JPH0777835A - Production of polymer toner - Google Patents

Abstract

PURPOSE:To obtain a producing method of a polymer toner having good fixing property, excellent developing property, and cleaning property with which a sharp image with high density can be obtd. by applying shearing force and compressive force to specified polymer particles by using in-line screws to produce particles of various shapes. CONSTITUTION:A polymerizable monomer oil phase is suspended and polymerized in a water phase to prepare a suspension liquid containing substantially spherical polymer particles. During the polymn. rate of the suspension liquid ranges 85-97 %, shearing force and compressive force is given to the liquid by using an in-line screw pump to produce continuously or in batch process particles of various shapes. As for the polymerizable monomers to constitute the polymerizable monomer system to be used for the polymer toner and an additive such as a coloring agent to give toner characteristics, stylene, o- methylstylene, or m-methylstyrene are used. The in-line screw pump used for the production of the polymer toner is preferably a pump having 1-4 compression rate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polymerized toner used for developing a latent image.

[0002]

BACKGROUND OF THE INVENTION Electrophotography is described in U.S. Pat. No. 2,297,6.
As described in Japanese Patent No. 91, etc., a large number of methods are known. Generally, a photoconductive substance is used to form an electric latent image on a photoreceptor by various means, and then the latent image is formed. The image is developed with toner and, if necessary, the toner image is transferred to a transfer member such as paper and then fixed by heating, pressure, solvent vapor or the like to obtain a copy. Further, as a method of developing with toner or a method of fixing a toner image,
Conventionally, various methods have been proposed, and methods suitable for respective image forming processes have been adopted.

Conventionally, toners used for these purposes are generally toners having a desired particle size by a fine pulverizer and a classifier after melt-mixing a colorant consisting of dyes and pigments in a thermoplastic resin and uniformly dispersing them. Has been manufactured.

While this method of manufacture can produce fairly good toners, it does have certain limitations, ie, the choice of toner materials. For example, the resin colorant dispersion is sufficiently brittle,
It must be able to be milled with economically feasible manufacturing equipment. However, if the resin colorant dispersion is made brittle in order to satisfy these requirements, the particle size range of the particles formed when actually pulverized at a high speed tends to be wide, and particularly a relatively large proportion of fine particles is The problem of inclusion arises. Furthermore, such a brittle material is likely to undergo further fine pulverization or pulverization when used for developing such as a copying machine. Further, in this method, it is difficult to completely and uniformly disperse solid fine particles such as a colorant in the resin. Depending on the degree of dispersion, fog increases, image density decreases, and color mixing / transparency decreases. Care must be taken in dispersion as it causes defects. In addition, the exposure of the colorant on the fracture surface may cause fluctuations in the developing characteristics.

On the other hand, in order to overcome the problems of toner by the pulverization method, Japanese Patent Publication Nos. 36-10231 and 43-43
A method for producing a toner by a suspension polymerization method has been proposed by 10799 and 51-14895. In the suspension polymerization method, a polymerizable monomer, a colorant, a polymerization initiator and, if necessary, a crosslinking agent, a charge control agent, and other additives are uniformly dissolved or dispersed to obtain a monomer composition. , A continuous phase containing this monomer composition containing a dispersion stabilizer,
For example, it is dispersed in an aqueous phase using a suitable stirrer, and at the same time, a polymerization reaction is carried out to obtain toner particles having a desired particle size.

Since the toner thus obtained polymerizes the oil phase in the aqueous phase, it becomes a substantially spherical toner. Since the spherical toner has a spherical shape, it has a good fluidity, and has a feature that the amount filled in the developing machine is larger than that of the pulverized toner. However, on the other hand, it has a problem that cleaning failure is likely to occur.

As a method for overcoming this problem, for example, JP-A-62-266560 and JP-A-2-1324.
No. 58, No. 132460, No. 256068, etc. have been proposed, but all of them are disadvantageous in manufacturing due to complicated processes.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a polymerized toner which solves the above problems.

An object of the present invention is to provide a method for producing a polymerized toner having a high image density, a clear image, a good fixing property and an excellent developing property. Further, it is an object of the present invention to provide a method for producing a polymerized toner which is excellent in blade cleaning property and has good productivity while having good fluidity and resistance to aggregation.

[0010]

To achieve the above object, according to the present invention, there is provided a method for producing a toner obtained by suspension polymerization of a polymerizable monomer in an aqueous phase, A method for producing a toner is proposed, in which a shearing force and a compressing force are applied at the same time when the polymerization rate of the polymer particles is in the range of 85% to 97% to make the particles indefinite.

According to the present invention, such a toner is prepared by subjecting a polymerizable monomer oil phase to suspension polymerization in an aqueous phase to prepare a suspension containing substantially spherical polymer particles, and the polymerization rate thereof is 85 to 85. 97
By applying shear and compression forces to the suspension with an in-line screw pump in the range of%, it is possible to make such particles amorphous in batches or continuously.

The toner according to the present invention and the method for producing the same will be described below.

Examples of the polymerizable monomer constituting the polymerizable monomer system used in the present invention and the toner property imparting agent such as a colorant include the following.

Examples of the polymerizable monomer include styrene-based monomers such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene and p-ethylstyrene, methyl acrylate and acryl. Ethyl acetate, n-butyl acrylate, isobutyl acrylate, n-propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, etc. Acrylic esters, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, methacrylic acid Phenyl, dimethylaminoethyl methacrylate, methacrylic acid esters other acrylonitrile such as ethyl methacrylate aminoethyl, methacrylonitrile, and the like monomers acrylamide.

These monomers may be used alone or as a mixture. Among the above-mentioned monomers, it is preferable to use styrene or a styrene derivative alone or in combination with other monomers, from the viewpoint of developing characteristics and durability of the toner.

In the present invention, a resin having a polar group may be added to the monomer system for polymerization. The polar resins that can be used in the present invention are exemplified below.

Examples of the cationic polymer (1) include polymers of nitrogen-containing monomers such as dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate, and copolymers with styrene and unsaturated carboxylic acid esters. .

(2) Examples of the anionic polymer include nitrile monomers such as acrylonitrile, halogen-containing monomers such as vinyl chloride, unsaturated carboxylic acids such as acrylic acid and methacrylic acid, and other unsaturated dibases. Examples thereof include acid / unsaturated dibasic acid anhydrides, polymers such as nitro monomers, and copolymers with styrene monomers.

These polar resins localize near the surface of the toner to improve the blocking resistance of the toner. The addition amount is preferably 0.1 to 10% by weight.

As the colorant used in the present invention, known colorants can be used. For example, carbon black, iron black, C.I. I. Direct Red 1, C.I. I. Direct Red 4, C.I. I. Acid Red 1, C.I. I. Basic Red 1, C.I. I. Mordant Red 30, C.I.
I. Direct Blue 1, C.I. I. Direct Blue 2, C.I. I. Acid Blue 9, C.I. I. Acid Blue 15, C.I. I. Basic Blue 3, C.I. I. Basic Blue 5, C.I. I. Mordant Blue 7, C.I. I.
Direct Green 6, C.I. I. Basic Green 4, C.I. I. Dyes such as basic green 6, yellow lead, cadmium yellow, mineral fast yellow, navel yellow, naphthol yellow S, Hansa yellow G, permanent yellow NCG, tartrazine lake, molybdenum orange, permanent orange GT
R, benzidine orange G, cadmium red, permanent red 4R, watching red calcium salt,
Brilliant Carmine 3B, Fast Violet B,
There are pigments such as methyl violet lake, dark blue, cobalt blue, alkali blue lake, Victoria blue lake, quinacridone, rhodamine lake, phthalocyanine blue, fast sky blue, pigment green B, malachite green lake, and final yellow green G. In the present invention, since the toner is obtained by using the suspension polymerization method, it is necessary to pay attention to the polymerization inhibitory property and the water phase transfer property of the colorant, and preferably surface modification, for example, a substance without polymerization inhibitory property. It is better to give a hydrophobic treatment by. In particular, since many dyes and carbon black have a polymerization inhibitory property, caution is required when using them. As a preferred method of surface-treating a dye system,
A method of polymerizing a polymerizable monomer in the presence of these dyes in advance is mentioned, and the obtained colored polymer is added to the monomer system. Further, the carbon black may be subjected to the same treatment as the above-mentioned dye, or to a graft treatment with a substance that reacts with the surface functional group of the carbon black, for example, polyorganosiloxane.

When the toner is used as a magnetic toner, it may contain magnetic powder. As such magnetic powder, a substance that is magnetized when placed in a magnetic field is used.
There are powders of ferromagnetic metals such as iron, cobalt and nickel, and compounds such as magnetite and ferrite. In particular, in the present invention, since the toner is obtained by using the polymerization method, it is necessary to pay attention to the polymerization inhibitory property and the water phase transfer property of the magnetic material, and preferably the surface modification, for example, there is no polymerization inhibitory property. It is better to give a hydrophobic treatment with a substance.

In the present invention, for the purpose of improving releasability at the time of heat roll fixing, a wax such as a hydrocarbon compound generally used as a releasing agent may be added to the toner. Examples of waxes used in the present invention include paraffin / polyolefin waxes and modified products thereof, such as oxides and graft-treated products, higher fatty acids, metal salts thereof, and amide waxes. These waxes have a softening point of 40 to 130 ° C., preferably 50 to 120, according to the ring and ball method (JIS K2531).
C. is desirable, and if the softening point is lower than 40.degree. C., the toner has insufficient blocking resistance and shape retention,
If the temperature exceeds 130 ° C, the effect of releasability becomes insufficient. The amount of these release agents added is preferably 0.1 to 50% by weight.

In the present invention, it is desirable to add a charge control agent to the toner material in order to control the chargeability of the toner. As these charge control agents, among known ones, those having almost no polymerization inhibitory property / water phase transfer property are used. For example, as a positive charge control agent, a nigrosine dye, a triphenylmethane dye, a quaternary ammonium salt, an amine is used. Examples of the negative charge control agent include metal-containing salicylic acid compounds, metal-containing monoazo dye compounds, styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers, and the like. The addition amount of these charge control agents is preferably 0.1 to 10% by weight.

As the polymerization initiator, any suitable polymerization initiator, for example, 2,2'-azobis- (2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1, 1'-azobis (cyclohexane-1-
Carbonitrile), 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile and other azo or diazo polymerization initiators; benzoyl peroxide, methyl ethyl ketone peroxide,
Examples thereof include peroxide-based polymerization initiators such as diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide and lauroyl peroxide. The amount of these polymerization initiators added is preferably 0.5 to 20% by weight of the polymerizable monomer.

In the present invention, a crosslinking agent may be added, and the preferable addition amount is 0.001 to 15% by weight.

The additives used in the present invention for imparting various characteristics are, from the viewpoint of durability when added to the toner,
The particle diameter is preferably 1/10 or less of the weight average diameter of the toner particles. The particle size of the additive means the average particle size thereof obtained by observing the surface of the toner particles with an electron microscope. As the additives for imparting these characteristics, for example, the following ones are used.

1) Flowability-imparting agents: metal oxides (silicon oxide, aluminum oxide, titanium oxide, etc.), carbon black, carbon fluoride, etc. Those subjected to a hydrophobic treatment are more preferable.

2) Abrasive: metal oxide (strontium titanate, cerium oxide, aluminum oxide, magnesium oxide, chromium oxide, etc.), nitride (silicon nitride, etc.), carbide (silicon carbide, etc.), metal salt (calcium sulfate, etc.) , Barium sulfate, calcium carbonate, etc.) etc.

3) Lubricants: Fluorine-based resin powders (vinylidene fluoride, polytetrafluoroethylene, etc.), fatty acid metal salts (zinc stearate, calcium stearate, etc.), etc.

4) Charge controllable particles: metal oxides (tin oxide, titanium oxide, zinc oxide, silicon oxide, aluminum oxide, etc.), carbon black, etc.

These additives are used in an amount of 0.1 to 10 parts by weight with respect to 100 parts by weight of toner particles, and preferably,
0.1-5 parts by weight are used. These additives may be used alone or in combination.

The aqueous medium used in the present invention includes:
Any suitable stabilizer is added. For example, as the inorganic compound, calcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide,
Examples thereof include aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica and alumina. As the organic compound, polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, ethyl cellulose, sodium salt of carboxymethyl cellulose, polyacrylic acid and its salt, starch and the like can be dispersed in an aqueous phase and used. This stabilizer is based on 100 parts by weight of the polymerizable monomer,
It is preferred to use 0.2 to 20 parts by weight.

For fine dispersion of these stabilizers, 0.001 to 0.1 part by weight of surfactant may be used. This is for promoting the intended action of the dispersion stabilizer, and specific examples thereof include sodium dodecylbenzene sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate,
Examples thereof include sodium oleate, sodium laurate, potassium stearate, calcium oleate and the like.

When an inorganic compound is used among these dispersion stabilizers, a commercially available product may be used as it is, but in order to obtain finer particles, the inorganic compound may be produced in an aqueous medium.

For example, in the case of calcium phosphate, it is advisable to mix the sodium phosphate aqueous solution and the calcium chloride aqueous solution under high stirring.

The polymerized toner used in the present invention is obtained by the following method. That is, a releasing agent, a colorant, a charge control agent, a polymerization initiator and other additives are added to the polymerizable monomer, and a monomer system uniformly dissolved or dispersed by a homogenizer / ultrasonic disperser, It is dispersed in an aqueous medium containing a dispersion stabilizer by a usual stirrer, homomixer / homogenizer or the like. Granulation is preferably carried out by adjusting the stirring speed and time so that the monomer droplets have a desired toner particle size, generally 30 μm or less. After that, by the action of the dispersion stabilizer, the particle state is maintained,
In addition, stirring may be performed to the extent that settling / floating of particles is prevented. Polymerization temperature is 40 ° C or higher, generally 50 to 90 ° C
Polymerization is performed by setting the temperature to. In addition, the temperature may be raised in the latter half of the polymerization reaction, and further in the latter half of the reaction or the end of the reaction in order to remove unreacted polymerizable monomers and by-products that may cause odor during toner fixing. The aqueous medium may be partially distilled off later.

Then, after preparing a suspension containing such substantially spherical polymer particles, the suspension is introduced into an in-line screw pump as it is, and shearing force and compressive force are simultaneously applied by its rotation to make it amorphous. The toner according to the present invention can be obtained.

The in-line screw pump used in the present invention may be a known one as shown in FIG.
A compression ratio of 1 to 4 is suitable.

If the compression ratio is less than 1, the irregularizing treatment is not sufficient, and if it exceeds 4, the polymer particles are crushed or fused and desired polymer particles cannot be obtained.

In addition, the in-line screw pump L /
D (screw length / screw diameter ratio) is preferably 20.

Furthermore, if necessary, the in-line screw pump may be equipped with a temperature adjusting mechanism.

The particle size distribution measurement in the present invention will be described.

A Coulter counter T is used as a measuring device.
A-II type (manufactured by Coulter, Inc.)
Interface that outputs volume average distribution (made by Nikkaki)
And CX-1 personal computer (Canon)
Connected to the electrolyte using 1% sodium chloride using primary sodium chloride.
An aqueous Cl solution is prepared.

As a measuring method, the electrolytic aqueous solution 100 to 1 is used.
To 50 ml, 0.1 to 5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant, and 0.5 to 50 mg of a measurement sample is further added.

The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment for about 1 to 3 minutes by an ultrasonic disperser, and a particle size distribution of particles of 2 to 40 μm is obtained by the Coulter Counter TA-II type using an aperture of 100 μm as an aperture. Is measured to obtain a volume average distribution and a number average distribution. The weight average particle diameter is obtained from the volume average distribution and the number average distribution thus obtained.

The toner according to the present invention can be obtained by subjecting the toner to irregular shape followed by washing and drying.

The present invention will be specifically described below based on Examples and Comparative Examples.

[0048]

Example 1 To 709 g of ion-exchanged water, 451 g of 0.1 M Na ₃ PO ₄ aqueous solution was added and heated to 60 ° C., and then 12,000 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo). It was stirred at. A 1.0 M-CaCl ₂ aqueous solution 67.
7 g was gradually added to obtain an aqueous medium containing Ca ₃ (PO ₄ ) ₂ .

Styrene 175 g 2-ethylhexyl acrylate 25 g C.I. I. Pigment Blue 15: 3 10 g Paraffin wax (mp 70 ° C.) 30 g Di-tert-butylsalicylic acid metal compound 5 g

The above formulation was heated to 60 ° C. and 12,000 rpm using a TK type homomixer (made by Tokushu Kika Kogyo).
Were uniformly dissolved and dispersed. In addition to this, a polymerization initiator, 2,
2'-azobis (2,4-dimethylvaleronitrile) 1
0 g and 1 g of dimethyl 2,2′-azobisisobutyrate were dissolved to prepare a polymerizable monomer system. The polymerizable monomer system was added to the aqueous medium, and the mixture was subjected to 10,000 r with a TK homomixer at 60 ° C. under N ₂ atmosphere.
The polymerizable monomer system was granulated by stirring at pm for 20 minutes. Then, while stirring with a paddle stirring blade, the reaction was carried out at 60 ° C. for 3 hours, then the liquid temperature was adjusted to 80 ° C., and the reaction was carried out for 10 hours.

Then, the suspension containing polymer particles was introduced into an in-line screw pump as shown in FIG.
Treated with a flow rate of 0 liters. The compression ratio of this in-line screw was 1 and L / D was 20. Then, the mixture was cooled and hydrochloric acid was added to dissolve Ca ₃ (PO ₄ ) ₂ , followed by filtration, washing with water and drying to obtain a polymerized toner. The particle size of the obtained toner was 8.5 μm in weight average diameter, had a sharp particle size distribution, and was indefinite by microscopic observation.

B was added to 100 parts by weight of the obtained toner.
0.7 part by weight of hydrophobic silica having a specific surface area of 200 m ² / g according to the ET method was externally added. To 7 parts by weight of this toner, 93 parts by weight of an acrylic-coated ferrite carrier was mixed to obtain a developer.

Using this developer and the externally added toner, images were printed by a full color copying machine CLC-500 modified by Canon. The results are shown in Table 1.

Comparative Example 1 Polymerized toner was obtained in the same manner as in Example 1, except that the compression ratio of the in-line screw was 0.8. The particle diameter of the obtained toner was 8.5 μm, and the shape was almost spherical. The results are shown in Table 1.

Example 2 A polymerized toner was obtained in the same manner as in Example 1 except that the compression ratio of the in-line screw was changed to 4. The particle diameter of the obtained toner was 9.1 μm in weight average diameter, and the shape was irregular. The results are shown in Table 1.

Comparative Example 2 A polymerized toner was obtained in the same manner as in Example 1, except that the compression ratio of the in-line screw was 4.5. The particle diameter of the obtained toner is 10.9 μm in weight average diameter.
In addition, a large number of fused and pulverized products were observed by microscopic observation (200 times). The results are shown in Table 1.

[0057]

[Table 1]

[0058]

As described above, since the toner according to the present invention is formed into an irregular shape from a substantially spherical shape, it does not remain on the surface of the photoconductor during cleaning with the blade and thus does not remain. Since it is almost completely removed, it provides a high quality copy image with excellent cleaning properties.

[Brief description of drawings]

FIG. 1 is a schematic explanatory diagram of an in-line screw pump that can be suitably used in the toner particle indefinite process of the present invention.

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Koji Inaba 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Kazuya Kazuya 3-30-2 Shimomaruko, Ota-ku, Tokyo Non non corporation

Claims (2)

[Claims] 1. The polymerization rate obtained by suspension polymerization is 85 to 97.
% Of polymer particles are subjected to simultaneous shearing force and compression force by an in-line screw to make the particles amorphous. 2. The compression ratio of the in-line screw is 1 to 1.
4. The method for producing a polymerized toner according to claim 1, wherein the number is 4.