acrylic copolymer of the present invention can use conventionally known polymerizable monomers without any particular limitations. Specifically, examples include monofunctional monomers having one polymerizable unsaturated bond in the molecule, such as aromatic monomers like α-methylstyrene and vinyltoluene; unsaturated dicarboxylic acids like maleic acid; unsaturated dicarboxylic acid anhydrides like maleic anhydride; nitrile vinyl monomers like acrylonitrile; halogen-containing vinyl monomers like vinyl chloride; and nitro vinyl monomers like nitrostyrene; as well as polyfunctional monomers having multiple polymerizable unsaturated bonds in the molecule, such as divinylbenzene, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, and trimethylolpropanetri(meth)acrylate.

[0040] Furthermore, using macromonomers as part of the polymerizable monomer allows for a good balance between the storage properties and low-temperature fixability of the resulting toner. Macromonomers are oligomers or polymers with polymerizable carbon-carbon unsaturated double bonds at the ends of their molecular chains, and a number-average molecular weight of typically 1,000 to 30,000, indicating high reactivity. It is preferable that the macromonomer yields a polymer with a glass transition temperature (Tg) higher than that of the polymer obtained by polymerizing monovinyl monomers. The macromonomer is used in amounts of preferably 0.03 to 5 parts by mass, and more preferably 0.05 to 1 part by mass, per 100 parts by mass of monovinyl monomer.

[0041] Furthermore, in addition to the styrene-acrylic copolymer described above, conventionally known binder resins can be used as the binder resin of the present invention without any particular limitations. Specifically, examples include polyester resins, vinyl resins, polyurethane resins, and polyamide resins.

[0042] <Coloring agent> The toner of the present invention may contain a colorant. The colorant can be any conventionally known black, yellow, magenta, and cyan pigments and dyes, magnetic materials, etc., without any particular limitations.

[0043] Examples of black colorants include black pigments such as carbon black.

[0044] Examples of yellow colorants include yellow pigments and dyes such as monoazo compounds, disazo compounds, condensed azo compounds, isoindolinone compounds, benzimidazolon compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds.

[0045] Specifically, examples include CI Pigment Yellow 74, 93, 95, 109, 111, 128, 155, 174, 180, 185, and CI Solvent Yellow 162.

[0046] Examples of magenta colorants include magenta pigments and dyes such as monoazo compounds, condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolon compounds, thioindigo compounds, and perylene compounds.

[0047] Specifically, examples include CI Pigment Red 2, 3, 5, 6, 7, 23, 48:2, 48:3, 48:4, 57:1, 81:1, 122, 144, 146, 150, 166, 169, 177, 184, 185, 202, 206, 220, 221, 238, 254, 269, and CI Pigment Violet 19.

[0048] Examples of cyanide colorants include copper phthalocyanine compounds and their derivatives, anthraquinone compounds, and cyanide pigments and dyes such as basic dye lake compounds.

[0049] Specifically, examples include CI Pigment Blue 1, 7, 15, 15:1, 15:2, 15:3, 15:4, 60, 62, and 66.

[0050] The coloring agent content is preferably 1.0 part by mass or more and 20.0 parts by mass or less per 100.0 parts by mass of the binder resin.

[0051] Furthermore, toner can be made magnetic by incorporating a magnetic material. In this case, the magnetic material can also serve as a colorant.

[0052] Examples of magnetic materials include iron oxides such as magnetite, hematite, and ferrite; metals such as iron, cobalt, and nickel; and alloys and mixtures thereof of these metals with metals such as aluminum, cobalt, copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, and vanadium.

[0053] When a magnetic material is used as a coloring agent, the content of the magnetic material is preferably 20.0 parts by mass or more and 120.0 parts by mass or less per 100.0 parts by mass of the binder resin.

[0054] <Static control agent> Other additives that can be used to improve the chargeability of the toner include positively or negatively charged charge control agents.

[0055] The charge control agent is not particularly limited as long as it is one that is generally used as a charge control agent for toner. However, among charge control agents, positively charged or negatively charged charge control resins are preferred because they can impart stable charge properties (charge stability) to toner particles.

[0056] Examples of positively charged charge control agents include nigrosine dyes, quaternary ammonium salts, triaminotriphenylmethane compounds, and imidazole compounds, as well as polyamine resins as preferred charge control resins, and quaternary ammonium group-containing copolymers and quaternary ammonium base-containing copolymers. Among these, the use of quaternary ammonium group-containing copolymers or quaternary ammonium base-containing copolymers is more preferred.

[0057] Examples of negatively charged charge control agents include azo dyes containing metals such as Cr, Co, Al, and Fe, metal salicylate compounds and alkylsalicylate compounds, and preferably used charge control resins such as sulfonic acid group-containing copolymers, sulfonic acid base-containing copolymers, carboxylic acid group-containing copolymers and carboxylic acid base-containing copolymers.

[0058] The weight-average molecular weight (Mw) of the charge-controlled resin is measured by gel permeation chromatography (GPC) using tetrahydrofuran and is in the range of 5,000 to 30,000 in polystyrene equivalent, preferably in the range of 8,000 to 25,000, and more preferably in the range of 10,000 to 20,000.

[0059] Furthermore, the copolymerization ratio of monomers having functional groups such as quaternary ammonium groups and sulfonic acid bases in the electrostatically controlled resin is in the range of 0.5% by mass or more and 12% by mass or less, preferably in the range of 1.0% by mass or more and 6% by mass or less, and more preferably in the range of 1.5% by mass or more and 3% by mass or less.

[0060] In the present invention, it is desirable to use the charge control agent in a ratio of 0.01 parts by mass to 10 parts by mass, preferably 0.03 parts by mass to 8 parts by mass, per 100 parts by mass of the binder resin. When the amount of charge control agent added is 0.01 to 10 parts by mass, the risk of fogging and the risk of printing smudging are both small.

[0061] <External Additives> The toner of the present invention may contain external additives. There are no particular limitations on the external additives, and conventionally known external additives can be used. Examples of external additives include raw silica fine particles such as wet-processed silica and dry-processed silica, or surface-treated silica fine particles obtained by surface-treating these raw silica fine particles with a treatment agent such as a silane coupling agent, a titanium coupling agent, or a silicone oil; metal oxide fine particles such as titanium oxide fine particles, aluminum oxide fine particles, and zinc oxide fine particles, or metal oxide fine particles obtained by hydrophobizing metal oxides; fatty acid metal salts such as zinc stearate and calcium stearate; metal complexes of aromatic carboxylic acids such as salicylic acid, alkyl salicylic acid, dialkyl salicylic acid, naphthoic acid, and dicarboxylic acid; clay minerals such as hydrotalcite; and fluorine-based resin fine particles such as vinylidene fluoride fine particles and polytetrafluoroethylene fine particles.

[0062] The content of external additives is preferably 0.1 parts by mass or more and 5.0 parts by mass or less per 100.0 parts by mass of toner particles.

[0063] <Average circularity> The toner of the present invention preferably has an average circularity (specific measurement method will be described later) of 0.960 or more and 0.995 or less. Maintaining the circularity within this range, where deformation is minimal, helps to suppress image defects such as development streaks.

[0064] [Method for obtaining toner according to the present invention] Next, the method for obtaining the toner of the present invention will be described in detail below.

[0065] <Method for manufacturing toner particles> The method for producing toner particles of the present invention is not particularly limited, and methods such as suspension polymerization, dissolution-suspension, emulsification-coagulation, and pulverization can be used. Among these, suspension polymerization is preferred.

[0066] The following describes in detail the method for obtaining toner using suspension polymerization.

[0067] (Process 1: Granulation process) A polymerizable monomer composition containing a polymerizable monomer, a colorant, an olefin unit-containing polystyrene resin B, and an ester wax A is dispersed in an aqueous medium containing a dispersion stabilizer, a polymerization initiator is added, and then droplet formation of the polymerizable monomer composition is performed. The method of droplet formation is not particularly limited, but for example, it is performed using a device capable of strong stirring, such as an (in-line type) emulsifier / disperser (manufactured by Taiheiyo Kiko Co., Ltd., product name: Milder) or a high-speed emulsifier / disperser (manufactured by Primix Corporation, product name: TK Homomixer MARK II).

[0068] Examples of polymerization initiators include potassium persulfate and persulfates such as ammonium persulfate; azo compounds such as 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(2-methyl-N-(2-hydroxyethyl)propionamide), 2,2'-azobis(2-amidinopropane)dihydrochloride, 2,2'-azobis(2,4-dimethylvaleronitrile), and 2,2'-azobisisobutyronitrile; and organic peroxides such as di-t-butyl peroxide, benzoyl peroxide, t-butyl peroxy-2-ethylhexanoate, t-hexyl peroxy-2-ethylbutanoate, diisopropyl peroxydicarbonate, di-t-butyl peroxyisophthalate, and t-butyl peroxyisobutyrate. These can be used individually or in combination of two or more. Among these options, organic peroxides are preferred because they reduce the amount of residual polymerizable monomers and offer excellent print durability.

[0069] Among organic peroxides, peroxyesters are preferred because they have good initiator efficiency and can reduce the amount of residual polymerizable monomers, and non-aromatic peroxyesters, i.e., peroxyesters without aromatic rings, are more preferred.

[0070] The polymerization initiator may be added after the polymerizable monomer composition has been dispersed in an aqueous medium but before droplet formation, as described above, or it may be added to the polymerizable monomer composition before it is dispersed in the aqueous medium.

[0071] The amount of polymerization initiator added to the polymerization of the polymerizable monomer composition is preferably 0.1 parts by mass or more and 20 parts by mass or less, more preferably 0.3 parts by mass or more and 15 parts by mass or less, and particularly preferably 1 part by mass or more and 10 parts by mass or less, per 100 parts by mass of monomer.

[0072] In this invention, an aqueous medium refers to a medium whose main component is water.

[0073] In the present invention, it is preferable to include a dispersion stabilizer in the aqueous medium. Examples of dispersion stabilizers include inorganic compounds such as sulfates such as barium sulfate and calcium sulfate; carbonates such as barium carbonate, calcium carbonate, and magnesium carbonate; phosphates such as calcium phosphate; metal oxides such as aluminum oxide and titanium oxide; metal hydroxides such as aluminum hydroxide, magnesium hydroxide, and ferric hydroxide; and organic compounds such as water-soluble polymers such as polyvinyl alcohol, methylcellulose, and gelatin; anionic surfactants; nonionic surfactants; and amphoteric surfactants.

[0074] The above-mentioned dispersion stabilizers can be used individually or in combination of two or more. The amount of dispersion stabilizer added is preferably 0.1 parts by mass or more and 20 parts by mass or less, and more preferably 0.2 parts by mass or more and 10 parts by mass or less, per 100 parts by mass of polymerizable monomer.

[0075] Among the above-mentioned dispersion stabilizers, inorganic compounds, particularly colloids of poorly water-soluble metal hydroxides, are preferred. By using inorganic compounds, especially colloids of poorly water-soluble metal hydroxides, the particle size distribution of toner particles can be narrowed, and the amount of residual dispersion stabilizer after washing can be reduced. As a result, the resulting toner can reproduce images clearly and does not worsen environmental stability.

[0076] (Step 2: Polymerization step) As in step 1, droplet formation is performed, the resulting aqueous dispersion medium is heated to initiate polymerization, and an aqueous dispersion of resin particles containing a binder resin, a colorant, olefin unit-containing polystyrene resin B, and ester wax A is formed.

[0077] The polymerization temperature of the polymerizable monomer composition is preferably 50°C or higher, and more preferably 60 to 95°C. The polymerization reaction time is preferably 1 to 20 hours, and more preferably 2 to 15 hours.

[0078] In order to carry out polymerization while stably dispersing droplets of the polymerizable monomer composition, the polymerization reaction may proceed while carrying out dispersion treatment by stirring, following step 1 above.

[0079] The resin particles may be used as is or with the addition of external additives as toner, but it is preferable to use so-called core-shell type (or "capsule type") resin particles, which are obtained by using the resin particles as a core layer and creating a shell layer different from the core layer on the outside. Core-shell type resin particles allow for a balance between lowering the fixing temperature and preventing aggregation during storage by coating a core layer made of a material with a lower softening point with a material with a higher softening point.

[0080] There are no particular restrictions on the method for producing core-shell type toner particles using the resin particles described above, and they can be produced by conventionally known methods. In situ polymerization and phase separation methods are preferred from the viewpoint of production efficiency.

[0081] The following describes a method for producing core-shell type resin particles by in situ polymerization.

[0082] Core-shell type resin particles can be obtained by adding a polymerizable monomer (polymerizable monomer for shells) and a polymerization initiator to an aqueous medium in which toner particles are dispersed, and then polymerizing them.

[0083] For the shell polymerizable monomer, the same monomers as those described above can be used. Among these, monomers that yield polymers with a Tg exceeding 80°C, such as styrene, acrylonitrile, and methyl methacrylate, are preferred to be used individually or in combination of two or more.

[0084] Polymerization initiators used for polymerizing polymerizable monomers for shells include persulfate metal salts such as potassium persulfate and ammonium persulfate; azo-based initiators such as 2,2'-azobis(2-methyl-N-(2-hydroxyethyl)propionamide) and 2,2'-azobis-(2-methyl-N-(1,1-bis(hydroxymethyl)2-hydroxyethyl)propionamide); and other water-soluble polymerization initiators. These can be used individually or in combination of two or more. The amount of polymerization initiator is preferably 0.1 parts by mass to 30 parts by mass, more preferably 1 part by mass to 20 parts by mass, per 100 parts by mass of polymerizable monomers for shells.

[0085] The polymerization temperature of the shell layer is preferably 50°C or higher, and more preferably 60 to 95°C. The polymerization reaction time is preferably 1 to 20 hours, and more preferably 2 to 15 hours.

[0086] (Step 3: Volatile component removal step) A volatile component removal step may be performed to remove unreacted polymerizable monomers and other substances from the resin particle dispersion after the polymerization process is complete. The volatile component removal step is performed by heating and stirring the resin particle dispersion in a stirring tank equipped with a stirring means. The heating conditions during the volatile component removal step are adjusted as appropriate, taking into account the vapor pressure of the components to be removed, such as polymerizable monomers. The volatile component removal step can be performed under atmospheric pressure or reduced pressure.

[0087] (Post-processing: washing, filtration, dewatering, drying, and classification) Toner particles are obtained by performing washing, filtering, dehydration, drying, and classification processes on the aqueous dispersion of resin particles produced by the above process, according to standard methods.

[0088] In the above cleaning method, if an inorganic compound is used as the dispersion stabilizer, it is preferable to dissolve and remove the dispersion stabilizer in water by adding an acid or alkali to the aqueous dispersion of toner particles. If a colloid of poorly water-soluble inorganic hydroxide is used as the dispersion stabilizer, it is preferable to add an acid to adjust the pH of the aqueous dispersion of toner particles to 6.5 or below. As the acid to be added, inorganic acids such as sulfuric acid, hydrochloric acid, and nitric acid, as well as organic acids such as formic acid and acetic acid, can be used, but sulfuric acid is particularly preferred because of its high removal efficiency and low burden on manufacturing equipment.

[0089] The dehydration and filtration methods are not particularly limited and can be any of the known methods. For example, centrifugal filtration, vacuum filtration, and pressure filtration can be used. Similarly, the drying method is not particularly limited and can be any of the various methods used.

[0090] <Toner manufacturing method> When adding an external additive to toner particles to produce toner (toner product), there are no particular restrictions on the mixer used to add the external additive to the toner particles; any known mixer, whether dry or wet, can be used. Examples include the FM mixer (manufactured by Nippon Coke Industries Co., Ltd.), the Super Mixer (manufactured by Kawata Co., Ltd.), the Nobilta (manufactured by Hosokawa Micron Corporation), and the Hybridizer (manufactured by Nara Machinery Co., Ltd.). To control the coating state of the external additive, the rotation speed, processing time, and water temperature and volume of the jacket of the above-mentioned external additive device can be adjusted to prepare the toner.

[0091] Furthermore, sieving devices used to separate coarse particles after external addition include the Ultrasonic (manufactured by Koei Sangyo Co., Ltd.), Resona Sieve, Gyro Shifter (manufactured by Tokuju Kogyo Co., Ltd.), Vibrasonic System (manufactured by Dalton Co., Ltd.), Soniclean (manufactured by Shinto Kogyo Co., Ltd.), Turbo Screener (manufactured by Turbo Kogyo Co., Ltd.), and Micro Shifter (manufactured by Makino Sangyo Co., Ltd.).

[0092] [Method for measuring physical properties] The following describes the methods for measuring the physical properties of toner and each material.

[0093] <Measurement of glass transition temperature (Tg) of resin particles (toner particles)> The glass transition temperature (Tg) was measured using a differential calorimetry analyzer "Q1000" (TA Instruments) in accordance with ASTM D3418-82. The temperature correction for the instrument's detection unit was performed using the melting points of indium and zinc, and the heat correction was performed using the heat of fusion of indium. Specifically, approximately 3 mg of resin particles were accurately weighed and placed in an aluminum pan. An empty aluminum pan was used as a reference, and measurements were taken within the measurement range of 30 to 200°C at a heating rate of 10°C / min. During this heating process, a change in specific heat was obtained in the temperature range of 40°C to 100°C. The straight line extending from the baseline before the change in specific heat was defined as the first straight line, the straight line extending from the baseline after the change in specific heat was defined as the second straight line, and the straight line equidistant in the vertical direction from the first and second straight lines was defined as the third straight line. The temperature at the intersection of the third straight line and the stepped portion of the differential thermal curve (the so-called midpoint glass transition temperature) was defined as the glass transition temperature Tg of the resin particles.

[0094] <Identification of ester wax A in toner> (1) Method for separating wax from toner First, the melting point of the wax in the toner is measured using a thermal analyzer (DSC Q2000, manufactured by TA Instruments Japan Co., Ltd.). 3.0 mg of the toner sample is placed in an aluminum pan (KIT NO. 0219-0041) sample container, which is then placed on a holder unit and set in an electric furnace. Under a nitrogen atmosphere, the sample is heated from 30°C to 200°C at a heating rate of 10°C / min, and the DSC curve is measured using a differential scanning calorimeter (DSC) to calculate the melting point of the wax in the toner sample.

[0095] Next, the toner is dispersed in ethanol, which is a poor solvent for toner, and the temperature is raised to a level above the melting point of the wax. Pressure may be applied as needed during this process. Through this operation, the wax above its melting point is melted and extracted into the ethanol. If heating and pressurization are applied, the wax can be separated from the toner by solid-liquid separation while maintaining the pressurized state. The extracted liquid is then dried and solidified to obtain the wax.

[0096] (2) Identification of waxes by pyrolysis GC-MS The specific conditions for identifying waxes by pyrolysis GC-MS are shown below. Mass spectrometer: ThermoFisher Scientific ISQ GC system: ThermoFisher Scientific FocusGC Ion source temperature: 250℃ Ionization method: EI Mass range: 50-1000 m / z Column: HP-5MS [30m] Pyrolysis apparatus: JPS-700, manufactured by Nippon Analytical Industry Co., Ltd.

[0097] A small amount of wax separated by extraction and 1 μL of tetramethylammonium hydroxide (TMAH) are added to pyrofoil heated to 590°C. The prepared sample is subjected to thermal decomposition GC-MS analysis under the above conditions to obtain peaks derived from the wax. If the wax is an ester compound, peaks for the alcohol component and the carboxylic acid component are obtained separately. Due to the action of the methylating agent TMAH, the alcohol component and the carboxylic acid component are detected as methylated products. By analyzing the obtained peaks and identifying the structure of the wax, the molecular weight can also be obtained.

[0098] <Method for measuring melting point> The melting point of crystalline materials (wax) is measured using a differential scanning calorimeter (DSC) Q2000 (TA Instruments) under the following conditions. Heating rate: 10℃ / min Measurement start temperature: 20℃ Measurement end temperature: 180℃ The temperature correction for the device's detection unit uses the melting points of indium and zinc, while the heat of fusion of indium is used for heat quantity correction.

[0099] Specifically, 5 mg of the sample is accurately weighed, placed in an aluminum pan, and measured once. An empty aluminum pan is used as a reference. The peak temperature of the maximum endothermic peak at that time is defined as the melting point.

[0100] <Separation of olefin unit-containing polystyrene resin B> The chloroform-soluble portion of toner particles is used as the sample. The sample is prepared by diluting the toner particles with chloroform to a concentration of 0.1% by mass, and the solution is filtered through a 0.45 μm PTFE filter before being used for measurement. The gradient polymer LC measurement conditions are shown below. Equipment: UlTIMATE3000 (manufactured by Thermo Fisher Scientific) Mobile phase: A. Chloroform (HPLC), B. Acetonitrile (HPLC) Gradient: 2 min (A / B=0 / 100) → 25 min (A / B=100 / 0) (Note that the gradient of the mobile phase change was made to be a straight line.) Flow rate: 1.0mL / min Injection: 0.1% by mass x 20μL Column: Tosoh TSKgel ODS (4.6mmφ x 150mm x 5μm) Column temperature: 40℃ Detector: Corona Charged Particle Detector (Corona-CAD) (manufactured by Thermo Fisher Scientific)

[0101] The time-intensity graph obtained from the measurement shows that the resin components can be separated into two peaks depending on their polarity. Subsequently, by repeating the above measurement and sampling at the time of the trough of each peak, it is possible to separate them into two types of resin. In this measurement, components with higher solubility in acetonitrile elute earlier. Therefore, the binder resin and olefin unit-containing polystyrene resin B elute in that order. By identifying the peaks corresponding to each resin and sampling at that timing, fractions containing the binder resin and olefin unit-containing polystyrene resin B are collected. After drying and concentration, the sample of olefin unit-containing polystyrene resin B is obtained. Note that the same procedure can be performed to collect each fraction from toner particles containing components other than the binder resin and olefin unit-containing polystyrene resin B.

[0102] If the toner contains a release agent, it is necessary to separate the release agent from the toner. The release agent is separated by recycled HPLC, which isolates components with a molecular weight of 2000 or less. The measurement method is as follows: First, a chloroform solution of the toner is prepared using the method described above. Then, the obtained solution is filtered through a solvent-resistant membrane filter, "Myshoridisk" (manufactured by Tosoh Corporation), with a pore diameter of 0.2 μm, to obtain a sample solution. The sample solution is prepared so that the concentration of components soluble in chloroform is 1.0% by mass. This sample solution is then measured under the following conditions. ·Equipment: LC-Sakura NEXT (manufactured by Nippon Analytical Industry Co., Ltd.) • Columns: JAIGEL2H, 4H (manufactured by Nippon Analytical Engineering Co., Ltd.) • Eluent: Chloroform ·Flow rate: 10.0mL / min Oven temperature: 40.0℃ • Sample injection volume: 1.0 mL

[0103] To calculate the molecular weight of the sample, a molecular weight calibration curve created using standard polystyrene resin (for example, "TSK Standard Polystyrene F-850, F-450, F-288, F-128, F-80, F-40, F-20, F-10, F-4, F-2, F-1, A-5000, A-2500, A-1000, A-500", manufactured by Tosoh Corporation) is used.

[0104] From the molecular weight curve obtained in this way, components with a molecular weight of 2000 or less are repeatedly separated, and the release agent is removed from the toner.

[0105] <Identification of olefin unit C in olefin unit-containing polystyrene resin B> The identification of olefin unit C in olefin unit-containing polystyrene resin B and the measurement of its content ratio are as follows: 1 The procedure is performed using H-NMR under the following conditions. Measuring device: FT NMR device JNM-EX400 (manufactured by JEOL Ltd.) Measurement frequency: 400MHz Pulse condition: 5.0 μs Frequency range: 10500Hz Total number of times: 64 Measurement temperature: 30℃ Sample: Place 50 mg of the sample to be measured into a sample tube with an inner diameter of 5 mm, add deuterated chloroform (CDCl3) as a solvent, and dissolve in a constant temperature bath at 40°C to prepare the sample.

[0106] obtained 1 The H-NMR chart is analyzed to identify the structure of each monomer unit. 1 In the 1H-NMR chart, a peak independent of the peaks attributed to the components of olefin unit C is selected from among the peaks attributed to the components of other monomer units, and the integral value S1 of this peak is calculated. The integral values ​​are similarly calculated for the other monomer units contained in the olefin unit-containing polystyrene resin B.

[0107] When the monomer units constituting the olefin unit-containing polystyrene resin B consist of olefin unit C and one other monomer unit, the content ratio of olefin unit C is determined as follows using the integral value S1 and the integral value S2 of the peak of the other monomer unit. Note that n1 and n2 are the number of hydrogen atoms in the constituent element to which the peak of interest belongs for each part. Olefin unit C content (mol%) = {(S1 / n1) / ((S1 / n1)+(S2 / n2))}×100

[0108] The same method can be used to calculate the content ratio of olefin unit C even when there are two or more other monomer units.

[0109] Furthermore, if a polymerizable monomer is used in which no hydrogen atoms are present in any component other than the vinyl group, 13 The atomic nuclei were measured using C-NMR. 13 Let C be used, and the measurement will be performed in single-pulse mode. 1It is calculated in the same manner by \(^1H\)-NMR. The ratio (mol%) of each monomer unit calculated by the above method is multiplied by the molecular weight of each monomer unit to convert the content ratio of each monomer unit to mass%.

[0110] That the olefin unit-containing polystyrene resin B is a block copolymer having a polyolefin segment and a polystyrene segment can be confirmed from the ratio of the peak derived from the carbon atom between olefin units, the peak derived from the carbon atom between styrene units, and the peak derived from the carbon atom between a styrene unit and an olefin unit in the \(^{13}C\)-NMR chart obtained by the above method. As an example, the carbon atom between olefin units is shown in formula (8), the carbon atom between styrene units is shown in formula (9), and the carbon atom between a styrene unit and an olefin unit is shown in formula (10). In formulas (8) to (10), the carbon atom indicated by the arrow corresponds to the aforementioned carbon atom. 13 That the olefin unit-containing polystyrene resin B is a block copolymer having a polyolefin segment and a polystyrene segment can be confirmed from the ratio of the peak derived from the carbon atom between olefin units, the peak derived from the carbon atom between styrene units, and the peak derived from the carbon atom between a styrene unit and an olefin unit in the \(^{13}C\)-NMR chart obtained by the above method. As an example, the carbon atom between olefin units is shown in formula (8), the carbon atom between styrene units is shown in formula (9), and the carbon atom between a styrene unit and an olefin unit is shown in formula (10). In formulas (8) to (10), the carbon atom indicated by the arrow corresponds to the aforementioned carbon atom.

[0111] Specifically, when the ratio value (S I / S SI ) of the integral value (S I ) of the peak derived from the carbon atom between olefin units and the integral value (S SI ) of the peak derived from the bond between a styrene unit and an olefin unit is 10 or more, and the ratio value (S S / S SI ) of the integral value (S S ) of the peak derived from the carbon atom between styrene units and the integral value (S SI ) of the peak derived from the bond between a styrene unit and an olefin unit is 5 or more, it is determined that the olefin unit-containing polystyrene resin B is a block copolymer having a polyolefin segment and a polystyrene segment.

[0112] Also, regarding that the polyolefin segment contains an olefin unit C, it can be determined from the peak position of the \(^{13}C\)-NMR chart. 13 It can be determined from the peak position of the \(^{13}C\)-NMR chart.

[0113] [ka]

[0114] <Method for measuring the average circularity of toner (particles)> To measure the average circularity of toner or toner particles, a flow-type particle image analyzer, the "FPIA-3000" (manufactured by Sysmex Corporation), is used, and measurements are taken under the measurement and analysis conditions used during calibration. To 20 mL of deionized water, appropriate amounts of surfactant and alkylbenzene sulfonate are added as dispersants. Then, 0.02 g of the sample to be measured is added, and the mixture is dispersed for 2 minutes using a tabletop ultrasonic cleaner / disperser (product name: VS-150, manufactured by Velvo-Clear Co., Ltd.) with an oscillation frequency of 50 kHz and an electrical output of 150 watts, to prepare the dispersion for measurement. During this process, the dispersion is cooled as needed to maintain a temperature of 10°C to 40°C. For measurement, the aforementioned flow-type particle image analyzer equipped with a standard objective lens (10x) is used, and the particle sheath "PSE-900A" (manufactured by Sysmex Corporation) is used as the sheath solution. The dispersion prepared according to the above procedure is introduced into the flow-type particle image analyzer, and 3000 toner (particles) are measured in HPF measurement mode and total count mode. The binarization threshold for particle analysis is set to 85%, and the analyzed particle diameter is limited to an equivalent circle diameter of 1.98 μm to 19.92 μm to determine the average circularity of the toner (particles). Before starting the measurement, autofocus adjustment is performed using standard latex particles (for example, Duke Scientific's 5100A (product name) diluted with deionized water). Thereafter, it is preferable to perform focus adjustment every two hours from the start of the measurement.

[0115] <Method for measuring weight-average particle size (D4) and number-average particle size (D1)> The weight-average particle size (D4) and number-average particle size (D1) of toner, toner particles, or toner matrix particles (hereinafter also referred to as toner, etc.) are calculated as follows.

[0116] The measuring device used is the "Coulter Counter Multisizer 3" (registered trademark, manufactured by Beckman Coulter, Inc.), a precision particle size distribution analyzer using the pore electrical resistance method equipped with a 100 μm aperture tube.

[0117] Setting measurement conditions and analyzing measurement data are performed using the included dedicated software, "Beckman Coulter Multisizer 3 Version 3.51" (manufactured by Beckman Coulter, Inc.). Measurements are performed using 25,000 effective measurement channels.

[0118] The electrolytic aqueous solution used for measurement is prepared by dissolving special grade sodium chloride in deionized water to a concentration of 1.0%, for example, "ISOTON II" (manufactured by Beckman Coulter, Inc.).

[0119] Before performing measurements and analysis, configure the dedicated software as follows.

[0120] In the dedicated software's "Change Standard Measurement Method (SOMME)" screen, set the total count in control mode to 50,000 particles, the number of measurements to 1, and the Kd value to the value obtained using "Standard Particle 10.0 μm" (manufactured by Beckman Coulter, Inc.). Press the "Measure Threshold / Noise Level Button" to automatically set the threshold and noise level. Also, set the current to 1,600 μA, the gain to 2, the electrolyte to ISOTON II, and check "Flush aperture tube after measurement".

[0121] In the dedicated software's "Pulse to Particle Size Conversion Settings" screen, set the bin spacing to logarithmic particle size, the particle size bins to 256 particle size bins, and the particle size range from 2 μm to 60 μm.

[0122] The specific measurement method is as follows: (1) Place 200.0 mL of electrolytic solution into a 250 mL round-bottom glass beaker specifically designed for the Multisizer 3, set it on the sample stand, and stir the mixture with the stirrer rod at 24 revolutions per second in a counterclockwise direction. Then, use the "Aperture Tube Flash" function of the dedicated software to remove any dirt and air bubbles from inside the aperture tube. (2) Place 30.0 mL of the electrolytic solution into a 100 mL flat-bottomed glass beaker. Add 0.3 mL of a diluted solution of "Contaminon N" (a 10% aqueous solution of a pH 7 neutral detergent for cleaning precision measuring instruments, consisting of a nonionic surfactant, anionic surfactant, and organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) diluted three times by mass with deionized water as a dispersant. (3) Prepare an ultrasonic dispersion system "Ultrasonic Dispersion System Tetora150" (manufactured by Nikko Bios Co., Ltd.) with an electrical output of 120W, which incorporates two oscillators with an oscillation frequency of 50kHz, with their phases shifted by 180 degrees. Add 3.3L of deionized water to the water tank of the ultrasonic dispersion system, and add 2.0mL of Contaminon N to this water tank. (4) Place the beaker from (2) above into the beaker fixing hole of the ultrasonic disperser and operate the ultrasonic disperser. Then, adjust the height of the beaker so that the resonance state of the liquid surface of the electrolytic solution inside the beaker is maximized. (5) While irradiating the electrolytic aqueous solution in the beaker described in (4) above with ultrasound, add 10 mg of toner or the like to the electrolytic aqueous solution little by little and disperse it. Continue the ultrasonic dispersion treatment for another 60 seconds. During the ultrasonic dispersion treatment, adjust the water temperature in the tank as appropriate so that it is between 10°C and 40°C. (6) Using a pipette, add the electrolytic aqueous solution (5) containing the dispersed toner, etc., to the round-bottom beaker (1) placed in the sample stand, adjusting the concentration to 5%. Continue measuring until the number of particles reaches 50,000. (7) The measurement data is analyzed using the dedicated software provided with the device to calculate the weight-average particle size (D4) and the number-average particle size (D1). Note that when the dedicated software is set to graph / volume %, the "Average Diameter" on the "Analysis / Volume Statistics (Arithmetic Mean)" screen is the weight-average particle size (D4). When the dedicated software is set to graph / number %, the "Average Diameter" on the "Analysis / Number Statistics (Arithmetic Mean)" screen is the number-average particle size (D1).

[0123] [Image forming apparatus] Figure 1 is a diagram showing a schematic configuration of an example of an image forming apparatus according to one aspect of the present disclosure. The overall configuration of the image forming apparatus will be described with reference to Figure 1. However, the components, dimensions, arrangement, etc. in this example configuration should be changed as appropriate and do not limit the scope of this invention. Figure 1 is a schematic cross-sectional view of an image forming apparatus 100, which is a laser printer capable of forming monochrome (black single-color) images using an electrophotographic method. The image forming apparatus 100 has a rotatable drum-shaped (cylindrical) photoreceptor (photosensitive drum) 11 as an electrostatic latent image carrier. When the image forming operation is started, the photoreceptor 11 is rotated in the direction of arrow A1 (clockwise direction) in the figure by the driving force transmitted from the drive motor, which is a drive source constituting the driving means.

[0124] The surface of the rotating photoreceptor 11 is uniformly charged to a predetermined potential with a predetermined polarity, which is the normal polarity of the toner, by a charging roller 21, which is a roller-type charging member acting as a charging means. The charging roller 21 has its surface (outer surface) in contact with the surface (outer surface) of the photoreceptor 11 to form a charged portion N2.

[0125] The charging roller 21 is pressed against the surface of the photoreceptor 11 with a predetermined pressure by springs at both ends in the direction of the rotation axis of a conductive support. The charging roller 21 rotates in conjunction with the rotation of the photoreceptor 11. During the charging process, a predetermined charging voltage (charging bias) is applied to the charging roller 21 at a predetermined timing from a charging power supply, which is a charging voltage application means (charging voltage application unit). The uniformly charged surface (non-image area) of the photoreceptor 11 becomes dark potential.

[0126] The surface of the charged photoreceptor 11 is scanned and exposed by an exposure device (laser exposure unit) 131, which acts as an exposure means (electrostatic image forming means), and an electrostatic latent image (electrostatic image) is formed on the photoreceptor 11. The exposure device 131 scans the surface of the photoreceptor 11 with a laser beam along the main scanning direction of the photoreceptor 11 (approximately parallel to the rotation axis direction of the photoreceptor 11) according to the image information (image data) to perform exposure. The exposure device 131 also repeats exposure along the main scanning direction along the sub-scanning direction (approximately parallel to the movement direction of the surface of the photoreceptor 11) in time with the image information. As a result, an electrostatic latent image is formed on the photoreceptor 11. The exposed surface of the photoreceptor 11, which is the exposed area (image area), becomes bright.

[0127] The electrostatic latent image formed on the photoreceptor 11 is developed (visualized) by a developing device (developing unit) 2, which is a developing means, when toner T is supplied as a developer, and a toner image (toner image, developer image) is formed on the photoreceptor 11. In this disclosure, a one-component toner is used as the developer contained in the developing device 2. Details of the toner are as described above.

[0128] The developing device 2 has a developing roller 31 as a toner carrier (developing member). During development, the surface (outer surface) of the developing roller 31 comes into contact with the surface (outer surface) of the photoreceptor 11 to form a developing section N1. Also during development, a predetermined developing voltage (developing bias) is applied to the developing roller 31 at a predetermined timing from a developing power supply, which is a developing voltage application means (developing voltage application section). Toner charged with the same polarity as the charging polarity of the photoreceptor 11 adheres to the exposed section (image section) on the photoreceptor 11, where the absolute value of the potential has decreased after uniform charging treatment and exposure (reverse developing method).

[0129] Development is performed by the potential difference (development contrast) formed between the development voltage applied to the developing roller 31 and the bright potential on the photoreceptor 11; therefore, a predetermined development voltage is applied to the developing roller 31. It is assumed that the surface potential formed on the surface of the developing roller 31 and the magnitude of the development voltage applied to the developing roller 31 are approximately the same. The developing roller 31 rotates in the direction of arrow A2 in the figure (counterclockwise) opposite to the direction of the photoreceptor 11 (the direction of movement at the contact point is forward). The developing device 2 will be further explained later.

[0130] Opposite the photoreceptor 11 is a transfer roller 111, which is a roller-type transfer member serving as a transfer means. The transfer roller 111 is pressed toward the photoreceptor 11, forming a transfer portion (transfer nip) N3, which is the contact area between the photoreceptor 11 and the transfer roller 111. The toner image formed on the photoreceptor 11 is transferred in the transfer portion N3 onto the recording material R, which is held and transported between the photoreceptor 11 and the transfer roller 111 by the action of the transfer roller 111. During transfer, a predetermined transfer voltage (transfer bias) is applied to the transfer roller 111 at a predetermined timing from a transfer power supply, which serves as a transfer voltage application means (transfer voltage application unit).

[0131] A sheet-like recording material (transfer material, recording medium, sheet) R, such as paper, is supplied from the paper feeding unit (feeding unit) 181 to the transfer unit N3. The paper feeding unit 181 may have a cassette as a recording material storage unit, transport rollers as transport members, etc. The recording material R is transported to the transfer unit N3 in timing with the toner image on the photoreceptor 11.

[0132] The recording material R onto which the toner image has been transferred is transported to a fixing device 121, which serves as a fixing means. The fixing device 121 applies heat and pressure to the recording material R carrying the unfixed toner image to fix (melt and solidify) the toner image to the recording material R. The recording material R with the fixed toner image is discharged (output) from the paper discharge unit (discharge unit) 191 and loaded onto a tray 192 located on the top of the image forming apparatus 100.

[0133] In this configuration example, the photoreceptor 11, the charging roller 21 acting as a process means on the photoreceptor 11, and the developing device 2 form a process cartridge 1 that can be attached to and detached from the image forming apparatus 100 as a single unit. The transfer roller 111, exposure device 131, fixing device 121, pre-exposure means 6, control unit 141 for controlling the developing device 2, and various power supplies are attached to the image forming apparatus 100. The image forming apparatus and process cartridge may have a cleaning blade (not shown) for cleaning the toner on the surface of the photoreceptor 11.

[0134] [Process Cartridge] Next, we will further explain process cartridge 1 in this configuration example.

[0135] The process cartridge 1 comprises a developing device (developing unit) 2 and a photoreceptor unit 3. The developing device 2, as will be described in detail later, includes a developing roller 31, a supply roller 32, a developing blade 33, and a developing container 36 which also serves as a developer container. The developing container 36 also serves as a developing frame that supports the developing roller 31, the supply roller 32, and the developing blade 33.

[0136] The photoreceptor unit 3 has a photoreceptor 11 and a charging roller 21, which are supported by each. The developing device 2 and the photoreceptor unit 3 are coupled such that the developing device 2 can pivot relative to the photoreceptor unit 3 about a rotation axis that is substantially parallel to the rotation axis direction of the photoreceptor 11. More specifically, the developing container (developing frame) 36 of the developing device 2 and the photoreceptor support container (photoreceptor unit frame) 61 of the photoreceptor unit 3 are pivotably coupled, thereby integrating the process cartridge 1.

[0137] As a result, the developing device 2 can move between a contact position where the developing roller 31 is in contact with the photoreceptor 11 and a separation position where the developing roller 31 is separated from the photoreceptor 11. By configuring the developing device 2 to be able to move between the contact position and the separation position, unnecessary wear of the developing device 2 and the photoreceptor 11 is suppressed. In other words, in the separation position, the rotation of the developing roller 31 and the supply roller 32 is stopped by stopping the drive of the developing device 2, thereby suppressing toner consumption, and wear of the charge transport layer is suppressed because the photoreceptor 11 no longer comes into contact with the developing roller 31.

[0138] [Developing equipment] Next, the developing device (developing unit) 2 in this configuration example will be further described. The developing device 2 has a developing roller 31 as a developing agent carrier (developing member) that carries and transports toner as a developing agent and supplies toner to the electrostatic latent image formed on the surface of the photoreceptor 11 to develop the electrostatic latent image. The developing device 2 also has a supply roller (supply stripping roller) 32 as a developing agent supply member (developing agent supply stripping member) that supplies toner to the developing roller 31 and also strips the toner from the developing roller 31. The supply roller 32 rotates in the direction of arrow A3.

[0139] Furthermore, the developing device 2 has a developing blade 33 as a regulating member that restricts the amount of toner supplied onto the developing roller 31 to a predetermined amount. The developing device 2 also has a developing container 36 that forms a toner storage section (toner container) 37 inside. One component of the developing agent, toner, is stored inside the toner storage section 37.

[0140] [Configurations included in embodiments of the present invention] This embodiment includes the following configuration. (Composition 1) A toner having toner particles containing a binder resin, an olefin unit-containing polystyrene resin B, and an ester wax A, The olefin unit-containing polystyrene resin B is a copolymer having an olefin unit and a styrene unit. The ester wax A is an ester compound having the above structure, The ester compound has an n-henicosyl group, an n-nonadecyl group, and an n-heptadecyl group as the n-alkyl group. A toner characterized in that, based on the total mass of the n-alkyl groups, the content of n-henicosyl groups is 50.0% by mass or more and 80.0% by mass or less, the content of n-nonadecyl groups is 5.0% by mass or more and 15.0% by mass or less, and the content of n-heptadecyl groups is 15.0% by mass or more and 30.0% by mass or less. (Configuration 2) The toner according to Configuration 1, wherein, based on the total mass of the n-alkyl groups, the content of n-henicosyl groups is 60.0% by mass or more and 70.0% by mass or less, the content of n-nonadecyl groups is 7.5% by mass or more and 15.0% by mass or less, and the content of n-heptadecyl groups is 20.0% by mass or more and 30.0% by mass or less. (Configuration 3) The toner according to Configuration 1 or 2, wherein the olefin unit-containing polystyrene resin B is a block copolymer of a polyolefin segment containing an olefin unit and a polystyrene segment. (Configuration 4) The toner according to any one of Configurations 1 to 3, wherein the binder resin is a styrene-acrylic copolymer. (Configuration 5) The toner according to any of Configurations 1 to 4, wherein the average circularity of the toner is 0.960 or more and 0.995 or less. (Configuration 6) The toner according to any one of Configurations 1 to 5, wherein the n-alkyl group further contains an n-pentadecyl group. (Configuration 7) The toner according to Configuration 6, wherein the content of the n-pentadecyl group is 0.1% by mass or more and 5.0% by mass or less, based on the total mass of the n-alkyl groups in the ester compound. (Composition 8) A process cartridge that can be attached to and detached from an image forming apparatus, The process cartridge is Toner and, A toner container for storing the toner, It has, The process cartridge is characterized in that the toner is the toner described in any of configurations 1 to 7. (Composition 9) Toner and, A toner carrier that holds the toner, Electrostatic latent image carrier, A charging means for charging the surface of the electrostatic latent image carrier with a charging member, An electrostatic latent image forming means for forming an electrostatic latent image on a charged electrostatic latent image carrier, Development: Using the toner to develop the electrostatic latent image and form a toner image on the electrostatic latent image carrier. means and A transfer means for transferring the toner image onto a recording medium, Fixing means for fixing the toner image transferred onto the recording medium onto the recording medium, An image forming apparatus comprising, The image forming apparatus is characterized in that the toner is the toner described in any of configurations 1 to 7. [Examples]

[0141] The present invention will be specifically described by the following examples. However, this does not limit the present invention in any way. The toner and the method for manufacturing the toner will be described below. Unless otherwise specified, all "parts" in the examples and comparative examples are based on mass.

[0142] <Example of manufacturing ester wax A-1> In a reaction vessel equipped with a thermometer, nitrogen inlet tube, stirrer, Dean-Stark trap, and Liebig condenser, 10 parts pentaerythritol, 62.5 parts behenic acid, 10.0 parts arachidic acid, 26.0 parts stearic acid, and 1.50 parts palmitic acid (total monocarboxylic acids equaling 1.05 molar equivalents of pentaerythritol) were added. The reaction was carried out at 220°C under a nitrogen stream at atmospheric pressure for 20 hours, while distilling off the water produced by the reaction, to obtain a crude esterification product. To this crude esterification product, 10 parts toluene and 5 parts isopropanol were added, and 15 parts of 10% potassium hydroxide aqueous solution in an amount equivalent to 1.5 times the acid value of the crude esterification product was added, and the mixture was stirred at 70°C for 30 minutes. After standing for 30 minutes, the aqueous phase was removed to complete the deoxidation process.

[0143] Next, 20 parts of deionized water were added to the obtained oil phase, and the mixture was stirred at 70°C for 30 minutes. After standing for 30 minutes, the aqueous phase was removed. The removed aqueous phase was washed with water four times until its pH became neutral. The oil phase after washing was drained under reduced pressure at 180°C and 1 kPa to remove the solvent, and then filtered to obtain the final target product, ester wax A-1.

[0144] <Manufacturing examples of ester wax A-2 to A-23> Ester waxes A-2 to A-23 were manufactured in the same manner as the manufacturing example for ester wax A-1, except that the amounts of behenic acid, arachidic acid, stearic acid, and palmitic acid used were changed to those listed in Table 1.

[0145] <Example of manufacturing ester wax A-24> Ester wax A-24 (melting point 75.5°C) was produced by mixing 62.5 parts of pentaerythritol tetrabehenate, 10.0 parts of pentaerythritol tetraarachilate, 26.0 parts of pentaerythritol tetrastearate, and 1.50 parts of pentaerythritol tetrapalminate.

[0146] [Table 1]

[0147] <Toner 1> (Process 1: Granulation process) • Styrene: 70 units n-butyl acrylate: 30 parts • Carbon black (manufactured by Mitsubishi Chemical Corporation, product name: #25B): 7 parts • Divinylbenzene: 0.6 parts t-dodecyl mercaptan: 1.2 parts • Polymethacrylate macromonomer (manufactured by Toa Gosei Chemical Co., Ltd., product name: AA6, Tg=94℃): 0.3 parts The above materials were mixed and wet-ground using a media-type wet grinder.

[0148] • Electrostatic charge control resin (manufactured by Fujikura Chemical Co., Ltd., product name: Acrybase FCA-207P, styrene / acrylic resin): 1 part • Ester wax A-1 (melting point 75.5℃): 15 parts • Olefin unit-containing polystyrene resin B-1 (manufactured by Kuraray Co., Ltd., product name: Hybler 5125, containing the structure of formula (1) as olefin unit C): 5 parts Subsequently, the above materials were added and mixed to obtain a polymerizable monomer composition.

[0149] On the other hand, in a stirred tank, at room temperature, an aqueous solution prepared by dissolving 7.4 parts of magnesium chloride (water-soluble polyvalent metal salt) in 250 parts of deionized water was gradually added under stirring to an aqueous solution prepared by dissolving 4.1 parts of sodium hydroxide (alkali metal hydroxide) in 50 parts of deionized water to prepare a magnesium hydroxide colloid (poorly water-soluble metal hydroxide colloid) dispersion.

[0150] On the other hand, 2 parts of methyl methacrylate (Tg=105°C) and 65 parts of deionized water were subjected to fine dispersion treatment using an ultrasonic emulsifier to obtain an aqueous dispersion of the polymerizable monomer for shells. The droplet size of the polymerizable monomer for shells was 1.6 μm for D90.

[0151] The polymerizable monomer composition was added to the magnesium hydroxide colloidal dispersion obtained as described above, and the mixture was stirred until the droplets stabilized. Then, 6 parts of t-butyl peroxyisobutyrate (manufactured by NOF Corporation, trade name: Perbutyl IB) were added as a polymerization initiator. Finally, the mixture was dispersed using an in-line emulsifying disperser (manufactured by Taiheiyo Kiko Co., Ltd., trade name: Milder) at a rotational speed of 15,000 rpm with high shear stirring while circulating, and droplets of the polymerizable monomer composition were formed.

[0152] (Step 2: Polymerization step) Next, 1 part of sodium tetraborate decahydrate was added to the aqueous dispersion of the polymerizable monomer composition formed into droplets, and the mixture was placed in a reactor equipped with a stirring blade. The temperature was raised to 85°C to carry out the polymerization reaction. After the polymerization conversion rate reached approximately 100%, the aqueous dispersion of the polymerizable monomer for the shell and 0.3 parts of 2,2'-azobis(2-methyl-N-(2-hydroxyethyl)-propionamide) (manufactured by Wako Pure Chemical Industries, Ltd., trade name: VA-086, water-soluble) were added to the reactor as a polymerization initiator for the shell. Polymerization was then continued for 4 hours to obtain a resin particle dispersion. In the above process, resin particles were formed excluding carbon black, charge control resin, olefin unit-containing polystyrene resin B-1, and ester wax A-1, and the glass transition temperature of the obtained resin particles was measured. The glass transition temperature was 53°C.

[0153] (Step 3: Volatile component removal step) The resin particle dispersion was heated to 100°C while continuing to stir, held at that temperature for 2 hours, and then cooled to remove volatile components.

[0154] (Post-processing: filtration, washing, and drying) The toner particle dispersion was washed with dilute sulfuric acid (25°C, 10 minutes) to reduce the pH to 4.5 or lower. Next, after separating the water by filtration, 200 parts of freshly deionized water were added to re-form a slurry. The water washing treatment (washing, filtration, and dewatering) was repeated several times at room temperature (25°C), and the resulting solid content was separated by filtration. Finally, the mixture was vacuum-dried to obtain toner particles 1.

[0155] To the toner particles obtained as described above in a 1:100 ratio, 1 part of hydrophobized silica microparticles (number average primary particle size of 7 nm) and 1 part of hydrophobized silica microparticles (number average primary particle size of 35 nm) were added as external additives. The mixture was then mixed and stirred using a high-speed stirrer (manufactured by Mitsui Mining Co., Ltd., product name: Henschel Mixer) to obtain Toner 1. The physical properties of Toner 1 (average circularity, weight-average particle size) are shown in Table 4.

[0156] <Toner 2-17, Toner 20-30> Toners 2-17 and 20-30 were obtained in the same manner as in the production example of toner 1, except that the raw materials and manufacturing conditions, including ester wax A listed in Table 1 and olefin unit-containing polystyrene resin B listed in Table 2, were changed to those listed in Table 3. The physical properties of these toners are shown in Table 4.

[0157] <Toner 18> The pulverized toner was manufactured using the following method.

[0158] • Binding resin: Styrene-n-butyl acrylate copolymer: 100 parts (Styrene-n-butyl acrylate copolymerization ratio = 70:30, Mp = 22000, Mw = 35000, Mw / Mn = 2.4, Tg = 55℃) • Carbon black (manufactured by Mitsubishi Chemical Corporation, product name: #25B): 7 parts • Electrostatic charge control resin (manufactured by Fujikura Chemical Co., Ltd., product name: Acrybase FCA-207P, styrene / acrylic resin): 1 part • Ester wax A-1: ​​15 parts • Polystyrene resin B-1 containing olefin units: 5 parts The above materials were pre-mixed in a Mitsui Henschel mixer, and then melt-kneaded in a twin-screw kneader (PCM-30, manufactured by Ikegai Iron Works Co., Ltd.) to obtain a compound. The obtained compound was cooled, coarsely ground in a hammer mill (manufactured by Hosokawa Micron Co., Ltd.), and then ground in a mechanical pulverizer (T-250, manufactured by Freund Turbo Industrial Co., Ltd.) to obtain a fine powder. The obtained fine powder was classified using a multi-part classifier utilizing the Coanda effect (EJ-L-3, manufactured by Nippon Steel Mining Co., Ltd.) to obtain toner particles. Toner particles were added to the obtained toner particles in the same manner as in the production example of toner 1 to obtain toner 18. The physical properties of toner 18 are shown in Table 4.

[0159] <Toner 19> Toner 19 was obtained in the same manner as the manufacturing example of toner 18, except that the classification process was omitted. The physical properties of toner 19 are shown in Table 4.

[0160] [Table 2]

[0161] [Table 3]

[0162] [Examples 1-24, Comparative Examples 1-6] The above toners 1-30 were used in the combinations shown in Table 4 for evaluation. The evaluation results are shown in Table 4.

[0163] The evaluation method and evaluation criteria of the present invention are described below.

[0164] As the image forming apparatus, a modified laser printer (product name: LBP-9650Ci, manufactured by Canon) was used, with a process speed of 250 mm / sec to 350 mm / sec and a fixing temperature of 120°C to 180°C. A process cartridge (product name: Toner Cartridge 323, manufactured by Canon) was also used.

[0165] The product toner was removed from the black cartridge, cleaned with compressed air, and then 250g of the toner of the present invention was filled in. The yellow, magenta, and cyan cartridges were each removed from their respective stations, and the toner level detection mechanisms were disabled before evaluation.

[0166] <Blocking resistance> 5g of toner was weighed into a poly cup and stored for 10 days in an environment of 55°C / 10%RH. Subsequently, the blocking resistance was evaluated based on the aggregation state of the toner according to the following evaluation criteria. A: No change. B: A small amount of clumping occurs, but it breaks down quickly. C: Some clumps may form, but they will break apart with a slight impact. D: Aggregates form and do not easily break apart. E: Completely aggregates and solidifies into a button shape.

[0167] <Evaluation of hot offset resistance> Under normal temperature and humidity conditions (25°C / 50%RH), the process speed was 260 mm / sec, and the fixing temperature was increased in 1°C increments while printing a solid image (toner application amount: 0.5 mg / cm²). 2 The transfer material was made from plain paper (Xerox 4200 paper, letter size, manufactured by Xerox, 75 g / m²). 2 The following criteria were used: ) The occurrence of hot offset was visually confirmed, and evaluated according to the temperature at which it occurred. A: Hot offset occurs at temperatures above 160℃. B: Hot offset occurs at temperatures between 155°C and 160°C. C: Hot offset occurs at temperatures between 150°C and 155°C. D: Hot offset occurs below 150℃

[0168] <Evaluation of cold offset resistance> Under normal temperature and humidity conditions (25°C / 50%RH), at a process speed of 260 mm / sec, while gradually lowering the fixing temperature in 1°C increments, a solid image (toner application amount: 0.9 mg / cm²) was created.2 The transfer material was made from plain paper (Xerox 4200 paper, letter size, manufactured by Xerox, 75 g / m²). 2 The following criteria were used: Cold offset was visually confirmed and evaluated based on the temperature at which it occurred. A: Minimum fixing temperature is less than 130°C B: Minimum fixing temperature is 130°C or higher but less than 135°C C: Minimum fixing temperature is 135°C or higher but less than 140°C D: Minimum fixing temperature exceeds 140°C

[0169] <Evaluation of development streaks> The durability test was conducted in a high-temperature, high-humidity environment (30°C / 80%RH) at a process speed of 350 mm / sec. The fixing temperature was adjusted to 150°C. Canon Marketing Japan's CS-680 was used as the durability paper, and the durability evaluation chart used an image with a 1.5% print density represented by horizontal lines. 21,000 images were printed using a sequence with a 4-second pause after every two prints. High-whiteness paper (product name: GF-C081, manufactured by Canon, 81.4 g / m²) was used. 2 Halftone images were printed out and the development streaks were evaluated. The cartridge was also disassembled and the number of streaks on the developing roller was counted. (Evaluation Criteria) A: No development streaks were found on the D roller (developing roller). Streaks appeared on the B:D roller (developing roller), but they are not visible in the halftones. Numerous streaks appeared on the C:D roller (developing roller), but they did not appear in the halftone image. Numerous streaks have appeared on the D:D roller (developing roller), and white streaks are also visible in the halftones.

[0170] <Evaluation of fixed image mottling> The evaluation paper is OCE RED LABEL, a rough paper (basis weight: 80g / m²). 2The following was used: Under normal temperature and humidity conditions (25°C / 50%RH), the process speed was set to 260 mm / sec, and 100 sheets of solid images with a print ratio of 100% were fed through on one side continuously. The fixing temperature was adjusted to 150°C.

[0171] The mottling in the obtained images was visually inspected and judged according to the following indicators. Mottling is a type of poorly fixed image where the melt viscosity of the toner image is too low, causing the paper's texture to become visible and resulting in a rough image. For evaluation, rough paper with a more uneven surface was used instead of plain paper. The occurrence of mottling was visually inspected and evaluated according to the following criteria. The number of rough sheets on which mottling occurred was also counted. A: No motoring occurred in any of the 100 images. B: Out of 100 sheets, 1 to 3 sheets have areas where motoring occurs. C: Out of 100 sheets, 4 to 9 sheets had areas where motoring occurred. D: Out of 100 sheets, more than 10 had areas where motoring occurred.

[0172] [Table 4] [Explanation of symbols]

[0173] 1: Process cartridge, 2: Developing device (developing means), 11: Photoreceptor (electrostatic latent image carrier), 21: Charging roller (charging means), 31: Developing roller (toner carrier), 37: Toner storage section (toner container), 100: Image forming apparatus, 111: Transfer roller (transfer means), 121: Fixing device (fixing means), 131: Exposure device (electrostatic latent image forming means), R: Recording material (recording medium), T: Toner

Claims

1. A toner having toner particles containing a binder resin, an olefin unit-containing polystyrene resin B, and an ester wax A, The olefin unit-containing polystyrene resin B is a copolymer having an olefin unit and a styrene unit. The ester wax A is an ester compound having the following structure, 【Chemistry 1】 (In the formula, R independently represents an n-alkyl group.) The ester compound has an n-hexicosyl group, an n-nonadecyl group, and an n-heptadecyl group as the n-alkyl group. A toner characterized in that, based on the total mass of the n-alkyl groups, the content of n-hexosil groups is 50.0% by mass or more and 80.0% by mass or less, the content of n-nonadecyl groups is 5.0% by mass or more and 15.0% by mass or less, and the content of n-heptadecyl groups is 15.0% by mass or more and 30.0% by mass or less.

2. The toner according to claim 1, wherein, based on the total mass of the n-alkyl groups, the content of n-henicosyl groups is 60.0% by mass or more and 70.0% by mass or less, the content of n-nonadecyl groups is 7.5% by mass or more and 15.0% by mass or less, and the content of n-heptadecyl groups is 20.0% by mass or more and 30.0% by mass or less.

3. The toner according to claim 1 or 2, wherein the olefin unit-containing polystyrene resin B is a block copolymer of a polyolefin segment containing an olefin unit and a polystyrene segment.

4. The toner according to claim 1 or 2, wherein the binder resin is a styrene-acrylic copolymer.

5. The toner according to claim 1 or 2, wherein the average circularity of the toner is 0.960 or more and 0.995 or less.

6. The toner according to claim 1 or 2, wherein the n-alkyl group further comprises an n-pentadecyl group.

7. The toner according to claim 6, wherein the content of the n-pentadecyl group is 0.1% by mass or more and 5.0% by mass or less, based on the total mass of the n-alkyl groups.

8. A process cartridge that can be attached to and detached from an image forming apparatus, The process cartridge is Toner and, A toner container for storing the toner, It has, A process cartridge characterized in that the toner is the toner described in claim 1 or 2.

9. Toner and, A toner carrier that holds the toner, Electrostatic latent image carrier, A charging means for charging the surface of the electrostatic latent image carrier with a charging member, An electrostatic latent image forming means for forming an electrostatic latent image on a charged electrostatic latent image carrier, Development: Using the toner to develop the electrostatic latent image and form a toner image on the electrostatic latent image carrier. means and A transfer means for transferring the toner image onto a recording medium, Fixing means for fixing the toner image transferred onto the recording medium onto the recording medium, An image forming apparatus comprising, The image forming apparatus is characterized in that the toner is the toner described in claim 1 or 2.

Images