JP4049068B2 - Toner for electrostatic image development - Google Patents

Description

  The present invention relates to an electrostatic charge image developing toner used in electrophotography.

  At present, low temperature fixing designs targeting energy-saving fixing of toner images are frequently carried out by various companies, and many proposals for new technologies have been made, but they have the following drawbacks.

  There are two main approaches to achieving low-temperature toner fixing. The first is to lower the viscosity of the resin, and the second is to lower the melting point of the wax contained and increase the amount added. However, what is common to these prescriptions is that the viscosity of the toner is greatly reduced. For this reason, problems such as a decrease in the viscosity of the resin, a decrease in heat storage stability and blocking resistance due to the lower melting point of the wax, and a decrease in charging characteristics and cleaning properties due to an increase in the amount of wax are caused.

  These problems can be solved to some extent by improving the toner configuration to a capsule structure, a core-shell structure, or the like. For example, in a styrene-acrylic copolymer composition that can be produced by an emulsion polymerization method, the viscosity of the toner outer shell layer is improved by reducing the molecular weight of the inner shell layer and increasing the molecular weight of the outer shell layer. Storage properties and blocking resistance can be improved. However, even when such a toner configuration is used, the solution method still depends on the viscosity of the toner, and the resin is designed with a balance between the viscous component and the elastic component. As a result, the elastic function is lowered, and the fixing separation performance and anti-offset performance at the time of oilless fixing are surely lowered.

  In addition, when the control is attempted with the melting point and the addition amount of the wax without touching the viscoelastic function of the resin, the viscoelastic function as a toner changes in the same manner as the resin, so there is a problem in controlling the viscoelastic function of the resin. Will occur.

  Therefore, in the conventional toner, in order to achieve low-temperature fixing, other characteristics (fixing separation performance and anti-offset performance) must be sacrificed.

  An object of the present invention is to provide a toner for developing an electrostatic image having excellent fixing properties such as low-temperature fixing property, fixing separation property and offset resistance, heat-resistant storage property and charging property.

The present invention is an electrostatic charge image developing toner containing toner particles obtained by agglomerating / fusing resin particles obtained by polymerizing a polymerizable monomer containing at least an amino group-containing monomer and colorant particles in an aqueous medium. Te, Ri amine value 0.05~5KOHmg / g der toner, resin particles sequentially in the center, has a three-layer structure comprising an intermediate layer and an outer layer laminated, the resin is configured monomer as an outer layer The present invention relates to a toner for developing an electrostatic image characterized by containing an acid monomer .

  The toner of the present invention achieves both excellent low-temperature fixability and excellent fixing separation and offset resistance. Furthermore, it is excellent in heat-resistant storage properties and charging properties.

  The toner for developing an electrostatic charge image of the present invention contains toner particles obtained by aggregating / fusing at least resin particles and colorant particles in an aqueous medium.

In the present specification, “aggregation” is used in a concept intended to simply attach at least a plurality of resin particles. By “aggregation”, so-called hetero-aggregated particles (group) are formed in which the constituent particles are in contact with each other, but no bonding due to melting of resin particles or the like is formed. A group of particles formed by such “aggregation” is referred to as “aggregated particles”.
"Fusion" is used in a concept that is intended to form a bond as a unit of use and handling by forming a bond due to melting of resin particles etc. in at least a part of the interface of the individual constituent particles in the aggregated particles And The particle group that has undergone such “fusion” is referred to as “fused particles”.
“Aggregation / fusion” refers to an action in which aggregation and fusion occur simultaneously or in stages, or an action in which aggregation and fusion occur simultaneously or in stages.

  In the present invention, by containing an amino group-containing monomer as a constituent monomer of the resin particles, a predetermined amine value of the toner is achieved, and as a result, both excellent low-temperature fixability and excellent fixing separation and offset resistance are achieved. Achieve effectively. That is, in the present invention, the resin can be used without greatly changing the viscoelasticity of the toner by lowering the viscosity of the resin more than necessary, lowering the melting point of the wax, or increasing the wax content more than necessary. Low-temperature fixability is improved by incorporating a monomer containing amino group as a constituent monomer of the particles to achieve the prescribed amine value of the toner, so excellent fixing separation and offset resistance even during oilless fixing Can be secured. Although details of the mechanism for improving the low-temperature fixability due to the inclusion of the amino group-containing monomer and the toner having a predetermined amine value are not clear, the amino group between the toner and the recording medium (paper), particularly in the toner This is considered to be due to the fact that a hydrogen bond is generated between the amino group derived from the containing monomer and the hydroxyl group on the paper surface, thereby improving the affinity. In addition, by setting the amine value within a predetermined range, the affinity between the binder resin and the colorant and the wax is improved, and the dispersibility of the colorant and the wax in the toner particles is improved. Therefore, it is possible to effectively improve fixing properties such as low-temperature fixing property, fixing separation property and offset resistance while suppressing the influence on the charging property and heat-resistant storage property of the toner, and further increase the image density effectively. Can do. Further, even if an amino group-containing monomer is contained, the moisture absorption resistance of the toner is hardly lowered, so that a good image can be stably formed even by an environmental change. It is conceivable to use a carboxyl group-containing monomer instead of an amino group-containing monomer for the purpose of improving the affinity between the toner and paper, but if a carboxyl group-containing monomer is contained, the low-temperature fixability is not improved so much. In addition, the moisture absorption resistance of the toner decreases, and fogging occurs particularly in a high humidity environment.

  The amine value of the toner of the present invention is 0.05 to 5 KOH mg / g, preferably 0.5 to 4.5 KOH mg / g, more preferably 1 to 4.0 KOH mg / g. If the amine value is too small, the effect of improving the affinity between the toner and paper is too small, so that the low-temperature fixability cannot be effectively improved. If the amine value is too large, the chargeability deteriorates when the toner is used as a negatively chargeable toner, so that the use of the toner is limited; the heat-resistant storage property tends to be lowered; The particle size distribution tends to be difficult to be sharp because the properties are not stable.

  In the present specification, the amine value is a value measured by the following method. That is, about 1 g of a sample is weighed, 20 ml of toluene is added and dissolved, 20 ml of isopropyl alcohol and bromophenol blue solution are added, titrated with 1/10 N isopropyl alcohol solution, and the titration amount to the end point is read. From this titration amount, the amine value is calculated by the following formula. In the following formula, f is a factor (titer) of 1 / 10N isopropyl alcohol solution.

  In the present invention, by further adjusting the acid value of the toner to 1 to 30 KOH mg / g, preferably 0.1 to 20 KOH mg / g, more preferably 0.1 to 10 KOH mg / g, the colorant and wax in the toner particles Can be further improved. As a result, the fixing property can be improved more effectively, and the image density can be increased more effectively.

The total nitrogen amount of the toner of the present invention is usually 0.05 to 0.5%, preferably 0.1 to 0.45%.
The total amount of nitrogen in the toner is the weight ratio of the total nitrogen atoms present in the toner to the total amount of toner. The total amount of nitrogen in the toner can be measured with a trace carbon analyzer (TN-10; manufactured by Mitsubishi Chemical Corporation) after heating the toner at high temperature in an oxygen atmosphere and thermally decomposing it into NOX (gaseous nitrogen oxide). . The total amount of nitrogen in the toner does not have to be measured by the device. Any device that can measure the total nitrogen amount of toner based on the same principle and principle as the above device may be used.

  The resin particles constituting the toner particles of the present invention are made of a polymer resin of an amino group-containing monomer and another polymerizable monomer.

  The amino group-containing monomer is a monomer containing an amino group and capable of radical polymerization, and examples thereof include acrylates, methacrylates, styrenes, allyls, vinyls and dienes containing amino groups. In the present invention, the amino group is an unsubstituted amino group or one or two hydrogen atoms of the amino group, respectively, other substituents such as a methyl group, an ethyl group, a butyl group, a cyclohexyl group, a phenyl group, a benzyl group. It may be a substituted amino group substituted with a group or the like, and may further be a cyclic amino group. Examples of the cyclic amino group include a pyridyl group, a quinolyl group, a carbazolyl group, a pyrrolyl group, an imidazolyl group, a pyrazolyl group, a piperidyl group, a pyrrolidone ring-containing group, and a lactam ring-containing group.

  Specific examples of such amino group-containing monomers include, for example, N-methylaminoethyl acrylate, N-ethylaminoethyl acrylate, N, N-dimethylaminoethyl acrylate, N, N-diethylaminoethyl acrylate, N, N-dibutyl Substituted amino group-containing acrylates such as aminoethyl acrylate and N, N-diethylaminopropyl acrylate, aminoethyl methacrylate, N, N-dimethylaminoethyl methacrylate, N, N-diethylaminoethyl methacrylate, N-methylaminoethyl methacrylate, N- Ethylaminoethyl methacrylate, 2-N, N-dicyclohexylaminoethyl methacrylate, N, N-dibutylaminoethyl methacrylate, 2-phenylaminoethyl methacrylate, 2-benzylaminoethyl methacrylate Substituted amino group-containing methacrylates such as aminostyrene, dimethylaminoethylstyrene, N-methylaminoethylstyrene, dimethylaminoethoxystyrene and other aminostyrenes, allylamine, allylmethylamine and other allylamines, 2-vinylpyridine Such as 3-vinylpyridine, 4-vinylpyridine, 2-methyl-5-vinylpyridine, 2-methyl-6-vinylpyridine, 5-ethyl-2-methylpyridine, 2,6-dimethyl-5-vinylpyridine, etc. Vinyl pyridines, vinyl piperidines such as 2-vinyl piperidine, vinyl pyrroles such as 2-vinyl pyrrole, vinyl quinolines such as 4-vinyl quinoline, other vinyl carbazoles, vinyl imidazoles, vinyl pyrazolines, allyl quinolines , Vinylamines, N-vinylpyrrolidone, etc. Examples thereof include vinyl lactams such as nylpyrrolidones, N-vinyl lactam, and N-vinyl caprolactam. Of these, substituted amino group-containing acrylates and substituted amino group-containing methacrylates are preferred.

  The content of the amino group-containing monomer is not particularly limited as long as the obtained toner has a predetermined amine value, but is usually 0.5 to 4.5% by weight, preferably 0, based on the total monomers constituting the resin particles. 0.5 to 3% by weight.

  The other polymerizable monomer (hereinafter simply referred to as “polymerizable monomer”) is not particularly limited as long as it is a monomer capable of forming an addition polymerization type resin used as a binder resin for toner. For example, styrene, o-methyl Styrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, pn-butylstyrene, p-tert-butylstyrene, p-nonylstyrene, p- Styrenes such as phenylstyrene, methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, hydroxyethyl acrylate, 2-ethylhexyl acrylate, and other acrylic esters, methyl methacrylate , Ethyl methacrylate, propyl methacrylate, methacrylic acid n Butyl, isobutyl methacrylate, hydroxyethyl methacrylate, methacrylic acid esters such as 2-ethylhexyl methacrylate, cyclohexene, acrylonitrile, methacrylonitrile, vinyl chloride, vinyl acetate and the like.

  An acid monomer having an acidic polar group can also be used as the polymerizable monomer. Examples of the acid monomer include monomers having a carboxyl group such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid and cinnamic acid, and monomers having a sulfonic acid group such as sulfonated styrene.

  In the present invention, substituted amino group-containing acrylates (and / or substituted amino group-containing methacrylates), styrene, and acrylic acid esters (and / or methacrylic acid esters) are used as polymerizable monomers, and acrylic acid and methacrylic acid are used as acid monomers. Are preferably used.

  Moreover, a crosslinking monomer can also be used as the polymerizable monomer. Examples of cross-linkable monomers include divinylbenzene, divinylnaphthalene, divinyl ether, diethylene glycol dimethacrylate, ethylene glycol dimethacrylate, 1,6-hexanediol diacrylate, polyethylene glycol dimethacrylate, diallyl phthalate, butadiene, and isoprene. Examples include compounds having two or more bonds.

  The weight average molecular weight (Mw) of the polymer resin constituting the resin particles is usually 15,000 to 500,000, preferably 20,000 to 200,000, more preferably 25,000 to 150,000. The softening point is usually 90 to 140 ° C, preferably 100 to 130 ° C, more preferably 110 to 120 ° C.

  In the present invention, the resin particles may have any structure, for example, may have a single structure obtained by polymerization in one stage, or may be polymerized in multiple stages to form a multilayer resin. It may have a composite structure. In the present invention, the resin particles preferably have a three-layer structure in which an intermediate layer and an outer layer are sequentially laminated in the central portion from the viewpoint of the stability of production and the range of molecular weight design of the resulting toner. When the resin particles have a multilayered composite structure, the amino group-containing monomer content and the weight average molecular weight of the entire particles may be within the above ranges.

  When the resin particles have a composite structure, the amino group-containing monomer may be contained in any layer as long as the amine value of the toner is within the above range, but from the viewpoint of not significantly reducing the chargeability of the toner. It is preferable that it is not contained in the outermost layer which forms.

  In particular, when the resin particles have a three-layer structure in which an intermediate layer and an outer layer are sequentially laminated at the center, the amino group-containing monomer is contained as a constituent monomer at least in the resin as the intermediate layer from the viewpoint of further improving the low-temperature fixability. More preferably, it is contained in the resin as the intermediate layer and the resin as the central portion. When the amino group-containing monomer is contained in the intermediate layer and the central part, the content ratio of the amino group-containing monomer in the intermediate layer is more than the content ratio of the amino group-containing monomer in the central part from the viewpoint of further improving the low-temperature fixability. Larger is preferred. The content ratio of the amino group-containing monomer in the intermediate layer is the weight ratio of the amino group-containing monomer to the total constituent monomers of the resin constituting the intermediate layer, and is usually 0.1 to 15% by weight, preferably 0.3 to 8%. % By weight, in particular 0.5-4% by weight. The content ratio of the amino group-containing monomer in the center is the weight ratio of the amino group-containing monomer to the total constituent monomers of the resin constituting the center, and is usually 0.1 to 10% by weight, preferably 0.1 to 5%. % By weight, in particular 0.1 to 3.5% by weight.

  Regardless of the structure of the resin particles, the resin particles usually contain the acid monomer as a constituent monomer from the viewpoint of easy formation of the resin particles. The content of the acid monomer is not particularly limited as long as the acid value of the toner is within the above range, and is usually 0.1 to 20% by weight, particularly 0.1 to 10% by weight, based on all the constituent monomers.

  In particular, when the resin particles have a three-layer structure, the acid monomer is preferably contained in any layer from the viewpoint of easy formation of the resin particles. At this time, the content of the acid monomer may be such that the total content of the acid monomer with respect to all the constituent monomers of the resin particles is within the above range.

From the viewpoint of cohesiveness between the resin particles and the colorant particles, particularly carbon black, it is preferable that the resin as the outer layer contains an acid monomer as a constituent monomer. The content of the acid monomer in the outer layer is 0.1 to 10% by weight, particularly 0.1 to 10% by weight with respect to all the constituent monomers of the resin constituting the outer layer from the viewpoint of the aggregation property, moisture absorption resistance and charging stability of the toner. 5% by weight is preferred When the acid monomer is contained in the intermediate layer, the content of the acid monomer is usually from the viewpoint of the above-mentioned cohesiveness, moisture absorption resistance and charge stability of the toner. 0.1 to 20% by weight, particularly 0.1 to 10% by weight, based on the constituent monomers.
When an acid monomer is contained in the central part, the content of the acid monomer is usually based on the total constituent monomers of the resin constituting the central part from the viewpoint of the above-mentioned cohesiveness, moisture absorption resistance and charging stability of the toner. 0.1 to 20% by weight, in particular 0.1 to 10% by weight.

When the resin particles have a three-layer structure, the weight average molecular weight of each layer is not particularly limited as long as the weight average molecular weight of the entire resin particles is within the above range, but usually has the following weight average molecular weight.
Weight average molecular weight in the center; 160,000-500,000;
Weight average molecular weight of the intermediate layer; 20,001-159,999;
Weight average molecular weight of outer layer: 15,000-20,000.

  The resin particles can be produced by a wet method such as a so-called emulsion polymerization method or suspension polymerization method, preferably by an emulsion polymerization method. In detail, when employing the emulsion polymerization method, a polymerization composition containing a predetermined monomer is sequentially added and dispersed in an aqueous medium containing a polymerization initiator, and the polymerization proceeds by heating. A plurality of monomers may be added separately, or a plurality of monomers may be mixed and added in advance. The monomer may be added as it is, or may be added as an emulsion prepared by mixing with water or a surfactant in advance. The polymerization temperature and the polymerization time can be appropriately set within the range where the polymerization reaction occurs. The particle diameter of the resin particles is preferably in the range of 50 to 500 nm in terms of weight average particle diameter.

  When obtaining multilayered composite resin particles as resin particles, it is preferable to employ a multistage polymerization method such as an emulsion polymerization method. That is, when producing composite resin particles, resin particles (center part) are formed according to a conventional method such as emulsion polymerization, and a polymerization composition containing a predetermined monomer is added to the dispersion of the resin particles. In addition, it is preferable to employ a method of forming a multilayer (compositing) by performing polymerization. In the case of forming a multilayer structure of three or more layers, the above addition-polymerization is repeated, and an aqueous medium may be added if necessary. In particular, when the composite resin particles have a three-layer structure, from the viewpoint of improving the chargeability by preventing the separation of the wax, the wax may be contained in the intermediate layer by dissolving or dispersing the wax in the polymerization composition for the intermediate layer. Is preferred.

  In addition to the above-described monomers, the polymerization composition usually contains a known chain transfer agent as necessary for adjusting the molecular weight of the polymer. Specific examples of chain transfer agents include n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, 2-mercaptoethanol, diisopropylxanthogen, carbon tetrachloride, trichlorobromomethane, octanethiol, stearylthiol and n- Examples include octyl 3-mercaptopropionate, α-methylstyrene dimer, ethylene glycol bis (3-mercaptopropionate), and the like. The chain transfer agent may be used alone or in combination of two or more.

  The polymerization initiator used in the emulsion polymerization method is not particularly limited as long as it has water solubility. For example, persulfates such as potassium persulfate, sodium persulfate, ammonium persulfate, and acidic sulfite containing these persulfates as one component. Redox initiators combined with reducing agents such as sodium, water-soluble polymerization initiators such as hydrogen peroxide, 4,4′-azobiscyanovaleric acid, t-butyl hydroperoxide, cumene hydroperoxide, and these water-soluble polymerizations A redox initiator system, a benzoyl peroxide, 2,2′-azobis-isobutyronitrile, etc. used in combination with a reducing agent such as a ferrous salt as a one-component initiator. These polymerization initiators may be added to the polymerization system before, simultaneously with the addition of the monomer, or after the addition, and these addition methods may be combined as necessary.

The aqueous medium usually contains a surfactant. As the surfactant, at least one selected from a cationic surfactant, an anionic surfactant, and a nonionic surfactant is used. Two or more of these surfactants may be used in combination. Among these, it is particularly preferable to mainly use an anionic surfactant.
Specific examples of the cationic surfactant include dodecyl ammonium chloride, dodecyl ammonium bromide, dodecyl trimethyl ammonium bromide, dodecyl pyridinium chloride, dodecyl pyridinium bromide, hexadecyl trimethyl ammonium bromide and the like.
Specific examples of anionic surfactants include sulfonate (sodium dodecylbenzenesulfonate, sodium arylalkylpolyethersulfonate), sulfate ester salt (sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, etc.) ), Fatty acid salts (sodium oleate, sodium laurate, sodium caprate, sodium caprylate, sodium caproate, potassium stearate, calcium oleate, etc.) can be exemplified as suitable ones. it can. Also, polyethylene oxide, polypropylene oxide, combination of polypropylene oxide and polyethylene oxide, ester of polyethylene glycol and higher fatty acid, alkylphenol polyethylene oxide, ester of higher fatty acid and polyethylene glycol, ester of higher fatty acid and propylenoxide, sorbitan ester Nonionic surfactants such as can also be used.
These surfactants are used as an emulsifier at the time of emulsion polymerization, but may be used for other steps or purposes.

  As the wax, various known ones can be exemplified. Specific examples of such waxes include olefinic waxes such as low molecular weight polyethylene, low molecular weight polypropylene, copolymerized polyethylene, grafted polyethylene, and grafted polypropylene, long chains such as behenyl behenate, montanate, and stearyl stearate. Higher grades such as ester waxes having aliphatic groups, plant waxes such as hydrogenated castor oil and carnauba wax, ketones having long chain alkyl groups such as distearyl ketone, silicone waxes having alkyl groups and phenyl groups, and stearic acid Fatty acids, higher fatty acid amides such as oleic acid amide, stearic acid amide, long chain fatty acid alcohols, long chain fatty acid polyhydric alcohols such as pentaerythritol, and their partial esters, paraffinic wax, Fischer-Tropschwak Like it is exemplified.

Suitable waxes constituting the toner of the present invention include those composed of a crystalline ester compound (hereinafter referred to as “specific ester compound”) represented by the following general formula (1).
Formula ^{(1): R 1 - (} OCO-R 2) n
(In the formula, R ¹ and R ² each independently represents an optionally substituted hydrocarbon group having 1 to 40 carbon atoms, and n is an integer of 1 to 4).

In General formula (1) which shows a specific ester compound, R < ¹ > and R < ² > show the hydrocarbon group which may have a substituent, respectively. The hydrocarbon group R ¹ has 1 to 40 carbon atoms, preferably 1 to 20 carbon atoms, more preferably 2 to 5 carbon atoms. The hydrocarbon group R ² has 1 to 40 carbon atoms, preferably 16 to 30 carbon atoms, more preferably 18 to 26 carbon atoms. In the general formula (1), n is an integer of 1 to 4, preferably 2 to 4, more preferably 3 to 4, and particularly preferably 4. The specific ester compound can be suitably synthesized by a dehydration condensation reaction between an alcohol and a carboxylic acid.

  Specific examples of the specific ester compound include compounds represented by the following formulas (1w) to (22w).

  Among these waxes, a wax having a melting point of 100 ° C. or lower is more preferable for improving the low-temperature fixability, and a more preferable wax has a melting point in the range of 50 to 100 ° C., particularly preferably 55 to 90 ° C. It is a range. When the melting point exceeds 100 ° C., the effect of reducing the fixing temperature is poor.

  The toner particles constituting the toner of the present invention are obtained by aggregating / fusing at least resin particles and colorant particles in an aqueous medium by salting out. As the resin particles, amino group-containing monomer-free resin particles may be used together with the resin particles containing an amino group-containing monomer as a constituent monomer. The amino group-containing monomer-free resin particles are the same as the resin particles containing an amino group-containing monomer except that the amino group-containing monomer is not contained as a constituent monomer. When using amino group-containing monomer-free resin particles, if the amount of amino group-containing monomer with respect to all monomers constituting all resin particles used is within the above range, the obtained toner has a predetermined amine value. Good. In addition to the resin particles and the colorant particles, toner constituent materials such as wax particles and charge control agent particles may be added to the aqueous medium, and may be aggregated / fused together with the resin particles and the colorant particles.

  Salting-out is described in detail, for example, in the literature and books on colloids, published by Polymer Publications, by Soichi Muroi, "Chemistry of Polymer Latex", Chapter 6 and later, and compresses the electric double layer of dispersed particles in a solvent. And a means for aggregating the particles. In the present invention, a flocculant is usually used to cause salting out.

  As the aggregating agent, the polarity of the polar functional group of the resin particles, a surfactant having a polarity opposite to that of the surfactant used in the dispersion such as the resin particle dispersion or the colorant particles aggregated together with the resin particles, divalent The above inorganic metal salts can be suitably used. In general, the higher the valence, the greater the cohesive force. Therefore, the coagulant is selected in consideration of the aggregation speed of the resin particles and the stability of the production process. Specific examples of the flocculant include, for example, metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, aluminum sulfate, and polyaluminum chloride, polyaluminum hydroxide, calcium polysulfide, etc. And inorganic metal salt polymers.

  In adding the flocculant, it is generally preferable to keep the temperature of the dispersion system at 40 ° C. or lower from the viewpoint of suppressing rapid aggregation in the system. When the flocculant is added under conditions where the temperature exceeds 40 ° C., rapid aggregation occurs, which may make it difficult to control the particle size, and the bulk density of the obtained particles may be problematic. Further, usually, the particles are heated to cause the aggregation and fusion of the particles to proceed simultaneously to produce fused particles (toner particles). Stirring may be carried out in a reaction tank having a conventional well-known stirrer such as a paddle blade, squid blade, three retreat blades, max blend blade, double helical, etc., or a homogenizer, homomixer, Henschel mixer or the like is used. You can also. The number of rotations of stirring is preferably set so that the system is in a turbulent state.

  The particle size growth by aggregation (salting out reaction) can be controlled relatively easily by adjusting the pH and temperature of the dispersion. Although the pH value varies depending on the zeta potential and isoelectric point of the reaction system, the type / amount of the coagulant used, the type / amount of the surfactant, and the target toner particle size, it cannot be uniquely defined. For example, when an aluminum-based flocculant is used, the pH at which the salting-out effect is effectively expressed is 2 to 6, and in the case of a magnesium-based flocculant, the pH is 7 to 12.

  Similarly to pH, the reaction temperature cannot be uniquely defined, but it is preferable that the reaction temperature is in the range of 40 to 95 ° C. so that the particle size growth can be controlled. A temperature higher than this range is not preferable because the shape tends to be almost spherical due to the simultaneous progress of aggregation and fusion and lacks shape controllability. The reaction is maintained at a predetermined temperature for at least 10 minutes or more, and more preferably for 20 minutes or more to obtain toner particles having a desired particle diameter. If the reaction temperature is lower than the Tg of the resin, the particles only aggregate and the fusion does not proceed. If the reaction temperature is higher than the Tg, the aggregation and fusion of the particles proceed simultaneously. If the fusion does not proceed, the fusion can be performed by raising the temperature after aggregation.

In the aggregation / fusion process, the temperature may be increased at a constant rate up to a predetermined temperature, or may be increased in stages. You may adjust suitably the rotation speed of the stirring blade of a system.
The particle agglomeration speed and particle size control are performed by operating the reaction temperature and the number of revolutions of stirring while monitoring the agglomeration state of the particles in the system with a microscope or particle size measuring instrument until the desired particle size is reached. . When the desired particle size is reached, an operation for reducing the cohesive force is performed in order to stop the growth of the particle size of the system or slow down the growth rate.

  As a means for reducing the cohesive force of the system, a means for increasing the stability of particles or a means for reducing the aggregating action of the aggregating agent can be used. For example, as a means to increase the stability of the particles, the pH of the system is adjusted to the stable side (for example, from the neutral to the alkaline side when agglomerating under acidic conditions, and from the neutral to the acidic side when aggregated under alkaline conditions. Or a method such as adding the above-mentioned surfactant is used. In addition, as a means for reducing the aggregating action of the aggregating agent, metal cations having different valences can be added, and the aggregating force can be remarkably reduced by an antagonistic action. It is possible to increase the temperature after reducing the cohesive force to promote fusion or control the shape to the spherical side.

  Examples of the colorant that is aggregated / fused together with the resin particles include various inorganic pigments, organic pigments, and dyes. A conventionally well-known thing can be used as an inorganic pigment. Any pigment can be used, but suitable inorganic pigments are exemplified below. Examples of the black pigment include carbon black such as furnace black, channel black, acetylene black, thermal black, and lamp black, and magnetic powder such as magnetite and ferrite. These inorganic pigments can be used alone or in combination as required.

A conventionally well-known thing can be used as an organic pigment. Although any pigment can be used, specific organic pigments are exemplified below.
As pigments for magenta or red, CI pigment red 2, CI pigment red 3, CI pigment red 5, CI pigment red 6, CI pigment red 7, CI pigment red 15, CI pigment red 16, CI pigment red 48: 1 CI Pigment Red 53: 1, CI Pigment Red 57: 1, CI Pigment Red 81: 3, CI Pigment Red 122, CI Pigment Red 123, CI Pigment Red 139, CI Pigment Red 144, CI Pigment Red 149, CI Pigment Red 166, CI Pigment Red 177, CI Pigment Red 178, CI Pigment Red 184, CI Pigment Red 185, CI Pigment Red 222, CI Pigment Red 238, and the like.

CI pigment orange 31, CI pigment orange 43, CI pigment yellow 12, CI pigment yellow 13, CI pigment yellow 14, CI pigment yellow 15, CI pigment yellow 17, CI pigment yellow 74, CI pigment orange 31, CI pigment orange 43, CI pigment yellow 12, CI pigment yellow 13, CI pigment yellow 13 And CI Pigment Yellow 93, CI Pigment Yellow 94, CI Pigment Yellow 97, CI Pigment Yellow 138, CI Pigment Yellow 180, and the like.
Examples of the pigment for green or cyan include CI pigment blue 15, CI pigment blue 15: 2, CI pigment blue 15: 3, CI pigment blue 16, CI pigment blue 60, CI pigment green 7, and the like.

CI Solvent Red 1, 49, 52, 58, 63, 111, 122, CI Solvent Yellow 19, 44, 77, 79, 81, 82, 93, etc. 98, 103, 104, 112, 162, CI Solvent Blue 25, 36, 60, 70, 93, 95, and the like, and mixtures thereof can also be used.
These organic pigments and dyes can be used alone or in combination as desired.

  These colorants are preferably used in the form of a dispersion dispersed in water in the presence of the surfactant. The colorant dispersion preferably has a dispersed particle diameter of 1 μm or less, more preferably in the range of 100 to 500 nm.

  It is preferable that an aminosilane coupling agent is added to the colorant dispersion from the viewpoint of moisture absorption resistance and productivity (aggregation between resin particles and colorant particles) of the toner. That is, by adding the aminosilane coupling agent, the stability of the colorant particles and the resin particles in the dispersion is improved, so that the productivity of the toner is improved. Furthermore, since the amount of the acid monomer in the outermost layer of the resin particles can be effectively reduced, the moisture absorption resistance of the toner is improved. Even if an aminosilane coupling agent is added, most of the aminosilane coupling agent is adsorbed on the colorant particles, and the amount of aminosilane coupling agent having an amine value that tends to be positively charged is reduced on the toner surface. It does not hinder the chargeability of the toner, particularly the negative chargeability of the negatively chargeable toner.

  Examples of the aminosilane coupling agent include γ-aminopropyltriethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, and γ- (2-aminoethyl) -γ-aminopropylmethyldimethoxysilane. , Γ-anilinopropyltrimethoxysilane and the like. The amount of the aminosilane coupling agent to be used is not particularly limited, but 0.1 to 20% by weight, particularly 0.1 to 10% by weight with respect to the colorant is appropriate.

  When using wax as particles and agglomerating / fusion with resin particles, it is desirable to use a wax in the form of a dispersion dispersed in water in the presence of the surfactant. At this time, the wax dispersion preferably has a dispersed particle size of 1 μm or less, and more preferably in the range of 100 to 500 nm.

  As the charge control agent, any known one can be used alone or in combination. Taking into account the compatibility with color toners (the charge control agent itself is colorless or light and does not impair the color tone of the toner), quaternary ammonium salt compounds are positively charged, and salicylic acid or alkylsalicylic acid chromium is negatively charged. Metal salts with zinc, aluminum and the like, metal complexes, metal salts of benzylic acid, metal complexes, amide compounds, phenol compounds, naphthol compounds, phenol amide compounds and the like are preferable. These charge control agents can be used as dispersions using the above-mentioned surfactants and the like.

  The toner particles obtained as described above have a volume average particle diameter of 3 to 10 μm, particularly 4 to 7 μm, and are useful as next-generation high-resolution toner particles.

The obtained toner particles are usually subjected to washing treatment, drying treatment and external addition treatment.
In the cleaning process, the toner particles are filtered from the obtained dispersion of toner particles, and deposits such as surfactants and flocculants are removed from the filtered toner particles (cake-like aggregates). Cleaning treatment is performed. As a means for washing the filtered toner particles, a conventionally known washing method is used, for example, a method of reslurrying and stirring the filtered toner particles with pure water in a container equipped with a stirring device, A method such as applying pure water during vacuum filtration or centrifugal filtration is used. Further, at this time, in order to elute / remove the surfactant and metal salts remaining in the toner particles, an acidic or alkaline treatment may be performed in advance before washing with pure water.

  In the drying process, the toner particles are usually dried until the water content of the toner particles is 1% by weight or less, preferably 0.6% by weight or less.

  In the external addition treatment step, a single or plural kinds of external additives are added to and mixed with the dried toner particles to obtain a toner. External additives include various inorganic oxide fine particles such as silica, alumina, titania, strontium titanate and cerium oxide, hydrophobized fine particles as required, vinyl polymers, metal soaps such as zinc stearate and calcium stearate Etc. can be used. Particularly in the case of full-color toner, since the process becomes complicated, it is desirable to add functional particles that can further improve fluidity, chargeability, transferability, and cleaning properties. The addition amount of the external additive is preferably in the range of 0.05 to 5 parts by weight with respect to the toner particles.

  Since the toner of the present invention has an amine value within the above range, the charge that can be held is not particularly limited. For example, the toner of the present invention may be used as a negatively chargeable toner having a negative charge, or a positive charge having a positive charge. It may be used as a functional toner. Therefore, the toner of the present invention is useful without being limited in use. When the toner of the present invention is used as a positively chargeable toner, it is preferable to use the positive charge control agent as an essential component. From the viewpoint of manufacturing cost, it is preferable to use the toner as a negatively chargeable toner. .

  The toner of the present invention is used as a magnetic or non-magnetic one-component developer or two-component developer. When the toner of the present invention is mixed with a carrier to be used as a two-component developer, the carrier may be a conventional metal such as iron, ferrite, magnetite, or an alloy of such a metal with a metal such as aluminum or lead. From known materials can be used.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, the aspect of this invention is not limited to this. “Parts” in the text means “parts by weight”.

<Colorant dispersion>
(Colorant dispersion K1)
25 kg of surfactant (E27C; manufactured by Kao Corporation) and 25 g of aminosilane coupling agent (N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane) were added to 1 kg of Mogal L (CABOT), and Ultra Turrax Was premixed for 1 hour to obtain a colorant dispersion K1 (solid content concentration 13.5%).

(Colorant dispersion K2)
Add 50g of surfactant (SDS; manufactured by Mitsubishi Gas Chemical Company) to 1kg of Mogul L (Cabot), pre-mix for 1 hour with Ultra Turrax, and colorant dispersion K2 (solid content concentration 13.5%) It was.

<Toner particles>
Example 1
(1) Formation of core particles (center part) (first stage polymerization)
(Dispersion medium 1)
4.05 g sodium dodecyl sulfate
Ion exchange water 2500.00g
The dispersion medium 1 was charged into a 5000 ml separable flask equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introducing device, and the temperature in the flask was raised to 80 ° C. while stirring at a stirring speed of 230 rpm under a nitrogen stream. Allowed to warm.
(Monomer solution 1)
Styrene 569.00g
n-Butyl acrylate 165.00g
Methacrylic acid 56.00 g
Dimethylaminoethyl methacrylate 10.00g
n-octyl mercaptan 16.51 g
To this activator solution, an initiator solution prepared by dissolving 9.62 g of a polymerization initiator (potassium persulfate) in 200 g of ion-exchanged water was added, and the monomer solution 1 was dropped over 90 minutes. Was polymerized by heating and stirring at 80 ° C. for 2 hours to prepare a latex. This is referred to as “latex (1H)”. The weight average particle diameter of the latex (1H) was 70 nm.

(2) Formation of intermediate layer (second stage polymerization)
(Monomer solution 2)
Styrene 123.80g
n-Butyl acrylate 36.50 g
Methacrylic acid 12.23g
Dimethylaminoethyl methacrylate 3.08g
n-octyl mercaptan 0.72 g
WEP-5 (Nippon Yushi Co., Ltd.) 93.80 g
In a flask equipped with a stirrer, the monomer solution 2 described above was charged and heated to 80 ° C. and dissolved to prepare a monomer solution.

(Dispersion medium 2)
C ₁₀ H ₂₁ (OCH ₂ CH ₂ ) ₂ OSO ₃ Na 0.60 g
Ion exchange water 2700.00g
On the other hand, after the dispersion medium 2 is heated to 98 ° C. and 32 g of the latex (1H), which is a dispersion medium of core particles, is added to the dispersion medium in terms of solid content, a mechanical disperser “CLEA” having a circulation path is added. The monomer solution 2 was mixed and dispersed for 8 hours by “CLEARMIX” (manufactured by M Technique Co., Ltd.) to prepare a dispersion (emulsion) containing emulsified particles (oil droplets).

  Next, an initiator solution prepared by dissolving 6.12 g of a polymerization initiator (potassium persulfate) in 250 ml of ion-exchanged water is added to this dispersion (emulsion), and this system is heated and stirred at 82 ° C. for 12 hours. Thus, polymerization (second stage polymerization) was performed to obtain latex (a dispersion of composite resin particles having a structure in which the surface of latex (1H) particles was coated). This is referred to as “latex (1HM)”. The latex had a weight average particle diameter of 120 nm.

(3) Formation of outer layer (third stage polymerization)
An initiator solution obtained by dissolving 8.8 g of a polymerization initiator (KPS) in 350 ml of ion-exchanged water is added to the latex (1HM) obtained as described above, and 350 g of styrene under a temperature condition of 82 ° C. 95 g of n-butyl acrylate, 5 g of methacrylic acid, and 1.0 mol% of n-octyl mercaptan with respect to the above monomer and uniformly stirred were added dropwise to this activator solution over 1 hour. After completion of the dropping, polymerization (third stage polymerization) was performed by heating and stirring for 2 hours, followed by cooling to 28 ° C. and an intermediate layer made of latex (latex (1H) and a second stage polymerization resin). And an outer layer made of a third-stage polymerization resin, and a dispersion of composite resin particles) containing WEP-5 in the second-stage polymerization resin layer. This latex is referred to as “latex (1HML)”. The latex had a weight average particle diameter of 150 nm.

(4) Formation of toner particles 250.0 g of latex (1HML) (in terms of solid content), 900 g of ion-exchanged water, and 150 g of colorant dispersion K1 were mixed with a temperature sensor, a cooling tube, a nitrogen introducing device, and a stirring device. It stirred in the attached reaction container (four necked flask). After adjusting the temperature in the container to 30 ° C., 5N aqueous sodium hydroxide solution was added to this solution to adjust the pH to 10.0.
Next, an aqueous solution in which 65.0 g of magnesium chloride hydrate was dissolved in 1000 ml of ion-exchanged water was added over 10 minutes at 30 ° C. with stirring. After standing for 3 minutes, the temperature was raised to 92 ° C. to produce fused particles. In this state, the particle size of the fused particles was measured with “Coulter Counter TA-II”. When the number average particle size reached 6.1 μm, 80.4 g of sodium chloride was dissolved in 1000 ml of ion-exchanged water. The aqueous solution was added to stop the particle growth, and the mixture was further heated and stirred at a liquid temperature of 94 ° C. as an aging treatment, thereby continuing particle fusion and phase separation of the crystalline substance (aging step). In this state, the shape of the fused particles was measured with “FPIA-2000”, and when the shape factor reached 0.960, the mixture was cooled to 30 ° C. and stirring was stopped. The produced fused particles were filtered, repeatedly washed with ion exchange water at 45 ° C., and then dried with hot air at 40 ° C. to obtain toner particles.

(Examples 2-7 and Comparative Examples 1-2)
In the center forming step, the intermediate layer forming step, and the outer layer forming step, the amino group-containing monomer and the acid monomer were used so that the usage ratio relative to the total amount of monomers in each step was the amount shown in Table 1, and coloring Toner particles were obtained in the same manner as in Example 1 except that the agent dispersion liquid listed in Table 1 was used. In Comparative Example 1, the particle size distribution reached a double peak at the initial stage of the temperature rise for the generation of fused particles. Formed.

<Example of toner production>
Hydrophobic silica (number average primary particle size = 12 nm, degree of hydrophobicity = 68) is added to the toner particles at a ratio of 1% by weight, and hydrophobic titanium oxide (number average primary particle size = 20 nm, hydrophobic). Degree = 63) was added at a ratio of 1.2% by weight and mixed with a Henschel mixer to produce a toner. The toner particles did not change in shape and particle size depending on the addition of hydrophobic silica and hydrophobic titanium oxide.

<Toner evaluation>
(Cohesiveness)
After the addition of the flocculant, the stability of the agglomerated particles was evaluated by the waveform of the particle size distribution at 60 ° C., 70 ° C., 80 ° C., and 90 ° C. during the heating to 92 ° C.
○: A single sharp distribution was maintained even when the temperature rose;
Δ: Even if the temperature rose, the distribution was slightly broad but maintained a single distribution;
X: Latex particles and colorant particles were completely separated at the initial stage of temperature rise, resulting in a double peak.

(Heat resistant storage)
20 g of toner was put in a glass bottle and allowed to stand at a high temperature of 50 ° C. for 24 hours, and then the toner was visually confirmed.
○: No aggregation toner, no problem at all;
△: Light soft agglomeration exists, but can be solved easily with a light force and has no practical problem;
X: Strong agglomerates exist, which cannot be easily solved, and have practical problems.

(Fixability)
Evaluation was performed using a color laser printer (magicolor 2300DL; manufactured by Minolta EMS Co., Ltd.) modified so that the temperature of the fixing device can be arbitrarily controlled. The four developers were filled with the same toner. The fuser employs an oilless fixing mechanism.
· The temperature of the offset fixing roller is changed, the low temperature side is's a picture of the solid image obtained by superimposing three layers of the total coating weight 15 g / m ^2, the high-temperature side of the deposition amount 0~5.0g / m ² monochrome A gradation image was drawn, and the image on the paper after passing through the fixing roller was observed. In any image, evaluation was performed based on a fixing temperature width (non-offset temperature width) in which a low temperature offset and a high temperature offset do not occur. As the paper, CF paper (basis weight 80 g / m ² ) as standard paper for CF900 was used. Those that could be confirmed even with a slight offset were considered defective.
○: The non-offset temperature range is wider than 40 ° C;
Δ: The non-offset temperature range is 30 ° C. or higher and 40 ° C. or lower;
X: The said non-offset temperature range is less than 30 degreeC.

And fixing separation property at the offset evaluation, by setting the roller temperature to the temperature lower limit value + 15 ° C. of causing no offset, using the MT paper (basis weight 64g / ^{m 2),} 3 of total coating weight 15 g / ^{m 2} Layered solid images were drawn. On the paper, the image is missing 5 mm at the upper and lower ends and the left and right ends. No toner wrapping around the fixing roller, “○” indicates that the toner has passed through, and “△” indicates toner that has passed through the paper but has some density unevenness in the image. The toner that could not be passed through was marked “x”.

-Low-temperature fixability The copy image fixed on copy paper at 130 ° C in the above evaluation method for separation was folded in half from the middle, and the peelability was judged visually.
○: No peeling occurred and no problem in practical use;
Δ: Some peeling occurs but there is no practical problem;
X: There is a problem in practical use.

(Chargeability)
Color laser printer (magicolor 2300DL; manufactured by Minolta EMS Co., Ltd.) L / L environment (low temperature and low humidity environment: 10 ° C, 15%) and N / N (20 ° C, 50%) initial and 2000 continuous copies Later (after durability), the intermediate transfer member was visually evaluated. Note that continuous copying was performed under the condition of a predetermined print pattern and a B / W ratio of 6%.
○: No fogging and no problem in any environment and printing durability;
Δ: Slight fogging is observed in any environment and printing durability, but it is not visible on the image;
X: Fog is clearly generated in any environment and printing durability, and can be confirmed on an image.

(Hygroscopic resistance)
The toner was dried in advance in a vacuum dryer for 24 hours and then conditioned in a high-temperature and high-humidity environment (30 ° C./80%) for 24 hours, and the water content W was measured with a Karl Fischer moisture meter. W is the amount of water (kg) per kg of toner at the time of drying.
○: W ≦ 0.5
Δ: 0.5 <W ≦ 1.0
×: 1.0 <W

(Image density)
A solid image was drawn and the entire density unevenness was observed.
○: A solid image with a constant image density was obtained;
Δ: The image density is uneven at the leading edge and the trailing edge of the solid image, but it was within an acceptable range level;
X: There was a large difference in image density between the leading edge and the trailing edge of the solid image.

<Measurement method>
(Acid value)
Dissolve 10 mg of sample in 50 ml of toluene and remove the colorant with a 0.1 μm membrane filter. Using a mixed indicator of 0.1% bromothymol blue and phenol red, titrated with a standardized N / 10 potassium hydroxide / alcohol solution, and calculated from the consumption of N / 10 potassium hydroxide / alcohol solution. is there.

(Molecular weight of resin)
The molecular weight of the resin is obtained as a weight molecular weight distribution by a gel permeation chromatography method (GPC method), and is a converted molecular weight obtained by creating a calibration curve with monodisperse standard polystyrene. The measurement conditions were as follows: JASCO TWINCLE HPLC as the GPC apparatus, SHODEX RI SE-31 as the detection apparatus, SHODEX GPCA-80M × 2 and KF-802 as the column, tetrahydrofuran as the solvent, and a flow rate of 1.2 ml / min. The value in the condition is shown.

(Softening point (Tm))
Using a flow tester (CFT-500: manufactured by Shimadzu Corporation), 1.0 g of a sample to be measured is weighed, a die of h1.0 mm × φ1.0 mm is used, a heating rate is 3.0 ° C./min, and a preheating time is used. Measurement was performed under the conditions of 180 seconds, a load of 30 kg, and a measurement temperature range of 60 to 150 ° C., and the temperature at which the above sample flowed out 1/2 was defined as a resin softening point (Tm).

(Particle size of resin particles and latex)
Measured with a Microtrac UPA150 (manufactured by Nikkiso Co., Ltd.).
(Particle size of toner particles)
Measured with Multisizer II (Beckman Coulter, Inc.).

Claims (4)

An electrostatic charge image developing toner comprising toner particles obtained by agglomerating / fusing resin particles obtained by polymerizing a polymerizable monomer containing at least an amino group-containing monomer and colorant particles in an aqueous medium,
Amine value of the toner is Ri 0.05~5KOHmg / g Der,
An electrostatic charge image developing characterized in that the resin particles have a three-layer structure in which an intermediate layer and an outer layer are sequentially laminated in the center, and the resin as the outer layer contains an acid monomer as a constituent monomer toner.   The resin particle has a three-layer structure in which an intermediate layer and an outer layer are sequentially laminated in the center, and at least the resin as the intermediate layer contains an amino group-containing monomer as a constituent monomer. Toner for developing electrostatic images.   The resin particle has a three-layer structure in which an intermediate layer and an outer layer are sequentially laminated in the center, and the resin as the intermediate layer and the resin as the center include an amino group-containing monomer as a constituent monomer The toner for developing an electrostatic image according to claim 1. 4. The toner for developing an electrostatic charge image according to claim 1, wherein the colorant particles are used by being dispersed by an amino silane coupling agent.