JPH1124308A - Toner for electrophotography and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain toner excellent in offset resistance, electrifying property, fluidity, stability, excellent color developing property and OHP transparency by using a releasing agent dispersed liquid obtained by depositing releasing agent after dissolving it in organic solvent or suspending the releasing agent in the organic solvent and then comminuting and/or dispersing it by a medium as the releasing agent. SOLUTION: In order to disperse the globular particulates of the releasing agent in toner, the releasing agent dispersed liquid obtained by depositing the releasing agent after previously dissolving it in the organic solvent or suspending the releasing agent in the organic solvent and then comminuting and/or dispersing it by the medium is used as the releasing agent to be dispersed in the organic solvent in which a binding resin is dissolved. Before dispersing the releasing agent in the organic solvent together with the resin and a colorant and adjusting an oil phase component, the releasing agent is previously globularly dispersed in the solvent in small dispersion units. Thus, the particles of the releasing agent to be dispersed in the obtained toner particles are dispersed globularly in small dispersion units, and both the offset ability and the fixing ability of the toner are satisfied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner for developing an electrostatic image used in electrophotography and a method for producing the same.

[0002]

2. Description of the Related Art A kneading and pulverizing method has been known as a method for producing a toner for developing an electrostatic image conventionally used in electrophotography. The kneading and pulverizing method, which is a method for obtaining the toner of the formula (1), was generally used. To the toner obtained by the kneading and pulverizing method, a wax such as a low-molecular-weight polyolefin is added as a release agent in the toner in order to prevent so-called offset in which the toner remains on the fixing roller. This release agent such as a low molecular weight wax is effective in preventing offset, but causes filming to adhere to a photoreceptor or a carrier, and has problems in cleaning properties and stability over time. To prevent this filming, for example, JP-A-62-143061 and JP-A-3-14864.
No. 9 proposes a method for reducing the particle size of a release agent such as wax. Also, as a color toner, polyolefin wax is dispersed in polyester by kneading (Japanese Patent Laid-Open No. 3-107869), or OHP is used.
A toner prepared by a suspension polymerization method containing a polyalkylene having a reduced crystallinity in order to improve the transparency (Japanese Patent Laid-Open No. 197191/1993) is known. On the other hand, after dispersing the release agent in a rod-like or needle-like shape in the resin composition, the wax domain is sheared to increase the dispersibility of the wax (Japanese Patent Application Laid-Open No. 6-289645), and to prevent filming. In order to prevent wax separation at the time of pulverization, the shape of wax is changed to a spindle shape (Japanese Patent Laid-Open No. 7-161).
144, JP-A-7-161145), and disperse spherical wax particles having a small particle size (JP-A-8-328).
No. 293).

However, in a toner prepared by kneading and pulverizing with the above-mentioned wax, a large amount of the wax is unevenly distributed on the surface of the obtained particles, so that (1) the toner's chargeability, fluidity, life and the like are deteriorated. (2) poor dispersibility of a wax having a low softening point;
For example, there is a problem that a low-molecular polyester of sharp melt for a color toner cannot be used. On the other hand, as a method of preparing toner particles that solves the above-mentioned problems other than the kneading and pulverizing method, there is known a method of granulating an oil phase component in which a polyester resin is dissolved in an organic solvent in an aqueous medium containing an inorganic dispersant. (JP-A-7-152202, JP-A-7-168395, and JP-A-7-168396). According to these manufacturing methods, although the wax is less likely to be exposed on the surface, the dispersion unit of the wax dispersed in the toner in the granulation step is increased, the light transmittance of the particles is reduced, and when used as a color toner, There were drawbacks such as low color development and poor OHP transparency. In addition, when the amount of wax exposed on the surface is small, the effect of preventing the offset property by the wax is weak. For example, a wax which is unevenly distributed in the center of the toner particles has a small contribution to the offset resistance, and more wax is used. It had to be added. On the other hand, as a dispersion method of a release agent such as wax,
Although there are stirring, ultrasonic treatment, and the like, when these are used, the fine particles are insufficiently formed and sufficient dispersion cannot be obtained. In addition, it is possible to reduce the particle size by applying strong shear, impact, cavitation, etc. with a pressure homogenizer, etc., but it is not possible to make the particles spherical, and the temperature rises further and the release agent Re-agglomeration occurs, and sufficient dispersion of the release agent is not always obtained, especially for a release agent having a low melting point.
There was a disadvantage that reaggregation further progressed and dispersion of the release agent became worse.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and is directed to a toner in which spherical fine particles of a release agent are dispersed in a toner. The toner has offset resistance, chargeability, and fluidity. An object of the present invention is to provide an electrophotographic toner having excellent color stability and excellent transparency and OHP transparency, and a method for producing the same.

[0005]

The electrophotographic toner of the present invention comprises an oil phase component obtained by dissolving or dispersing at least a binder resin, a colorant, and a release agent in an organic solvent that dissolves the binder resin. And an electrophotographic toner produced by a production method comprising a step of granulating the oil phase component by dispersing the oil phase component in an aqueous medium, wherein the release agent is previously dissolved in an organic solvent and then precipitated. A toner for electrophotography, which is a dispersion of a release agent obtained by being pulverized and / or dispersed in a medium after being subjected to or after being suspended in an organic solvent in advance.

In the present invention, one method of dispersing the spherical fine particles of the release agent in the toner is to dissolve at least the binder resin, the colorant, and the release agent in an organic solvent in which the binder resin is dissolved. Or dispersing the oil phase component to prepare an oil phase component, and dispersing the oil phase component in an aqueous medium to granulate the electrophotographic toner. As a release agent to be dispersed in, a dispersion of the release agent obtained by dissolving in an organic solvent in advance and then precipitating or suspending in an organic solvent in advance and then pulverizing and / or dispersing with a medium is used. The method used is mentioned. The toner of the present invention preferably satisfies the condition of the shape factor represented by the following formula (1).

F ≦ 1.25 (1) (where f = a / b, a is the average length of the major axis of the release agent particles, and b is the minor axis of the release agent particles) In the present invention, the spherical fine particles of the release agent dispersed in the toner have an average particle diameter in the range of 0.01 to 1.5 μm and a shape having the shape factor ( f), f ≦ 1.2
It is desirable that the release agent spherical fine particles satisfy the conditions of 5. One of the methods for producing such a toner includes a step of dissolving or dispersing at least a binder resin, a colorant, and a release agent in an organic solvent that dissolves the binder resin to prepare an oil phase component. And a method for producing an electrophotographic toner comprising a step of dispersing the oil phase component in an aqueous medium and granulating, wherein an organic solvent is used in advance as a release agent for dispersing in an organic solvent in which the binder resin is dissolved. After dissolving in the precipitate
Alternatively, when using a dispersion of a release agent obtained by previously suspending in an organic solvent and then pulverizing and / or dispersing with a medium, and pulverizing and / or dispersing with a medium, at least the release agent is used. And the temperature of the dispersion containing the organic solvent is set to 40 ° C. or lower. If the temperature of the dispersion liquid exceeds 40 ° C., the release agent that has become spherical and fine particles reaggregates, and it becomes impossible to obtain the desired release agent spherical fine particles.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The toner of the present invention contains at least a binder resin, a colorant and a release agent. Examples of the binder resin used in the present invention include styrenes such as styrene, parachlorostyrene and α-methylstyrene, methyl acrylate, ethyl acrylate, n-propyl acrylate, lauryl acrylate, and 2-ethylhexyl acrylate. , Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate,
Lauryl methacrylate, esters having a vinyl group such as 2-ethylhexyl methacrylate, vinyl nitriles such as acrylonitrile and methacrylonitrile, vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether, vinyl methyl ketone, vinyl ethyl ketone, and vinyl Vinyl ketones such as isopropenyl ketone,
Polymers such as monomers such as polyolefins such as ethylene, propylene and butadiene, or copolymers obtained by combining two or more thereof, or mixtures thereof, epoxy resins, polyester resins, polyurethane resins, polyamide resins, and cellulose resins And non-vinyl condensed resins such as polyether resins, and mixtures of these with the vinyl resins, and graft polymers obtained when polymerizing vinyl monomers in the presence of these.

The polyester resin is obtained by polycondensation of an alcohol component and a carboxylic acid component, and each component includes the following. As the alcohol component, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, cyclohexanedimethanol,
Xylylene glycol, dipropylene glycol, polypropylene glycol, bisphenol A, hydrogenated bisphenol A, bisphenol A ethylene oxide, bisphenol A propylene oxide, sorbitol,
Dihydric or higher alcohols such as glycerin and alcohol derivatives are exemplified. As the carboxylic acid component, maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, adipic acid, trimellitic acid, pyromellitic acid, cyclopentanedicarboxylic acid, succinic anhydride, trimellitic anhydride, anhydride Examples thereof include divalent or higher carboxylic acids such as maleic acid and dodecenyl succinic anhydride, carboxylic acid derivatives, and anhydrides thereof. Two or more alcohol components and two or more carboxylic acid components may be used in combination.

As a solvent for dissolving the binder resin and constituting the oil phase component, a usual organic solvent for dissolving each resin is used. For example, hydrocarbons such as toluene, xylene and hexane, halogenated hydrocarbons such as methylene chloride, chloroform and dichloroethane, alcohols such as methanol and ethanol, ethers such as tetrahydrofuran, esters such as methyl acetate, ethyl acetate and butyl acetate. , Acetone, methyl ethyl ketone, cyclohexanone and the like, and these may be used alone or as a mixture of a plurality of solvents. The mixing ratio of these solvents and resin is such that resin / solvent = 5/95 to 50/50.
Is desirable.

The release agent in the present invention includes petroleum wax such as paraffin wax, paraffin wax, microcrystalline wax, mineral wax such as montan wax, animal and plant wax such as carnauba wax, polyolefin wax, oxidized polyolefin wax, Fischer-Tropsch Examples thereof include synthetic wax such as wax, ester wax, and ether wax. It is desirable that the melting point of the release agent be 120 ° C. or lower and lower from the viewpoint of the offset resistance of the toner. In addition, the melting point is preferably from 40 to 120 ° C, and more preferably from 50 to 100 ° C, from the viewpoint of handling properties, production simplicity, and storage stability. However,
It can also be applied to wax that is liquid at room temperature, that is, a release agent having a melting point of less than 40 ° C.

The toner of the present invention is characterized in that spherical fine particles of a release agent are dispersed therein.
One of the production methods is to disperse the release agent in a small dispersion unit and in a spherical form in the solvent before dispersing the release agent together with the resin and the colorant in the organic solvent to adjust the oil phase component. It is characterized by. By previously dispersing the release agent in a small dispersion unit and in a spherical shape, the particles of the release agent dispersed in the obtained toner particles can be formed in a small dispersion unit and in a spherical shape. Both the offset property and the fixing property can be satisfied. The release agent particles in the release agent dispersion have an average particle size of 0.01 to 1.5.
μm, and the shape factor (f), f ≦
Spherical fine particles satisfying the condition of 1.25 are preferred. In particular, the average particle diameter is desirably in the range of 0.1 to 0.5 μm. When the average particle size of the release agent is less than 0.01 μm, the effect of improving the offset resistance is reduced, and
If it exceeds, the transmittance in OHP is reduced, and filming is liable to occur. The average particle size of the release agent particles is determined by a laser diffraction / scattering type particle size distribution analyzer (for example, LA-700 or LA-910 manufactured by HORIBA, Ltd.).
And the like.

As a method for producing a dispersion of spherical fine particles of a release agent, the release agent is dissolved and precipitated in an organic solvent in advance, or after the suspension is previously suspended in an organic solvent, And then pulverizing and / or dispersing the release agent with a medium. In order to further reduce the average particle size of the dispersed release agent particles, when pulverizing and / or dispersing the release agent in a medium, the temperature of the dispersion containing at least the release agent and the organic solvent should be 40 ° C. or less. Method. As the organic solvent used in the method for producing a release agent dispersion, the same kind of organic solvent that can dissolve the binder resin can be used alone, or a plurality of kinds can be used as a mixture. The organic solvent used for forming the spherical fine particles of the release agent and the organic solvent constituting the oil phase component need not always be the same. However, if the same one is used, there is no need to consider the compatibility between the solvents, it is easy to control the blending amount of the organic solvent constituting the oil phase component, and the dispersion of the release agent is stable in the oil. It has the advantage that the phase components can be adjusted.

The amount of the organic solvent used for finely dispersing the release agent is preferably about 1 to 20 parts by weight of the organic solvent per 1 part by weight of the release agent. If the amount of the organic solvent is small, uniform fine dispersion cannot be obtained, and if the amount is too large, the dispersion density of the release agent is reduced, and when mixed with the oil phase component, the amount of the solvent is excessive and the productivity is reduced.

As a method for obtaining a coarse dispersion of the release agent, a method in which the release agent is dissolved in an organic solvent and then precipitated, or a method in which the release agent is suspended in the organic solvent, may be mentioned. As the former method, a method in which the release agent is dissolved in the organic solvent by adding / stirring or adding / stirring / heating the organic solvent, and then cooled to precipitate the release agent is adopted. As the latter method, a method in which a particulate release agent is suspended in an organic solvent is used. Further, when cooling and precipitating, ultrasonic treatment or the like may be used in combination.

The coarse dispersion of the release agent thus obtained is pulverized and / or dispersed using a medium to form a release agent of spherical fine particles. As a specific method using a medium, a so-called medium mill or medium stirring mill such as a ball mill, a sand mill, an attritor, a co-ball mill, a DCP mill, and a fine mill can be used. The release agent particles are reduced to smaller particles, that is, having an average particle size of 0.01 to 1.5.
In order to obtain spherical particles in the range of μm, when the release agent is pulverized and / or dispersed in a medium, the temperature of the dispersion in the pulverized and / or dispersed region must be 40 ° C. or less. However, for this purpose, it is necessary to effectively cool the heat generated by the dispersion treatment in the pulverization and / or dispersion region, and a device having a mechanism capable of effectively cooling the dispersion liquid, for example, a sand mill, an attritor, Koball mill,
Grinding and / or dispersion is performed using a DCP mill, a fine mill, or the like. In order to form a release agent having a smaller particle size and a more spherical shape, it is necessary to control the temperature of the dispersion in the pulverization and / or dispersion region to 20 ° C. or lower, optimally 10 ° C. or lower. . Apparatuses having a mechanism capable of efficiently cooling a dispersion include, for example, a co-ball mill, DC
P mills, fine mills and the like are preferable, and more preferably, a DCP mill capable of cooling the rotor / stator portion,
A fine mill or the like is used.

In the present invention, the medium used for preparing the dispersion liquid of the spherical fine particles of the release agent may be cylindrical, spherical, etc., but the efficiency of pulverization and dispersion and the adaptability to a dispersion apparatus can be used. Considering the properties, a spherical shape is preferable. The size of the spherical media is preferably from 0.1 to 5 mm in diameter, but is preferably from 0.1 to 2 mm in order to effectively make the shape of the release agent spherical and fine. When the release agent is pulverized and / or dispersed in a medium after being dissolved or suspended in the organic solvent, the temperature of the dispersion in the pulverized and / or dispersed region is preferably 40 ° C. or less, and is preferably 20 ° C
The following is optimally, and preferably 10 ° C. or less. If the temperature of the dispersion exceeds 40 ° C., the release agent which has become spherical and fine particles is reaggregated, and it becomes impossible to obtain the desired release agent spherical fine particles.

As the coloring agent of the present invention, known organic or inorganic pigments and dyes, and oil-soluble dyes can be used. For example, C.I. I. Pigment Red 48: 1, C.I.
I. Pigment Red 57: 1, C.I. I. Pigment Red 122, C.I. I. Pigment Yellow 17, C.I.
I. Pigment Yellow 97, C.I. I. Pigment Yellow 12, C.I. I. Pigment Blue 15: 1, C.I.
I. Pigment Blue 15: 3, Lamp Black (C.I.
I. No. 77266), Rose Bengal (C.I.N.
o. 45432), carbon black, acetylene black, aniline black, nigrosine dye (CIN)
o. 50415B), metal complex dyes, derivatives of metal complex salt dyes, and mixtures thereof. These colorants are added at a ratio of about 1 to 50 parts by weight with respect to 100 parts by weight of the resin, and preferably 2 to 20 parts by weight.

The oil phase component in the production method of the present invention is prepared by dissolving or dispersing a binder resin, a colorant, a release agent, and the like in an organic solvent in which the binder resin is dissolved. As other additives that can be blended with the phase component,
Examples thereof include a toner fluidity adjusting agent and a charge controlling agent, and these can be arbitrarily added as long as the effects of the present invention are not impaired. Additives that control the fluidity of the toner include silica, aluminum oxide, magnetite and various ferrites, cupric oxide, nickel oxide,
Examples include various metal oxides such as zinc oxide, zirconium oxide, titanium oxide, and magnesium oxide, and appropriate mixtures thereof. The amount of these additives is preferably 5% by weight or less based on the binder resin, and more preferably 0.05 to 3% by weight.

As the charge control agent that can be used in the present invention, those conventionally used in developers can be used, but the metal salts of benzoic acid and metal of salicylic acid used in powder toners for xerography can be used. Salts, metal salts of alkylsalicylic acid, metal salts of catechol, metal-containing bisazo dyes, tetraphenylborate derivatives, quaternary ammonium salts, compounds selected from the group consisting of alkylpyridinium salts, and the like, in addition to those suitably combined. It can be used preferably. The amount of the charge control agent to be added to the toner solid content is generally 10% by weight or less, and more preferably 0.01 to 5% by weight.

As described above, the oil phase component obtained by dissolving or dispersing the toner composition containing a binder resin, a colorant, a release agent and the like in an organic solvent is then mixed and stirred in an aqueous medium. Granulated to form toner particles. As the aqueous medium used here, water is mainly used, but a water-soluble solvent may be mixed and used. The use amount of the aqueous medium with respect to the oil phase component is as follows: oil phase / aqueous medium = 60/40
The range is preferably from 10 to 90/90, and more preferably from 50/50 to 25/75 from the viewpoint of dispersibility. When dispersing the oil phase component in the aqueous medium, a dispersant may be added. When you add a dispersant,
This has the effect of narrowing the particle size distribution of the resulting toner particles.
Examples of the dispersant include tricalcium phosphate, hydroxyapatite, calcium carbonate, titanium oxide, aluminum hydroxide, magnesium hydroxide, barium sulfate, silica, cellulose, starch, polyvinyl alcohol, and polyacrylic acid. The amount of the dispersant depends on the aqueous medium 10
It is preferably 20 parts by weight or less based on 0 parts by weight. As a method of granulation, it is preferable to apply shearing when mixing and stirring the oil phase component in an aqueous medium, and a rotor-stator type disperser, for example, a colloid mill or a homogenizer, a known stirrer such as a cooking mixer, Mixers and dispersers can be used. Granulation is 0-70 ° C
It is preferable to perform the reaction for 1 minute to 1 hour while applying a shearing force in the temperature range described above.

By removing the solvent after the granulation and further removing the remaining dispersant and the like, it is possible to obtain toner particles having a uniform particle diameter in which spherical fine particles of a release agent are finely dispersed in the particles. . The average dispersion unit of the release agent and the shape of the release agent of the obtained toner particles preferably have a particle diameter in the range of 0.01 to 1.5 μm as described above, and
The shape of the particles is spherical particles having the shape factor (f), f ≦ 1.25, and the dispersion state of the release agent is determined by taking a cross section of the toner particles in an electron microscope (TEM) photograph and examining the dispersion unit of the release agent. It can be obtained by measuring the diameter of the cross section.

Since the toner for electrophotography obtained by the production method of the present invention is granulated in an aqueous medium, the shape can be easily controlled and uniform spherical toner particles can be easily obtained. In addition, since the release agent is finely dispersed and contained in the particles, the transferability and the fixability of the toner to a support such as paper are good, and no offset is observed without the oil of the fixing roll. It has excellent properties of high permeability.

Since the toner particles for electrophotography of the present invention granulate the oil phase component in an aqueous medium, the difference in affinity between the release agent and the oil phase component and the affinity between the release agent and the aqueous medium causes the release. The releasing agent particles are hardly exposed on the surface, and the releasing agent particles dispersed in the toner are spherical, preferably the shape factors (f), f
By making the spherical fine particles of ≦ 1.25, the release agent is hardly exposed on the toner particle surface, the toner fluidity is improved, and the chargeability is improved. Therefore, even if a release agent having a low melting point is used, exposure to the surface is small, and there is no problem in fluidity and storage stability. Further, by containing a release agent in the toner, fixing without oil is possible, the toner has excellent coloring properties and OHP transparency, and has good fluidity and preservability of the toner, and good chargeability. Further, in the electrophotographic toner of the present invention, the release agent to be dispersed in the organic solvent, after previously dissolved and precipitated in the organic solvent, or after previously suspended in the organic solvent, in the medium When using a dispersion of the release agent obtained by pulverizing and / or dispersing the release agent and pulverizing and / or dispersing with a medium, the temperature of the dispersion containing at least the release agent and the organic solvent is adjusted. The toner for electrophotography obtained by the production method including the step of maintaining the temperature at 40 ° C. or lower is such that the release agent in the toner has a dispersion unit within the range of 0.01 to 1.5 μm on average, and the shape has the shape factor. (F), dispersed as spherical fine particles satisfying f ≦ 1.25. As a result, in addition to the properties of the toner described above, this toner can prevent light scattering by the release agent,
Has an effect of being excellent in transparency. In addition, the toner can efficiently exhibit the performance of the release agent because the release agent quickly melts.

The diameter of the toner particles in the present invention is not particularly limited, but when the diameter of the toner particles to be obtained is made smaller, the diameter of the release agent particles dispersed in the toner particles becomes 1. It is desirable to eliminate release agent particles of large dispersion units exceeding 5 μm. By doing so, the effect of spheroidizing the particles of the release agent is increased, and excellent characteristics are obtained even in the case of a small particle size toner which aims to improve image quality, for example, a small particle size toner particle of 6 μm or less. Obtainable.

Further, the toner for electrophotography of the present invention is a developer used in an image forming method including a step of forming a latent image on an image carrier and a step of developing the latent image using a developer. Can be applied as

[0026]

【Example】

(Example 1) Paraffin wax (trade name: HNP (high-purity purified paraffin wax) manufactured by Nippon Seisaku, melting point 89)
℃) 30 parts by weight to 250 parts by weight of ethyl acetate, 73
A wax dispersion at 25 ° C. obtained by heating and dissolving at 25 ° C. and precipitating by cooling is used together with zirconia media having a diameter of 0.5 mm in a DCP mill SF-12 (manufactured by Eirich Japan).
, And pulverized and / or dispersed to a unit integrated power of 0.50 kWh / kg to obtain a wax ethyl acetate dispersion. At this time, the temperature of the wax dispersion in the pulverization and / or dispersion region was 15 ° C. The average particle diameter of the wax is measured by a laser diffraction / scattering particle size distribution analyzer LA-91.
It was 0.90 μm when measured at 0 (manufactured by Horiba Seisakusho) (the particle size measured by LA-910 indicates 50% frequency particle size−median size−by volume). When the shape of the wax in the wax dispersion was observed with a scanning electron microscope (SEM), the average length (a) of the major axis of the wax was 0.95 μm, and the average length (b) of the minor axis of the wax was 0.
80 μm, and the shape factor (f = a / b) was 1.19. The measurement was obtained from an SEM photograph by averaging 20 wax particles.

100 parts by weight of a polyester resin comprising bisphenol A propylene oxide adduct, bisphenol A ethylene oxide adduct, and a succinic acid derivative (weight average molecular weight: 15,000, Tg 64 ° C., Tm 102 ° C.); I. 4 parts by weight of CI Pigment Blue 15: 3,
After dispersing 80 parts by weight of ethyl acetate in a ball mill for 10 hours,
36 parts by weight of an ethyl acetate dispersion of wax was added, and the mixture was stirred well until the mixture became uniform to prepare an oil phase component. 60 parts by weight of calcium carbonate and 40 parts by weight of water were dispersed in a ball mill for 10 hours to obtain a calcium carbonate dispersion. 7 parts by weight of this calcium carbonate dispersion and 100 parts by weight of a 2% by weight aqueous solution of cellogen BS-H (manufactured by Daiichi Kogyo Seiyaku) are placed in a cooking mixer MX-915C (manufactured by Matsushita Electric), mixed for 5 minutes, and mixed with an aqueous phase. Make a liquid. 100 parts by weight of the oil phase liquid was added to this aqueous phase liquid, and mixed with a cooking mixer for 6 minutes.
Heat in a hot water bath to remove the organic solvent. 1N 6N hydrochloric acid
After removing calcium carbonate by adding 00 parts by weight,
After drying and classification, a solid toner having an average particle diameter of 7.1 μm was obtained. Looking at the SEM photograph, the shape is almost spherical. In order to confirm the shape of the wax in the toner, the cross section of the toner particles is taken with an electron microscope (TEM) photograph, and the average length (a) of the major axis of the wax is set to 1 by measuring the diameter of the dispersion unit cross section of the wax. .20 μm, the average length (b) of the minor axis of the wax was 0.98 μm, and the shape factor (f =
a / b) was 1.22. In a transmission electron microscope (TEM) photograph of the cross section of the toner, the wax was dispersed inside the toner and was not visible on the surface of the toner particles.

1 part by weight of silica R972 (manufactured by Nippon Aerosil) was mixed with 100 parts by weight of the toner for 1 minute using a sample mill. The thus-obtained silica externally added toner was subjected to A-color.
Using 935 (manufactured by Fuji Xerox), image formation was evaluated without fixing fuser oil, and the results are shown in Table 1. The evaluation method is as follows. As for the image quality, the color tone, the image density, the presence or absence of fog, and the fixability to paper and OHP were visually observed at the initial stage and after 1000 copies. For the offset, the presence or absence of toner attached to the fixing roll at the initial stage and after copying 1000 sheets was visually checked. The light transmittance of the OHP was measured by fixing a solid image to the OHP and then measuring the light transmittance at a wavelength at which the colorant was not absorbed. The wax diameter in the toner was determined from the average value of ten horizontal diameters randomly selected from a TEM photograph of the cross section of the toner. Storage stability is 50 ℃
Was examined for the presence or absence of aggregation after standing for 3 hours. The transferability was visually confirmed immediately after the transfer to paper by the presence or absence of toner on the surface of the photoreceptor.

(Example 2) The temperature of the wax dispersion liquid being treated with DCP mill SF-12 (manufactured by Eirich Japan) was 5.
A wax dispersion in ethyl acetate was obtained in the same manner as in Example 1 except that the temperature was 0 ° C. The average particle size of the wax is
It was 0.50 μm when measured with a laser diffraction / scattering particle size distribution analyzer LA-910 (manufactured by Horiba, Ltd.).
When the shape of the wax in the wax dispersion was observed with a scanning electron microscope (SEM) in the same manner as in Example 1, the average length (a) of the major axis of the wax was 0.55 μm, and the average length of the minor axis of the wax was (B) was 0.48 μm, and the shape factor (f = a / b) was 1.15. Bisphenol A
Polyester resin comprising propylene oxide adduct, bisphenol A ethylene oxide adduct, and succinic acid derivative (weight average molecular weight: 15,000, Tg 64 ° C,
Tm 102 ° C) 100 parts by weight, C.I. I. After 3 parts by weight of CI Pigment Red 57 and 100 parts by weight of ethyl acetate were dispersed in a sand mill for 5 hours, 36 parts by weight of a wax ethyl acetate dispersion was added, and the mixture was thoroughly stirred until the mixture became uniform to prepare an oil phase liquid. 60 parts by weight of calcium carbonate and 40 parts by weight of water were dispersed in a ball mill for 10 hours to obtain a calcium carbonate dispersion. 6 parts by weight of this calcium carbonate dispersion and cellogen BS
100 parts by weight of a 2% by weight aqueous solution of -H (manufactured by Daiichi Kogyo Seiyaku) was put into a cooking mixer MX-915C (manufactured by Matsushita Electric) and mixed for 5 minutes to prepare an aqueous phase liquid. Add 50 parts by weight of the oil phase liquid to the aqueous phase liquid, and add
After mixing for minutes, the mixture was heated in a water bath at 40 ° C. to remove the organic solvent. After 100 parts by weight of 6N hydrochloric acid was added to remove calcium carbonate, the particles were washed with water, dried and classified to have an average particle diameter of 6.1 μm.
Was obtained. The SEM photograph showed that the shape was almost spherical. In order to confirm the shape of the wax in the toner, it was observed with a TEM photograph in the same manner as in Example 1. As a result, the average length (a) of the major axis of the wax was 0.68 μm,
The average length (b) of the minor axis of the wax was 0.57 μm, and the shape factor (f = a / b) was 1.19. In a transmission electron microscope (TEM) photograph of the cross section of the toner, the wax was dispersed inside the toner and was not visible on the surface of the toner particles. 100 parts by weight of toner was mixed with 1 part by weight of silica R972 (manufactured by Nippon Aerosil Co., Ltd.) for 1 minute using a sample mill. The results obtained are shown in Table 1.

(Example 3) 250 parts by weight of ethyl acetate was added to 30 parts by weight of microcrystalline wax (trade name: Hi-Mis-3080, manufactured by Nippon Seisaku, melting point: 84 ° C), and the mixture was heated and dissolved at 73 ° C. While maintaining the temperature at 65 ° C., the wax was precipitated by cooling to obtain a crude wax dispersion. This crude wax dispersion is mixed with zirconia media having a diameter of 0.5 mm in a DCP mill SF-12 (manufactured by Nippon Eirich Co.) and dispersed until the unit integrated power becomes 0.20 kWh / kg while pulverizing and / or dispersing. The liquid temperature is cooled to 5 ° C., and then the unit integrated power is 0.6 at the dispersion temperature of 5 ° C.
The wax was ground and / or dispersed until it became 5 kWh / kg to obtain a wax ethyl acetate dispersion. The average particle diameter of the wax is measured by a laser diffraction / scattering particle size distribution analyzer LA-91.
When measured at 0 (manufactured by Horiba, Ltd.), it was 0.58 μm. When the shape of the wax in the wax dispersion was observed with a scanning electron microscope (SEM) in the same manner as in Example 1,
The average length (a) of the major axis of the wax was 0.64 μm, the average length (b) of the minor axis of the wax was 0.55 μm, and the shape factor (f = a / b) was 1.16. .

Styrene-butyl acrylate 80:20
100 parts by weight of a copolymer resin (weight average molecular weight: 40000, number average molecular weight: 15000), C.I. I. 6 parts by weight of Pigment Yellow 17, after 5 hours dispersed 1000 parts by weight of toluene in a sand mill, adding ethyl acetate dispersion 72 parts by weight of the word box, to prepare an oil phase liquid stirred well until uniform. 60 parts by weight of calcium carbonate and 40 parts by weight of water were dispersed in a ball mill for 10 hours to obtain a calcium carbonate dispersion. 6 parts by weight of this calcium carbonate dispersion and 100 parts by weight of a 2% by weight aqueous solution of cellogen BS-H (Daiichi Kogyo Seiyaku Co., Ltd.) were subjected to a tabletop colloid mill (manufactured by Nippon Seiki Seisakusho) to obtain 50 parts by weight.
An aqueous phase solution was prepared by mixing at 00 rpm for 5 minutes. 50 parts by weight of the oil phase liquid is added to this aqueous phase liquid,
After mixing for minutes, the organic solvent is removed under reduced pressure in a water bath at 25 ° C. After 100 parts by weight of 6N hydrochloric acid was added to remove calcium carbonate, the particles were washed with water, dried, and classified to have an average particle size of 7.4 μm.
m of solid toner was obtained. Looking at the SEM photograph, the shape was almost spherical. In order to confirm the shape of the wax in the toner, it was observed with a TEM photograph in the same manner as in Example 1. As a result, the average length (a) of the major axis of the wax was 0.70 μm,
The average length (b) of the minor axis of the wax was 0.58 μm, and the shape factor (f = a / b) was 1.21. In a transmission electron microscope (TEM) photograph of the cross section of the toner, the wax was dispersed inside the toner and was not visible on the surface of the toner particles. 100 parts by weight of toner was mixed with 1 part by weight of silica R972 (manufactured by Nippon Aerosil Co., Ltd.) for 1 minute with a sample mill, and the image was evaluated using A-color 935 (manufactured by Fuji Xerox) without using a fuser oil. The results obtained are shown in Table 1.

Example 4 30 parts by weight of paraffin wax (trade name: HNP (high-purity purified paraffin wax), manufactured by Nippon Seiro, melting point: 89 ° C.) was dissolved by heating at 73 ° C. in 250 parts by weight of ethyl acetate, and then 60 parts by weight. The wax coarse dispersion obtained by precipitating the wax while maintaining the temperature at ° C. was subjected to ultrasonic treatment (ultrasonic oscillation frequency 28 ± 2 kHz, ultrasonic oscillation output density 0.601 W / cm ² ) to obtain a coarse wax dispersion. .
A 25 ° C. crude wax dispersion was charged into a DCP mill SF-12 (manufactured by Eirich Japan) together with zirconia media having a diameter of 0.3 mm, and the unit integrated power was 0.70 kW.
h / kg to obtain a wax-ethyl acetate dispersion. At this time, the temperature of the wax dispersion in the pulverization and / or dispersion region was 5 ° C.
The average particle size of the wax was 0.40 μm as measured with a laser diffraction / scattering type particle size distribution analyzer LA-910 (manufactured by Horiba, Ltd.). When the shape of the wax in the wax dispersion was observed with a scanning electron microscope (SEM), the average length (a) of the major axis of the wax was 0.45 μm,
The average length (b) of the minor axis of the wax was 0.39 μm, and the shape factor (f = a / b) was 1.15.

Styrene-butyl acrylate 80:20
100 parts by weight of a copolymer resin (weight average molecular weight: 40000, number average molecular weight: 15000), carbon black 5
After dispersing 5 parts by weight of ethyl acetate and 1000 parts by weight of ethyl acetate in a sand mill for 5 hours, 42 parts by weight of a wax ethyl acetate dispersion were added, and the mixture was stirred well until uniform to prepare an oil phase liquid. 60 parts by weight of calcium carbonate and 40 parts by weight of water were dispersed in a ball mill for 10 hours to obtain a calcium carbonate dispersion. 6 parts by weight of this calcium carbonate dispersion and cellogen BS-H
100 parts by weight of a 2% by weight aqueous solution (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was 5,000 rpm by a tabletop colloid mill (manufactured by Nippon Seiki Seisakusho).
m for 5 minutes to prepare an aqueous phase liquid. After adding 50 parts by weight of the oil phase liquid to the aqueous phase liquid and mixing at 8000 rpm for 20 minutes, the organic solvent is removed under reduced pressure in a 25 ° C. water bath. 6
After 100 parts by weight of N hydrochloric acid was added to remove calcium carbonate, the solid was washed with water, dried and classified to obtain a solid toner having an average particle diameter of 7.4 μm. Looking at the SEM photograph, the shape was almost spherical. To check the wax shape in the toner,
When observed with a TEM photograph in the same manner as in Example 1,
The average length (a) of the major axis of the wax was 0.56 μm, the average length (b) of the minor axis of the wax was 0.48 μm, and the shape factor (f = a / b) was 1.17. . In a transmission electron microscope (TEM) photograph of the cross section of the toner, the wax was dispersed inside the toner and was not visible on the surface of the toner particles.
100 parts by weight of toner and 1 part by weight of silica R972 (manufactured by Nippon Aerosil Co., Ltd.) were mixed for 1 minute by a sample mill, and an external silica-added toner was evaluated using A-color 935 (manufactured by Fuji Xerox) without fixing fuser oil. Table 1 shows the results obtained.

(Example 5) 30 parts by weight of paraffin wax (trade name: HNP (high-purity purified paraffin wax), manufactured by Nippon Seiro, melting point: 89 ° C) was added to 250 parts by weight of ethyl acetate, dissolved by heating at 73 ° C, and cooled. 2 obtained by precipitation
A wax crude dispersion at 5 ° C. was obtained in the same manner as in Example 1 except that the temperature of the wax dispersion in the pulverization and / or dispersion region of the DCP mill was 55 ° C. to obtain an ethyl acetate dispersion of wax. The average particle diameter of the wax at this time was 2.0 μm when measured with a laser diffraction / scattering particle size distribution analyzer LA-910 (manufactured by Horiba, Ltd.). Scanning electron microscope (SE)
M), the average length (a) of the major axis of the wax was 2.20 μm, the average length (b) of the minor axis of the wax was 1.44 μm, and the shape factor (f = a / b)
Was 1.53. Hereinafter, the same operation as in Example 1 was performed except that the wax dispersion was different, and as a result, the average particle diameter was 7.3 μm.
m of solid toner was obtained. TE shape of wax in toner
Observation with an M photograph showed that the average length (a) of the major axis of the wax was 2.57 μm, the average length (b) of the minor axis of the wax was 1.59 μm, and the shape factor (f = a / b)
Was 1.62. In a transmission electron microscope (TEM) photograph of the cross section of the toner, the wax is dispersed inside the toner,
It was not visible on the surface of the toner particles.

A-color 935 was prepared by mixing 1 part by weight of silica R972 (manufactured by Nippon Aerosil Co., Ltd.) with 100 parts by weight of the toner in a sample mill for 1 minute and then adding silica.
Table 1 shows the results of image evaluation using (manufactured by Fuji Xerox) without fixing fuser oil.

Comparative Example 1 Styrene-butyl acrylate 80:20 copolymer resin (weight average molecular weight: 4000)
0, number average molecular weight: 15000) 100 parts by weight, C.I.
I. 3 parts by weight of CI Pigment Red 57 and 3 parts by weight of paraffin wax (trade name: HNP (high-purity purified paraffin wax) manufactured by Nippon Seisu, melting point: 89 ° C.) A solid toner of 0.8 μm was obtained. When the shape of the wax in the toner was observed with a TEM photograph, the average length (a) of the major axis of the wax was 2.7.
1 μm, the average length (b) of the minor axis of the wax is 0.91 μm
m and the shape factor (f = a / b) was 2.98. In a transmission electron microscope (TEM) photograph of the cross section of the toner, the wax was partially exposed on the surface of the toner particles. An external silica toner obtained by mixing 1 part by weight of silica R972 (manufactured by Nippon Aerosil) with 100 parts by weight of the toner in a sample mill for 1 minute is used to fix an image without fixing fuser oil using A-color 935 (manufactured by Fuji Xerox). The results of the evaluation are shown in Table 1.

(Comparative Example 2) A comparative example was carried out except that the crude wax dispersion of Example 5 was treated with a Gaulin homogenizer 15MR-8TA (Doei Shoji) at a pressure of 500 kg / cm ² and ^two passes. In the same manner as in 1, a wax dispersion of ethyl acetate was obtained. The temperature of the wax dispersion during the Gaulin homogenizer treatment was 5 ° C. before the treatment and 45 ° C. after the treatment in both the first and second pass.
The average particle diameter of the wax at this time was 0.65 μm as measured with a laser diffraction / scattering particle size distribution analyzer LA-910 (manufactured by Horiba, Ltd.). When the shape of the wax in the wax dispersion was observed with a scanning electron microscope (SEM), the average length (a) of the major axis of the wax was 1.1.
5 μm, average length (b) of the minor axis of the wax is 0.46 μm
m, and the shape factor (f = a / b) was 2.50. Hereinafter, a solid toner having an average particle diameter of 8.1 μm was obtained in the same manner as in Example 1 except that the wax dispersion was different. When the shape of the wax in the toner was observed with a TEM photograph, the average length (a) of the major axis of the wax was 1.22 μm.
m, the average length (b) of the minor axis of the wax was 0.54 μm, and the shape factor (f = a / b) was 2.26. In a transmission electron microscope (TEM) photograph of the cross section of the toner, the wax was partially exposed on the surface of the toner particles.

A-color 935 was obtained by mixing 1 part by weight of silica R972 (manufactured by Nippon Aerosil) with 100 parts by weight of toner with a sample mill for 1 minute.
Table 1 shows the results of image evaluation using (manufactured by Fuji Xerox) without fixing fuser oil.

Comparative Example 3 Same as Example 5 except that the crude wax dispersion of Example 5 was treated using Nanomaker 200 (manufactured by Nanomizer) at a pressure of 500 kg / cm ² and three passes. Thus, a solid toner having an average particle size of 8.5 μm was obtained. The temperature of the wax dispersion during the nano maker treatment was 5 ° C. before the treatment and 48 ° C. after the treatment in any of the first to third passes. The average particle diameter of the wax is 3.28 μm, the average length (a) of the major axis is 3.90 μm, and the average length (b) of the minor axis of the wax is 2.
45 μm, and the shape factor (f = a / b) was 1.59.

Styrene-butyl acrylate 80:20
50 parts by weight of a copolymer resin (weight average molecular weight: 40000, number average molecular weight: 15000) of C.I. I. 6 parts by weight of CI Pigment Yellow 17 and 500 parts by weight of toluene are dispersed in a sand mill for 5 hours.
7.7 parts by weight were added, and the mixture was stirred well until it became uniform to prepare an oil phase liquid. 60 parts by weight of calcium carbonate and 40 parts by weight of water were dispersed in a ball mill for 10 hours to obtain a calcium carbonate dispersion. 6 parts by weight of this calcium carbonate dispersion and a 2% by weight aqueous solution of cellogen BS-H (manufactured by Daiichi Kogyo Seiyaku) 100
5 parts by weight in a desktop colloid mill (Nippon Seiki Seisakusho)
The mixture was mixed at 000 rpm for 5 minutes to prepare an aqueous phase liquid. 50 parts by weight of the oil phase liquid was added to this aqueous phase liquid, and at 8000 rpm,
After mixing for 20 minutes, the organic solvent was removed under reduced pressure in a water bath at 25 ° C. After removing calcium carbonate by adding 100 parts by weight of 6N hydrochloric acid, the particles were washed, dried, and classified to have an average particle diameter of 7.
An 8 μm solid toner was obtained. Looking at the SEM photograph, the shape was almost spherical. The average length (a) of the major axis of the wax in the toner is 3.25 μm, the average length (b) of the minor axis of the wax is 1.31 μm, and the shape factor (f = a /
b) was 2.48. In a transmission electron microscope (TEM) photograph of the cross section of the toner, the wax was dispersed inside the toner and was not visible on the surface of the toner particles.

A silica R972 (manufactured by Nippon Aerosil) was mixed with 1 part by weight of silica R972 (manufactured by Nippon Aerosil) in a sample mill for 1 minute. Table 1 shows the results of image evaluation.

[0042]

[Table 1]

[0043]

As described above, according to the present invention,
The toner has excellent effects such as offset resistance, chargeability, fluidity, fixability, and cycle stability, and has good color developing properties and OHP transparency, and good image quality can be obtained.
At the same time, the shape of the toner could be controlled, spherical particles could be easily formed, and a toner having good transferability and cleaning properties was obtained.

Claims (11)

[Claims] 1. a step of dissolving or dispersing at least a binder resin, a colorant, and a release agent in an organic solvent in which a binder resin is dissolved to prepare an oil phase component; In a toner for electrophotography manufactured by a manufacturing method including a step of granulating by dispersing the release agent in an organic solvent, the release agent is previously dissolved and then precipitated in an organic solvent or suspended in an organic solvent in advance. A toner for electrophotography, which is a dispersion of a release agent obtained by pulverizing and / or dispersing in a medium after being subjected to the treatment. 2. The spherical fine particles of the release agent have an average particle diameter of 0.1.
2. The electrophotographic toner according to claim 1, wherein the toner is spherical fine particles having a shape in a range of from 01 to 1.5 [mu] m and satisfying a shape factor (f) of the following formula (1). F ≦ 1.25 (1) where f = a / b, a is the average length of the major axis of the release agent particles, and b is the minor axis of the release agent particles. Represents the average length.) 3. The spherical fine particles of the release agent have an average particle diameter of 0.3.
2. The electrophotographic toner according to claim 1, wherein the spherical fine particles are in a range of 1 to 0.5 [mu] m and have a shape satisfying a shape factor (f) of the following formula (1). F ≦ 1.25 (1) (where f = a / b, a is the average length of the major axis of the release agent particles, and b is the minor axis of the release agent particles. Represents the average length.) 4. The electrophotographic toner according to claim 1, wherein the binder resin is a polyester resin. 5. The electrophotographic toner according to claim 1, wherein the melting point of the release agent is 120 ° C. or less. 6. The electrophotographic toner according to claim 1, wherein the release agent is contained in an amount of 0.5 to 15 parts by weight based on 100 parts by weight of the binder resin. 7. A step of dissolving or dispersing at least a binder resin, a colorant, and a release agent in an organic solvent for dissolving the binder resin to prepare an oil phase component, and adding the oil phase component to an aqueous medium. In a method for producing an electrophotographic toner including a step of dispersing and granulating in a toner, a release agent to be dispersed in an organic solvent in which the binder resin is dissolved is preliminarily dissolved and then precipitated in an organic solvent. Or a dispersion of a release agent obtained by previously suspending in an organic solvent and then pulverizing and / or dispersing with a medium. 8. The method according to claim 7, wherein the temperature of the dispersion containing at least the release agent and the organic solvent is kept at 40 ° C. or less when the release agent is pulverized and / or dispersed in the medium. A method for producing an electrophotographic toner. 9. The release agent fine particles of the release agent dispersion obtained by pulverizing and / or dispersing in a medium have an average particle size in the range of 0.01 to 1.5 μm and a shape of: The method for producing an electrophotographic toner according to claim 7, wherein the particles are spherical fine particles satisfying a shape factor (f) of the formula (1). F ≦ 1.25 (1) (where f = a / b, a is the average length of the long axis of the release agent particles, and b is the short axis of the release agent particles) Represents the average length.) 10. The method according to claim 7, wherein in the step of pulverizing and / or dispersing the release agent in the medium, 1 to 20 parts by weight of an organic solvent is used per 1 part by weight of the release agent. A method for producing an electrophotographic toner. 11. An image forming method including a step of forming a latent image on an image carrier, a step of developing the latent image using a developer, and a step of transferring a toner image formed by development onto a transfer body An image forming method according to claim 1, wherein the developer contains the toner according to any one of claims 1 to 6.