Method for producing additive particles

Abstract

To provide an external additive particle capable of providing a toner possibly having an excellent fluidity, the fluidity unlikely to change even if continuous image outputs are executed, and a method for producing the same.SOLUTION: A method for producing an external additive particle containing a polymer includes: a radical polymerization process of conducting a radical polymerization reaction of a monomer raw material containing a chemical compound expressed by a formula (3) below, using a radical polymerization initiator having a carboxyl group, under a condition of 6.0≤pH≤8.0; and a condensation process of obtaining a particle containing a polymer, through conducting, after the radical polymerization process, a hydrolysis reaction and a polycondensation reaction of a hydrolyzable group X in the formula (3): R6mSiX4-m ...(3) (In the formula (3), X denotes a hydrolyzable group, m denotes an integer of 1 to 3, R6 each is independently an organic group having 1 to 20 carbon atoms, and at least one R6 is a radical-polymerizable group.).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to external additive particles, a method for producing the same, and toner.

Background Art

[0002] In recent years, image forming apparatuses using electrophotography have been required to be faster and to have higher image quality. Along with these requirements, in order to have stress resistance that can withstand rubbing in the developing device for a long time and to obtain high image quality even in high-speed printing, toners having excellent fluidity and developability have been studied.

[0003] Patent Document 1 discloses a method for producing organic-inorganic composite particles having an organic polymer skeleton and a polysiloxane skeleton as an additive for toner. It is disclosed that by incorporating the additive for toner into the toner, the transfer characteristics and the like of the toner are improved.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] As a result of the inventors' examination of the toner externally added with the particles produced by the method described in Patent Document 1, it was recognized that further improvement in the fluidity of the toner is necessary.

[0006] One aspect of the present invention is directed to providing external additive particles and a method for producing the same that can provide a toner having excellent fluidity and whose fluidity hardly changes even when continuous image output is performed.

[0007] Another aspect of the present invention is directed to providing a toner that can have excellent fluidity and is less likely to change in fluidity even when continuous image output is performed.

Means for Solving the Problems

[0008] According to one aspect of the present invention, there is provided a method for producing external additive particles containing a polymer, wherein the production method a radical polymerization step of performing a radical polymerization reaction of a monomer raw material containing a compound represented by the following formula (3) using a radical polymerization initiator having a carboxy group under the condition of 6.0 ≦ pH ≦ 8.0, and a condensation step of performing a hydrolysis reaction and a polycondensation reaction of the hydrolyzable group X in the following formula (3) after the radical polymerization step to obtain particles containing a polymer. A method for producing external additive particles including the above is provided.

[0009] R 6 m SiX 4-m ··· (3) (In formula (3), X is a hydrolyzable group, m is an integer of 1 to 3, and each R 6 is independently an organic group having 1 to 20 carbon atoms, and at least one of R 6 is a radically polymerizable group.) Also, according to another aspect of the present invention, there is provided a method for producing external additive particles containing a polymer, wherein the production method a radical polymerization step of performing a radical polymerization reaction of a monomer raw material containing at least one of a radically polymerizable carboxylic acid and a radically polymerizable carboxylate, and a compound represented by the following formula (3) under the condition of 6.0 ≦ pH ≦ 8.0, a condensation step of performing a hydrolysis reaction and a polycondensation reaction of the hydrolyzable group X in the following formula (3) after the radical polymerization step to obtain particles containing a polymer. A method for producing external additive particles including the above is provided.

[0010] R 6 m SiX4-m ··· (3) (In formula (3), X is a hydrolyzable group, m is an integer from 1 to 3, and R 6 are each independently an organic group having 1 to 20 carbon atoms, and at least one of R 6 is a radically polymerizable group.) [Advantages of the Invention]

[0011] According to one aspect of the present invention, it is possible to obtain external additive particles that can provide a toner having excellent fluidity and that can maintain excellent fluidity retention even when continuous image output is performed. Further, according to another aspect of the present invention, it is possible to obtain a toner that can maintain excellent fluidity retention even when continuous image output is performed. [Embodiments for Carrying Out the Invention]

[0012] The description of "XX or more and XX or less" or "XX to XX" representing a numerical range means a numerical range including the lower limit and the upper limit which are endpoints, unless otherwise specified. When numerical ranges are described stepwise, the upper and lower limits of each numerical range can be arbitrarily combined.

[0013] [Background of the Invention] The inventors of the present invention consider the reasons for further improving the fluidity of the toner externally added with the particles produced by the production method according to Patent Document 1 as follows.

[0014] It has been discovered that the toner externally added with the particles produced by the production method according to Patent Document 1 may not have sufficient fluidity. In this production method, since hydrolysis and polycondensation of the hydrolyzable group bonded to silicon are performed and then polymerization of the vinyl group is performed, it is considered that particles having a polysiloxane backbone are formed. Since the main backbone of the particles is an inorganic backbone, the adhesion force to the toner particles may not be sufficient, and the inventors consider that the fact that the particles are likely to separate from the surface of the toner particles is one of the reasons for the decrease in the fluidity of the toner.

[0015] Therefore, the inventors of the present invention studied particles whose main skeleton is a molecular chain of a vinyl polymer, which are obtained by a production method in which hydrolysis and polycondensation are carried out after vinyl polymerization. As a result, it was found that the particles are less likely to separate from the toner particles, and a certain improvement was observed in the fluidity of the toner. However, there was still room for further improvement in the change over time of the fluidity of the toner, that is, the fluidity maintenance property of the toner, when continuous image output was performed.

[0016] As a result of intensive studies by the inventors of the present invention based on the above considerations, it was found that a toner externally added with external additive particles produced by a production method having the above-described constituent requirements can have excellent fluidity and is likely to obtain a toner having excellent fluidity maintenance property. The presumed mechanism of the effect expression and each constituent requirement will be described in detail below.

[0017] <Presumed mechanism for the expression of the effects of the present invention> After radical polymerization using a monomer raw material containing the compound represented by formula (3), hydrolysis and polycondensation are carried out to obtain a polymer having a molecular chain of a vinyl-based polymer as the main skeleton, and the polymer contains a structure in which the molecular chains are bonded via siloxane bonds.

[0018] Since the main skeleton of the polymer is a molecular chain of a vinyl-based polymer, the adhesion force to the toner particles is likely to increase. In addition, since the molecular chains of the vinyl-based polymer have a structure bonded via siloxane bonds, it is considered that the mechanical strength of the external additive particles is likely to increase and plastic deformation is less likely to occur.

[0019] As a result, it is considered that the external additive particles containing the above polymer are less likely to separate from the toner particles and are less likely to undergo plastic deformation, so that a toner having excellent fluidity is easily obtained.

[0020] Further, in the method for producing external additive particles according to the present invention, it is considered that a carboxy group is contained in the surface region of the produced external additive particles by at least one of the following (i) and (ii). (i) In the radical polymerization step, a radical polymerization initiator having a carboxy group is used. (ii) As a monomer raw material, at least one of a radically polymerizable carboxylic acid and a radically polymerizable carboxylate is used.

[0021] The inventors presume that when a carboxy group is contained in the surface region of the external additive particles, it becomes easier to strongly interact with the portions capable of electrostatic interaction present on the surface of the toner particles, and the external additive particles are less likely to separate from the surface of the toner particles. As a result, even when continuous image output is performed, it becomes easier to obtain a toner having excellent flow maintenance properties.

[0022] <Method for producing external additive particles> The method for producing external additive particles according to the present invention performs a radical polymerization reaction using a compound represented by the following formula (3) containing both a radically polymerizable group and a hydrolyzable group that forms a siloxane bond by hydrolysis and polycondensation, and then performs a hydrolysis reaction and a polycondensation reaction.

[0023] R 6 m SiX 4-m ··· (3) (In formula (3), X is a hydrolyzable group, m is an integer of 1 to 3, and R 6 are each independently an organic group having 1 to 20 carbon atoms, and at least one of R 6 is a radically polymerizable group.) By performing the radical polymerization reaction under neutral conditions before performing hydrolysis and polycondensation, a polymer having a molecular chain of a vinyl-based polymer as a main skeleton can be obtained. Further, after the molecular chain of the vinyl-based polymer is formed by the radical polymerization reaction, by performing hydrolysis and polycondensation, a polymer having a structure in which the molecular chains of the vinyl-based polymer are bonded via siloxane bonds can be obtained. Further, by performing the hydrolysis reaction and the polycondensation reaction later, it is considered that a carboxy group that easily interacts with water molecules is likely to be contained in the surface region of the external additive particles.

[0024] Examples of the hydrolyzable group include, for example, a functional group that is converted to a hydroxy group after hydrolysis of the above compound, or a hydroxy group.

[0025] In addition, the radically polymerizable group means a substituent having a radically reactive double bond in the structure. R in the above formula (3) 6 is more preferably an organic group having 1 to 15 carbon atoms, and still more preferably, R 6 is an organic group having 1 to 10 carbon atoms.

[0026] Here, as the radical polymerization initiator, it is preferable to use a radical polymerization initiator having a carboxy group because a carboxy group can be contained in the surface region of the external additive particles. The radical polymerization initiator is preferably an azo compound.

[0027] Preferable examples of the radical polymerization initiator having a carboxy group include a compound represented by the following formula (2). Examples of the compound used as the radical polymerization initiator represented by the following formula (2) include 2,2′-azobis[N-(2-carboxyethyl)-2-methylpropionamidine].

[0028]

Chemical formula

[0029] (In formula (2), R 5 is an alkylene group having 1 to 12 carbon atoms.) In addition to using the above radical polymerization initiator, examples of the method for incorporating a carboxy group into the surface region of the external additive particles include incorporating at least one of a radically polymerizable carboxylic acid and a radically polymerizable carboxylate into the monomer raw material.

[0030] Examples of the radical polymerizable carboxylate include the following: sodium 4-vinylbenzoate, potassium 4-vinylbenzoate, lithium 4-vinylbenzoate, magnesium 4-vinylbenzoate, calcium 4-vinylbenzoate, ammonium 4-vinylbenzoate, sodium (meth)acrylate, potassium (meth)acrylate, lithium (meth)acrylate, magnesium (meth)acrylate, calcium (meth)acrylate, ammonium (meth)acrylate, and the like. These radical polymerizable carboxylates may be used alone or in combination of two or more.

[0031] Examples of the radical polymerizable carboxylic acid include 4-vinylbenzoic acid, (meth)acrylic acid, and the like. These may be used alone or in combination of two or more.

[0032] From the viewpoint of maintaining the fluidity of the toner, the total mass of the above radical polymerizable carboxylic acid and radical polymerizable carboxylate is preferably 0.4 to 7.0% by mass, more preferably 0.6 to 5.0% by mass, and still more preferably 0.6 to 2.0% by mass with respect to the total mass of the monomer raw materials.

[0033] <Radical polymerization reaction> As the method of the radical polymerization reaction, an emulsion polymerization method is preferably used. The emulsion polymerization method is a polymerization method in which a medium such as water, a monomer hardly soluble in the medium, and an emulsifier (surfactant) or an ionic comonomer are mixed, and a polymerization initiator soluble in the medium is added thereto. Further, the above emulsion polymerization method is preferably a soap-free emulsion polymerization method in which polymerization is carried out without using a surfactant. The present inventors consider that by using the soap-free emulsion polymerization method, the surfactant does not remain on the surface of the external additive particles, and it is easy to control the affinity between the toner particles and the external additive particles.

[0034] Examples of the hydrolyzable group in the above formula (3) include monovalent groups selected from a hydroxy group, a fluoro group, a chloro group, a bromo group, an iodo group, an alkoxy group, and an acyloxy group. Preferred are a methoxy group, an ethoxy group, a propoxy group, and an acetoxy group, and more preferred are a methoxy group and an ethoxy group. Since these hydrolyzable groups are easily hydrolyzed by water and the subsequent polycondensation reaction easily occurs, it is considered that the polysiloxane skeleton is easily contained in the external additive particles.

[0035] From the viewpoints of the fluidity and fluidity maintenance property of the toner, the compound represented by the above formula (3) is preferably 50 to 80% by mass based on the total mass of the monomer raw materials. More preferably, it is 60 to 75% by mass.

[0036] Specific examples of the compound represented by the above formula (3), that is, the monomer containing both a radically polymerizable group and a hydrolyzable group, include, for example, the following.

[0037] Organotrialkoxysilane compounds such as γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-acryloxypropyltrimethoxysilane, γ-acryloxypropyltriethoxysilane, γ-methacryloxypropyltriacetoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, 1-hexenyltrimethoxysilane, 1-octenyltrimethoxysilane, etc., organotriacetoxysilane, bis(γ-acryloxypropyl)dimethoxysilane, bis(γ-methacryloxypropyl)dimethoxysilane, γ-methacryloxypropylethyldimethoxysilane, γ-methacryloxypropylethyldiethoxysilane, γ-acryloxypropylethyldimethoxysilane, γ-acryloxypropylethyldiethoxysilane and other diorganodialkoxysilane compounds, 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-acryloxypropyldiethyl ethoxysilane, γ-methacryloxypropyldiethylmethoxysilane, γ-methacryloxypropyldiethyl ethoxysilane and other triorganoalkoxysilane compounds, etc.

[0038] Among the above monomers, more preferably, they are γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-acryloxypropyltrimethoxysilane, γ-acryloxypropyltriethoxysilane, γ-methacryloxypropyltriacetoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane.

[0039] The compound represented by the above formula (3) is preferably the compound represented by the following formula (1).

[0040] [Chemical formula]

[0041] (In formula (1), R 1 is an alkylene group having 1 to 10 carbon atoms, and R 2 , R 3 , and R 4 are each independently either hydrogen, a methyl group, or an ethyl group, and R' is hydrogen or a methyl group.) [Radical polymerization initiator] In addition to the radical polymerization initiator having a carboxy group described above, examples of radical polymerization initiators that can be used include at least one compound selected from persulfates, azo compounds, and peroxides.

[0042] Examples of persulfates include potassium persulfate, sodium persulfate, ammonium persulfate, etc. These may be used alone or in combination of two or more.

[0043] The amount of the radical polymerization initiator in the radical polymerization step is not particularly limited, but is preferably 0.1 to 10.0% by mass, more preferably 0.3 to 5.0% by mass, based on the total mass of the raw material monomers. When the radical polymerization initiator is within the above range, radical polymerization can proceed sufficiently, and it is preferable because the amount of heat generated in the reaction system is less likely to become excessive.

[0044] [Reaction conditions for radical polymerization] The temperature for radical polymerization can be appropriately selected depending on the type and amount of the radical polymerization initiator used, and is preferably in the range of 30 to 100 °C, more preferably in the range of 50 to 80 °C.

[0045] The radical polymerization step is a step of performing radical polymerization under the condition of 6.0 ≦ pH ≦ 8.0. More preferably, it is 6.5 ≦ pH ≦ 7.5. When the pH of the reaction system is within the above range, it is considered that hydrolysis and polycondensation reactions of the hydrolyzable groups are less likely to occur during the progress of the radical polymerization reaction. After radical polymerization, by performing hydrolysis and polycondensation reactions, it becomes easier to control the ratio of the polysiloxane skeleton in the externally added agent particles, and it is considered that a carboxy group having a higher polarity is more likely to be contained in the surface region of the externally added agent particles. Therefore, the radical polymerization reaction is preferably carried out in a buffer solution. The buffer solution is not particularly limited, and any buffer solution showing a pH near neutrality such as a phosphate buffer solution or a MES buffer solution may be used.

[0046] Also, when performing radical polymerization, not only a monomer containing both a radically polymerizable group and a hydrolyzable group, but also other monomers having a radically polymerizable group may be used.

[0047] Examples of the other monomers include unsaturated carboxylic acids such as acrylic acid and methacrylic acid, unsaturated carboxylic acid esters such as acrylic acid esters, methacrylic acid esters, crotonic acid esters, 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 compounds such as vinyl halide compounds. Further, monomers such as divinylbenzene, trimethylolpropane trimethacrylate, and ethylene glycol dimethacrylate containing two or more radically polymerizable groups may be used. These may be used alone or in combination of two or more.

[0048] <Hydrolysis reaction and polycondensation reaction> The method of the hydrolysis reaction and polycondensation reaction described above is not particularly limited, but it is preferable to add a catalyst such as an acid or a base to an emulsion containing particles obtained by radical polymerization, and then perform hydrolysis and polycondensation as it is to obtain particles containing a polymer. That is, it is preferable that the condensation step is a step of performing a hydrolysis reaction and a polycondensation reaction of the hydrolyzable group X in the formula (3) after the radical polymerization step to obtain particles of a condensate. Further, after isolating the particles obtained by radical polymerization from the emulsion by performing operations such as filtration, centrifugation, and concentration under reduced pressure, a catalyst may be added for hydrolysis and polycondensation.

[0049] In carrying out the hydrolysis and polycondensation reactions after particle formation by radical polymerization reaction, catalysts such as acetic acid, hydrochloric acid, ammonia, urea, alkanolamine, tetraalkylammonium hydroxide, alkali metal hydroxide, alkaline earth metal hydroxide, etc. may be used.

[0050] More preferable catalysts from the viewpoint of further promoting polycondensation include organotitanium compounds such as titanium tetraisopropoxide, titanium tetrabutoxide, diisopropoxy-bis(acetylacetonate)titanate, organoaluminum compounds such as aluminum triisopropoxide, aluminum trisec-butoxide, aluminum trisacetylacetonate, aluminum isopropoxide-bisacetylacetonate, organozirconium compounds such as zirconium tetrabutoxide, tetrakis(acetylacetonate)zirconium, organotin compounds such as dibutyltin diacetate, dibutyltin diethylhexanoate, 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 organotin compounds and acidic phosphate esters is preferable.

[0051] In addition, the solvent used in the production of the external additive particles may contain water or an organic solvent other than a catalyst. Specific examples of the organic solvent include alcohols such as methanol, ethanol, isopropanol, n-butanol, isobutanol, sec-butanol, t-butanol, pentanol, ethylene glycol, propylene glycol, 1,4-butanediol, etc., ketones such as acetone, methyl ethyl ketone, etc., esters such as ethyl acetate, etc., (cyclo)paraffins such as isooctane, cyclohexane, etc., ethers such as dioxane, diethyl ether, etc., aromatic hydrocarbons such as benzene, toluene, etc. Two or more of them may be mixed and used.

[0052] The hydrolysis reaction and the polycondensation reaction can be carried out, for example, by appropriately adding a catalyst to an emulsion prepared by a radical polymerization reaction and stirring at 0 to 100 °C, preferably in the range of 0 to 70 °C for 3 to 24 hours.

[0053] <Surface treatment with an amine compound> From the viewpoint of the density stability of the output image, it is preferable to perform surface treatment of the particles containing the above polymer with an amine compound. By performing this surface treatment, it has been found that the image density is less likely to vary in image output in a low-humidity environment. The reason for this is not clear, but the present inventors speculate as follows.

[0054] In the process of charge acquisition of the toner by triboelectrification, negative charges tend to accumulate in the toner due to the influence of negatively charged functional groups present on the surface of the external additive particles or the toner particles, such as carboxy groups. By performing surface treatment with an amine compound, the amine moiety derived from the amine compound is likely to receive hydrogen ions and thus have a positive charge, and it is considered that excessive accumulation of negative charges in the whole toner is less likely to occur. As a result, it is considered that even in a low-humidity environment where the toner is likely to be excessively charged, excessive charging of the toner is less likely to occur, and a toner with less variation in image density can be easily obtained.

[0055] The amine compound used in the surface treatment and the particles containing the polymer may or may not be chemically bonded.

[0056] Examples of the amine compound include aminosilanes such as 3-aminopropyltrimethoxysilane, 3-(2-aminoethylamino)propyltrimethoxysilane, 3-(2-aminoethylamino)propyldimethoxydimethylsilane, amino group-containing polymers such as polyallylamine, and polyethyleneimine.

[0057] The content of the amine moiety contained in the surface region of the external additive particles by the surface treatment using the amine compound can be confirmed by performing X-ray photoelectron spectroscopy on the surface of the external additive particles. Further, when X-ray photoelectron spectroscopy is performed on the surface of the external additive particles subjected to the surface treatment, the ratio of the number of nitrogen atoms to the total number of carbon atoms, nitrogen atoms, oxygen atoms, and silicon atoms is preferably 1.0% or more and 2.5% or less. It has been found that when the ratio of the number of nitrogen atoms is within the above range, the image density is less likely to vary in a low-humidity environment.

[0058] Also, from the viewpoint of the chargeability of the toner, it is preferable to perform surface treatment of the external additive particles using other surface treatment agents in order to treat the hydroxyl groups remaining on the surface of the external additive particles and adjust the negative charge amount. Examples of the other surface treatment agents include silicon compounds such as organoalkoxysilane and hexamethyldisilazane, titanium compounds such as tetrabutyl titanate, or hydrolysis / condensation products thereof.

[0059] The surface treatment using the other surface treatment agent may be performed simultaneously with the surface treatment using the above amine compound, or may be performed after the surface treatment using the above amine compound.

[0060] As a method for performing the above surface treatment, there is no particular limitation as long as the surface of the particles can be coated with the above surface treatment agent. For example, the particles can be put into an appropriate container, and then the surface treatment agent is added. After that, while stirring, the mixture is mixed and contacted at a temperature of about room temperature (25°C ± 5°C) to 100°C for 3 to 24 hours. In this case, the surface treatment agent is dissolved in a solvent such as methanol, and this is gradually dropped while mixing and contacting to perform the surface treatment more uniformly. The amount of the surface treatment agent present on the surface of the particles can be adjusted by appropriately selecting the type of the surface treatment agent, the time of the surface treatment, the particle size of the externally added agent particles, etc. The object to be treated surface-treated in this way can be washed with, for example, alcohol as necessary to obtain externally added agent particles from which unnecessary substances have been removed.

[0061] <Post-treatment> The particles obtained by performing radical polymerization, hydrolysis / polycondensation, and surface treatment as described above are isolated from the slurry using methods such as filtration, centrifugation, vacuum concentration, spray drying, and instantaneous vacuum drying, and then it is preferable to perform a drying treatment at 30 to 100°C. More preferably, the drying treatment is performed at 30 to 80°C, and even more preferably at 50 to 70°C. By performing this drying treatment, it is easy to obtain externally added agent particles having appropriate charging characteristics and appropriate mechanical strength.

[0062] <Physical properties of externally added agent particles> <Ratio of the number of silicon atoms to the total number of carbon atoms, oxygen atoms, and silicon atoms> It is preferable that the ratio of the number of silicon atoms to the total number of carbon atoms, oxygen atoms, and silicon atoms in the externally added agent particles is 4.0% or more and 25.0% or less.

[0063] The inventors believe that the total number of carbon atoms, oxygen atoms, and silicon atoms is an indicator of how much polymer having a structure in which the molecular chains of the above vinyl polymer are bonded via siloxane bonds exists. Further, the inventors believe that the ratio of the number of silicon atoms to the total number of the above atoms is an indicator of how much siloxane bonds exist.

[0064] When the above ratio is 4.0% or more, if siloxane bonds are sufficiently formed in the polymer, it is considered that plastic deformation of the external additive particles is less likely to occur, so a toner having excellent fluidity is easily obtained. Also, when the above ratio is 25.0% or less, it is considered that the molecular chains of the vinyl polymer as the main skeleton are sufficiently contained in the polymer, and the external additive particles are less likely to separate from the toner particles, so a toner having excellent flow retention is easily obtained. Therefore, it is 25.0% or less, preferably 20.0% or less, more preferably 15.0% or less, and even more preferably 10.0% or less. That is, it is more preferably 4.0% or more and 10.0% or less.

[0065] Also, since a toner having excellent flow retention is easily obtained, the ratio of the number of carbon atoms in the external additive particles is preferably 6.5 or more with respect to the number of silicon atoms in the external additive particles. More preferably, it is 7.5 or more, and even more preferably 13.5 or more. The upper limit is not particularly limited, but from the viewpoint of the fluidity of the toner, it is preferably 20.0 or less. More preferably, it is 17.0 or less.

[0066] The above ratio of the number of atoms can be controlled by adjusting the type and amount of monomer units containing silicon atoms, and the type and amount of monomer units not containing silicon atoms, etc. when manufacturing the polymer constituting the external additive particles.

[0067] <D50 of external additive particles> As an external additive particle, in order to have an appropriate volume average particle diameter, when the 50% particle diameter based on the volume distribution of the external additive particle is defined as D50, it is preferable that the D50 is 50 nm or more and 200 nm or less.

[0068] <Toner> The external additive particles according to the present invention are preferably contained on the surface of the toner particles. That is, as one aspect of the present invention, a toner containing toner particles and an external additive on the surface of the toner particles, wherein the external additive is an external additive particle produced by the production method according to the present invention is preferable.

[0069] Further, the toner particles preferably contain a binder resin. Examples of the binder resin include polyester resins, vinyl resins, epoxy resins, and polyurethane resins.

[0070] From the viewpoint of storage stability, the glass transition point (Tg) of the binder resin is preferably 45 to 70°C.

[0071] <Method for producing toner particles> The method for producing 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, and a dissolution suspension method can be used.

[0072] The pulverization method will be described. In the pulverization method, first, a binder resin, a colorant, a wax, a charge control agent, etc. constituting the toner particles are sufficiently mixed by a mixer such as a Henschel mixer or a ball mill. Next, the obtained mixture is melt-kneaded using a heat kneader such as a twin-screw kneading extruder, a heating roll, a kneader, or an extruder, and after cooling and solidifying, pulverization and classification are performed. Thereby, the toner particles according to the present invention are obtained.

[0073] Examples of kneaders 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 Manufacturing); Needex (manufactured by Mitsui Mining); MS type pressure kneader, kneader luder (manufactured by Nippon Spindle); Banbury mixer (manufactured by Kobe Steel).

[0074] Examples of crushers include the following: Counter jet mill, micron jet, inomizer (manufactured by Hosokawa Micron); IDS type mill, PJM jet crusher (manufactured by Nippon Pneumatic Mfg. Co., Ltd.); Cross jet mill (manufactured by Kurimoto Iron Works); Urmax (manufactured by Nippon Catalytic Chemical Industries, Ltd.); SK jet or mill (manufactured by Seishin Enterprise Co., Ltd.); Cryptron (manufactured by Kawasaki Heavy Industries, Ltd.); Turbo mill (manufactured by Turbo E Co., Ltd.); Super rotor (manufactured by Nisshin Engineering Co., Ltd.).

[0075] Examples of classifiers include the following: Crassier, micron classifier, speedy classifier (manufactured by Seishin Enterprise Co., Ltd.); Turbo classifier (manufactured by Nisshin Engineering Co., Ltd.); Micron separator, turbo prex (ATP), TSP separator (manufactured by Hosokawa Micron); Elbow jet (manufactured by Nippon Steel Mining Co., Ltd.), dispersion separator (manufactured by Nippon Pneumatic Mfg. Co., Ltd.); YM micro cut (manufactured by Yaskawa Shoji Co., Ltd.).

[0076] The suspension polymerization method will be described. In the suspension polymerization method, first, a polymerizable monomer capable of forming a binder resin and various additives as necessary are mixed, and using a dispersing machine, a polymerizable monomer composition in which the material is dissolved or dispersed is prepared. Examples of the various additives include a colorant, wax, charge control agent, polymerization initiator, chain transfer agent, and the like. Examples of the dispersing machine include a homogenizer, ball mill, colloid mill, or ultrasonic disperser. Next, the polymerizable monomer composition is put into an aqueous medium containing hardly water-soluble inorganic fine particles, and droplets of the polymerizable monomer composition are prepared using a high-speed dispersing machine such as a high-speed stirrer or ultrasonic disperser (granulation step). Then, the polymerizable monomer in the droplets is polymerized to obtain toner particles (polymerization step). The polymerization initiator may be mixed when preparing the polymerizable monomer composition, or may be mixed into the polymerizable monomer composition immediately before forming droplets in the aqueous medium. Further, during or after the granulation of the droplets, that is, immediately before starting the polymerization reaction, it can also be added as needed in a state dissolved in a polymerizable monomer or other solvent. After obtaining a binder resin by polymerizing the polymerizable monomer, a desolvent treatment may be performed as necessary to obtain a dispersion of toner particles.

[0077] <Method for externally adding external additive particles to toner particles> The toner according to the present invention can be obtained by mixing toner particles and external additive particles using a mixer such as a Henschel mixer.

[0078] Examples of the mixer 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 Corporation); Spiral Pin Mixer (manufactured by Pacific Machine Industry Co., Ltd.); Lodige mixer (manufactured by Matsubo Co., Ltd.).

[0079] Further, it is preferable that the toner particles contain the above external additive particles on their surfaces and also contain other external additives. Examples of the other external additives include the following.

[0080] Fluorine-based resin powders such as vinylidene fluoride fine powder and polytetrafluoroethylene fine powder; fine powder silica such as wet-process silica and dry-process silica, fine powder titanium oxide, fine powder alumina, and treated silica obtained by surface-treating them with silane compounds, titanium coupling agents, and silicone oil; oxides such as zinc oxide and tin oxide; complex oxides such as strontium titanate, barium titanate, calcium titanate, strontium zirconate, and calcium zirconate; carbonate compounds such as calcium carbonate and magnesium carbonate, etc.

[0081] <Various Additives for Toner> The toner may contain one or more additives selected from colorants, waxes, magnetic materials, charge control agents, etc., if necessary. Specific descriptions will be given for various additives used in the toner.

[0082] <Magnetic Material> Magnetic particles may be contained in the toner and used as a magnetic toner. In this case, the magnetic particles may also serve as a colorant.

[0083] Examples of the magnetic particles contained in the magnetic toner include the following.

[0084] Iron oxides such as magnetite, hematite, and ferrite, metals such as iron, cobalt, and nickel, or 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.

[0085] It is preferable that the average particle diameter of the above magnetic particles is 2 μm or less. More preferably, it is 0.05 μm or more and 0.5 μm or less. Also, as the content ratio of the above magnetic particles, it is preferably 20 parts by mass or more and 200 parts by mass or less with respect to 100 parts by mass of the binder resin, and more preferably 40 parts by mass or more and 150 parts by mass or less with respect to 100 parts by mass of the binder resin.

[0086] <Colorant> Examples of the colorant include the following.

[0087] As the black colorant, for example, carbon black, grafted carbon, or those toned to black using the yellow / magenta / cyan colorants shown below.

[0088] As the yellow colorant, compounds typified by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds.

[0089] As the magenta colorant, condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, perylene compounds, etc. are mentioned. As the cyan colorant, copper phthalocyanine compounds and their derivatives, anthraquinone compounds, basic dye lake compounds, etc.

[0090] The colorant can be used alone, mixed, or even in a solid solution state. Also, the colorant is selected from the viewpoints of hue angle, chroma, lightness, weather resistance, OHP transparency, and dispersibility in the toner.

[0091] The content ratio of the colorant is preferably 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin.

[0092] <Wax> Examples of the wax include the following.

[0093] Aliphatic hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, polyolefin copolymers, polyolefin waxes, microcrystalline waxes, paraffin waxes, Fischer-Tropsch waxes, oxides of aliphatic hydrocarbon waxes such as oxidized polyethylene wax, block copolymers of aliphatic hydrocarbon waxes, and their oxides.

[0094] Ester waxes mainly composed of fatty acid esters such as carnauba wax; those in which part or all of the fatty acid esters such as deacidified carnauba wax are deoxidized.

[0095] <Charge control agent> The charge control agent is not particularly limited, but is preferably an organometallic complex or a chelate compound. For example, monoazo metal complexes; acetylacetone metal complexes; metal complexes or metal salts of aromatic hydroxycarboxylic acids or aromatic dicarboxylic acids can be mentioned.

[0096] Specific examples that can be used include Spilon Black TRH, T-77, T-95 (Hodogaya Chemical Co., Ltd.), BONTRON (registered trademark) S-34, S-44, S-54, E-84, E-88, E-89 (Orient Chemical Co., Ltd.). In addition, a charge control resin can also be used in combination with the above-mentioned charge control agent.

[0097] <Developer> The toner can be used as a one-component developer, but in order to further improve dot reproducibility and to supply a stable image over a long period of time, it may be mixed with a magnetic carrier and used as a two-component developer.

[0098] As the magnetic carrier, for example, metals such as iron with an oxidized surface, iron without an oxidized surface, nickel, cobalt, manganese, chromium, rare earths, etc., and their alloys or oxides are preferably used.

[0099] In addition, those in which the surface of the magnetic carrier contains or is coated with a styrene-based resin, an acrylic-based resin, a silicone-based resin, a fluorine-based resin, or a polyester are preferred.

[0100] <Various measurement methods, etc.> Hereinafter, various measurement methods, etc. will be described.

[0101] <Method for Measuring Ratio of Number of Silicon Atoms to Total Number of Carbon, Oxygen, and Silicon Atoms Present in Additive Particles and Abundance Ratio of Carbon Atoms to Silicon Atoms> ·Carbon atoms and oxygen atoms The concentrations (atomic %) of carbon atoms and oxygen atoms present in the additive particles are calculated using elemental analysis by combustion. The apparatus for elemental analysis is shown below. Apparatus used: PerkinElmer 2400II fully automatic elemental analyzer ·Silicon atoms The concentration (atomic %) of silicon atoms present in the additive particles is measured using elemental analysis by inductively coupled plasma atomic emission spectrometry (ICP-AES) by alkali fusion. The apparatus for ICP-AES is shown below. Apparatus used: Shimadzu ICPS-8100 By converting the obtained composition ratio to mol%, using the converted value, the ratio of the number of silicon atoms to the total number of carbon, oxygen, and silicon atoms in the additive particles is calculated. Similarly, the ratio of the number of carbon atoms to the number of silicon atoms in the additive particles is calculated.

[0102] <Method for Measuring Ratio of Number of Nitrogen Atoms to Total Number of Carbon, Nitrogen, Oxygen, and Silicon Atoms in Surface Region of Additive Particles> The ratio of the number of nitrogen atoms present in the surface region of the additive particles is measured by X-ray photoelectron spectroscopy. The apparatus and measurement conditions are shown below. ·Apparatus used: ULVAC-PHI PHI Quantera SXM ·X-ray photoelectron spectrometer measurement conditions: X-ray source Al Kα (1486.6 eV) 200 μmφ PassEnergy: 140 eV Charge neutralization: Combined use of electron neutralization gun and Ar ion neutralization gun Number of sweeps: C 20 times, N 100 times, O 20 times, Si 20 times From the peak intensities of each measured element, using the relative sensitivity factors provided by ULVAC-PHI, the atomic concentrations (all in atomic %) of carbon atoms, nitrogen atoms, oxygen atoms, and silicon atoms present in the surface region of the additive particles were calculated. From these results, the ratio of the number of nitrogen atoms to the total number of carbon atoms, nitrogen atoms, oxygen atoms, and silicon atoms on the surface of the additive particles was calculated.

[0103] <Method for Measuring the 50% Particle Size (D50) Based on the Volume Distribution of the Fine Particle Sample> For the measurement of the 50% particle size (D50) based on the volume distribution of the fine particle sample, a dynamic light scattering particle size distribution analyzer NanoTrack UPA-EX150 (manufactured by Nikkiso Co., Ltd.) is used. Specifically, the range is set to 0.001 μm to 10 μm, and the measurement is performed according to the following procedure.

[0104] To prevent aggregation of the measurement sample, a dispersion in which the measurement sample is dispersed is introduced into an aqueous solution containing Family Fresh (manufactured by Kao Corporation) and stirred. After stirring, the measurement sample is injected into the above device, and two measurements are performed to obtain the average value.

[0105] As the measurement conditions, the measurement time is set to 30 seconds, the refractive index of the sample particles is set to 1.49, the dispersion medium is water, and the refractive index of the dispersion medium is set to 1.33.

[0106] The volume 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 becomes 50% is defined as the 50% particle size (D50) based on the volume distribution of each fine particle.

Examples

[0107] Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited to these examples. Unless otherwise specified, "parts" and "%" mean "parts by mass" and "mass %", respectively. Also, each measurement result in the examples is the result measured by the measurement method described above.

[0108] <Production Example of Additive 1> The following materials were charged into a glass reactor equipped with a thermometer, a reflux condenser, a nitrogen gas inlet tube, and a stirrer. · Phosphate buffer (pH = 7.0, prepared using sodium dihydrogen phosphate dihydrate (manufactured by Kishida Chemical Co., Ltd.) and disodium hydrogen phosphate dodecahydrate (manufactured by Kishida Chemical Co., Ltd.)) 200 parts · 0.1 mol / l aqueous sodium hydroxide solution (manufactured by Kishida Chemical Co., Ltd.) 1.2 parts · Emulsifier: Sodium 4-vinylbenzoate (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.18 part · Monomer having a radical polymerizable group and a hydrolyzable group: 3-(Trimethoxysilyl)propyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) 11.0 parts · Non-hydrolyzable monomer: Styrene (manufactured by Tokyo Chemical Industry Co., Ltd.) 4.7 parts Subsequently, while introducing nitrogen gas, the mixture was heated to 65 - 70 °C and stirred for 30 minutes. Then, as an initiator, 1.5 parts of 2,2′-azobis[N-(2-carboxyethyl)-2-methylpropionamidine] (VA-057, manufactured by Fuji Film Wako Pure Chemical Corporation) was added, and stirring was continued for 6 hours to obtain a particle emulsion. To the obtained particle emulsion, as an ammonia treatment, 28 mass% aqueous ammonia (manufactured by Kishida Chemical Co., Ltd.) was added to adjust the pH of the emulsion to 11.0, and then the mixture was stirred at 50 °C for 3 hours to perform hydrolysis and polycondensation of the hydrolyzable groups contained in the particles. Thereafter, ultrafiltration was performed to remove excess solutes, and concentration / filtration was repeated 5 times in total. Then, 0.13 part of 3-aminopropyltrimethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.) as a nitrogen atom source and 27.0 parts of 1,1,1,3,3,3-hexamethyldisilazane (manufactured by Kishida Chemical Co., Ltd.) as a hydrophobizing agent were added, and the mixture was stirred at 50 °C for 24 hours. Then, it was dried by spray drying to obtain Exterior Additive 1 having a volume distribution-based 50% particle size (hereinafter, also referred to as D50) of 130 nm. The physical properties of Exterior Additive 1 are shown in Table 2.

[0109] <Manufacturing Examples of Exterior Additives 2 - 19> Except that the materials used were changed as shown in Table 1, the same operations as in the manufacturing example of Exterior Additive 1 were performed to obtain Exterior Additives 2 - 19. The physical properties of Exterior Additives 2 - 19 are shown in Table 2.

[0110] <Production Example of Exterior Additive 20> At room temperature, a solution prepared by mixing the following materials was added to a solution obtained by mixing 46.7 parts of 28% by mass aqueous ammonia and 2114 parts of deionized water, and the mixture was stirred for 2 hours to perform hydrolysis and polycondensation of 3-(trimethoxysilyl)propyl methacrylate. · 3-(Trimethoxysilyl)propyl methacrylate: 22.1 parts · Methanol (manufactured by Kishida Chemical Co., Ltd.): 73.7 parts · Initiator: 2,2'-azobis(2,4-dimethylvaleronitrile) (V-65, manufactured by Fujifilm Wako Pure Chemical Corporation): 0.12 part Next, while purging with nitrogen gas, the mixture was heated to 70 - 75 °C and stirred for 2 hours to perform radical polymerization. Then, ultrafiltration was performed to remove excess solute, and concentration / filtration was repeated a total of 5 times. Thereafter, 0.22 part of 3-aminopropyltrimethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.) and 27.0 parts of 1,1,1,3,3,3-hexamethyldisilazane (manufactured by Kishida Chemical Co., Ltd.) as a hydrophobizing agent were added, and the mixture was stirred at 50 °C for 24 hours. Then, it was dried by spray drying to obtain Exterior Additive 20. The physical properties of Exterior Additive 20 are shown in Table 2.

[0111] <Production Example of Exterior Additive 21> The following materials were charged into a glass reactor equipped with a thermometer, a reflux condenser, a nitrogen gas inlet tube, and a stirrer. · Deionized water: 200 parts · 0.1 mol / l aqueous sodium hydroxide solution (manufactured by Kishida Chemical Co., Ltd.): 1.2 parts · Emulsifier: Sodium 4-vinylbenzoate (manufactured by Tokyo Chemical Industry Co., Ltd.): 0.18 part · Non-hydrolyzable monomer: Butyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.): 6.3 parts and styrene: 4.7 parts Subsequently, while passing nitrogen gas, the mixture was heated to 65 - 70 °C and stirred for 30 minutes. Then, as an initiator, 1.5 parts of 2,2′-azobis[N-(2-carboxyethyl)-2-methylpropionamidine] (VA-057, manufactured by Fuji Film Wako Pure Chemical Corporation) was added, and stirring was continued for 6 hours to obtain an emulsion of particles. To remove excess solutes in the obtained emulsion, ultrafiltration was performed, and concentration / filtration was repeated a total of 5 times. Thereafter, 0.13 part of 3-aminopropyltrimethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.) as a nitrogen atom source and 27.0 parts of 1,1,1,3,3,3-hexamethyldisilazane (manufactured by Kishida Chemical Co., Ltd.) as a hydrophobizing agent were added, and the mixture was stirred at 50 °C for 24 hours. Then, it was dried by spray drying to obtain an external additive 21. The physical properties of the external additive 21 are shown in Table 2.

[0112]

Table 1

[0113] 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 MA-CDMSP: 3-(Chlorodimethylsilyl)propyl methacrylate St: Styrene MAB: Butyl methacrylate Na(4-VBA): Sodium 4-vinylbenzoate NaMA: Sodium methacrylate NaPSS: Sodium p-styrenesulfonate VA-057: 2,2′-Azobis[N-(2-carboxyethyl)-2-methylpropionamidine] KPS: Potassium peroxydisulfate V-65: 2,2’-Azobis(2,4-dimethylvaleronitrile) AP-TMS: 3-Aminopropyltrimethoxysilane (aminosilane having an amino group) DMAP-TMS: [3-(N,N-Dimethylamino)propyl]trimethoxysilane (aminosilane having a dialkylamino group) IP-TMS: (3-Isocyanatopropyl)trimethoxysilane (silane having an isocyanate structure) PAA-03E: Polyallylamine (weight average molecular weight: 3000)

[0114]

Table 2

[0115] In Table 2, Si / (C + O + Si) is the ratio of the number of silicon atoms to the total number of carbon atoms, oxygen atoms, and silicon atoms in the external additive particles, and C / Si is the ratio of the number of carbon atoms to the number of silicon atoms in the external additive particles. Also, N / (C + N + O + Si) is the ratio of the number of nitrogen atoms to the total number of carbon atoms, nitrogen atoms, oxygen atoms, and silicon atoms in the surface region of the external additive particles.

[0116] <Production Example of Toner Particle 1> The following materials were premixed using a Henschel mixer and then melt-kneaded using a twin-screw extruder (trade name: PCM-30, manufactured by Ikegai Tekko Co., Ltd.) with the temperature set so that the melt temperature at the discharge port was 150°C to obtain a kneaded product. · 100 parts of amorphous polyester (propylene oxide adduct of bisphenol A / terephthalic acid = 50 / 50, number average molecular weight: 3000, acid value: 12) · 75 parts of magnetic iron oxide particles · 2 parts of Fischer-Tropsch wax (C105 manufactured by Sasol, melting point: 105°C) · 2 parts of charge control agent (manufactured by Hodogaya Chemical Co., Ltd., T-77) The obtained kneaded mixture was cooled and coarsely pulverized with a hammer mill, and then finely pulverized using a pulverizer (trade name: Turbo Mill T250, manufactured by Turbo Kogyo Co., Ltd.) to obtain finely pulverized powder. The obtained finely pulverized powder was classified using a multi-stage classifier utilizing the Coandă effect to obtain toner particles 1 having a weight average particle diameter of 7.2 μm.

[0117] <Production Example of Toner 1> The external addition of the external additive to toner particles 1 was carried out dry. 100 parts of toner particles, 1.3 parts of external additive 1, and 1.5 parts of fumed silica (BET specific surface area: 200 m 2 / g) were added to a Henschel mixer and externally mixed. Then, it was sieved with a mesh having an opening of 150 μm to obtain toner 1 to which external additive 1 was externally added.

[0118] <Production Examples of Toners 2 to 21> In the production example of toner 1, toners 2 to 21 were obtained in the same manner as in the production example of toner 1, except that external additive 1 was changed to external additives 2 to 21, respectively.

[0119] <Example 1> The following evaluations were carried out using toner 1.

[0120] <Evaluation of Toner Fluidity> The fluidity of the toner was measured by the following method.

[0121] First, using a powder tester (PT-X, manufactured by Hosokawa Micron Corporation), 3 g of toner 1 was sieved through sieves with openings of 150 μm, 100 μm, and 45 μm (plain woven wire mesh, standard JIS Z8801-1) while vibrating under the condition of an intensity of 4.0 for 10 seconds. Then, when the remaining amount of toner on the sieve with an opening of 150 μm was A, the remaining amount of toner on the sieve with an opening of 100 μm was B, and the remaining amount of toner on the sieve with an opening of 45 μm was C, the fluidity of the toner was evaluated using the fluidity index (%) represented by the following formula. The evaluation results are shown in Table 3. Those with a fluidity index of 30% or less were judged to have obtained the effects of the present invention.

[0122] Flowability index (%) = [(A + 0.6×B + 0.2×C) / measured sample mass] × 100 <Evaluation of toner flow maintenance> The evaluation of the toner flow maintenance was carried out after the above evaluation was performed.

[0123] As an image forming apparatus, HP LaserJet Enterprise M609dn (manufactured by HP) was used. Toner 1 was put into the cartridge, and 5,000 image outputs were performed under the following conditions. · Paper: GFC - 081 (81.0 g / m 2 )(Canon Marketing Japan Inc.) · Toner loading amount on paper: 0.35 mg / cm 2 · Process speed: 377 mm / second Thereafter, the remaining toner in the cartridge was taken out, and for the remaining toner, the above flowability index was calculated, and the value was taken as the flowability index after durability. Using the flowability index obtained in the above evaluation of toner flowability as the flowability index before durability, the change rate shown by the following formula was calculated, and the toner flow maintenance was evaluated using that value.

[0124] Change rate (%) = (Flowability index after durability - Flowability index before durability) / Flowability index before durability × 100 Those with a change rate of 100% or less were judged to have obtained the effects of the present invention.

[0125] <Evaluation of crushing of external additive particles and detachment from toner particles> The evaluation of the crushing of external additive particles and detachment from toner particles was carried out after the above evaluation of toner flow maintenance was performed.

[0126] After the above 5,000 image outputs, the remaining Toner 1 in the cartridge was taken out, and the surface of the taken - out Toner 1 was observed using a scanning electron microscope (S - 4800, manufactured by Hitachi High - Technologies Corporation) to obtain a SEM image. In the obtained image, when an adhered material crushed on the surface of the toner was observed, it was regarded as having crushing, and when a concave portion where the external additive particles were detached was observed on the surface of the toner, it was regarded as having detachment.

[0127] <Evaluation of Image Density Stability> Using the image forming apparatus used in the evaluation of the toner flow maintenance property, toner 1 was put into the cartridge, and 10,000 image outputs were performed under the same conditions as those set in the evaluation of the toner flow maintenance property.

[0128] During the continuous output of 10,000 sheets, calibration was not performed and the set conditions were not changed. The reflection density of all the output images was measured, and the image density stability was evaluated by the value of the standard deviation thereof. Those with a standard deviation of less than 0.100 were judged to have obtained the effects of the present invention. For the measurement of the reflection density of the images, an X-Rite color reflection densitometer (500 series: manufactured by X-Rite) was used.

[0129] <Examples 2 to 19, Comparative Examples 1 and 2> Using toners 2 to 21, the same evaluation as in Example 1 was carried out. The evaluation results are shown in Table 3. Example 4 is described as a reference example.

[0130]

Table 3

Claims

1. A method for producing externally added agent particles containing a polymer, wherein the production method comprises: a radical polymerization step of performing a radical polymerization reaction of a monomer raw material containing a compound represented by the following formula (3) using a radical polymerization initiator having a carboxy group, which is a compound represented by the following formula (2), in the presence of an emulsifier under the condition of 6.0 ≤ pH ≤ 8.0; and a condensation step of performing a hydrolysis reaction and a polycondensation reaction of the hydrolyzable group X in the following formula (3) after the radical polymerization step to obtain particles containing a polymer, and the emulsifier is any compound selected from the group consisting of a radically polymerizable carboxylic acid, a radically polymerizable carboxylate, and sodium p-styrenesulfonate, characterized in that it is a method for producing externally added agent particles. (In formula (2), R5 is an alkylene group having 1 to 12 carbon atoms.) R ６ ｍ SiX ４－ｍ ... (3) (In formula (3), X is a hydrolyzable group, m is an integer of 1 to 3, R ６ are each independently an organic group having 1 to 20 carbon atoms, and at least one of R ６ is a radically polymerizable group.)

2. The method for producing externally added agent particles according to claim 1, wherein the hydrolyzable group X in the formula (3) is an alkoxy group.

3. The method for producing externally added agent particles according to claim 1, wherein the compound represented by the formula (3) is a compound represented by the following formula (1). 【Chemical Formula 2】 (In formula (1), R １ is an alkylene group having 1 to 10 carbon atoms, R ２ , R ３ , and R ４ are each independently any of hydrogen, a methyl group, and an ethyl group, and R' is hydrogen or a methyl group.)

4. The ratio of the number of silicon atoms to the total number of carbon atoms, oxygen atoms, and silicon atoms in the external additive particles is 4.0% or more and 25.0% or less. The method for producing external additive particles according to any one of claims 1 to 3.

5. The method for producing external additive particles according to any one of claims 1 to 4, wherein the ratio of the number of carbon atoms in the external additive particles to the number of silicon atoms in the external additive particles is 6.5 or more.

6. The method for producing external additive particles according to any one of claims 1 to 5, comprising a step of surface-treating the particles containing the polymer with an amine compound.

7. The method for producing external additive particles according to claim 6, wherein the amine compound is an aminosilane.

8. When X-ray photoelectron spectroscopy is performed on the surface of the external additive particles, The ratio of the number of nitrogen atoms to the total number of carbon atoms, nitrogen atoms, oxygen atoms, and silicon atoms is 1.0% or more and 2.5% or less. The method for producing external additive particles according to any one of claims 1 to 7.

9. When the 50% particle size based on the volume distribution of the external additive particles is defined as D50, The method for producing external additive particles according to any one of claims 1 to 8, wherein the D50 is 50 nm or more and 200 nm or less.

10. The method for producing an external additive according to any one of claims 1 to 9, wherein the emulsifier is sodium 4-vinylbenzoate, sodium methacrylate, or sodium p-styrenesulfonate.

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