JP3277081B2 - Deformed resin particles, method for deforming resin particles, and electrophotographic toner comprising the deformed resin particles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for deforming resin particles, and more particularly, to a method for developing an electrophotographic developer particle for developing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing and the like. About the method of conversion.

[0002]

2. Description of the Related Art Conventionally, as a method of deforming resin particles by modifying the surface of particles, a surface modification method of attaching fine particles to the surface of main particles is known. As a specific method, in the dry method, a method utilizing mechanical energy using a Hensyl mixer, a hybridizer, a mechanofusion system or the like (JP-A-63-31264, JP-A-1
18153, Japanese Patent Application Laid-Open No. 2-146056, etc., and in the wet method, a method of fusing and fixing by electrostatic adhesion and heating (Japanese Patent Application Laid-Open No. 1-300264, Japanese Patent Application Laid-Open No. 2-880, Japanese Patent Application Laid-Open No. 5-61245). Are known.

[0003] However, these surface modification methods require non-uniformity of adhesion of fine particles and separation of non-adhered fine particles, and the surface modified particles obtained by these methods cannot be externally added due to mechanical stress. There was a problem in terms of durability, such as separation of fine particles.

[0004] In particular, for a toner for developing an electrostatic image in electrophotography, various surface modification methods and surface modified toners have been used for the purpose of achieving both low-temperature fixability as well as mechanical strength and adhesion resistance. Proposed. For example, a core (nucleus) / shell (shell) toner formed by seed polymerization is formed as a layer having a low softening point region for low-temperature fixability and a high softening point region for mechanical strength (Japanese Patent Laid-Open No. 2-61651). Etc.), an encapsulated toner obtained by an interfacial polymerization method, an internal polymerization method, an external polymerization method, etc. (Japanese Patent Application Laid-Open No. 63-19661), or a toner coated by softening fine particles added to the surface of main particles (Japanese Patent Application Laid-Open No. 1-185650). Etc.) are known. However, in these methods, the high softening point resin constituting the shell is required to have a certain thickness and hardness in order to maintain mechanical strength, and a high fixing temperature is required due to the influence of the shell during fixing. There was a problem of worsening the sex.

Further, a toner in which fine particles having a high softening point are thermally fused to main particles having a low softening point by a dry or wet method (JP-A-56-6856, JP-A-3-1709)
No. 45) is known, but the adhesion in the region where materials having different softening points are joined is further weakened, and there has been a problem in toner life such as separation of fine particles and generation of fine powder due to mechanical stress.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for deforming resin particles by surface modification, which uniformly reforms the particle surface and does not require a separation operation for unexternally added fine particles. Is to do.

Another object of the present invention is to provide a method for producing an electrophotographic toner by surface modification, which has both the mechanical strength and the adhesion resistance required for an electrophotographic toner and the low-temperature fixability of main particles at the same time.

[0008]

In order to solve the above-mentioned problems, the present invention (claim 1) relates to a method for producing primary particles, attached particles in an aqueous system .
In the presence of an addition- polymerizable monomer, a dispersant having a hydrophobic group having a skeleton of the addition- polymerizable monomer, and a water-soluble polymerization initiator, | (Zeta potential of main particles) | ≦ 20 mV Yes,
And the monomer is polymerized on the surface of the main particle in a pH range where ｛| (zeta potential of dispersant) | − | (zeta potential of main particle) |｝ ≧ 10 mV. Provided is a method for deforming resin particles by modification.

In this deforming method, it is preferable that the stable polarity of the dispersant in the aqueous solution is the same as that of the main particles.

[0010] The present invention (claim 3) provides an aqueous system comprising a main particle, a polymerizable monomer, a dispersant having a hydrophobic group having a skeleton of the polymerizable monomer, and a water-soluble polymerization initiator. In the presence, in the pH range where | (Zeta potential of main particles) | ≦ 20 mV and ｛| (Zeta potential of dispersant) | − | (Zeta potential of main particles) |｝ ≧ 10 mV, The present invention provides deformed resin particles, wherein the surface of the main particles is modified by polymerizing the monomer on the surface of the main particles.

Further, the present invention comprises modified resin particles in which a plurality of polymers having a softening point different from the softening point of the main particles are partially formed by polymerization on the surface of the main particles containing the colorant. Wherein at least a part of a temperature-complex viscoelasticity curve of the main particles and the deformed resin particles overlaps, and a straight line enclosing outlines of the plurality of polymers does not intersect the outer periphery of the main particles. And a toner for electrophotography.

Further, the present invention provides a toner for electrophotography in which the polymer has a triangular cross section, so that sticking resistance due to the problem of mechanical strength has been solved.

[0013]

In the method of the present invention, polymerization is carried out in the presence of main particles, a dispersant, a polymerizable monomer, and a water-soluble polymerization initiator in an aqueous system. , Seed polymerization, wherein the hydrophobic group of the dispersant has a polymerizable monomer skeleton, and | (zeta potential of main particles)
| ≦ 20 mV and Δ | (zeta potential of dispersant) | − |
(Zeta potential of main particles) | p such that｝ ≧ 10 mV
By polymerizing in the H region, seed polymerization does not occur,
The surface modification similar to the externally added fine particle structure causes deformation of the resin particles.

Further, in the method of the present invention, polymerization growth occurs based on the dispersant swollen on the surface of the main particles, so that particles having excellent mechanical strength and having a uniformly modified surface can be obtained. Of course, a surface modification similar to the fine particle externally added structure occurs, but it is not necessary to separate unexternally added particles. Further, regardless of whether the stable polarity of the dispersant in the aqueous solution and the stable polarity of the main particles are the same or different, the resin particles obtained by the surface modification of the present invention can be obtained by adjusting the pH.

In the present invention, the main particles having a plurality of polymers grown from the polymerizable monomer on the surface of the main particles containing the colorant are formed into irregular shaped particles by surface modification, and the main particles have a low softening point. When the toner has a structure having a high softening point, and the temperature-complex viscoelasticity curve of the irregularly shaped particles and the main particles by surface modification at least partially overlaps, Low-temperature fixability than that of the surface coating type structure,
A low-temperature fixing toner excellent in mechanical strength and life can be obtained.
Further, as the form of the polymer, a triangular cross section, a tumor shape, a dendritic shape, or the like can be obtained, but in order to satisfy mechanical strength and low-temperature fixability, the cross section is desirably substantially triangular. By allowing a large number of polymers to be present so that the straight lines enclosing the outer contours on the outer peripheral side of the plurality of polymers do not intersect with the outer periphery of the main particles, external stress is not applied to the main particles having a low softening point. As a result, the sticking resistance can be improved.

[0016]

The present invention will be described below in detail with reference to examples of the present invention.

In the method of the present invention, the polymerizable monomers used for the polymerization for modifying the surface of the main particles include vinyl aromatic monomers, acrylic monomers, vinyl ester monomers, Examples include vinyl ether monomers, diolefin monomers, and monoolefin monomers.

Among them, monovinyl aromatic monomers include monovinyl aromatic hydrocarbons such as styrene, α-methylstyrene, vinyltoluene, α-chlorostyrene, o-, m- and p-chlorostyrene. , P-ethylstyrene and divinylbenzene alone or in combination of two or more.

Examples of the acrylic monomer include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, hexyl methacrylate, and methacrylic acid. 2-ethylhexyl, β-hydroxyethyl acrylate, γ-hydroxyacrylate, propyl δ-hydroxyacrylate, ethyl β-hydroxymethacrylate, ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, and the like. I can do it.

Examples of the vinyl ester monomer include vinyl formate, vinyl acetate, vinyl propionate and the like. Examples of the vinyl ether monomer include vinyl methyl ether, vinyl ethyl ether, vinyl-n-butyl ether, vinyl phenyl ether, and vinyl cyclohexyl ether. Examples of the diolefin-based monomer include butadiene, isoprene, chloroprene and the like. Monoolefin monomers include ethylene, propylene, isobutylene, butene-1, pentene-1,
4-methylpentene-1 and the like.

The dispersants used in the method of the present invention include:
Any dispersant having a hydrophobic group having a repeating structure of the above-described polymerizable monomer skeleton or two or more copolymer skeletons may be used. Among them, those having a polar group of a weak acid or a weak base include, for example, anionic fatty acid salt type -C
OONH ₄ etc., -OSO3NH of sulfuric acid ester salt type
_{And the} like, such as phosphoric acid ester salt type -OPO ₃ (NH ₄ ) ₂ , and cationically amine salt type 1,2,3 tertiary alkylamines, 1,2,3 tertiary ethanolamines, polyethylenepolyamine And ethylene oxide adducts of alkylamines, which are polarized by weak hydration in water and exhibit weak cationicity.

[0022] Specific examples of the dispersant, _CH 2 _{= (CH} 2) as having a styrene derivative structural n-CH
CH ₂ ＣＯCR ₁ COO (CH ₂ ) n-NR ₂ having an acrylic acid derivative structure such as — 、 — COONH ₄
CH ₃ ＣＲCR ₁ COO (CH ₂ ) _n CH as those having a styrene acrylic acid copolymer derivative structure such as R _3
2 = CH- ◎ -OSO ₃ NH _{4 and the} like. In addition,
In the formula, n represents an integer of 1 to 10, R ₁ , R ₂ , and R ₃ represent an alkyl group having 1 to 6 carbon atoms , and ◎ represents a benzene ring. Shown below
The same is true for the formula.

In particular, when moisture resistance and water resistance are taken into consideration, it is desirable to select a material having high volatility such as ammonia ion or amine ion and a weak acid such as acetic acid or formic acid for neutralization. The dispersants used in the method of the present invention are not limited to those described above. The molecular weight of the hydrophobic group is preferably several hundreds to several tens of thousands in terms of weight average molecular weight, since it does not form associated micelles as in a normal emulsifier and becomes a micelle by itself.
The amount of the dispersant used is 0.01 to 30% by weight of the solid content, and preferably 0.1 to 30% by weight, since the effect of moisture resistance and water resistance due to the residual is less than that of ordinary emulsifiers, surfactants and polymer electrolytes. １５15% by weight.

Examples of the polymerization initiator used in the method of the present invention include a hydrogen peroxide solution and a redox initiator. Also, as a reactive emulsifier, as a reactive surfactant, ammonium persulfate whose decomposition section is anionic,
Examples thereof include persulfates such as sodium persulfate and potassium persulfate, cationic DEAM (N, N'-diethylaminoethyl methacrylate), and AIBN.2HC1 (isobutylamidohydrochloric acid). Other than these, polyoxyethylene methacrylate, dimethylaminoethyl, acetate of dimethylaminoethyl methacrylate and the like can be mentioned. The amount of the polymerization initiator used is 0.001 to 10% by weight with respect to the polymerizable monomer in order to completely polymerize the polymerizable monomer.
Preferably it is 0.01 to 5% by weight.

As the main particles used in the method of the present invention, various latexes, pulverized toners, polymerized toners and the like can be used, and these may be commercially available or synthesized. As a raw material of the main particles, at least the polymerizable monomer used in the present invention described above is used alone or in combination of two or more kinds and the like and a colorant is polymerized in the presence of a polymerization initiator or the like. Or a mixture prepared by kneading and pulverizing a colorant with a binder or a combination of two or more of the polymerizable monomers used in the present invention.

Specifically, for example, polystyrene, styrene-acrylic copolymer, styrene-methacrylic acid copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, polyethylene, polypropylene, polyurethane, polyester resin, Epoxy resin,
Silicon resin, polyamide, paraffin and the like can be given.

The polymer constituting the main particles preferably has a weight average molecular weight of 10,000 to 500,000, and a softening point of 60 to 500,000.
-100 degrees is preferred. The size is 1 in average particle diameter.
１００100 μm, preferably 2-20 μm.

As the pigment of the coloring agent used in the method of the present invention, inorganic pigments (natural, chromate, ferrocyanide, oxide, chloride, sulfate, silicate, metal powder, etc.), organic pigments ( Natural dye lakes, nitroso-based, azo-based, phthalocyanine-based, condensed polycyclic, basic dye lakes, mordant dyes, vat dyes, etc.), and dyes include water-soluble dyes and oil-based dyes. As specific examples of the inorganic pigment,
For example, natural pigments such as ocher, graphite, zinc yellow,
Chromates such as barium yellow, chrome orange, molybdenum red and chrome green; ferrocyan compounds such as navy blue; titanium oxide, titanium yellow, titanium white,
Bengala, yellow iron oxide, zinc ferrite, zinc white, iron black, cobalt blue, chromium oxide, oxide such as spinel green, cadmium yellow, cadmium orange,
Examples thereof include sulfides such as cadmium red, sulfates such as barium sulfate, calcium silicate, silicates such as ultramarine, metal powders such as bronze and aluminum, and carbon black.

Specific examples of the organic pigment include, for example, natural lakes such as Madalake, nitroso pigments such as naphthol green and naphthol orange, benzidine yellow G, Hanza yellow G, Hanza yellow 10G, Vulcan orange, lake red R, and lake. Red C, Lake Red D, Watching Red, Brilliantamine 6
B, pyralozone orange, Bordeaux 10G, soluble azo type such as (Bonmaroon), pyralozone red, para red, toluidine red, ITR red, toluidine red (Rake Red 4R), toluidine maroon, brilliant fist scar red, Rake Bordeaux 5B, etc. Azo pigments such as insoluble azo and condensed azo pigments, phthalocyanine blue, phthalocyanine green, brominated phthalocyanine green, phthalocyanine pigments such as fast sky blue, anthraquinones such as sllen blue, perylenes such as perylene maroon, and perinone orange. Condensed polycyclic pigments such as perinones such as quinacridone, quinacridone such as dimethylquinacridone, dioxazines such as dioxazine violet, isoindoline and quinophthalone, and loaders 6B, lake, rhodamine lake B, basic dye lakes such as malachite green, mordant dye pigments such as alizarin lake, vat dye pigments such as indathrene blue, indigo blue, anthantrone orange, fluorescent pigments, azine pigments (Diamond black) green gold and the like.

Specific examples of water-soluble dyes include, for example, basic dyes such as rhodamine B, acid dyes, fluorescent dyes, and the like. Specific examples of oil-soluble dyes include Fast Orange R,
Monoazo dyes such as oil red and oil yellow; anthraquinone dyes such as anthraquinone blue and anthraquinone violet; azine dyes such as nigrosine and indulin; basic, acidic, and metal complex compound dyes.

Examples of the wax used in the toner of the present invention include low molecular weight polyethylene, low molecular weight polypropylene, paraffin and the like. Emulsion-type carboxyl group-modified polyolefins include ethylene, propylene, butene-1, and pentene-1.
It is also possible to use a polyethylene wax, a polypropylene wax, or the like, which is modified so as to have a carboxyl group with an olefin unit as a skeleton, and at least a part of the carboxyl group is neutralized with ammonia or an amine. The amount of the wax used is usually 0 to 30% by weight, preferably 1 to 30% by weight.

As the charge control agent, an electron donating substance such as a nigrosine dye or a quaternary ammonium salt is used as a negative charge control agent, and an electron withdrawing substance such as a metal salt of a monoazo dye is used as a positive charge control agent. Can be mentioned.

Further, an external additive is used for improving the fluidity of the toner, improving the environmental stability of the charge amount, improving the cleaning property, removing deposits on the photoreceptor, and the like. Are metal oxides such as silicon oxide, titanium oxide, zinc oxide, aluminum oxide, tin oxide, indium oxide, and cerium oxide; fatty acid metal salts such as zinc stearate, calcium stearate, and lead stearate; and barium titanate. Inorganic substances such as strontium titanate and basic bismuth acetate; PMMA; styrene-acrylic copolymers; vinylidene fluoride; and fluororesins such as tetrafluoroethylene. The use of an external additive in the toner according to the present invention can further impart mechanical strength and friction resistance.

In the method for deforming resin particles by surface modification according to the present invention, the charged amount of solids is in the usual range of 1 to 30% by weight, preferably 2 to 20% by weight. The average particle diameter of the toner is 1 to 100 μm.
m, preferably 2 to 20 μm. The polymerization temperature and time may be those known in the art. Generally, polymerization at a temperature of 40 to 100 ° C. for 1 to 50 hours is sufficient. According to the method of the present invention, the rate of generation of new particles is extremely low. .

The present inventors usually use a dispersant having a hydrophobic group having a polymerizable monomer skeleton as a dispersant in a method in which main particles are swelled with a polymerizable monomer to form seed polymerization. And, when the zeta potential of the main particles is lower than that of the dispersant, the polymerizable monomer is not the main particles, and the hydrophobic group of the dispersant is swollen by the polymerizable monomer, and seed polymerization does not occur. Further, the present inventors have found out that a polymerizable monomer grows on the surface of the main particles with a dispersant as a base, thereby synthesizing modified particles modified with a plurality of polymers, thereby leading to the present invention.

FIG. 1 is a flow sheet diagram of the method for deforming resin particles by surface modification according to the present invention. Describing along this flow sheet, first, the zeta potential of the main particles and the dispersant is measured, and the relationship between the zeta potential and the pH is determined. Based on this result, the pH of each dispersion is adjusted and mixed. This operation is most important for realizing the surface modification of the present invention without performing seed polymerization.

Next, a polymerizable monomer is added, a water-soluble polymerization initiator is added immediately before the polymerization, and wet surface modified particles are obtained by surface modified polymerization. In the method of the present invention, since the main particles, dispersant, polymerizable monomer, and polymerization in the presence of a water-soluble polymerization initiator in an aqueous system, the main particles are usually swollen with the polymerizable monomer, and the In this case, the hydrophobic group of the dispersant has a polymerizable monomer skeleton, and |
(Zeta potential of main particles) | ≦ 20 mV, and Δ |
(Zeta potential of dispersant) |-| (Zeta potential of main particles)
By polymerizing in the pH region where |｝ ≧ 10 mV, seed polymerization does not occur, and surface modification polymerization similar to the externally added fine particle structure occurs. This means that when the zeta potential of the main particles is lower than that of the dispersant, the polymerizable monomer swells the dispersant, which is not the main particles but is easily swelled because the hydrophobic group has a polymerizable monomer skeleton. It seems that seed polymerization does not occur.

Here, if the zeta potential of the main particles exceeds 20 mV, the polymerizable monomer alone swells into the main particles, seed polymerization occurs preferentially, and the surface modification of the present invention is not performed. Will be enough. In addition, when the zeta potential of the dispersant is not higher than the main particles alone by 10 mV or more, even when the zeta potential of the main particles is 20 mV or less, the polymerizable monomer does not sufficiently swell to the hydrophobic groups of the dispersant, and seed polymerization may occur. Simultaneously, it means that the surface modification of the present invention is insufficient.
Therefore, for the first time at the pH of the zeta potential in a region that satisfies both conditions, the polymerizable monomer is selectively swollen by the dispersant hydrophobic group instead of the main particle, and the surface-modified polymerization of the present invention is realized instead of the seed polymerization. .

Next, with reference to FIG. 2, how to determine an appropriate pH range in polymerization from the results obtained by measuring the zeta potential of the main particles and the dispersant will be described. FIG.
The curve of (a) is an example of the following Example 1-1, and a curve 301 is a zeta potential curve of the main particle 1 and a curve 302.
Is the zeta potential curve of Dispersant 1, which is an example in which the polarity of the main particles and the stable polarity of the dispersant are different.

First, the absolute value of the zeta potential of the main particles is 20
Search for a pH region below mV. In this example, pH 10
It is as follows. Next, when a pH region in which a value obtained by subtracting the absolute value of the zeta potential 301 of the main particles 1 from the absolute value of the zeta potential 302 of the dispersant 1 is 10 mV or more is found, the pH becomes 6 or less. In the system of the main particles 1 and the dispersant 1, a pH of 6 or less that satisfies both conditions is an appropriate pH adjustment region.

Similarly, the curve shown in FIG.
2, curve 304 is the same zeta potential curve of main particle 1 as curve 301, and curve 305 is the zeta potential curve of dispersant 2, which is an example of a dispersant having the same stable polarity as the main particles. . First, the absolute value of the zeta potential of the main particles is 20 m
Search for a pH region below V. In this example, the pH is 10 or less. Next, a search is made for a pH region in which the value obtained by subtracting the absolute value of the zeta potential 305 of the main particles 1 from the absolute value of the data potential 304 of the dispersant 2 is 10 mV or more.
Becomes In the system of the main particles 1 and the dispersant 2, pH 3 to 7
Is an appropriate region for pH adjustment.

FIG. 3 is a conceptual diagram of the irregularly shaped particles obtained by deforming the resin particles by the surface modification of the present invention and the electrophotographic toner of the present invention 2. FIG. 3A is a schematic view of a cross section of the surface-modified particles 401, wherein reference numeral 402 denotes main particles, and 403 denotes a polymer grown from a polymerizable monomer.
As is clear from FIG. 3A, since the polymer 403 is polymerized and grown on the surface of the main particle 402, the conventional dry type
The surface of the main particles 402 can be more uniformly modified as compared with the wet external addition of fine particles, the mechanical resistance and the crush resistance are excellent, and the step of separating the non-external additive particles can be simplified.

FIG. 3B is a schematic view of a cross section of the surface-modified toner 404. Reference numeral 405 denotes main particles, and a pulverized or polymerized toner can be used. When a polymerized toner is used, there is an advantage that a series of operations can be performed in a wet manner. Reference numeral 406 denotes a polymer having a substantially triangular cross section grown from a polymerizable monomer on the surface of the main particle, and has excellent mechanical strength and crush resistance for the same reason as in FIG. In order to provide low-temperature fixability together with mechanical strength, the main particles 405 have a low softening point (60 to 11).
0 degree), and the growing polymer 406 grows with a high softening point (110 to 150 degrees),
Compared to a surface-modified shell with a high softening point in the form of a coat,
Shows excellent low-temperature fixability.

Reference numeral 407 denotes an outer shape of the outer periphery of the plurality of polymers on the surface of the main particles. By preventing the outer shape from intersecting with the outer periphery of the main particles, the design of the main particles in the low-temperature fixing toner is prevented. Even if a material having a low softening point is used as 405, excellent fixing resistance is exhibited.

FIG. 3C shows another example of the resin particles whose surface has been modified by the method of the present invention. Reference numeral 408 indicates a main particle, and 409 indicates a polymer grown from a polymerizable monomer in a dendritic manner. Such a form occurs when both anionic and cationic dispersants are used, but the polymer 409 grows longer on the surface than the polymer 406, and in this case, it is uniform and crush-resistant. It is difficult to obtain a good toner,
There is a possibility of fine morphology control by polymerization growth on the main particle surface, which is an interesting result.

FIG. 4 shows an electron micrograph of the electrophotographic toner produced by the method for deforming resin particles of the present invention. FIG. 4A shows a toner having both low-temperature fixability, mechanical strength, and sticking resistance. FIG. 4 (b) is the same as FIG.
The resin particles were obtained under the same conditions as those for obtaining the resin particles shown in (1), and a long elongated polymer was observed, indicating that the polymer was polymerized and grown from the surface.

FIG. 5 shows a temperature-complex viscoelasticity curve of the toner according to the present invention and a conventional surface-modified toner. In the figure,
A curve a is a temperature-complex viscoelastic characteristic of the main toner, a curve b is a temperature-complex viscoelastic characteristic of the toner obtained in Example 2-1 described later, and a curve c is a characteristic of the toner obtained in Comparative Example 2-1 described later. Temperature-complex viscoelasticity is shown. The characteristics shown in FIG. 5 were obtained at a heating rate of 2 ° C./min using an MR-3 solid meter (manufactured by Rheology) as an apparatus.

As is apparent from FIG. 5, in Example 2-1, the curve a of the main particles and the curve b of the surface-modified particles were 130 ° C.
It overlaps around. However, in the dry or wet method of externally adding fine particles or the Coachule method, since the high softening point region and the low softening point region are not continuous, in Comparative Example 2-1, the curve c does not overlap the main particles to the end. In particular, it can be seen that in the core-shell method, in particular, this becomes remarkable, the viscoelasticity changes slowly, and a problem occurs in the fixing property.

FIG. 6 illustrates a color image forming apparatus using the electrophotographic toner of the present invention. In the apparatus shown in FIG. 6, the photoconductor 201, the charging device 202, the laser exposure device 203, the developing device 200, the transfer device 209, the blade cleaning device 204, and the discharging lamp 205 are black.
Four sets are arranged for four colors of yellow, magenta, and cyan. A transfer material 213 such as paper or an OHP sheet is conveyed on the transfer belt 208 from the direction of the arrow, and a transfer voltage is applied by the transfer device 209 from below the transfer belt 208 at a portion where the transfer material 213 contacts the photoconductor 202. The toner developed on the photoconductor 202 is transferred to the transfer material 213. This is sequentially performed for each color, and the toner image is superimposed on the transfer material 213. As the transfer device 109, a device that applies a bias voltage to an elastic roller or the like is used. The toner image superimposed on the transfer material 213 passes between the heating roller 211 and the pressure roller 212 in the fixing device 210, so that heat is applied to the toner and is fixed on the image support. Thus, a full-color image is obtained.

The toner according to the present invention has a surface temperature of 128 ° C.
Used for the developer of a printer equipped with a heat roller heat fixing unit (nip width 7.5 mm) and a blade cleaning device, with a process speed of 105 mm / sec.
Image output of lines and patches of 20 mm square solid black and halftone dots was performed. Further, a ferrite carrier having an average particle diameter of about 60 μm is mixed at a weight ratio of 100: 4, and a two-component developing device, a heat roller heat fixing device having a surface temperature of 128 ° C. (nip width: 7.5 mm), and a blade cleaning device are provided. An image was output in the same manner as described above, using the toner as a developer for a printer having a process speed of 65 mm / sec. For the obtained image, the image density of the solid black patch was measured with a MACBETHR918 reflection densitometer, and the following evaluation was performed.

1. Mechanical strength and crushing resistance (fine powder rate) After printing a certain number of sheets at a printing rate of 6%, judgment was made based on the presence or absence of a character memory or a streak-like defective image on the image.
After printing 30,000 sheets, the particle size of the developer in the developing device was measured by a particle counter (CAPA-700, manufactured by HORIBA, Ltd.). When the ratio (fine powder ratio) increased by 5% or more, it was evaluated as x, and when less than 5%, it was evaluated as ○.

2. Test in the developing device (number of running sheets) SEM observation of the surface of the developing roller and the charging blade was performed, and it was determined whether or not the toner was fixed on the charging blade and the developing roller. When no adhesion was observed in the developing device even after printing 30,000 sheets, ○ was given, and when adhesion was observed and image uniformity was deteriorated, x was given. Also,
Here, the number of running sheets indicates how many sheets have been developed before fixing occurs.

3. Viscoelasticity test The sharpness of the change in viscoelasticity with respect to the temperature of the main particles and the irregularly shaped particles due to the surface modification was compared and used as an index of low-temperature fixability. The dynamic viscoelasticity of the obtained particles and the main particles was measured with an MR-3 solid meter (manufactured by Rheology Co., Ltd.). The case where they do not overlap is indicated by x.

4. Fixing test The toner fixing portion was rubbed with a fastness tester under the condition of 300 cloths, and the image density before and after the test was measured with a reflection densitometer, and the ratio was evaluated. 90% image density ratio before and after the test
The above was evaluated as ○, and less than 90% was evaluated as ×. Further, the fixing rate here is the ratio of the image density.

Hereinafter, specific examples of the present invention will be described. Unless otherwise specified, quantities are indicated by weight.

Example 1-1 Synthesis of Surface-Modified Particles Base particles 1 (PT-82 toner manufactured by Toshiba, volume average particle diameter 10.0 μm) 0.2 parts by weight Dispersant 1 (structural formula CH ₂ = CR ₁ COO) (CH ₂ ) n-NHR ₂ R ₃ ) 0.006 parts by weight Styrene 0.16 parts by weight n-butyl acrylate 0.04 parts by weight Ammonium persulfate 0.006 parts by weight Deionized water 200 parts by weight According to the flow chart of FIG. FIG. 2 (a) shows a curve obtained by measuring the relationship between the pH of the above main particles and the dispersant and the zeta potential using MODEL501 manufactured by PENKEM. Suitable PH area is PH
Since it is 6 or less, the main particles and the dispersion were adjusted to pH 5 with an aqueous hydrochloric acid solution. Next, 2 liters of this dispersion was transferred to a four-necked flask, and styrene and n-butyl acrylate as polymerizable monomers were added. Then, ammonium persulfate as a polymerization initiator was added, and while stirring at 80 rpm, the temperature was set to 70 ° C., and polymerization was carried out for 8 hours.

The obtained surface-modified particles had a volume average particle size of 1
It was 0.1 μm. Surface condition made by TOPCON AB
Observation with a T-32 type SEM revealed that the obtained particles were not spherical and had a smooth surface like particles obtained by seed polymerization, but were not uniformly covered with fine particles as shown in FIG. It was found that the surface was modified.

The particles were further subjected to Hitachi H-600 type T
When the cross section was observed by EM, fine particles did not adhere, and no interface between the polymer having a small surface and the main particles was observed. Also, no single fine particles or polymer was found. From this, it is considered that a fine polymer was formed by the growth polymerization of the polymerizable monomer from the polymerization active site on the main particle surface. From this, it can be expected that the obtained particles have excellent mechanical strength and crush resistance. When evaluated by the method described above, the fine powder ratio is 1
% And very excellent results were obtained.

Example 1-2 Cationic Dispersant (Structural Formula CH ₂ ＣＲCR ₁ COO (C
Instead of H ₂ ) _n -NHR ₂ R ₃ ), the polar group is anionic but the hydrophobic group is CH ₂ （(C) as a dispersant 2 having a styrene polymer derivative structure having the same skeleton as the polymerizable monomer.
H ₂ ) _n -CH- ◎ -COONH ₄ , except that the volume average particle diameter was 10.1 in the same manner as in Example 1-1.
μm particles were obtained. ｛| (Zeta potential of dispersant) |-|
(Zeta potential of main particles) |｝ ≧ 10 mV, and |
(Zeta potential of main particles) | p satisfying ≦ 20 mV
As shown in FIG. 2 (b), the suitable region for H is pH 3-7.
Therefore, the pH was adjusted to 7 with aqueous ammonia for polymerization.

When the state of the surface was observed by SEM, the polymer on the surface of the main particles was slightly larger than that in Example 1-1. However, as shown in FIG. Such particles were obtained, and no single polymer was observed. As a result of TEM observation, the cross-sectional shape of the fine polymer on the surface was substantially triangular and more rounded than in Example 1-1, and no interface with the main particles was observed.
When a mechanical strength and crush resistance test was performed, the fine powder ratio was 1% or less, and extremely excellent results were obtained.

Examples 1-3, 4 When adjusting the pH, the procedure of Example 1 was repeated except that the pH was adjusted to pH 6 and pH 2, which are appropriate pH ranges, using aqueous ammonia and hydrochloric acid, respectively, instead of pH 5.
-1 in the same manner as -1.
m particles were obtained. From FIG. 2A, at pH 6, the absolute value of the zeta potential of the main particles was 20 mV, and the difference between the absolute value of the dispersant and the absolute value of the main particles was 10 mV. Also,
At pH 2, the absolute value of the zeta potential of the main particles was 0 mV, and the difference between the absolute value of the dispersant and the absolute value of the main particles was 40 mV.
V. That is, ｛| (zeta potential of dispersant) |
− | (Zeta potential of main particles) |｝ ≧ 10 mV and polymerization is performed by adjusting the pH to another value within the range of | (Zeta potential of main particles) | ≦ 20 mV. .

The state of the surface of the obtained particles was observed by SEM. As a result, as shown in FIG. 4 (a), particles having fine particles were obtained. The result of TEM observation was the same. The fine polymer on the surface had a triangular pyramid shape, no interface with the main particles was observed, and no single polymer was observed. When a mechanical strength and crush resistance test was performed, the fine powder ratio was 2% and 3%, and extremely excellent results were obtained.

Comparative Example 1-1 In Example 1-1, the following fine particles were externally added to the main particles to obtain dry surface modified particles.

Synthesis of Polystyrene Acrylate Fine Particles Styrene 0.16 parts by weight N-butyl acrylate 0.04 parts by weight Ammonium persulfate 0.006 parts by weight Ion exchange water 200 parts by weight Ion exchange water was adjusted to pH 9.8 with ammonia water. This was transferred to a 2 liter four-necked flask, to which styrene and n-butyl acrylate were added, ammonium persulfate was further added, and the temperature was raised to 70 while stirring at 200 rpm.
And the polymerization was carried out for 8 hours. The obtained particles had a volume average particle size of 0.3 μm. 0.1 part by weight of the polystyrene acrylate fine particles was added to 1 part by weight of the main particles of Example 1-1, and a hybridizer system (HYBRI) was added.
DIZER NHS-0 (manufactured by NARAKIKAI) at a rotation speed of 1200 rpm for 10 minutes to obtain dry surface modified particles.

When the state of the surface was observed with a SEM, many externally non-uniform particles were obtained.
Further, non-externally added particles of polystyrene acrylate were also observed. As a result of TEM observation, polystyrene on the surface was often embedded in the main particles, but the interface with the main particles was discontinuous. Desorbed ones were observed. From these facts, it is expected that this method requires the separation and collection of non-externally added fine particles, and also has problems in mechanical strength and crush resistance. In the mechanical strength / crush resistance test, the fine powder ratio was 12%, which was a very bad result.

Comparative Example 1-2 Surface modified particles were obtained by externally adding the following fine particles to the main particles in a wet manner in Example 1-1.

Synthesis of Polystyrene Acrylate Fine Particles Styrene 0.16 parts by weight nbutyl acrylate 0.04 parts by weight AIBN.2HC1 (isobutylamide hydrochloric acid) 0.006 parts by weight Ion-exchanged water 200 parts by weight First, ion-exchanged water Was adjusted to pH 9.8 with aqueous ammonia, and then transferred to a 2 liter four-necked flask,
Add styrene and n-butyl acrylate, and add AIBN
2H1 was added, the temperature was set to 70 ° C. while stirring at 200 rpm, and polymerization was carried out for 8 hours. The volume average particle size of the obtained particles was 0.2 μm.

A dispersion of 0.05 part by weight of the positively chargeable polystyrene acrylate fine particles was added to 1 part by weight of the main particles of Example 1-1, and the mixture was mixed by ultrasonic waves to adhere the fine particles to the main particles. Thereafter, the mixture was heated to 98 ° C. and fused, and surface modified particles were obtained by a general wet external addition.

When the state of the surface was observed by SEM, many externally polystyrene fine particles having non-uniform states were obtained. Also, non-externally added particles of polystyrene were observed. As a result of TEM observation, most of the fine particles on the surface were embedded in the main particles, but since the interface with the main particles was intermittent, polystyrene acrylate fine particles were removed from the main particles when preparing ultrathin sections of the TEM. Separation was observed. From these facts, it is expected that this method requires the separation and collection of non-externally added fine particles, and also has problems in mechanical strength and crush resistance. When a mechanical strength and crush resistance test was performed, a poor result was obtained with a fine powder ratio of 10%.

Comparative Example 1-3 Example 1 was repeated except that the pH of the dispersion mixture of the main particles 1 and the dispersant 1 was adjusted to pH 11 with aqueous ammonia.
In the same manner as in -1, surface-modified particles were obtained. From FIG. 2A, at pH 11, the absolute value of the zeta potential of the main particles is 25 m
V, and the difference between the absolute value of the dispersant and the absolute value of the main particles is 10
mV. That is, ｛| (zeta potential of dispersant)
|-| (Zeta potential of main particles) |｝ ≧ 10 mV;
Although this point is within the scope of the present invention, | (zeta potential of main particles) |> 20 mV, which means that the polymerization was performed by adjusting the pH to a range outside the scope of the present invention. When the state of the surface was observed by SEM, particles having a smooth surface were obtained by ordinary seed polymerization, and FIG.
No particles of the present invention as shown in Table 2 were obtained.

Comparative Example 1-4 Surface-modified particles were obtained in the same manner as in Example 1-1, except that the pH of the dispersion mixture of the main particles 1 and the dispersant 1 was adjusted to pH 8 with aqueous ammonia. At pH 8, the absolute value of the zeta potential of the main particles was 18 mV, and the difference between the absolute value of the dispersant and the absolute value of the main particles was 7 mV. That is, | (Zeta potential of main particles) | ≦ 20 mV, which is within the scope of the present invention, but || (Zeta potential of dispersant) | − | (Zeta potential of main particles) |｝ < 10 mV, and in this respect the pH is outside the scope of the invention.
Is adjusted to polymerize. When the state of the surface was observed by SEM, the surface was somewhat rougher than the normal seed particles, but particles with a distinct surface modification as shown in FIG. 4A were not obtained.

Comparative Example 1-4 Example 1 was repeated, except that sodium dodecylbenzenesulfonate in which the hydrophobic group of the dispersant did not have the same skeleton as the polymerizable monomer was used in place of the anionic dispersant. When polymerization was carried out in the same manner as in Example 2, aggregation occurred, and no particles were obtained. This result is presumably because the hydrophobic group of the dispersing agent did not have the same skeleton as the polymerizable monomer, so that the swelling ability was low and the dispersion stability of the polymerizable monomer could not be obtained.

Example 2-1 Synthesis of Main Particles (Polymerized Toner) Styrene monomer 50 parts by weight butyl acrylate 30 parts by weight Styrene-acrylate latex 12 parts by weight Ammonium persulfate 1 part by weight Azobisisobityronitrile 1 part by weight Carbon Black 4 parts by weight Quaternary ammonium salt-based negative charge control agent (CCA) 1 part by weight Polypropylene wax 1 part by weight A ball mill (HD pot mill type A)
-3 (manufactured by Nitsuka Corporation) for 40 hours. K. The mixture was stirred with an AUTO homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) for 15 minutes at a rotation speed of 14000 rpm, transferred to a 2 liter four-necked flask containing ion-exchanged water, and further stirred at 1000 rpm for 2 hours, and then 250 rpm
m, the temperature was set to 70 ° C., and polymerization was carried out for 8 hours to obtain a spherical polymerized toner having a volume average particle diameter of 8.0 μm and a softening point of 100 ° C. and a smooth surface.

Synthesis of Surface Modified Particles Main particles (the above-mentioned polymerized toner) 0.2 parts by weight Dispersant (structural formula CH ₂ = CR ₁ COO (CH ₂ ) _n -NHR ₂ R ₃ ) 0.006 parts by weight Styrene 0.19 parts by weight n-butyl acrylate 0.01 parts by weight Ammonium persulfate 0.006 parts by weight Ion-exchanged water 200 parts by weight According to the flow chart of FIG. 1, the relationship between the pH of the main particles and the dispersant and the zeta potential is determined by PENKEM. As a result of the measurement using Model 501, a graph as shown in FIG. 2A was obtained. Here, the dispersant is the same, and the main particles are p
It started rising from H5 to the plus side. Therefore, p
The H region has a pH of 5 or less, and the pH was adjusted to 4 with an aqueous hydrochloric acid solution.

Next, the dispersion was transferred to a 2 liter four-necked flask, styrene and n-butyl acrylate were added, ammonium persulfate was added, the mixture was stirred at 80 rpm, and the temperature was set at 70 ° C. Polymerization was carried out for hours. The obtained surface-modified particles had a volume average particle size of 8.2 μm. Surface condition is TOPCON ABT-32 type SEM
As a result, the main particles were initially spherical and the surface was smooth. However, the obtained particles did not have a smooth surface like the particles obtained by seed polymerization, and the uniform fine particles shown in FIG. The particles were found to be irregular shaped particles whose surfaces were modified as if they had been dusted.

The particles were further subjected to Hitachi H-600 type T
When the cross section was well observed by EM, fine particles were not attached but the cross-sectional shape of the fine polymer on the surface was substantially triangular, and no interface with the main particles was observed. Temperature of synthesized particles and main particles by surface modification-
When evaluated by a viscoelasticity test, as shown in FIG. 5, the synthesized irregular-shaped particles exhibited sharp melting properties almost the same as the main particles, and both curves overlapped at 130 ° C. or higher.

The results indicate not only the structure but also the continuity of viscoelasticity. From this, the obtained particles are expected to exhibit not only mechanical strength and crush resistance but also low-temperature fixability similar to that of the main particles. In addition, the number of polymers on the surface of the main particles is sufficiently large that the outline on the outer peripheral side of the polymer does not intersect with the outer periphery of the main particles, and it can be expected that the sticking resistance is excellent. Fixing properties, mechanical strength, crush resistance, and adhesion resistance tests were performed, and all of the results were as expected and good.

Example 2-2 Cationic Dispersant (Structural Formula CH ₂ ＣＲCR ₁ COO (C
Instead of H ₂ ) _n -NHR ₂ R ₃ ), the polar group is anionic but the hydrophobic group is CH ₂ （(C) as a dispersant 2 having a styrene polymer derivative structure having the same skeleton as the polymerizable monomer.
H ₂ ) _n -CH- ◎ -COONH ₄ , except that the volume average particle size was 8.1 in the same manner as in Example 2-1.
μm particles were obtained.

In FIG. 2B, since the main particles rise from pH 5 to positive, the appropriate pH becomes about 3 to 6, and polymerization was performed by adjusting the pH to 5 with aqueous ammonia. Surface condition S
Observation by EM showed that the polymer on the surface of the main particles was slightly larger than that of Example 2-1.
As shown in (a), particles were obtained in which fine particles were uniformly coated, and no single polymer was observed. As a result of TEM observation, the fine polymer on the surface was more often rounded triangular pyramid than in Example 1-1, and a clear triangular pyramid to spherical polymer was observed. In addition, no interface with the main particles was observed.

A temperature-viscoelasticity test was performed on the synthesized surface-modified deformed particles and the main particles to evaluate the results. As shown in FIG. 5, the synthesized deformed particles showed a sharp melting point almost the same as the main particles. The two curves overlapped at 130 ° C. or higher. These results indicated not only the structure but also the viscoelastic continuity. From this, it is expected that the obtained particles exhibit not only mechanical strength and crush resistance but also low-temperature fixability similar to that of the main particles. In addition, the number of polymers on the surface of the main particles is sufficiently large that the outline on the outer peripheral side of the polymer does not intersect with the outer periphery of the main particles, and it can be expected that the sticking resistance is excellent. Fixing properties, mechanical strength and crush resistance,
When a sticking resistance test was performed, the same as in Example 2-1,
The results were good.

Comparative Example 2-1 In Example 2-1 the following fine particles were externally added to the main particles to obtain dry surface-modified particles.

Synthesis of Polystyrene Acrylate Fine Particles Styrene 0.16 parts by weight n-butyl acrylate 0.04 parts by weight Ammonium persulfate 0.006 parts by weight Ion-exchanged water 200 parts by weight Ion-exchanged water was adjusted to pH 9.8 with ammonia water. Next, this was transferred to a 2 liter four-necked flask, styrene and n-butyl acrylate were added, ammonium persulfate was further added, the temperature was set to 70 ° C. while stirring at 200 rpm, and polymerization was carried out for 8 hours. Was. The obtained particles had a volume average particle size of 0.3 μm.

The polystyrene acrylate fine particles
1 part by weight was added to 1 part by weight of the main particles of Example 2-1 and a hybridizer system (HYBRIDIZER NH) was added.
(S-0, manufactured by NARAKIKAI) at 1200 rpm for 10 minutes to obtain dry surface modified particles. When the state of the surface was observed by SEM, the externally added state of the polystyrene fine particles was more nonuniform than uniform, the main particles were exposed, and the outline often intersected the main particles.

As a result of TEM observation, many of the polystyrene acrylate fine particles on the surface were embedded in the main particles, but the interface with the main particles was intermittent.
Fine particles were observed to be detached from the main particles during the preparation of the ultra-thin section of M. Therefore, in this method, it is necessary to separate and collect the non-externally added fine particles. In the test for mechanical strength and crushing resistance, the fine powder ratio was as very poor as 12%. In the sticking resistance test, sticking was observed after printing 500 sheets. In the viscoelasticity test, as shown in FIG. 5, the curves of the main particles did not overlap. From this, it was expected that the fixing temperature was increased, and in fact, the result of the fixing test was 75% and was x.

Comparative Example 2-2 In Example 2-1, the following fine particles were externally added to the main particles by a wet method to obtain surface-modified particles.

Synthesis of polystyrene acrylate fine particles Styrene 0.16 parts by weight n-butyl acrylate 0.04 parts by weight AIBN.2HC1 (isobutylamidohydrochloric acid) 0.006 parts by weight Ion-exchanged water 200 parts by weight First, ion-exchanged water Was adjusted to pH 9.8 with aqueous ammonia, and then transferred to a 2 liter four-necked flask,
Add styrene and n-butyl acrylate, and add AIBN
2H1 was added, the temperature was set to 70 ° C. while stirring at 200 rpm, and polymerization was carried out for 8 hours. The obtained particles had a volume average particle size of 0.2 μm. A dispersion of 0.05 part by weight of the positively chargeable polystyrene acrylate fine particles was added to 1 part by weight of the main particles of Example 2-1 and mixed by ultrasonic waves to adhere the fine particles to the main particles. To obtain a surface-modified particle by general wet external addition.

When the state of the surface was observed by SEM, the externally added state of the polystyrene fine particles was more non-uniform than uniform, the main particles were exposed, and the outline often intersected the main particles. As a result of TEM observation, many of the polystyrene acrylate fine particles on the surface were embedded in the main particles, but since the interface with the main particles was intermittent, the fine particles were removed from the main particles when preparing ultrathin sections of the TEM. Separation was observed. From these facts, it is expected that this method requires the separation and collection of non-externally added fine particles, and also has problems in mechanical strength, crush resistance, and sticking resistance. In the mechanical strength and crush resistance tests, the fine powder ratio was very poor at 10%. In the sticking resistance test, occurrence of sticking was observed after printing 800 sheets. In the viscoelasticity test, the curve did not overlap with the curve of the main particles, and in the fixing test, it was x at 80% as in Comparative Example 2-1.

Comparative Example 2-3 The particle size was adjusted in the same manner as in Example 2-1 except that the pH was adjusted to 10.5 with aqueous ammonia when adjusting the pH.
μm particles were obtained. The state of the surface was observed by SEM. As a result, particles whose surface was humidified in a smooth coat form as obtained by seed polymerization were obtained. When a mechanical strength and crush resistance test was performed, the fine powder ratio was 1% or less, and very good results were obtained. No sticking occurred in the sticking resistance test. However, in the viscoelasticity test, it did not overlap with the curve of the main particles, and the result of the fixing test was 65%, that is, x.

Reference Example Dispersant (Structural formula CH ₂ ＣＲCR ₁ COO (CH ₂ ) _n —N
HR ₂ R ₃₎ in place of 0.006 part by weight, the same dispersant (Formula _{CH 2 = CR 1 COO (CH} 2) n -NHR 2
R ₃ ) CH ₂ （(CH ₂ ) _n —CH as an anionic dispersant having 0.003 parts by weight and a styrene polymer derivative structure
-◎ -COONH ₄ was prepared in the same manner as in Example 2-1 except that 0.003 parts by weight of COONH ₄ was used.
5 μm particles were obtained. When the state of the surface was observed by SEM, a dendritic polymer as shown in FIG. 4B was found on the surface.

As a result of TEM observation, the polymer on the surface was elongated in a dendritic manner, but no interface with the main particles was observed as in the case of the triangular pyramid shape. It intersected the particles. The fixability test and the viscoelasticity test were good, but the mechanical strength and crushing resistance test were poor due to the length of the polymer, and the exposed portion of the main particles was large due to the small number of adhered polymers. In addition, the outline crossed the main particles, and the sticking resistance test also gave a poor result. Therefore, a toner that achieves the object of the present invention was not obtained.

The test results of the above Examples and Comparative Examples are summarized below.

Mechanical strength / crush resistance Surface condition Single fine particles / non-externally added particles Example 1-1 ○ Uniform None Example 1-2 ○ Uniform None Example 1-3 ○ Uniform None Example 1-4 ○ Uniform None Comparative example 1-1 × non-uniform Yes Comparative example 1-2 × non-uniform Yes Comparative example 1-3-Coat uniform-Comparative example 1-4-Rough unevenness-Comparative example 1-5 Not possible Not possible Not possible ... Evaluation Test cannot be performed. -: No evaluation test was performed.

Overlap of viscoelastic curves Fixing property Sticking resistance Crushing resistance Polymer shape Example 2-1 ○ ○ ○ ○ Triangular pyramid Example 2-2 ○ ○ ○ ○ Triangular pyramid to spherical Comparative example 2- 1 × × × × External addition of small particles Comparative example 2-2 × × × × External addition of small particles Comparative example 2-3 × × ○ ○ Reference example of coat form ○ ○ × × Dendritic (outer line ×)

[0094]

As described above, according to the present invention,
It is possible to deform the main particles by modifying the surface of the resin particles without causing seed polymerization, thereby obtaining deformed particles similar to the fine particle externally added structure. The surface of the main particles is uniformly modified, and irregularly shaped particles which do not require the operation of separating the unexternally added small particles are obtained. As a result, it is possible to provide irregularly shaped particles having better mechanical strength and durability than those manufactured by a general dry or wet external addition method.

Further, according to the present invention, it is possible to provide a toner having excellent mechanical strength, crushing resistance and sticking resistance without forming a shell having a high softening point. This makes it possible to provide an electrophotographic toner that satisfies both low-temperature fixability and fixation resistance by lowering the softening point of the main particles.

[Brief description of the drawings]

FIG. 1 is a flowchart of a method for deforming resin particles by surface modification according to the present invention.

FIG. 2 shows a method for obtaining a pH range in the method of the present invention.
FIG. 4 is a characteristic diagram showing a pH-zeta potential curve.

FIG. 3 is a conceptual diagram of an irregularly shaped particle according to the present invention.

FIG. 4 is an electron micrograph of the toner according to the present invention.

FIG. 5 is a characteristic diagram showing a temperature-complex viscoelastic curve of the toner according to the present invention.

FIG. 6 is a schematic sectional view of a color printer using the toner according to the present invention.

[Explanation of symbols]

301: zeta potential curve of main particle 1, 200: developing device, 201: photoreceptor, 303: pH adjustment proper region, 20
2. Charging device, 203: Laser exposure device, 204: Blade cleaning device, 205: Static elimination lamp, 209
... Transfer device, 210 ... Fixing device, 211 ... Heating roller, 212 ... Pressing roller, 213 ... Image support, 30
2 ... Zeta potential curve of dispersant 1; 304 ... Zeta potential curve of main particles 1; 305 ... Zeta potential curve of dispersant 2
06: pH adjustment appropriate region, 401: Cross section of irregular shaped particles, 40
2: Main particles, 403: Surface modified with polymerized and grown polymer, 404: Cross section of electrophotographic toner, 405: Low softening point main particles, 406: Triangular pyramidal polymer, 407: Outline line, 408 … Main particles, 409… dendritic polymer

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuka Nakamura 70, Yanagicho, Saiwai-ku, Kawasaki-shi, Kanagawa Prefecture Inside the Toshiba Yanagimachi Plant (56) References JP-A-7-258306 (JP, A) JP-A-5 -331216 (JP, A) JP-A-5-331215 (JP, A) JP-A-5-271213 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08F 2/00- 2/60

Claims (3)

(57) [Claims] In an aqueous system, in the presence of a main particle, an addition polymerizable monomer, a dispersant having a hydrophobic group having a skeleton of the addition polymerizable monomer, and a water-soluble polymerization initiator, (Zeta potential of main particles) | ≦ 20 mV, and {| (Zeta potential of dispersant) | − | (Zeta potential of main particles) |}
A method for deforming resin particles by surface modification, wherein the monomer is polymerized on the surface of the main particles in a pH range of ≧ 10 mV. 2. In an aqueous system, in the presence of a main particle, an addition polymerizable monomer, a dispersant having a hydrophobic group having a skeleton of the addition polymerizable monomer, and a water-soluble polymerization initiator, (Zeta potential of main particles) | ≦ 20 mV, and {| (Zeta potential of dispersant) | − | (Zeta potential of main particles) |}
In a pH range such that ≧ 10 mV, the surface is characterized in that the monomer is polymerized on the surface of the main particles, and the dispersant and the main particles have the same stable polarity in an aqueous solution. A method for deforming resin particles by modification. 3. In an aqueous system, in the presence of a main particle, an addition polymerizable monomer, a dispersant having a hydrophobic group having a skeleton of the addition polymerizable monomer, and a water-soluble polymerization initiator, (Zeta potential of main particles) | ≦ 20 mV, and {| (Zeta potential of dispersant) | − | (Zeta potential of main particles) |}
The modified resin particles, wherein the main particles are surface-modified by polymerizing the monomer on the surface of the main particles in a pH range of ≧ 10 mV.