JP2012128141A - Production method of toner and toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method of toner, which gives a toner excellent in productivity and excellent in heat-resistant storage property, low-temperature fixability and preventing property against toner scattering.SOLUTION: The production method aims to produce a core-shell toner having a core layer containing a first resin and a colorant and a shell layer on the core layer. The production method for the toner includes: a shell-forming step of mixing a dispersion liquid (1) containing core particles containing the first resin and the colorant with a dispersion liquid (2) containing particles for the shell layer containing a second resin having vinyltriaryl imidazole, so as to coat the core particle with a layer (A) containing the second resin; and a crosslinking step of treating the layer (A) with an oxidizing agent solution containing an oxidizing agent to crosslink the second resin.

Description

  The present invention relates to a method for producing toner used in an image forming method using an electrophotographic image forming apparatus.

  In recent years, from the viewpoint of global warming prevention, energy saving has been studied in various fields, and efforts have been made to use low energy, such as power saving during standby, in information devices such as image forming apparatuses. On the other hand, studies have been made to lower the fixing temperature in the fixing process that consumes the most energy.

  In order to realize such a decrease in the fixing temperature, for example, Patent Document 1 discloses that a polymer containing a carboxylic acid component and a polyvalent metal compound are combined as toner used in an electrophotographic image forming apparatus. Toners containing crosslinked resins are disclosed.

  According to such a toner, since the melt viscosity of the resin is lowered by cleaving the bond related to the crosslinking by heat at the time of heat fixing, low temperature fixability can be obtained while heat resistant storage stability at the time of storage can be obtained.

  In general, a toner having a basic structure is originally formed of a resin having a high glass transition point in order to obtain heat-resistant storage property, but there is a problem that the fixing temperature must be high. That is, it is difficult to satisfy both the heat-resistant storage property and the low-temperature fixability because they are in a trade-off relationship.

  Even using such a resin as described above, the fixing temperature is required to be at least about 150 ° C., and there is a problem that sufficient low-temperature fixing property may not be obtained.

Japanese Patent Publication No. 8-3665

  An object of the present invention is to provide a toner production method that gives a toner that is excellent in productivity, excellent in heat-resistant storage and low-temperature fixability, and excellent in toner scattering prevention.

  The above-described problems of the present invention are solved by the following means.

  1. A toner production method for producing a core-shell type toner having a core layer containing a first resin and a colorant and having a shell layer on the core layer, the method comprising the first resin and the colorant A dispersion (1) containing core particles to be dispersed, and a dispersion (2) containing particles for a shell layer containing a second resin having a triarylimidazole group represented by the following general formula (1) A shelling step of mixing and covering the core particles with the layer A containing the second resin, and treating the layer A with an oxidizing agent solution containing an oxidizing agent to crosslink the second resin A toner production method comprising a crosslinking step.

[Wherein R ¹ represents a hydrogen atom or a chlorine atom. R ² and R ³ represent a hydrogen atom, a chlorine atom or a methoxy group. ]
2. A method for producing a toner, wherein the second resin is a resin obtained by polymerization using a polymerizable monomer represented by the following general formula (2).

[Wherein R ¹ represents a hydrogen atom or a chlorine atom. R ² and R ³ represent a hydrogen atom, a chlorine atom or a methoxy group. R ⁴ represents a hydrogen atom or a methyl group. L represents a single bond or a divalent linking group. ]
3. A toner produced by the method for producing a toner according to 1 or 2, comprising a core layer containing the first resin and the colorant, and the general formula (1) is formed on the core layer. A toner comprising a shell layer containing a second resin having a triarylimidazole group represented, wherein the surface of the shell layer has a crosslinked structure represented by the following general formula (3).

[Wherein R ¹ represents a hydrogen atom or a chlorine atom. R ² and R ³ represent a hydrogen atom, a chlorine atom or a methoxy group. R ⁴ represents a hydrogen atom or a methyl group. L represents a single bond or a divalent linking group. ]

  By the above means of the present invention, there is provided a toner production method that provides a toner having excellent productivity, heat-resistant storage stability, at the same time, sufficient low-temperature fixability, high particle strength, and excellent toner scattering prevention properties. it can.

  The present invention relates to a toner production method for producing a core-shell type toner having a core layer containing a first resin and a colorant and having a shell layer on the core layer, the method comprising: Dispersion (1) containing core particles containing a colorant, and dispersion containing shell layer particles containing a second resin having a triarylimidazole group represented by the general formula (1) 2) and covering the core particles with the layer A containing the second resin, and treating the layer A with an oxidizing agent solution containing an oxidizing agent, It has the crosslinking process which bridge | crosslinks resin.

  In the present invention, in particular, the resin having the triarylimidazole group is used for the shell layer, and after providing the shell layer on the core layer, the resin is cross-linked using an oxidizing agent. Thus, it is possible to provide a method for producing a toner that has a good heat-resistant storage property and at the same time has sufficient low-temperature fixability, and has a high particle strength and excellent toner scattering prevention property.

  The production method of the present invention includes a dispersion (1) containing core particles containing a first resin and the colorant, and a second resin having a triarylimidazole group represented by the general formula (1). And the dispersion liquid (2) containing the particles for the shell layer containing, and a shelling step for covering the core particles with the layer A containing the second resin, and the oxidation containing the oxidizing agent for the layer A And a crosslinking step of treating with the agent solution and crosslinking the second resin.

(Shelling process)
In the shelling step, a dispersion (1) containing core particles containing the first resin and the colorant, and a second resin having a triarylimidazole group represented by the general formula (1) are contained. This is a step of mixing the dispersion (2) containing the shell layer particles to be covered and covering the core layer with the layer A containing the second resin.

  The core layer is composed of core particles containing a first resin and a colorant.

  The method for producing the core particles is not limited, but a first resin dispersion containing the first resin particles is produced, and a colorant dispersion containing the colorant particles is produced. From the viewpoint of productivity, it is preferable to produce core particles by mixing the first resin particles and the colorant particles.

  Other methods for producing the core particles include, for example, suspension polymerization in which monomer droplets containing a colorant are polymerized to form a core particle dispersion, or oil droplets in which a resin and a colorant are dissolved or dispersed in a solvent. For example, a solvent desolubilization method in which the solvent in the oil droplets is removed to form a core particle dispersion.

  Layer A is formed by mixing the dispersion liquid (1) containing the core particles and the dispersion liquid (2) containing the shell layer particles containing the second resin.

  Below, preparation of a 1st resin dispersion liquid, a colorant dispersion liquid, a dispersion liquid (2), and the formation method of the layer A (shell layer) are demonstrated.

(Preparation of first resin dispersion)
For example, if the first resin uses a radical polymerizable monomer such as styrene acryl, the step of preparing the first resin dispersion is radical initiation on the polymerizable monomer that should form the thermoplastic resin. Dissolve or disperse the agent and chain transfer agent, and if necessary, dissolve or disperse the toner particle constituent materials such as the release agent and charge control agent to prepare a polymerizable monomer solution, which is used as a surface active agent. A step of obtaining the first resin dispersion liquid by adding it into an aqueous medium using an agent, etc., and performing a polymerization reaction while mixing and stirring can be mentioned.

  Further, if the first resin is a resin such as polyester, the polyester resin is dissolved in a solvent such as ethyl acetate, and emulsified and dispersed in an aqueous medium using a surfactant. There is a step of performing a solvent removal treatment to obtain a first resin dispersion.

  However, it is not restricted to these methods.

  The first resin particles in the dispersion prepared in these steps preferably have a volume-based median diameter in the range of 80 to 500 nm.

  Here, the “aqueous medium” refers to a medium composed of 50 to 100% by mass of water and 0 to 50% by mass of a water-soluble organic solvent.

  Examples of the water-soluble organic solvent include methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, and tetrahydrofuran, and alcohol-based organic solvents that do not dissolve the resulting resin are preferable.

  Examples of the first resin include thermoplastic resins such as polyester resins, styrene resins, (meth) acrylic resins, vinyl polymers such as styrene acrylic resins, olefin resins, polyamide resins, polycarbonate resins, and polyresins. Examples include ether resins, polyvinyl acetate resins, polysulfone resins, polyurethane resins, and the like. Preference is given to polyester resins and styrene acrylic resins.

  The polyester resin can be synthesized by polycondensation of a polyhydric alcohol and a polyvalent carboxylic acid.

  As the polyhydric alcohol, if it is non-radically polymerizable, for example, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1, 7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-dodecanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1, Aliphatic diols such as 14-tetradecanediol, 1,18-octadecanediol, 1,20-eicosanediol; bisphenols such as bisphenol A and bisphenol F; and bisphenols such as these ethylene oxide adducts and propylene oxide adducts Of alkylene oxide adducts It can be mentioned, and as the trivalent or higher-valent alcohols include glycerin, trimethylolpropane, pentaerythritol, sorbitol and the like.

  Further, those having radical polymerizability include, for example, 2-butene-1,4-diol, 3-butene-1,6-diol, 4-butene-1,8-diol, and 9-octadecene-7,12 diol. And those having a radically polymerizable unsaturated double bond such as 2-butyne-1,4 diol and 3-butyne-1,4 diol. These can be used individually by 1 type or in combination of 2 or more types. Examples of the polyvalent carboxylic acid include non-radical polymerizable ones such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelic acid, sebacic acid, 1,9-nonane. Dicarboxylic acid, 1,10-decanedicarboxylic acid, 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,16-hexadecanedicarboxylic acid Acids, aliphatic dicarboxylic acids such as 1,18-octadecanedicarboxylic acid; lower alkyl esters and acid anhydrides thereof; phthalic acid, terephthalic acid, isophthalic acid, orthophthalic acid, t-butylisophthalic acid, 2,6-naphthalenedicarboxylic acid Acids, aromatic dicarboxylic acids such as 4,4′-biphenyldicarboxylic acid; Lit acids, such as trihydric or higher polycarboxylic acids such as pyromellitic acid.

  In addition, unsaturated fatty acids such as maleic acid, fumaric acid, itaconic acid, citraconic acid, glutaconic acid, isododecenyl succinic acid, n-dodecenyl succinic acid, n-octenyl succinic acid, etc., as long as they have radical polymerizability Dicarboxylic acids; and acid anhydrides or acid chlorides thereof; maleic acid, fumaric acid and itaconic acid are preferably used because they exhibit particularly excellent radical polymerizability.

  These can be used individually by 1 type or in combination of 2 or more types.

  As a vinyl polymer such as styrene acrylic resin, radically polymerizable monomers for obtaining this are styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn -Styrene or styrene derivatives such as dodecyl styrene; methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, Stearyl methacrylate, Methacrylic acid ester derivatives such as lauryl tacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate; methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, acrylic Acrylic acid ester derivatives such as isobutyl acid, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, and phenyl acrylate; olefins such as ethylene, propylene, and isobutylene; vinyl fluoride, vinylidene fluoride Vinyl fluorides such as vinyl propionate, vinyl acetate, vinyl benzoate, and other vinyl esters; vinyl methyl ether, vinyl ethyl ether, and other vinyl ethers; Vinyl ketones such as til ketone, vinyl ethyl ketone and vinyl hexyl ketone; N-vinyl compounds such as N-vinyl carbazole, N-vinyl indole and N-vinyl pyrrolidone; Vinyl compounds such as vinyl naphthalene and vinyl pyridine; acrylonitrile, methacrylate Examples thereof include vinyl monomers such as acrylic acid or methacrylic acid derivatives such as nitrile and acrylamide. These vinyl monomers can be used alone or in combination of two or more.

  Moreover, it is preferable to use what has an ionic dissociation group as a radically polymerizable monomer. The polymerizable monomer having an ionic dissociation group has, for example, a substituent such as a carboxyl group, a sulfonic acid group, and a phosphoric acid group as a constituent group, and specifically includes acrylic acid, methacrylic acid, maleic acid. Acid, itaconic acid, cinnamic acid, fumaric acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester, styrene sulfonic acid, allyl sulfosuccinic acid, 2-acrylamido-2-methylpropane sulfonic acid, acid phosphooxyethyl methacrylate Etc.

  In order to stably disperse the particles in the aqueous medium, a surfactant may be added to the aqueous medium. Examples of such a surfactant include various conventionally known anionic surfactants and cationic systems. Surfactants, nonionic surfactants, and the like can be used. This also applies to the subsequent preparation of the dispersion.

  Examples of the anionic surfactant include higher fatty acid salts such as sodium oleate; alkyl aryl sulfonates such as sodium dodecylbenzene sulfonate; alkyl sulfate salts such as sodium lauryl sulfate; polyethoxyethylene lauryl ether sodium sulfate Polyoxyethylene alkyl ether sulfate salts of polyoxyethylene alkylaryl ether sulfate salts such as sodium polyoxyethylene nonylphenyl ether sulfate; sodium monooctyl sulfosuccinate, sodium dioctyl sulfosuccinate, sodium polyoxyethylene lauryl sulfosuccinate, etc. Examples thereof include alkyl sulfosuccinic acid ester salts and derivatives thereof.

  Examples of the cationic surfactant include aliphatic amine salts, aliphatic quaternary ammonium salts, benzalkonium salts, benzethonium chloride, pyridinium salts, and imidazolinium salts.

  Furthermore, examples of nonionic surfactants include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether and polyoxyethylene stearyl ether, polyoxyethylene alkyl phenyl ethers such as polyoxyethylene nonylphenyl ether, and sorbitan mono Sorbitan higher fatty acid esters such as laurate, sorbitan monostearate, sorbitan trioleate; polyoxyethylene sorbitan higher fatty acid esters such as polyoxyethylene sorbitan monolaurate; polyoxyethylene monolaurate, polyoxyethylene monostearate Polyoxyethylene higher fatty acid esters such as glycerin higher fatty acid esters such as oleic acid monoglyceride and stearic acid monoglyceride Ethers; polyoxyethylene - polyoxypropylene - and the like block copolymer.

  The polymerization initiator is a water-soluble polymerization initiator having a 10-hour half-life temperature of less than 10-hour half-life temperature (A), preferably less than (A-10 ° C.) according to the radical generator used. As long as there is something, an appropriate thing can be used.

  Specific examples of the polymerization initiator include persulfates (potassium persulfate, ammonium persulfate, etc.), azo compounds (4,4′-azobis-4-cyanovaleric acid and its salts, 2,2′-azobis (2- Amidinopropane) salts), organic peroxides and the like.

  Generally used chain transfer agents can be used for the purpose of adjusting the molecular weight of the thermoplastic resin.

  The chain transfer agent is not particularly limited, and examples thereof include mercaptans such as 2-chloroethanol, octyl mercaptan, dodecyl mercaptan, and t-dodecyl mercaptan, and styrene dimers.

  After mixing the first resin dispersion obtained as described above and the colorant dispersion described below, the pH of the mixture can be adjusted and aggregated to form core particles. At this time, it is effective to use a flocculant.

  As the flocculant to be used, a surfactant having a reverse polarity to the surfactant used for the dispersant, an inorganic metal salt, and a metal complex having a valence of 2 or more can be preferably used. In particular, the use of a metal complex is particularly preferable because the amount of the surfactant used can be reduced and the charging characteristics are improved.

  Examples of the inorganic metal salt include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate, and polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. Examples thereof include inorganic metal salt polymers.

(Preparation of colorant dispersion)
As a process for preparing a colorant dispersion, a colorant particle dispersion is prepared by adding a colorant to an aqueous medium and applying mechanical energy thereto to disperse the colorant particles in the aqueous medium. Is done.

  The disperser for dispersing oil droplets by mechanical energy is not particularly limited, and a stirring device “CLEAMIX” (manufactured by M Technique Co., Ltd.) equipped with a rotor that rotates at high speed, an ultrasonic disperser, Examples thereof include a mechanical homogenizer, a manton gourin, and a pressure homogenizer.

  The colorant particles in the dispersion prepared in the colorant dispersion preparation step preferably have a volume-based median diameter in the range of 20 to 1,000 nm, more preferably 20 to 140 nm, and particularly preferably 30. ~ 100 nm.

  The method for controlling the volume-based median diameter of the colorant particles to 20 to 1,000 nm can be controlled, for example, by adjusting the magnitude of the mechanical energy described above.

  As the colorant, various organic or inorganic pigments as exemplified below can be used.

  That is, as the colorant for black toner, carbon black, magnetic material, iron / titanium composite oxide black and the like can be used, and as carbon black, channel black, furnace black, acetylene black, thermal black, lamp black, etc. Can be used. Moreover, ferrite, magnetite, etc. can be used as the magnetic material.

  Examples of yellow colorants for yellow toner include C.I. I. Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, etc., and C.I. I. Pigment Yellow 14, 17, 74, 93, 94, 138, 155, 180, 185, etc. can be used, and mixtures thereof can also be used.

  As a magenta colorant for magenta toner, C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 122, etc. I. Pigment Red 5, 48: 1, 53: 1, 57: 1, 122, 139, 144, 149, 166, 177, 178, 222, etc. can be used. Mixtures can also be used.

  As a cyan colorant for cyan toner, C.I. I. Solvent Blue 25, C.I. I. Solvent Blue 36, C.I. I. Solvent Blue 60, C.I. I. Solvent Blue 70, C.I. I. Solvent Blue 93, C.I. I. Solvent Blue 95 and the like, C.I. I. Pigment Blue 1, 7, 15, 60, 62, 66, 76, etc. can be used.

  These pigments can be used alone or in combination of two or more.

  The content ratio of the colorant is preferably 0.5 to 20% by mass in the toner particles, and more preferably 2 to 10% by mass.

(Preparation of dispersion (2))
The dispersion liquid (2) is a dispersion liquid in which particles for a shell layer containing a second resin having a triarylimidazole group represented by the general formula (1) described below are dispersed.

(Second resin having a triarylimidazole group represented by the general formula (1))
In general formula (1), R ¹ is a hydrogen atom or a chlorine atom, preferably a hydrogen atom. In the general formula (1), when R ¹ is a chlorine atom, the group R ¹ is preferably bonded to the para position with respect to the imidazole ring.

When the group R ¹ consisting of a chlorine atom is bonded to the para position with respect to the imidazole ring, it is easy to form a cross-linking bond between the imidazole rings described later.

In the general formula (1), R ² and R ³ are a hydrogen atom, a chlorine atom or a methoxy group, preferably a hydrogen atom.

When R ² and R ³ in the triarylimidazole group represented by the general formula (1) are chlorine atoms, R ² and R ³ are in any of the ortho, meta, and para positions with respect to the imidazole ring. It may be combined.

When R ² and R ³ are methoxy groups, it is preferable that R ² and R ³ are bonded to the ortho position with respect to the imidazole ring.

R ² and R ³ are preferably the same from the viewpoint of productivity.

  The second resin having a triarylimidazole group represented by the general formula (1) can be obtained by a polymerization reaction using a polymerizable monomer having a triarylimidazole group represented by the general formula (1). it can.

  The polymerization reaction may be performed using only the monomer, or may be performed together with other comonomer.

  The polymerizable monomer can be used without particular limitation as long as it is a monomer used for radical polymerization, condensation polymerization, and the like, but the polymerizable monomer represented by the general formula (2) is used. I prefer that.

In General formula (2), L represents a single bond or a bivalent coupling group. R ^{1 to R 3,} from the ^{R 1} and ^{R 3} in the general formula (1) are each synonymous. That is, one of the groups bonded to L in the general formula (2) is a group represented by the general formula (1). R ⁴ represents a hydrogen atom or a methyl group.

  In the general formula (2), the imidazole ring in the triarylimidazole group is bonded to the meta position with respect to the group L with respect to the benzene ring to be bonded continuously to the group L in the triarylimidazole group. Is preferred.

The polymerizable triarylimidazole compound in which the imidazole ring is bonded to the meta position with respect to the group L ^{1 with} respect to the benzene ring to be bonded continuously to the group L in the triarylimidazole group is a cross-linking bond between the imidazole rings. Easy to form.

  Examples of the divalent linking group represented by L include —C (═O) —NH—, —C (═O) O—, —NH (C═O) NH— and —NH—C (═O ) O- and the like.

  As a polymerizable monomer represented by General formula (2), the compound represented by the following exemplary compounds 1-8 can be illustrated, for example.

  The second resin according to the present invention can be obtained by a polymerization reaction using the polymerizable monomer as described above, and is a copolymerizable monomer copolymerizable with the polymerizable monomer. Those copolymerized are preferably used.

  Examples of the monomer for copolymerization include (meth) acrylic acid, (meth) acrylic acid ester, and styrene.

  The copolymerization ratio of the polymerizable monomer (polymerizable triarylimidazole compound) and the monomer for copolymerization is 1:99 to 30: in a molar ratio of polymerizable triarylimidazole compound: monomer for copolymerization. 70 is preferable.

  In the present invention, the second resin is used for forming the shell layer. In order to form the shell layer, as described later, a dispersion liquid (2) containing particles for the shell layer containing the second resin is dispersed. ) Is used.

  In order to obtain this dispersion, a method in which a polymerization reaction is carried out in an aqueous medium is preferred, and so-called suspension polymerization method, emulsion polymerization method, emulsion association method and the like can be used.

  The shell layer containing the second resin may contain a charge control agent, and the charge control agent is a substance that can give positive or negative charge by frictional charging and is colorless. Any known positively chargeable charge control agent and negatively chargeable charge control agent can be used.

  The content ratio of the charge control agent in the toner is preferably 0.01 to 30 parts by mass, more preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the binder resin.

  Examples of the method for incorporating the charge control agent into the toner include the same methods as those described above for incorporating the release agent.

  Specifically, as the positive charge control agent, for example, a nigrosine dye such as “Nigrosine Base EX” (manufactured by Orient Chemical Industries), “quaternary ammonium salt P-51” (manufactured by Orient Chemical Industries), “ Quaternary ammonium salts such as “Copy Charge PX VP435” (manufactured by Hoechst Japan), alkoxylated amines, alkylamides, molybdate chelate pigments, and imidazole compounds such as “PLZ1001” (manufactured by Shikoku Kasei Kogyo Co., Ltd.) Examples of the negative charge control agent include “Bontron S-22” (manufactured by Orient Chemical Industries), “Bontron S-34” (manufactured by Orient Chemical Industries), and “Bontron E-81” (Orient Chemical Industries). , "Bontron E-84" (manufactured by Orient Chemical Co., Ltd.), "Spiron Black TRH" Metal complexes such as (Hodogaya Chemical Industries, Ltd.), thioindigo pigments, quaternary ammonium salts such as “Copy Charge NX VP434” (Hoechst Japan), “Bontron E-89” (Orient Chemical Industries) And boron compounds such as “LR147” (manufactured by Nippon Carlit), fluorine compounds such as magnesium fluoride and carbon fluoride, and the like. In addition to the metal complexes used as negative charge control agents, oxycarboxylic acid metal complexes, dicarboxylic acid metal complexes, amino acid metal complexes, diketone metal complexes, diamine metal complexes, azo group-containing benzene-benzene derivatives Those having various structures such as a skeletal metal body and an azo group-containing benzene-naphthalene derivative skeleton metal complex can be used.

  As described above, when the toner is configured to contain the charge control agent, the chargeability of the toner is improved.

  Further, a magnetic powder may be contained. As the magnetic powder, for example, magnetite, γ-hematite, various ferrites, or the like can be used.

  The content ratio of the magnetic powder is preferably 10 to 500% by mass in the toner particles, and more preferably 20 to 200% by mass.

  When a charge control agent and / or magnetic powder is contained, these are preferably contained in the shell layer.

(Formation method of layer A (shell layer))
The layer A is obtained by mixing the dispersion liquid (1) and the dispersion liquid (2), and a core-shell type toner can be produced. After mixing, the flocculant is added and the pH is adjusted. It is preferable to adhere the shell layer-containing particles containing the second resin so as to cover the surfaces of the core particles.

  For example, a flocculant is added to the dispersion (1) of the core particles, and then the dispersion (2) containing the second resin is added, the pH is adjusted and the temperature is adjusted, and the second resin is formed on the surface of the core particles. Can be aggregated and fused, and the surface of the core particle can be covered with a layer A (shell layer) containing the second resin.

  Further, a method in which the preparation of the core particles and the coating of the layer A are performed almost simultaneously as in the following emulsion association method can be preferably applied.

  For example, using an emulsion association method, the flocculant is added to the aqueous medium mixed with the first resin dispersion, the colorant dispersion, and, if necessary, the release agent dispersion, and the temperature is adjusted. By adding the dispersion (2) to the core particle dispersion prepared by agglomerating and fusing at the same time as the salting out, the particles for the shell layer containing the second resin on the surface of the core particles For example, a method of preparing an associating liquid containing core-shell type particles having a layer A (shell layer) covering the surface of the core particles.

The volume-based median diameter D _50v of the particles for the shell layer is preferably 30 nm or more and 300 nm or less, and more preferably 50 nm or more and 250 nm or less.

  By setting the volume-based median diameter within the above range, the shell layer can be formed uniformly, which is preferable.

  As the flocculant used, a surfactant and an inorganic metal salt can be preferably used.

  Examples of the inorganic metal salt include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate, and polyaluminum chloride, polyaluminum hydroxide, calcium polysulfide, and polysilica. Examples thereof include inorganic metal salt polymers such as iron. Of these, magnesium salts and aluminum salts are particularly preferred. In order to obtain a sharper particle size distribution, the valence of the inorganic metal salt is preferably divalent or trivalent from the viewpoints of controllability of toner particle diameter and production stability.

(Crosslinking process)
In the crosslinking step, the layer A obtained as described above is treated with an oxidant solution containing an oxidant to crosslink the second resin.

(Oxidant solution)
Examples of the oxidizing agent used in the oxidizing agent solution include ferricyanide salts such as potassium ferricyanide and sodium ferricyanide, hypochlorite salts such as sodium hypochlorite and potassium hypochlorite, potassium chlorite, Chlorates such as sodium chlorate, chlorates such as potassium chlorate, barium chlorate, calcium chlorate, sodium chlorate, ammonium chlorate, potassium perchlorate, sodium perchlorate, ammonium perchlorate, etc. Perchlorates, permanganates such as potassium permanganate, ammonium permanganate, sodium permanganate, bromates such as potassium bromate, sodium bromate, magnesium bromate, potassium dichromate, heavy Dichromates such as ammonium chromate, iodates, periodate Boronates, perborates, percarbonates, peracetates, hydrogen peroxide, peroxides such as organic peroxides, nitrates such as nitrites, potassium nitrate, sodium nitrate, barium nitrate, ammonium nitrate, etc. Can be mentioned. Of these, sodium hypochlorite and potassium ferricyanide are particularly preferably used.

  The solvent for the oxidant solution is preferably water, but may contain an organic solvent such as water-soluble alcohols.

  The treatment of layer A with an oxidant solution refers to a treatment in which the oxidant solution is brought into contact with the surfaces of the particles having the layer A obtained as described above.

  As a method for contacting, for example, a method of mixing an oxidizing agent solution in an association liquid containing core-shell type particles dispersed as described above, a dipping method of directly contacting the extracted particles, and the like can be applied.

  In the method of mixing in the association liquid, the treatment of the oxidant solution is performed by, for example, cooling rate of −5 ° C./min after the production of the association liquid containing the core-shell type particles having the layer A dispersed as described above. It is preferable to carry out after cooling.

  The temperature of the solution during the oxidant treatment is preferably 5 to 15 ° C., and the treatment time for the treatment with the oxidant solution is preferably 2 to 8 hours.

  In the cross-linking step, the second resin is cross-linked by the oxidizing agent and has the following cross-linked structure.

  Therefore, the surface of the shell layer containing the second resin of the toner produced by the production method of the present invention has the above-mentioned crosslinked structure, that is, only the surface of the shell layer has the above-mentioned crosslinked structure.

  From the above, it can be inferred that the reason why the toner produced by the production method of the present invention exhibits the effects of the present invention is as follows.

  That is, the toner produced by the production method of the present invention contains a specific cross-linked polymer, and the specific cross-linked polymer has a characteristic that a bond between imidazole rings is cleaved by application of pressure. It is. When this cleavage occurs, the molecular weight of the specific crosslinked polymer inevitably decreases.

  This molecular weight reduction due to cleavage also occurs due to the pressure applied by the fixing device, and the glass transition point and the melting characteristic curve of the toner shift to the low temperature side. Accordingly, the melting of the toner is accelerated even at a low heating temperature, and as a result, sufficient low-temperature fixability can be obtained.

  On the other hand, in the state before the pressure is applied, the specific cross-linked polymer has improved heat-resistant storage property because the micro Brownian motion due to heat is suppressed.

  Further, since the toner particles are reinforced by the crosslinking points, even if the fixing temperature is low, a large particle strength that is resistant to stress due to stirring or the like can be obtained.

  In particular, among such toners, those of the core-shell type are made stronger by forming a specific shell by cross-linking after forming a dense shell. As a result, the toner can be fixed at a low temperature while maintaining heat resistance as compared with a toner that is shelled with crosslinked particles, and the strength of the particles is further improved.

  The particle diameter of the particles that are the core-shell type toner after the crosslinking step is preferably 4 to 10 μm, and more preferably 6 to 9 μm, for example, on a volume basis median diameter.

  When the volume-based median diameter is in the above range, the transfer efficiency is increased, the image quality of halftone is improved, and the image quality of fine lines and dots is improved.

  The volume-based median diameter of particles is measured and calculated using a measuring device in which a data processing computer system (Beckman Coulter) is connected to "Coulter Multisizer TA-III" (Beckman Coulter). It is. Specifically, 0.02 g of toner is added to 20 ml of a surfactant solution (for example, a surfactant solution in which a neutral detergent containing a surfactant component is diluted 10-fold with pure water for the purpose of dispersing the toner). After mixing, ultrasonic dispersion is performed for 1 minute to prepare a toner dispersion, and this toner dispersion is displayed on the beaker containing “ISOTONII” (manufactured by Beckman Coulter) in the sample stand. Pipette until the concentration is 5-10%. Here, a reproducible measurement value can be obtained by setting the concentration range. In the measurement apparatus, the measurement particle count is 25000, the aperture diameter is 50 μm, the frequency value is calculated by dividing the measurement range of 1 to 30 μm into 256, and the volume integrated fraction is 50 % Particle diameter was defined as the volume-based median diameter.

  In addition, with respect to the individual toner particles constituting the toner, the average circularity represented by the following formula (T) is preferably 0.930 to 1.000, more preferably 0, from the viewpoint of improving transfer efficiency. .950 to 0.995.

Formula (T): Average circularity = peripheral length of circle determined from equivalent circle diameter / perimeter length of projected particle image The toner according to the present invention may contain a release agent.

  The release agent used when the release agent is contained in the toner of the present invention is not particularly limited, and examples thereof include polyethylene wax, oxidized polyethylene wax, polypropylene wax, oxidized polypropylene wax, carnauba. There may be mentioned wax, sazol wax, rice wax, candelilla wax, jojoba oil wax, beeswax wax and the like.

  As a method for incorporating a release agent in the toner, as described above, a method in which the particles of the first resin are configured to contain a release agent, for example, salting out, agglomeration, and melting to form toner particles. In the attaching step, a method of adding a dispersion liquid in which release agent particles are dispersed in an aqueous medium can be mentioned, and these methods may be combined.

  The content ratio of the release agent in the toner particles is usually 0.5 to 25 parts by mass with respect to 100 parts by mass of the binder resin, from the viewpoint of the offset prevention effect, translucency and color reproducibility, and preferably Is 4 to 12 parts by mass.

  The particles that have undergone the crosslinking step can be used as toners as they are, but preferably undergo the following washing / drying step and post-treatment step.

(Washing / drying process)
In this step, the toner particles are filtered off from the aqueous medium, unnecessary substances such as surfactants are removed from the toner particles by a cleaning process, and the cleaned toner particles are dried.

(Post-processing process)
In order to improve fluidity, chargeability, cleaning properties, and the like, external additives such as a fluidizing agent and a cleaning aid may be added to the toner particles.

  As the post-treatment agent, for example, inorganic oxide fine particles composed of silica fine particles, alumina fine particles, titanium oxide fine particles, etc., inorganic stearate compound fine particles such as aluminum stearate fine particles, zinc stearate fine particles, or strontium titanate, titanium Inorganic titanic acid compound fine particles such as zinc acid are listed. These can be used individually by 1 type or in combination of 2 or more types.

  These inorganic fine particles are preferably subjected to surface treatment with a silane coupling agent, a titanium coupling agent, a higher fatty acid, silicone oil or the like in order to improve heat-resistant storage stability and environmental stability.

  The total amount of these various external additives added is 0.05 to 5 parts by mass, preferably 0.1 to 3 parts by mass with respect to 100 parts by mass of the toner. In addition, various external additives may be used in combination.

(Developer)
The toner produced by the production method of the present invention can be used as a magnetic or non-magnetic one-component developer, but may be mixed with a carrier and used as a two-component developer.

  In the case where the toner produced by the production method of the present invention is used as a two-component developer, the carrier is conventionally a metal such as iron, ferrite, or magnetite, or an alloy of such a metal with a metal such as aluminum or lead. From the above, magnetic particles made of a known material can be used, and ferrite particles are particularly preferable. Further, as the carrier, a coat carrier in which the surface of the magnetic particles is coated with a coating agent such as a resin, a binder type carrier in which a magnetic fine powder is dispersed in a binder resin, or the like may be used.

  The coating resin constituting the coat carrier is not particularly limited, and examples thereof include olefin resins, styrene resins, styrene-acrylic resins, silicone resins, ester resins, and fluorine resins. Moreover, it does not specifically limit as resin which comprises a resin dispersion type carrier, A well-known thing can be used, For example, a styrene-acrylic-type resin, a polyester resin, a fluororesin, a phenol resin etc. can be used.

  The volume-based median diameter of the carrier is preferably 20 to 100 μm, and more preferably 20 to 60 μm. The volume-based median diameter of the carrier can be typically measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by SYMPATEC) equipped with a wet disperser.

(Image forming method)
The toner produced by the production method of the present invention can be suitably used in an image forming method including a fixing step by a heat and pressure fixing method in which pressure can be applied and heated.

  In this image forming method, specifically, the toner as described above is used, for example, an electrostatic latent image formed on a photoreceptor is developed to obtain a toner image, and this toner image is used as an image support. Then, the toner image transferred onto the image support is fixed on the image support by a fixing process using a thermal pressure fixing method, whereby a printed matter on which a visible image is formed is obtained.

  The application of pressure and heating in the fixing step are preferably simultaneous, and the pressure may be applied first and then heated.

The pressure to be applied to the toner particles constituting the toner image transferred onto the image support is, for example, (i) a contact load between the heating roller and the pressure roller in a heat roller type fixing device described later. May be a pressure at which is 40 to 350N. Further, for example, in the (ii) film heating type fixing device to be described later, it is sufficient that the surface pressure of the fixing belt with respect to the image support is 9 × 10 ^{3 to} 5 × 10 ⁵ N / m ² .

As the fixing device of the thermal pressure fixing method in the image forming method using the toner according to the present invention, various known devices can be employed. Hereinafter, a heat roller type fixing device and a film heating type fixing device will be described as the thermal pressure fixing device.
(I) Heat roller type fixing device Generally, a heat roller type fixing device is provided with a roller pair of a heating roller and a pressure roller in contact with the heating roller, and the pressure applied between the heating roller and the pressure roller. When the pressure roller is deformed, a so-called fixing nip portion is formed in the deformed portion.

  In general, the heating roller includes a metal core made of a hollow metal roller made of aluminum or the like and a heat source made of a halogen lamp or the like disposed therein, the metal core is heated by the heat source, and the outer peripheral surface of the heating roller is The temperature is adjusted by controlling energization to the heat source so as to be maintained at a predetermined fixing temperature.

  In particular, when used as a fixing device of an image forming apparatus that forms a full-color image that requires a capability of sufficiently melting and mixing a toner image composed of a maximum of four toner layers, a core metal is used as a heating roller. It is preferable to use a material having a high heat capacity and a rubber elastic layer for uniformly melting the toner image on the outer peripheral surface of the metal core.

  The pressure roller has an elastic layer made of a soft rubber such as urethane rubber or silicon rubber.

  As the pressure roller, for example, a metal core made of a hollow metal roller made of aluminum or the like and having an elastic layer formed on the outer peripheral surface of the metal core may be used.

  Furthermore, when the pressure roller is configured to have a metal core, a heat source such as a halogen lamp is disposed inside the pressure roller, and the metal core is heated by the heat source. Alternatively, the temperature may be adjusted by controlling the power supply to the heat source so that the outer peripheral surface of the heat source is maintained at a predetermined fixing temperature.

  As these heating rollers and / or pressure rollers, as the outermost layer, a mold release made of a fluororesin such as polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) or the like is used. It is preferable to use a layer formed. The thickness of the release layer can be approximately 10 to 30 μm.

  In such a heat roller type fixing device, the roller pair is rotated and the image support to form a visible image is sandwiched and conveyed in the fixing nip portion, whereby the heating by the heating roller and the pressure in the fixing nip portion are reduced. Thus, an unfixed toner image is fixed on the image support.

(Ii) Film heating type fixing device Generally, a film heating type fixing device is made of, for example, a heating body made of a ceramic heater, a pressure roller, and a heat resistant film between the heating body and the pressure roller. The fixing film is sandwiched, and the pressure roller is deformed by the pressure applied between the heating body and the pressure roller, so that a so-called fixing nip portion is formed in the deformed portion. .

  As the fixing film, a heat-resistant film made of polyimide or the like, a sheet or a belt is used, and the heat-resistant film, sheet or belt made of polyimide or the like is used as a film substrate, and tetrafluoro is formed on the film substrate. A release layer made of a fluororesin such as ethylene (PTFE) or tetrafluoroethylene-perfluoroalkyl ether copolymer (PFA) may be formed, and further, a film substrate and a release layer Between the two, an elastic layer made of rubber or the like may be provided.

  In such a film heating type fixing device, an image support carrying an unfixed toner image is nipped and conveyed together with the fixing film between a fixing film forming a fixing nip portion and a pressure roller. Thus, heating by the heating body through the fixing film and application of pressure at the fixing nip portion are performed, whereby an unfixed toner image is fixed on the image support.

  According to such a film heating type fixing device, the heating body only needs to be energized to generate heat at a predetermined fixing temperature only during image formation. Quick start performance with a short waiting time until image formation can be performed is obtained, power consumption during standby of the image forming apparatus is extremely small, and power saving can be achieved.

(Image support)
The image support used in the image forming method using the toner produced by the production method of the present invention is a coated printing paper such as plain paper, fine paper, art paper or coated paper from thin paper to thick paper. Various types of paper such as commercially available Japanese paper and postcard paper, plastic films for OHP, and cloth can be used, but the invention is not limited to these.

  According to the toner as described above, a crosslinked polymer is contained, and the crosslinked polymer has a characteristic that the bond between the imidazole rings of the triarylimidazole group is cleaved by application of pressure. By applying pressure, the glass transition point is changed to a lowered one, and by applying pressure and heating, a sufficiently low state of elastic modulus can be obtained early on the toner even at a low heating temperature, As a result, sufficient low-temperature fixability can be obtained. On the other hand, in the state before the pressure is applied, the specific crosslinked polymer has heat-resistant storage stability because the micro Brownian motion due to heat is suppressed. Therefore, according to such a toner, sufficient low-temperature fixability can be obtained while heat-resistant storage stability is obtained.

  In addition, according to such a toner, a sufficiently reduced state of the elastic modulus of the crosslinked polymer due to the application of pressure can be obtained at an early stage, so that sufficient high-speed fixability can also be obtained.

  Hereinafter, specific examples of the present invention will be described, but the present invention is not limited thereto. In the following, the volume-based median diameter, peak molecular weight, and glass transition point of the toner were measured by the same method as described above. The peak molecular weight and glass transition point measured using the toner as a measurement sample were used as the peak molecular weight and glass transition point of the crosslinked polymer.

<Preparation of particle dispersion of core resin (first resin) 1 (styrene acrylic resin)>
Reaction solution Styrene 240 parts by weight Butyl acrylate 130 parts by weight Acrylic acid 6 parts by weight A solution obtained by mixing and dissolving 24 parts by weight of Tertiary decyl mercaptan, polyoxyethylene lauryl ether “E-700” (manufactured by Nippon Emulsion) 6 In an aqueous medium in which 10 parts by mass and 10 parts by mass of sodium n-dodecylbenzenesulfonate are dissolved in 1550 parts by mass of ion-exchanged water, the mixture is dispersed and emulsified in a flask. Nitrogen substitution was performed by adding 50 parts by mass of ion-exchanged water in which 11 parts by mass of potassium was dissolved.

  Next, while stirring the inside of the flask with an oil bath until the content reaches 70 ° C. and continuing the emulsion polymerization for 5 hours, the solid content of the core resin (first resin) particles is 20 parts by mass. As a result, a particle dispersion of the core resin (first resin) 1 (styrene acrylic resin) was obtained. The volume-based median diameter of the particles was 152 nm.

  Moreover, the glass transition point of the obtained core resin (first resin) 1 was 21 ° C., and the peak molecular weight determined by GPC measurement was 19,200.

<Preparation of particle dispersion of core resin (first resin) 2 (polyester resin)>
A total of 3 parts by mass of the following polycarboxylic acid monomer and polyhydric alcohol monomer were mixed in a flask equipped with a stirrer, a nitrogen introduction tube, a temperature controller, and a rectifying column to prepare a reaction solution. The reaction solution was heated to 190 ° C. over 1 hour, and after confirming that the reaction system was uniformly stirred, the catalyst Ti (OBu) ₄ (total amount of the carboxylic acid component of the non-crystalline polyester resin was adjusted. In contrast, 0.003 mass%) was added.

Reaction liquid (polycarboxylic acid monomer)
Terephthalic acid 10 parts by weight Fumaric acid 60 parts by weight Adipic acid 30 parts by weight (polyhydric alcohol monomer)
Polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane
75 parts by mass of polyoxyethylene (2,2) -2,2-bis (4-hydroxyphenyl) propane
25 parts by mass While distilling off the water produced, the temperature was increased from the same temperature to 240 ° C. over 6 hours, and the dehydration condensation reaction was continued at 240 ° C. for another 6 hours to conduct polymerization. Resin (first resin) 2 (polyester resin) was obtained.

  The obtained core resin (first resin) 2 had a glass transition point of 40 ° C. and a peak molecular weight of 18,000 as measured by GPC.

  400 parts by mass of “core resin (first resin) 2 (polyester resin)” was added to 1700 parts by mass of ethyl acetate, and the mixture was heated to 70 ° C. and dissolved and mixed to obtain “resin solution 1”.

  Separately, 2000 parts by mass of ion-exchanged water and 4.8 parts by mass of sodium dodecyl sulfate were stirred and dispersed to prepare “Aqueous Phase 1” which becomes a continuous phase. In this “aqueous phase 1”, “resin solution 1” is added while stirring with “TK Homomixer Mark II2.5” (manufactured by PRIMIX Co., Ltd.), and “oil droplet 1” is adjusted by adjusting the stirring speed. Prepared. Then, it distilled under reduced pressure at 50 degreeC, ethyl acetate was removed, and the particle dispersion liquid dispersion 2 of core resin (1st resin) 2 (polyester resin) whose solid content is 20 mass parts was obtained. The volume-based median diameter was 180 nm.

<Preparation of particle dispersion for shell layer>
Vinyl-triphenylimidazole compounds (1) to (5) 85 parts by mass Styrene 205 parts by mass 80 parts by mass of butyl acrylate 6 parts by mass Acrylic acid 6 parts by mass A solution in which 24 parts by mass of tertiary decyl mercaptan was mixed and dissolved was polyoxyethylene. Disperse by adding 6 parts by weight of lauryl ether “E-700” (manufactured by Nippon Emulsion) and 10 parts by weight of sodium n-dodecylbenzenesulfonate in 550 parts by weight of ion-exchanged water in a flask. The mixture was emulsified and slowly mixed for 10 minutes, and then 50 parts by mass of ion-exchanged water in which 4 parts by mass of potassium persulfate was dissolved was added to perform nitrogen substitution.

  Next, while stirring the inside of the flask with an oil bath until the content reached 70 ° C., emulsion polymerization was continued for 5 hours to obtain an emulsion.

  Shell layer particles 1 to 5 having the second resin having physical properties shown in the following table dispersed therein were obtained using 1 to 5 synthesized below for vinyl-triphenylimidazole compounds.

  Similarly, particles 6 for a shell layer for a comparative example were produced as shown below.

Vinyl-triphenylimidazole compound (3) 70 parts by mass Styrene 240 parts by mass Butyl acrylate 60 parts by mass Acrylic acid 6 parts by mass Terrestrial decyl mercaptan 24 parts by mass were mixed to obtain an emulsion by emulsion polymerization as described above. The obtained emulsion is cooled to 10 ° C. at a cooling rate of −5 ° C./min, 10 parts by weight of 1% aqueous potassium ferricyanide solution is added, and the mixture is reacted at a temperature of 10 ° C. for 6 hours, and then undergoes a crosslinking step. Thus, particles 6 for a shell layer having dispersed therein were obtained.

[Synthesis example 1 of vinyl-triphenylimidazole compound]
In the reaction vessel,
Benzoin (2-hydroxy-1,2-diphenylethanone) 1609 parts by weight 3-vinylbenzaldehyde 1002 parts by weight Ammonium acetate 5838 parts by weight Boron tetrafluoride 1603 parts by weight, and heated to 100 ° C., Stirring was continued for 1.5 hours. After completion of the reaction, the reaction mixture was diluted with water, and the resulting solid was filtered, washed repeatedly with water, dried, and then subjected to silica gel column chromatography with a mixed solvent of hexane / ethyl acetate (mass ratio 9: 1). After purification by using, recrystallization with a mixed solvent of methanol / dichloroethane (mass ratio 9: 1), vinyl-triphenylimidazole compound [1] which is a compound represented by the general formula (2) was obtained.

[Synthesis Example 2 of Vinyl-Triphenylimidazole Compound]
In the reaction vessel,
A mixed solution consisting of 3090 parts by mass of 2- (p-aminophenyl) 4,5-diphenylimidazole and 925 parts by mass of methacrylic acid chloride was added, and stirring was continued at 10 ° C. for 1.5 hours. After completion of the reaction, it is diluted with 0.1N aqueous sodium hydroxide solution, and the resulting solid is filtered, washed repeatedly with water, dried, and then mixed with a mixed solvent of hexane / ethyl acetate (mass ratio 9: 1). Then, after purification using silica gel column chromatography, re-crystallization with a mixed solvent of methanol / dichloroethane (mass ratio 9: 1), vinyl-triphenylimidazole compound which is a compound represented by the general formula (2) [ 2] was obtained.

[Synthesis Example 3 of Vinyl-Triphenylimidazole Compound]
In Synthesis Example 2 of vinyl-triphenylimidazole compound, 3100 parts by mass of 2- (p-hydroxyphenyl) 4,5-diphenylimidazole was used instead of 3090 parts by mass of 2- (p-aminophenyl) 4,5-diphenylimidazole. A vinyl-triphenylimidazole compound [3], which is a compound represented by the general formula (2), was obtained in the same manner except that it was used.

[Synthesis Example 4 of Vinyl-Triphenylimidazole Compound]
In Synthesis Example 2 of the vinyl-triphenylimidazole compound, vinyl which is a compound represented by the general formula (2) is similarly obtained except that 710 parts by mass of vinyl isocyanate is used instead of 925 parts by mass of methacrylic acid chloride. -Triphenylimidazole compound [4] was obtained.

[Synthesis Example 5 of Vinyl-Triphenylimidazole Compound]
In Synthesis Example 2 of vinyl-triphenylimidazole compound, instead of 3090 parts by mass of 2- (p-aminophenyl) 4,5-diphenylimidazole and 925 parts by mass of methacrylic acid chloride, 2- (p-hydroxyphenyl) 4,5 -Vinyl-triphenylimidazole compound [5] which is a compound represented by General formula (2) was obtained similarly except having used 3100 mass parts of diphenylimidazole and 710 mass parts of vinyl isocyanate.

<Preparation of colorant fine particle dispersion>
6 parts by weight of a nonionic surfactant “E-700” (manufactured by Nippon Emulsion Co., Ltd.) is dissolved in 200 parts by weight of ion-exchanged water while stirring, and carbon black “Regal 99R” (Cabot) is used as a colorant while continuing stirring. 50 parts by mass) were gradually added, and then dispersed for 10 minutes with a homogenizer “Ultra Turrax” (manufactured by IKA) to prepare a colorant fine particle dispersion in which colorant fine particles were dispersed.

  When the particle diameter of the colorant fine particles in this colorant fine particle dispersion was measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.), the volume-based median diameter was 220 nm.

<Preparation of release agent fine particle dispersion>
6 parts by mass of a nonionic surfactant “E-700” (Japan Emulsion Co., Ltd.) is stirred and dissolved in 200 parts by mass of ion-exchanged water, and paraffin wax “HNP-0190” ( (Nippon Seiki Co., Ltd.) 50 parts by mass was added, heated to 95 ° C., and then dispersed with a homogenizer “Ultra Turrax T50” (IKA) for 10 minutes to disperse the release agent fine particles. A release agent fine particle dispersion was prepared.

  The particle diameter of the release agent fine particles in this release agent fine particle dispersion was measured using “MICROTRAC UPA 150” (manufactured by Nikkiso Co., Ltd.), and the volume-based median diameter was 250 nm.

<Preparation of Toner Particle [1]>
272 parts by mass (converted to solid content) of core resin 1 (styrene acrylic resin), 1088 parts by mass of ion-exchanged water, 98 parts by mass of the colorant particle dispersion, and 243 parts by mass of the release agent fine particle dispersion, thermometer, cooling It was put into a separable flask equipped with a tube, a nitrogen introducing device and a stirring device. Furthermore, the pH in which the aqueous sodium hydroxide solution (25% by mass) was added was adjusted to 10 while maintaining the temperature in the system at 30 ° C.

  Next, an aqueous solution in which 54.3 parts by mass of magnesium chloride hexahydrate is dissolved in 54.3 parts by mass of ion-exchanged water is added, and then the temperature in the system is raised to 55 ° C. The aggregation reaction between the resin particles (first resin) and the colorant particles was started.

After the start of the agglutination reaction, sampling is periodically performed, and the particle size distribution measuring device “Coulter Multisizer 3” (manufactured by Beckman Coulter) is used, and the median diameter (D ₅₀ ) on the volume basis of the particles is 6.0 μm. Then, 857 parts by mass of the shell layer particles 1 (second resin) forming the shell layer of the toner was added.

  When the shell layer was formed, 20.1 parts by mass of ethylenediaminetetraacetic acid was added.

  At this time, the circularity of the toner particles was 0.92.

  By raising the temperature to 75 ° C. and holding it for 3 hours, the circularity of the toner particles reaches 0.96, and then the suspension is cooled to 10 ° C. at a cooling rate of −5 ° C./min. 10 parts by mass of a 1% aqueous sodium hypochlorite solution as a solution was added and reacted at a temperature of 10 ° C. for 6 hours to crosslink the second resin.

  The reaction product in the dispersion was filtered, washed thoroughly with ion-exchanged water, and dried to obtain black toner particles [1] that had undergone a crosslinking step.

  The reaction product in the dispersion was filtered, washed thoroughly with ion-exchanged water, and dried to obtain black toner particles [1].

100 parts by mass of this toner particle [1], 0.7 parts by mass of hydrophobic silica fine powder (BET value: 200 m ² / g, primary particle size: 12 nm) as an external additive, and rutile titanium oxide fine powder (primary particles) Toner [1] was obtained by mixing 0.05 part by mass of a diameter (250 nm) using a Henschel mixer (manufactured by Mitsui Miike Chemical Co., Ltd.).

  Similarly, toner [12] was produced from toner [2] under the conditions shown in the following table.

  In toners [11] and [12], 1% potassium ferricyanide was used in place of sodium hypochlorite as an oxidizing agent.

  Comparison of the toners [1] to [12] with the infrared absorption spectra of the vinyl-triphenylimidazole compounds [Synthesis Example 1] to [Synthesis Example 5] corresponding to Table 1, respectively, and the above-described crosslinking cleavage treatment As a result of confirmation of radical generation by electron spin resonance analysis (ESR) for those subjected to the treatment, and the insoluble content of tetrahydrofuran disappeared for those subjected to the cross-linking cleavage treatment, the structure portion represented by the general formula (3) is included. It was confirmed.

  In Comparative Examples 1 and 2, as the shell layer particles, the previously cross-linked shell layer particles 6 were added, the temperature was raised to 95 ° C. and held for 4 hours, whereby the circularity of the toner particles was reduced to 0.1. The toner particles [A] and [B] were obtained.

Furthermore, the toner used in Example 1 of Patent Document 1 was also produced, and toner particles [C] were obtained. (Comparative Example 3)
[Preparation of two-component developer]
100 parts by mass of ferrite particles (volume-based median diameter: 50 μm (manufactured by Powdertech)) and 4 parts by mass of methyl methacrylate-cyclohexyl methacrylate copolymer resin (volume-based median diameter of primary particles: 85 nm) The mixture was placed in a stirring blade type high-speed stirring device and mixed for 15 minutes under the conditions of the peripheral speed of the stirring blade: 8 m / s and the temperature: 30 ° C., then the temperature was raised to 120 ° C. and stirring was continued for 4 hours. Then, it cooled and the resin-coated carrier was produced by removing the fragment of methyl methacrylate-cyclohexyl methacrylate copolymer resin using a 200 mesh sieve.

  The resin-coated carrier is mixed with each of the toners [1] to [12] and the comparative toners [A] and [B] so that the toner concentration becomes 7% by mass, and a two-component developer 1 to 12 and comparative two-component developer comparisons 1 and 2 were prepared.

(Evaluation)
Evaluation items (1) to (3) below were evaluated using the two-component developers 1 to 12 and the comparative two-component developer comparisons 1 and 2. The results are shown in Table 3.

(1) Low-temperature fixability Using a commercially available digital copying machine “bizhub 920” (manufactured by Konica Minolta Business Technologies), the surface temperature of the fixing heating member was changed so as to change in increments of 5 ° C. in the range of 80 to 150 ° C. At each temperature, a toner image is fixed using 350 g of paper as an image support in an environment of room temperature and room temperature (temperature 20 ° C., humidity 50% RH) to obtain a printed material, and an image portion of the printed material The fixing strength was measured by the following mending tape peeling method, and the temperature of the fixing heating member when the fixing strength was 90% or more was evaluated as the fixing possible temperature. Note that if the fixable temperature is 110 ° C. or lower, it is determined to be acceptable.

-Mending tape peeling method-
1) The absolute reflection density D ₀ in the image portion of the printed matter (image density 1.3) is measured, and then the printed matter is folded in half so as to pass through the image portion.
2) Lightly affix the mending tape “No.810-3-12” (manufactured by Sumitomo 3M) to the image portion of the printed material that is folded in half.
3) Rub 4 times on the mending tape at a pressure of 1 kPa.
4) Remove the mending tape with an angle of 180 degrees and a force of 2N.
5) measuring the absolute reflection density D ₁ of the said image portions after peeling.
6) The fixing rate is calculated based on the following formula (D).

Formula (D): Fixing strength (%) = D ₁ / D ₀ × 100
For the measurement of absolute reflection density, a reflection densitometer “RD-918” (manufactured by Macbeth Co.) was used.

(2) Heat-resistant storage property Take 0.5 g of toner in a 10 ml glass bottle with an inner diameter of 21 mm, close the lid, shake it 600 times at room temperature using a tap denser “KYT-2000” (manufactured by Seishin Enterprise), and then remove the lid. It was left for 2 hours in an environment of temperature 55 ° C. and humidity 35% RH. Next, place the toner on a 48 mesh (350 μm aperture) sieve, taking care not to crush it, set it on a powder tester (manufactured by Hosokawa Micron), fix it with a press bar and knob nut, and adjust the vibration strength to 1 mm. After adjusting and applying vibration for 10 seconds, the amount of residual toner remaining on the sieve was measured, and the toner aggregation rate was calculated by the following formula (1) and evaluated.

Formula (1): toner aggregation rate (%) = {residual toner amount (g) /0.5 (g)} × 100
In addition, when the toner aggregation rate is less than 15%, it is judged that the heat resistant storage property of the toner is extremely good, and when the toner aggregation rate is 15% or more and 20% or less, the heat resistant storage property of the toner is good. If the toner aggregation rate exceeds 20%, it is determined that the toner has poor heat storage stability and cannot be practically used.

(3) Toner scattering prevention property The toner particle strength was determined as follows and used as an index of toner scattering prevention property.

  A two-component developer is set in a developing device of a commercially available digital copying machine “bizhub 920” (manufactured by Konica Minolta Business Technologies), and an electrostatic latent image is not formed on the photosensitive member, that is, under a potential condition where toner is not developed. An agitation test is performed for agitation for a period of time, and then the toner is taken out, and the particle size distribution of the toner is measured using a flow type particle image analyzer “FPIA-2100” (manufactured by Sysmec Co., Ltd.). The particle strength index represented by the following formula (M) was calculated and evaluated based on the particle strength index.

Formula (M): Particle strength index = {(number of particles of 1 μm or less) / (number of whole particles)} × 100
Before the stirring test, any two-component developer had a particle strength index of less than 1. When the particle strength index after the agitation test is less than 9, the toner has sufficient particle strength, and the occurrence of carrier contamination is suppressed without generating crushed fine particles of toner particles, thereby obtaining sufficient stress resistance. As a result, it is judged that the replacement cycle of the two-component developer becomes long. On the other hand, when the particle strength index exceeds 9, the surface of the carrier particle is observed when the two-component developer is visually observed with an electron microscope. The state where the toner particles are predominantly covered is observed, and the chances of the carrier particles and the toner particles being triboelectrically charged are greatly reduced. Judged not.

  From Table 3, the toner manufactured by the manufacturing method of the present invention is a simple method in which the surface of the core-shell type toner is treated with an oxidant solution, which is excellent in productivity and has a good heat-resistant storage property and at the same time. It can be seen that the toner has excellent low-temperature fixability, high particle strength, and excellent toner scattering prevention.

Claims (3)

A toner production method for producing a core-shell type toner having a core layer containing a first resin and a colorant and having a shell layer on the core layer, the method comprising the first resin and the colorant A dispersion (1) containing core particles to be dispersed, and a dispersion (2) containing particles for a shell layer containing a second resin having a triarylimidazole group represented by the following general formula (1) A shelling step of mixing and covering the core particles with the layer A containing the second resin, and treating the layer A with an oxidizing agent solution containing an oxidizing agent to crosslink the second resin A toner production method comprising a crosslinking step.

[Wherein R ¹ represents a hydrogen atom or a chlorine atom. R ² and R ³ represent a hydrogen atom, a chlorine atom or a methoxy group. ] A method for producing a toner, wherein the second resin is a resin obtained by polymerization using a polymerizable monomer represented by the following general formula (2).

[Wherein R ¹ represents a hydrogen atom or a chlorine atom. R ² and R ³ represent a hydrogen atom, a chlorine atom or a methoxy group. R ⁴ represents a hydrogen atom or a methyl group. L represents a single bond or a divalent linking group. ] A toner produced by the method for producing a toner according to claim 1, wherein the toner comprises a core layer containing the first resin and the colorant, and the general formula (1) is provided on the core layer. And a shell layer containing a second resin having a triarylimidazole group represented by the formula: wherein the surface of the shell layer has a cross-linked structure represented by the following general formula (3) .

[Wherein R ¹ represents a hydrogen atom or a chlorine atom. R ² and R ³ represent a hydrogen atom, a chlorine atom or a methoxy group. R ⁴ represents a hydrogen atom or a methyl group. L represents a single bond or a divalent linking group. ]