JPS59123851A - Manufacture of toner - Google Patents

Abstract

PURPOSE:To improve the developing power and moisture resistance by treating a polymer obtd. by suspension polymn. with an alkali to remove hydrophilic inorg. matter sticking to the surface of the polymer for a toner. CONSTITUTION:A monomer system contg. a polymerizable monomer, a cationic polymer and a hydrocarbon compound is suspended in a dispersion medium contg. an inorg. anionic dispersant, and they are polymerized. The resulting polymer is charged into an aqueous soln. contg. a strong alkali by >=1%, preferably >=4% of the amount of the polymer, and inorg. matter on the surface of the polymer is reacted with the alkali and removed from the surface. Potassium hydroxide, sodium hydroxide, calcium hydroxide, tetramethylammonium hydroxide, ammonium carbonate, potassium carbonate, sodium carbonate or the like is used as the alkali.

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing toner.

Conventionally, toner is generally produced by melt-mixing colorants and other additives in a thermoplastic resin, uniformly dispersing the mixture, and then passing through a pulverizer 2.
A classifier has been used to produce toner having a desired particle size. Although this manufacturing method can produce slightly superior toner,
There are certain food restrictions. That is, toners obtained using the crushing force method must be brittle to make the material somewhat susceptible to crushing. However, if the toner has a high degree of brittleness, it will be pulverized too much, and in order to obtain a toner with an appropriate particle size distribution, it will be necessary to cut the toner into fine powder which is not worth it, which will increase the cost. Furthermore, in some cases, the toner is further pulverized in the developing device of a copying machine. Furthermore, when a material with a low melting point is used to improve heat fixability, a fusion phenomenon occurs in a crushing device or a classification device, and continuous production may not be possible. Other requirements for the toner are f) it has triboelectric properties suitable for lfJI, it forms a trailing image, there is no change in performance on standing, it does not solidify (blocking, etc.), it has suitable heat Alternatively, it must have pressure fixing properties and not contaminate the surface of the photoreceptor. Particularly during fusing, there is always an offset phenomenon in which toner adheres to the fusing roller and is retransferred onto the next copy paper. L! :&, and in order to prevent this, the fixing roller has been coated with a release agent such as silicone oil. However, in recent years, a method has become common to prevent offset by incorporating polypropylene or polyethylene 7'fl (D polyolefin) into the toner and not applying a delamination agent to the fixing roller.However, this method does not prevent offset. Due to the lack of sufficient effectiveness, it is not possible to make large quantities of copies without the necessary maintenance of an auxiliary fixing roller cleaning device.

Therefore, attempts were made to add a larger amount of polyolefin or to use a polyolefin with a much lower melting point. Blocking is performed to release the viscosity, resulting in poor fluidity and significantly lowering developability.

Therefore, in order to overcome the drawbacks of the pulverization method, a method for producing toner using a suspension polymerization method was proposed.

That is, since it does not involve any crushing process, it is not necessarily brittle, and because it is spherical, it has excellent fluidity, and therefore friction and charging are uniform. However, it is technically difficult to carry out polymerization with stably suspended threads without coalescence, and to obtain fine polymer particles with a uniform particle size distribution through polymerization. When suspension polymerizing the system in water,
Suspension stabilizers are used to prevent coalescence of the polymer particles as the polymerization progresses. Generally, suspension stabilizers include poorly soluble, finely powdered inorganic compounds, such as Ba so41 Ca.
804 t MgCO3, B a COJ *CaCO
5. Slightly soluble salts such as Cas (P 04 )t +, diatomaceous earth, talc, silicic acid, clay, inorganic polymers such as talc, powders of metal oxides, water-soluble polymers such as polyvinyl alcohol, gelatin, starch and so on.

Further, stirring also affects the stability of polymerization and the size of particles. High-speed stirring stabilizes polymerization, but the particles become smaller than necessary.

On the other hand, if the mixture is stirred at low speed, it may gel and particles may not be obtained. Therefore, it is necessary to choose appropriate conditions.

However, even with these methods, it is difficult to obtain toner particles with a satisfactory particle size, that is, fine particles with a number average diameter of about 10 to 20 μm. This is because, in the end, there are not enough ways to prevent union.

Therefore, in the combination of a polymerizable monomer and an inorganic dispersant, the interface of the polymerizable monomer particles is cationically charged by the addition of a cationic polymerizable monomer or a poorly water-soluble organic amine compound; , the inorganic dispersant is charged with an anion opposite to that of the polymerizable monomer particles, so that the inorganic dispersant completely and uniformly covers the surface of the polymerizable monomer particles through strong ionic bonds and coalesces. The number average diameter is 10.
A method for obtaining fine particles of about 20 μm has been proposed. However, even with this method, the particle size cannot be said to be sufficiently satisfactory as a toner. This is because it is more preferable that the toner particle size distribution is narrower. In other words, when the particle size becomes uniform, the amount of charge on each particle becomes almost the same, and therefore a stable image can be obtained. If the particle size distribution is narrowed, the image will be stable, the reproducibility of fine lines will be good, and fog will disappear.

Furthermore, it is extremely difficult for toner produced by this method to satisfy the conflicting properties of fixing properties, offset properties, blocking properties, and developability. In order to improve fixing properties and anti-offset properties, it is effective to include hydrocarbon compounds such as paraffin and polyolefin, but toner produced using this method has cationic groups concentrated on the particle surface, but the overall is a nearly homogeneous polymer, so if the molecular weight is made small and the LTg is lowered in order to improve heat fixing properties, blocking properties will deteriorate, and this will also be reflected in development, resulting in poor image quality. On the contrary,
In order to improve blocking properties, high molecular weight or cross-linked
・If you apply bridges, etc., the heat fixability will worsen, creating a vicious cycle. Therefore, a system containing one or more types of polymerizable monomers, dyes and pigments, polymers, and other additives if necessary, is suspended in a dispersion medium in which an inorganic anionic dispersant is dispersed. , in a system that polymerizes,
A method has been proposed in which the polymerizable monomer contains a cationic polymer or copolymer in its entirety.

Without being bound by any theory, in the above method, if a cationic polymerizable monomer or a poorly water-soluble organic amine compound is added to the monomer system, these substances will be deposited on the surface of the suspended particles. The monomer aggregates and is slightly distributed from the monomer system into the dispersion medium system, making the interface between the particles and the dispersion medium uncertain, and as a result, the suspended particles become a little unstable, so the particle size distribution cannot be said to be completely stable. Conceivable. If this is done by this method of incorporating the cationic polymer into the monomer system, the cationic polymer collected on the surface of the suspended particles will not be completely distributed from the monomer system into the dispersion medium system. do not have. This is because it has a high molecular weight.

Therefore, the interface of the suspended particles becomes firm and stable, making it easier for the particle sizes to become uniform. As it gathers on the surface of turbid particles, it becomes a kind of shell-like shape,
The obtained particles become pseudo capsules. That is, irrespective of the initial polymerization of the polymerizable monomer, a resin having a desired degree of polymerization can be used as the cationic polymer or copolymer for the shell. Therefore, the interior is polymerized to a relatively low molecular weight material with excellent fixing properties, and the cationic polymer or copolymer in the shell is a relatively high molecular weight material with good blocking properties and developability. , a resin with excellent wear resistance can be used.

Therefore, one or more types of polymerizable monomers,
In a system in which a system containing dyes and pigments, polymers, and other additives, if necessary, is suspended in a dispersion medium in which an anionic dispersant is dispersed and polymerized, a cationic polymer or a cationic polymer is added to the polymerizable monomer. It has been proposed to contain and polymerize a copolymer and a hydrocarbon compound. By the above method,
Although it is possible to obtain a toner that is practically satisfactory, there are, however, many requirements placed on the toner. That is, it is strongly desired to carry out fixing in a more energy-saving manner without degrading the developability, blocking, fluidity, and abrasion resistance properties. Hydrocarbon compounds are hydrophobic and have a low molecular weight, so they are difficult to mix with cationic polymers that have polar groups and large molecular weights, so they do not appear on the surface where the cationic polymer aggregates and are absorbed inside the toner. It will be pushed into the shape. During fixing, it comes out from inside, significantly improving fixing properties and offset properties. At this time, the hydrocarbon compound is considered to have a plasticity, lubricant, and oil effect.

The hydrocarbon compound used here includes paraffin, polyolefin, etc. having carbon of C0 or more, for example,
Paraffin wax (Japan Oil), paraffin wax (Japan Oil), micro wax (Japan Oil), microcrystalline wax (Japan Oil), PE-1go (
Hoechst), Mitsui Iwax 10P (Mitsui Petrochemicals), Mitsui Hiwax 220P (Mitsui Petrochemicals), Mitsui Hiwax 660P (Mitsui Petrochemicals), etc.
Particularly preferred is paraffin.

As mentioned above, the toner obtained here has excellent developability, fixing properties, anti-offset properties, and also excellent anti-blocking properties. However, although the above-mentioned toner has some hygroscopicity and there is no problem in practical use, it is desirable to further improve the developability. This hygroscopicity is due to the fact that the inorganic dispersant is hydrophilic and remains attached to the toner surface even after filtering and washing with water. In order to improve the developability of the toner, it is necessary to remove this inorganic dispersant. be.

Therefore, an object of the present invention is to provide a toner with better developability and better moisture resistance. That is, by treating the obtained polymer with an alkali after suspension polymerization, the surface of the toner is improved. The objective can be achieved by removing the attached hydrophilic inorganic dispersion.

That is, IX or more, preferably 4%, based on the weight of the polymer.
A polymer is added to the above-mentioned strong alkaline aqueous solution, and the inorganic matter on the surface of the polymer becomes an alkaline earth metal, which is separated from the polymer surface and dissolved in the alkaline aqueous solution. At this time, if the alkali used is 179 degrees or less, K ml of the inorganic dispersant will not be removed sufficiently and will remain on the toner surface.

Examples of the alkali used in the present invention include potassium hydroxide, sodium hydroxide, calcium hydroxide, tetramethylammonium hydroxide, ammonium carbonate, potassium carbonate, and sodium carbonate.

The cationic polymers used in the present invention include dimethylamine ethyl methacrylate, dimethylaminoethyl acrylate, diethylaminoethyl methacrylate, diethylaminoethyl acrylate, N-n-butoxyacrylamide trimethylammonium chloride, diaseptone acrylamide, acrylamide, and N-vinylcarbazole. , vinylpyridine, 2-vinylimidazole,
Polymers of nitrogen-containing monomers, such as 2-l nitroxy-3-methacryloxypropyltrimethylammonium chloride, 2-hydroxy-3-acryloxypropyl, or quaternized versions of nitrogen, or the following: There are copolymers of one or more of these monomers and the above nitrogen-containing monomers.

Styrene, 0-methylstyrene, m-methylstyrene,
p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3.4-dichlorostyrene, p-ethylstyrene, 2.4-dimethylstyrene% pn-phthylstyrene, P tert-butylstyrene, Styrene and derivatives thereof such as pn-hexylstyrene, pn-octylstyrene%Pn-nonylstyrene, pn-decylstyrene, and Pn-dodecylstyrene.

Vinyl monomers include, for example, ethylenically unsaturated monoolefins such as ethylene, propylene, butylene, and isobutylene; vinyl chloride, vinylidene chloride, vinyl bromide, vinyl fluoride, and vinyl halides; acetic acid; Vinyl, vinyl esters such as vinyl propionate, vinyl penzoate, vinyl butyrate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-methacrylate
-Octyl, dodecyl methacrylate, methacrylic acid-
2-ethylhexyl, stearyl methacrylate, phenyl methacrylate, dimethylamine ethyl methacrylate,
α-methylene aliphatic monocarboxylic acid esters such as diethylaminoethyl methacrylate; methyl 7-acrylate;
Ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, α- Methyl chloroacrylate; Vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, and vinyl isobutyl ether; Vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and methyl impropenyl ketone; N-vinylpyrrole, N-vinylcarbazole, N - N-vinyl compounds such as vinyl indole and N-vinylpyrrolidone; vinylnaphthalenes; acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylaterile, and acrylamide.

Examples of the polymerizable monomers used in the present invention include the following, and one or more of these may be used. Further, one or more of these polymers may be contained in the polymerizable monomer.

Styrene, 0-methylstyrene, m-methylstyrene,
p-Methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-ethylstyrene, 2,4-dimethylstyrene sT' n-butylstyrene, p-tert- Butylstyrene, p-n-hexylstyrene sp n
-Octylstyrene sP n-nonylstyrene, p-
Styrene and derivatives thereof such as n-7'' silstyrene and Pn-dodecylstyrene.

Examples of vinyl monomers include ethylenically unsaturated monoolefins such as ethylene, propylene, butylene, and imbutylene; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide, and vinyl fluoride; vinyl acetate;
Vinyl propionate, vinyl benzoate, vinyl esters such as tj2[vinyl, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-methacrylate
-octyl, dodecyl methacrylate, methacrylic acid-2
- α-methylene aliphatic monocarboxylic acid esters such as ethylhexyl, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylamine ethyl methacrylate; methyl acrylate, ethyl acrylate, n-butyl acrylate, acrylic acid Isobutyl, propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl α-chloroacrylate; vinyl methyl ether, vinyl ethyl ether , vinyl ethers such as vinyl isophthyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, methyl isopropenyl ketone; N-vinylvirol, N-vinylcarbazole, N-vinylindole,
Examples include N-vinyl compounds such as N-vinylpyrrolidone; vinylnaphthalenes; acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, and acrylamide.

As the polymerization initiator used in the present invention, oxycarbonate, cumene hydroperoxide, 2,4-dichlorylbenzoyl peroxide, lauroyl peroxide, etc. can be used.

In the present invention, a crosslinking agent may be used to form a crosslinked polymer. For example, divinylbenzene, divinylnaphthalene and derivatives thereof; diethylene carboxylic acid esters such as diethylene glycol methacrylate, triethylene glycol methacrylate, ethylene glycol dimethacrylate, and tetraethylene glycol dimethacrylate; l,2-propylene gelicol; 1 r
A general crosslinking agent such as 3-butanediol can be used as appropriate. As a dispersant that can be used in the present invention, a known anionic dispersant can be used. For example, finely powdered inorganic compounds such as colloidal silica, such as Aerosil 200 or 300, can be used.

As dyes and pigments used in the present invention, commonly known dyes and pigments can be used. Furthermore, carbon black and magnetic materials can also be used. In particular, it is best to use surface-treated magnetic materials.
A monomer system in which dyes, pigments, crosslinking agents, etc. are uniformly dissolved or dispersed is dispersed in a dispersed phase, that is, a continuous phase, containing a suspension stabilizer using a conventional stirrer, homomixer, homogenizer, etc. Preferably, the stirring speed and time are adjusted so that the monomer droplets have the desired toner particle size, generally 30 μm or less, and thereafter this state is maintained approximately by the action of the dispersion stabilizer. Stirring may be carried out to the extent that sedimentation of particles is prevented.

Polymerization is carried out by setting the polymerization temperature appropriately. After the reaction is completed, the generated toner particles are poured into an alkaline aqueous solution of a predetermined concentration or a predetermined weight of alkali IJe is introduced into a reaction tank,
The mixture is stirred at room temperature to 40° C. for 3 to 24 hours, filtered, thoroughly washed with water, and dried to obtain a toner.

All known methods can be used to develop this toner. For example, two-component development methods such as cascade method, magnetic brush method, and microtoning method; one-component development methods containing magnetic materials such as conductive-component development method, insulating-component development method, and jumping development method; powder Examples include cloud method and fur brush method; non-magnetic component development method in which toner is held on a toner carrier by electrostatic force and transported to a developing section for development.

[Example 1] Styrene monomer 200g Styrene-dimethylaminoethyl methacrylate copolymer 1o
g (mo/-v-ratio 8:2.M==50,000) Paraffin wax 130°F (manufactured by Hiki Seiro Co., Ltd.) 8 g Azobisisobutyronitrile 10 g Phthalocyanine blue 10 g
e Heat to 70″C and dissolve the copolymer, paraffin wax, initiator, etc. in the styrene monomer.
The mixture was mixed for about 5 minutes while heating to about 60° C. in a container equipped with a high shear mixing device such as a K homomixer (manufactured by Tokushu Kika Kogyo).

Separately 7 x o seal #200 in 1000cc of water 4
The mixture was dispersed in g and heated to about 60°C, and the above monomer system was added to the mixture under stirring using a TK homomixer, and the mixture was stirred at 4000 rpm for about 1 hour. Thereafter, this mixed system was stirred with paddle blade stirring to coagulate polymerization. 15 g'ii of sodium hydroxide was added to this suspension, and after stirring at room temperature for 10 hours,
A toner was obtained by filtration, washing with water, and drying.

The obtained toner has a number distribution of 9.1 μm in number average diameter and 6
．． 18% was 35μm or less, and 1% was 20.2μm or more in volume distribution. (Coulter counter, aperture 100μ) (Rating: ○, ○Δ, Δ, △×, ×), practical level 06 or higher) Image production was performed by mixing iron powder carrier EF V 250/400 (Japan Iron Powder) and toner to a toner concentration of 10 wt%, using it as a developer, and performing reverse development using a copying machine NP5500. Ta. Further, the fixing property test was conducted using a PC-10 fixing device to which no release agent such as silicone oil was applied. Fluidity was determined by visual inspection in an actual developing device. Further, when the toner was prepared without being treated with sodium hydroxide, the initial image quality was high in image density, but fog was noticeable, and with continuous durability, the fog worsened, which was not preferable.

[Example 2] Styrene monomer 180g Butyl acrylate monomer 20g Styrene-diethylaminoethyl methacrylate copolymer
log (monomer ratio 9:1, Mw=100.000
) Paraffin wax 150°F (Japanese wax) 8g Azobisisobutyronitrile 10g
BL-250 (manufactured by Titanium Industries) 6
0g ASA-30 (manufactured by Mitsubishi Kasei)
1 g of the above material was prepared in the same manner as in Example 1 to obtain a toner. The obtained toner has a number average diameter of 8.7 μm, 20% of the particles are 6.35 μm or less in number distribution, and 20.2 in volume distribution.
゛μm or more was 0%.

(Coulter counter, aperture 100μ) (Evaluation is the same as in Example 1) Images were printed using a PC-10 copying machine, and the fixing device of the same machine was used for fixing performance. Furthermore, the initial image density of the toner that had undergone the alkalization process was low, and the density decreased slightly when continuous copies were made.

[Example 3] Styrene monomer 200g Copolymer of styrene and 5% quaternization product of dimethylamine ethyl methacrylate with benzyl chloride 10
g (monomer ratio 9:1, MW gqooo) azobisisobutyronitrile IOg paraffin wax 155°F (Nippon Seiro) 10
1g of divinylbenzene 10g of phthalocyanine green were prepared in the same manner as in Example 1 to obtain a toner.

(The evaluation was the same as in Example 1) Image formation was achieved by using a magnetic attacher in the toner without mixing the carrier particles, which are held on the toner carrier by electrostatic force and transported to the developing section for development. I used it. Furthermore, the toner that was not treated with alkali had similar image quality to that of Example 2.

[Example 4] Styrene monomer 100g Styrene-dimethylaminoethyl methacrylate copolymer lo
g' (monomer ratio 9:1, Mw=150.000)
Paraffin wax 155°F (Japanese wax) 1
00gV-65 (Wako Tsumugi Pharmaceutical Industry) 1
0g Phthalocyanine Blue 10g Divinylbenzene 1g A toner was prepared in the same manner as in Example 1.

Here, the developing method is the same as in Example 3. Fixing properties were tested using a pressure fixing device using a rigid roller. Furthermore, toners in which the dispersant on the surface of the toner was not removed by alkali treatment did not have sufficient image density and were not preferred.

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Claims (1)

[Claims] It is characterized by suspending and polymerizing a monomer system containing a polymerizable monomer, a cationic polymer, and a hydrocarbon compound in a dispersion medium containing an inorganic anionic dispersant, and then treating the polymer with an alkali. Toner manufacturing method.