Toner, two-component developer, and method for manufacturing toner

Abstract

To provide a toner that has charge stability even when images are output in a high-temperature and high-humidity environment and a normal-temperature and low-humidity environment over a long period and has good image density and image quality, a two-component developer, and a method for manufacturing toner.SOLUTION: A toner has toner particles containing a binder resin and silica particles on the surface of each of the toner particles, and contains the silica particles in an amount of 0.40 pts.mass or more and 3.50 pts.mass or less based on 100 pts.mass of the toner particles. The specific gravity of the silica particles is 1.7 g / cm3 or more. The ratio of carbon atoms in the silica particles obtained by an X-ray photoelectron spectroscope (ESCA) is 18 atom% or more.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to toners and two-component developers used in electrophotographic, electrostatic recording, electrostatic printing, and toner jet systems. [Background technology]

[0002] In recent years, with the widespread adoption of electrophotographic full-color photocopiers, there has been a growing demand for higher speeds, higher image quality, energy efficiency, and longer lifespans. Silica is a commonly known external additive used in toner. Generally, examples have been reported of surface-treated silica obtained by dry or wet (sol-gel) methods to enhance its hydrophobicity. For example, Patent Document 1 describes an example in which highly hydrophobic spherical sol-gel silica fine particles were added to toner matrix particles to improve the charge stability of the toner. However, when printing images over long periods in high-temperature, high-humidity environments, the silica present on the toner surface is affected by moisture, which can reduce the toner's charge and decrease image density and uniformity. Even when printing images over long periods in normal temperature, low-humidity environments, the silica present on the toner surface is affected by humidity, which can cause the toner to become excessively charged. In such cases, the toner may not fly away easily from the developing unit, resulting in decreased image density and uniformity, or the inability to obtain high-quality images. Thus, there was still room for improvement in terms of image density and image quality due to the toner's charge stability under different image output environments. On the other hand, Patent Document 2 describes an example in which polyalkylsilsesquioxane fine particles were added to toner matrix particles to improve the electrostatic stability of the toner. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2007-099582 [Patent Document 2] International Publication No. 2015 / 107961 [Overview of the project] [Problems that the invention aims to solve]

[0004] The inventors of this invention have found that the fine particles described in Patent Document 2 have a low specific gravity, resulting in insufficient adhesion to the toner matrix particles. This can cause excessive migration of the fine particles to the surface of the photoreceptor, leading to image defects such as double transfer (hereinafter referred to as ghosting). The object of the present invention is to provide a toner that solves the above problems. Specifically, the object is to provide a toner, a two-component developer, and a method for manufacturing the toner that have charge stability even when outputting images over a long period of time in high-temperature, high-humidity environments and normal-temperature, low-humidity environments, suppress ghosting, and have excellent image quality. [Means for solving the problem]

[0005] The present invention relates to toner particles containing a binder resin, and toner having silica particles on the surface of the toner particles, The silica particles are contained in an amount of 0.40 parts by mass or more and 3.50 parts by mass or less per 100 parts by mass of toner particles. The adhesion rate of the silica particles to the toner particles is 90% or more. The specific gravity of the silica particles is 1.7 g / cm³. 3 That's all. The percentage of carbon atoms in the aforementioned silica particles, as determined by X-ray photoelectron spectroscopy (ESCA), is 18 atom% or more. the law of nature, The silica particles are silica particles that have been hydrophobized with dimethyldimethoxysilane. This relates to a toner characterized by [something]. Furthermore, the present invention relates to a method for producing toner, comprising a mixing step of mixing toner particles containing a binder resin with silica particles to obtain a toner particle mixture, and a heat treatment step of heat treating the toner particle mixture with hot air, The toner contains 0.40 parts by mass or more and 3.50 parts by mass or less of the silica particles per 100 parts by mass of the toner particles. The adhesion rate of the silica particles to the toner particles is 90% or more. The specific gravity of the silica particles is 1.7 g / cm³. 3 That's all. The proportion of carbon atoms determined by X-ray photoelectron spectroscopy (ESCA) of the silica particles is 18 atom% or more the law of nature, The silica particles are treated with dimethyldimethoxysilane. It relates to a method for producing a toner, characterized in that it is like this. Furthermore, the present invention is a two-component developer having a toner and a magnetic carrier, It relates to a two-component developer, characterized in that the toner is the toner having the above configuration.

Effects of the Invention

[0006] According to the present invention, it is possible to provide a toner, a two-component developer, and a method for producing a toner that have charge stability even when outputting images in a high-temperature and high-humidity environment and a normal-temperature and low-humidity environment over a long period of time, suppress ghosting, and have excellent image quality.

Brief Description of the Drawings

[0007] [Figure 1] It is a diagram of a heat spheroidization treatment apparatus used in the present invention. [Figure 2] It is an explanatory diagram of a test chart used for evaluating ghosting.

Modes for Carrying Out the Invention

[0008] The toner of the present invention is a toner containing a binder resin and having silica particles on the surface of the toner particles, The silica particles are contained in an amount of 0.40 parts by mass or more and 3.50 parts by mass or less per 100 parts by mass of the toner particles, The specific gravity of the silica particles is 1.7 g / cm 3 or more, It is characterized in that the proportion of carbon atoms determined by X-ray photoelectron spectroscopy (ESCA) of the silica particles is 18 atom% or more.

[0009] Regarding the action and effect of using the toner of the present invention having such a configuration, the present inventors consider as follows.

[0010] Conventionally, silica particles used as external additives for toners are hydrophobized by coupling the silanol groups at their ends with silane compounds or by surface treatment with silicone oil. However, even after surface treatment, a large amount of silanol groups remain, and the proportion of carbon atoms in the outermost layer is low, resulting in reduced electrostatic stability. In contrast, the silica particles of the present invention have a large proportion of carbon atoms of 18 atoms or more, as determined by ESCA. This reduces the amount of silanol groups in the outermost layer, making them less susceptible to moisture and improving electrostatic stability. Furthermore, the increased uniformity of elements on the surface suppresses uneven charging between particles, improving image density stability and image quality under various conditions.

[0011] Furthermore, the silica particles of this invention have a specific gravity of 1.7 g / cm³. 3 The above features make it easier to apply force when fixing silica particles to toner matrix particles, improving adhesion and suppressing ghosting.

[0012] Furthermore, by keeping the silica particle content within a certain range (0.40 parts by mass or more and 3.50 parts by mass or less per 100 parts by mass of toner particles), the toner is sufficiently charged while suppressing the occurrence of ghosting caused by excessive silica particles.

[0013] The number-average particle size of the silica particles is preferably between 40 nm and 200 nm. Being within this range suppresses embedding and detachment of the toner when it is subjected to stress, improving charge stability and suppressing ghosting.

[0014] It is preferable that the silica-derived peak ratio, determined by peak separation of the Si2P spectrum measured by X-ray photoelectron spectroscopy (ESCA) of silica particles, is 40% or less of the total Si. This indicates that the proportion of tetrafunctional silane silicon in the outermost layer of the silica particles of the present invention is low, and being within this range improves the uniformity of the particle's charge, resulting in improved charge stability and image quality.

[0015] The adhesion rate of silica particles to the toner surface is preferably 80% or higher, and more preferably 90% or higher. If the adhesion rate of silica particles to the toner particle surface is low, not only will the charging ability decrease due to the detachment of silica particles from the toner particle surface when the toner is stressed by the magnetic carrier, but ghosting may occur due to the migration of silica particles to the photoreceptor surface. A method for measuring the adhesion rate of silica particles to toner particles by water washing will be described later.

[0016] It is preferable that the silica particles are treated with dimethyldimethoxysilane. Dimethyldimethoxysilane is a highly reactive bifunctional monomer, and it polymerizes while adsorbing onto the silica surface, creating a state where it covers the surface of the silica particles. As a result, while the silanol groups are located on the inside, the outermost layer has minimal exposure of silanol groups, thus suppressing excessive charging derived from the silanol groups while also suppressing water adsorption and stabilizing the charge.

[0017] The configuration of the toner of the present invention will be described in detail below.

[0018] <Silica particles> The silica particles have a specific gravity of 1.7 g / cm³. 3 As long as the proportion of carbon atoms determined by X-ray photoelectron spectroscopy (ESCA) is 18 atoms or more, there are no particular limitations, and known silica particles can be used. Specifically, examples include sol-gel silica particles, aqueous colloidal silica particles, alcoholic silica particles, fumed silica particles obtained by gas-phase methods, molten silica particles, and deflagration silica particles. Among these, sol-gel silica particles are preferred from the viewpoint of charge stability.

[0019] The silica particles undergo hydrophobic treatment, resulting in a carbon atom content of 18 atoms or more, as determined by X-ray photoelectron spectroscopy (ESCA). Examples of hydrophobic treatment agents include dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diphenyldimethoxysilane, and diphenyldiethoxysilane. Among these, dimethyldimethoxysilane is preferred from the viewpoint of the reactivity of the treatment agent.

[0020] Furthermore, it is preferable that the silica particles are treated with dimethyldimethoxysilane followed by trimethylsilylation. This allows for the removal of any remaining silanol after dimethyldimethoxysilane treatment, thereby improving electrostatic stability.

[0021] Examples of trimethylsilylating agents include trimethylsilanol, trimethylmethoxysilane, trimethylchlorosilane, and hexamethyldisilazane.

[0022] The carbon atom ratio and specific gravity of silica particles, determined by X-ray photoelectron spectroscopy (ESCA), can be adjusted by controlling the amount of these treatment agents and reaction conditions such as reaction time. It is preferable to use the surface treatment agent in an amount of 30 to 80 parts by mass per 100 parts by mass of silica. Within this range, the surface is treated appropriately while suppressing the decrease in specific gravity due to polymerization, improving charge stability, and preventing ghosting.

[0023] The following describes an example of the production of silica particles used in the present invention.

[0024] A tetrafunctional silane compound can be added dropwise to a mixed solvent of water and an organic solvent, hydrolysis and condensation reactions can be carried out with a catalyst, followed by the removal of the alcohol by distillation, and the resulting suspension can be filtered and dried. Examples of tetrafunctional silanes include tetramethoxysilane, tetraethoxysilane, and tetraisocyanatesilane.

[0025] The particle size can be controlled by the type of catalyst, the mixing ratio, the reaction initiation temperature, and the dropping time. Examples of acidic catalysts include hydrochloric acid, hydrofluoric acid, sulfuric acid, and nitric acid, while examples of basic catalysts include aqueous ammonia, sodium hydroxide, and potassium hydroxide, but the catalyst is not limited to these.

[0026] To prepare a basic aqueous medium, an organic solvent may be used in addition to the basic component and water. The organic solvent is not particularly limited as long as it is miscible with water, but an organic solvent that dissolves 10 g or more of water per 100 g at room temperature and atmospheric pressure is preferred.

[0027] Specifically, examples include compounds such as methanol, ethanol, n-propanol, 2-propanol, butanol, ethylene glycol, diethylene glycol, propylene glycol, glycerin, trimethylolpropane, hexanetriol, ethylene glycol monoethyl ether, acetone, diethyl ether, tetrahydrofuran, diacetone alcohol, dimethylformamide, dimethylacetamide, and N-methylpyrrolidone.

[0028] Among the organic solvents listed above, alcohol-based solvents such as methanol, ethanol, 2-propanol, and butanol are preferred. Furthermore, from the viewpoint of hydrolysis and dehydration condensation reactions, it is even more preferable to select the same alcohol as the alcohol produced by elimination as the organic solvent.

[0029] The silica particles used in the present invention are hydrophobically treated with the aforementioned treating agent on the particles thus obtained. Known techniques are used for the treatment method. For example, a solution containing the raw material of untreated silica fine particles is put into a treatment tank, and while adjusting the temperature of the treatment tank and stirring and mixing, a predetermined amount of a silane-based compound is dropped over time and reacted (first hydrophobization treatment). At this time, from the viewpoint of the balance between the reactivity with the silica raw material and the self-condensation reaction, the temperature in the treatment tank is preferably 60 to 80°C, the dropping time is preferably 20 minutes or more, and the treatment time is preferably 4 hours or more. Next, after adding a trimethylsilylating agent to perform the second hydrophobization treatment, the reaction is allowed to proceed sufficiently. Thereafter, the powder in the dispersion is recovered by suction filtration and dried under reduced pressure at 100 to 150°C to obtain silica particles.

[0030] <Other inorganic fine particles> The toner can further contain inorganic fine particles as necessary. The inorganic fine particles may be incorporated into the toner particles or mixed with the toner particles as an external additive. As the external additive, inorganic fine powders such as titanium oxide, aluminum oxide, and strontium titanate are preferable. The inorganic fine powder is preferably hydrophobized with a hydrophobizing agent such as a silane compound, silicone oil, or a mixture thereof.

[0031] As an external additive for improving fluidity, inorganic fine powders having a specific surface area of 50 m 2 / g or more and 400 m 2 / g or less are preferable. For durability stabilization, inorganic fine powders having a specific surface area of 10 m 2 / g or more and 50 m 2 / g or less are preferable. In order to achieve both improvement in fluidity and durability stabilization, inorganic fine powders having a specific surface area within the above range may be used in combination.

[0032] The external additive is preferably used in an amount of 0.1 part by mass or more and 10.0 parts by mass or less with respect to 100 parts by mass of the toner particles.

[0033] Methods for adding external additives include mixing toner particles with known external additives in predetermined amounts and stirring and mixing them using mixing equipment such as a double-con mixer, V-type mixer, drum-type mixer, super mixer, Henschel mixer, Nauta mixer, Mechanohybrid (manufactured by Nippon Coke Industries Co., Ltd.), or Novilta (manufactured by Hosokawa Micron Corporation) as an external additive machine.

[0034] <Binding resin> (Amorphous resin) The binder resin for toner particles in the present invention can be an amorphous resin and may be the following polymers: monopolymers of styrene and its substituted products such as polystyrene, poly-p-chlorostyrene, and polyvinyltoluene; styrene copolymers such as styrene-p-chlorostyrene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylic acid ester copolymer, and styrene-methacrylic acid ester copolymer; styrene copolymer resins, polyester resins, hybrid resins obtained by mixing polyester resin and vinyl resin, or by partially reacting both; polyvinyl chloride, phenolic resin, naturally modified phenolic resin, naturally modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin, xylene resin, polyethylene resin, and polypropylene resin.

[0035] Monomers used in polyester units of polyester resins include polyhydric alcohols (dihydric or trihydric or higher alcohols), polyhydric carboxylic acids (dihydric or trihydric or higher carboxylic acids), their acid anhydrides, or their lower alkyl esters. Here, partial crosslinking within the amorphous resin molecule is effective in creating branched polymers, and for this purpose, it is preferable to use polyfunctional compounds with a valency of trihydric or higher. Therefore, it is preferable that the raw material monomers for the polyester unit include trihydric or higher carboxylic acids, their acid anhydrides, or their lower alkyl esters, and / or trihydric or higher alcohols.

[0036] The following polyhydric alcohol monomers can be used as polyhydric alcohol monomers in the polyester units of polyester resin.

[0037] Examples of divalent alcohol components include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, hydrogenated bisphenol A, and bisphenols represented by formula (A) and their derivatives;

[0038] [ka] (In the formula, R is an ethylene or propylene group, x and y are integers greater than or equal to 0, and the average value of x + y is between 0 and 10.) Diols represented by formula (B);

[0039] [ka]

[0040] Examples of trivalent or higher alcohol components include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, and 1,3,5-trihydroxymethylbenzene. Of these, glycerol, trimethylolpropane, and pentaerythritol are preferred. These divalent and trivalent or higher alcohols can be used individually or in combination.

[0041] The following polycarboxylic acid monomers can be used as polycarboxylic acid monomers in the polyester units of polyester resins.

[0042] Examples of divalent carboxylic acid components include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, adipic acid, sebatic acid, azelaic acid, malonic acid, n-dodecenylsuccinic acid, isododecenylsuccinic acid, n-dodecylsuccinic acid, isododecylsuccinic acid, n-octenylsuccinic acid, n-octylsuccinic acid, isooctenylsuccinic acid, isooctylsuccinic acid, anhydrides of these acids, and lower alkyl esters thereof. Of these, maleic acid, fumaric acid, terephthalic acid, and n-dodecenylsuccinic acid are preferably used.

[0043] Examples of trivalent or higher carboxylic acids, their acid anhydrides, or their lower alkyl esters include 1,2,4-benzenetricarboxylic acid, 2,5,7-naphthalentricarboxylic acid, 1,2,4-naphthalentricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,2,4-cyclohexanetricarboxylic acid, tetra(methylenecarboxyl)methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, empole trimeric acid, their acid anhydrides, or their lower alkyl esters. Of these, 1,2,4-benzenetricarboxylic acid, i.e., trimellitic acid or its derivatives, is particularly preferred because it is inexpensive and easy to control the reaction. These divalent carboxylic acids and trivalent or higher carboxylic acids can be used individually or in combination.

[0044] The method for producing the polyester unit of the present invention is not particularly limited, and known methods can be used. For example, the aforementioned alcohol monomer and carboxylic acid monomer are charged simultaneously, and polymerization is carried out via an esterification reaction or transesterification reaction and a condensation reaction to produce a polyester resin. The polymerization temperature is not particularly limited, but a range of 180°C to 290°C is preferred. When polymerizing the polyester unit, polymerization catalysts such as titanium-based catalysts, tin-based catalysts, zinc acetate, antimony trioxide, and germanium dioxide can be used. In particular, the binder resin of the present invention is more preferably a polyester unit polymerized using a tin-based catalyst.

[0045] Furthermore, a polyester resin with an acid value of 5 mg KOH / g or more and 20 mg KOH / g or less, and a hydroxyl value of 20 mg KOH / g or more and 70 mg KOH / g or less is preferable from the viewpoint of image density stability because it can suppress the amount of moisture adsorbed in high temperature and high humidity environments.

[0046] Furthermore, the binder resin may be a mixture of a low molecular weight resin and a high molecular weight resin. From the viewpoint of low-temperature fixing properties and resistance to hot offset, the ratio of high molecular weight resin to low molecular weight resin is preferably 40 / 60 or more and 85 / 15 or less by mass.

[0047] (Crystalline resin) Crystalline resins may be used for the toner particles. Crystalline resins are resins in which an endothermic peak is observed in differential scanning calorimetry (DSC).

[0048] The crystalline resin is not particularly limited, but from the viewpoint of low-temperature fixation properties, it is preferable that the main component be a polyester resin.

[0049] The crystalline polyester is preferably obtained by polycondensation reaction of a monomer composition mainly comprising an aliphatic diol having 2 to 22 carbon atoms and an aliphatic dicarboxylic acid having 2 to 22 carbon atoms.

[0050] The aliphatic diol having 2 to 22 carbon atoms (more preferably 6 to 12 carbon atoms) is not particularly limited, but it is preferably a linear aliphatic diol (more preferably a straight-chain aliphatic diol).

[0051] Examples include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, 1,4-butanediol, 1,4-butadiene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, nonamethylene glycol, decamethylene glycol, and neopentyl glycol.

[0052] Among these, linear aliphatic and α,ω-diols such as ethylene glycol, diethylene glycol, 1,4-butanediol, and 1,6-hexanediol are particularly preferred examples.

[0053] Of the above alcohol components, preferably 50% by mass or more, and more preferably 70% by mass or more, are alcohols selected from aliphatic diols having 2 to 22 carbon atoms.

[0054] Other polyhydric alcohol monomers besides the aliphatic diols mentioned above can also be used. Examples of dihydric alcohol monomers among these polyhydric alcohol monomers include aromatic alcohols such as polyoxyethylene-bisphenol A and polyoxypropylene-bisphenol A; and 1,4-cyclohexanedimethanol. Examples of trihydric or higher polyhydric alcohol monomers among these polyhydric alcohol monomers include aromatic alcohols such as 1,3,5-trihydroxymethylbenzene; and aliphatic alcohols such as pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerin, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, and trimethylolpropane.

[0055] Furthermore, a monovalent alcohol may be used to the extent that it does not impair the properties of the crystalline polyester. Examples of such monovalent alcohols include monoalcohols such as n-butanol, isobutanol, sec-butanol, n-hexanol, n-octanol, 2-ethylhexanol, cyclohexanol, and benzyl alcohol.

[0056] On the other hand, the aliphatic dicarboxylic acid having 2 to 22 carbon atoms (more preferably 6 to 12 carbon atoms) is not particularly limited, but it is preferably a linear aliphatic dicarboxylic acid.

[0057] Specific examples include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, superiric acid, glutaconic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, maleic acid, fumaric acid, mesaconic acid, citraconic acid, and itaconic acid, as well as hydrolyzed acid anhydrides or lower alkyl esters of these acids.

[0058] Of the above carboxylic acid components, preferably 50% by mass or more, more preferably 70% by mass or more, is a carboxylic acid selected from aliphatic dicarboxylic acids having 2 to 22 carbon atoms.

[0059] Other polycarboxylic acids besides the aliphatic dicarboxylic acids with 2 to 22 carbon atoms mentioned above can also be used. Among the other polycarboxylic acid monomers, divalent carboxylic acids include aromatic carboxylic acids such as isophthalic acid and terephthalic acid; aliphatic carboxylic acids such as n-dodecylsuccinic acid and n-dodecenylsuccinic acid; and alicyclic carboxylic acids such as cyclohexanedicarboxylic acid. These also include their acid anhydrides or lower alkyl esters.

[0060] Furthermore, among other carboxylic acid monomers, polycarboxylic acids with a valency of 3 or higher include aromatic carboxylic acids such as 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalentricarboxylic acid, 1,2,4-naphthalentricarboxylic acid, and pyromellitic acid, as well as aliphatic carboxylic acids such as 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, and 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane. These also include derivatives such as acid anhydrides or lower alkyl esters.

[0061] Furthermore, the material may contain a monovalent carboxylic acid to an extent that does not impair the properties of the crystalline polyester. Examples of monovalent carboxylic acids include monocarboxylic acids such as benzoic acid, naphthalenecarboxylic acid, salicylic acid, 4-methylbenzoic acid, 3-methylbenzoic acid, phenoxyacetic acid, biphenylcarboxylic acid, acetic acid, propionic acid, butyric acid, and octanoic acid.

[0062] Furthermore, from the viewpoint of low-temperature fixability and storage properties, it is preferable that the crystalline polyester resin is a crystalline polyester resin in which one or more aliphatic compounds selected from the group consisting of aliphatic monocarboxylic acids and aliphatic monoalcohols having 10 to 20 carbon atoms are condensed at the ends of the molecular chain.

[0063] Generally, in the recrystallization of crystalline polyesters, crystals grow starting from crystal nuclei. Therefore, by condensing one or more aliphatic compounds selected from the group consisting of aliphatic monocarboxylic acids and aliphatic monoalcohols with 10 to 20 carbon atoms at the end of the molecular chain, these act as crystal nuclei, promoting recrystallization and thus improving storage properties.

[0064] Furthermore, when the number of carbon atoms is within the above range, it is easy to condense them at the ends of the molecular chain, and they no longer exist as free monomers, which is preferable from the viewpoint of storage properties. Also, when the number of carbon atoms is within the above range, the compatibility between crystalline polyester and amorphous resin is not impaired, which is preferable from the viewpoint of low-temperature fixation properties.

[0065] Furthermore, the amount of one or more aliphatic compounds selected from the group consisting of aliphatic monocarboxylic acids and aliphatic monoalcohols having 10 to 20 carbon atoms is preferably 1.0 mol% to 10.0 mol%, and more preferably 4.0 mol% to 8.0 mol%, in the raw material monomer of the crystalline polyester resin. An amount of aliphatic compound within this range is preferable because it allows for the presence of an appropriate amount of crystal nuclei without inhibiting low-temperature fixation.

[0066] Aliphatic monocarboxylic acids with 10 to 20 carbon atoms include capric acid (decanoic acid), undecylic acid, lauric acid (dodecanoic acid), tridecylic acid, myristyl acid (tetradecanoic acid), pentadecylic acid, palmitic acid (hexadecanoic acid), margaric acid (heptadecanoic acid), stearic acid (octadecanoic acid), nonadecylic acid, and arachidic acid (eicosanic acid).

[0067] Examples of aliphatic monoalcohols with 10 to 20 carbon atoms include caprylic alcohol (decanol), undecanol, lauryl alcohol (dodecanol), tridecanol, myristyl alcohol (tetradecanol), pentadecanol, palmityl alcohol (hexadecanol), margaryl alcohol (heptadecanol), stearyl alcohol (octadecanol), nonadecanol, and arachidyl alcohol (icosanol).

[0068] The content of crystalline polyester resin is preferably 3 parts by mass or more and 20 parts by mass or less per 100 parts by mass of amorphous resin, from the viewpoint of low-temperature fixability and electrostatic properties in high-temperature and high-humidity environments.

[0069] Crystalline polyesters can be produced according to conventional polyester synthesis methods. For example, crystalline polyesters can be obtained by esterifying or transesterifying the aforementioned carboxylic acid monomer and alcohol monomer, followed by a polycondensation reaction under reduced pressure or by introducing nitrogen gas, according to conventional methods. Subsequently, the desired crystalline polyester can be obtained by adding the above-mentioned aliphatic compound and carrying out an esterification reaction.

[0070] The above esterification or transesterification reactions can be carried out using conventional esterification or transesterification catalysts such as sulfuric acid, titanium butoxide, dibutyltin oxide, manganese acetate, or magnesium acetate, as needed.

[0071] Furthermore, the above polycondensation reaction can be carried out using conventional polymerization catalysts, such as known catalysts like titanium butoxide, dibutyltin oxide, tin acetate, zinc acetate, tin disulfide, antimony trioxide, and germanium dioxide. The polymerization temperature and catalyst amount are not particularly limited and can be determined as appropriate.

[0072] In esterification, transesterification, or polycondensation reactions, methods such as charging all monomers at once to increase the strength of the resulting crystalline polyester, or first reacting divalent monomers and then adding trivalent or higher monomers to reduce the amount of low molecular weight components, may be used.

[0073] <Release agent> Examples of release agents that can be used in the toner of the present invention include: hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, alkylene copolymers, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax; oxides of hydrocarbon waxes such as oxidized polyethylene wax or block copolymers thereof; waxes mainly composed of fatty acid esters such as carnauba wax; and deoxidized fatty acid esters such as deoxidized carnauba wax, which are partially or completely deoxidized.

[0074] Furthermore, the following can be listed: saturated linear fatty acids such as palmitic acid, stearic acid, and montanic acid; unsaturated fatty acids such as brassic acid, eleostearic acid, and valinalic acid; saturated alcohols such as stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnaubyl alcohol, ceryl alcohol, and melissyl alcohol; polyhydric alcohols such as sorbitol; esters of fatty acids such as palmitic acid, stearic acid, behenic acid, and montanic acid with alcohols such as stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnaubyl alcohol, ceryl alcohol, and melissyl alcohol; fatty acid amides such as linoleic acid amide, oleic acid amide, and lauric acid amide; methylenebisstearate amide, ethylenebiscaprate amide, ethylenebislaurate amide, and hexamethylene Saturated fatty acid bisamides such as bis-stearamide; unsaturated fatty acid amides such as ethylenebisoleamide, hexamethylenebisoleamide, N,N'dioleyladipamide, and N,N'dioleylsebacamide; aromatic bisamides such as m-xylenebis-stearamide and N,N'distearylisophthalamide; aliphatic metal salts (commonly known as metal soaps) such as calcium stearate, calcium laurate, zinc stearate, and magnesium stearate; waxes grafted onto aliphatic hydrocarbon waxes with vinyl monomers such as styrene or acrylic acid; partially esterified fatty acids and polyhydric alcohols such as behenic acid monoglyceride; and methyl ester compounds having hydroxyl groups obtained by hydrogenation of vegetable oils.

[0075] Among these waxes, hydrocarbon waxes such as paraffin wax and Fischer-Tropsch wax, or fatty acid ester waxes such as carnauba wax are preferred from the viewpoint of improving low-temperature fixation and fixation separation properties.

[0076] In the present invention, it is preferable that the wax is used in an amount of 3 parts by mass or more and 8 parts by mass or less per 100 parts by mass of the binder resin.

[0077] Furthermore, in the endothermic curve measured by a differential scanning calorimetry (DSC) device during heating, the peak temperature of the wax's maximum endothermic peak is preferably between 60°C and 110°C. A peak temperature within this range is preferable because it allows for both toner storage and resistance to hot offset.

[0078] <Wax dispersant> The toner of the present invention may contain a wax dispersant. The wax dispersant is not particularly limited, but from the viewpoint of wax dispersibility, it is preferably a polymer in which a styrene-acrylic polymer is graft-polymerized onto a polyolefin (hereinafter also referred to as a graft polymer). The polyolefin used in the graft polymer preferably has a peak temperature of the maximum thermal peak measured using a differential scanning calorimeter (DSC) of 60°C or more and 110°C or less. Furthermore, the polyolefin preferably has a weight-average molecular weight (Mw) of 900 or more and 50,000 or less.

[0079] Polyolefins are not particularly limited as long as they are polymers or copolymers of unsaturated hydrocarbons having one double bond, and various polyolefins can be used. Polyethylene and polypropylene are particularly preferred. Furthermore, from the viewpoint of reactivity during the production of graft polymers, it is more preferable to have a branched structure, such as polypropylene.

[0080] The polyolefin content is preferably 5.0% by mass to 20.0% by mass, and more preferably 8.0% by mass to 12.0% by mass, in the polymer in which a styrene-acrylic polymer is graft-polymerized onto the polyolefin.

[0081] In this invention, the method for graft polymerizing a styrene-acrylic polymer onto a polyolefin is not particularly limited, and conventionally known methods can be used. Preferably, the styrene-acrylic polymer has monomer units derived from cycloalkyl (meth)acrylate. Here, a monomer unit refers to the reacted form of the monomer substance in the polymer.

[0082] As the cycloalkyl (meth)acrylate, for example, the following cycloalkyl (meth)acrylate monomer (a) can be used.

[0083] Examples include cyclopropyl acrylate, cyclobutyl acrylate, cyclopentyl acrylate, cyclohexyl acrylate, cycloheptyl acrylate, cyclooctyl acrylate, cyclopropyl methacrylate, cyclobutyl methacrylate, cyclopentyl methacrylate, cyclohexyl methacrylate, cycloheptyl methacrylate, cyclooctyl methacrylate, dihydrocyclopentadiethyl acrylate, dicyclopentanyl acrylate, and dicyclopentanyl methacrylate.

[0084] Among these, from the viewpoint of hydrophobicity, at least one selected from the group consisting of cyclohexyl acrylate, cycloheptyl acrylate, cyclooctyl acrylate, cyclohexyl methacrylate, cycloheptyl methacrylate, and cyclooctyl methacrylate is preferred. These may be used individually or in combination.

[0085] In addition to cycloalkyl (meth)acrylate monomers (a), other monomers (b) may also be used in styrene-acrylic polymers. Examples include styrene monomers such as styrene, α-methylstyrene, p-methylstyrene, m-methylstyrene, p-methoxystyrene, p-hydroxystyrene, p-acetoxystyrene, vinyltoluene, ethylstyrene, phenylstyrene, and benzylstyrene; alkyl esters of unsaturated carboxylic acids (with 1 to 18 carbon atoms in the alkyl group) such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, and 2-ethylhexyl methacrylate; vinyl ester monomers such as vinyl acetate; vinyl ether monomers such as vinyl methyl ether; halogen-containing vinyl monomers such as vinyl chloride; and diene monomers such as butadiene and isobutylene. Multiple of these may be used.

[0086] <Coloring agent> The following are examples of colorants that can be contained in the toner of the present invention.

[0087] Examples of black colorants include carbon black and black colorants prepared by mixing yellow, magenta, and cyan colorants. While pigments may be used alone as colorants, using dyes and pigments in combination is preferable from the standpoint of full-color image quality to improve clarity.

[0088] The following are examples of pigments used for magenta toner: CI Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48:2, 48:3, 48:4, 49, 50, 51, 52, 53, 54, 55, 57:1, 58, 60, 63, 64, 68, 81:1, 83, 87, 88, 89, 90, 112, 114, 122, 123, 146, 147, 150, 163, 184, 202, 206, 207, 209, 238, 269, 282; CI Pigment Violet 19; CI Bat Red 1, 2, 10, 13, 15, 23, 29, 35.

[0089] Examples of dyes for magenta toner include: oil-soluble dyes such as CI Solvent Red 1, 3, 8, 23, 24, 25, 27, 30, 49, 81, 82, 83, 84, 100, 109, 121; CI Disperse Red 9; CI Solvent Violet 8, 13, 14, 21, 27; CI Disperse Violet 1; and basic dyes such as CI Basic Red 1, 2, 9, 12, 13, 14, 15, 17, 18, 22, 23, 24, 27, 29, 32, 34, 35, 36, 37, 38, 39, 40; and CI Basic Violet 1, 3, 7, 10, 14, 15, 21, 25, 26, 27, 28.

[0090] Examples of pigments for cyan toner include: CI Pigment Blue 2, 3, 15:2, 15:3, 15:4, 16, 17; CI Bat Blue 6; CI Acid Blue 45; and copper phthalocyanine pigments in which one to five phthalimidomethyl groups are substituted onto the phthalocyanine skeleton.

[0091] CI Solvent Blue 70 is a dye used for cyan toner.

[0092] The following pigments are used for yellow toner: CI Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 23, 62, 65, 73, 74, 83, 93, 94, 95, 97, 109, 110, 111, 120, 127, 128, 129, 147, 151, 154, 155, 168, 174, 175, 176, 180, 181, 185; CI Bat Yellow 1, 3, 20. CI Solvent Yellow 162 is a dye used for yellow toner.

[0093] The amount of coloring agent used is preferably 0.1 parts by mass or more and 30 parts by mass or less per 100 parts by mass of the binder resin.

[0094] <Charge control agent> The toner of the present invention may optionally contain a charge control agent. While known charge control agents can be used in the toner, metal compounds of aromatic carboxylic acids that are colorless, have a fast charging speed for the toner, and can stably maintain a constant charge are particularly preferred.

[0095] Examples of negative charge control agents include salicylate metal compounds, naphthoate metal compounds, dicarboxylic acid metal compounds, polymer compounds having sulfonic acid or carboxylic acid as a side chain, polymer compounds having sulfonate salts or sulfonic acid esters as a side chain, polymer compounds having carboxylate salts or carboxylic acid esters as a side chain, boron compounds, urea compounds, silicon compounds, and calixarenes. Examples of positive charge control agents include quaternary ammonium salts, polymer compounds having the aforementioned quaternary ammonium salts as a side chain, guanidine compounds, and imidazole compounds. The charge control agent may be added internally or externally to the toner particles. The amount of charge control agent added is preferably 0.05 parts by mass or more and 10 parts by mass or less per 100 parts by mass of binder resin.

[0096] <Developer> The toner of the present invention can be used as a one-component developer, but it is preferable to mix it with a magnetic carrier and use it as a two-component developer to further improve dot reproduction, and also to obtain stable images over a long period of time.

[0097] As magnetic carriers, generally known materials can be used, such as iron powder with an oxidized surface or iron powder without oxidation, metal particles such as iron, lithium, calcium, magnesium, nickel, copper, zinc, cobalt, manganese, chromium, and rare earth elements, their alloy particles, oxide particles, ferrite, and magnetic material dispersion resin carriers (so-called resin carriers) containing a magnetic material and a binder resin that holds the magnetic material in a dispersed state.

[0098] When the toner of the present invention is mixed with a magnetic carrier and used as a two-component developer, the carrier mixing ratio is preferably 2% by mass or more and 15% by mass or less, and more preferably 4% by mass or more and 13% by mass or less, as the toner concentration in the two-component developer, which usually yields good results.

[0099] <Manufacturing method> The toner particles of the present invention can be produced by known methods, such as dry methods including grinding, and wet methods including emulsification and agglutination, and dissolution and suspension.

[0100] The following describes an example of a toner manufacturing procedure using the grinding method.

[0101] In the raw material mixing process, predetermined amounts of other components such as binder resin (amorphous resin, or crystalline resin if necessary), wax, colorant, and charge control agent are weighed, blended, and mixed to form the toner particles. Examples of mixing equipment include double-con mixers, V-type mixers, drum-type mixers, super mixers, Henschel mixers, Nauta mixers, and Mechanohybrid (manufactured by Nippon Coke Industries Co., Ltd.).

[0102] Next, the mixed materials are melt-kneaded to disperse wax and other substances in the binder resin. The mixing and discharge temperature can be adjusted as appropriate depending on the binder resin and colorant used, but generally 100 to 180°C is preferred. In this melt-kneading process, batch-type kneaders such as pressure kneaders and Banbury mixers, or continuous kneaders can be used, and single-screw or twin-screw extruders are the mainstream due to their advantage of being able to produce continuously. Examples include the KTK twin-screw extruder (manufactured by Kobe Steel, Ltd.), the TEM twin-screw extruder (manufactured by Toshiba Machine Co., Ltd.), the PCM kneader (manufactured by Ikegai Iron Works Co., Ltd.), the twin-screw extruder (manufactured by KCK Co., Ltd.), the Co-kneader (manufactured by Buss Co., Ltd.), and the Nidex (manufactured by Nippon Coke Industries Co., Ltd.). Furthermore, the resin composition obtained by melt-kneading may be rolled with two rolls or the like and cooled with water in a cooling process.

[0103] Next, the cooled resin composition is pulverized to the desired particle size in a pulverization process. In the pulverization process, for example, it is coarsely pulverized using a pulverizer such as a crusher, hammer mill, or feather mill, and then further finely pulverized using a fine pulverizer such as a Kryptron system (manufactured by Kawasaki Heavy Industries), Super Rotor (manufactured by Nisshin Engineering Co., Ltd.), Turbo Mill (manufactured by Freund Turbo), or an air jet type pulverizer.

[0104] Subsequently, the material is classified as needed using classifiers and sieving machines such as the inertial classifier Elbow Jet (manufactured by Nippon Steel Mining Co., Ltd.), the centrifugal classifier Turboplex (manufactured by Hosokawa Micron Corporation), the TSP separator (manufactured by Hosokawa Micron Corporation), and the Faculty (manufactured by Hosokawa Micron Corporation) to obtain the classified product (toner particles). Among these, the Faculty (manufactured by Hosokawa Micron Corporation) is preferable because it can perform spheroidization of the toner particles simultaneously with classification, thereby improving transfer efficiency.

[0105] In the present invention, in order to control the adhesion rate of silica particles to the toner matrix particles in the water washing method of silica particles, it is preferable to mix the silica particles with the toner matrix particles to obtain a toner particle mixture and then perform heat treatment. For example, heat treatment can be performed using hot air with the heat treatment apparatus shown in Figure 1.

[0106] The mixture supplied in a fixed quantity by the raw material quantitative supply means 1 is guided by compressed gas adjusted by the compressed gas adjustment means 2 into an introduction pipe 3 installed vertically to the raw material supply means. The mixture that has passed through the introduction pipe is uniformly dispersed by a conical projection member 4 located in the center of the raw material supply means and guided into eight radially spreading supply pipes 5 and then into a processing chamber 6 where heat treatment is performed.

[0107] At this time, the flow of the mixture supplied to the processing chamber is restricted by a restricting means 9 installed within the processing chamber to regulate the flow of the mixture. As a result, the mixture supplied to the processing chamber is heat-treated while swirling within the processing chamber, and then cooled.

[0108] Hot air for heat-treating the supplied mixture is supplied from a hot air supply means 7 and introduced into the processing chamber in a spiral motion by a swirling member 13 for swirling the hot air. The swirling member 13 for swirling the hot air has multiple blades, and the swirling of the hot air can be controlled by the number and angle of the blades. The temperature of the hot air supplied into the processing chamber is preferably 110°C to 300°C at the outlet of the hot air supply means 7. If the temperature at the outlet of the hot air supply means is within the above range, it is possible to uniformly spheroidize the toner particles while preventing the toner particles from fusing or coalescing due to overheating of the mixture.

[0109] Furthermore, the heat-treated toner particles are cooled by cold air supplied from the cold air supply means 8. The temperature of the cold air supplied from the cold air supply means 8 is preferably -20°C to 30°C. If the temperature of the cold air is within this range, the heat-treated toner particles can be cooled efficiently, preventing fusion and coalescence of the heat-treated toner particles without hindering the uniform spheroidization process of the mixture. The absolute moisture content of the cold air is 0.5 g / m³. 3 More than 15.0g / m 3 The following is preferable:

[0110] Next, the cooled heat-treated toner particles are collected by a collection means 10 located at the lower end of the processing chamber. A blower (not shown) is provided at the end of the collection means, and the particles are transported by suction.

[0111] Furthermore, the powder particle supply port 14 is positioned so that the swirling direction of the supplied mixture and the swirling direction of the hot air are in the same direction, and the recovery means 10 of the surface treatment apparatus is positioned on the outer periphery of the processing chamber to maintain the swirling direction of the swirled powder particles. In addition, the cold air supplied from the cold air supply means 8 is configured to be supplied horizontally and tangentially from the outer periphery of the apparatus to the circumferential surface of the processing chamber. The swirling direction of the toner particles supplied from the powder supply port, the swirling direction of the cold air supplied from the cold air supply means, and the swirling direction of the hot air supplied from the hot air supply means are all in the same direction. As a result, turbulence does not occur in the processing chamber, the swirling flow within the apparatus is strengthened, a strong centrifugal force is applied to the toner particles, and the dispersibility of the toner particles is further improved, making it possible to obtain toner particles with fewer aggregated particles and a uniform shape.

[0112] The average circularity of the toner particles is preferably 0.950 to 0.980, more preferably 0.960 to 0.980. This range is preferable because it allows for both improved transferability and cleanability.

[0113] Next, the methods for measuring each physical property related to the present invention will be described.

[0114] <Separation of silica particles and toner matrix particles from toner> The physical properties of toner can also be measured using external additives separated by the following method: Add 200g of sucrose (manufactured by Kishida Chemical Co., Ltd.) to 100mL of deionized water and dissolve it in a water bath to prepare a concentrated sucrose solution. Place 31g of this concentrated sucrose solution and 6mL of Contaminon N (a 10% by mass 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.) into a centrifuge tube to prepare a dispersion. Add 1g of toner to this dispersion and break up any clumps of toner with a spatula or similar tool.

[0115] The centrifugation tube is shaken for 20 minutes at a rate of 350 strokes per minute using a shaker (Iwaki Sangyo Co., Ltd. "KM Shaker" (model: V.SX)). After shaking, the solution is transferred to a glass tube for a swing rotor (50 mL), and centrifugation is performed in a centrifuge at 3500 rpm for 30 minutes.

[0116] After centrifugation, toner matrix particles are present in the uppermost layer of the glass tube, while silica particles are present in the lower aqueous solution layer. The lower aqueous solution is collected and centrifuged to separate the sucrose from the silica particles, and the silica particles are collected. If necessary, centrifugation is repeated to ensure sufficient separation, then the dispersion is dried and the silica particles are collected. If multiple particles are added, silica particles can be selected using methods such as centrifugation.

[0117] <Method for measuring the specific gravity of silica particles> The specific gravity of silica particles is measured using a dry densimeter, AccuPic 1330 (manufactured by Shimadzu Corporation).

[0118] <Method for measuring the number-average particle size of silica particles> The number-average particle size of silica particles is measured using a transmission electron microscope (TEM) "JEM2800" (manufactured by JEOL).

[0119] First, the measurement sample was prepared. Approximately 5 mg of silica particles were mixed with 1 ml of isopropanol and dispersed in an ultrasonic disperser (ultrasonic cleaner) for 5 minutes. Next, one drop of the above dispersion was placed on a microgrid (150 mesh) with a support membrane for TEM, and the sample was dried to prepare the measurement sample.

[0120] Next, using a transmission electron microscope (TEM), images are acquired at a magnification (e.g., 200kV to 1Mx) that allows for sufficient measurement of silica particles in the field of view, under an acceleration voltage of 200kV. The particle size of 100 randomly selected silica particles is then measured to determine the number-average particle size. Particle size can be measured manually or using a measuring tool.

[0121] <Measurement of atom% of carbon atoms and peak ratio derived from silica by X-ray photoelectron spectroscopy (XPS; ESCA)> Fix the powder of silica particles to the sample stage of the XPS apparatus using an indium sheet and measure under the following conditions. Apparatus used: PHI 5000VersaProbe II manufactured by ULVAC-PHI, Inc. Irradiation ray: Al-Kα ray Output: 100μm, 25W, 15kV Photoelectron capture angle: 45° PassEnergy: 58.70 eV Stepsize: 0.125 eV Elements to be measured: All detected elements Measurement range: Powder 300μm × 200μm For the peaks obtained under the above conditions, by using the relative sensitivity factor provided by ULVAC-PHI, Inc., calculate the atom% of carbon atoms with respect to the total amount of constituent elements.

[0122] The peak ratio derived from silica is calculated by separating the peak derived from the silicon 2p orbital and dividing the peak area attributed to silica by the peak area of all peaks derived from the silicon 2p orbital.

[0123] <Method for measuring the fixing rate of toner particles by the water washing method of silica particles> (Water washing process) A dispersion was prepared by thoroughly mixing a sucrose aqueous solution (made by dissolving 20.7g of sucrose (manufactured by Kishida Chemical Co., Ltd.) in 10.3g of deionized water) and 6mL of Contaminon N (a pH 7 neutral detergent for cleaning precision measuring instruments, consisting of a nonionic surfactant, anionic surfactant, and organic builder) in a 30mL glass vial. For example, a glass vial such as VCV-30 (outer diameter: 35mm, height: 70mm) manufactured by Nichiden Rika Glass Co., Ltd. could be used. 1.0g of toner was added to this dispersion and allowed to stand until the toner settled naturally to prepare the pre-treatment dispersion. This pre-treatment dispersion was shaken for 5 minutes at a shaking speed of 200rpm using a shaker (YS-8D type: manufactured by Yayoi Co., Ltd.) to detach weakly adhering fine particles (silica particles) from the surface of the toner particles. Separation of the toner with strongly adhering fine particles remaining from the detached fine particles was performed using a centrifuge. The centrifugation process was carried out at 3700rpm for 30 minutes. The toner containing residual fine particles is collected by suction filtration, dried, and then washed with water to obtain the toner.

[0124] (Method for measuring adhesion rate) First, the amount of silica particles contained in the toner particles before water washing is quantified. This is done by measuring the Si element intensity in the toner particles using a wavelength-dispersive X-ray fluorescence analyzer, Axios advanced (PANalytical). Next, the Si element intensity in the toner particles after water washing is measured in the same manner. The adhesion rate (%) is: It can be calculated as (Si element intensity in toner particles after water washing / Si element intensity in toner particles before water washing) × 100.

[0125] <Method for measuring the weight-average particle size (D4) of toner particles or toner> The toner particles or the weight-average particle size (D4) of the toner are measured using the "Coulter Counter Multisizer 3" (registered trademark, manufactured by Beckman Coulter), a precision particle size distribution analyzer using the pore electrical resistance method with a 100 μm aperture tube, and the accompanying dedicated software "Beckman Coulter Multisizer 3 Version 3.51" (manufactured by Beckman Coulter) for setting measurement conditions and analyzing measurement data, with an effective measurement channel count of 25,000. The measurement data is then analyzed and calculated.

[0126] The electrolytic aqueous solution used for measurement is prepared by dissolving special grade sodium chloride in deionized water to a concentration of approximately 1% by mass; for example, "ISOTON II" (manufactured by Beckman Coulter) can be used.

[0127] Before performing measurements and analysis, configure the dedicated software as follows.

[0128] In the "Change Standard Measurement Method (SOM)" screen of the dedicated software, 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). Press the threshold / noise level measurement button to automatically set the threshold and noise level. Also, set the current to 1600 μA, the gain to 2, the electrolyte to ISOTON II, and check the box for flushing the aperture tube after measurement.

[0129] 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 to 2 μm or more and 60 μm or less.

[0130] The specific measurement method is as follows: (1) Place approximately 200 ml of the electrolytic solution into a 250 ml round-bottom glass beaker specifically designed for the Multisizer 3, set it on the sample stand, and stir with the stirrer rod at 24 revolutions per second in a counterclockwise direction. Then, use the "Aperture Flash" function of the analysis software to remove any dirt and air bubbles from inside the aperture tube. (2) Place approximately 30 ml of the electrolytic aqueous solution into a 100 ml flat-bottomed glass beaker, and add approximately 0.3 ml of a diluted solution of "Contaminon N" (a 10% by mass 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) Two oscillators with an oscillation frequency of 50 kHz are built in with a phase difference of 180 degrees, and a predetermined amount of deionized water is placed in the water tank of an ultrasonic disperser "Ultrasonic Dispension System Tetora150" (manufactured by Nikko Bios Co., Ltd.) with an electrical output of 120 W, and approximately 2 ml of the aforementioned Contaminon N is added to this water tank. (4) Place the beaker from (2) 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 aqueous solution inside the beaker is maximized. (5) While irradiating the electrolytic aqueous solution in the beaker described in (4) with ultrasound, add approximately 10 mg of toner to the electrolytic aqueous solution in small amounts and disperse it. Continue the ultrasonic dispersion treatment for another 60 seconds. During ultrasonic dispersion, adjust the water temperature in the tank to be between 10°C and 40°C as appropriate. (6) Using a pipette, the electrolyte aqueous solution from (5) containing dispersed toner is dropped into the round-bottom beaker from (1) placed in the sample stand, and the concentration is adjusted to approximately 5%. The measurement is then continued until the number of particles measured reaches 50,000. (7) The measurement data is analyzed using the dedicated software provided with the device, and the weight-average particle size (D4) is calculated. Note that the "Average Diameter" on the Analysis / Volume Statistics (Arithmetic Mean) screen when the dedicated software is set to Graph / Volume % is the weight-average particle size (D4).

[0131] <Method for measuring the average circularity of toner> The average circularity of the toner is measured using the flow-type particle image analyzer "FPIA-3000" (manufactured by Sysmex Corporation) under the measurement and analysis conditions used during calibration.

[0132] The measurement principle of the flow-type particle image analyzer "FPIA-3000" (manufactured by Sysmex Corporation) is to capture flowing particles as still images and perform image analysis. The sample added to the sample chamber is sent to the flat sheath flow cell by a sample aspiration syringe. The sample sent to the flat sheath flow cell is sandwiched between the sheath fluid and forms a flattened flow. A strobe light is irradiated onto the sample passing through the flat sheath flow cell at intervals of 1 / 60th of a second, making it possible to capture the flowing particles as still images. Furthermore, because it is a flattened flow, the images are captured in focus. The particle images are captured by a CCD camera, and the captured images are processed at an image processing resolution of 512 × 512 pixels (0.37 × 0.37 μm per pixel) to extract the contour of each particle image, and the projected area S and perimeter L of the particle image are measured.

[0133] Next, the equivalent diameter and circularity are determined using the area S and perimeter L mentioned above. The equivalent diameter is the diameter of a circle with the same area as the projected area of ​​the particle image, and the circularity C is defined as the value obtained by dividing the perimeter of the circle obtained from the equivalent diameter by the perimeter of the particle projection image, and is calculated by the following formula. Circularity C = 2 × (π × S)¹ / ² / L

[0134] When the particle image is circular, the circularity is 1.000, and the circularity decreases as the degree of unevenness around the outer edge of the particle image increases. After calculating the circularity of each particle, the range of circularity from 0.200 to 1.000 is divided into 800 parts, and the arithmetic mean of the obtained circularity values ​​is calculated and this value is taken as the average circularity.

[0135] The specific measurement method is as follows: First, about 20 ml of deionized water, from which impurities and other solids have been removed, is placed in a glass container. To this, about 0.2 ml of a diluted solution of "Contaminon N" (a 10% by mass 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 by about 3 times by mass with deionized water, is added as a dispersant. Then, about 0.02 g of the sample to be measured is added, and the dispersion treatment is performed for 2 minutes using an ultrasonic disperser to obtain the dispersion solution for measurement. At that time, the dispersion solution is cooled as appropriate so that its temperature is between 10°C and 40°C. As the ultrasonic disperser, a tabletop ultrasonic cleaner disperser with an oscillation frequency of 50 kHz and an electrical output of 150 W (for example, "VS-150" (manufactured by Velvo-Clear Co., Ltd.)) is used, a predetermined amount of deionized water is placed in the water tank, and about 2 ml of Contaminon N is added to this water tank.

[0136] For the measurement, a flow-type particle image analyzer equipped with a standard objective lens (10x) was used, and the particle sheath "PSE-900A" (manufactured by Sysmex Corporation) was used as the sheath solution. The dispersion solution prepared according to the procedure was introduced into the flow-type particle image analyzer, and 3000 toner particles were measured in HPF measurement mode and total count mode. Then, by setting the binarization threshold for particle analysis to 85% and specifying the particle diameter to be analyzed, the percentage of particles in that range and the average circularity can be calculated. The average circularity of the toner was determined with an equivalent circle diameter of 1.98 μm to 39.96 μm.

[0137] Before starting the measurement, autofocus adjustment should be performed using standard latex particles (for example, Duke Scientific's "RESEARCH AND TEST PARTICLES Latex Microsphere Suspensions 5200A" diluted with deionized water). Subsequently, it is preferable to perform focus adjustment every two hours from the start of the measurement.

[0138] In this embodiment, a flow-type particle image analyzer was used, which had been calibrated by Sysmex Corporation and for which a calibration certificate was issued by Sysmex Corporation. Except for limiting the analyzed particle size to a circular equivalent diameter of 1.98 μm or more and less than 39.69 μm, measurements were performed under the measurement and analysis conditions at the time the calibration certificate was issued.

[0139] [Configurations included in embodiments of the present invention] This embodiment includes the following configuration. (Configuration 1) A toner having toner particles containing a binder resin, and silica particles on the surface of the toner particles, The silica particles are contained in an amount of 0.40 parts by mass or more and 3.50 parts by mass or less per 100 parts by mass of toner particles. The specific gravity of the silica particles is 1.7 g / cm³. 3 That's all. A toner characterized in that the proportion of carbon atoms in the silica particles, as determined by X-ray photoelectron spectroscopy (ESCA), is 18 atom% or more. (Configuration 2) The toner according to Configuration 1, wherein the number-average particle size of the silica particles is 40 nm or more and 200 nm or less. (Configuration 3) The toner according to Configuration 1 or 2, wherein the silica-derived peak ratio, determined by peak separation of the Si2P spectrum measured by an X-ray photoelectron spectrometer (ESCA) of the silica particles, is 40% or less of the total Si. (Configuration 4) The toner according to any one of Configurations 1 to 3, wherein the adhesion rate of the silica particles to the toner particles is 90% or more. (Configuration 5) The toner according to any one of Configurations 1 to 4, wherein the silica particles are silica particles treated with hydrophobization using dimethyldimethoxysilane. (Configuration 6) A method for manufacturing toner, comprising a mixing step of mixing toner particles containing a binder resin with silica particles to obtain a toner particle mixture, and a heat treatment step of heat treating the toner particle mixture with hot air, The toner contains 0.40 parts by mass or more and 3.50 parts by mass or less of the silica particles per 100 parts by mass of the toner particles. The specific gravity of the silica particles is 1.7 g / cm³. 3That's all. A method for producing toner, characterized in that the proportion of carbon atoms in the silica particles, as determined by X-ray photoelectron spectroscopy (ESCA), is 18 atom% or more. (Configuration 7) The method for producing toner according to Configuration 6, wherein the silica particles are treated with dimethyldimethoxysilane. (Configuration 8) The method for producing toner according to Configuration 6, wherein the silica particles are treated with dimethyldimethoxysilane in an amount of 30 to 80 parts by mass per 100 parts by mass of silica raw material. (Configuration 9) A method for producing toner according to any one of Configurations 6 to 8, wherein the silica particles are treated with dimethyldimethoxysilane and then subjected to trimethylsilylation treatment. (Configuration 10) A two-component developer having toner and a magnetic carrier, A two-component developer characterized in that the toner is the toner described in any of components 1 to 5. [Examples]

[0140] The present invention will be described below with reference to examples. However, the description of these examples is not intended to limit the technical scope of this invention. Examples 5, 7, and 11 are for reference only. In addition, unless otherwise specified, all instances of "parts" in the examples and comparative examples refer to mass.

[0141] <Example of silica particle A1 manufacturing process> A catalyst solution was obtained by adding 500 parts methanol and 70 parts water, whose pH was adjusted to 5.4 using 10% hydrochloric acid, to a 1.5 L glass reaction vessel equipped with a stirrer, dropping nozzle, and thermometer, and mixing them. After adjusting this catalyst solution to 30°C, 100 parts tetramethoxysilane and 20 parts 8.0% aqueous ammonia were simultaneously added dropwise over 25 minutes while stirring, and stirring was continued for 30 minutes. Subsequently, the resulting silica particle dispersion was concentrated to a solid content of 40% by mass using a rotary filter R-Fine (manufactured by Kotobuki Kogyo Co., Ltd.) to obtain a silica particle dispersion. The particle size of the silica particles was 10 nm.

[0142] 250 parts of silica particle dispersion were adjusted to 70°C, then 60 parts of dimethyldimethoxysilane were added dropwise over 30 minutes, followed by a reaction at 70°C for 5 hours. Next, 5 parts of trimethylsilanol were added over 10 minutes, and the reaction was continued for another 2 hours. The powder in the dispersion was then collected by suction filtration and dried under reduced pressure at 120°C for 24 hours to obtain silica particles A1. The physical properties of the obtained silica particles A1 are shown in Table 1.

[0143] <Manufacturing examples of silica particles A2-A14> In the production example of silica particle A1, the particle size of the raw material was adjusted to the values ​​shown in Table 1 by adjusting the amount of tetramethoxysilane and aqueous ammonia added, the dropping time, and the reaction time. Silica particles A2 to A14 were obtained by similarly adjusting the surface treatment agent and its mass parts to the values ​​shown in Table 1. The physical properties of the obtained silica particles A2 to A14 are also shown in Table 1.

[0144] <Example of manufacturing silica particles A15> In the example of producing silica particles A8, silica particles A15 was obtained by adjusting the process in the same manner, except that the dropping time of dimethyldimethoxysilane was changed to 5 minutes and the processing temperature to 100°C. The physical properties of the obtained silica particles A15 are shown in Table 1.

[0145] [Table 1]

[0146] <Other examples of inorganic fine particle A16 production> Specific surface area of ​​200 g / m² 2 Inorganic fine particles A16 were obtained by surface-treating titanium oxide particles with i-butyltrimethoxysilane.

[0147] <Example of Amorphous Resin B Production> Polyoxypropylene(2,2)-2,2-bis(4-hydroxyphenyl)propane: 76.3 parts (0.19 moles; 100.0 mol% of the total moles of polyhydric alcohols) Terephthalic acid: 16.1 parts (0.10 moles; 60.0 mol% of the total moles of polycarboxylic acids) Succinic acid: 7.6 parts (0.06 moles; 40.0 mol% of the total moles of polycarboxylic acids) Titanium tetrabutoxide (esterification catalyst): 0.5 parts The above materials were weighed into a reaction vessel equipped with a condenser, stirrer, nitrogen inlet tube, and thermocouple. Next, the flask was purged with nitrogen gas, and the temperature was gradually increased while stirring. The reaction was carried out at 200°C with stirring for 4 hours.

[0148] Furthermore, the pressure inside the reaction vessel was reduced to 8.3 kPa and maintained for 1 hour, then cooled to 160°C and returned to atmospheric pressure (first reaction step).

[0149] • tert-butylcatechol (polymerization inhibitor): 0.1 part Subsequently, the above materials were added, the pressure in the reaction vessel was reduced to 8.3 kPa, and the reaction was allowed to proceed for 1 hour while maintaining the temperature at 180°C. After confirming that the softening point, measured according to ASTM D36-86, reached 90°C, the temperature was lowered to stop the reaction (second reaction step), and amorphous resin B was obtained.

[0150] <Example of Amorphous Resin C Manufacturing> Polyoxypropylene (2,2)-2,2-bis(4-hydroxyphenyl)propane: 73.8 parts Terephthalic acid: 12.5 parts • Adipic acid: 7.8 parts Titanium tetrabutoxide (esterification catalyst): 0.5 parts The above materials were weighed into a reaction vessel equipped with a condenser, stirrer, nitrogen inlet tube, and thermocouple. Next, the flask was purged with nitrogen gas, and the temperature was gradually increased while stirring. The mixture was then reacted at 200°C while stirring for 2 hours.

[0151] Furthermore, the pressure inside the reaction vessel was reduced to 8.3 kPa and maintained for 1 hour, then cooled to 160°C and returned to atmospheric pressure (first reaction step).

[0152] Trimellitus: 5.9 parts • tert-butylcatechol (polymerization inhibitor): 0.1 part Subsequently, the above materials were added, the pressure in the reaction vessel was reduced to 8.3 kPa, and the reaction was carried out for 15 hours while maintaining the temperature at 200°C. After confirming that the softening point, measured according to ASTM D36-86, had reached 140°C, the temperature was lowered to stop the reaction (second reaction step), and amorphous resin C was obtained.

[0153] <Example of manufacturing crystalline resin D> Hexanediol: 33.9 parts Dodecanedioic acid: 66.1 parts The above materials were weighed into a reaction vessel equipped with a condenser, stirrer, nitrogen inlet tube, and thermocouple. Next, the flask was purged with nitrogen gas, and the temperature was gradually increased while stirring. The reaction was carried out at 140°C with stirring for 3 hours. • Tin 2-ethylhexanoate: 0.5 parts Subsequently, the above materials were added, the pressure in the reaction vessel was reduced to 8.3 kPa, and the reaction was carried out for 4 hours while maintaining the temperature at 200°C to obtain crystalline resin D.

[0154] <Example of manufacturing wax dispersant E> • Low molecular weight polypropylene (Viscol 660P, manufactured by Sanyo Chemical Industries, Ltd.): 10.0 parts (0.4 mol% relative to the total number of moles of constituent monomers) Xylene: 25.0 parts The above materials were weighed into a reaction vessel equipped with a condenser, stirrer, nitrogen inlet tube, and thermocouple. Next, the flask was purged with nitrogen gas, and the temperature was gradually raised to 175°C while stirring.

[0155] Styrene: 68.0 parts (78.5 mol% of the total number of moles of constituent monomers) Cyclohexyl acrylate: 5.0 parts (3.9 mol% of the total number of moles of constituent monomers) Butyl acrylate: 12.0 parts (11.2 mol% relative to the total number of moles of constituent monomers) • Methacrylic acid: 5.0 parts (6.0 mol% relative to the total number of moles of constituent monomers) Xylene: 10.0 parts • Di-t-butylperoxyhexahydroterephthalate: 0.5 parts Subsequently, the above materials were added dropwise over 3 hours, and the mixture was stirred for another 30 minutes. Then, the solvent was removed by distillation to obtain wax dispersant E.

[0156] <Example of toner matrix particle 1 manufacturing> ·Amorphous resin B 60 parts ·Amorphous resin C 30 parts ·Crystalline resin D 10 parts • Wax dispersant E (4 parts) • Fischer-Tropsch wax (peak temperature of maximum endothermic peak: 90°C) 4 parts CI Pigment Blue 15:3 7 parts The above materials were mixed using a Henschel mixer (FM-75 model, manufactured by Mitsui Mining Co., Ltd.) at a rotation speed of 20 seconds. -1 After mixing for 5 minutes, the mixture was kneaded in a twin-screw kneader (PCM-30 model, manufactured by Ikegai Co., Ltd.) set to a temperature of 130°C. The resulting mixture was cooled and coarsely ground to less than 1 mm in a hammer mill to obtain coarse material. The obtained coarse material was finely ground in a mechanical pulverizer (T-250, manufactured by Turbo Kogyo Co., Ltd.). Further classification was performed using a Faculty F-300 (manufactured by Hosokawa Micron Corporation) to obtain toner mother particles 1. The operating conditions were a classification rotor rotation speed of 130 s. -1 , the distributed rotor rotation speed is 120s -1 The obtained toner matrix particles 1 had a weight-average particle size (D4) of 5.6 μm.

[0157] <Example of Toner 1 manufacturing> • Toner matrix particles 1,100 copies • Silica particles A1 1.0 part ·Inorganic fine particles A16 0.5 part The above ingredients are mixed in a Henschel mixer (FM-75 model, manufactured by Mitsui Miike Chemical Machinery Co., Ltd.) at a rotation speed of 30 seconds. -1 The mixture was then mixed for a rotation time of 5 minutes to obtain toner particles 1 before heat treatment.

[0158] The obtained pre-heat-treated toner particles 1 were heat-treated using the surface treatment apparatus shown in Figure 1 to obtain post-heat-treated toner particles 1. The operating conditions were a feed rate of 5 kg / hr, a hot air temperature of 160°C, and a hot air flow rate of 6 m³. 3 / min., cold air temperature = -5℃, cold air flow rate = 4m 3 / min., blower airflow = 20m 3 / min., injection air flow rate = 1m 3 I set it to / min.

[0159] • Heat-treated toner particles 1,100 units ·Inorganic fine particles A16 0.4 part The above ingredients are mixed in a Henschel mixer (FM-75 model, manufactured by Mitsui Miike Chemical Machinery Co., Ltd.) at a rotation speed of 30 seconds. -1 The mixture was mixed for a rotation time of 10 mins, then sieved through a mesh with a mesh opening of 55 μm to obtain toner 1. The weight-average particle size (D4) of toner 1 was 5.8 μm, and the average circularity was 0.970.

[0160] <Manufacturing examples for toners 2-18> Toners 2 to 18 were obtained in the same manner as in the manufacturing example of toner 1, except that the silica particles, other inorganic fine particles, their mass, and whether or not heat treatment was performed were changed as shown in Table 2-1.

[0161] Furthermore, Table 2-2 shows the adhesion rate of each silica particle (Toner 1-18) to the toner particles, as well as the weight-average particle size and average circularity of the toner.

[0162] [Table 2-1]

[0163] [Table 2-2]

[0164] <Example of manufacturing magnetic core particle 1> • Process 1 (Weighing and mixing process): Fe2O362.7 parts MnCO329.5 parts Mg(OH)26.8 parts SrCO31.0 parts The ferrite raw materials were weighed to achieve the above composition ratio. Then, they were ground and mixed for 5 hours using a dry vibratory mill with 1 / 8-inch diameter stainless steel beads. • Process 2 (Calibration Process): The obtained pulverized material was processed into approximately 1 mm square pellets using a roller compactor. These pellets were then subjected to a vibrating sieve with a 3 mm mesh size to remove coarse powder, followed by a vibrating sieve with a 0.5 mm mesh size to remove fine powder. Finally, the pellets were calcined in a burner-type calcination furnace under a nitrogen atmosphere (oxygen concentration 0.01 vol%) at a temperature of 1000°C for 4 hours to produce calcined ferrite. The composition of the obtained calcined ferrite is as follows. (MnO)a(MgO)b(SrO)c(Fe2O3)d In the above formula, a=0.257, b=0.117, c=0.007, d=0.393 • Process 3 (Grinding process): After crushing the calcined ferrite to approximately 0.3 mm using a crusher, 30 parts water was added to 100 parts calcined ferrite using 1 / 8-inch diameter zirconia beads, and the mixture was ground in a wet ball mill for 1 hour. The resulting slurry was then ground in a wet ball mill using 1 / 16-inch diameter alumina beads for 4 hours to obtain a ferrite slurry (finely ground calcined ferrite). ·Process 4 (granulation process): To a ferrite slurry, 1.0 part of ammonium polycarboxylate was added as a dispersant and 2.0 parts of polyvinyl alcohol as a binder per 100 parts of calcined ferrite. The mixture was then granulated into spherical particles using a spray dryer (manufactured by Okawara Chemical Machinery). After adjusting the particle size of the resulting particles, they were heated in a rotary kiln at 650°C for 2 hours to remove the organic components of the dispersant and binder. • Process 5 (Baking Process): To control the firing atmosphere, the product was heated in an electric furnace under a nitrogen atmosphere (oxygen concentration 1.00 vol%) from room temperature to 1300°C in 2 hours, and then fired at 1150°C for 4 hours. After that, the temperature was cooled to 60°C over 4 hours, the atmosphere was changed from nitrogen to air, and the product was removed at a temperature of 40°C or lower. • Process 6 (sorting process): After crushing the aggregated particles, low-magnetic-force particles were cut by magnetic separation, and coarse particles were removed by sieving with a 250 μm mesh sieve to obtain magnetic core particles 1 with a 50% particle size (D50) of 37.0 μm based on volume distribution.

[0165] <Preparation of coating resin 1> Cyclohexyl methacrylate monomer 26.8% by mass Methyl methacrylate monomer 0.2% by mass Methyl methacrylate macromonomer 8.4% by mass (A macromonomer with a weight-average molecular weight of 5000, having a methacryloyl group at one end.) Toluene 31.3% by mass Methyl ethyl ketone 31.3% by mass Azobisisobutyronitrile 2.0% by mass Of the above materials, cyclohexyl methacrylate, methyl methacrylate, methyl methacrylate macromonomer, toluene, and methyl ethyl ketone were added to a four-necked separable flask equipped with a reflux condenser, thermometer, nitrogen inlet tube, and stirrer. Nitrogen gas was introduced to create a sufficient nitrogen atmosphere, and the mixture was heated to 80°C. Azobisisobutyronitrile was added, and polymerization was carried out under reflux for 5 hours. Hexane was injected into the resulting reaction product to precipitate the copolymer. After filtering off the precipitate, it was vacuum dried to obtain coating resin 1. 30 parts of the obtained coating resin 1 were dissolved in 40 parts of toluene and 30 parts of methyl ethyl ketone to obtain polymer solution 1 (solid content 30% by mass).

[0166] <Preparation of coating resin solution 1> Polymer solution 1 (resin solids concentration 30%) 33.3% by mass Toluene 66.4% by mass Carbon black (Regal330; manufactured by Cabot) 0.3% by mass (Primary particle size 25 nm, nitrogen adsorption specific surface area 94 m 2 / g, DBP oil absorption 75ml / 100g) The mixture was dispersed for 1 hour using zirconia beads with a diameter of 0.5 mm in a paint shaker. The resulting dispersion was filtered through a 5.0 μm membrane filter to obtain coating resin solution 1.

[0167] <Example of manufacturing magnetic carrier 1> (Resin coating process): In a vacuum-degassed kneader maintained at room temperature, coating resin solution 1 was added in a ratio of 2.5 parts resin component to 100 parts of packed core particles 1. After adding, the mixture was stirred at a rotation speed of 30 rpm for 15 minutes. After the solvent had evaporated to a certain level (80% by mass), the temperature was raised to 80°C while mixing under reduced pressure, and toluene was removed by distillation over 2 hours, followed by cooling. The obtained magnetic carriers were separated for low magnetic force by magnetic separation, passed through a sieve with an opening of 70 μm, and then classified in an air classifier to obtain magnetic carrier 1 with a volume distribution-based 50% particle size (D50) of 38.2 μm.

[0168] <Examples of manufacturing two-component developers and replenishment developers> Toners 1-18 and magnetic carrier 1 were mixed in a V-type mixer (V-10 model: Tokuju Seisakusho Co., Ltd.) for 0.5 seconds to achieve a toner density of 8.0% by mass. -1 The mixture was then mixed for a rotation time of 5 minutes to obtain the two-component developers 1 to 18 listed in Table 3.

[0169] Toners 1-18 and magnetic carrier 1 were mixed in a V-type mixer (V-10 model: Tokuju Seisakusho Co., Ltd.) for 0.5 seconds to achieve a toner density of 95.0% by mass. -1 The mixture was then mixed for a rotation time of 5 minutes to obtain the supplemental developers 1 to 18 listed in Table 3.

[0170] [Table 3]

[0171] [evaluation] The evaluation was conducted based on the following evaluation method. The evaluation results are shown in Table 4.

[0172] [Example 1] The following evaluations were performed using a two-component developer 1 and its replenishment developer 1.

[0173] A modified Canon full-color copier (product name: imageRUNNER ADVANCE C9075 PRO) was used as the image forming apparatus.

[0174] A two-component cyan toner developer was placed in each color developer unit, and a replenishment developer container containing cyan toner replenishment was set in each color unit. Images were then formed, and various evaluations were performed while durability tests were conducted.

[0175] The durability test involved outputting a total of 150,000 images across Steps 1 and 2, with the environment and image aspect ratio varied as follows.

[0176] Step 1 (from the 1st to the 100,000th image) Temperature 30℃ / Humidity 80%RH (hereinafter referred to as "H / H environment") FFH output chart with image ratio of 60% Step 2 (from the 100,001st to the 150,000th image) Temperature 23℃ / Humidity 5%RH (hereinafter referred to as "N / L environment") FFH output chart with image ratio of 3% Here, FFH is a value representing 256 gradations in hexadecimal, where 00H is the first gradation of 256 gradations (white area), and FFH is the 256th gradation of 256 gradations (solid area).

[0177] The other conditions are as follows: Paper: Laser beam printer paper CS-814 (product name) (81.4g / m²) 2 (Canon Marketing Japan Inc.) Image formation speed: Modified to output 80 A4-size, full-color images per minute. Development conditions: The development contrast can now be adjusted to any value, and the camera's automatic correction function has been disabled.

[0178] The voltage between peaks of the alternating electric field (Vpp) was modified so that it can be changed in 0.1kV increments from 0.7kV to 1.8kV at a frequency of 2.0kHz.

[0179] Each color unit was modified to output images in a single color.

[0180] The evaluation items are shown below.

[0181] (1) Ghost After Step 1 was completed, ten output charts were run, each containing a 5cm wide solid black vertical band in the center and solid white in the rest of the image. Then, one full-screen halftone image was output. The paper feeding direction is shown in Figure 2. On the halftone image, the image density in the area of ​​the drum where the solid black vertical band was fed and the image density in the area of ​​the drum where the solid white was fed were measured using a 500 series spectrophotometer (manufactured by X-Rite), and the difference was judged according to the following criteria. It was determined that the effect of the present invention was achieved at levels A to D. A: 0.00 or more, less than 0.02 B: 0.02 or higher, less than 0.03 C: 0.03 or higher, less than 0.04 D: 0.04 or higher, less than 0.06 E: 0.06 or higher

[0182] (2) Image density difference before and after durability of each step In Step 1 and Step 2, one FFH output chart (full A4 image) with 100% image ratio was printed at the beginning and end of each step. The image density was measured and judged using a 500 series spectrophotometer (manufactured by X-Rite).

[0183] The measurement sites are 0.5 cm from the leading edge of the image (where the image was formed first), and at three points: 5.0 cm, 15.0 cm, and 25.0 cm from the left edge of the image (where the image was formed first is at the top). At a position 7.0 cm from the front edge of the image, there are three points at 5.0 cm, 15.0 cm, and 25.0 cm from the left edge of the image. At a position 14.0 cm from the front of the image, there are three points at 5.0 cm, 15.0 cm, and 25.0 cm from the left edge of the image. At a position 20.0 cm from the front edge of the image, there are three points at 5.0 cm, 15.0 cm, and 25.0 cm from the left edge of the image. The total score was set at 12 points, and the average of these 12 points was calculated.

[0184] The evaluation was determined by comparing the average 12-point scores at the beginning and end of each step, according to the following criteria. The level at which the effects of the present invention were achieved was judged to be A to D. A: 0.00 or greater, less than 0.05 B: 0.05 or higher, less than 0.10 C: 0.10 or higher, less than 0.15 D: 0.15 or higher, less than 0.20 E: 0.20 or higher

[0185] (3) Image density difference between Step 1 and Step 2 At the end of Step 1 and at the end of Step 2, one FFH output chart (full A4 image) with an image ratio of 100% was printed. The reflectance density of the printed image was measured in the same way as the density difference described above, and the average value of 12 points was calculated.

[0186] The evaluation was determined by comparing the average 12-point scores of Step 1 and Step 2 according to the following criteria. It was determined that the level at which the effects of the present invention were achieved was A to D. A: 0.00 or greater, less than 0.05 B: 0.05 or higher, less than 0.10 C: 0.10 or higher, less than 0.15 D: 0.15 or higher, less than 0.20 E: 0.20 or higher

[0187] (4) Image Quality At the end of Step 2, a vertical line image with 1 dot and 1 space was output. The Blur value (a numerical value representing the degree of line blurring as defined by ISO 13660) was used as an evaluation index for image quality. Measurement was performed using a personal IAS (Image Analysis System) (manufactured by QEA). The obtained Blur values ​​were evaluated according to the following evaluation criteria. A value of D or higher was considered to indicate that the effects of the present invention were achieved. A: Blur value less than 35 μm B: Blur value between 35 μm and 38 μm C:Blur value between 38μm and 41μm D: Blur value between 41 μm and 44 μm E: Blur value of 44 μm or larger

[0188] (5) Overall Judgment The evaluation ranks of the above assessment were quantified (A=5, B=4, C=3, D=2, E=1), and the total value was determined according to the following criteria. It was determined that the level at which the effects of the present invention were achieved was A to C. A: 22 or more and 25 or less B: 18 or more and 21 or less C: 14 or more and 17 or less D: 10 or more and 13 or less E:9 or less

[0189] [Examples 2-11 and Comparative Examples 1-7] In Example 1, the evaluation was carried out in the same manner as in Example 1, except that the two-component developer and replenishment developer used for evaluation were changed to the two-component developer and replenishment developer listed in Table 3. The evaluation results are shown in Table 4.

[0190] [Table 4] [Explanation of symbols]

[0191] 1. Raw material quantitative supply means, 2. Compressed gas flow rate adjustment means, 3. Inlet pipe, 4. Protruding member, 5. Supply pipe, 6. Processing chamber, 7. Hot air supply means, 8. Cold air supply means, 9. Regulating means, 10. Recovery means, 11. Hot air supply means outlet, 12. Distribution member, 13. Swirling member, 14. Powder particle supply port

Claims

1. A toner comprising toner particles containing a binder resin, and a toner having silica particles on the surface of the toner particles, The silica particles are contained in an amount of 0.40 parts by mass or more and 3.50 parts by mass or less per 100 parts by mass of toner particles. The adhesion rate of the silica particles to the toner particles is 90% or more. The specific gravity of the silica particles is 1.7 g / cm³. 3 That's all. The percentage of carbon atoms in the silica particles, as determined by X-ray photoelectron spectroscopy (ESCA), is 18 atoms or more. The toner is characterized in that the silica particles are silica particles treated with dimethyldimethoxysilane to create a hydrophobized silica particle.

2. The toner according to claim 1, wherein the number-average particle size of the silica particles is 40 nm or more and 200 nm or less.

3. The toner according to claim 1 or 2, wherein the silica particles are hydrophobized silica particles that have been treated with dimethyldimethoxysilane and then with trimethylsilanol.

4. The toner according to claim 1 or 2, wherein the silica-derived peak ratio, determined by peak separation of the Si2P spectrum measured by an X-ray photoelectron spectrometer (ESCA) of the silica particles, is 40% or less of the total Si.

5. A method for manufacturing toner, comprising a mixing step of mixing toner particles containing a binder resin with silica particles to obtain a toner particle mixture, and a heat treatment step of heat treating the toner particle mixture with hot air, The toner contains 0.40 parts by mass or more and 3.50 parts by mass or less of the silica particles per 100 parts by mass of the toner particles. The adhesion rate of the silica particles to the toner particles is 90% or more. The specific gravity of the silica particles is 1.7 g / cm³. 3 That's all. The percentage of carbon atoms in the silica particles, as determined by X-ray photoelectron spectroscopy (ESCA), is 18 atoms or more. A method for producing toner, characterized in that the silica particles are treated with dimethyldimethoxysilane.

6. The method for producing toner according to claim 5, wherein the silica particles are treated with dimethyldimethoxysilane in an amount of 30 to 80 parts by mass per 100 parts by mass of silica raw material.

7. A method for producing toner according to claim 5 or 6, wherein the silica particles are treated with dimethyldimethoxysilane and then subjected to trimethylsilylation treatment with trimethylsilanol.

8. A two-component developer having toner and a magnetic carrier, A two-component developer characterized in that the toner is the toner described in claim 1.

Images