Toner

Abstract

To provide a toner that has improved releasability, while maintaining high durability and low temperature fixability.SOLUTION: A toner has a toner particle having a toner core particle and a shell that covers the toner core particle. The shell includes an organic silicon polymer. The shell includes domains of a mold release agent. In cross-sectional observation of the toner particle by a transmission electron microscope, in the total number of the domains of the mold release agent to be observed, the ratio of the domains of the mold release agent not in contact with the toner core particles is 85 number% or more.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This disclosure relates to a toner for developing electrostatic images (electrostatic latent images) used in image formation methods such as electrophotography and electrostatic printing. [Background technology]

[0002] In recent years, there has been a demand for longer lifespans in image forming equipment such as photocopiers, printers, and fax machines. To meet this demand, improved long-term durability of toner is required. However, deformation of the toner due to long-term durability reduces its fluidity, leading to contamination of the developing material, such as fusion. Therefore, there is a need for toner that is less prone to deformation even with long-term durability.

[0003] Conventionally, from the perspective of long-term durability of toner, toners with a core-shell structure in which the toner surface is covered with a high-strength resin have been proposed. For example, Patent Document 1 proposes a toner having a shell composed of an organosilicon polymer. On the other hand, Patent Document 2 proposes a toner having a shell that achieves both durability and low-temperature fixability. The toner described in Patent Document 2 proposes toner particles in which thermoplastic resin domains are attached to the core and then a shell is formed. Since the thermoplastic resin domains are in contact with the core, the thermoplastic resin domains act as plasticizers on the core during fixation, achieving both high durability and low-temperature fixability. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2014-130242 [Patent Document 2] Japanese Patent Publication No. 2019-056897 [Overview of the project] [Problems that the invention aims to solve]

[0005] Organosilicon polymers, such as those described in Patent Document 1, form a strong three-dimensional crosslinked structure through siloxane bonds with high bonding energy, resulting in a shell with high strength. Therefore, covering the toner surface with an organosilicon polymer suppresses toner deformation and solves material contamination. However, because the toner particles are covered with a strong shell derived from the organosilicon polymer, their adhesion and release properties are reduced. Furthermore, in toners with high-strength shells, as described in Patent Documents 1 and 2, low-temperature fixing inhibits the release agent from the core during fixing, resulting in reduced release properties. Consequently, sufficient release effect cannot be obtained, and there is room for improvement in release properties. Another example of achieving low-temperature fixing properties is lowering the glass transition temperature (Tg) of the core particles, but in the case of high-strength shells, the release agent still becomes less likely to seep out during low-temperature fixing. This disclosure provides a toner that improves release properties while maintaining high durability and low-temperature fixability. [Means for solving the problem]

[0006] This disclosure relates to a toner having toner core particles and toner particles having a shell covering the toner core particles, The shell contains an organosilicon polymer, The shell contains domains of the release agent, In cross-sectional observation of the toner particles using a transmission electron microscope, the release agent is observed. This relates to toner in which the proportion of domains of the release agent that are not in contact with the toner core particles out of the total number of particles is 85% or more. [Effects of the Invention]

[0007] According to this disclosure, it is possible to provide a toner that improves release properties while maintaining high durability and low-temperature fixability. [Modes for carrying out the invention]

[0008] In this disclosure, descriptions of numerical ranges such as "XX or greater and YY or less" or "XX to YY" mean a numerical range that includes the lower and upper limits, unless otherwise specified. When numerical ranges are described in steps, the upper and lower limits of each numerical range can be combined in any way.

[0009] This disclosure relates to a toner having toner core particles and toner particles having a shell covering the toner core particles, The shell contains an organosilicon polymer, The shell contains domains of the release agent, This relates to a toner in which, in cross-sectional observation of the toner particles using a transmission electron microscope, the proportion of domains of the release agent that are not in contact with the toner core particles out of the total number of domains of the release agent observed is 85 percent or more.

[0010] The statement that a shell contains a release agent domain (hereinafter also referred to as the "release agent domain") means that the release agent domain is enclosed in the shell material and localized within the shell. The release agent domain does not necessarily have to be completely covered by the shell; a portion of the release agent domain may be exposed on the toner particle surface to an extent that does not impair the effects of this disclosure. Here, the release agent domain may or may not be in contact with the toner core particles, but it is preferable that the release agent domain is not in contact with the toner core particles. When the release agent domain is not in contact with the core, the release agent does not penetrate to the interface between the toner core particles and the shell within the toner particles during fixing, and as a result it is more likely to seep out to the outside of the toner particles, the release properties are improved.

[0011] In particular, when observing the cross-section of toner particles using a transmission electron microscope, it is necessary that the proportion of release agent domains that are not in contact with the toner core particles (hereinafter also referred to as the "non-contact ratio") out of the total number of release agent domains observed be 85 percent or more. In this case, the release agent seeps uniformly onto the surface of the toner particles during fixing, so that a sufficient release effect can be exerted relative to the amount of release agent contained in the toner particles. The non-contact ratio is preferably 90 to 100% by number, more preferably 95 to 100% by number, and even more preferably 98 to 100% by number. The non-contact ratio can be increased by previously coating the release agent domain with a material containing an organosilicon polymer. Also, the non-contact ratio can be decreased by reducing the coating rate when the release agent domain is previously coated with a material containing an organosilicon polymer.

[0012] As a confirmation that the release agent domain is not in contact with the toner core particles, it can be carried out using silicon mapping by TEM-EDX of the toner particle cross-section. Also, the fact that the release agent domain is encapsulated in the shell can be confirmed by observing the shell containing the organosilicon polymer and the release agent domain by silicon mapping by TEM-EDX of the toner particle cross-section. Further, in combination with silicon mapping, by depth profile analysis using time-of-flight secondary ion mass spectrometry TOF-SIMS, a fragment ion peak corresponding to an aliphatic hydrocarbon chain as in the following formula (1) may be measured and confirmed inside the shell.

Chemical formula

[0013] Also, the shell contains an organosilicon polymer. For example, the shell is an organosilicon polymer that encapsulates the domain of the release agent. By the shell containing the organosilicon polymer, sufficient strength can be maintained even when encapsulating the domain of the release agent, and at the time of fixing, it softens by heat and the encapsulated release agent can quickly bleed out to the outside. From the above, it is considered that by using an organosilicon polymer as the shell having a release agent domain, high durability and sufficient release effect can be imparted to the toner.

[0014] By performing depth profile analysis using time-of-flight secondary ion mass spectrometry (TOF-SIMS) on toner particles, it is preferable that fragment ion peaks corresponding to the structure represented by formula (1) appear in the range of molecular weights of 400 to 600 (more preferably 450 to 550) in the region corresponding to the domain of the release agent. When a release agent having an aliphatic hydrocarbon chain in which fragment ion peaks appear within the above range is used, the release property is improved. The molecular weight of the above fragment ion peak can be controlled by the release agent used.

[0015] Also, in the cross-sectional observation of toner particles by a transmission electron microscope, the average value of the shortest distance D from the surface of the toner particles to the domain of the release agent is preferably 5 to 50 nm. More preferably, it is 10 to 40 nm, and still more preferably, it is 20 to 30 nm. When the average value of D is 5 nm or more, the strength of the shell of the toner particles increases, and the shell is less likely to be crushed. Therefore, the toner particles are less likely to deform, and member contamination can be further suppressed. On the other hand, when the average value of D is 50 nm or less, the release agent is likely to ooze out from the toner particles during fixing, and the release effect is further improved. The average value of D can be controlled by changing the film thickness of the coating when the domain of the release agent is previously coated with a material containing an organosilicon polymer. It can also be controlled by the film thickness of the shell coating the toner particles, the size of the domain of the release agent, and the number thereof.

[0016] Also, in the cross-sectional observation of the toner particles by a transmission electron microscope, the ratio (S2 / S1×100) of the total area S2 of the domain of the release agent to the area S1 occupied by the toner core particles is preferably 0.05 to 5.00 area%. More preferably, it is 0.10 to 4.00 area%, still more preferably, it is 0.20 to 1.00 area%, and even more preferably, it is 0.30 to 0.60 area%. When S2 / S1×100 is 0.05 area % or more, the amount of release agent in the toner particles becomes more appropriate, resulting in improved release effect. Also, when S2 / S1×100 is 5.00 area % or less, the amount of release agent contained in the shell covering the toner particles becomes more appropriate, improving the strength of the shell and making the toner particles less prone to deformation, thus further suppressing contamination of the material. The S2 / S1 × 100 ratio can be controlled by adjusting the amount of release agent used.

[0017] The area percentage (coverage rate) of the organosilicon polymer on the surface of the toner particles is preferably 35 to 75 area%, more preferably 45 to 70 area%, and even more preferably 50 to 65 area%. When the coverage rate is 75% area or less, the proportion of toner core particles on the surface of the toner particles is favorable, so the toner core particles and the image receiving paper fuse well during fixing. Consequently, separation The type is improved. On the other hand, when the coverage rate is 35% or less, the proportion of toner core particles on the surface of the toner particles decreases. As a result, the toner particles become less prone to deformation, which further suppresses contamination of the material.

[0018] (Organosilicon polymer) The organosilicon polymer is preferably a condensed polymer of at least one compound selected from the group consisting of an organosilicon compound represented by the following formula (2), an organosilicon compound represented by the following formula (3), and an organosilicon compound represented by the following formula (4). [ka]

[0019] In equations (2), (3), and (4), R a and R b Each independently represents an alkyl group having 1 to 8 carbon atoms (more preferably 1 to 3), an alkenyl group having 1 to 8 carbon atoms (more preferably 1 to 3), or a phenyl group. 1 , R 2 , R 3 and R4 Each of these independently represents a hydrolyzable group. A hydrolyzable group is a halogen atom or an alkoxy group (preferably having 1 to 8 carbon atoms, more preferably 1 to 3 carbon atoms) that, during the condensation reaction of organosilicon compounds, forms bonds between organosilicon compounds via a hydroxyl group.

[0020] The compounds represented by formulas (2), (3), and (4) can be difunctional, trifunctional, or tetrafunctional organosilicon compounds. Among these, it is preferable to use a trifunctional organosilicon compound such as that represented by formula (3). That is, the organosilicon polymer is preferably a condensed polymer of an organosilicon compound containing the compound represented by formula (3), and more preferably a condensed polymer of an organosilicon compound represented by formula (3).

[0021] Examples of difunctional organosilicon compounds include dimethyldimethoxysilane and dimethyldiethoxysilane.

[0022] Examples of trifunctional organosilicon compounds include methyltrimethoxysilane, methyltriethoxysilane, methyldiethoxymethoxysilane, methylethoxydimethoxysilane, and ethyl Trifunctional alkyl group-containing silane compounds such as dimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, butyltrimethoxysilane, butyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltrimethoxysilane, octyltriethoxysilane; trifunctional alkenyl group-containing silane compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, allyltriethoxysilane; trifunctional aryl compounds such as phenyltrimethoxysilane, phenyltriethoxysilane Examples include group-containing silane compounds; silane compounds containing trifunctional methacryloxyalkyl groups such as γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropyldiethoxymethoxysilane, and γ-methacryloxypropylethoxydimethoxysilane; and silane compounds containing trifunctional acryloxyalkyl groups such as γ-acryloxypropyltrimethoxysilane, γ-acryloxypropyltriethoxysilane, γ-acryloxypropyldiethoxymethoxysilane, and γ-acryloxypropylethoxydimethoxysilane.

[0023] Examples of tetrafunctional organosilicon compounds include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane.

[0024] Furthermore, two or more organosilicon compounds may be used in combination. The organosilicon compounds used in combination may be those represented by formulas (2), (3), and (4) above, or other organosilicon compounds. Examples of organosilicon compounds other than those represented by formulas (2), (3), and (4) above include monofunctional organosilicon compounds. Examples of monofunctional organosilicon compounds include trimethylethoxysilane, triethylmethoxysilane, triethylethoxysilane, triisobutylmethoxysilane, triisopropylmethoxysilane, and tri-2-ethylhexylmethoxysilane.

[0025] (Release agent) There are no particular restrictions on the release agent used in the release agent domain, but from the viewpoint of ensuring release properties, it is preferable that it be a hydrocarbon wax. The release agent particles used in the release agent domain preferably have a number-average particle size of 50 nm to 300 nm, and more preferably 70 nm to 120 nm. By encapsulating release agent particles with a number-average particle size of 50 nm or more within the shell, the release agent can more easily seep out from the toner particles during fixing, resulting in a more sufficient release effect. Furthermore, when the number-average particle size of the release agent-encapsulated particles is 300 nm or less, the release agent domain in the shell portion of the toner particles becomes less prone to crushing, further improving durability.

[0026] Hydrocarbon waxes are waxes that have hydrocarbons as their backbone, and examples include Fischer-Tropsch wax, polyethylene wax, polypropylene wax, paraffin wax, and microcrystalline wax. Among these, paraffin wax is more preferred. In addition, multiple types of wax may be used.

[0027] In addition to the hydrocarbon waxes listed above, ester waxes may also be used. Examples of ester waxes include esters of monohydric alcohols and aliphatic monocarboxylic acids, such as behenyl behenate, stearyl stearate, and palmityl palmitate, or esters of monohydric alcohols and aliphatic monoalcohols; esters of dihydric alcohols and aliphatic monocarboxylic acids, such as dibehenyl sebacate and hexanediol dibehenate, or esters of dihydric alcohols and aliphatic monoalcohols; esters of trihydric alcohols and aliphatic monocarboxylic acids, such as glycerol tribehenate, or esters of trihydric alcohols and aliphatic monoalcohols; esters of tetrahydric alcohols and aliphatic monocarboxylic acids, such as pentaerythritol tetrastearate and pentaerythritol tetrapalmitate; and dipentaerythritol Esters of hexavalent alcohols such as iodine hexastearate and dipentaerythritol hexapalmitate with aliphatic monocarboxylic acids, or esters of hexavalent carboxylic acids with aliphatic monoalcohols; esters of polyhydric alcohols such as polyglycerin behenate with aliphatic monocarboxylic acids, or esters of polyhydric carboxylic acids with aliphatic monoalcohols; natural ester waxes such as carnauba wax, rice wax, and candelilla wax may also be used.

[0028] Furthermore, the melting point (Tm) of the release agent used in the release agent domain is preferably between 60°C and 100°C. If the melting point of the release agent is 60°C or higher, the shell will be less likely to collapse even during long-term durability, thus reducing the likelihood of toner fusion to the developing material. Also, if the melting point of the release agent is 100°C or lower, the release agent will melt quickly during fixing, resulting in improved release properties during fixing.

[0029] Next, we will describe the colorants, binders, waxes, charge control agents, and externally added inorganic fine particles contained in the toner core particles / toner particles as needed. (Coloring agent) The colorants contained in the toner core particles may include, without any particular limitations, known black, yellow, magenta, and cyan pigments, dyes, and magnetic materials of other colors. Examples of yellow pigments include monoazo compounds, disazo compounds, condensed azo compounds, isoindolinone compounds, isoindoline compounds, benzimidazolon compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds. Specifically, examples include CI Pigment Yellow 74, 93, 95, 109, 111, 128, 155, 174, 180, and 185.

[0030] Examples of magenta pigments include monoazo compounds, condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolon compounds, thioindigo compounds, and perylene compounds. Specifically, examples include CI Pigment Red 2, 3, 5, 6, 7, 23, 48:2, 48:3, 48:4, 57:1, 81:1, 122, 144, 146, 150, 166, 169, 177, 184, 185, 202, 206, 220, 221, 238, 254, 269, and CI Pigment Violet 19. Examples of cyanide pigments include copper phthalocyanine compounds and their derivatives, anthraquinone compounds, and basic dye lake compounds. Specifically, examples include CI Pigment Blue 1, 7, 15, 15:1, 15:2, 15:3, 15:4, 60, 62, and 66. Examples of black pigments include carbon black, aniline black, non-magnetic ferrite, and magnetite. Alternatively, black pigments that have been mixed using yellow, magenta, and cyan pigments may be used.

[0031] Furthermore, toner core particles can also be made into magnetic toner core particles by incorporating a magnetic material. In this case, the magnetic material can also serve as a coloring agent. Examples of magnetic materials include iron oxides such as magnetite, hematite, and ferrite; metals such as iron, cobalt, and nickel; or alloys and mixtures thereof of these metals with metals such as aluminum, cobalt, copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, and vanadium.

[0032] These pigments can be used individually, in combination, or even in solid solution form. Furthermore, various conventionally known dyes may be used in combination with the pigments as colorants. The coloring agent content is preferably 1.0 part by mass or more and 20.0 parts by mass or less per 100.0 parts by mass of the binder resin. When a magnetic material is used, it is preferably 50.0 parts by mass or more and 150.0 parts by mass or less per 100.0 parts by mass of the binder resin.

[0033] (Binding resin) The toner core particles contain a binder resin. The binder resin is not particularly limited, and any known resin can be used. Examples include vinyl resins, polyester resins, polyamide resins, furan resins, epoxy resins, xylene resins, and silicone resins. Among these, vinyl resins are preferred. Furthermore, as vinyl resins, polymers of monomers or copolymers thereof of styrene monomers such as styrene and α-methylstyrene, unsaturated carboxylic acid esters such as methyl acrylate, butyl acrylate, methyl methacrylate, 2-hydroxyethyl methacrylate, t-butyl methacrylate, and 2-ethylhexyl methacrylate (for example, alkyl (meth)acrylates having alkyl groups with 1 to 8 carbon atoms), unsaturated carboxylic acids such as acrylic acid and methacrylic acid, unsaturated dicarboxylic acids such as maleic acid, unsaturated dicarboxylic acid anhydrides such as maleic anhydride, nitrile vinyl monomers such as acrylonitrile, halogen-containing vinyl monomers such as vinyl chloride, and nitro vinyl monomers such as nitrostyrene can be used. In particular, it is preferable to use a copolymer of a styrene monomer and an unsaturated carboxylic acid ester.

[0034] (Release agent / Plasticizer) Toner core particles may contain waxes such as release agents and plasticizers. Toner core particles do not need to contain waxes. Examples of waxes include those mentioned above, as well as the following: Esters of monohydric alcohols such as behenyl behenate, stearyl stearate, and palmityl palmitate with aliphatic monocarboxylic acids, or esters of monohydric carboxylic acids with aliphatic monoalcohols; esters of dihydric alcohols such as dibehenyl sebacate and hexanediol dibehenate with aliphatic monocarboxylic acids, or esters of dihydric carboxylic acids with aliphatic monoalcohols; esters of trihydric alcohols such as glycerol tribehenate with aliphatic monocarboxylic acids, or esters of trihydric carboxylic acids with aliphatic monoalcohols; esters of tetrahydric alcohols such as pentaerythritol tetrastearate and pentaerythritol tetrapalmitate with aliphatic monocarboxylic acids, or esters of tetrahydric carboxylic acids with aliphatic monoalcohols; dipentaerythritol Esters of hexavalent alcohols such as hexastearate and dipentaerythritol hexapalmitate with aliphatic monocarboxylic acids, or esters of hexavalent carboxylic acids with aliphatic monoalcohols; esters of polyhydric alcohols such as polyglycerin behenate with aliphatic monocarboxylic acids, or esters of polyhydric carboxylic acids with aliphatic monoalcohols; natural ester waxes such as carnauba wax and rice wax; petroleum-based waxes such as paraffin wax, microcrystalline wax, and petrolatum and their derivatives; hydrocarbon waxes and their derivatives produced by the Fischer-Tropsch process; polyolefin waxes such as polyethylene wax and polypropylene wax and their derivatives; fatty acids such as higher aliphatic alcohols, stearic acid, and palmitic acid; acid amide waxes

[0035] (Charge control agent) The toner core particles may contain a charge control agent. Any conventionally known charge control agent can be used without any particular limitations. Specifically, as negative charge control agents, metal complexes of aromatic carboxylic acids such as salicylic acid, alkyl salicylic acid, dialkyl salicylic acid, naphthoic acid, and dicarboxylic acid, as well as polymers or copolymers having sulfonic acid groups, sulfonic acid bases, or sulfonic acid ester groups, Examples include metal salts or metal complexes of azo dyes or azo pigments, as well as boron compounds, silicon compounds, and calixarenes. Furthermore, examples of positive charge control agents include quaternary ammonium salts, polymeric compounds having quaternary ammonium salts in their side chains, guanidine compounds, nigrosine compounds, and imidazole compounds. As polymers or copolymers having sulfonic acid groups, sulfonic acid bases, or sulfonic acid ester groups, monopolymers of sulfonic acid group-containing vinyl monomers such as styrene sulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, 2-methacrylamide-2-methylpropanesulfonic acid, vinyl sulfonic acid, and methacrylic sulfonic acid, or copolymers of vinyl monomers and the above-mentioned sulfonic acid group-containing vinyl monomers, as shown in the section on binder resins, can be used. The amount of charge control agent added is preferably 0.01 parts by mass or more and 20.0 parts by mass or less per 100.0 parts by mass of the binder resin.

[0036] (Inorganic fine particles) Toner may be used as toner particles, or, if necessary, various inorganic fine particles may be added to the toner particles to obtain toner. Examples of inorganic fine particles include the following:

[0037] Silica, titanium dioxide, carbon black and carbon fluoride, metal oxides (e.g., strontium titanate, cerium oxide, alumina, magnesium oxide, chromium oxide), nitrides (e.g., silicon nitride), metal salts (e.g., calcium sulfate, barium sulfate, calcium carbonate), fatty acid metal salts (e.g., zinc stearate, calcium stearate).

[0038] Inorganic microparticles can also be hydrophobized to improve toner fluidity and equalize the charge of toner particles. Examples of treatment agents for hydrophobizing inorganic microparticles include unmodified silicone varnish, various modified silicone varnishes, unmodified silicone oil, various modified silicone oils, silane compounds, silane coupling agents, other organosilicon compounds, and organotitanium compounds. These treatment agents may be used individually or in combination.

[0039] Next, we will explain the toner manufacturing methods, but these are not the only methods. Toner can be obtained by first separately manufacturing release agent-encapsulated particles and toner core particles, then attaching the manufactured release agent-encapsulated particles to the surface of the toner core particles, and finally coating them with a polymer of organosilicon compound. This method will be described below.

[0040] The toner manufacturing method is preferably, A process to obtain mold release agent-encapsulated particles in which mold release agent particles are coated with an organosilicon polymer. A process to obtain a dispersion in which toner core particles are dispersed in an aqueous medium. A process of attaching release agent-encapsulated particles to the surface of toner core particles, and The process includes a step of obtaining toner particles by coating toner core particles to which release agent-encapsulated particles are attached with an organosilicon polymer.

[0041] (Method for producing mold release agent-encapsulated particles) Release agent-encapsulated particles are composite particles produced by coating release agent particles with an organosilicon polymer. The method for producing the release agent particles is not particularly limited. For example, those produced by known methods such as emulsification flocculation, soap-free emulsion polymerization, phase inversion emulsification, or mechanical emulsification can be used.

[0042] Next, a polymer coating layer is applied to the surface of the obtained release agent particles, consisting of at least one compound selected from the group consisting of organosilicon compounds represented by formulas (2), (3), and (4) described above. By forming this, mold release agent-encapsulated particles can be obtained. Known methods can be used to form a coating layer of organosilicon polymer on the surface of the mold release agent particles. For example, methods include adding the organosilicon compound directly, or mixing the organosilicon compound, such as alkoxysilane, with an aqueous medium, hydrolyzing it, and then adding it. Organosilicon compounds like the alkoxysilanes mentioned above undergo a condensation reaction after hydrolysis. Since the optimal pH for the hydrolysis reaction and the condensation reaction are different, it is preferable to mix the organosilicon compound with the aqueous medium beforehand, hydrolyze it at a pH that allows for a faster hydrolysis reaction, and then add it to shorten the reaction time.

[0043] (Method for producing toner core particles) The method for producing toner core particles is not particularly limited, but examples include suspension polymerization, dissolution-suspension, emulsification-coagulation, and pulverization. If toner core particles are produced in an aqueous medium, the dispersion containing the toner core particles may be used directly in the next step (the step of attaching release agent-encapsulated particles), or the toner core particles may be washed, filtered, and dried before being redispersed in the aqueous medium. If toner core particles are produced by a dry method, they can be dispersed in an aqueous medium by known methods. It is preferable that the aqueous medium contains a dispersion stabilizer in order to disperse the toner core particles in the aqueous medium.

[0044] As an example of a method for manufacturing toner core particles, we will describe the suspension polymerization method. When obtaining toner core particles by suspension polymerization, a polymerizable monomer for generating a binder resin, along with various materials as needed (colorants, waxes, charge control agents, polar resins, etc.), are added, and a polymerizable monomer composition is prepared by melting, dissolving, or dispersing these materials using a disperser. At this time, solvents for viscosity adjustment, crystalline resins, chain transfer agents, and other additives may be added as needed. Examples of dispersers include homogenizers, ball mills, colloid mills, and ultrasonic dispersers.

[0045] Next, the polymerizable monomer composition is added to an aqueous medium containing pre-prepared poorly water-soluble inorganic fine particles, and a suspension is prepared using a high-speed dispersant such as a high-speed stirrer or ultrasonic disperser (granulation step). Examples of poorly water-soluble inorganic fine particles include phosphates such as hydroxyapatite, tricalcium phosphate, dicalcium phosphate, magnesium phosphate, aluminum phosphate, and zinc phosphate; carbonates such as calcium carbonate and magnesium carbonate; metal hydroxides such as calcium hydroxide, magnesium hydroxide, and aluminum hydroxide; sulfates such as calcium sulfate and barium sulfate; calcium metasilicate; bentonite; silica; and alumina.

[0046] Subsequently, polymerization is initiated by adding a polymerization initiator to the polymerizable monomer in the suspension, generating a binder resin and forming toner core particles (polymerization process). The polymerization initiator may be mixed with other additives when preparing the polymerizable monomer composition, or it may be mixed into the polymerizable monomer composition immediately before suspension in an aqueous medium. It can also be added, if necessary, dissolved in the polymerizable monomer or other solvents during or after granulation, i.e., immediately before initiating the polymerization reaction. After polymerizing the polymerizable monomer to produce a binder resin, a depolymerizable monomer treatment is performed as needed to form an aqueous dispersion of toner core particles.

[0047] Furthermore, the glass transition temperature (Tg) of the toner core particles is preferably 40°C to 75°C, and more preferably 40°C to 65°C. In addition, the peak molecular weight (Mp) of the toner core particles, as measured by gel permeation chromatography (GPC), is preferably 5000 to 50000.

[0048] (Method for fixing release agent-encapsulated particles to the surface of toner core particles) The method for attaching the release agent-encapsulated particles to the surface of the toner core particles is not particularly limited. For example, after adding release agent-encapsulated particles to a dispersion of toner core particles, the aqueous medium may be heated (preferably 40-70°C, more preferably 50-60°C) to cause adhesion, or a flocculant may be added to cause adhesion. The above methods may be combined, and in any case, it is preferable to stir the aqueous medium.

[0049] More preferably, the release agent-encapsulated particles and toner core particles are heated to the above temperature while coexisting in an aqueous medium, and the pH is adjusted to a level that facilitates the dispersion of the release agent-encapsulated particles in the aqueous medium, thereby allowing them to adhere. This method allows the release agent-encapsulated particles to adhere to the surface of the toner core particles in a dispersed state, and also reduces the likelihood of aggregation between the toner core particles. The pH when the release agent-encapsulated particles are attached to the surface of the toner core particles is preferably 5.0 to 7.0, and more preferably 5.0 to 6.0. The holding time when the release agent-encapsulated particles are attached to the surface of the toner core particles is not particularly limited, but is preferably 5 to 300 minutes, and more preferably 30 to 120 minutes.

[0050] (Toner core particle coating method) The following describes a method for coating toner core particles to which release agent-encapsulated particles are attached with an organosilicon polymer, but it is not limited to this method. A preferred method of preparation involves preparing a mixed solution containing an organosilicon compound or its hydrolysate and toner core particles with release agent-encapsulated particles attached in an aqueous medium, and then condensing the organosilicon compound. For example, a hydrolysate of an organosilicon compound is added to a dispersion containing toner core particles with release agent-encapsulated particles attached, and the pH is controlled to condense the organosilicon compound.

[0051] The organosilicon compound can be added to and mixed with an aqueous medium by any method. For example, the organosilicon compound may be added directly. Alternatively, it may be added after being mixed with an aqueous medium and hydrolyzed. The temperature during condensation is preferably 40 to 70°C, more preferably 50 to 60°C. The holding time during condensation is not particularly limited, but is preferably 30 to 500 minutes, and more preferably 100 to 300 minutes.

[0052] Furthermore, while the pH of the aqueous medium during condensation is not particularly limited, it is preferably 7.0 or higher, more preferably 8.0 to 11.0, and even more preferably 9.0 to 10.0. The pH of an aqueous medium or mixed solution can be adjusted with an existing acid or base. Acids that can be used to adjust pH include: hydrochloric acid, bromic acid, iodic acid, perchloric acid, perbromic acid, metaperiodic acid, permanganic acid, thiocyanic acid, sulfuric acid, nitric acid, phosphonic acid, phosphoric acid, diphosphate, hexafluorophosphate, tetrafluoroboric acid, tripolyphosphate, aspartic acid, o-aminobenzoic acid, p-aminobenzoic acid, isonicotinic acid, oxaloacetate, citric acid, 2-glycerol phosphate, glutamic acid, cyanoacetic acid, oxalic acid, trichloroacetic acid, o-nitrobenzoic acid, nitroacetic acid, picric acid, picolinic acid, pyruvic acid, fumaric acid, fluoroacetic acid, bromoacetic acid, o-bromobenzoic acid, maleic acid, and malonic acid.

[0053] Examples of bases used to adjust pH include: alkali metal hydroxides and aqueous solutions thereof, such as potassium hydroxide, sodium hydroxide, and lithium hydroxide; alkali metal carbonates and aqueous solutions thereof, such as potassium carbonate, sodium carbonate, and lithium carbonate; alkali metal sulfates and aqueous solutions thereof, such as potassium sulfate, sodium sulfate, and lithium sulfate; alkali metal phosphates and aqueous solutions thereof, such as potassium phosphate, sodium phosphate, and lithium phosphate; alkaline earth metal hydroxides and aqueous solutions thereof, such as calcium hydroxide and magnesium hydroxide; basic amino acids and aqueous solutions thereof, such as ammonia, histidine, arginine, and lysine; and trishydroxymethylaminomethane. Preferred aqueous media include water, methanol, alcohols such as ethanol and propanol, and mixtures thereof.

[0054] The measurement methods for each physical property are described below. (Particle size of toner particles or toner core particles) The number-average particle size (D1) and weight-average particle size (D4) of toner particles or toner core particles (hereinafter referred to as toner particles in this measurement method) are calculated as follows. The measurement device used is the "Coulter Counter Multisizer 3" (manufactured by Beckman Coulter, Inc.), a precision particle size distribution analyzer using the pore electrical resistance method equipped with a 100 μm aperture tube. The setting of measurement conditions and analysis of measurement data are performed using the accompanying dedicated software "Beckman Coulter Multisizer 3 Version 3.51" (manufactured by Beckman Coulter, Inc.). The measurement is performed with an effective measurement channel count of 25,000 channels. The electrolytic aqueous solution used for measurement is prepared by dissolving special grade sodium chloride in deionized water to a concentration of 1%, for example, "ISOTON II" (manufactured by Beckman Coulter, Inc.). Before performing measurements and analysis, configure the dedicated software as follows. In the "Change Standard Measurement Method (SOMME)" screen of the dedicated software, set the total count in control mode to 50,000 particles, the number of measurements to 1, and the Kd value to the value obtained using "Standard Particle 10.0 μm" (manufactured by Beckman Coulter, Inc.). Press the "Measure Threshold / Noise Level Button" to automatically set the threshold and noise level. Also, set the current to 1,600 μA, the gain to 2, the electrolyte to ISOTON II, and check "Flush aperture tube after measurement". In the "Pulse to Particle Size Conversion Settings" screen of the dedicated software mentioned above, set the bin spacing to logarithmic particle size, the particle size bins to 256 particle size bins, and the particle size range from 2 μm to 60 μm. The specific measurement method is as follows:

[0055] (1) Place 200 mL of the electrolytic solution into a 250 mL round-bottom glass beaker specifically designed for the Multisizer 3, set it on the sample stand, and stir the mixture with the stirrer rod at 24 revolutions per second in a counterclockwise direction. Then, use the "Aperture Tube Flash" function of the dedicated software to remove any dirt and air bubbles from inside the aperture tube. (2) Place 30 mL of the electrolytic aqueous solution into a 100 mL flat-bottomed glass beaker. Add 0.3 mL of a diluted solution of "Contaminon N" (a 10% aqueous solution of a pH 7 neutral detergent for cleaning precision measuring instruments, consisting of a nonionic surfactant, anionic surfactant, and organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) diluted three times by mass with deionized water as a dispersant. (3) Prepare an "Ultrasonic Dispension System Tetra150" (manufactured by Nikko Bios Co., Ltd.), an ultrasonic disperser with an electrical output of 120W and two oscillators with an oscillation frequency of 50kHz and a phase shift of 180 degrees. Add 3.3L of deionized water to the water tank of the ultrasonic disperser and add 2mL of Contaminon N to this water tank. (4) Set the beaker from (2) into the beaker fixing hole of the ultrasonic disperser and operate the ultrasonic disperser. Then, adjust the height of the beaker so that the resonance state of the liquid surface of the electrolytic aqueous solution in the beaker is maximized. (5) While irradiating the electrolytic aqueous solution in the beaker described in (4) with ultrasound, add 10 mg of toner particles to the electrolytic aqueous solution in small amounts and disperse them. Continue the ultrasonic dispersion treatment for another 60 seconds. During ultrasonic dispersion, adjust the water temperature in the tank to be between 10°C and 40°C as appropriate. (6) Using a pipette, the electrolyte aqueous solution from (5) containing dispersed toner particles is dropped into the round-bottom beaker from (1) placed in the sample stand, and the concentration is adjusted to 5%. The measurement is then carried out until the number of particles to be measured reaches 50,000. (7) The measurement data is analyzed using the dedicated software attached to the device, and the number-average particle size (D1) is calculated. Calculate the weight-average particle size (D4).

[0056] (Peak molecular weight of toner core particles) The peak molecular weight (Mp) of toner core particles is measured by gel permeation chromatography (GPC) as follows: First, the sample is dissolved in tetrahydrofuran (THF) at room temperature. Then, the resulting solution is filtered through a solvent-resistant membrane filter, "Myshori Disc" (manufactured by Tosoh Corporation), with a pore diameter of 0.2 μm, to obtain the sample solution. The sample solution is adjusted so that the concentration of components soluble in THF is 0.8% by mass. This sample solution is then used for measurement under the following conditions. Equipment: High-speed GPC system "HLC-8220GPC" [manufactured by Tosoh Corporation] Column: LF-604, double column [Manufactured by Showa Denko Corporation] Eluent:THF Flow rate: 0.6mL / min Oven temperature: 40℃ Sample injection volume: 0.020 mL For calculating the molecular weight of the sample, a molecular weight calibration curve prepared using, for example, the standard polystyrene resin described below is used. Standard polystyrene resin: Product 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.

[0057] (Particle size of release agent particles and release agent-encapsulated particles) The number-average particle size of the release agent particles and the particles containing the release agent is calculated by measuring the particle size using dynamic light scattering (DLS) with a zetasizing device Nano-ZS (MALVERN). First, turn on the device and wait 30 minutes for the laser to stabilize. Then, launch the Zetasizer software. Select Manual from the Measure menu and enter the measurement details as shown below. Measurement mode: Particle size Material:Polystyrene latex(RI:1.59, Absorption:0.01) Dispersant:Water(Temperature:25℃, Viscosity:0.8872cP, RI:1.330) Temperature: 25.0℃ Cell:Clear disposable zeta cell Measurement duration: Automatic The sample is diluted with water to a concentration of 0.50% by mass, filled into a disposable cell, and then loaded into the cell holder of the apparatus. Once the above preparations are complete, press the Start button on the measurement display screen to begin the measurement. Based on the number-based particle size distribution data obtained by transforming the light intensity distribution from DLS measurements using Mie theory, the number-average particle size is calculated.

[0058] (Confirmation of the coating layer by organosilicon polymer in release agent-encapsulated particles) To confirm the presence of a coating layer by an organosilicon polymer in release agent-encapsulated particles, the following procedure is followed: First, the release agent-encapsulated particles are thoroughly dispersed in a room-temperature curing epoxy resin, and then cured for two days in a 40°C atmosphere. From the resulting cured product, a 40 nm thick flaky sample is cut out using a microtome equipped with a diamond blade. Subsequently, a transmission electron microscope (TEM, model name: JEM-2800, manufactured by JEOL Ltd.) was used. The release agent-encapsulated particles are observed using [a specific method]. Here, silicon atom mapping is performed using EDX (energy-dispersive X-ray spectroscopy). The locations of silicon atoms are identified as the locations of the organosilicon polymer, and it is confirmed that a coating layer of the organosilicon polymer is formed on the surface of the release agent-encapsulated particles.

[0059] (Glass transition temperature (Tg) of toner) The glass transition temperature (Tg) of the toner is measured using a differential scanning calorimetry analyzer "Q2000" (TA Instruments) in accordance with ASTM D3418-82. The temperature correction for the instrument's detection unit uses the melting points of indium and zinc, and the heat of fusion of indium is used for heat quantity correction. Specifically, 3 mg of toner is accurately weighed and placed in an aluminum pan, with an empty aluminum pan used as a reference. Measurements are taken within the measurement range of 30°C to 200°C, with a heating rate of 10°C / min. The specific heat change is obtained during this heating process. The glass transition temperature (Tg) of the toner is defined as the temperature at the point where the curve representing the stepwise transition portion of the glass transition intersects with a straight line equidistant in the vertical direction from the extended straight line of each baseline before and after the specific heat change of the reversible specific heat change curve is obtained.

[0060] (Melting point of release agent) The melting point of the release agent used in the release agent particles is measured using a differential scanning calorimetry analyzer "Q2000" in accordance with ASTM D3418-82, similar to the measurement of the glass transition temperature (Tg) of the toner. The temperature correction of the instrument's detection unit uses the melting points of indium and zinc, and the heat of fusion of indium is used for heat quantity correction. Specifically, 1 mg of release agent particles are accurately weighed and placed in an aluminum pan. An empty aluminum pan is used as a reference, and measurements are taken within the temperature range of 30 to 200°C at a heating rate of 10°C / min. During the measurement, the temperature is first raised to 200°C at a heating rate of 10°C / min, then cooled to 30°C at a cooling rate of 10°C / min, and then heated again. The maximum endothermic peak in the DSC curve within the temperature range of 30 to 200°C during this second heating process is defined as the melting point of the release agent.

[0061] (Observation of the toner particle surface) Observation of the toner particle surface is performed as follows: Inject liquid nitrogen into the anti-contamination trap attached to the scanning electron microscope (SEM, instrument name: S-4800, manufactured by Hitachi, Ltd.) until it overflows, and leave it for 30 minutes. Start the "PC-SEM" on the S-4800 and perform flushing (cleaning of the FE tip, which is the electron source). Click on the acceleration voltage display section on the control panel on the screen, and press the [Flushing] button to open the flushing execution dialog. Confirm that the flushing intensity is 2 and execute. Confirm that the emission current due to flushing is 20-40A. Insert the sample holder with the toner particles fixed into the sample chamber of the S-4800 microscope body. Press [Origin] on the control panel to move the sample holder to the observation position.

[0062] Click the acceleration voltage display to open the HV settings dialog, and set the acceleration voltage to [2.0kV] and the emission current to [10μA]. In the [Basic] tab of the operation panel, set the signal selection to [SE] and set the SE detector to [Mixed]. Similarly, in the [Basic] tab of the operation panel, set the probe current in the electron optical system conditions block to [Normal], the focus mode to [UHR], and the WD to [3.0mm]. Press the [ON] button on the acceleration voltage display section of the control panel to apply the acceleration voltage.

[0063] (Calculation of toner particle coverage in scanning electron microscopy) The area percentage (coverage rate) of organosilicon polymers on the surface of toner particles is determined by scanning electronic scanning. The ratio of the bright area to the total area, obtained by observing backscattered electron images using a microscope, is used. The area ratio of the bright areas is calculated by observing the toner surface using a scanning electron microscope. A 1.5 μm square backscattered electron image of the toner surface is acquired, and the image is obtained by binarizing the backscattered electron image so that the organosilicon polymer portion in the backscattered electron image becomes the bright area. The ratio of the bright area of ​​the obtained image to the total area of ​​the obtained image is calculated. The 1.5 μm square backscattered electron image of the toner surface is acquired using a scanning electron microscope (SEM).

[0064] The specific SEM equipment and observation conditions are as follows: Equipment used: ULTRA PLUS manufactured by Carl Zeiss Microscopy Co., Ltd. Acceleration voltage: 1.0kV WD: 2.0mm Aperture Size: 30.0 μm Detection signal: EsB (Energy-selective backscattered electrons) EsB Grid: 800V Observation magnification: 50,000x Contrast: 63.0 ± 5.0% (reference value) Brightness: 38.0 ± 5.0% (reference value) Image size: 1024 x 768 pixels Pre-treatment: Toner particles are scattered onto carbon tape (no vapor deposition is performed).

[0065] The acceleration voltage and EsB grid are set to achieve objectives such as acquiring structural information of the toner particle's outermost surface, preventing charge-up in undeposited samples, and selectively detecting high-energy backscattered electrons. The observation field is selected to be near the apex where the curvature of the toner particle is smallest. The area ratio of the bright area to the total area of ​​the backscattered electron image was calculated by analyzing the backscattered electron image of the toner particle surface obtained by the above method using the image processing software ImageJ (developed by Wayne Rashand). The procedure is as follows.

[0066] First, convert the backscattered electron image to 8-bit using the Image menu's Type option. Next, reduce image noise by setting the Median diameter to 2.0 pixels using the Process menu's Filters option. After excluding the observation conditions display at the bottom of the backscattered electron image, estimate the image center and use the Rectangle Tool on the toolbar to select a 1.5 μm square area from the center of the backscattered electron image.

[0067] Next, select Threshold from the Adjust menu in the Image menu. Select Default, click Auto, and then click Apply to obtain the binarized image. This operation will display the bright areas of the backscattered electron image in white. Again, after removing the observation conditions display at the bottom of the backscattered electron image, estimate the image center and use the Rectangle Tool on the toolbar to select a 1.5 μm square area from the center of the backscattered electron image.

[0068] Next, select Histogram from the Analyze menu. Read the Count value from the newly opened Histogram window (this corresponds to the total area of ​​the backscattered electron image). Also, click List and read the Count value when the brightness is 0 (this corresponds to the bright area of ​​the backscattered electron image). From the above values, calculate the area ratio of the bright area to the total area of ​​the backscattered electron image. The above procedure is performed for 10 fields of view for each toner particle to be evaluated, and the average number is calculated to determine the area percentage (coverage rate) occupied by the organosilicon polymer on the surface of the toner particle.

[0069] (Observation of release agent domains using a transmission electron microscope) The release agent domains embedded within the toner particle shells are observed by observing cross-sectional layers using a transmission electron microscope (TEM, instrument name: JEM-2800, manufactured by JEOL Ltd.). The procedure for observing the cross-section of toner particles is as follows: The toner is embedded in a visible light-curable embedding resin (D-800, manufactured by Nisshin EM Co., Ltd.) and then cut to a thickness of 70 nm using an ultrasonic ultramicrotome (UC7, manufactured by Leica). From the obtained thin section samples, select 10 toner particles whose cross-sectional diameter is within ±2.0 μm of the weight-average particle size (D4). The selected thin section samples were stained with a vacuum staining system (VSC4R1H, Philgen) in a RuO4 gas atmosphere at 500 Pa for 15 minutes, and TEM images were created using the scanning mode of a scanning transmission electron microscope (JEM-2800, JEOL). Images were acquired using a TEM probe size of 1 nm and an image size of 1024 × 1024 pixels. Additionally, the TEM image was acquired with the following settings: Contrast 1425 and Brightness 3750 in the Detector Control panel for brightfield images, and Contrast 0.0, Brightness 0.5, and Gamma 1.00 in the Image Control panel.

[0070] (Calculation of the average value D of the shortest distance from the release agent domain to the surface of the toner particles) From the TEM images of the toner particle cross-section obtained by the above method, 30 release agent domains are selected, the shortest distance from each release agent domain to the surface of the toner particle is determined, and the average value of these values ​​is taken as the average of the shortest distance D from the release agent domain to the surface of the toner particle.

[0071] (Calculation of the area percentage of the release agent domain relative to the toner core particles) In the TEM image of the toner particle cross-section obtained by the above method, the area of ​​the toner core particle and the area of ​​the total release agent domain in one toner particle are determined, respectively. This is done for 10 toner particles, and the arithmetic mean of the area of ​​the toner core particle is taken as (S1), and the arithmetic mean of the sum of the areas of the total release agent domains per toner particle is taken as (S2), and the area ratio S2 / S1 × 100 (area %) is calculated. Each area can be calculated from a binarized image using the image processing software "Image J" (developed by Wayne Rasband). The calculation procedure is as follows. A) Take TEM images at a magnification that captures the entire toner core particle and a magnification that resolves the release agent domain. B) Convert the backscattered electron image to be analyzed to 8-bit using [Image]-[Type]. C) Set the scale using [Analyze]-[Set Scale]. D) Use [Process]-[Noise]-[Despeckle] to blur everything except the contours. E) Use [Image]-[Adjust]-[Threshold] to set a threshold and binarize the image. (Set the threshold to a value that leaves no noise and retains the core and release agent domains that are the target of measurement (specifically, Auto). Check [Dark background] as needed so that the toner core particles or release agent domains are filled in red during processing.) F) With the area to be calculated filled in red, use [Freehands Selections] to select the area to be calculated (toner core area or release agent domain area). G) In [Analyze]-[Set Measurements], check [Area] and [Limit to Threshold]. H) Perform the analysis using [Analyze]-[Measure]. The value displayed in Results is the area of ​​the filled region. In this way, you can obtain the area of ​​the toner core particle region and the area of ​​the total release agent domain. I) Perform the same analysis on the remaining 9 toner cartridges that were observed.

[0072] (Calculation of the non-contact ratio between the release agent domain and the core, and confirmation of domain inclusion) Silicon atom mapping is performed on the obtained TEM images of the toner particle cross-sections using EDX (Energy Dispersive X-ray Spectroscopy). The non-contact ratio between the release agent domains and the toner core particles is calculated by denoting X as the number of release agent domains observed in the toner particle cross-section, and Y as the number of release agent domains that are in direct contact with the toner core particles, even partially, without the intervening shell of the organosilicon polymer. The non-contact ratio is calculated using the following formula. Note that this is calculated from all release agent domains present in the 10 toner particle cross-sections selected above. Non-contact rate (number of items %) = 100 - (Y / X × 100) Furthermore, the image obtained by the silicon atom mapping described above is used to confirm whether the shell containing the organosilicon polymer contains a mold release agent domain.

[0073] (Method for measuring secondary ion mass / secondary ion charge number (m / z) by time-of-flight secondary ion mass spectrometry (TOF-SIMS)) For peak intensity measurement using TOF-SIMS, we will use the TRIFT-IV from ULVAC-FI. The fragment ion peaks on the toner particle surface will be confirmed using the following equipment under the following conditions. Sample preparation: Toner particles are attached to an indium sheet. Sample pretreatment: None Primary ion: Au ion Acceleration voltage: 30kV Charge neutralization mode: On Measurement mode: Positive Raster: 200 μm Measurement time: 60s

[0074] Furthermore, the depth profile analysis of toner particles is performed by sputtering the toner particles with argon gas cluster ions and abrading the surface. The sputtering conditions are as follows: Acceleration voltage: 10kV Current: 3.4nA Raster: 600 μm Irradiation time: 5 seconds To measure the depth, we first confirmed the relationship between irradiation time and sputtering a PMMA film under the same conditions, and confirmed that 100 nm of material was removed in 300 seconds. The above apparatus is used under the above conditions, and it is confirmed that fragment ion peaks corresponding to the structure shown in formula (1) appear in the region corresponding to the release agent domain. If the region corresponding to the release agent domain does not appear after the above irradiation time, the sputtering is repeated until the release agent domain appears. The fragment ion peaks corresponding to the structure shown in formula (1) are characterized by appearing at molecular weight intervals of 14. In addition to the silicon atom mapping described above, the presence of the release agent domain within the shell may be confirmed in detail by checking whether the fragment ion peak appears when sputtering is performed using depth profile analysis. [Examples]

[0075] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, all "parts" and "%" of each material in the examples and comparative examples are on a mass basis.

[0076] (Preparation of organosilicon compound solution 1) • Ion-exchanged water 50.0 parts • Methyltrimethoxysilane (organosilicon compound) 50.0 parts The above materials were mixed, and the pH was adjusted to 4.0 with 1 mol / L hydrochloric acid. Then, the mixture was stirred for 1 hour while being heated in a water bath at 60°C to prepare organosilicon compound solution 1.

[0077] (Preparation of organosilicon compound solutions 2-4) Organosilicon compound solutions 2 to 4 were prepared in the same manner as the preparation of organosilicon compound solution 1, except that the types of organosilicon compounds were changed as shown in Table 1 below. [Table 1]

[0078] (Preparation of mold release agent particles 1) • Release agent (HNP-9 (paraffin wax), melting point 75℃, Nippon Seiro) 20 units • Anionic surfactant (manufactured by Daiichi Kogyo Seiyaku: Neogen RK) 1 part • Ion-exchanged water (45 parts) The above materials were placed in a mixing container equipped with a stirring device and heated to 90°C. Next, the mixture was circulated through a CreaMix W Motion CLM-2.2 / 3.7W (manufactured by M-Technique) and stirred in a shear stirring section with a rotor outer diameter of 3 cm and a clearance of 0.3 mm at a rotor rotation speed of 19,000 rpm and a screen rotation speed of 18,000 rpm for 60 minutes, followed by dispersion treatment. Subsequently, a dispersion of release agent particles 1 was obtained by cooling to 40°C under cooling conditions of rotor rotation speed of 1000 rpm, screen rotation speed of 0 rpm, and cooling rate of 10°C / min. The number-average particle size (D1) of the obtained release agent particles 1 was 90 nm.

[0079] (Preparation of mold release agent particles 2-7) Dispersions of release agent particles 2 to 7 were prepared in the same manner as for release agent particle 1, except that the type of dispersed phase used, the amount of anionic surfactant, and the stirring conditions were changed as shown in Table 2 below.

[0080] (Preparation of resin particles 8) To an oil phase containing 78.0 parts styrene and 22.0 parts butyl acrylate, 150 parts of a 1.5% aqueous solution of Neogen RK (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was added and dispersed. While stirring slowly for another 10 minutes, an aqueous solution of 0.3 parts potassium persulfate and 10.0 parts deionized water was added. After nitrogen purging, emulsion polymerization was carried out at 70°C for 6 hours. After polymerization was complete, the reaction solution was cooled to room temperature, and deionized water was added to obtain an aqueous dispersion of resin particles 8 with a solid content of 12.5% ​​by mass. The number-average particle size (D1) of resin particles 8 was 250 nm. Note that the resin particles 8 do not have release properties and are not a mold release agent. [Table 2] Excellex 48070B and Excellex 15341PA are polyethylene wax (manufactured by Mitsui Chemicals, Inc.).

[0081] (Preparation of mold release agent-encapsulated particle 1) • Release agent particles 1: 7.0 parts • Organosilicon compound solution 1: 4.0 parts • Ion-exchanged water: 500 copies After adding the above materials to a mixing container equipped with a stirring device, the pH was adjusted to 9.6 with a 7.3% sodium bicarbonate aqueous solution, and the mixture was stirred at room temperature for 5 hours to obtain a dispersion of release agent-encapsulated particles 1.

[0082] (Preparation of mold release agent-encapsulated particles 2-11) Dispersions of release agent-encapsulated particles 2-11 were obtained in the same manner as for release agent-encapsulated particles 1, except that the amount of organosilicon compound solution 1 was changed as shown in Table 3 below.

[0083] (Preparation of mold release agent-encapsulated particles 12-17 and resin-encapsulated particles 18) Dispersions of mold release agent-encapsulated particles 12-17 and resin-encapsulated particles 18 were obtained in the same manner as for mold release agent-encapsulated particles 1, except that the type of mold release agent particle was changed as shown in Table 3 below. [Table 3]

[0084] (Preparation of toner core particle 1) 390.0 parts of deionized water in a reaction vessel were mixed with 14.0 parts of sodium phosphate (manufactured by Rasa Industries Co., Ltd., dodecahydrate), and the mixture was kept warm at 65°C for 1.0 hour while purging with nitrogen. Using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), a calcium chloride aqueous solution, prepared by dissolving 9.2 parts calcium chloride (dihydrate) in 10.0 parts ion-exchanged water, was added to the reaction vessel in one go while stirring at 12,000 rpm to prepare an aqueous medium containing a dispersion stabilizer. Furthermore, 10% hydrochloric acid was added to the aqueous medium in the reaction vessel to adjust the pH to 6.0, and aqueous medium 1 was prepared.

[0085] (Preparation of polymerizable monomer compositions) • Styrene 60.0 parts CI Pigment Blue 15:3 6.5 parts The above materials were placed in an attritor (manufactured by Nippon Coke Industries Co., Ltd.), and then dispersed using 1.7 mm diameter zirconia particles at 220 rpm for 5.0 hours to prepare a pigment dispersion.

[0086] Next, the following materials were added to the pigment dispersion. • Styrene 10.0 parts n-butyl acrylate 30.0 parts • Polyester resin 5.0 parts (A polymer of terephthalic acid and a 2-mol adduct of bisphenol A propylene oxide, weight-average molecular weight 10,000, acid value: 8.2 mg KOH / g) This was kept warm at 65°C, and then uniformly dissolved and dispersed at 500 rpm using a TK homomixer to prepare a polymerizable monomer composition.

[0087] (granulation process) While maintaining the temperature of the aqueous medium 1 at 70°C and the rotation speed of the stirring device at 12,000 rpm, the polymerizable monomer composition was added to the aqueous medium 1, and 9.0 parts of t-butyl peroxypivalate, a polymerization initiator, were added. Granulation was then carried out for 10 minutes while maintaining the stirring speed at 12,000 rpm.

[0088] (Polymerization process) The stirrer was changed from a high-speed stirrer to a propeller-type stirrer, and polymerization was carried out for 5.0 hours while stirring at 150 rpm and maintaining a temperature of 70°C. The polymerization reaction was then carried out by raising the temperature to 85°C and heating for 2.0 hours to obtain a dispersion of toner core particles 1. The weight-average particle size (D4) of toner core particles 1 was 6.7 μm.

[0089] (Preparation of toner core particles 2) First, a pigment dispersion was prepared in the same manner as the preparation method for toner core particles 1. Next, the following materials were added to the pigment dispersion, and then granulation and polymerization were carried out in the same manner as the preparation method for toner core particles 1 to obtain a dispersion of toner core particles 2. The weight-average particle size (D4) of toner core particles 2 was 6.8 μm. • Styrene 10.0 parts n-butyl acrylate 30.0 parts • Polyester resin 5.0 parts (A polymer of terephthalic acid and a 2-mol adduct of bisphenol A propylene oxide, weight-average molecular weight 10,000, acid value: 8.2 mg KOH / g) • Release agent (HNP-9, melting point 75℃, Nippon Seiro) 5.0 parts

[0090] (Manufacturing method for toner 1) The following samples were weighed into a reaction vessel and mixed using a propeller stirring blade. • Toner core particles 1: 100 copies • Release agent-encapsulated particles 1: 58 parts Next, the mixture was heated to 55°C and then kept at that temperature for 1 hour while being mixed using a propeller agitator. Next, the pH of the mixture was adjusted to 5.6, then 2.8 parts of organosilicon compound solution 1 were added and stirred. The pH was then adjusted to 9.6 using a 7.3% sodium bicarbonate aqueous solution, and the mixture was kept in place for 4 hours while being mixed with a propeller stirring blade, before being air-cooled until the temperature reached 25°C. A 10% hydrochloric acid aqueous solution was added to the resulting mixture, the pH was adjusted to 1.5, and the mixture was stirred for 2 hours. After that, it was filtered, washed with water, and dried to obtain toner particles 1. These were designated as toner 1.

[0091] (Manufacturing method for toners 2-19 and 22) Toners 2-19 and 22 were obtained in the same manner as the manufacturing method for toner 1, except that the types and amounts of the organosilicon compound liquid and release agent-encapsulated particles were changed as shown in Table 4.

[0092] (Manufacturing method for toner 20) The following samples were weighed into a reaction vessel and mixed using a propeller stirring blade. • Toner core particles 1: 100 copies • Release agent-encapsulated particles 1: 58 parts Next, the mixture was heated to 55°C and then kept at that temperature for 1 hour while being mixed using a propeller agitator. Next, after adjusting the pH of the mixture to 5.6, add 1.4 parts of organosilicon compound solution 1. The mixture was stirred, and the pH was adjusted to 11.6 using a 1 mol / L sodium hydroxide solution. After stirring with a propeller-type stirring blade for 4 hours, the mixture was air-cooled to 25°C. A 10% hydrochloric acid aqueous solution was added to the resulting mixture, the pH was adjusted to 1.5, and the mixture was stirred for 2 hours. After that, it was filtered, washed with water, and dried to obtain toner particles 20. These were designated as toner 20.

[0093] (Manufacturing method for toner 21) The following samples were weighed into a reaction vessel and mixed using a propeller stirring blade. • Toner core particles 1: 100 copies • Release agent-encapsulated particles 1: 58 parts Next, the mixture was heated to 55°C and then kept at that temperature for 1 hour while being mixed using a propeller agitator. Next, the pH of the mixture was adjusted to 5.6, then 2.1 parts of organosilicon compound solution 1 were added and stirred, and the pH was adjusted to 11.6 using a 1 mol / L sodium hydroxide aqueous solution. The mixture was kept in place for 4 hours while being mixed with a propeller stirring blade, and then air-cooled until the temperature reached 25°C. A 10% hydrochloric acid aqueous solution was added to the resulting mixture, the pH was adjusted to 1.5, and the mixture was stirred for 2 hours. After that, it was filtered, washed with water, and dried to obtain toner particles 21. These were designated as toner 21.

[0094] (Manufacturing method for toner 23) The following samples were weighed into a reaction vessel and mixed using a propeller stirring blade. • Toner core particles 1: 100 copies • Release agent-encapsulated particles 1: 58 parts Next, the mixture was heated to 55°C and then kept at that temperature for 1 hour while being mixed using a propeller agitator. Next, the pH of the mixture was adjusted to 5.6, then 2.6 parts of organosilicon compound solution 1 were added and stirred. The pH was then adjusted to 9.6 using a 7.3% sodium bicarbonate aqueous solution, and the mixture was stirred using a propeller stirring blade. After 10 minutes, 1.5 parts of organosilicon compound solution 1 were added and the mixture was stirred using a propeller stirring blade. After holding for 4 hours, the mixture was air-cooled until the temperature reached 25°C. A 10% hydrochloric acid aqueous solution was added to the resulting mixture, the pH was adjusted to 1.5, and the mixture was stirred for 2 hours. Then, it was filtered, washed with water, and dried to obtain toner particles 23. This was designated as toner 23.

[0095] (Manufacturing method for toner 24) The following samples were weighed into a reaction vessel and mixed using a propeller stirring blade. • Toner core particles 1: 100 copies • Release agent-encapsulated particles 17: 58 parts Next, the mixture was heated to 55°C and then kept at that temperature for 1 hour while being mixed using a propeller agitator. Next, the pH of the mixture was adjusted to 5.6, then 3.0 parts of organosilicon compound solution 1 were added and stirred. The pH was then adjusted to 2.5 using a 10% hydrochloric acid aqueous solution, and the mixture was held for 4 hours while being mixed with a propeller stirring blade, after which it was air-cooled until the temperature reached 25°C. A 10% hydrochloric acid aqueous solution was added to the resulting mixture, the pH was adjusted to 1.5, and the mixture was stirred for 2 hours. After that, it was filtered, washed with water, and dried to obtain toner particles 24. These were designated as toner 24.

[0096] [Table 4]

[0097] (Manufacturing method for comparative toner 1) 100 portions of toner core particles 2 were weighed into the reaction vessel and mixed using a propeller stirring blade. Next, the pH of the mixture was adjusted to 5.6, then 2.8 parts of organosilicon compound solution 1 were added and stirred. The pH was then adjusted to 9.6 using a 7.3% sodium bicarbonate aqueous solution, and after holding for 4 hours, it was air-cooled until the temperature reached 25°C. Comparative toner 1 was obtained by adding a 10% hydrochloric acid aqueous solution to the resulting mixture, adjusting the pH to 1.5, stirring for 2 hours, then filtering, washing with water, and drying.

[0098] (Manufacturing method for comparative toner 2) The following samples were weighed into a reaction vessel and mixed using a propeller stirring blade. • Resin-encapsulated particles 18: 58 parts • Toner core particles 2: 100 copies Next, the mixture was heated to 55°C and then kept at that temperature for 1 hour while being mixed using a propeller agitator. Next, the pH of the mixture was adjusted to 5.6, then 2.8 parts of organosilicon compound solution 1 were added and stirred. The pH was then adjusted to 9.6 using a 7.3% sodium bicarbonate aqueous solution, and the mixture was kept in place for 4 hours while being mixed with a propeller stirring blade, before being air-cooled until the temperature reached 25°C. Comparative toner 2 was obtained by adding a 10% hydrochloric acid aqueous solution to the resulting mixture, adjusting the pH to 1.5, stirring for 2 hours, then filtering, washing with water, and drying.

[0099] (Manufacturing method for comparative toner 3) A comparative toner 3 was obtained in the same manner as the manufacturing method of toner 1, except that release agent-encapsulated particles 4 were used.

[0100] (Manufacturing method for comparative toner 4) A comparative toner 4 was obtained in the same manner as the manufacturing method of toner 1, except that release agent-encapsulated particles 3 were used.

[0101] (Manufacturing method for comparative toner 5) A comparative toner 5 was obtained in the same manner as the manufacturing method of toner 1, except that release agent-encapsulated particles 2 were used.

[0102] (Manufacturing method for comparative toner 6) The following samples were weighed into a reaction vessel and mixed using a propeller stirring blade. • Release agent particles 1 0.7 parts • Toner core particles 1,100 copies Next, the mixture was heated to 55°C and then kept at that temperature for 1 hour while being mixed using a propeller agitator. Next, the pH of the mixture was adjusted to 5.6, then 2.8 parts of organosilicon compound solution 1 were added and stirred. The pH was then adjusted to 9.6 using a 7.3% sodium bicarbonate aqueous solution, and the mixture was kept in place for 4 hours while being mixed with a propeller stirring blade, before being air-cooled until the temperature reached 25°C. Comparative toner 6 was obtained by adding a 10% hydrochloric acid aqueous solution to the resulting mixture, adjusting the pH to 1.5, stirring for 2 hours, then filtering, washing with water, and drying.

[0103] (Physical properties of toners 1-24 and comparative toners 1-6) The physical properties of the toners produced in Examples 1-24 and Comparative Examples 1-6 are shown in Table 5 below.

[0104] [Table 5] In the table, "Domain Inclusion" is indicated as "yes" if the release agent domain is included in the shell, and as "no" if it is not included. (Note that in comparative toner 2, resin particles were included. In comparative toner 6, an organosilicon polymer coated the release agent domain on the surface of the toner core particles, but it was not included.) The non-contact percentage is expressed as a percentage of particles. The molecular weight in formula (1) indicates the molecular weight of the fragment ion peak corresponding to the structure shown in formula (1) obtained by TOF-SIMS. The coverage rate is the area percentage (coverage rate: area %) occupied by the organosilicon polymer on the surface of the toner particles.

[0105] (Toner evaluation) The following evaluations were performed using toners 1-24 and comparative toners 1-6. (Evaluation of retention) Low-temperature fixation performance is evaluated by determining the minimum fixing temperature at which no visible image defects occur in the fixed image. Furthermore, visible image defects that occur during low-temperature fixing mainly include cold offset, which occurs when the toner does not melt, and blistering, which occurs when the toner does not melt sufficiently and the adhesion between the toner and the fixing roller is high. A blister is a blister-like image defect that occurs during the fixing process when a portion of the fixed image peels off due to the fixing roller. In the fixed image, it appears as a tiny white patch.

[0106] The temperature at which these image defects occur is lower for cold offset images. As the fixing temperature increases, blistering occurs, and further increases in the fixing temperature result in good images without defects. The evaluation was performed as follows. We prepared a color laser printer (HP Color LaserJet 3525dn, manufactured by HP) with the fuser unit removed, extracted the toner from the black, cyan, and magenta cartridges, and replaced them with 50g each of the toner to be evaluated.

[0107] Next, using the filled toner, an unfixed toner image measuring 2.0 cm vertically and 15.0 cm horizontally was created on the receiving paper (Canon A4 size OceRedLabel paper (basis weight 80 g / m2)) using the filled toner (toner coverage: 1.2 mg / cm²). 2 A portion of the paper was formed 1.0 cm from the top edge in the paper feeding direction. Next, the removed fixing unit was modified to allow adjustment of the fixing temperature and process speed, and this was used to perform fixing tests on unfixed images.

[0108] First, under normal temperature and humidity conditions (23°C, 60%RH), the process speed was set to 230 mm / s, and the initial temperature was set to 155°C. The unfixed images were then fixed at each temperature while the set temperature was sequentially increased by 5°C. For the obtained fixed images, the lowest fixing temperature was defined as the temperature at which no cold offset occurred and there were two or fewer white spots due to blistering. The low-temperature fixing performance was evaluated based on the following criteria. The results are shown in Table 6. A: Minimum fixing temperature is 160°C or lower B: Minimum fixing temperature is 165°C or 170°C C: Minimum fixing temperature is 175°C or 180°C D: Minimum fixing temperature is 185°C or 190°C

[0109] (Evaluation of release properties) In the above adhesion test, the release properties were evaluated according to the following evaluation criteria. High-temperature offset (HO) is a phenomenon in which some toner fuses to the fuser roller during high-temperature fixing. Toners with lower release properties are more prone to this phenomenon at lower fixing temperatures. The evaluation criteria are as follows. The results are shown in Table 6. The highest temperature at which high-temperature offset does not occur is, A: The minimum fixing temperature is 50°C or higher. B: Minimum fixing temperature + 40°C or higher but less than 50°C. C: Minimum fixing temperature + 30°C or higher and less than 40°C. D: The minimum fixing temperature is less than +30°C.

[0110] (Evaluation of material contamination) The following method was used to evaluate material contamination in toners 1-24 and comparative toners 1-6. . First, a color laser printer (LBP-712Ci, Canon) modified to have a process speed of 300 mm / sec was used. Next, the toner from the cyan cartridge was removed, and 100g each of toners 1-24 and comparative toners 1-6 were filled into this cartridge. The following evaluations were then performed.

[0111] Install the above cartridge into the printer's cyan station and test it under normal temperature and humidity conditions (temperature 23°C, humidity 60%RH) using A4 size plain paper Office 70 (Canon Marketing Japan, 70g / m²). 2 Using a 0.2% print density chart, one image was printed. Then, the process of printing two images and stopping for 10 seconds was repeated, and while replenishing toner, the developing blade and developing roller were visually inspected every 1000 images to check for toner fusion. The number of prints in which resin fusion occurred was used as an indicator, and component contamination was evaluated according to the following criteria. The results are shown in Table 6. A: No fusion occurred in either the developing blade or developing roller up to 16,000 sheets. B: Fusion occurs on the developing blade and developing roller between 10,000 and 16,000 sheets. C: Fusion occurs on the developing blade and developing roller between 5,000 and 10,000 sheets. D: Fusion occurs on the developing blade and developing roller after 5000 sheets.

[0112] (Evaluation of toners 1-24 and comparative toners 1-6) Table 6 shows the evaluation results of the toners prepared in Examples 1-24 and Comparative Examples 1-6.

[0113] [Table 6]

[0114] This disclosure relates to the following configuration. (Composition 1) A toner having toner core particles and toner particles having a shell that covers the toner core particles, The shell contains an organosilicon polymer, The shell contains domains of the release agent, In cross-sectional observation of the toner particles using a transmission electron microscope, the release agent is observed. The proportion of domains of the release agent that are not in contact with the toner core particles out of the total number of particles is 85% or more. A toner characterized by the following features. (Configuration 2) The toner according to configuration 1, wherein the mold release agent is a hydrocarbon wax. (Composition 3) The toner according to configuration 2, wherein, by depth profile analysis of the toner particles using time-of-flight secondary ion mass spectrometry, fragment ion peaks corresponding to the structure shown in formula (1) below are obtained in the region corresponding to the domain of the release agent, in the molecular weight range of 400 to 600. TIFF2023176349000009.tif29153 (configuration 4) The toner according to any one of configurations 1 to 3, wherein, in cross-sectional observation of the toner particles using a transmission electron microscope, the average value of the shortest distance D from the surface of the toner particles to the domain of the release agent is 5 to 50 nm. (Composition 5) The toner according to any one of configurations 1 to 4, wherein, in cross-sectional observation of the toner particles using a transmission electron microscope, the ratio of the total area S2 of the domains of the release agent to the area S1 occupied by the toner core particles (S2 / S1 × 100) is 0.05 to 5.00 area%. (Composition 6) The toner according to any one of configurations 1 to 5, wherein the area ratio occupied by the organosilicon polymer on the surface of the toner particles is 35 to 75 area%. (Configuration 7) The toner according to any one of Configurations 1 to 6, wherein the organosilicon polymer is a polycondensate of at least one compound selected from the group consisting of an organosilicon compound represented by the following formula (2), an organosilicon compound represented by the following formula (3), and an organosilicon compound represented by the following formula (4). TIFF2023176349000010.tif109153(In the above formulas (2), (3) and (4), R a and R b each independently represent an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 1 to 8 carbon atoms, or a phenyl group. R 1 , R 2 , R 3 and R 4 each independently represent a halogen atom or an alkoxy group having 1 to 8 carbon atoms.) (Configuration 8) The toner according to any one of Configurations 1 to 7, wherein the shell is the organosilicon polymer that encloses the domain of the release agent.

Claims

1. A toner having toner particles having a toner core particle and a shell covering the toner core particle, the shell comprises an organosilicon polymer; the shell encapsulates domains of a release agent; When a cross section of the toner particle is observed using a transmission electron microscope, the ratio of domains of the release agent that are not in contact with the toner core particle to the total number of domains of the release agent observed is 85% or more by number. A toner characterized by:

2. 2. The toner according to claim 1, wherein the release agent is a hydrocarbon wax.

3. 3. The toner according to claim 2, wherein a fragment ion peak corresponding to a structure represented by the following formula (1) is obtained in a molecular weight range of 400 to 600 in a region corresponding to a domain of the release agent by depth profile analysis using time-of-flight secondary ion mass spectrometry on the toner particles:

4. 4. The toner according to claim 1, wherein, in cross-sectional observation of the toner particles with a transmission electron microscope, an average value of the shortest distance D from the surface of the toner particles to the domain of the release agent is 5 to 50 nm.

5. 4. The toner according to claim 1, wherein, in cross-sectional observation of the toner particle with a transmission electron microscope, a ratio (S2 / S1×100) of a total area S2 of domains of the release agent to an area S1 occupied by the toner core particle is 0.05 to 5.00 area %.

6. 4. The toner according to claim 1, wherein the area ratio of the organosilicon polymer to the surface of the toner particles is 35 to 75 area %.

7. The toner according to any one of claims 1 to 3, wherein the organosilicon polymer is a condensation polymer of at least one compound selected from the group consisting of organosilicon compounds represented by the following formula (2), organosilicon compounds represented by the following formula (3), and organosilicon compounds represented by the following formula (4): (In the above formulas (2), (3) and (4), R ａ and R ｂ R each independently represents an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 1 to 8 carbon atoms, or a phenyl group. １ , R ２ , R ３ and R ４ each independently represents a halogen atom or an alkoxy group having 1 to 8 carbon atoms.

8. 4. The toner according to claim 1, wherein the shell is the organosilicon polymer encapsulating domains of the release agent.

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