KR100321085B1 - Incidental electrophotographic toner, its manufacturing method, electrostatic latent imager and image forming method. - Google Patents

Abstract

To improve the dispersibility of the colorant and release agent in the toner to significantly improve the drawbacks of the prior art, to provide a toner having excellent offset properties, charging properties, storage properties, good color development and OHP permeability in response to the demand for high performance.

As an incident electrophotographic toner containing a binder resin and a colorant, the colorant is dispersed by a polymer dispersant having an acid value of 1 mg KOH / g or more and 27 mg KOH / g and an amine value of 1 or more and 100 or less.

Description

Conductive electrophotographic toner, manufacturing method thereof, electrostatic latent image developer, and image forming method.

The present invention relates to an electrophotographic toner used in an electrophotographic method, a manufacturing method thereof, and an electrostatic latent image developer and an image forming method using the electrophotographic toner.

Background Art Conventionally, a kneading pulverization method is known as a manufacturing method of toners used in electrophotography, and it has been common to pulverize a toner compounding component after kneading to obtain a toner having a desired particle size. At present, toners produced by kneading and pulverization are widely used, but as the required performance of users increases, better toners are required.

At present, the performance that is more strongly desired for electrophotography is cleanerless (which does not generate waste toner) which is greatly related to resource saving, etc., miniaturization of machines that have increased in demand with the development of personal computers, High speed and high quality. Especially in the phenomenon where the display of the computer is almost fixed in color, the demand for these performances in the color output is very high.

However, the toner obtained by the kneading pulverization method is irregular in shape, which causes a problem of low fluidity of the toner, a large contact area with the surface of the latent electrostatic image bearing member, and deterioration in transferability. In the kneading and pulverizing method, since the colorant added to the toner is exposed to the surface of the obtained toner, the charging of the toner surface becomes uneven and widens the charge distribution of the toner, resulting in a problem of deterioration in developing characteristics. Because of such a problem, the kneading pulverization method cannot fully meet the demand for high performance.

Therefore, in order to be able to respond to the demand for high performance, various manufacturing methods have been proposed. For example, Japanese Patent Application Laid-Open Nos. 60-222868, 61-114247, and 59-162562 disclose a toner having a capsule structure and a manufacturing method thereof. In this manufacturing method, the toner can be spherical and a toner excellent in fluidity and transferability can be obtained. In addition, since the coloring agent or the like is not exposed to the toner surface, the obtained toner also has excellent uniformity of charging. However, since the rigid shell completely covers the toner surface, the roll type passion bonding method, which has become the mainstream, is inferior in fixability, making it difficult to speed up and downsize.

Also, Japanese Unexamined Patent Publication No. 36-10234 proposes a suspension polymerization toner having a pseudo-capsule structure and a manufacturing method thereof. In this suspension polymerization method, the toner can be spherical, and a toner excellent in fluidity and transferability can be obtained. In addition, since the colorant and the like are not easily exposed to the toner surface, the obtained toner also has excellent uniformity of charging.

However, since the polymerization of the resin is performed simultaneously with the production of the toner, the material commonly used for the toner cannot be used in many cases. Moreover, even if it can superpose | polymerize using a conventional material, particle size cannot fully be controlled because of the influence of additives, such as resin and a coloring agent. Therefore, this method has a problem that the degree of freedom of material selection is reduced. Particularly problematic is that polyester resins which have exhibited excellent fixing performance and color aptitude in the conventional kneading pulverization method cannot be basically used, and therefore, they cannot sufficiently cope with miniaturization, high speed, and colorization.

In order to solve such a problem, Japanese Unexamined Patent Publication Nos. 5-127422, 7-152202, 7-168395, and 7-271099 disclose a method for producing a toner by a melt suspension method. It is proposed. The dissolution suspension method is a method of suspending and granulating an oil layer obtained by dissolving or dispersing a toner component in an organic solvent in an aqueous phase. Since it does not include a polymerization step, a wide range of materials can be used, and thus a polyester resin or colorant can be used. Easy to visualize and toner. For this reason, a toner excellent in fluidity and excellent in transferability can be obtained, and a cleaner can be formed. In addition, since there is no charge nonuniformity by exposure of a coloring agent, it is excellent also in fixing property and color aptitude is acquired, and it is expected that it can respond to miniaturization, high speed, and colorization.

However, even in the solution suspension method which hardly exposes the colorant component on the surface of the toner, since the colorant tends to aggregate, it is difficult to uniformly add and disperse the colorant in the toner, and the method of injecting the colorant varies depending on the toner. There is also a problem in that nonuniformity of charging occurs, and the stability of long-term use decreases. In the case of color output, slight deterioration of developability and transferability becomes a problem of deterioration of color balance and gradation. In addition, the colorant in the toner is generally incompatible with the resin, and thus diffusely reflects the transmitted light at its interface, thereby impairing the transmittance of OHP and the like. Therefore, when dispersion of a coloring agent is bad, there also exists a problem that the permeability in OHP deteriorates.

In particular, the color output machine does not require an oil supply unit of the fixing unit, and an oilless toner containing a release agent instead of oil in the toner is common sense, but since the release agent cannot be atomized as much as the colorant, it is more uniform. It is difficult to add and disperse, and when the release agent is poorly dispersed, there is also a problem of impairing chargeability, developability, storageability, and OHP permeability.

As a method of dispersing the colorant, in the kneading milling method, a method of using a flashing pigment is generally used, but in the dissolution suspension method, even if a flashing pigment is used, the flashed resin dissolves and does not exert its effect. , Dispersibility cannot be improved. In addition, in the kneading and pulverization method, high shear force can be easily applied to the dispersion of the release agent. However, in the solution suspension method, a shear force sufficient to sufficiently disperse the release agent cannot be applied.

Japanese Patent Application Laid-Open No. 5-119529 proposes similarly to the use of a graft resin as a binder resin in order to improve the dispersibility of a colorant in the emulsion dispersion method, which is a manufacturing method of a toner using a solvent. This method can surely improve the dispersibility of the colorant, but since the graft ratio of the binder resin needs to be considerably increased, the binder resin tends to be deteriorated, and in particular, the fixing characteristics of the color toner and the image quality are problematic. It is not preferable because it may be.

As described above, an electrophotographic toner capable of sufficiently meeting the demand for high performance has not yet been obtained.

Accordingly, an object of the present invention is to improve the dispersibility of a colorant and a releasing agent in a toner, thereby greatly improving the drawbacks of the prior art, and having excellent offset, charging and storage properties, and good color development and OHP permeability to meet the demand for high performance. To provide toner.

1 is a transmission electron microscope photograph showing the particle structure of the toner of Example 1;

Fig. 2 is a transmission electron microscope photograph showing the particle structure of the toner of Comparative Example 1;

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining, it discovered that the dispersibility and dispersion stability of a coloring agent improve by adding the polymer dispersing agent which has a predetermined acid value and an amine value, and came to complete this invention.

In other words, the electrophotographic toner of the present invention contains a binder resin and a colorant, wherein the colorant is dispersed in a polymer dispersant having an acid value of 1 mg KOH / g or more and 27 mg KOH / g and an amine value of 1 or more and 100 or less. It is an electrophotographic toner.

The addition amount of the coloring agent is preferably 1 part by weight or more and 50 parts by weight or less with respect to 100 parts by weight of the binder resin, and the polymer dispersant is preferably contained in the ratio of 0.1% by weight to 10% by weight in the toner, and in the case of the polycaprolactone derivative It is preferable to contain at 1 weight part or more and 50 weight part or less with respect to 100 weight part of coloring agents.

It is preferable that a polymer dispersing agent has compatibility with a binder resin, A polycaprolactone derivative is more preferable, A polycaprolactone derivative whose weight average molecular weight is 2000 or more and 10,000 or less is especially preferable.

It is preferable that the electrophotographic toner of the present invention further contains a releasing agent, and the content of the releasing agent is preferably 1 part by weight or more and 50 parts by weight or less with respect to 100 parts by weight of the electrophotographic toner, and the melting point of the release agent is 120 ° C. or less. desirable. In addition, the binder resin of the electrophotographic toner is preferably a polyester resin.

As the method for producing the electrophotographic toner of the present invention, a binder resin and a colorant dispersed by an acid value of 1 mg KOH / g or more and 27 mg KOH / g or less and an amine value of 1 or more and 100 or less are dissolved or dissolved in an organic solvent. Particularly preferred is a method of dispersing to adjust the oil phase component, and dispersing the oil phase component in an aqueous medium to granulate it. That is, it is preferable to produce a toner using the polymer dispersant of the present invention by a so-called solution suspension method.

In addition, by dispersing or dispersing the colorant obtained by dispersing with a polymer dispersant having an acid value of 1 mg KOH / g or more and 27 mg KOH / g or less and an amine value of 1 or more and 100 or less in a polymerizable monomer to adjust the oil phase component, and the oil phase component is an aqueous medium. It can also manufacture by the method of disperse | distributing in the inside, polymerizing, and particle | grains. That is, the toner may be produced using the polymer dispersant of the present invention by the so-called suspension polymerization method.

In these methods, it is preferable to disperse | distribute the colorant dispersion liquid which disperse | distributed the coloring agent in the organic solvent previously with the polymer dispersing agent in an organic solvent with a binder resin or a polymerizable monomer, and to make it an oil phase component. In the case of using the suspension polymerization method, the colorant is preferably dispersed in the polymerizable monomer with a polymer dispersant to form an oil phase component.

In addition, the mixing ratio of the colorant and the organic solvent is preferably in the range of 5:95 to 50:50, and it is preferable that the aqueous medium contains an inorganic dispersant and / or a dispersion stabilizer. At this time, it is preferable that content of an inorganic dispersing agent is 0.1 weight part or more and 20 weight part or less with respect to 100 weight part of mother liquids.

The polymer dispersing agent used for this invention can raise affinity of a dispersing agent, a binder resin, and a coloring agent by setting an acid value and an amine value to a fixed range, and can balance the polar part and nonpolar part suitably. Accordingly, in the case where the polymer dispersant used in the present invention is added, the dispersibility and dispersion stability of the colorant and the fluidity of the toner are exhibited while exhibiting high dispersibility to the colorant, the resin and the solvent while suppressing the influence on the chargeability of the toner. It is estimated to improve.

That is, in the electrophotographic toner of the present invention, by adding a polymer dispersant to the dispersion of the colorant, the dispersibility of the colorant is improved, the color development of the toner and the light transmittance of the OHP are improved, and the colorant is stable for a long time during manufacture. Since it can disperse | distribute easily, the efficiency of particle manufacture becomes high.

In particular, the toner of the present invention is prepared by using the polymer dispersant of the present invention by a so-called solution suspension method, whereby the colorant fine particles are uniformly dispersed in the toner particles due to the difference in affinity between the colorant and the oily component and the colorant and the aqueous medium. The exposure amount of the colorant on the surface of the toner is reduced. Moreover, the choice of resin and a coloring agent becomes wider, and other additives, such as a wax, can also be added. In addition, shape control can be performed, and spherical particles can be easily formed.

Therefore, the toner obtained by this manufacturing method is excellent in chargeability, fluidity, stability and transferability. That is, by applying the toner of the present invention to an electrophotographic developer, it is possible to form an image with good image quality and excellent light transmittance in OHP.

In addition, polycaprolactone-based resins are biodegradable resins, so there is no environmental pollution.

[Embodiment of the Invention]

Hereinafter, the present invention will be described in more detail.

As the binder resin of the present invention, a known fixing resin can be used.

Specific examples include polymers of acrylic esters such as polymethyl acrylate, polyethyl acrylate, polybutyl acrylate, poly 2-ethylhexyl acrylate and polylauryl acrylate; Polymers of methacrylic acid esters such as polymethyl methacrylate, polybutyl methacrylate, polyhexyl methacrylate, poly2-ethylhexyl methacrylate and polylauryl methacrylate; Copolymers of acrylic esters with methacrylic esters; Copolymers of styrene monomers with acrylic or methacrylic esters; Ethylene-based polymers and copolymers thereof such as polyvinyl acetate, polyvinyl propionate, polyvinyl butyrate, polyethylene and polypropylene; polystyrene; Styrene-type copolymers, such as a styrene butadiene copolymer, a styrene isoprene copolymer, and a styrene maleic acid copolymer; Polyester obtained by condensation polymerization of an alcohol component and a carboxylic acid component; Polyvinyl ether; Polyvinyl ketones; Polyester; Polyamides; Polyurethane; Rubbers; Epoxy resins; Polyvinyl butylal; rosin; Modified rosin; Terpene resins; A phenol resin etc. can be used individually or in mixture.

Among them, copolymers of polyester, polystyrene, styrene-based monomers with acrylic esters or methacrylic acid esters are preferable in terms of electrophotographic properties such as fixing strength and chargeability, and color developing properties as color toners. Ester is particularly preferred.

As an alcohol component of the polyester obtained by condensation polymerization of an alcohol component and a carboxylic acid component, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, cyclohexanedimethanol, Divalent or more alcohols and glycol derivatives such as silylene glycol, dipropylene glycol, polypropylene glycol, bisphenol A, hydrogenated bisphenol A, bisphenol A ethylene oxide, bisphenol A propylene oxide, sorbitol, glycerin, and the like, and the carboxylic acid component Divalent or higher carboxylic acids such as maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, adipic acid, trimellitic acid, pyromellitic acid, cyclopentanedicarboxylic acid, succinic anhydride, trimellitic anhydride, maleic anhydride and dodecenyl anhydrous succinic acid Carboxylic acid derivatives or anhydrous carboxyl And acid. In addition, an alcohol component and a carboxylic acid component can be used in combination of 2 or more types, respectively.

The binder resin of the present invention preferably has a weight average molecular weight in the range of 5000 to 10,000. If it is less than 5000, storage stability will fall easily, and if it exceeds 10000, the solubility to a solvent will fall easily. Moreover, it is preferable that glass transition point (Tg) is 50-150 degreeC. If it is less than 50 ° C, an image offset is likely to occur, and if it exceeds 150 ° C, fixation is likely to be insufficient.

The compounding quantity of the binder resin of this invention is 50 weight part or more and 99 weight part or less with respect to 100 weight part of toners normally.

As a coloring agent of this invention, a well-known organic or inorganic pigment can be used. Specific examples of the colorant that can be used include inorganic pigments such as carbon black such as furnace black, channel black, acetylene black, thermal black, bengala, blue-green, titanium oxide and the like; Azo dyes such as fast yellow, disazo yellow, pyrazolone red, chelate red, brilliant carmine, para brown; Phthalocyanine pigments such as copper phthalocyanine and metal-free phthalocyanine; And condensed polycyclic pigments such as flavantron yellow, dibromoanthrone orange, perriren red, quinacridone red, and dioxazine biolet.

It is preferable that it is 1 weight part or more and 50 weight part or less with respect to 100 weight part of binder resins, and, as for the addition amount of a coloring agent, it is more preferable that they are 2 weight part or more and 20 weight part or less. When it is less than 1 weight part, coloring power will fall easily, and when it exceeds 50 weight part, fixability and charging property will fall easily.

In this invention, a coloring agent is disperse | distributed and used by the polymer dispersing agent whose acid value is 1 mg KOH / g or more and 27 mg KOH / g or less, and whose amine value is 1 or more and 100 or less. More preferred are polymer dispersants having an acid value of 20 mg KOH / g and an amine number of 35 to 100.

When the acid value exceeds 27 mg KOH / g, the chargeability under high humidity decreases, and the pigment dispersibility is insufficient. When the acid value is less than 1 mg KOH / g, the affinity with the resin decreases and the pigment dispersibility is insufficient. It may become. In addition, the pigment dispersibility becomes insufficient even when the amine number is less than 1 and when the amine value is more than 100.

In addition, an acid value can be measured by the method of JISK0070, and an amine value can be measured by the method of JIS K7237.

In addition, the polymer dispersant preferably has high compatibility with the binder resin in terms of pigment dispersibility, and polycaprolactone derivatives such as polycaprolactone modified with a polyester resin, particularly a silane coupling agent having an amino group or a diisocyanate, desirable.

Specific examples of the polymer dispersant having the above requirements include "EFK47", "EFKA4009", "EFKA4010" (modified polyurethane: manufactured by EFKA Chemical Co., Ltd.), "Ajispa-PB711", "Ajispa-PN711" (manufactured by Ajinomoto Co., Ltd.), "Disparlon DA-703-50", "Disparlon DA-705", "Disparlon DA-725" which are polyester, and "Disparlon DA-400N" (made by Kusumoto Kasei) which are polyamides are mentioned.

It is preferable to mix | blend a polymer dispersing agent in the ratio of 0.1 to 10 weight% in a toner. When the amount is less than 0.1% by weight, the pigment dispersibility is insufficient, and when the content is 10% by weight, the chargeability under high humidity may decrease.

The weight average molecular weight of the polymer dispersant is preferably at least 2000, more preferably at least 3000, and more preferably at least 3000 in terms of pigment dispersibility in terms of the molecular weight of the maximum value of the main peak of the styrene equivalent weight by gel permeation chromatograpry.

Especially in the case of a polycaprolactone derivative, about 500-100000 are preferable and 2000-10000 are more preferable. When the molecular weight is less than 500, the polarity is high and the dispersibility of the colorant is easily lowered. When the molecular weight is more than 100000, the affinity with the solvent is increased and the dispersibility of the colorant is likely to be lowered.

The polycaprolactone derivative used in the present invention is-(O (CH ₂ ) ₅ CO) _n -,-(O (CH ₂ ) ₄ CHCH ₃ CO) _n -,-(O (CH ₂ ) CHCH ₃ (CH ₂ ) ₂ CO) _n -,-(O (CR ₂ ) ₅ CO) _n -refers to a high molecular compound having a structure of can be obtained by ring-opening polymerization of ε-caprolactone. The derivatives also include block copolymers or graft copolymers of? -Caprolactone and other monomers.

As other monomers, ε-caprolactam, ethylene, propylene, isoprene, butadiene, vinyl chloride, vinyl acetate, urethane, acrylic esters, methacrylic acid esters, styrene, acrylonitrile, vinylethyl ether, and derivatives thereof can be used. have.

It is preferable that they are 1 weight part or more and 50 weight part or less with respect to 100 weight part of coloring agents, and, as for the addition amount of a polycaprolactone derivative, it is more preferable that they are 5 weight part or more and 30 weight part or less. It is because when it is less than 1 weight part, dispersibility will fall, and when it exceeds 50 weight part, charging property will fall easily.

These polymer dispersants may be used alone or in combination with other dispersants. As the other dispersant, a polyester dispersant, a polymer of acrylic acid, methacrylic acid and / or esters thereof, a derivative of a colorant, and the like can be used.

In the present invention, by dividing the resin component into a binder resin and a dispersant polymer, most of the dispersant polymer is adsorbed to the pigment particles, and since the amount of the dispersant polymer having an amine number that tends to be positively charged decreases, in particular, In the electrically conductive toner, incidental conductivity is not impaired.

As a solvent of the dispersion liquid of the coloring agent in this invention, a general organic solvent is used. For example, hydrocarbons such as toluene, xylene, nucleic acids, halogenated hydrocarbons such as methylene chloride, chloroform, dichloroethane, alcohols such as methanol and ethanol, ethers such as tetrahydrofuran, methyl acetate, ethyl acetate, butyl acetate and the like Ketones, such as ester, acetone, methyl ethyl ketone, and cyclohexanone, are mentioned, You may use these independently or a some mixed solvent.

It is preferable that the compounding ratio of the colorant and the organic solvent in the dispersion of the colorant is in the range of 5:95 to 50:50. If the blending ratio of the colorant is less than this, the amount of dispersion is large at the time of toner production, and the efficiency of toner production is easily lowered. If the blending ratio of the colorant is more than this, dispersion of the pigment tends to be insufficient.

The coloring agent may use the dispersion liquid of the coloring agent obtained by disperse | distributing only a coloring agent only in an organic solvent previously, and may be disperse | distributed directly in an organic solvent with a binder resin. Moreover, even when disperse | distributing a coloring agent previously, since a suitable shear force is applied at the time of pigment dispersion, you may add a binder resin and adjust a viscosity.

Dispersion of the colorant may be performed by mixing the colorant and the polymer dispersant in a solvent, and using a media disperser such as a ball mill, a sand mill, an attritor, a coball mill, a roll mill such as a three-roll, and a nanomizer. And a general dispersing device such as a cavitation mill, a colloid mill, an ultrasonic homogenizer, or the like.

It is preferable that the colorant particle diameter in the dispersion liquid after colorant dispersion is 1 micrometer or less. When larger than 1 µm, the particle size of the colorant is large when the toner is formed, so that the image quality is easily lowered, and in particular, the light transmittance of the OHP tends to be lowered. In addition, the particle size of a coloring agent can be calculated | required with the laser diffraction / scattering particle size analyzer "LA-700" (made by Horiba Seisakusho).

In order to enhance the interaction between the colorant and the polymer dispersant and to disperse and stabilize the colorant, it is desirable to add a colorant derivative having a high affinity for the colorant, or to perform a surface treatment of the colorant.

Specific examples of the colorant derivatives include dimethylaminoethylquinacridone, dihydroquinacridone, carboxylic acid derivatives of anthraquinones, sulfonic acid derivatives of anthraquinones, "Solperse 5000", "Solperse 12000" and "Solperse 22000" (Geneca) And "EFKA-745", "LP 6750" (made by EFKA Chemical Co., Ltd.), etc. are mentioned.

As the surface treatment agent of the colorant, natural rosin such as gum rosin, wood rosin, toll rosin, abietinic acid derivatives such as abietinic acid, levopimaric acid, dextromemaric acid, And metal salts such as calcium salts, sodium salts, potassium salts and magnesium salts, rosin maleic acid resins, and rosin phenolic acid resins. In order to improve affinity with a pigment dispersant especially, use of an acidic surface treating agent is preferable.

0.1-100 weight% is preferable with respect to a coloring agent, and, as for the addition amount of a coloring agent derivative and the surface treating agent of a coloring agent, 0.1-10 weight% is more preferable.

In the present invention, as other components, a mold release agent may be added at the time of particle production in order to have mold release property at the time of fixing, and to enable oil reduction or oil-free of a fixing roll. There is no problem in the dispersibility of a coloring agent even if a mold release agent is added at the time of particle manufacture.

Silicone oil and wax can be used as a mold release agent which can be used for this invention, Petroleum wax, such as paraffin wax, paraffin wax, microcrystal wax, mineral wax, such as montan wax, carnauba wax, etc. And animal waxes, polyolefin waxes, polyolefin waxes, synthetic waxes such as Fisher-Tropsch waxes or ester waxes, ether waxes, and the like.

The melting point of the releasing agent is not particularly limited, but is preferably 150 ° C. or lower from the viewpoint of offset resistance, and more preferably 40 ° C. to 150 ° C., and even more preferably 50 ° C. to 120 ° C. from the viewpoint of operability, ease of manufacture, and storage properties. Do. However, at room temperature, a liquid release agent, that is, a release agent having a melting point of less than 40 ° C may also be used.

In addition, it is desired to disperse the release agent smaller in advance, and it is desired to disperse to an average of 1 μm or less. However, when preparing toner particles, the release agent fine particle powder may be added as it is or may be dispersed in a solvent. As the wax dispersing method for reducing the wax particle size, a method of dissolving the wax in an organic solvent, followed by cooling precipitation to finely disperse it, or a method of evaporating the wax in the gas phase to make it fine particles. The organic solvent used in the former case is used the same as the solvent used when producing the particles alone or mixed, but does not necessarily have to be the same as the solvent used when producing the particles.

The amount of the solvent is preferably 0.1 to 20 parts by weight of the solvent with respect to 1 part by weight of the wax. The wax can be dissolved by heating, pressurization or the like. In the method of evaporating the wax in the gas phase to make fine particles, inert gas of helium, argon and nitrogen is used as the gas phase, and the wax is heated to a temperature of 100 to 400 ° C, evaporated under reduced pressure of 1.33 to 1333 Pa, and the wax is evaporated. The fine particles can be attached to a cooled substrate and then separated or dispersed in a solvent to form the fine particles. When producing toner particles, the wax fine particle powder may be added as it is, or may be dispersed in a solvent. In this method, the oil content of narrow molecular weight distribution can also be isolate | separated by adjusting temperature and pressure reduction degree.

It is preferable that content of a mold release agent is 1 weight part or more and 50 weight parts or less with respect to 100 weight part of electrostatic latent image developing toners. If less than 1 part by weight, releasability tends to be insufficient, and if more than 50 parts by weight, the toner surface is easily exposed, so that chargeability and storage stability tend to decrease.

As other additives, fine particles such as metal oxides such as silicon oxide, titanium oxide and aluminum oxide, metal salts, ceramics, resins and carbon black may be added to impart fluidity and the like.

As a method of adding fine particles, the toner may be dried and adhered to the surface of the toner dry using a mixer such as a V blender, Henschel mixer, or the like, and the fine particles are dispersed in water or an aqueous liquid such as water / alcohol, and then slurry toner And an external additive may be attached to the surface of the toner by drying. Moreover, you may dry, spraying a slurry to dry powder.

As a charge control agent which can be used for this invention, what is conventionally used as a developer can be used, but the metal salt of benzoic acid, the metal salt of salicylic acid, the metal salt of alkyl salicylic acid, the metal salt of catechol, the metal containing bis which are used conventionally as a developer A compound selected from the group consisting of azo dyes, tetraphenyl borate derivatives, quaternary ammonium salts and alkylpyridinium salts, and resin type charge control agents containing polar groups are preferable, and those suitably combined with these may also be preferably used. have. The amount of these antistatic agents added to the toner solids is preferably in the range of 0.1 to 10% by weight.

As the organic solvent used when producing the oily component of the present invention, a general organic solvent can be used. Although the same thing as the dispersion liquid of a coloring agent is preferable, it may be different. For example, hydrocarbons such as toluene, xylene, hexane, halogenated hydrocarbons such as methylene chloride, chloroform, dichloroethane, alcohols such as methanol and ethanol, ethers such as tetrahydrofuran, methyl acetate, ethyl acetate, butyl acetate and the like And ketones such as acetone, acetone, methyl ethyl ketone and cyclohexynone. These may be used alone or in combination.

In the method for producing toner particles of the present invention, in view of easy control of the toner shape, particles are prepared by suspending and dispersing an oily component in which an aqueous dispersion of a binder resin and a colorant is dissolved or dispersed in an organic solvent in which the binder resin is dissolved. The method of doing is preferable. Thereafter, the toner particles can be taken out by removing the solvent by heating and / or depressurizingly removing or by adding a poor solvent.

Furthermore, the method of melt-dispersing a heated melt containing a dispersion of a binder resin and a colorant in an aqueous medium, followed by cooling to form toner particles, or suspending and dispersing a mixed solution containing at least a dispersion of a polymerizable monomer and a colorant in an aqueous medium. And the method of polymerizing a monomer after that is mentioned.

As a polymerizable monomer, (meth) acrylic acid ester monomers, such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and isobutyl (meth) acrylate, Carboxylic acid vinyl ester monomers, such as vinyl acetate, a styrene monomer, an olefin monomer, etc. are mentioned.

For example, the particles may be prepared by adding other materials, such as wax, to the dispersion of the colorant, or by dissolving or dispersing the other materials alone or in a suitable solvent and adding the dispersion together with the dispersion of the colorant, or the like in the preparation of the particles. .

Although water is mainly used as the aqueous medium of the present invention, it is possible to mix water-soluble solvents. As the water-soluble solvent, alcohols such as methanol and ethanol, acetone and the like can be used.

In addition, in view of particle size distribution of the toner, it is preferable to add a dispersant to the aqueous medium. As the dispersant, inorganic fine particles such as tricalcium phosphate, hydroxyapatite, calcium carbonate, titanium oxide, aluminum hydroxide, magnesium hydroxide, barium sulfate and silica can be used. The amount of the inorganic fine particles is preferably 0.1 to 20 parts by weight based on 100 parts by weight of the mother liquid. Moreover, 1 micrometer or less is preferable for the average particle diameter of an inorganic fine particle. Here, the mother liquid refers to a liquid after the oily component is dispersed in an aqueous medium.

In addition, it is preferable to add a water-soluble polymer to the aqueous medium as a dispersion stabilizer. Specific examples of the water-soluble polymer include alkali metal salts such as cellulose, hydroxypropylmethylcellulose, methyl cellulose, carboxymethyl cellulose, starch, polyvinyl alcohol, polyacrylic acid, and sodium and potassium, or alkaline earth metal salts such as calcium and magnesium. Can be mentioned. These form hydrophilic colloids and aim at dispersion stabilization.

As a stirring method for producing the particles, it is preferable to apply a shear, and a rotor stator type stirrer such as a homerizer or a colloid mill, an impeller type stirrer such as a dissolver, an ultrasonic stirrer, or the like is used.

Aeration drying apparatus, spray drying apparatus, rotary drying apparatus, airflow drying apparatus, fluidized bed drying apparatus, electrothermal heating drying apparatus, freeze drying apparatus and the like are known for drying, and any of them can be used.

The electrostatic latent image developer of the present invention uses the above-mentioned electrophotographic toner. The electrophotographic toner of the present invention is replaced with a magnetic powder by replacing all or part of the black coloring material with the magnetic monocomponent toner, and can be used as a monocomponent developer. As the magnetic powder, magnetite, ferrite, single metal such as cobalt, iron, nickel, or an alloy thereof can be used.

The electrophotographic toner of the present invention can also be used as a two-component developer by combining with a carrier. At this time, it is preferable that the carrier has a resin coating layer.

The image forming method of the present invention comprises a step of forming a latent image on a counseling member, a step of developing the latent image using a developer, and a step of transferring the formed toner image to a transfer member. In the step of developing the latent image using a developer, the developer contains a binder resin and a colorant, wherein the colorant has an acid value of 1 mg KOH / g or more and 27 mg KOH / g or less and an amine value of 1 or more and 100 or less. There is no particular limitation on the use of a developer containing an electroconductive electrophotographic toner dispersed by a polymer dispersant.

Each of these processes is a general process itself, and is described in, for example, Japanese Patent Laid-Open No. 56-40868, Japanese Patent Laid-Open No. 49-91231, and the like.

In addition, the image forming method of the present invention can be carried out using an image forming apparatus such as a copier, a facsimile machine or the like which is known per se.

Example

Example 1

Colorant C.I. Pigment Blue B 15: 3 20 parts by weight, 4 parts by weight of the polymer dispersant "Disparlon DA-725" (polyester amide amine salt, acid value: 20 mg KOH / g, amine number: 48, manufactured by Kusumoto Chemical) And 1 part by weight of the pigment derivative "Solsperse 5000" (Geneca) were added to 75 parts by weight of ethyl acetate, and dissolved / dispersed in a sand mill to adjust the colorant dispersion. In addition, "Disparlon DA-725" was used without solvent.

30 weight part of paraffin wax (melting point 89 degreeC) was used as a mold release agent, this was melt | dissolved by heat-dissolving in 270 weight part of ethyl acetate, and it quenched to prepare the wax dispersion.

As the binder resin, a polyester resin (Mw 20000, Tg 66 ° C., Tm 106 ° C.) made of a bisphenol A propylene oxide adduct, a bisphenol A ethylene oxide adduct, and a terephthalic acid derivative was used, and 136 parts by weight of the binder resin and the colorant described above. 34 parts by weight of the dispersion was added to 56 parts by weight of ethyl acetate, followed by stirring. Then, 75 parts by weight of the wax undispersed solution was added and stirred until uniform. This liquid was used as a liquid component.

On the other hand, after adding 40 weight part of calcium carbonate to 60 weight part of water, and disperse | distributing with a ball mill for 10 hours, 124 weight part of this calcium carbonate dispersion and the sodium salt of carboxymethyl cellulose "Serogen BS-H" (Daiichi Kogyo Seiyaku Co., Ltd.) 99 parts by weight of a 2% aqueous solution of iii) and 157 parts by weight of water were stirred for 5 minutes using a homerizer "ULTRA-TURRAX" (manufactured by IKA) to prepare an aqueous medium.

250 parts by weight of the oily component was added to 345 parts by weight of the aqueous medium, followed by stirring with a homerizer to obtain a mixed suspension. The solvent was removed by stirring with a propeller-type stirrer at room temperature and atmospheric pressure for 48 hours. Next, hydrochloric acid was added to remove calcium carbonate, followed by water cooling, drying, and classification to obtain a solid toner having an average particle diameter of 6.0 mu m.

Example 2

The colorant of Example 1 was prepared using C.I. Pigment Blue B 15: 3 from C.I. With Pigment Red R 57: 1, the polymer dispersant was replaced with "EFKA4010" (acid number: 25 mg KOH / g, amine number: 13, manufactured by EFKA CHEMICAL) from "Disparlon DA-725" and pigment derivative "Solsperse 5000" Magenta toner was obtained in the same manner as in Example 1 except that there was no addition. In addition, "EFKA4010" used what removed the solvent.

Example 3

The colorant of Example 1 was prepared using C.I. Pigment Blue B 15: 3 from C.I. With Pigment Red R 57: 1, the polymer dispersant was replaced with "Ajispa-PB711" (acid value: 2 mg KOH / g, amine number: 43, manufactured by Ajinomoto) from "Disparlon DA-725" and the pigment derivative "Solsperse 5000". Magenta toner was obtained in the same manner as in Example 1 except that there was no addition. In addition, "Ajispa-PB711" used what removed the solvent.

Comparative Example 1

A cyan toner was obtained in the same manner as in Example 1 except that neither the polymer dispersant "Disparlon DA-725" nor the pigment derivative "Solsperse 5000" was added.

Comparative Example 2

Example 1 except that the polymer dispersant "Disparlon DA-725" was changed to "Solsperse 24000SC" (acid value: 29 mg KOH / g, amine value: 39, manufactured by Geneca Co., Ltd.), which is a dispersant of another polymer type. The cyan toner was obtained in the same manner as in the following.

Toner Evaluation

10 g of each of the toners obtained and 100 g of a ferrite carrier coated with a polymethyl methacrylate were mixed in an environment having a temperature of 28 ° C. and a humidity of 80%, and the charge amount of the toner was measured by a blow-off method (blow-off method). . At this time, the Daejeon distribution was sharp. The particle size distribution of the toner was measured using a Coulter counter type TA-II (manufactured by Coulter). The surface shape of the toner was observed with a scanning electron microscope.

Next, 1 part by weight of "Silica R972" (manufactured by Nippon Aerosil Co., Ltd.) was added as an external additive to 100 parts by weight of the toner, and the silica external toner mixed with a sample mill for 1 minute was electro-full, full-color. An OHP fixing phase was produced by cleaning with a fixing machine of copier "A-color 935" (manufactured by Fuji Xerox) without fixing fuser oil.

Dispersibility of the colorant was observed by a transmission electron microscope of the toner cross section. Specifically, the toner sample was sealed with an epoxy resin, and then the cross section was cut and observed with a transmission electron microscope at an acceleration voltage of 100 KV.

1 is a transmission electron microscope photograph showing the particle structure of the toner of Example 1, and FIG. 2 is a transmission electron microscope photograph showing the particle structure of the toner of Comparative Example 1. FIG. As for the photograph magnification, the thing of Example 1 is 20,000 times, and the thing of Comparative Example 1 is 15,000 times.

In these photographs, small black spots are colorants. Although the magnification is somewhat different, when comparing Fig. 1 and Fig. 2, the toner of Comparative Example 1 contains agglomerates of colorants and a portion where no colorants are present. On the other hand, in the toner of Example 1, it was confirmed that the colorant was uniformly distributed in the toner, and no local aggregation of the colorant was found, so that the dispersion state was good. The dispersion state of the colorant was similarly confirmed for the toners of the other examples and the comparative examples.

The color development of OHP fixed the color image of the whole surface to the transparent sheet for OHP, projected it by the overhead project, and visually confirmed the sharpness of the projection image.

These evaluation results are shown in Table 1.

It can be seen from these examples and comparative examples that the electrophotographic toner of the present invention has good dispersion of the colorant in the toner, excellent chargeability, and uniform charge distribution. Moreover, it turns out that the color development property and light transmittance after fixing to an OHP sheet are also excellent. In addition, it can be seen that the colorant does not cause agglomeration even during production, and the dispersion stability is good.

As described above, according to the present invention, the dispersibility of the colorant is improved, the color development of the toner and the OHP light transmittance are improved, the colorant dispersion stability in the colorant dispersion is excellent, and the storage stability of the colorant dispersion is improved. The efficiency of particle manufacture is improved. Moreover, the selectivity of resin and a coloring agent is wide, and other additives, such as a wax, can be added.

At the same time, by dispersing the oil phase component in which the resin and the colorant are dissolved or dispersed in the organic solvent dissolving the toner constituent resin in an aqueous medium to produce particles, the colorant fine particles are produced by the difference in the affinity between the colorant and the oil phase component and the colorant and the aqueous medium. Is uniformly dispersed in the toner particles, thereby reducing the amount of colorant exposure on the surface of the toner. In addition, shape control is possible, and spherical shape of particles is easy. Therefore, the toner obtained by this manufacturing method is excellent in chargeability, fluidity, stability and transferability.

In addition, by applying this toner to a developer, in an image forming method for forming a latent image, an image with good image quality and excellent light transmittance in OHP can be formed.

In addition, since polycaprolactone resin is a biodegradable resin, there is an advantage that there is no environmental pollution.

Claims (18)

A binder resin and a coloring agent are contained, The binder resin is selected from a copolymer of polyester, polystyrene, styrene monomer and acrylic acid ester. The colorant has an acid value of 1 mg KOH / g or more and 27 mg KOH / g or less, and an amine number of 1 or more. Disperse | distributed by the polymer dispersing agent which consists of 100 or less polycaprolactone derivatives, A coloring agent is 1-50 weight part with respect to 100 weight part of binder resins, The said polymer dispersing agent contains 0.1 weight% or more and 10 weight% or less in toner. Incidental electrophotographic toner. The method of claim 1, An incident electrophotographic toner, wherein the polymer dispersant has compatibility with the binder resin. The method of claim 1, The capacitive electrophotographic toner according to claim 1, wherein the polycaprolactone derivative has a weight average molecular weight of 2000 or more and 10,000 or less. The method of claim 1, The addition amount of the polycaprolactone derivative is 1 part by weight or more and 50 parts by weight or less with respect to 100 parts by weight of the colorant. The method of claim 1, An incident electrostatic toner, further comprising a releasing agent. The method of claim 5, A toner for non-electric transfer photography, wherein the content of the release agent is 1 part by weight to 50 parts by weight with respect to 100 parts by weight of the incidentally conductive electrophotographic toner. The method of claim 5, The incident electrostatic photo toner, characterized in that the melting point of the release agent is 120 ℃ or less. An electrostatic latent image developing agent using the capacitive electrophotographic toner according to claim 1 or 2 or 3 or 4 or 5 or 6 or 7. The method of claim 8, The latent electrostatic latent developer is a two-component developer comprising a carrier and a toner. The method of claim 9, An electrostatic latent image developer, wherein the carrier has a resin coating layer. The binder resin selected from the copolymer of polyester, polystyrene, a styrene monomer and an acrylic acid ester, and an acid value of 1 mg KOH / g or more and 27 mg KOH / g or less and dispersed by a polymer dispersant of a polycaprolactone derivative having an amine value of 1 or more and 100 or less. The colorant is dissolved or dispersed in an organic solvent to adjust the oil phase component, A method for producing toner by dispersing the oil phase component in an aqueous medium, wherein the colorant is from 1 to 50 parts by weight based on 100 parts by weight of the binder resin, and the polymer dispersant is from 0.1 to 10% by weight in the toner. A method for producing an incident electrostatic toner, which is as follows. The oil phase component is adjusted by dissolving or dispersing a colorant dispersed in a polymerizable monomer having an acid value of 1 mg KOH / g or more and 27 mg KOH / g or less and an amine value of 1 or more and 100 or less in the polymerizable monomer, and the oil phase component is added to an aqueous medium. A method for producing an incident electrostatic toner, characterized in that the particles are dispersed and polymerized to produce particles. The method according to claim 11 or 12, A method for producing an incidental electrophotographic toner, wherein the colorant dispersion obtained by dispersing the colorant in the organic solvent in advance with the polymer dispersant is dissolved or dispersed in an organic solvent together with a binder resin or a polymerizable monomer. . The method according to claim 11 or 12, wherein A blending ratio of the colorant and the organic solvent is in the range of 5:95 to 50:50. The method according to claim 11 or 12, wherein A method for producing an incident electrostatic toner, wherein the aqueous medium contains an inorganic dispersant. The method of claim 15, And the aqueous medium further contains a dispersion stabilizer. The method of claim 15, The content of the inorganic dispersant is 0.1 part by weight to 20 parts by weight with respect to 100 parts by weight of the mother liquor. An image forming method comprising the steps of: forming a latent image on a counseling member; developing the latent image using a developer; and transferring the formed toner image to a transfer member; An image forming method characterized by using a latent image developer.