JP3088530B2 - Electrophotographic toner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel toner for developing an electrostatic image in electrophotography, electrostatic recording and the like. The present invention relates to a novel resin particle and a novel production method.

[0002]

2. Description of the Related Art In recent years, in order to improve the image quality and durability of an electrophotographic system, it has been required to reduce the toner particle size, narrow the particle size distribution, sufficient coloring power, and control the uniform charging of toner particles. ing. An electrostatic charge developing toner is usually manufactured by melt-kneading a thermoplastic resin and a colorant, pulverizing the mixture, and then classifying the mixture. If an attempt is made to obtain a toner having a small particle size and a narrow particle size distribution in this way, the production capacity and yield will be significantly reduced, and not only will the cost increase, but also the smaller the particle size, Poor toner charging characteristics due to uneven dispersion of the charge control agent during the process occur. Further, the surface shape of the particles obtained by the pulverization has considerably many projections, and fusion to the carrier or the member for thinning the toner tends to occur. Further, an expensive charge control agent or the like which originally exerts a function on the surface of the toner is also contained in the inside of the toner.

Therefore, many proposals have been made regarding a toner having high image quality and high durability and a method for producing the same.
For example, a method of forming core particles containing a color pigment and a charge control agent therein by a suspension polymerization method (Japanese Patent Publication No. 51-14895)
No. 47-51830), but it is difficult to remove the dispersion stabilizer and the like adhering to the surface, and it is easy to cause charging deterioration. It is difficult to stably produce a product having a narrow particle size distribution. In addition, the core particles containing the pigment and the charge controlling agent are formed by spray granulation (Japanese Patent Publication No. 57-494).
This method is very difficult to control the particle size and requires classification after granulation, or a resin effective for preventing hot offset from occurring. Has the disadvantage that it cannot be used.

On the other hand, as a method for obtaining a uniform particle size, a method has been proposed in which a dispersion polymer polymerized in a solvent in which a monomer is a good solvent but a polymer is a poor solvent is dyed in a dye solution. In this method, it is difficult to obtain a stable negatively charged toner because the dispersion stabilizer used during polymerization adheres to the surface and affects the charging.

[0005]

SUMMARY OF THE INVENTION The present invention provides an electrophotographic toner in which the above disadvantages are improved. A first object of the present invention is to provide a toner having high image quality and high durability by using a small particle size toner having a narrow particle size distribution.
A second object of the present invention is to provide a negatively charged toner having good environmental stability.

[0006]

According to the present invention, there is provided an electrophotographic toner comprising a thermoplastic resin and a colorant as main components, wherein the thermoplastic resin is obtained by polymerizing a fluorine-containing acrylic polymer as a dispersant. It is a polymer particle.

Further, the fluorine-containing acrylic polymer is 2,2,2-trifluoroethyl acrylate,
2,3,3-tetrafluoropropyl acrylate,
2,2,3,3,4,4,5,5-octafluoropentyl acrylate, 2,2,3,3-tetrafluoropropyl methacrylate, 2,2,3,3,4,4,5
It is a polymer or copolymer of a monomer selected from 5-octafluoropentyl methacrylate.

A step of dissolving a fluorine-containing acrylic polymer in a hydrophilic organic solvent, wherein the resulting polymer is dissolved in the hydrophilic organic solvent, and the resulting polymer is swollen by the hydrophilic organic solvent; Alternatively, the present invention relates to a method for producing an electrophotographic toner, comprising a step of adding one or more vinyl monomers that hardly dissolve and polymerizing the same, and a step of dyeing the produced polymer with a dye.

The thermoplastic resin used in the present invention is a dispersion-polymerized particle obtained by polymerizing a fluorine-containing acrylic polymer as a dispersant, and a monomer forming such a polymerized particle is, for example, styrene, parachlorostyrene, or the like. Vinyltoluene, vinyl chloride, vinyl bromide, vinyl fluoride, vinyl acetate, vinyl propionate, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate , Isobutyl (meth) acrylate, dodecyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, ( Meta)
2-chloroethyl acrylate, (meth) acrylonitrile, (meth) acrylamide, (meth) acrylic acid, vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl methyl ketone, N-vinyl pyrrolidone, N-vinyl pyridine, butadiene, etc. Or a copolymer of two or more of these monomers, or a mixture thereof.

Black pigments: carbon black (oil furnace black, channel black, lamp black, acetylene black, activated carbon, charcoal, etc.); azine-based pigments such as aniline black; metal salt azo dyes; Products, composite metal oxides, oil black, etc. Yellow pigment: yellow lead, zinc, cadmium yellow, mineral fast yellow, nickel titanium yellow, navels yellow, naphthol yellow S, Hansa yellow 10
G, benzidine yellow GR, quinoline yellow lake, permanent yellow NCG, tartrazine lake and the like. Orange pigment: red lead, molybdenum orange, permanent orange GTR, pyrazolone orange, vulcan orange, indanthrene brilliant orange RK, benzidine orange G, indanthrene brilliant orange GK and the like. Red pigment: Bengala, cadmium red, permanent red 4R, lithol red, pyrazolone red, watching red calcium salt, lake red D, brilliant carmine 6B, eosin lake, rhodamine lake B, alizarin lake, brilliant carmine 3B and the like. Purple pigment: Manganese purple, Fast Violet B, methyl violet, etc. Blue pigment: Navy blue, cobalt blue, alicari blue, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, partially chlorinated phthalocyanine blue, fast sky blue, indanthrene blue BC, malachite green lake, etc.
Species or two or more can be used.

As a method of obtaining the toner, a method of kneading and pulverizing a charge control agent, a releasing material, and the like in addition to the thermoplastic resin and the colorant is also possible, but a toner having a small particle size distribution is obtained. For this purpose, a method of dyeing the polymer particles obtained by the dispersion polymerization method with a colorant is preferable.

The method of dyeing the dispersion-polymerized particles of the present invention with a colorant includes a method of dyeing in water using a disperse dye under heating, and a method of dyeing an organic solvent using an oil-soluble dye. Although there is a method by dyeing, when dyeing the dispersion polymer particles of the present invention, solvent dyeing is preferred. As the solvent used here, general-purpose organic solvents can be used, but alcohol solvents such as methanol, ethanol, n-propyl alcohol, iso-propyl alcohol, n-butyl alcohol, iso-butyl alcohol, and t-butyl alcohol are preferable. Depending on the solubility of the resin, it is also possible to add another solvent to the alcohol solvent and dye with a mixed solvent, or dye with a system to which a surfactant or an alcohol-soluble polymer is added. The ratio of the resin particles to the colorant depends on the monomer composition, the particle size of the resin particles and the structure of the colorant, but is preferably about 3 to 10% based on the resin particles. The amount of the solvent is preferably about 3 to 10 times the weight of the resin particles.

The dye used for dyeing is, for example, CI SOLVENT YELLOW (6,9,17,31,35,100,102,103,105) CI SOLVENT ORANGE (2,7,13,14,66) CI SOLVENT RED (5,16,17, 18,19,22,23,143,145,146,1
50,151,157,158) CI SOLVENT VIOLET (31,32,33,37) CI SOLVENT BLUE (22,63,78,83-86,91,94,95,104) CI SOLVENT BREEN (24,25) CI SOLVENT BROWN (3,9) And the like. A coating layer of a charge controlling agent or a release material may be provided on the surface of the dyed particles. As charge control agents, JP-B-41-20153, JP-B-43-27596, JP-B-44-4397, JP-B-45-26
No. 478, metal complex salts of monoazo dyes described in JP-B-55-42752, JP-B-59-7385, salicylic acid, dialkylsalicylic acid, naphthoic acid, Zn in dicarboxylic acid, Metal complexes such as A1, Co, Cr, and Fe; sulfonated copper phthalocyanine pigments; fluorinated quaternary ammonium salts; and the like. The charge control agent is used in an amount of about 0.5 to 5.0% based on powder particles mainly containing a thermoplastic resin and a colorant.

Examples of the releasing material include low-molecular-weight polyolefins such as low-molecular-weight polyethylene, low-molecular-weight polypropylene, and polyethylene oxide; natural waxes such as beeswax, carnauba wax, and montan wax; stearic acid, palmitic acid, and myristine. Examples include higher fatty acids such as acids, metal salts of higher fatty acids, and higher fatty acid amides. One or more of these can be used, but low molecular weight polypropylene and carnauba wax are preferred. The use amount of these release agents is about 0.5 to 5.0% based on the powder particles mainly composed of a thermoplastic resin and a colorant.

The dispersed polymer particles of the present invention are polymer particles obtained by polymerizing using a fluorine-containing acrylic polymer as a dispersant,
Since the polymer particles thus formed are formed by adsorbing a fluorine-containing acrylic polymer on the surface, the charging characteristics of the polymer particles are negatively charged. Excellent stability. Dispersion polymerization is generally carried out in a non-aqueous solvent, but when forming an electrophotographic toner, an alcohol solvent is preferable in terms of handleability and cost. A polymer that forms a layer that repels steric chemistry is used. In the case of forming dispersion-polymerized particles in alcohol, as a dispersant, a polymer or copolymer of the following monomer is preferable because of its excellent solubility and swellability in an alcohol solvent. That is, 2,2,2-trifluoroethyl acrylate, 2,2,3,3-tetrafluoropropyl acrylate, 2,2,3,3,4,4,5
5-octafluoropentyl acrylate, 2,2
3,3-tetrafluoropropyl methacrylate, 2,
2,3,3,4,4,5,5-octafluoropentyl memethacrylate and the like.

Examples of monomers copolymerized with the above monomers include styrene, vinyl toluene, vinyl chloride, vinyl acetate, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and (meth) acrylic acid. Butyl acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, dodecyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate,
Hydroxypropyl (meth) acrylate, 2-chloroethyl (meth) acrylate, (meth) acrylonitrile,
(Meth) acrylamide, (meth) acrylic acid, vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl methyl ketone, N-vinyl pyrrolidone, N-vinyl pyridine, butadiene and the like.

[0017]

EXAMPLES The present invention will be specifically described below with reference to examples. Production Example-1 7 parts of poly 2,2,2-trifluoroethyl acrylate was dissolved in 150 parts of methanol, and the inside of the reaction vessel was replaced with nitrogen using nitrogen gas. A solution in which 0.82 part of isobutylnitrile is dissolved is added, and the mixture is stirred at 60 ° C. for 8 hours, polymerized, centrifuged, decanted, and the supernatant is removed. 100 parts of methanol is added, stirred for 30 minutes, filtered, and dried. 49 parts of a white powder were obtained. The volume average particle size (Dv) of this powder is 7.36μ
The ratio Dv / Dp to the number average particle diameter (Dp) at m was 1.09.

Preparation Examples 2 to 10 Instead of the styrene and n-butyl acrylate monomers and poly 2,2,2-trifluoroethyl acrylate dispersant of Preparation Example 1, the monomers and dispersants of Table 1 were used. Polymerization was carried out in the same manner as in Production Example 1 except for the use, and the results in Table 1 below were obtained.

[0019]

[Table 1] (Note) St: styrene, nBMA; n-butyl acrylate, 2EHMA; 2 ethylhexyne methacrylate,
MA: methyl acrylate, AA: acrylic acid, TFE
A; 2,2,2-trifluoroethyl acrylate, T
FPA; 2,2,3,3, tetrafluoropropyl acrylate, VAc; vinyl acetate, OFPA;
3,3,4,4,5,5-octafluoropentyl acrylate, TFPMA; tetrafluoropropyl methacrylate, OFPMA; 2,2,3,3,4,4
5,5-octafluoropentyl methacrylate, HE
MA; hydroxyethyl methacrylate, HPMA;
Hydroxypropyl methacrylate.

Comparative Production Example 1 15 parts of polyacrylic acid was dissolved in 150 parts of methanol, and the inside of the reaction vessel was replaced with nitrogen using nitrogen gas.
A solution prepared by dissolving 0.82 parts of azoheath isobutylnitrin was added to the mixture, and the mixture was stirred at 60 ° C. for 8 hours to carry out polymerization. After standing at room temperature for 24 hours, the supernatant was decanted, and the supernatant was removed. After stirring for minutes, the mixture was filtered and dried to obtain 49 parts of a white powder. The volume average particle size (Dv) of this powder is 7.36 μm, and the ratio to the number average particle size (Dp) is Dv / Dp
Was 1.09.

Example 1 A mixture of 100 parts of the resin of Production Example 1 and 7 parts of carbon and 2 parts of spiron black TRH was heated and kneaded with a hot roll to obtain a toner having a volume average particle diameter of 7.5 μm. This developer was placed in a magnetic brush developing device, and the electrostatic latent image formed on the selenium photoreceptor by a normal electrophotographic method was developed, transferred to paper, and fixed to obtain a clear black image.

Example 2 400 parts of methanol was added to 100 parts of the resin obtained in Production Example 2, and the mixture was stirred. At an internal temperature of 40 ° C., 3 parts of Oil Yellow 3G (manufactured by Orient Chemical Co.) was added. Stirring was continued for an hour for dyeing. Then, the mixture was cooled to room temperature and filtered to obtain a yellow powder. 100 parts of an iron powder carrier was mixed with 3 parts of the yellow powder to prepare a developer. This developer was placed in a magnetic brush developing device, and the electrostatic latent image formed on the selenium photoreceptor by a normal electrophotographic method was developed. When this was transferred to plain paper, a yellow copy image having excellent resolution was obtained. Obtained. In order to examine the environmental stability of charging, the charging performance of the above developer was measured at high humidity (30 ° C-90 ° C) and low humidity (10 ° C-15%).
It was 27 μc / g and -25 μc / g at low temperature, and the environmental stability of charging was good.

Example 3 Example 2 was repeated except that SOT RED3 (manufactured by Hodogaya Chemical) was used instead of the resin of Production Example 3 in place of the resin of Production Example 2 in Example 2, and Oil Yellow 3G. Dyeing was performed in the same manner as described above to obtain a red powder. Example 2 using this red powder
In the same manner as in the above, the chargeability of the developer was −24 μc / g at high humidity, −22 μc / g at low temperature, and the ratio was 1.09, indicating good environmental stability.

Example-4 Instead of the resin of Production Example-2 of Example-2, the resin of Production Example-4, and WAXOLINE BLUER P instead of Oil Yellow 3G
Dyeing was performed in the same manner as in Example 2 except that FW (manufactured by ICI) was used, and a blue powder was obtained. Using this blue powder, a developer was prepared in the same manner as in Example 2, and copying was performed to obtain a clear blue image. The chargeability of this developer was -29 µc / g at high humidity and -27 µc / g at low humidity, and the ratio was 1.07, indicating good environmental stability.

Example-5 The resin of Production Example-5 was used instead of the resin of Production Example-2 of Example-2, and the oil black 86 was used instead of the oil yellow 3G.
Dyeing was carried out in the same manner as in Example 2 except that 0 (manufactured by Orient Chemical Co., Ltd.) and MACROLEX ORANGER were used, to obtain a black powder. Using this black powder, a developer was prepared in the same manner as in Example-2, and copying was performed to obtain a clear black image. Further, as a result of a repeated copying test of 10,000 sheets using this developer, a copied image in which the line image and the photographic image were stably maintained during the test was obtained. The chargeability of this developer was -20 .mu.c / g at high humidity and -23 .mu.c / g at low humidity, and the ratio was 1.13, indicating good environmental stability.

Examples 6 to 10 and Comparative Example 1 A developer was prepared using the resins shown in Table 2 and under the same conditions as in Example 5, and the charging properties were examined. The results are shown in Table-2.

[0027]

[Table 2]

[0028]

According to the toner having the constitution of the present invention, a negatively charged toner having excellent environmental stability, a narrow particle size distribution, a small particle size, and a high quality and high durability toner can be obtained.

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 9/08

Claims (3)

(57) [Claims] 1. An electrophotographic toner comprising a thermoplastic resin and a colorant as main components, wherein the thermoplastic resin is a dispersion polymer particle obtained by polymerizing a fluorine-containing acrylic polymer as a dispersant. Electrophotographic toner. 2. The method according to claim 2, wherein the fluorine-containing acrylic polymer is
2,2,2-trifluoroethyl acrylate, 2,
2,3,3-tetrafluoropropyl acrylate,
2,2,3,3,4,4,5,5-octafluoropentyl acrylate, 2,2,3,3-tetrafluoropropyl methacrylate, 2,2,3,3,4,4,5
2. The electrophotographic toner according to claim 1, wherein the toner is a polymer or copolymer of a monomer selected from 5-octafluoropentyl methacrylate. 3. A step of dissolving a fluorine-containing acrylic polymer in a hydrophilic organic solvent, wherein the polymer is dissolved in the hydrophilic organic solvent in the solution, and the resulting polymer is swollen in the hydrophilic organic solvent. An electrophotographic toner comprising a step of polymerizing by adding one or more kinds of vinyl monomers which are hardly or not dissolved, and a step of dyeing the formed polymer with a dye.