JPH08137128A - Production of microtoner - Google Patents

Abstract

PURPOSE: To provide a method for producing a toner with high production efficiency by which the particle diameter of the produced toner is more easily controlled and the loss of a self-emulsifiable resin contg. a dispersed colorant on dissolution in water is reduced when a soln. of the resin in an org. solvent is brought into phase inversion and emulsification in water to produce the toner. CONSTITUTION: A resin (A) contg. a dispersed colorant (B) and made self- dispersible in water by neutralization and a smaller amt. of a neutralizing agent than the amt. required to disperse the resin A in water in a prescribed particle diameter are dissolved in an org. solvent to prepare a soln., water contg. at least the neutralizing agent by such an amt. as to attain the required amt. is added to the soln. and this soln. is brought into phase inversion and emulsification to obtain a dispersion liq. contg. toner particles made of a resin (C) self-dispersible in water and contg. the colorant B. The toner particles are dried by removing the dispersive medium.

Description

Detailed Description of the Invention

[0001]

The present invention relates to electrophotography, electrostatic recording,
The present invention relates to a method for producing a dry toner for developing an electrostatic latent image in electrostatic printing or the like.

[0002]

2. Description of the Related Art In electrophotographic toners which are widely used as image forming materials for copying machines, laser printers, fax machines and the like, the market demand for high image quality and high resolution is increasing. Is increasing.

Conventionally, both a dry process and a wet process have been known as a method for producing an electrophotographic toner. As a manufacturing method of the dry process, a method in which a binder resin and a colorant are melt-kneaded as essential components and then mechanically crushed and classified is widely used. By this method, toner particles having a polygonal shape with an angular shape instead of a spherical shape are obtained.

Generally, in the dry process of carrying out this mechanical pulverization / classification method, when an attempt is made to reduce the average particle diameter of the toner in order to increase the image resolution, the powder fluidity of the toner particles is remarkably reduced, resulting in There is a problem in that the toner transportability becomes unstable and an image with poor print quality is likely to be formed. Further, there is also a problem that the production capacity and the yield in the pulverizing and classifying step are significantly reduced, and the cost becomes relatively high.

On the other hand, a new toner such as a capsule toner or a polymerized toner has been proposed as a toner that overcomes the above drawbacks. Unlike the conventional dry process, these are manufactured by chemically reacting a monomer that becomes a binder resin in the presence of a colorant and then drying (polymerized toner), or by adding the colorant to an organic solvent solution of the binder resin. Toner particles are manufactured by a wet process such as dispersion (dispersion / water addition to water or phase inversion emulsification, solvent removal / dehydration and drying (capsule toner)). By these methods, spherical toner particles which are substantially close to a sphere can be obtained.

Here, most of the conventional wet processes require the use of a dispersion stabilizer because it is necessary to stably disperse toner particles in water. Specific examples of such dispersion stabilizers include polyvinyl alcohol, polyvinylpyrrolidone, hydroxyethyl cellulose, carboxymethyl cellulose, cellulose gum, silica powder, sodium lauryl sulfate, water-soluble polymer compounds such as sodium oleate, metal oxides, and surfactants. Etc. have been proposed. Although these dispersion stabilizers have an extremely effective effect on making the toner particles finer and making the particle size uniform, various dispersion stabilizers remain on the toner surface after washing and are difficult to completely remove. I had a problem. For example,
A wet process toner using such a dispersion stabilizer absorbs moisture in the air to reduce the electric resistance of the toner even after being dried and made into a powder toner, and makes the charge on the toner surface uneven. However, stable copying on plain paper becomes difficult.

On the other hand, a wet process which does not require the use of a dispersion stabilizer is disclosed in JP-A-5-66600. Here, toner particles stably dispersed in water are prepared by phase inversion emulsification of an organic solvent solution of an anionic self-water dispersible resin neutralized with a base containing a colorant into water. At that time, the particle size of the toner particles produced is controlled by the amount of an alkaline substance as a neutralizing agent that neutralizes the acid groups contained in the resin that can become self-water dispersible by neutralization.

[0008]

However, the particle size of the toner particles produced by such a phase inversion emulsification wet process is
It is extremely sensitive to the amount of the neutralizing agent added, and even if a slight increase or decrease changes the particle size, the toner particles of the same size cannot be repeatedly and reproducibly produced. Further, the resin itself has a high solubility in water, and a large amount of the resin dissolves in water without being taken up by the toner during phase inversion emulsification, which causes a problem of large raw material loss in production.

In view of the above circumstances, the present invention provides a method for producing a micro toner in which the particle size can be easily controlled and the raw material loss is small, and toner particles having stable and high productivity in a phase inversion emulsification wet process method are provided. It aims at providing the manufacturing method of.

[0010]

Means for Solving the Problems That is, the present inventor has conducted various studies on the phase inversion emulsification wet process in order to solve the above problems, and as a result, the neutralizer is a resin organic compound which can be self-water dispersible by neutralization. By carrying out phase inversion emulsification by dividing and containing both in the solvent solution and water used for phase inversion, it is possible to achieve the control of the toner particle size relatively easily, and to generate the resin that is not incorporated as a toner. The inventors have found that the amount can be reduced and reached the present invention.

That is, in the present invention, the colorant (A) is dispersed,
At least the above resin is dissolved in an organic solvent solution in which a resin (B) capable of becoming self-water dispersible by neutralization and a neutralizing agent in an amount less than that necessary to make the resin (B) dispersed in water with a predetermined particle size are dissolved. A self-water-dispersible resin (C) in which the colorant (A) is encapsulated by adding water containing an insufficient amount of a neutralizing agent required to disperse (B) in a predetermined particle size in water and emulsifying the phase. The present invention provides a method for producing toner particles composed of a self-water dispersible resin (C) containing a colorant, which comprises:

The toner particles obtained by the production method of the present invention may be toner particles composed of a self-water dispersible resin (C) containing a colorant, or may be self-water dispersible by neutralization containing a colorant. The toner particles are made of resin (B).

In the present invention, "encapsulation" means that the colorant (A) particles are the resin (B) or (in addition to the state in which the colorant particles are encapsulated in the resin (B) or (C). Those dispersed in C) are also included.

In the present invention, the colorant (A) is dispersed,
The resin (B), which can be self-water dispersible by neutralization, is neutralized with a neutralizing agent, and water is added to an organic solvent solution containing the resin (C) that is self-water dispersible, and then phase-inversion emulsification In the conventional method for producing toner particles by phase inversion emulsification, in which the solvent and water are removed and dried, the neutralizing agent used for neutralizing the resin (B) is defined as follows, where the total amount of the neutralizing agent is 1. Not only the organic solvent solution but also water used for phase inversion emulsification, and the neutralizing agent contained in the organic solvent solution is necessary for dispersing the resin (B) in water with a predetermined particle size. The amount of the neutralizing agent, which is insufficient in the organic solvent solution, is at least used in the water used during phase inversion emulsification.

As described above, the particles of the toner of the present invention are
The resin (B) or the self-water dispersible resin (C) capable of self-water dispersion by neutralization is used as a binder resin for toner. Here, the resin (B) capable of self-dispersing in water by neutralization is a resin containing in its molecule a functional group capable of becoming a hydrophilic group by neutralization, and some or all of these functional groups capable of becoming hydrophilic are intermediate. It refers to a resin that has the ability to form a stable aqueous dispersion without the use of an emulsifier when neutralized with a solvating agent.

In the case of anionic resins, the functional group capable of becoming a hydrophilic group by neutralization in the resin (B) includes, for example, so-called acidic groups such as carboxyl group, phosphoric acid group and sulfonic acid group. In the case of a cation type resin, examples thereof include so-called basic groups such as dimethylamino group and diethylamino group.

On the other hand, the self-water-dispersible resin (C) has a salt structure in which some or all of the functional groups of the self-water-dispersible resin (B) are neutralized by a neutralizing agent. Say resin.

Specific examples of the self-water dispersible resin (B) or self-water dispersible resin (C) by such neutralization include:
Acrylic resins, styrene resins, epoxy resins, urethane resins, polyamide resins, alkyd resins, polyester resins and the like can be mentioned. Among them, an acrylic resin, particularly a styrene / acrylate copolymer resin, which is relatively easy to obtain the balance of powder fluidity and fixing property as a toner, is preferable.

Specific examples of the styrene resin or acrylic resin include styrenes such as styrene, α-methylstyrene, chlorostyrene and vinylstyrene,
Monoolefins such as ethylene, propylene, butylene, isobutylene, diolefins such as butadiene and isoprene, vinyl acetate, propion vinyl, vinyl butyrate,
Vinyl esters such as vinyl benzoate, methyl acrylate, ethyl acrylate, butyl acrylate, octyl acrylate, phenyl dodecyl acrylate, methyl methacrylate, ethyl methacrylic acid butyl methacrylate, α-, such as dodecyl methacrylate. Acrylic monomers such as vinyl ethers such as methylene aliphatic monocarboxylic acid esters, vinyl methyl ether, vinyl ethyl ether, vinyl butyl ether, vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, vinyl propenyl ketone, acrylic acid, methacrylic acid , Crotonic acid, itaconic acid, maleic acid, fumaric acid, itaconic acid monobutyl, maleic acid monobutyl, acid phosphooxyethyl methacrylate, acid phosphooxypropyl methacrylate Copolymer with acid group-containing monomer such as 3-chloro-2-acrylamido-2-methylpropanesulfonic acid and 2-sulfoethylmethacrylate, or dimethylaminoethyl acrylate, diethylaminoethyl acrylate, dibutylaminoethyl acrylate, N-ethyl Examples thereof include a copolymer with a base-containing monomer such as -N-phenylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, dibutylaminoethyl methacrylate, N-ethyl-N-phenylaminoethyl methacrylate.

Further, when the anionic resin (B) is described in detail, a polymer unsaturated group-containing oligomer having an acid group can also be used as a copolymerization component, and maleic anhydride,
Obtained by polycondensation or addition condensation of fumaric acid, tetrahydrophthalic anhydride, endomethylenetetrahydromaleic anhydride, α-terpinene maleic anhydride adduct, etc. with a monoallyl ether of triol, pentaerythrite diallyl ether, allyl glycidyl ether, etc. Vinyl-modified polyesters, dimethylolpropionic acid, glycerin monoallyl ether, 1,2-butadienepolyol and other vinyl-modified urethanes obtained by addition polymerization of diisocyanate, glycidyl group-containing monomer added to carboxyl group-containing vinyl copolymer Examples thereof include vinyl modified epoxies.

As the polymerization initiator used for obtaining the resin (B), of course, usual ones can be used. For example, benzoyl peroxide, di-t-butyl peroxide,
There may be mentioned various peroxides such as cumene hydroperoxide, t-butyl peroxide or 2-ethylhexanoate; or various azo compounds such as azobisisobutyronitrile or azobisisovaleronitrile. .

The resin (B) may be obtained by solution polymerization in an organic solvent, suspension polymerization, emulsion polymerization, or bulk polymerization.

As the polyester resin, an acid group can be easily introduced into an ordinary polyester resin by using an excessive amount of a dibasic acid such as phthalic acid in the condensation of a polyol and a polybasic acid.

The content of the functional group capable of becoming an anionic hydrophilic group by the neutralization of the resin (B) is not particularly limited, but an acid value of about 40 or more facilitates the formation of fine particles by the phase inversion emulsification method. preferable. Particularly preferably, the acid value is 50 to
It is 150.

The reaction conditions for the resin (B) are usually 50 to 15
It is generally performed in a temperature range of 0 ° C. under a nitrogen atmosphere. Further, since the resin (B) becomes capsule type fine particles, it has a molecular weight at a sufficient level for the capsule wall, and usually has a weight average molecular weight of 5,000 to 200,000, preferably 10,000 to 150,000.

In carrying out the present invention, the above-mentioned resin (B) may be used in combination with other synthetic resins.

The neutralizing agent used in the present invention should be such that the above resin (B), that is, the anion type resin or the cation type resin exhibits hydrophilicity to the extent that it can be self-dispersed in an aqueous medium. For example, the compound is not limited to the kind, and a compound that easily generates a cation ion or an anion ion in an aqueous medium can be used.

Specific examples of effective neutralizing agents for anionic resins include, for example, sodium silicate, potassium silicate, sodium hydroxide, potassium hydroxide, lithium hydroxide, dibasic sodium phosphate, and tribasic phosphoric acid. sodium,
Inorganic alkali agents such as dibasic ammonium phosphate, tribasic ammonium phosphate, sodium metasilicate, sodium carbonate, and ammonia, mono-, di-, or trimethylamine, mono-, di-, or triethylamine, mono-, or diisopropylamine, n-butylamine, Organic amine compounds such as mono-, di- or triethanolamine, mono-, di- or triisopropanolamine, ethyleneimine, ethylenediimine and the like can be mentioned.

Specific examples of effective neutralizing agents for cationic resins include organic acids such as formic acid, acetic acid and propionic acid, and inorganic acids such as hydrochloric acid, sulfuric acid, sulfonic acid and phosphoric acid. .

In preparing the organic solvent solution used in the production method of the present invention, a known and commonly used coloring agent (A) can be used. Specifically, for example, carbon black,
Magnetic powder, nigrosine dye, aniline blue, calcoil blue, chrome yellow, ultramarine blue, DuPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, rose red iron oxide, C.I.
I. Pigment Red 122, C.I. I. Pigment Yellow 97, C.I. I. Pigment Blue 15, ferrosoferric oxide, ferric oxide, iron powder, zinc oxide, selenium, etc. can be used, and they can be used alone or in combination of two or more.

In the present invention, the obtained toner may be magnetic toner particles in which magnetic fine particles are dispersed in the resin (C). As the magnetic substance fine particles, any ferromagnetic substance that is normally used can be used.

Specific examples of the magnetic material include magnetic metals such as iron, cobalt and nickel, alloys of these, metal oxides such as cobalt-added iron oxide and chromium oxide, Mn / Zn ferrite, Ni / Zn ferrite and the like. Various kinds of ferrite,
In addition to magnetite, hematite, etc., the surface of these, silane coupling agent, aluminum coupling agent,
Powders such as those treated with a surface treatment agent such as a titanium coupling agent or those coated with a polymer can be used. In the present invention, a magnetic material is also included in the colorant (A).

As the colorant (A), it is preferable to select and use a colorant having a higher affinity for the resin (B) or (C) than that for water. As an example, a water-insoluble or poorly water-soluble colorant may be used.

As the organic solvent which can be used in preparing the organic solvent solvent solution, various aromatic hydrocarbons such as toluene, xylene or benzene;
Various alcohols such as methanol, ethanol, propanol or butanol; various ether alcohols such as cellosolve or carbitol; various ketones such as acetone, methyl ethyl ketone or methyl isobutyl ketone; ethyl acetate or butyl acetate , Various esters; or various ether esters such as butyl cellosolve acetate. Of course, these are the above-mentioned resins (B)
It can also be used when preparing itself.

The weight ratio of the solid contents of the colorant (A) and the resin (C) in the preparation of the organic solvent solution is not particularly limited, but when the total weight thereof is 100,
It is preferable that the colorant (A) is 3 to 15% by weight.

The non-volatile content of the organic solvent solution used for phase inversion emulsification is also not particularly limited, but is usually 10 to 70% by weight.

In the present invention, the above-mentioned neutralizing agent is added to an organic solvent solution of the resin (B) which can be self-dispersible in water by neutralization.
This can be achieved by preliminarily containing both in water used for phase inversion and phase inversion emulsification.

On the other hand, water containing a neutralizing agent is used in the present invention. As the water, for example, tap water, ion-exchanged water, distilled water or the like is used, but it is preferable to use water having an ion concentration as low as possible.

Water containing a neutralizing agent can be easily obtained by appropriately dissolving the neutralizing agent in water. The neutralizer here is
What was illustrated as an effective thing at the time of preparing the said organic solvent solution can be used similarly. At that time, the same neutralizing agent as that used in the preparation of the organic solvent solution may be used, or the same type of neutralizing agent having different polarities may be used.

In the present invention, the organic solvent solution contains
Phase inversion emulsification is performed by adding water containing the neutralizing agent. Usually, water containing the neutralizing agent is added while stirring the organic solvent solution. At this time, the temperatures of the organic solvent solution and the water containing the neutralizing agent may be the same or different, but it is generally preferable to carry out the phase inversion emulsification at the same temperature. The temperature at the phase inversion emulsification is more than 0 ° C and 80 ° C, especially 10
It is preferably carried out at ˜35 ° C.

In the phase inversion emulsification, water containing the neutralizing agent may be added all at once to the organic solvent solution, but it is usually preferable to add it dropwise.

The amount of the neutralizing agent used in the present invention depends on the resin (B).
Is added to the organic solvent solution of 1) in an amount less than the amount necessary to form the self-dispersing resin (C) having a predetermined particle size, and at least the insufficient amount is used on the water side.

At this time, the ratio of the amount of the neutralizing agent added to the organic solvent solution and the amount of the neutralizing agent added to water are not particularly limited, and are 95: 5 to 5:95, preferably 20:80 to 8.
It is divided at a weight ratio of 0:20.

According to the present invention, it was essential in the conventional manufacturing method. The strictness of the amount of neutralizing agent added can be greatly reduced. Specifically, a neutralizing agent in an amount less than the amount necessary to disperse water in a predetermined particle size is dissolved in the organic solvent solution side, and water in which an insufficient amount or more of the neutralizing agent is dissolved is added to By the phase emulsification, it becomes possible to granulate the toner particles to a desired particle size even with a relatively coarse (rough) quantitative division ratio. At that time, the granulation can be carried out by stopping the addition of the water containing the neutralizing agent at the time when the phase inversion point is reached and instead continuing the addition of the water containing no neutralizing agent. After reaching the phase point, the addition of water containing the remaining neutralizing agent may be continued as it is.

By carrying out phase inversion emulsification based on the above operation, a dispersion liquid of toner particles composed of the self-water-dispersible resin (C) containing the colorant (A) is obtained. The phase inversion point can also be visually observed, for example.

Toner particles can be obtained by removing the dispersion medium from this dispersion and drying the obtained product. The organic solvent and water may be removed simultaneously from the dispersion, but usually the organic solvent is removed first. When removing only the organic solvent from the dispersion liquid, for example, distillation is common, and vacuum distillation is suitable.

For the removal of the dispersion medium and the above-mentioned drying, any known method can be adopted. For example, the removal method of the dispersion medium includes decantation, filtration with a filter, etc., and the drying method includes, for example, Hot air drying, freeze drying, etc. are mentioned.

The toner particles thus obtained are spherical particles of the resin (C) containing the colorant (A).

In the above operation, after removing the organic solvent from the dispersion, a neutralizing agent having a polarity opposite to that of the neutralizing agent used for the phase inversion emulsification or water containing the same is added to carry out reverse neutralization. Alternatively, the resin (C) in the toner particles may be converted to the resin (B), water may be removed, and the resin may be dried.

The toner particles thus obtained are spherical particles of the resin (B) containing the colorant (A).

In the present invention, the toner particles are substantially spherical. The toner particles have a practical Wader sphericity (ratio of the diameter of a circle having an area equal to the projected area of the particle to the diameter of the smallest circle circumscribing the projected image of the particle) of 0.9.
It is preferably 5 to 1.00 and the average particle diameter is about 4 to 15 μm.

The toner particles obtained by the production method of the present invention may be provided with external additives such as silica fine powder, alumina fine powder and titanium fine powder, which are commonly used, on the surface thereof. .

At any stage of the production method of the present invention, waxes such as polyethylene wax, polypropylene wax and paraffin wax, metal soap, lubricants such as zinc stearate, cerium oxide and silicon carbide may be used, if necessary. It is also possible to use an auxiliary agent such as an abrasive, a copper phthalocyanine, perylene, quinacridone, an azo pigment, an azo metal-containing dye, a charge control agent such as an azochrome complex.

There are two-component developing method and one-component developing method for developing the electrostatic image formed on the surface of the photoreceptor in electrophotography, and the toner particles obtained in the present invention are two-component developing method. However, it can also be used in the one-component development method.

In the two-component developing system, the toner obtained in the present invention is mixed with a carrier to prepare a developer, and the friction causes the toner particles to be charged, and the toner particles adhere to the photosensitive member for development. .

In the magnetic brush developing method which is the mainstream of the two-component developing method, the toner obtained in the present invention is charged by friction with the carrier, and by forming a magnetic brush, only the toner is transferred to the photoreceptor. It adheres and is developed.

Any known carrier may be used as the carrier. Examples of the carrier include iron, nickel, copper, zinc,
Powders of metals such as cobalt, manganese, chromium, rare earths and alloys or oxides thereof, surface-treated glass, silica and the like can be used. Needless to say, a resin-coated carrier such as an acrylic resin-coated carrier, a fluororesin-coated carrier, or a silicone resin-coated carrier can also be used. As the carrier, for example, a carrier of about 20 to 200 microns is used.

When a two-component type electrostatic image developer is obtained from the toner obtained in the present invention and a carrier, for example, the toner is mixed at a ratio of 1 to 15 parts by weight of toner per 100 parts by weight of carrier. You can use it.

On the other hand, there is a magnetic one-component developing system using a magnetic toner mainly composed of magnetic powder as the colorant (A) or a non-magnetic one-component developing system consisting of only a non-magnetic toner. As a one-component developing method using non-magnetic toner, there is a contact-type non-magnetic one-component developing method in which a developing sleeve carrying a developer is brought into contact with a photosensitive drum having an electrostatic latent image for development.

The toner obtained in the present invention is passed through a space between a developing sleeve and a charging member pressed against the developing sleeve, and the toner is triboelectrically charged to form an electrostatic latent image formed on the surface of the photosensitive member. It can also be used in a contact-type non-magnetic one-component developing method for developing.

The developing sleeve material may be silicon rubber or a non-magnetic metal material such as stainless steel or aluminum, and the charging member may be flexible material such as stainless steel or rubber.

In the conventional production method in which the total amount of the neutralizing agent used for making the resin (B) self-dispersible in water is put in the organic solvent solution side, the toner produced in the phase inversion emulsification method is used. The most dominant factor that determines the particle size of particles is the amount of neutralizing agent added, and the amount of neutralizing agent added is 1%.
The amount of the toner added is required to be strict so that the diameter of the toner particles produced changes by about 10%.

Further, in the above conventional manufacturing method, when it is attempted to generate toner particles having a small particle size, it is indispensable to add a larger amount of the neutralizing agent to the organic solvent solution.
As a result, the solubility of the resin (C), that is, the anion type or cation type self-dispersing resin in water is improved, and the amount of the soluble resin in water used at the time of phase inversion is increased, resulting in a decrease in yield. Had. This phenomenon is 10
If you try to generate micron-sized toner particles,
It was especially remarkable.

Surprisingly, according to the production method of the present invention, a toner having a desired particle size equivalent to that of the above-mentioned conventional production method can be prepared with a smaller addition amount of the neutralizing agent. It has been found that the variation in particle size of the resulting toner with respect to quantitative variation can be significantly slowed down.

In summary, in order to produce spherical particles having a predetermined particle size in the phase inversion emulsification method, it is necessary to stably reproduce the phase inversion point at which a resin dissolved in an organic solvent is converted into water insoluble resin particles in water. How to get it is an important point. However, this phase inversion point changes due to the subtle difference in the balance between the amount of resin, the amount of neutralizing agent, the amount of organic solvent, and the amount of water in the system, and is greatly affected by the ambient temperature and stirring speed. . Therefore, in the conventional phase inversion emulsification method in which water is gradually added to the organic solvent solution of the resin (C) containing the neutralizing agent, this phase inversion point cannot be stabilized.

According to the present invention, the resin (B) is stably dissolved in the organic solvent and reaches the phase inversion point until the required minimum amount of the neutralizing agent is reached without being affected by the rate of adding water. At that moment, the resin is made into particles, and stable dispersed particles are generated in water.After that, even if water containing a neutralizing agent is continued to be added in an amount more than the required amount, the particles will not dissolve again and remain stable in water. It was confirmed that they could be dispersed in the medium.

[0067]

EXAMPLES The present invention will be described more specifically below by showing examples of the present invention. However, the invention is not limited to these examples.

(Example 1) 200 g of methyl ethyl ketone
Was placed in a reactor and heated to 80 ° C. Then, the mixture in the proportions shown below was added dropwise over about 2 hours. Meanwhile, the reaction was carried out in a nitrogen stream.

Methacrylic acid 45 g Styrene 207 g 2-Ethylhexyl acrylate 33 g Methyl methacrylate 15 g Perbutyl O 3 g Methylethylketone 12 g One hour after the addition of the above mixture was completed, 0.25 g of perbutyl O was additionally added, and then 2 hours later. 0.
25 g was added and the reaction was allowed to continue for 24 hours. After completion of the reaction, a styrene-based resin solution having a nonvolatile content of 54% and having anionic self-water dispersibility by neutralization was obtained. This resin had an acid value of 100 and a weight average molecular weight of 40,000.

200 g of this resin solution, 16 g of methyl ethyl ketone, 54 g of isopropyl alcohol and "MA
-100 "[Carbon Black manufactured by Mitsubishi Kasei Co., Ltd.]
5.6 g was mixed with "Eiger M-250VSE-EXJ" (Eiger product) for 1 hour to obtain a resin organic solvent solution in which a colorant was dispersed.

Resin organic solvent solution 5 in which this colorant is dispersed
0 g was charged into a four-necked flask, and triethylamine as a neutralizing agent was added with stirring to 22 mol% of the carboxyl groups of the resin.
A considerable amount was added and dissolved, and a colorant-dispersed organic solvent solution of the neutralizing agent and the resin was obtained (this is referred to as Solution 1).

Separately, triethylamine was uniformly dissolved in 150 g of distilled water in an amount corresponding to 8 mol% based on the carboxyl groups of the resin to prepare an aqueous solution of triethylamine, which was prepared in a dropping funnel. Under stirring, a triethylamine aqueous solution was dropped into the solution 1 at a rate of 10 cc / min to carry out phase inversion emulsification.

Phase inversion emulsification occurred when the addition of the triethylamine aqueous solution was started and the total amount of triethylamine reached 24.4 mol% of the carboxyl groups of the resin. Then, the triethylamine aqueous solution was replaced with simple distilled water, and the solution was added dropwise into the system at the same dropping rate. The total amount of mere distilled water used here is
The amount of triethylamine aqueous solution remaining in the dropping funnel at the time of phase inversion emulsification was adjusted to the same amount.

The organic solvent was removed by vacuum distillation to obtain a pH of 6
A 0.01N aqueous hydrochloric acid solution was added until the mixture became, and the mixture was filtered and dried with a freeze dryer to obtain microtoner powder particles. When the weight of the obtained powder particles was measured, the yield was 96.8%, and the amount of resin eluted without being granulated during phase inversion emulsification was 3.2%.

When the obtained powder particles were observed by SEM, it was confirmed that they were substantially spherical toner particles,
The volume average particle diameter measured by a Coulter counter was 8.9 microns.

(Example 2) Even after the phase inversion emulsification, the whole amount of the triethylamine aqueous solution remaining in the dropping funnel was added to the solution 1 at the same rate without replacing it with mere distilled water.
The same operation as in the above example was carried out except that the solution was added dropwise.

The yield, the amount of eluted resin, the shape of the obtained toner particles, and the particle size thereof were almost the same as those in Example 1.

(Comparative Example 1) The toner was granulated by the conventional phase inversion emulsification method in which the amount of the neutralizing agent was adjusted so that the same particle size as in Example 1 was obtained and the total amount of the neutralizing agent was added to the resin solution. . It was confirmed that when 26 mol% of triethylamine of the carboxyl group of the resin was used, the resin (B) became the resin (C) and phase inversion emulsification occurred.

Triethylamine as a neutralizing agent was added and dissolved in 50 g of the colorant dispersion solution used in Example 1 in an amount of 26 mol% of the carboxyl groups of the resin. Under stirring, 150 g of simple distilled water containing no neutralizing agent was added dropwise thereto at a rate of 10 cc / min to carry out phase inversion emulsification.

The organic solvent was removed by vacuum distillation to obtain a pH of 6
A 0.01N aqueous hydrochloric acid solution was added until the mixture became, and the mixture was filtered and dried with a freeze dryer to obtain microtoner powder particles. The average particle diameter was 8.5 microns, and although micro toner having the same size as in Example 1 was obtained, the weight of the obtained powder particles was measured and the yield was 89.7%.
The amount of the self-water-dispersible resin eluted without being formed into particles during the phase inversion emulsification was 10.3%, which was a large material loss. The total amount of triethylamine used was 1.6 mol% higher than that of Example 1.

The dry microtoner of Example 2 was mixed and stirred at a ratio of 4 parts with 100 parts of a ferrite carrier having an average particle size of 65 μm to obtain a non-magnetic two-component developer. When the charge amount was measured by the blow-off method, a value of -37 μC / g was shown.

When a copy test was conducted on this developer with a commercially available electronic copying machine, a clear image with high density was obtained.

(Examples 3 to 5) In Example 2, the total amount of triethylamine used was fixed at 30.0 mol% of the carboxyl groups of the resin, and the addition amount ratio to the colorant dispersion solution and the addition amount to water were fixed. Phase inversion emulsification was performed by changing the ratio of the added amount. In Example 3, the addition ratio of triethylamine was 20 mol% equivalent amount in the colorant dispersion solution-10 mol% equivalent amount in the triethylamine aqueous solution, and 18 mol% equivalent amount-12 mol% equivalent amount. Example 4) and 16 mol% equivalent amount-14 mol% equivalent amount (Example 5) were carried out in the same manner as in Example 2. The relationship between the average particle diameter of the toner particles produced under each condition and the amount of triethylamine added to the resin organic solvent solution is shown in FIG.

Comparative Examples 2 to 4 As in Comparative Example 1, neutralizing agent triethylamine was added only to the resin solution, and water containing no neutralizing agent was added to carry out phase inversion emulsification. At that time, the amount of triethylamine added to the colorant dispersion solution was changed by 1 mol%. The case where the amount of triethylamine is 25 mol% is Comparative Example 2, the case of 24 mol% is Comparative Example 3, and the case of 23 mol% is Comparative Example 4.

In Examples 1 to 5 and Comparative Examples 1 to 4,
The average particle size of the toner particles generated under each condition,
The relationship with the amount of triethylamine added to the resin organic solvent solution is shown in FIG. As is clear from the figure, in the conventional method of the comparative example, the particle size of the microtoner particles produced may vary greatly with a slight change in the amount of addition of the neutralizing agent, as compared with the example. Recognize.

[0086]

INDUSTRIAL APPLICABILITY According to the present invention, in the method for producing a dry toner by the phase inversion emulsification wet process, the phase inversion emulsification is carried out by adding a neutralizing agent to both the resin dispersion and water used for the phase inversion.
It is possible to control the particle size of generated toner easily and to reduce the dissolution loss of the self-water-dispersible resin, which is the raw material, in water. Improve.

[Brief description of drawings]

FIG. 1 is a diagram showing a correlation between the amount of triethylamine and the particle size of produced particles.

Claims (3)

[Claims] 1. A resin (B) in which a colorant (A) is dispersed and which can be self-water dispersible by neutralization, and an amount less than the amount necessary to disperse the resin (B) in water with a predetermined particle size. Water containing at least the insufficient amount of the neutralizing agent required to disperse the resin (B) into a predetermined particle size in water is added to an organic solvent solution in which a solvating agent is dissolved, and phase inversion emulsification is performed to obtain a colorant. A toner comprising a self-water-dispersible resin (C) containing a colorant, which is obtained by obtaining a toner particle dispersion liquid comprising the self-water-dispersible resin (C) encapsulating (A), removing the dispersion medium and drying. Method for producing particles. 2. A resin (B) in which a colorant (A) is dispersed and which can be self-water dispersible by neutralization, and an amount less than the amount necessary to disperse the resin (B) in water with a predetermined particle size. Water containing an insufficient amount of a neutralizing agent required to disperse at least the resin (B) in water to a predetermined particle size is added to an organic solvent solution in which a solvating agent is dissolved, and phase inversion emulsification is performed to obtain a colorant. After obtaining a toner particle dispersion liquid comprising a self-water-dispersible resin (C) encapsulating (A), removing the organic solvent, and reverse neutralizing the resin (C) to convert it into a resin (B), A resin (B) that removes water and is dried and becomes self-dispersible by neutralization containing a colorant
And a method for producing toner particles. 3. The resin (B) is a resin containing a carboxyl group and capable of becoming self-water dispersible by neutralization with a base. The resin (B) is a self-water dispersible resin (C) having a predetermined particle size. ), At least 20% of an organic solvent solution of a partially neutralized product neutralized with a 20-80% equivalent amount of a base necessary for
The production method according to claim 1 or 2, wherein phase inversion emulsification is carried out with water containing a considerable amount of a base in advance.