JP7614786B2 - Method for producing toner additive and method for producing toner - Google Patents

Description

The present invention relates to a method for producing particles and a method for producing toner.

In recent years, there has been a demand for higher image quality and faster printing speeds in image forming devices that use electrophotography. In response to these demands, various toner materials are being investigated to obtain high image quality even in high-speed printing.

Patent Document 1 discloses a method for producing organic-inorganic composite particles having an organic polymer skeleton and a polysiloxane skeleton as a toner additive. It discloses that the inclusion of the toner additive in the toner improves the transfer properties of the toner.

Japanese Patent Application Publication No. 9-197706

As a result of the inventors' investigation of the toner produced by the method described in Patent Document 1, they recognized that further improvement is required in terms of the charge amount of the toner and the change over time in the charge amount of the toner when continuous image output is performed.

The present invention aims to provide a method for producing particles that can produce toner that can have a high charge amount and whose charge amount is unlikely to change over time even when continuous image output is performed, that is, toner that can have excellent charge retention. The present invention also aims to provide a method for producing toner that can have excellent charge retention.

The present invention provides a method for producing particles, comprising the steps of:
The manufacturing method comprises:
A radical polymerization step of carrying out a radical polymerization reaction of a monomer raw material containing a compound represented by the following formula (1) under a condition of 6.0≦pH≦8.0;
R ¹ _m SiX _4-m ... (1)
(In formula (1), X is a hydrolyzable group, m is an integer of 1 to 3, each R ¹ is independently an organic group having 1 to 20 carbon atoms, and at least one R ¹ is a radical polymerizable group having 1 to 20 carbon atoms.)
a condensation step in which, after the radical polymerization step, a hydrolysis reaction of a hydrolyzable group in the compound and a polycondensation reaction are carried out to obtain polycondensate particles; and a hydrophobization step in which the polycondensate particles are hydrophobized with an alkylsilylation agent.
The present invention relates to a method for producing particles, the method comprising the steps of:

Also, one aspect of the present invention is a method for producing a particle by the particle production method according to the present invention;
adding the produced particles to toner particles;
A method for producing a toner comprising the steps of:

The present invention provides a method for producing particles that can produce toner that has a high charge amount and excellent charge retention. It also provides a method for producing toner to which the particles are externally added.

When a numerical range is expressed as "xx or more and xx or less" or "xx to xx", it means that the numerical range includes the lower and upper limit endpoints, unless otherwise specified.

When numerical ranges are stated in stages, the upper and lower limits of each numerical range can be combined in any way.

The particles according to the present invention are preferably particles for toner, and more preferably external additives for toner. The particles are also preferably organic-inorganic composite particles. Organic-inorganic composite particles refer to particles that have organic and inorganic components at the molecular level.

<Causes of insufficient charge amount and charge retention>
The present inventors consider the reason why further improvement in the charge amount and charge retention of the toner to which the toner additive produced by the production method according to Patent Document 1 is externally added to be necessary as follows.

The particles produced by the method for producing a toner additive in Patent Document 1 may not have sufficient hydrophobicity on the particle surface, resulting in insufficient charge amount and charge retention of the toner. This is thought to be because vinyl polymerization is carried out after hydrolysis and polycondensation of the hydrolyzable groups bonded to silicon, so there is thought to be a resin portion on the particle surface, but some of the remaining silanol structures are easily exposed, and charge is likely to leak from these portions.

It was also found that when a toner additive in which the above particles have been hydrophobized with an alkyl silylating agent in order to improve the degree of hydrophobization is added to the toner, the charge retention is insufficient. The inventors speculate that this is because, since vinyl polymerization is carried out later, it is difficult for reaction sites (such as hydroxyl groups) that can chemically bond with the alkyl silylating agent acting as a hydrophobizing agent to exist on the particle surface, and therefore sufficient hydrophobization is not achieved.

As a result of intensive research, the inventors have found that a toner to which particles produced by the manufacturing method having the above-mentioned constituent elements are externally added can have a high charge amount and is likely to have excellent charge retention. The speculated mechanism and each of the constituent elements are explained in detail below.

<Mechanism by which the effects of the present invention are manifested>
The present inventors consider the mechanism by which the effects of the present invention are manifested as follows.

By carrying out a radical polymerization reaction of a monomer raw material containing a monomer having a hydrolyzable group and a radically polymerizable group under the condition of 6.0≦pH≦8.0, radical polymerization occurs in a state where the hydrolysis reaction is difficult to proceed, and molecular chains of vinyl resin are formed.

In addition, by subsequently carrying out the hydrolysis reaction and polycondensation reaction of the hydrolyzable groups to obtain particles, it is believed that it is easy to form a polysiloxane skeleton in the particles in a state in which the particle surface is likely to have reaction sites that can be hydrophobized with an alkyl silylating agent. As a result, it is easy to obtain particles that are not easily plastically deformed, and frictional charging is easily generated between the particles and toner particles, so that toners to which the particles are externally added can have a high charge amount.

Furthermore, by subjecting the particles to hydrophobic treatment with an alkyl silylation agent, the agent reacts with the above-mentioned reaction sites, which tends to increase the hydrophobicity of the particle surface, and toner to which the particles are externally added can have a high charge amount and excellent charge retention.

<Method of producing particles>
The method for producing the particles is carried out through the following steps (1) to (3).
(1) A radical polymerization step in which radical polymerization of a monomer raw material containing a compound represented by the following formula (1) is carried out under near-neutral conditions; (2) A condensation step in which a hydrolysis reaction for hydrolyzing hydrolyzable groups in the system and a polycondensation reaction are carried out to obtain polycondensate particles; (3) A hydrophobization step in which the surface of the particles is hydrophobized with an alkylsilylation agent. <Radical polymerization step>
The radical polymerization step is a step of carrying out a radical polymerization reaction of a monomer raw material containing a compound represented by the following formula (1) under the condition of 6.0≦pH≦8.0.

The method for carrying out the radical polymerization reaction in the radical polymerization process is preferably the emulsion polymerization method.

The emulsion polymerization method is a polymerization method in which a medium such as water is mixed with a monomer that is poorly soluble in the medium and an emulsifier (surfactant) or an ionic comonomer, and a polymerization initiator (usually a radical generator) that is soluble in the medium is added to the mixture. The above emulsion polymerization method may be a soap-free emulsion polymerization method that does not use a surfactant.

The radical polymerization process is a process in which a radical polymerization reaction is carried out on a monomer raw material containing a compound represented by the following formula (1):

R ¹ _m SiX _4-m ... (1)
In formula (1), X is a hydrolyzable group, m is an integer of 1 to 3, each R ¹ is independently an organic group having 1 to 20 carbon atoms, and at least one R ¹ is It is a radical polymerizable group having 1 to 20 carbon atoms.
More preferably, R ¹ is an organic group having 1 to 15 carbon atoms, and even more preferably, R ¹ is an organic group having 1 to 10 carbon atoms.

The monomer raw material refers to a monomer having a radically reactive double bond in its structure. The monomer may be one type or multiple types.

The content of the compound represented by the above formula (1) in the monomer raw material is preferably 60.0 to 100.0% by mass. This is preferable because a content within the above range is believed to facilitate the formation of a sufficient amount of polysiloxane skeleton in the particles and facilitate the presence of sufficient reaction sites capable of alkylsilylation on the particle surface of the polycondensate.

The above hydrolyzable group means a functional group or a hydroxy group that is converted to a hydroxy group after hydrolysis of the above compound.

The type of hydrolyzable group includes at least one substituent selected from the group consisting of a hydroxy group, a halogen functional group, an alkoxy group, and an acyloxy group. Among the above, an alkoxy group or an acetoxy group is preferable, and at least one substituent selected from the group consisting of a methoxy group, an ethoxy group, a propoxy group, and an acetoxy group is more preferable. When these hydrolyzable groups are hydrolyzed, the above compounds have a silanol structure, which is preferable because it is believed that it is easy to form a polysiloxane skeleton by polycondensation from there.

In addition, a radically polymerizable group means a substituent having a radically reactive double bond in its structure.

The radical polymerizable group is preferably a substituent represented by the following formula (2):

(In formula (2), ^R2 is hydrogen or a methyl group, and ^R3 is an alkylene group having 1 to 10 carbon atoms.)
The compound represented by formula (1) having the radical polymerizable group represented by formula (2) is highly reactive in the radical polymerization process, and it is considered that the radical polymerization is likely to proceed before the hydrolysis and polycondensation reactions proceed under neutral conditions. As a result, it is considered that the hydrolysis and polycondensation reactions proceed after the radical polymerization reaction has sufficiently progressed, and therefore it is possible to leave reaction sites on the surface of the obtained particles that can be hydrophobized by the alkylsilylation agent.

Specific examples of the compound represented by the above formula (1), that is, the monomer containing both a radically polymerizable group and a hydrolyzable group, include the following.
Organotrialkoxysilane compounds such as γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-acryloxypropyltrimethoxysilane, γ-acryloxypropyltriethoxysilane, γ-methacryloxypropyltriacetoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, 1-hexenyltrimethoxysilane, and 1-octenyltrimethoxysilane, organotriacetoxysilane, bis(γ-acryloxypropyl)dimethoxysilane, bis(γ-methacryloxypropyl)dimethoxysilane, γ-methacryloxypropylethyldimethoxysilane, γ-methacryloxypropylethyldiethoxysilane, and γ-acryloxypropyl Diorganodialkoxysilane compounds such as pylethyldimethoxysilane and γ-acryloxypropylethyldiethoxysilane, tris(γ-acryloxypropyl)methoxysilane, tris(γ-acryloxypropyl)ethoxysilane, tris(γ-methacryloxypropyl)methoxysilane, tris(γ-methacryloxypropyl)ethoxysilane, bis(γ-acryloxypropyl)vinylmethoxysilane, bis(γ-methacryloxypropyl)vinylmethoxysilane, γ-acryloxypropyldiethylmethoxysilane, γ-acryloxypropyldiethylethoxysilane, γ-methacryloxypropyldiethylmethoxysilane, triorganoalkoxysilane compounds such as γ-methacryloxypropyldiethylethoxysilane, etc. These may be used alone or in combination of two or more.

Among the above monomers, particularly preferred are γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-acryloxypropyltrimethoxysilane, γ-acryloxypropyltriethoxysilane, γ-methacryloxypropyltriacetoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, and vinyltriacetoxysilane.

The radical polymerization process is carried out under the condition of 6.0≦pH≦8.0. More preferably, 6.5≦pH≦7.5. The reason for this is that in the radical polymerization process, the more the pH is away from neutral, the more easily hydrolysis of hydrolyzable groups and polycondensation reactions proceed in the radical polymerization reaction. As a result, it is believed that the number of reaction sites on the particle surface that bond with the alkyl silylating agent is more likely to decrease. For this reason, it is preferable to carry out the radical polymerization reaction in a buffer solution. There are no particular limitations on the type of buffer solution as long as it has a pH close to neutral, but preferred buffer solutions are phosphate buffer and 2-morpholinoethanesulfonic acid buffer (MES buffer).

In addition, in the radical polymerization reaction, a monomer not corresponding to the above formula (1) may be contained in the monomer raw material, for example, the following:

Unsaturated carboxylic acids such as acrylic acid and methacrylic acid, unsaturated carboxylic acid esters such as acrylic acid esters, methacrylic acid esters, crotonates, itaconic acid esters, maleic acid esters, and fumaric acid esters, acrylamides, methacrylamides, aromatic vinyl compounds such as styrene, α-styrene, and divinylbenzene, vinyl esters such as vinyl acetate, and vinyl halide compounds such as vinyl chloride. These may be used alone or in combination of two or more. Monomers containing two or more radically polymerizable groups such as divinylbenzene, trimethylolpropane trimethacrylate, and ethylene glycol dimethacrylate may also be used. Among the above, it is particularly preferable to include styrene in the monomer raw material from the viewpoint of stable particle formation and the surface properties of the particles formed. In addition, the content of styrene in the monomer raw material is preferably 20.0 to 40.0% by mass.

<Radical Polymerization Initiator>
The radical polymerization initiator used in the radical polymerization is not particularly limited, but is preferably at least one compound selected from azo compounds, peroxides, and the like. The amount of the radical polymerization initiator is not particularly limited, but is preferably 0.1 to 10% by mass relative to the total mass of the raw material monomers in order to sufficiently advance the radical polymerization reaction and to easily control the reaction heat. More preferably, it is 0.3 to 5% by mass. The temperature during radical polymerization can be appropriately selected depending on the radical polymerization initiator used, but is in the range of 30 to 100°C, preferably 50 to 70°C, in view of ease of reaction control.

<Condensation step>
The condensation step is a step in which, after the radical polymerization step, a hydrolysis reaction of the hydrolyzable groups in the compound represented by the above formula (1) and a polycondensation reaction are carried out to obtain polycondensate particles.

In the above process, a catalyst such as an acid or base may be added to the emulsion containing the particles obtained by radical polymerization, and hydrolysis and polycondensation may be performed directly. Alternatively, the particles obtained by radical polymerization may be isolated from the emulsion using a method such as filtration, centrifugation, or vacuum concentration, and then a catalyst may be added to perform hydrolysis and polycondensation, but this is not limited to these methods. In other words, the above radical polymerization process may be a process in which a radical polymerization reaction of a monomer raw material is performed to obtain polymer particles.

In addition, it is preferable to use water as a reaction solvent for the hydrolysis step and the polycondensation step, since it is believed that the hydrolysis reaction proceeds easily and that the surface of the polycondensate particles tends to contain many hydroxyl groups.

The reaction solvent may contain an organic solvent other than water and the catalyst. Specific examples of organic solvents include alcohols such as methanol, ethanol, isopropanol, n-butanol, isobutanol, sec-butanol, t-butanol, pentanol, ethylene glycol, propylene glycol, and 1,4-butanediol; ketones such as acetone and methyl ethyl ketone; esters such as ethyl acetate; (cyclo)paraffins such as isooctane and cyclohexane; ethers such as dioxane and diethyl ether; and aromatic hydrocarbons such as benzene and toluene. These may be used alone or in combination of two or more.

The hydrolyzable group in the compound represented by the above formula (1) is considered to be easily hydrolyzed under acidic conditions. In addition, the structure obtained by hydrolyzing the compound represented by the above formula (1), i.e., the silyl alcohol structure, is considered to be easily polycondensed under basic conditions. That is, it is preferable that the condensation step has a step A in which the reaction is carried out under acidic conditions, and a step B in which the reaction is carried out under basic conditions after the step A. It is more preferable that the condensation step has a step A in which the reaction is carried out under conditions of 2.0≦pH≦4.0, and a step B in which the reaction is carried out under conditions of 10.0≦pH≦12.0 after the step A.

Catalysts used in hydrolysis and polycondensation reactions include acetic acid, hydrochloric acid, ammonia, urea, ethanolamine, tetramethylammonium hydroxide, alkali metal hydroxides, and alkaline earth metal hydroxides.

The above-mentioned catalysts may be used to promote the polycondensation reaction, but preferred catalysts in terms of further promoting condensation include organic titanium compounds such as titanium tetraisopropoxide, titanium tetrabutoxide, and diisopropoxy-bis(acetylacetonate) titanate, organic aluminum compounds such as aluminum triisopropoxide, aluminum trisec-butoxide, aluminum trisacetylacetonate, and aluminum isopropoxide-bisacetylacetonate, organic zirconium compounds such as zirconium tetrabutoxide and tetrakis(acetylacetonate) zirconium, organic tin compounds such as dibutyltin diacetate, dibutyltin diethylhexanoate, and dibutyltin dimaleate, and acidic phosphate esters. These may be used alone or in combination of two or more. Among them, at least one selected from the group consisting of organic tin compounds and acidic phosphate esters is preferred.

The reaction temperature for the hydrolysis and polycondensation reactions is preferably in the range of 0 to 100°C, and more preferably in the range of 30 to 80°C. The reaction time is preferably in the range of 3 to 24 hours.

<Hydrophobizing step>
The hydrophobization step is a step of hydrophobizing the polycondensate particles with an alkylsilylating agent. In this step, an alkylsilylating agent may be added to an emulsion containing the polycondensate particles obtained by polycondensation while the catalyst such as acid or base from the hydrolysis and polycondensation reaction remains, and the polycondensate particles may be alkylsilylated as they are. Alternatively, the particles obtained by polycondensation may be isolated from the emulsion by a method such as filtration, centrifugation, or vacuum concentration, and then an alkylsilylating agent dissolved in an organic solvent may be added to the emulsion to alkylsilylate the particles. Alternatively, the alkylsilylating agent may be generated as vapor, and the particles isolated from the emulsion may be exposed to the vapor to alkylsilylate the particles, but is not limited thereto.

Examples of alkyl silylating agents include the following:

Hexamethyldisilazane, hexamethyldisilazane, trimethylsilanol, methoxytrimethylsilane, dimethoxydimethylsilane, trimethoxymethylsilane, ethoxytrimethylsilane, diethoxydimethylsilane, triethoxymethylsilane, chlorotrimethylsilane, dichlorodimethylsilane, trichloromethylsilane, decyltrimethoxysilane, dodecyltrimethoxysilane, hexadecyltrimethoxysilane, decyltriethoxysilane, dodecyltriethoxysilane, hexadecyltriethoxysilane, octyltrimethoxysilane, isobutyltrimethoxysilane, trimethylsilane, trimethylethoxysilane , allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilylmercaptan, trimethylsilylmercaptan, triorganosilylacrylate, vinyldimethylacetoxysilane, dimethylethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, N,O-bis(trimethylsilyl)acetamide, N-trimethylsilylimidazole, and N,O-bis(trimethylsilyl)trifluoroacetamide.

These may be used alone or in combination of two or more.

Among the above, at least one selected from the group consisting of hexamethyldisilazane, trimethylsilanol, methoxytrimethylsilane, dimethoxydimethylsilane, trimethoxymethylsilane, chlorotrimethylsilane, dichlorodimethylsilane, trichloromethylsilane, decyltrimethoxysilane, dodecyltrimethoxysilane, and hexadecyltrimethoxysilane is more preferred.

Catalysts used in the alkylsilylation reaction include acetic acid, hydrochloric acid, ammonia, urea, ethanolamine, pyridine, tetramethylammonium hydroxide, alkali metal hydroxides, alkaline earth metal hydroxides, etc.

The temperature for carrying out the alkylsilylation treatment of the particle surface is preferably in the range of 0 to 100°C, and more preferably in the range of 50 to 70°C. The treatment time is preferably in the range of 3 to 24 hours.

<Toner>
Moreover, the particles according to the present invention are preferably contained on the surface of toner particles. That is, one aspect of the present invention is preferably a method for producing a toner, which includes a step of producing particles by the method for producing particles according to the present invention, and a step of externally adding the produced particles to toner particles. That is, the particles according to the present invention are preferably an external additive for toner. Furthermore, in order to obtain an appropriate volume average particle size when externally added to a toner, when the 50% particle size based on the volume distribution of the particles according to the present invention is taken as D50, it is preferable that the D50 is 60 to 250 nm.

The surface of the toner particles may contain particles other than the particles according to the present invention. Such particles include charge control agents and fluidizing agents, and it is particularly preferable to contain a fluidizing agent in order to improve the fluidity and chargeability of the toner. Examples of charge control agents and fluidizing agents are described below.

The toner particles preferably contain a binder resin. Examples of the binder resin include polyester resins, vinyl resins, epoxy resins, and polyurethane resins.

From the viewpoint of storage stability, it is preferable that the binder resin has a glass transition point (Tg) of 45 to 70°C.

<Method of Manufacturing Toner Particles>
The method for producing the toner particles according to the present invention is not particularly limited, and for example, a pulverization method or a polymerization method such as an emulsion polymerization method, a suspension polymerization method, or a solution suspension method can be used.

In the pulverization method, first, the binder resin, colorant, wax, charge control agent, etc. that make up the toner particles are thoroughly mixed using a mixer such as a Henschel mixer or ball mill. The resulting mixture is then melted and kneaded using a thermal kneader such as a twin-screw kneading extruder, heated roll, kneader, or extruder, and after cooling and solidifying, the mixture is pulverized and classified to obtain toner particles.

Examples of kneading machines include the following: KRC kneader (manufactured by Kurimoto Iron Works); Buss-Co kneader (manufactured by Buss); TEM type extruder (manufactured by Toshiba Machine); TEX twin-screw kneader (manufactured by Japan Steel Works); PCM kneader (manufactured by Ikegai Iron Works); three-roll mill, mixing roll mill, kneader (manufactured by Inoue Seisakusho); Kneadex (manufactured by Mitsui Mining Co., Ltd.); MS-type pressure kneader, kneader ruder (manufactured by Nippon Spindle); Banbury mixer (manufactured by Kobe Steel, Ltd.).

Examples of pulverizers include the following: Counter Jet Mill, Micron Jet, Innomizer (manufactured by Hosokawa Micron Corporation); IDS type mill, PJM jet pulverizer (manufactured by Nippon Pneumatic Mfg. Co., Ltd.); Cross Jet Mill (manufactured by Kurimoto Iron Works); Urmax (manufactured by Nisso Engineering Co., Ltd.); SK Jet-O-Mill (manufactured by Seishin Enterprise Co., Ltd.); Kryptron (manufactured by Kawasaki Heavy Industries, Ltd.); Turbo Mill (manufactured by Turbo Industrial Co., Ltd.); Super Rotor (manufactured by Nisshin Engineering Co., Ltd.).

Classifiers include the following: Classeal, Micron Classifier, and Spedic Classifier (manufactured by Seishin Enterprises); Turbo Classifier (manufactured by Nisshin Engineering); Micron Separator, Turboplex (ATP), and TSP Separator (manufactured by Hosokawa Micron); Elbow Jet (manufactured by Nittetsu Mining Co., Ltd.), Dispersion Separator (manufactured by Nippon Pneumatic Industry Co., Ltd.); and YM Microcut (manufactured by Yaskawa Shoji Co., Ltd.).

In the suspension polymerization method, first, the polymerizable monomer, which is the material of the binder resin, and various additives as necessary are mixed, and a monomer composition is prepared by dissolving or dispersing these using a disperser. Examples of various additives include colorants, waxes, charge control agents, polymerization initiators, and chain transfer agents. Examples of dispersers include homogenizers, ball mills, colloid mills, and ultrasonic dispersers. Next, the monomer composition is put into an aqueous medium containing poorly water-soluble inorganic fine particles, and droplets of the monomer composition are prepared using a high-speed disperser such as a high-speed stirrer or ultrasonic disperser (granulation process). After that, the polymerizable monomer in the droplets is polymerized to obtain toner particles (polymerization process). The polymerization initiator may be mixed when preparing the monomer composition, or may be mixed into the monomer composition immediately before forming droplets in the aqueous medium. In addition, the polymerization initiator may be added in a dissolved state in the polymerizable monomer or another solvent during or after the granulation of the droplets is completed, i.e., immediately before starting the polymerization reaction, as necessary. After the polymerizable monomer is polymerized to obtain the binder resin, a solvent removal process can be performed as necessary to obtain the toner particles.

<Toner Manufacturing Method>
The toner according to the present invention can be obtained by thoroughly mixing the particles according to the present invention and desired external additives including a fluidizing agent together with toner particles in a mixer such as a Henschel mixer.

Examples of mixers include the following: Henschel Mixer (manufactured by Mitsui Mining Co., Ltd.); Super Mixer (manufactured by Kawata Co., Ltd.); Ribocone (manufactured by Okawara Manufacturing Co., Ltd.); Nauta Mixer, Turbulizer, Cyclomix (manufactured by Hosokawa Micron Co., Ltd.); Spiral Pin Mixer (manufactured by Pacific Machinery Co., Ltd.); Loedige Mixer (manufactured by Matsubo Co., Ltd.).

<Various additives, etc.>
If necessary, the toner may contain one or more additives selected from colorants, waxes, magnetic materials, charge control agents, fluidizing agents, etc. Various additives used in the toner will be specifically described.

<Coloring Agent>
Examples of colorants are given below.

Black colorants include, for example, carbon black, grafted carbon, and those toned to black using the yellow/magenta/cyan colorants shown below. Yellow colorants include compounds such as condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds. Magenta colorants include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. Cyan colorants include copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, and basic dye lake compounds. These colorants can be used alone or in a mixture, or in the form of a solid solution.

The colorant according to the present invention is selected from the viewpoints of hue angle, chroma, brightness, weather resistance, transparency on overhead projectors, and dispersibility in the toner. The amount of the colorant added is 1 part by mass or more and 20 parts by mass or less per 100 parts by mass of the binder resin.

<Wax>
Examples of waxes are given below.

These include low molecular weight polyethylene, low molecular weight polypropylene, polyolefin copolymers, polyolefin wax, microcrystalline wax, paraffin wax, aliphatic hydrocarbon waxes such as Fischer-Tropsch wax, oxides of aliphatic hydrocarbon waxes such as oxidized polyethylene wax, block copolymers of aliphatic hydrocarbon waxes, and oxides thereof.

More specific examples include Viscol 330-P, 550-P, 660-P, TS-200 (Sanyo Chemical Industries), Hiwax 400P, 200P, 100P, 410P, 420P, 320P, 220P, 210P, 110P (Mitsui Chemicals), Sasol H1, H2, C80, C105, C77 (Schumann Sasol), HNP-1, HNP-3, HNP-9, HNP-10, HNP-11, HNP-12 (Nippon Seiro), Unilin 350, 425, 550, 700, Unicid, Unicid 350, 425, 550, 700 (Toyo Petrolite), wood wax, beeswax, rice wax, candelilla wax, and carnauba wax (Cerarica NODA).

<Magnetic material>
The toner may also be used as a magnetic toner by incorporating magnetic particles, in which case the magnetic particles may also function as a colorant.

In the present invention, the magnetic particles contained in the magnetic toner include iron oxides such as magnetite, hematite, and ferrite, metals such as iron, cobalt, and nickel, and alloys and mixtures of these metals with metals such as aluminum, cobalt, copper, lead, magnesium, tin, zinc, antimony, bismuth, calcium, manganese, titanium, tungsten, and vanadium.

These magnetic iron oxide particles preferably have an average particle size of 2 μm or less, more preferably 0.05 μm or more and 0.5 μm or less. The amount contained in the toner is preferably 20 parts by weight or more and 200 parts by weight or less per 100 parts by weight of the binder resin, more preferably 40 parts by weight or more and 150 parts by weight or less per 100 parts by weight of the binder resin.

<Fluidizing agent>
Examples of flow agents include the following:

Fluorine-based resin powders such as vinylidene fluoride fine powder and polytetrafluoroethylene fine powder; fine silica powder such as wet-process silica and dry-process silica, fine titanium oxide powder, fine alumina powder, and treated silica obtained by surface-treating these with silane compounds, titanium coupling agents, and silicone oil; oxides such as zinc oxide and tin oxide; double oxides such as strontium titanate, barium titanate, calcium titanate, strontium zirconate, and calcium zirconate; carbonate compounds such as calcium carbonate and magnesium carbonate, etc.

Among the above, the preferred fluidizing agent is a fine powder produced by the vapor phase oxidation of a silicon halide compound, which is called dry process silica or fumed silica. For example, it utilizes the thermal decomposition oxidation reaction of silicon tetrachloride gas in an oxyhydrogen flame, and the basic reaction formula is as follows:
SiCl ₄ +2H ₂ +O ₂ →SiO ₂ +4HCl
In this manufacturing process, it is also possible to obtain a composite fine powder of silica and another metal oxide by using other metal halide compounds such as aluminum chloride or titanium chloride together with the silicon halide compound, and these are also included in the silica.

It is preferable that the average primary particle size of the fluidizing agent in the particle size distribution based on number is 5 nm or more and 30 nm or less, since this can provide high electrostatic charge and fluidity.

Furthermore, as a fluidizing agent that can be used other than the particles according to the present invention, a treated silica fine powder obtained by hydrophobizing the silica fine powder produced by the gas-phase oxidation of the silicon halogen compound is more preferable. Examples of the hydrophobizing treatment include the methods listed in the hydrophobizing process described above.

<Developer>
The toner may be used as a one-component developer, or may be used in combination with a carrier as a two-component developer.

When used as a two-component developer, the carrier preferably used is, for example, surface-oxidized or unoxidized metals such as iron, nickel, cobalt, manganese, chromium, rare earth elements, and alloys or oxides thereof.

The surfaces of these carrier particles are preferably coated or adhered with a material such as a styrene resin, an acrylic resin, a silicone resin, a fluorine resin, or a polyester.

<Charge Control Agent>
As the charge control agent, an organic metal complex or a chelate compound, which easily interacts with a central metal and an acid group or a hydroxyl group present at the terminal of the binder resin used in the present invention, is effective, such as a monoazo metal complex, an acetylacetone metal complex, or a metal complex or metal salt of an aromatic hydroxycarboxylic acid or an aromatic dicarboxylic acid.

Specific examples that can be used include Spilon Black TRH, T-77, and T-95 (Hodogaya Chemical Co., Ltd.), and BONTRON (registered trademark) S-34, S-44, S-54, E-84, E-88, and E-89 (Orient Chemical Co., Ltd.). Charge control resins can also be used in combination with the charge control agents described above.

<Method for measuring the 50% particle size (D50) based on volume distribution of a fine particle sample>
In the examples, the 50% particle size (D50) based on the volume distribution of the fine particle sample is measured using a dynamic light scattering particle size distribution meter Nanotrac UPA-EX150 (manufactured by Nikkiso Co., Ltd.). Specifically, the range is set to 0.001 μm to 10 μm, and the measurement is performed according to the following procedure.

The measurement sample is dispersed in an aqueous solution, and the dispersion is poured in and stirred. When dispersing the measurement sample, a dispersant may be used if necessary. After stirring, the measurement sample is poured into the above device, and measurements are taken twice to determine the average value.

The measurement conditions are: measurement time 30 seconds, sample particle refractive index 1.49, dispersion medium water, dispersion medium refractive index 1.33.

The volumetric particle size distribution of the measurement sample is measured, and the particle size at which the cumulative volume from the small particle size side in the cumulative volume distribution is 50% from the measurement results is taken as the 50% particle size (D50) based on the volume distribution of each microparticle.

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, "parts" and "%" mean "parts by mass" and "% by mass", respectively.

<Production Example of Particle 1>
Step (1): The following materials were placed in a glass reactor equipped with a thermometer, a pH meter, a reflux condenser, a nitrogen gas inlet tube, and a stirrer.
Phosphate buffer solution (pH = 7.0, prepared from sodium dihydrogen phosphate (dihydrate) and disodium hydrogen phosphate (dodecahydrate) manufactured by Kishida Chemical Co., Ltd.) 200 parts Sodium p-styrenesulfonate (manufactured by Kishida Chemical Co., Ltd.) 0.13 parts 3-(trimethoxysilyl)propyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) 11.0 parts Styrene (manufactured by Tokyo Chemical Industry Co., Ltd.) 4.7 parts Next, the mixture was heated to 65-70°C while passing nitrogen gas through it, and after stirring for 30 minutes, 0.51 parts of potassium peroxodisulfate (KPS) was added, and stirring was continued for 6 hours to form particles. The pH of the reaction system during this process was in the range of 6.7 to 7.3.

Step (2): 0.32 parts of acetic acid (Kishida Chemical Co., Ltd.) was added to the emulsion obtained in this manner, and the pH of the emulsion was adjusted to 3.0, followed by stirring at a temperature of 50°C for 3 hours to hydrolyze the hydrolyzable groups contained in the particles. Next, 25.2 parts of 28% by mass ammonia water (Kishida Chemical Co., Ltd.) was added to adjust the pH of the emulsion to 11.0, and the emulsion was stirred at a temperature of 50°C for 3 hours to polycondense the hydrolyzed hydrolyzable groups. After that, ultrafiltration was performed to remove excess solutes, and concentration/filtration was repeated a total of five times.

Step (3): 27.0 parts of 1,1,1,3,3,3-hexamethyldisilazane (hereinafter also referred to as HMDS, manufactured by Kishida Chemical Co., Ltd.) was added as a hydrophobic treatment agent, and the particle surface was hydrophobized by stirring at a temperature of 50°C for 24 hours. The particles were then dried by spray drying to obtain Particle 1 with a D50 of 130 nm.

<Production Examples of Particles 2 to 5>
Particles 2 to 5 having D50 of 145 nm, 89 nm, 125 nm, and 217 nm, respectively, were obtained in the same manner as in the production example of particle 1, except that the type and amount of the radical polymerizable monomer used was changed as shown in Table 1.

<Production Example of Particle 6>
Particles 6 having a D50 of 256 nm were obtained by the same procedure as in the production example of Particles 1, except that the phosphate buffer was changed to a potassium hydrogen phthalate-sodium hydroxide buffer (pH = 5.4, manufactured by Tokyo Chemical Industry Co., Ltd.). The pH in the radical polymerization step was between 5.3 and 5.9.

<Production Example of Particle 7>
Particles 7 having a D50 of 282 nm were obtained by the same procedure as in the production example of Particles 1, except that the phosphate buffer was changed to a boric acid-potassium chloride-sodium hydroxide buffer (pH = 8.6, manufactured by Tokyo Chemical Industry Co., Ltd.). The pH in the radical polymerization step was between 8.1 and 8.7.

<Production Example of Particle 8>
In a solution of 46.7 parts of 28% by mass ammonia water and 2114 parts of deionized water, 22.1 parts of 3-(trimethoxysilyl)propyl methacrylate, 73.7 parts of methanol (Kishida Chemical Co., Ltd.), and 0.12 parts of 2,2'-azobis(2,4-dimethylvaleronitrile) (V-65, Tokyo Chemical Industry Co., Ltd.) as a polymerization initiator were added to the solution to carry out hydrolysis and condensation of 3-(trimethoxysilyl)propyl methacrylate. Next, the mixture was heated to 70-75°C while passing nitrogen gas through it, and vinyl polymerization was carried out by stirring for 2 hours. Thereafter, ultrafiltration was carried out to remove excess solute, and concentration/filtration was repeated a total of 5 times. As a hydrophobic treatment agent, 53.9 parts of HMDS (Kishida Chemical Co., Ltd.) were added, and the mixture was stirred at a temperature of 50°C for 24 hours to hydrophobize the particle surface. Then, the mixture was dried by spray drying to obtain particles 8 having a D50 of 120 nm.

<Production Example of Particle 9>
Particles 9 having a D50 of 129 nm were obtained in the same manner as in the production example of particles 1, except that in step (3), 27.0 parts of HMDS was changed to 31.7 parts of dimethyl silicone oil (KF-96-50CPS, manufactured by Shin-Etsu Chemical Co., Ltd.).

<Production Example of Particle 10>
Particles 10 having a D50 of 131 nm were obtained by carrying out the same procedure as in the production example of Particles 1, except that the hydrophobization treatment step (3) was not carried out.

The manufacturing conditions and D50 of particles 1 to 10 are shown in Table 1.

The abbreviations in Table 1 are as follows.
MA-TMSP: 3-(trimethoxysilyl)propyl methacrylate MA-TESP: 3-(triethoxysilyl)propyl methacrylate AA-TMSP: 3-(trimethoxysilyl)propyl acrylate VTMS: vinyltrimethoxysilane St: styrene KPS: potassium peroxodisulfate V-65: 2,2'-azobis(2,4-dimethylvaleronitrile)
HMDS: 1,1,1,3,3,3-hexamethyldisilazane D50 in Table 1 was measured by the above-mentioned measurement method.

<Production Example of Toner Particle 1>
A premix was obtained by premixing 100 parts of amorphous polyester 1 described below, 75 parts of magnetic iron oxide particles, 2 parts of Fischer-Tropsch wax (C105 manufactured by Sasol, melting point: 105°C), and 2 parts of a charge control agent (T-77 manufactured by Hodogaya Chemical Co., Ltd.) in a Henschel mixer. Thereafter, the premix was melt-kneaded using a twin-screw extruder (product name: PCM-30, manufactured by Ikegai Iron Works Co., Ltd.) with the temperature set so that the molten temperature at the discharge port was 150°C.
Amorphous polyester 1: polycondensate of propylene oxide adduct of bisphenol A/terephthalic acid=50/50, number average molecular weight: 3000, acid value: 12
The obtained kneaded product was cooled, coarsely pulverized with a hammer mill, and then finely pulverized with a pulverizer (product name: Turbo Mill T250, manufactured by Turbo Kogyo Co., Ltd.) The obtained finely pulverized powder was classified with a multi-division classifier utilizing the Coanda effect to obtain toner particles 1 having a weight average particle size of 7.2 μm.

<Production Example of Toner 1>
The external addition of particles to toner particles 1 was performed by a dry method. 100 parts of toner particles 1, 3 parts of particles 1, and 1.5 parts of fumed silica (BET specific surface area: 200 ^m2 /g) were added to a Henschel mixer and externally mixed. After that, the mixture was sieved through a mesh with an opening of 150 μm to obtain toner 1 in which particles 1 were externally added to toner particles 1.

<Production Examples of Toners 2 to 10>
Toners 2 to 10 were obtained in the same manner as in the production example of toner 1, except that particles 1 in the production example of toner 1 were changed as shown in Table 2.

Example 1
The toner 1 was used to carry out the following evaluations.

<Evaluation of Toner Charge Amount>
As an evaluation sample, 1 g of toner 1 and 9 g of ferrite carrier (average particle size 42 μm) surface-coated with silicone resin were weighed into a plastic bottle and left to stand for 24 hours in an environment of temperature 23° C. and humidity 55% RH. After that, using a shaker (YS-LD, manufactured by Yayoi Co., Ltd.), the bottle was shaken for 30 minutes at a speed of 150 reciprocations per minute in an environment of temperature 23° C. and humidity 55% RH to prepare a two-component developer consisting of toner and carrier, and toner 1 was charged.

The charge amount of Toner 1 was measured using an Espart analyzer manufactured by Hosokawa Micron Corporation. The above two-component developer was introduced as sample particles into the measurement section of the Espart analyzer, and the charge amount of Toner 1 was measured. The evaluation results are shown in Table 3. Toners with a charge amount of -25 μC/g or less were judged to have achieved the effects of the present invention.

The Espart Analyzer is a device that introduces sample particles into a detection section (measurement section) that simultaneously forms an electric field and an acoustic field, and measures the particle size and charge by measuring the particle movement speed using the laser Doppler method. The sample particles that enter the measurement section of the device are affected by the acoustic and electric fields, and fall while biased horizontally, and the beat frequency of this horizontal speed is counted. The count value is input to a computer as an interrupt, and the particle size distribution or charge distribution per unit particle size is displayed on the computer screen in real time. Once the charge amount of a specified number of particles has been measured, the screen stops, and the three-dimensional distribution of charge amount and particle size, charge amount distribution by particle size, average charge amount (coulomb/mass), etc. are then displayed on the screen.

<Evaluation of Toner Charge Retention>
The charge retention of the toner was evaluated after the above evaluations.

An HP LaserJet Enterprise M609dn (manufactured by HP) was used as the image forming apparatus, toner 1 was placed in a cartridge, and 5,000 images were output under the following conditions.
・Environment: Temperature 23℃/Humidity 55%RH
Paper: GFC-081 (81.0 g/m ² ) (Canon Marketing Japan Inc.)
Toner loading on paper: 0.35 mg/ ^cm2
Process speed: 377 mm/sec. After that, the residual toner in the cartridge was removed, and the charge amount of the residual toner was measured in the same manner as above, and this value was taken as the charge amount of the toner after durability testing. The value obtained in the evaluation of the charge amount of the toner above was taken as the charge amount of the toner before durability testing, and the fluctuation rate shown in the following formula was calculated, and this value was used to evaluate the charge retention of the toner.

Fluctuation rate (%)=(charge amount of toner before durability test−charge amount of toner after durability test)/charge amount of toner before durability test×100
A rate of change of 20% or less was determined to be one in which the effects of the present invention were obtained.

<Examples 2 to 5, Comparative Examples 1 to 5>
The same evaluation as in Example 1 was carried out using Toners 2 to 10. The evaluation results are shown in Table 3.

Claims (4)

A method for producing an external toner additive , comprising the steps of:
The manufacturing method comprises:
6. A radical polymerization step of carrying out a radical polymerization reaction of a monomer raw material containing any one compound selected from the group consisting of 3-(trimethoxysilyl)propyl methacrylate, 3-(triethoxysilyl)propyl methacrylate, 3-(trimethoxysilyl)propyl acrylate, and vinyltrimethoxysilane under a condition of 5≦pH≦7.5 ;
a condensation step in which, after the radical polymerization step, a hydrolysis reaction of a methoxy group or an ethoxy group, which is a hydrolyzable group in the compound, and a polycondensation reaction are carried out to obtain polycondensate particles; and a hydrophobization step in which the polycondensate particles are hydrophobized with hexamethyldisilazane .
2. A method for producing an external toner additive, comprising: The method for producing an external toner additive according to claim 1 , wherein in the radical polymerization step, the monomer raw material further contains styrene. 3. The method for producing an external toner additive according to claim 1, wherein the condensation step comprises: a step A in which a reaction is carried out under a condition of 2.0≦pH≦4.0; and a step B, after the step A, in which a reaction is carried out under a condition of 10.0≦pH≦12.0. A step of producing an external toner additive by the method for producing an external toner additive according to any one of claims 1 to 3 ;
adding the produced toner additive to toner particles;
A method for producing a toner comprising the steps of: