JP2002333739A - Non-magnetic black toner and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a black, non-magnetic toner for electrostatic charge development having a high image density and less contamination such as filming on a photoreceptor. SOLUTION: In a non-magnetic black toner obtained through a process of aggregating at least polymer primary particles and colorant particles into a particle aggregate, the colorant particles are obtained by doping a non-magnetic iron oxide with a metal. A non-magnetic black toner, which is a pigment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-magnetic black toner used in an electrophotographic copying machine and a printer. More specifically, the present invention relates to a non-magnetic black toner which is black, non-magnetic, has a high image density, and has little filming on a photoreceptor.

[0002]

2. Description of the Related Art Electrophotographic methods include a magnetic developing method and a non-magnetic developing method, and accordingly, toners for electrostatic charge development include magnetic toners and non-magnetic toners. 2. Description of the Related Art In recent years, with the spread of color printers and the like, non-magnetic methods have been receiving attention. Among them, carbon black is generally used as a colorant for a non-magnetic black toner, but its handling, tint and the like are not always satisfactory. On the other hand, iron powder is also used as a black colorant, but it has magnetism and cannot be applied to non-magnetic development.
Therefore, a new colorant for non-magnetic black toner has been demanded.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel colorant for non-magnetic black toner which can be substituted for carbon black. It is another object of the present invention to provide a toner using the coloring agent, which has a high image density and has less contamination such as filming on a photoreceptor.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies in view of the above problems, and as a result, have found that a toner having a good image can be obtained as a nonmagnetic toner by using a specific black colorant. The invention has been reached. That is, the gist of the present invention is to provide a non-magnetic black toner obtained through a process of aggregating at least polymer primary particles and colorant particles into a particle aggregate, wherein the colorant particles dope a metal to non-magnetic iron oxide. The non-magnetic black toner is a black pigment obtained. Further, another gist of the present invention is to provide a method for producing a non-magnetic black toner having a step of aggregating at least polymer primary particles and colorant particles to obtain a particle aggregate, wherein the colorant particles are formed on non-magnetic iron oxide. The present invention relates to a method for producing a nonmagnetic black toner, which is a black pigment obtained by doping a metal.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The toner of the present invention contains at least a binder resin and a colorant as constituents thereof,
If necessary, a wax, a charge control agent, resin fine particles, and other additives are included. Further, the toner used in the present invention is produced by aggregating primary polymer particles and colorant particles containing at least a binder resin.

[0006] As the polymer primary particles used in the present invention, any known particles may be used as long as they have a suitable particle size containing a polymer component, but are preferably produced by emulsion polymerization. Is used. If manufactured by emulsion polymerization, the degree of circularity is high and the particle size distribution can be narrowed, so that control of the toner particle size in the aggregation step becomes easy. Hereinafter, the toner produced by the emulsion polymerization / aggregation method, which is a preferred embodiment, will be described in more detail.

When a toner is produced by an emulsion polymerization / aggregation method, it usually has a polymerization step, a mixing step, an aggregation step, an aging step, and a washing / drying step. That is, a colorant, a charge controlling agent, a wax and the like are mixed with a dispersion containing the polymer primary particles obtained by emulsion polymerization, and the primary particles in the dispersion are aggregated to have a volume average particle size of about 3 to 8 μm. Particle aggregates and, if necessary, resin fine particles and the like are adhered thereto, and if necessary, the particle aggregates or the particle aggregates to which the resin fine particles are adhered are fused, and the toner particles thus obtained are washed. Dry to obtain the product toner particles.

Polymer Primary Particles The polymer primary particles used in the emulsion polymerization / aggregation method preferably have a glass transition temperature (Tg) of 40 to 80 ° C.
And the average particle size is usually from 0.02 to 3 μm. The polymer primary particles are obtained by emulsion polymerization of a monomer. In performing the emulsion polymerization, a monomer having a Bronsted acidic group (hereinafter, may be simply referred to as an acidic monomer) or a monomer having a Bronsted basic group (hereinafter, may be simply referred to as a basic monomer), It is preferable that the polymerization be advanced by adding a monomer having neither a Bronsted acidic group nor a Bronsted basic group (hereinafter, may be referred to as another monomer). At this time, the monomers may be added separately, or a plurality of monomers may be mixed in advance and added. Further, the monomer composition can be changed during the addition of the monomer. Further, the monomer may be added as it is, or may be added as an emulsified liquid which is previously mixed and adjusted with water or an emulsifier.
As the emulsifier, one or a combination of two or more of the above surfactants is selected.

The monomer having a Bronsted acidic group used in the present invention includes a monomer having a carboxyl group such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, and cinnamic acid, and a sulfonic acid group such as sulfonated styrene. And monomers having a sulfonamide group such as vinylbenzenesulfonamide.

Examples of the monomer having a Bronsted basic group include aromatic vinyl compounds having an amino group such as aminostyrene, nitrogen-containing heterocycle-containing monomers such as vinylpyridine and vinylpyrrolidone, dimethylaminoethyl acrylate, and diethylamino. (Meth) acrylic acid esters having an amino group such as ethyl methacrylate;

The monomer having an acidic group and the monomer having a basic group may each be present as a salt with a counter ion. The blending ratio of the monomer having a Bronsted acidic group or a Bronsted basic group in the monomer mixture constituting the polymer primary particles is preferably 0.05% by weight or more, more preferably 1% by weight or more. And it is preferably at most 10% by weight, more preferably at most 5% by weight.

Other comonomers include styrene,
Methyl styrene, chlorostyrene, dichlorostyrene,
styrenes such as p-tert-butylstyrene, pn-butylstyrene, pn-nonylstyrene, methyl acrylate, ethyl acrylate, propyl acrylate,
N-butyl acrylate, isobutyl acrylate, hydroxyethyl acrylate, ethyl hexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, hydroxyethyl methacrylate, ethylhexyl methacrylate, (Meth) acrylates, acrylamide, N-propylacrylamide, N, N-
Examples thereof include dimethylacrylamide, N, N-dipropylacrylamide, N, N-dibutylacrylamide, and acrylamide. Among them, styrene, butyl acrylate and the like are particularly preferable.

Further, when a cross-linking resin is used for the polymer primary particles, a polyfunctional monomer having radical polymerizability is used as a cross-linking agent shared with the above-mentioned monomers, for example, divinylbenzene, hexanediol diacrylate, Examples include ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol acrylate, diallyl phthalate, and the like. It is also possible to use a monomer having a reactive group in the pendant group, for example, glycidyl methacrylate, methylolacrylamide, acrolein and the like.

[0014] A radically polymerizable difunctional monomer is preferred, and divinylbenzene and hexanediol diacrylate are more preferred. The blending ratio of such a polyfunctional monomer in the monomer mixture is preferably at least 0.005% by weight, more preferably at least 0.1% by weight, particularly preferably at least 0.3% by weight. Preferably 5% by weight or less, more preferably 3% by weight or less,
It is particularly preferably at most 1% by weight.

These monomers may be used alone or as a mixture. In this case, the polymer has a glass transition temperature of 40.
~ 80 ° C is preferred. Glass transition temperature 80
If the temperature exceeds 100 ° C., the fixing temperature may become too high, or the OHP transparency may deteriorate. On the other hand, if the glass transition temperature of the polymer is lower than 40 ° C., the storage stability of the toner may deteriorate. is there.

The polymerization initiator may be added to the polymerization system at any time before, simultaneously with, or after addition of the monomer.
You may combine these addition methods as needed.
In the emulsion polymerization, a known chain transfer agent can be used if necessary. Specific examples of such a chain transfer agent include t-dodecylmercaptan, 2-mercaptoethanol, diisopropylxanthogen, and Carbon chloride, trichlorobromomethane, and the like. The chain transfer agent may be used alone or in combination of two or more kinds, and is used in an amount of 0 to 5% by weight based on the polymerizable monomer. Emulsion polymerization is
Mix the above monomers with water, in the presence of a polymerization initiator,
The polymerization is carried out, and the polymerization temperature is usually 50 to 150 ° C, preferably 60 to 120 ° C, and more preferably 70 to 100 ° C.

The volume average particle diameter of the polymer primary particles thus obtained is generally in the range of 0.02 μm to 3 μm, preferably 0.05 μm to 3 μm, more preferably 0.1 μm to 3 μm.
μm to 2 μm, particularly preferably 0.1 μm to 1 μm
m. The average particle size can be measured using, for example, UPA. When the particle size is smaller than 0.02 μm, it is difficult to control the agglomeration rate, which is not preferable. Also,
If it is larger than 3 μm, the particle size of the toner obtained by agglomeration tends to be large, which is unsuitable for producing a toner of 3 to 8 μm.

The emulsifier used for the emulsion polymerization includes at least one emulsifier selected from a cationic surfactant, an anionic surfactant and a nonionic surfactant. Specific examples of the cationic surfactant include dodecyl ammonium chloride, dodecyl ammonium bromide, dodecyl trimethyl ammonium bromide, dodecyl pyridinium chloride, dodecyl pyridinium bromide, hexadecyl trimethyl ammonium bromide, and the like. Specific examples of the anionic surfactant include fatty acid soaps such as sodium stearate and sodium dodecanoate, sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, sodium lauryl sulfate and the like. Further, specific examples of the nonionic surfactant include polyoxyethylene dodecyl ether, polyoxyethylene hexadecyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl ether, polyoxyethylene sorbitan monooleate ether, and monodecanoyl. And sucrose.

○ Colorant As the colorant used in the present invention, a black pigment doped with a non-magnetic iron oxide, preferably α-Fe ₂ O ₃ with a metal is used. Normally, non-magnetic iron oxide is reddish brown, so that a black pigment can be obtained by doping a metal. The metal to be doped preferably includes chromium (Cr), manganese (Mn), molybdenum (Mo), and tungsten (W), with manganese being most preferred. Emulsion polymerization /
In the production method based on the agglomeration method, a dispersion of primary polymer particles and colorant particles are mixed to form a mixed dispersion, which is then aggregated into a particle aggregate, but the colorant is an emulsifier (described above). (Surfactant) in the form of an emulsion after emulsification in water. The volume average particle size of the colorant particles is preferably 0.05 to 3 μm, and 0.1 to 2 μm.
m is more preferred. When the colorant fine particles have the above-mentioned preferable volume average particle diameter, the particle diameter can be easily controlled at the time of aggregation, and the distribution of the colorant in the toner is likely to be uniform. Further, when producing the polymer primary particles, the colorant fine particles can be used as seeds. In this case, the volume average particle diameter of the colorant fine particles is preferably 0.05 to 1 μm, and more preferably 0.1 to 0.5 μm. When the colorant fine particles have the above-described preferable volume average particle diameter, the particle diameter of the polymer primary particles can be easily controlled. Further, in addition to the metal-doped nonmagnetic iron oxide described above, a black colorant can be used in combination with the toner of the present invention within a range that does not impair the effects of the present invention. Typically, carbon black is used as a coloring agent that can be used in combination. When carbon black is used in combination, the proportion in the black colorant is preferably 50% by weight or less, more preferably 30% by weight or less. Also,
Since the toner of the present invention is non-magnetic, it has a magnetic Fe
₃ O ₄ is not usually used. The amount of the colorant to be used is generally 1 to 25 parts by weight, preferably 3 to 20 parts by weight, based on 100 parts by weight of the polymer primary particles.

○ Wax It is preferable to add a wax to the toner used in the present invention in order to impart releasability to the fixing roller.
Any wax can be used as long as it has a releasing property. Specifically, olefin waxes such as low molecular weight polyethylene, low molecular weight polypropylene, and copolymerized polyethylene; paraffin wax; ester waxes having a long-chain aliphatic group such as behenyl behenate, montanic acid ester, and stearyl stearate; Vegetable waxes such as castor oil carnauba wax; ketones having a long-chain alkyl group such as distearyl ketone; silicones having an alkyl group; higher fatty acids such as stearic acid; long-chain aliphatic alcohols such as eicosanol; Examples thereof include carboxylic acid esters or partial esters of polyhydric alcohols obtained from polyhydric alcohols and long-chain fatty acids; higher fatty acid amides such as oleic amide and stearic acid amide; low molecular weight polyesters and the like.

In order to improve the fixability of these waxes, the melting point of the wax is preferably 30 ° C. or higher,
0 ° C. or higher is more preferable, and 50 ° C. or higher is particularly preferable.
Further, the temperature is preferably 100 ° C. or lower, more preferably 90 ° C. or lower, and particularly preferably 80 ° C. or lower. If the melting point is too low, the wax is likely to be exposed on the surface after fixing and sticky,
If the melting point is too high, the fixability at low temperatures is poor. Further, as the compound type of the wax, an ester wax obtained from an aliphatic carboxylic acid and a monohydric or polyhydric alcohol is preferable.
Those having 0 to 100 are more preferable, and those having 30 to 60 carbon atoms are particularly preferable.

The above waxes may be used alone or as a mixture. Further, the melting point of the wax compound can be appropriately selected depending on the fixing temperature at which the toner is fixed. The amount of wax used is usually 100 polymer primary particles.
0.1 to 40 parts by weight, preferably 2 to 40 parts by weight,
35 parts by weight, more preferably 5 to 30 parts by weight. In the emulsion polymerization / aggregation method, it is preferable to use a wax that has been dispersed in the presence of an emulsifier (the above-mentioned surfactant) and emulsified to obtain a wax fine particle dispersion.

The wax is present in the agglomeration step. The wax may be present in the coagulation of the wax fine particle dispersion with the polymer primary particles and the colorant particles, and the seed emulsion polymerization of the monomer may be carried out in the presence of the wax fine particle dispersion. In some cases, primary polymer particles containing wax are produced to agglomerate the colorant particles with the primary particles. Of these, in order to uniformly disperse the wax in the toner, it is preferable that the wax fine particle dispersion is present at the time of preparing the above-mentioned polymer primary particles, that is, at the time of polymerizing the monomer.

The average particle size of the wax fine particles is 0.01 μm.
m to 3 μm, more preferably 0.1 to 2 μm
m, especially those having a diameter of 0.3 to 1.5 μm are preferably used. The average particle size is, for example, LA-500 manufactured by Horiba.
Can be measured. When the average particle size of the wax emulsion is larger than 3 μm, it is easy to control the particle size during aggregation, and when the average particle size of the emulsion is smaller than 0.01 μm, a dispersion is prepared. Is difficult.

○ Charge control agent A charge control agent may be added to the toner used in the present invention for imparting charge amount and charge stability. As the charge control agent, a conventionally known compound is used. For example, metal complexes of hydroxycarboxylic acids, metal complexes of azo compounds,
Examples include naphthol compounds, metal compounds of naphthol compounds, nigrosine dyes, quaternary ammonium salts, and mixtures thereof. The addition amount of the charge control agent is preferably in the range of 0.1 to 5 parts by weight based on 100 parts by weight of the binder resin.

In the emulsion polymerization / aggregation method, as a method for incorporating a charge control agent, when obtaining polymer primary particles, the charge control agent is used as a seed simultaneously with wax, or the charge control agent is dissolved or dispersed in a monomer or wax. The primary particles of the charge control agent are aggregated simultaneously with the primary particles of the polymer and the colorant to form a particle aggregate. After that, primary particles of the charge control agent can be added to cause aggregation. In this case, it is preferable that the charge control agent is also dispersed in water using an emulsifier (the above-mentioned surfactant) and used as an emulsion (primary particles of the charge control agent) having an average particle size of 0.01 to 3 μm.

○ Mixing Step In the aggregating step of the production method of the present invention, the above-mentioned particles of the compounding components such as the polymer primary particles, the colorant particles, and, if necessary, the charge controlling agent and the wax are mixed simultaneously or sequentially. Although mixed and dispersed, dispersions of the respective components, that is, a polymer primary particle dispersion, a colorant particle dispersion, a charge control agent dispersion, and a wax fine particle dispersion are prepared beforehand. Are preferably mixed to obtain a mixed dispersion. Further, it is preferable that the wax is contained in the toner by using polymer primary particles encapsulated in the polymer primary particles, that is, polymer primary particles obtained by emulsion polymerization using the wax as a seed. In this case, the polymer primary particles are used. It is possible to use the wax encapsulated in and the wax fine particles not encapsulated in combination, but it is more preferable to use substantially the entire amount of the wax in the form encapsulated in the polymer primary particles. is there.

Agglomeration Step The mixed dispersion of the above particles is aggregated in the aggregation step to form a particle aggregate.
There are 1) a method of heating and 2) a method of adding an electrolyte.

When performing aggregation by heating, the aggregation temperature is, specifically, a temperature range of 5 ° C. to Tg (where Tg is the glass transition temperature of the primary polymer particles) and Tg−10.
C. to Tg-5 C. are preferred. Within the above temperature range, the toner can be aggregated to a preferable toner particle size without using an electrolyte. When performing aggregation by heating,
When the aging step is performed subsequent to the aggregation step, the aggregation step and the aging step are continuously performed, and the boundary may be ambiguous. However, the temperature is maintained at a temperature range of Tg-20 ° C to Tg for at least 30 minutes. If there is a step to perform, this is regarded as an aggregation step.

The coagulation temperature is a predetermined temperature and at least 30
It is preferable that the toner particles have a desired particle size by holding the toner particles in a predetermined amount. The temperature may be raised at a constant rate up to a predetermined temperature, or may be raised stepwise. The holding time is preferably from 30 minutes to 8 hours, more preferably from 1 hour to 4 hours, in the range of Tg-20 ° C to Tg. By doing so, a toner having a small particle size and a sharp particle size distribution can be obtained.

When the electrolyte is added to the mixed dispersion for coagulation, either an organic salt or an inorganic salt may be used, but a monovalent or divalent or higher polyvalent metal salt is preferably used. Can be Specifically, NaCl, KCl,
LiCl, Na ₂ SO ₄ , K ₂ SO ₄ , Li ₂ SO ₄ , MgC
l ₂ , CaCl ₂ , MgSO ₄ , CaSO ₄ , ZnSO ₄ ,
Al ₂ (SO ₄ ) ₃ , Fe ₂ (SO ₄ ) ₃ , CH ₃ COON
a, C ₆ H ₅ SO ₃ Na and the like.

The amount of the electrolyte to be added varies depending on the type of the electrolyte, but is usually 0.05 to 25 parts by weight based on 100 parts by weight of the solid component of the mixed dispersion. Preferably 0.1 to 15 parts by weight, more preferably 0.1 to 10 parts by weight
Parts by weight. When the amount of the electrolyte added is significantly smaller than the above range, the progress of the agglutination reaction is slowed down and the
Problems tend to occur, such as fine powder having a particle size of not more than μm remaining or an average particle size of the obtained particle aggregate being not more than 3 μm. Further, when the amount of the electrolyte added is significantly larger than the above range, the aggregation tends to be rapid and difficult to control, and coarse particles of 25 μm or more are mixed in the obtained particle aggregate, or the shape of the aggregate is distorted. It tends to cause problems such as irregular shapes. In the case of performing aggregation by adding an electrolyte, the aggregation temperature is preferably in the range of 5 ° C. to Tg.

○ Other Compounding Components Next, in the present invention, toner particles are formed by coating (adhering or fixing) resin fine particles on the surface of the particle aggregate after the above-mentioned aggregation treatment, if necessary. preferable. When the above-described charge control agent is added after the aggregation treatment, it is preferable to add the resin fine particles after adding the charge control agent to the dispersion containing the particle aggregate.

The resin fine particles are dispersed in water or a liquid mainly composed of water with an emulsifier (the above-mentioned surfactant) and used as an emulsion. The resin fine particles used for the outermost layer of the toner do not contain wax. Is preferred. As the resin fine particles, preferably, the volume average particle size is from 0.02 to
Those having a size of 3 μm, more preferably 0.05 to 1.5 μm, obtained by polymerizing a monomer similar to the monomer used for the above-mentioned polymer primary particles can be used. When the toner is formed by coating the particle aggregate with resin fine particles, the resin used for the resin fine particles is preferably cross-linked.

Aging Step In the emulsion polymerization / aggregation method, Tg + 20 ° C. is used to increase the stability of the particle aggregate (toner particles) obtained by aggregation.
It is preferable to add a ripening step of causing fusion between aggregated particles in the range of Tg + 80 ° C. (where Tg is the glass transition temperature of the primary polymer particles). In the aging step, it is preferable to maintain the temperature in the above-mentioned temperature range for 1 hour or more. By adding the aging step, the shape of the toner particles can be made nearly spherical, and the shape can be controlled. This aging step is usually performed for 1 hour to 24 hours, preferably 2 hours to 10 hours. Although the particle aggregate before the aging step is considered to be an aggregate due to electrostatic or other physical aggregation of the primary particles, after the aging step, the polymer primary particles constituting the particle aggregate are fused to each other. And
Preferably it is substantially spherical. In addition, according to such a method for producing a toner, various shapes such as a grape type in which primary particles are aggregated, a potato type in which fusion has progressed halfway, a spherical shape in which fusion has further progressed, and the like according to purposes. A toner can be manufactured.

○ Washing / Drying Step The particle aggregate obtained through each of the above steps is subjected to solid-liquid separation according to a known method, and the particle aggregate is recovered, and then, if necessary, washed. Thereafter, by drying, desired toner particles can be obtained. In this manner, a toner having a relatively small volume average particle diameter of 3 to 8 μm can be manufactured. Moreover, the toner thus obtained has a sharp particle size distribution and is suitable as a toner for developing an electrostatic image for achieving high image quality and high speed.

A known external additive may be added to the toner used in the present invention in order to control fluidity and developability.
As the external additive, various kinds of inorganic oxide particles such as silica, alumina, titania and the like (which may be subjected to a hydrophobic treatment if necessary), vinyl polymer particles and the like can be used. The amount of the external additive is preferably in the range of 0.05 to 5 parts by weight based on the toner particles.

The toner used in the present invention can be applied to a two-component developer and a non-magnetic one-component developer. When used as a two-component developer, known carriers such as iron powder-based, ferrite-based, and magnetite-based carriers or the like,
Those having a resin coating on their surface or a magnetic resin carrier can be used.

As the coating resin for the carrier, generally known styrene resins, acrylic resins, styrene acrylic copolymer resins, silicone resins, modified silicone resins, fluorine resins, etc. can be used. It is not limited. The average particle size of the carrier is not particularly limited, but preferably has an average particle size of 10 to 200 μm. These carriers are preferably used in an amount of 5 to 100 parts by weight based on 1 part by weight of the toner.

As a method for measuring the particle size of the toner,
A commercially available particle size measuring apparatus can be used, but typically, a precision particle size distribution measuring apparatus manufactured by Beckman Coulter KK Coulter Counter Multisizer II
Is used. The volume average particle diameter (Dv) of the toner used in the present invention is preferably 3 to 8 μm, and 4 to 8 μm.
8 μm is more preferable, and 4 to 7 μm is particularly preferable. If the volume average particle diameter is too large, it is not suitable for forming a high-resolution image, and if it is too small, handling as a powder becomes difficult.

Further, it is preferable that the toner has a sharp particle size distribution because the chargeability among the individual particles is easily uniform. Specifically, in the image forming method and apparatus of the present invention, the volume average particle diameter (Dv) and the number average particle diameter (D
The relationship with n) is preferably 1.0 ≦ Dv / Dn ≦ 1.3, and the value of Dv / Dn is more preferably 1.25 or less, particularly preferably 1.20 or less. Also,
The lower limit of Dv / Dn is 1, which means that all particle diameters are equal, and it is difficult to manufacture.
It is preferably at least 3, more preferably at least 1.05.

It is preferable that the toner has few fine particles (fine powder). When the number of fine particles is small, the fluidity of the toner is improved, and the colorant, the charge control agent and the like are uniformly distributed, and the chargeability is likely to be uniform. For measuring fine particles, for example, a flow particle image analyzer FPIA-2000 manufactured by Sysmex Corporation is preferably used. In the present invention, 0.6 μm to 2.0 μm by a flow type particle image analyzer.
It is preferable to use a toner whose measured value (number) of 12 μm particles is 15% or less of the total number of particles. This means that the fine particles are less than a certain amount,
The number of particles of μm to 2.12 μm is more preferably 10% or less, particularly preferably 5% or less. Further, there is no particular lower limit for the fine particles, and it is most preferable that they are not present at all.

Further, the shape of the toner is preferably as close to spherical as possible. Specifically, as a method of quantifying the shape of the toner, the toner is measured with a flow particle image analyzer FPIA-2000 manufactured by Sysmex Corporation,
When the circularity corresponding to the cumulative particle size value at 50% of the value obtained from the following equation is defined as 50% circularity, 50% circularity is obtained.
Those having a circularity in the range of 0.9 to 1 are preferred. Circularity = Perimeter of a circle with the same area as the projected area of the particle / Perimeter of the projected image

The 50% circularity of the toner indicates the degree of unevenness of the toner particles, and is 1 when the toner is perfectly spherical. As the surface shape becomes more complicated, the value of the circularity decreases. As the shape becomes closer to a sphere, the localization of the charge amount in the solid particles is less likely to occur, and the developability tends to be uniform. Accordingly, 50% of the toner is more preferably 0.92 or more, and 0.9% or more.
Particularly preferred is 5 or more. Further, since it is difficult to produce a perfect sphere in production, it is preferably 0.995 or less, more preferably 0.99 or less.

[0045]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the present invention. In the following,
“Parts” represents “parts by weight”. [Production Example a of Polymer Primary Particle Dispersion a] Nonionic surfactant (Emulgen 950, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 1.0 part and ammonium persulfate 0, 5 parts dissolved in 100 parts of water,
14 parts of styrene, 6 parts of butyl acrylate, and 0.6 part of acrylic acid were added, and emulsion polymerization was performed at 80 ° C. for 8 hours to obtain a polymer primary particle dispersion (polymer primary particle dispersion a).

[Preparation Example of Colorant Dispersion a] An aqueous solution prepared by dissolving 1.0 part of an anionic surfactant (Neogen SC: sodium dodecylbenzenesulfonate) in 50 parts of water was used to prepare α-
10 parts of a pigment (HSB-603 manufactured by Toda Kogyo Co., Ltd.) doped with Mn-doped Fe ₂ O ₃ was added and dispersed by a media mill to obtain a colorant dispersion having an average particle diameter of 0.5 μm (colorant dispersion). Liquid a). [Production Example b of Colorant Dispersion Solution] To an aqueous solution in which 1.0 part of an anionic surfactant (Neogen SC) is dissolved in 50 parts of water, 10 parts of magnetic iron oxide (EPT-1000 manufactured by Toda Kogyo Co., Ltd.) is added. The mixture was dispersed by a mill to obtain a colorant dispersion having an average particle diameter of 0.05 μm (colorant dispersion b).

[Preparation Example of Wax Dispersion a] 30 parts of montanic acid wax (BASF wax S, manufactured by BASF) was added to sodium dodecylbenzenesulfonate (Neogen S)
C) After dispersing in 0.3 part of water in which 70 parts of dissolved water was dispersed by a disper, a homogenizer (15-M-8 manufactured by Gorin Co.) was used.
Using PA), the dispersion was emulsified at 95 ° C. and 100 kg / cm ² to obtain a wax dispersion (wax dispersion a).

Example 1 Polymer Primary Particle Dispersion a 50
0 parts, colorant dispersion a 25 parts, wax dispersion a 3
After mixing 0 parts and adjusting the pH to 4 with stirring using a disperser and dispersing for 2 hours, the volume average particle diameter was measured by a particle size analyzer of dynamic light scattering method (Microtrac UPA manufactured by Nikkiso Co., Ltd.). 1.5 μm associated particles were obtained. Then, the stirring was changed to a chi-shaped blade, and the mixture was heated to 60 ° C. under stirring, and adjusted to pH 7 with ammonia. The mixture was further heated to 90 ° C. with stirring and kept at this temperature for 2 hours to obtain a particle aggregate. The particle aggregate was cooled, separated, washed with water and dried, and then 1.0% of hydrophobic silica (Aerosil R972 manufactured by Nippon Aerosil Co., Ltd.) was added to the obtained particles using a Henschel mixer and mixed to obtain a toner for development. .
The volume average particle size of this developing toner was 8.2 μm. This developing toner is supplied to a commercially available printer (JX970).
0, manufactured by Sharp Corp.), and a continuous print test was conducted. As a result, a clear black image with low fog and high density was obtained even in the test of 40,000 sheets. Also, no image defect was caused by filming or the like.

Comparative Example 1 A toner was produced in the same manner as in Example 1, except that Colorant Dispersion b was used instead of Colorant Dispersion a. The volume average particle size of this developing toner was 8.1 μm. When evaluation was performed in the same manner as in Example 1 using this developing toner, the result of the print test was a result of obtaining a poor image having a very low image density from the beginning of the test.

[0050]

According to the present invention, it is possible to provide a black, non-magnetic toner having a high image density and little filming on a photoreceptor.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Tomoko Ishikawa 1000 Kamoshita-cho, Aoba-ku, Yokohama-shi, Kanagawa F-term in Yokohama Research Laboratory, Mitsubishi Chemical Corporation 2H005 AA06 AB06 CA14 CB03 EA03 EA05

Claims (8)

[Claims] 1. A non-magnetic black toner obtained through a step of aggregating at least polymer primary particles and colorant particles into a particle aggregate, wherein the colorant particles are obtained by doping a non-magnetic iron oxide with a metal. A non-magnetic black toner, which is a black pigment. 2. The non-magnetic black toner according to claim 1, wherein the non-magnetic iron oxide is α-Fe ₂ O ₃ . 3. The non-magnetic iron oxide-doped metal includes chromium (Cr), manganese (Mn), molybdenum (Mo),
3. The non-magnetic black toner according to claim 1, which is selected from tungsten (W). 4. The non-magnetic black toner according to claim 3, wherein the metal doped with the non-magnetic iron oxide is manganese (Mn). 5. The colorant has a volume average particle size of 0.05 to 3 μm.
The non-magnetic black toner according to claim 1, wherein m is m. 6. The non-magnetic black toner according to claim 1, wherein the volume average particle diameter of the toner is 3 to 8 μm. 7. The non-magnetic black toner according to claim 1, wherein the polymer primary particles are obtained by emulsion polymerization in the presence of a wax having a melting point of 30 to 100 ° C. 8. A method for producing a non-magnetic black toner, comprising a step of aggregating at least polymer primary particles and colorant particles to obtain a particle aggregate, wherein the colorant particles are obtained by doping a non-magnetic iron oxide with a metal. A method for producing a non-magnetic black toner, which is a black pigment obtained.