JPH0547113B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for producing a dry toner for developing electrostatic images in electrophotography, electrostatic recording, and electrostatic printing. A developing method using a dry toner whose main components are a colorant and a resin is as follows: (i) The dry toner is mixed with a carrier whose particle size is larger than the toner, and the toner is charged by friction with a polarity opposite to that of the electrostatic latent image. A two-component developer that develops an electrostatic latent image by applying an electric charge and bringing a developer, which is a mixture of toner and carrier, into contact with the electrostatic latent image. There is a one-component developer that allows the image to be developed. [Prior art and problems] Conventionally, in order to obtain these toners, a thermoplastic resin is melted, and a coloring agent such as a dye or a pigment, if necessary, a magnetic material, a triboelectric charge control agent, an offset preventive agent, and a lubricant are added to the melted thermoplastic resin. The method used was to add agents, mix thoroughly, cool to solidify, pulverize, and then classify to obtain the required particle size. However, the methods described above have various drawbacks. First, equipment for many processes is required, such as polymerization equipment for resin production, equipment for kneading, crushers, classifiers, etc., and the number of steps is large and energy consumption is high, which increases costs. It is the cause. The second reason is that it is difficult to obtain a uniform mixture in the kneading process, and the conditions for uniform dispersion are particularly delicate. Thirdly, in the grinding process, it is not possible to obtain only the appropriate fine powder particle size range to obtain clear, fog-free images; fine powder and coarse powder are by-produced and must be classified and removed. There are drawbacks that lead to increased costs, such as the complexity of the process, such as the difficulty in obtaining a desired particle size range, and the poor yield of obtaining a desired particle size range. Fourth, the resulting powder has an irregular shape due to pulverization, and the fluidity of the fine powder is poor.
One of the causes of image fogging is fine powder generated during both pulverization by stirring when performing frictional charging. In contrast, Special Publication No. 10231, Special Publication No. 10231, Special Publication No. 10231, Special Publication No. 10231, Special Publication No.
Publications such as No. 518305 and Japanese Patent Publication No. 51-14895 describe a method for producing toner by suspension polymerization. This suspension polymerization method does not require pulverization, the manufacturing process is simplified, and it can be said that the above-mentioned drawbacks have been improved. However, there are problems associated with suspension polymerization. In other words, dry toner is mainly made of thermoplastic resin, but it is mixed with other materials to impart and improve various functions, such as coloring agents such as dyes and pigments,
There are charge control agents that improve triboelectric charging properties, magnetic materials that provide adhesion to the developing roller, offset prevention agents that prevent toner from adhering to the fixing roller, and toner fluidity improvers. If these materials dissolve uniformly in the polymerizable monomer and do not inhibit the polymerization reaction, there is no particular problem. It is difficult to make these materials exist in a uniform state in polymer particles because of their lack of affinity for polymeric monomers. Since the added materials are non-uniformly present in the toner, the toner cannot fully perform its functions, such as not being sufficiently charged. In particular, to control the triboelectric properties of toner,
The azo metal complex dye added to the toner resin as a negative charge control agent has strong polarity. Therefore, styrenic monomers commonly used in toners,
It is difficult to dissolve in methacrylic acid ester monomers and acrylic acid ester monomers, and even if dispersed in the monomer using a dispersion means such as a ball mill, it will aggregate during polymerization, and polymerization will not occur without further agglomeration. However, since the charge control agent made of the azo metal complex dye has strong polarity, it tends to be localized on the surface of the toner particles, and there are even cases where it migrates into the aqueous phase. If the charge control agent cannot be uniformly dispersed in this way, it will not be possible to impart sufficient charging characteristics to the toner, and as a result, the charge amount will vary between toner particles, resulting in a wide charge amount distribution or vice versa. Charged toner particles are generated, causing BG fog and other negative effects on images, making it impossible to obtain good image quality. In addition, as mentioned above, the charge control agent gathers on the surface of each toner particle, so the charge control agent tends to peel off from the surface due to rubbing with the carrier or the toner particles themselves during printing, and the peeled charge The control agent adheres to the carrier surface and becomes a so-called spent toner, inhibiting efficient triboelectrification. Therefore, the image quality is further degraded. In addition, if there is a large amount of charge control agent on the particle surface, charge leakage is likely to occur, resulting in poor environmental characteristics.
If the charge control agent is insufficiently dispersed in the monomer, there are many problems associated with this. Therefore, in order to improve the performance of toner, it is important to finely and uniformly disperse the charge control agent in the monomer. SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing toner that improves the above-mentioned drawbacks. That is, the present invention relates to a method for producing a toner that has a sufficient dispersion state of a charge control agent and can provide excellent image quality, and an object of the present invention is to provide a method for producing a toner that improves the drawbacks associated with suspension polymerization. be. [Means for Solving the Problems] As a result of extensive research in order to achieve the above-mentioned object, the present inventors have discovered a method for dispersing a charge control agent made of an azo metal complex dye in a monomer. The present inventors have discovered that the dispersibility of a charge control agent can be significantly improved by carrying out dispersion in the presence of a higher fatty acid salt of a long-chain alkyl or hydroxy long-chain alkylamine having a specific structure, leading to the present invention. That is, in the present invention, a charge control agent consisting of an azo metal complex dye and a coloring agent such as carbon black are added to a polymerizable monomer by adding a long-chain alkyl or hydroxy long-chain alkylamine represented by the following general formula (1). The present invention relates to a method for producing a toner for developing electrostatic images, which comprises dispersing in the presence of a higher fatty acid salt and then carrying out suspension polymerization. (In the formula, R ₁ , R ₂ , R ₃ , R ₄ are long chain alkyl or alkenyl groups with 8 to 20 carbon atoms, long chain hydroxyalkyl or hydroxyalkenyl groups with 8 to 20 carbon atoms, and long chain hydroxyalkyl or hydroxyalkenyl groups with 1 to 2 carbon atoms. Lower alkyl group, 1 or more carbon atoms
2 hydroxyalkyl groups or benzyl groups, one or two of which are the above-mentioned long-chain alkyl or alkenyl groups or long-chain hydroxyalkyl or hydroxyalkenyl groups. _R5 has 8 or more carbon atoms
18 alkyl or alkenyl groups. ) According to the method of the present invention, a charge control agent made of an azo metal complex dye can be easily finely and uniformly dispersed in a monomer, and the dispersion is stable even during suspension polymerization, and there is no possibility of reaggregation or charging. The toner can be synthesized without the control agent being localized on the toner surface. The resulting toner therefore has excellent image quality,
It can exhibit excellent printing durability. In general formula (1), specific examples of alkyl groups, hydroxyalkyl groups, and alkenyl groups having 8 to 20 carbon atoms include C ₁₀ H ₂₁ −, C ₁₂ H ₂₅ −, C ₁₄ H ₂₉ −, C ₁₆ H ₃₃ −、
Alkyl groups such as C ₁₈ H ₃₇ −, alkenyl groups such as C ₁₆ H ₃₁ −, C ₁₈ H ₃₅ −,

【formula】

【formula】

Examples include hydroxyalkyl groups such as [Formula], and mixtures thereof may also be used. Further, higher fatty acid salts of long-chain alkyl (alkenyl) or hydroxy long-chain alkyl (alkenyl) amines represented by general formula (1) are (In the formula, R ₁ , R ₂ , R ₃ , and R ₄ are as defined above. X ₁ represents a halogen atom.) The quaternary ammonium salt represented by A higher fatty acid salt represented by the general formula (3) is added, and R ₅ −COOX ₂ (3) (wherein, X ₂ represents a hydrogen atom or an alkali metal atom, and R ₅ is as defined above)
Obtained as a precipitate during heating and stirring. The precipitate is separated, washed with water, and dried to obtain a long-chain alkyl or hydroxyalkylamine quaternary ammonium fatty acid salt. Suitable higher fatty acids or higher fatty acid salts represented by general formula (3) include, for example, C ₁₁ H ₂₃ COOH, C ₉ H ₁₉ COONa,
C ₁₅ H ₃₁ COOK, C ₁₅ H ₃₁ COOH, C ₁₃ H ₂₇ COONa,
Examples include C ₁₇ H ₃₅ COOH and C ₁₇ H ₃₅ COONa. As the higher fatty acid salt of a long-chain alkyl or hydroxy long-chain alkylamine represented by the general formula (1) used in the present invention, the following are preferred, for example. By putting the charge control agent into the monomer, adding the quaternary ammonium fatty acid salt, and then stirring, the charge control agent can be easily dispersed in the monomer. The azo metal complex dye which is a negative charge control agent used in the present invention is represented by the following general formula (4). Here, M represents a chromium or cobalt atom. Furthermore, the moieties represented by Y and Z are units containing the following aromatic rings. That is, Y,
Z is

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】 〔Effect of the invention〕

As explained above in detail, the toner for developing electrostatic images obtained by the production method of the present invention contains a negative charge control agent consisting of an azo metal complex dye in the monomer, a colorant and a specific dispersion. Since it is mixed and dispersed with a stabilizer and then subjected to suspension polymerization to form granulated polymer particles, it is possible to obtain a toner with even better dispersibility of the charge control agent than toner produced by conventional manufacturing methods. It was possible to provide a toner and a method for producing the same that not only improved the occurrence of fog during copying, but also improved developability, transferability, and printing durability. [Example] Examples of the present invention are shown below, but the present invention is not limited thereto. Note that "parts" in the examples are "parts by weight." Example 1 85 parts of styrene, 15 parts of n-butyl acrylate,
Eisenspiron Black as a charge control agent
A mixture of 2 parts of TRH (manufactured by Hodogaya Chemical Co., Ltd.) and 1 part of a higher fatty acid salt of a long-chain alkylamine represented by the following formula was stirred and dispersed. When the mixture after stirring was observed under an optical microscope, the charge control agent in the monomer was extremely fine, no development such as aggregation was observed, and the dispersibility was good. Add carbon black (manufactured by Mitsubishi Kasei Corporation) to this mixture.
#44) and 2 parts of low molecular weight polyethylene (Mitsui Hiwax 210P, manufactured by Mitsui Petrochemical Industries, Ltd.) were added, and the mixture was dispersed in a ball mill for 10 hours. After dissolving 1 part of 2,2'-azobisisobutyronitrile in this dispersion, polyvinyl alcohol (manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd., Gohsenol GL-05) was added.
The mixture was added to 250 parts of a 1% aqueous solution of and stirred for 3 minutes at 6000 rpm using a TK homo mixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). This suspension was subjected to a polymerization reaction in a separable flask at 75° C. for 8 hours under a nitrogen atmosphere at a stirring speed of 100 rpm using a conventional stirrer. After the polymerization was completed, centrifugation and water washing were repeated, followed by drying under reduced pressure to obtain a spherical toner having an average particle size of 10 μm. Carrier iron powder ((DM)
95 parts of Stuart CB-100) were mixed to prepare a developer. When this developer was used to create an image using Ricoh FT4030, a clear black image with no fog was obtained. Furthermore, when a printing durability test was performed up to 50,000 copies, there was almost no change in image quality, and the images were as clear as the initial image. Comparative Example 1 85 parts of styrene, 15 parts of n-butyl acrylate,
Eisenspiron Black as a charge control agent
When a mixture of 2 parts of TRH was stirred and observed under an optical microscope, it was clear that particles of the charge control agent with a diameter of 2 to 3 μm aggregated and were not well dispersed in the monomer. When this mixture was dispersed in a ball mill for 10 hours and observed under an optical microscope, the particle size of the charge control agent was reduced to around 1μ, but
It was still agglomerated and not well dispersed in the monomer. To this dispersion, 6 parts of carbon black (manufactured by Mitsubishi Kasei Corporation, #44) and low molecular weight polyethylene (manufactured by Mitsui Petrochemical Industries, Ltd., Mitsui Hiwax) were added.
210P) was added, and a toner was produced in the same manner as in Example 1. After suspension polymerization, the aqueous phase part took on a purple color, and some of the charge control agent had migrated to the aqueous phase. 95 parts of carrier iron powder (CB-100 manufactured by DM Stuart) was mixed with 5 parts of the obtained toner to prepare a developer. Ricoh uses this developer.
When I took an image using the FT4030, there was a lot of fog, the image was a little blurry, and there was some unevenness in the image. When this developer was tested for printing up to 3,000 sheets, the image quality further deteriorated and the image density also decreased. When the developer was separated into toner and carrier after printing, and the carrier was washed with ethyl alcohol, a purple charge control agent was eluted, and during printing, the charge control agent migrated from the toner surface to the carrier surface. That was clear. Example 2 A toner was produced under exactly the same conditions as in Example 1, except that a higher fatty acid salt of a hydroxy long-chain alkylamine represented by the following formula was used instead of the higher fatty acid salt of a long-chain alkylamine used in Example 1. was manufactured. When an image was produced using this toner in the same manner as in Example 1, a clear image with sufficient image density and no fogging was obtained. Example 3 80 parts of styrene, 10 parts of n-butyl methacrylate
10 parts of 2-ethylhexyl acrylate, 5 parts of carbon black (manufactured by Mitsubishi Kasei Corporation, #30), 2 parts of Eisenspiron Black BH (manufactured by Hodogaya Chemical Co., Ltd.),
0.5 part of higher fatty acid salt of long-chain alkylamine represented by the following formula Low molecular weight polyethylene (Mitsui Petrochemical Industries, Ltd.)
1.5 parts of the mixture was dispersed in a ball mill for 10 hours. Add 2 to this dispersion,
After dissolving 2 parts of 2'-azobis(2,4-dimethylvaleronitrile), polyvinyl alcohol (Gohsenol GM-14, manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd.) was added.
The mixture was added to 200 parts of a 1.5% aqueous solution of and stirred for 3 minutes at 7000 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). After that, the average grain size was obtained in the same manner as in Example 1.
A spherical toner having a diameter of 10 μm was produced, and an image was produced using this in the same manner as in Example 1. A clear image with sufficient image density and no fogging was obtained.

Claims (1)

[Claims] 1. A polymerizable monomer, a charge control agent comprising an azo metal complex dye, and a coloring agent according to the following general formula: (In the formula, R ₁ , R ₂ , R ₃ , R ₄ are long chain alkyl or alkenyl groups with 8 to 20 carbon atoms, long chain hydroxyalkyl or hydroxyalkenyl groups with 8 to 20 carbon atoms, and long chain hydroxyalkyl or hydroxyalkenyl groups with 1 to 2 carbon atoms. Lower alkyl group, 1 or more carbon atoms
2 hydroxyalkyl groups or benzyl groups, one or two of which are the above-mentioned long-chain alkyl or alkenyl groups or long-chain hydroxyalkyl or hydroxyalkenyl groups. _R5 has 8 or more carbon atoms
18 alkyl or alkenyl groups. 1. A method for producing a toner for developing an electrostatic image, which comprises dispersing in the presence of a higher fatty acid salt of a long-chain alkyl or hydroxy long-chain alkylamine represented by the following formula, and then carrying out suspension polymerization.