JPH0153786B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a toner for developing electrostatic images, and more specifically, 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 electrostatic images, and more specifically, a method for producing a toner for developing an electrostatic image. The present invention relates to a method for producing a toner for developing an electrostatic image, which comprises suspending the toner in a toner 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 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 economical, 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. In particular, during 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, release agents such as silicone oil are applied to the fusing roller. Painting has 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 were made to add a larger amount of polyolefin or to use polyolefin with a lower melting point, but these efforts resulted in fusion in the crusher or classifier, or polyolefin with a lower melting point appeared on the surface of the toner. This results in blocking and poor fluidity, which significantly reduces developability. In order to overcome the drawbacks of the pulverization method, a method for producing toner using a suspension polymerization method was proposed. In other words, since this method does not involve any pulverization process, brittleness is not required, and since the material is spherical in shape, it has excellent fluidity, and as a result, triboelectric charging is uniform. 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. Suspension stability is generally achieved by using 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 anionically charged by the anionic polymerizable monomer, while the inorganic dispersant The inorganic dispersant completely and uniformly coats the surface of the polymerizable monomer particles with strong ionic bonds to prevent coalescence, resulting in a number average diameter of about 10 to 20μ. A method for obtaining fine particles 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. 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 very 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 anionic groups gathered on the particle surface, but since the entire polymer is almost homogeneous, it is necessary to reduce the molecular weight and lower the Tg (glass transition point) in order to improve heat fixability. Blocking properties deteriorate, and this is also reflected in development, resulting in poor image quality. On the other hand, if polymerization or crosslinking is performed in order 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 a cationic dispersant is dispersed. A method has been proposed in which the polymerizable monomer contains an anionic polymer or copolymer in the polymerization system. Without being bound by theory, when an anionic 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 form a 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. When this is done by incorporating the anionic polymer into the monomer system, the anionic polymer collected on the surface of the suspended particles is distributed from the monomer system into the dispersion medium system. Never. 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 sizes to be uniform. In particular, anionic styrenic copolymers
As they gather on the surface of suspended particles, they take on a kind of shell-like form, and the resulting 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 anionic styrenic copolymer for the shell. Therefore, the interior is polymerized to have a relatively low molecular weight with excellent fixing properties, and the anionic styrene 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 satisfies the needs of practical use; however, there are many additional requirements placed on the toner. That is,
It is strongly desired to perform fixing in a more energy-efficient 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. Specifically, in the present invention, an anionic styrenic copolymer is dissolved in a monomer system containing styrene or a styrene derivative as a polymerizable monomer and a hydrocarbon compound, and mixed while heating. Then, the heated monomer system in which the anionic styrenic copolymer is dissolved is suspended in a heated dispersion medium containing cationic colloidal silica treated with a nitrogen-containing silanizing agent, and polymerization is carried out. The present invention relates to a method for producing a toner for developing an electrostatic image, characterized in that the toner is produced by Without being bound by theory, hydrocarbon compounds are hydrophobic and have a low molecular weight, so they are difficult to mix with styrene copolymers, which have polar groups and have a large molecular weight. It is pushed into the inside of the toner without coming out. Then, it comes out from the inside during fixing, improving fixing properties.
Significantly improves offset properties. 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 Co., Ltd.), paraffin wax (Memoto Seiyaku), microwax (Nippon Oil Co., Ltd.), and microwax (Nippon Oil Co., Ltd.). ), Microcrystalline Wax (Nippon Seiro), PE-130 (Hoechst), Mitsui Hiwax 110P (Mitsui Petrochemical), Mitsui Hiwax 220P (Mitsui Petrochemical), Mitsui Hiwax 660P (Mitsui Petrochemical), etc. Paraffin is preferred. Examples of the anionic styrenic copolymer used in the present invention include 2-acrylamide-2-methylpropanesulfonic acid, N-methylolacrylamide, methacrylic acid, acrylic acid, and methacrylic acid-
Hydroxyl groups, carboxyl groups such as 2-hydroxyethyl, 2-hydroxypropyl methacrylate, glycidyl methacrylate, polypropylene glycol monomethacrylate, polyethylene glycol monomethacrylate, tetrahydrofurfuryl methacrylate, acid phosphooxyethyl methacrylate, maleic anhydride, Anionic polymerizable vinyl monomer containing sulfonic acid group, phosphoric acid group, acid anhydride group, styrene, O-methylstyrene, P
-Methylstyrene, 2,4-dimethylstyrene,
Copolymers with styrene such as styrene or styrene derivatives such as Pn.butylstyrene, P-tert-butylstyrene, Pn.dodecylstyrene, P-chlorostyrene, and P-phenylstyrene can be mentioned. Preferably, the anionic styrenic copolymer has a weight average molecular weight of 50,000 to 150,000, as shown in the examples below. Furthermore, vinyl monomers that may be copolymerized with the anionic styrenic copolymer according to the present invention include vinylnaphthalenes, ethylene,
Ethylenically unsaturated monoolefins such as propylene and isobutylene; vinyl esters such as vinyl chloride, vinyl acetate, vinyl butyrate, vinyl benzoate; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, acrylic acid Propyl, n-octyl acrylate, 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, n-octyl methacrylate, dotesyl methacrylate, methacrylate α-methylene aliphatic monocarboxylic acid esters such as lauryl acid, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, and diethylaminoethyl methacrylate; acrylics such as acrylonitrile, methacrylonitrile, and acrylamide; Acid or methacrylic acid derivative; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, methyl isoprovinyl ketone; N-vinylpyrrole,
Examples include N-vinyl compounds such as N-vinylcarbazole, N-vinylindole, 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
-Styrenes such as styrene such as phenylstyrene or styrene derivatives. moreover,
As polymerizable monomers that may be used in some cases,
Ethylenically unsaturated monoolefins such as vinylnaphthalenes, ethylene, propylene, and isobutylene; vinyl esters such as vinyl chloride, vinyl acetate, vinyl butyrate, and 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, acrylic acid 2
- Chlorethyl, phenyl acrylate, methyl α-chloroacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, 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 derivatives such as acrylonitrile, methacrylonitrile, and acrylamide; 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 isoprovinyl ketone; N Examples include N-vinyl compounds such as -vinylpyrrole, N-vinylcarbazole, N-vinylindole, and N-vinylpyrrolidene. 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. In the present invention, a crosslinked polymer may be formed using a crosslinking agent. For example, divinylbenzene, divinylnaphthalene and their derivatives, diethylene glycol methacrylate, triethylene glycol methacrylate, ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, etc., 1,2-propylene glycol, 1,3- Common crosslinking agents such as butanediol can be used as appropriate. Examples of the cationic dispersant include hydrophilic positively charged colloidal silica treated with a silane treatment agent containing nitrogen such as an amino group. 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 suspending a monomer system in which a polymerization initiator, monomers such as anionic styrenic copolymers, styrene or styrene derivatives, additives, dyes and pigments, crosslinking agents, etc. are uniformly dissolved or dispersed. It is dispersed in a dispersed phase, ie, a continuous phase, containing cationic colloidal silica as a 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 produced toner particles are recovered and dried by a suitable method such as processing, washing, filtration, 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, and 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-maleic anhydride copolymer (monomer ratio 9:1, w=50000) 10g Parafine Wax 130 (manufactured by Nippon Seiro Co., Ltd.)
8g azobisisobutyronitrile 10g phthalocyanine blue 10g are heated to 70°C, and the copolymer, paraffin wax, initiator, etc. are dissolved in the styrene monomer.
This was heated to about 60°C in a melter equipped with a high shear mixing device such as TK Homomixer (manufactured by Tokushu Kika Kogyo).
The mixture was mixed for about 5 minutes while heating to . Separately add H ₂ N―CONH―CH ₂ CH ₂ CH ₂ to water 1000c.c.
4g of hydrophilic positively charged silica treated with -Si-(OC ₂ H ₅ ) ₃ was dispersed, heated to approximately 60°C, and the above monomers were added to the TK homomixer while stirring. Add the above monomer while stirring,
The mixture was stirred 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 9.4 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). This was prepared using the same method as Comparative Example 1 with a different composition.
- compared with 3. The other compositions of the comparative example are the same as those of the example.

【table】

[Table] *Evaluation is in 5 stages: ○, ○△, △, △×, % to form a developer, which was developed using a copying machine NP 5500. In addition, 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. Regarding abrasion resistance, the carrier after continuous image durability is separated from the toner, and the amount of toner stuck to the carrier, which is commonly referred to as spent toner, is examined and evaluated on a 5-point scale from almost none (○) to very much (×). separated. This roughly corresponded to the image quality of continuous image durability. Example 2 Styrene monomer 180g Butyl acrylate monomer 20g Styrene-methacrylic acid copolymer (monomer ratio 9:1, w=100000) 10g Paraffin wax (Nippon Seiro) 8g Azobisisobutyronitrile 10g BL-250 (Titanium) (manufactured by Kogyo) 60g ASA-30 (manufactured by Mitsubishi Kasei) 1g The above materials were prepared in the same manner as in Example 1 to obtain a toner. The obtained toner had a number average diameter of 8.7 μm, and 0% of the number distribution was 20.2 μm. (Coulter counter, aperture 100μ). As a comparative example, the following toner was prepared and compared in the same manner as in Example 1.

【table】

[Table] *Evaluation is in 5 stages: ○, ○△, △, △×, ×. Practical level is ○△ or above. Image output is performed using an NP-400RE copying machine.
The same machine's fixing device was used for fixing performance. Abrasion resistance was determined by wiping off dirt on the sleeve after toner was removed using MEL, and visually evaluating the degree of dirt on a five-point scale. Example 3 Styrene monomer 200g Styrene and 2-hydroxyethyl methacrylate copolymer (monomer ratio 9:1, w=
50000) 10g azobisisobutyronitrile 10g Paraffin Wax 155 (Nippon Seiro) 10g 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] *Evaluation is in 5 stages: ○, ○△, △, △×, ×. Practical level is ○△ or above Image output is maintained by electrostatic force on the toner carrier. Therefore, a method was used in which a toner containing no magnetic material was used without mixing carrier particles, which was transported to a developing section and developed. The fixing properties were tested using the heat roller fixing device of a PC-10 copier. Abrasion resistance was tested in the same manner as in Example 2. Example 4 Styrene monomer 100g Styrene-maleic anhydride copolymer (monomer ratio 9:1, w=150000) 10g Parafine wax 155 (Nippon Seiro) 100g V-65 (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 Examples 1 to 3.

【table】

[Table] *Evaluation was in five stages: ○, ○△, △, △×, ×, and the practical level was ○△ or above. The developing method here was the same as in Example 3. Fixing properties were tested using a pressure fixing device using a steel roller. Abrasion resistance is the same as in Example 3.

Claims (1)

[Scope of Claims] 1 An anionic styrenic copolymer is dissolved in a monomer system containing styrene or a styrene derivative as a polymerizable monomer and a hydrocarbon compound, and mixed while heating, A heated monomer system in which an anionic styrenic copolymer is dissolved is suspended in a heated dispersion medium containing cationic colloidal silica treated with a nitrogen-containing silanizing agent and polymerized. A method for producing a toner for developing an electrostatic image, the method comprising: producing a toner. 2. The method for producing a toner according to claim 1, wherein the anionic 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 monomer system contains a crosslinking agent. 4. Claims 1 to 3, wherein the anionic styrenic copolymer is a copolymer of styrene and an anionic vinyl monomer having a hydroxyl group, a carboxyl group, or an acid anhydride group. toner manufacturing method.