Toner and method for manufacturing toner

Abstract

To provide a toner that can achieve both transfer properties and cleaning properties at a high level even when accelerated and extended in service life.SOLUTION: A toner has toner particles containing a binder resin and inorganic oxide particles. The inorganic oxide particle is a particle of an oxide including at least one element selected from the group consisting of Si, Mg, Al, Ti, and Sr. In cross-sectional observation of the toner by a transmission electron microscope, when the area of the inorganic oxide particle is defined as Sm, and the cross-sectional area of the toner as St, Sm / St is 4.0% or more. In the cross-sectional observation, an area is divided into four by the major axis of the toner and the perpendicular bisector of the major axis, and in each area obtained through the division, the standard deviation of the area Sm of the inorganic oxide particles is 0.40 or more. The average circularity of the toner is 0.950 or more.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to a toner used in recording methods such as electrophotography, and a method for manufacturing the toner. [Background technology]

[0002] In recent years, electrophotographic devices such as desktop printers have shifted from environments where multiple people share one device to environments where each person has their own device, creating a demand for both higher image quality and miniaturization. One effective way to miniaturize process cartridges is to adopt a cleanerless system. Most printers employ a cleaner system, in which toner remaining on the electrostatic latent image carrier during the transfer process (hereinafter referred to as transfer residue toner) is scraped off the carrier by a cleaning blade and collected in a waste toner box. On the other hand, cleanerless systems, lacking cleaning blades and waste toner boxes, can significantly contribute to miniaturizing the main unit. On the other hand, with the global spread of printers, the types of paper used have also diversified. In particular, when using paper with low strength or paper containing a large amount of filler, a large amount of so-called "paper dust" tends to be generated during printing. This paper dust tends to cause various problems in cleanerless systems. In particular, in transfer methods where the image is transferred directly from the photoreceptor to the paper, the photoreceptor and the paper come into direct contact. In this case, paper dust is more likely to adhere to the photoreceptor. In a cleaner system, the paper dust that adheres to the photoreceptor is collected along with the remaining toner by a cleaning blade. However, in a cleanerless system, the paper dust is not collected along with the remaining toner and returns to the charging and developing processes, making it easier for various image defects to occur. To suppress the adhesion of paper dust to the surface of the photoreceptor as described above, reducing the transfer current applied during the transfer process is effective. However, reducing the transfer current tends to decrease the transfer efficiency. To improve transfer efficiency, Patent Document 1 describes an attempt to treat pulverized toner containing silica aggregates by heating and spheroidizing it. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2007-140368 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] However, it was found that the technology described in Patent Document 1 is insufficient to achieve a high level of both transferability and cleaning performance when further increasing speed and extending lifespan. In particular, it was found that there are challenges in achieving both transferability and cleaning performance in cleanerless systems. This invention provides a toner that solves the above problems. Specifically, it provides a toner that achieves a high level of balance between transferability and cleaning performance when speed and lifespan are increased. We provide toner that makes this possible. [Means for solving the problem]

[0005] As a result of diligent research, the inventors of this invention discovered that the above problems can be solved with the following toner, leading to the present invention. In other words, the present invention relates to a toner having toner particles containing a binder resin and inorganic oxide particles, The inorganic oxide particles are oxide particles containing at least one element selected from the group consisting of Si, Mg, Al, Ti, and Sr. In cross-sectional observation of the toner using a transmission electron microscope, when the area of ​​the inorganic oxide particles is Sm and the cross-sectional area of ​​the toner is St, the Sm / St ratio is 4.0% or more. In the cross-sectional observation, the standard deviation (μm) of the area Sm of the inorganic oxide particles in each of the four regions divided by the major axis of the toner and the perpendicular bisector of the major axis is measured.2 ) is 0.40 or higher, The average circularity of the toner is 0.950 or higher. the law of nature, The weight-average particle size (D4) of the toner is 3.0 to 10.0 μm. This relates to a toner characterized by [something]. Furthermore, the present invention relates to a method for producing toner having toner particles containing a binder resin and inorganic oxide particles, The manufacturing method includes a step of obtaining the toner particles, The process for obtaining the toner particles includes the steps of obtaining toner particles before surface treatment with hot air, and surface treating the toner particles before surface treatment with hot air with hot air. The step of obtaining toner particles before surface treatment with hot air includes a step of melting and kneading the binder resin and the inorganic oxide particles. The inorganic oxide particles are an oxide containing at least one element selected from the group consisting of Si, Mg, Al, Ti, and Sr. In cross-sectional observation of the toner using a transmission electron microscope, when the area of ​​the inorganic oxide particles is Sm and the cross-sectional area of ​​the toner is St, the ratio Sm / St is 4.0% or more. In the cross-sectional observation, the standard deviation (μm) of the area Sm of the inorganic oxide particles in each of the four regions divided by the major axis of the toner and the perpendicular bisector of the major axis is measured. 2 ) is 0.40 or higher, The average circularity of the toner is 0.950 or higher. the law of nature, The weight-average particle size (D4) of the toner is 3.0 to 10.0 μm. ru This invention relates to a method for manufacturing toner characterized by the following features. [Effects of the Invention]

[0006] According to the present invention, it is possible to achieve a high level of balance between transfer performance and cleaning performance when the speed and lifespan are increased. [Brief explanation of the drawing]

[0007] [Figure 1] This is a diagram illustrating the pointed part. [Figure 2]It is a cross-sectional view of a surface treatment apparatus using hot air. [Figure 3] It is an evaluation image of cleaning property. [Figure 4] It is a schematic cross-sectional view of a process cartridge.

Mode for Carrying Out the Invention

[0008] Hereinafter, the present invention will be described in detail, but it is not limited thereto.

[0009] 〔Features of the Present Invention〕 As a result of intensive studies, the present inventors have found that the above problems can be solved by the following toner, and have arrived at the present invention.

[0010] That is, the present invention is a toner having toner particles containing a binder resin and inorganic oxide particles, the inorganic oxide particles are particles of an oxide containing at least one element selected from the group consisting of Si, Mg, Al, Ti, and Sr, in the cross-sectional observation of the toner by a transmission electron microscope, when the area of the inorganic oxide particles is Sm and the cross-sectional area of the toner is St, Sm / St is 4.0% or more, and in the cross-sectional observation, in the region divided into four by the major axis of the toner and the perpendicular bisector of the major axis, the standard deviation of the area Sm of the inorganic oxide particles occupying each region is 0.40 or more, the average circularity of the toner is 0.950 or more.

[0011] Regarding the reason why the effects of the present invention can be obtained by satisfying the above conditions, the present inventors consider as follows.

[0012] As a means for improving the transferability of conventional toner, increasing the circularity of the toner and reducing the adhesion have been performed. On the other hand, when the circularity increases, the rolling property improves, so that the problem has been that the cleaning property deteriorates.

[0013] In contrast, the present invention believes that the above problems can be solved by the following mechanism. By incorporating inorganic oxide particles containing at least one element selected from the group consisting of Si, Mg, Al, Ti, and Sr into a highly circular toner, a difference in specific gravity is created between the organic and inorganic components inside the toner. In cross-sectional observation of the toner using a transmission electron microscope, when the area of ​​the inorganic oxide particles is Sm and the cross-sectional area of ​​the toner is St, if Sm / St is 4.0% or more, and in the cross-sectional observation, in a region divided into four parts by the major axis of the toner and the perpendicular bisector of the major axis, the standard deviation of the area Sm of the inorganic oxide particles in each region is 0.40 or more, an imbalance in the difference in specific gravity occurs between the organic and inorganic components inside the toner, causing the center of gravity of the toner to be off-center. As a result, it is believed that rolling can be suppressed even in highly circular toners, and cleaning performance can be improved.

[0014] The inorganic oxide particles are oxide particles containing at least one element selected from the group consisting of Si, Mg, Al, Ti, and Sr, which do not impair electrophotographic properties, thereby creating a specific gravity difference with the organic components of the toner. Silica particles are particularly preferred in terms of improving durability, and the effects of the present invention are easily obtained even in the latter half of the lifespan. Furthermore, an Sm / St ratio of 4.0% or more ensures that the toner contains a sufficient volume of inorganic oxide particles to create a specific gravity difference. If it is less than 4.0%, the specific gravity difference inside the toner is small and rolling cannot be suppressed, resulting in poor cleaning performance. The Sm / St ratio can be controlled by the amount and particle size of the inorganic oxide particles added.

[0015] Furthermore, if the standard deviation of Sm is less than 0.40, the bias in specific gravity difference becomes small, making it impossible to suppress the rolling of the toner, thus worsening cleaning performance. The standard deviation of Sm is preferably 0.50 or higher. The standard deviation of Sm can be controlled by the amount, particle size, and shape of the inorganic oxide particles added.

[0016] Furthermore, the average circularity of the toner of the present invention is 0.950 or higher. If it is less than 0.950, the effect of reducing the adhesion strength of the toner becomes smaller and the transferability deteriorates. The average circularity is preferably 0.960 or higher. The average circularity can be controlled by the toner manufacturing method, for example, by the conditions of the hot air surface treatment process described later in the case of the grinding method.

[0017] Furthermore, in cross-sectional observation using a transmission electron microscope, the major axis of the inorganic oxide particles in the toner of the present invention is preferably 400 to 3000 nm. A major axis of 400 nm or more makes it easier to create a bias in the specific gravity difference between organic and inorganic components within the toner, thus making it easier to obtain the effects of the present invention. Especially when obtaining toner by a pulverization method, a major axis of 400 nm or more of the inorganic oxide particles makes it easier for the inorganic oxide particles to become the pulverization interface, thus making it easier to shift the center of gravity of the toner and obtain the effects of the present invention. A major axis of 3000 nm or less improves durability, and the effects of the present invention are easily obtained even in the latter half of the lifespan. More preferably, the major axis is 750 to 3000 nm. The major axis of the inorganic oxide particles can be controlled by the rotation speed of the pulverizer, the screen size, and the number of passes when manufacturing the inorganic oxide particles, as described later. Alternatively, it can be controlled by classifying the inorganic oxide particles.

[0018] Furthermore, in cross-sectional observation using a transmission electron microscope, it is preferable that the inorganic oxide particles of the toner of the present invention have pointed portions, as described below. The pointed portions of the inorganic oxide particles refer to the parts of the toner where the angle shown in Figure 1 is 90 degrees or less, as observed in cross-sectional observation of the toner. A specific method for determining whether or not inorganic oxide particles have pointed portions will be described below. Having pointed portions makes it easier for the inorganic oxide particles to become the pulverization interface, especially when obtaining toner by a pulverization method, as this makes it easier for the center of gravity of the toner to be shifted and the effects of the present invention to be obtained. The presence or absence of pointed portions of inorganic oxide particles can be controlled by the rotation speed of the pulverizer and the slit width when manufacturing the inorganic oxide particles.

[0019] Furthermore, it is preferable that the shape factor SF-1 of the inorganic oxide particles observed by a transmission electron microscope is 140 or higher. When SF-1 is 140 or higher, especially when obtaining toner by a pulverization method, the inorganic oxide particles tend to become pulverization interfaces, which makes it easier to shift the center of gravity of the toner and obtain the effects of the present invention. The shape factor SF1 of the inorganic oxide particles can be controlled by the rotation speed of the pulverizer, the screen size, and the number of passes when manufacturing the inorganic oxide particles.

[0020] Furthermore, the toner of the present invention preferably contains an external additive, and the coverage rate of the external additive is preferably 75% or more. A coverage rate of 75% or more of the external additive makes it easier to obtain the effects of the present invention even in the later stages of its lifespan. The coverage rate of the external additive can be controlled by the type and amount of the external additive added.

[0021] Embodiments of the present invention will be described in detail below.

[0022] [Inorganic oxide particles] The inorganic oxide particles of the present invention are not particularly restricted in terms of their manufacturing method, and those manufactured by known methods can be used. In particular, methods for manufacturing silica particles include a gas-phase method in which silicon compounds such as metallic silicon, silicon halides, and silane compounds are reacted in the gas phase, and a wet method in which silane compounds such as alkoxysilanes are hydrolyzed and condensed. The silica particles that can be used in the toner of the present invention can be manufactured using any method without restriction. Since the silica particles suitable for the present invention are relatively large, ranging from 400 to 3000 nm, a gas-phase oxidation method in which the powder raw material is directly oxidized with a chemical flame consisting of oxygen and hydrogen is particularly preferred. The gas-phase oxidation method makes it possible to instantaneously raise the temperature inside the reaction vessel above the melting point of the inorganic fine powder, and is a preferred method for obtaining large silica particles.

[0023] Silica particles can be produced, for example, by manufacturing silica particles of about 3000-5000 nm using the gas-phase oxidation method described above, and then grinding them using a known method to obtain silica particles with pointed ends. As for the grinder, using a device with high grinding capacity, such as a pulverizer or jet mill, makes it easier to control the shape and particle size. The shape and particle size can be controlled by changing the rotation speed of the pulverizer, the slit width, etc. In addition, the particle size distribution can be adjusted as appropriate using a known classifier.

[0024] In particular, to form pointed portions in silica particles, it is preferable to have a grinding step in the production of silica particles. According to the inventors' studies, conventional production methods such as those for fumed silica and sol-gel silica make it difficult to form pointed portions. Furthermore, the particle size distribution can be adjusted using known classification equipment as appropriate.

[0025] Similarly, the manufacturing method for Mg, Al, Ti, and Sr oxides can be selected without restriction. For example, oxides can be produced by refining or synthesis using minerals as raw materials, and then adjusted to a size and shape suitable for the present invention by crushing or classifying as needed.

[0026] 〔toner〕 The toner contains a binder resin. The binder resin is not particularly limited, and known materials such as vinyl resins and polyester resins can be used.

[0027] Specifically, styrene copolymers such as polystyrene, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-octyl methacrylate copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-maleic acid copolymer, and styrene-maleic acid ester copolymer, as well as polyacrylic acid esters, polymethacrylic acid esters, and polyvinyl acetate can be used, and these can be used individually or in combination. The binder resin is preferably an amorphous resin. Styrene copolymers and polyester resins are preferred as binder resins in terms of developing characteristics and fixing properties. Amorphous polyester resins are preferred for polyester resins. The binder resin more preferably contains styreneacrylic resin. Styreneacrylic resin improves durability, and the effects of the present invention are easily obtained even in the later stages of durability, even with extended lifespan.

[0028] Furthermore, it is preferable that the binder resin has at least two peaks or shoulders in the molecular weight distribution of tetrahydrofuran-soluble components, with a weight-average molecular weight Mw between 3,000 and 2,000,000. Having at least two peaks or shoulders between 3,000 and 2,000,000 improves durability, and the effects of the present invention are more easily obtained even in the later stages of durability, resulting in a longer lifespan.

[0029] In the present invention, it is preferable to include a mold release agent as one of the materials constituting the toner base. In particular, using an ester wax having a melting point of 60°C to 90°C makes it easier to obtain a plasticizing effect due to its excellent compatibility with the binder resin.

[0030] Examples of ester waxes used in the present invention include waxes mainly composed of fatty acid esters such as carnauba wax and montanate ester wax; and fatty acid esters from which some or all of the acid component has been deoxidized, such as deoxidized carnauba wax; methyl ester compounds having a hydroxyl group obtained by hydrogenation of vegetable oils and fats; saturated fatty acid monoesters such as stearyl stearate and behenyl behenate; diesterified products of saturated aliphatic dicarboxylic acids and saturated aliphatic alcohols such as dibehenyl sebacate, distearyl dodecanediol, and distearyl octadecanediol; and diesterified products of saturated aliphatic diols and saturated aliphatic monocarboxylic acids such as nonanediol dibehenate and dodecanediol distearate.

[0031] Furthermore, among these waxes, it is preferable that they contain a bifunctional ester wax (diester) having two ester bonds in its molecular structure.

[0032] Bifunctional ester waxes are ester compounds of a dihydric alcohol and an aliphatic monocarboxylic acid, or ester compounds of a dihydric carboxylic acid and an aliphatic monoalcohol.

[0033] Specific examples of the above-mentioned aliphatic monocarboxylic acids include myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, montanic acid, melissic acid, oleic acid, vaccenic acid, linoleic acid, and linolenic acid.

[0034] Specific examples of the above-mentioned aliphatic monoalcohols include myristyl alcohol, cetanol, stearyl alcohol, arachidyl alcohol, behenyl alcohol, tetracosanol, hexacosanol, octacosanol, and triacontanol.

[0035] Specific examples of divalent carboxylic acids include butanediic acid (succinic acid), pentanediic acid (glutaric acid), hexanediic acid (adipic acid), heptanediic acid (pimelic acid), octanedioic acid (suberic acid), nonanedioic acid (azelaic acid), decanediic acid (sebacic acid), dodecanediic acid, tridecanediic acid, tetradecanediic acid, hexadecanedioic acid, octadecanediic acid, eicosanedioic acid, phthalic acid, isophthalic acid, and terephthalic acid.

[0036] Specific examples of dihydric alcohols include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,10-decanediol, 1,12-dodecanediol, 1,14-tetradecanediol, 1,16-hexadecanediol, 1,18-octadecanediol, 1,20-eicosanediol, 1,30-triacontanediol, diethylene glycol, dipropylene glycol, 2,2,4-trimethyl-1,3-pentanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, spiroglycol, 1,4-phenylene glycol, bisphenol A, and hydrogenated bisphenol A.

[0037] Other usable release agents include paraffin wax, microcrystalline wax, petroleum-based waxes such as petrolatum and their derivatives, montan wax and its derivatives, hydrocarbon waxes and their derivatives produced by the Fischer-Tropsch process, polyolefin waxes such as polyethylene and polypropylene and their derivatives, natural waxes such as carnauba wax and candelilla wax and their derivatives, higher aliphatic alcohols, fatty acids such as stearic acid and palmitic acid, or compounds thereof. The release agent content is preferably 5.0 to 20.0 parts by mass per 100.0 parts by mass of the binder resin or polymerizable monomer.

[0038] In the present invention, the inclusion of a colorant in the toner particles is not particularly limited, and the known colorants shown below can be used.

[0039] Yellow pigments used include condensed azo compounds such as yellow iron oxide, Navel Yellow, Naphthol Yellow S, Hansa Yellow G, Hansa Yellow 10G, benzidine Yellow G, benzidine Yellow GR, quinoline yellow lake, permanent yellow NCG, and tartrazine lake, as well as isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds. Specifically, the following can be mentioned.

[0040] CI Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 109, 110, 111, 128, 129, 147, 155, 168, 180.

[0041] Examples of red pigments include condensed azo compounds such as red iron oxide, permanent red 4R, lysol red, pyrazolone red, watching red calcium salt, lake red C, laked D, brilliant carmine 6B, brilliant carmine 3B, eosin lake, rhodamine lake B, and alizarin lake, as well as diketopyrrolopyrrole compounds, anthraquinone, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. Specifically, the following can be mentioned.

[0042] CI Pigment Red 2, 3, 5, 6, 7, 23, 48:2, 48:3, 48:4, 57:1, 81:1, 122, 144, 146, 166, 169, 177, 184, 185, 202, 206, 220, 221, 254.

[0043] Examples of blue pigments include alkali blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partial chloride, first sky blue, copper phthalocyanine compounds and their derivatives such as induthlene blue BG, anthraquinone compounds, and basic dye lake compounds. Specifically, the following can be mentioned.

[0044] CI Pigment Blue 1, 7, 15, 15:1, 15:2, 15:3, 15:4, 60, 62, 66.

[0045] Examples of black pigments include carbon black and aniline black. These colorants can be used individually, in combination, or even in solid solution form.

[0046] Furthermore, the colorant content is preferably 3.0 to 15.0 parts by mass per 100.0 parts by mass of the binder resin or polymerizable monomer.

[0047] In the present invention, the toner base may contain a charge control agent. Known charge control agents can be used. A charge control agent that has a fast charging speed and can stably maintain a constant amount of charge is particularly preferred.

[0048] Examples of charge control agents that control the charge properties of toner particles according to the load include the following:

[0049] Examples of organometallic compounds and chelates include monoazo metal compounds, acetylacetone metal compounds, aromatic oxycarboxylic acids, aromatic dicarboxylic acids, and metal compounds of oxycarboxylic and dicarboxylic acid systems. Other examples include aromatic oxycarboxylic acids, aromatic mono and polycarboxylic acids and their metal salts, anhydrides or esters, and phenol derivatives such as bisphenol. Furthermore, examples include urea derivatives, metal-containing salicylic acid compounds, metal-containing naphthoic acid compounds, boron compounds, quaternary ammonium salts, and calixarenes.

[0050] On the other hand, the following are examples of charge control agents that control the positive charge of toner particles: nigrosine and nigrosine-modified products such as fatty acid metal salts; guanidine compounds; imidazole compounds; onium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, and their analogues such as phosphonium salts, and their lake pigments; triphenylmethane dyes and their lake pigments (lake agents include phosphotungstic acid, phosphomolybdic acid, phosphotungstenmolybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide, ferrocyanide, etc.); metal salts of higher fatty acids; resin-based charge control agents.

[0051] These charge control agents can be included individually or in combination of two or more types. Preferably, the amount of these charge control agents added is 0.01 to 10.00 parts by mass per 100.00 parts by mass of the binder resin or polymerizable monomer.

[0052] The toner may contain toner particles and external additives on the surface of the toner particles. Examples of external additives include those that are well known.

[0053] Examples of external additives include metal oxide nanoparticles (inorganic nanoparticles) such as silica nanoparticles, alumina nanoparticles, titania nanoparticles, zinc oxide nanoparticles, strontium titanate nanoparticles, cerium oxide nanoparticles, and calcium carbonate nanoparticles.

[0054] Toner may also contain small amounts of other additives, such as lubricating powders like fluororesin powder, zinc stearate powder, and polyvinylidene fluoride powder, within limits that do not cause substantial adverse effects; abrasives like cerium oxide powder, silicon carbide powder, and strontium titanate powder; fluidity enhancers like titanium oxide powder and aluminum oxide powder; anticaking agents; or reverse polarity organic and inorganic microparticles as developability enhancers. These additives may also be used after their surfaces have been hydrophobized.

[0055] The weight-average particle size (D4) of the toner is preferably 3.0 to 12.0 μm, and more preferably 4.0 to 10.0 μm. When the weight-average particle size (D4) is within the above range, good fluidity is obtained, and the latent image can be developed faithfully.

[0056] [Toner manufacturing method] The toner manufacturing method of the present invention can be conventionally known methods without any particular limitations. Specifically, examples include suspension polymerization, dissolution suspension, emulsification agglutination, spray drying, and pulverization. Among these, pulverization is preferred, which includes a step of melting and kneading a binder resin and inorganic oxide particles, and a step of surface treating the toner particles with hot air. In pulverization, inorganic oxide particles tend to become the pulverization interface in the pulverization step, and an uneven distribution of inorganic oxide particles within the toner particles is easily created, making it easier to obtain the effects of the present invention.

[0057] The following are specific examples of pulverization methods for producing toner through a melting and kneading process and a pulverization process, but are not limited to these.

[0058] For example, binder resin, inorganic oxide particles, and optionally colorants, release agents, charge control agents, and other additives are thoroughly mixed using a mixer such as a Henschel mixer or ball mill (mixing step). The resulting mixture is then melt-kneaded using a thermal kneader such as a twin-screw extruder, heated roll, kneader, or extruder (melt-kneading step).

[0059] After the obtained molten mixture is cooled and solidified, it is crushed using a pulverizer (crushing step) and then classified using a classifier (classification step) to obtain toner particles. The toner particles may be used as toner as is. If necessary, the toner particles and external additives may be mixed using a mixer such as a Henschel mixer to obtain toner.

[0060] Examples of mixing machines include: FM mixer (Nippon Coke Industries Co., Ltd.); Super mixer (Kawata Co., Ltd.); Ribocone (Okawara Seisakusho Co., Ltd.); Nauter mixer, Turbulizer, Cyclomix (Hosokawa Micron Co., Ltd.); Spiral pin mixer (Taiheiyo Kiko Co., Ltd.); Redigge mixer (Matsubo Co., Ltd.).

[0061] Examples of heat kneaders include: KRC kneader (manufactured by Kurimoto Iron Works); Buss-Co kneader (manufactured by Buss); TEM type extruder (manufactured by Toshiba Machine Co.); TEX twin-screw kneader (manufactured by Japan Steel Works); PCM kneader (manufactured by Ikegai Iron Works); three-roll mill, mixing roll mill, kneader (manufactured by Inoue Seisakusho); Nidex (manufactured by Mitsui Mining Co.); MS type pressure kneader, Nidaruder (manufactured by Moriyama Seisakusho); Banbury mixer (manufactured by Kobe Steel).

[0062] Examples of crushing machines include: counter jet mill, micron jet, inomizer (manufactured by Hosokawa Micron Co., Ltd.); IDS type mill, PJM jet crusher (manufactured by Nippon Pneumatic Mfg. Co., Ltd.); cross jet mill (manufactured by Kurimoto Iron Works Co., Ltd.); Ulmax (manufactured by Nisso Engineering Co., Ltd.); SK Jet-O-Mill (manufactured by Seishin Enterprise Co., Ltd.); Cryptron (manufactured by Kawasaki Heavy Industries, Ltd.); Turbo Mill (manufactured by Turbo Industries Co., Ltd.); and Super Rotor (manufactured by Nisshin Engineering Co., Ltd.).

[0063] Examples of classifiers include: Classil, Micron Classifier, Spedick Classifier (manufactured by Seishin Corporation); Turbo Classifier (manufactured by Nisshin Engineering Co., Ltd.); Micron Separator, Turboplex (ATP), TSP Separator (manufactured by Hosokawa Micron Corporation); Elbow Jet (manufactured by Nippon Steel Mining Co., Ltd.), Dispersion Separator (manufactured by Nippon Pneumatic Mfg. Co., Ltd.); and YM Microcut (manufactured by Yaskawa Trading Co., Ltd.).

[0064] Additionally, the following sieving devices may be used to separate coarse particles: Ultrasonic (manufactured by Koei Sangyo Co., Ltd.); Resona Sieve, Gyro Shifter (manufactured by Tokuju Kogyo Co., Ltd.); Vibrasonic System (manufactured by Dalton Co., Ltd.); Soniclean (manufactured by Shinto Kogyo Co., Ltd.); Turbo Screener (manufactured by Turbo Kogyo Co., Ltd.); Micro Shifter (manufactured by Makino Sangyo Co., Ltd.); Circular Vibrating Sieve.

[0065] An adhesion step and a surface treatment step using hot air may be applied to the surface of the toner matrix particles obtained in this manner, in which inorganic particles are attached. The method of attaching inorganic particles to the surface of the toner matrix particles in the adhesion step is not particularly limited, and predetermined amounts of toner matrix particles and inorganic particles are weighed, blended, and mixed. Examples of mixing devices include double-con mixers, V-type mixers, drum-type mixers, super mixers, Henschel mixers, and Nauter mixers, each of which is preferably used.

[0066] In terms of mixing conditions, a higher rotation speed of the mixing blades and a longer mixing time are preferable because they make it easier to uniformly adhere boron nitride particles to the surface of the toner matrix particles. However, if the rotation speed of the mixing blades is too high or the mixing time is too long, the frictional heat between the toner and the mixing blades will increase, causing the toner to heat up and fuse. Therefore, it is preferable to actively cool the mixing machine by providing a water-cooling jacket on the mixing blades or the mixing machine itself.

[0067] The rotation speed of the mixing blades and the mixing time should preferably be adjusted within a range that keeps the temperature inside the mixer below 45°C. Specifically, the maximum peripheral speed of the mixing blades should preferably be between 10.0 and 150.0 m / sec, and the mixing time should preferably be adjusted within a range of 0.5 to 60 minutes.

[0068] Furthermore, the adhesion process may be carried out in one stage or in two or more stages, and the mixing equipment, mixing conditions, and toner matrix particle composition used in each stage may be the same or different.

[0069] Next, as an apparatus used for surface treatment of toner matrix particles, one can be used that has means for melting the surface of the toner particles before treatment using hot air, and means for cooling the toner particles treated with hot air with cold air.

[0070] Examples of such devices include the Meteor Rainbow MR Type (manufactured by Nippon Pneumatic Mfg. Co., Ltd.).

[0071] One embodiment of a surface treatment method using hot air will be explained with reference to Figure 2, but is not limited thereto. Figure 2 is an example of a cross-sectional view of a surface treatment apparatus used in the present invention. Specifically, the surface treatment method involves using a material in which organosilicon polymer particles have been attached to the surface of toner matrix particles in advance as the raw material, and supplying the raw material to the surface treatment apparatus.

[0072] Then, the toner particles 114, which are supplied from the toner particle supply port 100 and are not yet surface-treated, are accelerated by the injection air sprayed from the high-pressure air supply nozzle 115 and head towards the airflow injection member 102 located below them.

[0073] Diffusion air is injected from the airflow injection member 102, and this diffusion air causes the toner particles 114 to diffuse outwards. At this time, the diffusion state of the toner particles can be controlled by adjusting the flow rate of the injection air and the flow rate of the diffusion air.

[0074] Furthermore, to prevent toner particles from fusing together, cooling jackets 106 are provided on the outer circumference of the toner particle supply port 100, the outer circumference of the surface treatment device, and the outer circumference of the transfer piping 116.

[0075] Furthermore, it is preferable to pass cooling water (preferably an antifreeze such as ethylene glycol) through the cooling jacket.

[0076] Meanwhile, the toner particles diffused by the diffused air have their surfaces treated by the hot air supplied from the hot air supply port 101.

[0077] In this case, the discharge temperature of the hot air is above the softening point of the toner, preferably between 120°C and 300°C, and more preferably between 150°C and 250°C.

[0078] When the temperature of the hot air exceeds the softening point of the toner, the binder resin dissolves, and as a result, the organosilicon polymer particles adhere to the toner matrix particles.

[0079] If the hot air discharge temperature exceeds 300°C, the toner particles may melt too much, making them more prone to coalescence during the manufacturing process. This can lead to the toner particles becoming coarser or the toner particles fusing excessively to the inner walls of the equipment.

[0080] Toner particles whose surfaces have been treated with hot air are cooled by cold air supplied from a cold air supply port 103 located on the outer periphery of the upper part of the device. At this time, it is preferable to introduce cold air from a second cold air supply port 104 located on the side of the main body of the device in order to control the temperature distribution inside the device and control the surface condition of the toner particles. The outlet of the second cold air supply port 104 can be a slit shape, louver shape, perforated plate shape, mesh shape, etc., and the direction of introduction can be selected according to the purpose, either horizontally towards the center or along the wall surface of the device.

[0081] In this case, it is preferable to adjust the airflow rates of both hot and cold air to be low in order to allow for a longer crosslinking reaction time.

[0082] Furthermore, it is preferable that the above-mentioned cool air is dehumidified air, as this allows water molecules generated during the crosslinking reaction to be discharged from the system. Specifically, the absolute moisture content of the cool air should be 5 g / m³. 3 The following is preferable. More preferably, 3 g / m 3 The following applies:

[0083] The cooled toner particles are then sucked up by a blower and collected by a cyclone or similar device through the transfer piping 116.

[0084] [Measurement methods for each physical property] Next, we will describe the measurement methods for each physical property.

[0085] <Compositional analysis of inorganic oxide particles> The inorganic oxide particles contained in the toner particles of this invention refer to the inorganic oxide particles contained in the toner mother particles before the adhesion process, in which inorganic oxide particles are attached to the surface of the toner mother particles before the hot air surface treatment process, and before the external addition process. Based on cross-sectional images of the toner particles observed with a transmission electron microscope (TEM), particles where 80% or more of the area is located more than 100 nm inward from the outer edge of the toner were defined as inorganic oxide particles contained in the toner particles. Furthermore, the composition of the inorganic oxide particles was determined by confirming that the particles consist of at least one element selected from Si, Mg, Al, Ti, and Sr, and oxygen, using an energy-dispersive X-ray spectrometer (EDX).

[0086] Images of toner particle cross-sections obtained by transmission electron microscopy (TEM) are prepared as follows.

[0087] Using an osmium plasma coater (filgen, OPC80T), an Os film (5nm) and a naphthalene film (20nm) are applied to the toner as protective films. After embedding in photocurable resin D800 (JEOL), toner particle cross-sections with a film thickness of 60nm (or 70nm) are prepared using an ultrasonic ultramicrotome (Leica, UC7) at a cutting speed of 1mm / s.

[0088] The obtained cross-sections will be observed using the STEM function of a TEM (JEOL, JEM2800). The STEM probe size will be 1 nm, and the image size will be 1024 × 1024 pixels. Of the toner particle cross-sections, those with a diameter of 0.9 to 1.1 times the weight-average particle size will be selected.

[0089] <Measurement of major axis, area Sm, shape factor SF-1, and toner area St of inorganic oxide particles> The major axis of inorganic oxide particles is determined from the obtained image using the image processing software "Image-Pro Plus ver.4.0 (Media Cybernetics)". In calculating the major axis, the cross-sections of 100 toner particles are observed, and the average value of these cross-sections is taken as the major axis of the inorganic oxide particles. Similarly, the cross-sections of 100 toner particles are observed, and the cross-sectional area of ​​the toner and the area of ​​the inorganic oxide particles are determined, with their average values ​​taken as the cross-sectional area of ​​the toner (St) and the area of ​​the inorganic oxide particles (Sm), respectively.

[0090] Furthermore, the shape coefficient SF-1 of the inorganic oxide particles is determined from the major axis and area Sm of the inorganic oxide particles calculated above using the following formula. SF-1 = (major axis of inorganic oxide particles) 2 Area of ​​inorganic oxide particles: Sm × π / 4 × 100

[0091] SF1 was calculated from cross-sectional observations of 100 toner particles, and the average value was used as the shape coefficient SF1 for inorganic oxide particles.

[0092] <How to determine the standard deviation of the area Sm of inorganic oxide particles> In the cross-sectional images of toner particles observed with the above-mentioned transmission electron microscope (TEM), the standard deviation of the area Sm of inorganic oxide particles in each of the four regions divided by the major axis of the toner and the perpendicular bisector of the major axis was determined.

[0093] <Measurement of average circularity of toner The 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.

[0094] 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.

[0095] A strobe light is shone onto the sample passing through the flat-sheath flow cell at 1 / 60 second intervals, making it possible to capture still images of the flowing particles. Furthermore, because the flow is flat, 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 contours of each particle image, and the projected area S and perimeter L of the particle image are measured.

[0096] 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

[0097] The circularity is 1.000 when the particle image is circular, 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 taken as the average circularity.

[0098] The specific measurement method is as follows: First, 20 mL of deionized water, from which impurities and other contaminants have been removed, is placed in a glass container. To this, 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 three times by mass with deionized water, is added as a dispersant.

[0099] Next, 0.02 g of the sample to be measured is added, and the mixture is dispersed using an ultrasonic disperser for 2 minutes to obtain the dispersion for measurement. During this process, the dispersion is cooled as needed 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 2 mL of the aforementioned Contaminon N is added to this water tank.

[0100] For the measurement, the flow-type particle image analyzer equipped with a standard objective lens (10x) is used, and the particle sheath "PSE-900A" (manufactured by Sysmex Corporation) is used as the sheath liquid. The dispersion prepared according to the above procedure is introduced into the flow-type particle image analyzer, and 3000 toner particles are measured in HPF measurement mode and total count mode. Then, the binarization threshold for particle analysis is set to 85%, and the analyzed particle diameter is limited to a circular equivalent diameter of 1.985 μm or more and less than 39.69 μm, and the average circularity of the toner particles is determined.

[0101] Before starting the measurement, autofocus adjustment should be performed using standard latex particles. For example, "RESEARCH AND TEST PARTICLES Latex Microsphere Suspensions 5200A" from Duke Scientific should be used after dilution with deionized water. Subsequently, it is preferable to perform focus adjustment every two hours from the start of the measurement.

[0102] In this embodiment, a flow-type particle image analyzer that has been calibrated by Sysmex Corporation and for which a calibration certificate has been issued by Sysmex Corporation is used. Except for limiting the analyzed particle size to a circular equivalent diameter of 1.985 μm or more and less than 39.69 μm, measurements are performed under the measurement and analysis conditions at the time the calibration certificate was issued.

[0103] <Observation of the pointed ends of inorganic oxide particles> In the image in which the inorganic oxide particles described above are observed, the angle of the edges is calculated using the image processing software "Image-Pro Plus ver.4.0 (Media Cybernetics)". Specifically, as shown in Figure 1, the edges of the inorganic oxide particles are detected using the Edge Detector of the above software.

[0104] A circle with a radius of 200 nm (indicated as 2 in the figure) is drawn with the detected edge as the center. Two straight lines are drawn connecting the intersection of the circle and the outline of the inorganic oxide particle (1 in the figure) to the edge, and a line with a width of 50 nm is drawn with these lines as the center (these are the two lines extending from the center of circle 2 to the outline of circle 2 in the figure). The "enlarged view of the line portion" in the figure shows the outline of the inorganic oxide particle contained within these two 50 nm wide lines. Here, if the outline of the inorganic oxide particle does not fit within the width of 50 nm, that edge is not analyzed. The angle formed by the two 50 nm wide lines (3 in the figure) is analyzed using the above software, and if the angle is 90 degrees or less, it is determined that the inorganic oxide particle has a pointed part.

[0105] By observing the cross-sections of 100 toner particles, if more than 90% of the inorganic oxide particles had sharp edges, it was determined that the inorganic oxide particles contained in those toner particles had sharp edges.

[0106] <Compositional analysis of the binding resin> • Method for separating the binding resin Dissolve 100 mg of toner in 3 ml of chloroform. Next, remove insoluble matter by suction filtration using a syringe fitted with a sample processing filter (pore size 0.2 μm to 0.5 μm, for example, a Myshori Disc H-25-2 (Tosoh Corporation)). Introduce the soluble matter into a preparative HPLC (apparatus: Nippon Analytical Engineering Co., Ltd. LC-9130 NEXT preparative column [60 cm], exclusion limits: 20000, 70000, 2 columns linked) and deliver the chloroform eluent. Once a peak is confirmed on the resulting chromatograph, separate the retention time at which the molecular weight of a monodisperse polystyrene standard sample is 2000 or more. Dry and solidify the resulting solution to obtain a binder resin.

[0107] • Identification of the binding resin components and measurement of their mass ratios using nuclear magnetic resonance spectroscopy (NMR). 20 mg of toner is mixed with 1 mL of deuterated chloroform, and the NMR spectrum of the protons of the dissolved binder resin is measured. From the obtained NMR spectrum, the molar ratio and mass ratio of each monomer can be calculated, and the content of constituent monomer units of the binder resin, such as styrene-acrylic resin, can be determined. For example, in the case of styrene-acrylic copolymer, the composition ratio and mass ratio can be calculated based on the peak around 6.5 ppm derived from styrene monomer and the peak around 3.5-4.0 ppm derived from acrylic monomer. In the case of a copolymer of polyester resin and styrene-acrylic resin, the molar ratio and mass ratio are calculated by combining the peaks derived from each monomer constituting the polyester resin and the peak derived from the styrene-acrylic copolymer to determine the monomer unit content of the polyester resin. NMR device: JEOL RESONANCE ECX500 Observed nucleus: Proton Measurement mode: Single pulse Reference peak: TMS

[0108] <Weight average molecular weight Mw measurement> The molecular weight distribution of the toner (weight-average molecular weight Mw, number-average molecular weight Mn, peak molecular weight) is measured by gel permeation chromatography (GPC) as follows.

[0109] First, the sample is dissolved in tetrahydrofuran (THF) at room temperature for 24 hours. Then, the resulting solution is filtered through a solvent-resistant membrane filter, "Myshoridisk" (manufactured by Tosoh Corporation), with a pore diameter of 0.2 μm, to obtain the sample solution. The sample solution is adjusted so that the concentration of components soluble in THF is 0.8% by mass. This sample solution is then used for measurement under the following conditions. Equipment: HLC8120GPC (Detector: RI) (Manufactured by Tosoh Corporation) • Columns: Shodex KF-801, 802, 803, 804, 805, 806, 807 (7 columns, manufactured by Showa Denko) Eluent: Tetrahydrofuran (THF) ·Flow rate: 1.0ml / min Oven temperature: 40.0℃ • Sample injection volume: 0.10 ml

[0110] To calculate the molecular weight of the sample, a molecular weight calibration curve created using standard polystyrene resin (for example, "TSK Standard Polystyrene F-850, F-450, F-288, F-128, F-80, F-40, F-20, F-10, F-4, F-2, F-1, A-5000, A-2500, A-1000, A-500", manufactured by Tosoh Corporation) is used.

[0111] <Measurement of coverage rate of external additives> Using a FE-SEM S-4800 (manufactured by Hitachi, Ltd.), photographs of the toner particle surface were taken at a magnification of 50,000x. From the observed images, the following calculations were performed using the image processing software "ImageJ". Through particle analysis, particles originating from the external additive in the image were selected in the software. Next, the area of ​​the selected area was displayed from the measurement settings. By dividing this value by the area of ​​the entire field of view, the coverage rate of the external additive in that field of view was obtained.

[0112] The image capture conditions for the S-4800 are as follows:

[0113] (1) Sample preparation A thin layer of conductive paste is applied to the sample stage (aluminum sample stage, 15mm x 6mm), and toner is sprayed onto it. Excess toner is then removed from the sample stage by air blowing, and it is allowed to dry completely. The sample stage is then placed in the sample holder, and the sample stage height is adjusted to 36mm using the sample height gauge.

[0114] (2) Setting observation conditions for S-4800 Fill the anti-contamination trap attached to the S-4800 housing with liquid nitrogen until it overflows, and leave it for 30 minutes. Start the S-4800's "PC-SEM" and perform flushing (cleaning of the FE tip, which is the electron source). Click on the acceleration voltage display section of the control panel on the screen, and press the [Flushing] button to open the flushing execution dialog. Confirm that the flushing intensity is 2 and execute. Confirm that the emission current due to flushing is 20-40 μA. Insert the sample holder into the sample chamber of the S-4800 housing. Press [Origin] on the control panel to move the sample holder to the observation position.

[0115] Click the acceleration voltage display to open the HV settings dialog, and set the acceleration voltage to [1.1kV] and the emission current to [20μA]. In the [Basic] tab of the operation panel, set the signal selection to [SE], select [U] and [+BSE] for the SE detector, and select [LA100] in the selection box to the right of [+BSE] to enter the mode for observing backscattered electron images. Also in the [Basic] tab of the operation panel, set the probe current to [NormAl], the focus mode to [UHR], and the WD to [4.5mm] in the electron optical system condition block. Press the [ON] button on the acceleration voltage display of the control panel to apply the acceleration voltage.

[0116] (3) Calculation of the average particle size (D1) of toner Drag within the magnification display area of ​​the control panel to set the magnification to 5000 (5k)x. Rotate the focus knob [COARSE] on the control panel until the image is somewhat in focus, then adjust the aperture alignment. Click [Align] on the control panel to display the alignment dialog and select [Beam]. Rotate the STIGMA / ALIGNMENT knob (X,Y) on the control panel to move the displayed beam to the center of the concentric circle. Next, select [Aperture] and rotate the STIGMA / ALIGNMENT knob (X,Y) one by one to stop or minimize the movement of the image. Close the aperture dialog and focus using autofocus. Repeat this operation two more times to focus.

[0117] (4) Focus adjustment For the toner particles with a number-average particle size (D1) of ±0.1 μm obtained in (3) above, with the midpoint of the maximum diameter aligned to the center of the measurement screen, drag within the magnification display area of ​​the control panel to set the magnification to 10000 (10k) times.

[0118] Rotate the focus knob [COARSE] on the control panel until the image is somewhat in focus, then adjust the aperture alignment. Click [Align] on the control panel to display the alignment dialog, and select [Beam]. Rotate the STIGMA / ALIGNMENT knob (X,Y) on the control panel to move the displayed beam to the center of the concentric circle.

[0119] Next, select [Aperture] and rotate the STIGMA / ALIGNMENT knobs (X,Y) one by one to stop or minimize the movement of the image. Close the Aperture dialog and focus using autofocus. Then, set the magnification to 50,000 (50k)x and adjust the focus using the focus knob and STIGMA / ALIGNMENT knob as described above, and focus again using autofocus. At this point, since the accuracy of the coverage measurement tends to decrease if the inclination angle of the observation surface is large, when adjusting the focus, select a setting where the entire observation surface is in focus simultaneously, and analyze the surface with as little inclination as possible.

[0120] (5) Save the image Brightness adjustment is performed using ABC mode, and a photograph is taken and saved at a size of 640 x 480 pixels. The following analysis is performed using this image file. One photograph is taken for each toner, and images are obtained for 25 toner particles.

[0121] <Measurement of toner particle size> A precision particle size distribution analyzer using the pore electrical resistance method (product name: Coulter Counter Multisizer 3) and dedicated software (product name: Beckman Coulter Multisizer 3 Version 3.51, manufactured by Beckman Coulter) are used. An aperture diameter of 100 μm is used, and measurements are taken with 25,000 effective measurement channels. The measurement data is then analyzed and calculated. The electrolytic aqueous solution used for measurement is prepared by dissolving special grade sodium chloride in ion-exchanged water to a concentration of approximately 1% by mass; for example, ISOTON II (product name) manufactured by Beckman Coulter can be used. Before performing the measurement and analysis, the dedicated software is configured as follows.

[0122] 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 (product name), and check the box for flushing the aperture tube after measurement.

[0123] 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.

[0124] 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. Add approximately 0.3 mL of a diluted solution of Contaminon N (trade name) (10% by mass aqueous solution of neutral detergent for cleaning precision measuring instruments, manufactured by Wako Pure Chemical Industries, Ltd.) diluted three times by mass with deionized water. (3) An ultrasonic dispersor with an electrical output of 120W, incorporating two oscillators with an oscillation frequency of 50kHz, with their phases shifted by 180 degrees. (Product name: Ultrasonic Dispersion System Tetora150, manufactured by Nikko Bios Co., Ltd.) Add a predetermined amount of deionized water and approximately 2 mL of Contaminon N (product name) to the 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) With the electrolytic aqueous solution in the beaker of (4) being irradiated with ultrasonic waves, approximately 10 mg of toner (particles) is added little by little to the electrolytic aqueous solution and dispersed. Then, ultrasonic dispersion treatment is continued for another 60 seconds. In ultrasonic dispersion, the water temperature in the water tank is appropriately adjusted so that it is 10°C or higher and 40°C or lower. (6) Using a pipette, the electrolytic aqueous solution of (5) in which the toner (particles) is dispersed is dropped into the round-bottom beaker of (1) installed in the sample stand, and adjusted so that the measured concentration becomes approximately 5%. Then, the measurement is carried out until the number of measured particles reaches 50,000. (7) The measurement data is analyzed with the dedicated software attached to the device to calculate the weight average particle diameter (D4). When set to graph / volume% in the dedicated software, the "average diameter" on the "analysis / volume statistical value (arithmetic mean)" screen is the weight average particle diameter (D4). When set to graph / number% in the dedicated software, the "average diameter" on the "analysis / number statistical value (arithmetic mean)" screen is the number average particle diameter (D1).

Example

[0125] Hereinafter, the present invention will be described more specifically with production examples and examples, but these do not limit the present invention in any way. All parts in the following formulations indicate parts by mass.

[0126] <Production Example of Inorganic Oxide Particles 1> A mixed gas with a volume ratio of argon to oxygen of 3:1 was introduced into the reaction vessel and replaced with air. Into this reaction vessel, oxygen gas was supplied at 40 (m 3 / hr) and hydrogen gas was supplied at 20 (m 3 / hr), and a combustion flame composed of oxygen - hydrogen was formed using an ignition device. Next, the raw material metal silicon powder was introduced into this combustion flame with a hydrogen carrier gas at a pressure of 147 kPa (1.5 kg / cm 2 ) to form a dust cloud. This dust cloud was ignited by the combustion flame to cause an oxidation reaction due to a dust explosion. After the oxidation reaction, the inside of the reaction vessel was cooled to obtain inorganic oxide particles 1 with a number average particle diameter of 2.68 μm (2680 nm).

[0127] <Manufacturing examples of inorganic oxide particles 2-4, 6, 7, and 12> Inorganic oxide particles 1 were crushed using a pulverizer (manufactured by Hosokawa Micron Corporation) while controlling the rotation speed, screen size, and number of passes to obtain inorganic oxide particles 2 with a number-average particle size of 1.54 μm (1540 nm). Furthermore, inorganic oxide particles 3, 4, 6, 7, and 12 were obtained by crushing while adjusting the rotation speed, screen size, and number of passes of the pulverizer. The number-average diameters of the obtained inorganic oxide particles are shown in Table 1.

[0128] <Example of manufacturing inorganic oxide particles 5> A gas mixture of argon and oxygen in a volume ratio of 3:1 was introduced into the reaction vessel and replaced with air. 40 ml of oxygen gas was then added to this reaction vessel. 3 ( / hr) and hydrogen gas 20 (m³ 3 A supply was placed at 0.5 kg / cm² and an ignition device was used to form a combustion flame consisting of oxygen and hydrogen. Then, a pressure of 0.5 kg / cm² was added to this combustion flame. 3 Metallic silicon powder was introduced using a hydrogen carrier gas to form a dust cloud. This dust cloud was ignited with a combustion flame, causing an oxidation reaction via a dust explosion. After the oxidation reaction, the reaction vessel was cooled to obtain silica powder with a number-average particle size of 3.44 μm.

[0129] This silica powder was pulverized while adjusting the rotation speed, screen size, and number of passes of the pulverizer to obtain silica particles 5. The number-average diameter of the obtained inorganic oxide particles is shown in Table 1.

[0130] <Example of manufacturing inorganic oxide particles 8> Ilmenite ore was dried and crushed, then pulverized / extracted by treatment with concentrated sulfuric acid. After removing unreacted ore, iron sulfate was decrystallized. The obtained titanyl sulfate was treated with an aqueous sodium hydroxide solution to pH 9.0, followed by desulfurization. Then, it was neutralized to pH 5.8 with hydrochloric acid and washed with filtered water. After calcination in a heating furnace, the material was crushed while adjusting the rotation speed of the pulverizer, screen size, and number of passes to obtain titanium oxide particles 8. The number-average diameter of the obtained inorganic oxide particles is shown in Table 1.

[0131] <Example of manufacturing inorganic oxide particles 9> Magnesium oxide powder (Pyroxma 3320, manufactured by Kyowa Chemical Co., Ltd.) was pulverized while adjusting the rotation speed, screen size, and number of passes of the pulverizer to obtain magnesium oxide particles of inorganic oxide particle size 9. The number-average diameter of the obtained inorganic oxide particles is shown in Table 1.

[0132] <Example of manufacturing inorganic oxide particles 10> Aluminum oxide was purified using bauxite as a raw material by the Bayer process. Sodium hydroxide was added to the bauxite and heated and dissolved at 250°C. After removing insoluble matter by filtration, the aluminum hydroxide was recovered as a solid by cooling. This aluminum hydroxide was heated and dehydrated at 1050°C to obtain aluminum oxide. Subsequently, the material was pulverized while adjusting the rotation speed of the pulverizer, screen size, and number of passes to obtain aluminum oxide particles with an inorganic oxide particle count of 10. The number-average diameter of the obtained inorganic oxide particles is shown in Table 1.

[0133] <Example of manufacturing inorganic oxide particles 11> Ilmenite ore was dried and crushed, then pulverized / extracted by treatment with concentrated sulfuric acid. After removing unreacted ore, iron sulfate was decrystallized. Sodium hydroxide aqueous solution was added to the obtained titanyl sulfate to adjust the pH to 9.0, and desulfurization treatment was performed. Subsequently, the pH was neutralized to 5.8 with hydrochloric acid, and the mixture was filtered and washed. Water was added to the washed cake to make a slurry with a TiO2 concentration of 1.5 mol / L, and then hydrochloric acid was added to adjust the pH to 1.5 and gelatinization treatment was performed. The desulfurized and gelatinized metatitanic acid was collected as TiO2 and added to a 3 L reaction vessel. Strontium chloride aqueous solution was added to the gelatinized metatitanic acid slurry to a SrO / TiO2 molar ratio of 1.18, and the TiO2 concentration was adjusted to 0.9 mol / L.

[0134] Next, the mixture was heated to 90°C while stirring, and then 444 mL of 10N sodium hydroxide aqueous solution was added over 50 minutes while microbubbling nitrogen gas at 600 ml / min. After that, the mixture was stirred at 95°C for 1 hour while microbubbling nitrogen gas at 400 ml / min. Subsequently, the reaction slurry was rapidly cooled to 12°C by stirring while 10°C cooling water was flowed through the jacket of the reaction vessel, and then neutralized with hydrochloric acid. After stirring for 1 hour, the mixture was filtered and separated. After calcination in a heating furnace, the mixture was pulverized while adjusting the rotation speed of the pulverizer, screen size, and number of passes to obtain strontium titanate inorganic oxide particles 11. The number-average diameter of the obtained inorganic oxide particles is shown in Table 1.

[0135] [Table 1]

[0136] <Example of Toner 1 manufacturing> • Binding resin A: 80.0 parts (Styrene-acrylic resin with a mass ratio of styrene to n-butyl acrylate of 78:22; Mw=180000, Tg=58℃) • Binding resin B: 20.0 parts (Styrene-acrylic resin with a mass ratio of styrene to n-butyl acrylate of 78:22; Mw=5300, Tg=58℃) Paraffin wax (HNP-9, Nippon Seiro): 5.0 parts ·Inorganic oxide particles 2: 2.0 parts • 3,5-di-t-butylsalicylate aluminum compound: 0.5 parts • Carbon Black: 5.0 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. -1After 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 to 25°C 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.). The material was classified using a multi-part classifier utilizing the Coanda effect to obtain toner matrix particles 1 with a weight-average particle size (D4) of 9.0 μm.

[0137] To 100 parts of the obtained toner matrix particles, 2.0 parts of hydrophobic silica microparticles (surface treated with 15% by mass of hexamethyldisilazane, with an average primary particle size of 50 nm) were added, and the mixture was mixed in a Henschel mixer (FM-75 model, manufactured by Mitsui Mining Co., Ltd.) at a rotation speed of 30s. -1 The mixture was mixed for 10 minutes of rotation, and inorganic particles were attached to the surface of the toner matrix particles.

[0138] Next, the surface treatment was carried out using the hot air surface treatment apparatus shown in Figure 2. The conditions for surface modification were a raw material supply rate of 1.0 kg / hr and a hot air flow rate of 1.4 m³. 3 / min, hot air discharge temperature 180°C, cold air temperature 3°C, cold air flow rate 1.2m³ 3 / min, absolute moisture content 3.0g / m² 3 Surface treatment was performed.

[0139] Next, using a wind-powered classifier utilizing the Coanda effect ("Elbow Jet Lab EJ-L3," manufactured by Nippon Steel Mining Co., Ltd.), fine and coarse powders were simultaneously classified and removed to obtain toner particles 1.

[0140] Next, 1 part toner particles (1 part) and 2 parts hydrophobic silica fine particles (Silica particles RY200, manufactured by Nippon Aerosil Co., Ltd.) were placed in a Henschel mixer (FM-75 model, manufactured by Mitsui Miike Chemical Machinery Co., Ltd.). Mixing was carried out at a temperature of 30°C with the peripheral speed of the rotating blades set to 35 m / sec and the mixing time set to 8 minutes. Toner 1 was obtained by passing the mixture through a sieve with a mesh size of 45 μm. The formulation of toner 1 is shown in Table 2, and its physical properties are shown in Table 3.

[0141] <Manufacturing examples for toners 2, 5-10, and 15-18> In the manufacturing example of Toner 1, the procedure was carried out similarly except that inorganic oxide particles listed in Table 2 were used, and Toners 2, 5-10, and 15-18 were obtained. The formulations of Toners 2, 5-10, and 15-18 are shown in Table 2, and their physical properties are shown in Table 3.

[0142] <Example of Toner 3 production> In the manufacturing example of Toner 1, the procedure was carried out similarly except that the discharge temperature of the hot air used to surface-treat the toner particles with inorganic particles attached to their surface was changed to 120°C, and Toner 3 was obtained. The formulation of Toner 3 is shown in Table 2 and its physical properties are shown in Table 3.

[0143] <Example of Toner 4 manufacturing> In the manufacturing example of Toner 1, the procedure was carried out similarly except that the discharge temperature of the hot air used to surface-treat the toner particles with inorganic particles attached to their surface was changed to 100°C, and Toner 4 was obtained. The formulation of Toner 4 is shown in Table 2 and its physical properties are shown in Table 3.

[0144] <Manufacturing examples for toners 11 and 12> In the manufacturing example of Toner 1, the procedure was carried out similarly except for changing the amount of external additives as shown in Table 2, toners 11 and 12 were obtained. The formulations of toners 11 and 12 are shown in Table 2, and their physical properties are shown in Table 3.

[0145] <Example of Toner 13 manufacturing> In the manufacturing example of Toner 1, the binder resin C was used as shown in Table 2, in an amount of 100.0 parts ([polyoxypropylene(2.2)-2,2-bis(4-hydroxyphenyl)propane:polyoxyethylene(2.2)-2,2-bis(4-hydroxyphenyl)propane:terephthalic acid:trimellitic acid = 80:20:85:15]). The procedure was carried out similarly except for the change, and toner 13 was obtained. The formulation of toner 13 is shown in Table 2, and its physical properties are shown in Table 3.

[0146] <Example of Toner 14 manufacturing> In the manufacturing example of Toner 1, the procedure was carried out similarly except that the binder resin was changed to 100.0 parts of binder resin A, as shown in Table 2, toner 14 was obtained. The formulation of toner 14 is shown in Table 2, and its physical properties are shown in Table 3.

[0147] <Manufacturing examples for toners 19 and 20> In the manufacturing example of toner 1, the procedure was carried out similarly except that inorganic oxide particles listed in Table 2 were used, and toners 19 and 20 were obtained. The formulations of toners 19 and 20 are shown in Table 2, and their physical properties are shown in Table 3.

[0148] <Example of Toner 21 manufacturing> In the manufacturing example of Toner 1, 100.0 parts of toner matrix particles and 2.0 parts of hydrophobic silica fine particles (silica particles RY200 manufactured by Nippon Aerosil Co., Ltd.) were placed in a Henschel mixer (FM-75 model manufactured by Mitsui Miike Chemical Machinery Co., Ltd.) and mixed at a temperature of 30°C with a rotating blade peripheral speed of 35 m / sec and a mixing time of 8 minutes. Toner 21 was obtained by passing the mixture through a sieve with a mesh size of 45 μm. The formulation of Toner 21 is shown in Table 2 and its physical properties are shown in Table 3.

[0149] [Table 2]

[0150] [Table 3]

[0151] [Examples 1-18, Comparative Examples 1-3] Evaluation tests were conducted on toners 1-18 for the examples and toners 19-21 for the comparative examples, respectively, according to the following procedures.

[0152] <Evaluation of transcription properties> Toner was filled into a cartridge (CF230X) for an HP printer (LaserJet Pro m203dw) that employs a cleanerless system, and its transfer performance was evaluated in a low-temperature, low-humidity environment (15.0°C, 10.0%RH).

[0153] When the transfer current was adjusted to 8.0 μA, the residual toner on the electrostatic latent image carrier (photoreceptor) during solid image formation was taped off using transparent polyester adhesive tape (product name: Polyester Tape No. 5511, supplier: Nichiban Co., Ltd.). The density of the paper with the removed adhesive tape attached was calculated by subtracting the density of the paper with only the adhesive tape attached, and the resulting density difference was calculated.

[0154] The concentration was measured using a REFLECTMETER MODEL TC-6DS manufactured by Tokyo Denshoku Co., Ltd. A green filter was used.

[0155] Evaluations were conducted at initial stages, after 3,500 sheets were fed, and after 7,000 sheets were fed.

[0156] The evaluation criteria are as follows: A score of C or higher is considered good. The results are shown in Table 4. A: The concentration difference is less than 5.0, which is very good. B: A concentration difference of 5.0 or more and less than 10.0 is considered good. C: The concentration difference is 10.0 or greater and less than 15.0. D: The concentration difference is 15.0 or greater.

[0157] <Evaluation of Cleanability> The cleaning performance was evaluated in the same way as the transfer performance evaluation, by filling a cartridge (CF230X) for an HP printer (LaserJet Pro m203dw) with toner and performing the cleaning performance in a low-temperature, low-humidity environment (15.0°C, 10.0%RH).

[0158] As shown in Figure 3, an image was printed with a block-shaped solid black image covering one full rotation of the developing sleeve, followed by a solid halftone image underneath. The extent to which the history of the image from the first rotation of the developing sleeve appeared in the halftones from the second rotation onward was then evaluated by visual inspection of the images.

[0159] Evaluations were conducted after 2,000 sheets were fed, 3,500 sheets were fed, and 7,000 sheets were fed.

[0160] The evaluation criteria are as follows: A score of C or higher is considered good. The results are shown in Table 4. A: There is absolutely no difference in shade. B: Slight differences in shade are visible. C: Differences in shade are visible. D: The difference in shade can be seen even after the third wrap of the sleeve.

[0161] In a cleanerless system, as shown in Figure 4 which outlines the printer's process cartridge, there is no cleaning element for the photoreceptor. Therefore, all toner remaining on the photosensitive drum 11 without being transferred to the paper reaches the charging roller 12. Most of the toner remaining on the photosensitive drum 11 is negatively charged by friction with the charging roller 12 and is collected in the developing sleeve 21 without adhering to the charging roller 12. However, as the charging roller becomes contaminated in the later stages of durability, the remaining toner that reaches the charging roller is no longer sufficiently negatively charged. Also, the charge difference between the photoreceptor and the developing sleeve becomes less pronounced. As a result, the remaining toner cannot be collected in the developing sleeve and appears as a ghost image from the second pass through the developing sleeve onwards.

[0162] On the other hand, even in the later stages of durability when recovery becomes difficult with the developing sleeve as described above, we believe that by using the toner with suppressed rolling properties of the present invention, it will be possible to recover the remaining toner in the developing sleeve even in a cleanerless system, and good images can be obtained.

[0163] [Table 4] [Explanation of Symbols]

[0164] 1: Inorganic oxide particles, 2: Circle, 3: Angle formed by two lines with a width of 50 nm, 11: Photosensitive drum (electrostatic latent image carrier), 12: Charging roller, 21: Developing sleeve, 100: Toner particle supply port, 101: Hot air supply port, 102: Airflow injection member, 103: Cold air supply port, 104: Second cold air supply port, 106: Cooling jacket, 114: Toner particles before surface treatment, 115: High-pressure air supply nozzle, 116: Transfer piping

Claims

1. A toner having toner particles containing a binder resin and inorganic oxide particles, The inorganic oxide particles are oxide particles containing at least one element selected from the group consisting of Si, Mg, Al, Ti, and Sr. In cross-sectional observation of the toner using a transmission electron microscope, when the area of ​​the inorganic oxide particles is Sm and the cross-sectional area of ​​the toner is St, Sm / St is 4.0% or more. In the cross-sectional observation, the standard deviation (μm) of the area Sm of the inorganic oxide particles in each of the four regions divided by the major axis of the toner and the perpendicular bisector of the major axis is measured. 2 ) is 0.40 or higher, The average circularity of the toner is 0.950 or higher. The weight-average particle size (D4) of the toner is 3.0 to 10.0 μm. A toner characterized by the following features.

2. The toner according to claim 1, wherein, in the cross-sectional observation, the major axis of the inorganic oxide particles is 400 to 3000 nm.

3. The toner according to claim 1 or 2, wherein, in the cross-sectional observation, the inorganic oxide particles have pointed portions.

4. The toner according to any one of claims 1 to 3, wherein, in the cross-sectional observation, the major axis of the inorganic oxide particles is 750 to 3000 nm.

5. In the cross-sectional observation, the standard deviation (μm) of the area Sm of the inorganic oxide particles is 2 The toner according to any one of claims 1 to 4, wherein the ratio is 0.50 or higher.

6. The toner according to any one of claims 1 to 5, wherein the inorganic oxide particles are silica particles.

7. The toner according to any one of claims 1 to 6, wherein, in the cross-sectional observation, the shape coefficient SF-1 of the inorganic oxide particles is 140 or more.

8. The toner according to any one of claims 1 to 7, wherein the average circularity of the toner is 0.960 or higher.

9. The toner has an external additive, The coating rate of the external additive is 75% or more. The toner according to any one of claims 1 to 8.

10. The toner according to any one of claims 1 to 9, wherein the binder resin is a styrene-acrylic resin.

11. A method for manufacturing toner having toner particles containing a binder resin and inorganic oxide particles, The manufacturing method includes a step of obtaining the toner particles, The process for obtaining the toner particles includes the steps of obtaining toner particles before surface treatment with hot air, and surface treating the toner particles before surface treatment with hot air with hot air. The step of obtaining toner particles before surface treatment with hot air includes a step of melting and kneading the binder resin and the inorganic oxide particles. The inorganic oxide particles are an oxide containing at least one element selected from the group consisting of Si, Mg, Al, Ti, and Sr. In cross-sectional observation of the toner using a transmission electron microscope, when the area of ​​the inorganic oxide particles is Sm and the cross-sectional area of ​​the toner is St, Sm / St is 4.0% or more. In the cross-sectional observation, the standard deviation (μm) of the area Sm of the inorganic oxide particles in each of the four regions divided by the major axis of the toner and the perpendicular bisector of the major axis is measured. 2 ) is 0.40 or higher, The average circularity of the toner is 0.950 or higher. The weight-average particle size (D4) of the toner is 3.0 to 10.0 μm. A method for manufacturing toner characterized by the following:

12. The method for manufacturing toner according to claim 11, wherein, in the cross-sectional observation, the inorganic oxide particles have pointed portions.

13. The method for manufacturing toner according to claim 11 or 12, wherein, in the cross-sectional observation, the shape coefficient SF-1 of the inorganic oxide particles is 140 or more.

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