Toners and methods for producing toners

Abstract

This invention relates to toners and methods for producing toners. The toner of the subject matter comprises toner particles containing a binder resin and inorganic oxide particles, wherein the inorganic oxide particles are particles containing oxides of at least one element selected from the group consisting of Si, Mg, Al, Ti, and Sr, wherein, when the area of ​​the inorganic oxide particles, represented by Sm, and the cross-sectional area of ​​the toner, represented by St, is observed in cross-section using a transmission electron microscope, Sm / St is 4.0% or more, wherein, in cross-sectional observation, the standard deviation of the area Sm of the inorganic oxide particles occupying each of the four regions obtained by dividing the cross-section of the toner by the perpendicular bisector of the major axis and the major axis of the toner is 0.40 or more, and wherein the average roundness of the toner is 0.950 or more.

Description

Technical Field

[0001] This disclosure relates to toners for use in recording methods such as electrophotography, and methods for producing toners. Background Technology

[0002] In recent years, the environment for electronic photographic devices, such as desktop printers, has changed from one device shared by multiple people to one device used by one person, and at the same time, further improvements in image quality and miniaturization have been required.

[0003] One effective way to miniaturize the toner cartridge is to use a cleaner-free system. Most printers use their own cleaner systems, where, during the transfer step, a cleaning blade scrapes away the toner residue on the electrostatic latent image carrier (hereinafter referred to as "transfer residue toner") and collects it in a waste toner cartridge.

[0004] In contrast, cleaner-free systems can significantly help to reduce the size of the main unit because there are no such cleaning scrapers or waste toner cartridges.

[0005] At the same time, the widespread use of printers has led to a diversification of the types of paper used. In particular, when low-strength paper or paper with a large amount of filler is used among those types, so-called "paper dust" tends to be generated in large quantities during printing.

[0006] This paper dust tends to cause various problems with systems without cleaners.

[0007] In particular, in transfer systems where the toner is directly transferred from the photosensitive element to the paper, the photosensitive element and the paper are in direct contact with each other. In this case, paper dust easily adheres to the photosensitive element. The paper dust adhering to the photosensitive element is collected along with residual toner by a cleaning blade in the cleaning system. However, in systems without a cleaning system, the paper dust, along with residual toner, returns to the charging and developing steps without being collected, thus making various image defects more likely to occur.

[0008] To suppress the adhesion of paper dust to the surface of the photosensitive component as described above, it is effective to reduce the transfer current applied during the transfer step. However, when the transfer current is reduced, the transfer efficiency tends to decrease.

[0009] In an effort to improve transfer efficiency, Japanese Patent Application Publication No. 2007-140368 has attempted to subject a toner containing pulverized silica aggregates to a heat-spheroidizing process.

[0010] However, it has been found that the technology described in the aforementioned Japanese Patent Application No. 2007-140368 is insufficient to achieve a high level of simultaneous transfer and cleaning performance when the speed and lifespan of electrophotographic equipment are further increased. In particular, it has been found that problems exist in achieving simultaneous transfer and cleaning performance in systems without a cleaner. Summary of the Invention

[0011] This disclosure provides a toner that solves the aforementioned problems. Specifically, this disclosure provides a toner that simultaneously achieves high levels of transferability and cleanliness while increasing printing speed and extending print life. The inventors of this disclosure have repeatedly conducted in-depth research and have found that the aforementioned problems can be solved by the following toner, thus completing this disclosure.

[0012] Specifically, this disclosure relates to a toner comprising: toner particles containing a binder resin and inorganic oxide particles, wherein the inorganic oxide particles are particles containing oxides of at least one element selected from the group consisting of Si, Mg, Al, Ti, and Sr, wherein, when the area of ​​the inorganic oxide particles, represented by Sm, and the cross-sectional area of ​​the toner, represented by St, is observed in cross-section using a transmission electron microscope, Sm / St is 4.0% or more, wherein, in cross-sectional observation, the standard deviation of the area Sm of the inorganic oxide particles occupying each of the four regions obtained by dividing the cross-section of the toner by the perpendicular bisector of the major axis and the major axis of the toner is 0.40 or more, and wherein the average roundness of the toner is 0.950 or more.

[0013] This disclosure also relates to a method for producing a toner comprising toner particles containing a binder resin and inorganic oxide particles. The method includes obtaining toner particles, wherein obtaining the toner particles includes obtaining toner particles before hot air surface treatment and surface treating the toner particles before hot air surface treatment with hot air. Obtaining the toner particles before hot air surface treatment includes melting and mixing the binder resin and inorganic oxide particles, wherein the inorganic oxide particles are composed of elements selected from Si, Mg, Al, Ti, and Sr. The toner comprises particles of oxides of at least one element in the group, wherein, when the cross-sectional area of ​​the inorganic oxide particles is represented by Sm and the cross-sectional area of ​​the toner is represented by St in cross-sectional observation using a transmission electron microscope, Sm / St is 4.0% or more, wherein, in cross-sectional observation, the standard deviation of the area Sm of the inorganic oxide particles occupying each of the four regions obtained by dividing the cross-section of the toner by the perpendicular bisector of the major axis and the major axis of the toner is 0.40 or more, and wherein the average roundness of the toner is 0.950 or more.

[0014] Further features of this disclosure will become apparent from the following description of exemplary embodiments, with reference to the accompanying drawings. Attached Figure Description

[0015] Figure 1 This is an explanatory diagram of the pointed portion.

[0016] Figure 2 This is a cross-sectional view of a surface treatment device that uses hot air.

[0017] Figure 3 Images used to evaluate cleanliness.

[0018] Figure 4 This is a schematic cross-sectional view of the processing box. Detailed Implementation

[0019] This disclosure is described in detail below, but is not limited to the following embodiments.

[0020] [Features of this disclosure]

[0021] That is, this disclosure relates to a toner comprising: toner particles containing a binder resin and inorganic oxide particles, wherein the inorganic oxide particles are particles containing oxides of at least one element selected from the group consisting of Si, Mg, Al, Ti, and Sr, wherein, when the area of ​​the inorganic oxide particles is represented by Sm and the cross-sectional area of ​​the toner is represented by St in cross-sectional observation using a transmission electron microscope, Sm / St is 4.0% or more, wherein, in cross-sectional observation, the standard deviation of the area Sm of the inorganic oxide particles occupying each of the four regions obtained by dividing the cross-section of the toner by the perpendicular bisector of the major axis and the major axis of the toner is 0.40 or more, and wherein the average roundness of the toner is 0.950 or more.

[0022] The inventors of this disclosure have envisioned achieving the effects of this disclosure by satisfying the above conditions for the following reasons.

[0023] As a method to improve the transferability of toners, the adhesion of toners has so far been reduced by increasing their roundness. However, while increasing roundness improves rollability, this results in a deterioration in the toner's cleanability.

[0024] In contrast, the inventors have envisioned that the aforementioned problems can be solved in this disclosure by the following mechanism. When inorganic oxide particles containing at least one element selected from the group consisting of Si, Mg, Al, Ti, and Sr are introduced into a toner with high sphericity, a specific gravity difference arises between the organic and inorganic components in the toner. When the area of ​​the inorganic oxide particles, represented by Sm, and the cross-sectional area of ​​the toner, represented by St, are observed in cross-section using a transmission electron microscope, the Sm / St ratio is 4.0% or higher. In the cross-sectional observation, the standard deviation of the area Sm of the inorganic oxide particles occupying each of the four regions obtained by dividing the cross-section of the toner by the major axis and the perpendicular bisector of the major axis is 0.40 or higher. In this configuration, the specific gravity difference between the organic and inorganic components in the toner causes a bias, and the center of gravity of the toner shifts. The inventors have envisioned that, due to the foregoing, rolling properties can be suppressed even in toners with high sphericity, and satisfactory cleanliness can be achieved.

[0025] When the inorganic oxide particles are oxides containing at least one element selected from the group consisting of Si, Mg, Al, Ti, and Sr, which do not impair the electrophotographic characteristics of the electrophotographic equipment, a difference in specific gravity with the organic components in the toner can be achieved. From the viewpoint of improving the durability of the toner, silica particles are particularly preferred, and when silica particles are used, the effects of this disclosure can be easily obtained even when the lifespan of the equipment is extended, up to the latter half of its durability. Furthermore, when the Sm / St ratio is 4.0% or higher, the inorganic oxide particles are introduced in an amount sufficient to cause a difference in specific gravity in the toner. When the Sm / St ratio is less than 4.0%, the difference in specific gravity in the toner is small, and rolling properties cannot be suppressed, resulting in deteriorated cleanliness. The Sm / St ratio can be controlled by the amount and particle size of the inorganic oxide particles added.

[0026] Furthermore, when the standard deviation of Sm is less than 0.40, the shift in specific gravity difference becomes smaller, thus failing to suppress the rolling properties of the toner, resulting in deteriorated cleanliness. 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.

[0027] Furthermore, the average roundness of the toner disclosed herein is 0.950 or higher. When the average roundness is less than 0.950, the effect of reducing the adhesion of the toner becomes smaller, and its transferability deteriorates. The average roundness is preferably 0.960 or higher. The average roundness can be controlled by the conditions of the toner production method, for example, the hot air surface treatment step described later in the case of a pulverizing method.

[0028] Furthermore, in the toners disclosed herein, it is preferable that the major diameter of the inorganic oxide particles is 400 nm to 3,000 nm in cross-sectional observation using a transmission electron microscope. When the major diameter is 400 nm or more, the difference in specific gravity between the organic and inorganic components in the toner easily leads to shift, and the effects of this disclosure are readily obtained. In particular, when the toner is obtained by a pulverization production method, when the major diameter of the inorganic oxide particles is 400 nm or more, the inorganic oxide particles easily form a pulverization interface. As a result, the center of gravity of the toner easily shifts, and the effects of this disclosure are readily obtained. When the major diameter is 3,000 nm or less, durability is improved, and the effects of this disclosure are readily obtained even in the latter half of the durability period when the lifespan is extended. The major diameter is more preferably 750 nm to 3,000 nm. The major diameter of the inorganic oxide particles can be controlled by the pulverizer speed, sieve size, and number of passes during the production of the inorganic oxide particles described later. Alternatively, the major diameter can also be controlled by graded inorganic oxide particles.

[0029] Furthermore, in the toners disclosed herein, it is preferable that the inorganic oxide particles include the pointed ends described later in cross-sectional observation using a transmission electron microscope. The pointed ends of the inorganic oxide particles refer to those observed in cross-sectional observation of the toner. Figure 1 The angle shown is for portions below 90°. A specific method for determining whether inorganic oxide particles include sharp points is described below. Due to the presence of sharp points, especially when the toner is obtained through a pulverizing production method, inorganic oxide particles readily form a pulverizing interface. As a result, the center of gravity of the toner easily shifts, and the effects of this disclosure are readily achieved. The presence or absence of sharp points in inorganic oxide particles can be controlled by the pulverizer speed and slit width during the production of inorganic oxide particles.

[0030] Furthermore, preferably, the shape factor SF-1 of the inorganic oxide particles observed using a transmission electron microscope is 140 or higher. When SF-1 is 140 or higher, especially when the toner is obtained through a pulverization production method, the inorganic oxide particles readily form a pulverization interface. As a result, the center of gravity of the toner easily shifts, and the effects of this disclosure are readily achieved. The shape factor SF-1 of the inorganic oxide particles can be controlled by the pulverizer speed, sieve size, and number of passes during the production of the inorganic oxide particles.

[0031] Furthermore, preferably, the colorant of this disclosure further includes external additives, and the coverage rate of the external additives is 75% or more. When the coverage rate of the external additives is 75% or more, the effects of this disclosure can be easily obtained even in the latter half of the durability period, provided the service life is extended. The coverage rate of the external additives can be controlled by the type and amount of external additives added.

[0032] The embodiments of this disclosure are described in detail below.

[0033] [Inorganic oxide particles]

[0034] There are no particular limitations on the production methods of the inorganic oxide particles disclosed herein, and those produced by known methods can be used. In particular, as methods for producing silica particles, gas-phase methods involving the reaction of silicon compounds such as metallic silicon, silicon halides, or silane compounds in the gas phase are provided, as well as wet methods involving the hydrolysis and condensation of silane compounds such as alkoxysilanes. The production methods of silica particles suitable for the toners of this disclosure can be selected without any limitations. Since the silica particles of this disclosure are relatively large, such as 400 to 3,000 nm, a gas-phase oxidation method involving the direct oxidation of the powder raw material using a chemical flame formed by oxygen and hydrogen is particularly preferred. The gas-phase oxidation method can instantly raise the internal temperature of the reactor above the melting point of the inorganic fine powder, and is therefore preferred for producing large silica particles.

[0035] Regarding silica particles, silica particles each having a pointed tip can be obtained as follows: for example, silica particles with a diameter of approximately 3,000 nm to approximately 5,000 nm can be produced by a gas-phase oxidation method as described above, and the resulting material can be pulverized by a known method. For example, when a device with high pulverizing capacity, such as a pulverizer or jet mill, is used as the pulverizing machine, the shape and particle size of the silica particles can be easily controlled. The shape and particle size can be controlled by changing the pulverizer's rotation speed and slit width, etc. In addition, the particle size distribution can be appropriately adjusted by using a known grading device.

[0036] In particular, in order to form sharp points in each silica particle, it is preferable to include a pulverizing step in the production of the silica particles. According to the inventors' research, it is difficult to form sharp points using conventional production methods for fumed silica and sol-gel silica, etc. Furthermore, the particle size distribution can be appropriately adjusted using known grading equipment.

[0037] Similarly, for oxides of Mg, Al, Ti, and Sr, the production method can be chosen without any limitations. The size and shape of such oxides are adjusted to suit those of this disclosure by means of refining and synthesis, for example, using minerals as raw materials, and crushing and classifying the oxides as needed.

[0038] [Toner]

[0039] The toner contains a binder resin. There are no particular restrictions on the binder resin, and known materials such as vinyl-based or polyester-based resins can be used.

[0040] Specifically, polystyrene can be used, such as styrene-propylene copolymers, styrene-vinyltoluene copolymers, styrene-methyl acrylate copolymers, styrene-ethyl acrylate copolymers, styrene-butyl acrylate copolymers, styrene-octyl acrylate copolymers, styrene-methyl methacrylate copolymers, styrene-ethyl methacrylate copolymers, styrene-butyl methacrylate copolymers, styrene-octyl methacrylate copolymers, styrene-butadiene copolymers, styrene-isoprene copolymers, styrene-maleic acid copolymers, or styrene-maleic acid ester copolymers, etc., polyacrylates, polymethacrylates, or polyvinyl acetate, etc. These adhesive resins can be used alone or in combination. The adhesive resin is preferably a non-crystalline resin. As adhesive resins, from the viewpoint of developing properties and fixing properties, styrene-based copolymers and polyester resins are preferred respectively. Polyester resins are preferably non-crystalline polyester resins. The adhesive resin more preferably includes a styrene-acrylic resin. When using a styrene-acrylic resin, the durability of the toner is improved, and the effects of this disclosure are easily obtained even in the latter half of the lifespan of the electrophotographic equipment.

[0041] Furthermore, it is preferable that the molecular weight distribution of the tetrahydrofuran-soluble component of the adhesive resin contains two or more peaks or shoulders in the range of a weight-average molecular weight (Mw) of 3,000 to 2,000,000. When two or more peaks or shoulders are present in the weight-average molecular weight range of 3,000 to 2,000,000, durability is improved, and the effects of this disclosure are easily obtained even in the latter half of the durability period, provided that the service life is extended.

[0042] In this disclosure, it is preferred that the mold release agent be introduced as one of the materials used to form the toner matrix. In particular, when using ester waxes with a melting point of 60°C or higher and 90°C or lower, a plasticizing effect is easily obtained because ester waxes have excellent compatibility with binder resins.

[0043] Examples of ester waxes used in this disclosure include: waxes each comprising a fatty acid ester as a major component, such as carnauba wax and lignite ester wax; waxes obtained by removing some or all of the acid component from fatty acid esters, such as deacidified carnauba wax; methyl ester compounds having hydroxyl groups obtained, for example, by hydrogenating vegetable oils; saturated fatty acid monoesters, such as stearate and betaine; diesterization products of saturated aliphatic dicarboxylic acids and saturated aliphatic alcohols, such as dibetaine sebacate, distearate dodecanoate, and distearate octadecanoate; and diesterization products of saturated aliphatic diols and saturated aliphatic monocarboxylic acids, such as nonanediol distearate and dodecanediol distearate.

[0044] Among these waxes, difunctional ester waxes (diesters) having two ester bonds in their molecular structure are preferred.

[0045] Difunctional ester waxes are ester compounds of diols and aliphatic monocarboxylic acids, or ester compounds of dicarboxylic acids and aliphatic monools.

[0046] Specific examples of aliphatic monocarboxylic acids include myristic acid, palmitic acid, stearic acid, arachidonic acid, benzyl acid, limonitic acid, creosotenic acid, linoleic acid, beeswax acid, oleic acid, isoleic acid, linoleic acid, and linolenic acid.

[0047] Specific examples of aliphatic monools include myristol, cetyl alcohol, stearyl alcohol, arachidonic alcohol, betaine alcohol, tetracosyl alcohol, hexacosyl alcohol, octacosyl alcohol, and triacontanol.

[0048] Specific examples of dicarboxylic acids include succinic acid, glutaric acid, adipic acid, pimelic acid, octanedioic acid, azelaic acid, sebacic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, hexadecanoic acid, octadecanoic acid, eicosanoic acid, phthalic acid, isophthalic acid, and terephthalic acid.

[0049] Specific examples of diols 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-eicosenediol, 1,30-triacondiol, diethylene glycol, dipropylene glycol, 2,2,4-trimethyl-1,3-pentanediol, neopentanediol, 1,4-cyclohexanediol, spirodiol, 1,4-benzenediol, bisphenol A, and hydrogenated bisphenol A.

[0050] Examples of other release agents that may be used include: petroleum-based waxes and their derivatives, such as paraffin wax, microcrystalline wax, or petrolatum; lignite wax and its derivatives; hydrocarbon waxes and their derivatives obtained by the Fischer-Tropsch process; hydrocarbon waxes and their derivatives, such as polyethylene or polypropylene; natural waxes and their derivatives, such as carnauba wax or candelilla wax; higher fatty alcohols; and fatty acids, such as stearic acid or palmitic acid, or compounds thereof. The content of the release agent is preferably 5.0 to 20.0 parts by weight relative to 100.0 parts by weight of the binder resin or polymeric monomer.

[0051] In this disclosure, when the colorant is introduced into the toner particles, there are no particular limitations on the colorant, and the known colorants described below can be used.

[0052] As yellow pigments, yellow iron oxide, naphtha yellow, such as naphthol yellow S, Hansa yellow G, Hansa yellow 10 G, benzidine yellow G, benzidine yellow GR, quinoline yellow lake, permanent yellow NCG, and lemon yellow lake, as well as condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allyl amide compounds are used. Specific examples include the following pigments:

[0053] CI Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 109, 110, 111, 128, 129, 147, 155, 168 and 180.

[0054] As red pigments, colcothar is given, such as Permanent Red 4R, Lithol Red, Pyrazolone Red, Watching Red Calcium Salt, Lake Red C, Lake Red D, Brilliant Carmine 6B, Brilliant Carmine 3B, Eosin Lake, Rhodamine Lake B, and Alizarin Lake, as well as condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridones, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, indigo compounds, and perylene compounds. Specific examples include the following pigments:

[0055] 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 and 254.

[0056] As blue pigments, examples include basic blue lakes, Victoria blue lakes, phthalocyanine blue, metal-free phthalocyanine blue, partially chlorinated phthalocyanine blue, firm sky blue, copper phthalocyanine compounds such as indanthrene blue BG and their derivatives, anthraquinone compounds, and basic dye lake compounds. Specific examples include the following pigments:

[0057] CI Pigment Blue 1, 7, 15, 15:1, 15:2, 15:3, 15:4, 60, 62 and 66.

[0058] Carbon black and aniline black are given as black pigments. These colorants can be used alone or as mixtures thereof, and in a solid solution state.

[0059] The colorant content is preferably 3.0 to 15.0 parts by weight relative to 100.0 parts by weight of binder resin or polymeric monomer.

[0060] In this disclosure, the toner matrix may contain a charge control agent. Known charge control agents can be used as charge control agents. In particular, charge control agents having a high charging velocity and the ability to stably maintain a constant charge are preferred.

[0061] Examples of charge control agents that allow toner particles to be negatively charged include the following reagents:

[0062] These are organometallic compounds and chelating compounds, monoazo metal compounds, acetylacetone metal compounds, and aromatic oxycarboxylic acid metal compounds, aromatic dicarboxylic acid metal compounds, hydroxycarboxylic acid metal compounds, and dicarboxylic acid metal compounds. Other examples include aromatic hydroxycarboxylic acids, and aromatic mono and polycarboxylic acids, and their metal salts, anhydrides or esters, and phenolic derivatives such as bisphenols. Additionally, urea derivatives, metal-containing salicylic acid compounds, metal-containing naphtholic acid compounds, boron compounds, quaternary ammonium salts, and calixarnes are given.

[0063] Meanwhile, examples of agents that control toner particles so that the particles can be positively charged charge control agents include the following: aniline black and aniline black compounds modified with aliphatic acid metal salts; guanidine compounds; imidazole compounds; quaternary ammonium salts such as 1-hydroxy-4-naphthalenesulfonic acid tributylbenzylammonium and tetrabutylammonium tetrafluoroborate, and onium salts of analogs of the above compounds such as phosphonium salts, and their lake pigments; triphenylmethane dyes and their lake pigments (examples of lake agents include phosphotungstic acid, phosphomolybdic acid, phosphotungsmolybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide, and ferrocyanide); metal salts of higher fatty acids; and resin-based charge control agents.

[0064] These charge control agents can be introduced alone or in combination. The amount of charge control agent added is preferably 0.01 to 10.00 parts by weight relative to 100.00 parts by weight of adhesive resin or polymeric monomer.

[0065] A toner may comprise toner particles and external additives on the surface of each toner particle. Examples of external additives include known external additives.

[0066] Examples of external additives may include fine particles of metal oxides (inorganic fine particles), such as fine particles of silica, fine particles of alumina, fine particles of titanium dioxide, fine particles of zinc oxide, fine particles of strontium titanate, fine particles of cerium oxide, and fine particles of calcium carbonate.

[0067] In toners, other external additives can be used in small quantities to the extent that they do not have a substantial negative impact on the toner. Examples include: lubricant powders such as fluoropolymer powder, zinc stearate powder, or polyvinylidene fluoride powder; abrasives such as cerium oxide powder, silicon carbide powder, or strontium titanate powder; flowability enhancers such as titanium oxide powder or alumina powder; anti-caking agents; or fine organic and inorganic particles with opposite polarities as developer enhancers. These additives can be used after their surfaces have been hydrophobically treated.

[0068] The weight-average particle size (D4) of the toner is preferably 3.0 μm to 12.0 μm, more preferably 4.0 μm to 10.0 μm. When the weight-average particle size (D4) falls within the above range, satisfactory flowability is obtained, and the latent image can be faithfully developed.

[0069] [Production method of colorant]

[0070] Conventionally known methods can be used as production methods for the toners disclosed herein without any particular limitations. Specific examples include suspension polymerization, dissolution suspension polymerization, emulsion polymerization, spray drying, and pulverization. A preferred method includes the pulverization process comprising the steps of melting and mixing binder resin and inorganic oxide particles, and surface-treating the toner particles with hot air. According to the pulverization method, the inorganic oxide particles readily form a pulverization interface during the pulverization step, and the presence of inorganic oxide particles within the toner particles readily leads to displacement, resulting in readily achieving the effects of this disclosure.

[0071] The pulverization method for producing colorants by means of melting and mixing steps and pulverization steps is specifically described below, but this disclosure is not limited thereto.

[0072] For example, the binder resin, inorganic oxide particles, and, if necessary, colorants, release agents, charge control agents, and other additives are thoroughly mixed using a mixer such as a Henschel mixer or a ball mill (mixing step). The resulting mixture is then melted and compounded using a hot compounding mill such as a twin-screw compounding extruder, heated rollers, a compounding mill, or an extruder (melting and compounding step).

[0073] After cooling and solidifying the resulting melt and compound product, the product is pulverized using a pulverizer (pulverization step). The product is then classified using a classifier (classification step) to provide toner particles. The toner particles can be used directly as a toner. If necessary, the toner particles and external additives can be mixed using a mixer, such as a Henschel mixer, to provide a toner.

[0074] Examples of mixers include the following: FM mixer (manufactured by Nippon Coke & Engineering Co., Ltd.); super mixer (manufactured by Kawata Mfg. Co., Ltd.); Ribocone (manufactured by Okawara Mfg. Co., Ltd.); Nauta mixer, Turturizer and Cyclomix (manufactured by Hosokawa Micron Corporation); screw-pin mixer (manufactured by Pacific Machinery & Engineering Co., Ltd.); and Loedige mixer (manufactured by Matsubo Corporation).

[0075] Examples of hot mixing mills include the following: KRC mixing mill (manufactured by Kurimoto, Ltd.); Buss Ko-Kneader (manufactured by Buss); TEM type extruder (manufactured by Toshiba Machine Co., Ltd.); TEX twin-screw mixing mill (manufactured by The Japan Steel Works, Ltd.); PCM mixing mill (manufactured by Ikegai Ironworks Corp.); three-roll mill, mixing roller mill, and mixing mill (manufactured by Inoue Mfg., Inc.); KNEADEX (manufactured by Mitsui Mining Co., Ltd.); MS type pressure mixing mill and KNEADER-RUDER (manufactured by Moriyama Company Ltd.); and Banbury mixer (manufactured by Kobe Steel, Ltd.).

[0076] Examples of pulverizers include the following: convection jet mills, Micron jet mills and Inomizers (manufactured by Hosokawa Micron Corporation); IDS mills and PJM jet mills (manufactured by Nippon Pneumatic Mfg. Co., Ltd.); Cross jet mills (manufactured by Kurimoto, Ltd.); NSE-ULMAX (manufactured by Nisso Engineering Co., Ltd.); SK Jet-O-Mill (manufactured by Seishin Enterprise Co., Ltd.); Kryptron (manufactured by Kawasaki Heavy Industries, Ltd.); turbo mills (manufactured by Turbo Kogyo Co., Ltd.); and super rotors (manufactured by Nisshin Engineering Inc.).

[0077] Examples of classifiers include the following: Classiel, Micron, and Spedic classifiers (manufactured by Seishin Enterprise Co., Ltd.); turbine classifiers (manufactured by Nisshin Engineering Inc.); Micron separators, Turboprex (ATP), and TSP separators (manufactured by Hosokawa Micron Corporation); curved injectors (manufactured by Nittetsu Mining Co., Ltd.); dispersion separators (manufactured by Nippon Pneumatic Mfg. Co., Ltd.); and YM Microcut (manufactured by Yasukawa Shoji KK).

[0078] In addition, the following screening machines can be used to screen out coarse particles: Ultra Sonic (manufactured by Koei Sangyo Co., Ltd.); Rezona Sieve and Gyro Sifter (manufactured by Tokuju Corporation); Vibrasonic system (manufactured by Dalton Co., Ltd.); Sonicreen (manufactured by Shinto Kogyo KK); Turbo Screener (manufactured by Turbo Kogyo Co., Ltd.); Microsifter (manufactured by Makino Mfg. Co., Ltd.); or circular vibrating screen.

[0079] The surfaces of the resulting toner base particles can be subjected to an adhesion step that allows inorganic particles to adhere to the surface, and a hot air surface treatment step. There are no particular limitations on the method used in the adhesion step to allow the inorganic particles to adhere to the surface of each toner base particle, and the toner base particles and inorganic particles are weighed in predetermined amounts and then blended. Examples of mixing equipment include a double cone mixer, a V-type mixer, a drum mixer, a super mixer, a Henschel mixer, or a Nottingham mixer, with each mixer being preferred.

[0080] For mixing conditions, a higher rotational speed of the mixing blades and a longer mixing time are preferred because it facilitates the uniform adhesion of boron nitride particles to the surface of each toner base particle. However, when the rotational 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 becomes higher, and the toner can reach a melting point. Therefore, it is preferable, for example, to actively cool the mixer by providing a water-cooling jacket to the mixing blades or the mixer.

[0081] Preferably, the rotational speed of the mixing blades and the mixing time are adjusted to a range where the temperature inside the mixer reaches below 45°C. Specifically, the maximum circumferential speed of the mixing blades is preferably between 10.0 m / s and 150.0 m / s, and the mixing time is preferably adjusted to a range of 0.5 minutes to 60 minutes.

[0082] Furthermore, the attachment step can be carried out in a single stage or in multiple stages, such as two or more stages, and the mixing equipment, mixing conditions, and blending of the toner base particles used in each stage can be the same as or different from those in any other stage.

[0083] Next, the apparatus including the following units can be used as an apparatus for surface treatment of toner base particles: a unit that molten the surface of each toner base particle before treatment with hot air, and a unit that can cool the toner particles treated with hot air with cold air.

[0084] As such devices, examples include, for instance, the Meteorainbow MR type (manufactured by Nippon Pneumatic Mfg. Co., Ltd.).

[0085] One aspect of surface treatment methods using hot air is referenced. Figure 2 This disclosure is limited to the description provided. Figure 2 Example of a cross-section of the surface treatment apparatus used in this disclosure. Specifically, as a surface treatment method, a raw material is prepared by pre-attaching organosilicon polymer particles to the surface of each toner base particle, and the raw material is supplied to the surface treatment apparatus.

[0086] Then, the surface-treated toner particles 114 supplied from the toner particle supply port 100 are accelerated by injection gas ejected from the high-pressure air supply nozzle 115 and directed towards the downward airflow jet member 102.

[0087] Diffusion gas is injected from the airflow injection member 102, and toner particles 114 are diffused outward by the diffusion gas. In this case, the diffusion state of the toner particles can be controlled by adjusting the flow rate of the injection gas and the flow rate of the diffusion gas.

[0088] In addition, to prevent the toner particles from melting, cooling jackets 106 are respectively provided on the outer periphery of the toner particle supply port 100, the outer periphery of the surface treatment equipment, and the outer periphery of the delivery pipe 116.

[0089] Preferably, cooling water (preferably an antifreeze, such as ethylene glycol) is passed through a cooling jacket.

[0090] At the same time, the surface of each toner particle diffused by the diffusion gas is treated with hot air supplied from the hot air supply port 101.

[0091] In this case, the exhaust temperature of the hot air is equal to or higher than the softening point of the toner, preferably 120°C or higher and 300°C or lower, more preferably 150°C or higher and 250°C or lower.

[0092] When the temperature of the hot air is equal to or greater than the softening point of the toner, the binder resin melts, resulting in the silicone polymer particles being fixed to the toner base particles.

[0093] When the exhaust temperature of the hot air exceeds 300°C, the melting state of the toner particles progresses excessively, and particle agglomeration easily occurs during production. As a result, roughening of the toner particles and severe adhesion of the toner particles to the inner wall surface of the equipment occur.

[0094] The toner particles with surfaces treated with hot air are cooled by cold air supplied from a cold air supply port 103 formed on the outer periphery of the upper part of the device. In this case, it is preferable that the cold air is introduced from a second cold air supply port 104 formed on the side of the main body of the device, so as to control the temperature distribution within the device and the surface condition of each toner particle. A slit shape, a louver shape, a perforated plate shape, or a mesh shape may be used for the outlet of the second cold air supply port 104, and the direction horizontal to the center direction or along the wall surface of the device may be selected as the introduction direction depending on the purpose.

[0095] In this case, it is preferable that the airflow of hot air and the airflow of cold air are adjusted to be small so as to ensure a long cross-linking reaction time.

[0096] Furthermore, it is preferable that the cooling air is dehumidified air, because water molecules generated during the cross-linking reaction can be expelled from the system. Specifically, the absolute moisture content of the cooling air is preferably 5 g / m³. 3 The preferred value is 3g / m 3 the following.

[0097] Afterward, the cooled toner particles are drawn in by a hair dryer and collected by a cyclone or the like through a delivery pipe 116.

[0098] [Measuring methods for various physical properties]

[0099] Next, the measurement methods for each physical property will be described.

[0100] Compositional Analysis of Inorganic Oxide Particles

[0101] The inorganic oxide particles introduced into the toner particles of this disclosure refer to the inorganic oxide particles introduced into the toner base particles prior to the following: an attachment step in which the inorganic oxide particles are attached to the surface of each toner base particle before the hot air surface treatment step; and an external addition step. Based on cross-sectional images of the toner particles observed using a transmission electron microscope (TEM), particles with more than 80% of their area present on the inner side of the toner extending more than 100 nm from the outer periphery are used as inorganic oxide particles introduced into the toner particles. Furthermore, energy-dispersive X-ray spectroscopy (EDX) confirms that the particles are formed from at least one element selected from Si, Mg, Al, Ti, and Sr and oxygen, and identifies the composition of each inorganic oxide particle.

[0102] The image of the cross-section of the toner particles obtained by transmission electron microscopy (TEM) is generated as described below.

[0103] An Os film (5 nm) and a naphthalene film (20 nm) were formed on the toner using an osmium plasma coating machine (Filgen, Inc., OPC80T) as protective films. The resulting toner was then embedded in a photocurable resin D800 (JEOL Ltd.). Subsequently, cross-sections of the toner particles, each with a thickness of 60 nm (or 70 nm), were generated using an ultrasonic microtome (Leica, UC7) at a cutting speed of 1 mm / s.

[0104] The obtained cross-sections were observed using the STEM function of a TEM (JEOL Ltd., JEM-2800). Each cross-section was acquired with a STEM probe size of 1 nm and an image size of 1,024 pixels × 1,024 pixels. Among the cross-sections of toner particles, those with a diameter 0.9 to 1.1 times larger than the weight-average particle size of the toner were selected.

[0105] <Measurement of the major diameter, area Sm, and shape factor SF-1 of inorganic oxide particles, and the area St of toner>

[0106] Using the obtained images, the major diameter of each inorganic oxide particle was determined using the image processing software "Image-Pro Plusver. 4.0 (manufactured by Media Cybernetics, Inc.)". In calculating the major diameter, the cross-sections of 100 toner particles were observed, and the average number of their major diameters was used as the major diameter of the inorganic oxide particle. Similarly, the cross-sections of 100 toner particles were observed, and the cross-sectional areas of the toner particles and the areas of the inorganic oxide particles were determined, and their average values ​​were used as the cross-sectional area St of the toner and the area Sm of the inorganic oxide particle, respectively.

[0107] In addition, the shape factor SF-1 of the inorganic oxide particles is determined by the following equation based on the major diameter of the inorganic oxide particles and the area Sm of the inorganic oxide particles calculated above.

[0108] SF-1 = (major diameter of the inorganic oxide particle) 2 / The area of ​​the inorganic oxide particles is Sm×π / 4×100

[0109] SF-1 was calculated from cross-sectional observations of 100 toner particles, and its average value was used as the shape factor SF-1 for inorganic oxide particles.

[0110] <Method for determining the standard deviation of the area Sm of inorganic oxide particles>

[0111] In the cross-sectional images of toner particles observed using the aforementioned transmission electron microscope (TEM), the standard deviation of the area Sm of the inorganic oxide particles in each of the four regions obtained by dividing the cross-section of the toner by the major axis and the perpendicular bisector of the major axis is determined.

[0112] <Measurement of the average roundness of toner>

[0113] The roundness of the toner was measured using a flow particle image analyzer "FPIA-3000" (manufactured by Sysmex Corporation) under measurement and analysis conditions during calibration.

[0114] The "FPIA-3000" flow particle image analyzer (manufactured by Sysmex Corporation) works by capturing images of flowing particles as still images and performing image analysis. A sample added to the sample chamber is supplied to a planar sheath flow cell via a sample aspiration syringe. The sample supplied to the planar sheath flow cell is held by the sheath fluid to form a planar flow.

[0115] Samples passing through a planar sheath flow cell were illuminated with a flash at 1 / 60-second intervals, allowing for the capture of still images of the flowing particles. Furthermore, since the flowing particles form a planar flow, they were photographed in a focused state. Particle images were captured using a CCD camera, and the captured images were processed at an image processing resolution of 512 pixels × 512 pixels (0.37 μm × 0.37 μm per pixel). Then, the contours of each particle image were extracted, and the projected area S and perimeter L of each particle image were measured.

[0116] Next, the equivalent diameter and roundness C are determined using the area S and circumference L. The equivalent diameter is the diameter of a circle having the same area as the projected area of ​​the particle image, and the roundness C is defined as the value obtained by dividing the circumference of the circle determined by the equivalent diameter by the circumference of the particle projected image, and is calculated by the following equation.

[0117] Circularity C = 2 × (π × S) 1 / 2 / L

[0118] When the particle image is circular, the roundness becomes 1.000, and the roundness becomes a smaller value as the unevenness of the outer periphery of the particle image increases. After calculating the roundness of each particle, the roundness range of 0.200 to 1.000 is divided into 800 parts. Then, the arithmetic mean of the obtained roundness is calculated, and its value is used as the average roundness.

[0119] The specific measurement method is as follows. First, place 20 mL of ion-exchanged water, from which solid impurities have been removed, into a glass container. Add 0.2 mL of a diluent prepared by diluting "Contaminon N" (a 10% by mass aqueous solution of a neutral detergent for cleaning precision instruments with a pH of 7, consisting of a nonionic surfactant, anionic surfactant, and an organic detergent, manufactured by Wako Pure Chemical Industries, Ltd.) three times by mass with the ion-exchanged water as a dispersant.

[0120] Further, 0.02 g of the measurement sample was added to the resulting mixture and dispersed using an ultrasonic disperser for 2 minutes to provide a dispersion for measurement. In this case, the dispersion was appropriately cooled so that its temperature reached above 10°C and below 40°C. A benchtop ultrasonic cleaner disperser with an oscillation frequency of 50 kHz and an electrical output of 150 W (e.g., "VS-150" (manufactured by Velvo-Clear Co.)) was used as the ultrasonic disperser. A predetermined amount of ion-exchanged water was placed in a water tank, and 2 mL of Contaminon N was added to the water tank.

[0121] For the measurements, a flow-through particle image analyzer equipped with a standard objective lens (magnification: 10x) was used, and a particle sheath "PSE-900A" (manufactured by Sysmex Corporation) was used as the sheath fluid. The dispersion prepared according to the above procedure was introduced into the flow-through particle image analyzer, and the particle diameter of 3,000 toner particles was measured in both HPF measurement mode and total count mode. Then, the binarization threshold for particle analysis was set to 85%, and the analyzed particle size was limited to a circular equivalent diameter of 1.985 μm or greater and less than 39.69 μm. The average sphericity of the toner particles was then determined.

[0122] Regarding the measurement, automatic focus adjustment is performed before the measurement begins using standard latex granules. For example, "RESEARCH AND TEST PARTICLES LatexMicrosphere Suspensions 5200A" manufactured by Duke Scientific Corporation is diluted with deionized water and used. Afterward, it is preferable to perform focus adjustment every two hours from the start of the measurement.

[0123] In the embodiments of this application, a flow-type particle image analyzer calibrated by Sysmex Corporation and for which a calibration certificate has been issued by Sysmex Corporation was used. Measurements were performed under the measurement and analysis conditions provided with the calibration certificate, except that the particle size analyzed was limited to a circumference equivalent diameter of 1.985 μm or greater and less than 39.69 μm.

[0124] <Observation of the Tips of Inorganic Oxide Particles>

[0125] In observing images of inorganic oxide particles, the angle at the ends was calculated using image processing software "Image-ProPlus ver. 4.0 (manufactured by Media Cybernetics, Inc.)." Specifically, as... Figure 1 The diagram shows that the ends of inorganic oxide particles are detected using the Edge Detector in the aforementioned software.

[0126] Draw a circle with a radius of 200 nm centered on the detected end. Figure 1 Circle 2). Draw the circle connecting the inorganic oxide particles ( Figure 1 The intersection of the contour in section 1) and the two straight lines at the ends are used as the center to draw lines with a width of 50nm. Figure 1In the diagram, two lines extend from the center of circle 2 towards the outline of circle 2. The diagram showing the outline of the inorganic oxide particles included in the two lines, each with a width of 50 nm, is an enlarged view of the line portion. Here, when the outline of the inorganic oxide particles is not included in the 50 nm width, the ends are not analyzed. The angle formed by the two lines, each with a width of 50 nm, is analyzed using the software described above. Figure 1 (3) When the angle is below 90°, it is confirmed that the inorganic oxide particles have sharp points.

[0127] When the cross-section of 100 toner particles is observed, and more than 90% of them are inorganic oxide particles with sharp points, it is confirmed that the inorganic oxide particles introduced into the toner particles each have sharp points.

[0128] <Compositional Analysis of Adhesive Resins>

[0129] Separation methods for adhesive resins

[0130] 100 mg of toner was dissolved in 3 ml of chloroform. Then, the insoluble fraction was removed by aspiration filtration using a syringe fitted with a sample preparation filter (pore size ≥ 0.2 μm and ≤ 0.5 μm, e.g., Myshoridisk H-25-2 (manufactured by Tosoh Corporation)). The soluble fraction was introduced into a preparative HPLC system (equipment: LC-9130NEXT, preparative column [60 cm], manufactured by Japan Analytical Industry Co., Ltd., exclusion limits: 20,000 and 70,000, two connected columns) and supplied with chloroform eluent. The retention time of monodisperse polystyrene standards with a molecular weight of ≥ 2,000 was sorted when peaks were identified from the resulting chromatogram. The resulting fraction solution was dried and solidified to provide a binder resin.

[0131] • Composition identification and mass ratio measurement of adhesive resins using nuclear magnetic resonance spectroscopy (NMR)

[0132] 1 mL of deuterated chloroform was added to 20 mg of toner, and the NMR spectrum of protons in the dissolved binder resin was measured. The content of monomer units used in the formation of binder resins such as styrene-acrylic resins can be determined by calculating the molar ratio and mass ratio of each monomer from the obtained NMR spectrum. For example, in the case of styrene-acrylic copolymers, the composition ratio and mass ratio can be calculated based on the peaks around 6.5 ppm from styrene monomers and the peaks around 3.5 ppm to 4.0 ppm from acrylic monomers. In addition, in the case of copolymers of polyester resins and styrene-acrylic resins, the content of monomer units of the polyester resin is determined by calculating the molar ratio and mass ratio of the copolymer, together with the peaks from each monomer used in the formation of the polyester resin and the peaks from the styrene-acrylic copolymer.

[0133] NMR equipment: JEOL RESONANCE ECX 500

[0134] Observation nucleus: proton

[0135] Measurement mode: Single pulse

[0136] Reference peak: TMS

[0137] Measurement of weight-average molecular weight (Mw)

[0138] The molecular weight distribution (weight-average molecular weight Mw, number-average molecular weight Mn, and peak molecular weight) of the toner was measured by gel permeation chromatography (GPC) as described below.

[0139] First, the sample was dissolved in tetrahydrofuran (THF) at room temperature for 24 hours. Then, the resulting solution was filtered through a solvent-resistant membrane filter, "Myshoridisk" (manufactured by Tosoh Corporation), with a pore size of 0.2 μm, to provide the sample solution. The sample solution was adjusted so that the concentration of the THF-soluble component was 0.8% by mass. Measurements were performed using the sample solution under the following conditions.

[0140] Equipment: HLC8120GPC (Detector: RI) (Manufactured by Tosoh Corporation)

[0141] • Pillars: 7 pillars for Shodex KF-801, 802, 803, 804, 805, 806 and 807 (manufactured by Showa Denko KK)

[0142] Eluent: Tetrahydrofuran (THF)

[0143] • Flow rate: 1.0 ml / min

[0144] Oven temperature: 40.0℃

[0145] • Sample injection volume: 0.10 ml

[0146] In the calculation of the molecular weight of the sample, a molecular weight correction curve was prepared using standard polystyrene resin (e.g., products available under the trade name "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, or A-500", from Tosoh Corporation).

[0147] <Measurement of the coverage rate of external additives>

[0148] The surface of the toner particles was photographed using a FE-SEM S-4800 (manufactured by Hitachi, Ltd.) at a magnification of 50,000x. The coverage of the external additive in the observed images was calculated using the image processing software "ImageJ" as described below. Particle analysis was performed to select particles originating from the external additive in the image using the software. Next, the area of ​​the selected image was represented by a measurement setting. This value was divided by the area of ​​the entire field of view to provide the coverage of the external additive in that view.

[0149] The conditions for taking images with the S-4800 are as follows.

[0150] (1) Sample preparation

[0151] A thin layer of conductive paste is applied to the sample stage (aluminum sample stage: 15mm × 6mm), and toner is sprayed onto the conductive paste. Further, air is blown to remove excess toner from the sample stage, thereby thoroughly drying the sample stage. The sample stage is placed in the sample holder, and its height is adjusted to 36mm using a sample height gauge.

[0152] (2) S-4800 observation condition settings

[0153] Inject liquid nitrogen into the contamination trap of the S-4800 housing until it overflows, and allow the sample to stand for 30 minutes. Start the S-4800's "PC-SEM" to perform a rinse (cleaning of the FE chip as the electron source). Click the acceleration voltage display on the control panel and press the [Rinse] button to open the rinse execution dialog box. Confirm the rinse intensity is 2 and proceed with the rinse. Confirm the emission current generated by the rinse is 20 μA to 40 μA. Insert the sample holder into the sample chamber of the S-4800 housing. Press the [Origin] button on the control panel to move the sample holder to the observation position.

[0154] Click the accelerating voltage display section to open the HV settings dialog box. Set the accelerating voltage to [1.1kV] and the emission current to [20μA]. In the [Basic] option 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 set the observation mode for the backscattered electron image. Similarly, in the [Basic] option of the operation panel, set the probe current in the photoelectric system condition block to [Normal], set the focus mode to [UHR], and set WD to [4.5mm]. Press the [ON] button on the accelerating voltage display section of the control panel to apply the accelerating voltage.

[0155] (3) Calculation of the number-average particle size (D1) of the toner

[0156] Drag within the magnified display section of the control panel to set the magnification to 5,000 (5k). Rotate the focus knob [Coarse] on the operation panel, and adjust the aperture for alignment once focus is achieved to a certain extent. Click [Align] on the control panel to display the alignment dialog box, and select [Beam]. Rotate the STIGMA / ALIGNMENT knob (X,Y) on the operation panel to move the displayed beam to the center of the concentric circles. Next, select [Aperture], and gradually rotate the STIGMA / ALIGNMENT knob (X,Y) to adjust so that the image movement can be stopped or minimized. Close the aperture dialog box and focus the image using autofocus. Repeat this operation twice more to refocus the image.

[0157] (4) Focus adjustment

[0158] Regarding the toner particles obtained in project (3) with a number average particle size (D1) ± 0.1 μm, with the midpoint of the largest diameter aligned with the center of the measurement screen, the magnification is set to 10,000 (10k) times by dragging within the magnified display section of the control panel.

[0159] Rotate the focus knob on the control panel to [Coarse], and once focus is achieved to a certain extent, adjust the aperture for alignment. Click [Align] on the control panel to display the alignment dialog box, 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 circles.

[0160] Next, select [Aperture] and gradually rotate the STIGMA / ALIGNMENT knob (X, Y) to adjust so that image movement can be stopped or minimized. Close the aperture dialog box and focus the image using autofocus. Then, set the magnification to 50,000 (50k) and focus in the same way as above using the focus knob and STIGMA / ALIGNMENT knob, and focus the image again using autofocus. Repeat this operation to focus the image. Here, when the tilt angle of the observation surface is large, the accuracy of the coverage measurement becomes prone to decrease. Therefore, when focusing, select adjustment so that the entire observation surface can be focused simultaneously, and then select and analyze the observation surface with the smallest tilt.

[0161] (5) Image saving

[0162] Brightness was adjusted using ABC mode, and a 640-pixel × 480-pixel photo was taken and saved. The following analysis is performed using this image file. One photo was taken for each toner particle, and images were obtained for 25 toner particles.

[0163] <Measurement of Particle Size of Toner>

[0164] A precision particle size distribution measurement device based on pore resistance (trade name: Coulter CounterMultisizer) and dedicated software (trade name: Beckman Coulter Multisizer 3Version 3.51, manufactured by Beckman Coulter, Inc.) were used. Measurements were performed using a pore size of 100 μm and with 25,000 effective measurement channels, followed by analysis of the measurement data to calculate the particle size. An electrolyte aqueous solution prepared by dissolving premium sodium chloride in ion-exchanged water to a concentration of approximately 1% by mass, for example, ISOTON II (trade name) manufactured by Beckman Coulter, Inc., can be used for measurement. The dedicated software was set up as described below before measurement and analysis.

[0165] In the "Change Standard Operating Method (SOM)" screen of the dedicated software, set the total count for the control mode to 50,000 particles, the number of measurements to 1, and set the value obtained using "standard particles with a respective particle size of 10.0 μm" (manufactured by Beckman Coulter, Inc.) as the Kd value. Automatically set the threshold and noise level by pressing the "Threshold / Measurement Noise Level" button. Additionally, set the current to 1,600 μA, the gain to 2, and the electrolyte to ISOTON II (trade name), and check the "Rinse the port after each measurement" checkbox.

[0166] In the "Convert Pulse to Size Setting" screen of the dedicated software, set the element spacing to logarithmic particle size, the number of particle size elements to 256, and the particle size range to a range of 2μm or more and 60μm or less.

[0167] The specific measurement method is as follows.

[0168] (1) Pour approximately 200 mL of electrolyte solution into a 250 mL round-bottom glass beaker specifically designed for Multisizer 3. Place the beaker on the sample stage and stir the electrolyte solution in the beaker counterclockwise at 24 rpm using a stir bar. Then, remove contaminants and air bubbles from the beaker using the "Flush" function of the analysis software.

[0169] (2) Pour about 30 mL of the electrolyte solution into a 100 mL flat-bottomed glass beaker. Add about 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 instruments, manufactured by Wako Pure Chemical Industries, Ltd.) three times by weight with ion-exchanged water to the electrolyte solution.

[0170] (3) Prepare an ultrasonic dispersion unit (trade name: Ultrasonic Dispersion System Tetra 150, manufactured by Nikkaki Bios Co., Ltd.) with two oscillators, each with an oscillation frequency of 50kHz, configured with a phase offset of 180° and a power output of 120W. Add a predetermined amount of ion-exchanged water and about 2 mL of Contaminon N (trade name) to the water tank of the ultrasonic dispersion unit.

[0171] (4) Place the beaker from item (2) in the beaker fixing hole of the ultrasonic dispersion unit and operate the ultrasonic dispersion unit. Then, adjust the height of the beaker so that the liquid level of the electrolyte solution in the beaker can resonate with the ultrasonic waves from the ultrasonic dispersion unit to the maximum possible extent.

[0172] (5) While the electrolyte solution is being ultrasonically irradiated, approximately 10 mg of toner (granules) is gradually added to and dispersed in the electrolyte solution in the beaker in item (4). Then, the ultrasonic dispersion treatment is continued for another 60 seconds. During ultrasonic dispersion, the water temperature in the water tank is appropriately adjusted to be above 10°C and below 40°C.

[0173] (6) Add the electrolyte aqueous solution containing the dispersible toner (particles) from item (5) dropwise into the round-bottom flask from item (1) placed in the sample rack using a pipette, and adjust the measurement concentration to about 5%. Then, perform measurements until the particle size of 50,000 particles is measured.

[0174] (7) Analyze the measurement data using the dedicated software provided with the equipment, and calculate the weight-average particle size (D4). When the dedicated software is set to display a graph in volume % units, the "Average Diameter" on the "Analysis / Volume Statistics (Arithmetic Mean)" screen of the dedicated software is the weight-average particle size (D4). When the dedicated software is set to display a graph in number % units, the "Average Diameter" on the "Analysis / Number Statistics (Arithmetic Mean)" screen is the number-average particle size (D1).

[0175] [Example]

[0176] The present disclosure is described in more detail below with reference to production examples and embodiments. However, the present disclosure is by no means limited thereto. All parts in the following blends refer to "parts by weight".

[0177] <Production Example of Inorganic Oxide Particles 1>

[0178] A mixture of argon and oxygen in a volume ratio of 3:1 was introduced into the reaction vessel to replace the atmosphere. Oxygen was then introduced into the reaction vessel at a rate of 40 (m³ / s). 3 / hr) supply and hydrogen at 20 (m 3 The feed is supplied at a pressure of 147 kPa (1.5 kg / cm³), followed by the use of an igniter to create a combustion flame from oxygen and hydrogen. Then, the silicon powder used as raw material is subjected to a pressure of 147 kPa (1.5 kg / cm³). 2 Hydrogen carrier gas is introduced into a combustion flame to form a dust cloud. The dust cloud is ignited by the combustion flame, causing an oxidation reaction caused by a dust explosion. After the oxidation reaction, the interior of the reaction vessel is cooled to obtain inorganic oxide particles with a number average particle size of 2.68 μm (2,680 nm).

[0179] <Production Examples of Inorganic Oxide Particles 2-4, 6, 7, and 12>

[0180] Inorganic oxide particles 1 were pulverized using a pulverizer (manufactured by Hosokawa Micron Corporation) while adjusting the pulverizer's rotation speed, sieve size, and number of passes. As a result, inorganic oxide particles 2 with a number-average particle size of 1.54 μm (1,540 nm) were obtained. Furthermore, inorganic oxide particles 1 were pulverized using the same pulverizer while adjusting the pulverizer's rotation speed, sieve size, and number of passes. Inorganic oxide particles 3, 4, 6, 7, and 12 were obtained. The number-average particle sizes of the obtained inorganic oxide particles are shown in Table 1.

[0181] <Production Example of Inorganic Oxide Particles 5>

[0182] A mixture of argon and oxygen in a volume ratio of 3:1 was introduced into the reaction vessel to replace the atmosphere. Oxygen was then introduced into the reaction vessel at a rate of 40 (m³ / s). 3 / hr) supply and hydrogen at 20 (m 3 A supply of ( / hr) is provided, followed by the use of an igniter to create a combustion flame composed of oxygen and hydrogen. Then, the metallic silicon powder used as raw material is subjected to a pressure of 0.5 kg / cm². 3 Hydrogen carrier gas is introduced into the combustion flame to form a dust cloud. The dust cloud is ignited by the combustion flame, causing an oxidation reaction caused by a dust explosion. After the oxidation reaction, the interior of the reaction vessel is cooled to obtain silica powder with a number average particle size of 3.44 μm.

[0183] While adjusting the pulverizer's rotation speed, sieve size, and number of passes, the silica powder was pulverized using the pulverizer. Thus, silica particles 5 were obtained. The number-average particle size of the obtained inorganic oxide particles is shown in Table 1.

[0184] <Production Example of Inorganic Oxide Particles 8>

[0185] Ilmenite ore was dried, pulverized, and treated with concentrated sulfuric acid for digestion / extraction. After removing unreacted ore, ferric sulfate was decrystalline. An aqueous sodium hydroxide solution was added to the resulting titanium oxysulfate to adjust its pH to 9.0, followed by desulfurization. The result was then neutralized with hydrochloric acid to pH 5.8, filtered, and washed with water. After calcination in a furnace, the result was pulverized using a pulverizer while adjusting the pulverizer speed, sieve size, and number of passes. Thus, titanium oxide as inorganic oxide particles 8 was obtained. The number-average particle size of the obtained inorganic oxide particles is shown in Table 1.

[0186] <Production Example of Inorganic Oxide Particles 9>

[0187] Magnesium oxide powder (PYROKISUMA 3320, manufactured by Kyowa Chemical Industry Co., Ltd.) was pulverized using a pulverizer while adjusting the pulverizer's rotation speed, sieve size, and number of passes. Magnesium oxide particles, known as inorganic oxide particles 9, were thus obtained. The number-average particle size of the obtained inorganic oxide particles is shown in Table 1.

[0188] <Production Example of Inorganic Oxide Particles 10>

[0189] Alumina was refined using bauxite as a raw material via the Bayer process. Sodium hydroxide was added to the bauxite and dissolved therein by heating at 250°C. After the insoluble components were removed by filtration, the aluminum hydroxide was collected as a solid by cooling. This aluminum hydroxide was then heated and dehydrated at 1,050°C to provide alumina. Next, the result was pulverized using a pulverizer while adjusting the pulverizer speed, sieve size, and number of passes. Thus, alumina particles as inorganic oxide particles 10 were obtained. The number average particle size of the obtained inorganic oxide particles is shown in Table 1.

[0190] <Production Example of Inorganic Oxide Particles 11>

[0191] Ilmenite ore was dried, pulverized, and treated with concentrated sulfuric acid for decomposition / extraction. After removing unreacted ore, ferric sulfate was decrystalline. An aqueous sodium hydroxide solution was added to the resulting titanium oxysulfate to adjust its pH to 9.0, followed by desulfurization. The resulting product was then neutralized with hydrochloric acid to pH 5.8, filtered, and washed with water. Water was added to the washed filter cake to form a 1.5 mol / L slurry as TiO2, and hydrochloric acid was added to the slurry to adjust its pH to 1.5, causing deflocculation. The desulfurized and deflocculated metatitanic acid was collected as TiO2 and placed in a 3L reaction vessel. An aqueous strontium chloride solution was added to the deflocculated metatitanic acid slurry to bring the SrO / TiO2 molar ratio to 1.18, and the TiO2 concentration was adjusted to 0.9 mol / L.

[0192] Next, the obtained product was heated to 90°C under stirring and mixing. Then, 444 mL of a 10N sodium hydroxide aqueous solution was added to the product over 50 minutes, while microbubbling of nitrogen was carried out at 600 mL / min. Afterward, stirring was performed at 95°C for 1 hour, while microbubbling of nitrogen was carried out at 400 mL / min. The reaction slurry was then rapidly cooled to 12°C under stirring, while cooling water at 10°C was introduced into the jacket of the reaction vessel. The slurry was neutralized by adding hydrochloric acid and stirred for 1 hour, followed by filtration and separation. After calcination in a furnace, the product was pulverized using a pulverizer while adjusting the pulverizer speed, sieve size, and number of passes. Thus, strontium titanate was obtained as inorganic oxide particles 11. The number-average particle size of the obtained inorganic oxide particles is shown in Table 1.

[0193] Table 1

[0194]

[0195] <Production Example of Toner 1>

[0196] • Adhesive Resin A: 80.0 parts

[0197] (Styrene-acrylic resin with a mass ratio of styrene to n-butyl acrylate of 78:22; Mw = 180,000, Tg = 58℃)

[0198] • Adhesive resin B: 20.0 parts

[0199] (Styrene-acrylic resin with a styrene-to-butyl acrylate mass ratio of 78:22; Mw = 5,300, Tg = 58℃)

[0200] • Paraffin wax (HNP-9, Nippon Seiro Co., Ltd.): 5.0 parts

[0201] Inorganic oxide particles 2: 2.0 parts

[0202] ·Aluminum 3,5-di-tert-butylsalicylate compound: 0.5 parts

[0203] • Carbon black: 5.0 parts

[0204] The above materials were mixed using a Henschel mixer (model FM-75, manufactured by Mitsui Mining Co., Ltd.) at 20 revolutions per second. -1 The mixture was stirred for 5 minutes and then kneaded using a twin-screw mixer (model PCM-30, manufactured by Ikegai Corp.) set at 130°C. The resulting mixture was cooled to 25°C and coarsely pulverized to below 1 mm 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 resulting material was classified using a multi-stage classifier utilizing the wall adhesion effect to obtain toner base particles 1 with a weight average particle size (D4) of 9.0 μm.

[0205] 2.0 parts of hydrophobic silica fine particles (surface treated with 15% hexamethyldisilazane, primary particle number average size: 50 nm) were added to 100 parts of the obtained toner base particles 1, and the particles were mixed using a Henschel mixer (model FM-75, manufactured by Mitsui Mining Co., Ltd.) at 30 rpm. -1 Mixed with a rotation time of 10 minutes, this allows the inorganic particles to adhere to the surface of each toner base particle.

[0206] Next, use Figure 2 The surface treatment equipment shown in the diagram uses hot air for processing. The surface treatment is carried out under the following conditions used in surface modification: raw material feed rate of 1.0 kg / hr and hot air flow rate of 1.4 m / s.3 / min, hot air exhaust temperature is 180℃, cold air temperature is 3℃, and cold air flow rate is 1.2m. 3 / min, and absolute moisture content is 3.0 g / m 3 .

[0207] Next, the fine and coarse powders are simultaneously classified and removed using an air classifier ("Elbow-Jet Labo EJ-L-3", manufactured by Nittetsu Mining Co., Ltd.) that utilizes the wall effect to obtain toner particles 1.

[0208] Next, 100.0 parts of toner granules 1 and 2.0 parts of hydrophobic silica fine particles (RY200 silica particles, manufactured by Nippon Aerosil Co., Ltd.) were loaded into a Henschel mixer (model FM-75, manufactured by Mitsui MiikeKakoki KK). Mixing was performed at 30°C by setting the circumferential speed of the rotating blades to 35 m / sec and the mixing time to 8 minutes. Toner 1 was thus obtained using a sieve with an aperture of 45 μm. The formulation of toner 1 is shown in Table 2, and its physical properties are shown in Table 3.

[0209] <Production examples of colorants 2, 5-10 and 15-18>

[0210] Except for using the inorganic oxide particles shown in Table 2, toners 2, 5-10, and 15-18 are obtained in the same manner as in the production example of toner 1. The formulations of toners 2, 5-10, and 15-18 are shown in Table 2, and their physical properties are shown in Table 3.

[0211] <Production Example of Toner 3>

[0212] Except that the hot air exhaust temperature during hot air surface treatment of the toner particles, each with inorganic particles adhering to its surface, is changed to 120°C, toner 3 is obtained in the same manner as in the production example of toner 1. The formulation of toner 3 is shown in Table 2, and its physical properties are shown in Table 3.

[0213] <Production Example of Toner 4>

[0214] Except that the hot air exhaust temperature during hot air surface treatment of the toner particles, each with inorganic particles adhering to its surface, is changed to 100°C, toner 4 is obtained in the same manner as in the production example of toner 1. The formulation of toner 4 is shown in Table 2, and its physical properties are shown in Table 3.

[0215] <Production Examples of Toners 11 and 12>

[0216] Except for the amount of external additives added, as shown in Table 2, toners 11 and 12 are obtained in the same manner as in the production example of toner 1. The formulations of toners 11 and 12 are shown in Table 2, and their physical properties are shown in Table 3.

[0217] <Production Example of Toner 13>

[0218] Except that the binder resin is changed to 100.0 parts of binder resin C ([polyoxypropylene (2,2)-2,2-bis(4-hydroxyphenyl)propane:polyoxyethylene (2,2)-2,2-bis(4-hydroxyphenyl)propane:terephthalic acid:trimethicone = 80:20:85:15]) as shown in Table 2, toner 13 is obtained in the same manner as in the production example of toner 1. The formulation of toner 13 is shown in Table 2, and its physical properties are shown in Table 3.

[0219] <Production Example of Toner 14>

[0220] Except that the binder resin is changed to 100.0 parts of binder resin A as shown in Table 2, toner 14 is obtained in the same manner as in the production example of toner 1. The formulation of toner 14 is shown in Table 2, and its physical properties are shown in Table 3.

[0221] <Production Examples of Toners 19 and 20>

[0222] Except for using the inorganic oxide particles shown in Table 2, toners 19 and 20 are obtained in the same manner as in the production example of toner 1. The formulations of toners 19 and 20 are shown in Table 2, and their physical properties are shown in Table 3.

[0223] <Production Example of Toner 21>

[0224] 100.0 parts of toner base particles 1 and 2.0 parts of hydrophobic silica fine particles (silica particles RY 200, manufactured by Nippon Aerosil Co., Ltd.) obtained in the toner 1 production example were loaded into a Henschel mixer (model FM-75, manufactured by Mitsui Miike Kakoki KK). Mixing was performed at 30°C by setting the circumferential speed of the rotating blades to 35 m / sec and the mixing time to 8 minutes. Toner 21 was thus obtained using a sieve with an aperture of 45 μm.

[0225] The formulation of colorant 21 is shown in Table 2, and its physical properties are shown in Table 3.

[0226] Table 2

[0227]

[0228] Table 3

[0229]

[0230] [Examples 1-18 and Comparative Examples 1-3]

[0231] The evaluation tests for toners 1-18 in the examples and toners 19-21 in the comparative examples were each conducted in the following manner.

[0232] <Evaluation of Transferability>

[0233] The toner was loaded into a cartridge (CF230X) of a printer (LaserJet Pro m203dw) manufactured by Hewlett-Packard Company that uses a cleaner-free system, and its transferability was evaluated under low temperature and low humidity conditions (15.0°C, 10.0% RH).

[0234] When a solid image is formed at a transfer current of 8.0 μA, a transparent pressure-sensitive adhesive tape made of polyester (trade name: Polyester Tape No. 5511, supplied by Nichiban Co., Ltd.) is applied to the residual toner on the electrostatic latent image carrier (photosensitive component); and then the pressure-sensitive adhesive tape is peeled off. For each toner, the concentration difference is calculated by subtracting the concentration obtained when only the pressure-sensitive adhesive tape is applied to the paper from the concentration obtained when only the pressure-sensitive adhesive tape is applied to the paper.

[0235] Concentration was measured using a REFLECTOMETER MODEL TC-6DS manufactured by Tokyo Denshoku Co., Ltd. A green filter was used as the filter.

[0236] Evaluations will be conducted at the following times: the initial stage; after 3,500 images; and after 7,000 images.

[0237] The judgment criteria are as follows. Grade C and above are considered satisfactory. The results are shown in Table 4.

[0238] A: A concentration difference of less than 5.0 is very satisfactory.

[0239] B: A concentration difference of 5.0 or higher and less than 10.0 is satisfactory.

[0240] C: The concentration difference is greater than 10.0 and less than 15.0.

[0241] D: Concentration difference is 15.0 or higher.

[0242] <Evaluation of Cleanliness>

[0243] Cleanliness was evaluated in the same manner as in the transferability evaluation, under low temperature and low humidity conditions (15.0°C, 10.0% RH) by filling the toner cartridge (CF230X) of a printer (LaserJet Pro m203dw) manufactured by Hewlett-Packard Company.

[0244] Print as Figure 3 The image shown includes a block-shaped solid black image from the first cycle of the developing sleeve and a halftone full solid image formed beneath the solid black image. The images are then visually evaluated to determine how much of the image history from the first cycle of the developing sleeve appears in the halftone image after the second cycle of the developing sleeve.

[0245] Evaluations will be conducted at the following times: after 2,000 images; after 3,500 images; and after 7,000 images.

[0246] The judgment criteria are as follows. Grade C and above are considered satisfactory. The results are shown in Table 4.

[0247] A: No concentration difference was observed.

[0248] B: A slight concentration difference was observed.

[0249] C: A concentration difference was observed.

[0250] D: Even after the third week of development, a concentration difference was observed.

[0251] In a cleaner-less system, as illustrated in the diagram, the printer's processing box... Figure 4 During the process, all the toner remaining on the photosensitive drum 11 that was not transferred to the paper reaches the charging roller 12 due to the absence of a cleaning component for the photosensitive element. Most of the toner remaining on the photosensitive drum 11 becomes negatively charged through friction against the charging roller 12 and is collected by the developing sleeve 21 without adhering to the charging roller 12. However, when contamination of the charging roller develops in the latter half of the durability process, the transferred residual toner reaching the charging roller is not sufficiently negatively charged. In addition, the charge difference between the photosensitive element and the developing sleeve becomes difficult to induce. As a result, the transferred residual toner cannot be collected by the developing sleeve and appears as a ghost image after the second cycle of the developing sleeve.

[0252] Furthermore, the inventors envision that, by using the toner disclosed herein which has suppressed rolling, even in the latter part of the durability process where, as described above, it is difficult to collect the toner from the developing sleeve, and in a cleaner-free system, residual toner from the transfer can also be collected by the developing sleeve, and a satisfactory image can be obtained.

[0253] Table 4

[0254]

[0255] According to this disclosure, as the speed of electrophotographic equipment increases and its lifespan is extended, the transferability and cleanliness of toners can be achieved at a high level simultaneously.

[0256] While this disclosure has been described with reference to exemplary embodiments, it should be understood that this disclosure is not limited to the exemplary embodiments disclosed. The scope of the appended claims should be interpreted in the broadest possible sense to cover all such variations and equivalent structures and functions.

Claims

1. A toner, characterized in that, It includes: Toner particles containing binder resin and inorganic oxide particles, The inorganic oxide particles are particles containing oxides of at least one element selected from the group consisting of Si, Mg, Al, Ti, and Sr. Specifically, when observing the cross-section of the toner using a transmission electron microscope, if the area of ​​the inorganic oxide particles is represented by Sm and the cross-sectional area of ​​the toner is represented by St, then Sm / St is 4.0% or higher. In the cross-sectional observation, the standard deviation of the area Sm of the inorganic oxide particles occupying each of the four regions obtained by dividing the cross-section of the toner by the major axis and the perpendicular bisector of the major axis is greater than 0.

40. The average roundness of the toner is greater than 0.

950.

2. The toner according to claim 1, wherein, in the cross-sectional observation, the major axis of the inorganic oxide particles is 400–3,000 nm.

3. The toner according to claim 1 or 2, wherein, in the cross-sectional view, the inorganic oxide particles include pointed ends.

4. The toner according to claim 1 or 2, wherein, in the cross-sectional view, the major axis of the inorganic oxide particles is 750 to 3,000 nm.

5. The toner according to claim 1 or 2, wherein, in the cross-sectional observation, the standard deviation of the area Sm of the inorganic oxide particles is 0.50 or more.

6. The toner according to claim 1 or 2, wherein the inorganic oxide particles are silicon dioxide particles.

7. The toner according to claim 1 or 2, wherein, in the cross-sectional view, the shape factor SF-1 of the inorganic oxide particles is 140 or more.

8. The toner according to claim 1 or 2, wherein the average roundness of the toner is 0.960 or higher.

9. The toner according to claim 1 or 2, The toner further includes external additives, and The coverage rate of the external additives is 75% or more.

10. The colorant according to claim 1 or 2, wherein the binder resin is a styrene-acrylic resin.

11. The toner according to claim 1 or 2, The adhesive resin is a styrene-acrylic resin, and In the molecular weight distribution of the tetrahydrofuran-soluble component of the adhesive resin, there are two or more peaks or shoulders in the range of weight-average molecular weight Mw of 3,000 to 2,000,000.

12. A method for producing a colorant, characterized in that, It is used to produce toners that include toner particles containing binder resin and inorganic oxide particles. The production method includes obtaining the colorant particles. Obtaining the toner particles includes obtaining toner particles before hot air surface treatment and performing surface treatment on the toner particles before hot air surface treatment using hot air. Obtaining the toner particles before hot air surface treatment involves melting and mixing the binder resin and the inorganic oxide particles. The inorganic oxide particles are particles containing oxides of at least one element selected from the group consisting of Si, Mg, Al, Ti, and Sr. Specifically, when observing the cross-section of the toner using a transmission electron microscope, if the area of ​​the inorganic oxide particles is represented by Sm and the cross-sectional area of ​​the toner is represented by St, then Sm / St is 4.0% or higher. In the cross-sectional observation, the standard deviation of the area Sm of the inorganic oxide particles occupying each of the four regions obtained by dividing the cross-section of the toner by the major axis and the perpendicular bisector of the major axis is greater than 0.

40. The average roundness of the toner is greater than 0.

950.

13. The method for producing a toner according to claim 12, wherein, in the cross-sectional view, the inorganic oxide particles include pointed ends.

14. The method for producing a toner according to claim 12 or 13, wherein, in the cross-sectional view, the shape factor SF-1 of the inorganic oxide particles is 140 or more.

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