JPH01303450A - Production of toner for developing electrostatic charge image - Google Patents

Abstract

PURPOSE:To efficiently obtain the toner having excellent fixability, durability and flowability by subjecting a polymerizable compsn. consisting of a polymerizable monomer and coloring agent, etc., to suspension polymn., immersing the compsn. in a specific org. solvent and stirring the solvent, then taking the polymerizable product out of the solvent and drying the same. CONSTITUTION:The polymerizable compsn. consisting of the polymerizable monomer and additives such as coloring agent is charged into the aq. solvent and the resultant polymerizable product is immersed in the org. solvent which dissolves the monomer component but doe not dissolve the polymer component and has high volatility. After the solvent is stirred, the polymerizable product is taken out of the solvent and is dried. The polymerizable monomer is a styrene monomer, acryl monomer, etc., and the coloring agent is usable by incorporating a coloring pigment into the monomer. The coloring agent and the monomer are used at 1:100-20:100 ratio by weight. Polyvinyl alcohol, etc., are used as the dispersion stabilizer to stabilize the polymerizable compsn. as oil drop particles by suspending the same into a water medium. The toner having the excellent flowability, moisture resistance and durability is produced in a short period of time with high productivity in this way.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a toner for developing electrostatic images used in electrophotography, electrostatic printing, etc. It is an object of the present invention to provide a method for manufacturing toner in an extremely short period of time.

(Prior Art) In the fields of electrophotography and electrostatic printing, toners are used for the purpose of visualizing electrostatic images. This toner is made by blending other ingredients such as a colorant and a charge control agent into a resin medium, and the particle size is within a certain range, for example, 5 to 30 μm.
The resin medium is a resin with the desired electrodetection properties and binding properties, such as a styrene resin, and the colorant is carbon black or an organic or inorganic resin. Coloring pigments are used, and as the charge control agent, oil-soluble dyes, metal-containing complex salt dyes, etc. are used.

The most typical manufacturing method for electrophotographic toners consists of the steps of melt-kneading the aforementioned resin medium and colorant, and cooling and pulverizing this kneaded composition to obtain particles within a certain range of particle sizes. However, the yield of toner obtained by this pulverization and classification is low, and these operations require a large amount of equipment.
This makes the manufacturing cost of toner extremely high.

Furthermore, although the toner obtained by the pulverization method can achieve a certain level of performance, it has been recognized that the toner has an irregular shape, generally has poor fluidity, and is prone to blocking in the developing device. In addition, irregularly shaped toner particles have large differences in the amount of charge accumulated in individual particles, which results in different triboelectric charging properties and poor fluidity, making it difficult for the development characteristics to remain constant as the development process progresses. It has also been recognized that there are problems in that the image does not sag, resulting in image deterioration.

Japanese Patent Publication No. 36-10231 discloses a method for solving the above-mentioned problems in the pulverization method toner and its production and for producing spherical toner all at once during the polymerization process of the fixing resin.
Special Publication No. 51-14895, Special Publication No. 53-1773
Publication No. 5, Special Publication No. 53-17736 and Special Publication No. 4
As described in Japanese Patent No. 7-51830, a method for producing toner using a polymerization method has been proposed.

These methods are based on the so-called suspension polymerization method, in which a polymerizable composition, which is a mixture of a polymerizable monomer, a toner characteristic imparting agent such as a colorant, and a polymerization initiator, is placed in an aqueous solution containing a dispersion stabilizer. The toner is directly produced by suspending the suspension by high-speed shearing and stirring and polymerizing the suspension. This method has the advantage that the toner particles produced are spherical, have excellent fluidity, have uniform charging characteristics, and have a simple manufacturing process and low cost.

(Problems to be Solved by the Invention and Background of the Invention) However, in the method of directly producing toner by polymerization, many types of toner characteristic imparting agents such as colorants and charge control agents are added and mixed. The resulting polymerizable composition is then subjected to a polymerization reaction, and many of these toner characteristic imparting agents inhibit the polymerization reaction. In particular, carbon black, which is a common coloring agent for black toners, has a strong polymerization inhibiting effect and retards the polymerization reaction, so that unreacted monomers may remain in the resulting polymer particles. If polymer particles in which monomers remain in the particles are used as toners, they will have poor impact resistance in the developing device, and unreacted monomers will be exposed, reducing the fluidity of the toner and resulting in a higher yield. There have been problems in that it causes fog in the copied images that are produced, causing image deterioration, and that the development characteristics are significantly degraded, especially at high temperatures and high humidity.

In order to solve the above-mentioned problems, it is possible to increase the polymerization rate by using a large amount of polymerization initiator, complete the polymerization reaction, and reduce the amount of unreacted residual monomer, but this suspension polymerization In the toner manufacturing method, it is necessary to obtain toner-sized polymer particles all at once through a polymerization reaction, and the resulting polymer must have a molecular weight distribution suitable for the fixing properties of a toner. Using a large amount of the toner causes the polymer to have a low molecular weight, resulting in a toner with poor fixing properties and durability.

In addition, in recent years, a wide variety of copying machines have been developed and used, from high-speed machines to low-speed machines, and the documents to be copied are not just office documents, but also a wide variety of documents such as photographs and pamphlets. As manuscripts have come to be used, the toner used is also produced for each model or color, so there is a need for an efficient manufacturing method in a shorter time and at lower cost.

Therefore, the present invention has been made to solve the above-mentioned problems and meet the above-mentioned demands.An object of the present invention is to eliminate residual unreacted monomers without using a large amount of polymerization initiator. It is an object of the present invention to provide a method for manufacturing toner that can significantly reduce the amount of toner.

Another object of the present invention is to provide a method for efficiently producing a toner that can significantly shorten the production time and has excellent fixing properties, durability, and fluidity.

(Means for solving the problem) A polymerizable composition consisting of a polymerizable monomer and additives such as a coloring agent is introduced into an aqueous medium to perform suspension polymerization, and the resulting polymerization product is monomerized. After immersing and stirring in a highly volatile organic solvent that dissolves polymer components but not polymer components,
The object of the present invention is achieved by removing the polymerization product from the solvent and drying it.

(Function) The present invention has been made based on the findings described below.

In order to prevent the polymer particles produced by Qi polymerization from exhibiting good fixing properties, if the amount of polymerization initiator is used so that the polymer component has a favorable molecular weight, the OA curve in Figure 1 As can be seen, the polymerization rate exceeds 90% in approximately 2 to 3 hours, and the reaction rate decreases significantly after the polymerization reaction is completed to some extent.

Polymer particles whose polymerization rate has reached 90% or more have a molecular weight distribution that allows the polymer components to exhibit good fixing properties, and the polymer particles that have reached a polymerization rate of 90% or more are unreacted. This process is carried out continuously in order to reduce the monomer content as much as possible, and when the polymerization rate of the polymerizable composition reaches the above-mentioned stage, unreacted substances in the produced polymer particles are removed. If the monomer can be quickly removed from the particles, the polymerization reaction can be completed when the polymerization rate reaches 90% or more, which can significantly shorten production time and avoid adding more polymerization initiator than necessary. Since there is no need for the toner, toner can be manufactured efficiently and in a short time.

Therefore, the present inventors focused on the fact that when the polymerization rate mentioned above reaches 90% or more, the polymer particles exist in a state where the unreacted monomer swells the polymer component. When polymer particles are immersed and stirred in a highly volatile organic solvent that is compatible with the monomer and does not dissolve the polymer components, unreacted monomers are removed from the polymer particles. It can be extracted and removed effectively, and has good fixing properties when dried after filtration.
They have discovered that a toner with excellent fluidity and environmental resistance can be obtained.

The present invention will be explained in detail below.

The polymer particles are produced by a toner manufacturing method using a known polymerization method.

Examples of toner characteristic imparting agents such as polymerizable monomers and colorants constituting the polymerizable composition include those described below.

The polymerizable monomer is radically polymerizable,
In addition, one type of monomer or a combination of two or more types of monomers whose produced polymer has the fixing properties and electrodetection properties required for the toner is used.

Suitable examples of these monomers include vinyl aromatic monomers, acrylic monomers, vinyl ester monomers, vinyl ether monomers, diolefin monomers, monoolefin monomers, etc. be.

The vinyl aromatic monomer has the following formula: In the formula, R3 is a hydrogen atom, a lower alkyl group, or a halogen atom, and R2 is a hydrogen atom, a lower alkyl group, a halogen atom, an alkoxy group, a nitro group, or a vinyl group. , vinyl aromatic hydrocarbons such as styrene, α-methylstyrene, vinyltoluene, α-chlorostyrene, 0-
Examples include 1m-1p-chlorostyrene, p-ethylstyrene, and divinylbenzene alone or in combination of two or more, and other monomers mentioned above include the following.

Acrylic monomers, such as methyl acrylate, of the formula, where R3 is a hydrogen atom or a lower alkyl group R1 is a hydrogen atom, a hydrocarbon group having up to 12 carbon atoms, a hydroxyalkyl group, or a vinyl ester group; Ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, hexyl methacrylate,
2-ethylhexyl methacrylate, ethyl β-hydroxyacrylate, propyl T-hydroxyacrylate,
σ-hydroxybutyl acrylate, β-hydroxyethyl methacrylate, ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, etc.

A vinyl ester of the formula, O in which R6 is a hydrogen atom or a lower alkyl group, such as vinyl formate, vinyl acetate, vinyl propionate, and the like.

Vinyl ethers of the formula, wherein R6 is a monovalent hydrocarbon group having up to 12 carbon atoms, such as vinyl-n-butyl ether, vinyl phenyl ether, vinyl cyclohexacyl ether, etc.

Diolefins, especially butadiene, isoprene, and chloroprenes of the formula, wherein each of R7, Re, and Rq is a hydrogen atom, a lower alkyl group, or a halogen atom.

Monoolefins, especially ethylene, propylene, isobutylene, butene-1, of the formula, l0C1(2-tongue-R,, (6) where each of R3° and RI1 is a hydrogen atom or a lower alkyl group) , pentene-1,4-methylpentene-1, etc.

Among the above monomers, preferred monomers include styrenic monomers,
Acrylic monomers, etc.

As the coloring agent used in the present invention, various pigments and dyes (hereinafter simply referred to as coloring pigments) described below can be incorporated into the monomer.

Black pigments carbon black, acetylene black, lamp black, aniline black.

Yellow pigments yellow lead, zinc yellow, cadmium yellow, yellow iron oxide, mineral first yellow, nickel titanium yellow, Fujiburus yellow, Teftol yellow S, Hansa yellow 10G, benzidine yellow G1 quinoline yellow lake, permanent yellow NGG, tartrazine rake.

Color-loss pigments red yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange, palkan orange, indanthrene brilliant orange RK, benzidine orange G1 indanthrene brilliant orange GK.

Red pigment red pigment, cadmium red, red lead, cadmium sulfide, permanent orange 4R, resol red,
Pyrazolone Red, Watching Red Calcium Salt,
Lake Red D, Brilliant Carmine 6B, Eosin Lake, Rhodamine Lake B, Alizarin Lake, Brilliant Carmine 3B.

Purple pigment Manganese Purple, Fast Violet B, Methyl Violet Lake.

Blue pigments navy blue, cobalt blue, alkali blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partially chlorinated product, first sky blue, indance blue B
C.

Green pigment chrome green, chromium oxide, pigment green B,
Malachite Green Lake, Final Yellow Green G0 White pigment zinc white, titanium oxide, antimony white, zinc sulfide.

Extender pigments Palite powder, barium carbonate, clay, silica, white carbon, talc, aluminum white.

As a magnetic material pigment, for example, triiron tetroxide (Fe: +0
4), iron sesquioxide (y -FezO:+), zinc iron oxide (ZnFe2O4), iron yttrium oxide (Y:
+Fe50+ z), cadmium oxide (GdJesO+
z), iron copper oxide (CuFezO4), iron oxide complex (Pb
Fe+□0.9), neodymium iron oxide (NdFe03
), barium iron oxide (BaFe, zO+q), magnesium oxide (MgFezOa), iron manganese oxide (
MnFe204), lanthanum iron oxide (LaFeOz)
, iron powder (Fe), cobalt powder (Co), nickel powder (
Although Ni) and the like are known, any of these known fine powders of magnetic materials can be used in the present invention.

The ratio of the monomers to the colorant can vary considerably; however, - i.
A weight ratio of from 32100 to 10:100 can be used.

In order to improve the charging characteristics of the toner, examples of charge control agents include nigrosine, monoadz dye, zinc hexadecyl succinate, alkyl esters or alkylamides of naphthoic acid, nitrofumic acid, N, N'
-TeI-Lamethyldiaminehensiphenon, N,N"-
Strongly polar substances called charge control agents are used in this field, such as tetramethylhenzidine, triazine, and metal salicylate complexes. These charge control agents are polymerizable monomers with 10
n, Of to 10 parts by weight per 0 parts by weight are used.

Further, in order to improve fixing properties and prevent offset, wax may be added and mixed into the above monomer. Examples include various waxes such as low molecular weight polypropylene, low molecular weight polyethylene, and paraffin wax. The average molecular weight of the above wax is 2000.
It is preferably from 15,000 to 15,000, particularly from 3,000 to 10,000.

These waxes are generally preferably used in an amount of 1 to 5 parts by weight, particularly 1.5 to 3 parts by weight, per 100 parts by weight of the polymerizable monomer.

The dispersion stabilizer that suspends the polymerizable composition consisting of the various components mentioned above in an aqueous medium and stabilizes it as oil droplet particles includes water-soluble polymers such as polyvinyl alcohol and methylcellulose, and nonionic or ionic interfaces. Activator, calcium sulfate, calcium phosphate, magnesium carbonate,
Fine powders of sparingly water-soluble inorganic salts such as barium carbonate, calcium carbonate, aluminum hydroxide, etc. are used.

The above-mentioned dispersion stabilizer is preferably added in an amount of 0.1 to 50% by weight, particularly 1 to 10% by weight per bottle.

The particle size of the suspended oil droplets is between 5 μm and 30 μm, especially 8 μm.
It is appropriate to adjust the thickness to 12 μm. Examples of polymerization initiators include azo compounds such as azobisisobutyronitrile, and peroxides such as cumene hydroperoxide, t-butyl hydroperoxide, dicumyl peroxide, di-butyl peroxide, benzoyl peroxide, and lauroyl peroxide. Oil-soluble initiators such as In addition, combinations with ionizing radiation such as γ-rays and accelerated electron beams, and various sensitizers are also used.

The amount of the polymerization initiator such as an azo compound or peroxide may be a so-called catalyst appropriate amount, and is generally preferably used in an amount of 0.1 to 10% by weight based on the monomers charged.

The polymerization reaction temperature may be a known temperature, and -C is 40 to 10
A temperature of 0°C is sufficient. For this purpose, the reaction system may be stirred at a gentle pace so that a homogeneous reaction occurs as a whole.Also, in order to prevent the polymerization from being inhibited by oxygen, the reaction system may be replaced with an inert gas such as nitrogen to carry out the polymerization. You can. and,
When the polymer particles obtained reach a polymerization rate of 90%,
Weight average molecular weight generally ranges from 1oooooo to 500,000
, preferably in the range of 200,000 to 400,000, and the softening point is generally 50 to 200°C, preferably 7
The resin component has a temperature of 0 to 170°C.

The polymer particles obtained by the above polymerization reaction have a polymerization rate of 90
%, the polymer particles are collected, immersed in a highly volatile solvent that is compatible with the monomer but does not dissolve the polymer components, and subjected to a stirring operation. conduct.

Preferred solvents are conveniently selected depending on the resin components of the resin particles to be produced and the polymerizable monomer used, and include methanol, ethanol, propanol, butanol, isobutanol, tert-butanol, hexanol, octatool, etc. alcohols, n-hexane,
Aliphatic hydrocarbons such as penkune, heptane, octane, isooctane, decane, 2.2-dimethylbutane, cyclohexane, aromatic hydrocarbons such as benzene, toluene, xylene, dichloromethane, dichloroethane, carbon tetrachloride, chlorobenzene, etc. Halogenated hydrocarbons, dioxane, dimethyl ether, diethyl ether, tetrahydrofuran, ethylene glycol monomethyl ether,
Ethers such as ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, and ethylene glycol diethyl ether, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, acetonitrile,
Various organic solvents are used, such as formamide, dimethylformamide, and dimethylformamide.

The above organic solvents may be used alone, but depending on the toner resin, two or more types of organic solvents may be used as a mixed solvent.

In addition, the stirring speed may generally be a gentle stirring operation of about 30 to 200 rpm, and the processing time may be 0.
．． In about 0.1 to 5 hours, the remaining monomer is sufficiently extracted from the particles. Further, at this time, ultrasonic waves may be irradiated to impact the particles, making the extraction operation more efficient. The frequency of the ultrasonic waves to be irradiated is generally 5 to 50 kHz, and the irradiation amount is generally 0.01 to 10 (w).
/l/HR), especially 0. 1 to 5 (w/l/HR) is preferred.

The immersed and stirred polymer particles are then filtered and dried to form a toner. The toner thus obtained has almost no residual monomer and has excellent fixing properties, environmental resistance, and fluidity.

Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

(Example) Styrene 80 parts 2-ethylhexyl methacrylate 20 parts Grafted carbon black 5 parts Charge control agent (Bontron 5-34, manufactured by Orient Chemical Co., Ltd.)
1 part by weight divinylhenzen 0.5 parts ffi These polymerization compositions were sufficiently dispersed in a ball mill, and then a polymerization initiator (2,2'-azobis) was added.

It was prepared by dissolving 2 parts by weight of 2.4-dimethylvaleronitrile.

This composition was poured into 400 parts by weight of water in which 12 parts by weight of tertiary calcium phosphate was finely dispersed, and stirred and dispersed for 15 minutes at 6000 rpm using a TK Bomo mixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). After this, under a nitrogen stream, at 80°C for 3
A time polymerization reaction was performed.

The styrene monomer and acrylic monomer remaining in the polymer particles at this point were analyzed by gas chromatography (GC-
9) (manufactured by Takashi Seisakusho) and the polymerization conversion rate was 95%.The toner was filtered and washed with water for 2 times.
The resulting cake was dispersed in 400 parts by weight of methanol, stirred for 30 minutes, filtered, and dried.

When the residual upper monomer in the obtained toner was quantified in the same manner as described above, almost no peaks of either styrene monomer or acrylic monomer were detected. was generated.

Using this obtained toner, an electrophotographic copying machine, DC-1
11C (manufactured by Sanda Kogyo Co., Ltd.) was used to conduct an image formation experiment, and a printing durability test was also conducted. The results are shown in Table-1. As can be seen from the table, the moisture resistance, fixing properties, and durability were all good.

(Comparative Example 1) Polymerization reaction was carried out for 3 hours in the same manner as in Example, and the polymerization conversion rate was 9.
Polymer particles at 5% were obtained. Then, the obtained particles were used as a toner as they were without being immersed in methanol or stirred, and image formation experiments and printing durability tests were conducted in the same manner as in the examples. The results are shown in Table-1. As can be seen from the table, both moisture resistance and rigidity resistance were poor, and a bad odor was emitted during fixing.

(Comparative Example 2) In order to complete the polymerization reaction in 3 hours, a polymerization initiator (2
, 2'-azobis, 2,4-dimethylvaleronitrile)
A toner was synthesized by adding 5 parts by weight and carrying out a polymerization reaction for 3 hours in the same manner as in Example 1. The polymerization conversion rate of this toner was measured in the same manner as in Example 1, and the polymerization conversion rate reached 100% as shown in 1 [D, B in the figure. There was no residual monomer present. Furthermore, an image production experiment and a printing durability test were conducted using this toner. The results are shown in Table-1. As is clear from the table, although the toner had good moisture resistance, offset occurred during fixing, and the fixing roller was stained with toner, making it impossible to carry out long printing experiments.

(Hereinafter, blank space) (Effects of the invention) According to the present invention, it is possible to manufacture toner with excellent fluidity, corrosion resistance, and durability with high productivity in a short time, and toner manufacturing costs can be reduced. This makes it possible to suitably cope with the production of other types of toner in small quantities.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the relationship between polymerization time and polymerization conversion rate. A is the relationship between time and polymerization conversion rate when a preferable amount of polymerization initiator is added to obtain a polymer component exhibiting excellent fixing properties. B completed the polymerization reaction in 3 hours (polymerization conversion rate 100%)
Relationship between time and polymerization conversion rate when adding the amount of polymerization initiator necessary to achieve the desired result. Patent thA et al. 5a type 8 no 11th sword day 1 period (layer,)

Claims (1)

[Claims] A polymerizable composition consisting of a polymerizable monomer and additives such as a coloring agent is placed in an aqueous medium to perform suspension polymerization, and the resulting polymerization product is dissolved in the monomer components but not in the polymer. After immersing the components in a highly volatile organic solvent that does not dissolve them and stirring,
A method for producing a toner for developing an electrostatic image, which comprises taking out a polymerization product from the solvent and drying it.