KR20060122512A - Preparation method of toner having micro radius - Google Patents

Abstract

A preparation method of toner containing micro particles with uniform spherical form and even particle diameter is provided to form the toner capable of embodying high resolution in an electro-photographically imaging device by employing simple emulsion-polymerization process. The method comprises the steps of: preparing a coloring dispersion by blending a coloring agent and a dispersing agent in distilled water; preparing an organic phase by lending monomer and wax under heating; and preparing toner particles by admixing the coloring dispersion and the organic phase, adding polymerization initiator to the admixture, and polymerizing the admixture with the coloring agent particles as seeds. The resulting toner particles have particle size ranging from 0.1 to 1 mum. Amounts of the coloring agent range from 1 to 30 phr while amounts of the wax range from 1 to 30 phr. Also, contents of the polymerization initiator range from 1 to 5 phr.

Description

Preparation method of toner having micro radius

 The present invention relates to a toner manufacturing method having a fine particle size. More specifically, the present invention relates to a toner manufacturing method capable of manufacturing a toner having a fine particle diameter capable of high resolution when used in an electrophotographic image forming apparatus by a simple process using an emulsion polymerization reaction.

Electrophotographic image forming apparatuses include a facsimile, LDE (light emitting diode), LCS (liquid crystal shutter) printer, digital printer, laser printer or laser copier. The toner composition, which is a developer of the electrophotographic image forming apparatus, generally includes a colorant, a binder resin, a charge control agent, and other functional additives.

Colorants can be broadly classified into dye-based colorants and pigment-based colorants. Among them, pigment-based colorants are more commonly used as colorants for toners because they are advantageous in thermal stability and light resistance than dye-based colorants.

The binder resin accounts for about 90% of the toner as a whole and serves to fix the toner particles onto the recording medium. There are various polymer materials that can be used as the binder resin, and in particular, a latex form of a colloidal gel in which the second component is dispersed in a particulate form can be used as the binder resin.

The charge control agent is used to control the amount of charge charged to the toner particles, and a metal azo compound, a salicylic acid metal complex, nigrosine, a quaternary ammonium salt, and the like can be used.

Among the functional additives added to the toner, there is a releasing agent as an additive for improving the release property. The release agent improves releasability between the roller and the toner when the toner image is transferred to and fixed to the recording medium to prevent toner offset, and the toner causes the recording medium to stick to the roller, causing the recording medium to jam. It is added to the toner composition to prevent it.

As the release agent, low molecular weight polyolefins, silicones having a softening point by heating, fatty acid amides, waxes and the like can be used.

In the electrophotographic image forming apparatus, the size of the toner particles affects the resolution of the final printed image. The more uniform and spherical the toner particles are, the smaller the particle size can realize the high resolution of the final printed image. Recently, there is a growing interest in manufacturing toners of fine particles capable of realizing high resolution according to industrial demands for high resolution images.

The production method of the dry toner for an electrophotographic image forming apparatus can be roughly divided into a pulverization method and a polymerization method, and the polymerization method can be further divided into a suspension polymerization method and an emulsion polymerization method. The pulverization method is difficult to produce toner particles in a spherical shape or a uniform size in the manufacturing process, and toner production by suspension polymerization method also has a limitation in producing toner of fine particles due to the limitation of suspension.

In general, a method of preparing a toner by an emulsion polymerization method is performed by preparing an emulsion of a toner component having a particle size of less than 1 μm, that is, a binder resin, a colorant, a mold release agent, and the like, followed by agglomeration with a flocculant and then 1 μm. Primary aggregation is carried out to a size of 3 μm. Next, secondary agglomeration with latex having a different molecular weight produces particles having a size of 5 μm to 15 μm, which is a general toner particle size.

Such a manufacturing method includes a toner manufacturing method disclosed in US Pat. No. 6,120, 967 and a toner manufacturing method disclosed in US Pat. No. 5,863,696. In the method disclosed in the patent, latexes are combined with pigments and wax emulsion particles using a flocculant. In this case, 100 nm to 200 nm sized latex is first aggregated to 1 μm to 3 μm, and then secondary aggregation or primary There is a problem that the process is difficult, such as to produce spherical particles through the melting process after aggregation. In addition, the process of flocculation and / or melting is complicated and the process has many technical difficulties in controlling the particle size and sphericalizing the particles. In particular, the melting process has to go through a heating process of at least 2 to 4 hours, there is a disadvantage that the entire process is long.

Therefore, there is a continuous demand for a method for producing a toner having spherical fine particles in a simple process.

 SUMMARY OF THE INVENTION The present invention has been made to meet the above requirements, and an object of the present invention is to prepare a toner having a spherical uniform fine particle diameter by using an emulsion polymerization reaction of the components of the toner composition to produce an electrophotographic image forming apparatus. It is to provide a toner manufacturing method that can realize a high resolution upon use.

Toner manufacturing method having a fine particle size according to the present invention for achieving the above object comprises the steps of preparing a colorant dispersion by mixing a colorant and a dispersant in distilled water;

Heat mixing the monomers and the wax to prepare an organic phase; And

And mixing the colorant dispersion with the organic phase and adding a polymerization initiator to polymerize the colorant particles with a seed to produce toner particles.

It is preferable that the manufactured toner particles have a particle size of 1 m or less.

The content of the colorant is in the range of 1 phr to 30 phr,

The content of the wax is in the range of 1 phr to 30 phr, and

The content of the polymerization initiator is preferably used within the range of 1phr to 5phr.

In preparing the toner particles, the polymerization reaction is preferably performed for about 5 to 24 hours.

In the preparing of the toner particles, the polymerization reaction is preferably performed at a temperature within the range of about 50 ° C to about 80 ° C.

Hereinafter, the present invention will be described in more detail with reference to Examples according to the present invention.

The dry toner composition used in the electrophotographic image forming apparatus generally includes colorants, charge control agents, binder resins, and other additives, which are constituents, mixed in a constant composition to form toner particles. In order to realize a high resolution printed image, the dots to be printed must be uniform and their sizes are small. Therefore, the toner particles to be used are spherical and have a uniform and fine size.

In order to prepare a toner having a fine particle size of the present invention, a colorant dispersion is prepared by first mixing a colorant and a dispersant in distilled water.

It is preferable that a coloring agent uses a pigment type coloring agent.

Pigments which can be used in the present invention include, for example, organic pigments including azo pigments, phthalocyanine pigments, basic dye pigments, quinacridone pigments, dioxazine pigments and condensed azo pigments; Carbon black; And inorganic pigments including chromate, ferrocyanide, oxide, sulfide selenide, sulfate, silicate, carbonate, phosphate and metal powder; One or two or more selected from among them may be selected and used, but the usable pigment is not limited thereto. In particular, it is preferable to use an organic pigment in consideration of environmental factors. use.

Examples of the organic pigment that can be used in the present invention are as follows.

Copper phthalocyanine, CIPB (CIPigment Blue) 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 16 (metal free phthalocyanine) or phthalocyanine with aluminum, nickel or vanadium as the center metal, Blue and / or green pigments such as bridged non-phthalocylic dimers / oligomers such as Si-bridged phthalocyanine; Orange pigments such as P.O. 5, 13, 34, 36, 43, 62, 71, 72 and the like; Yellow pigments such as P.Y. 12, 17, 74, 83, 93, 122, 146, 155, 180, 174, 185; P.R. Red pigments such as 48, 57, 122, 146, 147, 176, 184, 186, 202, 207, 238, 254, 255, 269, 270, 272 and the like; Purple pigments such as P.V.1, 19, 23; Mixed pigments such as P.V.19 / P.R.122 or P.R.146 / 147; Etc.

 The dispersant that can be used in the present invention may be a water-soluble polymer, a surfactant, an inorganic compound, or the like, but a surfactant is mainly used. Examples of the surfactant usable as the dispersant in the present invention include anionic surfactants including sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, sodium dodecylnaphthalene sulfate, dialkyl benzenealkyl, sulfates, sulfonates; Dialkyl benzenealkyl ammonium chloride, alkyl benzyl methyl ammonium chloride, alkyl benzyl dimethyl ammonium bromide, benzalkonium chloride, cetyl pyridinium bromide, dodecylbenzyl triethyl ammonium chloride, lauryl amine acetate, stearyl amine acetate, and lauryl Cationic surfactants including trimethyl ammonium chloride; Zwitterionic surfactants including lauryl dimethylamine oxide; And polyvinyl alcohol, polyacrylic acid, metarose, methyl cellulose, ethyl cellulose, propyl cellulose, hydroxyethyl cellulose, carboxy methyl cellulose, tristyrylphenol ethoxylate phosphate ester, polyoxyethylene cetyl ether, polyoxyethylene la Uryl ether, polyoxyethylene octyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene oleyl ether, polyoxyethylene sorbitan monolaurate, polyoxyethylene stearyl ether, polyoxyethylene nonylphenyl ether, dialkylphenoxy Nonionic surfactants containing poly (ethyleneoxy) ethanol; may be used by mixing one or two or more selected from the group consisting of. However, the surfactant that can be used in the present invention is not limited thereto.

Examples of commercially available surfactants include products such as Dowfax, Tergitol, Triton, etc. of Dow Chemical.

As the distilled water in which the monomer and the surfactant will be dispersed, ultrapure water is used. Ultrapure water is used by deoxygenation by bubbling with nitrogen gas.

The milling equipment is used to disperse the pigment and dispersant described above in ultrapure water. Milling equipment that can be used for milling is ball mills, dyno mills, EIGER MILL 250, or Dispermat. Using this milling equipment, a colorant dispersion is prepared by milling with glass beads for 1 to 5 hours at a rotational speed of 2000 rpm to 10000 rpm.

In the prepared colorant dispersion, the colorant acts as a seed of the polymerization reaction in the production step of the toner particles described later.

Apart from the preparation of the colorant dispersion, the organic phase is prepared by heating and mixing the monomer and the wax.

Monomers are radically polymerizable monomers, styrene-based monomers including styrene, methylstyrene, chlorostyrene, dichlorostyrene, p-terr-butylstyrene, p-n-butylstyrene and p-n-nonylstyrene; Acrylate, methyl acrylate, ethyl acrylate, propyl acrylate, isobutyl acrylate, n-butyl acrylate, beta carboxy ethyl acrylate, hydroxy acrylate, ethylhexyl acrylate, methacrylate, methyl methacrylate (Meth) acrylic acid ester monomers including ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, hydroxyethyl methacrylate and ethylhexyl methacrylate; Monomers having a carboxyl group including acrylic acid, itaconic acid, methacrylic acid, maleic acid, fumaric acid and cinnamic acid; Monomers having sulfonic acid groups including sulfonated styrene; Amino styrene and quaternary ammonium salts thereof; Monomers containing nitrogen-containing hetero rings including vinylpyridine and vinylpyrrolidone; One or two or more selected from the group consisting of acrylonitrile, butadiene, isoprene, and divinylbenzene may be selected and used. However, the monomer which can be used for this invention is not limited to this.

Waxes that may be used in the present invention include, for example, carnauba wax, vegetable natural waxes and beeswax including bayberry wax, shellac wax, and superma Natural waxes including animal natural waxes including Supermaceti wax; Mineral waxes including Montan wax, Ozokerite wax, Ceresin wax; Petroleum waxes including paraffin wax, microcrystalline wax; And synthetic waxes including Fischer-Tropsch wax, polyethylene wax, polypropylene wax, acrylate wax, fatty acid amide wax, silicone wax, and polytetrafluoroethylene wax. Or two or more types can be mixed and used, but it is not limited to this.

The monomer and wax are heated and melted together to produce an organic phase, which is then homogeneously prepared using a homogenization equipment. Homogenizers that can be used in the present invention include homogenizers, homomixers, pressurized kneaders / coaters, extruders and media dispersers, ball mills with media, sand mills and dynomils, and the like. Homogenization time runs in the range of 1 to 60 minutes. Homogenize at a rotational speed of approximately 1000 rpm to 7000 rpm.

It is preferable to further add a chain trnasfer agent in the preparation of the organic phase, which is a functional additive added to control the target molecular weight of the polymer finally formed by polymerization.

Chain transfer agents that can be used in the present invention, for example, octyl mercaptan (octyl mercaptan), dodecyl mercaptan (dodecyl mercaptan) and the like, in addition to the chain transfer agent commonly used in the art to which the present invention belongs without limitation Can be used.

The colorant dispersion prepared as described above and the organic phase are put together in a reactor and mixed with stirring at a rotational speed of about 100 rpm to 800 rpm. The inside of the reactor is heated to about 50 ° C. to 90 ° C. with stirring. When the temperature inside the reactor is about 50 ° C. to 80 ° C., the polymerization initiator is slowly dropped using a dropping funnel and purged inside the reactor with nitrogen gas. The reaction time is about 5 to 24 hours to proceed with the reaction.

 The polymerization initiator may be classified into a water-soluble initiator and a fat-soluble initiator, and the polymerization initiator usable in the present invention uses a water-soluble polymerization initiator, although there is no particular limitation. Examples of water-soluble polymerization initiators that can be used include potassium persulfate, ammonium persulfate, benzoyl peroxide, lauryl peroxide, sodium persulfate and hydrogen peroxide. (hydrogen peroxides), t-butyl hydroperoxide, cumene hydroperoxide, para-mentane peroxides and peroxy carbonates. One or two or more of these may be selected and mixed. However, the polymerization initiator which can be used is not limited to this.

It is preferable to adjust the content of the colorant dispersion so that the content of the colorant contained in the toner composition through the colorant dispersion is within the range of 1 phr to 30 phr. If the content of the colorant is less than 1 phr, it is difficult to realize the color of the printed image and it is difficult to function as a seed for the polymerization reaction. In addition, if the content is greater than 30phr it is not preferable because the dispersibility is inferior.

Herein, the unit representing the content, phr, is an abbreviation of part per hundreds of resin and represents the mass unit of the target additive for 100 parts of the resin.

The content of the wax contained in the toner composition through the organic phase is preferably in the range of 1 phr to 30 phr. If the content of the wax is less than 1 phr can not function as a release agent, if larger than 30 phr because the dispersibility is poor.

The content of the polymerization initiator for the polymerization reaction is preferably in the range of 1 phr to 5 phr, which is determined by the content of the additives participating in the polymerization reaction.

The toner particles thus prepared are prepared using an emulsion polymerization reaction without agglomeration or melting, and thus the size of the particles can be finely controlled, and a uniform spherical particle shape can be realized by emulsion polymerization. The particle size of the finally produced toner particles is preferably 1 占 퐉 or less, and therefore, the content of the components added to the polymerization reaction is adjusted so as to be toner particles of this particle size.

Hereinafter, the present invention will be described in more detail with reference to Examples according to the present invention.

{Example}

Example  One

A colorant dispersion was prepared by milling 30 g of P.B.15: 3, 100 g of ultrapure water and 10 g of Dowfax with 200 g of glass beads at a speed of about 3000 rpm for 1 hour using a dispermat.

Meanwhile, an organic phase was prepared by mixing 100 g of a monomer mixture in which styrene, butyl acrylate, and acrylic acid were mixed at 7: 2: 1, 1 g of 1-dodecanethiol, and 10 g of ester wax while heating with ultrasonic (Ultrasonic). The prepared organic phase was placed in 350 g of ultrapure water and 30 g of the prepared colorant dispersion was mixed and placed in a reactor.

The polymerization initiator solution was added to the mixed solution of the reactor described above, and then mixed, and homogenized at 7000 rpm for 10 minutes using IKA Ultra Terex. This mixture was then heated to 80 ° C. with stirring at 100 rpm.

When the internal temperature of the reactor reached 80 ° C, a small amount of ammonium peroxide sulfate was added, and the inside of the reactor was purged with nitrogen gas.

The reaction time was about 5 hours, and after the reaction was completed, the heating was stopped and naturally cooled.

The final toner particles thus finished had a volume average particle size of about 670 nm and a number average particle size of about 610 nm.

Example  2

Toner was prepared in the same manner as in Example 1, except that Carnauba wax was used instead of ester wax in Example 1. The final toner particles thus prepared had a volume average particle size of about 480 nm and a number average particle size of about 350 nm.

Example  3

Instead of using P.B.15: 3 in Example 1 above, P.Y. Toner was prepared in the same manner as in Example 1, except that 180 was used. The final toner particles thus prepared had a volume average particle size of about 370 nm and a number average particle size of about 310 nm.

Example  4

Toner was prepared in the same manner as in Example 1, except that P.R.122 was used instead of P.B.15: 3 in Example 1. The final toner particles thus prepared had a volume average particle size of about 770 nm and a number average particle size of about 630 nm.

Example  5

A toner was manufactured in the same manner as in Example 1, except that Nipex 70, which is carbon black, was used instead of P.B.15: 3 in Example 1. The final toner particles thus prepared had a volume average particle size of about 360 nm and a number average particle size of about 330 nm.

According to the present invention as described above, it is possible to produce fine toner particles having a particle size of micron or less through a simple manufacturing process without a separate agglomeration or melting process using only an emulsion polymerization reaction, and in this way a uniform spherical shape When a toner having a fine particle size of is used and used in an electrophotographic image forming apparatus, high resolution can be realized. In particular, the present invention has an effect of improving the dispersibility of the colorant because the polymer is used as a seed to produce a polymer that is a binder resin of the toner particles.

Although the above has been illustrated and described with respect to the preferred embodiment of the present invention, the present invention is not limited to the specific preferred embodiment described above, the present invention without departing from the gist of the invention claimed in the claims Various modifications can be made by those skilled in the art, and such changes are within the scope of the claims.

Claims (5)

Mixing a colorant and a dispersant in distilled water to prepare a colorant dispersion; Heat mixing the monomers and the wax to prepare an organic phase; And And mixing the colorant dispersion with the organic phase and adding a polymerization initiator to polymerize the colorant particles with a seed to produce toner particles. 2. The method of claim 1, The prepared toner particles have a particle size of 0.1 μm to 1 μm, wherein the toner composition has a fine particle size. The method of claim 1, The content of the colorant is in the range of 1 phr to 30 phr, The content of the wax is in the range of 1 phr to 30 phr, and The content of the polymerization initiator is a method for producing a toner composition having a fine particle size, characterized in that used within the range of 1phr to 5phr. The method of claim 1, In the preparing of the toner particles, the polymerization reaction is performed for about 5 to 24 hours. The method of claim 1, In the preparing of the toner particles, the polymerization reaction is performed at a temperature within a range of about 50 ° C to about 80 ° C.