JPH0153785B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a toner for developing an electrostatic image, and more particularly, the present invention relates to a method for producing a toner for developing electrostatic images, and more particularly, the present invention relates to a method for producing a toner for developing an electrostatic image. This invention relates to a method for producing a toner for developing electrostatic images, which is obtained by suspending and polymerizing the toner. Conventional toners generally contain colorants and thermoplastic resins.
After melt-mixing and uniformly dispersing other additives,
Toner having a desired particle size has been manufactured using a pulverizer and a classifier. Although this manufacturing method can produce fairly good toners, it does have certain limitations. In other words, the toner obtained using the pulverization method is
The material must have some brittleness to make it susceptible to crushing. However, if the toner is too brittle, it will be too finely pulverized, and later, in order to obtain a toner with an appropriate particle size distribution, it will be necessary to cut the toner into a finer powder, 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 or a material with pressure fixing properties 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 that it has triboelectric properties suitable for development, that it forms an excellent image;
The characteristics include no change in performance when left standing, no solidification (blocking, etc.), appropriate heat or pressure fixing properties, and no contamination of the surface of the photoreceptor. Particularly in fusing, the offset phenomenon in which toner adheres to the fusing roller and is retransferred onto the next copy paper is a constant problem. To prevent this, a release agent such as silicone oil is applied to the fusing roller. things have been done. However, in recent years, it has become common to include a polyolefin such as polypropylene or polyethylene in the toner to prevent offset without applying a release agent to the fixing roller. However, this method is not sufficiently effective in preventing offset, requires an auxiliary fixing roller cleaning device, and cannot perform mass copying without maintenance. Therefore, attempts have been made to add a larger amount of polyolefin or to use a polyolefin with a lower melting point, but this results in fusion in the crusher or classifier, or blocking due to the appearance of the polyolefin with a lower melting point on the surface of the toner. Otherwise, the fluidity deteriorates and the developability is significantly reduced. 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 this method does not involve any pulverization process, brittleness is not required, and the spherical shape provides excellent fluidity, resulting in uniform triboelectrification. However, it is technically difficult to carry out polymerization in a stable suspended system without coalescence, and to obtain fine polymer particles with a uniform particle size distribution through polymerization. Therefore, when suspension polymerizing a polymerizable monomer system in water, a suspension stabilizer is used to prevent coalescence of polymer particles as the polymerization progresses. Generally, suspension stabilizers include poorly soluble finely powdered inorganic compounds such as BaSO ₄ , CaSO ₄ , MgCO ₃ ,
Slightly soluble salts such as BaCO ₃ , CaCO ₃ , Ca ₃ (PO ₄ ) ₂ , inorganic polymers such as diatomaceous earth, talc, silicic acid, clay, metal oxide powders, water-soluble polymers such as polyvinyl alcohol, gelatin , starch, etc. Furthermore, stirring also affects the stability of polymerization and particle size. 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, the particle size that satisfies the toner, that is, the number average diameter of 10 to
It is difficult to obtain fine particles of about 20μ. This is because, in the end, there are not enough ways to prevent coalescence. Therefore, in the combination of a polymerizable monomer and an inorganic dispersant, the interface of the polymerizable monomer particles is cationically charged by adding a cationic polymerizable monomer or a poorly water-soluble organic amine compound, while the inorganic dispersant The dispersant is charged with an anion opposite to that of the polymerizable monomer particles, so the inorganic dispersant completely and uniformly covers the surface of the polymerizable monomer particles with strong ionic bonds, preventing coalescence and reducing the number of particles. Average diameter is 10~
A method of obtaining fine particles of about 20μ 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 for the toner particle size distribution to be narrower. In other words, as the particle size becomes uniform, the amount of charge on each particle becomes almost the same,
Therefore, stable images can be obtained. The narrower the particle size distribution, the more stable the image, the better the reproducibility of fine lines, and the less fog there will be. Furthermore, it is difficult for toner produced by this method to satisfy contradictory properties such as offset properties, fixing properties, blocking properties, and developability. The toner produced by this method has cationic groups gathered on the particle surface, but the entire polymer is almost homogeneous. Therefore, in order to improve heat fixability, the molecular weight is reduced and the Tg (glass transition point) is lowered. Blocking properties deteriorate, and this is also reflected in development, resulting in poor image quality. On the other hand, if the molecular weight is increased or crosslinked to improve blocking properties, then heat fixing properties deteriorate, resulting in 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 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 and is polymerized. Without being bound by theory, when a cationic polymerizable monomer or a poorly water-soluble organic amine compound is added to the monomer system in the above method, these substances collect on the surface of the suspended particles, and the monomer system It is thought that the particles are slightly distributed from the inside into the dispersion medium system, and the interface between the particles and the dispersion medium becomes uncertain, which makes the suspended particles a little unstable, so that the particle size distribution cannot be said to be sufficiently narrow. If this is done by incorporating the cationic polymer into the monomer system, the cationic polymer collected on the surface of the suspended particles will be completely distributed from the monomer system into the dispersion medium system. There is no. This is because it has a high molecular weight. Therefore, the interface between the suspended particles becomes firm and stable, making it easier for the particle size to be uniform. In particular, since the cationic polymer or copolymer collects on the surface of the suspended particles, they form a kind of shell-like form, and the resulting particles become pseudo-capsules. That is, irrespective of the polymerization of the initial polymer 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 have a relatively low molecular weight with excellent fixing properties, and the cationic polymer or copolymer in the shell has a relatively high molecular weight and has good blocking properties, developability, and abrasion resistance. Excellent resins can be used. By the above method, it is possible to obtain a toner that is practically satisfactory.
Furthermore, there are many demands placed on toners. 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. Therefore, an object of the present invention is to provide a novel method for producing a toner for developing an electrostatic image using such suspension polymerization. Furthermore, the present invention provides a method for producing a toner for developing electrostatic images having a very narrow particle size distribution. Furthermore, the present invention provides a method for producing a toner having good fixing properties, good offset properties, and good blocking properties. Furthermore, the present invention provides a method for producing a toner for developing electrostatic images that has good fluidity and good developability. Furthermore, the present invention provides a method for producing an electrostatic image developing toner having good abrasion resistance. That is, a system containing one or more types of polymerizable monomers, dyes and pigments, polymers, and other additives as necessary is suspended in a dispersion medium in which an anionic dispersant is dispersed, This objective can be achieved by adding a cationic styrenic copolymer or a copolymer and a hydrocarbon compound to the polymerizable monomer in the polymerization system and polymerizing the polymerizable monomer. Specifically, the present invention provides a cationic styrenic copolymer of styrene or a styrene derivative and a nitrogen-containing vinyl monomer, which contains styrene or a styrene derivative as a polymerizable monomer and contains a hydrocarbon. The heated monomer system containing the cationic styrenic copolymer is dissolved in the monomer system containing the compound and mixed with heating, and the heated monomer system containing the anionic dispersant is mixed with the heated dispersion medium containing the anionic dispersant. This invention relates to a method for producing a toner for developing an electrostatic image, characterized in that the toner is suspended in a toner and polymerized to produce a toner having a pseudo-capsule structure. Without being bound by theory, the hydrocarbon compound used in the present invention is hydrophobic and has a low molecular weight, so it is difficult to mix with the cationic styrenic copolymer, which has a polar group and has a large molecular weight. The styrene-based copolymer is not on the surface where it gathers, but is pushed into the inside of the toner. During fixing, it comes out from inside, significantly improving fixing performance and offset performance. At this time, the hydrocarbon compound is thought to function as a plasticizer, a lubricant, and an oil effect. The hydrocarbon compound used in the present invention is preferably paraffin, polyolefin, etc. having carbon of C ₆ or more, such as paraffin wax (Nippon Oil), paraffin wax (Memoto Wax), microwax (Nippon Oil). , Microcrystalline Wax (Nippon Seiro), PE-130 (Hoechst), Mitsui Hiwax 110P (Mitsui Petrochemical), Mitsui Hiwax 220P (Mitsui Petrochemical), Mitsui Hiwax
660P (Mitsui Petrochemical), and paraffin is particularly preferred. In addition, examples of the cationic styrenic copolymer used in the present invention include dimethylaminoethyl methacrylate, dimethylaminoethyl acrylate, diethylaminoethyl methacrylate, diethylaminoethyl acrylate, N-n-poxyacrylamide, Trimethylammonium chloride, diacetone acrylamide, acrylamide, N-vinylcarbazole, vinylpyridine, 2-vinylimidazole, 2-hydroxy-3-methacryloxypropyl, trimethylammonium chloride, 2-hydroxy-3-acryloxypropyl, these nitrogens Examples include cationic styrenic copolymers of nitrogen-containing vinyl monomers and styrene or styrene derivatives described below, such as quaternized ones.
Preferably, as shown in the examples below,
The cationic styrenic copolymer preferably has a weight average molecular weight of 50,000 to 150,000. For example, styrene, O-methylstyrene, P-methylstyrene, 2,4-dimethylstyrene, P-n.
Butylstyrene, P-tert-butylstyrene, P
-n-dodecylstyrene, p-chlorstyrene,
Examples include styrenes such as styrene or styrene derivatives such as P-phenylstyrene, and vinyl monomers that may be copolymerized with the cationic styrenic copolymer include vinylnaphthalenes, ethylene, propylene, and isobutylene. Ethylenically unsaturated monoolefins such as vinyl chloride, vinyl acetate, vinyl butyrate, vinyl benzoate, etc.; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, acrylic n-octyl acid, dodecyl acrylate, lauryl acrylate,
2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl α-chloroacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, methacrylate n-octyl acid,
dodecyl methacrylate, lauryl methacrylate,
α-methylene aliphatic monocarboxylic acid esters such as 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, acrylic acid or methacrylic acid such as acrylonitrile, methacrylonitrile, acrylamide, etc. Acid derivatives; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, methyl isoprobenyl ketone; N-vinylpyrrole, N-vinylcarbazole, N-vinyl Examples include N-vinyl compounds such as indole and N-vinylpyrrolidene. Examples of the polymerizable monomer used in the present invention include styrene, O-methylstyrene, P-methylstyrene, 2,4-dimethylstyrene, P-n-butylstyrene, P-tert-butylstyrene, P-
n-dodecylstyrene, P-chlorstyrene, P
-Styrene or styrene derivatives such as phenylstyrene, and optionally vinylnaphthalenes, ethylenically unsaturated monoolefins such as ethylene, propylene, and isobutylene;
Vinyl esters such as vinyl chloride, vinyl acetate, vinyl butyrate, vinyl benzoate; methyl acrylate, ethyl acrylate, n-butyl acrylate,
Isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl α-chloroacrylate, methacryl Methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, methacrylate α-methylene aliphatic monocarboxylic acid esters such as dimethylaminoethyl acid and diethylaminoethyl methacrylate; acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, and acrylamide;
vinyl methyl ether, vinyl ethyl ether,
Vinyl ethers such as vinyl isobutyl ether; Vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and methyl isoprobenyl ketone; Examples include vinyl compounds. One or more of these may be used.
Further, one or more of these polymers may be contained in the polymerizable monomer. Examples of the polymerization initiator used in the present invention include azobisisobutyronitrile (AIBM), benzoyl peroxide, methyl ethyl ketone peroxide, isopropyl peroxy carbonate,
It can be carried out using cymene hydroperoxide, 2,4-dichlorylbenzoyl peroxide, lauroyl peroxide, etc. Further, in the present invention, a crosslinking agent may be used to form a crosslinked polymer. For example, divinylbenzene,
Divinylnaphthalene and derivatives thereof, such as diethylene glycol methacrylate, triethylene glycol methacrylate, ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, etc., 1,2-propylene glycol, 1,3-butanediol, etc. in general A crosslinking agent can be used as appropriate. As the dispersant that can be used in the present invention, known anionic dispersants can be used. Examples include water-soluble polymers such as polyvinyl alcohol, partially saponified polyvinyl alcohol, and other vinyl alcohol copolymers, and finely powdered inorganic compounds such as colloidal silica, such as Aerosil #200 or #300. can. Generally known dyes and pigments can be used as appropriate in the present invention. Furthermore, carbon black and magnetic materials can also be used. In particular, magnetic materials should be surface-treated. The suspension method involves a polymerization initiator, a cationic polymer or its copolymer, monomers and additives, dyes and pigments,
A monomer system in which a crosslinking agent and the like are uniformly dissolved or dispersed is dispersed in a dispersed phase, ie, a continuous phase, containing a suspension stabilizer using a conventional stirrer, homomixer, homogenizer, or the like. 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 after that, this state is maintained approximately by the action of a 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 processed, washed, filtered,
It is collected and dried by a suitable method such as decantation, centrifugation, etc. All known methods can be used to develop this toner. For example, two-component development methods such as cascade method, magnetic brush method, microtoning method; conductive-component development method, insulating-component development method,
One-component development method containing a magnetic material such as jumping development method; Powder cloud method and fur brush method; Examples include a magnetic one-component development method. Example 1 Styrene monomer 200g Styrene-dimethylaminoethyl methacrylate copolymer 10g (monomer ratio 8:2, = 50000) Parafine wax 130 8g (manufactured by Nippon Seiro Co., Ltd.) Azobisisobutyronitrile 10g Phthalocyanine blue 10g Heat to 70°C and dissolve the copolymer, paraffin wax, initiator, etc. in the styrene monomer.
This was mixed for about 5 minutes while heating to about 60° C. in a container equipped with a high shear mixing device such as TK Homo Mixer (manufactured by Tokushu Kika Kogyo). Separately, 4 g of Aerosil #200 was dispersed in 1000 c.c. of water, heated to about 60°C, and the above monomer system was added to the mixture while stirring with a TK homomixer, followed by stirring at 4000 rpm for about 1 hour. Thereafter, this mixed system was stirred with paddle blade stirring to complete the polymerization. Thereafter, the dispersant was removed, washed with water, filtered and dried to obtain a toner having a pseudo capsule structure. The obtained toner had a number average diameter of 9.1 μm, a number distribution of 18% of particles of 6.35 μm or less, and a volume distribution of 1% of particles of 20.2 μm or more (Coulter counter, aperture 100 μm). Comparative Example 1 with the same preparation method but different composition
- compared with 3. The other compositions of the comparative example are the same as those of the example.

【table】

[Table] Images were produced by mixing iron powder carrier EFV250/400 (Japan Iron Powder) and toner to a toner concentration of 10 wt%, using the developer as a developer, and performing reversal development using a copying machine NP5500. Furthermore, the fixing property test was conducted using a PC-10 fixing device without applying a release agent such as silicone oil. Fluidity was determined by visual inspection in an actual developing device. Example 2 Styrene monomer 180g Butyl acrylate monomer 20g Styrene-diethylaminoethyl methacrylate copolymer 10g (monomer ratio 9:1, = 100000) Parafine wax 150〓 8g (manufactured by Nippon Seiro Co., Ltd.) Azobisisobutyronitrile 10g BL -250 (manufactured by Titanium Industries) 60g ASA-30 (manufactured by Mitsubishi Kasei) 1g The above materials were prepared in the same manner as in Example 1 to obtain toner. The obtained toner had a number average diameter of 8.7 μm, a number distribution of 6.35 μm or less in 20%, and a volume distribution of 20.2 μm or more in 0%. As a comparative example, the following toner was prepared and compared in the same manner as in Example 1.

【table】

[Table] Images were printed using a PC-10 copier, and the same machine's fixing device was used for fixing. Example 3 Styrene monomer 200g Copolymer of styrene and dimethylaminoethyl metal acrylate with 5% quaternary compound of benzyl chloride (monomer ratio 9:1, =
50000) 10g Azobisisobutyronitrile 10g Paraffin Wax 155〓 10g (manufactured by Nippon Seiro Co., Ltd.) Divinylbenzene 1g Phthalocyanine Green 10g were prepared in the same manner as in Example 1 to obtain a toner. A toner of a comparative example was prepared in the same manner as in Examples 1 and 2 and compared.

【table】

[Table] The toner is held on the toner carrier by electrostatic force and transported to the developing section where it is developed. This was carried out by a method in which a toner containing no magnetic material was developed without mixing carrier particles. The fixing properties were tested using the heat roller fixing device of a PC-10 copier. Example 4 Styrene monomer 100g Styrene-dimethylaminoethyl methacrylate copolymer 10g (monomer ratio 9:1, = 150000) Parafine wax 155〓 100g (manufactured by Nippon Seiro Co., Ltd.) V-65 (manufactured by Wako Pure Chemical Industries) 10g Phthalocyanine blue 10g Divinylbenzene 1g A toner was prepared in the same manner as in Example 1.
Comparative toners were prepared and compared in the same manner as in Examples 1 to 3.

【table】

[Table] The developing method here is the same as in Example 3. Fixing properties were determined using a pressure fixing device using a rigid roller.

Claims (1)

[Claims] 1. A cationic styrenic copolymer of styrene or a styrene derivative and a nitrogen-containing vinyl monomer, which contains styrene or a styrene derivative as a polymerizable monomer and contains a hydrocarbon compound. The heated monomer system containing the cationic styrenic copolymer is dissolved in the heated dispersion medium containing the anionic dispersant and mixed while heating. 1. A method for producing a toner for developing electrostatic images, which comprises suspending and polymerizing to produce a toner having a pseudo-capsule structure. 2. The method for producing a toner according to claim 1, wherein the cationic styrenic copolymer has a weight average molecular weight of 50,000 to 150,000. 3. The method for producing a toner according to claim 1 or 2, wherein the anionic dispersant is colloidal silica. 4. The method for producing a toner according to any one of claims 1 to 3, wherein the monomer system contains a crosslinking agent.