KR100453149B1 - Compositions and method of producing toner for development of latent electrophotogrphic images by way of dispersion comminution - Google Patents

Abstract

The present invention provides a first resin composition comprising a polymer resin, a processing aid, a colorant, and optionally a charge control agent, and then comprises an organic solvent and a surfactant, wherein the first resin composition is in an insoluble organic medium for the resin. And dispersing the first resin composition by heating and shearing in the organic medium to form resin fine particles, and then heating the pulverized resin fine particles to vaporize the processing aid to produce a fine particle toner. A method for producing a particulate toner for electrostatic latent image development by separating and recovering the particulate toner from a medium, wherein the high-resolution color combines excellent properties for forming an electrophoretic imaging system by forming spherical toner particles having a small particle diameter. It is to provide a toner manufacturing method.

The fine particle toner manufacturing method of the present invention is characterized by being able to produce fine particle toner at a lower temperature by using a processing aid, not only high molecular weight resin can be used, but also having desirable charging characteristics due to rough surface properties.

Description

A method for producing a particulate toner composition for electrostatic latent image development by solvent pulverization and its toner composition {Compositions and method of producing toner for development of latent electrophotogrphic images by way of dispersion comminution}

The present invention relates to a toner composition for electrostatic latent image development, such as electrophotographic, electrostatic lock, and electrostatic printing, and a method for producing toner. More specifically, the present invention relates to a method for producing resin particles of suitable size comprising high resolution color electrophotographic, electrostatic rock, colorants and other components for use in electrostatic printing. The present invention is associated with US patent application Ser. No. 09 / 571,772, filed May 16, 2000, which is incorporated herein by reference.

Methods of developing and forming images on the surface of photoconductive materials by electrostatic methods are well known. Basic electrophotographic imaging (US Pat. No. 2,297,691) induces a uniform electrostatic charge on a photoconductive insulating layer known as a photoconductor or photoreceptor, exposes the photoreceptor to light and then masks the image from the light to After dissipating the charge in the portion that has been exposed to light, the electrostatic latent image generated by depositing a finely divided electroscopic toner material on the image is developed. These toners are usually attracted to the portion that holds the charge of the photoreceptor, forming a toner image corresponding to the electrostatic latent image. The developed image is transferred to a substrate such as paper. The shifted image is then permanently fixed to the substrate via a combination of heating, pressurization, heat pressurization or other suitable fixing method such as solvent treatment or protective coating treatment.

Also known is the technique of developing such electrostatic images. The developer is a carrier in which charged color toner particles are dispersed. The photoreceptor containing the electrostatic latent image is in contact with the developer. Charged toner particles in the developer are moved to the charged region of the photoreceptor through the contact to develop a latent image. The photoreceptor is then developed as the charged color particles adhere to the latent image in the form of an image. The developed image is typically transferred to a suitable substrate, such as paper, transparent film, and can optionally be fixed to the substrate by heating, pressing or other suitable method.

Toner and developer compositions comprising colored particles are well known. See, for example, U.S. Pat. Can be. Conventional compositions typically include toner particles composed of colorants and synthetic resins, waxes or polyolefins, charge control agents, rheology enhancers and other additives. Typical toner compositions include about 90 to 95 weight percent resin, about 2 to 10 weight percent colorant, 0 to about 6 weight percent wax, 0 to about 3 weight percent charge control agent, and about 0.25 to 1 weight percent fluidity Enhancer and 0 to about 1 weight percent of other additives. The main resins used are styrene-acrylic copolymers, styrene butadiene copolymers and polyesters. The colorant is generally selected from cyan dyes or pigments, magenta dyes or pigments, yellow dyes or pigments and mixtures thereof.

Conventional color toners are produced, for example, by the milling method described in US Pat. No. 5,102,761 described above. In this process, the polyacrylate resin is mixed in a melt mixer with pigments, charge control agents and optionally waxes. The polymer is milled mechanically and then milled into small particles. Conventional toner particles typically exhibit irregular shapes and a wide particle size distribution. In order to achieve the optimal resolution of the image and color, the smaller the particle size, the better the performance. Thus, for example, when the average particle diameter is 7 microns or more, it is difficult to obtain a resolution of about 600 dots / inch or more. The particle size must be less than 5 microns for the output image to have a resolution of 1200 dots / inch. Since a large amount of energy is consumed to produce small particles, conventional methods have a narrow and uniform size distribution, and it is difficult to produce particles having a size of 7 to 10 microns or less.

Previous attempts have been made to obtain small particles having a particle size of 7 μm or less. For example, U. S. Patent Nos. 5,352, 521, 5,470, 687, and 5,500, 321 described above disclose methods for producing toner particles by dispersion polymerization. These methods combine monomers (primarily styrene and acrylates) and additives such as pigments, CCA and waxes to form a dispersion. After this dispersion is dispersed in an aqueous or non-aqueous solvent, the monomers are reacted to form toner particles. The advantage of this method over other methods is that small diameter spherical toner particles can be produced in a single process. However, during the polymerization process, the volume of the material decreases, which causes dispersant to be included in the toner particles. In addition, since it is difficult to completely terminate the polymerization, a large amount of monomer remains in the toner particles. Residual monomers and the dispersed solvent included are difficult to separate from the particles. In addition, the polarities of the polymeric materials change rapidly during the polymerization process and additives ooze out of the particle mass and tend to concentrate on the surface. In addition, it is very difficult to remove them from the toner particles when the dispersing stabilizer, the surfactant, and the like remaining on the surface of the toner particles deteriorate the charge characteristics of the toner particles and their stability.

In the specification of US Patent Application Serial No. 09 / 571,772, a method for preparing toner particles by adding a colorant and a charge control agent to a solvent which does not dissolve the resin is disclosed. However, this method has been limited to producing a relatively low molecular weight toner resin, but high temperature and strong shear force are required to produce particles more effectively. Moreover, the toner particles produced by this method usually have a smooth surface structure, and as a result, they tend to lack the property of being able to be charged in a short time which is important in a single component electrophotographic developing system.

The toner composition preferably has a narrow particle size distribution. In general, it is known that the narrower the particle size distribution, the more uniform the charge distribution is possible, and as a result, the line resolution of the printed image is increased and the dots are reduced in the image background. Existing milling methods are inadequate for obtaining a narrow particle distribution and therefore require an additional classification process to remove coarse particles and fine particles from the toner composition that fall outside the desired size range.

The narrow and broad extent of the particle size distribution can be expressed using an 80% span. Span is defined as the ratio of the size difference of the median particle to 80% of the median particle size distribution and the median particle size. A more detailed definition of the span is given later in the description of the physical property measurement method used in the present invention. Therefore, the smaller span value means a narrower size distribution. The span value of the conventional toner composition obtained after the above-described classification process is about 1.2. Therefore, it can be said that a method of producing toner particles having a span value smaller than 1.2 without going through a classification process is very desirable.

SUMMARY OF THE INVENTION An object of the present invention is a method for producing particles using a strong shear condition in a dispersion medium containing a surfactant in a melt of a polymer resin comprising a colorant, a processing aid and other additives, the spherical toner particles having a small particle diameter To provide a high resolution color toner manufacturing method that combines excellent properties for use in electrophotographic imaging systems.

It is still another object of the present invention to provide a color toner manufacturing method which can be produced at a significantly lower temperature than the method described in the invention described in the above-mentioned US patent application Ser. No. 09 / 571,772.

It is still another object of the present invention to provide a method for producing a toner more efficiently by using a resin having a significantly higher molecular weight.

It is still another object of the present invention to provide a method for producing toner particles having a diameter of 1 to 10 mu m and comprising a resin having a narrow particle size distribution, a colorant and optionally a charge control agent.

Another object of the present invention is to provide a method for producing toner particles having a spherical but rough surface structure.

It is still another object of the present invention to provide a toner manufacturing method which has fast charging characteristics and is therefore suitable for a single component electrophotographic developing apparatus.

Other objects and advantages of the present invention will become apparent from the following description and examples.

In order to achieve the above object, in the present invention, a method for producing a fine particle toner composition for electrostatic latent image development by a solvent grinding method,

(a) preparing a first resin composition comprising a polymeric resin, a processing aid, a colorant, and optionally a charge control agent, (b) an organic medium comprising an organic solvent and a surfactant and insoluble in the resin; 1) dispersing the resin composition, (c) pulverizing the first resin composition by heating and shearing action in the organic medium to form resin fine particles, (d) heating the pulverized resin fine particles to the processing aid A method of producing a particulate toner composition for electrostatic latent image development, comprising the steps of: producing a particulate toner by vaporizing; and (e) separating and recovering the particulate toner from the organic medium.

In addition, the present invention is a resin composition comprising a polymer resin, a processing aid, a colorant, and optionally a charge control agent in the organic medium insoluble to the resin by pulverization by heating and shearing action to form the fine resin particles, and then the processing aid A particulate toner composition prepared by vaporizing and separating and recovering from an organic medium,

i) the shape of the particles is spherical, ii) the volume average diameter of the particles is in the range of 1 to 10 μm, i) the span value is 1.0 or less, and i) the weight average molecular weight of the resin component is from 3,000 g / mol to It provides a particulate toner composition, characterized in that the range of 100,000g / mol.

In addition, the present invention may optionally further comprise mixing wax or fumed silica particles to improve flowability of the toner particles.

First look at each component of the present invention in detail as follows.

1) Polymer resin

The resin used in the present invention is generally an amorphous resin having a glass transition temperature in the range of about 40 ° C. to about 90 ° C., with polyester resins and styrene copolymer resins being particularly preferred. When the processing aid is used, the molecular weight range of the polymer resin available for toner production can be increased, and the molecular weight of the polymer resin usable is in the range of 3000 g / mol to 100,000 g / mol. The polymer resin may optionally include a functional group to improve the compatibility of the portion of the polymer chain with the colorant.

Examples of such resins include polyamides, polyolefins, styrene acrylates, styrene methacrylates, styrene butadienes, styrene polymers with crosslinked structures, ethylene-cycloolefin copolymers, epoxides, polyurethanes, single components or two or more vinyl monomers. Vinyl resins including copolymers, and the like, and polyesters obtained through esterification of dicarboxylic acids with diols of diphenols as exemplified in US Pat. No. 3,590,000 and similar patents. Of these resins, polyester copolymers and styrene copolymers are particularly preferred.

The resin is selected from the group consisting of hydroxy group, alkoxy group, phosphonic group or phosphonic derivative, phosphonic group or phosphonic derivative group, thiol group, amine group, alkylamine group, quaternary amine group and mixtures thereof, It may have a functional group suitable for interacting with the dye.

The weight average molecular weight of the resin has a value in the range of 3,000 g / mol to 100,000 g / mol as measured by gel absorption chromatography (GPC), and more preferably has a value within 5,000 g / mol to 20,000 g / mol. Do. The molecular weight distribution (Mw / Mn) of the linear polymer generally has a value in the range of 1.5 to 6, but preferably has a value of 2 to 4. The temperature at which the glass transition temperature of the linear polymer measured by the calorimetry (DSC) starts is generally in the range of 50 ° C to 90 ° C, but is preferably in the range of 50 ° C to 70 ° C.

2) Processing aid

The processing aid, which can be said to be a component of the present invention, is selected from organic solvents having a boiling point of 200 ° C. or less that can be easily absorbed by the polymer resin component. The use of a processing aid lowers the melting temperature of the first resin composition, thus allowing the entire manufacturing process to be carried out at a lower temperature than without the processing aid. The processing aid is preferably insoluble in the organic solvent component used in the dispersion process, and examples thereof include acetone, dimethylformamide, cyclohexane, dimethyl sulfoxide, chlorobenzene and the like.

3) colorant

Colorants used in the present invention are pigments commonly used commercially. Representative black pigments include carbon black, aniline black, nonmagnetic ferrite and magnetite. Representative cyan pigments include copper phthalocyanine compounds, copper phthalocyanine derivatives, anthraquinone compounds, and basic pigment chelate compounds. C.I. Pigment Blue 1, 7, 15, 151, 152, 153, 154, 60, 62, 66 pigments are particularly preferred. Representative magenta pigments include condensates of azo compounds, diketopy pyropyrrole compounds, anthraquinone compounds, quinacridone compounds, basic pigment chelate compounds, naphthol compounds, benzimidazole compounds, thioindigo compounds, perylene compounds and the like. But C.I. Pigment Red 2, 3, 5, 6,7, 23, 483, 483, 484, 811, 122, 146, 166, 169, 177, 184, 185, 202, 206, 220, 221, 254 Pigments are particularly preferred Do. Typical yellow pigments include condensates of azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, allylamide compounds, and the like. However, C.I. Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 109, 110, 11, 128, 128, 147, 168, 180 pigments are particularly preferred.

The weight ratio of the pigment and the polymer resin is generally in the range of 1: 100 to 10: 100, but preferably 1 to 10% by weight.

The colorant is selected in consideration of hue, saturation, lightness, weather resistance, transparency, dispersion degree in toner resin, and the like. The colorant may be used alone or in a mixture or in a solid solution. In order to increase the degree of dispersion in the toner resin, the colorant particles may be coated with a polymer film.

4) Charge control agent

Positive or negative charge control agents suitable for the present invention may be added, which may generally be infused at a rate of 0% to 10% by weight, but more preferably from 1% to 3%. Examples using alkyl pyridinium halide, alkyl pyridinium compounds are illustrated in US Pat. No. 4,298,672, and organic sulfate, sulfonate compounds are illustrated in US Pat. No. 4,338,390. In addition, US Pat. No. 5,114,821 describes various examples, in which bisulfonate, ammonium sulfate, distearyldimethyl ammonium bisulfate, and the like are used, such as cetyl pyridinium, tetrafluoroborate, and distearyl dimethyl. When using aluminum salts such as ammonium methyl sulphate, BONTRON E-84 or E-88 and when mixing a known charge control agent such as distearyl dimethylammonium bisulfate or ammonium sulfate as an agent to improve the properties of the charge Included. Effective internal or external charge control agents can be selected and used from those described in the foregoing patent specification.

5) Other additives-waxes or fumed silica

The toner composition of the present invention may be added an additive such as wax or fumed silica.

Wax helps toner toner and removes ghost image. Ghost image refers to a phenomenon in which a toner is fused in an unwanted place when printed on a substrate. The process in which the toner is printed on the paper is first shown in the present specification, and the toner is first transferred onto the opc drum, and the transferred toner is again moved by the electrostatic attraction on the paper. At this stage, the toner is only physically on the paper. Therefore, the position of the toner may change when a physical force is applied. The toner is fixed on the paper while passing through a hot fusing roll. At this time, in the process of toner melting on paper, some toner may cause unwanted reverse transition to the fusion roll. It is a ghost image that the toner reversed to the fusion roll appears in another position while rotating. When using a toner in which wax is added, the reverse transition may be suppressed by the releasing property of the wax.

Generally, low molecular weight waxes such as polypropylene and polyethylene can be added, and such materials can be purchased and used commercially from EPOLENE N-15 ^™ or Eastman Chemical Products. The molecular weight of commercially available polyethylenes ranges from 1,000 g / mol to 1500 g / mol, but the molecular weight of polypropylenes that can be used in the present invention can range from 4,000 g / mol to 7,000 g / mol.

The use of silica is as follows. In general, the smaller the size of the powder is, the more physical agglomeration occurs, which is due to van der Waals forces formed between the powders. The best way to control this is to maintain a constant distance between the powders. When very small particles, such as silica, are coated around the toner particles, the silica particles physically adhere to the particles by van der Waals forces, thereby maintaining a constant distance between the toners. In addition, since the silica particles are generally spherical, they have a good rolling property such as bearings. For this reason, silica coated toners have fluid-like fluidity, which is a representative example of the fluidity improver described below.

6) organic medium

Effective dispersion and production of particles are made possible when using organic solvents that do not dissolve the resin. More specifically, it is easy to apply that the difference between the solubility index of the solvent and the solubility index of the resin particles is 1 or more, and more preferably 2 or more. Any organic medium may be used as long as it does not dissolve the resin component. Particularly preferred are solvents containing paraffinic solvents and poly (ethylene glycol). For example, it is preferable to use a nonpolar solvent having a low solubility index such as paraffin, paraffin ester, paraffin amide, and paraffin ether together with the polyester particles. . On the other hand, when a solvent having a relatively high polarity such as water, methanol, propanol and acetone is selected as the solvent of the dyeing process, coalescence of particles occurs remarkably. On the other hand, when a nonpolar resin, such as a styrene copolymer, is dispersed, it is preferable to use a polar organic solvent such as polyethylene glycol having a number average molecular weight of less than 1,000. When nonpolar solvents such as paraffin, paraffin ester, paraffin amide, and paraffin ether are used in the dispersion process of the styrene copolymer, a remarkable coalescence phenomenon occurs.

7) surfactant

Surfactants are used in the dispersion process together with the aforementioned organic solvents and serve two important functions for the successful production of small particles. Firstly, the surfactant prevents the resin particles from coalescing during the process. The dispersion process in the course of the invention is generally carried out at or near the glass transition temperature of the resin. Thus, in the absence of a surfactant, molten particles tend to coalesce, thereby forming dyed particles unsuitable for high resolution toner. Second, the size of the particles is determined by the relative amount of the surfactant with respect to the resin particles. Surfactants accumulate at the interface between insoluble solvents and molten particles due to their chemical structure. Thus, large amounts of surfactants can be applied to produce small sized particles, while small amounts of surfactants can be applied to produce large particles. The surfactant can be anionic, cationic or nonionic.

Nonionic surfactants can be made using ethylene oxide or propylene oxide. Preference is given to polymer surfactants comprising polyvinyl pyrrolidone, alkylated maleic acid copolymers, polymers comprising ethylene oxide functional groups and copolymers of polymers comprising propylene oxide functional groups. The surfactant may be present in the solvent at 0.2 to 15% by weight, but typically includes 1 to 10% by weight.

8) Fluidity Enhancer

Toner fine particles can be coated with a suitable fluidity enhancer. Flow improvers help to improve the flow of particles to be used as color toners. Suitable fluidity improvers include finely classified hydrophobic silica, titanium oxide, zinc stearate, magnesium stearate and the like. These fluidity improvers are coated on the particles by dry mixing, solvent mixing or the like. In general, fumed silica (available under the trade name Cab-O-Sil from Cabot, Tuscany, Ill.) With a hydrophobic material such as hexamethylsilazene, is added to CCA in a tumble mixer for 10 to 60 minutes. Mixed with the coated particles.

Definition of Terms

1) volume average particle size

The term "volume average particle size (L)" as used herein is defined in pages 3 to 13 of the Power Technology Handbook (K. Gotoh et al., 2nd edition, Marcell Dekker Publications, 1997).

In the particulate toner composition of the present invention, it is preferable that at least about 80% by weight of the total resin particles use particles having a particle size distribution in the range of 0.5 × L to 1.5 × L. This provides toner particles containing a uniform amount of charge in each toner particle, in which resin particles having a narrow particle size distribution are uniformly dyed, and also provide a high quality radiant image, and facilitate charge control at a developing site. Because it makes you.

In the present invention, particle size distribution is measured using a commercial Coulter LS particle size analyzer (Coulter Electronics Co., Ltd., St. Pittsburgh, FL).

2) span value

As an index defining the size distribution of particles, a span value was defined and used as follows. In the size distribution chart, the diameter of the particles corresponding to the volume of 10% was defined as d10, the diameter of the particles corresponding to 90%, d90, and the particle diameter of the 50% distribution corresponding to the average value was defined as d50. The span value obtained using the above three values can be expressed as below.

As can be seen from the definition, the span value is smaller, and the index value indicates the narrower particle distribution, and the larger value, the wider particle distribution.

The surface area of the microsphere resin is obtained from the BET isothermal curve. BET isothermal experiments are measured using a commercially available Automatic Volumetric Sorption Analyzer (Model No. ASAP2000, Micromeritics Instrument Corporation, Norcross, Georgia). The measurement is made in such a way as to determine the amount of nitrogen adsorbed on the particle surface under reduced pressure, the surface area being determined from the plot of pressure and adsorption amount. A detailed description of this is given in the BET isothermal curve section on pages 615-631 of Physical Chemistry of the Surface (New York John Wiley and Sons, A. W. Adamson and A. P. Cast (1997), 6th edition).

3) roughness index

The surface roughness index used in the present invention has a volume average particle size, and is defined as the ratio of the surface area of 1 gram of a perfectly spherical particle and the surface area obtained from the BET isothermal curve. The surface roughness index is expressed by the following equation.

Surface roughness index = (1/6) r * d * A _exp ,

Where r is the polymer density and d is the diameter of the polymer microspheres. The coefficient defined in this way indicates how rough the surface is. The optical density of the printed image was measured using a light density meter (commercially available from Macbeth Company, New Windsor, NY).

Hereinafter, a method of manufacturing the particulate toner of the present invention will be described in detail step by step.

As described above, the method for preparing the particulate toner of the present invention comprises the steps of (a) preparing a first resin composition comprising a polymer resin, a processing aid, a colorant, and optionally a charge control agent, (b) using an organic solvent and a surfactant. Dispersing said first resin composition in an organic medium insoluble in said resin, (c) grinding said first resin composition by warming and shearing action in said organic medium to form resin fine particles, (d) heating the pulverized resin fine particles to vaporize the processing aid to produce a particulate toner, and (e) separating and recovering the particulate toner from the organic medium.

The step a) of preparing a first resin composition of the present invention is performed by melting and kneading a polymer resin, a processing aid, a colorant, and optionally a charge control agent. In this case, in order to effectively mix the resin, the colorant and the charge control agent, a method of melting and mixing in a reactor equipped with a stirrer, a melt kneader method of mixing in a sealed kneader, and a method of melt mixing in a twin screw extruder may be used. Can be.

The amount of the processing aid may vary but is generally used within the range of 5% to 50% by weight, more preferably 10% to 30% by weight. In addition, the colorant is added in a ratio of 1 to 20 based on the resin weight 100.

In step a) of the present invention, the first resin composition may further include an additive such as wax or fumed silica. At this time, the low molecular weight wax that can be used may be present in various ratios in the toner composition, but is generally present in a ratio of 0% by weight to 15% by weight, more preferably 2% by weight to 10% by weight.

The melting temperature of the first resin composition is determined by adjusting the amount of the processing aid included, but the resin composition is preferably prepared at a low temperature.

Step (b) of the present invention comprises dispersing the first resin composition in an organic medium incorporating an organic solvent and a surfactant and insoluble in the resin. One method is carried out by introducing the first resin composition while stirring the organic medium at a temperature above the flow temperature of the first resin composition, and another method comprises a melt of the first resin composition. It is carried out by introducing the organic medium into the vessel while stirring the vessel. At this time, a suitable mixing device may be used in this step, for example, an impeller type stirrer and a device capable of heating the reactant.

During the step of dispersing the first resin composition, the resin composition may be present from about 10% to about 70% by weight of the total organic medium weight, more preferably from about 20 to about 50% by weight of the total organic medium weight.

The organic medium is kept warm during the dispersing of the resin composition, and the temperature can be freely selected in a range satisfying the following two conditions. That is, what is necessary is just to be low enough that a processing composition contained in a resin composition does not vaporize while being high enough that a resin composition has fluidity. Accordingly, the dispersion process of the present invention is generally carried out at or near the glass transition temperature of the resin. Although the operating temperature varies depending on the type and amount of processing aid, a temperature in the range of about 30 ° C to 200 ° C is preferred. In addition, the operating temperature does not necessarily need to be equal to the dispersion temperature. The dispersing process continues until the mixture shows milky white, since milky white means that the resin composition is pulverized into small particles.

(C) The step of pulverizing the first resin composition by heating and shearing action in the organic medium to form resin fine particles is as follows.

The shearing action causes the dispersed resin particles to be pulverized into fine particles, and the surfactant covers the surface of the crushed particles to prevent the pulverized particles from agglomerating back into larger particles. The grinding process into fine particles is continued until the size of the particles reaches an equilibrium value determined by the relative amount of the surfactant and the total resin. When the processing aid is added, the shear force applied in the present invention is significantly smaller than in the case where the processing aid is not used. If the impeller-type stirring device having a radius of 10 cm is stirred at a speed of 100 rpm, effective production is possible, and the process generally proceeds for about 30 minutes to 10 hours.

The step of vaporizing and removing the processing aid of the present invention takes place at a temperature higher than or similar to the boiling point of the processing aid. At this time, the processing aid is evaporated from the resin composition and removed from the reactor. This process can be done more efficiently if the processing aids do not mix with the organic medium. The removal step is stopped when the processing aid is no longer mixed with the vapor from the reactor.

The step of separating and recovering the prepared toner particles of the present invention is performed while cooling the reactor to a temperature lower than the glass transition temperature of the resin composition. The solid particles are then filtered from the organic medium, and various suitable filtration devices can be used. After washing the filtered particles with a low boiling organic solvent such as isohexane, the solvent is lower than the glass transition temperature of the resin composition. Is dried to obtain the final dried particles.

The dispersing, particulate preparation and processing aid removal steps may be carried out discontinuously in the same reactor respectively or may be carried out in superimposition in one reactor.

After the toner fine particles are produced, fumed silica particles may be added to improve the fluidity of the particles, and may be coated with a suitable fluidity improver. Flow improvers help to improve the flow of particles to be used as color toners. Suitable fluidity improvers include finely classified hydrophobic silica, titanium oxide, zinc stearate, magnesium stearate and the like. These fluidity improvers are coated on the particles by dry mixing, solvent mixing or the like. In general, fumed silica (available under the trade name Cab-O-Sil from Cabot, Tuscany, Ill.) With a hydrophobic material such as hexamethylsilazene, is added to CCA in a tumble mixer for 10 to 60 minutes. Mixed with the coated particles.

In another aspect, the present invention is a resin composition comprising a polymer resin, a processing aid, a colorant, and optionally a charge control agent by pulverizing by heating and shearing action in an organic medium insoluble to the resin to form fine resin particles, A particulate toner composition prepared by evaporating the processing aid and separating and recovering it from an organic medium, wherein i) the particles are spherical in shape, ii) the volume average diameter of the particles is in the range of 1 to 10 μm, and i) the span value is 1.0 or less, i) a weight average molecular weight of the resin component is in the range of 3,000 g / mol to 100,000 g / mol.

More preferably, the span value of the particulate toner composition is 0.8 or less, and the particulate toner composition has a rough surface texture having a surface roughness index of 1.05 or more, which is defined as a ratio of the surface area of the rough surface tissue particles to the surface area of the smooth surface tissue particles. It is desirable to have.

In the present particulate toner composition, the resin is preferably a polyester resin or a styrene copolymer resin, and a styrene and acrylate copolymer and a styrene and butadiene copolymer are particularly preferable as the styrene copolymer.

The present invention also provides a developer composition further comprising carrier particles in the particulate toner composition. Preferably, the carrier particles are selected from the group consisting of ferrite, steel, iron powder and mixtures thereof coated with the surfactant.

In another aspect, the present invention is a resin composition comprising a polymer resin, a processing aid, a colorant, and optionally a charge control agent by pulverizing by heating and shearing action in an organic medium insoluble to the resin to form fine resin particles, I) vaporizing the processing aid and separating and recovering from the organic medium, i) the shape of the particles is spherical, ii) the volume average diameter of the particles is in the range of 1 to 10 μm, i) the span value is 1.0 or less, Iii) a method of printing an image by applying a particulate toner composition, wherein the weight average molecular weight of the resin component is in the range of 3,000 g / mol to 100,000 g / mol.

The present invention will be described in more detail through the following examples. However, since the embodiments are only intended to illustrate the invention, the scope of the present invention should not be construed as limited to the examples.

Example 1

CI Pigment Blue (Heliogen ^™ Blue D7100 available from BASF Corporation, Charlotte, NC) with a color index constitution number 74160 and a negative charge control agent (Bontron ^TM E-88 available from Orient Chemical Corporation) Dispersed in propoxylated bisphenol A polyester resin (Find Tone ^TM 82ES, available from Reichold Chemicals, Incorporated, North Carolina Research Triangle Park) according to the procedure of. In a 2000 ml round flask equipped with an impeller stirrer, 500 g of resin and 150 g of DMF were mixed and then heated to about 150 ° C. When the mixed melt has fluidity, it is maintained for about 1 hour while mixing at 50 rpm. When the solution becomes completely mixed, add 250 g of ISOPAR®L and 250 g of ISOPAR®V, and mix 50 g of Ganex V-220 in a round flask. When the addition is complete, the stirring speed is raised to 400 rpm and maintained for 4 hours. When the mixture forms a milky white dispersion, the dispersion is allowed to cool to room temperature. The treated particles are separated from the reaction mixture by filtration and the filter cake is separated by dispersing in normal hexane to wash the solvent incorporated in the filter cake. The filtered particles are dried under vacuum at 40 ° C. for 16 hours.

Mix 100 parts by weight of Cab-O-Sil® TS-720 (fumed silica, which acts as a fluidity enhancer available from Cabot Corporation, Tuscany, Ill.) And mix in a roll mill for 15 minutes. . Accordingly, the cyan toner No. 1-1 is obtained.

The resulting cyan toner was 95.3 wt% polyester resin and 4.7 wt% C.I. Pigment Blue 15: 3, which had a mean particle size of 0.1 micron as measured by transmission electron microscopy. The volume average particle diameter of the toner prepared by the above invention was 4.7 microns, and the span was 0.6. Examining the toner particles with a scanning microscope revealed that the particles were all spherical and had a rough surface. The roughness index of the particles defined using the BET isothermal curve method was about 2.0.

Example 2

500 ml of polymer, 25 g of pigment, 150 g of dimethyl formamide (commercially available from Aldrich Chemical Company, Milwaukee, WI) and 15 g of charge control agent in a 2000 ml round flask with impeller and condenser Aluminum trihydroxide (commercially available from Aldrich Chemical Company, Milwaukee, Wisconsin). When the contents are stirred uniformly for 1 hour while stirring at a rate of 50 rpm under a full reflux condition of 150 ℃, the fluidity is improved. It can be seen from the transparency of the contents that the contents have a very uniform dispersion and a small size.

A 1: 1 mixture of Isopar-L? And Isopar-V? (Commercially available from Exxon Chemical Company, Houston, Texas) was charged with 500 g of incompatible solvent and 25 g of Ganex V220 (Wayne, NJ) Commercially available) is added to the flask. The subsequent process is the same as in Example 1, from which the cyan toner 1-2 of the present invention is produced.

The resulting cyan toner 1-2 was 92.6% polyester resin and 4.6% C.I. Pigment Blue 15: 3 and 2.7% of aluminum trihydroxide. The size of the cyan toner was 6 microns in average and 0.8 in span. Compared with Example 1, it can be seen that the size of the particles is controlled by the content of the surfactant. When observed using a scanning electron microscope, the particles had a rounded surface with a rough surface. The surface roughness index obtained by the BET experiment was about 1.9.

Example 3

Magenta toner is C.I. Pigment Blue 15: 3 instead of C.I. Pigment Red 81: 3 (Rjodamine YS PMA, available from Magruder Color Company, Elizabeth, NJ) was prepared in the same manner as in Example 1.

The resultant magenta toner was 95.3 wt% polyester resin and 4.7 wt% C.I. It contains Pigment Red 81: 3. The volume average particle diameter of the toner prepared by the above invention was 4.8 microns, and the span was 0.7. Examination of the toner particles with a scanning microscope revealed that the particles were all spherical and had a rough surface. The surface roughness index obtained by the BET experiment was about 1.9.

Example 4

The same process as in Example 1 was repeated except that the yellow toner had a C.I. Pigment Blue 15: 3 instead of C.I. Pigment Yellow 185 (Enceprint 1155, available from BASF Corporation, Charlotte, NC).

The resulting yellow toner was 95.3 wt% polyester resin and 4.7 wt% C.I. Pigment Red 81: 3. The volume average particle diameter of the toner prepared by the above invention was 4.7 microns, and the span was 0.8. The surface roughness index obtained by the BET experiment was about 1.9.

Example 5

25 g of carbon black S160 (Degussa Corporation, Dusseldorf, Germany) and 10 g of negative charge control agent (Bontron ^TM E-88, available from Orient Chemical Corporation) were propoxylated bisphenol A polyester resin (North Carolina Research) Disperse in Find Tone ^TM 82ES available from Reichold Chemicals, Incorporated, Triangle Park. In a 2000 ml round flask equipped with an impeller-type stirrer, 500 g of resin and 150 g of DMF are mixed, and then heated to 150 ° C. If the mixed melt has fluidity, the mixture is kept at 50 rpm for about 1 hour. When the solution becomes completely mixed, add 250 g of ISOPAR? L and 250 g of ISOPAR? V, and mix 50 g of Ganex V-220 in a round flask. When the dosing is complete, increase the stirring speed to 400 rpm and hold for 4 hours. When the mixture forms a milky white dispersion, the dispersion is allowed to cool to room temperature. The treated particles are separated from the reaction mixture by filtration and the filter cake is separated by dispersing in normal hexane to wash the solvent incorporated in the filter cake. The filtered particles are dried under vacuum at 40 ° C. for 16 hours.

Mix 100 parts by weight of Cab-O-Sil? TS-720 (fumed silica, which acts as a fluidity improver available from Cabot Corporation, Tuscola, Illinois) and mix in a roll mill for 15 minutes. . According to the present invention, a black toner is obtained.

The resulting cyan toner contained 95.3 wt% polyester resin and 4.7 wt% carbon black, with an average particle size of 0.1 micron as measured by transmission electron microscopy. The volume average particle diameter of the toner prepared by the above invention was 4.7 microns, and the span was 0.6. Examining the toner particles with a scanning microscope, it was found that the particles were all spherical and had a rough surface. The roughness index of the particles defined using the BET isothermal curve method was about 2.2.

Example 6

CI Pigment Blue (Heliogen ^™ Blue D7100, available from BASF Corporation, Charlotte, NC) with a color index constitution number 74160 and a negative charge control agent (Bontron ^TM E-88, available from Orient Chemical Corporation) Dispersed in propoxylated bisphenol A polyester resin (Find Tone ^TM 82ES, available from Reichold Chemicals, Incorporated, North Carolina Research Triangle Park) according to the procedure of. In a 2000 ml round flask equipped with an impeller stirrer, 500 g of resin and 150 g of acetone are mixed and warmed to about 50 C. When the mixed melt has fluidity, it is maintained for about 1 hour while mixing at 50 rpm. When the solution becomes completely mixed, add 250 g of ISOPAR? L and 250 g of ISOPAR? V, and mix 50 g of Ganex V-220 in a round flask. When the dosing is complete, increase the stirring speed to 400 rpm and hold for 4 hours. When the mixture forms a milky white dispersion, the dispersion is warmed to about 70 ° C. to remove acetone. At this time, the temperature of the cooling tube is maintained at about 5 ℃. The treated particles are separated from the reaction mixture by filtration and the filter cake is separated by dispersing in normal hexane to wash the solvent incorporated in the filter cake. The filtered particles are dried under vacuum at 40 ° C. for 16 hours. Mix 100 parts by weight of Cab-O-Sil? TS-720 (fumed silica, which acts as a fluidity improver available from Cabot Corporation, Tuscola, Illinois) and mix in a roll mill for 15 minutes. . According to the present invention, cyan toner No. 2-1 is obtained.

The resulting cyan toner was 93.2 wt% polyester resin and 4.9 wt% C.I. Pigment Blue 15: 3, and 1.9 wt% negative charge control agent, with an average particle size of 0.1 micron as measured by transmission electron microscopy. The volume average particle diameter of the toner prepared by the above invention was 4.7 microns, and the span was 0.8. Examining the toner particles with a scanning microscope, it was found that the particles were all spherical and had a rough surface. The roughness index of the particles defined using the BET isothermal curve method was about 2.0.

Example 7

Prepare particles as in Example 1, but do not add DMF as a processing aid. The average size of the resulting particles was 5.1 microns and the span was very wide at 2.0. This demonstrates the usefulness of the present invention. Also, the shape of the particles observed by the scanning electron microscope was found to be smooth spherical shape, the surface roughness index was about 1.

Example 8

50 g and 2.5 g of C.I. styrene copolymer (commercially available from Aldrich Chemical Company, Milwaukee, WI) in a 500 ml round flask equipped with an impeller and a distillation tube. Pigment Blue 15: 3 is mixed and added, and 60 g of tetrahydrofuran (commercially available from Aldrich Chemical Company, Milwaukee, Wis.) Is added and stirred with the mixture at room temperature. When the flask is heated at about 50 degrees under full reflux conditions and stirred for 1 hour at a speed of 50 rpm, it has sufficient fluidity.

Once the mixture has sufficient fluidity, 100 g of water as an incompatible solvent and 2.5 g of sodium dodecyl sulfonate (commercially available from Aldrich Chemical Company, Milwaukee, Wis.) As a surfactant are added. When the dosing is completed and uniformly dispersed, the stirring speed is increased to 200 rpm, the temperature is maintained at 50 ° C. under the conversion flow conditions, and nitrogen is supplied to the flask at a flow rate of about 10 cc / min. After 2 hours, the tetrahydrofuran, a processing aid, is obtained by condensation in the cooling tube while operating under partial reflux conditions. The temperature of the flask is raised to 80 ° C to completely remove the tetrahydrofuran from the mixture. The temperature is cooled to room temperature when no steam of tetrahydrofuran is generated in the injected nitrogen. The slurry is left in the reactor in which the styreneacryl copolymer is mixed with the pigment. The slurry is washed three times with distilled water and dried at 50 ° C. for 10 hours.

Cyan toner is obtained by mixing 100 parts by weight of toner and 1 part by weight of Cab-O-Sil TG-308F (fumigated silica as a fluidity improver available from Cabot Corporation, Tuscola, Ill.) For 15 minutes using a roll mill. Lose.

The volume average particle size of the resultant toner using styrene acryl as a base resin was 6.8 microns and the span was 0.7. The surface of the particles observed using the scanning electron microscope was rough, and the roughness index of the particles obtained from the BET isothermal curve was 2.2.

Example 9

Another cyan toner based on styrene acryl was prepared in the same manner as in Example 8, but the content of sodium dodecyl sulfonate in Example 8 was changed from 2.5 g to 4 g. The volume average particle size of the resulting cyan toner was 4.8 microns and the span value was 0.9. The surface observed using the scanning electron microscope was rough, and the roughness index measured from the BET isothermal curve was 2.0.

Example 10

Magenta toner based on styrene acryl was prepared in the same manner as in Example 8, except that the content of sodium dodecyl sulfonate in Example 8 was changed from 2.5 g to 4 g, and the pigment was replaced with CI Pigment Red 81: 3. It was. The volume average particle size of the resulting magenta toner was 4.8 microns and the span value was 0.9. The surface observed using the scanning electron microscope was rough, and the roughness index measured from the BET isothermal curve was 2.0.

Example 11

A yellow toner based on styrene acryl was prepared in the same manner as in Example 8, except that the content of sodium dodecyl sulfonate in Example 8 was changed from 2.5 g to 4 g, and the pigment was replaced with C. I. Pigment Yellow 185. The volume average particle size of the produced yellow toner was 5.1 microns, and the span value was 0.8. The surface observed using the scanning electron microscope was rough, and the roughness index measured from the BET isothermal curve was 2.1.

Example 12 Binary Toner Printing Test

The toner composition in Example 1 was used for injection into a color copier (Canon CLC-900 commercially available from Canon Corporation, Tokyo, Japan) and then tested. The light density of the front cyan image was 1.55 and the thickness of the printed toner layer was 20 microns. After copying 40,000 copies, it was confirmed that the light density of the output was good as 1.51.

The toner of the present invention is a spherical toner having a small particle diameter by producing particles of a polymer resin including colorants, processing aids and other additives using strong shear conditions in a dispersion medium containing a surfactant. The particles can be formed to produce a high resolution color toner that combines excellent properties for use in an electrophotographic imaging system.

Advantageous Effects of the Invention The present invention can produce particulate toner at lower temperatures by using a processing aid during the process, and not only high molecular weight resins can be used but also the particulate toner produced thereby has desirable charging properties due to its rough surface properties. There is this.

Claims (43)

(a) preparing a first resin composition comprising a polymer resin, a processing aid, a colorant, and optionally a charge control agent, (b) dispersing said first resin composition in an organic medium comprising an organic solvent and a surfactant and insoluble in said resin, (c) pulverizing the first resin composition by heating and shearing in the organic medium to form resin fine particles, (d) heating the pulverized resin fine particles to vaporize the processing aid to produce a fine particle toner, (e) separating and recovering the particulate toner from the organic medium Including; Wherein the pulverized toner fine particles are spherical, the volume average diameter of the particles is in the range of 1 to 10 μm, and a span value is 1.0 or less. delete delete The method of claim 1, A volume average diameter of the toner fine particles is in the range of 3 to 8 µm. The method of claim 1, The span value is 0.8 or less, wherein the fine particle toner composition for electrostatic latent image development is produced. The method of claim 1, Wherein the toner fine particles have a rough surface texture of 1.05 or greater surface roughness index, and the surface roughness index is defined as a ratio of the surface area of the rough surface tissue particles to the surface area of the smooth surface tissue particles. A method for producing a particulate toner composition for electrostatic latent image development. delete The method of claim 1, The resin is selected from polyester resins or styrene-based copolymer resins, The resin is an amorphous resin, the glass transition temperature of the resin component is in the range of 40 to 90 ℃, the weight average molecular weight is in the range of 3,000 g / mol to 100,000 g / mol to prepare a particulate toner composition for electrostatic latent image development How to. delete delete The method of claim 1, A process for producing a particulate toner composition for electrostatic latent image development, characterized in that the boiling point of the processing aid is 200 ° C. or less and is an organic solvent that can be dissolved in the resin at a concentration of 1% by weight or more. The method of claim 11, The processing aid is selected from the group consisting of acetone, tetrahydrofuran, acetonitrile, methyl ethyl ketone, 3-pentanone, chlorobenzene, N, N-dimethylformamide, cyclohexanone and dimethyl sulfoxide A method for producing a particulate toner composition for electrostatic latent image development. The method of claim 11, A process for producing a particulate toner composition for electrostatic latent image development, wherein said processing aid has no compatibility with said organic solvent used in dispersing said first resin composition. The method of claim 1, And wherein said processing aid is mixed with said resin in an amount of from 1 to 200% by weight of said resin component. The method of claim 14, A process for producing a particulate toner composition for electrostatic latent image development, wherein said processing aid is mixed with said resin at 5 to 100% by weight of said resin component. delete delete delete The method of claim 1, Wherein the step of dispersing the first resin composition in the organic medium is performed by introducing the first resin composition while stirring the organic medium at a temperature above the flow temperature of the first resin composition. A method of producing a particulate toner composition for latent image development. The method of claim 1, Wherein said step of dispersing said first resin composition in said organic medium is carried out by introducing said organic medium into said container while stirring a container containing a melt of said first resin composition. A method for producing a developing particulate toner composition. The method of claim 1, And a solubility index of the organic solvent in the organic medium differs from the solubility index of the resin by at least one. The method of claim 21, A method for producing a particulate toner composition for electrostatic latent image development, characterized in that the solubility index of the organic solvent in the organic medium differs from the solubility index of the resin by two or more. The method of claim 1, A method of producing a particulate toner composition for electrostatic latent image development, characterized in that the organic medium comprises a paraffin solvent. The method of claim 1, A method for producing a particulate toner composition for electrostatic latent image development, wherein the organic medium comprises polyethylene glycol. delete delete The method of claim 1, And said organic medium comprises an organic solvent and a surfactant, and the surfactant is present at 0.2 to 15% by weight of the amount of the organic solvent in which the surfactant is present. The method of claim 27, A method for producing a particulate toner composition for electrostatic latent image development, wherein the surfactant is present in an amount of 1 to 10% by weight of the amount of the organic solvent present. The method of claim 1, During the pulverizing the first resin composition, the first resin composition is present in the particulate toner composition for electrostatic latent image development, characterized in that present in 10 to 70% by weight of the combined weight of the first resin composition and the organic medium. How to manufacture. The method of claim 29, During the pulverizing the first resin composition, the first resin composition is present in the electrostatic latent image developing particulate toner composition, characterized in that 20 to 50% by weight of the combined weight of the first resin composition and the organic medium. How to manufacture. The method of claim 1, The step of pulverizing the first resin composition is prepared by dispersing and stirring the first resin composition in the organic medium in the temperature range of 30 to 200 ℃ to produce a particulate toner composition for electrostatic latent image development Way. The method of claim 1, Removing the processing aid from the pulverized first resin composition disperses the pulverized first resin composition in the organic medium under heated and stirred conditions close to the boiling point of the processing aid and outflows from the dispersion A process for producing a particulate toner composition for electrostatic latent image development, characterized in that it is carried out in such a manner as to maintain said dispersed state until steam does not contain said processing aid component. The method of claim 1, Separating the pulverized particulate resin is a method for producing a particulate toner composition for electrostatic latent image development, characterized in that the filtration process. The method of claim 1, A method of producing a particulate toner composition for electrostatic latent image development, further comprising applying a fluidity improver to the pulverized particulate toner. The method of claim 34, wherein A method for producing a particulate toner composition for electrostatic latent image development, characterized in that the fluidity improver comprises fumed silica. The method of claim 1, Equipment for manufacturing the first resin composition, dispersing the first resin composition, pulverizing the first resin composition to form fine particles, and vaporizing the processing aid to produce particulate toner A process for producing a particulate toner composition for electrostatic latent image development, characterized in that it is carried out as a set of separate separate steps made in the process. The method of claim 1, Preparing the first resin composition, dispersing the first resin composition, pulverizing the first resin composition to form fine particles, and vaporizing the processing aid to produce particulate toner A process for producing a particulate toner composition for electrostatic latent image development, characterized in that it is carried out as a set of steps made continuously in a facility. The resin composition comprising a polymer resin, a processing aid, a colorant, and optionally a charge control agent is pulverized by heating and shearing in an organic medium insoluble to the resin to form fine resin particles, and then the processing aid is vaporized and the organic medium is vaporized. A particulate toner composition prepared by separating and recovering from i) the shape of the particles is spherical, ii) the volume average diameter of the particles is in the range of 1 to 10 μm, i) the span value is 1.0 or less, and i) the weight average molecular weight of the resin component is from 3,000 g / mol to Particulate toner composition, characterized in that the range of 100,000g / mol. The method of claim 38, The toner fine particles of the particulate toner composition have a rough surface texture of surface roughness index of 1.05 or more, and the surface roughness index is defined as a relative ratio of the surface area of the rough surface tissue particles to the surface area of the smooth surface tissue particles. Particulate toner composition. The method of claim 38, The fine particle toner composition, wherein the resin is a polyester resin. The method of claim 38, The particulate toner composition, wherein the resin is a styrene copolymer resin. 39. A developer composition comprising the particulate toner composition according to claim 38 and further comprising carrier particles, wherein the carrier particles are selected from the group consisting of ferrite, steel and iron powder coated with a surfactant. A developer composition, characterized by the above-mentioned. The resin composition comprising a polymer resin, a processing aid, a colorant, and optionally a charge control agent is pulverized by heating and shearing in an organic medium insoluble to the resin to form fine resin particles, and then the processing aid is vaporized and the organic medium is vaporized. A particulate toner composition prepared by separating and recovering from i) the shape of the particles is spherical, ii) the volume average diameter of the particles is in the range of 1 to 10 μm, i) the span value is 1.0 or less, and i) the weight average molecular weight of the resin component is from 3,000 g / mol to A method of printing an image by applying a particulate toner composition, characterized in that the range of 100,000 g / mol.