Toner and toner manufacturing method

Abstract

To provide a toner that is excellent in low temperature fixability and is excellent in durability in a high temperature and high humidity severe environment, and a method for manufacturing toner.SOLUTION: A toner has toner particles containing a binder resin, wax, and inorganic oxide particles, and an external additive. The inorganic oxide particle includes, as a main component, an oxide of at least one element selected from the group consisting of Si, Mg, Al, Ti, Sr. When a thin layer obtained by cutting the toner by a microtome is observed by a transmission electron microscope (TEM), the major axis A of the inorganic oxide particle is 0.10-3.00 μm. In a test of wettability of the toner for a methanol / water mixture solvent, the concentration of methanol when the permeability of light with a wavelength of 780 nm is 50% is 5.0-30.0 volume%.SELECTED DRAWING: None

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to toners and methods for producing toners used in image forming processes such as electrophotography, electrostatic recording, and toner jet processes. [Background technology]

[0002] In recent years, there has been a demand for higher speeds and lower power consumption in printers and copiers, and the development of toners with excellent low-temperature fixability and heat-resistant storage stability is required. In response to this demand, Patent Document 1 proposes a method of achieving both low-temperature fixability and heat-resistant storage stability by using a low-melting wax and silica. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-140368 Summary of the Invention [Problem to be solved by the invention]

[0004] Although the above proposals have improved low-temperature fixability and heat-resistant storage stability, there remains the issue of durability in harsh environments such as high temperatures and humidity. As multifunction devices and printers have become more widespread and are now used in a variety of regions and environments, there is a demand for toners that are particularly durable in harsh environments such as high temperatures and humidity. Therefore, the problem to be solved by the present disclosure is to provide a toner that has excellent low-temperature fixability and excellent durability in a harsh environment of high temperature and high humidity, and a method for producing the toner. [Means for solving the problem]

[0005] The present disclosure provides toner particles containing a binder resin, a wax, and inorganic oxide particles, and a toner having an external additive, the inorganic oxide particles contain, as a main component, an oxide of at least one element selected from the group consisting of Si, Mg, Al, Ti, and Sr; when a thin piece obtained by cutting the toner with a microtome is observed with a transmission electron microscope (TEM), the major axis A of the inorganic oxide particles is 0.10 to 3.00 μm; The toner is characterized in that, in a wettability test for the toner with a methanol / water mixed solvent, the methanol concentration is 5.0 to 30.0% by volume when the transmittance of light with a wavelength of 780 nm is 50%. The present disclosure also provides a method for producing toner particles containing a binder resin, a wax, and inorganic oxide particles, and a toner having an external additive, the method comprising: The production method includes a melt-kneading step, the inorganic oxide particles contain, as a main component, an oxide of at least one element selected from the group consisting of Si, Mg, Al, Ti, and Sr; when a thin piece obtained by cutting the toner with a microtome is observed with a transmission electron microscope (TEM), the major axis A of the inorganic oxide particles is 0.10 to 3.00 μm; In a wettability test of the toner with a methanol / water mixed solvent, the methanol concentration is 5.0 to 30.0% by volume when the transmittance of light with a wavelength of 780 nm is 50%. The present invention relates to a method for producing a toner. [Effects of the Invention]

[0006] According to the present disclosure, a toner having excellent low-temperature fixability and excellent durability in a harsh environment of high temperature and high humidity, and a method for producing the toner are provided. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. [Figure 2] 1 is a graph showing an example of a methanol drop transmittance curve in a wettability test. DETAILED DESCRIPTION OF THE INVENTION

[0008] In the present disclosure, unless otherwise specified, the expressions "XX or more and YY or less" or "XX to YY" representing a numerical range mean a numerical range including the lower and upper limits, which are the endpoints. When a numerical range is described in stages, the upper and lower limits of each numerical range can be combined in any way.

[0009] In the present disclosure, "(meth)acrylic" means "acrylic" and / or "methacrylic".

[0010] The toner of the present disclosure will be described in more detail below.

[0011] [Features of the present invention] As a result of extensive research aimed at solving the problems of the conventional techniques described above, the inventors have found that the above problems can be solved by incorporating inorganic oxide particles having specific components and particle sizes into toner particles, and further by controlling the methanol concentration within a specific range when the transmittance of light with a wavelength of 780 nm is 50% in a wettability test of the toner with a methanol / water mixed solvent.

[0012] That is, the present invention provides toner particles containing a binder resin, wax, and inorganic oxide particles, and a toner having an external additive, wherein the inorganic oxide particles contain, as a main component, an oxide of at least one element selected from the group consisting of Si, Mg, Al, Ti, and Sr, and when a thin section obtained by cutting the toner with a microtome is observed under a transmission electron microscope (TEM), the major axis A of the inorganic oxide particles is 0.10 to 3.00 μm, and in a wettability test of the toner with a methanol / water mixed solvent, the methanol concentration at which the transmittance of light with a wavelength of 780 nm is 50% is 5.0 to 30.0 volume %.

[0013] The inventors believe that the reason why the effects of the present invention can be obtained by satisfying the above conditions is as follows.

[0014] In the past, methods have been considered to obtain toners with excellent low-temperature fixing properties and heat-resistant storage stability, such as incorporating low-melting wax and silica to prevent wax from seeping out in high-temperature environments but to allow the wax to seep out during fixing. However, even with this method, continuous printing in high-temperature environments has been problematic, as external forces on the toner cause the wax to seep out, changing the surface properties of the toner, and if the exuded wax grows further, it can contaminate components and cause image degradation.

[0015] On the other hand, under high temperature and high humidity conditions, external additives absorb moisture, which reduces triboelectricity and worsens fogging suppression, so to improve durability under high temperature and high humidity conditions, external additives that have been hydrophobized are generally used. However, hydrophobized external additives have the problem of promoting wax bleeding.

[0016] In the present invention, inorganic oxide particles containing, as a main component, an oxide of at least one element selected from the group consisting of Si, Mg, Al, Ti, and Sr, with a major axis A of 0.10 to 3.00 μm, which is large for inorganic particles used in toner, are incorporated into the toner particles. This facilitates wax exudation by penetrating the interface between the binder resin and the inorganic oxide particles during fixing. Furthermore, the toner surface is intentionally made hydrophilic so that the methanol concentration at 50% transmittance for 780 nm light in a methanol / water mixed solvent test is 5.0 to 30.0 volume %, thereby preventing wax from exuding to the outermost surface of the toner even under high temperature and high humidity conditions, even when subjected to external force. Furthermore, the wax remaining between the toner particles and the external additives prevents a decrease in triboelectricity due to excessive moisture absorption on the toner surface, thereby suppressing fogging under high temperature and high humidity conditions for a long period of time.

[0017] If the major diameter A is less than 0.10 μm, the effect of improving low-temperature fixing property cannot be obtained. If the major diameter A exceeds 3.00 μm, members such as drums and developing rollers will be worn away, resulting in poor durability. Regarding the surface property of the toner, if the methanol concentration is less than 5.0% by volume, the fog suppression under high temperature and high humidity deteriorates. If it exceeds 30.0% by volume, bleeding of wax in continuous printing under high temperature and high humidity cannot be suppressed, causing image defects such as developing streaks. The methanol concentration can be controlled by the amount of hydroxyl groups and the amount of water of hydration remaining in the external additive.

[0018] From the perspective of durability, it is preferable that the wax is at least one selected from the group consisting of hydrocarbon wax and ester wax. These waxes are considered to be well compatible with inorganic oxide particles and suppress excessive hygroscopicity of the hydrophilic surface of the toner.

[0019] When a thin slice obtained by cutting the toner with a microtome is observed with a transmission electron microscope (TEM), it is preferable that the shortest distance B between the inorganic oxide particles and the surface of the toner particles and the shortest distance C between the wax domain and the surface of the toner particles satisfy B < C. By having B < C, bleeding of wax under high temperature and high humidity is more suppressed, improving durability. For example, in toner production by the pulverization method, the shortest distance B can be controlled by adjusting the major diameter A of the inorganic oxide particles. Also, it can be controlled by selecting a wax that is compatible with the binder resin (for example, ester wax for styrene-acrylic resin and polyester resin) or adjusting the kneading strength. Increasing the degree of dispersion of the wax domain makes C larger, and increasing the size of the wax domain or decreasing the degree of dispersion tends to make the wax more likely to become the pulverization interface, resulting in a smaller C.

[0020] Also, it is preferable that the relationship between the major diameter A and the shortest distance B satisfies A > B. By having A > B, bleeding of wax under high temperature and high humidity is more suppressed, improving durability.

[0021] Furthermore, it is preferable that the major diameter D of the external additive satisfies the relationship A>D with respect to the major diameter A. When A>D, low-temperature fixability is improved. It is believed that this facilitates the wax seepage effect of the inorganic oxide particles during fixation.

[0022] When a thin slice obtained by cutting the toner with a microtome is observed under a transmission electron microscope (TEM), the shape factor SF-1 of the inorganic oxide particles is preferably 140 or more. An SF-1 of 140 or more improves low-temperature fixability. It is believed that the irregular shape causes anisotropy in the mobility of the inorganic oxide particles in the toner during fixation, which in turn makes it easier to achieve the wax seepage effect of the inorganic oxide particles. The method for controlling SF-1 will be described later.

[0023] Furthermore, when a thin slice obtained by cutting the toner with a microtome is observed under a transmission electron microscope (TEM), the inorganic oxide particles preferably have a pointed portion. The presence of a pointed portion improves low-temperature fixability. The presence of a pointed portion is thought to make it easier for the inorganic oxide particles to come out to the toner surface during fixation, which in turn makes it easier to achieve the wax seepage effect of the inorganic oxide particles. The method for controlling the presence or absence of a pointed portion will be described later.

[0024] The inorganic oxide particles are preferably silica, which improves low-temperature fixability. Silica is compatible with hydrocarbon waxes and ester waxes, which is thought to facilitate the wax seepage effect of the inorganic oxide particles during fixation.

[0025] The external additive preferably has a heat loss of 0.5 to 8.0% at 200 to 400°C as measured by thermogravimetry (TGA). In the present invention, this weight loss is derived from the hydroxyl groups of the external additive, and is preferred for controlling the surface properties of the toner while imparting the toner fluidity fundamentally required in electrophotographic processes. If it is less than 0.5%, it is difficult to obtain the effect of suppressing wax bleeding, and if it exceeds 8.0%, fogging suppression tends to deteriorate, both of which tend to result in a trade-off with the fluidity of the toner. The heat loss can be controlled by adjusting the degree of condensation through the reaction time during production of the external additive, the temperature of the drying process, etc.

[0026] Hereinafter, embodiments of the present invention will be described in detail.

[0027] [Inorganic oxide particles] The inorganic oxide particles of the present invention are not particularly limited in terms of the 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 metal silicon, silicon halides, and silicon compounds such as silane compounds are reacted in the gas phase, and a wet method in which a silane compound such as alkoxysilane is hydrolyzed and subjected to a condensation reaction. The silica particles usable in the toner of the present invention can be manufactured by any method. The silica particles used in the present invention preferably have a number-average particle size D1 of 0.12 to 3.60 μm. Because these particles are relatively large, 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 can instantaneously raise the temperature inside the reaction vessel above the melting point of the inorganic fine powder, making it a preferred method for obtaining large silica particles.

[0028] For example, silica particles having a diameter of about 0.10 to 5.00 μm can be produced by the gas-phase oxidation method described above, and then pulverized by a known method to obtain silica particles having a sharp edge. For example, a pulverizer or a jet mill, which has a high pulverizing capacity, can be used as a pulverizer to easily control the shape and particle size. Furthermore, the particle size distribution can be adjusted using a known classification device, as appropriate.

[0029] In particular, in order to form pointed portions on silica particles, it is preferable to include a pulverization step in the production of silica particles. According to the studies of the present inventors, it is difficult to form pointed portions using conventional production methods such as fumed silica and sol-gel silica. Furthermore, the particle size distribution can be adjusted appropriately using a known classification device.

[0030] Similarly, there are no restrictions on the production methods for oxides of Mg, Al, Ti, and Sr. For example, oxides can be produced by refining or synthesizing minerals as raw materials, and then crushed or classified as necessary to adjust the size and shape suitable for the present invention.

[0031] [Binder resin] The toner contains a binder resin, which is not particularly limited, and known materials such as vinyl resins and polyester resins can be used.

[0032] Specifically, styrene-based 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, polyacrylic acid ester, polymethacrylic acid ester, polyvinyl acetate, etc. can be used alone or in combination of two or more. The binder resin is preferably an amorphous resin. As the binder resin, styrene-based copolymers and polyester resins are preferred in terms of development characteristics, fixability, etc. The polyester resin is preferably an amorphous polyester resin. The binder resin more preferably contains a styrene-acrylic resin. Styrene-acrylic resins improve durability, and the effects of the present invention are likely to be obtained even in the latter half of the durability test, even when the life is extended.

[0033] Furthermore, the binder resin preferably has at least two peaks or shoulders in the weight average molecular weight Mw of the tetrahydrofuran soluble matter in the molecular weight distribution between 3000 and 2000000. Having at least two peaks or shoulders between 3000 and 2000000 improves durability, and the effects of the present invention can be easily obtained even in the latter half of the durability test, even when the life is extended.

[0034] 〔wax〕 Examples of the ester wax used in the present invention include waxes containing fatty acid esters as the main component, such as carnauba wax and montan acid ester wax; and fatty acid esters from which some or all of the acid components have been deoxidized, such as deoxidized carnauba wax; methyl ester compounds having a hydroxyl group obtained by, for example, hydrogenating vegetable oils and fats; saturated fatty acid monoesters, such as stearyl stearate and behenyl behenate; diesters of saturated aliphatic dicarboxylic acids and saturated aliphatic alcohols, such as dibehenyl sebacate, distearyl dodecanedioate and distearyl octadecanedioate; and diesters of saturated aliphatic diols and saturated aliphatic monocarboxylic acids, such as nonanediol dibehenate and dodecanediol distearate.

[0035] Among these waxes, it is preferable to use a bifunctional ester wax (diester) having two ester bonds in the molecular structure.

[0036] The difunctional ester wax is an ester compound of a dihydric alcohol and an aliphatic monocarboxylic acid, or an ester compound of a dihydric carboxylic acid and an aliphatic monoalcohol.

[0037] Specific examples of the aliphatic monocarboxylic acid 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.

[0038] Specific examples of the aliphatic monoalcohol include myristyl alcohol, cetanol, stearyl alcohol, arachidyl alcohol, behenyl alcohol, tetracosanol, hexacosanol, octacosanol, and triacontanol.

[0039] Specific examples of dicarboxylic acids include butanedioic acid (succinic acid), pentanedioic acid (glutaric acid), hexanedioic acid (adipic acid), heptanedioic acid (pimelic acid), octanedioic acid (suberic acid), nonanedioic acid (azelaic acid), decanedioic acid (sebacic acid), dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, hexadecanedioic acid, octadecanedioic acid, eicosane dioic acid, phthalic acid, isophthalic acid, and terephthalic acid.

[0040] 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.

[0041] Other usable waxes include paraffin wax, microcrystalline wax, petrolatum and derivatives thereof, montan wax and derivatives thereof, Fischer-Tropsch wax and derivatives thereof, hydrocarbon waxes such as polyolefin waxes such as polyethylene and polypropylene and derivatives thereof, natural waxes such as candelilla wax and derivatives thereof, higher aliphatic alcohols, fatty acids such as stearic acid and palmitic acid, and compounds thereof. The wax content is preferably 5.0 parts by mass or more and 20.0 parts by mass or less per 100.0 parts by mass of the binder resin.

[0042] [Coloring Agent] In the present invention, when a colorant is contained in the toner particles, there are no particular limitations, and the following known colorants can be used.

[0043] Yellow pigments that can be used include condensed azo compounds such as yellow iron oxide, Nabels 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, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds. Specific examples include the following:

[0044] CI Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 109, 110, 111, 128, 129, 147, 155, 168, 180.

[0045] Examples of red pigments include condensed azo compounds such as red iron oxide, permanent red 4R, lithol red, pyrazolone red, watching red calcium salt, lake red C, lake D, brilliant carmine 6B, brilliant carmine 3B, eosin lake, rhodamine lake B, and alizarin lake, diketopyrrolopyrrole compounds, anthraquinone, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. Specific examples include the following:

[0046] 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.

[0047] Examples of blue pigments include alkali blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partial chloride, copper phthalocyanine compounds such as fast sky blue and indanthrene blue BG, and derivatives thereof, anthraquinone compounds, and basic dye lake compounds. Specific examples include the following:

[0048] CI Pigment Blue 1, 7, 15, 15:1, 15:2, 15:3, 15:4, 60, 62, 66.

[0049] Examples of black pigments include carbon black and aniline black. These colorants can be used alone or in combination, or in the form of a solid solution.

[0050] The content of the colorant is preferably 3.0 to 15.0 parts by mass with respect to 100.0 parts by mass of the binder resin or polymerizable monomer.

[0051] [Charge control agent] In the present invention, the toner base may contain a charge control agent. Any known charge control agent can be used. A charge control agent that has a high charging speed and can stably maintain a constant charge amount is particularly preferred.

[0052] As the charge control agent, the following can be mentioned as the agent that controls the toner particles to be negatively charged.

[0053] Organometallic compounds and chelating compounds include monoazo metal compounds, acetylacetone metal compounds, aromatic oxycarboxylic acids, aromatic dicarboxylic acids, oxycarboxylic acid and dicarboxylic acid-based metal compounds. Other examples include aromatic oxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, anhydrides, or esters, and phenol derivatives such as bisphenols. Further examples include urea derivatives, metal-containing salicylic acid compounds, metal-containing naphthoic acid compounds, boron compounds, quaternary ammonium salts, and calixarenes.

[0054] On the other hand, examples of charge control agents that control toner particles to a positive charge include: nigrosine and nigrosine modifications such as fatty acid metal salts; guanidine compounds; imidazole compounds; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate and tetrabutylammonium tetrafluoroborate, and onium salts such as phosphonium salts analogous thereto, and lake pigments thereof; triphenylmethane dyes and lake pigments thereof (lacquering agents include phosphotungstic acid, phosphomolybdic acid, phosphotungstomolybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide, ferrocyanide, etc.); metal salts of higher fatty acids; and resin-based charge control agents.

[0055] These charge control agents can be contained alone or in combination of two or more. The amount of these charge control agents added is preferably 0.01 to 10.00 parts by mass per 100.00 parts by mass of the polymerizable monomer.

[0056] [External additives] The external additive may be a known one, and examples thereof include metal oxide fine particles (inorganic fine particles) such as silica fine particles, alumina fine particles, titania fine particles, zinc oxide fine particles, strontium titanate fine particles, cerium oxide fine particles, and calcium carbonate fine particles.

[0057] By changing the reaction conditions and drying conditions, the amount of hydroxyl groups or hydration water contained can be adjusted, and the loss on heating measured by TGA can be adjusted. The sol-gel method is preferably used as the production method.

[0058] The toner may further contain small amounts of other additives, provided that they do not have a substantial adverse effect, such as lubricant powders such as fluororesin powder, zinc stearate powder, and polyvinylidene fluoride powder; abrasives such as cerium oxide powder, silicon carbide powder, and strontium titanate powder; fluidity improvers such as titanium oxide powder and aluminum oxide powder; anti-caking agents; or organic and inorganic fine particles of opposite polarity as developability improvers. These additives may also be used after their surfaces have been subjected to hydrophobic treatment.

[0059] [Toner particle size] The weight average particle diameter (D4) of the toner is preferably 3.0 to 12.0 μm, more preferably 4.0 to 10.0 μm. When the weight average particle diameter (D4) is in the above range, good fluidity is obtained, and the latent image can be developed faithfully.

[0060] [Toner manufacturing method] The toner of the present invention can be produced by any conventionally known method without any particular limitations. Specific examples include suspension polymerization, solution suspension, emulsion aggregation, spray drying, and pulverization. Among these, pulverization is preferred. In the pulverization method, the vicinity of the inorganic oxide particles tends to form a pulverization interface during the pulverization process, making it easier for the inorganic oxide particles to be present outside the wax domain, thereby making it easier to achieve the effects of the present invention.

[0061] Specific examples of the pulverization method for producing a toner through a melt-kneading step and a pulverization step will be given below, but the method is not limited thereto.

[0062] For example, a binder resin, wax, inorganic oxide particles, and, if necessary, a colorant, a charge control agent, and other additives are thoroughly mixed using a mixer such as a Henschel mixer or a ball mill (mixing step), and the resulting mixture is melt-kneaded using a thermal kneader such as a twin-screw kneading extruder, a heated roll, a kneader, or an extruder (melt-kneading step).

[0063] The resulting melt-kneaded product is cooled and solidified, then pulverized using a pulverizer (pulverization step), and classified using a classifier (classification step) to obtain toner particles. Subsequently, the toner particles and external additives are mixed in a mixer such as a Henschel mixer (external addition step) to obtain toner.

[0064] As for the external addition conditions, the higher the rotation speed of the mixing blade and the longer the mixing time, the easier it is to make the external additive adhere uniformly to the surface of the toner base particles, and therefore, these are preferable.

[0065] However, if the rotation speed of the mixing blade is too high or the mixing time is too long, the frictional heat between the toner and the mixing blade increases, which can cause the toner to heat up and fuse. Therefore, it is preferable to actively cool the mixer by providing a water-cooling jacket on the mixing blade or mixer. It is preferable to adjust the rotation speed of the mixing blade and the mixing time so that the temperature inside the mixer is 45°C or less. Specifically, it is preferable to adjust the maximum peripheral speed of the mixing blade to 10.0 to 150.0 m / s, and the mixing time to 0.5 to 60 minutes.

[0066] The external addition step may be carried out in one stage or in two or more stages, and the mixing device, mixing conditions, and blending of the toner base particles used in each stage may be the same or different.

[0067] Examples of mixers include the following: FM Mixer (Nippon Coke and Engineering Co., Ltd.); Super Mixer (Kawata Corporation); Ribocone (Okawahara Manufacturing Co., Ltd.); Nauta Mixer, Turbulizer, Cyclomix (Hosokawa Micron Corporation); Spiral Pin Mixer (Pacific Ocean Machinery Works Co., Ltd.); and Lödige Mixer (Matsubo Corporation).

[0068] Examples of thermal kneaders include the following: KRC kneader (manufactured by Kurimoto Iron Works); Buss-Co kneader (manufactured by Buss); TEM type extruder (manufactured by Toshiba Machine Co., Ltd.); TEX twin-screw kneader (manufactured by The Japan Steel Works); PCM kneader (manufactured by Ikegai Iron Works); three-roll mill, mixing roll mill, kneader (manufactured by Inoue Manufacturing Co., Ltd.); Kneadex (manufactured by Mitsui Mining Co., Ltd.); MS-type pressure kneader, Kneader-Ruder (manufactured by Moriyama Manufacturing Co., Ltd.); and Banbury mixer (manufactured by Kobe Steel, Ltd.).

[0069] Examples of pulverizers include the following: Counter Jet Mill, Micron Jet, and Innomizer (manufactured by Hosokawa Micron Corporation); IDS-type mill and PJM jet pulverizer (manufactured by Nippon Pneumatic Mfg. Co., Ltd.); Cross Jet Mill (manufactured by Kurimoto Iron Works); Urmax (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 Kogyo Co., Ltd.); and Super Rotor (manufactured by Nisshin Engineering Co., Ltd.).

[0070] Examples of classifiers include the following: Cruseal, Micron Classifier, and Spedic Classifier (manufactured by Seishin Enterprise Co., Ltd.); Turbo Classifier (manufactured by Nisshin Engineering Co., Ltd.); Micron Separator, Turboplex (ATP), and TSP Separator (manufactured by Hosokawa Micron Corporation); Elbow Jet (manufactured by Nittetsu Mining Co., Ltd.), and Dispersion Separator (manufactured by Nippon Pneumatic Mfg. Co., Ltd.); and YM Microcut (manufactured by Yaskawa Corporation).

[0071] In addition, the following sieving devices may be used to sieve out coarse particles: Ultrasonic (manufactured by Koei Sangyo Co., Ltd.); Resonaseave, Gyrosifter (manufactured by Tokuju Kogyosho Co., Ltd.); Vibrasonic System (manufactured by Dalton Co., Ltd.); Soniclean (manufactured by Shinto Kogyo Co., Ltd.); Turbo Screener (manufactured by Turbo Kogyo Co., Ltd.); Microsifter (manufactured by Makino Sangyo Co., Ltd.); and circular vibrating sieve.

[0072] [Methods for measuring each physical property] Next, the measurement methods for each physical property will be described.

[0073] <Composition analysis of inorganic oxide particles> The inorganic oxide particles contained in the toner particles of the present invention refer to inorganic oxide particles contained in the toner particles before the external addition process. Based on cross-sectional images of toner particles observed with a transmission electron microscope (TEM), particles with 80% or more of their area located 100 nm or more inside from the outer periphery of the toner are defined as inorganic oxide particles contained in the toner particles. In addition, the composition of the inorganic oxide particles is identified by confirming that the particles are composed of oxygen and at least one element selected from Si, Mg, Al, Ti, and Sr using an energy dispersive X-ray analyzer (EDX).

[0074] An image of the cross section of a toner particle is prepared using a transmission electron microscope (TEM) as follows.

[0075] Using an osmium plasma coater (Filgen, OPC80T), a protective film of Os (5 nm) and a naphthalene (20 nm) was applied to the toner particles, which were then embedded in photocurable resin D800 (JEOL). Cross sections of the toner particles with a film thickness of 60 nm (or 70 nm) were then prepared using an ultrasonic ultramicrotome (Leica, UC7) at a cutting speed of 1 mm / s.

[0076] The obtained cross section is observed using the STEM function of a TEM (JEOL, JEM2800). The STEM probe size is 1 nm, and the image size is 1024 x 1024 pixels. Among the cross sections of the toner particles, a cross section having a diameter 0.9 to 1.1 times the weight average particle size is selected.

[0077] <Measurements of inorganic oxide particle major axis A, area Sm, shape factor SF-1, shortest distance B between inorganic oxide particle and toner surface, and shortest distance C between wax domain and toner surface> The image obtained is processed using image processing software "Image-Pro Plus ver. 4.0 (manufactured by Media Cybernetics)" to determine the major axis of the inorganic oxide particles, the shortest distance between the inorganic oxide particles and the toner surface, and the shortest distance between the wax domain and the toner surface. To calculate the major axis A, the shortest distance B, and the shortest distance C, the cross sections of 100 toner particles are observed, and the number average values ​​are defined as the major axis A of the inorganic oxide particles, the shortest distance B between the inorganic oxide particles and the toner surface, and the shortest distance C between the wax domain and the toner surface. Similarly, the cross sections of 100 toner particles are observed, the area of ​​the inorganic oxide particles is determined, and the average value is defined as the area Sm of the inorganic oxide particles.

[0078] Further, the shape factor SF-1 of the inorganic oxide particles is calculated from the major axis of the inorganic oxide particles and the area Sm of the inorganic oxide particles calculated above using the following formula. SF-1 = (longest diameter of inorganic oxide particles) 2 / Area of ​​inorganic oxide particles Sm×π / 4×100

[0079] SF-1 is calculated from the cross-section observation of 100 toner particles, and the average value is taken as the shape factor SF1 of the inorganic oxide particles.

[0080] If the wax domains are difficult to distinguish, a clear image can be obtained by further staining the cross section of the toner particle with ruthenium as described below and observing it with a TEM. Specifically, staining is performed for 15 minutes in a 500 Pa RuO gas atmosphere using a vacuum electron staining device (Filgen, VSC4R1H).

[0081] When ruthenium staining is used, the wax domains contained in the toner particles have a high contrast, making them easier to observe. When ruthenium staining is used, the amount of ruthenium atoms varies depending on the strength of the staining, so strongly stained areas have a large amount of these atoms, and the electron beam does not penetrate, appearing black in the observation image. On the other hand, weakly stained areas allow the electron beam to easily penetrate, appearing white in the observation image. The wax domains are observed as white because ruthenium penetrates less into them than other organic components that make up the toner particles.

[0082] <Observation of sharp points of inorganic oxide particles> In the image in which the inorganic oxide particles are observed, the edge angle is calculated using the image processing software "Image-Pro Plus ver. 4.0 (Media Cybernetics)." Specifically, the edge of the inorganic oxide particle (1 in the figure) is detected using the Edge Detector of the software, as shown in Figure 1.

[0083] A circle with a radius of 200 nm (circle indicated by 2 in the figure) is drawn with the detected edge at its center. Two straight lines are drawn connecting the edge and the intersection of the circle and the inorganic oxide particle outline, and a 50 nm wide line (two lines extending from the center of circle 2 to the outline of circle 2 in the figure) is drawn with these straight lines as the center. The outline of the inorganic oxide particle contained within these two 50 nm wide lines is shown as the "enlarged view of the line portion" in the figure. If the outline of the inorganic oxide particle does not fit within the 50 nm width, the edge is not analyzed. The angle formed by the two 50 nm wide lines (circle indicated by 3 in the figure) is analyzed using the software, and if the angle is 90 degrees or less, the inorganic oxide particle is determined to have a sharp portion.

[0084] The cross sections of 100 toner particles are observed, and if 90% or more of the inorganic oxide particles have a pointed portion, the inorganic oxide particles contained in the toner particles are determined to have a pointed portion.

[0085] <Measurement of the major diameter D of external additives> The major diameter D of the external additive is measured using a scanning electron microscope "S-4800" (trade name; manufactured by Hitachi, Ltd.). The toner to which the external additive has been added is observed, and the major diameters of 100 primary particles of the external additive are measured randomly in a field of view magnified 50,000 times, and the average value is taken as the major diameter D of the external additive. The observation magnification is adjusted appropriately depending on the size of the external additive.

[0086] <Binder resin composition analysis> - How to separate binder resin 100 mg of toner is dissolved in 3 ml of chloroform. Next, insoluble matter is removed by suction filtration using a syringe equipped with a sample processing filter (pore size 0.2 μm to 0.5 μm, such as a Myshoridisk H-25-2 (Tosoh Corporation)). The soluble matter is introduced into a preparative HPLC (apparatus: Japan Analytical Industry Co., Ltd. LC-9130 NEXT preparative column [60 cm], exclusion limits: 20,000 and 70,000, two columns connected), and chloroform eluent is pumped. Once a peak is confirmed in the resulting chromatographic display, fractions with retention times of molecular weights above 2,000 are collected using a monodisperse polystyrene standard sample. The resulting solution is dried and solidified to obtain the binder resin.

[0087] - Identification of binder resin components and measurement of mass ratios using nuclear magnetic resonance spectroscopy (NMR) 1 mL of deuterated chloroform is added to 20 mg of toner, and the proton NMR spectrum of the dissolved binder resin is measured. The molar and mass ratios of each monomer are calculated from the obtained NMR spectrum, and the content of the constituent monomer units of the binder resin, such as styrene-acrylic resin, can be determined. For example, in the case of a styrene-acrylic copolymer, the composition ratio and mass ratio can be calculated based on the peak at around 6.5 ppm derived from the styrene monomer and the peak at around 3.5-4.0 ppm derived from the acrylic monomer. In addition, in the case of a polyester resin and a copolymer of styrene-acrylic resin, the molar and mass ratios are calculated based on the peaks derived from each monomer constituting the polyester resin and the peak derived from the styrene-acrylic copolymer, and the content of the monomer units of the polyester resin is determined. NMR device: JEOL RESONANCE ECX500 Observation nucleus: Proton Measurement mode: Single pulse Base peak: TMS

[0088] <Measurement of weight average molecular weight Mw, number average molecular weight Mn, and peak molecular weight> The molecular weight distribution (weight average molecular weight Mw, number average molecular weight Mn, peak molecular weight) of a crystalline material, resin, or the like is measured by gel permeation chromatography (GPC) as follows.

[0089] First, the sample is dissolved in tetrahydrofuran (THF) at room temperature for 24 hours. The resulting solution is then filtered through a solvent-resistant membrane filter "Myshoridisc" (manufactured by Tosoh Corporation) with a pore size of 0.2 μm to obtain a sample solution. The sample solution is adjusted so that the concentration of components soluble in THF is 0.8 mass%. This sample solution is used for measurements under the following conditions. Apparatus: HLC8120GPC (detector: RI) (Tosoh Corporation) Column: Shodex KF-801, 802, 803, 804, 805, 806, 807 (7 columns, manufactured by Showa Denko Co., Ltd.) Eluent: tetrahydrofuran (THF) ·Flow rate: 1.0ml / min Oven temperature: 40.0℃ Sample injection volume: 0.10 ml To calculate the molecular weight of a sample, a molecular weight calibration curve prepared using standard polystyrene resins (for example, trade names "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.

[0090] <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, Inc.) are used. Measurements are performed with an aperture diameter of 100 μm and an effective number of measurement channels of 25,000. The measurement data are analyzed and calculated. The electrolyte solution used for the measurements is prepared by dissolving special-grade sodium chloride in ion-exchange water to a concentration of approximately 1% by mass; for example, ISOTON II (product name) manufactured by Beckman Coulter, Inc. can be used. Before performing measurements and analysis, the dedicated software is configured as follows:

[0091] 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 obtained using standard particles (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 (trade name), and check the option to flush the aperture tube after measurement.

[0092] In the dedicated software's "Pulse to particle size conversion setting screen," set the bin interval to logarithmic particle size, the particle size bin to 256 particle size bins, and the particle size range to 2 μm or more and 60 μm or less.

[0093] The specific measurement method is as follows. (1) Pour approximately 200 mL of the electrolyte solution into a 250 mL round-bottom glass beaker made specifically for the Multisizer 3, set it on the sample stand, and stir the stirrer rod counterclockwise at 24 revolutions per second. Then, use the "aperture flush" function of the analysis software to remove any dirt or air bubbles from inside the aperture tube. (2) Approximately 30 mL of the aqueous electrolyte solution is placed in a 100 mL flat-bottom glass beaker, and approximately 0.3 mL of a diluted solution prepared by diluting Contaminon N (trade name) (a 10% aqueous solution of a neutral detergent for cleaning precision measuring instruments, manufactured by Wako Pure Chemical Industries, Ltd.) three times by mass with ion-exchanged water is added. (3) An ultrasonic disperser (product name: Ultrasonic Dispersion System Tetora150, manufactured by Nikkaki Bios Co., Ltd.) with an electrical output of 120 W and equipped with two oscillators with an oscillation frequency of 50 kHz, with a phase difference of 180 degrees. Add a predetermined amount of ion-exchanged water and approximately 2 mL of Contaminon N (trade name) to the water tank. (4) Set the beaker (2) in the beaker fixing hole of the ultrasonic disperser, operate the ultrasonic disperser, and adjust the height of the beaker so that the resonance state of the liquid surface of the electrolytic solution in the beaker is maximized. (5) While ultrasonic waves are irradiated to the electrolyte solution in the beaker in (4), approximately 10 mg of toner (particles) is added little by little to the electrolyte solution and dispersed. The ultrasonic dispersion process is then continued for another 60 seconds. During the ultrasonic dispersion, the water temperature in the water tank is appropriately adjusted to be between 10°C and 40°C. (6) Using a pipette, add the electrolytic solution (5) containing dispersed toner particles to the round-bottom beaker (1) placed in the sample stand, and adjust the measurement concentration to approximately 5%. Then, measure the number of particles measured until it reaches 50,000. (7) The measurement data is analyzed using the dedicated software provided with the device to calculate the weight average particle size (D4). When the dedicated software is set to Graph / Volume %, the "Average diameter" on the Analysis / Volume Statistics (Arithmetic Mean) screen is the weight average particle size (D4). When the dedicated software is set to Graph / Number %, the "Average diameter" on the Analysis / Number Statistics (Arithmetic Mean) screen is the number average particle size (D1).

[0094] <Method for testing wettability with methanol / water mixed solvent> The wettability test of the toner with a methanol / water mixed solvent is carried out using a powder wettability tester "WET-100P" (manufactured by Rhesca Co., Ltd.) under the following conditions and procedures, and calculation is made from the obtained methanol drop transmittance curve.

[0095] A fluororesin-coated spindle-shaped rotor with a length of 25 mm and a maximum body diameter of 8 mm is placed in a cylindrical glass container with a diameter of 5 cm and a thickness of 1.75 mm.

[0096] 60 mL of water treated with a reverse osmosis membrane (RO water) is placed in the cylindrical glass container, and dispersion is carried out for 5 minutes using an ultrasonic disperser to remove air bubbles and the like.

[0097] 0.1 g of toner is precisely weighed and added to the mixture to prepare a sample liquid for measurement.

[0098] While stirring the spindle rotor in the cylindrical glass container at a speed of 300 rpm using a magnetic stirrer, methanol is continuously added dropwise to the measurement sample liquid through the powder wettability tester at a rate of 0.8 mL / min.

[0099] The transmittance is measured using light with a wavelength of 780 nm, and a methanol drop transmittance curve is created as shown in Figure 2. From the methanol drop transmittance curve, the methanol concentration (TA) is read when the transmittance reaches 50%.

[0100] The methanol concentration (TA; volume %) is (Volume of methanol present in the cylindrical glass container / Volume of the mixture of methanol and water present in the cylindrical glass container) x 100 The value is calculated by

[0101] <Weight loss of external additives due to heating> Measurement is performed using a thermal analyzer TGA7 manufactured by PerkinElmer, Inc. The external additive is heated from room temperature to 500°C at a heating rate of 25°C / min in a nitrogen atmosphere, and the weight loss (mass%) between 200°C and 400°C is taken as the heat loss of the external additive.

[0102] If the external additive used for external addition is available, it can be used for measurement. When the external additive separated from the surface of the toner particles is used as the measurement sample, the external additive is separated from the toner particles by the following procedure.

[0103] 1) For non-magnetic toner Add 160g of sucrose (Kishida Chemical) to 100mL of ion-exchanged water and dissolve in a hot water bath to prepare a concentrated sucrose solution. Place 31g of the concentrated sucrose solution and 6mL of Contaminon N in 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.

[0104] The centrifuge tube was shaken for 20 minutes at 350 strokes per minute using the shaker. After shaking, the solution was transferred to a glass tube (50 mL) for a swing rotor and centrifuged at 58.33 seconds using a centrifuge (H-9R; manufactured by Kokusan Co., Ltd.). -1 The dispersion is centrifuged under the conditions of 100°C, 100°F, 100°C ...

[0105] When a plurality of types of external additives are used, the desired external additive may be selected from the collected external additives by using a centrifugal separation method or the like.

[0106] 2) Magnetic toner First, 6 mL of Contaminon N (a 10% by weight aqueous solution of a pH 7 neutral detergent for cleaning precision measuring instruments, consisting of a nonionic surfactant, an anionic surfactant, and an organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) was added to 100 mL of ion-exchanged water to prepare a dispersion medium. 5 g of toner was added to this dispersion medium and dispersed for 5 minutes using an ultrasonic disperser (AS ONE Corporation VS-150). The mixture was then placed in an Iwaki Sangyo KM Shaker (model: V.SX) and shaken for 20 minutes at 350 strokes per minute.

[0107] The toner particles are then held down using a neodymium magnet, and the supernatant is collected. The supernatant is then dried to collect the external additives. If a sufficient amount of external additives cannot be collected, this process is repeated.

[0108] As in the case of non-magnetic toner, when a plurality of types of external additives are used, the desired external additive is selected from the collected external additives by using a centrifugal separation method or the like. [Example]

[0109] The present invention will be explained in more detail below with reference to Production Examples and Examples, which are not to be construed as limiting the scope of the present invention. Note that all parts in the following formulations are parts by mass.

[0110] <Production Example of Inorganic Oxide Particles 1> Ilmenite ore was dried and crushed, then digested / extracted by treatment with concentrated sulfuric acid. After removing unreacted ore, the iron sulfate was decrystallized. Aqueous sodium hydroxide solution was added to the obtained titanyl sulfate to adjust the pH to 9.0, and desulfurization was performed. It was then neutralized to pH 5.8 with hydrochloric acid, filtered, and washed with water. After calcining in a heating furnace, it was crushed while adjusting the pulverizer's screen size, rotation speed, and number of passes to obtain inorganic oxide particle 1, titanium oxide. The physical properties of inorganic oxide particle 1 are shown in Table 1.

[0111] <Production Example of Inorganic Oxide Particles 2> Magnesium oxide powder (Pyroxma 3320 manufactured by Kyowa Chemical Industry Co., Ltd.) was pulverized using a pulverizer while adjusting the screen size, rotation speed, and number of passes to obtain magnesium oxide particles of inorganic oxide particles 2. The physical properties of inorganic oxide particles 2 are shown in Table 1.

[0112] <Production Example of Inorganic Oxide Particles 3> Ilmenite ore was dried and crushed, then digested and extracted by treatment with concentrated sulfuric acid. After removing unreacted ore, iron sulfate was decrystallized. The resulting titanyl sulfate was desulfurized by adding aqueous sodium hydroxide solution to adjust the pH to 9.0, and then neutralized with hydrochloric acid to 5.8, filtered, and washed with water. Water was added to the washed cake to make a 1.5 mol / L slurry in terms of TiO2, and hydrochloric acid was added to adjust the pH to 1.5 for peptization. The desulfurized and peptized metatitanic acid was collected as TiO2 and placed in a 3-L reaction vessel. A strontium chloride aqueous solution was added to the peptized metatitanic acid slurry to a SrO / TiO2 molar ratio of 1.18, and the TiO2 concentration was adjusted to 0.9 mol / L.

[0113] Next, the mixture was heated to 90°C while stirring and mixing, and 444 mL of 10N aqueous sodium hydroxide solution was added over 50 minutes while microbubbling nitrogen gas at 600 mL / min. Then, the mixture was stirred at 95°C for 1 hour while microbubbling nitrogen gas at 400 mL / min. The reaction slurry was then rapidly cooled to 12°C while stirring while running 10°C cooling water through the reactor jacket. Hydrochloric acid was added to neutralize the mixture, and the mixture was stirred for 1 hour. After calcination in a heating furnace, the mixture was pulverized while adjusting the pulverizer's screen size, rotation speed, and number of passes to obtain inorganic oxide particle 3, strontium titanate. The physical properties of inorganic oxide particle 3 are shown in Table 1.

[0114] <Production Example of Inorganic Oxide Particles 4> Aluminum oxide was refined using bauxite as the raw material using the Bayer process. Sodium hydroxide was added to the bauxite and heated to 250°C for dissolution. Insoluble matter was removed by filtration, and then the mixture was cooled to recover aluminum hydroxide as a solid. This aluminum hydroxide was then dehydrated by heating at 1050°C to obtain aluminum oxide. Next, the aluminum oxide particles of inorganic oxide particle 4 were obtained by pulverizing the mixture while adjusting the pulverizer's screen size, rotation speed, and number of passes. The physical properties of inorganic oxide particle 4 are shown in Table 1.

[0115] <Production Example of Inorganic Oxide Particles 5> A mixed gas of argon and oxygen with a volume ratio of 3:1 was introduced into the reaction vessel to replace the atmosphere. Oxygen gas was introduced into the reaction vessel at a volume of 40 m 3 / hr) and hydrogen gas at 20 (m 3 An oxygen-hydrogen combustion flame was formed using an ignition device, and a pressure of 147 kPa (1.5 kg / cm) was applied to the combustion flame. 2 The raw material silicon metal powder was introduced using a hydrogen carrier gas of 1000 kJ / cm 2 , forming a dust cloud. This dust cloud was ignited by a combustion flame, causing an oxidation reaction due to a dust explosion. After the oxidation reaction, the reaction vessel was cooled to obtain silica powder with a number average particle size of 6.50 μm. This silica powder was pulverized using a pulverizer (manufactured by Hosokawa Micron Corporation) to obtain inorganic oxide particle 5 silica with a number average particle size of 2.83 μm. The physical properties of inorganic oxide particle 5 are shown in Table 1.

[0116] <Production Examples of Inorganic Oxide Particles 6 to 10> In the production example of silica particles 1, pulverization was performed while adjusting the screen size, rotation speed, and number of passes of the pulverizer to obtain silica inorganic oxide particles 6 to 10. The physical properties of inorganic oxide particles 6 to 10 are shown in Table 1.

[0117] [Table 1]

[0118] <External Additive 1 Manufacturing Example> A reaction vessel equipped with a thermometer and a stirrer was charged with 360.0 parts of water, and 15.0 parts of 5.0% by mass hydrochloric acid was added to obtain a homogeneous solution. 208.0 parts of tetraethoxysilane was added to the solution while stirring at 25°C, and the mixture was stirred for 5 hours to obtain Solution 1.

[0119] Next, 440.0 parts of water was placed in a separate reaction vessel equipped with a thermometer, stirrer, and dropping device, and 17.0 parts of 10.0% by mass aqueous ammonia was added to form a homogeneous solution. While stirring at 30°C (reaction temperature), 100 parts of the above solution was added dropwise over 0.4 hours, and the mixture was stirred for 6 hours (reaction time) to obtain a suspension. The resulting suspension was centrifuged to precipitate and remove the fine particles, which were then dried in a dryer at 150°C for 24 hours. The TGA heat loss adjustment temperature and time were then adjusted in the dryer to obtain the desired TGA heat loss, yielding External Additive 1. The physical properties of External Additive 1 are shown in Table 2.

[0120] <Production Examples of External Additives 2 to 7> External Additives 2 to 7 were obtained in the same manner as above, except that the manufacturing conditions for External Additive 1 were changed to those shown in Table 2. The physical properties of External Additives 2 to 7 are shown in Table 2.

[0121] <Production example of external additive 8> 500 parts of external additive 5 were placed in a polytetrafluoroethylene inner cylinder stainless steel autoclave. After replacing the atmosphere in the autoclave with nitrogen gas, 0.5 parts of HMDS (hexamethyldisilazane) and 0.1 parts of water were atomized using a two-fluid nozzle and sprayed uniformly onto the powder of external additive 5 while rotating the stirring blade attached to the autoclave at 400 rpm. After stirring for 30 minutes, the autoclave was sealed and heated at 200°C for 2 hours. Subsequently, the system was depressurized while still heated to remove ammonia, yielding external additive 8. The physical properties of external additive 8 are shown in Table 2.

[0122] [Table 2]

[0123] <Toner 1 manufacturing example> Binder resin A: 80.0 parts (Styrene acrylic resin with a mass ratio of styrene and n-butyl acrylate of 78:22; Mw = 180,000, Tg = 58°C) Binder resin B: 20.0 parts (Styrene acrylic resin with a mass ratio of styrene and n-butyl acrylate of 90:10; Mw = 5300, Tg = 58°C) Hydrocarbon wax (paraffin wax HNP-9, Nippon Seiro): 5.0 parts ·Inorganic oxide particles 1: 2.0 parts 3,5-di-t-butylsalicylic acid aluminum compound: 0.5 parts Carbon black: 5.0 parts The above materials were mixed in a Henschel mixer (FM-75 model, manufactured by Mitsui Mining Co., Ltd.) at a rotation speed of 20 s. -1 After mixing for 5 minutes, the mixture was kneaded twice in a twin-screw kneader (PCM-30, manufactured by Ikegai Corporation) set at 130°C. The resulting mixture was cooled to 25°C and coarsely pulverized to 1 mm or less using a hammer mill to obtain a coarsely pulverized product. The coarsely pulverized product was then finely pulverized using a mechanical pulverizer (T-250, manufactured by Turbo Kogyo Co., Ltd.). The mixture was classified using a multi-division classifier utilizing the Coanda effect to obtain toner precursor particles with a weight average particle size (D4) of 8.5 μm.

[0124] Next, the toner precursor particles were simultaneously classified and removed into fine powder and coarse powder using a wind classifier utilizing the Coanda effect ("Elbow Jet Lab EJ-L3", manufactured by Nittetsu Mining Co., Ltd.), to obtain toner particles 1.

[0125] Next, 100.0 parts of toner particles and 1.5 parts of external additives were charged into a Henschel mixer (FM-75 model, manufactured by Mitsui Miike Chemical Engineering Co., Ltd.), and the mixture was mixed at a temperature of 30°C with a rotating blade peripheral speed of 35 m / sec for a mixing time of 8 minutes, and passed through a sieve with 45 μm openings to obtain Toner 1. The production conditions and physical properties of Toner 1 are shown in Tables 3 and 4, respectively.

[0126] <Production examples of toners 2 to 14> Toners 2 to 14 were obtained in the same manner as in the production example of Toner 1, except that the production conditions were changed to those shown in Table 3. The production conditions and physical properties of Toners 2 to 14 are shown in Tables 3 and 4, respectively.

[0127] <Production Examples of Comparative Toners 1 to 4> Comparative toners 1 to 4 were obtained in the same manner as in the production example of toner 1, except that the production conditions were changed to those shown in Table 3. The production conditions and physical properties of comparative toners 1 to 4 are shown in Tables 3 and 4, respectively.

[0128] [Table 3] *Binder resin C is a polyester resin with a molar ratio of bisphenol A-ethylene oxide 2 mole adduct / bisphenol A-propylene oxide 2 mole adduct / terephthalic acid / dodecenyl succinic acid of 48 / 48 / 70 / 25; Mw=55000, Tg=58℃ *Binder resin D is a styrene-acrylic resin with a mass ratio of styrene and n-butyl acrylate of 78:22; Mw=55,000, Tg=58°C

[0129] [Table 4]

[0130] [Examples 1 to 14, Comparative Examples 1 to 4] To evaluate Toners 1 to 14 and Comparative Toners 1 to 4, a modified version of the commercially available Canon laser beam printer "LBP7600C" was used. The modification involved changing the gears and software of the evaluation machine itself, so that the rotation speed of the developing roller was set to rotate at 1.2 times the peripheral speed of the drum. The evaluations were carried out using the following low-temperature fixability and durability evaluations. The evaluation results are shown in Table 5.

[0131] [Evaluation of Low-Temperature Fixability] Solid image on transfer material (toner amount: 0.9 mg / cm 2 The image on the transfer sheet was evaluated by changing the fixing temperature. The fixing temperature was measured on the surface of the fixing roller using a non-contact thermometer. The transfer material was a letter-size plain paper (XEROX 4200, manufactured by XEROX Corporation, 75 g / m 2 In the present invention, a grade of C or higher is an acceptable level.

[0132] (Evaluation criteria) A: No offset at 115℃ B: Offset occurs at 115℃ C: Offset occurs at 120℃ D: Offset occurs at 125℃ E: Offset occurs at 130℃

[0133] [Durability evaluation] After completing a test of printing 5,000 and 10,000 sheets of horizontal line images with a 1% print ratio under high temperature and humidity conditions (temperature 33°C / humidity 85%RH), the test was carried out on a letter-size XEROX 4200 paper (XEROX, 75g / m 2 ) solid (toner amount: 0.6mg / cm 2 At the same time, a half-tone image (toner amount: 0.2 mg / cm) was printed out and evaluated for white streaks. 2 ) images were printed out and evaluated for dark streaks. The reflectance (%) of the non-image areas of the above solid and halftone images was measured using a "REFLECTOMETER MODEL TC-6DS" (Tokyo Denshoku Co., Ltd.). The obtained reflectance was subtracted from the reflectance (%) of unused printout paper (standard paper) measured in the same manner, and the resulting value (%) was used to evaluate fogging. The smaller the value, the more image fogging was suppressed.

[0134] (Solid image evaluation criteria) A: Not occurred B: White streaks occur in 1 to 2 places C: White streaks occur in 3 to 4 places D: White streaks occur in 5 to 6 places E: White streaks occur in 7 or more places A grade of C or above is an acceptable level.

[0135] (Halftone image evaluation criteria) A: Not occurred B: Dark streaks appear in 1 to 3 places C: Dark streaks appear in 4 to 6 places D: Dark streaks appear in 7 to 9 places E: Dark streaks appear in 10 or more places or are 0.5 mm or wider A grade of C or above is an acceptable level.

[0136] (Fog evaluation criteria) A: Less than 0.5% B: 0.5% or more and less than 1.5% C: 1.5% or more and less than 3.0% D: 3.0% or more and less than 4.5% E: 4.5% or more A grade of C or above is an acceptable level.

[0137] [Table 5] [Explanation of symbols]

[0138] 1: inorganic oxide particle, 2: circle, 3: angle formed by two lines with a width of 50 nm

Claims

1. A toner having toner particles containing a binder resin, a wax, and inorganic oxide particles, and an external additive, the inorganic oxide particles contain, as a main component, an oxide of at least one element selected from the group consisting of Si, Mg, Al, Ti, and Sr; when a thin piece obtained by cutting the toner with a microtome is observed with a transmission electron microscope (TEM), the major axis A of the inorganic oxide particles is 0.10 to 3.00 μm; In a wettability test of the toner with a methanol / water mixed solvent, the methanol concentration when the transmittance of light with a wavelength of 780 nm is 50% is 5.0 to 30.0% by volume. A toner characterized by:

2. 2. The toner according to claim 1, wherein the wax is at least one selected from the group consisting of ester waxes and hydrocarbon waxes.

3. 3. The toner according to claim 1, wherein, when the flake is observed with a transmission electron microscope (TEM), a relationship between the shortest distance B between the inorganic oxide particle and the surface of the toner particle and the shortest distance C between the wax domain and the surface of the toner particle satisfies B<C.

4. 4. The toner according to claim 1, wherein, when the flakes are observed with a transmission electron microscope (TEM), a relationship between a shortest distance B between the inorganic oxide particle and the surface of the toner particle and a major axis A of the inorganic oxide particle satisfies A>B.

5. 5. The toner according to claim 1, wherein a relationship between a major axis D of the external additive and a major axis A of the inorganic oxide particles satisfies A>D.

6. 6. The toner according to claim 1, wherein the inorganic oxide particles have a shape factor SF-1 of 140 or more when the flakes are observed with a transmission electron microscope (TEM).

7. 7. The toner according to claim 1, wherein the inorganic oxide particles have sharp points when the flakes are observed under a transmission electron microscope (TEM).

8. 8. The toner according to claim 1, wherein the inorganic oxide particles are silica particles.

9. 9. The toner according to claim 1, wherein the external additive has a heat loss of 0.5 to 8.0% at 200° C. to 400° C. as measured by thermogravimetry (TGA).

10. 10. The toner according to claim 1, wherein the binder resin is a styrene-acrylic resin.

11. A method for producing toner particles containing a binder resin, a wax, and inorganic oxide particles, and a toner containing an external additive, comprising the steps of: The production method includes a melt-kneading step, the inorganic oxide particles contain, as a main component, an oxide of at least one element selected from the group consisting of Si, Mg, Al, Ti, and Sr; when a thin piece obtained by cutting the toner with a microtome is observed with a transmission electron microscope (TEM), the major axis A of the inorganic oxide particles is 0.10 to 3.00 μm; In a wettability test of the toner with a methanol / water mixed solvent, the methanol concentration when the transmittance of light with a wavelength of 780 nm is 50% is 5.0 to 30.0% by volume. A method for producing a toner comprising the steps of:

Images