JP2005215607A - Electrophotographic toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner excellent in durability and fixability. <P>SOLUTION: The toner contains aggregation particles having resin particle agglomerates. The resin particle agglomerates included in the aggregation particles have a shape obtained by fusing resin particles to each other or bringing resin particles into contact with each other with boundary surfaces, and the toner has a network structure in which the resin particle agglomerates combine with each other only at surfaces. The boundary surfaces are combined through a network forming agent and this network forming agent exists locally on the boundary surfaces. Such a toner is prepared by preparing resin particles using a monomer having a functional group such as a carboxyl group or an epoxy group, and by bonding functional groups in the resin particles to each other through a network forming agent such as a crosslinking agent, a reactive monomer, a reactive polymer, a polymerizing agent, an auxiliary polymerizing agent or a polymerization initiator. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a toner used for developing an electrostatic latent image in electrophotography, electrostatic recording, electrostatic printing, and the like and forming an image by thermal fixing.

  In general, a toner for forming an electrostatic image is obtained by melting and kneading a colorant or the like in a toner resin (binder resin) such as a polyester resin or a styrene / acrylic copolymer resin, followed by pulverization and classification. ing. However, since the toner obtained by this pulverization method has low sphericity, it has poor fluidity (smoothness) and inferior transferability as compared with toner having high sphericity (closer to a true sphere). Furthermore, in recent years, there has been a demand for higher image quality of printers, and there has been a movement to reduce the toner particles. However, in the pulverization method, there are problems of pulverization, classification, etc. Is difficult to obtain.

  In order to solve such problems, attempts have been made to produce a toner (polymerized toner) by a polymerization method. In general, a polymerized toner is obtained by emulsifying a monomer as a raw material of a resin by a method such as emulsion polymerization or suspension polymerization, polymerizing it in the state of emulsion, heating and aggregating it, and drying. In this heating / drying process, the polymer particles are thermally fused and partially melted or the resin particles are thermally fused to each other. However, since this bond is weak, the toner is liable to disintegrate, so that there is a problem that the durability during use is poor and the stability during storage is lacking.

  For example, in Patent Document 1, primary particles of a polymer having an acidic polar group or a basic polar group are prepared by emulsion polymerization, and colorant particles and a charge control agent are added to the primary particles and heated. It is described to obtain colored secondary particles and to obtain associated particles of the secondary particles. It is described that at least a part of the contact portion between the secondary particles is film-formed and fused, and the associated particles do not collapse during storage, transportation, and developer production. However, the toner composed of the heat-sealed secondary particles does not have sufficient strength because the bonds between the particles do not have sufficient strength, and lacks durability during use.

  Patent Document 2 discloses a polymerized toner having a small particle diameter excellent in fixability. In this polymerized toner, particles obtained by emulsifying and polymerizing a monomer composition containing a polymerizable monomer and a fixability improver are directly used as a polymerized toner to obtain a toner having a small particle diameter. In addition, it is described that a crosslinkable monomer may be added in order to improve the properties of the polymer particles when the polymer toner having a small particle diameter is produced. However, in the production of the polymerized toner, there is a possibility that bonding due to cross-linking occurs between the particles. However, since the polymerizable monomer and the cross-linking agent are mixed and emulsified, the cross-linking agent is exclusively used for this. It is considered that it is used when forming polymer particles by polymerization of monomers. Therefore, even if the polymer particles containing the crosslinked structure formed are associated with other polymer particles, the strength of the polymer particles containing the crosslinked structure itself is high, so that the resin is difficult to melt during fixing and the low-temperature fixability is deteriorated. .

  Patent Document 3 discloses a toner comprising a polymer obtained by aqueous emulsion polymerization and a colorant in the presence of a reactive surfactant. This reactive surfactant is subjected to a polymerization reaction together with a polymerizable monomer in order to adjust the charge amount of the polymer. Therefore, the reactive surfactant is incorporated into the polymer and is hardly used for bonding between particles. Therefore, the toner obtained by dehydrating or spray-drying the emulsion has a weak bond between polymer particles and lacks durability such as disintegration during storage. For this reason, Patent Document 3 discloses a complicated method in which the toner particles are produced by melting and kneading polymer particles once synthesized in the examples.

Further, Patent Document 4 discloses a toner having a capsule structure (core-shell structure) for the purpose of improving low-temperature fixability. In this method, first, a polymerizable composition containing a polymerizable monomer, a colorant and the like is subjected to suspension polymerization or emulsion polymerization, and this is agglomerated to obtain core particles, which are then separated around the core particles. The particles are agglomerated and dried as necessary to obtain toner particles having a capsule structure. Although this toner is excellent in low-temperature fixability, since the particles need to be combined only by the agglomeration force and the aggregation process must be performed twice, the durability during use is poor and the storage stability is low. There is a problem of lacking.
JP-A 63-186253 Japanese Patent Laid-Open No. 5-66611 JP-A-63-281172 Japanese Patent Laid-Open No. 11-7156

  As described above, the conventional polymerized toner has a problem that it is inferior in durability when it is excellent in low-temperature fixability. On the other hand, there is a problem in that the low-temperature fixability is lowered when durability is improved. Therefore, there is a demand for a toner that has excellent durability and low-temperature fixability. An object of the present invention is to provide a toner that is excellent in low-temperature fixability and also has durability.

  The present invention relates to a toner containing aggregate particles having resin particle lumps, wherein the resin particle lumps have a shape in which the resin particles melt or contact each other, and the aggregate particles Has a network structure with a network-forming agent, the boundary surface is bonded via the network-forming agent, and the network-forming agent is localized on the boundary surface.

  In a preferred embodiment, the network forming agent is a water-soluble crosslinking agent.

  In a preferred embodiment, the crosslink is formed by dehydration.

  In a preferred embodiment, the crosslinking agent has a functional group capable of reacting with a carboxyl group.

  In a preferred embodiment, the network forming agent is at least one selected from the group consisting of a reactive monomer, a reactive polymer, a polymerization agent, a polymerization aid, and a polymerization initiator.

  The toner of the present invention is a toner composed of agglomerated particles, but the aggregate particles constituting the toner include a resin particle lump in which the resin particles are in contact with each other with a boundary surface. The boundary surface is bonded via a network forming agent, and the network forming agent is localized at the boundary surface. Therefore, the boundary surface is relatively firmly crosslinked or bonded. As a result, compared to conventional aggregated particles that are in contact with each other at the boundary, the aggregated particles are not easily physically broken. Therefore, durability is imparted to the toner and storage stability is improved. Furthermore, the aggregate particles of the present invention have a network structure in which the resin particle masses are connected by a network, but the network is formed only on the surface of the resin particle masses, so that the resin melting properties are hindered. The fixing property is not impaired. Therefore, a toner having excellent durability and excellent low-temperature fixability is provided.

  The toner of the present invention is a “toner containing aggregate particles having a resin particle lump”, and is obtained by externally adding an additive such as negatively chargeable silica fine particles and titanium dioxide to the aggregate particles. “Aggregate particles having resin particle lumps” are resin particles lumps in which resin particles described below are in contact (preferably bonded) with a boundary surface, and resin particles formed by melting the resin particles with each other. Contains lumps. In the toner of the present invention, the resin particle lumps contained in the aggregate particles are connected by a network (that is, the aggregate particles having the resin particle lumps have a network structure).

  FIG. 1 shows a partial structure of the toner of the present invention. In FIG. 1, the toner 1 has a single resin particle 11, three resin particles melted together to form a single resin particle mass 12, two resin particles contacted, and a boundary surface 17. Resin mass lump 13 and 4 resin particles that are bonded together are fused together to form a lump resin particle lump 14 and 3 resin particles that are in contact with each other and have a boundary surface 17 to form a lump. The resin particle mass 15 and the like are cross-linked or bonded to each other, and the resin particle mass has a boundary surface 17 to form a network 16. The boundary surface 17 is cross-linked or bonded with a network forming agent. Since the network forming agent is localized on the boundary surface 17, the boundary surface 17 is bonded more strongly than the portion other than the boundary surface 17 of the resin particles. Therefore, the resin particle block bonded through the boundary surface 17 is resistant to external stress and imparts durability to the toner.

  Furthermore, the resin particle blocks 12 to 15 form a network 16 by cross-linking or bonding to the surfaces of other resin particle blocks. In this way, the boundary surface is relatively firmly cross-linked or bonded, so the resin particle lump is bonded relatively firmly and a network is formed between the resin particle lump, so it is easy even when an external force is applied It has a structure that does not collapse.

  Since the resin particle masses 12 to 15 are all generated from the single resin particle 11 of the present invention, first, (i) resin particles and (ii) the resin particles which are materials used in the present invention. And (iii) a network forming agent will be described, and then (iv) a method for manufacturing the toner of the present invention will be described.

(i) Resin Particles The toner of the present invention has a boundary surface between resin particle lumps, between resin particles, and between resin particles and resin particle lumps (hereinafter, these may be simply referred to as “between particles”). A network structure is formed between the particles while being in contact with each other, and the network formation between the particles is performed using the functional groups present in the resin particles and the resin particle mass. Therefore, the resin particles are prepared so as to have a functional group.

  Examples of functional groups that may be present in the resin particles include carboxyl groups, hydroxyl groups, epoxy groups, sulfonic acid groups, nitrogen-containing functional groups (for example, ammonium groups, amino groups, amide groups, etc.), acid anhydrides, and the like. Group, N-alkoxymethyl group, N-methylol group and the like, but are not limited thereto. Preferred are a carboxyl group, a hydroxyl group, an epoxy group, a sulfonic acid group, a functional group containing nitrogen, and an acid anhydride group, and more preferred are a carboxyl group, a hydroxyl group, and an epoxy group. The type of functional group in the resin particle may be one type or two or more types. Examples of the resin having the functional group include, but are not limited to, the following resins.

  Examples of the resin having a carboxyl group include (meth) acrylic acid polymers such as poly (meth) acrylic acid, methyl methacrylate- (meth) acrylic acid copolymer, and acrylic acid-polyvinyl alcohol copolymer; methyl Examples thereof include vinyl ether-maleic acid copolymers; styrene polymers such as styrene-maleic acid copolymers and styrene- (meth) acrylic acid copolymers.

  Examples of the resin having a hydroxyl group include polyalkylene oxides such as polyethylene oxide and ethylene oxide-propylene oxide copolymers; vinyl alcohol polymers such as polyvinyl alcohol and ethylene-vinyl alcohol copolymers; ether groups and the like. Vinyl ester polymers such as polyoxyalkylene-vinyl acetate copolymers; copolymers containing hydroxy-containing (meth) acrylates; (meth) acrylic acid-polyvinyl alcohol copolymers; ethylene-maleic anhydride copolymers; And vinyl acetate-methyl acrylate copolymer. In the following description, (meth) acrylic acid is a generic term for acrylic acid and methacrylic acid, and (meth) acrylate is a generic term for acrylate and methacrylate.

  Examples of the resin containing an epoxy group include polyglycidyl (meth) acrylate, glycidyl (meth) acrylate- (meth) acrylate copolymer, styrene-glycidyl (meth) acrylate copolymer, styrene- (meth) acrylic acid-glycidyl. (Meth) acrylate copolymer etc. are mentioned.

  Examples of the resin having a sulfonic acid group include styrene polymers such as polystyrene sulfonic acid and polyvinyl sulfonic acid.

  Examples of resins having functional groups containing nitrogen include quaternary ammonium salts such as polyvinylbenzyltrimethylammonium chloride and polydiallyldimethylammonium chloride, polydimethylaminoethyl (meth) acrylate, polyvinylpyridine, polyvinylimidazole, polyethyleneimine, and polyamide polyamine. , Poly (meth) acrylamide, polydiacetone (meth) acrylamide, polyvinylpyrrolidone and the like.

  Examples of the resin containing an acid anhydride group include alkyl vinyl ether-maleic anhydride copolymers such as methyl vinyl ether-maleic anhydride copolymer; ethylene-maleic anhydride copolymer: vinyl acetate-maleic anhydride copolymer. Styrene-maleic anhydride copolymer; (meth) acrylate-maleic anhydride copolymer.

  Examples of the resin having an N-alkoxymethyl group or an N-methylol group include N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, and N-ethoxymethyl (meth) acrylamide.

  Furthermore, you may use polyester, a polyurethane, an epoxy resin, etc. which have the said functional group.

By the way, when aiming at low-temperature fixability, the flow softening point (Tf _1/2 ) of the resin used for the toner is preferably low, and from the viewpoint of storage stability, the glass transition temperature (Tg) is preferably high. From the viewpoint that the flow softening point and glass transition temperature of the resin can be easily adjusted, it is preferable that (meth) acrylic acid and (meth) acrylate-based resins are the main components, and poly (meth) acrylic acid, (meth) Acrylic acid- (meth) acrylate copolymer, styrene-functional (meth) acrylate copolymer, styrene- (meth) acrylic acid copolymer, styrene- (meth) acrylic acid- (meth) acrylate copolymer A coalescence or the like is preferably used. These resins may be used alone or in combination of two or more.

(Ii) Monomers for producing resin particles (ii-1) Types of monomers In the production of resins having the above functional groups, monomers having functional groups and functional groups are not present. Any of the monomers can be used. In order to prepare the resin particles used in the present invention, at least one monomer having a functional group is included.

  For example, the following monomers are exemplified: (meth) acrylic acid, crotonic acid, maleic acid, maleic acid half ester, itaconic acid, itaconic acid half ester, fumaric acid, fumaric acid half ester, etc. Body; hydroxyl group-containing monomers such as ethylene oxide, propylene oxide, vinyl alcohol monomers, vinyl acetate, 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate (having hydroxyl groups by reaction) Monomers containing epoxy groups such as glycidyl (meth) acrylate and allyl glycidyl ether; monomers containing sulfonic acid groups such as styrenesulfonic acid and vinylsulfonic acid; vinylbenzyltrimethylammonium chloride and diallyldimethyl Monomers containing nitrogen-containing functional groups such as ammonium chloride, dimethylaminoethyl (meth) acrylate, vinylpyridine, vinylimidazole, ethyleneimine, (meth) acrylamide, diacetone (meth) acrylamide, vinylpyrrolidone; maleic anhydride, Acid anhydride-containing monomers such as itaconic anhydride and fumaric anhydride; N-methylol group-containing monomers such as N-methylol (meth) acrylamide; N-methoxymethyl (meth) acrylamide, N-ethoxymethyl (meta ) N-alkoxymethyl group-containing monomers such as acrylamide; styrene monomers (styrene, α-methylstyrene, vinyltoluene, t-butylstyrene, chlorostyrene, etc.), vinylanisole, vinylnaphthalene, divinylbenzene, etc. Aromatic vinyl Monomers; Olefins such as ethylene, butadiene, isoprene and chloroprene; Alkyl (meth) acrylates such as (meth) acrylate and methyl (meth) acrylate; Vinyl esters such as vinyl acetate, vinyl caproate and vinyl propionate; ) Acrylonitrile; Vinyl ketones such as methyl vinyl ketone; Vinyl ethers such as methyl vinyl ether; Crotonaldehyde; Allyl alcohol; Allyl esters such as allyl acetate: etc.

  A monomer having a functional group is selected from these monomers and other known monomers, a polymer of the monomer having a functional group (homopolymer), a monomer having a functional group Or a copolymer of a monomer having a functional group and a monomer having no functional group can be prepared. When the monomer is referred to as a functional group, it does not include a polymerizable reactive group used for forming a resin such as an α, β-ethylenically unsaturated group.

  In addition, 0.1-10 mass parts is preferable with respect to 100 mass parts of monomers which do not have a functional group, and the monomer which has a functional group has 0.5-5 mass parts between suitable polymer particles. This is preferable in terms of giving a binding force of.

  As described above, since a styrene-containing resin mainly composed of a (meth) acrylic acid and a (meth) acrylate-based resin is suitable, a monomer (( (Meth) acrylate monomer, (meth) acrylic acid monomer, and styrene monomer) will be described in more detail. In addition, when it says acrylic acid, the inorganic salt (For example, metal salts, such as ammonium salt or sodium salt, potassium salt) shall also be included. Similarly, other acids (such as maleic acid) include these inorganic salts.

(Ii-2) (meth) acrylate monomers (meth) acrylate monomers include alkyl (meth) acrylates; (meth) acrylates having hydroxyl groups; (meth) acrylates having amino groups; glycidyl groups (Meth) acrylates having a polyfunctional (meth) acrylate and the like.

  Examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t- Butyl (meth) acrylate, n-amyl (meth) acrylate, isoamyl (meth) acrylate, n-hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, dodecyl ( Examples include meth) acrylate, stearyl (meth) acrylate, octadecyl (meth) acrylate, and the like.

  Examples of the (meth) acrylate having a hydroxyl group include 2-hydroxypropyl (meth) acrylate.

  Examples of the (meth) acrylate having an amino group include dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate.

  Examples of the (meth) acrylate having a glycidyl group include glycidyl (meth) acrylate.

  Examples of the polyfunctional (meth) acrylate include ethylene glycol di (meth) acrylate and trimethylolpropane tri (meth) acrylate.

  In addition, cycloalkyl (meth) acrylates such as cyclohexyl (meth) acrylate, aryl (meth) acrylates such as phenyl (meth) acrylate, benzyl (meth) acrylate, aralkyl (meth) acrylate, alkoxyalkyl (meth) acrylate, etc. are also used. it can.

(ii-3) (Meth) acrylic acid monomers (Meth) acrylic monomers include (meth) acrylic acid, methyl (meth) acrylic acid, ethyl (meth) acrylic acid, propyl (meth) Acrylic acid, isopropyl (meth) acrylic acid, n-butyl (meth) acrylic acid, isobutyl (meth) acrylic acid, t-butyl (meth) acrylic acid, pentyl (meth) acrylic acid, hexyl (meth) acrylic acid, octyl (Meth) acrylic acid, 2-ethylhexyl (meth) acrylic acid, decyl (meth) acrylic acid, dodecyl (meth) acrylic acid, stearyl (meth) acrylic acid and the like.

  Moreover, 2-hydroxypropyl (meth) acrylic acid, dimethylaminoethyl (meth) acrylic acid, diethylaminoethyl (meth) acrylic acid, glycidyl (meth) acrylic acid, ethylene glycol di (meth) acrylic acid, trimethylolpropane tri ( In addition to the carboxylic acid, a monomer that can provide a functional group (for example, a hydroxyl group) different from the carboxylic acid in the resin particles is used, such as (meth) acrylic acid.

(Ii-4) Styrene monomer Examples of the styrene monomer include styrene, α-methylstyrene, vinyltoluene, and the like. Styrene is preferably used. Styrene sulfonic acid and vinyl sulfonic acid may be used.

  In preparing the resin particles, one or more monomers are selected so as to include at least a monomer having a functional group. For example, when a styrene-acrylate copolymer is desired, since the styrene-alkyl acrylate copolymer does not have a functional group in the resin particle, styrene sulfonic acid is used instead of styrene, or alkyl acrylate A functional group is introduced into the resin particles by a method such as using glycidyl acrylate instead of. Alternatively, in addition to styrene and alkyl acrylate, a resin particle obtained by combining the (meth) acrylic acid monomer of (ii-3) or the monomer having the functional group exemplified in (ii-1) above Manufacturing.

(Iii) Network forming agent In this invention, a network forming agent means the substance which produces the coupling | bonding between particle | grains. The network forming agent includes a cross-linking agent that cross-links between functional groups present in each resin particle, or a reactive monomer, a reactive polymer, a polymerizing agent, a polymerization agent that bonds functional groups in each resin particle to each other. Auxiliaries, polymerization initiators and the like are included.

  The network forming agent used in the present invention is water-soluble, easily dispersible in water, or soluble in a trace amount of water-soluble solvent from the viewpoint of crosslinking between particles or bonding between particle surfaces in an emulsion state. It preferably has a property of being solubilized with a surfactant. In particular, in order to localize the network forming agent on the boundary surface of the resin particles, the resin forming agent is made water-soluble and dissolved in the dispersion medium of the resin particles so that the resin particles and the network forming agent are easily brought into contact with each other. It is preferable to do so.

(Iii-1) Crosslinking agent The crosslinking agent is not particularly limited as long as it is a compound capable of reacting with a functional group present in resin particles or aggregate particles to form a crosslink between the particles. A crosslinking agent can be used individually or in combination of 2 or more types.

  (Iii-1-1) When the functional group is a carboxyl group, as the crosslinking agent, a compound having an epoxy group or an isocyanate group, a metal compound, or the like is preferably used.

  As the compound having an epoxy group, a compound having two or more epoxy groups, for example, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, Glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, 1,3-3,4-diepoxybutane and the like are used.

  As the compound having an isocyanate group, a polyisocyanate compound such as tolylene diisocyanate, hydrogenated tolylene diisocyanate, diphenylmethane diisocyanate, xylene diisocyanate, hexamethylene diisocyanate, a prepolymer having an isocyanate group (hydroxyl-containing polyester, hydroxyl-containing polyether, etc.) And a polymer having an isocyanate group at the terminal) obtained by reacting the above-mentioned polyisocyanate with an excessive amount of the polyol.

  The metal compound is preferably a water-soluble metal compound having a valence of 2 or more, and a halide of a metal such as boron, aluminum, iron, copper, zinc, tin, titanium, nickel, magnesium, vanadium, chromium, zirconium, etc. And salts (carbonates, nitrates, sulfates, etc.), oxides, hydroxides and the like. In particular, boric acid, borax, aluminum chloride, aluminum sulfate, ammonium zirconium carbonate, zirconium chloride, iron alum and the like are preferable.

  (Iii-1-2) When the functional group is a hydroxyl group, the crosslinking agent includes a compound having a carboxyl group or an acid anhydride group, a compound having an aldehyde group, a compound having an epoxy group, a nitrogen-containing compound, and an acrylamide moiety. , Compounds having an isocyanate group, metal compounds, and the like. Especially, the compound (especially polyhydric carboxylic acid or its acid anhydride) which has a carboxyl group or an acid anhydride group, and a metal compound are preferable.

  Examples of the polyvalent carboxylic acid include aliphatic polycarboxylic acid, alicyclic polycarboxylic acid, aromatic polycarboxylic acid, oxypolycarboxylic acid, and heterocyclic polycarboxylic acid.

  As aliphatic polycarboxylic acid, C2-10 aliphatic saturated polycarboxylic acid (for example, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, etc.), Alternatively, C4-6 aliphatic unsaturated polycarboxylic acids (fumaric acid, maleic acid, maleic anhydride, citraconic acid, mesaconic acid, itaconic acid, etc.) and the like can be mentioned.

  Examples of the alicyclic polycarboxylic acid include C8-10 alicyclic polycarboxylic acids (for example, 1,4-cyclohexanedicarboxylic acid, tetrahydrophthalic acid, hexahydrophthalic acid, etc.).

  Examples of the aromatic polycarboxylic acid include C8-12 aromatic polycarboxylic acids or acid anhydrides thereof (for example, phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, etc.). .

  Examples of the oxypolycarboxylic acid include C3-6 oxypolyvalent carboxylic acids (eg, tartronic acid, malic acid, tartaric acid, citric acid, etc.).

  The heterocyclic polyvalent carboxylic acid is a polyvalent carboxylic acid having at least one heteroatom selected from nitrogen, oxygen and sulfur atoms (for example, pyridinedicarboxylic acid, pyridinetricarboxylic acid, pyridinetetracarboxylic acid, tropic acid, etc.) Etc. As the polyvalent carboxylic acid in the heterocyclic polyvalent carboxylic acid, an aliphatic, alicyclic or aromatic polycarboxylic acid (particularly a C3-10 polycarboxylic acid) is preferably used.

  A salt or partial salt of a polyvalent carboxylic acid is also preferably used. Examples of the polyvalent carboxylates include inorganic salts such as ammonium salts and alkali metal salts (potassium salts, sodium salts, etc.) and organic salts such as tertiary amines. As the polyvalent carboxylic acid, maleic acid or its acid anhydride (maleic anhydride) is particularly preferable.

  As the compound having an aldehyde group, a compound having a plurality of aldehyde groups, for example, glyoxal, malonaldehyde, glutaraldehyde, terephthalaldehyde, dialdehyde starch, acrolein copolymer acrylic resin and the like are used.

  Examples of nitrogen-containing compounds include C1-4 alkoxymelamines such as methoxymethylmelamine, methylol group-containing compounds such as N-methylolmelamine and N-methylolurea, guanamines such as acetoguanamine and benzoguanamine, melamine-formalin resin, urea -Formalin resin or the like is used.

  Examples of the compound having an acrylamide group include methylene-bis (meth) acrylamide, N, N′-dimethylol-methylene-bisacrylamide, 1,1-bisacrylamide-ethane and the like.

  The compound and metal compound having an epoxy group or an isocyanate group are as described in (iii-1-1) “When the functional group is a carboxyl group”.

  (Iii-1-3) When the functional group is a functional group other than a carboxyl group and a hydroxyl group, a crosslinking agent having a functional group capable of reacting with the functional group may be selected in consideration of the above explanation. For example, when the functional group is an amide group, a dihydroxy compound may be used.

(Iii-2) Network forming agents other than crosslinking agents Examples of network forming agents other than crosslinking agents include reactive monomers, reactive polymers, polymerization agents, polymerization aids, polymerization initiators and the like as described above. It is done. The reactive monomer and the reactive polymer react with a functional group in the resin particle to form a network between the resin particles.

(Iii-2-1) Reactive monomer The reactive monomer which is a network forming agent refers to a polymerizable monomer. The reactive monomer includes a monomer having a group capable of reacting with a functional group present in the resin particle (functional group-containing reactive monomer) and a functional group present in the resin particle. Any monomer that does not (functional group-free reactive monomer) is used. In order to prepare the toner of the present invention, at least one functional group-containing reactive monomer is used. The functional group-free reactive monomer is used in combination with a functional group-containing reactive monomer. As the functional group-containing reactive monomer, various monomers described in the above “(ii) Monomer for producing resin particles” can be used. For example, when the functional group of the resin particle is a carboxyl group, a monomer having an epoxy group (for example, glycidyl (meth) acrylate) is used. When the functional group of the resin particle is an epoxy group, a monomer having a carboxyl group (for example, methacrylic acid) is used. The functional group-free reactive monomer includes (a) a monomer having no functional group (for example, styrene, (meth) acrylate, olefin, etc.), and (b) a functional group present in the resin particle. Monomers having functional groups that do not react are included. The monomer corresponding to (b) is based on the functional group of the functional group-containing reactive monomer, referring to the descriptions in (iii-1-1) and (iii-1-2) above. Those skilled in the art can easily select.

(Iii-2-2) Reactive polymer A reactive polymer is a polymer that itself can be polymerized, and a polymer having a group capable of reacting with a functional group present in a resin particle (functional Both a group-containing reactive polymer) and a polymer that does not react with a functional group present in the resin particles (non-functional group-containing reactive polymer) are used. Here, the functional group of the reactive polymer does not include a polymerizable reactive group such as an α, β-ethylenically unsaturated group. In order to prepare the toner of the present invention, at least one functional group-containing reactive polymer is used. The functional group-free reactive polymer is used in combination with the functional group-containing reactive polymer. The functional group-containing reactive polymer refers to a homopolymer or copolymer obtained using a reactive monomer having at least a functional group. The functional group-free reactive polymer includes (a) a monomer having no functional group (for example, styrene, (meth) acrylate, olefin, etc.), and (b) a functional group present in the resin particle. And a homopolymer of each of the monomers having a functional group that does not, and a copolymer of the monomer (a) and the monomer (b). The monomer corresponding to (b) is based on the functional group of the functional group-containing reactive polymer, referring to the description of (iii-1-1) and (iii-1-2) above, One skilled in the art can easily select.

  Reactive polymers include dimers to oligomers and polymers. From the viewpoint of network formation, a low molecular weight is preferable. Therefore, about 2-100 mer is preferable and about 2-50 mer is more preferable.

  The reactive monomer and the reactive polymer may be used alone or in combination. For example, functional group-containing reactive monomer-functional group-free reactive monomer, functional group-containing reactive monomer-functional group-free reactive polymer, functional group-containing reactive polymer-functional group-nonfunctional Combinations such as a reactive polymer containing a functional group, a reactive polymer containing a functional group and a reactive monomer containing no functional group are also possible. Furthermore, it is preferable to use a polymerization agent, a polymerization initiator and a polymerization aid suitable for the polymerization of these reactive monomers and reactive polymers.

(Iii-2-3) Polymerization agent, polymerization initiator and polymerization aid In this specification, the polymerization agent refers to a catalyst used for polymerization, the polymerization aid refers to a substance that promotes polymerization, and the polymerization initiator refers to polymerization. This refers to a chain initiator in the reaction. These polymerization agents, polymerization initiators and polymerization accelerators are not particularly limited, and compounds usually used by those skilled in the art are used depending on the monomer to be polymerized. A polymerization agent, a polymerization initiator, and a polymerization assistant can be used alone or in combination, but it is generally preferable to use them in combination.

  These polymerizers, polymerization initiators, and polymerization aids are formed by directly bonding the functional groups in the resin particles or aggregate particles without the presence of reactive monomers or reactive polymers. In some cases, the gap can be bonded only at the surface. For example, when an epoxy group and a carboxyl group are present on the surface of the resin particle, when potassium persulfate is used as a polymerization initiator and heated, it is between the epoxy group of the resin particle A and the carboxyl group of another resin particle B. The resin particles A and the resin particles B are bonded on the surface by the dehydration reaction. In this way, the resin particles can be bonded only on the surface.

  Examples of the polymerization initiator include persulfates such as ammonium persulfate and potassium persulfate; hydrogen peroxide; azo initiators such as azobisisobutyronitrile; cumene hydroperoxide, t-butyl hydroperoxide, and the like. Organic peroxide: etc. are used. If necessary, a combination of persulfate or peroxide and a metal ion such as iron ion, a reducing agent such as sodium sulfoxylate, sodium pyrosulfite, or L-ascorbic acid may be used as a redox initiator. Good.

When a persulfate such as ammonium persulfate or potassium persulfate is used as a polymerization initiator, for example, sulfonate ion (—SO ₃ ⁻ ) or sulfate ester ion (—SO ₃ ⁻ ) is preferably used as the polymerization aid. . In this case, the surfactant having a sulfonate ion or a sulfate ester ion in the molecule functions as a polymerization aid.

  Examples of the surfactant having a sulfonate ion or a sulfate ester ion in the molecule include sodium dodecylbenzenesulfonate, sodium alkyldiphenyl ether disulfonate, sodium alkylnaphthalenesulfonate, sodium dioctylsulfosuccinate, sodium lauryl sulfate, polyoxy Examples include sodium ethylene alkyl ether sulfate.

(iv) Toner Production Method The toner of the present invention once forms resin particles and / or aggregate particles, and forms a network between these particles. Therefore, first, an emulsion of resin particles is produced. The resin particle emulsion is prepared by a method generally used by those skilled in the art, such as suspension polymerization and emulsion polymerization, using a monomer having a functional group and other monomers as necessary.

  What is necessary is just to determine the formation method of the network of the obtained resin particle according to the functional group in the resin particle. A network forming agent may be added to the dispersion medium (generally water) of the resin particle emulsion for reaction, or may be dispersed in advance in a dispersion medium for forming the resin particle emulsion.

  When the resin particles have only one kind of functional group, a crosslinking agent, a reactive monomer or a reactive polymer is added to, for example, a dispersion medium of the resin particle emulsion and reacted. When the resin particles have two types of functional groups, a cross-linking agent, a reactive monomer or a reactive polymer having two reactive groups capable of reacting with the two types of functional groups is used as a dispersion medium for the resin particle emulsion. It may be added to and reacted. However, the two types of functional groups in the resin particles are set to a combination that can react with each other (for example, a carboxyl group and a glycidyl group), and a polymerization agent, a polymerization initiator, and a polymerization aid are added to the dispersion medium of the resin particle emulsion. It may be added and heated and dehydrated. A resin particle emulsion having only carboxyl groups and a resin particle emulsion having only epoxy groups may be mixed, and a polymerization agent, a polymerization initiator, and a polymerization aid may be added to the dispersion medium, followed by heating and dehydration. Such a reaction forms a network between the resin particles.

  Hereinafter, a specific method for producing a toner will be described with reference to the case of a styrene-methacrylate-acrylic acid copolymer resin, but the present invention is not limited to this, and in the production of other resins. Are used similarly.

(Iv-1) Preparation of resin particles (Preparation of resin particles-1)
A monomer mixture containing a polymerization initiator, styrene, methacrylate, acrylic acid, and a colorant is added dropwise to an aqueous solution such as a surfactant and an emulsifier with stirring to prepare an emulsion containing polymer particles. If necessary, a monomer mixture of methacrylate and acrylic acid may be added dropwise to the emulsion with stirring. The resin particles in the resulting colored emulsion A have a carboxyl group.

(Preparation of resin particles-2)
A monomer mixture containing a polymerization initiator, styrene, methacrylate, glycidyl methacrylate and a colorant is added dropwise to an aqueous solution of a surfactant, an emulsifier and the like with stirring to prepare an emulsion containing polymer particles. If necessary, a monomer mixture of methacrylate and glycidyl methacrylate may be further added dropwise to the emulsion with stirring. The resin particles in the resulting colored emulsion B have an epoxy group.

(Iv-2) Network formation (Network formation-1)
When a crosslinking agent (for example, ethylene glycol diglycidyl ether) is added to the colored emulsion A (carboxyl group-containing) obtained in Preparation-1 of the resin particles and dried, the epoxy groups in the crosslinking agent and the carboxyls in the resin particles A dehydration reaction occurs between the groups and the resin particles are cross-linked. Thereby, aggregate particles composed of aggregates of resin particles are obtained. In addition, it is thought that the particles 12 and 14 as shown in FIG. 1 are formed by heating. The same applies to the following examples.

(Network formation-2)
Colored emulsion A (carboxyl group-containing) obtained in resin particle preparation-1 and colored emulsion B (epoxy group-containing) obtained in resin particle preparation-2 are charged into a dispersion medium and mixed. At this time, potassium persulfate as a polymerization initiator and sodium dodecylbenzenesulfonate as a polymerization aid are dissolved in the dispersion medium. By heating the resin particle emulsion obtained by mixing, a carboxyl group and an epoxy group cause a dehydration reaction, the resin particles are bonded to each other on the surface, and a network is formed, which is an aggregate of resin particles. Aggregate particles are obtained. In the above step, instead of dispersing colored emulsion A and colored emulsion B, when a dispersion medium in which a polymerization initiator and a polymerization assistant are dissolved in advance is used for each of colored emulsion A and colored emulsion B, colored emulsion A and The colored emulsion B may be mixed as it is and heated to form a network.

(Iv-3) Preparation of Toner Aggregate particles, which are aggregates of resin particles obtained in the network formation step, are dried to form toner particles. As a drying method, methods such as oven drying, fluidized drying, airflow drying, and spray drying are used. As the spray drying method, a spray drying method, a piezoelectric discharge method, a bubble jet (registered trademark) discharge method, or the like is used. An external additive is added to the obtained toner particles to prepare a toner.

(Iv-3-1) Toner Particles The weight average molecular weight of the toner particles used in the present invention is not particularly limited. The molecular weight is measured, for example, by gel permeation chromatography (GPC). Specifically, 5 mg of toner resin is dissolved in 5 g of THF, and a GPC sample is prepared through a membrane filter having a pore size of 0.2 μm in order to remove THF-insoluble matter and impurities. The sample thus prepared (THF soluble content) is measured under the following conditions using GPC.
Column: “Shodex (GPC) KF806M + KF802.5” manufactured by Showa Denko K.K.
Column temperature: 30 ° C
Solvent: THF (tetrahydrofuran)
Flow rate: 1.0 ml / min.
Detector: UV detector (detection wavelength 254 nm)
Standard sample: Monodisperse polystyrene standard sample (mass average molecular weight 580 to 3.9 million).

When fixing the toner in image formation by the thermal fixing method, the flow softening point (Tf _1/2 ) of the toner particles is preferably low. Tf _1/2 is, for example, preferably 85 to 150 ° C, more preferably 90 to 130 ° C, and further preferably 100 to 120 ° C. The glass transition temperature (Tg) of the toner particles is preferably 40 to 150 ° C, and more preferably 50 to 90 ° C.

In addition, the measuring method of the flow softening point (Tf1 _{/ 2} ) of resin is as follows. A cylindrical sample is prepared by compressing and molding 1.0 g of resin into a pellet and matching the inner diameter of the cylinder of the measuring instrument. This sample is measured under the following conditions using “Flow Tester CFT-500D” manufactured by Shimadzu Corporation. Temperature rising rate 5 ° C./min; cylinder pressure 195 N; die hole diameter 1.0 mm; die length 1.0 mm; Tf _1/2 measurement method: 1/2 method.

  The measuring method of the glass transition temperature (Tg: ° C.) of the resin is as follows. 10 mg of resin is packed in an aluminum cell, and measured using a “DSC220C / EXTRA6000 PC station” manufactured by Seiko Instruments Inc. under the following conditions. Measurement start temperature: 20 ° C., measurement end temperature: 200 ° C .; temperature is increased at a temperature increase rate of 10 ° C./min, and then the temperature is decreased to 20 ° C. at a temperature decrease rate of 10 ° C./min. The temperature at the position where the endotherm corresponding to the glass transition point at this time is generated (shoulder position of the endothermic curve) is defined as the glass transition point.

(Iv-3-2) Internal Additive The toner particles preferably contain an internal additive such as a colorant, a charge control agent, and a release agent in advance. Therefore, it is preferable to add an internal additive such as a colorant when preparing the toner particles. Although there is no restriction | limiting in a coloring agent, As shown below, an organic pigment, an inorganic pigment, and dye can be used. Among organic and inorganic pigments, carbon black, copper oxide, iron tetroxide, manganese dioxide, aniline black, activated carbon, etc. are used as the black pigment.

  As the yellow colorant used in the present invention, compounds typified by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, allylamide compounds and the like are used. Specifically, for example, C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 97, 109, 110, 111, 120, 127, 128, 129, 147, 168, 174, 176, 180, 181 and 191 are preferably used.

  Examples of magenta colorants used in the present invention include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. Are used. Specifically, for example, C.I. I. Pigment Red 2, 3, 5, 6, 7, 23, 48: 2, 48: 3, 48: 4, 57: 1, 81: 1, 122, 144, 146, 166, 169, 177, 184, 185, It is particularly preferable to use 202, 206, 220, 221, 254, 269 or the like.

  As the cyan colorant used in the present invention, compounds represented by copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, basic dye lake compounds and the like are used. Specifically, for example, C.I. I. Pigment Blue 1, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62, 66 and the like are particularly suitable.

  These colorants may be used alone or in combination of two or more, but it is desirable to use 1 to 20 parts by weight, preferably 2 to 10 parts by weight, based on 100 parts by weight of the toner particles. When the amount is more than 20 parts by mass, the toner fixing property and transparency are deteriorated. On the other hand, when the amount is less than 1 part by mass, a desired image density may not be obtained.

(Iv-3-3) External additive To the toner particles containing the internal additive, an external additive is added for the purpose of improving the chargeability and fluidity of the toner. Examples of the external additive include negatively chargeable silica fine particles, titanium oxide, metal soap, and positively chargeable silica fine particles.

  As the negatively chargeable silica fine particles, generally negatively chargeable silica fine particles having an average particle size of 4 to 120 nm, preferably 5 to 50 nm, and more preferably 6 to 40 nm are used. The negatively chargeable silica fine particles are preferably hydrophobized from the viewpoint of improving the fluidity and chargeability of the toner. Examples of the hydrophobic negatively chargeable silica fine particles include commercially available RX200 (average particle size of 12 nm), RX50 (average particle size of 40 nm) manufactured by Nippon Aerosil Co., Ltd., TG811F, TG810G, and TG308F manufactured by Cabot Corporation. Is used. A combination of negatively chargeable silica fine particles having different average particle diameters may be used.

  The addition amount of the negatively chargeable silica fine particles is generally 0.5 to 2.0 parts by mass, preferably 0.7 to 1.5 parts by mass with respect to 100 parts by mass of the toner particles. In the present specification, the average particle diameter of fine particles means a volume average particle diameter unless otherwise specified.

  The titanium oxide fine particles are used as necessary for adjusting the charge of the toner. Although there is no restriction | limiting in particular in the magnitude | size of a titanium oxide microparticle, It is preferable that a particle size or the magnitude | size of a major axis is a magnitude | size of 10-30 nm. The titanium oxide fine particles are added in an amount of 0.2 to 2.0 parts by weight, preferably 0.3 to 1.5 parts by weight, based on 100 parts by weight of the toner particles. The addition of the titanium oxide fine particles and the positively chargeable silica fine particles in a mass ratio of 1: 3 to 3: 1 can adjust the charge without causing an extreme decrease in the electric resistance of the toner. In terms, it is preferable.

  The surface of the titanium oxide fine particles is hydrophobic in order to reduce the change in chargeability with respect to the change in the external environment of the toner (that is, maintain stable chargeability) and improve the fluidity of the toner. ,preferable. As the hydrophobic titanium oxide fine particles, STT-30S manufactured by Titanium Industry Co., Ltd. is used.

  Metal soap is added as necessary for the purpose of improving the fluidity of the toner, improving the binding property of the external additive, and preventing toner aggregation. For example, magnesium stearate, calcium stearate, zinc stearate and the like can be mentioned. The metal soap preferably has a volume average particle diameter or major axis diameter of 0.5 to 10 μm, and more preferably 1 to 5 μm. The metal soap is added in an amount of 0.1 to 1.0 part by weight, preferably 0.1 to 0.5 part by weight, based on 100 parts by weight of the toner particles.

  The positively chargeable silica fine particles are used as necessary for adjusting the charge of the toner. The positively chargeable silica fine particles used in the present invention are not particularly limited. The volume average particle diameter of the positively chargeable silica fine particles is preferably 10 to 50 nm, more preferably 15 to 40 nm in consideration of fluidity and the like. The positively chargeable silica fine particles are preferably hydrophobized from the viewpoint of maintaining chargeability and improving fluidity. As the hydrophobic positively chargeable silica fine particles, commercially available NA50H manufactured by Nippon Aerosil Co., Ltd., TG820F manufactured by Cabot Co., Ltd., etc. are used. The positively chargeable silica fine particles are added in an amount of 0.1 to 1.0 parts by weight, preferably 0.2 to 0.8 parts by weight, based on 100 parts by weight of the toner particles, if necessary.

  In addition, for example, external additives commonly used by those skilled in the art other than those described above, such as inorganic fine particles added for the purpose of controlling chargeability and improving fluidity, are also used.

  The external addition process is performed by adding a predetermined amount of the above external additive to the toner particles and performing, for example, a stirring / mixing process using a Henschel mixer.

  The toner of the present invention can be used in any type of image forming apparatus. An image forming apparatus using a one-component toner or an image forming apparatus using a two-component toner may be used. Further, it may be a contact developing type image forming apparatus or a non-contact type image forming apparatus. A one-component contact type image forming apparatus that can use the toner of the present invention is described in detail in, for example, Japanese Patent Application Laid-Open No. 2002-202622. The image forming apparatus of the present invention includes a latent image carrier on which an electrostatic latent image typified by a photoreceptor is formed; toner is applied to the latent image carrier to develop the electrostatic latent image on the latent image carrier. At least a developing device having a toner carrying member typified by a developing roll to be conveyed; and a toner regulating member for regulating the amount of toner carried to the latent image carrying member by the toner carrying member. The toner of the present invention is accommodated in a toner accommodating portion, conveyed from the toner accommodating portion to a developing roll (toner carrier), and supplied to the photosensitive member (latent image carrier) via the developing roll (toner carrier). And transferred to form an image. The toner regulating member adjusts the toner supply amount so that excessive supply from the developing roll (toner carrier) to the photosensitive member (latent image carrier) is not performed.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated, this invention is not restrict | limited to this Example.
(A) Preparation of colored emulsion 1 1000 parts by weight of distilled water and 10 parts by mass of polyoxyethylene nonylphenol ether (HLB = 14) are added to a reaction vessel (capacity: 3 liters; with stirrer, reflux condenser, dropping device and thermometer). And 10 parts by mass of sodium lauryl sulfate were charged and stirred at a temperature of 30 to 40 ° C. and 40 to 60 rpm in a nitrogen atmosphere to dissolve the contents and heated to 85 ° C.

  While maintaining the temperature of the contents at 85 ° C., 3 parts by mass of potassium persulfate was added, 260 parts by mass of styrene, 270 parts by mass of n-butyl acrylate and 5 parts by mass of sodium acrylate, CI Pigment Blue 15: 334 mass A soft monomer mixture consisting of parts was dropped over 2 hours and then polymerized by maintaining at 85 ° C. for 1 hour to prepare an emulsion containing soft polymer particles.

  Next, a hard monomer mixture composed of 290 parts by weight of methyl methacrylate and 5 parts by weight of sodium acrylate was dropped into the emulsion over 2 hours, and then kept at 85 ° C. for 1 hour to prepare an emulsion. Then, it cooled to normal temperature, 25% ammonia water was added as a neutralizing agent, pH was adjusted to 8-9, and the colored emulsion 1 was obtained. The ratio of the soft monomer mixture to the hard monomer mixture was 64:36 (% by mass).

  The solid content concentration of the colored emulsion 1 was 46% by mass and the average particle size was 130 nm.

(B) Network formation To 100 parts by mass of the obtained colored emulsion 1, 8 parts by mass of ethylene glycol diglycidyl ether was added and spray-dried at 100 ° C. to obtain toner particles 1.

(C) Preparation of toner 1 and properties of toner 1 The external additive was applied to the toner particle 1 by mixing the external additive using a 20 L type Henschel mixer. As external additives, hydrophobic negatively chargeable small particle size silica RX200 (Nippon Aerosil, average particle size: 12 nm): 1 part by mass, hydrophobic negatively chargeable large particle size silica RX50 (Nippon Aerosil, average particle) Diameter: 40 nm): 0.5 part by mass and titanium oxide STT-30S (average particle diameter: 20 nm): 0.5 part by mass were used. Note that negatively chargeable silica (negatively chargeable small particle size silica, negatively chargeable large particle size silica) is hydrophobized with hexamethyldisilazane. Thus, toner 1 was obtained.

Particle size of the obtained toner 1 D ₅₀ was measured by Multisizer III (manufactured by Beckman Coulter, Inc.) was 5.2 .mu.m. The water content was 0.2% by the Karl Fischer method (manufactured by Hiranuma Sangyo). The molecular weight (mass average molecular weight of the resin constituting the toner, hereinafter the same) was 2.3 × 10 ⁵ , Tg was 2 ° C. and 120 ° C., and Tf _1/2 was 120 ° C.

Example 2 Preparation of Toner 2 (a) Preparation of Colored Resin Dispersion 1-1 Polyester resin (Tg: 50 ° C., Tf _1/2 : 85 ° C., acid value: 8, Mw: 5000) 50 parts by mass C. I. Pigment Blue 15: 3 50 parts by mass was dispersed in 100 parts by mass of ethyl acetate. This dispersion was introduced into a sand mill disperser containing glass beads. The periphery of the dispersion vessel was cooled to 25 ° C., and dispersed for 3 hours with stirring. Finally, ethyl acetate was added as an evaporation component to prepare a colored resin dispersion 1-1 having a pigment concentration of 10% by mass.

(B) Preparation of colored resin dispersion 1-2 Polyester resin (Tg: 50 ° C., Tf _1/2 : 85 ° C., acid value: 8, Mw: 5000) 87 parts by mass, the colored resin prepared in (a) above 50 parts by mass of dispersion 1-1 (pigment concentration: 10% by mass) and 32 parts by mass of ethyl acetate were mixed to obtain a mixed solution in which the polyester resin was sufficiently dissolved. This mixed solution was put into a homomixer and stirred for 2 minutes at a speed of 15000 revolutions per minute to prepare a uniform oil phase. To this oil phase, 2.7 parts by mass of triethylamine was added, and then 1000 parts by mass of ion-exchanged water was added, followed by stirring, and ethyl acetate was distilled off under reduced pressure at 30 ° C. and 20-30 mmHg. Thereafter, centrifugal sedimentation was repeated three times to exchange the supernatant, and a colored resin dispersion 1-2 of a polyester resin having a solid content of 30% by mass was obtained. The average particle size of the fine dispersion obtained was 0.5 μm.

(C) Preparation of colored resin dispersion 2-1 50 parts by mass of polyester resin (Tg: 65 ° C., Tf _1/2 : 102 ° C., acid value: 25, Mw: 9000) and C.I. I. Pigment Blue 15: 3 50 parts by mass was dispersed in 100 parts by mass of ethyl acetate. This dispersion was introduced into a sand mill disperser containing glass beads. The periphery of the dispersion vessel was cooled to 25 ° C., dispersed for 3 hours with stirring, and finally ethyl acetate was added to prepare a colored resin dispersion 2-1 having a pigment concentration of 10% by mass.

(D) Preparation of colored resin dispersion 2-2 Polyester resin (Tg: 65 ° C., Tf _1/2 : 102 ° C., acid value: 25, Mw: 9000) 87 parts by mass, the colored resin prepared in (c) above 50 parts by mass of dispersion 2-1 (pigment concentration: 10% by mass) and 32 parts by mass of ethyl acetate were mixed to obtain a mixed solution in which the polyester resin was sufficiently dissolved. This mixed solution was put into a homomixer and stirred for 2 minutes at a speed of 15000 revolutions per minute to prepare a uniform oil phase. To this oil phase, 2.7 parts by mass of triethylamine was added, and then 1000 parts by mass of ion-exchanged water was added, followed by stirring, and ethyl acetate was distilled off under reduced pressure at 30 ° C. and 20-30 mmHg. Thereafter, centrifugal sedimentation was repeated three times to exchange the supernatant, and a colored resin dispersion 2-2 of a polyester resin having a solid content of 30% by mass was obtained. The average particle size of the fine dispersion obtained was 0.48 μm.

(E) Formation of network Into a 5-liter flask equipped with a thermometer, a condenser and a stirrer, 1000 parts by mass of the colored resin dispersion 1-2 prepared in (b) above and 55 parts by mass of dimethylaminoethyl propionate were added. As a result, a solution having a pH of 10.2 was obtained. The temperature of this solution was raised to 70 ° C., and stirring was continued for 240 minutes to grow fine dispersion particles. The pH of the solution after the particle growth was lowered to 7.5. When the obtained particles were measured using Multisizer III (manufactured by Coulter), the D ₅₀ of the grown particles was 4.5 μm. Next, 150 g of the colored resin dispersion 2-2 prepared in (d) above and 10 g of ethylene glycol diglycidyl ether as a network forming agent are added to 100 g of the particles, and the mixture is stirred at 60 ° C. for 120 minutes. Particles 2 for use were obtained.

(F) Preparation of toner 2 and properties of toner 2 The obtained colored resin dispersion 2-2 was dehydrated and filtered with a suction funnel and then pulverized by freeze-drying to obtain toner particles 2. External addition of the external additive to the toner particles 2 was performed in the same manner as in Example 1 to obtain a toner 2. Particle size of the obtained toner 2 was measured by Multisizer III a, D ₅₀ was 4.8 .mu.m. The water content was 2.3% by Karl Fischer method, the molecular weight was 7.0 × 10 ³ , Tg was 64 ° C., and Tf _1/2 was 102 ° C.

Comparative Example 1 Preparation of Toner 3 (a) Preparation of Toner Particle 3 100 parts by mass of the colored emulsion 1 obtained in Example 1 was placed in a round stainless steel flask and stirred with a heating oil bath. Heated to 50 ° C. After adding 20 parts by mass of ethanol and keeping at 50 ° C. for 1 hour, it was heated to 100 ° C. and kept for 4 hours. After cooling, it was filtered off, washed with ion exchange water twice, and vacuum dried to obtain toner particles 3. The toner particles 3 are simply agglomerated resin particles.

(B) Preparation of toner 3 and properties of toner 3 External addition of the external additive to the toner particles 3 was performed in the same manner as in Example 1 to obtain toner 3. D ₅₀ where the particle size was measured by Multisizer III of obtained toner 3 was 5.0 .mu.m. The moisture content was 0.2% by Karl Fischer method, the molecular weight was 1.5 × 10 ⁵ , Tg was 2 ° C. and 120 ° C., and Tf _1/2 was 105 ° C.

(Comparative Example 2) Preparation of Toner 4 (a) Preparation of Toner Particle 4 Same as Example 2 except that in Example 2 (e), ethylene glycol diglycidyl ether as a network forming agent was not added. Thus, toner particles 4 were prepared. The toner particles 4 are obtained by aggregating the resin particles in the colored resin dispersion 2-2 on the core particles with the resin particles in the colored resin dispersion 1-2 in (b) as a core.

(B) Preparation of toner 4 and properties of toner 4 External addition of the external additive to the toner particles 4 was carried out in the same manner as in Example 1 to obtain toner 4. Particle size of the obtained toner 4 was measured by Multisizer III a, D ₅₀ was 5.0 .mu.m. The water content was 0.3% by Karl Fischer method, the molecular weight was 6.0 × 10 ³ , Tg was 62 ° C., and Tf _1/2 was 98 ° C.

(Evaluation of toner)
Each toner prepared above was tested for fixing and durability, and each toner was evaluated.

(Fixability test)
A color laser printer KL-2010 manufactured by Konica Corporation was modified and used to fix the image. The fixing device (fixing unit) is a heat roller fixing device including a heating roller and a pressure roller. However, this fixing device (fixing unit) was removed and modified so that it can be driven independently by an external driving device and the fixing nip passage time can be adjusted. The roller (fixing roller) on the side in contact with the toner image on the paper was modified so that the temperature could be controlled from 100 ° C. to 200 ° C. Using this fixing device, the image for fixing property evaluation was passed so that the heating roller side would be an unfixed toner adhesion surface, and fixed under the condition of a nip passage time of 50 msec. The image for fixing evaluation was prepared as follows using a color laser printer LP-3000C manufactured by Seiko Epson Corporation. First, J paper manufactured by Fuji Xerox Office Supply Co. is used as an evaluation paper, and a so-called solid image is formed by uniformly adhering the prepared toner on the paper, and the toner adhesion amount in the solid image becomes 0.4 mg / cm ^2. The image forming conditions were adjusted as described above, and then a solid image was formed in a 20 mm square area at a position 10 mm from the leading edge of the paper, and this image was used as an image for fixing property evaluation.

  While changing the surface temperature of the fixing roller step by step, pass an unfixed image sample and check whether or not (part of the image) has transferred to the fixing roller after passing through the fixing roller. Judgment was made visually. Those with a shift to paper were marked with an offset, and those without a shift were marked with no offset. Then, the presence / absence of offset at each temperature is checked, the temperature region without offset is set as a region without offset, and the case where the temperature width of the region without offset is 60 ° C. or more is passed, the temperature width of the region without offset is 60 ° C. The case where it was less than that was regarded as rejected, and in Table 1, it was represented by ○ and ×, respectively.

(Durability test)
For each toner, a color laser printer LP-3000C manufactured by Seiko Epson Corporation was used, and printing durability with 5% image was measured. The number of printable sheets was measured, and the case where more than 6000 sheets could be passed was accepted and the case where less than 6000 sheets was rejected. The results are shown in Table 1.

  Although the fixing property test was performed only up to 200 ° C., as shown in the results of Table 1, the toner 1 and the toner 2 of the present invention were not found to have an offset at 140 ° C. to 200 ° C., and offset at least 60 ° C. or more. Since it has a good region, it can be seen that the fixability is good and the number of printable sheets is 6000 or more. On the other hand, the toners of Comparative Examples 3 and 4 (Toner 3 and Toner 4 respectively) have inferior fixability with good offset regions of 40 ° C. and 50 ° C., respectively. It can be seen that the number of sheets is 5,000 and 5000, which is significantly inferior to the toner of the present invention. This is because although the toner of the present invention is a kind of aggregated particles, the resin particles constituting the toner are bonded to each other so as to have a boundary surface on the surface, and the network forming agent is localized on the boundary surface. In addition, this boundary surface is higher in strength than other resin particle portions, and the resin particle mass having these boundary surfaces forms a network, so that it is resistant to external stress. Compared to conventional mere aggregated particles, it has excellent durability during use, and the resin particles are bonded only at the boundary surface, indicating that the melting characteristics of the toner are not impaired. ing.

(Confirmation of bond between particles)
The toners of Examples 1 and 2 prepared above (Toner 1 and Toner 2 respectively) and the toners of Comparative Examples 1 and 2 (Toner 3 and Toner 4 respectively) were made 0.5 mm with an ultramicrotome using an embedding resin. Cut and observed with an intermolecular force probe microscope. In the toner 1 and toner 2 of the example, the greatest elasticity was observed at the boundary surface between the resin particles and the resin particles in the resin particle lump. On the other hand, in the toner 3 and the toner 4 of the comparative example, the greatest elasticity was observed in the portion near the outside in the resin particle. In the toner of the present invention, since the greatest elasticity was observed at the interface between the resin particles, the network forming agent was localized at the interface between the resin particles, and the resin particles were firmly bonded at the interface. You can see that In contrast, in the toner of the comparative example, it can be seen that the resin particles are merely aggregated. FIG. 2 is an SEM photograph of toner 1. Considering this result and the fact that the greatest elasticity was obtained between the resin particles, it is understood that the network forming agent is localized at the boundary surface of the resin particles, and the strength of the toner is improved.

  From the above results, the toner of the present invention is a toner with high sphericity in which each resin particle is bonded only on the surface of the resin particle, and is excellent in fluidity. And it is understood that it is excellent in durability and fixability compared with conventional simple aggregated particles, and the manufacturing method is simple.

  The toner of the present invention is easy to manufacture, has high fluidity due to high sphericity of toner particles, and is excellent in durability and fixability, and is therefore widely used as a toner for electrophotography.

FIG. 3 is a schematic diagram showing a structure of a toner of the present invention. 3 is an SEM photograph of the toner of the present invention.

Explanation of symbols

11 Resin Particles 12, 13, 14, 15 Resin Particle Mass 16 Network 17 Interface

Claims (5)

  A toner containing aggregate particles having a resin particle mass, wherein the resin particle mass has a shape in which the resin particles melt or contact each other with a boundary surface, and the aggregate particle is a network forming agent A toner having a network structure according to claim 1, wherein the interface is bound via a network-forming agent, and the network-forming agent is localized at the interface.   The toner according to claim 1, wherein the network forming agent is a water-soluble crosslinking agent.   The toner of claim 2, wherein the crosslink is formed by dehydration.   The toner according to claim 2, wherein the crosslinking agent has a functional group capable of reacting with a carboxyl group.   The toner according to claim 1, wherein the network forming agent is at least one selected from the group consisting of a reactive monomer, a reactive polymer, a polymerizing agent, a polymerization aid, and a polymerization initiator.

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