JP2009265644A - Electrostatic charge image developing toner and method for manufacturing thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic charge image developing toner can low temperature fixation, have a wide width of fixing temperature. <P>SOLUTION: The electrostatic charge image developing toner includes a binder resin and a colorant, wherein the binder resin is a vinyl type crystalline resin, and the ratio (Dv/Dn) of volume-average particle size Dv of the toner to number-average particle size Dn is 1.2 or less. Further, the electrostatic charge image developing toner comprising the binder resin and colorant, when a storage modulus at melting point (Tm)+30°C is expressed by G'(Tm+30) and a storage modulus at melting point (Tm)+60°C is expressed by G'(Tm+60), satisfies the relations (1), (2): 10 Pa≤G'(Tm+30)≤10.000 Pa (1) and 1 Pa≤G'(Tm+60)≤5.000 Pa (2), and has the ratio (Dv/Dn) of volume-average particle size Dv of the toner to number-average particle size Dn of 1.2 or less. The electrostatic charge image developing toner has a narrow particle size distribution, is suitable for high-resolution molding property and can provide a high quality image with low energy. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electrostatic charge image developing toner used in electrophotography, electrostatic photography and the like.

In recent years, in order to achieve miniaturization, high speed, and energy saving of an image forming apparatus using an electrophotographic method, toner for developing electrostatic images used in the apparatus is required to have low temperature fixability. In order to improve the low-temperature fixability of the toner, it is important not only to lower the lower limit of the fixable temperature but also to increase the toner fixing temperature range.
Conventionally, in order to achieve this, a relatively low molecular weight component and a relatively high molecular weight component have been used in combination as a binder resin component contained in the toner. However, in this method, the low molecular weight component may cause the chargeability of the toner to deteriorate. Further, when the toner is used for a long period of time, there is a problem that a low molecular weight component contaminates the carrier, the photoconductor, the developing blade and the like and a clear image cannot be obtained.

  For example, it has been shown that two types of polyester resins are used as binder resins in order to obtain contradictory properties such as low-temperature fixability, releasability, and blocking resistance (see Patent Document 1). Although it is described that the toner starts to soften at around 80 ° C. and reaches a fixable level and does not flow at 180 ° C. and can maintain the elasticity, the offset property is achieved, but an amorphous resin is used. Therefore, the problem of low-temperature fixing has not been sufficiently addressed.

  In addition, an electrophotographic toner in which the viscoelasticity of a binder resin is specified has been proposed with the object of achieving both low-temperature fixability and offset resistance (see Patent Document 2). A toner containing a binder resin composed of a crystalline polystearyl acrylate copolymer having a cross-linked structure has been proposed. However, a uniform chargeability cannot be obtained due to a wide particle size distribution. ”Occurs, it is difficult to obtain good image quality.

  It has been shown that a toner containing, as a main component, a crystalline polyester containing a sulfonic acid group-containing divalent or higher carboxylic acid as a copolymer component has excellent blocking properties and image storage stability and can achieve low-temperature fixing. (See Patent Document 3). However, since an organic solvent is not used for dissolving the resin in order to increase the yield, it is limited to a crystalline polyester composed of a specific raw material monomer.

  When such a crystalline polyester is used, the polymerization of the polyester is generally performed by bulk polymerization. Therefore, when the toner is produced in the aqueous system, a complicated process for emulsifying the toner once taken out from the polymerization apparatus into the aqueous system is required, which is expensive. Moreover, since heavy metals are used for the polymerization catalyst used for bulk polymerization, there has been a problem pointed out about its toxicity. Furthermore, polyester is produced by condensation polymerization, but it is difficult to increase the degree of polymerization in condensation polymerization, and its molecular weight is at most tens of thousands in terms of weight average molecular weight. Therefore, when cross-linking is performed to control viscoelasticity, viscosity and elasticity are not improved with a small amount of cross-linking, and compatibility is lost when the cross-linking is excessive. Therefore, designing the viscoelasticity of a toner containing such a polyester within an appropriate range is accompanied by great difficulty.

On the other hand, in order to provide high image printing, the particle size distribution of the toner needs to be sharp. This is because when the coarse particles are contained, the toner charge amount distribution becomes broad and a phenomenon called “selective development” occurs. “Selective development” is a phenomenon in which, when the toner charge amount distribution is broad, only the toner having the charge amount necessary for development at the time of copying is developed and consumed. Therefore, a good image can be obtained at the initial stage of copying, but the density gradually decreases as the copying continues, and the toner particle size increases, resulting in a rough image. Such a phenomenon is said to be inferior in selective developability. Further, the coarse powder having a low charge amount tends to significantly reduce the guaranteed life number.

JP 2004-184551 A JP 2000-352839 A JP 2001-305996 A

  The present invention has been made in view of the above-described prior art, and has an excellent electrostatic charge image development suitable for the formation of a high-quality image, having good fixability at low temperatures, a wide fixing temperature range, a sharp particle size distribution. An object of the present invention is to provide a toner.

As a result of intensive studies, the present inventor has found that the above problem can be solved when the binder resin constituting the toner for developing an electrostatic charge image is a vinyl-based crystalline resin having a specific particle size distribution. Thus, the present invention has been completed.
That is, the gist of the present invention is as follows.
(1) In an electrostatic charge image developing toner containing a binder resin and a colorant, the binder resin is a vinyl-based crystalline resin and has a volume average particle diameter (Dv) and a number average particle diameter (Dn) of the toner. A toner for developing electrostatic images, wherein the ratio (Dv / Dn) is 1.2 or less.
(2) The electrostatic charge image development according to (1) above, wherein the ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) of the toner is 1.1 or less. Toner.
(3) The toner for developing an electrostatic charge image according to (1) or (2), wherein the melting point (Tm) of the toner is Tm ≦ 100 ° C.
(4) The toner for developing an electrostatic charge image according to the above (1) to (3), wherein the toner has a melting point (Tm) of Tm ≧ 40 ° C.
(5) The toner for developing an electrostatic charge image according to the above (1) to (4), wherein the binder resin has a THF-soluble component having a weight average molecular weight (Mw) of Mw ≧ 10000.
(6) The toner for developing an electrostatic charge image according to (1) to (5), wherein the binder resin has an alkyl group in a side chain of a monomer constituting the binder resin.
(7) The electrostatic image developing toner according to any one of (1) to (6), wherein the colorant is cyan.
(8) In a toner for developing an electrostatic charge image containing a binder resin and a colorant, the storage elastic modulus at the melting point (Tm) + 30 ° C. of the toner is G ′ (Tm + 30), and the storage elastic modulus at the melting point of the toner + 60 ° C. is G ′. When (Tm + 60), the conditions of the following formulas (I) and (II) are satisfied,
10 Pa ≦ G ′ (Tm + 30) ≦ 10000 Pa (I)
1 Pa ≦ G ′ (Tm + 60) ≦ 5000 Pa (II)
A toner for developing electrostatic images, wherein a ratio (Dv / Dn) of a volume average particle diameter (Dv) to a number average particle diameter (Dn) of the toner is 1.2 or less.
(9) The static modulus according to (1) to (8), wherein the storage elastic modulus G ′ (25) at 25 ° C. of the toner is G ′ (25) ≧ 1.0 × 10 ⁷ Pa. Toner for charge image development.
(10) The toner for developing an electrostatic charge image according to (1) to (9), which is produced by an emulsion aggregation method.

According to the present invention, it is possible to provide an electrostatic charge image developing toner that can be fixed at low temperature, has a wide fixing temperature range, and has a sharp particle size distribution. As a result, it is possible to provide a high-quality image with low energy, which cannot be achieved conventionally.

FIG. 4 is a diagram illustrating a state in which the aggregate particle size grows and the toner particle size distribution changes in the manufacturing process of the developing toner 1. FIG. 6 is a diagram illustrating a change in storage elastic modulus with respect to a temperature of developing toner 2.

Hereinafter, the present invention will be described in detail, but the present invention is not limited to the following embodiments, and can be arbitrarily modified without departing from the gist of the present invention.
The toner for developing an electrostatic charge image of the present invention includes at least a binder resin and a colorant as its constituent components, and includes a charge control agent, externally added fine particles, and other additives.

  As the binder resin used in the present invention, a vinyl-based crystalline resin is used.

  The vinyl-based resin is a polymer in which one or two or more types of vinyl monomers are combined with a high degree of polymerization by a reaction such as radical polymerization. The crystalline resin is a resin having a crystal structure in a solid state and has a feature of having a melting point. On the other hand, a non-crystalline resin is a resin that does not crystallize even when the temperature is lowered and solidifies in a completely amorphous state by glass transition. Can be used as a crystalline resin. That is, the crystalline resin of the present invention includes those which show partial crystallinity and show a glass transition phenomenon by lowering the temperature further below the melting point.

The monomer constituting the vinyl crystalline resin may have an alkyl group in the side chain. When it has a side chain, the lower limit of the carbon number of the alkyl group is preferably 18. Further, the upper limit of the carbon number of the alkyl group is preferably 30, and more preferably 26. When the number of carbon atoms is smaller than the lower limit, the melting point becomes room temperature or lower and toner storage stability is deteriorated. If it is larger than the upper limit, it can be fixed only at a high temperature.
A plurality of these monomers may be used or may be copolymerized.
Examples of the monomer constituting the vinyl crystalline resin include long-chain alkyl (meth) acrylates such as stearyl acrylate and behenyl acrylate.

The vinyl crystalline resin may be copolymerized with a monomer having two or more functional groups (polyfunctional monomer). When a crosslinking monomer is used for the vinyl crystalline resin, a polyfunctional monomer having radical polymerizability is used as the crosslinking agent shared with the above-described monomer, such as divinylbenzene, hexanediol diacrylate, nonanediol diacrylate, Examples include ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol acrylate, and diallyl phthalate. A monomer having a reactive group in a pendant group, such as glycidyl methacrylate, methylol acrylamide, or acrolein, can be used.

The proportion of the polyfunctional monomer in the monomer constituting the polymer primary particles is preferably 5% by mass or less in total, based on the total monomers constituting the polymer primary particles, and 3% by mass or less. It is more preferable that
If it exceeds the upper limit, the elastic modulus of the toner at the fixing temperature becomes too high and the toner is not sufficiently softened, resulting in fixing failure.

  Another binder may be copolymerized with the binder resin used in the present invention. Comonomers to be copolymerized include styrenes such as styrene, methylstyrene, chlorostyrene, dichlorostyrene, p-tert-butylstyrene, pn-butylstyrene, pn-nonylstyrene; acrylic acid, methacrylic acid, Methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, hydroxyethyl acrylate, ethyl hexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, methacryl (Meth) acrylic acid esters such as isobutyl acid, hydroxyethyl methacrylate, ethylhexyl methacrylate; acrylamide, N-propylacrylamide, N, N-dimethylacrylamide, N, N-dipropylacrylic acid De, N, N-dibutyl acrylamide, and (meth) acrylamides such as acrylamide. The proportion of these comonomers is preferably 15 wt% or less with respect to the total amount of monomers. When there are too many comonomers, the crystallinity of binder resin will be inhibited.

  The colorant used in the present invention is not particularly limited, and various known colorants suitable for toner can be used. For example, carbon blacks such as furnace black and lamp black; benzidine yellow, benzidine orange, quinoline yellow, acid green, alkali blue, rhodamine, magenta, macalite green, hydroxyanthraquinone, phthalocyanine dyes, quinacridone dyes, dioxanes Synthetic dyes such as dyes, aniline black, azo dyes, naphthoquinone dyes, indigo dyes, nigrosine dyes, phthalocyanine dyes, polymethine dyes, di- and triarylmethane dyes These can be used in combination.

  When the toner of the present invention is used as a full-color toner, an azo pigment (insoluble monoazo, insoluble disazo, condensed azo, etc.) or polycyclic pigment (isoindoline, isoindolinone, selenium) is used for yellow. , Quinophthalone, etc.), and magenta pigments such as azo pigments (azo lake, insoluble monoazo, insoluble disazo, condensed azo, etc.), polycyclic pigments (quinacridone pigments, perylene pigments, etc.) Examples of cyan pigments include phthalocyanine pigments and selenium pigments.

  The combination of the colorants may be appropriately selected in consideration of the hue and the like. I. Pigment yellow 74, C.I. I. Pigment yellow 93, C.I. I. At least one selected from CI Pigment Yellow 155 is C.I. I. Pigment red 238, C.I. I. Pigment red 269, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 48: 2, C.I. I. At least one selected from CI Pigment Red 122 is C.I. I. Pigment blue 15, C.I. I. At least one selected from CI Pigment Blue 15: 3 is preferable as furnace black carbon as the black colorant. It is preferable to use a colorant that contains as little volatile impurities as possible.

The content ratio of the colorant may be an amount sufficient for the obtained toner to form a visible image by development, and is preferably 1 to 20% by mass in the toner base particles, for example, 2 to 15 It is more preferable that it is mass%, and it is especially preferable that it is 3-10 mass% especially. When two or more colorants are used in combination, the total amount is preferably within the above range.
The toner of the present invention is effective when used for any electrostatic image developing toner such as monochrome toner, full-color toner, one-component developer, and two-component developer.

The toner of the present invention may be blended with a charge control agent in order to impart charge amount and charge stability. Conventionally known compounds are used as the charge control agent. Examples thereof include hydroxycarboxylic acid metal complexes, azo compound metal complexes, naphthol compounds, naphthol compound metal compounds, nigrosine dyes, quaternary ammonium salts, and mixtures thereof.
The blending amount of the charge control agent is preferably in the range of 0.1 to 5 parts by weight with respect to 100 parts by weight of the resin.

The toner produced by the toner production method of the present invention preferably contains a wax for imparting releasability. Any wax can be used as long as it has releasability.
Specifically, for example, olefin waxes such as low molecular weight polyethylene, low molecular weight polypropylene and copolymer polyethylene; paraffin wax; ester waxes having a long-chain aliphatic group such as behenyl behenate, montanate ester, stearyl stearate Plant-based waxes such as hydrogenated castor oil carnauba wax; ketones having long-chain alkyl groups such as distearyl ketone; silicones having alkyl groups; higher fatty acids such as stearic acid; long-chain aliphatic alcohols such as eicosanol; glycerin and penta Examples include carboxylic acid esters or partial esters of polyhydric alcohols obtained from polyhydric alcohols such as erythritol and long chain fatty acids; higher fatty acid amides such as oleic acid amides and stearic acid amides; low molecular weight polyesters.

  Among these waxes, in order to improve fixability, the melting point of the wax is preferably 30 ° C. or higher, more preferably 40 ° C. or higher, and particularly preferably 50 ° C. or higher. Moreover, 100 degrees C or less is preferable, 90 degrees C or less is more preferable, and 80 degrees C or less is especially preferable. If the melting point is too low, the wax may be exposed on the surface after fixing, and stickiness may occur. On the other hand, if the melting point is too high, the fixing property at low temperatures may be inferior.

Further, as the wax compound type, it is preferable to use at least one of higher fatty acid ester wax, olefin wax such as copolymer polyethylene, paraffin wax, and silicone wax.
Specific examples of the higher fatty acid ester wax include, for example, behenyl behenate, stearyl stearate, stearate ester of pentaerythritol, glyceride montanate and the like, and fatty acids having 15 to 30 carbon atoms and 1 to 5 valent alcohols. Esters are preferred. Moreover, as an alcohol component which comprises ester, a C10-30 thing is preferable in the case of monohydric alcohol, and a C3-C10 thing is preferable in the case of a polyhydric alcohol.

The silicone wax is not limited as long as it contains a silicon atom in the main chain skeleton of the molecule, for example, an alkyl group such as methyl group, ethyl group, propyl, butyl group, phenyl group, phenol group, styryl group, Examples include organopolysiloxane (dimethylsilicone), organopolymetallosiloxane, organopolysilazane, organopolysilmethylene, organopolysilphenylene, etc. having an aryl group such as a benzyl group in the side chain. These compounds have side chains or molecular ends, for example, amino groups, epoxy groups, mercapto groups, carboxyl groups, hydroxyl groups, alkoxysilyl groups, carbinol groups, alkoxy groups, alkyl groups, aralkyl groups, polyethers, etc. It may be modified, or may be halogenated and modified such as fluorinated or chlorinated. Furthermore, it may be a block copolymer or graft copolymer composed of a chain containing a silicon atom in the main chain skeleton of the molecule and a chain not containing a silicon atom in the main chain skeleton of the molecule.
Among these, dimethylpolysiloxane (dimethylsilicone resin) or modified dimethylpolysiloxane is preferable.
Further, in addition to the linear structure, it may be cyclic or network-like, that is, partially crosslinked.

The above waxes may be used alone or in combination. Further, the melting point of the wax compound can be appropriately selected depending on the fixing temperature for fixing the toner.
The content of the wax in the toner is usually 0.1 to 40 parts by weight, preferably 1 to 40 parts by weight, more preferably 5 to 35 parts by weight, with respect to 100 parts by weight of the binder resin. The amount is particularly preferably 7 to 30 parts by weight.

The melting point of the toner (hereinafter sometimes abbreviated as Tm) is 100 ° C. or less, preferably 90 ° C. or less, more preferably 80 ° C. or less, and further preferably 75 ° C. or less. Moreover, although a minimum is not specifically limited, Preferably it is 30 degreeC or more, More preferably, it is 40 degreeC or more. When Tm exceeds the upper limit, low-temperature fixing may be difficult, and the transparency of the toner may be reduced when fixing the color toner.
On the other hand, when the lower limit range satisfies the preferred range, the toner has excellent storability and the fluidity of the toner does not decrease even after long-term storage. When the upper limit range satisfies the preferable range, it is possible to provide an image having excellent low-temperature fixability and excellent transparency and glossiness of a fixed image.

  The weight-average molecular weight of the binder resin soluble in THF (hereinafter sometimes abbreviated as Mw) is 10,000 or more. If Mw is less than 10,000, hot offset may occur. The upper limit of Mw is not specified, but if it is 100,000 or more, there is a possibility that adhesion between resin fine particles may be insufficient in toner production using the aggregation method.

In the electrostatic charge image developing toner containing the binder resin and the colorant, the storage elastic modulus G ′ (Tm + 30) at the melting point (Tm) + 30 ° C. is 10 Pa ≦ G ′ (Tm + 30) ≦ 10000 Pa. Preferably 20 Pa ≦ G ′ (Tm + 30) ≦ 5000 Pa, more preferably 2 Pa
≦ G ′ (Tm + 60) ≦ 3000 Pa.
Moreover, the storage elastic modulus G ′ (Tm + 60) at the melting point (Tm) + 60 ° C. is 1 Pa ≦ G ′ (Tm + 60) ≦ 5000 Pa. Preferably 20 Pa ≦ G ′ (Tm + 30) ≦ 300
0 Pa, more preferably 2 Pa ≦ G ′ (Tm + 60) ≦ 2000 Pa. By satisfying the above range, low-temperature fixing is possible and good fixing performance with a wide fixing temperature range can be obtained.
On the other hand, if the storage elastic modulus is too higher than the above range, the toner will not be sufficiently softened and fixing to paper will be insufficient. On the other hand, if the storage elastic modulus is too lower than the above range, the toner softened between the paper and the fixing roller is agglomerated and broken to cause a phenomenon (hot offset) that does not release from the fixing roller.

The storage elastic modulus G ′ (25) of the toner at 25 ° C. is G ′ (25) ≧ 1.0 × 10 ⁷ Pa. Preferably it is 5.0 * 10 < ⁷ > Pa or more, More preferably, it is 1.0 * 10 < ⁸ > Pa or more. When the above range is satisfied, the toner is not fused and excellent in storage stability. On the other hand, if outside the above range, blocking tends to occur during storage, which is not preferable.

In the present invention, the ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) of the toner base particles is 1.2 or less, preferably 1.15 or less, more preferably 1. 1 or less.
A toner having a Dv / Dn in the above range has a very sharp particle size distribution, so that a colorant, a charge control agent, and the like are more uniformly distributed and the chargeability is uniform, so that high-precision image formation and latent image are obtained. This is advantageous for image reproducibility.
Next, a toner manufacturing method will be described.

  The method for producing the toner of the present invention is not particularly limited. That is, the toner can be produced by a pulverization method or a polymerization method. When a toner is manufactured by a pulverization method, fine particles are generally easily generated, so that a classification step is necessary. The toner of the present invention is preferably formed with particles in an aqueous medium from the viewpoint of hardly generating fine powder.

As a production method for obtaining a toner in an aqueous medium, a method in which radical polymerization is carried out in an aqueous medium such as a suspension polymerization method or an emulsion polymerization aggregation method (hereinafter abbreviated as “polymerization method”), the obtained toner is “polymerized”. (Abbreviated as “toner”), a chemical pulverization method typified by a melt suspension method, and the like can be preferably used. There is no particular limitation on the method for making the toner have a particle size in the specific range of the present invention. For example, in the production process of the polymerized toner, in the case of the suspension polymerization method, a method in which a high shearing force is applied in the process in which polymerizable monomer droplets are generated, or a dispersion stabilizer or the like is increased.

Among the methods for forming particles in an aqueous medium, the method of producing particles by polymerizing in an aqueous medium is preferable from the viewpoint of hardly generating fine powder, and further, the method of producing particles by an emulsion polymerization aggregation method Is preferred.
Hereinafter, the toner production method of the present invention will be described using the emulsion polymerization aggregation method as a representative example.

When a toner is produced by an emulsion polymerization aggregation method, it usually has a polymerization process, a mixing process, an aggregation process, an aging process, and a washing / drying process. That is, in general, a dispersion containing primary polymer particles obtained by emulsion polymerization, or a dispersion obtained by emulsifying and dispersing a prepolymerized resin in an aqueous medium, a dispersion of a colorant, a flocculant, etc. Are mixed, primary particles in the dispersion are aggregated to obtain particles, and then washed and dried to obtain toner base particles. Further, if necessary, external addition is performed to obtain a product toner.

<Polymerization process>
[Polymer primary particles]
The polymer primary particles used in the emulsion polymerization aggregation method are obtained by emulsion polymerization of a monomer.
In emulsion polymerization, monomers are mixed with water and polymerized in the presence of a polymerization initiator, and the polymerization temperature is usually 50 to 120 ° C, preferably 60 to 120 ° C, more preferably 70 to 100 ° C. If the polymerization temperature is too low, there are problems such that polymerization does not start and emulsified monomer droplets solidify. If the polymerization temperature is too high, the reaction runs out of control and is difficult to control.

  The monomers may be added separately, or a plurality of monomers may be mixed and added in advance. Further, it is possible to change the monomer composition during the monomer addition. The monomer may be added as it is, or may be added as an emulsion prepared by mixing with water or an emulsifier in advance.

Known emulsifiers can be used for emulsion polymerization, but one or more emulsifiers selected from cationic surfactants, anionic surfactants and nonionic surfactants are used in combination. be able to.
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.

Examples of the anionic surfactant include fatty acid soaps such as sodium stearate and sodium dodecanoate, sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and sodium lauryl sulfate.
Nonionic surfactants include, for example, polyoxyethylene dodecyl ether, polyoxyethylene hexadecyl ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl ether, polyoxyethylene sorbitan monooleate ether, monodecanoyl sucrose Etc.

The usage-amount of an emulsifier is 0.2-5 weight part with respect to 100 weight part of polymerizable monomers. If the amount of emulsifier used is too small, emulsification becomes unstable. When the amount of the emulsifier used is too large, the particle size does not grow in the aggregation process. Moreover, 1 type, or 2 or more types, such as partially or fully saponified polyvinyl alcohol, such as polyvinyl alcohol, cellulose derivatives, such as a hydroxyethyl cellulose, can be used together with these emulsifiers as a protective colloid.

  Examples of the polymerization initiator include hydrogen peroxide; persulfates such as potassium persulfate; organic peroxides such as benzoyl peroxide and lauroyl peroxide; 2,2′-azobisisobutyronitrile; Azo compounds such as 2′-azobis (2,4-dimethylvaleronitrile); redox initiators and the like are used. 1 type, or 2 or more types are normally used in the quantity of about 0.1-20 weight part with respect to 100 weight part of polymerizable monomers. Among them, it is preferable that at least part or all of the initiator is hydrogen peroxide or organic peroxides.

Any of the polymerization initiators may be added to the polymerization system before, simultaneously with, or after the addition of the polymerizable monomer, and these addition methods may be combined as necessary.
In the emulsion polymerization, a known chain transfer agent can be used as necessary. Specific examples of such a chain transfer agent include tetrachlorobromomethane, t-dodecyl mercaptan, and 2-mercaptoethanol. , Diisopropylxanthogen, carbon tetrachloride, trichlorobromomethane and the like. The chain transfer agent may be used alone or in combination of two or more, and is used in the range of 5% by mass or less based on the total polymerizable monomer. Moreover, a pH adjuster, a polymerization degree adjuster, an antifoaming agent, etc. can be further mix | blended with a reaction system suitably.

  The volume average diameter (Mv) of the polymer primary particles obtained by emulsion polymerization is usually 0.02 μm or more, preferably 0.05 μm or more, more preferably 0.1 μm or more, and usually 3 μm or less, preferably 2 μm or less. More preferably, the thickness is 1 μm or less. When the particle size is less than the above range, it may be difficult to control the aggregation rate. When the particle size exceeds the above range, the particle size of the toner obtained by aggregation tends to be large, and a toner having a target particle size can be obtained. It can be difficult.

  In the present invention, the polymer primary particles obtained above are used as a dispersion and subjected to the next step. The solid content concentration of the polymer primary particles in the polymer primary particle dispersion used here is the lower limit. The value is preferably 5% by weight or more, more preferably 10% by weight or more, while the upper limit is preferably 50% by weight or less, more preferably 40% by weight or less. When it is within the above range, it is easy to adjust the aggregation rate of the polymer primary particles empirically in the aggregation step, and as a result, it becomes easy to adjust the particle size, particle shape, and particle size distribution to arbitrary ranges.

[Colorant]
In the emulsion polymerization aggregation method, a dispersion of polymer primary particles and a colorant are mixed to obtain a mixed dispersion, which is then aggregated to form a particle aggregate. The colorant is an emulsifier (the surfactant described above). ) Is preferably dispersed in water and used in a suspension state. The volume median diameter (Mv50) of the colorant particles is preferably 0.01 μm to 3 μm. The amount of the colorant used is usually 1 to 25 parts by weight, preferably 3 to 20 parts by weight, based on 100 parts by weight of the polymer primary particles.

As a method of blending the colorant in the emulsion polymerization aggregation method, usually, a polymer primary particle dispersion and a colorant dispersion are mixed to form a mixed dispersion, and then aggregated to obtain a particle aggregate. The colorant dispersion is preferably obtained in the state of being emulsified in water by a mechanical means such as a sand mill or a bead mill in the presence of an emulsifier. At this time, the colorant dispersion is preferably added with 10 to 30 parts by weight of the colorant and 1 to 15 parts by weight of the emulsifier with respect to 100 parts by weight of water. The particle size of the colorant in the dispersion is monitored while being dispersed, and finally the volume average diameter (Mv) is 0.
. It is good to set it as 01-3 micrometers, and it is good to control to the range of 0.05-0.5 micrometer more suitably. The blending of the colorant dispersion at the time of aggregation is calculated and used so as to be 2 to 10% by mass in the finished toner base particles after aggregation.

[Charge control agent]
When a charge control agent is contained in the toner in the emulsion polymerization aggregation method, the charge control agent is blended with a polymerizable monomer or the like at the time of emulsion polymerization, or is blended in the aggregation process with the polymer primary particles and the colorant. The coalesced primary particles, the colorant, and the like can be blended by a method such as agglomeration and blending after a particle size almost suitable as a toner is obtained. Among these, the charge control agent is preferably emulsified and dispersed in water using an emulsifier, and used as a charge control agent dispersion having a volume average diameter (Mv) of 0.01 μm to 3 μm. The blending of the charge control agent dispersion at the time of aggregation is calculated and used so as to be 0.1 to 5% by mass in the finished toner base particles after aggregation.

[wax]
The toner of the present invention may contain a wax for imparting releasability. The wax is preferably used in the form of an emulsified wax fine particle dispersion previously dispersed in the presence of an emulsifier. The wax is present in the agglomeration step. For this purpose, the wax fine particle dispersion is co-agglomerated with the polymer primary particles and the colorant particles, and the monomer is seed emulsion polymerized in the presence of the wax fine particle dispersion. In some cases, polymer primary particles encapsulating are produced and the colorant particles are aggregated. Among these, in order to uniformly disperse the wax in the toner, it is preferable that the wax fine particle dispersion be present when the above polymer primary particles are formed, that is, when the monomer is polymerized.

  The average particle size of the wax fine particles is preferably 0.01 μm to 3 μm, more preferably 0.1 μm to 2 μm, and particularly preferably 0.3 μm to 1.5 μm. When the average particle size of the wax emulsion is larger than 3 μm, it tends to be difficult to control the particle size during aggregation. Further, when the average particle size of the emulsion is smaller than 0.01 μm, it is difficult to prepare a dispersion.

<Mixing process>
In the mixing step of the present invention, the above-mentioned polymer primary particle dispersion, colorant particle dispersion, charge control agent dispersion and wax fine particle dispersion are prepared as necessary, and these are mixed to obtain a mixed dispersion. obtain. Before the agglomeration step of the present invention, it is preferable from the viewpoint of the uniformity of the composition and the uniformity of the particle diameter to prepare a dispersion in advance and mix them to obtain a mixed dispersion.

  Furthermore, the polymer primary particle dispersion obtained by emulsion polymerization is mixed with a colorant, a charge control agent, a colorant particle dispersion, and if necessary, a charge control agent dispersion and a wax fine particle dispersion, The toner base particles may be obtained by aggregating the primary particles to form core particles, and washing and drying the particles obtained by fusing and adhering resin fine particles and the like.

<Aggregation process>
The polymer primary particle dispersion liquid, the colorant particle dispersion liquid, the charge control agent dispersion liquid, and the mixed dispersion liquid of the wax fine particle dispersion are aggregated in an aggregation process to create a particle aggregate. In this aggregation process, There is a method of performing aggregation by heating. Moreover, you may aggregate by adding electrolyte.
The agglomeration treatment includes a heating method, a method of adding an electrolyte, a method of combining these, and the like, usually in a stirring tank.
When primary particles are agglomerated under stirring to obtain particle agglomerates that are approximately the size of the toner, the particle size of the particle agglomerates is controlled from the balance between the agglomeration force between the particles and the shearing force due to agitation. However, the cohesive force can be increased by the above method.

  Also, when different types of dispersions such as polymer primary particle dispersion, colorant particle dispersion, charge control agent dispersion, wax fine particle dispersion, etc. are mixed, the aggregation rate of the components contained in each dispersion is different. For this reason, in order to perform aggregation uniformly, it is preferable to add and mix continuously or intermittently over a certain period of time. Since the suitable time required for the addition varies depending on the amount of the dispersion to be mixed, the solid content concentration, and the like, it is preferable to adjust appropriately.

  In the present invention, the concentration of the electrolyte and the emulsifier in the aggregation step is appropriately combined so that preferable aggregate growth occurs at a temperature equal to or higher than the melting point of the polymer primary particles. The role of the electrolyte in the agglomeration process is to shield the electrostatic repulsive force of polymer primary particles and colorant particles dispersed as fine particles, including wax fine particles and charge control agent particles in some cases. It is thought to be caused to wake up. On the other hand, it is considered that the role of the emulsifier is to adsorb to the surface of each particle and to provide electrostatic repulsive force and steric repulsive force between the particles to stabilize dispersion. The cohesive force between these particles is determined by the balance between the electrolyte concentration and the emulsifier concentration. When the electrolyte concentration and the emulsifier concentration are balanced, an agglomerated particle dispersion can be obtained, but if the balance is not achieved, macroagglomerates may be formed or the agglomerates may not be aggregated.

  However, when these concentrations are adjusted so that the growth of aggregates occurs at a low temperature at which the polymer primary particles are solid, the temperature exceeds the melting point of the polymer primary particles in order to coalesce the aggregates. As soon as the amount is increased, the aggregates further aggregate to form a large lump. On the other hand, when an emulsifier is further added to stabilize the aggregated material below the melting point, the aggregated particles are reversibly dispersed in the particles before aggregation. This difficulty is essentially due to the fact that the adhesion between the polymer primary particles changes discontinuously with the melting point of the polymer as a boundary, and the conventionally used amorphous polymer primary is used. It was not seen when particles were used.

In the present invention, in order to achieve preferable aggregate growth using crystalline polymer primary particles, an electrolyte concentration and an emulsifier that balances weak dispersion instability and addition-reverse interparticle adhesion force above the melting point. The inventors discovered that a combination of concentrations is necessary, and further found a process in which aggregated particles grow gradually while being united by a combination of concentrations that balance.
Appropriate electrolyte and emulsifier concentrations should be adjusted in advance below the melting point of the polymer primary particles. When the electrolyte is added after the dispersion of the polymer primary particles is brought to the melting point or higher, rapid aggregation occurs in a region where the electrolyte concentration is unevenly high, making it difficult to control the particle size.

As an electrolyte in the case of performing aggregation by adding an electrolyte, either an organic salt or an inorganic salt may be used. Specifically, NaCl, KCl, LiCl, Na ₂ SO ₄ , K ₂ SO ₄ , Li ₂ SO ₄ may be used. Inorganic salts having a monovalent metal cation such as CH ₃ COONa, C ₆ H ₅ SO ₃ Na; inorganic salts having a divalent metal cation such as MgCl ₂ , CaCl ₂ , MgSO ₄ , CaSO ₄ , ZnSO ₄ ; Examples thereof include inorganic salts having a trivalent metal cation such as Al ₂ (SO ₄ ) ₃ and Fe ₂ (SO ₄ ) ₃ . Among these, when an inorganic salt having a divalent or higher polyvalent metal cation is used, the agglomeration rate is increased, which is preferable in terms of productivity.

  The amount of the electrolyte used varies depending on the type of electrolyte, target particle size, and the like, but is usually 0.1 to 20 parts by weight, preferably 0.2 to 15 parts per 100 parts by weight of the solid component of the mixed dispersion. Part by weight, more preferably 0.5 to 10 parts by weight. When the amount used is less than the above range, the particle size growth due to agglomeration is delayed, and fine powder of 1 μm or less remains after the particle size growth, or the average particle size of the obtained particle aggregate does not reach the target particle size. If the above range is exceeded, rapid agglomeration tends to occur, making it difficult to control the particle size, resulting in the formation of macro agglomerates.

  In addition, it is preferable that the electrolyte is added not intermittently but intermittently or continuously over a certain period of time. The addition time varies depending on the amount used, but is preferably added over 0.5 minutes. Usually, when an electrolyte is added, abrupt aggregation starts as soon as the electrolyte is added, so that there is a tendency that a large amount of polymer primary particles, colorant particles, aggregates, and the like left behind in the aggregation remain. These are considered to be one of the sources of fine powder. According to the above operation, uniform agglomeration can be performed without abrupt agglomeration, so that generation of fine powder can be prevented.

  When the emulsifier is blended in advance before the start of aggregation, the blending amount is preferably 0.1 parts by weight or more, more preferably 0.2 parts by weight or more, further preferably 100 parts by weight of the solid component of the mixed dispersion. It is 0.5 parts by weight or more, preferably 20 parts by weight or less, more preferably 15 parts by weight or less, and still more preferably 10 parts by weight or less. It is important that both the electrolyte and the emulsifier are prepared at appropriate concentrations before the start of agglomeration, and then sufficiently stirred before raising the temperature to be mixed homogeneously with the primary particle dispersion. If the temperature is raised without performing sufficient stirring, the agglomeration rapidly proceeds partially above the melting point and coarse particles are generated.

  In the emulsion polymerization aggregation method, in order to increase the stability of the particle aggregate obtained by aggregation, an additional emulsifier or pH adjuster is added as a dispersion stabilizer to reduce the cohesive force between the particles, thereby reducing the toner base particles. After stopping the growth, it is preferable to add an aging step for causing fusion between the aggregated particles.

  In order to increase the stability of the aggregate, the amount of the emulsifier added is preferably 0.05 parts by weight or more, more preferably 0.1 parts by weight with respect to 100 parts by weight of the solid component of the mixed dispersion. Part or more, more preferably 0.2 part by weight or more, preferably 10 parts by weight or less, more preferably 5 parts by weight or less, still more preferably 3 parts by weight or less. After the aggregation process, before the completion of the ripening process, by adding an emulsifier or by increasing the pH value of the flocculation liquid, aggregation of the particle aggregates aggregated in the aggregation process can be suppressed. The generation of coarse particles in the toner can be suppressed.

  When adding a pH adjuster, it is not particularly limited as long as it can be dissolved in water and the pH can be adjusted, but those capable of adjusting a pH of less than 5 to a range of 5 to 7 are preferred. Specifically, for example, sodium hydroxide, sodium carbonate, sodium hydrogen carbonate, sodium acetate, aqueous ammonia, amine compounds, or the like, or those obtained by changing these sodium salts to alkali metal salts such as potassium salts, etc. .

In the agitation of the mixed dispersion liquid in the aggregation step, the particle size distribution can be sharpened by controlling the particle size within a specific range by reducing the stirring rotation speed, that is, by reducing the shearing force by stirring. The method of lowering the stirring rotation speed in the aggregation step is preferably employed when the crystalline polymer primary particles that have been completely melted are gradually adhered and aggregated with weak interparticle attraction.
When the method of reducing the stirring rotation speed is used for the amorphous polymer primary particles, the cohesive force becomes too strong, which may lead to an increase in particle diameter.

As an example, the toner having a specific particle size distribution according to the present invention can be obtained by the above-described method. More specifically, the particle size distribution can be adjusted by the degree to which the rotational speed is decreased. For example, if the stirring rotation speed is slowly changed over a certain period of time, a sharp toner can be provided, and a toner having a specific particle size distribution of the present invention can be obtained. By changing the rotation speed of stirring while monitoring the aggregated particle diameter, precise control of the aggregated particle diameter becomes possible. Since the aggregation step in the present invention is non-reversible, the aggregation can be stopped or delayed by increasing the rotation speed. Further, in order to completely stop the aggregation, it is advisable to add an emulsifier.

<Aging process>
In the emulsion polymerization aggregation method, heat treatment is performed to increase the stability of the particle aggregate (toner base particles) obtained in the aggregation step. By this heat treatment, the polymer primary particles in the aggregate are fused and integrated, and the shape of the toner base particles as the aggregate is close to a sphere. The particle aggregate before the aging step is considered to be an aggregate due to electrostatic or physical aggregation of the polymer primary particles, but after the aging step, the polymer primary particles constituting the particle aggregate are fused to each other. In addition, the shape of the toner base particles can be made nearly spherical.

The temperature of the aging step is preferably not less than the melting point of the binder resin as the polymer primary particles, more preferably not less than 5 ° C higher than the melting point, and preferably not more than 200 ° C higher than the melting point, more preferably The temperature is 150 ° C. or higher than the melting point.
The time required for the aging step varies depending on the shape of the target toner, but it is not lower than the melting point of the polymer constituting the polymer primary particles and is usually maintained for 0.1 to 5 hours, preferably 1 to 3 hours. Is desirable.

<Washing and drying process>
The particle aggregate obtained through each of the above steps is subjected to solid-liquid separation according to a known method, the particle aggregate is recovered, then washed as necessary, and then dried. Toner mother particles can be obtained.

<External addition process>
The toner of the present invention may be one in which a known external additive is blended on the surface of the toner base particles in order to control fluidity and developability. External additives include metal oxides and hydroxides such as alumina, silica, titania, zinc oxide, zirconium oxide, cerium oxide, talc and hydrotalcite, titanium such as calcium titanate, strontium titanate and barium titanate. Examples thereof include acid metal salts, nitrides such as titanium nitride and silicon nitride, carbides such as titanium carbide and silicon carbide, and organic particles such as acrylic resins and melamine resins, and a plurality of them can be combined. Among these, silica, titania, and alumina are preferable, and those that have been surface-treated with, for example, a silane coupling agent or silicone oil are more preferable. The average primary particle diameter is preferably in the range of 1 to 500 nm, more preferably in the range of 5 to 100 nm. It is also preferable to use a combination of a small particle size and a large particle size in the particle size range. The total amount of the external additive is preferably in the range of 0.05 to 10 parts by weight, more preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of the toner base particles.

  Thus, the toner for developing an electrostatic charge image obtained by the production method of the present invention usually has a volume average particle diameter (Dv) of 3 to 8 μm, preferably 4 to 8 μm, and more preferably 4 to 7 μm. If the volume average particle size is too large, it is not suitable for high-resolution image formation, and if it is too small, handling as a powder becomes difficult.

  The toner circularity is preferably an average circularity of 0.9 to 1.0, more preferably 0.93 to 0.98, and particularly preferably 0.94 to 0.98. If the circularity is less than the above range, the transfer efficiency may be poor and the dot reproducibility may be reduced. If the circularity exceeds the above range, untransferred toner remaining on the photoreceptor may not be completely scraped off by the blade and cause image defects. There is.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist. In the following examples, “parts” means “parts by weight”.

[Measurement method of binder resin molecular weight]
The molecular weight in this example was measured under the following conditions. The binder resin is uniformly dispersed and dissolved in a tetrahydrofuran (THF) solvent, and then THF-insoluble matter is removed by suction filtration with a Buchner funnel in which a fine filter layer is formed with Celite. Next, the molecular weight distribution of the filtered THF soluble matter is measured by GPC under the following conditions, and the molecular weight is obtained from a calibration curve prepared from several types of monodisperse polystyrene standard samples.
Solvent THF
Sample flow rate 1ml / min
Sample concentration 0.4gr / dl · THF
Sample flow rate Solution 8mg
Confirmation of reliability Confirm by confirming that Mw / Mn of NBS706 polystyrene standard sample (Mw = 28.8 × 104, Mn = 13.7 × 104, Mw / Mn = 2.11) is 2.11 ± 0.10. .

[Method for measuring storage modulus]
The storage elastic modulus measurement in this example was performed using a rotary rheometer VAR50 (Rheologicalka). Using a parallel plate, the temperature increase was measured from 25 ° C. to 180 ° C. at 4 ° C./min at an initial gap of 0.8 mm, an angular frequency of 1 Hz, and a stress strain of 1%. The plate diameter was 20φ. In the range of G ′> 1000000 Pa, the gap was set to be variable by the auto tension function.

[Measurement method of toner melting point (Tm)]
The value (ΔG ′ / ΔT) of the storage elastic modulus G ′ (ΔG ′) that changes with a temperature change (ΔT) of 1 K was 10 (Pa / K) or more. Moreover, said method was used for the measuring method of storage elastic modulus.

[Measurement method of volume average particle diameter (Dv) and number average particle diameter (Dn)]
Measurement of polymer primary particles “Microtrac UPA (ultra particle analyzer)” manufactured by Nikkiso Co., Ltd.
(Abbreviated as “PA”), and defined as a value measured by a conventional method according to the instruction manual of the apparatus.
Measurement of Toner Measurement was performed using a Beckman Coulter Multisizer II (aperture diameter 100 μm, hereinafter abbreviated as “Multisizer”), using the same Isoton II as a dispersion medium and dispersing the dispersion to a concentration of 0.03%.

[Measurement method of circularity]
In the present invention, the “average circularity” is determined by dispersing toner base particles in a dispersion medium (Isoton II, manufactured by Beckman Coulter, Inc.) so as to be in the range of 5720 to 7140 particles / μL. (FPIA2100, manufactured by Toa Medical Electronics Co., Ltd.) is measured under the following apparatus conditions, and the value is defined as “average circularity”. In the present invention, the same measurement is performed three times, and an arithmetic average value of three “average circularity” is adopted as the “average circularity”.
・ Mode: HPF
-HPF analysis amount: 0.35 μL
-HPF detection number: 2000-2500

The following is measured by the above device and automatically calculated and displayed in the above device, and “circularity” is defined by the following formula.
[Circularity] = [Perimeter of a circle with the same area as the projected particle area] / [Perimeter of projected particle image]
And 2000-2500 which is the number of HPF detection is measured, and the arithmetic average (arithmetic mean) of the circularity of each individual particle is displayed on the apparatus as “average circularity”.

[Example 1]
<Preparation of monomer dispersion A>
Stearyl acrylate (Tokyo Kasei Co., Ltd., Tm (28 ° C.)) 200 parts, 1-9 nonanediol diacrylate 0.6 parts, 20% anionic surfactant aqueous solution (Daiichi Kogyo Seiyaku Co., Ltd., Neogen S20A) 11 parts 789 parts of demineralized water was heated to 50 ° C. and stirred for 5 minutes with a homogenizer. Next, this dispersion was heated to 90 ° C. and emulsified for 10 minutes under a pressurized condition of about 200 MPa using a homogenizer (manufactured by Gorin, 15-M-8PA type).

<Preparation of polymer primary particle dispersion A>
A reactor equipped with a stirrer (three blades), a heating / cooling device, a concentrating device, and a raw material / auxiliary charging device was charged with 500 parts by weight of monomer dispersion A, and the temperature was raised to 90 ° C. under nitrogen flow while stirring. Warm up. After 120 minutes, the following chain transfer agent was added all at once. Thereafter, the following initiator aqueous solution mixtures were simultaneously added at a constant rate from 30 minutes after addition of the chain transfer agent to 240 minutes after stirring. As the emulsifier, Neogen SC, a 65.8% sodium dodecylbenzenesulfonate aqueous solution manufactured by Daiichi Kogyo Seiyaku Co., Ltd., diluted to 20% with demineralized water (hereinafter abbreviated as 20% DBS aqueous solution) was used.
[Chain transfer agent]
1.0 part of tetrachlorobromomethane
[Initiator aqueous solution]
8% aqueous hydrogen peroxide solution 15.5 parts 8% L (+)-ascorbic acid aqueous solution 15.5 parts

  After completion of the polymerization reaction, the mixture was cooled to obtain a milky white polymer primary particle dispersion A. The volume average particle diameter measured by Microtrac UPA was 240 nm. The weight average molecular weight of the polymer solid obtained by freeze-drying the polymer primary particle dispersion A was 148,600, and the number average molecular weight was 26,500. The melting point was 48 ° C.

<Preparation of Colorant Dispersion A>
C. I. 15 parts of Pigment Blue, 1 part of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen SC), 5 parts of a nonionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neugen EA80), 80 parts of water, sand grinder mill To obtain a colorant dispersion A. The volume average particle diameter measured by Microtrac UPA was 150 nm.

<Manufacture of developing toner 1>
Polymer primary particle dispersion A 100 parts (as solid content)
Colorant dispersion A 3.6 parts (as solids)
20% DBS aqueous solution 4.0 parts (as solid content)
3.5 parts of 5% MgSO4 aqueous solution (as solid content)
[Aggregation stop agent]
20% DBS aqueous solution 0.3 parts (as solid content)

Using each of the above components, a toner was produced by the following procedure.
Polymer primary particle dispersion A and colorant dispersion A are charged into a reactor (2 liters, double helical blade with baffle), mixed uniformly, and then 5% MgSO4 aqueous solution is added at a constant rate over 5 minutes. And mixed uniformly. The resulting mixture was heated to 43 ° C. while stirring at a stirring speed of 400 rpm, and a 20% DBS aqueous solution was added at a constant rate over 1 minute. While stirring as it was, the temperature was raised to 70 ° C., and after 1 hour, the stirring rotation speed was changed to 300 rpm. Further, after 1.5 hours, the rotational speed was changed to 250 rpm. After 40 minutes, the rotation speed was changed to 200 rpm. Further, after 15 minutes, the rotational speed was changed to 170 rpm. Further, after 20 minutes, the rotation speed was changed to 150 rpm. Further, after 35 minutes, the rotational speed was changed to 140 rpm. Further, after 10 minutes, the rotation speed was changed to 130 rpm. After being held for 10 minutes, the volume average particle diameter of the toner measured with a Coulter counter was 7.05 μm and the number average particle diameter was 6.72 μm. In order to stop the aggregation, the rotation speed was changed to 300 rpm. Further, after 30 minutes, in order to reliably stop the aggregation, 0.3 part of 20% DBS aqueous solution was added with the rotational speed kept unchanged. Stirring was continued for 50 minutes as it was, and then cooled to room temperature. At this time, the volume average particle diameter of the toner measured with a Coulter counter was 7.07 μm, the number average particle diameter was 6.74 μm, and Dv / Dn was 1.049. In the above process, after the temperature is raised to 70 ° C., the particle diameter number distribution of the toner measured by a Coulter counter at each time shown in Table 1 is shown in FIG. FIG. 1 shows that the particle size of the aggregate grows and the distribution becomes sharper by changing the rotation speed.
Thereafter, the slurry obtained by cooling was subjected to suction filtration using a Kiriyama funnel. Thereafter, suction filtration was continued while adding washing water until the electrical conductivity of the filtrate reached 2 μS / cm. Toner 1 was obtained by drying the toner cake obtained by filtering this.
The melting point of the toner was 48 ° C., the storage elastic modulus at Tm + 30 ° C. was G ′ (Tm + 30) = 48 Pa, and the storage elastic modulus at Tm + 60 ° C. was G ′ (Tm + 60) = 26 Pa.
Further, since the toner is in a solid state, the storage elastic modulus at 25 ° C. can be measured only up to the upper limit of the measuring device. The upper limit value was 1.2 × 10 ⁷ Pa.

[Example 2]
<Manufacture of developing toner 2>
The same procedure was followed until the temperature of the developing toner 1 was raised to 70 ° C. while stirring at a stirring speed of 400 rpm. After the temperature was raised to 70 ° C., the speed was changed to 300 rpm after 10 minutes, further changed to 200 rpm after 20 minutes, and stirring was continued for 15 minutes. At this time, the volume average particle diameter of the toner is 7.01 μm, the number average particle diameter is 6.10 μm, Dv / Dn is 1.149, and the circularity is 0.952. Thereafter, the rotational speed was changed to 400 rpm, and xx parts of a 20% DBS aqueous solution were added. Stirring was continued for 1 hour as it was, followed by cooling. At this time, the volume average particle diameter of the toner measured by a Coulter counter is 7.44 μm, the number average particle diameter is 6.55 μm, Dv / Dn is 1.136, and the circularity is 0.978.
Met.
The slurry obtained by cooling was suction filtered using a Kiriyama funnel. Thereafter, suction filtration was continued while adding washing water until the electrical conductivity of the filtrate reached 2 μS / cm. Toner 2 was obtained by drying the toner cake obtained by filtering this.
The melting point of the toner was 48 ° C., the storage elastic modulus at Tm + 30 ° C. was G ′ (Tm + 30) = 47 Pa, and the storage elastic modulus at Tm + 60 ° C. was G ′ (Tm + 60) = 28 Pa.
The change of the storage elastic modulus with respect to the temperature of the toner 2 is shown in FIG. This result shows that the fixing property at a low temperature is good and the fixing temperature range is wide.
Further, since the toner is in a solid state, the storage elastic modulus at 25 ° C. can be measured only up to the upper limit of the measuring device. The upper limit value was 1.2 × 10 ⁷ Pa.

[Comparative Example 1]
<Manufacture of developing toner 3>
When the developing toner 3 was manufactured in exactly the same procedure except that the 5% MgSO 4 aqueous solution was 2.0 parts as a solid component among the components in the development of the developing toner 1, the toner particle diameter did not grow. .

[Comparative Example 2]
<Manufacture of developing toner 4>
The developing toner 4 was manufactured in exactly the same procedure except that the 5% MgSO 4 aqueous solution was 7.0 parts in solid content among the components in the manufacturing of the developing toner 1, and the polymer primary particles and the colorant were Aggregates into large lumps.

[Comparative Example 3]
<Manufacture of developing toner 5>
The developing toner 5 was manufactured in exactly the same procedure except that the 20% DBS aqueous solution was 2.0 parts as a solid component among the components in the manufacturing of the developing toner 1, and the polymer primary particles and the colorant were Aggregates into large lumps.

[Comparative Example 4]
<Manufacture of developing toner 6>
When developing toner 6 was manufactured in exactly the same procedure except that the component of 20% DBS aqueous solution was 7.0 parts as a solid content in the components of manufacturing developing toner 1, toner particle diameter did not grow. .

Claims (10)

  In the toner for developing an electrostatic charge image containing a binder resin and a colorant, the binder resin is a vinyl crystalline resin, and a ratio (Dv) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) of the toner. / Dn) is a toner for developing electrostatic images, wherein the toner is 1.2 or less.   The toner for developing an electrostatic charge image according to claim 1, wherein a ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) of the toner is 1.1 or less.   The toner for developing an electrostatic charge image according to claim 1, wherein a melting point (Tm) of the toner satisfies Tm ≦ 100 ° C.   4. The electrostatic image developing toner according to claim 1, wherein the toner has a melting point (Tm) of Tm ≧ 40 ° C.   5. The electrostatic charge image developing toner according to claim 1, wherein the weight-average molecular weight (Mw) of the THF-soluble component of the binder resin is Mw ≧ 10000.   6. The electrostatic image developing toner according to claim 1, wherein the binder resin has an alkyl group in a side chain of a monomer constituting the binder resin.   7. The electrostatic image developing toner according to claim 1, wherein the colorant is cyan. In an electrostatic charge image developing toner containing a binder resin and a colorant, the storage elastic modulus at the melting point (Tm) + 30 ° C. of the toner is G ′ (Tm + 30), and the storage elastic modulus at the melting point of the toner + 60 ° C. is G ′ (Tm + 60). When satisfying the conditions of the following formulas (1) and (2),
10 Pa ≦ G ′ (Tm + 30) ≦ 10000 Pa (1)
1 Pa ≦ G ′ (Tm + 60) ≦ 5000 Pa (2)
A toner for developing electrostatic images, wherein a ratio (Dv / Dn) of a volume average particle diameter (Dv) to a number average particle diameter (Dn) of the toner is 1.2 or less. The toner for developing an electrostatic charge image according to claim 1, wherein the storage elastic modulus G ′ (25) at 25 ° C. of the toner is G ′ (25) ≧ 1.0 × 10 ⁷ Pa.   10. The electrostatic image developing toner according to claim 1, which is produced by an emulsion aggregation method.

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