JPH0713760B2 - Toner manufacturing method - Google Patents

Description

The present invention relates to a method for producing a toner used in a method for developing a latent image.

[Prior Art] Toner for such a purpose is for forming and recording an image. For example, a large number of electrophotographic methods are known as described in U.S. Pat.No. 2,297,691 and the like, and generally, a photoconductive substance is used to form an electrophotographic image on a photoreceptor by various means. Latent image is formed, then the latent image is developed with toner, the toner image is transferred to a transfer member such as paper, if necessary, and then fixed by heating, pressure or solvent vapor to obtain a copy. . As a method of developing with a toner and a method of fixing, various kinds of methods have been conventionally proposed and used as needed.

Conventionally, as a toner used for these purposes, a coloring material such as magnetic powder, dye and pigment is generally melt-mixed in a thermoplastic resin and uniformly dispersed, and then a desired particle diameter is obtained by a fine pulverizer and a classifier. Has manufactured toner.

Although this method of manufacture can produce fairly good toners, it has certain limitations, ie, the choice of toner materials. For example, the resin colorant dispersion must be sufficiently brittle and pulverizable in an economically feasible manufacturing apparatus. From this requirement, since the resin colorant dispersion becomes brittle,
Actually, when finely pulverizing at a high speed, particles having a wide particle size range are likely to be formed, and there arises a problem that a relatively large proportion of fine particles is contained therein. Further, such highly brittle materials are often further comminuted or pulverized when used for development in copiers and the like. Further, in this method, it is difficult to completely uniformly disperse solid fine particles such as magnetic powder or a coloring agent in the resin,
Depending on the degree of the dispersion, it may cause an increase in fog and a decrease in the image density, so that attention must be paid to the dispersion. Further, the conductor such as a magnetic material is exposed on the fracture surface, which may make it difficult to manufacture the insulating toner.

On the other hand, in order to overcome the problems of the toner by the pulverization method, a method for producing the toner by the suspension polymerization method has been proposed. In the suspension polymerization method, a polymerizable monomer, a polymerization initiator and, if necessary, a crosslinking agent, a charge control agent, a magnetic material,
A toner having a desired particle size, in which a monomer system in which a colorant and other additives are uniformly dissolved or dispersed is dispersed in an aqueous phase containing a dispersion stabilizer by using a suitable stirrer and at the same time a polymerization reaction is performed. You are getting particles.

The toner thus obtained polymerizes the oil phase in the water phase,
The toner becomes substantially spherical. Since the spherical toner has a spherical shape, it has good fluidity and has a feature that the filling amount into the developing device is larger than that of the pulverized toner, but on the other hand, there is a problem that cleaning failure easily occurs. ing.

[Problems to be Solved by the Invention] An object of the present invention is to provide a method for producing a toner that solves the above problems.

The purpose of the present invention is high image density, a clear image is obtained,
An object of the present invention is to provide a method for producing a toner having good fixing properties and excellent developability. Further, another object of the present invention is to provide a method for producing a toner having good fluidity and causing no aggregation.

[Means and Actions for Solving Problems] The above object is achieved by the following configurations of the present invention.

The present invention is a method for producing a toner obtained by polymerizing a polymerizable monomer system in an aqueous phase, which is a fine particle toner obtained from a polymerizable monomer system containing hardly water-soluble inorganic fine particles having a particle size of 3 μm or less. An amorphous toner is obtained by adding a monomer system containing an initiator to a dispersion medium system containing the above to coalesce the fine particle toner, and further removing the hardly water-soluble inorganic fine particles on the surface portion by a chemical treatment. And a method for producing a toner.

The poorly water-soluble inorganic fine particles that can be used here have a particle size of 3 μm or less, preferably 0.1 to 2 μm, and are poorly water-soluble carbonates of metals other than alkali metals (solubilized by hydrochloric acid), for example, zinc carbonate, calcium carbonate, carbonic acid. Copper, magnesium carbonate,
Metals that react with hydrochloric acid to become water soluble, such as zinc and iron,
Examples thereof include metals that are solubilized by reacting with sodium hydroxide, such as zinc and aluminium, and metal halides that are solubilized by reacting with aqueous ammonia, such as silver chloride and silver bromide. These inorganic fine particles are present on the surface of the toner fine particles after the granulation step, and are also present on the surface portion even when they become toner particles through the coalescence step during the polymerization step. It is dissolved and removed by a step of treating with an aqueous solution of sodium oxide or aqueous ammonia. The addition amount of these poorly water-soluble inorganic fine particles depends on the monomer.
It is used in an amount of 1 to 50 parts by weight, preferably 5 to 20 parts by weight, based on 100 parts by weight.

The particle size of the toner particles before the coalescence step is 5 μm or less, preferably 1 to 3 μm.

In the coalescence step during the polymerization, the stirring is intensified to 2000 to 5000 rpm, preferably 2500 to 4500 rpm, and 1
After 6 hours, preferably after 2-4 hours. Further, the addition amount of the monomer system containing an initiator at this time is 1/100 to an equivalent amount, preferably 1/50 to 1/2 of the initial monomer system addition amount.

It is desirable that the amount of the monomer and the water during the polymerization be 300 to 3000 parts by weight of water with respect to 100 parts by weight of the monomer.
The polymerization temperature is set to 50 ° C or higher, generally 70 to 90 ° C, to carry out the polymerization. After the completion of the polymerization, the toner particles produced are collected by an appropriate method such as washing, filtration, decantation and centrifugation and dried.

The polymerizable monomer applicable to the present invention, styrene,
o-methylenestyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene,
p-ethylstyrene, 2,4-dimethylstyrene, pn
-Butylstyrene, p-tert-butylstyrene, pn
-Hexyl styrene, pn-octyl styrene, p-
n-nonylstyrene, pn-decylstyrene, pn
-Styrene and its derivatives such as dodecyl styrene;
Ethylenically unsaturated monoolefins such as ethylene, propylene, butylene and isobutylene; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride; vinyl esters such as vinyl acetate, vinyl propionate and vinyl benzoate. Kinds; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate,
Α-Methylene aliphatic monocarboxylic acid esters such as phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, acrylic Acid n
-Acrylic esters such as octyl, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether; vinyl Vinyl ketones such as methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; N-vinyl compounds such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole and N-vinyl pyrrolidone; vinyl naphthalene compounds; acrylonitrile, methacrylonitrile There are vinyl monomers such as acrylic acid or methacrylic acid derivatives such as nitrile and acrylamide.

Further, a polymer having a polar group, a copolymer or a cyclized rubber may be added as an additive at the time of polymerizing the monomer to polymerize the monomer.

In the present invention, a polymerizable monomer system containing a polymer having a polar group, a copolymer or a cyclized rubber at the time of polymerization is dispersed in an aqueous phase in which a dispersant having an opposite charge to the polar polymer is dispersed. It is preferable to suspend and polymerize. That is, the cationic or anionic polymer, copolymer, or cyclized rubber contained in the polymerizable monomer system is polymerized with the oppositely charged anionic or cationic dispersant dispersed in the aqueous phase. Electrostatically attracted to the surface of the particles to be the toner inside, and the dispersant covers the surface of the particles to prevent the particles from coalescing and stabilize, and the polar polymer added at the time of polymerization is added to the surface layer of the particles to be the toner. As they collect, they form a kind of shell-like shape, and the obtained particles become pseudo capsules. Using a relatively high molecular weight polar polymer, copolymer or cyclized rubber,
While giving the toner particles excellent properties such as blocking property, developing property, and abrasion resistance, by internally polymerizing so as to contribute to the improvement of fixing property with a relatively low molecular weight, the conflicting properties of fixing property and blocking property are obtained. It is possible to obtain a toner that satisfies the above requirements. The polar polymers (including polar copolymers) and the oppositely charged dispersants that can be used in the present invention are exemplified below.

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

(Ii) 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, and unsaturated dibasic acids. There are polymers of anhydrides and nitro monomers.

(Iii) As the anionic dispersant, a water-soluble polymer such as a partially saponified vinyl acetate polymer or Aerosil #
There are colloidal silicas such as 200, # 300 (made by Nippon Aerosil Co., Ltd.).

(Iv) Aluminum oxide as the cationic dispersant,
There are fine powders of hydrophilic positively charged silica such as magnesium hydroxide and aminoalkyl-modified colloidal silica. Cyclized rubber may be used instead of the polar polymer.

As the magnetic particles that can be used in the present invention, substances that are magnetized by being placed in a magnetic field are used. For example, powders of ferromagnetic metals such as iron, cobalt and nickel or magnetite,
Examples include powders of alloys and compounds such as hematite and ferrite. Particle size is 0.05-5 μm, preferably 0.1-1 μm
Magnetic fine particles of m are used. The content of the magnetic particles is 10 to 60% by weight, preferably 25 to 60% by weight based on the weight of the toner.
50% by weight is good. Further, these magnetic fine particles may be treated with a treating agent such as the above-mentioned silane coupling agent or titanium coupling agent, or an appropriate reactive resin. In this case, although depending on the surface area of the magnetic fine particles and the density of hydroxyl groups existing on the surface, sufficient dispersibility is obtained with a treatment amount of 5% or less, and the physical properties of the toner are not adversely affected.
A charge control agent, a colorant, and a fluidity modifier may be added to the toner as needed. The charge control agent and the fluidity modifier may be used as a mixture (external addition) with toner particles. As the charge control agent, there are metal-containing dyes, nigrosine and the like, as the colorant, conventionally known dyes and pigments can be used, and as the fluidity modifier, there are colloidal silica and fatty acid metal salts. Further, for the purpose of increasing the amount, a filler such as calcium carbonate or fine powder silica may be blended in the toner in the range of 0.5 to 20% by weight. Further, in order to prevent aggregation of the toner particles and improve fluidity, a fluidity improver such as Teflon fine powder may be added. Further, for the purpose of improving the releasability at the time of fixing with a hot roll, waxes generally used as a releasing agent such as hydrocarbon compounds and carnauba wax may be added to the toner.

The hydrocarbon compound used in the present invention includes paraffins and polyolefins having carbon atoms of ₆ or more, such as paraffin wax (manufactured by Nippon Oil Co., Ltd.), paraffin wax (manufactured by Nippon Seiro Co., Ltd.), microwax (manufactured by Nippon Oil Co., Ltd.), Microcrystalline Wax (made by Nippon Seiro Co., Ltd.), PE-130
(Made by Hoechst), Mitsui High Wax 110P (manufactured by Mitsui Petrochemical), Mitsui High Wax 220P (manufactured by Mitsui Petrochemical), Mitsui High Wax 660P (manufactured by Mitsui Petrochemical), and the like, with low molecular weight polyethylene and low molecular weight being particularly preferred. Polypropylene and paraffin.

As the polymerization initiator, any suitable polymerization initiator, for example, azobisisobutyronitrile (AIBN), benzoyl peroxide, methyl ethyl ketone peroxide, isopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorolyl benzoyl peroxide is used. Oxides, lauroyl peroxide, etc. can be used to polymerize the monomers. Generally, about 0.5-5% by weight of the monomer of initiator is sufficient.

At the time of polymerization, the following crosslinking agent is present for polymerization,
It may be a cross-linked polymer.

Divinylbenzene, divinylnaphthalene, divinyl ether, divinyl sulfone, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butylene glycol dimethacrylate , 1,6-
Hexane glycol dimethacrylate, neopentyl glycol dimethacrylate, dipropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, 2,2'-bis (4-methacryloxydiethoxyphenyl) propane, 2,2'-bis (4-acryloxy) Diethoxyphenyl) propane, totimethylol propane trimethacrylate, trimethylol propane triacrylate, tetramethylol methane tetraacrylate, dibromoneopentyl glycol dimethacrylate, allyl phthalate, 1,2-propylene glycol, 1,3
-General cross-linking agents such as butanediol can be used as appropriate.

If these crosslinking agents are used in a large amount, they will not dissolve and the fixing will be poor. If the amount used is small, properties such as blocking resistance and durability required as a toner deteriorate, and during heat roll fixing, part of the toner adheres to the roller surface without completely sticking to the paper, It becomes difficult to prevent the offset phenomenon of transfer. Therefore, the amount of these cross-linking agents used is 0.
It is preferable to use 001 to 15% by weight (more preferably 0.1 to 10% by weight).

Suitable dispersion media used in the present invention include, for example, any suitable stabilizer, such as polyvinyl alcohol,
Gelatin, methyl cellulose, methyl hydropropyl cellulose, ethyl cellulose, sodium salt of carboxymethyl cellulose, polyacrylic acid and salts thereof, starch, gum alginate, zein, casein,
By using any one or a mixture of tricalcium phosphate, talc, barium sulfate, bentonite, aluminum hydroxide, ferric hydroxide, titanium hydroxide, sodium hydroxide, etc. in an aqueous phase. Is also good. The stabilizer is a stabilizing amount in the continuous phase, preferably about 0.1-10.
Used within the range of weight%. It is also possible to use a surfactant in the range of 0.001 to 0.1% by weight for finely dispersing the inorganic dispersant. This is for promoting the intended action of the above dispersion stabilizer, and specific examples thereof include sodium dodecylbenzenesulfonate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, and allyl-alkyl-poly. Sodium ether sulfonate, sodium oleate, sodium laurate, sodium caprate, sodium caprylate, sodium caproate, potassium stearate, calcium oleate, 3,3-disulfone diphenylurea-4,4-diazo-bis-amino -8-Naphthol-6-sulfonate sodium, ortho-carboxybenzene-azo-dimethylaniline, 2,2,5,5-tetramethyl-triphenylmethane-4,4-diazo-bis-β-
Naphthol-sodium disulfonate and the like can be mentioned.

Further, a water-soluble monomer simultaneously undergoes emulsion polymerization in water and contaminates the resulting suspension polymer with small emulsion-polymerized particles.Therefore, a water-soluble polymerization inhibitor, such as a metal salt, is added to the suspension to form an aqueous phase. It is also good to prevent emulsion polymerization. In addition, glycerin, glycol or the like may be added to water in order to increase the viscosity of the medium and prevent the particles from coalescing. It is also possible to use salts such as NaCl, KCl and Na ₂ SO ₄ in order to reduce the solubility of the easily soluble monomer in water.

[Examples] Hereinafter, the present invention will be described in detail based on Examples.

Example 1 The above formulation was heated to 70 ° C. in a container, dissolved, and dispersed. Mix the dispersion obtained in a container equipped with a TK homomixer (manufactured by Tokushu Kika Kogyo) having a high shear force for about 5 minutes while maintaining the temperature at 70 ° C. 6 g of ronitrile was added and dissolved to prepare a monomer system.

Separately, a 2 liter flask containing an aqueous dispersion liquid in which 4 g of Aerosil 200 (manufactured by Nippon Aerosil Co., Ltd.) was dispersed was heated to 70 ° C., the above monomer system was charged, and the mixture was stirred at 10,000 rpm for 20 minutes. Further, the mixture was stirred at a low rotation speed of 200 rpm. The particle size at this time was in the range of 1 to 3 μm as observed by an optical microscope. After 3 hours from the start of the reaction, stirring was increased to 4,000 rpm, and styrene / n-butyl methacrylate =
Initiator azobisisobutyronitrile = 17/3 monomer system
50 g of the mixed system heated to 70 ° C. in the ratio of 6 was added, and high speed stirring was performed for 20 minutes. After that, the rotation speed was lowered to a low speed to complete the polymerization.

After removing the dispersant, washing with water and washing with water, further washing was carried out under acidic conditions with hydrochloric acid to dissolve and remove zinc carbonate present on the surface of the particles, and washing with water and drying were carried out to obtain a toner. The obtained toner particles had an average particle size of 11 μm, and the particle morphology was observed by an electron microscope.

To 100 g of this toner, 0.4 g of Nipsyl ER (manufactured by Nippon Silica) was added to prepare a developer. Commercially available copying machine PC-20 (made by Canon)
At, when images were printed using a copying machine in which the cleaning plate pressure was set to 80% of normal, a good image was obtained, no cleaning failure occurred, and the offset property,
The fixability was also good. Also, the same thing was observed in the durability test of 3,000 sheets, and neither deterioration in image quality nor density was observed.

Comparative Example 1 In Example 1, a system in which zinc carbonate powder was not added was
Polymerization was carried out at 0 rpm / 20 minutes and further completed at a low rotation speed of 200 rpm to obtain a substantially spherical toner having an average particle size of 11 μm. When toner formation and image formation were performed in the same manner as in Example 1, cleaning failure occurred from the second sheet.

Example 2 The above formulation was heated to 70 ° C. in a container to dissolve / disperse it. This is mixed for about 5 minutes in a container equipped with a mixing device having high shearing force such as TK homomixer (made by Tokushu Kika Kogyo) while maintaining at 70 ° C., and 6 g of azobisisobutyronitrile is further added. Added and dissolved.

On the other hand, silica that has been previously treated with aminoalkylsilane in water
A 2 liter flask containing 10 g dispersed therein was heated to 70 ° C., charged with the above monomer system, and stirred at 10,000 rpm for 20 minutes. Further, the mixture was stirred at a low rotation speed of 200 rpm. The particle size at this time was in the range of 1 to 3 μm as observed by an optical microscope. After 4 hours from the start of the reaction, stirring was increased to 5000 rpm, and styrene / 2-ethylhexyl methacrylate /
Cyclized rubber CK-450 / azobisisobutyronitrile 15/5/2 /
20 g of the system which was heated and mixed at 70 ° C. at a ratio of 0.6 was added, and high speed stirring was performed for 20 minutes. After that, the rotation speed was returned to a low speed to complete the polymerization.

After removing the dispersant, washing with water and washing with water, further washing was carried out under acidic condition with hydrochloric acid to dissolve and remove calcium carbonate existing on the surface of the particles, and washing with water and drying were carried out to obtain a toner. The obtained toner had an average particle size of 10 μm, and the particle morphology was observed by an electron microscope. As a result, the toner had different shapes.

To 100 g of this toner, 0.4 g of Talanox 500 (Tarco Co.) was added to obtain a developer. When a commercial copying machine NP-270RE (manufactured by Canon) was used to print an image using a copying machine with the cleaning plate pressure set to 80% of the normal level, it was a good image, no cleaning defects occurred, and offset And the fixability were also good. Also, the same thing was observed in the durability test of 3,000 sheets, and neither deterioration in image quality nor density was observed.

Comparative Example 2 7,00 without adding calcium carbonate powder in Example 2
Polymerization was carried out at 0 rpm for 20 minutes and further completed at a low rotation speed of 200 rpm to obtain a substantially spherical toner having an average particle size of 10 μm. When toner formation and image formation were performed in the same manner as in Example 2, cleaning failure occurred from the second sheet.

[Advantages of the Invention] As described above, according to the production method of the present invention, a toner having good fluidity, no agglomeration, good fixing characteristics and excellent developability, and high image density, A clear image can be obtained.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshihiko Yoshihiko 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) Reference JP-A-60-220358 (JP, A) JP-A Sho 56-128957 (JP, A) JP-A-58-211162 (JP, A)

Claims (1)

[Claims] 1. A method for producing a toner obtained by polymerizing a polymerizable monomer system in an aqueous phase, comprising fine particles obtained from a polymerizable monomer system containing hardly water-soluble inorganic fine particles having a particle size of 3 μm or less. After adding the monomer system containing the initiator to the dispersion medium system containing the toner and coalescing the fine particle toner, further removing the hardly water-soluble inorganic fine particles on the surface portion by a chemical treatment to give an irregular shape. A method for producing a toner, which comprises obtaining a toner.