JPH03136065A - Toner for developing electrostatic charge image and production thereof - Google Patents

Abstract

PURPOSE:To obtain a toner having superior fixability and anti-offsetting property by suspension-polymerizing a polymerizable monomer contg. a colorant and an electrostatic charge controlling agent in the presence of a macromonomer soluble in the polymerizable monomer. CONSTITUTION:A polymerizable monomer contg. a colorant and an electrostatic charge controlling agent is suspension-polymerized in the presence of a macromonomer to obtain a toner having 3-15mum number average particle size and 15-45% coefft. (y) of variation of particle size defined by equation I, wherein s is the standard deviation (mum) of particle size-number distribution and x is number average particle size (mum). The macromonomer used is preferably a macromonomer practically soluble in the polymerizable monomer but practically insoluble in water. The resulting toner for developing an electrostatic charge image has superior anti-offsetting property and fixability.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an electrostatic image development method used for developing electrostatic images formed in electrophotography, electrostatic printing, electrostatic recording, etc. The present invention relates to a toner for use in commercial use, and a method for manufacturing the same.

[Prior Art and Problems to be Solved by the Invention] Generally, in electrophotography, an electrostatic image formed on a photoreceptor is generated by toner, which is a colored fine powder in which a coloring agent is dispersed in a binder resin. This toner image is visualized, and then this toner image is transferred onto a transfer paper and fixed to obtain a copy or the like. There are many known methods for fixing this toner image, among them contact using a heating roller constant fixing device and heat fixing method. Specifically, the toner image is fixed between a pair of rollers consisting of a heating roller and a pressure roller. A heat roll fixing method in which paper is inserted and heat-pressed and fixed is widely used because of its advantages such as high thermal efficiency and high-speed fixing.

However, in the heat roll fixing method, the toner comes into contact with the roller surface and is melted to perform fixing.
A phenomenon in which toner adheres to the roller surface, a so-called offset phenomenon, is likely to occur. This offset phenomenon occurs when the viscoelasticity of the toner melted by heating is not appropriate. More specifically, for good fixing, it is important to have a balance between low molecular weight components that contribute to fixing properties and high molecular weight components that contribute to anti-offset properties, and if the low molecular weight components are insufficient, poor fixing will occur. An offset phenomenon occurs when there is a shortage of high molecular weight components.

Although many methods have been proposed to solve these problems, it is desirable to solve these problems by improving the toner itself.

For example, a method is known in which a binder resin is crosslinked using a crosslinking agent, as described in Japanese Patent Publication No. 51-23354. However, in this method, if the degree of crosslinking of the binder resin is increased in order to obtain sufficient anti-offset property, the softening point becomes high and fixing performance deteriorates.

Furthermore, as described in Japanese Patent Publication No. 52-3304, it has been reported that offset resistance is improved by incorporating a mold release agent such as a low molecular weight polyolefin wax such as low molecular weight polypropylene. In order to obtain a sufficient effect in this method, it is necessary to increase the content of the wax considerably, and as a result, the fluidity of the toner decreases, which adversely affects the developability, transferability, etc. In addition, it has drawbacks such as causing filming on the photoreceptor.

Furthermore, Japanese Patent Publication No. 64-10821, Japanese Patent Publication No. 64-1
As described in Publication No. 0822, by containing a reactive prepolymer such as polybutadiene and a crosslinking agent and a low molecular weight polyolefin, offset resistance is improved due to the crosslinking effect of the reactive prepolymer and crosslinking agent. It has been reported that fixing properties are also improved by low molecular weight components such as low molecular weight polyolefins and unreacted prepolymers. However, even in this method, the offset resistance is improved by crosslinking the binder resin, and as mentioned above, the softening point increases and the fixing performance decreases.
Although fixing properties are improved by low molecular weight components such as low molecular weight polyolefins and unreacted prepolymers, they only compensate for this.

The present invention has been made based on the above circumstances, and an object of the present invention is to provide a toner for developing electrostatic images that has excellent anti-offset properties and also has excellent fixing properties.

Another object of the present invention is to provide a toner for developing electrostatic images having excellent fluidity.

[Means to solve the problem]

As a result of intensive studies to achieve the above object, the present inventors have found that a polymerizable monomer containing a colorant and a charge control agent is suspended in the presence of a macromonomer soluble in the polymerizable monomer. It has been discovered that a toner with excellent fixing properties, anti-offset properties, and fluidity can be obtained by carrying out turbidity polymerization, and the present invention has been completed.

That is, the present invention provides a polymerizable monomer containing a colorant and a charge control agent, which is obtained by suspension polymerization in the presence of a macromonomer, and has a number average particle diameter of 3 to 15ρ, and has the following formula: Particle size variation coefficient y defined as y = (s/x) The present invention provides a toner for developing an electrostatic image that satisfies the above requirements, and the present invention also provides a method for producing a toner for developing an electrostatic image by suspension polymerization, in which a colorant, a charge control agent, and a macromonomer are added. A step of dispersing the polymerizable monomer in a wet media type pulverizer, and a step of dispersing the polymerizable monomer mixture in an aqueous medium using a continuous disperser using cavitation, swirling flow or turbulence. The present invention provides a method for producing a toner for developing an electrostatic image, comprising a step of shearing and dividing the toner to a particle size suitable for the toner.

The reason why the excellent effects are obtained in the toner of the present invention is considered to be that since polymerization is performed in the presence of the macromonomer, a polymer in which the macromonomer is grafted onto the monomer unit is generated. That is, in detail, entanglement of macromonomer units of tj[, so-called physical crosslinking, occurs between polymer molecules, and apparently a high molecular weight portion effective for anti-offset properties is generated.

Furthermore, this crosslinking is different from chemical crosslinking using a crosslinking agent, etc., and the entanglement is dissolved due to thermal movement of polymer molecules, and in this case, the proportion of relatively low molecular weight moieties that are effective for fixing properties is considerably increased. It is thought that fixing properties are improved.

As described above, in the present invention, since these phenomena occur in a timely manner during toner fixing, it is considered that excellent offset resistance and fixing properties are exhibited. Further, in the toner of the present invention, a release agent such as a low molecular weight polyolefin may be contained for the purpose of promoting these effects.

The method for manufacturing the toner of the present invention will be described below with specific examples.

In the present invention, first, a colorant such as carbon black, a charge control agent, macromonomer 1, and other necessary toner property improvers are uniformly mixed and dispersed in a polymerizable monomer using a wet media type pulverizer. This is added to an aqueous phase in which a dispersion stabilizer such as calcium phosphate and a dispersion stabilizing agent such as an anionic surfactant are uniformly dissolved. A continuous disperser using flow or turbulence is used to shear and break up the oil phase droplets to a particle size suitable for the toner. The weight ratio of the oil phase to the aqueous phase is arbitrarily set within the range of 1:1 to 1:20.

The dispersion liquid in which the oil phase is uniformly dispersed in the water phase is transferred to a polymerization reaction tank equipped with a stirring device, a condenser, a thermometer, and a nitrogen introduction tube, and the temperature is raised to the temperature at which the polymerization initiator decomposes (50 to 90 °C). Then, polymerization is carried out under a nitrogen atmosphere. After the polymerization is completed, hydrochloric acid is added to eliminate the phosphate salt, the aqueous phase is removed by filtration, and after washing with water, water is removed by means such as spray drying or vacuum drying to obtain the toner of the present invention.

Here, the macromonomer in the present invention has a vinyl polymerizable functional group at one end of the molecular chain and has a number average molecular weight of 5.
It means an oligomer or polymer having a relatively low molecular weight of about OOOO.

Further, the macromonomer used in the present invention is preferably a macromonomer that is substantially soluble in the polymerizable monomer and substantially insoluble in water, and specifically,
Polymers such as styrene, styrene substituted products, (meth)acrylic acid esters, (meth)acrylonitrile, copolymers of two or more of these, and macromonomers having a polysiloxane skeleton can be mentioned. If the macromonomer is insoluble in the polymerizable monomer or soluble in water, grafting is difficult to occur and this is not preferable because it may cause unstable polymerization.

Furthermore, the number average molecular weight of the macromonomer that acts effectively in the present invention is from 500 to 40,000, preferably from 1,000 to 20,000, and more preferably from 20,000 to 20,000.
00-8000. If the molecular weight is less than 500, the degree of polymerization as a polymer unit is too low and the above-mentioned entanglement effect cannot be obtained, and if it exceeds 40,000, the reactivity of the macromonomer is too low and sufficient grafting does not occur. Undesirable.

The number average molecular weight of the above macromonomer is a polystyrene equivalent molecular weight measured by gel permeation chromatography, and the measurement is carried out using, for example, apparatus: high performance liquid chromatography (e.g. Hitachi Model 655), column: polystyrene gel (e.g. Tosoh). ■Made in GMIIXL and G
3000HXL), elution solvent: chloroform, flow rate: 1. It can be carried out using Omj/win, column temperature = 40°C, detector: RI detector.

Further, the proportion of the macromonomer required to function effectively in the present invention is 0.5 to 100 parts by weight, preferably 5 to 100 parts by weight, per 100 parts by weight of the polymerizable monomer.
It is 70 parts by weight. If the proportion of the macromonomer is less than 0.5 parts by weight, sufficient entanglement will not occur, and if it exceeds 100 parts by weight, it will not dissolve in the polymerizable monomer, or even if it dissolves, the viscosity of the polymerizable monomer solution will decrease. This makes it difficult to control the particle size during suspension polymerization, causing problems such as unstable polymerization, and even if the reaction progresses successfully, the resulting polymer requires too many techniques, making it difficult for entanglement to occur. This is undesirable because the probability of this occurring increases and the fixing performance decreases.

As the polymerizable monomer that can be used in the present invention, all polymerizable monomers can be used, for example,
Styrenes such as styrene, chlorostyrene, and α-methylstyrene, vinyl esters such as vinyl acetate, vinyl propionate, and vinyl benzoate, methyl acrylate, ethyl acrylate, n-butyl acrylate, and acrylic acid 1s
o-butyl, dodecyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate,
Methacrylic acid is.

- One or more types selected from (meth)acrylic acid esters such as butyl, dimethylaminoethyl methacrylate, and monobutylaminoethyl methacrylate, and (meth)acrylic acid derivatives such as acrylonitrile and methacrylonitrile. are used in combination.

As the colorant used in the present invention, any suitable pigment or dye can be used. For example, in the case of a black toner, a thermal blank method, an acetylene black method,
In the case of color toners, various carbon blacks and grafted carbon blanks produced by channel black method, furnace black method, lamp black method, etc., contain copper phthalocyanine, monoazo pigments (C, 1, P
igment Red 5. C,1,Pigment
Orange36+ C, 1, Pigment Re
d22), disazo pigment (C, iPigment
Yellow 83L, anthraquinone pigment (C,
1, Pigment Blue 60), disazo dye (Solvent Red 19), rhodamine dye (Solvent Red 49), etc. alone or in combination.
They may be used in a mixture of at least 1 species, and may be contained in an amount of 1 to 30 parts by weight, preferably 5 to 20 parts by weight, per 100 parts by weight of the polymerizable monomer.

As the charge control agent used in the present invention, for example, a negatively chargeable agent such as an azo complex dye, or a positively chargeable agent such as nigrosine may be used, or they may be mixed as necessary to form a polymerizable monomer. 0.01 per 100 parts by weight
It may be contained in an amount of up to 10 parts by weight, preferably 0.1 to 5 parts by weight.

Furthermore, the mold release agent such as low molecular weight polyolefin that can be used in the present invention may be contained in an amount of 0 to 20 parts by weight based on 100 parts by weight of the polymerizable monomer. In this case, it is preferable that a mold release agent such as a low molecular weight polyolefin is also dispersed in the polymerizable monomer together with the coloring agent used in the present invention.

Dispersion stabilizers used during suspension polymerization in the present invention include water-soluble polymer dispersants such as gelatin, starch, hydroxyethyl cellulose, carboxymethyl cellulose, polyvinyl pyrrolidone, polyvinyl alkyl ether, and polyvinyl alcohol, barium sulfate, and calcium sulfate. , barium carbonate, calcium carbonate, magnesium carbonate, calcium phosphate, etc., or a mixture of two or more of them. The amount of these dispersion stabilizers used is 0.5 parts by weight per 100 parts by weight of the polymerizable monomer.
The amount is preferably 20 parts by weight, more preferably 2 to 10 parts by weight.

In addition, when using a poorly water-soluble inorganic dispersant as a dispersion stabilizer during suspension polymerization, an anionic surfactant such as sodium dodecylbenzenesulfonate is used as a dispersion stabilizing aid at a ratio of 0.01 to the dispersion stabilizer. It may be present in a range of ˜IO weight %.

In the present invention, commonly used oil-soluble peroxide-based or azo-based initiators can be used as the polymerization initiator, such as benzoyl peroxide, lauroyl peroxide, 2,
Examples include 2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), orthochlor iM hendiyl oxide, orthomethoxybenzoyl peroxide, and the like. These may be used alone or in combination.

The amount of the polymerization initiator used is preferably 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the polymerizable monomer.

In the present invention, the preferred particle size range for the toner is a number average particle size of 3 to 15, more preferably 5 to 10.
-, and the value y of the particle size variation coefficient defined by the following formula satisfies the range of 15 to 45%.

y = (s/x) S and X in the formula need to indicate the values obtained when the particle size is measured using a Coulter counter using 10,000 or more particles, preferably 30,000 or more particles.

The value of this particle size variation coefficient y is a measure indicating the spread of the particle size distribution of the toner on a number basis, and the smaller this value is, the narrower the distribution is. The number-based scale was adopted here because
This is because the distribution of the fine powder portion is emphasized more than the volume-based scale, and the distribution of the fine powder portion is important for the performance of toners, especially toners manufactured by suspension polymerization.

According to the knowledge obtained by the present inventors, the toner obtained by the suspension polymerization method has a spherical shape or a ping-pong shape with no acute angles, and has various advantages such as good fluidity. However, compared to toner obtained by normal pulverization, the adhesion to the carrier and photoreceptor (van der waals) is lower.
toner particles with larger particle diameters tend to be consumed first.

For this reason, during continuous copying of a large number of sheets, the balance of the particle size distribution of the toner is lost, and furthermore, even if the toner is developed on the photoconductor, it is difficult for toner with a relatively small particle size to separate from the photoconductor. A phenomenon occurs. Therefore, during continuous copying of a large number of sheets, various undesirable situations occur, such as a decrease in image quality, a change in the amount of charge, a decrease in transfer efficiency, and the occurrence of cleaning failures.

As described above, the particle size distribution of toner is very important, and especially in toner produced by suspension polymerization, it is important to minimize the number of fine toner particles. However, it is almost impossible to obtain particles with an extremely narrow particle size distribution by suspension polymerization using mechanical dispersion, and if the particle size distribution is made unnecessarily narrow in this way, it may be difficult to obtain a particle with an extremely narrow particle size distribution. , there are also negative aspects such as loss of gradation.

Therefore, in suspension polymerization toners, there is an optimal particle size distribution range.

According to the findings of the present inventors, in a toner obtained by a suspension polymerization method, a particle size distribution in which the value of the particle size variation coefficient y expressed by the above-mentioned - ship stock satisfies the range of 15 to 45%. If the particle size variation coefficient y is out of the range, the above-mentioned adverse phenomenon will occur in any case.

By the way, JP-A-1-108209 describes obtaining a graft polymer by a suspension polymerization method using a macro-sulfur polymer similarly to the present invention. Particles having a particle size and particle size distribution useful as a toner cannot be obtained using conventional methods. Generally, in the suspension polymerization method, when a toner is synthesized according to a usual recipe, the particle size distribution is very wide, and the particle size variation coefficient y on a number basis shows a value of 50% or more, often 60% or more.

Furthermore, in the method described in JP-A-1-108209, the viscosity of the polymerizable monomer solution increases significantly due to the addition of a monomer, so essential toner components such as colorants and charge control agents are added. Particle size control becomes difficult due to various factors such as difficulty in uniformly dispersing the polymerizable monomer solution, difficulty in atomizing the polymerizable monomer solution, and the tendency for polymerization to become unstable and coalesced particles to form. Both the diameter and particle size distribution tend to be inappropriate as a toner.

However, in the present invention, a colorant, a charge control agent,
Step (1) of uniformly dispersing the macromonomer etc. in the polymerizable monomer using a wet media type pulverizer; A homogeneous toner with stable polymerization and uniform particle size and particle size distribution can be obtained by the step (II) of shearing and dividing the toner to the particle size using a continuous dispersion machine that takes advantage of the following.

Specifically, in step (1), the colorant, charge control agent, etc. are finely crushed or pulverized and homogeneously dispersed in the polymerizable monomer, including the macromonomer, making it difficult to atomize. The destabilization of polymerization is significantly improved and a homogeneous toner can be obtained. In addition, by using a specific dispersion machine such as step (n), particles with an excellent particle size and particle size distribution as a toner can be obtained. is obtained.

In the present invention, a wet media type pulverizer is used to uniformly disperse colorants, charge control agents, macromonomers, etc. into polymerizable monomers, but this pulverizer may be either a continuous type or a batch type. An appropriate one is often selected depending on the processing amount and processing time. For example, a ball mill, an attritor (manufactured by Mitsui Miike Manufacturing Co., Ltd.), etc. can be mentioned.

Further, in the present invention, a continuous dispersion machine using cavitation, swirling flow, or turbulence is used as a means for shearing and dividing the polymerizable monomer mixture into a particle size suitable for toner in an aqueous medium.

Cavitation is a method of applying strong shearing force using the ultrasonic waves generated when a rotor or turbine blade rotates vigorously in a liquid, creating air bubbles behind the blade due to a drop in pressure. Even if ultrasonic waves are used, those using an ultrasonic oscillator are not preferable because the particle size distribution becomes wide. Furthermore, even among those that utilize cavitation, batch type ones are not preferred because the number of times of shearing becomes uneven during repeated shearing, resulting in a wide particle size distribution. An example of a continuous dispersion machine that uses cavitation is a continuous dispersion machine equipped with a stator and a rotor (generator or rotor-stator).
■Mitsui Miike Manufacturing Co., Ltd.), T, Ni, High Line Mill Milder (manufactured by Ebara Corporation), T, Ni, Homo Mitsukline Flow, T, Pipeline Homo Mixer (Tokushu Kika Kogyo ■), etc. However, any other similar method may be used.

On the other hand, examples of dispersion machines that utilize swirling flow or turbulent flow include methods in which the dispersion liquid is ejected at high speed from a nozzle or slit to create a swirling flow due to the force of the liquid; Examples include systems in which turbulent flow is caused by fixed vanes or the shape of the tank interior. Specific examples include Hydrosher (manufactured by Gorlin Corporation),
Static mixer PSM (manufactured by Petzhold)
, T, the rotating whirlpool method such as Fiscalin (manufactured by Tokushu Kika Kogyo ■), Sulzer mixer (Sulzer Brothers ■)
Examples include line mixer type turbulent flow systems such as the High Mixer (manufactured by Toshi Corporation), Noritake Static Mixer (manufactured by Noritake Corporation), and the Noritake Static Mixer (manufactured by Noritake Corporation). All of these are continuous processing methods.

〔Example〕

The present invention will be described in detail below, but the present invention is not limited thereto.

Note that parts in the examples are parts by weight.

Example 1 85 parts of styrene, 15 parts of n-butyl acrylate, 7 parts of carbon black (Mitsubishi Kasei side type, 144), charge control agent (manufactured by Hodogaya Chemical ■, Eisen Spiron Black TR)
) j) 1 part, low molecular weight polyethylene (manufactured by Mitsui Petrochemical Industries ■, Mitsui Hiwax 210P) 2L styrene macromonomer (manufactured by Toagosei Chemical Industry ■, number average molecular weight 3100) Polymerizable by dispersing 30 parts in a ball mill for 8 hours Add 2 parts of 2.2''-azobisisobutyronitrile to the monomer solution, add 10 parts of tricalcium phosphate (manufactured by Katayama Chemical), and sodium dodecylbenzenesulfonate (manufactured by Tokyo Kasei Kogyo). The mixture was added to a mixture of 0.1 part and 400 parts of water, and mixed and stirred.

Next, this mixed liquid was fed to Milder, a continuous dispersion machine using cavitation (manufactured by Ebara Corporation) at a rate of 251 /
sine, passed twice under the conditions of rotation speed 800 rpm,
Suspended and dispersed. This suspension was placed in a separable flask equipped with a dehydration tube, a condenser, and a stirring device for 11 hours.
The polymerization reaction was carried out at 75° C. for 8 hours under a nitrogen atmosphere at a stirring speed of 0.00 rpm.

After the polymerization reaction, filter, wash with hydrochloric acid, wash with water, and heat at 40°C.
The mixture was dried overnight under reduced pressure to obtain a toner.

When the particle size and particle size distribution of the obtained toner were measured using a Coulter counter (TA-n type, aperture diameter 1004), the number average particle size X was 9.8μ, and the standard deviation S of the number distribution of particle size was It was 2.7-. Further, the particle size variation coefficient y determined from these was 27.6%.

Example 2 87 parts of styrene, 13 parts of 2-ethylhexyl acrylate
L carbon black (Columbian Carbon Japan type, RAVEN2100) 7 parts, charge control agent (Orient Chemical Co., Ltd., S-34) 2 parts, low molecular weight polyethylene (Mitsui Petrochemical Co., Ltd., Mitsui Hiwax 210P)
Add 2 parts of 2,2゛-azobisisobutyronitrile to a polymerizable monomer solution in which 30 parts of methyl methacrylate macromonomer (manufactured by Toagosei Kagaku Kogyo Co., Ltd., average molecular weight: 2600) are dispersed in a ball mill for 8 hours. 10 parts of tricalcium phosphate (manufactured by Katayama Kagaku ■) and 0.0 parts of sodium dodecylbenzenesulfonate (manufactured by Tokyo Kasei Kogyo ■).
The mixture was added to a mixture of 1 part and 400 parts of water, and mixed and stirred.

Next, this mixed liquid was dispersed using a hydrosher (manufactured by Gorlin Corporation) using a swirling vortex method. That is, the pressure of the above mixed liquid is 6 kg/cm! (gauge pressure), the mixture was passed through a hydrosher twice to be suspended and dispersed. Thereafter, a toner was synthesized according to Example 1.

When the particle size and particle size distribution of the obtained toner were measured in the same manner, the number average particle size was 11.1 All, and the standard deviation was 2.
It was 4μ. Also, the particle size variation coefficient calculated from these is 2
It was 1.6%.

Example 3 In Example 1, instead of the styrene macromonomer, a styrene-acrylonitrile copolymer macromonomer (manufactured by Toagosei Kagaku Kogyo ■, number average molecular weight 6000) was used.
0 parts were added and dispersed using a turbulent flow type Sulzer mixer (manufactured by Sulzer Brothers ■) instead of a milder. That is, the polymerizable monomer mixture was dispersed in water under the conditions of a nominal diameter of 10.5n+a+φ, a number of elements of 7, and an average tube flow rate of 2 ml/sec. A toner was synthesized in the same manner as in Example 1 except for this.

The number average particle size of the obtained toner was 11.3-, the standard deviation was 3.4 μm, and the particle size variation coefficient was 30.1%.

Example 4 A toner was synthesized in exactly the same manner as in Example 2, except that instead of the methyl methacrylate macromonomer, a silicone macromonomer (manufactured by Toagosei Chemical Co., Ltd., number average molecular weight 500) was added. .

The number average particle size of the obtained toner was 11.3 am,
The standard deviation was 2.9-1 and the particle size variation coefficient was 25.7%.

Comparative Example 1 In Example 1, except that the macromonomer was excluded,
A toner was synthesized in exactly the same manner as in Example 1.

The number average particle diameter of the obtained toner was 11.7μ, and the standard deviation was 2.6 tries. Further, the particle size variation coefficient determined from these was 22.2%.

Comparative Example 2 In Example 2, a crosslinking agent (
A toner was synthesized in exactly the same manner as in Example 2, except that 1 part of divinylbenzene (manufactured by Wako Pure Chemical Industries, Ltd.) was added.

The number average particle size of the obtained toner was 11.2J! m, standard deviation 2.3-1 particle size variation coefficient was 20.5%.

Comparative Example 3 In Example 1, instead of the milder, a batch type TK homo mixer (manufactured by Tokushu Kika Kogyo ■) was used for dispersion. That is, the rotation speed was 6000 r in a separable flask.
The polymerizable monomer mixture was dispersed in water at pm for 3 minutes. A toner was synthesized in the same manner as in Example 1 except for this.

The number average particle diameter of the obtained toner was 10.7-1, and the standard deviation was 6.8-1, and the particle size variation coefficient was 63.6%.

Comparative Example 4 A toner was synthesized in exactly the same manner as in Example 2, except that the mixing and dispersing steps using a ball mill were omitted. During polymerization, the dispersibility was unstable and a large amount of aggregates were produced. The aggregates were removed using a mesh sieve to obtain a toner.

The number average particle diameter of the obtained toner was 16.4, and the standard deviation was 9.1. Further, the particle size variation coefficient determined from these was 55.5%.

Regarding the toners obtained in the above Examples and Comparative Examples, hydrophobic silica "Aerosil R-97" was added to 100 parts of the toner.
After surface treatment was performed by adding 0.3 part of 2J (manufactured by Nippon Aerosil Co., Ltd.), the toner was mixed with resin-coated iron powder so that the toner concentration was 2% by weight to prepare a developer.

Images were produced using a commercially available electrophotographic copying machine using these developers (fixing roller rotation speed was 150 mm/sec, heat roller temperature in the fixing device was variable, and oil application device was removed). .

The fixing temperature was controlled at 120 to 240° C., and the image fixing properties and offset properties were evaluated. Table 1 shows the results.

What is the minimum fixing temperature here? Place a 500 g load on a sand eraser with a 15 x 7.5 mm bottom, rub it back and forth 5 times over the fixed image through the fixing device, and then measure it optically with a Macbeth reflection densitometer before and after rubbing. It refers to the temperature of the fixing roller when the reflection density is measured and the fixing rate exceeds 70% as defined below.

From the results shown in the table, toners according to the present invention (Examples 1 to 4)
It is clear that all of them have excellent particle size distribution and anti-offset properties, and can achieve sufficient fixing properties at low temperatures.

In contrast, a toner that does not contain a macromonomer (Comparative Example 1) has low offset resistance (and a toner crosslinked with a crosslinking agent (Comparative Example 2) has a lower minimum fixing temperature than the toner of the present invention. It is clear that the fixing properties are low.

Furthermore, the toners manufactured in Comparative Examples 3 and 4, which did not include the manufacturing process of the present invention, had particle sizes and/or particle size distributions that were unsuitable as toners.

Incidentally, when a continuous copying test of 50,000 sheets was conducted using these toners, it was found that the toners according to the present invention (Examples 1 to 3)
In 4), in any case, the initial value is 5000.
A good copy image with high image density, clear and fog-free was obtained until the number of sheets reached zero, and there was no occurrence of toner filming on the photoreceptor or toner adhesion to the fixing roller. On the other hand, with the toner of Comparative Example 1, offset occurs from the beginning, and with the toner of Comparative Example 2, the image density is high, a clear copy image without fogging is obtained, and toner filming on the photoreceptor is prevented. Although there was no toner adhesion to the fixing roller, the fixing properties were so poor that it could be rubbed off with a finger. Further, in the toner of Comparative Example 3, a decrease in sharpness and a decrease in image density occurred after the number of copies exceeded 100, and in the toner of Comparative Example 4, fogging occurred from the beginning.

Claims (1)

[Scope of Claims] 1. The number average particle size obtained by suspension polymerizing a polymerizable monomer containing a colorant and a charge control agent in the presence of a macromonomer is 3 to 15 μm, and Particle size variation coefficient y defined by the following formula y = (s/x) x 100 (%) [s is the standard deviation of the particle size number distribution (μm), x is the number average particle diameter (μm)] is 15 to A toner for developing an electrostatic image, characterized in that it satisfies 45%. 2. The number average molecular weight of the macromonomer is 500 to 4000
2. The toner for developing an electrostatic image according to claim 1, wherein the toner is 0. 3. The toner for developing electrostatic images according to claim 1 or 2, wherein the proportion of the macromonomer is 0.5 to 100 parts by weight based on 100 parts by weight of the polymerizable monomer. 4. In a method for producing a toner for developing electrostatic images by suspension polymerization, a step of dispersing a colorant, a charge control agent, and a macromonomer in a polymerizable monomer using a wet media type pulverizer, and a step of dispersing a colorant, a charge control agent, and a macromonomer in an aqueous medium. An electrostatic charge characterized by comprising a step of shearing and dividing the droplets of the polymerizable monomer mixture to a particle size suitable for the toner using a continuous disperser using cavitation, swirl flow, or turbulence. A method for producing toner for image development.