JP2000347444A - Toner for electrostatic charge image developing and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spherical toner for electrostatic charge image developing narrow in particle diameter distribution. SOLUTION: This toner has a residual solvent amount of 1-500 ppm and a GSD value of 1-1.6 and a sphericity degree of 100-130 and a rope-formed particle content of 0-5 number % and a BET specific surface area of 0.5-3 m2/g. The method for manufacturing this toner comprises a process for dissolving or dispersing a binder resin and a colorant and a process for dispersing and suspending the obtained mixed liquid composition into an aqueous medium containing fine hydrophilic inorganic particles subjected to surface treatment and a process for removing the solvent from the obtained liquid suspension, and further, an ionic substance is added into the liquid suspension between the dispersing and suspending process and the process for removing the solvent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner for developing an electrostatic image containing a binder resin and a colorant, which is used in an electrophotographic method or an electrostatic recording method, and a method for producing the same.

[0002]

2. Description of the Related Art Several methods for producing fine polymer particles used in an electrostatic image developing toner for developing an electrostatic latent image formed by electrophotography or electrostatic recording have been known. Have been. Among them, there is a method for producing polymer fine particles directly by polymerizing a monomer as a starting material by a polymerization reaction such as a suspension polymerization method, an emulsion polymerization method, a seed polymerization method or a dispersion polymerization method. However, in these polymerization methods, it is difficult to remove residual monomers and surfactants, it is difficult to internally add insoluble materials such as a colorant, a charge control agent and a release agent, and the type and particle size range of the obtained polymer. Are limited, and it is necessary to examine the optimum conditions for the particle formation every time the material composition is changed.

There is also a method for producing polymer fine particles by making a polymer prepared by a polymerization reaction into fine particles in advance. Among them, the melt-kneading pulverization method is
This is a method of obtaining fine polymer particles by pulverizing a previously coarsely pulverized polymer using a fine pulverizer such as a mechanical rotary type or a jet type, and then classifying it. It is a manufacturing method. However, the polymer fine particles obtained by this method are irregular, have a nonuniform particle size, and have disadvantages such as requiring a classification step to sharpen the particle size distribution.

Further, there is a method in which a polymer solution previously dissolved in a solvent is sprayed into particles to form particles, but the polymer fine particles produced by this method are not uniform in particle size, and a large-sized manufacturing apparatus is required. There are drawbacks such as necessity. Alternatively, by adding a poor solvent to the polymer solution previously dissolved in the solvent, or by cooling the polymer solution previously dissolved by heating in the solvent,
Although there is a method of precipitating polymer fine particles, this method has drawbacks such as difficulty in controlling the shape of the particles, and difficulty in selecting the type of polymer to be used and the type of solvent for it. There is also a method of dispersing a heat-melted polymer in a medium heated to a temperature higher than its melting point, followed by cooling to obtain polymer fine particles.In this method, in most cases, the medium is aqueous. In addition, there are drawbacks such as the need for pressurization, the difficulty in cleaning when the medium is oil-based, and the difficulty in controlling the shape.

Further, a polymer solution (a mixed solution of toner materials, etc.) previously dissolved in a solvent is dispersed and suspended in an aqueous medium, and the solvent is removed by heating or reducing the pressure to form particles. Method (Japanese Patent Publication No. 38-20)
No. 95, Japanese Patent Publication No. 61-28688, Japanese Patent Application Laid-Open No. 63-25664, Japanese Patent Application Laid-Open No. 7-152202, Japanese Patent Application Laid-Open No. 915902, etc.) are known. This method has no residual monomer,
The surfactant does not need to be removed because it is not used.It is easy to add insoluble materials such as colorant, charge control agent and release agent. There are many advantages such as not being limited, it is not necessary to study the optimal conditions of particle formation even if the material composition is changed, the particle size distribution of the obtained particles is sharp, and the aqueous medium is easy to clean. Therefore, among the conventional methods, it is considered to be a method suitable for industrialization. On the other hand, as a binder resin for a toner for developing an electrostatic image used in the field of electrophotography, a polyester which is instantaneously melted at the time of fixing, makes the image surface smooth, and has sufficient flexibility even when the molecular weight is reduced. Often used. In particular, in the case of color toners, polyester resins are often used in terms of color developability and flexibility, and it has been necessary to control the shape of the toner using polyester. However, the toner for developing an electrostatic image using polyester has a problem that even in the above-mentioned toner manufacturing method suitable for industrialization, it is not possible to satisfactorily control the particle shape while having a sharp particle size distribution. . In addition, a method has been proposed in which amorphous toner is formed into a spherical shape by means such as a spray drier or hot water heating.However, since particles may be united by heat, a large number of non-spherical particles may be mixed or the particle size may be reduced. There were problems such as a broad distribution.

Generally, the transfer efficiency is improved when the electrostatic charge image developing toner has a spherical shape and a smooth surface. This is because the non-electrostatic adhesive force is reduced because the toner particles contact the transfer member at only one point. When such a toner is used, residual toner hardly occurs, and the possibility of realizing a cleaner-less system is increased. In addition, damage and abrasion of the photoconductor by toner particles are reduced, and the life of the photoconductor is extended. There is an advantage that it can be done. On the other hand, when the particle diameter is uniform, the electrostatic image developing toner generally has the following advantages. (1) The toner becomes sharply charged. As a result, the charge amount can be reduced, and the rise of the toner concentration with respect to the applied voltage becomes sharp, so that the applied voltage can be reduced. As a result, the life of the photoconductor can be extended. Further, since the light amount of the light emitting diode required for erasing the latent image can be reduced, the life of the light emitting diode used can be improved. (2) Selective development is reduced. This is because the amount of fine powder that causes the spent toner is small, and as a result, the life of the developer can be extended. (3) Transfer efficiency to a transfer target such as paper is improved. This is due to the small amount of fine powder having a large non-electrostatic adhesion, and as a result, a cleaner-less system can be realized. (4) Cleaning defects can be improved. Since there are few fine powders that cause poor cleaning, a simple cleaning system is sufficient, and scratches and abrasion of the photoreceptor are reduced to extend the life of the photoreceptor. From the above various advantages, there is a strong demand for a method of obtaining toner particles for developing an electrostatic image having a uniform particle size, a spherical particle shape, and a smooth surface.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above situation in the prior art.
That is, the object of the present invention is a toner having an extremely narrow particle size distribution, and having a spherical particle and a smooth surface for developing an electrostatic image image, and a narrow particle size distribution while controlling the particle size without classification. Another object of the present invention is to provide a method for producing a toner for developing an electrostatic image, which can easily and stably obtain a toner for developing an electrostatic image having a spherical shape. It is another object of the present invention to provide a toner for developing an electrostatic charge image and a method of manufacturing the same, in which the transfer efficiency is improved and the possibility of a cleanerless system is increased because no residual toner is generated. It is another object of the present invention to provide a toner for developing an electrostatic image capable of extending the life of the photoconductor by reducing the damage and abrasion of the photoconductor, and a method of manufacturing the same.

[0008]

The present inventors have conducted intensive studies on a method for producing a toner for developing an electrostatic image containing a binder resin and a colorant.
After adding the specific component, the solvent is removed from the suspension to have a sharp particle size distribution, and the shape of the particles is spherical, the surface is smooth, and the shape variation between the particles is reduced. The present inventors have found that a toner for developing an electrostatic charge image is generated, and have completed the present invention.

That is, according to the present invention, the amount of the residual solvent is 1 to 5
00 ppm, the GSD value is 1 or more and 1.6 or less, the sphericity is 100 or more and 130 or less, the lobe-like particle abundance is 0% or more and 5% or less, and BE
An electrostatic image developing toner having a T specific surface area of 0.5 to ³ m ² / g.

Further, the present invention provides a process of dissolving or dispersing a binder resin and a colorant in a solvent, and dispersing the obtained composition mixture in an aqueous medium containing surface-treated hydrophilic inorganic fine particles. In a method for producing a toner for developing an electrostatic image, comprising a step of suspending, and a step of removing a solvent from the obtained suspension, after the step of dispersing and suspending, the step of removing the solvent before the step of removing the solvent. Characterized in that an ionic substance is added thereto.

At this time, it is preferable that the temperature of the dispersion in the step of removing the solvent is not higher than the glass transition point (Tg) of the binder resin.

At this time, the peripheral speed of the stirring in the step of removing the solvent is preferably 10 to 70 m / min.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a toner for developing an electrostatic image and a method for producing the toner for developing an electrostatic image of the present invention will be described in detail. The toner for developing an electrostatic charge image of the present invention is a toner in which 1 to 500 ppm of a solvent remains in the toner due to its manufacturing characteristics, and has a GSD value (Geometrical Standard Deviation) indicating a particle size distribution of the toner of 1 to 1. 1．
6. The toner for developing an electrostatic image in the range of 6, and the value indicating the degree of sphericity of the toner is in the range of 100 to 130, and the lobe-like particle abundance is 0 to 5% by number. And an electrostatic charge image developing toner having a BET specific surface area of 0.5 to ³ m ² / g. Here, the GSD value is the degree of spread of the variation in the particle diameter of all toner particles calculated from (50% number average particle diameter of all toner particles) / (84% number average particle diameter of all toner particles). (Particle size distribution) is one or more values, and as this value approaches 1, it means that the particle size is monodisperse. In general, a monodisperse particle has a GSD value of about 1.1. belongs to. Normally used toners have a GSD value of about 1.7, but in order to improve the performance of the toner and obtain a higher quality image, lower the GSD value of the toner, Is preferably narrow.

The degree of sphericity is defined as a degree of sphericity = 10.
0 × π × (ML) ² / (4 × A) [where ML is the maximum length of the toner particles calculated from the two-dimensional projection image of the particles input from the optical microscope by the image analyzer, and A is the toner particle. The projected area calculated from the projected area of the toner particles is a value indicating the degree of sphericity of the toner particles. The closer the value is to 100, the more the shape is a true sphere. The shape is around 110. In practice,
A toner particle having a sphericity of 100 or more and 130 or less is good,
When the degree of spheroidization exceeds 130, the contact area between the photoconductor and the toner increases, so that the transferability decreases. Especially 100 or more 1
It is preferably 20 or less.

[0015] Lobe-shaped particles are irregularly shaped particles having a shape in which several particles are attached and having projections on the surface. Projection image of toner particles (SEM photographed at 1000x)
In (Photo), particles having protrusions of 20% or more of the diameter of the inscribed circle of the particles were defined as lobe-shaped particles. 10 random particles
Zero was selected, the number of lobe-like particles was counted, and this was expressed in number%, which was defined as the degree of shape variation. These lobe-shaped particles have a large contact area between the photosensitive pair and the toner, and therefore have poor transferability. In practice, the number is preferably 0 to 5% by number, and particularly preferably 0 to 2% by number. In the toner for developing an electrostatic image of the present invention, the GSD value is 1 or more and 1.6 or less, so that the amount of fine powder is small and the toner can be uniformly charged. It is possible to extend the life and improve the transfer efficiency, and it is possible to stably obtain a high-quality image without fog for a long period of time. The GSD value of the toner for developing an electrostatic image of the present invention is preferably as close to 1 in the above range as possible, but the lower limit of the GSD value is one of the GSD values adopted in Examples described later, Alternatively, a numerical range having an upper limit of any of the GSD values adopted in the examples described later is also preferable.

Further, in the toner for developing an electrostatic image of the present invention, the value of the degree of sphericity is 100 or more and 130 or less, and therefore, the spherical shape and the lobe-like particle abundance are 0% by number or more. When the content is 5% by number or less, the contact area of the toner with the photoconductor is small, so that high transfer efficiency is exhibited. Further, when such a toner is used, the residual toner hardly occurs and the possibility of a cleaner-less system is increased, and the damage and abrasion of the photoconductor by toner particles are reduced, and the life of the photoconductor is extended. Can be done.

Further, in the electrostatic image developing toner of the present invention, the BET specific surface area is 0.5 to ³ m ² / g, and more preferably 0.5 to 1.5 m ² / g. Further, the electrostatic image developing toner of the present invention needs to contain a solvent in the range of 1 to 500 ppm, and the fact that the solvent is contained in the toner in this range means that This is a characteristic of the electrostatic image developing toner. The solvent herein is the same as the solvent used as a dispersion medium in the mixing step of dissolving or dispersing the binder resin and the colorant.
When the solvent concentration is less than 1 ppm, the suitability for production of the toner is reduced, and the toner surface is liable to be deteriorated due to drying over a long period of time. ,Also,
It is not preferable because agglomeration easily occurs during storage of the toner and contaminants easily migrate from the inside to the surface.

The particle diameter of the toner for developing an electrostatic image of the present invention is preferably in the range of 1 to 30 μm.
Those having a range of 3 to 15 μm are more preferable. If the particle size is less than 1 μm, the surface area becomes large and carrier contamination tends to occur. As a result, the durability of the developer tends to decrease. If the particle size exceeds 30 μm, faithful reproducibility of dots tends to deteriorate, and Is not preferred because it becomes coarse.

Next, in the method for producing a toner for developing an electrostatic image of the present invention, the above-described steps will be sequentially described. First, the first step in the present invention is a mixing step of mixing a toner material in a solution to obtain a mixed liquid of the toner material. In this mixing step, a toner material containing at least a binder resin and a colorant is dissolved or dispersed in a solvent to obtain a mixed liquid of the toner materials.

The toner material may optionally contain, in addition to the binder resin and the colorant, a release agent and a charge control agent which are usually added to the toner particles, if necessary. The liquid mixture of the toner material may be obtained by previously kneading a binder resin with a colorant, a release agent, a charge control agent, and the like, or may be dissolved or dispersed in a solvent, or the binder resin may be dissolved in the solvent. After dissolving, a colorant, a release agent, a charge control agent and the like may be dispersed using a disperser with a medium such as a ball mill or a sand mill, or a high-pressure disperser. In this mixing step, as long as the binder resin is dissolved in the solvent and the colorant is dispersed,
Mixing may be performed by any method.

The binder resin of the toner for an electrostatic latent image developer according to the present invention is not particularly limited, and a resin generally used as a resin for a toner can be used. Specifically, polyester resin, styrene resin, acrylic resin, styrene-acrylic resin, silicone resin, epoxy resin, diene resin, phenolic resin, ethylene-vinyl acetate resin, etc. From the viewpoint of smoothness of the obtained image, a polyester resin is more preferable.

The following can be mentioned as the polymerizable monomer of the polyester resin. Examples of the alcohol component include polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3,3) -2,2-bis (4-hydroxyphenyl) propane, Oxyethylene (2,0) -2,
2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2,0) -polyoxyethylene (2,
Diols such as 0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2,0) -polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane, Ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, isopentyl glycol, dipropylene glycol, isopentyl glycol, hydrogenated bisphenol A, 1,3-butanediol, 1,4-butanediol , Neopentyl glycol, xylylene glycol,
1,4-cyclohexanedimethanol, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, bis- (β-hydroxyethyl) terephthalate, tris- (β-hydroxyethyl) isocyanurate, 2,2,4-trimethylol Pentane
1,3-diol and the like. Further, a hydroxycarboxylic acid component can be further added to the alcohol component in order to impart properties of the polyester resin.
For example, p-oxybenzoic acid, vanillic acid, dimethylolpropionic acid, malic acid, tartaric acid, 5-hydroxyisophthalic acid and the like.

Specific examples of the acid component include malonic acid, succinic acid, glutaric acid, dimer acid, phthalic acid, isophthalic acid, terephthalic acid, dimethyl isophthalate, dimethyl terephthalate, monomethyl terephthalate, tetrahydroterephthalic acid , Methyltetrahydrophthalic acid, hexahydrophthalic acid, dimethyltetrahydrophthalic acid, endomethylene hexahydrophthalic acid, naphthalenetetracarboxylic acid, diphenolic acid, trimellitic acid, pyromellitic acid, trimesic acid, cyclopentanedicarboxylic acid, 3, 3 ′, 4,4′-benzophenonetetracarboxylic acid, 1,2,3,4-butanetetracarboxylic acid, 2,2-bis- (4-carboxyphenyl) propane, trimellitic anhydride and 4,4- From diaminophenylmethane Ring obtained from trimerization product of diimide carboxylic acid, tris- (β-carboxyethyl) isocyanurate, polyimide carboxylic acid containing isocyanurate ring, tolylene diisocyanate, xylylene diisocyanate or isophorone diisocyanate, and trimellitic anhydride Containing polyimide carboxylic acid, and one or more of these are used. Of these, the use of a crosslinking component such as a trivalent or higher polyhydric carboxylic acid or polyhydric alcohol may be preferable in terms of stability such as fixing strength and offset resistance.

The polyester resin obtained from these raw materials is produced by a usual method. Glass transition temperature is 40
C. to 80.degree. C., more preferably 50.degree.
C. to 70C. Two or more of the above polyester resins may be combined with the resin of the present invention, and other resins may be combined as long as the effects of the present invention are not impaired. Other resins include styrene resin, acrylic resin, styrene-acryl resin, silicone resin, epoxy resin, diene resin, phenol resin, terpene resin, coumarin resin, amide resin, amide imide resin, butyral resin, urethane resin, and ethylene- There are vinyl acetate resins and the like. In the present invention, the polyester resin is the main component, and the other resin is contained in the binder resin in an amount of 0 to 30% by weight.
Is preferably added.

In the present invention, known organic or inorganic pigments and dyes and oil-soluble dyes can be used as the colorant dispersed in the thermoplastic resin.
For example, C.I. I. Pigment Red 48: 1, C.I. I. Pigment Red 57: 1, C.I. I. Pigment Red 1
22, C.I. I. Pigment Yellow 17, C.I. I. Pigment Yellow 97, C.I. I. Pigment Yellow 1
2, C.I. I. Pigment Blue 15: 1, C.I. I. Pigment Blue 15: 3, Lamp Black (CIN
o. 77266), Rose Bengal (CI No. 4)
5432), carbon black, nigrosine dye (C.I.
I. No. 50415B), metal complex salt dyes, derivatives of metal complex salt dyes, and mixtures thereof.
Furthermore, silica, aluminum oxide, magnetite and various ferrites, cupric oxide, nickel oxide, zinc oxide,
Various metal oxides, such as zirconium oxide, titanium oxide, and magnesium oxide, and a suitable mixture thereof are included.

These colorants need to be contained in a sufficient ratio to form a visible image having a sufficient density, and depend on the toner particle size and the development amount. A ratio of about 50% by weight is appropriate.

In the present invention, a charge control agent may be added to the toner if necessary. Usable charge control agents include metal salts of benzoic acid, metal salts of salicylic acid, metal salts of alkyl salicylic acid, metal salts of catechol, metal-containing bisazo dyes, and tetraphenylborate derivatives used in powder toners , Quaternary ammonium salts and alkylpyridinium salts, and those suitably combined with each other.

The addition amount of these charge control agents to the toner is generally in the range of 0.1% by weight to 10% by weight, more preferably 0.5% to 8% by weight. 0.1% by weight
If the ratio is less than 10%, the charge control effect is insufficient, and if it exceeds 10% by weight, the toner resistance is excessively reduced, and the toner becomes difficult to use.

Further, a metal soap, an inorganic or organic metal salt can be used in combination with the charge control agent. Such metal soaps include aluminum tristearate, aluminum distearate, barium, calcium, lead and zinc stearate, or cobalt,
Manganese, lead and zinc linolenate, aluminum,
Calcium, cobalt octanoate, calcium and cobalt oleate, zinc palmitate, calcium, cobalt, manganese, lead and zinc naphthenates,
Resinates of calcium, cobalt, manganese, lead and zinc can be used. Further, as the inorganic or organic metal salt, for example, the cationic component in the metal salt is selected from the group consisting of metals of Groups Ia, IIa, and IIIa of the periodic table, and an anion of the acid. The sexual component is a salt selected from the group consisting of halogen, carbonate, acetate, sulfate, borate, nitrate, and phosphate. These metal soaps, inorganic or organic metal salts generally range from 0.1% to 10%, more preferably from 0.1% to 5% by weight per toner.
If the amount is less than 0.1% by weight, the desired effect is insufficient, and if it exceeds 10% by weight, the fluidity of the toner powder is reduced, and both are not preferred.

In the present invention, the solvent used for dissolving or dispersing the toner material includes ester solvents such as methyl acetate, ethyl acetate, propyl acetate and butyl acetate; ether solvents such as diethyl ether, dibutyl ether and dihexyl ether; Examples include ketone solvents such as methyl ethyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, and cyclohexanone; hydrocarbon solvents such as toluene, xylene, and hexane; and halogenated hydrocarbon solvents such as dichloromethane, chloroform, and trichloroethylene. It is preferable that these solvents are capable of dissolving the binder resin and have a water-soluble ratio of about 0 to 30% by weight. In addition, when industrialization is performed, in consideration of work safety, cost, productivity, etc., cyclohexane is used when the binder resin is a polyolefin, and ethyl acetate is used when the other binder resin is used. It is particularly preferred to use These solvents have a viscosity of 1 to 10,000 at 20 ° C.
mPas used to be in the range, preferably 1 to 200
It is used to be in the range of 0 mPa · s.

Next, the second step of the present invention is a dispersion and suspension step of dispersing and suspending a mixture of toner materials. In this dispersion suspension step, a liquid mixture of the toner material obtained in the mixing step is introduced into an aqueous medium to obtain a suspension. As the aqueous medium, it is preferable to use one in which hydrophilic inorganic fine particles (inorganic dispersant) are dispersed in water. Further, in order to make the particle size distribution of the toner particles uniform, while dispersing the hydrophilic inorganic fine particles in water,
It is preferable to add a polymer dispersant that dissolves in water.
The hydrophilic inorganic fine particles are dispersed in water using a disperser containing a medium such as a ball mill, a high-pressure disperser, an ultrasonic disperser, or the like. The polymer dispersant may be added by any method as long as it is uniformly dissolved in water. The water used in the present invention is usually ion-exchanged water, distilled water or pure water, but it is more preferable to use water saturated with a water-soluble solvent.

Specific examples of the above-mentioned hydrophilic inorganic fine particles include silica, alumina, titania, calcium carbonate,
Examples thereof include magnesium carbonate, tricalcium phosphate, clay, diatomaceous earth, bentonite and the like. Among them, calcium carbonate is particularly preferred. Furthermore, in the production method of the present invention, from the viewpoint of further improving dispersibility and stability during dispersion, the hydrophilic inorganic fine particles include inorganic fine particles coated with a polymer having a carboxyl group on the particle surface. It is more preferable to use. By using inorganic fine particles coated with a polymer having a carboxyl group, the lipophilic-hydrophilic balance can be optimized, so that the aqueous phase component and the oil phase component are stabilized, and each of the components contained in the dispersion medium is stabilized. The toner components can be uniformly dispersed, and this state can be maintained. Therefore, by using the inorganic fine particles coated with the polymer as described above, uniform toner particles can be formed, and a stable toner having a narrow particle size distribution can be manufactured. Therefore, in the present invention, it is most preferable to use calcium carbonate coated with a polymer having a carboxyl group.

Examples of the polymer having a carboxyl group include α, β monoethylenically unsaturated carboxylic acids or α, β
At least one selected from an alkali metal salt, an alkaline earth metal salt, an ammonium salt, an amine salt, and the like, in which the carboxyl group of the β-monoethylenically unsaturated carboxylic acid is neutralized with an alkali metal, an alkaline earth metal, ammonium, an amine, or the like. Copolymer of seed and α, β monoethylenically unsaturated carboxylic acid ester, or copolymer of α, β monoethylenically unsaturated carboxylic acid ester and α, β monoethylenically unsaturated carboxylic acid ester And the above-mentioned alkali metal salts, alkaline earth metal salts, ammonium salts and amine salts. These may be used alone,
You may mix and use more than one kind.

Representative examples of the above α, β monoethylenically unsaturated carboxylic acids include α, β unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid and the like. And at least one selected from α, β unsaturated dicarboxylic acids. Representative examples of the α, β monoethylenically unsaturated carboxylic acid esters include acrylic acid, methacrylic acid and other alkyl esters, acrylates and methacrylates having an alkoxy group, acrylates having a cyclohexyl group, and Methacrylates, acrylates and methacrylates having a hydroxy group,
Examples thereof include polyalkylene glycol monoacrylates and polyalkylene glycol monomethacrylates, and those selected from α and β monoethylenically unsaturated carboxylic acid esters represented by these are preferable.

As the above-mentioned hydrophilic inorganic fine particles, those having an average particle size in the range of 1 to 1000 nm are used.
Those having a range of 500 nm are preferable, and those having a range of 10 to 300 nm are more preferable. If the average particle size is less than 1 nm, it becomes difficult to disperse the inorganic fine particles. If the average particle size exceeds 1000 nm, the difference from the toner particle size becomes small, so that the mixed liquid (oil phase component) of the toner composition is stably dispersed. It is not preferable because it becomes difficult to maintain.

The hydrophilic inorganic fine particles are preferably used in an amount of 1 to 300 parts by weight, more preferably 4 to 100 parts by weight, based on 100 parts by weight of the toner. If the amount is less than 1 part by weight, sufficient dispersibility and stability cannot be obtained. If the amount exceeds 300 parts by weight, the viscosity of the aqueous medium (aqueous phase component) tends to be high, and dispersion and suspension cannot be achieved. It is not preferable because it may be stable.

As the above-mentioned polymer dispersant, it is preferable to use a hydrophilic dispersant, and among those having a carboxyl group, those having no lipophilic group such as a hydroxypropoxyl group and a methoxyl group are particularly preferable. In particular,
Water-soluble cellulose ethers such as carboxymethylcellulose and carboxyethylcellulose are used, and among them, carboxymethylcellulose is preferable.

The water-soluble cellulose ether has a degree of etherification in the range of 0.6 to 1.5 and an average degree of polymerization of 50 to 3000.
Are preferred. Also, the carboxyl group contained is
Metal salts such as sodium, potassium and magnesium may be used. These polymer dispersants have an optimal amount depending on the polarity of the liquid mixture of the toner material. If the amount is larger or smaller than the optimum amount, the particle size distribution of the formed particles will not be sharp.

The apparatus used in the dispersion suspension step includes:
Generally, the emulsifier and the disperser are not particularly limited as long as they are commercially available.For example, Ultra Turrax (IKA), Polytron (Kinematica), T
Batch-type emulsifiers such as K-auto homomixer (manufactured by Tokushu Kika Kogyo), National Cooking Mixer (manufactured by Matsushita Electric Industrial), Ebara Milder (manufactured by Ebara Corporation), TK pipeline homomixer, TK homomix line Flow (manufactured by Tokushu Kika Kogyo Co., Ltd.), colloid mill (manufactured by Shinko Pantec Co., Ltd.), slasher, trigonal wet pulverizer (manufactured by Mitsui Miike Kakoki), Cavitron (manufactured by Eurotech), fine flow mill (manufactured by Taiheiyo Kiko Co., Ltd.) ), Etc., batch or continuous dual-use emulsifier such as CLEARMIX (manufactured by M-Technic), FILMIX (manufactured by Tokushu Kika Kogyo), microfluidizer (manufactured by Mizuho Industry), nanomaker, nanomizer (Manufactured by Nanomizer Co., Ltd.), high-pressure emulsifier such as APV gourin (manufactured by Goulin Co.), membrane emulsifier such as membrane emulsifier (manufactured by Reika Kogyo), vibro mixer (manufactured by Reika Kogyo) Vibrating emulsifier, and an ultrasonic emulsifying machine such as an ultrasonic homogenizer (manufactured by Branson Co.).

The third step is an ionic substance addition step. In this ionic substance addition step, it is necessary to adjust the balance between hydrophilicity and lipophilicity of the aqueous medium in the suspension by adding an ionic substance to the suspension prepared in the dispersion suspension step. It is. This is because of the level of balance between hydrophilicity and lipophilicity for obtaining a sharp particle size distribution in the above-mentioned dispersion suspension process, and hydrophilicity for obtaining a spherical toner in the process of removing the solvent in the suspension. This is because the balance between the hydrophilicity and the lipophilicity can be changed by adding an ionic substance to the suspension after the dispersion and suspension step. Therefore, in order to obtain spherical toner particles having a sharp particle size distribution, it is necessary to add an ionic substance to the suspension after the dispersion and suspension step. The addition of the ionic substance may be performed immediately after the dispersion and suspension, but it is preferable to perform the addition after 1 to 5 minutes or more in the dispersion and suspension step in order to sharpen the particle size distribution.

As the ionic substance used in the present invention, those which have good solubility when added to an aqueous phase and which relatively increase the hydrophilicity of the aqueous phase by dissociation can be used. Any material may be used, such as an alkali metal or alkaline earth metal hydroxide, aqueous ammonia, and a substance having a hydrophilic group such as a carboxyl group or a hydroxyl group. More specifically, hydroxides of alkali metals include sodium hydroxide, potassium hydroxide, lithium hydroxide and the like, and carbonates and acetates thereof, and hydroxides of alkaline earth metals include magnesium hydroxide, Calcium hydroxide and the like. Among these, ammonia water is more preferred. In addition, those that are difficult to dissolve in water and those that have high viscosity, such as some metal hydroxides, are not suitable because they are difficult to remove during washing with water. These may be used alone or as a mixture of two or more. The amount of the ionic substance added is 0.1 to 0.1% in terms of a 1% aqueous solution of the ionic substance with respect to 100 parts by weight of the suspension prepared in the dispersion suspension step.
It is preferable to add in the range of 100 parts by weight,
More preferably, it is added in an amount of from 25 to 25 parts by weight. If the addition amount is less than 0.1 part by weight, a sufficient degree of spheroidization cannot be obtained, and if it exceeds 100 parts by weight, coalescence or aggregation of particles occurs, changes in particle diameter, particle size distribution, and irregular shaped particles. Is not preferred because of the occurrence of

The fourth step is a solvent removing step. The solvent removing step is a step of removing the solvent in the liquid prepared in the ionic substance adding step to prepare a toner dispersion. In the solvent removing step, it is preferable to remove the solvent contained in the droplet by heating the liquid prepared in the ionic substance adding step. At this time, the higher the heating temperature, the faster the solvent can be removed, but the glass transition point (T
g) It must be: This is because when the heating temperature exceeds the glass transition point (Tg) of the binder resin, the hydrophilic inorganic fine particles adhering to the toner particle interface are immersed in the toner when the solvent is removed, and as a result, the toner surface This is because it adversely affects the toner characteristics such as unevenness and chargeability. Further, at this time, the peripheral speed of the stirring needs to be 10 to 70 m / min. This is because the toner particles in the early stage of the solvent removal step are droplets, and the inorganic fine particles are present at the interface with the aqueous medium, forming particles, and are susceptible to shearing by stirring, In addition, by adding an ionic substance for spheroidization, it becomes more susceptible to agitation, and in the range exceeding a peripheral speed of 70 m / min, particles are torn off, fine powder is generated, and toner This is because the particle size distribution becomes broad. At this time, (1) pressure 7
The gas phase on the liquid surface is forcibly updated by exhaust air with the pressure of 60 mmHg or more (at this time, gas may be blown into the liquid).
(2) Reduce the pressure to less than 10 to 760 mmHg (at this time, the gas phase on the liquid surface may be forcibly updated by purging the gas,
Gas may be blown into the liquid). They may be performed alone or sequentially.

In the method for producing a toner for developing an electrostatic image according to the present invention, the following steps can be added as necessary. First, the aqueous medium is removed from the toner dispersion liquid produced in the fourth solvent removing step, washed and dehydrated to produce a toner cake. This wash,
In the dehydration step, the dispersion prepared in the solvent removal step is treated with an acid to dissolve the inorganic fine particles, and then washed with water and dehydrated. However, an alkali treatment may be added after the acid treatment. Further, the next step is a step of drying the toner cake produced in the washing and dehydrating step, sieving and adding an external additive to produce a toner for developing an electrostatic image. In these steps, drying, sieving, and external addition may be performed by any method as long as the method does not cause aggregation or pulverization of the toner.

[0044]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. In the following description, “parts” means “parts by weight”.

Example 1 <Mixing Step (First Step)> The following composition was dispersed in a ball mill for 24 hours to obtain 200 parts of a toner composition mixed solution in which a polyester resin was dissolved.・ Bisphenol A propylene oxide adduct / 90 parts Bisphenol A ethylene oxide adduct / terephthalic acid derivative copolymerized polyester resin (glass transition point Tg66 ℃, melting point Tm106 ℃) ・ C. I. Pigment Blue (15: 3) 5 parts ・ Paraffin wax (melting point 89 ° C) 5 parts ・ Ethyl acetate 100 parts

<Dispersion and Suspension Step (Second Step)> The following composition was dispersed in a ball mill for 24 hours to dissolve carboxymethylcellulose to obtain an aqueous medium.・ Calcium carbonate (coated with acrylic acid-based copolymer) 20 parts (trade name: Luminous, manufactured by Maruo Calcium Co., Ltd.) ・ Carboxymethyl cellulose 0.5 part (trade name: Cellogen BS-H, manufactured by Daiichi Kogyo Co., Ltd.)・ 99.5 parts of ion exchange water

1200 g of the aqueous medium obtained above was placed in a TK auto homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), and the rotating blades were stirred at a peripheral speed of 20 m / sec. , The above-mentioned toner composition mixed solution 100 g was added, and 25 ° C.
Stirring was maintained for 1 minute while maintaining constant to obtain a dispersion suspension.

<Ionic Substance Addition Step (Third Step)> While stirring the dispersion suspension obtained above with a propeller blade, 150 g of 1% diluted aqueous ammonia was added.

<Solvent Removal Step (Fourth Step)> While stirring the mixture obtained in the ionic substance addition step at a peripheral speed of 45 m / min, the temperature was kept constant at 40 ° C., and the mixture was dispersed and suspended using a prower. The gas phase on the liquid surface was forcibly renewed and kept for 17 hours to obtain a toner dispersion liquid (1).

<Washing and Dehydration Steps> To 300 parts by weight of the toner dispersion liquid (1) obtained in the solvent removing step, 80 parts by weight of 10N hydrochloric acid was added, and the mixture was neutralized with a 0.1N aqueous sodium hydroxide solution. Then, wash the ion-exchanged water with suction filtration.
This was repeated four times to obtain a toner cake (1).

<Drying and Settling Step> The toner cake (1) obtained above was dried with a vacuum dryer and cut with a 45 μm mesh to obtain a toner (1) for electrostatic image development.

<Measurement of Residual Solvent Amount> To 1 part by weight of the toner for electrostatic charge development (1) obtained above, 2 parts by weight of 2-propanol was added, and the toner for electrostatic charge development (1) was added by ultrasonic wave to 2 parts by weight. −
After dispersing in propanol for 30 minutes, the mixture was stored in a refrigerator for at least one day to extract the solvent in the toner. The supernatant was analyzed by gas chromatography (GC14A, SHIMADZU), and the solvent concentration in the toner was determined by quantifying the solvent in the toner.
Here, the measurement conditions are as follows. · Apparatus; Shimadzu GC-14A, Column; CBP20-M50-0.25 · Detector: FID, injection volume; 1～5Myueru-carrier gas; He2.5kg / cm ² · hydrogen flow rate; 0.6 kg / cm ² · air Flow rate: 0.5 kg / cm ² · Chart speed: 5 mm / min · Sensitivity: Range 10 x Att en 2 ° · Column temperature: 40 ° C · Injection Temp: 150 ° C

<Measurement of Particle Size and Particle Size Distribution> The particle size and the particle size distribution of the electrostatic image developing toner (1) obtained above were measured using a Coulter Multisizer II (manufactured by Coulter KK) to a particle size of 50 μm. It was measured by aperture diameter.
Here, the particle size is represented by the weight average particle size, and the scale indicating the width of the particle size distribution is GSD (Geometrical Standard Deviation, (50% number average particle size of all toner particles) / (84% number of total toner particles) Average particle size)).

<Measurement of the degree of sphericity> The degree of sphericity of the toner for developing an electrostatic image (1) obtained above was expanded to 500 times magnification using an FE-SEM (S-800, manufactured by Hitachi, Ltd.). 100 toner images obtained at random are sampled, and the image information is sent via an interface to an image analysis device (Nireco Lu:
zexIII), analyzed, and represented by a value (shape factor value: MLS2) calculated by the following equation. MLS2 = (absolute maximum length of toner particles) ² / (projected area of toner particles) × π × １ ／ × 100 Further, magnification was increased to 1000 times using FE-SEM (S-800, manufactured by Hitachi, Ltd.). The number of lobe-shaped particles in 100 randomly selected from the obtained toner images and the measurement with a BET specific surface area measuring device (SA3100, manufactured by Coulter, Inc.) were also performed.

Further, using the toner (1) for developing an electrostatic image of the present invention obtained above, an electrophotographic copying machine (trade name: V)
ivace555, manufactured by Fuji Xerox Co., Ltd.).

<Evaluation of Transferability> The surface of the photoconductor immediately after the transfer to paper was observed, and residual toner (toner remaining on the photoconductor) was observed.
The waste toner (toner scattered to a place other than the photoreceptor) was visually evaluated according to the following criteria. ：: Good transferability without residual toner on the photoreceptor surface and waste toner. Δ: There are some residual toner and waste toner on the photoreceptor surface,
It is practical. C: Remaining toner on the photoreceptor surface is remarkably observed, and a large number of waste toners are also observed.

<Evaluation of Image Quality> The obtained images were visually evaluated according to the following criteria. ：: A stable image with no fog on the background and no image omission. Δ: Fog and image defects are slightly present in the background, but practical. ×: Fogging of the background portion is remarkable, and image defects are also observed.

(Example 2) In Example 1, the ionic substance added in the <ionic substance addition step (third step)> was changed from 150 g of 1% diluted aqueous ammonia to 6 g of 1% aqueous sodium hydroxide solution. A toner (2) for developing an electrostatic charge image was obtained in the same manner as in Example 1 except for the above. The residual solvent amount, particle size, particle size distribution, sphericity, BET specific surface area, and lobe-like particle abundance of the obtained electrostatic image developing toner (2) were measured in the same manner as in Example 1 above. In addition, the surface of the photoreceptor immediately after the transfer to paper was observed in the same manner as in Example 1, and a sensory evaluation was visually performed on the remaining toner and waste toner, and a copy image was prepared. The image quality and fog were evaluated.

(Examples 3 to 5) The procedure of Example 1 was repeated except that the temperature and the peripheral speed of the stirring during the solvent removal in the <solvent removal step (fourth step)> were set to the values shown in Table 1. Similarly, electrostatic image developing toners (3) to (5) were obtained. The residual solvent amount, particle size, particle size distribution, sphericity, BET specific surface area, and lobed particle abundance of the obtained electrostatic charge image developing toners (3) to (5) were determined in the same manner as in Example 1 above. It was measured. Also, in the same manner as in Example 1, the surface of the photoreceptor immediately after transfer to paper was observed, and a sensory evaluation was performed visually on the remaining toner and waste toner, and a copy image was prepared.
The image quality and fog were evaluated in the same manner as in Example 1.

Comparative Example 1 A toner (6) for developing an electrostatic image was obtained in the same manner as in Example 1 except that the step of adding an ionic substance was omitted. The residual solvent amount, particle size, particle size distribution, sphericity, BET specific surface area, and lobed particle abundance of the obtained electrostatic image developing toner (6) were measured in the same manner as in Example 1 above. Also,
The surface of the photoreceptor immediately after the transfer to paper was observed in the same manner as in Example 1, and a sensory evaluation was visually performed on the remaining toner and waste toner, and a copy image was prepared. And evaluation of fog.

(Comparative Example 2) In the method of Example 1, except that the step of adding the ionic substance was omitted, the stirring peripheral speed at the time of removing the solvent was changed.
A toner (7) for electrostatic image development was obtained in the same manner as in Example 1 except that the speed was changed to 120 m / min. The residual solvent amount, particle size, particle size distribution, sphericity, BET specific surface area, and lobe particle abundance of the obtained electrostatic image developing toner (7) were measured by the same methods as in Example 1 above. In addition, the surface of the photoreceptor immediately after the transfer to paper was observed in the same manner as in Example 1, and a sensory evaluation was visually performed on the remaining toner and waste toner, and a copy image was prepared. The image quality and fog were evaluated.

(Comparative Example 3) In the method of Example 1, except that the ionic substance addition step was carried out and the heating and spheroidizing treatment (350 ° C.) was carried out by a hot air treatment device after the <drying / segmentation step>. In the same manner as in Example 1, an electrostatic image developing toner (8) was obtained. Residual solvent amount, particle size, particle size distribution, sphericity, BE of the obtained electrostatic image developing toner (8)
The T specific surface area and the lobed particle abundance were measured in the same manner as in Example 1 above. Further, in the same manner as in Example 1, the surface of the photosensitive member immediately after the transfer to paper was observed, and the remaining toner and the waste toner were visually subjected to a sensory evaluation.
A copy image was prepared, and its image quality and fog were evaluated in the same manner as in Example 1.

Comparative Example 4 A conventional melt-kneaded and pulverized toner, which is used in Vivace400 (manufactured by Fuji Xerox Co., Ltd.), has a particle size, particle size distribution, sphericity, BE
The T specific surface area and the lobed particle abundance were measured in the same manner as in Example 1 above. Further, in the same manner as in Example 1, the surface of the photosensitive member immediately after the transfer to paper was observed, and the remaining toner and the waste toner were visually subjected to a sensory evaluation.
A copy image was prepared, and its image quality and fog were evaluated in the same manner as in Example 1.

(Comparative Example 5) In the method of Example 1, except for the step of adding an ionic substance, after the <drying and settling step>, a heating and spheroidizing treatment (350 ° C.) was performed by a hot air treatment device, and further a classifier was used. The toner (10) for developing an electrostatic image was obtained in the same manner as in Example 1 except that the particle size distribution was sharpened. The residual solvent amount, particle size, particle size distribution, sphericity, BET specific surface area, and lobe particle abundance of the obtained electrostatic image developing toner (10) were measured by the same methods as in Example 1 above. Also, the surface of the photoreceptor immediately after the transfer to paper was observed in the same manner as in Example 1, and a sensory evaluation of the remaining toner and waste toner was visually performed, and a copy image was prepared. The image quality and fog were evaluated.

[0065]

[Table 1]

Table 1 shows that the toner of this example has a narrow particle size distribution and a spherical shape, and is excellent in transferability and image quality.

[0067]

According to the method of the present invention, a toner for developing an electrostatic image having a sharp particle size distribution, a spherical shape and a smooth surface, containing a binder resin and a colorant. Can be easily produced. Further, according to the method of the present invention, the transfer efficiency is improved, the possibility of realizing a cleanerless system is increased, and a toner for developing an electrostatic image capable of eliminating waste toner can be easily produced. It is possible. Further, according to the method of the present invention, it is possible to easily produce a toner for developing an electrostatic image, which can reduce the damage and abrasion of the photoconductor and extend the life of the photoconductor.

Claims (2)

[Claims] Claims: 1. The residual solvent amount is 1 to 500 ppm,
And the GSD value is 1 or more and 1.6 or less, and the degree of sphericity is 1
00 to 130, the lobe-like particle abundance is 0 to 5% by number, and the BET specific surface area is 0.5 to 0.5%.
-3 m ² / g. 2. A step of dissolving or dispersing a binder resin and a colorant in a solvent, and a step of dispersing and suspending the obtained composition mixture in an aqueous medium containing surface-treated hydrophilic inorganic fine particles. And a method for producing a toner for developing an electrostatic image, comprising the step of removing a solvent from the obtained suspension, wherein the ionic substance is added to the suspension after the step of dispersing and suspending and before the step of removing the solvent. A process for producing a toner for developing electrostatic images, characterized by adding