JP2002182431A - Electrostatic charge image developing black toner, method for producing the same and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make three color colorants uniform in dispersion diameter and dispersed state and to provide an electrostatic charge image developing black toner excellent in blackness and electrostatic chargeability, a method for producing the toner, a developer and an image forming method. SOLUTION: A phthalocyanine pigment, a quinacridone pigment and an azo pigment are used as a blue colorant, a red colorant and a yellow colorant, respectively. The amounts of the yellow colorant and the blue colorant are 20-70 pts.wt. each based on 100 pts.wt. of the red colorant, the weight ratio of the yellow colorant to the blue colorant is 0.75-1.00 and 5-15 pts.wt., in total, of the colorants are added to 100 pts.wt. resin and mixed to obtain the objective electrostatic charge image developing black toner having a dielectric loss of <=50.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a black toner for developing an electrostatic image used for developing an electrostatic latent image formed by an electrophotographic method, an electrostatic recording method or the like with a developer, and a method for producing the same. The present invention relates to a developer for developing an electrostatic image and an image forming method.

[0002]

2. Description of the Related Art Methods for visualizing image information via an electrostatic image, such as electrophotography, are currently used in various fields. Electrophotography includes a charging step, a step of forming an electrostatic charge image on a photoreceptor by exposure, a step of developing an electrostatic latent image with a developer containing toner to form a toner image, and a step of transferring the toner image on a transfer body. The toner image is visualized through a step of transferring the toner image to the toner image and a step of fixing the toner image.

As the developer used here, a two-component developer comprising a toner and a carrier and a one-component developer using a magnetic toner or a non-magnetic toner alone are known.
The toner is usually produced by a kneading and pulverizing method in which a thermoplastic resin is melt-kneaded together with a releasing agent such as a pigment, a charge controlling agent and a wax, and after cooling, finely pulverized and classified. Then, in order to improve the fluidity and the cleaning property as needed, inorganic fine particles and organic fine particles are externally added to the surface of the toner particles. Although these methods can produce excellent toners, they have the following problems.

The shape of the toner obtained by the ordinary kneading and pulverizing method is irregular, and the shape and surface structure of the toner are delicately changed depending on the pulverizability of the material to be used and the conditions of the pulverizing process. It is difficult. In addition, the kneading and pulverization method cannot use a material that is not suitable for kneading and pulverization, so that selection of the material is greatly restricted. Specifically, the resin colorant kneaded material is sufficiently brittle and cannot be used unless it is a material that can be finely pulverized by an economically feasible manufacturing apparatus. On the other hand, if the resin colorant kneaded material is made brittle to satisfy such requirements, fine powder may be generated or the toner shape may be changed due to mechanical shearing force applied to the toner in a developing machine.

In the case of a two-component developer, the fine powder adheres to the surface of the carrier to accelerate the deterioration of the charge of the developer. Or a change in the shape of the toner, resulting in a decrease in developability, which causes deterioration in image quality. In addition, toner containing a large amount of a release agent such as wax
Depending on the combination of a release agent and a thermoplastic resin, exposure of the release agent to the toner surface often becomes a problem. In particular,
In the case of a combination of a resin whose elasticity is increased by a high molecular weight component and which is not easily crushed and a brittle wax such as polyethylene, polyethylene is often exposed on the toner surface. Such toner is advantageous in releasing property at the time of fixing and cleaning property of untransferred toner from the photoreceptor,
The polyethylene on the surface of the toner receives mechanical force in a developing machine and easily migrates to a developing roll, a photoreceptor, and a carrier, and is liable to be contaminated.

Further, if the toner has an irregular shape, sufficient fluidity cannot be ensured even when a fluidity aid is added. Also, the fine particles on the toner surface move to the toner concave portion due to the mechanical shearing force in the developing machine, and the fluidity decreases over time. , Cleaning performance is deteriorated. Further, when the toner collected by cleaning is returned to the developing machine and used again, the image quality is apt to deteriorate. Increasing the amount of the flow aid used to prevent these problems causes problems such as black spots on the photoreceptor and scattering of the aid particles.

In recent years, as a method for intentionally controlling the shape and surface structure of a toner, a method for producing a toner by an emulsion polymerization aggregation method has been proposed (Japanese Patent Application Laid-Open Nos. Sho 63-282752 and Hei 6-250439). ). These are prepared by preparing a resin fine particle dispersion by emulsion polymerization or the like, while preparing a colorant dispersion in which a colorant is dispersed in a solvent, and then mixing them to form aggregated particles corresponding to the toner particle size, This is a method in which the toner is manufactured by heating to fuse and coalesce the aggregated particles. According to this method, the toner particle diameter can be easily reduced, and an extremely excellent toner having a sharp particle size distribution can be obtained.

In recent years, the demand for higher image quality has increased,
Particularly, in order to realize a high-definition image corresponding to the formation of a color image, the toner tends to have a small diameter. However, even if the diameter of the toner is simply reduced while keeping the conventional particle size distribution, problems such as contamination of the carrier and the photoreceptor and toner scattering become remarkable due to the presence of the fine powder side toner, resulting in high image quality and high reliability. Was difficult to achieve at the same time. In order to solve these problems, it is important to sharpen the particle size distribution of the toner and to reduce the particle size. The agglomeration fusion method meets these points and is a very advantageous method.

On the other hand, in recent years, digital full-color copying machines and printers use color image documents of B (blue),
After color separation by each of R (red) and G (green) filters, latent images having a dot diameter of 20 to 70 μm corresponding to the original document are converted into Y (yellow), M (magenta), C (cyan), Bk There is a method of developing using each developer of (black) and utilizing the subtractive color mixing action. This method
It is necessary to transfer a large amount of developer compared to the conventional black and white machine, and it is necessary to correspond to the small dot diameter of the latent image.
The sharpness of the particle size distribution is becoming increasingly important.

In view of the trend toward higher speed and energy saving of these copiers, further low-temperature fixability is required as compared with the conventional method. From these points, attention has been paid to an agglutination coalescence method suitable for producing a toner having a sharp particle size distribution and a small particle diameter. The coagulation and coalescence method is advantageous in that the constituent materials need only be easily dispersible in water using, for example, a surfactant, and there is no further restriction. is there.

Conventionally, as a method for expressing black, a method using a black toner to which black magnetic powder is added, and in the field of a full-color toner, a cyan toner produced by a melt-kneading method.
A method has been put to practical use in which toner of each color of magenta yellow is superimposed on an image, and black is developed as process black by a subtractive color mixing action. However, there has been a problem that the chargeability of the three color toners is subtly changed due to the difference in the colorant, and the blackness is changed even by a slight shift in the dot reproducibility.

There is also a method of producing a black toner by melting and kneading a colorant of each color of cyan, magenta and yellow in a binder resin. However, due to a difference in dispersibility of each colorant, a dispersion in the toner is performed. Since the diameter and the dispersion state are different, it is extremely difficult to develop an appropriate black color, and the pigment may be exposed on the surface and impair the chargeability. Therefore, Japanese Patent Application Laid-Open
In Japanese Patent Application Laid-Open No. 1-194577, when a toner is manufactured by a kneading and pulverizing method, a dispersing agent is applied to a colorant, and the dispersibility of the three colorants is adjusted by adjusting the melt-kneading time and temperature. was suggested. However, in the melt-kneading method, it is difficult to make the dispersion diameter and dispersion state of the three colorants uniform, and the colorants are exposed on the toner surface to reduce the charge of the toner, and the charge distribution becomes broad. This may cause fogging and scattering, and may not provide sufficient blackness, which may lead to increased costs due to the use of dispersing aids and prolonged kneading time, as well as reduced productivity. Was.

[0013]

SUMMARY OF THE INVENTION Therefore, the present invention solves the above-mentioned problems, makes the dispersion diameter and dispersion state of the three colorants uniform, and develops an electrostatic charge image excellent in blackness and chargeability. It is intended to provide a black toner for use, a method for producing the same, a developer, and an image forming method.

[0014]

The present invention has succeeded in solving the above-mentioned problems by employing the following constitution. (1) In a black toner for developing an electrostatic image containing a blue colorant, a red colorant and a yellow colorant, a phthalocyanine pigment is used as a blue colorant, a quinacridone pigment is used as a red colorant, and azo is used as a yellow colorant. Using a system pigment, the yellow colorant and the blue colorant are each 20 to 70 parts by weight with respect to 100 parts by weight of the red colorant, and the weight mixing ratio of the yellow colorant and the blue colorant is 0.75. ~
1.00, wherein the total amount of the colorant is 5 to 15 parts by weight with respect to 100 parts by weight of the resin, and the toner has a dielectric loss factor of 50 or less. Black toner for image development.

(2) Volume average particle size distribution index G of the toner
SDv is 1.30 or less, and the ratio (GSDv / GSDp) between GSDv and the number average particle size distribution index GSDp is 0.95.
The black toner for developing an electrostatic image according to the above (1), characterized in that: (3) The black toner for developing electrostatic images according to (1) or (2), wherein the toner has a surface property index of 2 or less. (4) The toner according to any one of (1) to (3), wherein the shape factor SF1 of the toner is in the range of 100 to 125.
6. A black toner for developing an electrostatic image according to any one of the above.

(5) A resin fine particle dispersion in which resin fine particles of at least 1 μm or less is dispersed, a blue colorant dispersion, a red colorant dispersion and a yellow colorant dispersion are mixed, and the resin fine particles and three-color coloring are mixed. After forming an aggregated particle dispersion by aggregating the agent, the method for producing a black toner for electrostatic image development to form toner particles by fusing and coalescing by heating to a temperature equal to or higher than the glass transition point of the resin fine particles, A phthalocyanine pigment is used as the blue colorant, a quinacridone pigment is used as the red colorant dispersion, and an azo pigment is used as the yellow colorant dispersion. The yellow colorant and the blue color are used for 100 parts by weight of the red colorant. Each colorant is 20 to 70 parts by weight, the weight mixing ratio of the yellow colorant and the blue colorant is 0.75 to 1.00, and the total amount of the colorant is 100 parts by weight of the resin. 5 to 15 parts by weight to prepare the agglomerated particle dispersion, and the toner particles having a loss dielectric constant of 50 or less are obtained through the coalescing step. Manufacturing method of toner.

(6) A dispersion of a release agent is mixed with the dispersion of resin fine particles and the dispersion of colorant of the three colors.
The method for producing a black toner for developing an electrostatic image according to the above (5), wherein the colorant of the color and the release agent are aggregated to form an aggregated particle dispersion. (7) A release agent dispersion and an inorganic compound fine particle dispersion are mixed with the resin fine particle dispersion and the three colorant dispersion, and the resin fine particles, three colorant, release agent and inorganic compound fine particles are mixed. The method for producing a black toner for developing an electrostatic image according to the above (5) or (6), wherein the black toner is aggregated to form an aggregated particle dispersion. (8) After adding the resin fine particle dispersion to the aggregated particle dispersion and attaching the resin fine particles to the surface of the aggregated particles, the adhered particles are heated to a temperature equal to or higher than the glass transition point of the resin fine particles to fuse and coalesce. The method for producing a black toner for developing an electrostatic image according to any one of the above (5) to (7), wherein the toner particles are formed by the following method.

(9) In the developer for developing an electrostatic image containing a carrier and a toner, the toner may be any of the above (1) to (4)
A developer for developing an electrostatic charge image, which is the toner according to any one of the above. (10) The developer for developing an electrostatic image according to (9), wherein the carrier has a resin coating layer.

(11) a step of forming an electrostatic latent image on the electrostatic latent image carrier, a step of developing the electrostatic latent image with a developer on a developer carrier and forming a toner image, Transferring the toner onto a transfer member, fixing the toner image on the transfer member, and cleaning the toner to remove toner remaining on the electrostatic latent image carrier. An image forming method, comprising using the developer for developing an electrostatic image according to (9) or (10).

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have conducted intensive studies to overcome the above-mentioned problems, and as a result, have combined three specific colorants at a specific compounding ratio, added at a specific concentration, and By setting the dielectric loss factor of the toner to 50 or less and the water content of the toner to 0.5% by weight or less, it was possible to provide a black toner for developing an electrostatic image having excellent blackness and chargeability.

The colorant used in the present invention is preferably a phthalocyanine pigment as a blue pigment, a quinacridone pigment as a red pigment, and a yellow pigment as a red pigment in consideration of hue angle, saturation, lightness, weather resistance and dispersibility in a toner. Azo pigments were selected and combined. Examples of the phthalocyanine pigment used in the present invention (B15: 3) include quinacridone pigments such as PR122 and PR202, and azo pigments such as PY74 and PY93. The combination of the above-mentioned pigments is excellent in applicability to the toner of the present invention in a wet production method, and since the coloring power can be easily controlled by the dispersion diameter of the pigment in the toner, the black reproducibility is high.

The mixing ratio of the three color pigments in the present invention is such that the yellow colorant and the blue colorant are 20 to 70 parts by weight with respect to 100 parts by weight of the red colorant, and the weight mixing ratio of the yellow colorant and the blue colorant is 100 parts by weight. In the range of 0.75 to 1.00, and the total amount of these colorants added is 5 to 15 parts by weight with respect to 100 parts by weight of the resin. Black toner can be provided. Here, the weight mixing ratio of the yellow colorant and the blue colorant is represented by (yellow colorant compounding amount) / (blue colorant compounding amount). The preferred blending amount of the yellow colorant and the blue colorant with respect to 100 parts by weight of the red colorant is 25 to 70 parts by weight, and the preferred weight mixing ratio of the yellow colorant and the blue colorant is 0.75 to 1.
The preferred range of the total amount of the colorant is 5 to 15 parts by weight.

When the mixing ratio of the yellow colorant and the blue colorant to 100 parts by weight of the red colorant is less than 20 parts by weight,
If the degree of blackness is not sufficient and exceeds 70 parts by weight, not only the degree of blackness is not obtained but also the colorant is exposed to cause a reduction in chargeability. On the other hand, when the weight ratio of the yellow colorant to the blue colorant is less than 0.75, the color tone becomes reddish and a sufficient blackness cannot be obtained. Also, 1.00
If it exceeds 3, the color tone shifts in the line direction, and a sufficient blackness cannot be obtained. Further, if the total amount of the coloring agent is less than 5 parts by weight, sufficient blackness cannot be obtained, and if it exceeds 15 parts by weight, the controllability of the toner shape deteriorates, and the coloring agent segregates near the toner surface. It is not preferable because it adversely affects the charging property.

These colorants can be dispersed by a known method. For example, a rotary shearing homogenizer, a media type disperser such as a ball mill, a sand mill, an attritor, and a high pressure opposed collision type disperser are preferable. Used. Further, it is preferable that these colorants use a surfactant having polarity and are dispersed in an aqueous system by the homogenizer.

In the black toner of the present invention, it is important that the above three colorants are uniformly dispersed in the binder resin.
The dispersibility of the colorant has a correlation with the dielectric loss factor of the toner. In the present invention, by setting the dielectric loss factor of the toner to 50 or less, uniform dispersibility of the colorant can be confirmed,
Further, by satisfying the mixing ratio of the three colorants and the total amount of the colorants, it is possible to develop a black color, suppress a decrease in toner resistance, maintain good transferability, and reduce toner injection fog. Can be prevented. The preferable range of the dielectric loss factor of the toner is 30 or less.

In the measurement of the dielectric loss factor, the toner powder is formed into a tablet, the water content of the tablet is adjusted to 0.5% by weight or less, and the tablet is placed on a dielectric measurement electrode. Measure under an alternating electric field. Specifically, the toner 5
g into a pellet and an electrode for solid (4
274A), the conductivity was measured by applying a voltage of 5 V with an electric conductivity meter (manufactured by Yokokawa Hewlett-Packard Co.), and the dielectric loss factor was determined by the following equation. Dielectric loss rate = [14.39 / (W × D ² )] × G _x × T _x
× 10 ¹⁰ (where W = 2πf, f: measurement frequency 100 kHz,
D: electrode diameter (cm), G _x : conductivity of sample (s), T
_x: thickness of the sample of pellets represents a (cm)) Incidentally, the moisture content which was as W ₁ and accurately weighed 1g,
When the loss on drying after drying at 110 ° C. for 1 hour is W ₂ , the water content can be determined by the following equation. Water content (% by weight) = [(W ₁ −W ₂ ) / W ₁ ] × 100

The black toner of the present invention has a volume average particle diameter D
_{The 50v} is controlled to ₃ to 9 μm, the volume average particle size distribution index GSDv is controlled to 1.30 or less, and the ratio (GSDv / GSDp) between GSDv and the number average particle size distribution index GSDp is set to 0.3.
By controlling the shape factor SF1 to be 95 or more and the shape factor SF1 in the range of 100 to 125, it is possible to easily obtain a black toner for developing an electrostatic image, which is excellent in blackness, chargeability and safety.

When _D50v is _less than 3 μm, the chargeability becomes insufficient and the developability may be reduced. Also, 9 μm
When it exceeds, the resolution of the image is reduced. GSDv is 1.
If it exceeds 30, the resolution decreases, and (GSDv / GSD
If the value of p) is less than 0.95, the chargeability is reduced and causes image defects such as toner scattering and fogging. Further, when SF1 exceeds 125, the transferability decreases. The preferred range of the volume average particle size D ₅₀ is 3 to 8 μm, and GSDv
Is preferably 1.30 or less, and (GSDv / GSD
The preferred range of p) is 0.96 or more, and the shape factor S
The preferred range of F1 is 115 to 120.

The particle size and the particle size distribution index of the present invention include, for example,
The particle size distribution measured using a measuring instrument such as a Coulter counter (manufactured by Nikkaki Co., Ltd., TAII) or Multisizer II (manufactured by Nikkaki Co., Ltd.) is divided into particle size ranges (channels)
Draw the cumulative distribution of the volume and the number from the smaller diameter side. D _16v is the volume average particle diameter at 16% cumulative, D _16p is the number average particle diameter at 50%, and D _50v is the volume average particle diameter at 50% cumulative. The particle diameter is D _50p , and the volume average particle diameter at which the cumulative value is 84% is D
_84v, a number average particle diameter is defined as D _84p, the volume average particle size distribution index GSDv of ^{_{(D 84v / D 16v) 0.5}} , the volume average particle size distribution index GSDp is calculated from ^{_{(D 84p / D 16p) 0.5}} .

The shape factor SF1 of the toner is obtained as follows. First, an optical microscope image of the toner scattered on the slide glass is taken into a Luzec image analyzer via a video camera, and the maximum length (ML) and the projected area (A) of 100 or more toners are measured (25π ×
ML ² / A) to obtain the toner shape factor SF1
And

The surface property index of the toner of the present invention is preferably 2 or less. If the surface property index exceeds 2, the smoothness of the toner surface may be impaired, the external additive may be buried during external addition, and the chargeability may be reduced. A preferable range of the surface property index is 1.8 or less. The surface property index is obtained as follows. That is, the particle diameter of each channel of the Coulter counter and the number of particles of the particle diameter are measured, each particle is converted into a sphere to obtain a calculated specific surface area, and the measured specific surface area is calculated by the specific surface area calculated from the particle size distribution. The divided surface property index value of the following equation was used. (Calculated value of specific surface area) = 6Σ (n × R ² ) / ｛ρ × Σ (n
× R ³ )｝ (where n is the number of particles in the channel in the Coulter counter, R is the channel particle size in the Coulter counter, and ρ is the toner density) Then, the measured specific surface area is determined by the adsorption method and The surface property index value was determined. (Surface index value) = (Measured specific surface area) / (Calculated specific surface area)

The charge amount of the toner of the present invention is 20 to 40 μm.
A range of C / g is preferred. If the charge amount is less than 20 μC / g, background stain (fogging) tends to occur, and
If it exceeds C / g, the image density tends to decrease. Note that a preferable range of the charge amount is 15 to 35 μC / g. The ratio of the charge amount of the toner of the present invention in summer (high temperature and high humidity) to the charge amount in winter (low temperature and low humidity) is preferably in the range of 0.5 to 1.5. If the ratio is out of this range, the environment dependency of the charging property becomes strong, and the charging stability is lacking, which is not practically preferable.

The black toner for developing an electrostatic image of the present invention can be produced as follows. A resin fine particle dispersion in which resin fine particles of at least 1 micron or less are dispersed, and a colorant dispersion of each of three colors including a phthalocyanine pigment (B15: 3), a quinacridone pigment and an azo pigment, and a mold release agent if necessary The dispersion is added and mixed, and the resin fine particles and the colorant, or the resin fine particles and the colorant and the release agent are aggregated to form an aggregated particle dispersion, and then heated to a temperature equal to or higher than the glass transition point of the resin fine particles. Fusing or coalescing to obtain toner particles, or adding a resin fine particle dispersion to the aggregated particle dispersion and attaching the resin fine particles to the surface of the aggregated particles, and then heating to a temperature equal to or higher than the glass transition point of the resin fine particles. Fused and coalesced to obtain toner particles. By these methods, the three colorants can be uniformly dispersed in the toner particles, so that a black toner for electrostatic image development having the above-mentioned physical properties and excellent in blackness and chargeability can be reliably produced. can do.

The fine resin particles are generally produced by emulsion polymerization or the like. The prepared resin fine particles were prepared in advance with a resin fine particle dispersion using an ionic surfactant, and the blue, red, and yellow colorants dispersed in the ionic surfactant having the opposite polarity were dispersed therein. Two colorant dispersions are prepared and mixed to form hetero-aggregation to form aggregated particles corresponding to the toner diameter, and then heated to a temperature equal to or higher than the glass transition point of the resin fine particles to form aggregated particles. Are coalesced, washed and dried to obtain toner particles.

In the production process, the amounts of the ionic dispersants of the respective polarities may be shifted in advance in the early stage of the aggregation process by mixing and aggregating them at once. Alternatively, a polymer of an inorganic metal salt such as polyaluminum chloride is ionically neutralized to form a matrix in the first stage at a temperature equal to or lower than the glass transition point and stabilize. Add a particle dispersion treated with a dispersant of the polarity and amount to compensate for the deviation in balance, and further, if necessary, heat slightly at a temperature equal to or lower than the glass transition point of the resin contained in the base or additional particles. After stabilizing at a higher temperature, the particles added in the second stage of agglomeration may be coalesced and coalesced by heating to a temperature equal to or higher than the glass transition temperature while the particles added to the surface of the parent aggregated particles remain attached. Further, this aggregation may be repeatedly performed a plurality of times in a stepwise operation.

The polymer used for the resin fine particles used in the present invention is not particularly limited. For example, styrenes such as styrene, parachlorostyrene and α-methylstyrene;
Methyl acrylate, ethyl acrylate, acrylic acid n-
Propyl, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate,
Esters having a vinyl group such as lauryl methacrylate and 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;
Ethylene, propylene, polymers such as monomers such as polyolefins such as butadiene or copolymers obtained by combining two or more thereof, and mixtures thereof, further epoxy resin, polyester resin, polyurethane resin,
Polyamide resins, cellulose resins, polyether resins, etc., non-vinyl condensation resins, or mixtures of these with the vinyl resins, or graft polymers obtained when polymerizing vinyl monomers in the presence of these, etc. Can be mentioned.

In the case of a vinyl-based monomer, a resin fine particle dispersion can be prepared by carrying out emulsion polymerization using an ionic surfactant or the like, and in the case of other resins, it is oily and has a solubility in water. If it dissolves in a relatively low solvent, dissolve the resin into those solvents and disperse the fine particles in water with a disperser such as a homogenizer together with an ionic surfactant or polymer electrolyte in water, and then heat or reduce the pressure Then, the solvent is evaporated to prepare a resin fine particle dispersion. The particle diameter of the obtained resin fine particle dispersion is measured, for example, by using a laser diffraction type particle size distribution analyzer (LA-7).
00 Horiba Ltd.).

In the toner of the present invention, a release agent can be contained in the toner particles in an amount of 5 to 25% by weight. The release agent dispersion is mixed with the resin fine particle dispersion and the colorant dispersion to disperse the release agent in the aggregated particles. Also,
When the release agent dispersion is added to the aggregated particle dispersion and the release agent is adhered to the surface of the aggregated particles, an additional particle dispersion is added thereafter so that the release agent is not exposed to the toner particle surface. This is suitable for securing the chargeability and durability.

The release agent that can be used in the present invention is AS
A substance having a main peak at 50 to 140 ° C. measured according to TMD3418-8 is preferred. If the temperature is lower than 50 ° C., offset tends to occur during fixing. 140
When the temperature exceeds ℃, the fixing temperature becomes high, and the smoothness of the surface of the fixed image cannot be obtained, so that the gloss is unfavorably deteriorated. For the measurement of the main peak of the present invention, for example, DSC-7 manufactured by PerkinElmer is used. The temperature correction of the detection unit of the apparatus uses the melting points of indium and zinc, and the heat quantity correction uses the heat of fusion of indium. For the sample, an aluminum pan was used, an empty pan was set as a control, and the heating rate was 10 ° C.
/ Min.

Specific examples of the release agent used in the present invention include low molecular weight polyolefins such as polyethylene, polypropylene and polybutene, silicones having a softening point upon heating, oleamide, erucamide, ricinoleamide, and the like. Fatty acid amides such as stearic acid amide and the like, carnauba wax, rice wax, candelilla wax, vegetable wax such as wax, jojoba oil, etc., animal wax such as beeswax, montan wax, ozokerite, ceresin, Minerals such as paraffin wax, microcrystalline wax, microcrystalline wax, Fischer-Tropsch wax, petroleum wax, and modified products thereof can be used.

These waxes are dispersed in water together with an ionic surfactant or a polymer electrolyte such as a polymer acid or a polymer base, and are heated to a temperature higher than the melting point and subjected to strong shearing or a pressure discharge type dispersion. It can be micronized by a machine to produce a release agent particle dispersion of 1 μm or less. The particle size of the obtained release agent particle dispersion is measured, for example, using a laser diffraction type particle size distribution analyzer (LA-7).
00 Horiba Ltd.).

The toner of the present invention may contain a charge controlling agent in order to further improve and stabilize the chargeability.
As the charge control agent, various kinds of charge control agents which are usually used such as a dye composed of a quaternary ammonium salt compound, a nigrosine compound, a complex of aluminum, iron, chromium and the like, and a triphenylmethane pigment can be used. It is preferable to use a material that is hardly soluble in water in order to control ionic strength that affects coagulation and stability at the time of aggregation and reduce wastewater contamination.

In the toner of the present invention, inorganic fine particles can be attached to the surface of the toner particles in a wet manner in order to stabilize the charging property. Examples of the inorganic fine particles to be added include silica, alumina, titania, calcium carbonate, magnesium carbonate, and tricalcium phosphate, which are all commonly used as external additives on the toner surface, such as ionic surfactants and polymer acids. Can be used by dispersing in a high molecular weight base.

Further, the toner of the present invention is prepared by drying the toner particles in the same manner as a normal toner for the purpose of imparting fluidity and improving the cleaning property, and then, inorganic particles such as silica, alumina, titania and calcium carbonate, vinyl resin, polyester,
It is also possible to externally add resin particles such as silicone to the surface of toner particles by applying a shearing force in a dry state.

In the production of the toner of the present invention, examples of the surfactant used for the purpose of emulsion polymerization, pigment dispersion, dispersion of fine resin particles, dispersion of a release agent, aggregation thereof, or stabilization thereof include sulfate ester salts. System, sulfonate system, phosphate ester system, soap system, etc., anionic surfactants such as amine salt type, quaternary ammonium salt type, etc. can be used. It is also effective to use a nonionic surfactant such as a glycol type, an alkylphenol ethylene oxide adduct type or a polyhydric alcohol type in combination. As the dispersing means, general means such as a rotary shearing homogenizer, a ball mill having a media, a sand mill, and a dyno mill can be used.

After completion of the aggregation and fusion, desired toner particles are obtained through an optional washing step, solid-liquid separation step, and drying step.
In the washing step, it is preferable to perform sufficient replacement washing with ion-exchanged water from the viewpoint of chargeability. The solid-liquid separation step is not particularly limited, but suction filtration, pressure filtration and the like are preferably used from the viewpoint of productivity. Although the drying step is not particularly limited, freeze drying, flash jet drying, fluidized drying, vibration type fluidized drying and the like are preferably used from the viewpoint of productivity.

[0047]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. (Preparation of resin fine particle dispersion) Styrene (manufactured by Wako Pure Chemical) 325 parts by weight n-butyl acrylate (manufactured by Wako Pure Chemical) 75 parts by weight β-carboxyethyl acrylate (manufactured by Rhodia Nika) 9 parts by weight 1'-10-decanediol Diacrylate (manufactured by Shin-Nakamura Chemical) 1.5 parts by weight Dodecanethiol (manufactured by Wako Pure Chemical) 2.7 parts by weight The above components are mixed and dissolved to prepare 413.2 parts by weight of a raw material solution, and an anionic surfactant ( (Dowfax, manufactured by Rhodia Co., Ltd.) 4 parts by weight dissolved in 550 parts by weight of ion-exchanged water, and the raw material solution was added thereto and dispersed in a flask.
While emulsifying and slowly stirring and mixing for 10 minutes, 50 parts by weight of ion-exchanged water in which 6 parts by weight of ammonium persulfate were dissolved was added, and then the system was sufficiently purged with nitrogen. 70 ° C inside the system by bus
And the emulsion polymerization was continued for 5 hours to obtain an anionic resin fine particle dispersion. The obtained resin fine particles had a center particle size of 196 nm, a solid content of 42%, a glass transition point of 51.5 ° C., and a weight molecular weight Mw of 32,400.

(Preparation of Red Colorant Dispersion) Red pigment (Brilliant Red R122: manufactured by Clariant) 45 parts by weight Ionic surfactant (Neogen RK, manufactured by Daiichi Kogyo Seiyaku) 5 parts by weight Ion-exchanged water 200 parts by weight The above components were mixed and dissolved, and dispersed with a homogenizer (Ultra Turrax manufactured by IKA) for 10 minutes to obtain a red colorant dispersion having a central particle diameter of 121 nm.

(Preparation of Blue Colorant Dispersion) Blue pigment (copper phthalocyanine B15: 3: manufactured by Dainichi Seika) 45 parts by weight Ionic surfactant (Neogen RK, manufactured by Daiichi Kogyo Seiyaku) 5 parts by weight Exchange water 200 parts by weight The above components were mixed and dissolved, and dispersed with a homogenizer (Ultra Turrax manufactured by IKA) for 10 minutes to obtain a blue colorant dispersion having a center particle diameter of 172 nm.

(Preparation of Yellow Colorant Dispersion) Yellow pigment (Hanza Yellow Y74: manufactured by Clariant) 45 parts by weight Ionic surfactant (Neogen RK, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 5 parts by weight Ion-exchanged water 200 parts by weight The above components were mixed and dissolved, and dispersed with a homogenizer (Ultra Turrax manufactured by IKA) for 10 minutes to obtain a yellow colorant dispersion having a central particle diameter of 112 nm.

(Preparation of Release Agent Dispersion) Polyethylene wax (PW725, manufactured by Toyo Petrolite Co., Ltd.) 45 parts by weight Ionic surfactant (Neogen RK, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 5 parts by weight ion-exchanged water 200 Parts by weight The above components were mixed and heated to 130 ° C., and the pressure was 150 kg / c with a Gaulin homogenizer (manufactured by Gorin).
The mixture was dispersed under m ² for 15 minutes and cooled to room temperature to obtain a release agent dispersion having a center particle diameter of 180 nm.

Example 1 Resin fine particle dispersion 80 parts by weight Red colorant dispersion 22.4 parts by weight Blue colorant dispersion 6.4 parts by weight Yellow colorant dispersion 6.4 parts by weight Release agent dispersion 40 parts by weight The above components were thoroughly mixed in an ultra-turrax (IKA T50) in a round stainless steel flask.
Dispersed.

Then, polyaluminum chloride was added to this.
4 parts by weight were added, and the dispersion operation was continued with an Ultra Turrax. While stirring the flask in an oil bath for heating, 49
After heating to 49 ° C. and holding at 49 ° C. for 60 minutes, 31 parts by weight of the resin fine particle dispersion was gradually added. Thereafter, the pH in the system was adjusted to 5.4 with a 0.5 mol / L sodium hydroxide aqueous solution, and then the stainless steel flask was closed, and stirring was continued using a magnetic seal for 9 hours.
Heated to 6 ° C and held for 5 hours.

After completion of the reaction, the reaction mixture was cooled, filtered, washed sufficiently with ion-exchanged water, and then subjected to solid-liquid separation by Nutsche suction filtration. This was further redispersed in 3 liters of ion-exchanged water at 40 ° C., and stirred and washed at 300 rpm for 15 minutes.
This was repeated five more times, and when the pH of the filtrate became 7.01, the electric conductivity became 9.8 μS / cm, and the surface tension became 71.1 Nm, solid-liquid separation was performed by Nutsche suction filtration using No. 5A filter paper. Was. Then, vacuum drying was continued for 12 hours to obtain black toner particles of Example 1.

When the particle size of the toner particles was measured with a Coulter counter, the volume average particle size D _50v was 6.3 μm.
m, volume average particle size distribution index GSDv is 1.21, GSD
v / GSDp was 0.98, and the surface property index was 1.57. The shape factor SF1 of the toner particles obtained from shape observation by Luzex was 118.3, and it was observed that the toner particles were spherical. The colorant concentration of the toner particles was 10.9% by weight, the blending amounts of the blue colorant and the yellow colorant with respect to 100 parts by weight of the red colorant were 29 parts by weight, and the dielectric loss factor of the toner particles was 24. It was 2.

Example 2 In Example 1, the amount of the red colorant dispersion was changed to 13.4 parts by weight, the amount of the blue colorant dispersion was changed to 3.4 parts by weight, and the amount of the yellow colorant dispersion was changed to 3.4 parts by weight. Was changed to 3.4 parts by weight to obtain black toner particles of Example 2 in the same manner as in Example 1. The obtained black toner particles have a volume average particle size D _50v of 6.5 μm, a volume average particle size distribution index GSDv of 1.21, and GSDv / GSD.
p was 0.97, the surface property index was 1.53, and the shape factor SF1 was 118.3, which was spherical. The colorant concentration of the toner particles was 6.8% by weight, the blending amounts of the blue colorant and the yellow colorant with respect to 100 parts by weight of the red colorant were 25 parts by weight, and the dielectric loss factor of the toner particles was 14. It was 7.

Example 3 In Example 1, the compounding amount of the red colorant dispersion was 33.6 parts by weight, the compounding amount of the blue colorant dispersion was 8.6 parts by weight, and the yellow colorant dispersion was Was changed to 8.6 parts by weight in the same manner as in Example 1 to obtain black toner particles of Example 3. The obtained black toner particles have a volume average particle size D _50v of 6.6 μm, a volume average particle size distribution index GSDv of 1.20, and GSDv / GSD.
p was 0.99, the surface property index was 1.93, and the shape factor SF1 was 116.3, which was spherical. The colorant concentration of the toner particles was 14.9% by weight, the blending amounts of the blue colorant and the yellow colorant with respect to 100 parts by weight of the red colorant were 26 parts by weight, and the dielectric loss factor of the toner particles was 42. 6
Met.

Example 4 In Example 1, the amount of the red colorant dispersion was changed to 10.7 parts by weight, the amount of the blue colorant dispersion was changed to 7.1 parts by weight, and the amount of the yellow colorant dispersion was changed to 7.1 parts by weight. Was changed to 5.5 parts by weight in the same manner as in Example 1 to obtain black toner particles of Example 4. The obtained black toner particles have a volume average particle size D _50v of 5.4 μm, a volume average particle size distribution index GSDv of 1.23, and GSDv / GSD.
p was 0.96, the surface property index was 1.65, and the shape factor SF1 was 116.3, which was spherical. The colorant concentration of the toner particles was 7.9% by weight, the blending amounts of the blue colorant and the yellow colorant with respect to 100 parts by weight of the red colorant were 66 parts by weight and 51 parts by weight, and the dielectric loss factor of the toner particles was 1
9.2.

Example 5 In Example 1, the amount of the red colorant dispersion was changed to 7.3 parts by weight, the amount of the blue colorant dispersion was changed to 5.1 parts by weight, and the amount of the yellow colorant dispersion was changed to 5.1 parts by weight. Was changed to 4.7 parts by weight to obtain black toner particles of Example 5 in the same manner as in Example 1. The obtained black toner particles have a volume average particle size D _50v of 6.4 μm, a volume average particle size distribution index GSDv of 1.21, and GSDv / GSDp.
Is 0.98, the surface property index is 1.76, and the shape factor S
F1 was 115.7 and was spherical. The colorant concentration of the toner particles was 7.9% by weight, the blending amounts of the blue colorant and the yellow colorant with respect to 100 parts by weight of the red colorant were 70 parts by weight and 64 parts by weight, and the dielectric loss factor of the toner particles was 18.
It was 2.

[Comparative Example 1] In Example 1, the compounding amount of the red colorant dispersion was 18.5 parts by weight, the compounding amount of the blue colorant dispersion was 15.5 parts by weight, and the yellow colorant dispersion was Was changed to 13.5 parts by weight in the same manner as in Example 1 to obtain toner particles of Comparative Example 1. The obtained toner particles had a volume average particle diameter D _50v of 6.7 μm, a volume average particle size distribution index GSDv of 1.31, GSDv / GSDp of 0.94, a surface property index of 2.34, and a shape factor SF.
1 was 137.2 amorphous. The colorant concentration of the toner particles is 15.5% by weight, the blending amounts of the blue colorant and the yellow colorant with respect to 100 parts by weight of the red colorant are 84 parts by weight and 73 parts by weight, and the dielectric loss factor of the toner particles is 5
4.2.

Comparative Example 2 In Example 1, the amount of the red colorant dispersion was changed to 3.2 parts by weight, the amount of the blue colorant dispersion was changed to 6.2 parts by weight, and the amount of the yellow colorant dispersion was changed to 6.2 parts by weight. Was changed to 1.6 parts by weight in the same manner as in Example 1 to obtain toner particles of Comparative Example 2. The obtained toner particles have a volume average particle size D _50v of 6.7 μm, a volume average particle size distribution index GSDv of 1.21, and a GSDv / GSDp of 0.9.
6, the surface property index is 1.66, and the shape factor SF1 is 1
17.2 spherical shape. The concentration of the colorant in the toner particles was 3.9% by weight, and the blending amounts of the blue colorant and the yellow colorant with respect to 100 parts by weight of the red colorant were 194 parts by weight and 5 parts by weight, respectively.
0 parts by weight, and the dielectric loss factor of the toner particles was 13.9.

Comparative Example 3 Toner particles of Comparative Example 3 were obtained in the same manner as in Example 1, except that the yellow colorant was changed from Y74 to PY180. The obtained toner particles have a volume average particle size D _50v of 6.5 μm, a volume average particle size distribution index GSDv of 1.23, and GSDv / GSDp.
Is 0.97, the surface property index is 1.71, and the shape factor S
F1 was 120.0. Further, the colorant concentration of the toner particles was 10.9% by weight, the blending amounts of the blue colorant and the yellow colorant with respect to 100 parts by weight of the red colorant were both 29 parts by weight, and the dielectric loss factor of the toner particles was 25.9. Met.

Comparative Example 4 Resin solid content obtained in Example 1 400 parts by weight Red pigment (Brilliant Red R122: manufactured by Clariant) 224 parts by weight Blue pigment (copper phthalocyanine B15: 3: manufactured by Dainichi Seika) 64 Parts by weight Yellow pigment (Hanza Yellow Y74: manufactured by Clariant) 64 parts by weight Release agent solid content (wax PW850: manufactured by Toyo Petrolite) 40 parts by weight The above components are melt-kneaded at 200 ° C using a Banbury mixer, and then room temperature. After cooling to a mill (100AFG:
(Manufactured by Hosokawa Micron Corporation) to obtain toner particles of Comparative Example 4.

The volume average particle diameter D of the obtained toner particles is as follows.
_{The 50v} was 7.6 μm, the volume average particle size distribution index GSDv was 1.37, the GSDv / GSDp was 0.89, the surface property index was 2.64, and the shape factor SF1 was 145.3, and was amorphous. The colorant concentration of the toner particles was 10.9.
The weight ratio of the blue colorant and the yellow colorant to 100 parts by weight of the red colorant was 29 parts by weight, and the dielectric loss factor of the toner particles was 92.0.

(Preparation of Developer) To 50 g of the toner particles of Examples 1 to 5 and Comparative Examples 1 to 4, hydrophobic silica (TS
720, manufactured by Cabot Corporation), and the mixture was externally added by mixing with a sample mill. This externally added toner is weighed to a ferrite carrier coated with 1% of polymethyl methacrylate (weight average molecular weight: 50,000, manufactured by Soken Chemical Co., Ltd.) having an average particle diameter of 50 μm so that the toner concentration becomes 5%, and is weighed with a ball mill. Examples 1 to 5 were stirred and mixed for 5 minutes
And the developer of Comparative Examples 1-4 was prepared.

(Fixing property test) Examples 1 to 5 and Comparative Example 1
4 to 4 were applied to a Fuji Xerox A color remodeling machine, the amount of applied toner was adjusted to 4.5 g / m ^{2, an image} was formed at a fixing speed of 180 mm / sec, and the blackness of the fixed image was visually observed. And check toner fog and scattering.
The results are shown in Table 1.

[0067]

[Table 1]

(Evaluation) As is clear from Table 1, all of the developers of Examples 1 to 5 had a sufficient blackness of the fixed image, and neither fogging nor scattering of the toner was observed. On the other hand, since the toner of the developer of Comparative Example 1 has a large blending ratio of the blue pigment and the yellow pigment, the fixed image has a strong blue tint, and the total amount of the coloring agent is as large as 15.5% by weight. The coefficient SF1 also has an irregular shape of 137.2.
Scattering was observed, and a satisfactory image could not be obtained. Since the toner of the developer of Comparative Example 2 contained a very large amount of 193 parts by weight of blue pigment, the blackness of the fixed image was low and a blue-gray image was obtained. The mixing ratio of the three colors of the toner of the developer of Comparative Example 3 was within the range of the present invention.
Was changed from PY180 to PY180, the color developability was lowered, the blackness of the fixed image was low, and the image was a reddish gray image. The fixed image was black because the mixing ratio of the three colors of the toner of the developer of Comparative Example 4 was within the range of the present invention.
When observed carefully, the dispersion state of the three color pigments is uneven, so that various colors such as red, blue, and yellow are observed in black, and the pigment is exposed on the toner surface.
Since the distribution of the charging property was widened, fogging and scattering of the toner were observed.

[0069]

According to the present invention, there is provided a black toner for developing an electrostatic image capable of uniformly dispersing three colorants by adopting the above constitution, and having excellent blackness and chargeability. And a good black fixed image was formed.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shuji Sato 1600 Takematsu, Minamiashigara-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. Inventor Masanobu Ninomiya 1600 Takematsu, Minami Ashigara City, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Noriyuki Mizutani 1600 Takematsu, Minami Ashigara City, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. 1600 F-term in Fuji Xerox Co., Ltd. (Reference) 2H005 AB03 BA06 CA02 CA21 EA01 EA07 FA02

Claims (4)

[Claims] 1. A black toner for developing an electrostatic image, comprising a blue colorant, a red colorant and a yellow colorant, wherein a phthalocyanine pigment is used as a blue colorant, a quinacridone pigment is used as a red colorant, and a yellow colorant is used. An azo pigment is used as the colorant, the yellow colorant and the blue colorant are each 20 to 70 parts by weight with respect to 100 parts by weight of the red colorant, and the weight mixing ratio of the yellow colorant and the blue colorant is 0.1. 75 to 1.00, and 5 to 15 parts by weight of the total amount of the coloring agent added to 100 parts by weight of the resin,
And a black toner for developing an electrostatic image, wherein the toner has a dielectric loss factor of 50 or less. 2. A resin fine particle dispersion in which at least 1 μm or less of resin fine particles are dispersed, a blue colorant dispersion, a red colorant dispersion and a yellow colorant dispersion are mixed, and the resin fine particles and three colorants are mixed. Agglomerating to form an aggregated particle dispersion, heating to a temperature equal to or higher than the glass transition point of the resin fine particles, and fusing and coalescing to form toner particles, the method for producing a black toner for electrostatic image development, A phthalocyanine pigment is used as a blue colorant, a quinacridone pigment is used as the red colorant dispersion, and an azo pigment is used as a yellow colorant dispersion. The yellow colorant and the blue colorant are used in 100 parts by weight of the red colorant. 20 to 70 parts by weight of each agent, the weight mixing ratio of the yellow colorant and the blue colorant is 0.75 to 1.00, and the total amount of the colorant is 100 parts by weight of the resin. A black toner for developing an electrostatic image, wherein the dispersion of the aggregated particles is prepared by mixing the mixture at 〜15 parts by weight and the toner particles having a loss dielectric constant of 50 or less are obtained through the coalescing step. Manufacturing method. 3. An electrostatic charge image developing developer containing a carrier and a toner, wherein the toner is the toner according to claim 1. 4. A step of forming an electrostatic latent image on an electrostatic latent image carrier, a step of developing the electrostatic latent image with a developer on a developer carrier and forming a toner image, A step of transferring onto a transfer member, a step of fixing a toner image on the transfer member, and a cleaning step of removing toner remaining on the electrostatic latent image carrier, wherein the developer is An image forming method comprising using the developer for developing an electrostatic image according to claim 3.