JP2011123423A - Capsule toner and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide capsule toner hardly causing a decrease in fluidity of a developer without spoiling low temperature fixability and hot offset resistance, and to develop a method for producing the toner. <P>SOLUTION: The capsule toner comprises core particles (A) containing a colorant and a polyester resin (a) and a shell layer covering the surface of each particle, wherein the shell layer contains a higher α-olefin polymer having a melting point in the range from 55°C to 70°C, obtained by polymerizing α-olefins having 16 or more carbon atoms and a polyester resin (B) having a glass transition point in the range from 50°C to 65°C. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a capsule toner used in an electrophotographic image forming apparatus and a method for manufacturing the same.

  An image forming apparatus that forms an image using an electrophotographic system includes a photoconductor, a charging unit, an exposure unit, a developing unit, a transfer unit, and a fixing unit.

  The charging unit charges the surface of the photoreceptor, and the exposure unit irradiates the charged photoreceptor surface with signal light to form an electrostatic latent image corresponding to image information. The developing means supplies toner in the developer to the electrostatic latent image formed on the surface of the photoconductor to form a toner image, and the transfer means transfers the toner image formed on the surface of the photoconductor to a recording medium. Further, the fixing unit fixes the transferred toner image on the recording medium.

The toner is resin particles that are granulated by dispersing a colorant or wax in a binder resin, and the toner alone is used as a one-component developer or mixed with a carrier and used as a two-component developer.
With the trend of energy saving in recent years, binder resins and low melting point waxes that melt at a lower temperature tend to be used so that toner particles can be fixed to a recording medium at a lower temperature. The toner corresponding to such low-temperature fixing has a drawback that it easily aggregates due to frictional heat generated in the developing device.

To overcome this drawback, there is a capsule toner in which a coating layer is provided on the surface of the toner and encapsulated to make it difficult to aggregate against frictional heat generated in the developing device.
For example, Patent Document 1 (Japanese Patent Application Laid-Open No. 2002-229251) discloses that a core layer containing Fischer-Tropsch wax, a colorant, and a binder resin as a release agent has a glass transition temperature higher than that of the binder resin. Capsule toners coated with a polymer shell layer are described.
However, the capsule toner whose surface is covered with a shell layer has a drawback that high temperature offset is likely to occur because the wax is difficult to ooze onto the toner surface.

For this drawback, a capsule toner in which wax is present on the toner surface is known.
For example, Patent Document 2 (Japanese Patent Laid-Open No. 2005-91706) discloses a core layer formed by agglomerating and fusing first resin particles and a colorant, and second resin particles on the surface of the core layer. In a toner having a core-shell structure composed of an agglomerated and fused shell layer, offset resistance is improved by incorporating a first wax and a second wax in the core layer and the shell layer, respectively.

JP 2002-229251 A JP 2005-91706 A

  However, when a wax having a low melting point (for example, 80 ° C. or less) is exposed on the toner surface, the flowability of the developer becomes extremely high when the temperature of the developer rises due to frictional heat when being stirred and conveyed in the developing device. May decrease. As a result, there is a problem that a sufficient amount of developer cannot be supplied from the developing roller to the photosensitive drum, and the image density is lowered.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a capsule toner that does not easily cause a decrease in developer fluidity without impairing low-temperature fixability and hot offset resistance, and a method for producing the same.

  As a result of intensive research, the present inventors have found a capsule toner in which core particles containing a colorant and a polyester resin are coated with a shell layer containing an α-olefin polymer having 16 or more carbon atoms and a polyester resin. The present inventors have found that the above problems can be solved and have completed the present invention.

That is, according to the present invention, in a capsule toner having a core particle (A) containing at least a colorant and a polyester resin (a) and a shell layer covering the surface of the core particle,
The shell layer is a higher α-olefin polymer having a melting point of 55 ° C. to 70 ° C. obtained by polymerizing an α-olefin having 16 or more carbon atoms, and a glass transition point of 50 ° C. to 65 ° C. A capsule toner comprising a polyester resin (B) is provided.

    The core particle (A) includes a polymer of phthalic acid and glycol as the polyester resin (a), and the shell layer includes a polymer of phthalic acid, glycol and bisphenol A alkoxylate as the polyester. A capsule toner is provided.

  The core particle (A) contains a polymer of phthalic acid or phthalic acid ester and ethylene glycol or propylene glycol as the polyester resin (a), and the shell layer has phthalic acid or phthalic acid ester as the polyester resin (B), There is provided such a capsule toner comprising a polymer of ethylene glycol or propylene glycol and bisphenol A methoxylate, bisphenol A ethoxylate or bisphenol A propoxylate.

  According to the present invention, the core particle (A) contains a polymer of phthalate and glycol as the polyester resin (a), and the shell layer contains phthalate, glycol and bisphenol A derivative as the polyester resin (B). There is provided such a capsule toner comprising a polymer.

  According to the invention, the core particle (A) contains a polymer of dimethyl terephthalate, dimethyl isophthalate, 5-sodium sulfodimethyl isophthalate, ethylene glycol and propylene glycol as the polyester resin (a), and the shell There is provided the above capsule toner, wherein the layer comprises a polymer of dimethyl terephthalate, dimethyl isophthalate, ethylene glycol and bisphenol A ethoxylate as the polyester resin (B).

In addition, according to the present invention, there is provided the capsule toner in which the shell layer includes an α-olefin polymer having 16 to 28 carbon atoms.
Further, according to the present invention, there is provided the capsule toner in which the shell layer contains a polymer of α-olefin having 22 and 24 carbon atoms.
Further, according to the present invention, there is provided the capsule toner in which the shell layer contains the α-olefin polymer in a range of 100: 5 to 100: 20 with respect to the polyester resin (B).

In addition, according to the present invention, there is provided the capsule toner in which the core particles (A) further contain petroleum wax, and the shell layer does not contain petroleum wax.
In addition, according to the present invention, there is provided the capsule toner in which the core particles (A) have a number average particle diameter of 2 μm to 10 μm and the capsule toner has a number average particle diameter of 3 μm to 11 μm.

Furthermore, according to the present invention, a step of producing an aqueous dispersion of core particles (A) having a number average particle diameter of 2 μm to 10 μm containing at least a colorant and a polyester resin (a);
Producing an aqueous dispersion of polyester resin particles (B) having a number average particle diameter of 0.05 μm to 0.5 μm;
Higher α-olefin polymer particles having a number average particle size of 0.05 μm to 0.5 μm, including an α-olefin polymer having a melting point of 55 ° C. to 70 ° C., obtained by polymerizing an α-olefin having 16 to 28 carbon atoms Producing an aqueous dispersion of (C);
The aqueous dispersion of the core particles (A), the aqueous dispersion of the polyester particles (B), and the aqueous dispersion of the higher α-olefin polymer particles (C) are mixed, and the resulting mixture is heated. Or the surface of the core particles (A) is coated with the polyester resin particles (B) and the higher α-olefin polymer particles (C) by adding a flocculant to the obtained mixed liquid. A step of forming coated particles;
And a smoothing step of heating the coated particles. A method for producing a capsule toner is provided.

According to the present invention, the melting point of the α-olefin polymer is higher than the glass transition point of the polyester particles (B),
The manufacturing method is provided in which the heating temperature of the coated particles in the smoothing step is not less than the glass transition point of the polyester particles (B) and not more than the melting point of the α-olefin polymer.

Further, according to the present invention, the core particle (A) includes a petroleum wax having a melting point higher than the glass transition point of the polyester particle (B),
The manufacturing method is provided in which the heating temperature of the coated particles in the smoothing step is not less than the glass transition point of the polyester particles (B) and not more than the melting point of the petroleum wax.

  Since the capsule toner according to the present invention contains a hard α-olefin polymer having a low melting point in the outermost shell layer of the toner particles, the flow of the developer is not impaired without impairing the low-temperature fixability and the hot offset resistance. Capsule toner that can suppress deterioration in properties can be obtained.

Further, the capsule toner according to the present invention can suppress the decrease in the fluidity of the developer over a long period of time because the α-olefin polymer is difficult to be detached from the shell layer.
Further, the capsule toner according to the present invention includes a petroleum wax that melts at a low temperature in the core particle of the toner, so that the low-temperature fixability can be improved without reducing the fluidity of the toner.

  In addition, the capsule toner according to the present invention includes an α-olefin polymer having optimum hardness and melting point as a release agent in the shell layer which is the outermost layer of the toner particles, so that low temperature fixability and hot offset resistance are obtained. The effect of having a good balance can be obtained with respect to the prevention of deterioration of the flowability of the developer and the developer.

  In the capsule toner according to the present invention, since the higher α-olefin polymer particles (C) are held in the shell layer together with the highly adhesive polyester particles (B), they are difficult to be separated in the smoothing step. Therefore, a decrease in developer fluidity can be suppressed over a long period of time without impairing the low-temperature fixability and hot offset resistance.

  In the capsule toner according to the present invention, the petroleum-based wax is held inside the shell layer without being eluted from the core particles in the smoothing step. A decrease in developer fluidity can be suppressed over a long period of time without impairing fixability and hot offset resistance.

  Furthermore, according to the present invention, since the outermost shell layer of the core particle containing the colorant and polyester contains a hard α-olefin polymer having a low melting point, the low-temperature fixability and hot offset resistance are impaired. In addition, it is possible to provide a method for producing a capsule toner that can suppress a decrease in the fluidity of the developer.

It is a figure which shows an example of the manufacturing process of the capsule toner of this invention.

  The present invention is a capsule toner having a shell layer on the surface of core particles. Hereinafter, a method for producing the capsule toner and materials constituting the capsule toner will be sequentially described.

[Component materials of capsule toner]
The capsule toner according to the present invention is an α-olefin having a melting point of 55 to 70 ° C. obtained by polymerizing an α-olefin having 16 to 28 carbon atoms as a core particle (A) containing at least a colorant and a polyester resin (a). It is characterized by being covered with a shell layer containing a polymer and a polyester resin (B) having a glass transition point of 50 to 65 ° C.

<Colorant>
As the colorant aqueous dispersion used when the core particles (A) are prepared from the aqueous dispersion of resin particles, the colorant is stirred together with a surfactant with a stirrer, so that the number average particle diameter is 0.3 μm or less. Emulsified and dispersed can be used. As the colorant, known ones can be used, and there is no particular limitation except for a water-soluble dye that does not aggregate even when a flocculant is added.

As a colorant for yellow toner, CI Pigment Yellow 1, 3, 4, 5, 6, 12, 13, 14, 15, 16, 17, 18, 24, 55, 65, 73, 74, 81, 83, 87, 93, 94, 95, 97, 98, 100, 101, 104, 108, 109, 110, 113, 116, 117, 120, 123, 128, 129, 133, 138, 139, 147, 151, 153, 154, 155, 156, 168, 169, 170, 171, 172, 173, 180 and 185.
CI pigment yellow 17 (disazo), 74 (monoazo), 155 (condensed azo), and 180 (benzimidazolone) are particularly preferable.

Magenta toner colorants include CI Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 15, 17, 18, 22, 23, 31, 37, 38, 41, 42, 48: 1, 48: 2, 48: 3, 48: 4, 49: 1, 49: 2, 50: 1, 52: 1, 52: 2, 53: 1, 53: 3, 54, 57: 1, 58: 4, 60: 1, 63: 1, 63: 2, 64: 1, 65, 66, 67, 68, 81, 83, 88, 90, 90: 1, 112, 114, 115, 122, 123, 133, 144, 146, 147, 149, 150, 151, 166, 168, 170, 171, 172, 174, 175, 176, 177, 178, 179, 185, 187, 188, 189, 190, 193, 194, 202, 208, 20 9, 214, 216, 220, 221, 224, 242, 243, 243: 1, 245, 246 and 247.
In particular, CI Pigment Red 48: 1 (barium red), 48: 2 (calcium red), 48: 3 (strontium red), 48: 4 (manganese red), 53: 1 (lake red), 57: 1 (brilliant carmine), 122 (quinacridone magenta) and 209 (dichloroquinacridone red) are preferred.

As a colorant for cyan toner, phthalocyanine-based CI Pigment Blue 1, 2, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 15, 16, 17: 1, 27 , 28, 29, 56, 60, 63 and the like.
In particular, CI Pigment Blue 15: 3 (phthalocyanine blue G), 15 (phthalocyanine blue R), 16 (metal-free phthalocyanine blue), and 60 (indanthrone blue) are preferable.

  Carbon black produced by various methods can be used as the colorant for the black toner.

  The colorant of the present invention can be dispersed in water by using a surfactant or the like. In particular, the colorant aqueous dispersion and the sulfonic acid described below are used by using an aggregating agent having a divalent or higher valent metal ion. When making the core particle (A) from an aqueous dispersion of resin particles having a salt, it is desirable from the viewpoint of uniform particle size control that the cationic surfactant is not substantially contained as a colorant dispersant.

One colorant may be used alone, or two or more colorants may be used in combination. Moreover, when using 2 or more types of coloring agents together, the coloring agent of the same color may be used together, and the coloring agent of the color of a several system | strain may be used together.
The content of the colorant can be selected from a wide range according to the required toner characteristics, but is more preferably 0.1% by weight or more and 20% by weight or less with respect to 100% by weight of the resin. More preferably, it is 0.1 wt% or more and 15 wt% or less. When the amount is less than 0.1% by weight, it is difficult to obtain a sufficient image density. When the amount exceeds 20% by weight, it is difficult to ensure dispersibility of the colorant in the formed image.

In addition to the above colorants, self-dispersing pigments that can be dispersed without adding a surfactant can also be used.
Examples of self-dispersing pigments include sulfonic acid groups, carboxyl groups and polymers on the pigment surface as disclosed in JP-T-10-510661, JP-T 2000-513396, and JP-T 2003-519709. And the like introduced directly on the pigment surface.

Moreover, what coated the pigment surface with a sulfonic acid group, a carboxyl group, a polymer, etc. by the phase inversion emulsification method etc. can also be used. The self-dispersing pigment has a hydrophilic functional group on the surface of the pigment, and the hydrophilic functional group is preferably an ionic group and / or an ionizable group.
Examples of the hydrophilic functional group include a group having a carboxylic acid group or a carboxylate; a group having a sulfonic acid group or a sulfonate; a group having a sulfophenyl group or a benzenesulfonate; a p-sulfophenyl group or p A group having a benzenesulfonate; a group having a carboxyphenyl group or a benzenecarboxylate; a group having a sulfoamide group or an amidosulfate; a group having a quaternary ammonium salt, or a derivative thereof, or a mixture thereof be able to.

  Self-dispersing pigments can be easily dispersed uniformly in water, and pigment agglomerates are unlikely to occur in the resulting toner, and an image with excellent color reproducibility can be obtained.

<Polyester resin (a)>
The core particle (A) according to the present invention is characterized by containing, as the polyester resin (a), a polymer of phthalic acids and glycols including at least phthalic acid and ester derivatives thereof, for example.
More specifically, as the polyester resin (a) contained in the core particle (A) according to the present invention, a known polyester resin that can be used as a binder resin for a toner can be used, but dispersibility in an aqueous medium having a sulfonate salt A polyester resin having an increased viscosity is preferred because of its excellent dispersibility in water.

  An aqueous dispersion of a polyester resin having a sulfonate salt is prepared by, for example, mixing a polyester resin having a sulfonate salt in a side chain and a water-soluble organic solvent in advance at a temperature in the range of 50 ° C. to 200 ° C., respectively. There is a method of manufacturing by adding.

  As another method, there is a method in which a mixture of a polyester resin having a sulfonate in the side chain and a water-soluble organic solvent is added to water and further stirred at a temperature in the range of 40 ° C to 120 ° C.

  As the water-soluble organic solvent, butanol, isopropanol, ethanol, butyl cellosolve, ethyl cellosolve, dioxane, tetrahydrofuran, acetone, methyl ethyl ketone, etc. can be used, but the water-soluble organic solvent makes an aqueous dispersion in which the core particles (A) are dispersed. Therefore, they are used as appropriate, not essential.

The average particle size of the aqueous fine dispersion dispersed in the aqueous dispersion is preferably in the range of 0.05 μm to 0.3.
When the average particle size is 0.3 μm or more, it is difficult to uniformly disperse the colorant in the core particles (A), and the color reproducibility of the toner is deteriorated. Further, if the resin is 0.05 μm or less, the hydrophilicity is too high, so that sufficient moisture resistance cannot be obtained for the obtained toner.
In particular, when preparing an aqueous fine dispersion using a water-soluble organic solvent, it takes time to remove the water-soluble organic solvent when the particle size of the aqueous fine dispersion is large. Is preferably 0.05 μm to 0.3 μm.

  Polyester resin (a) having a sulfonate in its side chain is a monomer of a polyvalent carboxylic acid, its ester derivative or a polyhydric alcohol having a sulfonate in its side chain together with a polyvalent carboxylic acid, its ester derivative and a polyhydric alcohol Obtained by polycondensation.

  Examples of the polyvalent carboxylic acid include terephthalic acid, isophthalic acid, orthophthalic acid, sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfophthalic acid, 5- (4-sulfophenoxy) isophthalic acid, sulfoterephthalic acid or esters thereof. Phthalic acids, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, anthracene dipropionic acid, anthracene dicarboxylic acid, diphenic acid, 4-sulfonaphthalene-2,7 dicarboxylic acid or their esters, metal salts or ammonium Aromatic dicarboxylic acids such as salts; aliphatic dicarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid and dodecanedicarboxylic acid or esters thereof; fumaric acid, maleic acid, itaconic acid, mesaconic acid and citraconic acid or es Aliphatic unsaturated polycarboxylic acids such as thiols; aromatic unsaturated polycarboxylic acids such as phenylene diacrylic acid or esters thereof; alicyclic dicarboxylic acids such as hexahydrophthalic acid and tetrahydrophthalic acid or esters thereof; Examples include trivalent or higher polyvalent carboxylic acids such as trimellitic acid, trimesic acid and pyromellitic acid or esters thereof.

Moreover, what contains monocarboxylic acids in polyhydric carboxylic acids as an acid component may be sufficient.
As monocarboxylic acids, aromatic monocarboxylic acids are preferable.
Examples of aromatic monocarboxylic acids include benzoic acid, chlorobenzoic acid, bromobenzoic acid, parahydroxybenzoic acid, naphthalenecarboxylic acid, anthracenecarboxylic acid, 4-methylbenzoic acid, 3-methylbenzoic acid, salicylic acid, thiosalicylic acid, Phenylacetic acid or lower alkyl esters thereof, sulfoammonium monoammonium salt, sulfobenzoic acid monosodium salt, cyclohexylaminocarbonylbenzoic acid, n-dodecylaminocarbonylbenzoic acid, tertiarybutylbenzoic acid and tertiarybutylnaphthalenecarboxylic acid or The ester etc. can be mentioned.

Examples of the polyhydric alcohols include aliphatic polyhydric alcohols, alicyclic polyhydric alcohols, and aromatic polyhydric alcohols.
Examples of aliphatic polyhydric alcohols include ethylene glycol, propylene glycol, 1,3-propanediol, 2,3-butanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol. , Glycols containing aliphatic diols such as neopentyl glycol, diethylene glycol, dipropylene glycol, 2,2,4-trimethyl-1,3-pentanediol, polyethylene glycol, polypropylene glycol and polytetramethylene glycol And triols such as trimethylol ethane, trimethylol propane, glycerin and pentaelsitol, or tetraols.

Examples of the alicyclic polyhydric alcohols include 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, spiroglycol, hydrogenated bisphenol A, ethylene oxide adduct and propylene oxide adduct of hydrogenated bisphenol A, tri Examples thereof include cyclodecane diol and tricyclodecane dimethanol.
Examples of aromatic polyhydric alcohols include para-xylene glycol, meta-xylene glycol, ortho-xylene glycol, 1,4-phenylene glycol, ethylene oxide adduct of 1,4-phenylene glycol, bisphenol A, ethylene of bisphenol A Examples thereof include an oxide adduct (bisphenol A ethoxylate) and a propylene oxide adduct (bisphenol A propoxylate).

  Moreover, the alcohol component may contain monoalcohols in polyhydric alcohols. Examples of monoalcohols include aliphatic alcohols, aromatic alcohols, and alicyclic alcohols.

  As the monomer having a sulfonate salt as a hydrophilic monomer in the side chain, polyvalent carboxylic acids or monocarboxylic acids having an alkali metal sulfonate, ammonium sulfonate, or the like in the side chain can be used, for example, 5-sodium sulfo Examples include xyisophthalic acid. The hydrophilic monomer may be polymerized simultaneously with other monomers from the start of polymerization, or may be added during the polymerization.

  Specific examples of the polyester resin (a) used in the present invention include polymers of phthalates and glycols. More specifically, mention may be made of polymers of dimethyl terephthalate, dimethyl isophthalate, 5-sodium sulfodimethyl isophthalate, ethylene glycol and propylene glycol.

  The ionic group of the toner has a function of imparting water dispersibility to the polyester resin, but when the counter cation is a polyvalent ion, the water dispersibility cannot be sufficiently exhibited. Therefore, the counter cation of these ionic group-containing monomers in polymerizing the polyester is preferably a monovalent cation. Considering the moisture resistance of the finally obtained toner and the water dispersibility in the production process, the ion equivalent of the polyester is preferably 10 meq / kg or more and 1000 meq / kg or less. More preferably, it is in the range of 20 meq / kg or more and 100 meq / kg or less.

<Core particle (A)>
The core particle (A) of the present invention contains at least a colorant and a polyester resin (a) and is aggregated from an aqueous dispersion such as a polyester resin or a colorant, or constitutes a colorant or a polyester resin (a). It can be produced by suspension polymerization of an aqueous suspension containing monomers.
Moreover, petroleum wax, a charge control agent, etc. can be added to the core particles (A) as required.

Regarding the number average particle diameter of the core particles (A), it is difficult to uniformly charge the toner when the particle diameter of the toner is 2 μm or less. Therefore, image defects are likely to occur when an image is formed using the toner. . On the other hand, when the toner particle diameter is 10 μm or more, when an image is formed using the toner, the toner particle diameter is too large and satisfactory image quality is hardly obtained.
On the other hand, when the core particles (A) have a number average particle diameter of 2 μm to 10 μm, image defects are hardly caused and no deterioration in image quality is observed. Therefore, a core having a number average particle diameter of 2 μm to 10 μm Particles are preferred. In particular, toner particles having a number average particle diameter of 2 μm to 5 μm are preferable in order to achieve the purpose of improving the image quality.

  The method for producing the aqueous dispersion of the core particles (A) is not particularly limited, but in consideration of the particle size controllability and production efficiency for the small particle size toner, the degree of freedom in selecting the resin material, An aqueous dispersion of colored resin particles obtained by agglomerating from an aqueous dispersion comprising a polyester tree (a) is suitable.

  As a method of obtaining an aqueous dispersion of colored resin particles obtained by agglomerating from an aqueous dispersion containing the polyester resin, for example, after polyester resin is melted and emulsified into fine resin particles of 0.5 μm or less with a stirrer such as a homogenizer A colorant aqueous dispersion, a charge control agent aqueous dispersion, a petroleum wax aqueous dispersion, and the like are added and mixed, and then a flocculant is added to agglomerate the core particles (A).

  The polyester resin (a) contained in the core particle (A) may be any resin that can be dispersed using a stirrer in an aqueous medium heated without using a dispersant such as a surfactant. Resins having hydrophilic groups in the side chain such as sulfonates, carboxylic acids and carboxylates can be used.

  The dispersed particle diameter of the polyester resin depends on the content of the hydrophilic group in the polyester resin, and the dispersed particle diameter decreases as the content increases. Furthermore, the dispersed particle size of the polyester resin also depends on the molecular weight of the resin, and the dispersed particle size with a small molecular weight becomes small. Therefore, the dispersed particle diameter of the polyester resin in the aqueous medium can be controlled by changing the hydrophilic group content and the molecular weight of the resin.

  Among polyester resins, when a resin using a polyester resin having a sulfonate in the side chain is aggregated using a divalent or higher flocculating agent such as magnesium sulfate, an ionic cross-linked structure is formed via sulfate ions and magnesium ions. Therefore, the same effect as that of the high molecular weight resin can be obtained, and the hot offset resistance can be improved.

  In the melt emulsification method, if it is attempted to disperse using a resin having a large molecular weight from the beginning, there is a demerit that the time required for the dispersion becomes long and the productivity is lowered. Since a small resin can be used, both the productivity in the dispersion process and the improvement of the hot offset resistance of the obtained toner can be achieved. As divalent or higher valent metal ions, for example, magnesium sulfate, magnesium sulfate, aluminum sulfate, and the like can be used.

<Petroleum wax>
Petroleum wax may be added to the core particles (A) as needed for the purpose of improving low-temperature fixability. As a method of adding the petroleum wax to the inside of the toner, for example, there is a method of aggregating an aqueous petroleum wax dispersion together with an aqueous resin dispersion.

  As the petroleum wax aqueous dispersion, a dispersion obtained by stirring and dispersing petroleum wax together with a dispersant and a surfactant with a stirring device can be used. An aqueous dispersion in which petroleum wax is dispersed so that the number average particle size is 0.3 μm or less can be used. However, in order to obtain a toner having more excellent transparency and color reproducibility, the dispersion is 0.3 μm or less. It is preferable to use what was done.

As the petroleum-based wax, known ones can be used, and examples thereof include paraffin wax and microcrystalline wax.
Further, carnauba wax, rice wax, candelilla wax, etc. having a melting point of less than 100 ° C. may be used in place of petroleum wax.

<Charge control agent>
In the toner of the present invention, a charge control agent can also be used. That is, the core particle (A) according to the present invention contains at least a colorant, but it goes without saying that a charge control agent may be contained in the core particle (A) as well as this colorant. Moreover, the petroleum-based wax described above may be included at the same time.
Therefore, as a method for adding the charge control agent to the inside of the toner, for example, a method in which the charge control agent is dispersed in the resin in advance using a melt kneader or a petroleum wax aqueous dispersion is aggregated together with the resin aqueous dispersion. There is a way to make it.

  As the charge control agent aqueous dispersion, a dispersion in which the charge control agent is stirred and dispersed together with a dispersant and a surfactant by a stirring device can be used. An aqueous dispersion in which the charge control agent is dispersed so that the number average particle diameter is 0.3 μm or less can be used. However, in order to obtain a toner having more excellent transparency and color reproducibility, the dispersion is 0.3 μm or less. It is preferable to use what was done.

  Examples of the charge control agent for controlling positive charge include organic compounds having a basic nitrogen atom, such as basic dyes, quaternary ammonium salts, aminopyrines, pyrimidine compounds, polynuclear polyamino compounds, aminosilanes, and nigrosine bases.

  Examples of the charge control agent for controlling the negative charge include oil-soluble dyes such as oil black and spiron black, metal-containing azo dyes, metal salts of naphthenic acid, metal salts of alkyl salicylic acid, fatty acid soaps, and resin acid soaps.

  The amount of the charge control agent added is in the range of 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the binder resin. By adding the charge control agent to the toner of the present invention, the charging characteristics of the toner can be controlled.

  In the toner of the present invention, when adjusting each of the aqueous colorant dispersion, the petroleum wax aqueous dispersion, the charge control agent aqueous dispersion, and the resin aqueous dispersion, when controlling the dispersed particle diameter, A surfactant may be used within a range that does not affect the above.

  The surfactant that can be used may be any of a nonionic surfactant, an anionic surfactant, a cationic surfactant, and an amphoteric surfactant. However, in the case of aggregating polyester resin particles having a sulfonate salt in the side chain, when using a divalent or higher flocculating agent such as magnesium sulfate or aluminum sulfate, a colorant or It is preferable that the surfactant used in the petroleum-based wax is substantially free of a cationic surfactant.

  Examples of the nonionic surfactant include polyoxyalkylene alkyl ethers such as polyoxyethylene lauryl ether and polyoxyethylene stearyl ether; polyoxyalkylene alkyl phenol ethers such as polyoxyethylene octylphenol ether and polyoxyethylene nonylphenol ether. Sorbitan fatty acid esters such as sorbitan monolaurate, sorbitan monostearate, sorbitan trioleate; polyoxyalkylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monolaurate; polyoxyethylene monolaurate, polyoxyethylene monostea Polyoxyalkylene fatty acid esters such as oleates; oleic acid monoglycerides, stearic acid monoglycerides, etc. Glycerin fatty acid esters; can be exemplified polyoxyethylene polypropylene block copolymer and the like.

  Examples of the anionic surfactant include fatty acid salts such as sodium stearate, sodium oleate, and sodium laurate; alkylaryl sulfonates such as sodium dodecylbenzenesulfonate; alkyl sulfate esters such as sodium lauryl sulfate; Alkylsulfosuccinic acid ester salts such as sodium octylsulfosuccinate, sodium dioctylsulfosuccinate, sodium polyoxyethylene lauryl sulfosuccinate and derivatives thereof; polyoxyalkylene alkyl ether sulfates such as sodium polyoxyethylene lauryl ether sulfate; polyoxyethylene And polyoxyalkylene alkylaryl ether sulfate esters such as nonylphenol ether sulfate

  Examples of the cationic surfactant include alkylamine salts such as laurylamine acetate; quaternary ammonium salts such as lauryltrimethylammonium chloride and alkylbenzyldimethylammonium chloride; polyoxyethylalkylamine and the like. Examples of the surfactant include alkyl betaines such as lauryl betaine. Moreover, what substituted a part of hydrogen of the alkyl group by the fluorine in the said surfactant can also be used.

<Shell layer>
The shell layer includes an α-olefin polymer having a melting point of 55 ° C. or higher and 70 ° C. or lower obtained by polymerizing an α-olefin having 16 or more carbon atoms, and a polyester resin (B ) And is formed on the surface of the core particle (A).
The thickness of the shell layer is preferably 0.3 μm to 1 μm because a sufficient improvement in storage stability cannot be obtained when the thickness is 0.3 μm or less, and the low-temperature fixability is lowered when the thickness is 1 μm or more.

<Polyester resin (B)>
As the polyester resin (B), a known polyester resin that can be used as a binder resin for a toner can be used. However, a polyester resin obtained from a monomer component similar to the polyester resin used in the core particles (A) can be used. preferable.
That is, the polyester resin (B) in the present invention is characterized in that it contains at least a polymer of phthalic acids, glycols and bisphenol A alkoxylates containing, for example, phthalic acid and ester derivatives thereof.

  The glass transition point of the polyester resin (B) is usually 45 ° C. to 75 ° C., preferably 50 ° C. to 65 ° C., but from the glass transition point of the polyester resin contained in the core particles (A). A material having a temperature higher by 2 ° C. to 10 ° C. is preferable because the aggregation resistance (storability in a high temperature environment) is improved.

As the water-soluble organic solvent, the solvents described in the polyester resin (a) can be used in the same manner.
Moreover, as monomers used for the production of the polyester resin (B), the monomers described in the polyester resin (a) can be used.

  Specific examples of the polyester resin (B) used in the present invention include polymers of phthalic acids, glycols and bisphenol A alkoxylates as polyesters. More particularly, mention may be made of polymers of phthalic acid or phthalic acid esters, ethylene glycol or propylene glycol and bisphenol A methoxylate, bisphenol A ethoxylate or bisphenol A propoxylate. More specifically, mention may be made of polymers of dimethyl terephthalate, dimethyl isophthalate, ethylene glycol and bisphenol A ethoxylate.

  The average particle size of the aqueous fine dispersion dispersed in the aqueous dispersion is preferably in the range of 0.05 μm to 0.3. If it is 0.3 μm or more, it is difficult to uniformly disperse the colorant in the core particles (A), and the color reproducibility of the toner is lowered. Further, if the resin is 0.05 μm or less, the hydrophilicity is too high, so that sufficient moisture resistance cannot be obtained for the obtained toner. In particular, when preparing an aqueous fine dispersion using a water-soluble organic solvent, it takes time to remove the water-soluble organic solvent when the particle size of the aqueous fine dispersion is large. Is preferably 0.05 μm to 0.3 μm.

  The particle size of the polyester resin dispersed in the aqueous medium can be controlled by changing the molecular weight of the resin and the carboxylate content in the resin. If the molecular weight of the resin is reduced, emulsification is facilitated and the dispersed particle size is reduced. If the amount of carboxylate in the resin is increased, emulsification is facilitated and the dispersed particle size is reduced, but if the acid value is too high, the hygroscopicity is increased, and as a result, the resulting toner has moisture resistance, i.e., The acid value is preferably 5 to 30 mgKOH / g in order to cause a decrease in charge amount and a decrease in transfer efficiency in a high humidity environment.

  As a method of increasing the carboxylic acid group contained in the polyester resin (B), there is a method of using a trivalent or higher carboxylic acid monomer. If a trivalent or higher carboxylic acid monomer is added at the initial stage of the polymerization reaction, a cross-linked structure is imparted to the polyester resin and subsequent emulsification and dispersion becomes difficult. As a result, it is possible to minimize the increase in molecular weight due to the crosslinking reaction and increase the acid value of the resin.

  When trivalent or higher polyvalent carboxylic acids such as trimellitic acid, trimesic acid and pyromellitic acid are used together with the above polyvalent carboxylic acids, unreacted carboxylic acid groups are more likely to be contained. If it is introduced at the end of the reaction, it becomes easy to introduce a carboxylic acid group without causing a crosslinking reaction.

  In the process of forming the polyester resin (B), in addition to the polyester resin having a carboxylate in the side chain, a resin having no self-dispersibility can be simultaneously added. In that case, if the content of the polyester resin having a carboxylate in the side chain in the polyester resin (B) is less than 50% by weight, it becomes difficult to make a uniform aqueous dispersion. The resin content is preferably 50% by weight or more.

<Higher α-olefin polymer (C)>
The higher α-olefin polymer (C) is a side chain crystalline resin having a melting point of 55 ° C. or higher and 70 ° C. or lower obtained by polymerizing an α-olefin having 16 or more, preferably 16 to 28 carbon atoms, at a high temperature. In addition to the property of high viscosity (can maintain the release effect at high temperature), the hardness is high (coagulation) even though the melting point is low (does not inhibit the low temperature fixability) due to the crystallinity of the side chain. It is difficult). As a result, the capsule toner coated on the surface becomes a toner excellent not only in hot offset resistance but also in low-temperature fixability and aggregation resistance (storage stability).

  When the blending ratio of the α-olefin polymer to the polyester resin is low, the above effect is hardly exhibited. Conversely, when the blending ratio of the α-olefin polymer to the polyester resin is high, the α-olefin polymer to the polyester resin is easily separated. The blend ratio of the polymer is preferably 100: 5 to 100: 20.

  The α-olefin polymer can be produced, for example, by a method described in JP-A-2008-102238. That is, 5 liters obtained by heating and drying a fraction obtained by distilling α-olefin (produced by Idemitsu Kosan Co., Ltd., trade name: “Linearene 2024”) under reduced pressure (2 to 14 mmHg) at a distillation temperature of 140 to 230 ° C. And dehydrated with dry nitrogen and activated alumina for 8 hours. A dehydrated α-olefin fraction of 5 liters was placed in a heat-dried 10 liter autoclave and heated to a polymerization temperature of 90 ° C., then 12 mmol of triisobutylaluminum, (1,2′-dimethylsilylene) (2, 25 μmol of 1′-dimethylsilylene) bis (3-trimethylsilylmethylindenyl) zirconium dichloride (toluene slurry [20 μmol / mL, 1.25 mL]), 100 μmol of dimethylanilinium tetrakispentafluorophenylborate (toluene slurry [20 μmol / mL, 5 mL]), hydrogen 0.1 MPa is introduced, and polymerization is performed for 4 hours.

<Flocculant>
As the aggregating agent used when the surface of the core particle (A) is coated with the polyester resin (B) and the higher α-olefin polymer (C), known substances such as electrolytes and organic substances having ions can be used. A polyvalent ionic compound that can take an ionic cross-linked structure between the polymer molecule and the polymer molecule is preferable in that it has an effect of increasing the molecular weight of the resin. As the polyvalent ion compound, polyvalent metal salts such as magnesium sulfate and aluminum sulfate are preferable because they are easily dissolved in water and easily washed with pure water.

<Washing water>
As pre-purified water used for washing, pure water having a conductivity of 20 μS / cm or less is preferable. Such pure water can be obtained by a known method, and examples thereof include pure water obtained by an activated carbon method, an ion exchange method, a distillation method and a reverse osmosis method. Further, a plurality of methods may be combined and commercially available pure water may be used.
Moreover, the temperature of the pure water at the time of washing | cleaning has preferable 10 to 80 degreeC.

<External additive>
As described above, a known external additive can be added to the toner of the present invention for the purpose of improving fluidity and chargeability.
Commonly used external additives include silica, titanium oxide, aluminum oxide having an average particle size of 0.007 μm to 0.02 μm, and surface treatment with silane coupling agent, titanium coupling agent, and silicone oil. The applied inorganic fine particles are used.

In addition, since the surface of the toner obtained in the present invention is relatively smooth, the second external additive having an average particle size of 0.03 μm to 0.2 μm for the purpose of improving transferability, cleaning properties and aggregation prevention. It is desirable to use together.
Examples of the second external additive include silica, titanium oxide, aluminum oxide, and inorganic fine particles which are surface-treated with a silane coupling agent, a titanium coupling agent, and silicone oil. Examples thereof include zinc, calcium stearate, lead stearate, zinc oxide powder, vinylidene fluoride fine particles, and fluorine resin fine particles such as polytetrafluoroethylene fine particles.

  The amount of the external additive to be added is preferably in the range of 0.3 to 3 parts by weight with respect to 100 parts by weight of the toner body. If it is 0.3 parts by weight or less, the effect of improving the fluidity cannot be obtained, and if it is 3 parts by weight or more, the fixability is lowered.

  Further, abrasive fine particles can be added to the toner. Specific examples include fine abrasive particles such as strontium titanate, cerium oxide, silicon carbide, and magnetite. These fine particles may be treated with a coupling agent such as a silane coupling agent or a titanium coupling agent, silicone oil, or other organic compounds. Abrasive fine particles having a particle size in the range of 0.04 to 2 μm can be used. If the amount of the abrasive fine particles added is too large, the surface of the electrostatic latent image carrier and the developer carrier is rapidly worn, so that the amount added is preferably 2 parts by weight or less with respect to 100 parts by weight of the toner particles.

  As described above, a capsule toner that achieves the object of the present invention can be obtained. The particle diameter of the toner of the present invention is not particularly limited, but a number average particle diameter of 3 to 11 μm is preferable in view of improvement in image quality. In consideration of toner scattering in the developing device, image density stability, and excellent dot reproducibility, the number average particle diameter is more preferably 4 to 6 μm.

<Developer>
The toner obtained in the present invention can be used as a one-component developer or a two-component developer. As the two-component developer, for example, a developer in which the toner of the present invention and a carrier are mixed can be used.

  As the carrier, known ones can be used, and examples thereof include a carrier in which ferrite particles and iron powder particles are surface-coated with a coating material, and a carrier in which magnetic powder is dispersed in a binder resin. Examples of the coating material include polytetrafluoroethylene, monochlorotrifluoroethylene polymer, polyvinylidene fluoride, silicone resin, polyester resin, metal compound of ditertiary butylsalicylic acid, styrene resin, acrylic resin, polyacid, polyvinyl Lar, nigrosine, amino acrylate resin, basic dye, basic dye lake, silica fine powder, alumina fine powder, carbon black and the like. Moreover, a coating substance may be used individually by 1 type, and may be used in combination of 2 or more type. Although there is no restriction | limiting in particular as a volume average particle diameter of a carrier, A 20 micrometers-50 micrometers carrier is preferable when the improvement of image quality and stability of image density are considered.

[Method for producing capsule toner]
Next, a method for producing the capsule toner of the present invention will be described.
FIG. 1 is a diagram showing an example of a method for producing a capsule toner of the present invention, in which S1: an aqueous dispersion production process of a polyester resin (a), S2: an aqueous dispersion production process of a colorant, and S3: a petroleum wax. S4: aqueous dispersion production process of S4: core particle (A), S5: aqueous dispersion production process of polyester resin particles (B), S6: aqueous of higher α-olefin polymer particles (C) The dispersion liquid production step, S7: coated particle forming step, S8: smoothing step, S9: filtration washing step, S10: drying step, S11: external addition step.

<S1: Polyester resin (a) aqueous dispersion production process>
First, S1: Polyester resin (a) aqueous dispersion manufacturing process of FIG. 1 prepares the aqueous dispersion by dispersing the polyester resin used as the binder resin of the core particles (A) in water with a stirrer. It is a process.

As the stirrer in the toner production method of the present invention, known emulsifiers and dispersers can be used. Specifically, Ultra Turrax (trade name: manufactured by IKA Japan Co., Ltd.), Polytron homogenizer (trade name: manufactured by Kinematica Co., Ltd.) and TK Auto Homo Mixer (trade name: manufactured by Tokushu Kika Kogyo Co., Ltd.) Batch type emulsifier, Ebara Milder (trade name: manufactured by Ebara Manufacturing Co., Ltd.), TK Pipeline Homomixer (trade name: manufactured by Tokushu Kika Kogyo Co., Ltd.), TK Homomic Line Flow (trade name: Special Machine) Chemical Industry Co., Ltd.), Fillmix (trade name: Special Machine Chemical Industry Co., Ltd.), colloid mill (trade name: Shinko Pantech Co., Ltd.), Thrasher (trade name: Mitsui Miike Chemical Industries, Ltd.) ), Trigonal wet milling machine (trade name: manufactured by Mitsui Miike Chemical Co., Ltd.), Cavitron (trade name: manufactured by Eurotech Co., Ltd.) and Fine Flow Mill (trade name: Taiheiyo Kiko Co., Ltd.) ) Continuous emulsification machine such as, Claire mix: manufactured (trade name M Technique Co., Ltd.) and fill mix: manufactured (trade name Kika Kogyo Co., Ltd.), and the like.
The emulsifier and the disperser preferably have a heat retaining means.

<S2: Colorant aqueous dispersion production process>
S2: The colorant aqueous dispersion manufacturing step is carried out by dispersing a colorant used as a colorant internally added in the core particles (A) in water with a stirrer, so that the number average particle diameter is 0.05 μm to 0.00 μm. This is a step of preparing a 3 μm aqueous dispersion.

<S3: Process for producing an aqueous dispersion of petroleum wax (also referred to as release agent or mold release agent)>
S3: The process for producing an aqueous dispersion of petroleum-based wax is carried out by dispersing a petroleum-based wax used as a release agent internally added in the core particles (A) in water with a stirrer, so that the number average particle diameter is 0.05 μm. This is a step of preparing an aqueous dispersion of ˜0.5 μm.

<S4: Process for producing aqueous dispersion of core particles (A)>
S4: A core particle (A) aqueous dispersion manufacturing process includes S1: polyester resin (a) aqueous dispersion manufacturing process, S2: colorant aqueous dispersion manufacturing process, and S3: petroleum wax aqueous dispersion manufacturing process. In the step of preparing an aqueous dispersion of core particles (A) having a number average particle diameter of 2 μm to 10 μm by mixing the aqueous dispersion adjusted in each step of the step and then aggregating by heating or adding a flocculant. is there.

<S5: Aqueous dispersion manufacturing process of polyester resin particles (B)>
S5: The aqueous dispersion manufacturing process of the polyester resin particles (B) is performed by dispersing the polyester resin particles (B) used as the resin for forming the shell layer on the surface of the core particles (A) in water with a stirrer, This is a step of preparing an aqueous dispersion having a particle size of 0.05 μm to 0.5 μm.

  If the number average particle diameter of the polyester resin (B) is less than 0.05 μm or exceeds 0.5 μm, the shell layer becomes too thick or it becomes difficult to obtain a uniform shell layer. The number average particle diameter is preferably 0.05 μm to 0.5 μm.

<S6: Process for producing aqueous dispersion of higher α-olefin polymer particles (C) (wax)>
S6: The step of producing an aqueous dispersion of the higher α-olefin polymer particles (C) is performed by using a stirrer to convert the higher α-olefin polymer particles (C) used as a resin for forming the shell layer on the surface of the core particles (A). In an aqueous dispersion having a number average particle size of 0.05 μm to 0.5 μm.

<S7: coated particle forming step>
S7: The coated particle forming step mixes the aqueous dispersion of the core particles (A), the aqueous dispersion of the polyester particles (B), and the aqueous dispersion of the higher α-olefin polymer particles (C). The polyester resin particles (B) and the higher α-olefin polymer are formed on the surface of the core particles (A) by heating the obtained mixture or adding a flocculant to the obtained mixture. This is a step of forming coated particles in water by coating the particles (C).

<S8: Smoothing step>
S8: In the smoothing step, the coated particles are heated while maintaining a dispersed state in water to smooth the surface of the coated particles, and the aqueous dispersion of the core particles (A) and the polyester particles (B) And a step of firmly fusing the higher α-olefin polymer particles (C). By heating the aqueous medium containing the coated particles at a temperature equal to or higher than the glass transition point (Tg) of the polyester resin (B), a strong shell layer can be formed, whereby the shell layer is peeled off in the developing device. A hard capsule toner can be obtained.

  At this time, the higher α-olefin polymer particles (C) melt on heating and may bleed on the toner surface, so that the melting point of the α-olefin polymer is higher than the glass transition point of the polyester particles (B). It is preferable to heat to a temperature not lower than the glass transition point of the polyester particles (B) and not higher than the melting point of the α-olefin polymer.

  Since the core particles (A) and the highly adhesive polyester particles (B) are held in the shell layer, the higher α-olefin polymer particles (C) are less likely to be detached from the shell layer.

  In order to improve the low-temperature fixability (preventing cold offset), it is preferable to add a petroleum wax only inside the core particles (A). In this case, the melting point of the petroleum wax is such that the polyester particles ( It is preferable to select a material that is higher than the glass transition point of B) and then heat to a temperature not lower than the glass transition point of the polyester particles (B) and not higher than the melting point of the petroleum wax.

<S9: Filtration washing process>
S9: The filtration washing step is a step of washing the capsule toner particles with pure water after removing the filtrate by filtering the toner main body particles. Cleaning of toner using pure water is performed to remove unnecessary components other than toner components such as impurities that affect the chargeability of the toner, but the cleaning method is performed in a batch manner. Alternatively, it may be performed continuously. Further, the toner is preferably washed until the conductivity of the supernatant is 50 μS / cm or less.

  In addition, in order to improve the dispersibility of the polyester resin particles (B) in water, dilute hydrochloric acid is added prior to the filtration washing step when a polyester resin having a carboxylate introduced into the side chain of the polyester resin is used. Therefore, it is better to apply a hydrophobization treatment. As a result, the carboxylate on the toner surface is converted to carboxylic acid, so that a capsule toner having excellent moisture resistance can be produced.

  As a specific treatment method, for example, an aqueous dispersion of aggregated particles is heated to a temperature of Tg or higher to form stronger aggregated particles, and then the pH is adjusted to 2-3 in a suspension in which the aggregated particles are dispersed. A method of adding an adjusted aqueous hydrochloric acid solution is preferred.

<S10: Drying process>
S10: The drying step is a step of drying the toner particles under a reduced pressure condition. Thereby, the capsule toner in the present invention can be obtained.

<S11: External addition process>
S11: The external addition step is a step of manufacturing the externally added capsule toner by mixing the capsule toner manufactured through the S10: drying step and the external additive. This improves the fluidity of the capsule toner. For mixing the capsule toner and the external additive, a wind stirrer such as a Henschel mixer can be used.

  S10: Since the toner particles obtained in the drying step form a gentle aggregate, it is desirable to disintegrate the toner particles in advance using a Henschel mixer or the like. In the present invention, the externally added capsule toner obtained in S11: external addition process may be simply referred to as capsule toner or toner.

  Examples and comparative examples of the capsule toner of the present invention will be described below.

Example 1
Hereinafter, although the toner and the manufacturing method thereof according to the present invention will be described in detail by way of examples, the present invention is not limited to the following examples.
In the following examples, the melting point (Tm) and glass transition point of the obtained polymer were determined by DSC (Differential Scanning Calorimeter) measurement, that is, a differential scanning calorimeter (manufactured by Perkin Elmer, DSC-7). The sample was held at a nitrogen atmosphere at 0 ° C. for 3 minutes and then heated at 10 ° C./min. The peak top of the melting endotherm curve obtained was the melting point (Tm), and the melting endotherm curve was refracted. The temperature was taken as the glass transition point.

The molecular weight of the obtained polymer was determined by GPC (gel permeation chromatography) measurement, the sodium sulfonate group equivalent was determined by quantitative determination of sulfur, the acid value was determined by acid-base titration, and the reduced viscosity was 0.01 g of polyester resin. Was dissolved in 250 cc of a mixed solvent of phenol / tetrachloroethane (weight ratio 6: 4) and measured at a measurement temperature of 30 ° C. using an Ostwald viscometer.
Further, the penetration at 25 ° C. was performed according to the penetration test method defined in JIS K2235-1991. As an apparatus for measuring the penetration, an automatic penetration meter (trade name: RPM-101, manufactured by Koiso Co., Ltd.) was used.
The obtained particle diameter was measured using Coulter Multisizer II (manufactured by Coulter).

<Manufacture of polyester resin (a) for core particles (A)>
In an autoclave equipped with a thermometer and a stirrer,
・ 108 parts by weight of dimethyl terephthalate ・ 80 parts by weight of dimethyl isophthalate ・ 6 parts by weight of 5-sodium sulfodimethylisophthalate ・ 100 parts by weight of ethylene glycol ・ 53 parts by weight of propylene glycol and 0.1 part by weight of tetrabutoxy titanate The reaction is carried out by stirring for 120 minutes while heating at 150 ° C. or higher and 230 ° C. or lower. Then, it heated to 250 degreeC, pressure-reduced the pressure of the reaction system to 1 mmHg or more and 10 mmHg or less, and it stirred for about 1 hour, and also was made to react, and polyester resin (a) (3 kg) was obtained.

  The obtained polyester resin (a) has a number average molecular weight: 2500, a weight average molecular weight: 6200, a glass transition point: 55 ° C., a sodium sulfonate group equivalent: 89 meq / kg, an acid value: 2.2 mgKOH / g, a reduced viscosity. : 0.336.

<Production of aqueous dispersion of polyester resin (a)>
100 parts by weight of the polyester resin (a) obtained by the above synthesis method and 75 parts by weight of butyl cellosolve are added to a four-necked 10-liter separable flask equipped with a thermometer, a condenser and a stirring blade, and stirred at 70 ° C. And dissolved. Next, after adding 500 weight part of 70 degreeC ionic water and making it disperse | distribute to water, it distilled and distilled until the fraction temperature reached 100 degreeC with the flask for distillation. Thereafter, pure water (ion exchange water) was added so that the solid content concentration was 30% to obtain an aqueous polyester resin (a) dispersion (10 kg). The number average particle diameter of the finely dispersed particles present in the obtained polyester aqueous dispersion a was 0.1 μm.

<Production of aqueous dispersion of colorant>
Homogenizer (manufactured by Polytron, PT3000)
・ 50 parts by weight of cyan pigment (manufactured by BASF: Eupolene Blue 69-1501) ・ 5 parts by weight of anionic surfactant (Neogen R, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) ・ Add 223 parts by weight of deionized water and stir for 20 minutes Then, an aqueous colorant dispersion (5 kg) having a particle size of 0.2 μm was obtained by treating with an ultrasonic homogenizer.

<Production of aqueous dispersion of petroleum wax>
Homogenizer (manufactured by Polytron, PT3000)
・ After adding paraffin wax (Nippon Seiwa Co., Ltd., HNP10, melting point 75 ° C.) 50 parts by weight ・ Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen R) 5 parts by weight ・ After adding 161 parts by weight of ion-exchanged water The mixture was stirred for 20 minutes while being heated to 95 ° C. to obtain a petroleum wax aqueous dispersion (5 kg) having a number average particle size of 0.3 μm.

<Production of aqueous dispersion of core particles (A)>
The above polyester resin (a) aqueous dispersion, colorant aqueous dispersion, and petroleum wax aqueous dispersion were added to a homogenizer (manufactured by Polytron, PT3000) with a solid concentration of 90% by weight, 5% by weight, and 5% by weight, respectively. Then, a 0.1 wt% aqueous magnesium sulfate solution was added dropwise with stirring at a rotational speed of 2000 rpm. Thereafter, the mixture was stirred for 1 hour to obtain an aqueous dispersion (20 kg) in which core particles (A) having a volume average particle diameter of 6 μm were dispersed.

<Manufacture of polyester resin (B)>
In an autoclave equipped with a thermometer and a stirrer,
-132 parts by weight of dimethyl terephthalate-60 parts by weight of dimethyl isophthalate-68 parts by weight of ethylene glycol-Bisphenol A ethoxylate
(Average molecular weight 350) 175 parts by weight and 0.1 part by weight of tetrabutoxy titanate were charged, heated at 150 to 220 ° C. for 180 minutes for transesterification, then heated to 240 ° C., and then the pressure of the system Was gradually reduced to 10 mmHg 30 minutes later, and the reaction was continued for 70 minutes. Thereafter, the inside of the autoclave was replaced with nitrogen gas to obtain atmospheric pressure. While maintaining the temperature at 200 ° C., 2 parts by weight of trimellitic anhydride was added, and the reaction was performed for 70 minutes to obtain a polyester resin (B) (3 kg). The obtained polyester resin had a glass transition point: 55 ° C., an acid value: 21.2 mgKOH / g, a number average molecular weight: 2800, and a weight average molecular weight: 6500.

<Production of polyester resin (B) aqueous dispersion>
100 parts by weight of polyester resin (B) obtained by the above synthesis method, 48 parts by weight of butanol, 12 parts by weight of methyl ethyl ketone and 20 parts by weight of isopropanol were added and dissolved at 70 ° C. Further, a 5% aqueous sodium hydroxide solution was added so that the acid value of the copolyester was equal, and the mixture was stirred at 65 ° C. for 30 minutes, and then 300 parts by weight of water at 65 ° C. was added to obtain an aqueous fine dispersion of the copolyester. (3 kg) was obtained. Further, the obtained aqueous dispersion was put into a distillation flask, distilled until the fraction temperature reached 100 ° C., cooled, and the solid content was adjusted with ion-exchanged water (deionized water) to finally remove the solvent. A polyester resin (B) aqueous dispersion (10 L) having a solid content concentration of 30% was obtained. The number average particle diameter of finely dispersed particles present in the obtained polyester resin (B) aqueous dispersion was 0.1 μm.

<Production of higher α-olefin polymer (C)>
Higher α-olefin (made by Idemitsu Kosan Co., Ltd., trade name: “Linearene 2024”) was distilled under reduced pressure (2 to 14 mmHg) at a distillation temperature of 140 to 230 ° C., and the composition was C22: 64.1. % And C24: 35.9% of C22 and 24 α-olefin fractions were obtained. The obtained α-olefin fraction was introduced into 5 liters of heat-dried Schlenk, and dehydrated with dry nitrogen and activated alumina for 8 hours.

  A dehydrated α-olefin fraction of 5 liters was placed in a heat-dried 10 liter autoclave and heated to a polymerization temperature of 90 ° C., then 12 mmol of triisobutylaluminum, (1,2′-dimethylsilylene) (2, 25 μmol of 1′-dimethylsilylene) bis (3-trimethylsilylmethylindenyl) zirconium dichloride (toluene slurry [20 μmol / mL, 1.25 mL]), 100 μmol of dimethylanilinium tetrakispentafluorophenylborate (toluene slurry [20 μmol / mL, 5 mL]) was added, hydrogen 0.1 MPa was introduced, and polymerization was carried out for 4 hours.

  After completion of the polymerization reaction, the reaction product was precipitated with acetone, and then the precipitate was heated and dried under reduced pressure to obtain 3.2 kg of an α-olefin copolymer (C). The resulting higher α-olefin polymer (C) had a DSC melting point of 60 ° C. and a penetration of 1 at 25 ° C.

<Production of aqueous dispersion of higher α-olefin polymer (C) (wax)>
Homogenizer (manufactured by Polytron, PT3000)
-Higher α-olefin polymer (C) 50 parts by weight-Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen R) 7.5 parts by weight-Ion-exchanged water 160 parts by weight The mixture was stirred for 20 minutes with heating to obtain an aqueous dispersion (12 kg) of a higher α-olefin polymer (C) having a number average particle size of 0.3 μm.

<Coated particle forming step>
The aqueous dispersion of the core particle (A) aqueous dispersion, the polyester resin (B) aqueous dispersion, and the higher α-olefin polymer (C) has a solid content concentration of 100 parts by weight, 7 parts by weight, and 0.7 parts by weight, respectively. After adjusting 30 L of the mixture, 0.1 wt% aqueous magnesium sulfate solution (100 ml) was added dropwise little by little, followed by stirring for 1 hour to form coated particles.

<Smoothing process>
The aqueous medium containing the coated particles was heated to 58 ° C. and stirred for 120 minutes to perform a smoothing treatment.

<Filter washing process>
After the supernatant of the aqueous medium was exchanged with pure water (ion exchange water) three times, an aqueous hydrochloric acid solution having a pH of 2 was added. Thereafter, the agglomerate was washed twice with pure water (ion exchange water) and filtered to take out a wet cake-like agglomerate of toner particles. In addition, the water (ion-exchange water) used for washing | cleaning is the pure water of the conductivity 0.5 microsiemens / s prepared from the tap water using the ultrapure water manufacturing apparatus (ADVANTEC company_made: Ultra Pure Water System CPW-102). Was used.

<Drying process>
The taken-out wet cake-like aggregate was put in a vacuum dryer and dried to produce capsule toner particles (12 kg) having a volume average particle diameter of 6 μm. The particle size of the toner particles was measured using Coulter Multisizer II (manufactured by Coulter). Further, as a result of observing the obtained capsule toner with an electron microscope, no aggregate was found.

<External addition process>
100 parts by weight of the capsule toner obtained above, 0.7 parts by weight of hydrophobic silica fine particles having an average primary particle diameter of 12 nm, and 1.2 parts by weight of hydrophobized titanium oxide fine particles having an average primary particle diameter of 30 nm were added to Henschel. The capsule toner (12 kg) of Example 1 was produced by mixing for 2 minutes with a mixer.

Example 2
Except that the ratio of the α-olefin polymer (wax) used in 10 parts by weight to 100 parts by weight of the polyester resin (B) in Example 1 was changed to 20 parts by weight, it was exactly the same as in Example 1. A capsule toner was produced.

Example 3
Except that the ratio of the α-olefin polymer (wax) used in 10 parts by weight to 100 parts by weight of the polyester resin (B) in Example 1 was changed to 5 parts by weight, it was exactly the same as Example 1. A capsule toner was produced.

Example 4
In Example 1, the proportion of the α-olefin polymer (wax) used in 10 parts by weight with respect to 100 parts by weight of the polyester resin (B) was changed to 10 parts by weight, and the constituent materials were changed as shown in the following table. A capsule toner was produced in exactly the same manner as in Example 1 except that.

Comparative Example 1
A capsule toner was produced in exactly the same manner as in Example 1 except that the α-olefin polymer (wax) in the shell layer of Example 1 was changed to paraffin wax HNP-9 (Nippon Seiki Co., Ltd.).

Comparative Example 2
A capsule toner was produced in exactly the same manner as in Example 1 except that the α-olefin polymer (wax) in the shell layer of Example 1 was changed to paraffin wax HNP-19 (Nippon Seiki Co., Ltd.).

Comparative Example 3
A capsule toner was produced in exactly the same manner as in Example 1 except that the α-olefin polymer (wax) in the shell layer of Example 1 was not used.

Comparative Example 4
A capsule toner was produced in exactly the same manner as in Example 1 except that the polyester resin (B) in the shell layer of Example 1 was not used.

<Career>
The following ferrite carrier was prepared as a carrier for a two-component developer.

Ferrite raw material MgO (content: 3%), MnO (20%) and Fe ₂ O ₃ (77%) were mixed in a ball mill and calcined at 900 ° C. in a rotary kiln. Then, it was finely pulverized to a mean particle size of 2 μm or less using a steel ball as a pulverizing medium by a wet pulverizer. The obtained ferrite fine powder was granulated by a spray drying method, and the granulated product was fired at 1300 ° C. After firing, the particles are crushed using a crusher, and core particles made of a ferrite component having a volume average particle diameter of 39 μm by a laser diffraction scattering method and a volume resistivity of 1 × 10 ⁷ to 1 × 10 ⁸ Ω · cm by a bridge method are obtained. Obtained.

  Next, as a coating liquid for coating the core particles, thermosetting straight silicone resin (number average molecular weight: 12000; KR271, manufactured by Shin-Etsu Chemical Co., Ltd.) is 2.5 parts by weight with respect to 100 parts by weight of the core particles. Then, 5 parts by weight of carbon black (primary particle size 25 nm, oil absorption 150 ml / 100 g) was dissolved and dispersed in toluene with respect to the thermosetting straight silicone resin to prepare a coating solution for coating.

  The prepared coating solution is completely coated with a spray coating apparatus (SPIRA COTA (registered trademark), manufactured by Okada Seiko Co., Ltd.) for 60 minutes at 180 ° C. to completely evaporate toluene and remove the core. The particles were coated. Then, it heated at 240 degreeC and the thermosetting straight silicone resin was hardened, and the carrier with a volume average particle diameter of 40 micrometers was produced.

<Developer>
The capsule toners of Examples 1 to 4 and Comparative Examples 1 to 4 were mixed with the carrier to prepare a two-component developer. As for the mixing method, 93 parts by weight of carrier and 7 parts by weight of capsule toner were put into a Nauta mixer (VL-0, manufactured by Hosokawa Micron Corporation) and mixed by stirring for 40 minutes.

[Evaluation results]
The capsule toners of Examples 1 to 4 and Comparative Examples 1 to 4 were evaluated for low-temperature fixability, hot offset resistance, image density (after initial printing of 10K sheets), and developer fluidity. The evaluation results are shown in Table 1.

  As a machine for evaluation, a digital full-color multifunction peripheral (manufactured by Sharp: MX-4501) is used, and only the cyan image forming image forming unit is used among the four image forming units of the digital full-color multifunction peripheral. The two-component developers of Examples and Comparative Examples and capsule toner were filled in.

As development conditions, in an environment of room temperature 20 ° C. and humidity 60%, the peripheral speed of the photosensitive member is 400 mm / second, the peripheral speed of the developing roller is 560 mm / second, the gap between the photosensitive member and the developing roller is 0.45 mm, The gap of the regulating blade is set to 0.4 mm, the toner adhesion amount on paper in a solid image (100% density) is 0.5 mg / cm ² , and the toner adhesion amount in the non-image area is the smallest. The surface potential and development bias were adjusted respectively.

(Low temperature fixability)
For low-temperature fixability, prepare an unfixed image on which a solid image with a side of 3 cm is printed, and use an external fixing unit that conforms to a digital full-color multifunction peripheral (manufactured by Sharp Corporation: MX-4501) to fix the fixing nip width. Was set to 6.5 mm ± 0.1 mm, and a fixing test was conducted.
As fixing conditions, the temperature of the heat roller is set to 120 ° C., the paper after fixing is folded inward at the printing portion of the solid image, a pressure of 10 N / m ² is applied to the bent portion for 2 seconds, and then the paper is Open, image peeling width less than 0.2 mm is very good (VG: very good), image peeling width is 0.2 mm or more and less than 1 mm (G: good), image peeling Those having a width of 1 mm or more were defined as bad (B).

(Hot offset resistance)
For hot offset resistance, an unfixed image with a solid image of 3 cm on each side is prepared, and an external fixing unit conforming to a digital full-color multifunction machine (manufactured by Sharp Corporation: MX-4501) is used. The fixing test was performed with the width set to 6.5 mm ± 0.1 mm.

As fixing conditions, the temperature of the heat roller is set to 180 ° C., and the presence or absence of a solid image in which an image obtained by transferring the fixed paper to the heat roller is re-transferred to the paper is checked. An image density (ID) of less than 0.05 is very good (VG), 0.05 to less than 0.1 is good, (G) and 0.1 or more is bad (B). did.
In addition, image density (ID) measured the optical density of the evaluation image using the spectrocolorimetric densitometer (Nippon lithographic printing equipment company make: X-Rite938).

(Image density: ID)
Regarding the image density, after initial printing and 10K continuous printing, a solid solid image (100% density) with a side of 3 cm was printed at one central portion of the paper surface, and a reflection densitometer (Macbeth: RD918) was used. The density of the solid image was measured.

  It is very good (VG) if the image density (ID) is 1.4 or more (paper fiber is completely covered with toner), and good if it is 1.3 or more and less than 1.4 (G If it is less than 1.3, it was judged as defective (B).

(Developer fluidity)
The developer fluidity is evaluated by visually checking whether the developer is being smoothly conveyed by the developing roller, and when uniform spikes are formed, there is no decrease in fluidity and uniform spikes are formed. If not, it was judged that there was a decrease in liquidity.

(Comprehensive evaluation)
Overall evaluation of the above low-temperature fixability, hot offset resistance, image density (ID), and developer fluidity evaluation results is evaluated as very good (VG) or bad (B) did.
The above evaluation results are shown in the following table.

As shown in Table 1, with the capsule toners of Examples 1 to 4, excellent effects were obtained in low-temperature fixability, hot offset resistance, image density (initially after 10K continuous printing), and developer fluidity. It was.
Moreover, it was very excellent also in comprehensive evaluation.

On the other hand, the capsule toner of Comparative Example 3 cannot obtain sufficient low-temperature fixability, and the capsule toners of Comparative Examples 1 to 3 cannot obtain sufficient hot offset resistance. In the capsule toner, the fluidity of the developer was reduced.
Therefore, the overall evaluation was bad.

  According to the present invention, since the outermost shell layer of toner particles contains a hard α-olefin polymer having a low melting point, the fluidity of the developer is lowered without impairing the low-temperature fixability and the hot offset resistance. A capsule toner that can suppress the above is obtained.

Claims (12)

In a capsule toner having a core particle (A) containing at least a colorant and a polyester resin (a), and a shell layer covering the surface of the core particle,
The shell layer is a higher α-olefin polymer having a melting point of 55 ° C. to 70 ° C. obtained by polymerizing an α-olefin having 16 or more carbon atoms, and a glass transition point of 50 ° C. to 65 ° C. A capsule toner comprising a polyester resin (B).   The core particle (A) includes a polymer of phthalic acid and glycol as the polyester resin (a), and the shell layer includes a polymer of phthalic acid, glycol and bisphenol A alkoxylate as the polyester. Item 2. The capsule toner according to Item 1.   The core particle (A) contains a polymer of phthalic acid or phthalic acid ester and ethylene glycol or propylene glycol as the polyester resin (a), and the shell layer has phthalic acid or phthalic acid ester as the polyester resin (B), The capsule toner according to claim 1 or 2, comprising a polymer of ethylene glycol or propylene glycol and bisphenol A methoxylate, bisphenol A ethoxylate or bisphenol A propoxylate.   The core particle (A) contains a polymer of dimethyl terephthalate, dimethyl isophthalate, 5-sodium sulfodimethyl isophthalate, ethylene glycol and propylene glycol as the polyester resin (a), and the shell layer is a polyester resin (B). The capsule toner according to claim 1, comprising a polymer of dimethyl terephthalate, dimethyl isophthalate, ethylene glycol, and bisphenol A ethoxylate.   The capsule toner according to claim 1, wherein the shell layer contains an α-olefin polymer having 16 to 28 carbon atoms.   The capsule toner according to claim 1, wherein the shell layer contains a polymer of α-olefin having 22 and 24 carbon atoms.   The capsule toner according to claim 1, wherein the shell layer contains the α-olefin polymer in a range of 100: 5 to 100: 20 with respect to the polyester resin (B).   The capsule toner according to any one of claims 1 to 7, wherein the core particles (A) further contain petroleum wax, and the shell layer does not contain petroleum wax.   The number average particle diameter of the said core particle (A) is 2 micrometers-10 micrometers, and the number average particle diameter of the said capsule toner is 3 micrometers-11 micrometers, The capsule toner as described in any one of Claims 1-8. A step of producing an aqueous dispersion of core particles (A) having a number average particle diameter of 2 μm to 10 μm containing at least a colorant and a polyester resin (a);
Producing an aqueous dispersion of polyester resin particles (B) having a number average particle diameter of 0.05 μm to 0.5 μm;
Higher α-olefin polymer particles having a number average particle size of 0.05 μm to 0.5 μm, including an α-olefin polymer having a melting point of 55 ° C. to 70 ° C., obtained by polymerizing an α-olefin having 16 to 28 carbon atoms Producing an aqueous dispersion of (C);
The aqueous dispersion of the core particles (A), the aqueous dispersion of the polyester particles (B), and the aqueous dispersion of the higher α-olefin polymer particles (C) are mixed, and the resulting mixture is heated. Or the surface of the core particles (A) is coated with the polyester resin particles (B) and the higher α-olefin polymer particles (C) by adding a flocculant to the obtained mixed liquid. A step of forming coated particles;
And a smoothing step of heating the coated particles. The melting point of the α-olefin polymer is higher than the glass transition point of the polyester particles (B),
The manufacturing method according to claim 10, wherein the heating temperature of the coated particles in the smoothing step is not less than the glass transition point of the polyester particles (B) and not more than the melting point of the α-olefin polymer. The core particle (A) includes a petroleum wax having a melting point higher than the glass transition point of the polyester particle (B),
The manufacturing method according to claim 10 or 11, wherein the heating temperature of the coated particles in the smoothing step is not less than the glass transition point of the polyester particles (B) and not more than the melting point of the petroleum wax.

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