JP2002351153A - Method of manufacturing coated carrier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing coated carriers which broadly deals with prescriptions of coating agents satisfying desired characteristics, are small in differences between coating amounts and coating states among carrier particles and is capable efficiently performing coating. SOLUTION: The method of manufacturing the coated carriers having at least core particles and the coating resins has a process step of forming a dispersion system prepared by dispersing the core particles into a polymerized medium which does not dissolve the coating resins and a process step of forming the coating resin layers on the surfaces of the core particles by polymerizing a vinyl polymerizable monomer constituting the coating resins.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a coated carrier used in electrophotography, electrostatic recording, and the like, and more particularly to a method for producing a two-component developer by dry-coating a carrier. The present invention relates to a method for manufacturing a carrier.

[0002]

2. Description of the Related Art In a process of developing an electrostatic latent image such as an electrophotographic method, an image is formed on an electrostatic latent image by using charged toner particles by utilizing an electrostatic interaction of the electrostatic latent image. It is. In general, one of the methods for developing such an electrostatic latent image using toner is to develop the non-magnetic toner by pressing the toner on a developer carrier with a regulating member or the like to charge the toner, or dispersing the magnetic material in the resin. On the other hand, there is a two-component developer in which a non-magnetic toner is dispersed in a medium called a carrier. Is preferably used, and the latter is preferably used in a full-color copying machine requiring high image quality.

In recent years, in order to obtain high quality images, the toner particle size has been reduced. However, on the other hand, if the load due to the carrier is large when the developer is used for a long period of time, the durability of the developer tends to deteriorate when the small particle size toner is used, and the image quality tends to deteriorate accordingly. Therefore, when a developer using a small particle size toner is used for a long period of time, the characteristics required for the carrier to maintain a high quality image include appropriate charging properties, pressure resistance to an applied electric field, and shock resistance. Properties, spent resistance, abrasion resistance, developability, productivity, etc., and it is particularly important to reduce the load on the developer.

In recent years, with the development of computers, high-definition televisions, and the like, means for outputting higher-definition full-color images has been demanded. For this purpose, efforts have been made to further enhance the quality and definition of full-color copied images.

In response to such demands, studies have been made from various viewpoints such as processes and materials. For example, in the electrophotographic process, a method of changing an image from analog processing to digital processing, or a method of applying an AC bias at the time of development to finely vibrate the developer brush can be used. As for the developer, a method for reducing the particle size of the toner and the carrier can be used.

Here, the reduction of the particle size of the carrier is determined by the carrier 1
The magnetism of the individual is reduced, the brush of the developer brush can be made thinner and denser, the sweeping of the magnetic brush during development can be reduced, and the density of toner on the latent image carrying surface can be increased. Contributes to high image quality and high definition, but on the other hand, the carrier is developed and adhered on the image portion or non-image portion of the latent image carrier because the magnetic binding force by the developer carrier is reduced, so-called Carrier adhesion occurs.

To prevent this, attempts have been made to increase the resistance of the magnetic carrier. For example, as disclosed in JP-B-5-8424, the specific resistance of the magnetic carrier is set to 10 ^13.
It is described that carrier adhesion can be reduced by setting the resistance to Ωcm or more. However, according to our study, even when a magnetic carrier having a specific resistance of 10 ¹³ Ωcm or more is used, the core can be sufficiently exposed when the core is exposed or the coating material comes off due to long-term repeated use. In some cases, it could not be prevented.

As described above, coating of a magnetic carrier with a coating resin is very important for preventing carrier adhesion to be sufficiently satisfied, particularly when the carrier is reduced in particle size, and for obtaining a high-definition image. .

On the other hand, the characteristics required for the coated carrier to maintain the high-definition image for a long period of time together with the initial period include appropriate charging properties, pressure resistance to an applied electric field, impact resistance, and the like. Spent resistance, wear resistance, and the like. Therefore, in the coated carrier, the selection of the core particles, the coating resin, and the coating method is important to satisfy the above-mentioned required characteristics.

Conventionally, as a method of coating a carrier, a method of dissolving a coating resin in a solvent, adding the solution to a core and stirring while heating, and forming a fluidized bed of core particles and coating the coating resin solution therewith And a dry coating method in which the coating resin is directly fixed to the surface of the core particles, and a polymerization coating method in which the resin is directly polymerized on the surface of the core particles to form a coating layer.

In the above-mentioned wet coating method, a uniform film can be formed in the coating process, but binding between carriers occurs in the drying process, and it is necessary to crush this before use. For this reason, a part of the core surface is exposed and a uniform image cannot be obtained, or the coating resin is peeled off after a long use, resulting in a problem such as a decrease in density and an increase in fog. In addition, there is a problem that a good coat cannot be formed on a resin that is hardly soluble in a solvent or a resin that has poor wettability with a core. In particular,
It was not possible to add a crosslinking component to the coating resin in order to improve the strength of the coating film after coating, because the coating resin would not be dissolved in the solvent. Further, it was not possible to coat the surface of a core which is easily dissolved in a solvent like a magnetic material-dispersed resin carrier.

A dry coating method is disclosed in JP-A-6-3179.
No. 37 discloses a method in which resin particles and the like are coated on magnetic particles in a dry manner by mechanical impact. However, compared with a wet coating method, the resin particles are easily dissolved in a solvent such as a magnetic material-dispersed resin core. When coating on the material surface or when coating with a coating resin or the like that has poor wettability with the core material, the core particles and coating resin can be selected in a wide range, but mixing failure due to scattering of the material due to agitation tends to occur. In addition, there is a problem that a coating amount and a coating state vary greatly between carrier particles, and it is difficult to form a uniform film, and the coating resin is peeled off after a long use.

On the other hand, the polymerization coating method is disclosed in Japanese Patent Laid-Open No. 2-187.
As disclosed in Japanese Patent Publication No. 770, a method of forming an olefin coating layer by polymerizing an olefin monomer in a dry manner. As described above, this method has few problems such as the core surface being exposed and a large change in the coating state between carrier particles, but the resin that can be coated is limited to olefin, and the desired design concept is desired. It was not a production method that could be applied to the prescription according to.

Japanese Patent Application Laid-Open No. 11-2926 discloses that
There has been proposed a method for producing a carrier in which a photoreactive group is introduced into a core particle, and a monomer is radically polymerized from the photoreactive group to form a coat layer. However, according to the study by the present inventors, there was a problem that the core particles close to the light emitting source could not uniformly irradiate light into the system while being shielded from light, and the polymerization reaction did not proceed uniformly. Further, the coating resin was polymerized in a polymerization medium in which the coating resin was dissolved, which was substantially the same as the above-mentioned wet coating method.

As described above, there is no method for producing a sufficiently durable coated carrier for preventing carrier adhesion, particularly when the particle size of the coated carrier is reduced, in order to improve the image quality particularly in full-color development. Was.

[0016]

SUMMARY OF THE INVENTION An object of the present invention is to provide a coated carrier which solves the above-mentioned problems, can widely cope with the formulation of a coating agent which satisfies desired characteristics, and can be coated efficiently. It is to provide a manufacturing method of.

Another object of the present invention is to provide a coating resin on the surface of the core particles so as to satisfy various properties such as appropriate charging properties, pressure resistance to an applied electric field, resistance to snagging, resistance to spent and abrasion resistance. It is an object of the present invention to provide a method for producing a coated carrier which is uniformly coated, has a small difference in coating amount and coating state between carrier particles, and has sufficient durability even in repeated use.

Another object of the present invention is to efficiently coat a coated carrier containing a cross-linking component, which remarkably improves the strength of a coated film after coating, in an arbitrary composition regardless of the content of the cross-linking component. It is an object of the present invention to provide a method for manufacturing a coated carrier that can be used.

Another object of the present invention is to provide a method for producing a coated carrier which can uniformly and stably coat core particles which are easily dissolved in a solvent, such as magnetic material-dispersed resin particles. is there.

[0020]

According to the present invention, there is provided a method for producing a coated carrier having at least core particles and a coating resin, wherein the coating medium is not dissolved in a coating medium.
Forming a dispersion system in which the core particles are dispersed, in the dispersion system, polymerizing a vinyl polymerizable monomer constituting the coating resin, and forming the coating resin layer on the surface of the core particles. The present invention relates to a method for manufacturing a coated carrier.

[0021]

DETAILED DESCRIPTION OF THE INVENTION The inventors of the present invention have conducted intensive studies to overcome the above-mentioned problems in the prior art, and as a result, have found that a dispersion system in which core particles are dispersed in a polymerization medium which does not dissolve the coating resin for coating the surface is disclosed. In the above, by forming a resin layer directly on the surface of the core particles by polymerizing the vinyl polymerizable monomer constituting the coating resin, there is no variation in the coverage or coating state between the carrier particles, and in various coating resins The present inventors have found that a versatile and highly versatile surface modification is achieved, and have completed the present invention.

That is, according to the present invention, since the production of the coating resin and the coating on the surface of the core particles are performed at the same time, the composition of the coating resin depends on the properties such as solubility of the coating resin in a solvent and moldability as in the prior art. Without being restricted, a coat layer having an arbitrary composition can be formed uniformly on the surface of the core particles. In addition, by using a polymerization medium in which the coating resin formed by polymerization does not melt, during the polymerization reaction, or in the washing and drying steps, the carrier particles are not bound to each other, and the coat having a smooth surface is maintained. A carrier can be manufactured.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The manufacturing method of the present invention will be described below in order.

The core particles are dispersed in an aqueous or hydrophilic medium, and a polymerizable monomer is added thereto for polymerization.

In the present invention, the aqueous or hydrophilic medium is
Shows water, alcohols, ketones, ethers, esters, or mixtures thereof. Specifically, for example,
Water, methanol, ethanol, 1-propanol, 2-
Propanol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, 1-
Pentanol, 2-pentanol, 3-pentanol,
2-methyl-1-butanol, isopentyl alcohol, tert-pentyl alcohol, 1-hexanol, 2-methyl 1-pentanol, 4-methyl-2-pentanol, 2-ethylbutanol, 1-heptanol, 2-heptanol Alcohols such as methyl, 3-heptanol, 2-octanol, 2-ethyl 1-hexanol, benzyl alcohol and cyclohexanol; ether alcohols such as methyl cellosolve, cellosolve, isopropyl cellosolve, butyl cellosolve, diethylene bricol monobutyl ether; acetone, methyl ethyl ketone Ketones such as acetic acid, methyl isobutyl ketone and cyclohexanone; esters such as ethyl acetate, butyl acetate, ethyl propionate and cellosolve acetate;
Ethers such as ethyl ether, dimethyl ether and trioxane tetrahydrofuran can be exemplified.

In the present invention, the above-mentioned dispersion medium is preferably a solvent in which the core particles and the coating resin formed by polymerization are not dissolved, and more preferably water. This is because the coating efficiency is improved because the coating resin formed by polymerization is selectively adsorbed on the core particle surface. Further, the above-described dispersion medium may contain a dispersant such as a surfactant or a polymer dispersant.

It is preferable that a step of adjusting the amount of dissolved oxygen in the system to be within 2 vol% before the step of polymerizing the vinyl polymerizable monomer. By controlling the amount of dissolved oxygen, polymerization proceeds uniformly, coating efficiency is improved, and variations in the coating amount between carrier particles and variations in the coating state between lots can be suppressed.

The method of adjusting the amount of dissolved oxygen includes, for example, (1) a method in which various inert gases such as helium, nitrogen, and argon are released into the liquid of the polymerization reaction system and replaced with the same. ) There is a method of deoxygenation by ultrasonic irradiation. These may be used alone or in combination.

In the case of using the above method (1), it is preferable to insert a gas introduction tube into the reaction medium of the polymerization reaction system and perform bubbling through the introduction tube. As a gas used for replacing oxygen, any gas can be used as long as it does not contain oxygen, is soluble in the reaction medium, and has no polymerization inhibition property. Specifically, an inert gas such as helium, nitrogen, or argon can be used alone or as a mixture.

The flow rate of the gas into the polymerization reaction system depends on the type of gas, the temperature, and the volume of the reaction medium, but is preferably from 5 vol% / min to 10 vol% of the volume of the reaction vessel per minute.
At a flow rate of 0 vol% / min, the amount of gas introduced before the start of the polymerization reaction is preferably 2 to 30 times the volume of the reaction vessel.

It is preferable to continue the replacement with the inert gas as described above during the polymerization reaction.

When the method (2) is used, an ultrasonic wave is applied directly to the polymerization reaction system. As an ultrasonic wave applying device,
An ordinary ultrasonic cleaning machine or ultrasonic homogenizer can be used.

In the present invention, during the polymerization reaction, stirring may be performed to such an extent that settling of the base particles is prevented. The polymerization is carried out at a polymerization temperature of 40 ° C. or higher, generally 50 to 90 ° C. Further, the temperature may be raised in the latter half of the polymerization reaction. After the completion of the reaction, the product is washed, dried, and collected.

As the vinyl polymerizable monomer that can be used in the present invention, a known vinyl polymerizable monomer can be used. Specifically, for example, styrene, α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert -Butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, p-methoxystyrene, p-phenylstyrene, etc. Styrene polymerizable monomer; methyl acrylate, ethyl acrylate, n-propyl acrylate,
iso-propyl acrylate, n-butyl acrylate, iso-butyl acrylate, tert-butyl acrylate, n-amyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, n-nonyl acrylate, cyclohexyl acrylate, benzyl acrylate Acrylic polymerizable monomers such as dimethyl phosphate ethyl acrylate, diethyl phosphate ethyl acrylate, dibutyl phosphate ethyl acrylate, and 2-benzoyloxyethyl acrylate; methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, and iso-propyl methacrylate , N-butyl methacrylate, iso-butyl methacrylate, t
tert-butyl methacrylate, n-amyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, n-
Methacrylic polymerizable monomers such as nonyl methacrylate, diethyl phosphate ethyl methacrylate, dibutyl phosphate ethyl methacrylate; methylene aliphatic monocarboxylates; vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate, vinyl benzoate , Vinyl esters such as vinyl formate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether; vinyl polymerizable monomers such as vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and vinyl isopropyl ketone; Is mentioned.

The amount of the above-mentioned monomer can be used in an arbitrary amount depending on various factors such as polymerization conditions and a desired composition of the coating layer. It is preferable to use it in the range of 0.01 to 100% by mass.

In the present invention, it is preferable to use a crosslinking agent together with the above-mentioned polymerizable monomer. Conventionally, it has been difficult to use a crosslinked resin as a coating resin because of problems of solubility and moldability.However, using the method of the present invention, it is possible to form a resin layer having an arbitrary crosslink point. As a result, the strength of the coat layer can be significantly improved.

As the crosslinking agent that can be used in the present invention, any known crosslinking agent can be used as long as it has two or more unsaturated double bonds. Specifically, for example, aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene, ethylene glycol diacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, Methylolpropane triacrylate, trimethylolpropane trimethacrylate,
1,4-butanediol diacrylate, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol dimethacrylate, pentaerythritol tetramethacrylate, glycerol acroxydimethacrylate, N, N-cyvinylaniline, divinyl ether, divinyl sulfide, divinyl sulfone and the like can be mentioned. These cross-linking agents may be used alone, or two or more of them may be used as an appropriate mixture. These cross-linking agents may be used by mixing with the polymerizable monomer in advance, or may be added during the polymerization reaction of the polymerizable monomer.

The amount of the cross-linking agent used may be any amount depending on various factors such as polymerization conditions and desired composition of the coating layer. It is preferably used in the range of 0.01 to 30% by mass. If the amount is less than 0.01% by mass, sufficient strength due to crosslinking may not be obtained. Further, in a range exceeding 30% by mass, the polymerization conversion rate becomes small due to the high crosslinking density, and the strength of the coat layer may become fragile at all.

In the present invention, in the step of dispersing the core particles, a hydrophilic portion, a hydrophobic portion,
It is preferable to use a polymerization initiator having a reactive site therebetween. In order to disperse the core particles in an aqueous or hydrophilic medium, it is preferable to use a dispersing agent. At this time, by using a polymerization initiator having polymerization initiating ability and dispersing ability in one molecule, excess dispersing agent can be used. No need to use agents
The place where the polymerization of the polymerizable monomer is started in the polymerization reaction system is controlled on the surface of the core particle, the by-product of the fine powder is suppressed, and the coating can be performed efficiently.

In the present invention, the above-mentioned polymerization initiator having a hydrophilic site, a hydrophobic site, and a reactive site therebetween is preferably a compound represented by the following formula (1).

R ¹ -XZYR ² (1) wherein R ¹ is a hydrophobic group, R ² is a hydrophilic group,
Z is a reactive group, and X and Y are each the aforementioned R ¹
Or a unit for bonding R ² and Z. )

R ¹ is an aliphatic hydrocarbon group having 5 to 60 carbon atoms, an aromatic hydrocarbon group having 6 to 60 carbon atoms, a heterocyclic group, a polysiloxane residue, etc., and R ² is a polysaccharide group, a polyether group or the like. Group, hydroxyl group, sulfate group, sulfonic acid group, carboxyl group, phosphate group, phosphonium group, heterocyclic group or amino group, salts thereof and the like, Z is a polyvalent group,
X and Y are the same or different units having a bond such as a carbon-carbon bond, an ester bond, an amide bond, an ether bond, a urethane bond, a urea bond, and X and Y
May have a reactive site. The reactive site of the unit represented by X and Y is usually a group that generates a radical, a cation or an anion by heat or light (for example, an azo group, a peroxide group, a diketo group, and the like).

More preferably, it is represented by the following formula (2).

R ^1a -A ¹ -R ³ -N = NR ⁴ -A ² -R ^2a (2) (wherein, R ^1a is a long-chain aliphatic hydrocarbon group having 6 to 30 carbon atoms or carbon number. 6-1 carbon atoms having 1-20 alkyl groups
An aryl group of 2 (excluding the alkyl moiety), R ^2a
Is a carboxyl group, a carboxylate, a sulfate group, a sulfate group, a sulfonic group, a sulfonic group having a salt structure, and an aliphatic group having 1 to 20 carbon atoms having at least one of these groups as a substituent or R ³ and R ⁴ are the same or different and are an alkylene group having an electron-withdrawing group at a carbon atom adjacent to the azo group;
¹ represents nothing or at least one bond selected from an ester bond, an amide bond, a urethane bond and an ether bond, and A ² represents nothing or an ester bond, an amide bond, a urethane bond. And at least one bond selected from a bond and an ether bond. )

In the polymerization initiator used in the present invention, the hydrophobic portion (hydrophobic group) represented by R ¹ in the above formula (1) includes an aliphatic hydrocarbon group, an aromatic hydrocarbon group, and a heterocyclic group. And polysiloxane residues. These hydrophobic groups may be used alone or in combination of two or more.

As the aliphatic hydrocarbon group, a saturated or unsaturated linear or branched aliphatic hydrocarbon group [eg, hexyl, pentyl, 2-ethylhexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl (lauryl) ) 5 to 60 carbon atoms such as tridecyl, tetradecyl, pentadecyl, hexadecyl (cetyl), heptadecyl, octadecyl, nonadecyl, eicosyl, docosyl, hexacosyl (seryl) triacontyl, hentria contyl (merisyl), α-olefin polymer, etc. 6 to 30) alkyl groups, hexenyl, tridecenyl, octadecadienyl, octadecenyl, nonadecenyl, docosenyl, hexacosenyl, α-olefin polymers (olefin oligomers having unsaturated double bonds) and 5 to 60 carbon atoms (olefins). Good And preferably 5 to 6 carbon atoms such as alkenyl group of 6 to 30), hexynyl and nonadecinyl.
0 (preferably 6 to 30) alkynyl group or the like], saturated or unsaturated cyclic aliphatic hydrocarbon group [for example, having 6 carbon atoms such as cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclodecyl, cyclododecyl, cyclopentadecyl and the like] To 60 (preferably 6 to 20) cycloalkenyl groups or the like], saturated or unsaturated polycyclic hydrocarbon groups [for example, groups corresponding to bicyclic hydrocarbons such as carane, pinane, bornane, norpinane and norbornane ( A crosslinked monocyclic saturated or unsaturated hydrocarbon group), a group corresponding to a tricyclic hydrocarbon such as adamantane (bridged polycyclic saturated or unsaturated hydrocarbon), etc.].

Examples of the aromatic hydrocarbon group include phenyl, naphthyl, biphenyl, fluorenyl, anthracenyl,
Phenanthrenyl, benzanthrenyl, pyrenyl,
Aryl groups such as triphenylel and perylenyl, isopropylphenyl, butylphenyl, amylphenyl, hexylphenyl, octylphenyl, nonylphenyl,
Examples thereof include an alkyl-aryl group such as decylphenyl, dodecylphenyl, and tetradecylphenyl, and preferably have 6 to 60 carbon atoms.

As the heterocyclic group, 12-crown-4,
15-crown-5, 18-crown-6, dicyclohexano-24-crown-8, dibenzo-18-crown-6, cyclen, hexacyclene, 1-aza-12-
Crown ethers such as crown-4, 1-aza-15-crown-5, 1-aza-18-crown-6; oxygen or hetero atom such as tetraoxadiazacyclooctadecane, pentaoxadiazabicyclotricosan or the like; Heterocyclic compounds having a nitrogen atom; ethioporphyrin, octaethylporphyrin, protoporphyrin,
Porphyrins such as hematoporphyrin, coproporphyrin, mesoporphyrin and tetraphenylporphyrin; phthalocyanine, naphthalocyanine and the like.

The heterocyclic group may hold a metal in the skeleton. Examples of the metal include an alkali metal such as lithium, sodium and potassium, an alkaline earth metal such as magnesium, and a periodic table such as aluminum and gallium. 3B
Group 4B metals of the periodic table such as metal, silicon, tin, and lead, and transition metals such as vanadium, manganese, iron, cobalt, nickel, ruthenium, copper, and zinc. Also,
Anions for these metals may coexist, and examples of the anion include a halogen ion, an organic acid ion (such as an acetate ion), an inorganic acid ion (such as a sulfate ion), a tetrafluoroboron ion, and a hexafluorophosphate ion.

The polysiloxane residue includes, for example, a group represented by the following formula.

CH _3- (Si (CH ₃ ) ₂ O) p- (wherein p is an integer of 5 to 30, preferably 10 to 20)

The hydrophobic group includes a composite hydrophobic group in which different types of hydrophobic groups are bonded to each other.

These hydrophobic groups may have various substituents. Examples of the substituent include a carbonyl group, a thiocarbonyl group, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom), a hydroxyl group, a mercapto group, an oxime group, an imino group, an isocyanato group (isocyanate group), and a thioisocyanato group ( Thioisocyanate group), cyano group, tertiary amino group, nitro group, carboxyl group, chain hydrocarbon group (alkyl group having 1 to 12 carbon atoms), monocyclic aliphatic hydrocarbon group (3 carbon atoms) To 16 cycloalkyl groups). For example, perfluorophenyl, perfluoropentyl, perfluorododecyl and the like may be used.

Preferred hydrophobic groups include groups which sufficiently exhibit a hydrophobic function as a surfactant, for example, nonyl,
C1-C30 long-chain aliphatic hydrocarbon groups such as dodecyl (lauryl), tetradecyl, hexadecyl (cetyl), and octadecyl; carbon atoms 1 such as octylphenyl, nonylphenyl, decylphenyl, dodecylphenyl
And an aryl group having 6 to 20 carbon atoms having an alkyl group of 20 to 20 (particularly preferably -phenyl group having alkyl having 1 to 18 carbon atoms).

As the hydrophilic site (hydrophilic group) represented by R ² , a nonionic group (for example, polysaccharide group, hydroxyl group), an anionic group (for example, sulfate group, sulfate group, sulfonic group, Carboxyl group, carboxylate, phosphate group, phosphate), cationic group (for example,
A heterocyclic group, a heterocyclic salt, an amino group or an ammonium salt). These hydrophilic groups may be used alone or in combination of two or more.

Examples of the polysaccharide group include sucrose ester, sorbitol, sorbitol, sorbitan, and sorbitan ester residues.

When the hydrophilic group represented by R ² is an anionic group (such as carboxylic acid or sulfonic acid), it may form a salt with various bases. Examples of the base include inorganic bases (for example, alkali metals such as lithium, sodium, and potassium, alkaline earth metals such as magnesium, and ammonia), and organic bases (for example, amines).

The heterocyclic group includes a group corresponding to a 5- to 8-membered heterocyclic ring containing at least one atom selected from a nitrogen atom, an oxygen atom and a sulfur atom as a hetero atom. Particularly, a quaternary ammonium salt of a heterocyclic group having a nitrogen atom as a hetero atom, for example, a heterocyclic group represented by the following formula can be mentioned.

[0059]

Embedded image (In the formula, R ⁵ represents an alkyl group.)

Examples of the alkyl group represented by R ⁵ include C ₁ -C ₆ lower alkyl groups such as methyl, ethyl, propyl and hexyl.

The amino group includes a primary to quaternary amino group. In the case of a primary or secondary amino group, an inorganic acid (for example,
It may form a salt or amide with hydrochloric acid or the like or an organic acid (eg acetic acid or the like). Examples of the secondary to quaternary amino groups include alkylamino groups having 1 to 30 carbon atoms such as methylamino group, dimethylamino group, diethylamino group, trimethylamino group, tetramethylamino group, and trimethyllauryl group; phenylamino group, diphenylamino It may be an arylamino group having 6 to 12 carbon atoms such as a group. In addition, a cationic group (especially an amino group) may form an amphoteric ionic group together with an anionic group (especially a carboxyl group or a sulfate group). Examples of such a group forming an amphoteric ion include a carboxyethylamino group, a dihydroxymethylamino group, a dicarboxyethylamino group, and an aminosulfate group.

The hydrophilic group represented by R ² may be substituted with various substituents. Examples of the substituent include the above-mentioned substituents of the hydrophobic group. The hydrophilic group also includes a composite hydrophilic group in which different types of hydrophilic groups are bonded to each other.

Preferred hydrophilic groups include hydrophilic groups that sufficiently fulfill the role of hydrophilicity as a surfactant, for example, carboxyl groups, sulfate groups, sulfonic groups, salts thereof, and polyether groups. Can be

In the above formula (1), Z is an azo group, and X and Y are the same or different units each having a carbon-carbon bond, an ester bond, an amide bond, an ether bond, a urethane bond, a urea bond or the like. Yes, X and Y
It is preferable that either one of these has an electron withdrawing group.

The units X and Y are represented by R ¹ or R ² and Z
Is determined according to the type of X and Y are units having a bond formed by a reaction between the terminal of R ¹ or R ^{2 and} the terminal of Z, and the type of the bond is carbon-
Carbon bond, ester bond, amide bond, ether bond,
Examples include a urethane bond and a urea bond. For example,
When ^one end of R ¹ or R ² and Z is a carboxyl group and the other end is a hydroxyl group, X has an ester bond. When one end of R ¹ or R ² and Z is a hydroxyl group and the other end is an isocyanate group, X is a urethane bond, ^one end of R ¹ or R ² or Z is an amino group, and the other end is an amino group. When the terminal is a carboxyl group, X has an amide group. Further, when ^one end of R ¹ or R ² and Z is an amino group and the other end is an isocyanate group, X has a urea bond.

The units X and Y preferably each have an electron-withdrawing group. Usually, the reactive group Z
Is a radical generating group, and in order to stabilize the reactive group Z, a carbon atom adjacent to the reactive group has an electron-withdrawing group (for example, a cyano group, a halogen group, an amino group, etc.). Is preferred.

In the above formula (1), when the reactive group Z is an azo group (-N = N-), the units X and Y are usually
It is an alkylene group having 2 to 4 carbon atoms (including a methylene group) having a methyl group and a cyano group at a carbon atom adjacent to the azo group. When the reactive group Z is a peroxide group (—O—O—), the units X and Y usually have an alkylene group having a methyl group at a carbon atom adjacent to the peroxide group (for example, 1,1-dimethyl-1). -Phenylmethyl group, 1,1-dimethylethyl group, etc.). When the reactive group Z is an ester-type peroxide group (—C (＝ O) —O—O—C (＝ O) —),
The units X and Y may be a phenyl group or a long-chain alkyl group (eg, a lauryl group), and the reactive group Z is a diketo group (—C (＝ O) —C (＝ O) —). ,
Units X and Y may be phenyl groups.

In the above formula (2), examples of the alkylene group represented by R ³ and R ⁴ include those having 1 to 6 carbon atoms such as methylene, ethylene, propylene and tetramethylene.
An alkylene group having 2 to 6 carbon atoms is preferable.

More preferably, in the above formula (2), R ^1a is a long-chain aliphatic hydrocarbon group having 10 to 22 carbon atoms, or phenyl having an alkyl group having 1 to 18 carbon atoms as a substituent. Group, R ^2a is a carboxyl group, a carboxylate, a sulfate group, a sulfate, a sulfonic acid group, a sulfonic acid group having a salt structure, and a carbon number of 1 to 20 having at least one of these groups as a substituent. An aliphatic or aromatic hydrocarbon group having 6 to 20 carbon atoms, R ³ and R ⁴ are
The same or different, an alkylene group having 2 to 6 carbon atoms having a cyano group at a carbon adjacent to an azo group, A ¹ is a group having no or at least one bond selected from an ester bond and an amide bond; In the formula, A ² is at least one bond selected from nothing or an ester bond and an amide bond.

The method for producing the polymerization initiator of the present invention includes:
There is no particular limitation, as long as the compound obtained by the reaction has sites corresponding to the aforementioned R ¹ , R ² , X, Y and Z groups. For example, the compounds corresponding to the above R ¹ , R ² , X, Y and Z groups may be reacted sequentially, respectively, to form a group -X-
A compound corresponding to R ¹ (for example, alkylphenol and the like) and a compound corresponding to the group -ZYR ² (for example,
(E.g., a compound having an azo group and having a carboxyl group at the terminal). Further, a compound corresponding to the group -XR ¹ (for example, nonylphenol), a compound corresponding to the group -YR ² (for example, a compound having an azo group and having a carboxyl group at a terminal), and a group- You may make it react with the compound (for example, hydroxycarboxylic acid etc.) corresponding to Z-. Therefore,
Compounds corresponding to the X, Y, and Z groups often have a group (such as a carboxyl group, a hydroxyl group, an amino group, or an isocyanate group) corresponding to the bond exemplified in the above X and Y at the terminal. . Examples of the compound corresponding to the group -Z- include a polyhydric alcohol, a polycarboxylic acid, a hydroxycarboxylic acid, a polyamine, and a polyisocyanate.

In the present invention, when the above-mentioned polymerization initiator having a hydrophilic site, a hydrophobic site and a reactive site therebetween is used, the amount of the polymerization initiator used depends on the polymerization conditions and the desired toner. Can be used in an arbitrary amount depending on various factors of the composition of the polymer. However, it is generally preferable to use 0.001 to 10% by mass with respect to the core particles. If the amount is less than 0.001% by mass, a sufficient effect as a dispersant is not exhibited, and the coating state between carrier particles may vary. If the content exceeds 10% by mass, fine particles may be produced as by-products, and the efficiency of coating may be reduced.

In the present invention, known polymerization initiators can be used in combination or alone with the above-mentioned polymerization initiator having a hydrophilic site, a hydrophobic site, and a reactive site therebetween. Specifically, for example, 2,2'-azobis- (2,
4-divaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis (cyclohexane-1
Azo or diazo polymerization initiators such as -carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile and azobisisobutyronitrile;
Examples include peroxide polymerization initiators such as benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyloxy carbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, and lauroyl peroxide.

In the present invention, a known dispersion stabilizer may be used in combination or alone with the above-mentioned polymerization initiator having a hydrophilic site, a hydrophobic site, and a reactive site therebetween.
Specifically, for example, as inorganic compounds, tricalcium phosphate, magnesium phosphate, zinc phosphate, aluminum phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, and calcium sulfate , Barium sulfate bentonite, silica, alumina and the like. Examples of the organic compound include polyvinyl alcohol, gelatin, methylcellulose, methylhydroxypropylcellulose, ethylcellulose, sodium salts of carboxymethylcellulose, polyacrylic acid and its salts, polymethacrylic acid and its salts, sodium dodecylbenzene sulfate,
Examples thereof include sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, sodium octylate, sodium laurate, sodium stearate, and calcium oleate.

As the core particles used in the present invention, any known carrier particles can be used.
Specifically, for example, magnetic metals such as iron, nickel, and cobalt, and alloys thereof, or alloys containing rare earth elements, iron-based alloys, for example, iron-silicon-based, iron-
Carrier particles containing an aluminum-based, iron-silicon-aluminum-based, permalloy alloy, or the like, and a coated carrier in which a coating layer is provided on the carrier particles can be used as the core particles.

Further, magnetic material-dispersed resin particles obtained by dispersing fine particles of the above-mentioned inorganic particles having magnetism in a resin can be used as a core. In this case, the method for producing the core material includes a method of melting and kneading a binder resin, a magnetic material, and the like, and pulverizing and classifying the material, and a method of directly polymerizing a solution in which a monomer, a magnetic material, and the like are dispersed, and the like. Although it can be obtained by various production methods, among them, a curing monomer,
Magnetic material-dispersed resin particles produced by directly polymerizing a magnetic material can be preferably used. The magnetic material contained in the core particles having a horizontal Feret particle size of 1.0 μm or less can be preferably used in consideration of desorption of the magnetic material, and more preferably a magnetic material having a particle size of 0.5 μm or less. The use can increase the strength. Further, as the resin contained in the core material, any thermoplastic resin or thermosetting resin can be used.

Specific examples of the binder resin used for the above-mentioned magnetic material-dispersed resin particles include acrylic resins such as polystyrene, polymethyl methacrylate, and styrene-acrylic acid copolymer, styrene-butadiene copolymer, and ethylene. -Vinyl acetate copolymer, vinyl chloride, vinyl acetate, polyvinylidene fluoride resin, fluorocarbon resin, perfluorocarbon resin, solvent-soluble perfluorocarbon resin, polyvinyl alcohol, polyvinyl acetal, polyvinylpyrrolidone, petroleum resin, cellulose, cellulose acetate, cellulose nitrate , Cellulose derivatives such as methylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, novolak resin, polyethylene, saturated alkyl polyester resin , Aromatic polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyacrylate, polyamide resins, polyacetal resins, polycarbonate resins, polyether sulfone resins, polysulfone resins, polyphenylene sulfide resins, polyether ketone resins; Resin, modified phenolic resin, maleic resin, alkyd resin, epoxy resin, acrylic resin, polyester resin, urea resin, melamine resin, urea-melamine resin, xylene resin, toluene resin, guanamine resin, melamine-guanamine resin, acetoguanamine resin, Griptal resin, furan resin, silicone resin,
Examples thereof include a polyimide resin, a polyamideimide resin, a polyetherimide resin, and a polyurethane resin.

Hereinafter, methods for measuring various physical properties will be described.

(Measurement of Particle Size of Carrier) A particle size of 0.1 μm was randomly determined by a scanning electron microscope (100 to 5,000 times).
Photographs extracted from 200 or more carrier particles of m or more are magnified, and the magnified photographic image is placed on a tablet (manufactured by Wacom) connected to a computer, and the horizontal Feret diameter of the particles is measured manually. Diameter. Also,
The number average particle diameter and the standard deviation σ are calculated by a computer, and the cumulative ratio of 1/2 or less of the number average particle diameter is calculated from the number-based particle size distribution measured under these conditions. Calculate the cumulative value below the double diameter cumulative distribution.

(Measurement of Specific Resistance of Carrier) The measurement is performed by using a measuring apparatus shown in FIG. In the measuring device shown in FIG.
Indicates a lower electrode, 22 indicates an upper electrode, 23 indicates an insulator, 24 indicates an ammeter, 25 indicates a voltmeter,
26 indicates a constant voltage device, 27 indicates a measurement sample,
29 indicates a guide ring, and E indicates a resistance measuring cell.

The cell E is filled with carrier or core particles, and the electrode 2 is contacted with the filled carrier or core particles.
1 and 22 are arranged, a voltage is applied between the electrodes, and a current flowing at that time is measured to obtain a specific resistance. In the above measuring method, since the carrier or the core particles are powder, a change occurs in the filling rate, which may cause a change in the specific resistance. The conditions for measuring the specific resistance in the present invention are as follows: the contact area S between the filled carrier or the core particles and the electrode is about 2.3 cm ² , and the thickness d is about 2
mm, load 180 g on the upper electrode 22, applied voltage 100V
And

(Measurement of Particle Size of Metal Oxide) The number average particle size of the metal oxide was determined at random by using a photographic image magnified 5000 to 20,000 times with a transmission electron microscope H-800 manufactured by Hitachi, Ltd. 300 particles or more having a particle diameter of 0.01 μm or more are extracted, and the ferrite diameter in the horizontal direction is measured as a metal oxide particle diameter by an image processing analyzer Luzex3 manufactured by NIRECO CO., LTD. Calculate the particle size.

(Measurement of Specific Resistance of Metal Oxide) The measurement is performed according to the method of carrier specific resistance. The cell E of FIG. 1 is filled with a metal oxide, electrodes 21 and 22 are arranged so as to be in contact with the filled metal oxide, a voltage is applied between the electrodes, and a current flowing at that time is measured. Find the specific resistance. When filling the metal oxide, the filling is performed while the upper electrode 21 is rotated left and right so that the electrode uniformly contacts the sample. In the above measurement method, the specific resistance was measured under the following conditions: the contact area S between the filled metal oxide and the electrode was about 2.3 cm ² ;
mm, the load of the upper electrode 22 is 1.76 N (180 g), and the applied voltage is 100 V.

[0083]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

[Preparation Example 1 of Polymerization Initiator] 5.6 g of 4,4′-azobis (4-cyanovaleric acid) was added to THF 50
Then, 4.6 g of N-hydroxysuccinimide and 8.24 g of N, N'-dicyclohexylcarbodiimide were added thereto, followed by stirring at room temperature for 24 hours. afterwards,
The THF was distilled off, and the residue was dispersed in 500 ml of acetone to remove a precipitate. The acetone was distilled off to obtain a diester of 4,4′-azobis (4-cyanovaleric acid).

Then, 1.76 g of the above crystals was added to DMF35
Then, 0.74 g of dodecylamine was added thereto, followed by stirring overnight. The reaction solution was poured into 300 ml of water, and the deposited precipitate was filtered / washed with water, redissolved in dimethoxyethane, dried over magnesium sulfate, the solvent was distilled off, and the residue was washed / dried with ethyl acetate to obtain the diester. A product in which one ester of was replaced by dodecylamine was obtained.

Subsequently, 1.7 g of the dried product was dispersed in 20 ml of methanol, and 2 mol / L of NaO was added thereto.
H1.6 ml was added and the mixture was stirred at room temperature to hydrolyze the remaining ester to obtain the following target compound 1.

[0087]

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[Preparation Example 2 of Polymerization Initiator] In Preparation Example 1 of polymerization initiator, 2.72 g of a product obtained by substituting one of the diesters with dodecylamine was added to methanol 40.
Then, 0.87 g of sulfanilic acid was added thereto, and the mixture was stirred overnight. Then, 0.03 ml of a 0.5 mol / L aqueous sodium hydroxide solution was added thereto, and the following target compound 2 was added.
I got

[0089]

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[Preparation Example 3 of Polymerization Initiator] Preparation Example 1 of polymerization initiator, except that in Example 1 of polymerization initiator, 0.41 g of n-hexylamine was used instead of 0.74 g of dodecylamine. In the same manner as in the above, the following target compound 3 was obtained.

[0091]

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[Preparation Example 4 of Polymerization Initiator] Same as Preparation Example 2 of polymerization initiator except that in Preparation Example 2 of polymerization initiator, 1.08 g of stearylamine was used instead of 0.74 g of dodecylamine. The following target compound 4 was obtained.

[0093]

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[Preparation Example 5 of Polymerization Initiator] In Preparation Example 1 of polymerization initiator, tetracosylamine (tetracosylamine) was used instead of 0.74 g of dodecylamine.
e) Except that the amount was changed to 1.41 g, the following target compound 5 was obtained in the same manner as in Preparation Example 1 of the polymerization initiator.

[0095]

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[Preparation Example 6 of Polymerization Initiator] In Preparation Example 2 of polymerization initiator, 0.74 g of dodecylamine was replaced with 0.63 g of decylamine, and sulfanilic acid (sulfanilic acid) was used.
id) Instead of 0.87 g, 2-aminoethanesulfonic acid (2-aminoethanesulfonic acid)
cid) Except having changed to 0.63 g, the following target compound 6 was obtained in the same manner as in Preparation Example 2 of the polymerization initiator.

[0097]

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[Production Example 1 of Core Particles] 10 parts by mass of phenol 6 parts by mass of formaldehyde (about 40% of formaldehyde, about 10% of methanol, water is the rest) 58 parts by mass of magnetite (particle diameter 0.26 μm, specific resistance) 5.4 × 10 ¹² Ωcm) α-Fe ₂ O ₃ 32 parts by mass (particle size: 0.58 μm, specific resistance: 8.7 × 10 ⁹ Ωcm) 28% ammonia water as a basic catalyst, polymerization stabilization, Calcium fluoride and water were placed in a flask as an agent, and the temperature was raised to and maintained at 85 ° C. for 45 minutes with stirring and mixing, followed by reaction and curing for 3 hours. Thereafter, the mixture was cooled to 30 ° C., and after 10 times the amount of water was added, the supernatant was removed.
The precipitate was washed with water and air-dried. Then, this was reduced under reduced pressure (5
(mmHg or less) at 60 ° C. In addition, 200 ° C
For 1 hour to cure. This was classified using a multi-segment classifier, specifically, Elbow Jet Lab EJ-L-3 (manufactured by Nippon Steel Mining Co., Ltd.) to cut fine powder. The obtained carrier core 1 has a number average particle size of 28 μm and a size of 14 μm.
The cumulative distribution value of m (1/2 diameter) or less was 0.4 number%. When the specific resistance of the obtained carrier core particles 1 was measured, it was 1.2 × 10 ¹² Ω · cm.

[Production Example 2 of Core Particles] Fe ₂
O ₃ = 52 mol%, CuO = 26 mol%, ZnO = 22
The mixture was weighed so as to be mol% and mixed using a ball mill. After holding this at 900 ° C. for 1 hour and calcining,
Grinding was performed for 8 hours using a ball mill. An appropriate amount of a dispersant and a binder were added thereto, and the mixture was granulated and dried by a spray drier. This was sintered at 1240 ° C. for 4 hours.
Thereafter, the mixture was crushed and further classified to obtain carrier core particles 2. The carrier core 2 has a number average particle size of 42 μm,
The cumulative value of distribution below μm (1/2 diameter) is 12.1% by number.
Met. When the specific resistance of the obtained carrier core particles 2 was measured, it was 3.9 × 10 ⁸ Ω · cm.

[Production Example 3 of Core Particles] 14 parts by weight of styrene-butyl methacrylate copolymer (80/20) (weight average molecular weight: 32,000, number average molecular weight: 19000) 58 parts by weight of magnetite (particle diameter 0) .26 μm, specific resistance 5.4 × 10 ¹² Ωcm) α-Fe ₂ O ₃ 28 parts by mass (particle size 0.58 μm, specific resistance 8.7 × 10 ⁹ Ωcm) The above materials were sufficiently premixed with a Henschel mixer. After that, the mixture was melt-kneaded twice with a three-roll mill, cooled, and coarsely ground to a particle size of about 2 mm using a hammer mill. Next, the particle size is about 37μ with a fine pulverizer using an air jet method.
m. Further, the obtained finely pulverized product was put into a Mechanomill MM-10 (manufactured by Okada Seiko) and mechanically sphericalized.

The spheroidized finely pulverized particles were further classified to obtain a magnetic material-dispersed resin carrier core 3. The obtained carrier core 3 had a number average particle diameter of 35 μm and a distribution cumulative value of 倍 or less diameter was 11.5 number%. When the specific resistance of the obtained carrier core particles was measured, 7.2 × 10
It was ¹¹ Ω · cm.

[Production Example of Toner] 700 parts by mass of ion-exchanged water and 460 parts by mass of a 0.1 mol / L aqueous solution of Na ₃ PO ₄ were added to a four-necked flask equipped with a high-speed stirrer TK-Homomixer. Then, the rotation speed was adjusted to 12000 rpm, and the mixture was heated to 65 ° C. 80 parts by mass of a 1.0 mol / liter-CaCl ₂ aqueous solution was gradually added thereto to prepare an aqueous dispersion medium containing a minute hardly water-soluble dispersion stabilizer Ca ₃ (PO ₄ ) ₂ .

Styrene monomer 165 parts by mass n-butyl acrylate monomer 35 parts by mass Cyan colorant (CI Pigment Blue 15: 3) 14 parts by mass Negative charge control agent (metal dialkylsalicylate) Compound) 2 parts by mass ・ Ester wax 30 parts by mass After dispersing the above mixture for 3 hours using an attritor,
A polymerizable monomer composition to which 10 parts by mass of 2,2′-azobis (2,4-dimethylvaleronitrile) as a polymerization initiator was added was charged into an aqueous dispersion medium, and the number of rotations was 12,000 r.
Granulation was carried out for 15 minutes while maintaining pm. After that, change the stirrer from the high-speed stirrer to the propeller stirring blade,
The polymerization was continued for 10 hours at a rotation speed of 250 rpm. After the polymerization was completed, the slurry was cooled, and diluted hydrochloric acid was added to remove the dispersion stabilizer. This is washed and dried to have a weight average particle size of 5.
Toner particles having a size of 6 μm and a coefficient of variation in the number distribution of 12% were obtained.

With respect to 100 parts by mass of the toner particles, B
2 parts by mass of hydrophobic silica having a specific surface area of 120 m ² / g is obtained by subjecting the surface of a silica matrix having a specific surface area of 200 m ² / g by the ET method to a hydrophobic treatment with a silane coupling agent and silicone oil. Thus, a toner was obtained.

<Example 1> A polymerization vessel equipped with a mechanical stirrer and a nitrogen bubbling inlet tube was charged with: 500 parts by weight of water 3 parts by weight of the compound 13 obtained in Production Example 1 of a polymerization initiator To this, 1500 parts by mass of the particles obtained in Production Example 1 of core particles were sufficiently dispersed. While maintaining the inside of the system at 20 ° C., nitrogen was bubbled into the solution until the amount of dissolved oxygen in the system became 0.1 mg / liter. While heating the polymerization vessel at a heating rate of 5 ° C./min, a solution composed of 10 parts by mass of styrene, 2 parts by mass of 2-ethylhexyl methacrylate, and 1.2 parts by mass of divinylbenzene was added dropwise over 2 hours. 80 polymerization containers
C. and polymerized for 10 hours with stirring. Nitrogen bubbling was continued during the polymerization.

After the polymerization was completed, the content of fine powder in the polymerization reaction solution was measured to be 2.1 particles / μl, indicating that the core particles were efficiently coated.

The dispersion was washed and dried to obtain a coated carrier. When the specific resistance of the obtained carrier was measured, it was 4.8 × 10 ¹³ Ω · cm.

96 parts by mass of the obtained carrier and 4 parts by mass of the toner obtained in the toner production example were mixed to prepare a two-component developer.

Using this two-component developer, the following evaluation was performed using a modified full-color laser copying machine CLC-500 manufactured by Canon. The same evaluation was performed after continuous printing of 30,000 sheets. Table 3 shows the results.

(Method of Measuring Fine Powder Content after Polymerization) The fine powder content is measured using a flow particle image analyzer FPIA-1000 manufactured by Toa Medical Electronics. In the present invention, after the polymerization of the vinyl polymerizable monomer is completed, 1 ml of the supernatant of the reaction solution in which only the coat carrier has been precipitated is added to 150 ml of a 0.2% by mass aqueous solution of sodium dodecylbenzenesulfonate from which impure solids and the like have been removed in advance. This is subjected to a dispersion treatment for 3 minutes by an ultrasonic disperser, and measured by the above-mentioned device.

(Evaluation of Carrier Surface State) Evaluation was performed based on the following evaluation criteria by observing with a scanning electron microscope S-4700 (manufactured by Hitachi, Ltd.) at an acceleration voltage of 1 kV.

Evaluation Criteria A: For particles of 95% by number or more, there is no difference in surface state between the particles. B: For particles of 85% by number or more and less than 95% by number, there is no difference in surface state between the particles. C: Regarding particles of 70% by number or more and less than 85% by number, there is no difference in surface state between the particles. D: The surface condition between the particles varies. E: The exposure of the core particle surface is remarkable.

(Measurement of Amount of Friction Charge of Toner) 4 parts by mass of the toner and 96 parts by mass of the carrier are mixed, and mixed by a Turbula mixer for 180 seconds. This mixed powder (developer)
Is placed in a metal container equipped with a conductive screen with an aperture of 20 μm (635 mesh) at the bottom, and suctioned with a suction machine. Friction charging is performed based on the difference in mass before and after suction and the potential accumulated in the condenser connected to the container. Find the quantity. At this time, the suction pressure is set to 250 mmHg. With this method, the triboelectric charge amount is calculated using the following equation.

[0114]

(Equation 1) (Where W1 is the mass before suction, W2 is the mass after suction, C is the capacity of the capacitor, and V is the potential stored in the capacitor.)

(Evaluation of Image) 4 parts by mass of toner, carrier 9
6 parts by mass, and mix with a turbula mixer.
Mix for 0 seconds. Using this two-component developer, an image was formed using a modified full-color laser copying machine CLC-500 manufactured by Canon. A mat was formed so that the surface roughness of the developer carrier of the developing device was Rz = 10. Further, in order to precisely evaluate the reproducibility of halftone, the normal laser spot diameter was reduced by 20%.

As a method of evaluating the reproducibility of the halftone formed by the minimal spot, the reproducibility of the toner with respect to the minimal spot is determined by multi-value recording by pulse width modulation (PWM) of the laser in one pixel. By observing the surface with a microscope, evaluation was made based on the following evaluation criteria.

Evaluation Criteria A: No disturbance of dots and very good reproduction of minute dots. B: No scattering and slight variation in dot shape. Good C: Scattering and variation in dot shape. No problem D: Scattering, variation in dot shape is remarkable E: Not developed where dots should be, or scattering is severe

(Sampling method for measuring various physical properties of carrier after continuous printing)
The solution is measured to have a concentration of 10% by mass with respect to the aqueous solution of sodium dodecylbenzenesulfonate by mass%, and after sufficiently stirring, ultrasonic irradiation is performed for 3 minutes. Thereafter, the magnet is approached from the outside of the container to adsorb only the carrier, and the decantation is repeated five times to wash, dry, and used for various evaluations.

<Examples 2 to 9> Coated carriers were obtained and evaluated in the same manner as in Example 1 except that the formulations shown in Table 2 were used. Table 3 shows the results.

Comparative Example 1 A polymerization vessel equipped with a mechanical stirrer and a nitrogen bubbling inlet tube was charged with: 500 parts by weight of water; 3 parts by weight of the compound obtained in Production Example 1 of a polymerization initiator. While maintaining the inside of the system at 20 ° C., nitrogen was bubbled through the solution until the amount of dissolved oxygen in the system became 0.1 mg / liter. While heating the polymerization vessel at a rate of temperature increase of 5 ° C./min, a solution composed of 10 parts by mass of styrene, 2 parts by mass of 2-ethylhexyl methacrylate, and 1.2 parts by mass of divinylbenzene was added dropwise over 2 hours. 80 polymerization containers
C. and polymerized for 10 hours with stirring. Nitrogen bubbling was continued during the polymerization. The produced resin 1 was collected by washing and drying.

A mixture consisting of 5 parts by mass of the resin 1 and 100 parts by mass of toluene was prepared. Since the resin 1 was not sufficiently dissolved, it was dispersed to form a coating solution.

The above coating solution was poured into 500 parts by mass of the core particles obtained in Production Example 1 of the core particles while applying a shearing stress by stirring, and the solvent was volatilized by heating to perform a coating treatment on the core particles. . This was crushed and classified with a sieve having openings of 82 μm (200 mesh) to obtain a coated carrier.

Using this, evaluation was performed in the same manner as in Example 1.

<Comparative Example 2> Resin 2 was obtained in the same manner as in Comparative Example 1 except that divinylbenzene was not added.

A mixture comprising 5 parts by mass of the resin 2 and 100 parts by mass of toluene was prepared, and a coating solution in which the resin 2 was dissolved was obtained.

When the above coating solution was poured while applying shear stress by stirring to 500 parts by mass of the core particles obtained in Production Example 3 of core particles, the core particles were adhered and integrated to obtain a coated carrier. Did not.

Comparative Example 3 The coating liquid used in Comparative Example 2 was poured into 500 parts by mass of the core particles obtained in Production Example 2 of core particles while applying shear stress by stirring, and the solvent was volatilized by heating. The core particles were coated. This is crushed, and the opening 82
The coated carrier was obtained by classification with a sieve of 200 μm (μm).

Using this, evaluation was performed in the same manner as in Example 1.

<Comparative Example 4> A mixture consisting of 5 parts by mass of the resin 15 obtained in Comparative Example 1 and 500 parts by mass of the core particles obtained in Production Example 1 of core particles was mixed with a hybridization system to obtain a mixture of 3 parts.
2,000 rpm for 20 minutes to fix mechanically. Classification was performed using a sieve having openings of 82 μm (200 mesh) to obtain a coated carrier.

Using this, evaluation was performed in the same manner as in Example 1.

[0131]

[Table 1]

[0132]

[Table 2]

[0133]

[Table 3]

[0134]

According to the present invention, it is possible to widely cope with the formulation of the coating agent satisfying the desired characteristics, and the difference in the coating amount and the coating state between the carrier particles is small and uniform regardless of the type of the core particles. Can be coated efficiently.

[Brief description of the drawings]

FIG. 1 is a schematic view of an apparatus for measuring the specific resistance of a carrier, carrier core particles, and a metal oxide.

Claims (18)

[Claims] 1. A method for producing a coated carrier having at least core particles and a coating resin, comprising: forming a dispersion in which the core particles are dispersed in a polymerization medium in which the coating resin is not dissolved;
A method for producing a coated carrier, comprising a step of polymerizing a vinyl polymerizable monomer constituting the coated resin to form the coated resin layer on the surface of the core particles. 2. In the step of dispersing the core particles,
The method for producing a coated carrier according to claim 1, wherein a polymerization initiator having a hydrophilic site, a hydrophobic site, and a reactive site in one molecule is used. 3. The method according to claim 2, wherein the polymerization initiator is a compound represented by the following formula (1). R ¹ —X—Z—Y—R ² (1) (wherein, R ¹ is a hydrophobic group, R ² is a hydrophilic group,
Z is a reactive group, and X and Y are each the aforementioned R ¹
Or a unit for bonding R ² and Z. ) 4. The hydrophobic part of the polymerization initiator is selected from an aliphatic hydrocarbon group having 5 to 60 carbon atoms, an aromatic hydrocarbon group having 6 to 60 carbon atoms, a heterocyclic group and a polysiloxane residue. The method for producing a coated carrier according to claim 2, wherein the method further comprises at least one group. 5. The polymerization initiator according to claim 1, wherein the hydrophilic portion is a polysaccharide group, a hydroxyl group, a sulfate group, a sulfate group, a sulfonic group, a sulfonic group having a salt structure, a carboxyl group, a carboxylate, or a phosphate. The coated carrier according to any one of claims 2 to 4, comprising at least one group selected from a group, a phosphate, a heterocyclic group, a heterocyclic salt, an amino group, and an ammonium salt. Manufacturing method. 6. The reactive site contained in the polymerization initiator is at least one group selected from an azo group, a peroxide group, a diketo group and a persulfate group. 6. The method for producing a coated carrier according to any one of claims 1 to 5. 7. In the above formula (1), R ¹ is selected from an aliphatic hydrocarbon group having 5 to 60 carbon atoms, an aromatic hydrocarbon group having 6 to 60 carbon atoms, a heterocyclic group, and a polysiloxane residue. The method for producing a coated carrier according to any one of claims 3 to 6, wherein the group is at least one selected group. 8. In the above formula (1), R ² represents a polysaccharide group, a hydroxyl group, a sulfate group, a sulfate, a sulfonic acid group, a sulfonic acid group having a salt structure, a carboxyl group, a carboxylate, phosphoric acid Claims: It is an aliphatic or aromatic hydrocarbon group having at least one group selected from an ester group, a phosphate, a heterocyclic group, a heterocyclic salt, an amino group, and an ammonium salt as a substituent. Item 8. The method for producing a coated carrier according to any one of Items 3 to 7. 9. The method according to claim 8, wherein the aromatic hydrocarbon group of R ² has 1 to 20 carbon atoms. 10. The method according to claim 8, wherein the aromatic hydrocarbon group of R ² has 6 to 20 carbon atoms. 11. In the formula (1), Z is an azo group,
The method for producing a coated carrier according to any one of claims 3 to 10, wherein the method is at least one group selected from a peroxide group and a diketo group. 12. In the formula (1), Z is a polyvalent group, and X and Y are the same or different and are selected from a carbon-carbon bond, an ester bond, an amide bond, an ether bond, a urethane bond and a urea bond. The method for producing a coated carrier according to any one of claims 3 to 10, wherein the coated carrier has at least one kind of bond, and one of X and Y has an electron-withdrawing group. 13. The method according to claim 3, wherein the compound represented by the formula (1) is the following formula (2). ^{R 1a -A 1 -R 3 -N =} N-R 4 -A 2 -R 2a (2) ( wherein, R ^1a is C1-20 long chain aliphatic hydrocarbon group or a C 6 to 30 carbon atoms 6 to 1 carbon atoms having an alkyl group
An aryl group of 2 (excluding the alkyl moiety), R ^2a
Is a carboxyl group, a carboxylic acid group, a sulfate group, a sulfate group, a sulfonic group, a sulfonic group having a salt structure, and an aliphatic or aromatic group having at least one of these groups as a substituent and having 1 to 20 carbon atoms. R ³ and R ⁴ are the same or different and are alkylene groups having an electron-withdrawing group at a carbon atom adjacent to the azo group, and A ¹ is nothing or A ² represents at least one bond selected from an ester bond, an amide bond, a urethane bond and an ether bond, and A ² represents at least one selected from nothing or an ester bond, an amide bond, a urethane bond and an ether bond. Shows species binding. ) 14. A compound represented by the formula (2):
R ^1a is a long-chain aliphatic hydrocarbon group having 10 to 22 carbon atoms, or a phenyl group having an alkyl group having 1 to 18 carbon atoms as a substituent, and R ^2a is a carboxyl group, a carboxylic acid group,
Group consisting of a sulfate group, a sulfate group, a sulfonic group, a sulfonic group having a salt structure, and an aliphatic or aromatic hydrocarbon group having 1 to 20 carbon atoms having at least one of these groups as a substituent. Group selected from
R ³ and R ⁴ are the same or different and are an alkylene group having 2 to 6 carbon atoms having a cyano group at a carbon atom adjacent to the azo group, and A ¹ is a group having nothing or an ester bond and an amide bond. showed binding to be selected, a ² the method for manufacturing a coated carrier according to claim 13, characterized in that show binding that is selected from nothing or no or ester bond and an amide bond. 15. The method for producing a coated carrier according to claim 2, wherein the amount of the polymerization initiator is in the range of 0.001 to 10% by mass based on the core particles. . 16. The method for producing a coated carrier according to claim 1, wherein the vinyl polymerizable monomer contains a crosslinking agent. 17. The method according to claim 16, wherein the content of the crosslinking agent is in the range of 0.01 to 30% by mass based on the total amount of the vinyl polymerizable monomer. 18. The method according to claim 1, further comprising, before the step of polymerizing the vinyl polymerizable monomer, a step of adjusting the amount of dissolved oxygen in the system to 2 vol% or less. Manufacturing method of coated carrier.