JP2002108005A - Electrophotographic toner and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide toner which suppresses hot offsetting in heat fixation and can form an image of high image quality in the case of toner produced by a polymerization method and has superior fixability in the case of a small diameter toner and to provide a method for producing the toner. SOLUTION: The electrophotographic toner is obtained by polymerizing a radical polymerizable monomer composition containing a chain transfer agent selected from mercaptosilane compounds of the formula HS-R1-Si(OR2)(OR3)-R4 (where R1 is a 1-20C alkylene and R2-R4 are each a 1-4C alkyl) in an aqueous medium and subjecting the resulting resin particles to salting-out/fusion in an aqueous medium.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic toner (hereinafter, also simply referred to as "toner") and a method for producing the same.

[0002]

2. Description of the Related Art From the viewpoint of fixability, it is necessary to control the molecular weight distribution of a resin. For example, to suppress high-temperature offset, it is necessary to improve the elastic modulus at high temperatures, and it is preferable to increase the high molecular weight component.
On the other hand, in order to improve the adhesion to an image forming support such as paper, it is preferable to increase the low molecular weight component. In order to satisfy such contradictory functions with a resin, it is necessary to expand the molecular weight distribution.

On the other hand, it is desired to reduce the particle size of the toner from the viewpoint of high image quality. In recent years, a polymerization toner has been devised as a method for producing a toner having a small particle diameter. A method of preparing an irregular shaped toner by associating or salting out / fusing resin particles and colorant particles as necessary with the polymerized toner,
There is a method of dispersing a radical polymerizable monomer and a colorant, then dispersing droplets in an aqueous medium or the like so as to have a desired toner particle size, and performing suspension polymerization.

[0004] Particularly, a polymerized toner having a small particle size has a disadvantage that the toner itself has a small heat capacity, so that it tends to be in an excessively molten state, and in particular, a high-temperature offset tends to occur.

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a polymerized toner capable of suppressing a high-temperature offset during heat fixing and forming a high-quality image, and a method for producing the same. It is in. Another object of the present invention is to provide a toner having excellent fixability and a method for producing the same for a small particle size toner.

[0006]

The above object of the present invention is attained by the following constitutions.

[0007] 1. Resin particles prepared by polymerizing a radical polymerizable monomer composition containing a chain transfer agent selected from the mercaptosilane compounds represented by the general formula (1) in an aqueous medium are salted out in an aqueous medium. / An electrophotographic toner obtained by fusing.

[0008] 2. Resin particles prepared by polymerizing a radical polymerizable monomer composition containing a chain transfer agent selected from the mercaptosilane compounds represented by the general formula (1) in an aqueous medium are salted out in an aqueous medium. / A method for producing an electrophotographic toner, which is produced by fusing.

3. A composition in which a colorant is dispersed in a radical polymerizable monomer composition containing a chain transfer agent selected from the mercaptosilane compounds represented by the general formula (1) is subjected to suspension polymerization in an aqueous medium. An electrophotographic toner, which is obtained.

[0010] 4. A composition in which a colorant is dispersed in a radical polymerizable monomer composition containing a chain transfer agent selected from the mercaptosilane compounds represented by the general formula (1) is subjected to suspension polymerization in an aqueous medium. A method for producing an electrophotographic toner, characterized by being produced.

5. Aggregating resin particles and colorant particles prepared by polymerizing a radically polymerizable monomer composition containing a chain transfer agent selected from the mercaptosilane compounds represented by the general formula (1) in an aqueous medium. A toner for electrophotography, obtained by fusing secondary particles obtained by heating.

6. Aggregating resin particles and colorant particles prepared by polymerizing a radically polymerizable monomer composition containing a chain transfer agent selected from the mercaptosilane compounds represented by the general formula (1) in an aqueous medium. A method for producing an electrophotographic toner, wherein the secondary particles are produced by fusing the obtained secondary particles.

That is, as a result of intensive studies, the present inventors have found that it is necessary to improve the releasability of the toner itself, and have completed the present invention.

As a result of studying the behavior of high-temperature offset during fixing, the present inventors have found that improving the releasability of the resin itself is the most effective in solving the problem. It is generally known that increasing the elastic modulus at high temperatures is effective for improving the releasability of the resin itself.

However, by increasing the modulus of elasticity at high temperatures, the viscosity of the toner itself at the time of melting also increases,
So-called fixing property cannot be improved.

In the past, various proposals have been made in the past for providing a resin with a highly releasable unit to the resin itself, for example, a polymer using a monomer having a substituent having a fluorine or silicon element in a side chain. However, in this method, the releasability of the resin itself, that is, the adhesiveness itself is also reduced, so that although the high-temperature offset can be improved, there is a disadvantage that the fixability itself is also reduced.

Therefore, as a result of diligent studies in order to achieve both of the problems, a method for improving the releasability while maintaining the fixability of the resin itself was found. That is, by using the mercaptosilane compound of the present invention as a chain transfer agent, both can be achieved.

Although the reason for this is not clear, the fixing property is maintained in the main chain portion of the main component of the resin, and the terminal of the resin is terminated by a chain transfer agent, so that a component having releasability is used as a substituent to make the resin terminal. It is presumed that the release function was imparted by introducing the compound into the toner, and that both the fixing property and the release property could be achieved.

Hereinafter, the present invention will be described in more detail. The present invention is characterized in that the chain transfer agent represented by the general formula (1) is introduced into a resin described later.

In the general formula (1), R ₁ has 1 to ₁ carbon atoms.
20 alkylene groups, R ₂ , R ₃ and R ₄ represent an alkyl group having 1 to ₄ carbon atoms, and R ₁ preferably represents an alkylene group having 1 to 15 carbon atoms.

Specific examples of the compound represented by the general formula (1) include the following compounds.

Mercaptomethyldimethoxysilane, mercaptomethyldiethoxysilane, mercaptomethylethyldimethoxysilane, mercaptomethylethyldiethoxysilane, 2-mercaptoethyldimethoxysilane,
-Mercaptoethyldiethoxysilane, 2-mercaptoethylethyldimethoxysilane, 2-mercaptoethylethyldiethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropylmethyldiethoxysilane, 3-mercaptopropylethyldimethoxysilane, 3 -Mercaptopropylethyldiethoxysilane, 4-mercaptobutylmethyldimethoxysilane, 4-mercaptobutylmethyldiethoxysilane,
-Mercaptobutylethyldimethoxysilane, 4-mercaptobutylethyldiethoxysilane, 8-mercaptooctylethyldimethoxysilane, 8-mercaptooctylethyldiethoxysilane, 12-mercaptododecylethyldimethoxysilane, 12-mercaptododecylethyldiethoxysilane.

The amount of the toner used is from 0.01 to the total mass of the toner.
5% by mass is preferred. Next, the resin particles produced using the above compound will be described.

The resin particles (hereinafter, also simply referred to as resin)
From the viewpoint of molecular weight, at least 100,000 to 1,0
Both a high molecular weight component having a peak or shoulder in the region of 00000 and a low molecular weight component having a peak or shoulder in the region of 1,000 to less than 20,000, that is, two or more peaks, and Resin particles into which the compound represented by the formula (1) is introduced are preferred.

The method for measuring the molecular weight of a resin by GPC is described in US Pat.
It is a measurement by GPC (gel permeation chromatography) using HF as a solvent. That is, the measurement sample is 0.5 to 5 mg, more specifically, 1 mg for THF.
Is added and stirred at room temperature using a magnetic stirrer or the like to dissolve sufficiently. Then, after treating with a membrane filter having a pore size of 0.45 to 0.50 μm, the mixture is injected into GPC. The GPC measurement conditions were as follows: stabilize the column at 40 ° C., and set the THF to 1 m / min.
at a flow rate of 1 l / l and a sample at a concentration of 1 mg / ml
Inject μl and measure. The column is preferably used in combination with a commercially available polystyrene gel column.

For example, Shodex G manufactured by Showa Denko KK
PC KF-801,802,803,804,80
5,806,807 and TSKg manufactured by Tosoh Corporation
elG1000H, G2000H, G3000H, G4
000H, G5000H, G6000H, G7000
H, a combination of TSK guard columns, and the like.

As a detector, a refractive index detector (I
R detector) or a UV detector may be used. In measuring the molecular weight of a sample, the molecular weight distribution of the sample is calculated using a calibration curve created using monodispersed polystyrene standard particles. It is preferable to use about 10 polystyrenes for preparing a calibration curve.

In the present invention, a release agent may be used in combination, and the release agent itself is not particularly limited. Low molecular weight polyolefin wax such as polypropylene and polyethylene, paraffin wax, Fischer-Tropsch wax, ester wax and the like can be used. Preferred is an ester wax represented by the following general formula.

R _1- (OCO-R ₂ ) _{n wherein} n is an integer of 1-4, preferably 2-4, more preferably 3-4, particularly preferably 4, R ₁ and R ₂ are substituted Shows a hydrocarbon group which may have a group. R ₁ has 1 to ₁ carbon atoms
40, preferably 1-20, more preferably 2-5,
R ₂ is from 1 to 40 carbon atoms, preferably 16 to 30, more preferably listed below specific examples of a a] ester wax 18-26, but the invention is not limited thereto.

[0030]

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[0031]

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The addition amount is preferably from 1 to 30% by mass, more preferably from 2 to 20% by mass, and still more preferably from 3 to 15% by mass, based on the total mass of the toner.

In the present invention, the term “salting out / fusing” refers to salting out resin particles produced in the polymerization step with a coagulant,
This refers to heating and fusing at the same time as removing excess dispersant and surface activity.

The toner of the present invention is obtained by dissolving a releasing agent in a monomer, dispersing the releasing agent in water, and polymerizing the resin to form resin particles containing the ester compound in the resin particles. In both cases, it is preferable to form a toner by salting out / fusing.

The method for producing the toner of the present invention will be described. The toner of the present invention is prepared by suspension polymerization or emulsion polymerization of a monomer in a liquid to which an emulsion of necessary additives is added to produce fine polymerized particles, and thereafter, an organic solvent and a coagulant. Can be produced by a method of adding and the like. A method of preparing by mixing and associating with a dispersion liquid such as a release agent or a colorant necessary for the composition of the toner at the time of association, or dispersing a toner component such as a release agent or a colorant in a monomer. And then emulsion polymerization. Here, the association means that a plurality of resin particles and colorant particles are fused.

The aqueous medium of the present invention means a medium containing 50% by mass or more of water. That is, various constituent materials such as a colorant and a release agent, if necessary, a charge control agent, and a polymerization initiator are added to the polymerizable monomer, and the homogenizer, a sand mill, a sand grinder, an ultrasonic disperser, or the like is used. Various constituent materials are dissolved or dispersed in the polymerizable monomer. The polymerizable monomer in which these various constituent materials are dissolved or dispersed is dispersed in an aqueous medium containing a dispersion stabilizer into oil droplets of a desired size as a toner using a homomixer, a homogenizer, or the like. Thereafter, the stirring mechanism is moved to a reaction device, which is a stirring blade described later, and heated to cause the polymerization reaction to proceed. After completion of the reaction, the toner of the present invention is prepared by removing the dispersion stabilizer, filtering, washing and drying.

Further, as a method of producing the toner of the present invention, a method of preparing by associating or fusing resin particles in an aqueous medium can also be mentioned. This method is not particularly limited.
Nos. 5252, 6-329947 and 9-1.
The method disclosed in Japanese Patent No. 5904 can be exemplified.

That is, a method of associating a plurality of resin particles and dispersed particles of a constituent material such as a colorant, or a plurality of fine particles having a resin and a colorant, etc., in particular, dispersing these in water using an emulsifier, followed by critical aggregation At the same time as adding a coagulant over the concentration and salting out, the formed polymer itself is heated and fused at the glass transition temperature or higher to gradually grow the particle size while forming fused particles. When it becomes, a large amount of water is added to stop the particle size growth, and further heating,
The toner of the present invention can be formed by smoothing the surface of the particles while stirring, controlling the shape of the particles, and heating and drying the particles in a fluid state while keeping the particles wet. Here, an organic solvent that is infinitely soluble in water may be added together with the coagulant.

As the polymerizable monomer constituting the resin, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-chlorostyrene, 3,4- Dichlorostyrene,
p-phenylstyrene, p-ethylstyrene, 2,4-
Dimethylstyrene, p-tert-butylstyrene, p
-N-hexylstyrene, pn-octylstyrene,
pn-nonylstyrene, pn-decylstyrene, p
Styrene or a styrene derivative such as -n-dodecylstyrene, methyl methacrylate, ethyl methacrylate,
N-butyl methacrylate, isopropyl methacrylate,
Methacrylate derivatives such as isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, and dimethylaminoethyl methacrylate. , Methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate,
Acrylic ester derivatives such as n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, phenyl acrylate, and the like, olefins such as ethylene, propylene, and isobutylene, vinyl chloride, vinylidene chloride, and vinyl bromide , Vinyl fluoride such as vinyl fluoride and vinylidene fluoride; vinyl esters such as vinyl propionate, vinyl acetate and vinyl benzoate; vinyl ethers such as vinyl methyl ether and vinyl ethyl ether; vinyl methyl ketone and vinyl ethyl ketone , Vinyl ketones such as vinyl hexyl ketone, N-vinyl compounds such as N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone, vinyl compounds such as vinyl naphthalene and vinyl pyridine, acrylonitrile, Acrylonitrile, there are acrylic acid or methacrylic acid derivatives such as acrylamide. These vinyl monomers can be used alone or in combination.

Further, it is more preferable to use a polymerizable monomer constituting the resin in combination with one having an ionic dissociation group. For example, those having a substituent such as a carboxyl group, a sulfonic acid group or a phosphoric acid group as a constituent group of a monomer, specifically, acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, and fumaric acid. Acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester, styrene sulfonic acid, allyl sulfosuccinic acid,
2-acrylamido-2-methylpropanesulfonic acid,
Acid phosphooxyethyl methacrylate, 3-chloro-2-acid phosphooxypropyl methacrylate, and the like.

Further, divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate,
Polyfunctional vinyls such as neopentyl glycol diacrylate can be used to form a crosslinked resin.

These polymerizable monomers can be polymerized using a radical polymerization initiator. In this case, an oil-soluble polymerization initiator can be used in the suspension polymerization method. As the oil-soluble polymerization initiator, 2,2'-azobis- (2,4
-Dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis (cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvalero Azo or diazo polymerization initiators such as nitrile and azobisisobutyronitrile, benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide , Dicumyl peroxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, 2,2-bis-
Examples thereof include peroxide-based polymerization initiators such as (4,4-t-butylperoxycyclohexyl) propane and tris- (t-butylperoxy) triazine, and polymer initiators having a peroxide in a side chain. .

When the emulsion polymerization method is used, a water-soluble radical polymerization initiator can be used. Examples of the water-soluble polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate, azobisaminodipropane acetate, azobiscyanovaleric acid and salts thereof, and hydrogen peroxide.

Examples of the dispersion stabilizer include tricalcium phosphate, magnesium phosphate, zinc phosphate, aluminum phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, and calcium sulfate. , Barium sulfate,
Bentonite, silica, alumina and the like can be mentioned. Further, a surfactant generally used as a surfactant such as polyvinyl alcohol, gelatin, methyl cellulose, sodium dodecylbenzenesulfonate, ethylene oxide adduct, and higher alcohol sodium sulfate can be used as a dispersion stabilizer.

The above-mentioned resin particles excellent in the present invention include:
Those having a glass transition point of 20 to 90 ° C are preferred, and those having a softening point of 80 to 220 ° C are preferred. The glass transition point is measured by a differential calorimetric analysis method, and the softening point can be measured by a Koka flow tester. Further, these resins have a number average molecular weight (Mn) of 1,000 to 100,000 and a weight average molecular weight (Mw) of 2 as measured by gel permeation chromatography.
000-1,000,000 are preferred. Further, as the molecular weight distribution, those having Mw / Mn of 1.5 to 100, particularly 1.8 to 70 are preferable.

The coagulant used is not particularly limited, but those selected from metal salts are preferably used. Specifically, as a monovalent metal, for example, a salt of an alkali metal such as sodium, potassium, and lithium, and as a divalent metal, for example, a salt of an alkaline earth metal such as calcium and magnesium, or a divalent metal such as manganese or copper And salts of trivalent metals such as iron and aluminum. Specific examples of the salts include sodium chloride, potassium chloride, lithium chloride, calcium chloride, zinc chloride, copper sulfate, magnesium sulfate, and manganese sulfate. Can be mentioned. These may be used in combination.

It is preferable that these coagulants are added at a concentration higher than the critical coagulation concentration. The critical aggregation concentration is an index relating to the stability of the aqueous dispersion, and indicates the concentration at which aggregation occurs when a coagulant is added. This critical aggregation concentration is
It varies greatly depending on the emulsified component and the dispersant itself. For example, Seizo Okamura et al.
7, 601 (1960), edited by The Society of Polymer Science, Japan, and the like, and a detailed critical aggregation concentration can be determined.
As another method, a desired salt is added to the target particle dispersion at a different concentration, the 、 (zeta) potential of the dispersion is measured, and the salt concentration at which this value changes is defined as the critical aggregation concentration. You can also ask.

The amount of the coagulant preferably used in the present invention may be at least the critical coagulation concentration, but is preferably at least 1.2 times the critical coagulation concentration, more preferably at least 1.5 times the critical coagulation concentration.
It is better to add it twice or more.

The infinitely soluble solvent means a solvent that is infinitely soluble in water, and in the present invention, a solvent that does not dissolve the formed resin is selected.

Specific examples include alcohols such as methanol, ethanol, propanol, isopropanol, t-butanol, methoxyethanol and butoxyethanol, nitriles such as acetonitrile, and ethers such as dioxane. Particularly, ethanol, propanol and isopropanol are preferred.

The addition amount of the infinitely soluble solvent is preferably 1 to 100% by volume based on the polymer-containing dispersion to which the flocculant has been added.

In order to make the shape uniform, it is preferable to prepare a colored particle, filter it, and then fluidly dry a slurry containing 10% by mass or more of water based on the particle. Those having a polar group in the polymer are preferred. It is considered that the reason for this is that the existing water exerts an effect of slightly swelling the polymer in which the polar group is present, so that it is particularly easy to make the shape uniform.

The toner of the present invention contains a resin and a colorant. If necessary, the toner of the present invention may contain a releasing agent or a charge control agent as a fixability improving agent. Further, an external additive composed of inorganic fine particles, organic fine particles, and the like may be added to the toner particles containing the resin and the colorant as main components.

As the colorant used in the toner of the present invention, any of carbon black, magnetic substance, dye, pigment and the like can be used arbitrarily. As the carbon black, channel black, furnace black, acetylene black,
Thermal black, lamp black and the like are used. Ferromagnetic metals such as iron, nickel, and cobalt as magnetic materials,
Alloys containing these metals, compounds of ferromagnetic metals such as ferrite and magnetite, alloys that do not contain ferromagnetic metals but show ferromagnetism by heat treatment, such as manganese-copper-
An alloy of a type called a Heusler alloy such as aluminum, manganese-copper-tin, chromium dioxide, or the like can be used.

As the dye, C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 1
22, C.I. I. Solvent Yellow 19, 44, 7
7, 79, 81, 82, 93, 98, 10
3, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93, 9
5 and the like, and mixtures thereof can also be used.

As the pigment, C.I. I. Pigment Red 5, 48: 1, 53: 1, 57: 1, 122,
139, 144, 149, 166, 177,
178, 222, C.I. I. Pigment Orange 3
1, 43, C.I. I. Pigment Yellow 14, 1
7, 93, 94, 138, 156, 158,
180, 185, C.I. I. Pigment Green 7,
C. I. Pigment Blue 15: 3, 60 and the like, and mixtures thereof can also be used. Although the number average primary particle size varies depending on the type, it is usually 10 to 20.
About 0 nm is preferable.

As a method of adding a colorant, a method of adding polymer particles prepared by an emulsion polymerization method at the stage of aggregating by adding an aggregating agent to color the polymer, or a method of polymerizing a monomer is used. And a method of adding a colorant, polymerizing, and forming colored particles can be used. When the colorant is added at the stage of preparing the polymer, it is preferable to use the colorant after treating the surface with a coupling agent or the like so as not to inhibit the radical polymerizability.

Further, low molecular weight polypropylene (number average molecular weight = 1500 to 9000) or low molecular weight polyethylene as a fixing property improving agent may be added.

Similarly, various charge control agents are also known.
What can be dispersed in water can also be used. Specifically, nigrosine dyes, metal salts of naphthenic acid or higher fatty acids, alkoxylated amines,
Quaternary ammonium salt compounds, azo-based metal complexes, salicylic acid metal salts or metal complexes thereof.

The particles of the charge control agent and the fixability improving agent have a number average primary particle diameter of 10 to 50 in a dispersed state.
It is preferably set to 0 nm.

The shape of the toner of the present invention has an average value (average circularity) of the shape factor represented by the following equation of 0.930 to 0.9.
980 is preferable, and more preferably 0.940 to 0.9.
75.

Shape factor = (circumferential length of circle obtained from equivalent circle diameter) / (circumferential length of particle projected image) The shape factor distribution is preferably sharp, and the standard deviation of circularity is 0.10. The following is preferred, and the CV value calculated by the following formula is preferably less than 20%, and more preferably less than 10%.

CV value = (standard deviation of circularity / average circularity) × 100 By setting the average circularity to 0.930 to 0.980, the shape of the toner can be made somewhat irregular. The efficiency of heat transfer can be improved, and the fixing property can be further improved.

That is, the fixing property can be improved by setting the average circularity to 0.980 or less. Also, 0.
By setting the average circularity to 930 or more, the degree of irregularity of the particles can be suppressed, and the friability of the particles due to stress during long-term use can be suppressed.

Further, it is preferable that the distribution of the shape coefficient is sharp, and the standard deviation of the circularity is 0.10 or less, so that a toner having a uniform shape can be obtained. Since it can be reduced, the effect of preventing the fixing device from being contaminated by improving the fixing rate and reducing the offset property is further exhibited. When the CV value is also less than 20%, a sharp shape distribution can be similarly obtained, and the effect of improving the fixing property can be more remarkably exhibited.

The method of measuring the shape factor is not limited.
The average circularity can be calculated by taking a photograph enlarged to 00 times, measuring the circularity of 500 toners using an image analyzer, and calculating the arithmetic average value. In addition, as a simple measurement method, FPIA-2
000 (manufactured by Toa Medical Electronics Co., Ltd.).

In order to control the shape, a proper process end time may be determined while monitoring the characteristics of toner particles (colored particles) whose shape is being controlled in a process such as association.

Monitoring means that a measuring device is incorporated in-line and the process conditions are controlled based on the measurement result. That is, for example, in the case of a polymerization toner formed by incorporating measurement of shape and the like in-line and associating or fusing resin particles in an aqueous medium, the shape and particle size are sequentially sampled in steps such as fusing. Is measured, and the reaction is stopped when the desired shape is obtained.

The monitoring method is not particularly limited, but a flow type particle image analyzer FPIA-
2000 (manufactured by Toa Medical Electronics Co., Ltd.) can be used. This apparatus is suitable because the shape can be monitored by performing image processing in real time while passing the sample liquid. That is, a pump or the like is used from the reaction field to constantly monitor and measure the shape and the like, and stop the reaction when the desired shape and the like are obtained.

The volume average particle diameter of the toner of the present invention is measured by a Coulter Counter TA-II or a Coulter Multisizer (manufactured by Coulter). In the present invention, a Coulter Multisizer was used, connected to an interface (manufactured by Nikkaki) for outputting a particle size distribution and a personal computer. The aperture used in the Coulter Multisizer is 1
The particle size distribution and the average particle size were calculated by measuring the volume distribution of toner having a particle size of 2 μm or more using a particle having a size of 00 μm.

The toner of the present invention preferably has a volume average particle diameter of 3 to 8 μm. This particle size is
In the case where toner particles are formed by a polymerization method, the concentration can be controlled by the concentration of the coagulant, the amount of the organic solvent added, the fusing time, and the composition of the polymer itself.

When the volume average particle diameter is 3 to 8 μm, in the fixing step, the number of toner particles having a large adhesive force which flies and adheres to the heating member to cause offset is reduced, and the transfer efficiency is increased. The halftone image quality is improved, and the image quality of fine lines and dots is improved.

Further, in the toner of the present invention, more effects can be exhibited by adding and using fine particles such as inorganic fine particles and organic fine particles as external additives. The reason for this is presumed that the embedding and detachment of the external additive can be effectively suppressed, so that the effect is remarkable.

As the inorganic fine particles, it is preferable to use inorganic oxide particles such as silica, titania and alumina. Further, it is preferable that these inorganic fine particles have been subjected to a hydrophobic treatment with a silane coupling agent, a titanium coupling agent or the like. preferable. The degree of the hydrophobizing treatment is not particularly limited, but a methanol wettability of 40 to 95 is preferable. Methanol wettability is to evaluate the wettability to methanol. In this method, an inorganic fine particle to be measured is added to 50 ml of distilled water placed in a beaker having a capacity of 200 ml.
Weigh 2 g and add. Methanol is slowly dropped from a burette whose tip is immersed in the liquid until the whole of the inorganic fine particles is wet with stirring slowly. When the amount of methanol required to completely wet the inorganic fine particles is a (ml), the degree of hydrophobicity is calculated by the following equation.

Degree of hydrophobicity = (a / a + 50) × 100 The amount of the external additive to be added is 0.1 to 5.
0 mass%, preferably 0.5 to 4.0 mass%. Various external additives may be used in combination.

The toner of the present invention may be used as a one-component magnetic toner containing a magnetic material, for example, when used as a two-component developer by being mixed with a carrier, or when a non-magnetic toner is used alone. Any of them can be suitably used, but in the present invention, it is preferable to use as a two-component developer to be used by mixing with a carrier.

As the carrier constituting the two-component developer, conventionally known materials such as metals such as iron, ferrite and magnetite and alloys of these metals with metals such as aluminum and lead are used as the magnetic particles. be able to.
Particularly, ferrite particles are preferable. The magnetic particles preferably have a volume average particle size of 15 to 100 μm, more preferably 25 to 60 μm. The volume average particle diameter of the carrier can be typically measured by a laser diffraction type particle size distribution analyzer “HELOS” (manufactured by SYMPATEC) equipped with a wet disperser.

The carrier is preferably a carrier further coated with a resin or a so-called resin-dispersed carrier in which magnetic particles are dispersed in a resin. Although there is no particular limitation on the resin composition for coating, for example, an olefin resin, a styrene resin, a styrene / acrylic resin, a silicone resin, an ester resin, a fluorine-containing polymer resin, or the like is used.

The resin for constituting the resin-dispersed carrier is not particularly limited, and known resins can be used. For example, styrene acrylic resin, polyester resin, fluorine resin, phenol resin and the like can be used. can do.

As a fixing method preferably used in the present invention, a so-called contact heating method can be used. In particular, examples of the contact heating method include a heat and pressure fixing method, a heat roll fixing method, and a pressure contact heat fixing method in which fixing is performed by a rotating pressing member including a fixedly disposed heating element.

In the hot roll fixing system, a heat source is often provided inside a metal cylinder made of iron, aluminum, or the like whose surface is coated with tetrafluoroethylene or polytetrafluoroethylene-perfluoroalkoxyvinyl ether copolymer or the like. It is made up of an upper roll and a lower roll made of silicone rubber or the like. As a heat source, it has a linear heater and adjusts the surface temperature of the upper roll to 12
Heating to about 0 to 200 ° C. is a typical example. In the fixing section, pressure is applied between the upper roll and the lower roll to deform the lower roll and form a so-called nip.

The nip width is usually 1 to 10 mm, preferably 1.5 to 7 mm. Fixing linear speed is 40mm / s
ec to 600 mm / sec is preferable. When the nip is narrow, heat cannot be uniformly applied to the toner, causing uneven fixing. On the other hand, if the nip width is wide, the melting of the resin is promoted, and a problem occurs in that the fixing offset becomes excessive.

A fixing cleaning mechanism may be provided for use. As this method, a method of supplying silicone oil to a roll or a film after fixing, or a method of cleaning with a pad, roll, web or the like impregnated with silicone oil can be used.

A roll fixing device using the above fixing method may be used with a cleaning mechanism.
As a cleaning method, a method of supplying various silicone oils to the fixing film or a method of cleaning with a pad, a roll, a web, or the like impregnated with various silicone oils is used.

As the silicone oil, polydimethylsiloxane, polymethylphenylsiloxane, polydiphenylsiloxane and the like can be used. Further, a siloxane containing fluorine can also be suitably used.

FIG. 1 shows an example of a hot roll fixing device used in the present invention using the above-described fixing method.

[0087]

EXAMPLES The present invention will now be described specifically with reference to examples, but the embodiments of the present invention are not limited thereto.

(Latex Preparation Example 1) 7.08 g of an anionic activator (sodium dodecylbenzenesulfonate: SDS) was previously ion-exchanged into a 5000 ml separable flask equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introducing device. A solution dissolved in water (2760 g) is added. While stirring at a stirring speed of 230 rpm under a nitrogen stream,
The internal temperature was raised to 80 ° C. On the other hand, exemplified compound (20)
72.0 g was added to a monomer composed of 115.1 g of styrene, 42.0 g of n-butyl acrylate, and 10.9 g of methacrylic acid, and the mixture was heated to 80 ° C. and dissolved to prepare a monomer solution.

Here, the above-mentioned heated solution was mixed and dispersed by a mechanical disperser having a circulation path to produce emulsified particles having a uniform dispersed particle diameter. Next, 0.84 g of a polymerization initiator (potassium persulfate: KPS) was added to 200 parts of ion-exchanged water.
g), and the mixture was heated and stirred at 80 ° C. for 3 hours to produce latex particles. Subsequently, 7.73 g of a polymerization initiator (KPS) was further added to ion-exchanged water 24.
A solution dissolved in 0 ml was added, and 15 minutes later, 383.6 g of styrene and n-butyl acrylate 14 were added at 80 ° C.
0.0 g, 36.4 g of methacrylic acid, and 14.0 g of 3-mercaptopropylmethyldiethoxysilane
It was dropped over 20 minutes. After completion of the dropwise addition, the mixture was heated and stirred for 60 minutes and then cooled to 40 ° C. to obtain latex particles. This latex particle is referred to as Latex 1.

(Preparation Example 2 of Latex) In Preparation Example 1 of Latex, 15.0 g of 4-mercaptobutylmethyldimethoxysilane was used in place of 3-mercaptopropylmethyldiethoxysilane, and (19) was used in place of Exemplified Compound (20). ) Was used in the same manner except that 120.0 g of) was used to obtain latex particles. This is designated as latex 2.

(Latex Preparation Example 3) Latex particles were obtained in the same manner as in Latex Preparation Example 1, except that 15.0 g of 4-mercaptobutylmethyldiethoxysilane was used instead of 3-mercaptopropylmethyldiethoxysilane. . This is designated as Latex 3.

(Latex Preparation Example 4) Latex particles were obtained in the same manner as in Latex Preparation Example 1, except that 20.0 g of 8-mercaptooctylethyldimethoxysilane was used instead of 3-mercaptopropylmethyldiethoxysilane. This is designated as Latex 4.

(Latex Preparation Example 5) In latex preparation example 1, t-dodecyl mercaptan was used in place of 3-mercaptopropylmethyldiethoxysilane for 15.0.
Latex particles were obtained in the same manner except that g was used. This is designated as Latex 5.

(Example of Toner Preparation) Production of Colored Particles 9.2 g of sodium n-dodecyl sulfate is dissolved in 160 ml of ion-exchanged water with stirring. 20 g of Regal 330R (carbon black manufactured by Cabot Corporation) is added to this solution with stirring.
Was gradually added, and then dispersed using CLEARMIX. Otsuka Electronics ELS-80 Electrophoretic Light Scattering Photometer
As a result of measuring the particle size of the dispersion using 0, the mass average diameter was 112 nm. This dispersion is referred to as “colorant dispersion 1”.

1250 g of the above-mentioned “latex 1”, 2000 ml of ion-exchanged water and “colorant dispersion 1” were equipped with a temperature sensor, a cooling pipe, a nitrogen introducing device, and a stirring device.
Stir into a 4 liter four-necked flask. After adjusting to 30 ° C., a 5 mol / L aqueous sodium hydroxide solution was added to the solution to adjust the pH to 10.0. Then, 52.6 g of magnesium chloride hexahydrate was added to deionized water 72.
The aqueous solution dissolved in ml was added under stirring at 30 ° C. for 10 minutes. Thereafter, after standing for 3 minutes, heating is started and the temperature is raised to 90 ° C. in 6 minutes (heating rate = 10 ° C.).
° C / min). In that state, the particle size is measured using a coulter counter TA.
When measured by II, when the volume average particle diameter became 6.5 μm, an aqueous solution in which 115 g of sodium chloride was dissolved in 700 ml of ion-exchanged water was added to stop the particle growth, and the liquid temperature was further continued at 90 ° C. ± 2. The mixture was heated and stirred at 6 ° C. for 6 hours to cause salting out / fusion. Thereafter, 30 ° C. under the condition of 6 ° C./min.
Then, hydrochloric acid was added to adjust the pH to 2.0, and the stirring was stopped. The resulting colored particles are filtered, washed repeatedly with ion-exchanged water, and then dried with warm air at 40 ° C.
Colored particles were obtained. The colored particles obtained as described above are referred to as “colored particles 1”.

[0096] In the same manner as in "Colored particles 1Bk" to "Latex 2" to "Latex 5" except that carbon black and a colorant shown below were used.
“Colored particles 5C” were obtained.

[0097]

[Table 1]

(Production Example 6Bk of Colored Particles): Example of Suspension Polymerization In a four-necked flask equipped with a high-speed stirrer (TK homomixer), 710 parts by mass of ion-exchanged water and 0.1 mol / l of trisodium phosphate were added. Add 450 parts by mass of aqueous solution, and add
C. and 68 parts by mass of a 1.0 mol / l aqueous solution of calcium chloride was gradually added under stirring conditions at a rotation speed of 12000 rpm to prepare an aqueous dispersion medium containing a dispersion containing colloidal tricalcium phosphate. Then, 165 parts by mass of a styrene monomer and 35 parts by mass of n-butyl acrylate, 14 parts by mass of carbon black (Legal 330R) were added, and 30 parts by mass of an ester wax (19) was added to a dispersion liquid dispersed by a sand grinder. Dissolved. Then, 2,2'-mer was used as a polymerization initiator with 2 parts by mass of 3-mercaptopropylmethyldiethoxysilane.
A solution obtained by adding 10 parts by mass of azobis (2,4-dimethylvaleronitrile) was added to the aqueous dispersion medium at a rotational speed of 1200.
Under a stirring condition of 0 rpm, the solution was gradually added to disperse the monomer-containing solution in water. Then, using a reactor having a stirring blade, a polymerization reaction was carried out for 10 hours under a nitrogen stream at 65 ° C. and 200 rpm with stirring. At the end of the polymerization reaction, hydrochloric acid was added to remove tricalcium phosphate as a dispersion stabilizer, followed by filtration, washing and drying to prepare colored particles. This is referred to as “colored particles 6Bk”. In addition, by monitoring during the polymerization, controlling the liquid temperature, the number of rotations of the stirring, and the heating time, the variation coefficient of the shape and the shape coefficient is controlled, and further, the classification coefficient in the liquid, the variation coefficient of the particle size and the particle size distribution Was arbitrarily adjusted.

(Production Example of Colored Particles 7Bk): Example of a Suspension Polymerization Example of Production of Colored Particles 6Bk, except that 3 parts by mass of 4-mercaptobutylmethyldimethoxysilane was used instead of 3-mercaptopropylmethyldiethoxysilane. Similarly, colored particles were obtained. This is referred to as colored particles 7Bk.

(Production Example 8Bk of Colored Particles): Example of Suspension Polymerization In Production Example 6Bk of Colored Particles, 3 parts by mass of 4-mercaptobutylmethyldiethoxysilane was used instead of 3-mercaptopropylmethyldiethoxysilane. In the same manner, colored particles were obtained. This is referred to as colored particles 8Bk.

(Production Example of Colored Particles 9Bk): Example of Suspension Polymerization Method was the same as in Production Example 6 of Colored Particles except that 8-mercaptooctylethyldimethoxysilane was used instead of 3-mercaptopropylmethyldiethoxysilane. Colored particles were obtained. This is referred to as colored particles 9Bk.

(Production Example of Colored Particles 10Bk): Example of Suspension Polymerization Colored particles were produced in the same manner as in Production Example 6 of Colored Particles except that t-dodecylmercaptan was used instead of 3-mercaptopropylmethyldiethoxysilane. Obtained. This is referred to as colored particles 10Bk.

* The following circularity was measured using FPIA-2000, sample analysis amount = 0.3 µm liter, number of detected particles = 1
It was measured under the condition of 500 to 5000 pieces.

* Also, the following colored particles 5Bk / Y / M / C
And the colored particles 10Bk are comparative examples.

[0105]

[Table 2]

[0106]

[Table 3]

Then, the above “colored particles 1Bk / 1Y / 1M
/ 1C "to" colored particles 5Bk / 5Y / 50M / 5C "
(Colored particle groups 1 to 5), 1% by mass of hydrophobic silica (number average primary particle diameter = 12 nm, degree of hydrophobicity = 68) and hydrophobic titanium oxide (colored particles 6Bk) to “Colored particles 10Bk”, respectively. Number average primary particle size = 20 nm, hydrophobicity =
63) and mixed with a Henschel mixer to obtain a toner. These are referred to as “toner 1Bk / 1Y / 1M / 1
C "to" toner 5Bk / 5Y / 5M / 5C ", and" toner 6Bk "to" toner 10Bk ".

Note that there is no difference between the colored particles and the toner in physical properties such as shape and particle diameter.

A ferrite carrier coated with a silicone resin and having a volume average particle diameter of 60 μm was mixed with each of the above toners to prepare a developer having a toner concentration of 6%. These are applied to the respective toners in the developer 1Bk / 1Y / 1M /
1C to developer 5Bk / 5Y / 5M / 5C (developer 1 group to
(Developer 5 group), developer 6Bk to developer 10Bk (developer 6 to developer 10).

The developer prepared here was used, and using a color copier Konica 3015, the configuration of the fixing device was changed to the configuration shown below, and a real-photo evaluation was performed.

As a fixing method, the above-described hot roll fixing device shown in FIG. 1 was used. The specific configuration is as follows.

The surface was treated with PFA (tetrafluoroethylene-
A heating roll (upper roll) made of a 1.0 mm-thick aluminum alloy covered with a tube of perfluoroalkyl vinyl ether copolymer (thickness: 120 μm) and having a diameter of 40 mm and an overall width of 310 mm and a heater built in the center. And a pressure roll (lower roll) having a 2.0 mm-thick iron cored bar having an inner diameter of 40 mm and a surface similarly formed of sponge-like silicone rubber (Asker C hardness = 48: thickness 2 mm). ing. Nip width is 5.8mm
And Using this fixing device, the printing linear velocity is set to 250
mm / sec.

As a cleaning mechanism of the fixing device, polydiphenyl silicone (having a viscosity of 10 Pa ·
s) was used.

The fixing temperature was controlled by the surface temperature of the upper roll, and was set to 175 ° C. The amount of silicone oil applied was 0.6 mg / A4 size.

[Evaluation of Characteristics] The evaluation of the fixing property was made according to Y / M / C
An A4 size halftone image (image density is 1.0 with relative reflection density when the density of the paper is "0") was printed, and the fixing ratio was measured. . The fixing rate is a value obtained by rubbing a fixed image with a 1 kg weight of “rolled cloth” and calculating a percentage change in image density before and after the rubbing.

Fixing ratio (%) = (image density after rubbing / image density before rubbing) × 100 The surface temperature of the heating roll was 175 ° C. as a center value.

The evaluation of the offset property was performed as follows. The configuration of the fixing device was the same as that described above, but the cleaning mechanism of the fixing device was not mounted, and no silicone oil was supplied. Further, the temperature of the heating roll of the fixing device can be varied. In this state, an unfixed image in which a solid black band having a width of 10 mm is printed at a position 5 mm from the leading end of A4 size vertical paper (55 kg paper / neutral paper) using only black toner as a developer, The temperature of the fixing device was raised from 150 ° C. to 240 ° C. in steps of 5 ° C., and the above-mentioned image was fixed, and the presence or absence of occurrence of offset was evaluated. In the evaluation, an offset was present in a state where the solid black image at the leading end became identifiable on A4 size paper according to the pitch of the heating roll, and the temperature was recorded as the offset occurrence temperature. The results are shown below.

[0118]

[Table 4]

[0119]

As demonstrated in the examples, the toner according to the present invention and the method for producing the same can suppress a high-temperature offset at the time of heat fixing in a polymerized toner, and can form a high-quality image. The toner having a small particle diameter has an excellent fixing property.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of a hot roll fixing device used in the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 heating roll 2 pressure roll 3 silicon oil impregnated web 4 PFA tube 5 core metal (aluminum) 6 temperature sensor 7 heater 8 sponge-like silicone rubber (elastic layer) 9 core metal (iron) 10 nip 11 toner after fixing 12 fixing Previous toner 13 Transfer material

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Kenji Hayashi 1st Konica Corporation, Sakuracho, Hino-shi, Tokyo In-house (72) Mikio Kamiyama 1st Konica Corporation, Sakuracho, Hino-shi, Tokyo F-term (reference) 2H005 AA15 AB06 CA02 CA04

Claims (6)

[Claims] 1. A resin particle prepared by polymerizing a radically polymerizable monomer composition containing a chain transfer agent selected from a mercaptosilane compound represented by the following general formula (1) in an aqueous medium is used as an aqueous resin. An electrophotographic toner obtained by salting out / fusing in a medium. General formula (1) HS-R ₁ -Si (OR ₂ ) (OR ₃ ) -R _{4 wherein} R ₁ is an alkylene group having 1 to 20 carbon atoms, R ₂ , R
₃ and R ₄ represent an alkyl group having 1 to ₄ carbon atoms. ] 2. A resin particle prepared by polymerizing a radically polymerizable monomer composition containing a chain transfer agent selected from the mercaptosilane compounds represented by the general formula (1) in an aqueous medium is used as an aqueous resin. A method for producing an electrophotographic toner, which is produced by salting out / fusing in a medium. 3. A composition prepared by dispersing a colorant in a radical polymerizable monomer composition containing a chain transfer agent selected from the mercaptosilane compounds represented by the general formula (1) in an aqueous medium. An electrophotographic toner obtained by suspension polymerization. 4. A composition prepared by dispersing a colorant in a radical polymerizable monomer composition containing a chain transfer agent selected from the mercaptosilane compounds represented by the general formula (1) in an aqueous medium. A method for producing an electrophotographic toner, which is produced by suspension polymerization. 5. A resin particle prepared by polymerizing a radically polymerizable monomer composition containing a chain transfer agent selected from the mercaptosilane compounds represented by the general formula (1) in an aqueous medium, and coloring. An electrophotographic toner obtained by fusing secondary particles obtained by aggregating agent particles. 6. A resin particle prepared by polymerizing a radically polymerizable monomer composition containing a chain transfer agent selected from the mercaptosilane compounds represented by the general formula (1) in an aqueous medium, and coloring. A method for producing a toner for electrophotography, wherein the production is performed by fusing secondary particles obtained by aggregating agent particles.