JP2002189313A - Electrostatic charge image developing toner, method of producing the same, electrostatic charge image developing developer, and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic charge image developing black toner excellent in blackness, electrostatic chargeability and safety, a method for producing the toner, and a developer and an image forming method using the developer. SOLUTION: In the electrostatic charge image developing black toner obtained by dispersing a colorant in a resin, 6-50 wt.% fine particles of a black metallic compound having 40-500 nm median particle diameter and <=30 emu/g magnetic force are contained as the colorant in the toner. The water content of the toner is <=0.5 wt.% and the dielectric loss of the toner is <=50. The manufacturing method of the toner, the developer and the image forming method using the toner are also provided.

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, which is used for developing an electrostatic latent image formed by an electrophotographic method, an electrostatic recording method or the like with a developer, a method of manufacturing the same, The present invention relates to a developer for developing a charge 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 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 a toner image onto a transfer body. Transferring step The toner image is visualized through 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, if necessary, inorganic fine particles and organic fine particles are externally added to the surface of the toner particles in order to improve fluidity and cleaning properties. Although these methods can provide fairly good toners, they have the following problems.

The toner produced by the kneading and pulverizing method has an irregular shape, and the shape and surface structure of the toner are delicately changed depending on the pulverizability of the material used and the conditions of the pulverizing process. Have difficulty. 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. In particular,
The resin colorant kneaded material cannot be used unless it is sufficiently brittle and 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 causes a decrease in developability, which causes a 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. Although such toner is advantageous for releasing property at the time of fixing and cleaning of untransferred toner from the surface of the photoreceptor, the polyethylene on the toner surface is subjected to mechanical force in a developing machine, so that a developing roll or a photoreceptor is , It easily migrates to the carrier and becomes easily contaminated, leading to a reduction in reliability.

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. If the amount of the flow aid used is increased in order to prevent these problems, problems such as generation of black spots on the photoreceptor and scattering of the aid particles occur.

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, and also 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 diameter, and heating. This is a method for producing toner by fusing and coalescing aggregated particles. According to this method, the toner particle size 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, the problem of contamination of the carrier and the photoconductor and scattering of the toner become remarkable due to the presence of the fine powder side toner, and high image quality and high reliability are simultaneously achieved. It was difficult to realize. 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, in digital full-color copying machines and printers, color image
(Red) and G (green) after color separation, latent images having a dot diameter of 20 to 70 μm corresponding to the original document are converted into Y (yellow), M (magenta),
There is a method of developing using C (cyan) and Bk (black) developers and utilizing a subtractive color mixing action. This method requires a large amount of developer to be transferred compared to a conventional black and white machine,
Further, since it is necessary to cope with a small dot diameter of a latent image, uniform chargeability and persistence of toner, toner strength, and sharpness of particle size distribution are becoming more and more 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 emulsion polymerization aggregation method suitable for producing a toner having a sharp particle size distribution and a small particle diameter. Furthermore, the agglutination and coalescence method requires that the constituent materials can be easily dispersed in water using, for example, a surfactant and the like, and there is no further restriction.

[0011] In recent years, the use of chemical substances has been studied due to the growing concern about safety of chemical substances. The field of colorants is no exception, and a more secure black colorant has been studied for carbon black which is generally used as a black colorant. Conventionally, as a method of expressing black, a method using a black toner to which black magnetic powder is added,
In the full color toner field, cyan, magenta,
A method has been put to practical use in which toner of each color of yellow is superimposed to produce black as a process black by a subtractive color mixing action.

For example, Japanese Patent Application Laid-Open No. 6-118696 proposes a method of obtaining a one-component magnetic black toner by adding magnetic powder to a hetero-aggregation toner. However, the toner obtained by this method has a certain degree of blackness, but when a high-speed machine or high image quality is intended, the chargeability cannot be sufficiently controlled, and there is a difficulty in maintaining the chargeability. there were.

The method utilizing the subtractive color mixing function is based on the premise that a latent image is formed and then regularly developed and transferred with three color toners so as to appropriately develop black.
However, since the dispersion diameters and dispersion states of the three colorants in the toner are different, the chargeability of the three color toners is slightly changed, and the blackness is changed by a slight shift in dot reproducibility, so that the stable desired It is extremely difficult to develop and maintain the blackness of.

[0014]

SUMMARY OF THE INVENTION Accordingly, the present invention solves the above-mentioned problems, and provides a black toner for developing an electrostatic charge image having excellent blackness, chargeability and safety, a method for producing the same, a developer, and And an image forming method using the developer.

[0015]

The present invention has succeeded in solving the above-mentioned problems by employing the following constitutions. (1) In a black toner for developing an electrostatic image formed by dispersing a colorant in a resin, the colorant has a magnetic force of 30 Am ² /
A black toner for electrostatic charge development, wherein the toner has a dielectric loss factor of 50 or less using black metal compound fine particles of not more than kg. (2) The black toner for electrostatic image development according to (1), wherein the black metal compound fine particles are at least one selected from the group consisting of black iron hydroxide, black titanium oxide, and hematite. . (3) The black toner for electrostatic charge development according to the above (1) or (2), wherein the colorant has a center particle diameter in a range of 40 to 500 nm. (4) The black toner for electrostatic charge development according to any one of (1) to (3), wherein the colorant is incorporated in the toner in an amount of 6.0 to 50% by weight.

(5) 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 any one of the above (1) to (4), wherein (6) The black toner for developing an electrostatic image according to any one of (1) to (5), wherein a surface property index of the toner is 2 or less. (7) The toner according to any one of (1) to (6), wherein the shape factor SF1 of the toner is in a range of 100 to 135.
6. A black toner for developing an electrostatic image according to any one of the above.

(8) A resin fine particle dispersion in which resin fine particles of at least 1 μm or less is dispersed and a colorant dispersion are mixed, and the resin fine particles and the colorant are aggregated to form an aggregated particle dispersion. In the method for producing a black toner for developing an electrostatic image, which is heated to a temperature higher than the glass transition point of the fine particles to fuse and coalesce to form toner particles, the black metal compound having a magnetic force of 30 Am ² / kg or less as the colorant The method for producing a black toner for developing an electrostatic image according to any one of the above (1) to (7), wherein toner particles having a dielectric loss factor of 50 or less are produced using fine particles.

(9) Mixing a release agent dispersion with the resin fine particle dispersion and the colorant dispersion and aggregating the resin fine particles, the colorant and the release agent to prepare an aggregated particle dispersion. The method for producing a black toner for developing an electrostatic image according to the above (8), which is characterized in that: (10) 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 electrostatic image development according to the above (8) or (9), wherein the toner particles are formed by heating.

(11) In a developer for developing an electrostatic charge image comprising a carrier and a toner, the toner is the black toner for developing an electrostatic charge image according to any one of the above (1) to (7). A developer for developing an electrostatic image, characterized by comprising: (12) The developer for developing an electrostatic image according to (11), wherein the carrier has a resin coating layer.

(13) 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 onto a transfer body, fixing a toner image on the transfer body, and an image forming method including a cleaning step of removing toner remaining on the electrostatic latent image carrier,
An image forming method, wherein the developer for developing an electrostatic image according to (11) or (12) is used as the developer.

[0021]

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 found that a magnetic force of 3
It has been found that a black toner excellent in blackness, chargeability and safety can be provided by using black metal compound fine particles of 0 Am ² / kg or less and setting the dielectric loss factor of the toner to 50 or less. The present inventors have found that a black toner can be produced by an aggregation fusion method, and have completed the present invention. The magnetic force in the present invention refers to a saturation magnetization at a measured magnetic field of 796 kA / m.

When the magnetic force of the black metal compound fine particles of the present invention exceeds 30 Am ² / kg, dispersibility of the black metal compound fine particles in the binder resin is hindered, the black metal compound fine particles are easily aggregated, and the reproducibility of blackness is deteriorated. I do. Further, the magnetic force of the toner is increased, the charging property is broadened, and fogging is likely to occur. In consideration of control and maintainability of the charging property, a preferable range of the magnetic force is 10 Am ² / kg or less, and a more preferable range is 5 Am ² / kg or less.

The center particle diameter of the black metal compound fine particles used in the present invention is preferably in the range of 40 to 500 nm. When the central particle diameter is less than 40 nm, the aggregated toner particles become hard, and the shape controllability of the toner in the fusing step is reduced. When the center particle diameter exceeds 500 nm, the content of the black metal compound in the toner decreases, so that sufficient blackness cannot be obtained.

The content of the fine black metal compound particles in the toner is preferably in the range of 6.0 to 50% by weight. Content is 6.
If the amount is less than 0% by weight, sufficient blackness cannot be obtained. If the amount exceeds 50% by weight, the toner cannot be reliably included in the toner, and a part of the toner is exposed. And, as a result, fogging and scattering.

The preferred range of the center particle size of the black metal compound fine particles is 40 to 300 nm, the preferred range of the content is 15 to 45% by weight, and the preferred range of the magnetic force is 20 emu / g or less. It is. The center particle size of the black metal compound fine particles was measured using a particle size measuring device (Micotruck, manufactured by Honeywell).

The black metal compound fine particles used in the present invention are not particularly limited as long as they have the above-mentioned magnetic force. Among them, black iron hydroxide, black titanium oxide and hematite are used alone or in combination. It is preferable to use it. Note that carbon black, which is a conventional black pigment, has a low resistance of, for example, 10 Ω · cm, whereas the black metal compound fine particles according to the present invention have a resistivity of 1 × 10 ⁶ to 1 × 10 ^8.
Since it has a moderately high resistance value of Ω · cm, it has become possible to provide a black toner that is excellent in controllability and maintainability of chargeability.

The black iron hydroxide used in the present invention is obtained by subjecting an aqueous solution of an iron (II) salt such as ferrous sulfate to an alkali treatment with sodium hydroxide or the like while excluding air, and collecting the precipitated powder. Can be manufactured. The black titanium oxide used in the present invention is known as a black pigment for toner (CMC Co., Nov. 20, 1998, “Functional Pigment Technology and Application Development”, p. 25, “4. Hematite used in the present invention is,
Preference is given to manganese-containing hematite. Manganese-containing hematite is an alkali and heat treatment of ferrous sulfate to generate magnetite particles, and then manganese sulfate is added, and further alkali and heat treatment is performed to form magnetite particles coated with manganese and iron hydroxide. The resulting manganese-containing hematite particles can be produced, filtered, washed with water, dried, and pulverized to obtain a black powder, and then heat-treated to produce manganese-containing hematite particles.

In the black toner of the present invention, it is important to uniformly disperse the black metal compound fine particles in the binder resin. The dispersibility of the black metal compound fine particles 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, the black metal compound fine particles are uniformly dispersed, the color development of black can be ensured, the decrease in toner resistance is suppressed, and the transferability is improved. To prevent toner fogging. The preferable range of the dielectric loss factor of the toner is 30 or less.

In the measurement of the above dielectric loss factor, a 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, and an alternating current up to 100 kHz is set. Measure under an 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 factor = [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 : represents the thickness (cm) of the pellet of the sample) In addition, the water content was accurately measured by weighing 1 g and defined as W ₁ .
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 volume average particle diameter D _50v of the toner of the present invention is:
It is preferably from 2 to 9 μm, more preferably from 3 to 8 μm. When the volume average particle diameter D _50v is _less than 2 μm, the chargeability becomes insufficient and the developability may decrease. When the volume average particle diameter D _50v exceeds 9 μm, the resolution of the image decreases. Further, the volume average particle size distribution index GSDv of the toner of the present invention is preferably 1.30 or less, and the ratio (GSDv / GSDp) of the volume average particle size distribution index GSDv to the number average particle size distribution index GSDp is 0.95 or more. Preferably, there is. When the volume average particle size distribution index GSDv exceeds 1.30, the resolution decreases, and the volume average particle size distribution index GSDv and the number average particle size distribution index G
If the ratio to SDp is less than 0.95, the chargeability is reduced, which causes image defects such as scattering and fog.

The particle size and the particle size distribution index of the toner of the present invention are measured using a measuring instrument such as a Coulter Counter TAII (manufactured by Nikkaki), Multisizer II (manufactured by Nikkaki). For the particle size range (channel) obtained by dividing the particle size distribution, the volume and the number are respectively drawn from the smaller diameter side in a cumulative distribution, and the volume average particle size D _16V , the number average particle size D _16p , and the cumulative 50% are 16% and 16%, respectively. _Are defined as a volume average particle diameter D _50V , a number average particle diameter D _50p , and a volume average particle diameter D _84V and a number average particle diameter D _84p with a cumulative value of 84%. Using these, the volume average particle size distribution index (GSDv) is (D
_84V / D _16V) was obtained from ^0.5, the number average particle size distribution index (GSDp) is calculated from ^{_{(D 84p / D 16p) 0.5}} .

The shape factor SF1 of the toner of the present invention is 100
The range of -135 is preferable. When SF1 exceeds 135, there arises a disadvantage that transferability is reduced. In addition,
The more preferable range of SF1 is 100 to 125. The shape factor SF1 of the toner is obtained as follows. First,
The 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, and (25π × ML ²⁾ / A) was determined and defined as a toner shape factor SF1.

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 more preferable range of the surface property index is 1.8 or less. The surface property index is obtained as follows. The particle size of each channel of the Coulter counter and the number of particles of that particle size were measured, each particle was converted to a sphere, the calculated specific surface area was calculated, and the measured specific surface area was divided by the specific surface area calculated from the particle size distribution. The following surface property index value was used. (Calculated specific surface area) = 6 ＝ (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). Was used to determine the surface property index value. (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 more 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. Outside this range, the dependence of the charge amount on the environment becomes strong, and the stability of the charge is lacking, which is not practically preferable. Note that a more preferable range of the charge amount ratio is 0.7 to 1.3.

The black toner having the above characteristics can be easily manufactured by the following method. This method comprises mixing a resin fine particle dispersion in which at least 1 μm or less of resin fine particles are dispersed, a colorant dispersion and, if necessary, a release agent dispersion, and aggregating the resin fine particles and the colorant to form an aggregated particle dispersion. Is prepared, and then heated to a temperature equal to or higher than the glass transition point of the resin fine particles to fuse and coalesce to obtain a toner. The coloring agent used here has a magnetic force of 30 Am ² as described above.
/ Kg or less of the black metal compound fine particles, the black metal compound fine particles can be uniformly dispersed in the binder resin by the above-described agglutination coalescence method, and the blackness of the toner having a dielectric loss factor of 50 or less, A black toner excellent in chargeability can be easily manufactured.

The above resin fine particle dispersion is generally produced by emulsion polymerization or the like. Using a resin fine particle dispersion dispersed with an ionic surfactant, a black metal compound fine particle dispersion dispersed with an ionic surfactant of the opposite polarity is prepared, and the two are mixed to cause hetero-aggregation. To form agglomerated particles corresponding to the diameter of the toner, and thereafter, the aggregated particles are fused and coalesced by heating to a temperature equal to or higher than the glass transition point of the resin fine particles.

In the production process, the ionic dispersant of each polarity may be preliminarily shifted in balance at the beginning of the agglomeration step, for example, by mixing the inorganic metal salt such as calcium nitrate. Or, using a polymer of an inorganic metal salt such as polyaluminum chloride, ionically neutralizing it, forming a first-stage matrix aggregate at a temperature equal to or lower than the glass transition point of the resin, and stabilizing the resultant. As a second step, a particle dispersion treated with a dispersant having a polarity and an amount to make up for a deviation in balance is added, and if necessary, slightly below the glass transition point of the resin contained in the base or additional particles. After heating and stabilizing at a higher temperature, the resin is heated to a temperature equal to or higher than the glass transition point of the resin to form a second aggregate.
The particles added in the step may be coalesced together while being attached to the surface of the mother aggregated particles. Furthermore, the stepwise operation of the aggregation may be repeated plural times.

The polymer of the resin fine particles used for producing the toner of the present invention is not particularly limited.
Styrenes such as parachlorostyrene and α-methylstyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate , Esters having a vinyl group such as n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate; vinyl nitriles such as acrylonitrile and methacrylonitrile; vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; vinyl methyl Vinyl ketones such as ketone, vinyl ethyl ketone and vinyl isopropenyl ketone;
Polymers composed of monomers such as polyolefins such as ethylene, propylene and butadiene, copolymers obtained by combining two or more of them, and mixtures thereof can be used. In addition, epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, etc., non-vinyl condensation resins,
Alternatively, a mixture of these with the above-mentioned vinyl-based resin, a graft polymer obtained by polymerizing a vinyl-based monomer in the coexistence thereof, or the like can be used.

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 is soluble in a relatively low solvent,
Dispersing the resin into those solvents and dispersing the fine particles in water with a disperser such as a homogenizer together with an ionic surfactant and a polymer electrolyte in water, and then heating or reducing the pressure to evaporate the solvent, thereby dispersing the resin fine particle dispersion. Can be prepared. The particle size of the obtained resin fine particles can be measured by, for example, a laser diffraction type particle size distribution analyzer (LA-700, manufactured by Horiba, Ltd.).

In the toner of the present invention, a releasing agent can be contained in the toner particles in an amount of 5 to 25% by weight. The release agent dispersion may be mixed with the resin fine particle dispersion and the colorant dispersion to contain the release agent in the aggregated particles.
When the release agent dispersion is added to the aggregated particle dispersion and the release agent is attached to the surface of the aggregated particles, an additional particle dispersion is added thereafter so that the release agent is not exposed on the toner surface. It is preferable to ensure charging property and durability.

The release agent usable in the present invention includes 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. Also one
If the temperature exceeds 40 ° C., the fixing temperature becomes high, and the smoothness of the surface of the fixed image cannot be obtained, and the glossiness is impaired. 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 1
The measurement is performed at 0 ° 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, vegetable wax such as carnauba wax, rice wax, candelilla wax, wood wax, jojoba oil, animal wax such as beeswax, montan wax, ozokerite, ceresin, paraffin Minerals such as wax, microcrystalline wax, microcrystalline wax, Fischer-Tropsch wax, petroleum-based wax, and modified products thereof can be used.

These waxes are dispersed in water together with an ionic surfactant and a polymer electrolyte such as a polymer acid or a polymer base. The wax is heated to a temperature higher than the melting point and subjected to strong shearing. 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, manufactured by Horiba, Ltd.).

In the toner of the present invention, a charge control agent can be blended for further improving and stabilizing the chargeability.
As the charge control agent, various commonly used charge control agents such as a quaternary ammonium salt compound, a nigrosine compound, a dye composed of a complex of aluminum, iron, and chromium, and a triphenylmethane pigment can be used. It is preferable to use a material that is hardly soluble in water in order to control the ionic strength that affects the stability of coagulation and fusion at one time and reduce wastewater contamination.

In the toner of the present invention, inorganic fine particles can be attached by a wet method 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 polymers. It can be used by dispersing it in an acid or a polymer 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, calcium carbonate, vinyl resin and 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, resin fine particle dispersion, release agent dispersion, aggregation thereof, or stabilization thereof include sulfate ester salts. , Sulfonate, phosphate, soap and other anionic surfactants, and amine salt and quaternary ammonium salt and other cationic surfactants. It is also effective to use a nonionic surfactant such as an alkylphenol ethylene oxide adduct or a polyhydric alcohol. As a dispersing means,
It is possible to use common products such as a rotary shearing homogenizer and a ball mill, a sand mill, and a dyno mill having a medium.

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 there is no particular limitation on the drying step, freeze drying, flash jet drying, fluidized drying, vibration type fluidized drying and the like are preferably used from the viewpoint of productivity.

[0049]

The present invention will be described in detail with reference to the following Examples, which should not be construed as limiting the present invention. (Preparation of resin fine particles) Styrene (manufactured by Wako Pure Chemical Industries) 325 parts by weight n-butyl acrylate (manufactured by Wako Pure Chemical Industries) 75 parts by weight β-carboxyethyl acrylate (manufactured by Rhodia Nika) 9 parts by weight 1′10 decanediol di Acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.) 1.5 parts by weight Dodecanethiol (manufactured by Wako Pure Chemical Industries, Ltd.) 2.7 parts by weight The above components were mixed and dissolved to prepare 413.2 parts by weight of a raw material solution, and anionic surfactant was prepared. To a solution obtained by dissolving 4 parts by weight of an agent (manufactured by Dowfax, Rhodia) in 550 parts by weight of ion-exchanged water, the above-mentioned raw material solution was added, dispersed and emulsified in a flask, and slowly stirred and mixed for 10 minutes. 50 parts by weight of ion-exchanged water in which 6 parts by weight of ammonium sulfate are dissolved
Parts by weight, and then the inside of the system was sufficiently replaced with nitrogen.
And the emulsion polymerization was continued for 5 hours to obtain an anionic resin fine particle dispersion. The central particle size of the obtained resin fine particles is 196 nm, the solid content is 42%,
Glass transition point is 51.5 ° C., weight average molecular weight Mw 324
00.

(Preparation of manganese-containing hematite) 300 liters of ferrous sulfate having a concentration of 1.30 mol / l was previously prepared in a reactor equipped with a stirrer in 200 liters of water and 60 liters of a 15.5N aqueous sodium hydroxide solution. In addition to this, an aqueous ferrous salt solution containing ferrous hydroxide was produced at a pH value of 13 or more and a temperature of 85 ° C. The ferrous salt aqueous solution containing ferrous hydroxide is heated at a temperature of 90 ° C. for 2 minutes per minute.
70 liters of air were bubbled through for 90 minutes to produce magnetite particles. Next, the above magnetite particles 29.6
500 liters of an aqueous suspension containing 1.3 kg / l and 100 liters of an aqueous solution of ferrous sulfate having a concentration of 1.3 mol / l and 100 liters of an aqueous solution of manganese sulfate containing a concentration of 1.3 mol / l.
Liter (the amount of Mn corresponds to 20 atomic% with respect to Fe and Mn) and an aqueous solution of 11.2N sodium hydroxide 46
Liter (corresponding to the amount to neutralize the amount of added Mn and the amount of added Fe ²⁺ ). Magnetite particles coated with hydroxide were produced. The produced particles were collected by filtration, washed with water, dried and pulverized by a conventional method to obtain a black powder. The black powder was passed through a continuous electric furnace having a ceramic furnace tube,
A manganese-containing hematite was obtained by giving an average residence time of 60 minutes at 0 ° C. The obtained manganese-containing hematite had an average particle diameter of 0.25 μm, and as a result of X-ray fluorescence analysis, the manganese content was 14.8% by weight. As a result of X-ray diffraction, a hematite peak was observed.

(Preparation of Colorant Dispersion (1)) 45 parts by weight of manganese-containing hematite (magnetic force: 0 Am ² / g) 5 parts by weight of ionic surfactant (Neogen RK, Daiichi Kogyo Seiyaku) 50 parts by weight ion-exchanged water Parts by weight The above components were mixed and preliminarily dispersed for 10 minutes with a homogenizer (Ultra Turrax, manufactured by IKA), followed by a counter impact wet pulverizer (Ultimizer, manufactured by Sugino Machine Co., Ltd.).
For 15 minutes at a pressure of 245 Mpa to obtain a colorant dispersion liquid (1). The central particle size of the colorant in the obtained colorant dispersion liquid (1) was 354 nm.

(Preparation of Colorant Dispersion (2)) Black iron hydroxide (manufactured by Orient Chemical Co., Ltd., magnetic force 0 Am ² / g) 45 parts by weight Ionic surfactant (Neogen RK, Daiichi Kogyo Seiyaku) 5 parts by weight 200 parts by weight of ion-exchanged water The above components were mixed and preliminarily dispersed for 10 minutes with a homogenizer (Ultra Turrax, manufactured by IKA), and thereafter, a counter impact wet pulverizer (Ultimizer, manufactured by Sugino Machine Co., Ltd.)
Was used for 15 minutes at a pressure of 245 Mpa to obtain a colorant dispersion liquid (3). The central particle size of the colorant in the obtained colorant dispersion liquid (1) was 122 nm.

(Preparation of Colorant Dispersion (3)) Black titanium oxide (manufactured by Titanium Industry Co., Ltd., magnetic force: 0 Am ² / g) 45 parts by weight Ionic surfactant (Neogen RK, Daiichi Kogyo Seiyaku) 5 parts by weight 50 parts by weight of exchanged water The above components are mixed and pre-dispersed with a homogenizer (Ultra Turrax, manufactured by IKA) for 10 minutes, and then a counter-collision wet pulverizer (Ultimizer, Sugino Machine Co., Ltd.)
For 15 minutes at a pressure of 245 MPa to obtain a colorant dispersion liquid (4). The central particle size of the colorant in the obtained colorant dispersion liquid (1) was 89 nm.

(Preparation of Colorant Dispersion (4)) Ferrite (Mitsui Metals Co., Ltd., magnetic force 78 Am ² / g) 45 parts by weight Ionic surfactant (Neogen RK, Daiichi Kogyo Seiyaku) 5 parts by weight Ion-exchanged water 50 parts by weight The above components were mixed and preliminarily dispersed for 10 minutes with a homogenizer (Ultra Turrax, manufactured by IKA), and thereafter, an opposing collision type wet pulverizer (Ultimizer, manufactured by Sugino Machine Co., Ltd.)
For 15 minutes at a pressure of 245 Mpa to obtain a colorant dispersion liquid (2). The central particle size of the colorant in the obtained colorant dispersion liquid (1) was 257 nm.

(Preparation of Release Agent Dispersion) Polyethylene wax (PW850, manufactured by Toyo Petroleum) 200 parts by weight Ionic surfactant (Neogen RK, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 10 parts by weight Ion-exchanged water 630 parts by weight After heating the above components to 130 ° C., a dispersion treatment was performed for 30 minutes under a pressure of 560 kg / cm ² using a Gaulin homogenizer (manufactured by Gorin). Then 50 ° C
The mixture was cooled to obtain a release agent dispersion. The central particle size of the release agent in the obtained release agent dispersion was 200 nm, and the solid content concentration was 25% by weight.

Example 1 Resin Fine Particle Dispersion 80 parts by weight Colorant Dispersion (1) 45 parts by weight Release Agent Dispersion 36 parts by weight The above components were mixed in a round stainless steel flask by Ultra Turrax (T50, Mix well using IKA)
Dispersed. Next, 0.4 parts by weight of polyaluminum chloride was added to the dispersion, the dispersion operation was continued with an ultra turrax, and the flask was stirred with an oil bath for heating.
Heated to 9 ° C. After maintaining at 49 ° C. for 60 minutes, 31 parts by weight of the resin fine particle dispersion was further slowly added. Then, p in the system is added with 0.5N aqueous sodium hydroxide solution.
After adjusting the H to 5.4, the stainless steel flask was sealed, heated to 96 ° C. with stirring using a magnetic seal, and held for 5 hours.

After completion of the reaction, the reaction mixture was cooled, filtered, and sufficiently washed 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 obtained black toner particles was measured with a Coulter counter, the volume average particle size D _50v was 6.4 μm, and the volume average particle size distribution index GSDv was 1.2.
0, the ratio between the volume average particle size distribution index GSDv and the number average particle size distribution index GSDp was 0.98. Further, the shape factor SF1 of the particles obtained from shape observation by Luzex
Of 115.9 was observed to be spherical. The colorant concentration of the toner was 28.4%, and the surface property index was 1.5.
8. The dielectric loss factor of the toner was 25.

Example 2 The procedure of Example 1 was repeated, except that the amount of the colorant dispersion liquid (1) was changed from 45 parts by weight to 80.5 parts by weight. Toner particles were obtained. The volume average particle diameter D _50v of the obtained black toner particles is 6.7 μm, the volume average particle size distribution index GSDv is 1.24, and the ratio between the volume average particle size distribution index GSDv and the number average particle size distribution index GSDp is 0.96. SF1 is 12
At 9.7 it was potato-like. Colorant concentration of toner is 4
The surface property index was 1.5%, and the dielectric loss ratio of the toner was 48.

Example 3 Black toner particles of Example 3 were obtained in the same manner as in Example 1 except that the colorant dispersion liquid (1) was changed to the colorant dispersion liquid (2). Was. The volume average particle diameter D _50v of the obtained black toner particles is 6.6 μm.
m, volume average particle size distribution index GSDv is 1.25, volume average particle size distribution index GSDv and number average particle size distribution index GSD
The ratio to p was 0.97, and SF1 was 118.3, which was spherical. The colorant concentration of the toner was 28.4%, the surface property index was 1.71, and the dielectric loss factor of the toner was 26.

Example 4 Black toner particles of Example 4 were obtained in the same manner as in Example 1 except that the colorant dispersion liquid (1) was changed to the colorant dispersion liquid (3). Was. The volume average particle diameter D _50v of the obtained black toner particles is 6.6 μm.
m, volume average particle size distribution index GSDv is 1.25, volume average particle size distribution index GSDv and number average particle size distribution index GSD
The ratio to p was 0.98, and SF1 was 118.3, which was spherical. The colorant concentration of the toner was 28.4%, the surface property index was 1.70, and the dielectric loss factor of the toner was 38.

Example 5 The procedure of Example 1 was repeated, except that the amount of the colorant dispersion (1) was changed from 45 parts by weight to 7.6 parts by weight. Toner particles were obtained. Volume average particle diameter D of the obtained black toner particles
_50v is 6.4 μm, the volume average particle size distribution index GSDv is 1.21, the ratio between the volume average particle size distribution index GSDv and the number average particle size distribution index GSDp is 0.96, and SF1 is 11
It was spherical at 9.3. The colorant concentration of the toner is 6.2
%, The surface property index was 1.53, and the dielectric loss factor of the toner was 19.

Comparative Example 1 Black toner particles of Comparative Example 1 were obtained in the same manner as in Example 1 except that the colorant dispersion liquid (1) was changed to the colorant dispersion liquid (4). Was. The volume average particle diameter D _50v of the obtained black toner particles is 6.6 μm.
m, volume average particle size distribution index GSDv is 1.33, volume average particle size distribution index GSDv and number average particle size distribution index GSD
The ratio to p was 0.91, and SF1 was 145.3. The toner has a colorant concentration of 51.2% and a surface property index of 2.2.
3. The dielectric loss factor of the toner was 234.

Comparative Example 2 The black toner particles of Comparative Example 2 were prepared in the same manner as in Example 1 except that the amount of the colorant dispersion liquid (1) was changed from 45 parts by weight to 5 parts by weight. I got Volume average particle diameter D _{50v of the} obtained black toner particles
Is 6.6 μm, and the volume average particle size distribution index GSDv is 1.2.
5. The ratio between the volume average particle size distribution index GSDv and the number average particle size distribution index GSDp was 0.94, and SF1 was 118.3, which was spherical. The colorant concentration of the toner was 4.2%, the surface property index was 1.66, and the dielectric loss factor of the toner was 28.

Comparative Example 3 The black toner particles of Comparative Example 3 were prepared in the same manner as in Example 1 except that the amount of the colorant dispersion liquid (1) was changed from 45 parts by weight to 118 parts by weight. I got Volume average particle diameter D of the obtained black toner particles
_50v is 6.6 μm, the volume average particle size distribution index GSDv is 1.25, the ratio between the volume average particle size distribution index GSDv and the number average particle size distribution index GSDp is 0.93, and SF1 is 11
It was spherical at 8.3. The colorant concentration of the toner is 51.0
%, The surface property index was 1.83, and the dielectric loss factor of the toner was 79.

Comparative Example 4 Resin Solid Content Obtained by Preparing Resin Fine Particle Dispersion 477 parts by weight Manganese-containing hematite 225 parts by weight (magnetic force: 0 Am ² / g, center particle diameter: 200 nm) Polyethylene wax (PW850, Toyo Petroleum Co., Ltd.) 90 parts by weight After the above components were heated to 200 ° C. and melted and kneaded with a Banbury mixer, the mixture was cooled to room temperature, and then pulverized (100AF).
G, manufactured by Hosokawa Micron Corporation) to obtain black toner particles of Comparative Example 4. The volume average particle size D _50v of the obtained black toner particles is 7.3 μm, and the volume average particle size distribution index G is
SDv is 1.37, the ratio between the volume average particle size distribution index GSDv and the number average particle size distribution index GSDp is 0.92, SF1
Was 143.7 and was amorphous. The colorant concentration of the toner was 28.4%, the surface property index was 2.29, and the dielectric loss ratio of the toner was 92.

(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 using a sample mill. These externally added toners were weighed to a ferrite carrier having an average particle diameter of 50 μm coated with 1% of polymethyl methacrylate (molecular weight: 50,000, manufactured by Soken Kagaku Co., Ltd.) so that the toner concentration became 5%, and a ball mill was used for 5 minutes. Stir and mix to prepare Examples 1-5
And the developers of Comparative Examples 1 to 4 were prepared.

(Fixing property test) Examples 1 to 5 and Comparative Example 1
The developer Nos. 4 to 4 are manufactured by Fuji Xerox Co., Ltd.
5 modified machine, adjusting the amount of applied toner to 4.5 g / m ² , setting the fixing speed to 180 mm / sec, outputting images, visually confirming the blackness of the fixed image, and Fogging and scattering were examined, and the results are shown in Table 1.

[0069]

[Table 1]

(Evaluation) In all of the developers of Examples 1 to 5, the blackness of the fixed image was sufficient, no fogging or scattering of toner was observed, and a good image was formed.

On the other hand, in the toner of the developer of Comparative Example 1, since ferrite having a magnetic force of 78 emu / g was used as a colorant, the chargeability was broadened due to the influence of the magnetic force, causing fogging. The colorant concentration was 51.2% by weight.
Therefore, the blackness of the fixed image was sufficient. However, the volume average particle size distribution index GSDv was as high as 1.33, the shape factor SF1 was 145.3, which was amorphous, the surface property index was 2.23, and the dielectric loss factor was 234, which was an extremely large value. , Because the dispersibility of the colorant was reduced,
Fogging and scattering were remarkably observed, and a satisfactory image could not be obtained.

The toner of Comparative Example 2 used the same hematite as the colorant as in Example 1, so that a fixed image could be formed, and no fogging or scattering was observed. Was 4.2% by weight, the fixed image was gray and blackness could not be secured.

The toner of Comparative Example 3 used the same hematite as the colorant as in Example 1, but the colorant concentration was as high as 51.0% by weight, so that the blackness of the fixed image was sufficient. . However, the exposure of the colorant was observed, and the charge control became insufficient. As a result, fogging and scattering were remarkable in the fixed image, and a satisfactory image could not be formed.

The toner of the developer of Comparative Example 4 used the same hematite as the colorant in Example 1 and had a colorant concentration of 2
Although 8.4% by weight was within the range of the present invention, since the toner was manufactured by the melt-kneading method, the blackness of the fixed image was sufficient, but the volume average particle size distribution index GSDv was as high as 1.37. In addition, the shape factor SF1 also showed an irregular shape of 143.7, the surface property index was 2.23, the dielectric loss factor was a large value of 92, the dispersibility of the colorant was reduced, and the exposure of the colorant was low. As a result, fogging and scattering were remarkable in the fixed image due to insufficient charge control, and a satisfactory image could not be formed.

[0075]

According to the present invention, a black toner for developing an electrostatic image, which is excellent in blackness, chargeability and safety, can be provided by adopting the above constitution, and a good black fixed image can be formed. Enabled.

Continued on the front page (72) Inventor Shuji Sato 1600 Takematsu, Minami Ashigara City, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Yasuo Kadokura 1600 Takematsu, Minami Ashigara City, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Ninomiya Masanobu Fuji Xerox Co., Ltd., 1600 Takematsu, Minami Ashigara City, Kanagawa Prefecture (72) Inventor Noriyuki Mizutani 1600 Takematsu, Minami Ashigara City, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Toshiyuki Yano 1600 Takematsu, Minami Ashigara City, Kanagawa Fuji Xerox Corporation F-term (reference) 2H005 AA02 AB03 BA06 CB03 CB07 EA01 EA02 FA02

Claims (5)

[Claims] 1. A black toner for developing an electrostatic image formed by dispersing a colorant in a resin, wherein the colorant has a magnetic force of 3%.
A black toner for electrostatic charge development, wherein fine particles of black metal compound of 0 Am ² / kg or less are used, and the dielectric loss factor of the toner is 50 or less. 2. The black for developing an electrostatic image according to claim 1, wherein the black metal compound fine particles are at least one selected from the group consisting of black iron hydroxide, black titanium oxide and hematite. toner. 3. A resin fine particle dispersion in which resin fine particles of at least 1 μm or less are mixed with a colorant dispersion,
A black toner for electrostatic charge image development in which after aggregating resin fine particles and a colorant to form an aggregated particle dispersion, heating to a temperature equal to or higher than the glass transition point of the resin fine particles to fuse and coalesce to form toner particles The method for producing a black toner for developing an electrostatic charge image according to the method of (1), wherein fine particles of a black metal compound having a magnetic force of 30 Am ² / kg or less are used as the coloring agent, and toner particles having a dielectric loss factor of 50 or less are produced. Method. 4. An electrostatic image developing developer comprising a carrier and a toner, wherein the toner is the black toner for electrostatic image development according to claim 1 or 2. Agent. 5. 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, In the image forming method including a step of transferring onto a transfer body, a step of fixing a toner image on the transfer body, and a cleaning step of removing a toner remaining on the electrostatic latent image carrier, a method as claimed in claim 1, wherein the developer is used. Item 6. An image forming method, comprising using the developer for developing an electrostatic image according to Item 4.