JPS62299863A - Production of toner for developing electrostatic charge image - Google Patents

Abstract

PURPOSE:To efficiently obtain a toner which permits easy control of an average grain size and has an extremely narrow grain size distribution by incorporating a dispersion stage consisting in projecting ultrasonic waves to a dispersion stabilizer in a liquid dispersion medium to the titled method. CONSTITUTION:Toner particles are formed by projecting the ultrasonic waves to the liquid dispersion medium contg. the fine powder dispersion stabilizer to disperse the dispersion stabilizer into said medium, dispersing and suspending a monomer compsn. contg. at least a polymerizable monomer and coloring agent in the liquid dispersion medium dispersed with the dispersion stabilizer by the dispersion stage, granulating the compsn. and subjecting the granulated monomer compsn. to a suspension polymn. The fine powder dispersion stabilizer which as the sharp grain size distribution and improved dispersion stabilizing capacity is thereby made to exist on the particle surface of the monomer compsn. by which the monomer compsn. particles having the desired grain size is selectively stabilized and the sharp grain size distribution of the monomer compsn. particles is formed.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention Ueno The present invention relates to a toner for developing electrostatic images in image forming methods such as electrophotography, electrostatic photography, and electrostatic printing. More specifically, the present invention relates to a method for producing a toner for developing electrostatic images using an improved suspension polymerization method, which includes a granulation step for efficiently forming particles with a sharp particle size distribution.

11. Conventionally, methods for developing an electrostatic image formed on a recording medium in electrophotography, electrostatic recording, or electrostatic printing can be broadly classified into methods using various pigments or pigments in an insulating liquid. A liquid development method using a developer made by dispersing a dye, a cascade method using fine particles called a toner made by dispersing a coloring agent such as carbon black in a natural or synthetic polymer or wax, and a bristle brush method. There are so-called dry developing methods such as the magnetic brush method, the impression method, and the powder cloud method.

The liquid developing method has problems such as the processing of the developer used therein is troublesome and a unique unpleasant odor is generated during and after the development and fixing process, so the dry developing method using the toner is mainly used. It is put into practical use.

The toner for developing electrostatic images used in the dry development method is usually
For example, a binder made of a vinyl polymer such as polystyrene or polyacrylic acid ester, an epoxy polymer, a petroleum polymer, an ester condensate, etc., and a coloring agent such as carbon black are mixed, melted and kneaded, It is manufactured by cooling, pulverizing, and further classifying the toner particles to have a particle size of 1 to 50 gttr. The toner formed in this manner is required to satisfy certain characteristics such as storage stability, durability, moisture resistance, electrostatic properties, fluidity, fixability, and imageability.

It is said that the majority of dry toners currently on the market are manufactured by this pulverization method, as forming toner by the so-called pulverization method described in 2 has many advantages. .

However, this manufacturing method has many problems. In other words, in the pulverization method, the wind-powered collision type pulverizer that is used for the main part of the pulverization process uses a large amount of compressed air, requiring a large amount of equipment cost, and also consumes a lot of electricity during operation. - These costs are added to toner] -
It accounts for the majority of expenses. In particular, in recent years, there has been a demand for toner with small particle size due to the demand for higher quality copied images, but with the current pulverization method, which consumes a large amount of energy, it is difficult to efficiently generate toner with small particle size. is difficult,
This will result in a considerable increase in costs. In addition, when toner with a small particle size is generated by pulverization V, the particle size distribution of the pulverized product tends to be broad and a large amount of unnecessary ultrafine powder is generated, and it is extremely difficult to remove the generated ultrafine powder by classification. It is.

Furthermore, in order to be effectively pulverized in this pulverization method, the toner material must have appropriate brittleness, and the selection of raw materials is limited to those having such brittleness. Additionally, when softer materials are used to improve toner fixation, the heat and pressure generated during pulverization tend to cause fusion in the equipment used in various processes. In such a case, it becomes impossible to operate the toner manufacturing apparatus continuously for a long time.

In order to overcome these problems, a toner production method using a suspension polymerization method that does not involve dry pulverization has been proposed. This method is an excellent method that eliminates the above-mentioned disadvantages by omitting the melt-kneading process and the grinding process.However, in dry toner production using the conventional suspension polymerization method, the following points are New problems are arising.

That is, firstly, in toner production using a normal suspension polymerization method, a liquid @ containing a monopolymerizable monomer and a colorant is used.
In the granulation step, the polymer composition is granulated in a liquid dispersion medium,
There is a problem in that it is very difficult to efficiently control the monomer composition particles to a desired particle size. Secondly, in the current suspension polymerization method, the particle size distribution of the produced polymer particles is wide, and polymer particles with large particle sizes are produced, so the weight proportion of particles in the appropriate particle size range is small. , productivity is not good. In the above-mentioned pulverization method, the particles removed in the classification operation to obtain a suitable particle size range can be re-mixed with the raw materials and then reused through the cross-mixing process.
In this suspension polymerization method, it is currently difficult to reuse the resulting polymer particles of poor particle size.

In the suspension polymerization method, in order to solve the problem of particle size distribution as described above, it is necessary to granulate monomer composition particles with a particle size that can finally produce a toner with a desired particle size distribution. It is necessary to produce stable yields in the process, but
In this respect, conventional suspension polymerization methods still have many problems to be solved.

One of the most important of these issues is the issue of dispersion stabilizers to obtain proper particle size distribution. In other words, in the suspension polymerization method, the main steps are carried out in a liquid medium (
(Usually water is used as a medium), but in the granulation process,
Dispersion stabilizers are used to form and stabilize monomer composition particles. Such dispersion stabilizers are usually BaSO4, Ca5O, CaC0, poorly water-soluble inorganic fine powder such as silica, polyvinyl alcohol,
Water-soluble polymers such as gelatin, water-soluble surfactants, etc. are used singly or in combination.

These dispersion stabilizers have strong hydrophilic properties due to their role, and if they remain in the produced toner, the developing ability and transfer efficiency will decrease mainly due to a decrease in the chargeability of the toner. In particular, under conditions of high humidity, image quality such as a decrease in copy density, a decrease in resolution, and blurring and flickering occur. Therefore, from this point of view, it is required to reduce the amount of dispersion stabilizer used as much as possible, but at the same time, use a small amount of dispersion stabilizer to reduce the particle size of the monomer composition and improve the particle size distribution. We must solve the problem of sharpening the image.

In order to solve this problem, we have improved the material of the dispersion stabilizer itself,
Efforts have been made to reduce the amount of dispersion stabilizer used in the conventional granulation process, but in the conventional granulation process, reducing the amount of dispersion stabilizer by one level results in the monomer composition particles becoming coarser and having a wider particle size distribution. Since secondary aggregation of monomer composition particles frequently occurs, it becomes difficult to obtain a polymer with an appropriate particle size. Especially when trying to obtain toner with small particle size, these two
Subaggregation becomes an extremely serious problem.

11 An object of the present invention is to provide a toner production method that can easily control the average particle size and efficiently produce toner with an extremely narrow particle size distribution in the production of toner for electrostatic image development using a suspension polymerization method. Our goal is to provide the following.

Another object of the present invention is to provide a method for efficiently producing dry toner with small particle size.

Still another object of the present invention is to provide a method for producing a toner having a homogeneous and sharp particle size distribution while reducing the amount of dispersion stabilizer used in toner production using a suspension polymerization method. .

Still another object of the present invention is to provide a method for producing a toner having good powder characteristics and good development, transfer, fixing, and cleaning properties.

Still another object of the present invention is to provide a method for producing toner at low cost and with good productivity.

As a result of intensive research, the present inventors have found that in the granulation process when obtaining toner by suspension polymerization, under actual granulation conditions (particularly in the presence of a dispersion medium consisting of water, etc.) It has been found that the particle size distribution of the dispersion stabilizer itself (how sharp the particle size distribution is) is an extremely important issue.

The present inventors conducted further research based on the above findings and found that instead of adding the fine powder stabilizer directly to the mixed system (dispersion) to be granulated, (before adding the monomer composition) ) Introducing a dispersion process in which the dispersion stabilizer in the liquid dispersion medium is irradiated with ultrasonic waves to achieve a sharp particle size distribution of the dispersion stabilizer itself in the liquid dispersion medium is extremely effective in achieving the above-mentioned objective. I found that it was true.

The toner manufacturing method of the present invention is based on such knowledge, and more specifically, the toner manufacturing method of the present invention is based on the above-mentioned knowledge. and a granulation step of dispersing, suspending and granulating a monomer composition containing at least a polymerizable monomer and a colorant in a liquid dispersion medium in which a dispersion stabilizer is dispersed in the above dispersion step. and a polymerization step of subjecting the granulated monomer composition to suspension polymerization to form toner particles.

Although the reason why the present invention achieves the effects described in -1- is not necessarily clear, it is presumed as follows.

In the dispersion process of the present invention, the instantaneous and impactful high pressure generated by cavitation, which is a characteristic of ultrasonic waves, causes the fine powder dispersion stabilizer to form strong aggregates (secondary particles) and not work effectively. The aggregates are destroyed by ultrasonic waves, becoming more like ultrafine particles, and are well dispersed in the liquid dispersion medium, thereby realizing a sharp particle size distribution of the fine powder dispersion stabilizer itself in the liquid dispersion medium. Ru.

As a result, in the granulation process, the dispersion stabilizing effect (by the coarse powder dispersion stabilizer) on monomer composition particles with a desired particle size is suppressed to a low level, while the monomer composition with a desired particle size Since the dispersion stabilizing effect on the monomer composition particles is significantly enhanced, the number of monomer composition particles having the above-mentioned predetermined particle size increases significantly, and an extremely sharp particle size distribution of the monomer composition particles can be obtained. In addition, since the dispersion stabilizing ability of the dispersion stabilizer as a whole is improved, it is estimated that the amount of dispersion stabilizer used can be reduced compared to the conventional method.

The present invention will be explained in more detail below. In the following description, "parts" and "%" expressing quantitative ratios are based on weight unless otherwise specified.

EJLa In the production method of the present invention, a liquid dispersion medium containing a fine powder dispersion stabilizer such as fine silica powder is irradiated with ultrasonic waves to disperse the dispersion stabilizer (dispersion), and then styrene is dispersed. A liquid is prepared by dispersing a monomer composition containing a polymerizable monomer such as , a coloring agent such as carbon black, and a dispersion stabilizer in advance through the above-mentioned dispersion process. The medium composition is poured into a dispersion medium, and is dispersed, suspended, and granulated using a means such as a high shear force stirring device or a piston-type high-pressure homogenizer (Pelletization 7)
2 degrees). As a result, in the granulation process, the presence of a fine powder dispersion stabilizer with a sharp particle size distribution and improved dispersion stabilizing ability on the particle surface of the monomer composition allows monomers with a desired particle size to be formed. the polymeric composition particles are selectively stabilized;
A sharp particle size distribution of the monomer composition particles is achieved.

As the ultrasonic irradiation device used in the step of dispersing the dispersion stabilizer, one having a vibrator and an oscillator for generating intensive ultrasonic energy in the liquid is preferably used. Such a device is generally used as a homogenizer.

Examples of such dispersion means used in the present invention include:
■ Devices manufactured by Kiseiki Seisakusho, such as an IFL sonic homogenizer, a closed type ultrasonic homogenizer, a continuous type ultrasonic homogenizer, a circulating two-wave ultrasonic homogenizer, an ultrasonic mill, and a multi-stage ultrasonic dispersion device, can be mentioned.

In the present invention, the ultrasonic dispersion apparatus is of a type in which a vibrating body is present outside the container (not shown), and as shown in FIG. As shown in FIG. 2, the ultrasonic irradiation section 4 is made of a thick-walled structure so that the ultrasonic irradiation section 4 becomes an acoustic steel wall. Any structure can be used in which the sound wave energy generated from the radiation surface of the vibrating body 3 is collected within the wall without leaking outside by providing the irradiation wall 5 that surrounds the vibrating body 3. However, a system in which the irradiation section 4 is surrounded by a structure as shown in FIG. 2 is preferably used. In the method shown in Fig. 2, compared to the method in which a vibrating body is introduced (Fig. 1), the sound wave energy is collected within the wall without leaking outside, and moreover, the irradiation section 4 is a liquid (incompressible fluid). ), the liquid dispersion medium 2 is intensively irradiated with extremely strong ultrasonic energy, making it possible to improve the uniformity of separation and the efficiency of breaking up aggregates.

The ultrasonic dispersion device used in the present invention has an oscillation frequency of 10
KHz ~ 50K) lz, output is 50W ~ 2000W
, and more preferably in the range of 200 to 2000W.

In the granulation process of the present invention, a plurality of devices shown in Fig. 1, 2, or 3 (Fig. 2) are arranged in series. When using devices such as
In the ultrasonic irradiation section 4, the liquid dispersion medium 2 is usually
The dispersion stabilizer is preferably dispersed by ultrasonic irradiation for ~60 minutes or by one or more passes.

If this ultrasonic irradiation time is less than 1 minute, efficient dispersion of the dispersion stabilizer will be difficult due to the lack of irradiated ultrasonic energy; on the other hand, if the irradiation time exceeds 60 minutes (there is no problem in itself) ), it becomes difficult to recognize a significant improvement in the dispersion effect beyond a certain level.

In particular, when using the closed type apparatus shown in FIG. 2 or 3, it is preferable to disperse the liquid dispersion medium 2 by passing it 1 to 1000 times (with a relatively short irradiation time per time).

The liquid temperature during the dispersion step may be room temperature or a higher temperature, but a high temperature is generally preferred. It is preferable to set this liquid temperature to the temperature during polymerization from the viewpoint of improving the efficiency of the process.

This dispersion step may be performed in a (relatively large capacity) container used for the next granulation step, but from the point of view of efficient and uniform dispersion, it is recommended to perform it in a container separate from the granulation step (relatively Preferably, it is carried out in a container (of small volume).

In the production method of the present invention, I.ner particles are produced through a dispersion process, a granulation process, and a suspension polymerization process.
As shown in the process diagram in FIG. 4, toner particles may be manufactured by successively passing through a dispersion step, a granulation step, and a polymerization step, or as shown in FIG. 5, after the dispersion step is completed, After repeating the dispersion process again by circulating the dispersion process continuously or intermittently, the granulation process 1 and the polymerization process are carried out.・
ner particles may also be produced.

Furthermore, Fig. 6 (method using the single dispersion device shown in Fig. 2 for the first dispersion step) or Fig. 7 (method using the multi-stage dispersion device shown in Fig. 3 for the first dispersion step) As shown in the process diagram, the dispersion process is carried out n times in series (usually n = 2 to 1,
000)<It is also good to repeat.

In addition, in the dispersion process using an ultrasonic dispersion device, a high-shear stirring device such as a TK homomixer, a piston-type high-pressure homogenization device, etc. connected to the ultrasonic dispersion device (for example, connected before the ultrasonic dispersion device) is used. It is also effective to use a generally known emulsifying and dispersing device.

The liquid dispersion medium in which the dispersion stabilizer has been well dispersed through the above-mentioned dispersion step is subjected to the next granulation step ( or preliminary granulation step).

It is also effective to provide a preliminary granulation step of the monomer composition after this dispersion step and before the granulation step.

Here, the pre-granulation step refers to a monomer composition containing a polymerizable monomer such as styrene, a colorant such as carbon black (polymerization initiator, etc. if necessary), and a dispersion stabilizer present. This refers to the process of preliminary granulation in a liquid dispersion medium using a dispersion means such as a high shear force stirring mixer. Because the particles of the monomer composition pre-granulated in this way have a dispersion stabilizer with improved dispersion stabilizing ability on the particle surface, even after the stirring by the stirring means is stopped, It remains in a particle state for a while.

Next, the granulation process will be described.

Granulation of the monomer composition into a liquid dispersion medium can be carried out, for example by TK
The monomer composition can be prepared at this stage using a commonly known device such as a high-shear mixer such as a Homomixer or an Ultra Homomixer, or a piston-type high-pressure homogenizer for 1 to 60 minutes. Alternatively, after the granulation process is completed, the polymerization initiator is added to the liquid medium containing the monomer composition particles adjusted to the polymerization temperature and suspended. It may also be subjected to a polymerization reaction.

Further, in the granulation step, it is preferable to repeat the granulation step by circulating the dispersion liquid continuously or intermittently, from the viewpoint of sharpening the particle size distribution. Furthermore, in the granulation process, the granulation devices are connected in series, and n bits are
(Usually n=1-1000)<May be repeated.

In the present invention, the micronized monomer composition particles are protected with a fine powder dispersion stabilizer that has improved dispersion stabilizing ability. therefore.

- If a sharp particle size distribution cannot be obtained by passing through the granulation process multiple times, even if the granulation process is performed multiple times,
The possibility that monomer composition particles having a desired particle size will be further fragmented is extremely small compared to conventional granulation methods.

The liquid temperature during the granulation step in the present invention is such that the monomer composition has a viscosity of 1 to 1 million cps, preferably 100,000 to 100,000 cps.
When the temperature is adjusted to s, the particle size of the monomer composition particles can be adjusted to 1 to 20 gm, and a developing toner having a volume average particle size of 1 to 20 lLr5 can be produced. As the dispersion medium constituting the liquid dispersion medium, water or an aqueous medium containing water as a main component is usually used, so the liquid temperature of the dispersion consisting of the liquid dispersion medium and the monomer composition is 20 to 80℃.
The temperature is preferably adjusted to 40 to 70°C.

, h In the dispersion, it is preferable that the liquid dispersion medium is present in an amount of 200 to 1000 parts with respect to 100 parts of the monomer composition. The dispersion stabilizer is preferably used in an amount of 1 to 20 parts, more preferably 2 to 15 parts, based on 100 parts of the monomer composition.

In the granulation process of the present invention, by combining with the dispersion process of the dispersion stabilizer itself as described above, approximately 1 to 20
When cow and dairy product composition particles having the same -qi average particle diameter and the volume average particle diameter of Kakusari are produced as medium clear composition particles without passing through -1-dispersion=[(conventional method) ) ~90%~lO
It is possible to perform granulation by using a dispersion stabilizer of approximately 1.5%. Furthermore, in the present invention, due to the dispersion stabilizing ability of the dispersion stabilizer itself, it is also possible to make the time for granulation at about 1" shorter than in the past.

Before the monomer composition particles formed by the granulation step as detailed above are subjected to the next polymerization step, the monomer composition particles may be subjected to a classification treatment, if necessary.

This classification process can be performed, for example, using a wet classifier, but at this time, particles of the desired particle size generated during granulation are
After being separated from particles with a particle size outside the specified size using a classifier, the particles are led to a polymerization process using a gentle stirring device set to conditions that prevent particles from coalescing or collapsing, resulting in a single polymerization reaction. It is offered to

On the other hand, the non-standard coarse particles separated by the classifier are returned to the granulation process, and then subjected to the granulation process to obtain particles of the desired particle size, and then sequentially taken out in the same manner as above, and similarly subjected to the polymerization process. provide

As a result, coarse particles can be atomized as desired without being affected by the miniaturization of monomer composition particles having a desired particle size, making it possible to improve the yield in the granulation process.

When performing such a classification process, it is preferable to use a so-called wet classifier that utilizes the difference in sedimentation speed of particles in a liquid.

Wet classifiers are classified into settling tank type, mechanical classifier type, hydraulic classifier type, hydrocyclone type, centrifugal classifier type, inertial force classifier type, etc. In the present invention, hydraulic classifier type, Hydrocyclone type, centrifugal classification type, and inertial force classifier type are preferably used.
In particular, hydrocyclone type, centrifugal classifier type, and inertial force classifier type are preferably used.

Next, the materials constituting the body composition will be simply explained.

The polymerizable composition used in the present invention is a monomer having a CH2=C group, and the monomer as shown below is
can be given.

Namely, styrene 10-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3.4
-dichlorostyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-n-butylstyrene, p-ter
t-butylstyrene, p-n-hexylstyrene, p-
n-octylstyrene, p-n-7nylstyrene, p-
Styrene and its derivatives such as n-decylstyrene and p-n-dodecylstyrene; ethylenically unsaturated monoolefins such as ethylene, propylene, butylene, and isobutylene; vinyl chloride, vinylidene chloride, vinyl bromide, vinyl fluoride, etc. Vinyl halides; acid-resistant vinyl, vinyl propionate, vinyl esters such as vinyl benzoate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, methacrylate dodecyl acid, 2-ethylhexyl methacrylate,
α-methylene aliphatic monocarboxylic acid esters such as stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylamine ethyl methacrylate; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, acrylic Acrylic acid esters such as propyl acid, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, and phenyl acrylate; maleic acid, maleic acid halfester: vinyl methyl ether, Vinyl ethers such as vinyl ethyl ether and vinyl isobutyl ether; Vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and methyl isopropenyl ketone; N-vinylpyrrole, N-vinylcarbazole, N-
N-vinyl compounds such as vinyl indole and N-vinylpyrrolidone; vinylnaphthalenes; acrylonitrile,
Acrylic acid or methacrylic acid derivatives such as methacrylate tolyl and acrylamide; etc. alone or in combination
Can be used in combination of more than one species.

Among the above-mentioned hexamers, it is preferable to use styrene or a styrene derivative alone or in combination with other hexamers as a polymerizable monomer in order to improve the development characteristics and durability of the toner.

The monomer composition contains N-type waxes such as paraffin wax, and low molecular weight polyolefins such as low molecular weight polyethylene and low molecular weight polypropylene, in order to improve fixing properties and offset resistance in hot pressure roller fixing. It is preferable to add a low softening point compound having . In this case, the amount of the low softening point compound added is 1 to 300 parts per 100 parts of the polymerizable monomer.

Examples of low softening point compounds include paraffin, wax, low molecular weight polyolefin, modified wax having an aromatic group,
Examples include hydrocarbon compounds having an alicyclic group, natural waxes, long-chain carboxylic acids having a long-chain hydrocarbon chain having 12 or more carbon atoms [CH3 (:CH2γ11 or +CH2+ aliphatic carbon chain having 12 or more]), esters thereof, etc. A mixture of different low softening point compounds may be used.

Examples of such low softening point compounds include paraffin wax (manufactured by Nippon Oil), paraffin wax (manufactured by Hiki Seiro), microwax (manufactured by Nippon Oil), microcrystalline wax (manufactured by Hiki Seiro), Hard paraffin wax (manufactured by Nippon Seiro), PE-130 (manufactured by Hoechst)
; Mitsui Hiwax ll0P, Mitsui Hiwax 220
P, Mitsui Hiwax 660P, Mitsui Hiwax 21
0F, Mitsui Hiwax 320P, Mitsui Hiwax 4
10F, Mitsui Hiwax 420P, High 1z-7T
-100X, Highlets T-200X, Highlets T-
300x, Vetrogin 80, Vetrogin 100, Vetrogin 120, Tac Ace A-1oo, Tac Ace F
-100, Tac Ace B-60, modified wax JC-
Examples include beeswax, carnauba wax, montan wax, etc.

In order to produce a crosslinked polymer, the following crosslinking agent may be present in the monomer composition and suspension polymerization may be carried out. especially,
When a polymer, copolymer or cyclized rubber is not added to the monomer composition, it is preferable to add a crosslinking agent.

Examples of the crosslinking agent include divinylbenzene, divinylnaphthalene, polyethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, and 1,3-butylene glycol dimethacrylate.

1.6-hexane gelicol dimethacrylate, neopentyl glycol dimethacrylate, dipropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, 2.2"-bis(4-methacryloxyjetoxyphenyl)propane, 2.2'-bis (4-
General crosslinking agents such as acryloxyjetoxyphenyl)propane, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, tetramethylolmethanetetraacrylate, dibromneopentyl glycol dimethacrylate, and diallyl phthalate may be used as appropriate. can.

If the amount of these crosslinking agents used is too large, the toner will be difficult to melt with heat, resulting in poor heat fixing properties or heat pressure fixing properties. Also, if the amount of crosslinking agent used is too small, properties such as blocking resistance and durability necessary for toner will deteriorate, and during hot roll fixing, some of the toner will not completely adhere to the paper and will adhere to the roller surface. , it becomes difficult to prevent the phenomenon of transfer to the next paper. Therefore, the amount of these crosslinking agents to be used is preferably 0.001 to 15 parts (more preferably 0.31 to 10 parts) per 100 parts of the polymerizable monomer.

As the coloring agent contained in the monomer composition, conventionally known dyes or known pigments such as carbon black and grafted carbon black, which is obtained by coating the surface of carbon black with a resin, are used. It is possible. The colorant is used in an amount of 0.1 to 3 parts per 100 parts of the polymerizable monomer.
0 copies used.

If necessary, a charge control agent and a fluidity modifier may be added (internally added) to the toner thus obtained. Charge control agent and fluidity modifier are mixed with toner particles (external addition)
It may also be used as

Examples of charge control agents include metal complexes of organic compounds having carboxy groups or nitrogen-containing groups, metal-containing dyes, and nigrosine. Examples of fluidity modifiers or cleaning aids for the surface of the latent image carrier (photoreceptor) include colloidal silica and fatty acid metal salts. Also, for the purpose of increasing the amount, calcium carbonate,
A filler such as finely divided silica may be incorporated into the toner in an amount of 0.5 to 20% by weight. Furthermore, in order to prevent mutual agglomeration of toner particles and improve fluidity, fine Teflon powder or stearic acid (flowability agent such as lead powder) may be blended.

To produce a magnetic polymerized toner, magnetic particles may be added to the monomer composition, and in this case, the magnetic particles also serve as (all or part of) a colorant.

The magnetic particles that can be used in the production method of the present invention include substances that are magnetized when placed in a magnetic field, such as powders of ferromagnetic metals such as iron, cobalt, and nickel, or magnetite, hematite, Examples include powders of alloys and compounds such as ferrite. As the magnetic particles, magnetic fine particles having a particle size of 0.05 to 5 g+m, preferably 0.1 to Igm are used, but when producing a small particle size toner, magnetic particles with a particle size of 0.8 ILm or less are used. Preference is given to using particles. This magnetic particle has a monomer composition of 10
It is preferable to use 10 to 150 parts, more preferably 20 to 100 parts, relative to 0 parts.

Further, these magnetic fine particles may be treated with a surface treatment agent such as a silane coupling agent or a titanium coupling agent, or an appropriate reactive resin. In this case, although it depends on the surface area of the magnetic fine particles or the density of hydroxyl groups present on the surface, the amount of surface treatment agent etc. is usually 10 parts or less (preferably 0.1 to 5 parts) per 100 parts of the magnetic fine particles. ) is sufficient for polymerization f'! Dispersibility into intermediates is obtained,
It does not have any adverse effect on toner material I. Further, magnetic particles made lipophilic by the above treatment and untreated hydrophilic magnetic particles may be mixed and used.

Next, the polymerization initiator used in the polymerization of the ig composition consisting of two consecutive materials will be described.

According to the findings of the present inventors, when a water-soluble polymerization initiator is used, the moisture resistance of the polymerized toner that is produced decreases, and the development characteristics and blocking resistance at high temperature and high humidity deteriorate. In order to produce a polymerized toner with excellent environmental properties, it is preferable to use a substantially water-insoluble polymerization initiator.

Here, in the present invention, a substantially water-insoluble polymerization initiator has a solubility of 1 g or less per 100 g of water at room temperature, and preferably has a solubility of 0 g or less per 100 g of water.
．． 5g or less, particularly preferably 0.2 per 100g of water
It has a low solubility of less than g.

If the polymerization initiator has a solubility of 1 g or more per 100 g of water, the decomposition products of the polymerization initiator remaining on the surface of the polymerized toner particles after the end of polymerization will reduce the moisture resistance of the polymerized toner. Undesirable.

The polymerization initiator used in the present invention is preferably soluble in the polymerizable monomer (1) in the amount range normally used (for example, 1 to 10 parts of the polymerization initiator per 100 parts of the polymerizable monomer). ) preferably has solubility characteristics that allow it to dissolve well in the polymerizable monomer.

Examples of such polymerization initiators include 2,2'-7zobis-(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, and l.

Azo-based compounds such as 1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, and other azobisisobutyronitrile (A I B N) Or diazo polymerization initiators; examples include peroxide polymerization initiators such as benzoyl peroxide, methyl ethyl ketone peroxide, isopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorylbenzoyl peroxide, and lauroyl peroxide. .

In the production method of the present invention, it is also preferred to use a mixture of two or more types of polymerization initiators for the purpose of adjusting the molecular weight and molecular weight distribution of the polymer, or for the purpose of adjusting the reaction time.

The amount of the polymerization initiator used is usually 0.1 to 20 parts, preferably 1 to 10 parts, based on 100 parts of the polymerizable monomer. If the amount of the polymerization initiator is less than 0.1 part, it is difficult to disperse or apply a sufficient amount of the polymerization initiator evenly to each monomer composition particle, whereas if the amount of one polymerization initiator exceeds 20 parts. and,
As the molecular weight of the polymerization product decreases, the tendency for the polymerization reaction to occur non-uniformly increases.

In the present invention, the suspension polymerization reaction is usually carried out at a polymerization temperature of 50
The upper temperature limit is set in consideration of the decomposition rate of the polymerization initiator. If the set polymerization temperature is too high, the polymerization initiator will be rapidly decomposed, which is not preferable.

After confirming that the monomer composition particles formed by the granulation process have a predetermined particle size, the liquid temperature (for example, 55 to 70 ° C.) of the dispersion medium such as an aqueous medium containing the particles is adjusted. The polymerization reaction is allowed to proceed.

Furthermore, an additive consisting of a polar polymer, a polar copolymer, a cyclized rubber, etc. having a polar group that is soluble in the polymerizable monomer is added to the monomer composition, and the polymerizable monomer is polymerized. Then, a polymerized toner having preferable characteristics can be obtained.

The polar polymer, polar copolymer or cyclized rubber may be used in an amount of 0.5 to 50 parts, more preferably 1 to 50 parts, based on 100 parts of the polymerizable monomer.
It is recommended to add 40 parts. If the amount of the polar polymer, etc. is less than 0.5 parts, it is difficult to form a sufficient quasi-capsule structure as described below with one polymerizable monomer, and if the amount of the polymer, etc. exceeds 50 parts, the amount of polymerizable monomer If the amount is insufficient, there is a strong tendency for the properties as a polymerized toner to deteriorate.

A polymerizable monomer composition to which a polar polymer, a polar copolymer, or a cyclized rubber is added is added to the aqueous phase of an aqueous medium in which the polar polymer, etc. and an oppositely charged fine powder dispersion stabilizer are dispersed. It is preferred to suspend and polymerize. That is, a cationic or anionic polymer contained in the polymerizable monolithic composition,
A cationic or anionic copolymer or anionic cyclized rubber is a material that combines an oppositely charged 7-ionic or cationic fine powder dispersion stabilizer dispersed in an aqueous medium and an electrostatic charge on the surface of the toner particles. The particle surfaces are covered with a fine powder dispersion stabilizer, thereby preventing the particles from coalescing and stabilizing them. In addition, since the added polar polymer, polar copolymer, or cyclized rubber gathers on the surface layer of the particles that will become the toner, the polar polymer etc. forms a kind of shell-like form, and the resulting particles are It comes to have a pseudo capsule structure. The relatively high molecular weight polar polymer, polar copolymer or cyclized rubber gathered on the surface layer of the particles gives the toner particles excellent properties such as blocking resistance, developability, charge controllability, and abrasion resistance. Grant.

Some of the polar polymers (hereinafter used to include polar copolymers and cyclized rubbers) that can be used in the present invention are illustrated below. Incidentally, a polar polymer having a weight average molecular weight of 5,000 to 500,000 as measured by GPC is preferably used because it dissolves well in the polymerizable monomer and has durability.

(1) Examples of cationic polymers include polymers of nitrogen-containing monomers such as dimethylamine ethyl methacrylate and diethylaminoethyl acrylate, copolymers of styrene and the nitrogen-containing monomers, or styrene and unsaturated carboxylic acid esters. There are also copolymers of these nitrogen-containing monomers.

(2) Examples of anionic polymers include nitrile monomers such as acrylonitrile, halogen-containing monomers such as vinyl chloride, unsaturated carboxylic acids such as acrylic acid, unsaturated dibasic acids,
There are polymers or copolymers of anhydrides of unsaturated dibasic acids, or copolymers of styrene and these monomers. Cyclized rubbers and polyesters can also be used as anionic polymers.

In the present invention, the fine powder dispersion stabilizer is preferably an inorganic fine powder that has the ability to stabilize the dispersion of the monomer composition core in a liquid medium such as an aqueous medium and is sparingly soluble in water. used. The addition h1 of the dispersant into the aqueous medium is 1 to 20 parts (more preferably 2 parts) per 100 parts of the monomer composition.
~15 parts) is good.

As an anionic fine powder dispersion stabilizer, Aerosil #2
00. #300 CB Hon Aerosil Co., Ltd.) Nib Seal E
-22OA ([(made of wood silica), Fine Seal T-3
Colloidal silica such as No. 2 (Tokuyama 1jlt Tatsujyo) can be mentioned.

Examples of the cationic fine powder dispersion stabilizer include aluminum oxide, magnesium liquefaction, and wood-philic positively chargeable silica fine powder such as aminoalkyl-modified colloidal silica treated with a coupling agent. Particularly preferred is a dispersant treated with a coupling agent.

Although a dispersion stabilizer is necessary in the production method of the present invention, it is not necessarily necessary to use a dispersion stabilizer that has counterloading properties in the polar polymer and the liquid medium.

Suitable stabilizers may also be used, such as polyvinyl alcohol, gelatin, methylcellulose, methylhydropropylcellulose, ethylcellulose, carboxymethylcellulose, sodium salts, polyacrylic acid and their salts, starch, gum alginate, zein, casein, phosphorus. In the production of the present invention, one or a mixture of two or more of tricalcium acid, talc, barium sulfate, bentonite, aluminum hydroxide, ferric hydroxide, titanium hydroxide, sodium hydroxide, etc. is added to an aqueous medium. It may be contained and used within a range that does not adversely affect the method.

Further, for uniform dispersion of the inorganic dispersion stabilizer, a surfactant may be used within a range that does not adversely affect the production method of the present invention. This is to promote the intended action of the above-mentioned dispersion stabilizer, and specific examples thereof include sodium dodecylbenzenesulfonate, sodium tetradecylsulfate, sodium pentadecylsulfate, sodium octylsulfate, and allyl-alkyl-polyether. Sodium sulfonate, sodium oleate, sodium laurate, sodium caprate, sodium caprylate,
Sodium caproate, potassium stearate, calcium oleate, 3,3-disulfondi, phenylurea-4,4-diazo-bis-amino-8-naphthol-6
-sodium sulfonate, or-I-carboxybenzene-azo-dimethylaniline, 2,2,5.5-tetramethyl, triphenylmethane-4,4-diazo-bis-
Examples include sodium β-naphthol-disulfonate and others. However, it should be noted that when a hydrophilic organic stabilizer or surfactant is used, the moisture resistance of the polymerized toner tends to decrease.

In order to improve granulation properties when a polar group of a polar polymer or cyclized rubber is included in the monomer composition, it is also preferable to add a Brønsted acid such as hydrochloric acid to the aqueous medium. In particular, adding a Brønsted acid such as hydrochloric acid to an aqueous medium can further enhance the effect of an anionic polymer, anionic copolymer or cyclized rubber and a dispersant, especially a cationic fine powder dispersant. is valid.

After the polymerization reaction is completed, polymerized toner particles can be obtained by post-treatment using a conventional method. For example, a polymerized toner can be obtained by washing the produced polymer particles to remove the dispersion stabilizer, collecting them by an appropriate method such as filtration, decantation, centrifugation, etc., and drying them.

The polymerized toner obtained by the production method of the present invention can be applied to known dry electrostatic image developing methods without particular limitations. This polymerized toner can be used, for example, by a two-component development method such as a cascade method, a magnetic brush method, a microtoning method, a two-component AC bias development method; a conductive-component development method, an insulating-component development method;
One-component development method using magnetic toner such as jumping development method: Powder cloud method and fur brush method; Toner is held on a toner carrier by electrostatic force and transported to a developing section for development. Non-magnetic component development method; toner is transported to the developing section by electric field curtain method,
The toner obtained by the present invention, which is applicable to the electric field curtain development method used for development, particularly has a weight-average particle size of 2 to 811 mm, which requires a sharp particle size distribution. It can be preferably applied to a developing method using a toner with a small particle size of m.

Support 11 Hereinafter, the present invention will be explained in more detail based on Examples.

Styrene 90g 2-ethylhexyl methacrylate 10g 2.2'-Azobis-
2g (2,4-dimethylvaleronitrile) 2.2-7zobisisobutyronitrile 1g cyclized rubber (
Made by Hoechst Japan, 10g Alpex CK4
50) Charge-controlling organometallic complex 2g (Orient Chemical Acid, Bontron E-81) carbon black
12g (manufactured by Capot, Sterling R
) The above polymerizable monomer mixture was mixed using an attritor.
By mixing at 0°C, the monomer composition (viscosity at 60°C: 30
0 cps) was prepared. Next, 5 g of amino-modified silica (100 parts by weight of Aerosil #200 manufactured by Nippon Aerosil Co., Ltd. was reacted with 5 parts by weight of aminopropyltriethoxysilane), 600 g of distilled water, and 20 g of l/ION hydrochloric acid.
and using a circulating ultrasonic homogenizer (Nippon Seiki Seisakusho model, RUS-300), the frequency was 20 to 1 (z
A liquid dispersion medium was obtained by three passes at ±2 KHz and 0.41/min at an output of 800 W. This liquid dispersion medium was placed in a stainless steel container with a capacity of 2 liters.

Add the monomer composition prepared above and heat the TK at 60°C.
10.00O using a homomixer (Special Machinery Industry Department)
The mixture was granulated by stirring at rpm for 15 minutes.

The monomer composition thus granulated was polymerized using a paddle stirring blade at 60° C. for 10 hours.

The polymerized product obtained above was cooled and dehydrated, then washed with a sodium hydroxide solution, dehydrated, and dried to obtain a polymerized toner.

The particle size of the obtained toner was measured using a Coulter counter (aperture 1001LI1).

The volume average particle size of the toner is 6.571 m, and the particle size is 2.
The volume percentage of fine powder below 52μ is 6%, 10.0
The volume percentage of coarse powder of 81 Lm or more was 3%, which was an extremely narrow particle size distribution.

A monomer composition was prepared by mixing at 30°C.

Amino-modified silica (Aerosil #20 manufactured by Nippon Aerosil)
6 g (reacted with 5 parts by weight of aminopropyltriethoxysilane), 600 g of distilled water, and 22 g of 1/ION hydrochloric acid using a circulating ultrasonic homogenizer (Nippon Seiki Co., Ltd., RUS-300). ) and dispersed in the same manner as in Example 1 to obtain a liquid dispersion medium. The medium M body composition prepared above was added to a stainless steel container with a capacity of 2 volumes containing this liquid dispersion medium, and the mixture was heated at 60°C.
10,00 using K homo mixer (manufactured by Tokushu Kika Kogyo)
After granulation by stirring at 0 rpa+ for 60 minutes, the monomer composition was polymerized in the same manner as in Example 1.

The resulting polymerized product was cooled, dehydrated, washed with a sodium hydroxide solution, dehydrated, and dried to obtain a polymerized toner.

When the particle size of the obtained toner was measured with a Coulter counter (aperture 50 pLm), the volume average particle size of the toner was 5.5 μm, and the volume percentage of fine powder with a particle size of 2.52 gm or less was 3%, to, The volume percent of the coarse powder of 08JL 1m or more was 3%, which was an extremely narrow particle size distribution.

Qi M-body composition (60°C) by mixing at 30°C using
A viscosity of 300 cps) was prepared.

Next, 5 g of colloidal silica (Aerosil #200 manufactured by Nippon Aerosil Co., Ltd.) and 600 g of water were placed in a circulating ultrasonic homogenizer (RUS-300) and added to the liquid dispersion medium prepared above in the same manner as in Example 1. Add the monomer composition and mix using a TK homomixer at 10.00 Orp.
After granulation for 20 minutes at a temperature of 60° C., polymerization was carried out at 60° for 0.10 hours using a paddle blade stirring blade.

The resulting polymerized product was cooled and dehydrated, then washed with a sodium hydroxide solution, dehydrated, and dried to obtain a polymerized toner.

When the particle size of the obtained toner was measured using a Coulter counter (aperture 1001Lts), the volume average particle size was 6. The particle size distribution was extremely narrow, with the volume percent of fine powder having a particle size of 2.52 pL11 or less being 6%, and the volume percent of coarse powder having a particle size of 10°081 L or more being 3%.

A monomer composition (viscosity 100 cps at 80"C) was prepared by mixing at 30°C. Next, 5 parts by weight of aminopropyltriethoxysilane was added to 100 parts by weight of amine-modified silica (Aerosil #200 manufactured by Nippon Aerosil). 8g of the reaction mixture), 600g of distilled water, and 1/ION
20 g of hydrochloric acid using a circulating ultrasonic homogenizer (RUS-300, manufactured by Nippon Seiki Seisakusho) at a frequency of 20 K.
A liquid dispersion medium was obtained by dispersing at Hz±2KHz and an output of 300W for 20 minutes. Volume 2 containing this liquid dispersion medium
The monomer composition prepared above was added to a stainless steel container, and granulated by IW stirring at 12.00 Orpm for 10 minutes at 60°C using a TK homo mixer (Tokushu Kikako Bunka). The monomer composition was polymerized using a paddle stirring blade at 60° C. for 10 hours.

The resulting polymerized product was cooled and dehydrated, then washed with a sodium hydroxide solution, dehydrated, and dried to obtain a polymerized toner.

When the particle size of the obtained toner was measured using a Coulter Counter (aperture 1001 Lm), the volume average particle size was 5.5 gm, and the volume percentage of fine powder with a particle size of 2.52 pm or less was 6%, The volume percent of coarse powder was 3%, which was an extremely narrow particle size distribution.

Arashikasa 1 The amino-modified silica used in Example 1 was used in an amount of 10 g, and the dispersion stabilizer was not dispersed using an ultrasonic dispersion device, but the particles were dispersed for 60 minutes using a TK homomixer. A polymerized toner was obtained in the same manner as in Example 1.

The particle size of the obtained polymerized toner is such that the volume average particle size is 11, O
ILm, the volume percent of fine powder with a particle size of 6.35 gm or less is 15%, the volume percent I of coarse powder with a particle size of 16 p, m or more is 15%, and the particle size distribution is different from Example 1. It was spacious.

[Brief explanation of the drawing]

1 to 3 are schematic side sectional views showing an example of an ultrasonic irradiation device used in the dispersion process of the present invention, and FIGS. 4 to 7 show embodiments of the manufacturing method of the present invention. It is a process diagram. l... Container 2... Liquid dispersion medium 3... Vibrating body 4... Ultrasonic irradiation unit 5... Irradiation wall 6... Injection 1'' 7... Outlet f! ;;JLJIA: Figure 2 Figure 2■ Friends Figure 3

Claims (1)

[Claims] 1. A dispersion step in which a liquid dispersion medium containing a fine powder dispersion stabilizer is irradiated with ultrasonic waves to disperse the dispersion stabilizer; A granulation step of dispersing and suspending a monomer composition containing at least a polymerizable monomer and a colorant in a dispersion medium to granulate it; and suspension polymerization of the granulated monomer composition. 1. A method for producing a toner for developing an electrostatic image, the method comprising at least the following steps: a polymerization step for forming toner particles. 2. In the granulation step, the volume average particle diameter of the toner is 1 to 20.
2. The method for producing a toner for developing an electrostatic image according to claim 1, which comprises a granulation step of granulating the monomer composition to a particle size of .mu.m.