JP2002214826A - Electrostatic charge image developing toner and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic charge image developing toner of superior fluidity, having a uniform electric charge distribution and little environmental dependence, less liable to release an external additive, not causing contamination of carrier and triboelectric charging member, less liable to reduce the quantity of electric charges, when it is left standing and giving a stable image. SOLUTION: The electrostatic charge image developing toner contains hydrophobic titanium dioxide having rutile type titanium dioxide and anatase type titanium dioxide within the same particles and having a treated layer surface- treated with a silane coupling agent as an external additive. The mass ratio between the rutile type titanium dioxide and the anatase type titanium dioxide is in the range of (2:98) to (45:55).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a toner for developing an electrostatic image and an image forming method, and more particularly to a toner for developing an electrostatic latent image to which titanium oxide useful as an external additive is externally added.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand in the market for higher definition and higher image quality of electrostatic images obtained by copying machines and printers. To reduce the particle size of toner or to use polyester resin as binder resin. Attempts have been made to achieve higher image quality by using the same. However, when the particle size of the toner is reduced, the charge amount of the toner increases, the adhesion between the toners increases, and the fluidity decreases. In addition, when a polyester resin is used as the binder resin, it is easily affected by temperature and humidity, and the charge amount becomes too high at low humidity, and the charge amount becomes insufficient at high humidity. There is a problem that it is difficult to obtain a toner having a charged amount.

On the other hand, conventionally, silica, titanium oxide or the like is externally added to a toner used for developing an electrostatic latent image for the purpose of imparting fluidity or improving cleaning properties. Surface treatment has been performed. For example, JP-A-62-113158, JP-A-64-626
No. 67 proposes a technique of externally adding hydrophobic silica and titanium oxide, respectively.

Further, from such a viewpoint, Japanese Patent Laid-Open No.
No. 8633 proposes to use a hydrophobic anatase type titanium oxide treated with a silane coupling agent having a light transmittance of 40% or more for a light wavelength of 400 nm. This hydrophobic anatase-type titanium oxide is treated with a silane coupling agent on the anatase-type titanium oxide calcined at a relatively low temperature of 300 to 500 ° C. so that metatitanic acid obtained by hydrolysis by a sulfuric acid method is not sintered. It was done. Japanese Patent Application Laid-Open No. 10-3177 discloses TiO (O
H) be used resulting titanium compound by the reaction of ₂ and the silane coupling agent is disclosed. This titanium compound is obtained by subjecting metatitanic acid obtained by hydrolysis by a sulfuric acid method to surface treatment while hydrolyzing a silane coupling agent in an aqueous medium.

When anatase type titanium oxide and a titanium compound obtained by these methods are externally added to a toner,
It has the characteristics that the adhesion and dispersibility to the toner are extremely good, the fluidity comparable to that of silica is obtained, the fine particles adhering to the toner are hard to separate, and the spent of the carrier is prevented.

However, the toner to which anatase-type titanium oxide and a titanium compound obtained by these methods are externally added does not adhere to the toner due to collision between the carrier and the toner due to agitation or friction between the toner and the blade or sleeve. However, there is a problem that the toner is gradually buried in the toner and the charging becomes unstable.

On the other hand, Japanese Patent Application Laid-Open No. 6-208241 proposes using ultrafine titanium oxide of rutile type as an external additive of a toner. Since the hydrophobic rutile-type ultrafine titanium oxide described in this publication has a spindle-shaped or plate-like particle structure, there is little change in charge due to burying of titanium oxide attached to the toner by friction inside the toner. However, since the particle diameter was larger than that of anatase type titanium oxide, a toner having good fluidity could not be obtained when externally added to the toner. Further, since rutile-type titanium oxide has poor affinity with the silane coupling agent, uniform coating with the silane coupling agent cannot be obtained, and the toner using the same is easily affected by temperature and humidity, and the charge distribution is uneven. There was a problem that.

From such a viewpoint, Japanese Patent Application Laid-Open No. 2000-12
No. 8534 discloses an externally added titanium oxide which has a uniform charge distribution, shows stable charging characteristics without lowering triboelectric charging characteristics, has good dispersibility, and does not become embedded by friction when used in a toner. For the purpose of providing, there is disclosed a hydrophobic rutile type titanium oxide having a treated layer which has hydrous titanium oxide and / or anatase type titanium oxide and is treated with a silane coupling agent.
Since this hydrophobic rutile-type titanium oxide uses rutile-type titanium oxide as a main component, when it is externally added to a toner, even if it adheres to the toner due to friction, it is not buried in the toner. Since there is no possibility of causing a change in charge due to this, and since it contains hydrated titanium oxide and / or anatase type titanium oxide, it has good affinity with a silane coupling agent, and uniform coating with the silane coupling agent can be obtained. However, it has excellent fluidity, uniform charge distribution, low environmental dependency, little detachment of external additives, does not contaminate the carrier and frictional charging member, and has a small decrease in the amount of charge left on the toner, resulting in stable images. Therefore, further improvement is desired in that it can be obtained.

As described above, the conventional hydrophobized titanium oxide has advantages and disadvantages. When the silane coupling agent is uniformly treated, and the ultrafine titanium oxide having good dispersibility is used for the toner, the above-mentioned points are considered. The emergence of ultrafine titanium dioxide improved by the above is expected.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above circumstances, and has as its object to provide excellent fluidity, uniform charge distribution, low environmental dependency, and little external additive detachment. Another object of the present invention is to provide a toner for developing an electrostatic image, which does not contaminate a carrier or a triboelectric charging member, has a small decrease in the amount of toner left uncharged, and can provide a stable image.

[0011]

[Means for Solving the Problems] A toner for developing an electrostatic charge image containing, as an external additive, hydrophobic titanium oxide having rutile-type titanium oxide and anatase-type titanium oxide in the same particle, and having a treatment layer surface-treated with a silane coupling agent. A toner for developing an electrostatic image, wherein the ratio of the rutile-type titanium oxide to the anatase-type titanium oxide of the hydrophobic titanium oxide is in the range of 2:98 to 45:55 in mass ratio.

The hydrophobic titanium oxide has a primary particle size of 0.0
1 to 0.1 μm and a BET specific surface area of 90 to 2
It is preferably 20 m ² / g. The hydrophobic titanium oxide has a degree of hydrophobicity of 30 to 85% and a carbon amount of 2 to 8%,
According to ESCA surface analysis, the exposure amount of titanium element is 0.01 to
Preferably, it is 5%. It is preferable that the toner for developing an electrostatic image has a ratio of toner particles having no corners of 50% by number or more, and a number variation coefficient in a number particle size distribution of 27% or less. In the toner for developing an electrostatic image, the proportion of toner particles having a shape coefficient in the range of 1.2 to 1.6 is 65% by number or more, and the coefficient of variation of the shape coefficient is 16%.
The following toner particles are preferred. It is preferable that the electrostatic image developing toner is obtained by polymerizing at least a polymerizable monomer in an aqueous medium. The toner for electrostatic image development aggregates at least resin particles in an aqueous medium,
It is preferably obtained by fusion. Composite resin particles obtained by a multi-stage polymerization method wherein the electrostatic image developing toner,
The toner obtained by salting out, aggregating, and fusing the colorant particles preferably contains a release agent in a region other than the outermost layer of the composite resin particles.

2. A toner for developing an electrostatic charge image containing, as an external additive, hydrophobic titanium oxide having rutile-type titanium oxide and anatase-type titanium oxide in the same particle, and having a treatment layer surface-treated with a silane coupling agent. The toner for developing an electrostatic image is characterized in that the ratio of toner particles having no corners is 50% by number or more and the number variation coefficient in the number particle size distribution is 27% or less. toner.

In the electrostatic image developing toner, the ratio of the toner particles having a shape coefficient in the range of 1.2 to 1.6 is 65% by number or more, and the variation coefficient of the shape coefficient is 16% or less. It is preferred that It is preferable that the electrostatic image developing toner is obtained by polymerizing at least a polymerizable monomer in an aqueous medium. It is preferable that the toner for developing an electrostatic image is obtained by aggregating and fusing at least resin particles in an aqueous medium. Composite toner particles obtained by a multi-stage polymerization method, wherein the toner for developing an electrostatic image is salted out, aggregated, and fused with colorant particles.
It is preferable that a release agent is contained in a region other than the outermost layer of the composite resin particles.

When the particle diameter of the toner particles for developing an electrostatic image in the above 1 and 2 is D (μm), the natural logarithm lnD
Is plotted on the abscissa, and the relative frequency (m ₁ ) of toner particles included in the most frequent class in the histogram showing the number-based particle size distribution obtained by dividing the abscissa into a plurality of classes at intervals of 0.23;
It is preferable that the sum (M) of the relative frequency (m ₂ ) of the toner particles included in the class having the second highest frequency after the mode is 70% or more.

3. Forming an electrostatic image on the electrostatic image carrier, developing the electrostatic image with a developer containing an electrostatic image developing toner to form a toner image, and forming the toner image on a transfer member. An image forming method including a step of transferring, wherein the electrostatic image developing toner according to 1 or 2 is used as the electrostatic image developing toner.

First, the hydrophobic titanium oxide will be described. [1] Hydrophobic Titanium Oxide The hydrophobic titanium oxide (also referred to as the hydrophobic titanium oxide of the present invention) externally added to the toner for developing an electrostatic image of the present invention has a specific ratio of rutile-type titanium oxide to anatase-type titanium oxide. Characterized by having a treated layer treated with a silane coupling agent.

In the hydrophobic titanium oxide of the present invention, the mass ratio of rutile-type titanium oxide to anatase-type titanium oxide is in the range of 2:98 to 45:55. If the rutile-type titanium oxide is less than 2% by mass, there is a problem that the environmental dependency of charging becomes excessive. If the rutile-type titanium oxide exceeds 45% by mass, sufficient fluidity and cleaning property cannot be obtained. is there.

The ratio of rutile-type titanium oxide to anatase-type titanium oxide, that is, the mass ratio is determined from the peak intensity corresponding to each lattice constant by X-ray diffraction.

The mass ratio of the rutile-type titanium oxide to the anatase-type titanium oxide is specifically determined by performing X-ray diffraction analysis using Cu as the counter electrode, and obtaining the rutile-type titanium oxide at 27.5 ° from the obtained result. The height of the peak and the height of the anatase type peak at 25.3 ° are determined, and the rutile content is determined by substituting the height of each peak into the following equation.

Rutile content (%) = [(RB) / (A
−B) + (RB)] × 100 R: Rutile-type peak height A: Anatase-type peak height B: Base height determined from a chart The silane coupling agent depends on the degree of hydrophobicity and environment. It is used for improving the fluidity and fluidity, and a water-soluble one can be used. As such a silane coupling agent, a chemical structural formula R _n SiX _4-n (where n is 0 to 3)
R represents a hydrogen atom, an organic group such as an alkyl group and an alkenyl group, and X represents a hydrolyzing group such as a chlorine atom, a methoxy group and an ethoxy group. Can be used, and any type of chlorosilane, alkoxysilane, silazane, and special silylating agent can be used, but alkoxysilane is particularly preferable. Examples of the alkoxysilane include vinyltrimethoxysilane, propyltrimethoxysilane, i-butyltrimethoxysilane, n-butyltrimethoxysilane, n-hexyltrimethoxysilane, n-octyltrimethoxysilane, and n-dodecyltrimethoxy Silane,
Examples thereof include phenyltrimethoxysilane and 3-glycoxypropyltrimethoxysilane, and those having 2 to 10 carbon atoms in the hydrocarbon group are preferable. Among them, i-butyltrimethoxysilane and n-butyltrimethoxysilane are particularly preferred.

The amount of the silane coupling agent to be treated is 10 to 100% by mass relative to 100% by mass of titanium oxide.
And preferably in the range of 20 to 70% by mass. When the treatment amount is 10% by mass or less, not only low hydrophobicity can be obtained, but also strong fixation occurs during drying, resulting in poor dispersion. When the treatment amount is 100% by mass or more, the decrease in specific surface area is reduced. Is large and is not preferred.

The hydrophobic titanium oxide of the present invention has a primary particle size of 0.01 to 0.1 μm and a BET specific surface area of 9 μm.
Preferably 0~220m is ² / g, particularly preferably 120~180m ² / g.

From the viewpoint of obtaining high fluidity of the toner, the primary particle diameter of the titanium oxide is 0.01 to 0.10 μm.
m, particularly preferably 0.15 to 0.60 μm. The titanium oxide of the present invention is preferably porous, has many pores inside the particles, and is preferably in a state where the inside of the pores is treated with a silane coupling agent. Thereby, even in a high humidity environment, since the water vapor is trapped inside the pores, the charge amount does not decrease.

The amount of carbon, which is an index of the amount of the silane coupling agent treated, is preferably 2 to 8%. The amount of carbon is
It is determined from a calibration curve prepared from a reference product in which a silane coupling agent having a known structure and titanium oxide are appropriately mixed by a combustion method type carbon analyzer.

From the viewpoint of improving the uniformity of processing, ESC
It is preferable that the exposure amount of the titanium element is 0.01 to 5% in the A surface analysis. If the content is less than 0.01%, the adhesion between the toner and the titanium oxide decreases, and the separated titanium oxide contaminates the carrier, the triboelectric charging member, or the photoreceptor,
Conversely, if it exceeds 5%, the environmental dependence of charging will be widened.

The titanium oxide of the present invention has a dispersibility of 400 n from the viewpoint of obtaining appropriate fluidity and cleaning properties.
m preferably has a spectral transmittance of 10 to 40%,
Further, 20 to 30% is preferable.

Hereinafter, various methods for measuring the titanium oxide of the present invention will be described. (1) Specific surface area The specific surface area was measured by a BET one-point method using an automatic specific surface area measuring device GEMINI 2375 (manufactured by Shimadzu Corporation). (2) Degree of hydrophobicity 10 mg of hydrophobic titanium oxide fine powder was added to 10 ml of water, and methanol was introduced into the water with a microtube pump at a rate of 2 ml / min with stirring, and methanol concentration at the time when the fine powder started to sediment. And the methanol concentration when completely wetted. (3) Dispersibility 0.02 g of the sample and 200 ml of ethanol are collected in a 500 ml beaker, mixed, and subjected to a dispersion treatment with an ultrasonic disperser for 3 minutes. The dispersion thus obtained is filled in a quartz cell, and the spectral transmittance at 400 nm is read by a spectrophotometer, and this value is defined as the transmittance (%). The higher the value, the better the transparency, the less coarse particles, and the better the dispersibility. (4) Primary Particle Size The particles were magnified 100,000 times with a transmission electron microscope and evaluated by the average value of the Feret diameter of 200 particles.

The surface of the hydrophobic titanium oxide particles of the present invention is
It is preferable to coat one or more of aluminum, silicon, titanium, zirconium and tin with a layer containing an element. That is, it is preferable that the particle surface before the treatment with the silane coupling agent is covered with the layer containing the predetermined element.

The reason why the layer is coated before the silane coupling agent treatment is performed is to adjust the chargeability and the resistance. The treatment amount of the element is preferably 3 to 20% by mass. 3
If the amount is less than 20% by mass, it is difficult to obtain the effect of adjusting the charge.
If it exceeds 0% by mass, coalescence of the particles occurs, which is not preferable.

In the present invention, the surface of the treatment layer treated with the silane coupling agent can be further coated with a coupling agent and / or silicone oil. That is, after treating the silane coupling agent in an aqueous medium,
A silane coupling agent or an organosilicon compound such as silicone oil can be treated in the gas phase to improve hydrophobicity and adjust the charge amount. As the silane coupling agent that can be used at this time, in addition to those described above, fluorosilane, aminosilane, polydimethylsiloxane, methylhydrogenpolysiloxane, and the like can be used.

When the treatment is performed in the gas phase, the treatment amount is 1 to 20% by mass, especially 3 to 1% by mass, based on 100% by mass of the obtained fine powder.
Preferably, the treatment is performed at 5% by mass. When the treatment amount is less than 1% by mass, the effect cannot be obtained, and when the treatment amount exceeds 20% by mass, the specific surface area is undesirably low.

Although the hydrophobic titanium oxide of the present invention can be produced by various methods, it can be typically obtained by the following method. 1) Orthotitanic acid obtained by neutralizing a titanyl sulfate solution or a titanium tetrachloride solution with an alkali is aged at a temperature of 35 to 60 ° C., and then a hydrochloric acid concentration of 10 to 45 g / L, Ti
A method in which hydrolysis is performed at an O ₂ concentration of 40 to 140 g / L and a reaction temperature of 90 ° C. to a boiling point (103 ° C.), followed by neutralization. 2) Anatase-type titanium oxide is added to rutile-type titanium oxide obtained by a known method using a water-soluble titanium compound to form 55-55.
98% by mass coating method.

In the present invention, rutile-type titanium oxide coated with 55 to 98% by mass of anatase-type titanium oxide obtained by the method 1) is particularly preferable. According to this method, rutile-type titanium oxide uniformly coated with anatase-type titanium oxide having good crystallinity can be easily obtained.

Specifically, orthotitanic acid obtained by neutralizing a titanyl sulfate solution or a titanium tetrachloride solution with an alkali at a temperature of 30 ° C. or less is aged at 60 to 95 ° C., and then a TiO ₂ concentration of 40 to 95 is obtained. 140 g / L, preferably 60
The reaction is performed at a temperature of from 90 to 120 g / L, a hydrochloric acid concentration of from 1 to 10 g / L, preferably from 2 to 8 g / L, and a reaction temperature of from 90 ° C to the boiling point (103 ° C), preferably at least 100 ° C. When the aging temperature of orthotitanic acid is lower than 60 ° C., a titanium oxide having a low content of the desired anatase type titanium oxide is obtained, and when the temperature exceeds 95 ° C., the content of the anatase type titanium oxide becomes excessively large, which is not preferable. . When the hydrochloric acid concentration is less than 1 g / L, the content of anatase type titanium oxide is 98% by mass.
If the concentration exceeds 10 g / L, the content of anatase type titanium oxide is less than 55% by mass, which is not preferable.

If the reaction temperature of the desired rutile type titanium oxide containing anatase type titanium oxide is lower than 90 ° C., the reaction time is undesirably long.

In the case of producing titanium oxide coated with 55 to 98% by mass of anatase type titanium oxide by the method 2), it is necessary to perform a coating treatment so that particles do not coalesce at the time of coating. is there. For example, such a titanium oxide is subjected to thermal hydrolysis by adding a titanium sulfate solution, or a method of simultaneously adding an alkali and a titanium sulfate solution while keeping the pH constant under heating, or hydrolyzing. It can be obtained by a coating method using a urea neutralization method.

The titanium oxide is preferably obtained by hydrolyzing a monovalent acidic titanium solution.

Here, the monovalent acidic titanium solution refers to a titanium solution obtained by dissolving titanium tetrachloride or orthotitanic acid with hydrochloric acid or nitric acid. When a monovalent acidic titanium solution was used, when a titanium sulfate solution that is a divalent acidic titanium solution was used, only anatase-type titanium oxide was obtained.
This is because rutile-type titanium oxide cannot be obtained.

As in the case of the hydrophobic ultrafine particle anatase type titanium oxide, when the hydrophobic titanium oxide of the present invention is externally added to a toner, it has a characteristic that the adhesion and dispersibility to the toner are extremely good. In addition, since amorphous titanium oxide is mainly used, high fluidity can be imparted to the toner, unlike flaky anatase type titanium oxide. Therefore, there is an effect that good cleaning properties can be obtained even with a relatively round toner.

That is, since the hydrophobic titanium oxide of the present invention has a surface rendered hydrophobic in the form of ultrafine particles, it has a high degree of hydrophobicity and good dispersibility. Is good.

The addition amount of the hydrophobic titanium oxide obtained in the present invention to the toner is preferably from 0.1 to 3% by mass, more preferably from 0.2 to 1% by mass. If the amount is less than 0.1% by mass, the fluidity of the toner cannot be obtained. If the amount exceeds 3% by mass, free particles from the toner increase and cause contamination of the photoreceptor and the carrier, which is not preferable.

Next, the toner for developing an electrostatic image of the present invention (also referred to as the toner of the present invention) will be described. [2] Toner of the Present Invention Toner Production Method The toner of the present invention can be prepared by a suspension polymerization method or emulsion polymerization of a monomer in a liquid (in an aqueous medium) to which an emulsion of necessary additives is added.
Or by preparing a fine resin particles by mini-emulsion polymerization, adding a charge controllable resin particles, then, an organic solvent, by adding a coagulant such as salts and the like, aggregating the resin particles, by a method of fusing. Can be manufactured. Suspension polymerization method One example of a method for producing the toner of the present invention is to dissolve a charge control resin in a polymerizable monomer, and to add a colorant, a releasing agent as needed, a polymerization initiator, and the like. And the various constituent materials are dissolved or dispersed in the polymerizable monomer using a homogenizer, a sand mill, a sand grinder, an ultrasonic disperser or the like. The polymerizable monomer in which the various constituent materials are dissolved or dispersed is dispersed in an aqueous medium containing a dispersion stabilizer into oil droplets having a desired size as a toner by using a homomixer, a homogenizer, or the like. Thereafter, the stirring mechanism is moved to a reaction device (stirring device), which is a stirring blade described later, and the polymerization reaction is advanced by heating. After completion of the reaction, the toner of the present invention is prepared by removing the dispersion stabilizer, filtering, washing and drying. The “aqueous medium” in the present invention means a medium containing at least 50% by mass of water. Emulsion Polymerization Method As a method for producing the toner of the present invention, a method in which resin particles are prepared by salting out, aggregating, and fusing in an aqueous medium can also be mentioned. Although this method is not particularly limited, for example, the methods described in JP-A-5-265252, JP-A-6-329947 and JP-A-9-15904 can be mentioned. That is, a method of salting out, aggregating, and fusing a plurality of fine particles composed of a resin and a colorant, or dispersed particles of a constituent material such as a resin particle and a colorant, particularly, dispersing these in water using an emulsifier. After that, a coagulant having a critical coagulation concentration or more is added for salting out, and at the same time, the formed polymer itself is heated and fused at a glass transition temperature (Tg) or more to gradually form a fused particle while forming a fused particle. When the desired particle size is reached, a large amount of water is added to stop the particle size growth, and the particle surface is smoothed while heating and stirring to control the shape. The toner of the present invention can be formed by drying by heating. Here, a solvent such as alcohol which is infinitely soluble in water may be added together with the coagulant.

The production process of the toner of the present invention mainly comprises the following processes. 1: Multi-stage polymerization step for obtaining composite resin particles in which the release agent is contained in a region other than the outermost layer (center or intermediate layer) 2: Salting out / fusing the composite resin particles and the colorant particles 3: Salting out / fusing step of obtaining toner particles by filtration: filtering the toner particles from the dispersion system of the toner particles,
A filtration / washing step of removing a surfactant or the like from the toner particles 4: a drying step of drying the washed toner particles 5: a step of adding an external additive to the dried toner particles.

Hereinafter, each step will be described in detail. (Multi-stage polymerization step) The multi-stage polymerization step, on the surface of the resin particles,
This is a step of producing composite resin particles by a multi-stage polymerization method of forming a coating layer composed of a monomer polymer.

In the present invention, it is preferable to employ a multi-stage polymerization method of three-stage polymerization or more from the viewpoints of production stability and crushing strength of the obtained toner.

The two-stage polymerization method and the three-stage polymerization method, which are typical examples of the multi-stage polymerization method, will be described below. <Two-step polymerization method> The two-step polymerization method is a composite resin composed of a central part (nucleus) formed of a high molecular weight resin containing a release agent and an outer layer (shell) formed of a low molecular weight resin. This is a method for producing particles.

More specifically, this method will be described. First, a release agent is dissolved in a monomer L to prepare a monomer solution, and this monomer solution is added to an aqueous medium (for example, an aqueous solution of a surfactant). After oil droplets are dispersed in the system, this system is subjected to polymerization treatment (first stage polymerization).
By doing so, a dispersion of high molecular weight resin particles containing a release agent is prepared.

Next, a polymerization initiator and a monomer L for obtaining a low molecular weight resin are added to the dispersion of the resin particles.
Polymerization treatment of monomer L in the presence of resin particles (second stage polymerization)
Is carried out to form a coating layer made of a low-molecular-weight resin (polymer of monomer L) on the surface of the resin particles. <Three-step polymerization method> The three-step polymerization method comprises a central part (nucleus) formed from a high molecular weight resin, an intermediate layer containing a release agent, and an outer layer (shell) formed from a low molecular weight resin. This is a method for producing composite resin particles.

The method will be described in detail. First, a dispersion of resin particles obtained by a polymerization treatment (first-stage polymerization) according to a conventional method is added to an aqueous medium (for example, an aqueous solution of a surfactant). Along with the addition, the monomer solution obtained by dissolving the release agent in the monomer M in the aqueous medium is dispersed in oil droplets, and then the system is subjected to a polymerization treatment (second stage polymerization).
A coating layer (intermediate layer) made of a resin (polymer of monomer M) containing a release agent is formed on the surface of the resin particles (core particles) to form a composite resin particle (high molecular weight resin-intermediate molecular weight resin). )
A dispersion of is prepared.

Next, a polymerization initiator and a monomer L for obtaining a low molecular weight resin are added to the obtained dispersion of the composite resin particles, and the monomer L is subjected to a polymerization treatment in the presence of the composite resin particles. By performing (third stage polymerization), a coating layer made of a low molecular weight resin (polymer of monomer L) is formed on the surfaces of the composite resin particles. In the above method, by incorporating the second-stage polymerization, the release agent can be finely and uniformly dispersed, which is preferable.

One feature of the method for producing a toner according to the present invention is to polymerize a polymerizable monomer in an aqueous medium. That is, when forming resin particles (core particles) or a coating layer (intermediate layer) containing a release agent, the release agent is dissolved in a monomer, and the resulting monomer solution is oiled in an aqueous medium. In this method, latex particles are obtained by dispersing droplets, adding a polymerization initiator to the system, and performing a polymerization treatment.

The aqueous medium referred to in the present invention is water 50 to 10
A medium comprising 0% by mass and 0 to 50% by mass of a water-soluble organic solvent. Examples of the water-soluble organic solvent include, for example, methanol, ethanol, isopropanol, butanol,
Acetone, methyl ethyl ketone, tetrahydrofuran and the like can be exemplified, and an alcohol-based organic solvent which does not dissolve the obtained resin is preferable.

As a polymerization method suitable for forming a resin particle or a coating layer containing a release agent, a release agent is added to an aqueous medium in which a surfactant having a concentration equal to or lower than the critical micelle concentration is dissolved. The monomer solution dissolved in the monomer is dispersed in oil droplets using mechanical energy to prepare a dispersion, and a water-soluble polymerization initiator is added to the obtained dispersion, and the oil is dispersed in the oil droplets. A method of radical polymerization (hereinafter, referred to as a mini-emulsion method) can be used, and the effect of the present invention can be further exhibited, which is preferable. In the above method, an oil-soluble polymerization initiator may be used instead of or together with the water-soluble polymerization initiator.

According to the miniemulsion method in which oil droplets are formed mechanically, unlike the usual emulsion polymerization method, the release agent dissolved in the oil phase does not detach, and the resin particles or A sufficient amount of release agent can be introduced into the coating layer.

Here, the disperser for dispersing oil droplets by mechanical energy is not particularly limited, and for example, a stirrer “CLEARMIX” (M) equipped with a high-speed rotating rotor. -Technic Co., Ltd.), an ultrasonic disperser, a mechanical homogenizer, a Menton-Gaulin and a pressure homogenizer. In addition, as the dispersed particle diameter, 10
1000 nm, preferably 50 to 1000 nm,
More preferably, it is 30 to 300 nm.

As other polymerization methods for forming the resin particles or the coating layer containing the release agent, known methods such as an emulsion polymerization method, a suspension polymerization method, and a seed polymerization method can be employed. . These polymerization methods can also be employed to obtain resin particles (core particles) or coating layers constituting the composite resin particles, which do not contain a release agent.

The particle size of the composite resin particles obtained in this polymerization step is 10 to 10 as a mass average particle size measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.).
It is preferably in the range of 1000 nm.

Further, the glass transition temperature (T
g) is preferably in the range of 48 to 74 ° C, more preferably 52 to 64 ° C.

The softening point of the composite resin particles is 95 to 140.
It is preferably in the range of ° C. [Salt-out / fusion step] In the salt-out / fusion step, the composite resin particles and the colorant particles obtained by the multi-stage polymerization step are subjected to salt-out / fusion (the salt-out and fusion occur simultaneously). Let it do)
This is a step of obtaining irregular (non-spherical) toner particles.

In the present invention, salting out / fusion refers to simultaneous salting out (aggregation of particles) and fusion (disappearance of interfaces between particles) or simultaneous salting out and fusion. Act. In order to simultaneously carry out the salting-out and the fusion, it is necessary to aggregate the particles (composite resin particles, colorant particles) under a temperature condition equal to or higher than the glass transition temperature (Tg) of the resin constituting the composite resin particles. .

In this salting out / fusion step, together with the composite resin particles and the colorant particles, internal additive particles (fine particles having a number average primary particle diameter of about 10 to 1000 nm) such as a charge controlling agent are salted out / fused. May be. The surface of the colorant particles may be modified, and any conventionally known surface modifier may be used.

The colorant particles are subjected to salting out / fusion treatment in a state of being dispersed in an aqueous medium. The aqueous medium in which the colorant particles are dispersed is preferably an aqueous solution in which a surfactant is dissolved at a concentration equal to or higher than the critical micelle concentration (CMC).

The disperser used for the dispersion treatment of the colorant particles is not particularly limited, but is preferably a stirrer “CLEARMIX (CLEARM) equipped with a high-speed rotating rotor.
MIX) "(manufactured by M Technique Co., Ltd.), an ultrasonic disperser, a pressurized disperser such as a mechanical homogenizer, a Menton-Gaulin, a pressure type homogenizer, and a medium disperser such as a Getzman mill or a diamond fine mill.

In order to carry out salting-out / fusion of the composite resin particles and the colorant particles, a salting-out agent having a critical coagulation concentration or more (aggregating agent) is added to the dispersion in which the composite resin particles and the colorant particles are dispersed. ) And heating the dispersion above the glass transition temperature (Tg) of the composite resin particles.

The temperature range suitable for salting out / fusing is (Tg + 10) to (Tg + 50 ° C.), and particularly preferably (Tg + 15) to (Tg + 40 ° C.). In addition, an organic solvent that is infinitely soluble in water may be added in order to effectively perform fusion. [Filtration / Washing Step] In this filtration / washing step, a filtration treatment for filtering out the toner particles from the dispersion of the toner particles obtained in the above step, and the filtered toner particles (cake-like aggregate) And a washing treatment for removing extraneous matter such as a surfactant and a salting-out agent.

Here, the filtration method is not particularly limited, such as a centrifugal separation method, a reduced pressure filtration method using a Nutsche or the like, a filtration method using a filter press or the like. [Drying Step] This step is a step of drying the washed toner particles.

Examples of the dryer used in this step include a spray dryer, a vacuum freeze dryer, and a reduced pressure dryer. A stationary shelf dryer, a movable shelf dryer, a fluidized bed dryer, a rotary bed dryer, It is preferable to use a type dryer, a stirring type dryer and the like.

The water content of the dried toner particles is preferably 5% by mass or less, more preferably 2% by mass or less.

In the case where the dried toner particles are aggregated by a weak attraction between the particles, the aggregate may be crushed. Here, as the crushing device, a mechanical crushing device such as a jet mill, a Henschel mixer, a coffee mill, and a food processor can be used.

The toner of the present invention forms composite resin particles in the absence of a colorant, and adds a dispersion of the colorant particles to a dispersion of the composite resin particles to form the composite resin particles and the colorant particles. It is preferably prepared by salting out / fusing.

As described above, by preparing the composite resin particles in a system in which no colorant is present, the polymerization reaction for obtaining the composite resin particles is not hindered. Therefore, according to the toner of the present invention, the excellent offset resistance is not impaired, and the fixing device is not stained or the image is not stained due to the accumulation of the toner.

Further, as a result of reliably performing the polymerization reaction for obtaining the composite resin particles, no monomer or oligomer remains in the obtained toner particles. No unpleasant odor is generated in the heat fixing step.

Further, the surface characteristics of the obtained toner particles are uniform and the charge amount distribution is sharp, so that an image having excellent sharpness can be formed for a long period of time. According to such a toner having a uniform composition, molecular weight, and surface characteristics among toner particles, good adhesion (high fixing strength) to an image support is maintained in an image forming method including a fixing step by a contact heating method. While improving the offset resistance and the anti-winding property,
An image having a moderate gloss can be obtained.

Next, each component used in the toner manufacturing process will be described in detail. (Polymerizable monomer) As a polymerizable monomer for producing the resin (binder) used in the present invention, a hydrophobic monomer is an essential component, and a crosslinkable monomer is optionally used. Used. As described below, it is desirable to contain at least one monomer having an acidic polar group or a monomer having a basic polar group. (1) Hydrophobic monomer The hydrophobic monomer constituting the monomer component is not particularly limited, and a conventionally known monomer can be used. In addition, one or two kinds may be used to satisfy the required characteristics.
More than one species can be used in combination.

Specifically, monovinyl aromatic monomers,
It is possible to use (meth) acrylate monomers, vinyl ester monomers, vinyl ether monomers, monoolefin monomers, diolefin monomers, halogenated olefin monomers, and the like. it can.

Examples of the vinyl aromatic monomer include, for example,
Styrene, o-methylstyrene, m-methylstyrene,
p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, p-ethylstyrene, p-n-butylstyrene, p-tert-butylstyrene, p-n-hexylstyrene, p-n- Styrene monomers such as octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, 2,4-dimethylstyrene, and 3,4-dichlorostyrene, and derivatives thereof. .

As the acrylic monomer, acrylic acid,
Methacrylic acid, methyl acrylate, ethyl acrylate,
Butyl acrylate, 2-ethylhexyl acrylate,
Cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, ethyl β-hydroxyacrylate, propyl γ-aminoacrylate, stearyl methacrylate, methacryl Dimethylaminoethyl acrylate, diethylaminoethyl methacrylate and the like.

Examples of the vinyl ester monomer include vinyl acetate, vinyl propionate, vinyl benzoate and the like.

Examples of the vinyl ether monomer include vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl phenyl ether and the like.

Examples of the monoolefin-based monomer include ethylene, propylene, isobutylene, 1-butene, 1-pentene, 4-methyl-1-pentene and the like.

Examples of the diolefin-based monomer include butadiene, isoprene, chloroprene and the like. (2) Crosslinkable monomer A crosslinkable monomer may be added to improve the properties of the resin particles. Examples of the crosslinkable monomer include those having two or more unsaturated bonds such as divinylbenzene, divinylnaphthalene, divinyl ether, diethylene glycol methacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, and diallyl phthalate. (3) Monomer having acidic polar group Examples of the monomer having an acidic polar group include (a) an α, β-ethylenically unsaturated compound having a carboxyl group (—COOH) and (b) a sulfone group (− Α, β-ethylenically unsaturated compounds having (SO ₃ H). Examples of the α, β-ethylenically unsaturated compound having a —COO group of (a) include acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, cinnamic acid,
Monobutyl maleate, monooctyl maleate, and metal salts thereof such as Na and Zn can be given. Examples of the α, β-ethylenically unsaturated compound having an —SO ₃ H group of (b) include sulfonated styrene, its Na salt, allyl sulfosuccinic acid, octyl allyl sulfosuccinate, its Na salt, and the like. . (4) Monomer having a basic polar group Examples of the monomer having a basic polar group include (i) an amine group or a quaternary ammonium group having 1 to 1 carbon atoms.
2, preferably 2 to 8, particularly preferably 2, (meth) acrylic esters of aliphatic alcohols, (ii) (meth)
1 to 18 carbon atoms on acrylamide or N
(Meth) acrylic acid amide mono- or di-substituted with an alkyl group, (iii) a vinyl compound substituted with a heterocyclic group having N as a ring member, and (iv) N, N-diallyl-
Examples thereof include an alkylamine and a quaternary ammonium salt thereof. Among them, (i) a (meth) acrylate of an aliphatic alcohol having an amine group or a quaternary ammonium group is preferable as a monomer having a basic polar group. Examples of the (meth) acrylate of an aliphatic alcohol having an amine group or a quaternary ammonium group (i) include dimethylaminoethyl acrylate,
Dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, quaternary ammonium salts of the above four compounds, 3-dimethylaminophenyl acrylate, 2-hydroxy-3-
And methacryloxypropyltrimethylammonium salt. (Ii) (meth) acrylamide or (meth) acrylamide optionally mono- or dialkyl-substituted on N includes acrylamide,
Examples thereof include N-butylacrylamide, N, N-dibutylacrylamide, piperidylacrylamide, methacrylamide, N-butylmethacrylamide, N, N-dimethylacrylamide, N-octadecylacrylamide and the like. Examples of the vinyl compound (iii) substituted with a heterocyclic group having N as a ring member include vinylpyridine, vinylpyrrolidone, vinyl-N-methylpyridinium chloride, vinyl-N-ethylpyridinium chloride and the like. Examples of N, N-diallyl-alkylamine (iv) include N, N-diallylmethylammonium chloride, N, N-diallylethylammonium chloride and the like.

The polymerization initiator used in the present invention will be described. The radical polymerization initiator used in the present invention can be appropriately used as long as it is water-soluble. For example, persulfates (eg, potassium persulfate, ammonium persulfate, etc.),
Examples include azo compounds (for example, 4,4'-azobis-4-cyanovaleric acid and salts thereof, 2,2'-azobis (2-amidinopropane) salts, etc.), peroxide compounds and the like. Further, the above radical polymerization initiator can be used as a redox initiator in combination with a reducing agent, if necessary. The use of a redox initiator is preferable because the polymerization activity is increased, the polymerization temperature can be reduced, and the polymerization time can be further shortened.

As the polymerization temperature, any temperature may be selected as long as it is equal to or higher than the minimum radical generation temperature of the polymerization initiator. For example, a temperature in the range of 50 ° C. to 90 ° C. is used. However, by using a polymerization initiator started at room temperature, for example, a combination of hydrogen peroxide and a reducing agent (such as ascorbic acid), polymerization can be performed at room temperature or higher.

The chain transfer agent used in the present invention will be described. For the purpose of adjusting the molecular weight, a known chain transfer agent can be used. As a chain transfer agent,
Although not particularly limited, for example, octyl mercaptan,
Compounds having a mercapto group such as dodecyl mercaptan and tert-dodecyl mercaptan are used. In particular, a compound having a mercapto group is preferably used because it suppresses odor at the time of heating and fixing, and a toner for electrostatic image development having a sharp molecular weight distribution is obtained, and has excellent storage stability, fixing strength, and offset resistance. Preferably,
For example, ethyl thioglycolate, propyl thioglycolate, propyl thioglycolate, butyl thioglycolate, t-butyl thioglycolate, 2-ethylhexyl thioglycolate, octyl thioglycolate, decyl thioglycolate, dodecyl thioglycolate And compounds having a mercapto group of ethylene glycol, compounds having a mercapto group of neopentyl glycol, and compounds having a mercapto group of pentaerythritol. Of these, n-octyl-3-mercaptopropionate is particularly preferred from the viewpoint of suppressing odor during heating and fixing of the toner for electrostatic image development.

The surfactant used in the present invention will be described. In order to carry out miniemulsion polymerization using the above-mentioned polymerizable monomer, it is preferable to carry out oil droplet dispersion in an aqueous medium using a surfactant. Surfactants that can be used at this time are not particularly limited, but the following ionic surfactants can be mentioned as examples of suitable compounds.

Examples of the ionic surfactant include a sulfonate (sodium dodecylbenzenesulfonate,
Sodium arylalkyl polyether sulfonate,
3,3-disulfonediphenylurea-4,4-diazo-
Sodium bis-amino-8-naphthol-6-sulfonate, ortho-carboxybenzene-azo-dimethylaniline, 2,2,5,5-tetramethyl-triphenylmethane-4,4-diazo-bis-β-naphthol -6
Sodium sulfonate), sulfate salts (sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, etc.),
Fatty acid salts (sodium oleate, sodium laurate, sodium caprate, sodium caprylate, sodium caproate, potassium stearate, calcium oleate, etc.) are exemplified.

Further, nonionic surfactants can also be used. Specifically, for example, polyethylene oxide, polypropylene oxide, a combination of polypropylene oxide and polyethylene oxide, esters of polyethylene glycol and higher fatty acids, alkylphenol polyethylene oxide, esters of higher fatty acids and polyethylene glycol, esters of higher fatty acids and polypropylene oxide, Sorbitan esters and the like can be mentioned.

In the present invention, these surfactants are mainly used as an emulsifier at the time of emulsion polymerization, but they may be used for other steps or other purposes.

In the present invention, the charge retention function of the toner is maintained in a good state, the occurrence of fogging under high temperature and high quality is suppressed, and from the viewpoint of improving the transferability, the rise in the charge amount under low temperature and low humidity is suppressed. From the viewpoint of stabilizing the development amount, the content of the surfactant described above in the toner for developing an electrostatic image of the present invention is preferably 1 to 1000 ppm, more preferably 5 to 500 ppm, and particularly preferably 5 to 500 ppm. Preferably it is 7-100 ppm.

The aggregating agent used in the present invention will be described. The coagulant used in the present invention is preferably selected from metal salts. As the metal salt, a monovalent metal,
For example, salts of alkali metals such as sodium, potassium and lithium, divalent metals such as salts of alkaline earth metals such as calcium and magnesium, divalent metal salts such as manganese and copper, and trivalent metals such as iron and aluminum Metal salts and the like.

Specific examples of these metal salts are shown below.
Specific examples of metal salts of monovalent metals include sodium chloride,
Potassium chloride, lithium chloride, and metal salts of divalent metals include calcium chloride, zinc chloride, copper sulfate, magnesium sulfate, and manganese sulfate. Examples of the trivalent metal salt include aluminum chloride and iron chloride. These are appropriately selected according to the purpose. In general, the divalent metal salt has a smaller critical aggregation concentration (coagulation value or coagulation point) than the monovalent metal salt, and the trivalent metal salt has a smaller critical aggregation concentration.

The critical aggregation concentration referred to in the present invention is an index relating to the stability of a dispersion in an aqueous dispersion, and indicates the concentration at which aggregation occurs when an aggregating agent is added. This critical aggregation concentration varies greatly depending on the latex itself and the dispersant. For example, Seizo Okamura et al., Polymer Chemistry 17,601
(1960), and according to these descriptions, the value can be known. Also, as another method,
It is also possible to add a desired salt to the target particle dispersion at a different concentration, measure the ζ potential of the dispersion, and determine the salt concentration at the point where the ζ potential changes to be the critical aggregation concentration.

In the present invention, the polymer fine particle dispersion is treated using a metal salt so as to have a concentration higher than the critical aggregation concentration. At this time, of course, add the metal salt directly,
The addition as an aqueous solution is arbitrarily selected depending on the purpose. In the case of adding as an aqueous solution, the added metal salt needs to be at or above the critical aggregation concentration of the polymer particles with respect to the volume of the polymer particle dispersion and the total volume of the metal salt aqueous solution.

The concentration of the metal salt as the coagulant in the present invention may be at least the critical coagulation concentration, but is preferably added at least 1.2 times, more preferably at least 1.5 times the critical coagulation concentration.

In the present invention, from the viewpoint of suppressing excessive charging of the toner particles and imparting a uniform charging property, in particular, in order to stabilize and maintain the charging property with respect to the environment, the electrostatic image of the present invention is used. The toner for development preferably contains 250 to 20,000 ppm of the above-described metal elements (forms include metals and metal ions) in the toner,
More preferably, it is 800 to 5,000 ppm.

Further, in the present invention, 2
It is preferable that the total value of the trivalent (trivalent) metal element and the monovalent metal element added as the coagulation terminator described later is 350 to 35,000 ppm.

The amount of residual metal ions in the toner was measured using a fluorescent X-ray analyzer “System 3270” (manufactured by Rigaku Denki Kogyo Co., Ltd.) using a metal species of a metal salt (for example, (E.g., calcium derived from calcium chloride). As a specific measuring method, a plurality of toners having a known content ratio of the coagulant metal salt are prepared, 5 g of each toner is pelletized, and the content ratio of the coagulant metal salt (mass p
pm) and the relationship (calibration curve) between the fluorescent X-ray intensity (peak intensity) from the metal species of the metal salt is measured. Next, the toner (sample) whose content ratio of the coagulant metal salt is to be measured is similarly pelletized, and the fluorescence X from the metal species of the coagulant metal salt is determined.
The linear intensity is measured, and the content ratio, that is, “the residual amount of metal ions in the toner” can be obtained. (Molecular weight distribution of toner for developing electrostatic image) The toner of the present invention has a peak or shoulder of 100,000 to 1,000,000, and 1000 to 1,000,000.
It is preferably present at 50,000, and the peak or shoulder is 1
More preferably, it is present in the range of 100,000 to 1,000,000, 25,000 to 150,000 and 1000 to 50,000.

The molecular weight of the resin particles is as follows: a high molecular weight component having a peak or shoulder in the range of 100,000 to 1,000,000;
Resins containing at least both low molecular weight components having peaks or shoulders in the region from 00 to less than 50,000 are preferred. More preferably, it is preferable to use an intermediate molecular weight resin having a peak or shoulder at a peak molecular weight of 15,000 to 100,000. The method for measuring the molecular weight of a toner for developing an electrostatic image or the resin is THF (tetrahydrofuran). ) As a solvent is preferably measured by GPC (gel permeation chromatography).

That is, 1.0 ml of THF is added to 0.5 to 5 mg, more specifically, 1 mg of a measurement sample, and the mixture is sufficiently dissolved by stirring at room temperature using a magnetic stirrer or the like. Then, pore size 0.45-0.5
After treatment with a 0 μm membrane filter, GPC
Inject into GPC measurement conditions were as follows: stabilize the column at 40 ° C., flow THF at a flow rate of 1.0 ml per minute,
About 100 μl of a sample having a concentration of mg / ml is injected and measured. The column is preferably used in combination with a commercially available polystyrene gel column. For example, Shodex GPC KF-801, 802, 8 manufactured by Showa Denko KK
03, 804, 805, 806, 807, TSKgel G1000H, G2000H, manufactured by Tosoh Corporation,
G3000H, G4000H, G5000H, G600
0H, G7000H, TSK guard column
and combinations of n. As the detector, a refractive index detector (IR detector) or a UV detector may be used. In measuring the molecular weight of a sample, the molecular weight distribution of the sample is calculated using a calibration curve prepared using monodisperse polystyrene standard particles. It is preferable to use about 10 polystyrenes for preparing a calibration curve.

The toner particles for developing an electrostatic image of the present invention will be described. The particle diameter of the electrostatic image developing toner of the present invention is:
The number average particle size is preferably 2 to 10 μm, and more preferably 3 to 8 μm. This particle size is determined by the method of producing a toner for developing an electrostatic image, by using a flocculant (a salting-out agent).
And the amount of the organic solvent added, the fusion time, and the composition of the polymer.

When the number average particle diameter is 2 to 10 μm, in the fixing step, the number of toner fine particles for electrostatic image development having a large adhesive force which flies and adheres to the heating member to generate an offset is reduced. Efficiency is improved, and the halftone image quality is improved, and the image quality of fine lines, dots, and the like is improved.

The number average particle diameter of the toner for developing an electrostatic image is as follows:
It can be measured using a Coulter Counter TA-II, Coulter Multisizer, SLAD1100 (Shimadzu Corporation laser diffraction particle size analyzer) or the like.

In the present invention, a Coulter Multisizer was used, and an interface for outputting a particle size distribution (manufactured by Nikkaki Co., Ltd.) and a personal computer were connected. The particle size distribution and the average particle size were calculated by measuring the volume distribution of an electrostatic image developing toner having a size of 2 μm or more (for example, 2 to 40 μm) using an aperture of 100 μm as the aperture in the Coulter Multisizer. <Preferable range of shape factor of electrostatic image developing toner particles> The shape factor of the electrostatic image developing toner of the present invention is represented by the following formula, and the degree of roundness of the electrostatic image developing toner particles is as follows. Is shown.

Shape factor = ((maximum diameter / 2) ² × π) / projected area Here, the maximum diameter is defined by sandwiching the projected image of the toner particles for electrostatic image development on a plane by two parallel lines. Sometimes, the width of the particle at which the interval between the parallel lines is the largest. The projected area refers to the area of the projected image of the toner particles for electrostatic image development onto a plane. In the present invention, this shape factor is determined by taking a photograph of a toner image for electrostatic image development enlarged by a factor of 2000 with a scanning electron microscope,
The measurement was performed by analyzing a photographic image using "ANNING IMAGE ANALYZER" (manufactured by JEOL Ltd.). At this time, the shape factor of the present invention was measured by the above formula using 100 toner particles for electrostatic image development.

The toner for developing an electrostatic image of the present invention contains 65 to 65 toner particles having a shape coefficient in the range of 1.2 to 1.6.
Preferably, the number is at least 70% by number, more preferably at least 70% by number of toner particles having a shape factor in the range of 1.2 to 1.6.

When the number of toner particles having a shape factor in the range of 1.0 to 1.6 is at least 65% by number, the triboelectrification property in the developer conveying member and the like becomes more uniform, and the excessively charged toner Is not accumulated, and the toner is more easily exchanged than the surface of the developer conveying member. Therefore, problems such as a development ghost are less likely to occur. Further, the toner particles are less likely to be crushed, so that the contamination of the charging member is reduced, and the chargeability of the toner is stabilized.

The method for controlling the shape factor is not particularly limited. For example, a method of spraying toner particles in a hot air flow, a method of repeatedly applying mechanical energy due to an impact force in a gas phase, or a method of adding a toner particle in a solvent that does not dissolve a toner to impart a swirling flow, etc. Thus, there is a method in which a toner having a shape factor of 1.2 to 1.6 is prepared, and is added to a normal toner so as to fall within the range of the present invention. Further, there is a method in which the overall shape is controlled at the stage of adjusting the so-called polymerization toner, and the toner whose shape factor is adjusted to 1.2 to 1.6 is similarly added to a normal toner to adjust the toner.

The toner for developing an electrostatic image of the present invention includes:
When the particle diameter of the toner particles for developing an electrostatic image is represented by D (μm), the natural logarithm lnD is plotted on the horizontal axis, and the horizontal axis is 0.23
High in the histogram showing particle size distribution of number-based divided into a plurality of classes, the relative frequency of the electrostatic image developing toner particles contained in the modal class (m _1), the next frequency of the most frequent class intervals It is preferable that the toner for electrostatic image development has a sum (M) of 70% or more with respect to the relative frequency (m ₂ ) of the toner particles for electrostatic image development included in the class.

When the sum (M) of the relative frequency (m ₁ ) and the relative frequency (m ₂ ) is 70% or more, the dispersion of the particle size distribution of the toner particles for electrostatic image development is narrowed. By using the charge image developing toner in the image forming step, the occurrence of selective development can be reliably suppressed.

In the present invention, the histogram showing the number-based particle size distribution is obtained by plotting the natural logarithm lnD (D: the particle size of each toner particle for developing an electrostatic image) into a plurality of classes (0 to 0) at intervals of 0.23. 0.23: 0.23 to 0.46: 0.4
6-0.69: 0.69-0.92: 0.92-1.1
5: 1.15 to 1.38: 1.38 to 1.61: 1.6
1-1.84: 1.84-2.07: 2.07-2.3
0: 2.30 to 2.53: 2.53 to 2.76 ...)
This is a histogram showing the number-based particle size distribution divided into the following, and this histogram transfers the particle size data of the sample measured by the Coulter Multisizer to the computer via the I / O unit according to the following conditions. It is produced by a computer using a particle size distribution analysis program.

The “toner particles without corners” according to the present invention will be described with reference to FIG. In the toner according to the present invention, the ratio of the toner particles having no corners in the toner particles constituting the toner is preferably 50% by number or more, more preferably 70% by number or more.

When the ratio of the toner particles having no corners is 50% by number or more, the gap of the transferred toner layer (powder layer) is reduced, the fixing property is improved, and the offset is hardly generated. In addition, abrasion, toner particles that are easily broken and toner particles having a portion where charges are concentrated are reduced, the charge amount distribution is sharpened, the chargeability is stable,
Good image quality can be formed over a long period of time.

The term "toner particles having no corners" refers to toner particles substantially free of protrusions where charges are concentrated or protrusions that are easily worn by stress. Are called toner particles without corners. That is,
As shown in FIG. 1A, when the major axis of the toner particle T is L, a circle C having a radius (L / 10) is in contact with the peripheral line of the toner particle T at one point and the inside is inward. The case where the circle C does not substantially protrude outside the toner T when the roller is rolled is referred to as “toner particles without corners”. “When the protrusion does not substantially protrude” means that the protrusion having the protruding circle is 1
Below the point. Also, "Long diameter of toner particles"
The term “width” refers to the width of a particle at which the distance between the parallel lines becomes maximum when the projected image of the toner particles on the plane is sandwiched between two parallel lines. FIGS. 1B and 1C show projected images of toner particles having corners, respectively.

The ratio of the toner particles having no corners was measured as follows. First, a photograph in which the toner particles are enlarged by a scanning electron microscope is taken, and further enlarged to obtain a photographic image of 15,000 times. Next, the presence or absence of the corners is measured for this photographic image. This measurement was performed for 100 toner particles.

The method for obtaining a toner having no corners is not particularly limited. For example, as described above, as a method of controlling the shape coefficient, a method of spraying toner particles into a hot air flow, a method of repeatedly applying mechanical energy by an impact force in a gas phase, or a method of dissolving a toner It can be obtained by adding to a solvent that does not contain and giving a swirling flow.

A preferred method for producing the toner for developing an electrostatic image of the present invention will be described. <Process of dissolving or dispersing each material of resin, colorant, and wax in an organic solvent to form an oil phase component, and granulating the oil phase component in an aqueous solvent> Binder resin (also referred to as binder)
In an organic solvent capable of dissolving a binder resin, a charge controllable resin,
An electrostatic image comprising: a step of dissolving or dispersing a colorant and a release agent to prepare an oil component; and a step of granulating an electrostatic image developing toner from a state in which the oil component is dispersed in an aqueous medium. This is a method for producing a developing toner.

The step of dissolving and dispersing a binder resin, a colorant, and a wax in an organic solvent capable of dissolving the binder resin to prepare an oily component includes the binder resin, the charge control resin, the colorant, And a step of mixing and releasing the release agent in an organic solvent capable of dissolving the binder resin.

The organic solvent capable of dissolving the binder resin includes
General organic solvents are used. For example, hydrocarbons such as toluene, xylene and hexane, halogenated hydrocarbons such as methylene chloride, chloroform and dichloroethane, alcohols such as methanol and ethanol, ethers such as tetrahydrofuran, esters such as methyl acetate, ethyl acetate and butyl acetate. And ketones such as acetone, methyl ethyl ketone, and cyclohexanone. Among them, ethyl acetate, methyl ethyl ketone and the like are preferable from the viewpoint of the solubility of the resin and the solvent removing property. These may be used alone or as a mixture. The step of granulating the toner for electrostatic image development from a state in which the oily component is dispersed in the aqueous medium means that the oily component adjusted in the step is solidified from the state in which the oily component is dispersed in the aqueous medium to produce particles. And
This is a step of drying this to obtain a toner for developing an electrostatic image.

The method for producing the particles is as follows.
A method of dissolving and dispersing the charge control resin, the coloring agent, the release agent, and other materials in a solvent, suspending and dispersing in a water-based medium, and then removing the solvent. A method of precipitating particles by adding a poor solvent, the binder resin, the charge control resin, the coloring agent, the release agent, and melt-dispersed in a water-based medium containing a heated melt, Thereafter, a method of forming particles by cooling, a method of suspending and dispersing a mixed solution containing a polymerizable monomer, the coloring agent, the release agent, and other materials in an aqueous medium, and thereafter polymerizing the monomer And the like.

As the aqueous medium, water is mainly used, but a water-soluble solvent may be mixed. Further, it is preferable to add a dispersant in terms of particle size distribution. Dispersants include tricalcium phosphate, hydroxyapatite, calcium carbonate, titanium oxide, aluminum hydroxide, magnesium hydroxide, barium sulfate, silica, cellulose, hydroxypropylmethylcellulose, methylcellulose, carboxymethylcellulose, starch, polyvinyl alcohol, and polyacryl. Acids and the like. The amount of the dispersant is preferably 0 to 20 parts by mass with respect to 100 parts by mass of the mother liquor.

As a stirring method for producing particles, it is desirable to apply shearing, and a homogenizer, a colloid mill, a dissolver, or the like is used.

For drying, a through-air drying device, a spray drying device,
A rotary dryer, a flash dryer, a fluidized-bed dryer, a heat transfer heating dryer, a freeze dryer, and the like are known, and any of them can be used.

The binder resin according to the present invention will be described.
In order to produce the binder resin according to the present invention, styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, α-methyl styrene, p-chloro Styrene, 3,4-dichlorostyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn Styrene or a styrene derivative such as nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-methacrylate −
Butyl, n-octyl methacrylate, 2-methacrylic acid
Ethylhexyl, stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, methacrylate derivatives such as dimethylaminoethyl methacrylate, methyl acrylate,
Ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, phenyl acrylate, etc. Acrylate derivatives, ethylene, propylene, olefins such as isobutylene, vinyl chloride, vinylidene chloride, vinyl bromide, vinyl fluoride, halogenated vinyls such as vinylidene fluoride,
Vinyl esters such as vinyl propionate, vinyl acetate and vinyl benzoate; vinyl ethers such as vinyl methyl ether and vinyl ethyl ether; vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone and vinyl hexyl ketone; N-vinyl carbazole; N-vinyl compounds such as vinylindole and N-vinylpyrrolidone; vinyl compounds such as vinylnaphthalene and vinylpyridine; and acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile and acrylamide. These vinyl monomers can be used alone or in combination.

Further, it is more preferable to use a polymerizable monomer constituting the resin in combination with one having an ionic dissociation group. For example, those having a substituent such as a carboxyl group, a sulfonic acid group, and a phosphoric acid group as a constituent group of a monomer, specifically, acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, and fumaric acid. Acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester, styrenesulfonic acid, allylsulfosuccinic acid, 2-acrylamido-2-methylpropanesulfonic acid, acid phosphooxyethyl methacrylate, 3
-Chloro-2-acid phosphooxypropyl methacrylate and the like. Furthermore, polyfunctional such as divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol diacrylate, etc. Resins having a crosslinked structure can also be obtained by using a hydrophilic vinyl.

These polymerizable monomers can be polymerized using a radical polymerization initiator. In this case, an oil-soluble polymerization initiator can be used in the suspension polymerization method. As the oil-soluble polymerization initiator, 2,2'-azobis- (2,4
-Dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis (cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvalero Nitroles, azo or diazo polymerization initiators such as azobisisobutyronitrile,
Benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide, dicumyl peroxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, 2,2-bis- (4
4-tert-butylperoxycyclohexyl) propane,
Examples include peroxide-based polymerization initiators such as tris- (t-butylperoxy) triazine and polymer initiators having a peroxide in a side chain. When an emulsion polymerization method is used, a water-soluble radical polymerization initiator can be used. As the water-soluble polymerization initiator, potassium persulfate,
Examples thereof include persulfates such as ammonium persulfate, azobisaminodipropane acetate, azobiscyanovaleric acid and salts thereof, and hydrogen peroxide.

The dispersion stabilizers include tricalcium phosphate, magnesium phosphate, zinc phosphate, aluminum phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, and calcium sulfate. , Barium sulfate,
Bentonite, silica, alumina and the like can be mentioned. Further, polyvinyl alcohol, gelatin, methyl cellulose, sodium dodecylbenzenesulfonate,
Those commonly used as surfactants such as ethylene oxide adducts and higher alcohol sodium sulfate can be used as dispersion stabilizers.

The binder resin according to the present invention preferably has a glass transition point of 20 to 90 ° C. and a softening point of 80 to 220 ° C. The glass transition point is measured by a differential calorimetric analysis method, and the softening point can be measured by a Koka type flow tester.
Further, these resins preferably have a number average molecular weight (Mn) of 1,000 to 100,000 and a weight average molecular weight (Mw) of 2,000 to 1,000,000 as measured by GPC (gel permeation chromatography). Further, as a molecular weight distribution, Mw / Mn is 1.5 to 100,
Particularly, those having 1.8 to 70 are preferable.

The colorant used as a component of the toner for developing an electrostatic image of the present invention will be described.

Examples of the colorant (colorant particles used for salting out and fusing with the composite resin particles) constituting the electrostatic image developing toner of the present invention include various inorganic pigments, organic pigments, and dyes. be able to. Conventionally known inorganic pigments can be used. Specific inorganic pigments are exemplified below.

Examples of black pigments include furnace black, channel black, acetylene black,
Carbon black such as thermal black and lamp black, and magnetic powder such as magnetite and ferrite are also used.

These inorganic pigments can be used alone or in combination of two or more as desired. The amount of the pigment added is 2 to 20% by mass relative to the polymer, preferably 3 to 20% by mass.
15% by weight is selected.

When used as a toner for developing a magnetic electrostatic image, the above-mentioned magnetite can be added.
In this case, from the viewpoint of imparting predetermined magnetic properties, it is preferable to add 20 to 60% by mass to the electrostatic image developing toner.

Conventionally known organic pigments and dyes can also be used. Specific examples of organic pigments and dyes are shown below.

Examples of magenta or red pigments include C.I. I. Pigment Red 2, C.I. I. Pigment Red 3, C.I. I. Pigment Red 5, C.I. I. Pigment Red 6, C.I. I. Pigment Red 7, C.I.
I. Pigment Red 15, C.I. I. Pigment Red 16, C.I. I. Pigment Red 48: 1, C.I. I. Pigment Red 53: 1, C.I. I. Pigment Red 5
7: 1, C.I. I. Pigment Red 122, C.I. I. Pigment Red 123, C.I. I. Pigment Red 13
9, C.I. I. Pigment red 144, C.I. I. Pigment Red 149, C.I. I. Pigment Red 166,
C. I. Pigment Red 177, C.I. I. Pigment Red 178, C.I. I. Pigment Red 222 and the like.

The pigments for orange or yellow include:
For example, C.I. I. Pigment Orange 31, C.I. I. Pigment Orange 43, C.I. I. Pigment Yellow 1
2, C.I. I. Pigment Yellow 13, C.I. I. Pigment Yellow 14, C.I. I. Pigment Yellow 15,
C. I. Pigment Yellow 17, C.I. I. Pigment Yellow 93, C.I. I. Pigment Yellow 94, C.I.
I. Pigment yellow 138, C.I. I. Pigment yellow 180, C.I. I. Pigment Yellow 185,
C. I. Pigment yellow 155, C.I. I. Pigment Yellow 156 and the like.

Examples of green or cyan pigments include C.I. I. Pigment Blue 15, C.I. I. Pigment Blue 15: 2, C.I. I. Pigment Blue 15:
3, C.I. I. Pigment Blue 16, C.I. I. Pigment Blue 60, C.I. I. Pigment Green 7 and the like.

As the dye, for example, C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 122, C.I. I. Solvent Yellow 19,
44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, C.I.
I. Solvent Blue 25, 36, 60, 70
93 and 95 can be used, and a mixture thereof can also be used.

These organic pigments and dyes can be used alone or in combination of two or more as desired.
The amount of the pigment to be added is 2 to 20% by mass, preferably 3 to 15% by mass, based on the polymer.

The colorant (colorant particles) constituting the electrostatic image developing toner of the present invention may be surface-modified.
As the surface modifier, a conventionally known one can be used, and specifically, a silane coupling agent, a titanium coupling agent, an aluminum coupling agent and the like can be preferably used. Examples of the silane coupling agent include alkoxysilanes such as methyltrimethoxysilane, phenyltrimethoxysilane, methylphenyldimethoxysilane, and diphenyldimethoxysilane, siloxanes such as hexamethyldisiloxane, γ-chloropropyltrimethoxysilane, and vinyltrimethoxysilane. Chlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-ureido Propyltriethoxysilane and the like. Examples of the titanium coupling agent include, for example, TTS, 9S, 38S, 41B, and 46, which are commercially available under the trade name “Plenact” manufactured by Ajinomoto Co.
B, 55, 138S, 238S, etc., commercial products A-1, B-1, TOT, TST, TAA, TAT, manufactured by Nippon Soda Co., Ltd.
TLA, TOG, TBSTA, A-10, TBT, B-
2, B-4, B-7, B-10, TBSTA-400,
TTS, TOA-30, TSDMA, TTAB, TTO
P and the like. Examples of the aluminum coupling agent include “Preneact AL-M” manufactured by Ajinomoto Co.

The addition amount of these surface modifiers is preferably from 0.01 to 20% by mass, more preferably from 0.1 to 5% by mass, based on the colorant.

As a method for modifying the surface of the colorant particles, there is a method in which a surface modifier is added to a dispersion of the colorant particles, and the system is heated to cause a reaction.

The surface-modified colorant particles are collected by filtration, and are subjected to drying treatment after repeated washing and filtration with the same solvent. (Release Agent) The toner for developing an electrostatic image used in the present invention is preferably a toner for developing an electrostatic image in which resin particles containing a release agent are fused in an aqueous medium.
By salting out / fusing the resin particles having the release agent encapsulated in the resin particles with the colorant particles in an aqueous medium in this manner, the toner for developing an electrostatic image in which the release agent is finely dispersed is obtained. Obtainable.

In the toner for developing an electrostatic image of the present invention, a low molecular weight polypropylene (number average molecular weight = 1) is used as a releasing agent.
500 to 9000), low molecular weight polyethylene and the like, and particularly preferably an ester compound represented by the following formula.

R ^1- (OCO-R ² ) _{n In the} formula, n is an integer of 1 to 4, preferably 2 to 4, more preferably 3 to 4, and particularly preferably 4. R ¹ and R ² are
The hydrocarbon group which may have a substituent is shown. R ¹ is
The carbon number is 1 to 40, preferably 1 to 20, and more preferably 2 to 5. R ² has 1 to 40 carbon atoms, preferably 1
6-30, more preferably 18-26.

Hereinafter, examples of typical compounds will be shown, but the present invention is not limited thereto.

[0147]

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[0148]

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The addition amount of the above compound is 1 to 30% by mass, preferably 2 to 20% by mass, more preferably 3 to 15% by mass based on the whole toner for developing an electrostatic image.

The toner for developing an electrostatic image of the present invention is preferably prepared by encapsulating the above-mentioned release agent in resin particles by miniemulsion polymerization, salting out and fusing together with the colored particles.

The external additives used in the present invention will be described. To the toner for developing an electrostatic image of the present invention, a so-called external additive can be added and used for the purpose of improving fluidity and cleaning property. These external additives are not particularly limited, and various inorganic fine particles, organic fine particles, and lubricants can be used.

As the inorganic fine particles that can be used as the external additive, conventionally known inorganic fine particles can be exemplified. Specifically, silica fine particles, titanium fine particles, alumina fine particles and the like can be preferably used. These inorganic fine particles are preferably hydrophobic.

Specific examples of the silica fine particles include commercially available products R-805, R-976, and R-95 manufactured by Nippon Aerosil Co., Ltd.
974, R-972, R-812, R-809, HVK-2150 and H-200 manufactured by Hoechst Co., Ltd., and commercial products TS-720, TS-530, TS manufactured by Cabot Co., Ltd.
-610, H-5, MS-5 and the like.

As specific examples of the titanium fine particles, for example,
Commercial products T-805 and T-60 manufactured by Nippon Aerosil Co., Ltd.
4. Commercial products MT-100S and MT-1 manufactured by Teika Co., Ltd.
00B, MT-500BS, MT-600, MT-60
0SS, JA-1, commercial product TA- manufactured by Fuji Titanium Co., Ltd.
300SI, TA-500, TAF-130, TAF-
510, TAF-510T, and commercial products IT-S, IT-OA, IT-OB, IT-OC manufactured by Idemitsu Kosan Co., Ltd.

Specific examples of the alumina fine particles include, for example, commercial products RFY-C and C-C available from Nippon Aerosil Co., Ltd.
604, a commercial product TTO-55 manufactured by Ishihara Sangyo Co., Ltd., and the like.

Examples of the organic fine particles that can be used as an external additive include spherical fine particles having a number average primary particle diameter of about 10 to 2000 nm. Examples of the constituent material of the organic fine particles include polystyrene, polymethyl methacrylate, and styrene-methyl methacrylate copolymer.

Examples of the lubricant which can be used as an external additive include metal salts of higher fatty acids. Specific examples of such metal salts of higher fatty acids include metal stearate salts such as zinc stearate, aluminum stearate, copper stearate, magnesium stearate, and calcium stearate; zinc oleate, manganese oleate, iron oleate, and olein. Metal oleate such as copper oxyphosphate and magnesium oleate; metal palmitate such as zinc palmitate, copper palmitate, magnesium palmitate and calcium palmitate; metal linoleate such as zinc linoleate and calcium linoleate; ricinol And metal salts of ricinoleic acid such as zinc acid and calcium ricinoleate.

The addition amount of the external additive is preferably about 0.1 to 5% by mass based on the electrostatic image developing toner.

In the step of adding the above-mentioned external additive to the dried toner particles for electrostatic image development, a device used for adding the external additive may be a turbular mixer,
Various known mixing devices such as a Hensiel mixer, a Nauter mixer, and a V-type mixer can be used. [3] Developer The electrostatic image developing toner of the present invention may be used as a one-component developer or a two-component developer.

When used as a one-component developer, a non-magnetic one-component developer or a toner for developing an electrostatic image is used.
A magnetic one-component developer containing magnetic particles of about 0.5 μm is used, and any of them can be used.

Further, it can be used as a two-component developer by mixing with a carrier. In this case, as the magnetic particles of the carrier, conventionally known materials such as metals such as iron, ferrite, and magnetite, and alloys of these metals with metals such as aluminum and lead can be used. Particularly, ferrite particles are preferable. The magnetic particles have an average particle size of 15 to 100 μm, more preferably 25 to 80 μm.
Is better.

The average particle size of the carrier is typically measured by a laser diffraction particle size distribution analyzer “HELOS” equipped with a wet disperser (SYMPAT).
EC).

The carrier is preferably a carrier in which magnetic particles are further coated with a resin, or a so-called resin-dispersed carrier in which magnetic particles are dispersed in a resin. The resin composition for coating is not particularly limited, for example,
An olefin resin, a styrene resin, a styrene-acrylic resin, a silicone resin, an ester resin, a fluorine-containing polymer resin, or the like is used. The resin for forming the resin dispersion type carrier is not particularly limited, and known resins can be used. For example, a styrene-acrylic resin, a polyester resin, a fluororesin,
A phenol resin or the like can be used. [4] Image Forming Method The image forming method of the present invention comprises the steps of forming an electrostatic image on an electrostatic image carrier, and developing the electrostatic image with a developer containing the toner of the present invention to form a toner image And transferring the toner image onto a transfer member.

The toner of the present invention is suitable for an image forming method including a step of fixing an image forming support having a toner image formed thereon by passing the image forming support between a heating roller and a pressure roller constituting a fixing device. used.

An image forming apparatus is used for image formation. The image forming apparatus will be described. Cleaning conditions-Cleaning blade The cleaning blade is preferably an elastic rubber blade. The physical properties of the cleaning blade can be controlled at the same time by controlling the rubber hardness and the rebound resilience, whereby the torque fluctuation can be controlled to be small and the blade reversal can be suppressed more effectively. If the JISA hardness of the blade at 25 ± 5 ° C. is smaller than 65, the blade is likely to be inverted, and if it is larger than 80, the cleaning performance is reduced. On the other hand, if the rebound resilience exceeds 80, reversal of the blade is apt to occur, and if it is less than 20, the cleaning performance deteriorates. More preferable rebound resilience is 20 to 80. Young's modulus is 294-588 N / c
Those having a range of m ² are preferred. (Both the JISA hardness and the rebound resilience are measured based on the vulcanized rubber physical test method of JIS K6301. The value of the rebound resilience indicates%.) As the material of the elastic rubber blade used for the cleaning blade, urethane rubber, silicon rubber, Fluoro rubber, chloropyrene rubber, butadiene rubber, and the like are known. Of these, urethane rubber is particularly preferable because of its excellent wear characteristics as compared with other rubbers. For example, urethane rubber obtained by reacting and curing a polycaprolactone ester and a polyisocyanate described in JP-A-59-30574 is preferable.

In the present invention, the method of fixing the elastic rubber blade to the support member is preferably such that the elastic rubber blade is substantially held by the support member on the photosensitive member contact surface side. By employing such a holding method, torque fluctuation of the cleaning blade can be stabilized. -Appropriate pressure contact condition of blade The proper pressure contact condition of the elastic rubber blade to the photoreceptor surface is determined by a delicate balance of various characteristics, and is considerably narrow. It depends on the characteristics such as the thickness of the elastic rubber blade and the setting requires accuracy. However, the elastic rubber blades cannot be always set under appropriate conditions because the thickness of the elastic rubber blades may vary at the time of manufacture. May deviate from the appropriate area. Particularly when combined with an organic photosensitive layer using a high molecular weight binder resin, image defects such as filming and black spots are liable to occur when the organic photosensitive layer deviates from an appropriate region.

Therefore, it is necessary to take measures for canceling the variation in the characteristics of the elastic rubber blade. Even if the thickness of the elastic rubber blade varies, it does not affect the pressing force against the photosensitive member surface. The above setting method will be effective.

In the present invention, the free end of the elastic rubber blade is in the direction opposite to the rotation direction of the photoconductor (counter direction).
It is preferable to press in contact.

If necessary, the cleaning blade may be spray-coated with a fluorine-based lubricant on the edge of the cleaning blade, or may be further coated with the following fluorine-based polymer and fluorine-based polymer on the front end in the entire width direction. It is preferable to apply a dispersion in which the base resin powder is dispersed in a fluorine-based solvent. Organic Photoconductor Next, the organic photoconductor will be described.

In the present invention, the organic electrophotographic photoreceptor (organic photoreceptor) is constituted such that an organic compound has at least one of a charge generation function and a charge transport function which are indispensable for the constitution of the electrophotographic photoreceptor. Known organic electrophotographic photosensitive members, such as a photosensitive member composed of a known organic charge generating substance or an organic charge transporting substance, and a photosensitive member composed of a polymer complex having a charge generating function and a charge transporting function. Contains all body.

The structure of the organic photoreceptor used in the present invention will be described below. Conductive Support The conductive support used for the photoreceptor may be in the form of a sheet or a cylinder, but a cylindrical conductive support is preferred for compact design of the image forming apparatus. .

The cylindrical conductive support means a cylindrical support necessary for forming an image endlessly by rotating, and has a straightness of 0.1 mm or less and a run-out of 0.1 mm.
Conductive supports in the following ranges are preferred. Exceeding the ranges of the roundness and the shake make it difficult to form a good image.

As the conductive material, a metal drum of aluminum, nickel, or the like, a plastic drum on which aluminum, tin oxide, indium oxide, or the like is deposited, or a paper / plastic drum coated with a conductive substance can be used. The conductive support preferably has a specific resistance of 10 ³ Ωcm or less at room temperature.

The conductive support used in the present invention may have a surface on which a sealed alumite film is formed. The alumite treatment is usually performed in an acidic bath such as chromic acid, sulfuric acid, oxalic acid, phosphoric acid, boric acid, and sulfamic acid, but anodizing treatment in sulfuric acid gives the most preferable result. In the case of anodic oxidation treatment in sulfuric acid, it is preferable that the sulfuric acid concentration is 100 to 200 g / l, the aluminum ion concentration is 1 to 10 g / l, the liquid temperature is around 20 ° C., and the applied voltage is about 20 V. It is not limited. The average thickness of the anodic oxide coating is usually 2
0 μm or less, particularly preferably 10 μm or less. Intermediate Layer An intermediate layer having a barrier function may be provided between the conductive support and the photosensitive layer.

In order to improve the adhesiveness between the conductive support and the photosensitive layer or to prevent charge injection from the support,
An intermediate layer (including an undercoat layer) may be provided between the support and the photosensitive layer. Examples of the material for the intermediate layer include polyamide resins, vinyl chloride resins, vinyl acetate resins, and copolymer resins containing two or more of the repeating units of these resins. Among these undercoating resins, a polyamide resin is preferable as a resin capable of reducing an increase in residual potential due to repeated use. The thickness of the intermediate layer using these resins is preferably 0.01 to 0.5 μm.

The most preferably used intermediate layer is an intermediate layer using a curable metal resin obtained by thermally curing an organic metal compound such as a silane coupling agent and a titanium coupling agent. The thickness of the intermediate layer using a curable metal resin is
0.1 to 2 μm is preferred. Photosensitive Layer The photosensitive layer of the photoreceptor may have a single-layered structure in which a charge generation function and a charge transport function are provided on the intermediate layer in one layer, but more preferably, the function of the photosensitive layer is the charge generation function. It is preferable to adopt a configuration in which a layer (CGL) and a charge transport layer (CTL) are separated. By adopting a configuration in which functions are separated, an increase in residual potential due to repeated use can be controlled to be small, and other electrophotographic characteristics can be easily controlled according to the purpose. It is preferable that the photoreceptor for negative charging has a configuration in which a charge generation layer (CGL) is provided on the intermediate layer and a charge transport layer (CTL) is provided thereon. In the case of a positively charged photoreceptor, the order of the layer configuration is opposite to that of the negatively charged photoreceptor. The most preferred photosensitive layer structure of the present invention is a negatively charged photosensitive member having the function-separated structure.

The structure of the photosensitive layer of the function-separated negatively charged photosensitive member will be described below. Charge generation layer Charge generation layer: The charge generation layer contains a charge generation material (CGM). As other substances, a binder resin and other additives may be contained as necessary.

As the charge generation material (CGM), a known charge generation material (CGM) can be used. For example, phthalocyanine pigments, azo pigments, perylene pigments, azurenium pigments, and the like can be used. Among them, CGM that can minimize the increase in residual potential due to repeated use
Has a steric and potential structure capable of forming a stable aggregation structure among a plurality of molecules, and specifically includes CGM of a phthalocyanine pigment and a perylene pigment having a specific crystal structure. For example, Bragg angle 2θ for Cu-Kα ray
CGM such as titanyl phthalocyanine having a maximum peak at 27.2 ° and benzimidazole perylene having a maximum peak at 2θ of 12.4 have almost no deterioration due to repeated use, and the residual potential increase can be reduced.

When a binder is used as the CGM dispersion medium in the charge generation layer, a known resin can be used as the binder, but the most preferred resin is a formal resin, a butyral resin, a silicone resin, a silicone-modified butyral resin, a phenoxy resin. Resins. The ratio between the binder resin and the charge generating substance is preferably from 20 to 600 parts by mass per 100 parts by mass of the binder resin. By using these resins, the increase in residual potential due to repeated use can be minimized. The thickness of the charge generation layer is preferably from 0.01 to 2 μm. Charge transport layer Charge transport layer: The charge transport layer contains a charge transport material (CTM) and a binder resin for dispersing the CTM and forming a film.
As other substances, additives such as antioxidants may be contained as necessary.

As the charge transport material (CTM), a known charge transport material (CTM) can be used. For example, triphenylamine derivatives, hydrazone compounds, styryl compounds, benzidine compounds, butadiene compounds and the like can be used. These charge transport materials are usually dissolved in a suitable binder resin to form a layer. Among these, the CTM that can minimize the increase in residual potential due to repeated use has a high mobility and a characteristic in which the ionization potential difference with the CGM to be combined is 0.5 (eV) or less, and is preferably 0. .25 (eV) or less.

The ionization potential of CGM and CTM is measured with a surface analyzer AC-1 (manufactured by Riken Keiki Co., Ltd.).

Examples of the resin used for the charge transport layer (CTL) include polystyrene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, and alkyd. Resins, polycarbonate resins, silicone resins, melamine resins, and copolymer resins containing two or more of the repeating units of these resins. In addition to these insulating resins, poly-
A high-molecular organic semiconductor such as N-vinylcarbazole may be used.

The most preferred binder for these CTLs is a polycarbonate resin. Polycarbonate resins are most preferred for improving the dispersibility and electrophotographic properties of CTM. The ratio of the binder resin to the charge transporting material is preferably from 10 to 200 parts by mass per 100 parts by mass of the binder resin. The thickness of the charge transport layer is preferably from 10 to 40 μm. Protective layer Various resin layers can be provided as a protective layer of the photoreceptor. In particular, by providing a crosslinked resin layer, the organic photoreceptor of the present invention having high mechanical strength can be obtained.

Solvents or dispersion media used for forming layers such as an intermediate layer, a photosensitive layer and a protective layer include n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, and the like.
N, N-dimethylformamide, acetone, methyl ethyl ketone, methyl isopropyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, dichloromethane, 1,2-dichloroethane, 1,2-dichloropropane, 1,1,2-trichloroethane, 1,
1,1-trichloroethane, trichloroethylene, tetrachloroethane, tetrahydrofuran, dioxolan,
Examples thereof include dioxane, methanol, ethanol, butanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, and methyl cellosolve. Although the present invention is not limited to these, dichloromethane, 1,2-dichloroethane, methyl ethyl ketone and the like are preferably used. These solvents may be used alone or
It can also be used as a mixed solvent of more than one kind.

As a coating method for producing an organic electrophotographic photoreceptor, a coating method such as dip coating, spray coating, circular amount control type coating or the like is used. In order not to dissolve the membrane as much as possible,
In order to achieve a uniform coating process, it is preferable to use a coating process method such as spray coating or circular volume control type (a typical example is a circular slide hopper type). It is most preferable that the protective layer of the present invention employs the above-mentioned circular amount control type coating method. The circular amount control type coating is described in, for example,
No. -189061.

FIG. 2 is a cross-sectional view showing an example of a fixing device used in the image forming method using the electrostatic image developing toner of the present invention. The fixing device shown in FIG. And a pressure roller 20 that comes into contact with the pressure roller. In FIG. 2, T is a toner image for electrostatic image development formed on a transfer paper (image forming support).

The heating roller 10 has a coating layer 12 made of a fluororesin or an elastic body formed on the surface of a core metal 11 and includes a heating member 13 made of a linear heater.

The core metal 11 is made of metal and has an inner diameter of 10 to 70 mm. The metal constituting the metal core 11 is not particularly limited, but examples thereof include metals such as iron, aluminum and copper or alloys thereof.

The thickness of the core metal 11 is set to 0.1 to 15 mm, and is determined in consideration of the balance between the demand for energy saving (thinning) and the strength (depending on the constituent materials). For example,
In order to maintain a strength equivalent to that of a 0.57 mm iron core with an aluminum core, the wall thickness must be 0.8 mm.

As the fluororesin constituting the coating layer 12, PTFE (polytetrafluoroethylene) and PF
A (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) and the like.

The thickness of the coating layer 12 made of fluororesin is 1
It is 0-500 μm, preferably 20-400 μm.

When the thickness of the coating layer 12 made of fluororesin is 1
When the thickness is less than 0 μm, the function as a coating layer cannot be sufficiently exhibited, and the durability as a fixing device cannot be secured. On the other hand, the surface of the coating layer having a thickness of more than 500 μm is easily scratched by paper dust, and there is a problem that toner for developing an electrostatic image adheres to the scratched portion, thereby causing image stains.

As the elastic body constituting the coating layer 12, it is preferable to use silicone rubber and silicone sponge rubber having good heat resistance such as LTV, RTV and HTV.

Elastic Asker C constituting the coating layer 12
The hardness is less than 80 °, preferably less than 60 °.

The thickness of the coating layer 12 made of an elastic material is 0.1 to 30 mm, preferably 0.1 to 20 mm.
It is said.

Elastic Asker C constituting the coating layer 12
When the hardness exceeds 80 ° and when the thickness of the coating layer 12 is less than 0.1 mm, the nip for fixing cannot be increased, and the effect of soft fixing (for example, the smoothed interface The effect of improving the color reproducibility by the toner layer for developing an electrostatic image).

As the heating member 13, a halogen heater can be suitably used. The pressure roller 20
A coating layer 22 made of an elastic body is formed on the surface of the core metal 21. The elastic body constituting the coating layer 22 is not particularly limited, and examples thereof include urethane rubber and various soft rubbers such as silicone rubber and sponge rubber. It is preferable to use silicone sponge rubber.

Elastic Asker C constituting the coating layer 22
The hardness is less than 80 °, preferably less than 70 °, more preferably less than 60 °.

The thickness of the coating layer 22 is 0.1 to 30 mm.
And preferably 0.1 to 20 mm.

Elastic Asker C constituting the coating layer 22
When the hardness exceeds 80 ° and when the thickness of the coating layer 22 is less than 0.1 mm, the fixing nip cannot be increased, and the effect of soft fixing cannot be exhibited.

The material constituting the metal core 21 is not particularly limited, but examples thereof include metals such as aluminum, iron and copper or alloys thereof.

The contact load (total load) between the heating roller 10 and the pressure roller 20 is usually 40 to 350 N, preferably 50 to 300 N, more preferably 50 to 300 N.
250N. This contact load is applied to the heating roller 10.
Is specified in consideration of the strength (thickness of the core metal 11), for example, in the case of a heating roller having a core metal made of 0.3 mm iron, the heating roller is preferably set to 250 N or less.

Further, from the viewpoint of offset resistance and fixing property, the nip width is preferably 4 to 10 mm, and the surface pressure of the nip is 0.6 × 10 ⁵ Pa to 1.5 ×
It is preferably 10 ⁵ Pa.

An example of the fixing condition by the fixing device shown in FIG. 2 is as follows. Fixing temperature (surface temperature of heating roller 10)
Is 150 to 210 ° C., and the fixing linear velocity is 80 to 640 m.
m / sec.

The fixing device used in the present invention may be provided with a cleaning mechanism as needed. In this case, as a method of supplying the silicone oil to the upper roller (heating roller) of the fixing unit, a method of supplying and cleaning with a pad, a roller, a web, or the like impregnated with the silicone oil can be used.

As the silicone oil, those having high heat resistance are used, and polydimethyl silicone, polyphenylmethyl silicone, polydiphenyl silicone and the like are used. Since those having a low viscosity have a large outflow during use, those having a viscosity at 20 ° C. of 1 to 100 Pa · s are preferably used.

However, the effect of the present invention is particularly remarkably exhibited when an image is formed by a fixing device that does not supply silicone oil or that uses a very small amount of silicone oil. Therefore, even when the silicone oil is supplied, the supply amount is preferably 2 mg or less per A4 sheet.

By setting the supply amount of the silicone oil to 2 mg or less per A4 sheet, the amount of the silicone oil adhering to the transfer paper (image support) after fixing is reduced, and a ball-point pen is formed by the silicone oil adhering to the transfer paper. There is no difficulty in writing with an oil-based pen, etc., and the writing performance is not impaired.

Further, it is possible to avoid problems such as deterioration of the offset resistance with time due to deterioration of the silicone oil, and contamination of the optical system and the band electrode by the silicone oil.

Here, the supply amount of the silicone oil was adjusted by transferring the transfer paper (A) to a fixing device (between rollers) heated to a predetermined temperature.
100 sheets of 4 size white paper) are continuously passed, and the mass change (Δw) of the fixing device before and after the paper passing is measured and calculated (Δw / 100).

[0211]

EXAMPLES The present invention will be described below in detail with reference to examples, but embodiments of the present invention are not limited thereto.
In the following, “parts” means “parts by mass as active ingredients” unless otherwise specified. (Production Example of Titanium Oxide) Production Example 1 of Titanium Oxide A titanyl sulfate solution was slowly dropped into a 160 g / L sodium carbonate solution so that the solution temperature did not exceed 25 ° C., and the pH reached 10 Then, the dropwise addition of the titanyl sulfate solution was stopped. Next, the white precipitate of orthotitanic acid obtained by this neutralization was filtered and sufficiently washed until the sulfate group disappeared. The washed orthotitanate cake was repulped with pure water while maintaining the temperature at 30 ° C., and then heated and heated at 75 ° C. for 2 hours. After that, concentrated hydrochloric acid is added and T
The iO ₂ concentration was adjusted to 100 g / L and the hydrochloric acid concentration was adjusted to 5 g / L. Next, the mixture was heated with stirring and hydrolyzed at the boiling point for 4 hours, and then p-pulped with 400 g / L sodium hydroxide.
Neutralized to H7 and filtered and washed. The obtained titanium oxide was a titanium oxide coated with 90% of anatase type titanium oxide and having a specific surface area of 150 m ₂ / g. Next, the obtained titanium oxide was repulped with pure water, the pH was adjusted to 2.5 by adding 200 g / L hydrochloric acid, and then 20% by mass of isobutyltrimethoxysilane was added to TiO ₂ . After stirring and holding for 30 minutes, a 400 g / L aqueous sodium hydroxide solution was added to neutralize the mixture to pH 6.5, followed by filtration, washing with water,
After drying at 150 ° C., the product was finely pulverized with an air current pulverizer to obtain hydrophobic titanium oxide. The obtained titanium oxide is referred to as “titanium oxide 1”. -Production Example 2 of Titanium Oxide The same procedure as in Production Example 1 of Titanium Oxide was conducted except that the heat treatment of orthotitanic acid was performed at 60 ° C for 4 hours. still,
The properties of the titanium oxide obtained by hydrolysis are as follows: a specific surface area of 170 m containing 60% of anatase type titanium oxide.
² / g of titanium oxide. The obtained titanium oxide is referred to as “titanium oxide 2”. · Production Example 3 oxide Production Example 1 of titanium titanium oxide, the concentration of hydrochloric acid upon hydrolysis 2 g / L, except that the TiO ₂ concentration to 60 g / L was carried out in the same manner. The properties of the titanium oxide obtained by the hydrolysis were titanium oxide containing 95% by mass of anatase type titanium oxide and having a specific surface area of 145 m ² / g. The obtained titanium oxide is referred to as “titanium oxide 3”. Production Example 4 of Titanium Oxide 3% by mass of SiO ₂ and Al ₂ O ₃ were formed on the surface of the titanium oxide obtained in Production Example 2 of Titanium Oxide by a known method.
After washing with 10% by mass of the treated titanium oxide, the treated titanium oxide was repulped with pure water, and the pH was adjusted to 2.5 by adding 200 g / L hydrochloric acid.
20% by mass was added to iO ₂ . After stirring and holding for 30 minutes, a 400 g / L aqueous sodium hydroxide solution was added, and
The mixture was neutralized to 6.5, filtered, washed with water, dried at 150 ° C., and then finely pulverized with an air current pulverizer to obtain a hydrophobic titanium oxide having a specific surface area of 155 m ² / g. The obtained titanium oxide is referred to as “titanium oxide 4”. Production Example 5 of Titanium Oxide After the hydrophobic rutile-type titanium oxide obtained in Production Example 1 of Titanium Oxide was further subjected to a dry treatment of 10% by mass of normal butyltrimethoxysilane using a Henschel mixer,
Fine pulverization was performed with an airflow pulverizer to obtain hydrophobic titanium oxide. The obtained titanium oxide is referred to as “titanium oxide 5”. Production example 1 of titanium oxide for comparison Heat treatment at 45 ° C. for 2 hours, hydrochloric acid concentration 25 g / L
In the same manner as described above, titanium oxide having a specific surface area of 200 m ² / g coated with 45% of anatase type titanium oxide was obtained in the same manner. The obtained titanium oxide is referred to as “Comparative Titanium Oxide 1”
And Production Example 2 of Comparative Titanium Oxide Anatase-type hydrophilic titanium oxide fine powder (0.035 μm)
m, specific surface area: 120 m 2 / g), 1 part to water-based aqueous medium 100 parts and sufficiently stirred, 0.2 part of silane coupling agent (normal butyl trimethoxysilane) to the aqueous medium, The titanium particles are sufficiently stirred so that they do not coalesce, filtered after stirring, dried, and lightly crushed to obtain an anatase type treatment having an average particle size of 0.05 μm and a hydrophobicity of 70%. Titanium oxide was obtained. The obtained titanium oxide is referred to as “comparative titanium oxide 2”.

The details of the obtained titanium oxide are shown in Table 1 below.

[0213]

[Table 1]

[Production Example of Resin Particles for Toner] (Latex: 1HML) (1) Preparation of Core Particles (First Stage Polymerization) A 5000 ml separable flask equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introducing device. In addition, an anionic surfactant (sodium dodecyl sulfonate: SD
S) A surfactant solution (aqueous medium) in which 7.08 g was dissolved in 3010 g of ion-exchanged water was charged, and the solution was added under a nitrogen stream.
While stirring at a stirring speed of 0 rpm, the internal temperature was raised to 80 ° C.

To this surfactant solution was added 9.2 g of a polymerization initiator (potassium persulfate: KPS) in 200 g of ion-exchanged water.
Was added, and the temperature was adjusted to 75 ° C., and then 70.1 g of styrene and n-butyl acrylate 1 were added.
A monomer mixture composed of 9.9 g and 10.9 g of methacrylic acid was added dropwise over 1 hour, and the system was heated and stirred at 75 ° C. for 2 hours to perform polymerization (first-stage polymerization). Latex (a dispersion of resin particles composed of a high molecular weight resin) was prepared. This is designated as “latex (1H)”. (2) Formation of intermediate layer (second stage polymerization) In a flask equipped with a stirrer, styrene 10
A compound mixture of 5.6 g, 30.0 g of n-butyl acrylate, 6.4 g of methacrylic acid, and 5.6 g of n-octyl-3-mercaptopropionic acid ester was mixed with a compound release agent 19). 0 g was added, and the mixture was heated to 80 ° C. and dissolved to prepare a monomer solution.

On the other hand, an anionic surfactant (SDS)
A surfactant solution obtained by dissolving 1.6 g in 2700 ml of ion-exchanged water was heated to 80 ° C.
After adding 28 g of the latex (1H), which is a dispersion liquid of core particles, in terms of solid content, using a mechanical dispersion machine “CLEARMIX (CLEARMIX)” (manufactured by M Technique Co., Ltd.) having a circulation path, The monomer solution of 19) is mixed and dispersed, and a uniform dispersed particle diameter (284 nm) is obtained.
A dispersion liquid (emulsion liquid) containing emulsified particles (oil droplets) having the following formula was prepared.

Next, to this dispersion liquid (emulsion liquid), an initiator solution obtained by dissolving 5.1 g of a polymerization initiator (KPS) in 240 ml of ion-exchanged water and 750 ml of ion-exchanged water were added.
This system is heated and stirred at 80 ° C. for 3 hours to carry out polymerization (second-stage polymerization), thereby obtaining a latex (a composite resin particle having a structure in which the surface of a resin particle composed of a high molecular weight resin is coated with an intermediate molecular weight resin). Dispersion). This is referred to as “latex (1HM)”. (3) Formation of outer layer (third stage polymerization) To latex (1HM) obtained as described above, 7.4 g of polymerization initiator (KPS) was added to 200 ml of ion-exchanged water.
Was added thereto, and 300 g of styrene and n-butyl acrylate 95 were added under a temperature condition of 80 ° C.
g, 15.3 g of methacrylic acid, and 10.4 g of n-octyl-3-mercaptopropionate were dropped over 1 hour. After completion of the dropping, polymerization (third-stage polymerization) is carried out by heating and stirring for 2 hours, and then cooled to 28 ° C. to form a latex (a central portion composed of a high molecular weight resin, an intermediate layer composed of an intermediate molecular weight resin, A dispersion liquid of composite resin particles having an outer layer made of a molecular weight resin and containing the exemplified compound 19) in the intermediate layer was obtained. This latex is referred to as “latex (1HML)”.

The composite resin particles constituting this latex (1HML) were 138,000, 80,000 and 13,000.
The composite resin particles had a number average particle size of 102 nm. [Example of preparation of composite resin particles] (1) Preparation of core particles (first-stage polymerization) In a flask equipped with a stirrer, styrene 1 was added.
To a monomer mixture consisting of 05.6 g, n-butyl acrylate 30.0 g, and methacrylic acid 6.4 g, 72.0 g of a release agent exemplified compound 16) was added, and the mixture was heated to 80 ° C. and dissolved. A monomer solution was prepared.

On the other hand, an anionic surfactant (SDS)
A surfactant solution obtained by dissolving 1.6 g in 2700 ml of ion-exchanged water was heated to 80 ° C.
Mechanical dispersion machine with a circulation path "CLEARMIX (CL
EARMIX) "(manufactured by M Technique Co., Ltd.) to mix and disperse the monomer solution of Exemplified Compound 16) to obtain a dispersion liquid containing emulsified particles (oil droplets) having a uniform dispersed particle diameter (268 nm) ( Emulsified liquid) was prepared.

Next, an initiator solution in which 5.1 g of a polymerization initiator (KPS) was dissolved in 240 ml of ion-exchanged water and 750 ml of ion-exchanged water were added to the dispersion (emulsion liquid). (First stage polymerization) by heating and stirring for 3 hours to prepare a latex (a dispersion of resin particles composed of a high molecular weight resin). This is designated as “latex (2H)”. (2) Formation of outer layer (second stage polymerization) 14.8 g of polymerization initiator (KPS) was added to 400 ml of deionized water to latex (2H) obtained as described above.
Was added thereto, and under a temperature condition of 80 ° C., 600 g of styrene and 190 g of n-butyl acrylate.
g, 30.0 g of methacrylic acid, and 20.8 g of n-octyl-3-mercaptopropionate were dropped over 1 hour. After completion of the dropping, polymerization (second-stage polymerization) is carried out by heating and stirring for 2 hours, and then cooled to 28 ° C. to form a latex (having a central portion composed of a high molecular weight resin and an outer layer composed of a low molecular weight resin. ,
A dispersion liquid of composite resin particles containing the exemplified compound 16) in the center was obtained. This latex is referred to as “latex (2HL)”.

The composite resin particles constituting the latex (2HL) had peak molecular weights of 168,000 and 11,000, and the weight average particle diameter of the composite resin particles was 126 nm. [Production Examples 1 to 4 of colored particles] 59.0 g of sodium n-dodecyl sulfate was dissolved in 1600 ml of ion-exchanged water with stirring. While stirring the solution, 420.0 g of carbon black "REGAL 330" (manufactured by Cabot) is gradually added, and then colored by dispersing using "CLEARMIX" (manufactured by M Technique Co., Ltd.). A dispersion of agent particles (hereinafter referred to as a colorant dispersion) was prepared.
When the particle size of the colorant particles in this colorant dispersion was measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.), the weight average particle size was 98 nm.

A latex (1HML) of 420.7 g (in terms of solid content), 900 g of ion-exchanged water, and 166 g of a colorant dispersion were subjected to a temperature sensor, a cooling pipe, a nitrogen introducing device, a stirring device, and a particle size and shape monitoring device. The mixture was placed in the attached reaction vessel and stirred. After adjusting the internal temperature to 30 ° C,
To this solution was added a 5 mol / L aqueous sodium hydroxide solution to adjust the pH to 11.0.

Subsequently, magnesium chloride hexahydrate12.
An aqueous solution obtained by dissolving 1 g in 1000 ml of ion-exchanged water,
The solution was added at 30 ° C. over 10 minutes with stirring. After standing for 3 minutes, heating was started, and the temperature of the system was raised to 90 ± 3 ° C. over 6 to 10 minutes (heating rate = 10 ° C./min). In this state, the particle size of the associated particles was measured with a “Coulter counter TA-II”, and when the volume average particle size became 5.5 μm, 80.4 g of sodium chloride was added to ion-exchanged water 1.
An aqueous solution dissolved in 000 ml was added to stop the particle growth.
The fusion was continued by heating and stirring for １５15 hours. Then, it is cooled to 30 ° C under the condition of 8 ° C / min,
Hydrochloric acid was added to adjust the pH to 2.0, and stirring was stopped. The formed associated particles are filtered using a Nutsche, washed repeatedly with ion-exchanged water, then dried using a flash jet dryer at an inlet air temperature of 60 ° C., and then at a temperature of 60 ° C. using a fluidized bed dryer. After drying, colored particles containing the exemplary compound 19) as a release agent were obtained. In the monitoring of the salting-out / fusion step and the shape control step, by controlling the number of rotations of stirring and the heating time, the variation coefficient of the shape and the shape factor is controlled, and the variation coefficient of the particle size and the particle size distribution can be arbitrarily set. By adjustment, colored particles 1 to 4 having the shape characteristics and particle size distribution characteristics shown in Table 2 were obtained. [Production Examples 5-8 of colored particles] Colored particle production examples 1-4 except that 420.7 g (in terms of solid content) of latex (2HL) was used instead of latex (1HML) and the aging treatment time was changed. Similarly, colored particles 5 to 8 having the shape characteristics and the particle size distribution characteristics shown in Table 2 were obtained.

The details of the obtained colored particles are shown in Table 2 below.

[0225]

[Table 2]

Examples 1 to 12 and Comparative Examples 1 and 2 Each of the colored particles 1 to 8 obtained as described above was treated with hydrophobic silica (number-average primary particle diameter = 10 nm, hydrophobicity = 6).
3) was added at a ratio of 1.0% by mass, and hydrophobic titanium oxides shown in Table 3 were added at a ratio of 0.8% by mass, and mixed with a Henschel mixer.
The shape and particle size of these colored particles are not changed by the addition of an external additive.

[0227]

[Table 3]

[Preparation of Carrier] (Production of Ferrite Core Material) MnO _{2 2} mol%, Fe ₂ O
_After pulverizing, mixing and drying 378 mol% for 2 hours in a wet ball mill, it was calcined by holding at 900 ° C. for 2 hours, and pulverized in a ball mill for 3 hours to form a slurry. A dispersant and a binder are added, and the mixture is granulated and dried by a spray drier. Thereafter, the mixture is subjected to main firing at 1200 ° C. for 3 hours to have an average grain diameter of 5.2 μm and a resistance of 4.3 ×
10 ⁸ ferrite core particles were obtained. (Manufacture of carrier) Using sodium benzenesulfonate having an alkyl group having 12 carbon atoms as a surfactant,
A copolymer of cyclohexyl methacrylate / methyl methacrylate (copolymerization ratio: 5/5) was synthesized by an emulsion polymerization method using an aqueous medium having a concentration of 0.3% by mass, and had a volume average primary particle size of 0.1 μm and a weight average molecular weight. (Mw) 20
10,000, number average molecular weight (Mn) 91,000, Mw / Mn =
2.2. Fine resin particles having a softening point (Tsp) of 230 ° C and a glass transition temperature (Tg) of 110 ° C were obtained. The resin fine particles azeotroped with water in an emulsified state, and the residual monomer content was 510 ppm.

Next, 100 parts of the ferrite core material particles and 2 parts of the resin fine particles were charged into a high-speed stirring mixer equipped with stirring blades.
The mixture was stirred and mixed at 120 ° C. for 30 minutes, and a resin-coated carrier having a volume average particle diameter of 61 μm was obtained using the action of mechanical impact. [Production of Developer] Each of the colored particles to which the external additive was added and the carrier were mixed to prepare a developer having a toner concentration of 6% by mass. These colored particles 1 to 12 and comparative colored particles 1 and 2 are referred to as developers 1 to 12 and comparative developers 1 and 2, respectively. (Production of photoreceptor) Polyamide resin Amilan CM-800
30 g of 0 (manufactured by Toray Industries, Inc.) was charged into a mixed solvent of 900 ml of methanol and 100 ml of 1-butanol, and dissolved by heating at 50 ° C. This liquid was applied on a cylindrical aluminum conductive support having an outer diameter of 60 mm and a length of 360 mm,
A thick intermediate layer was formed.

Next, 10 g of a silicone resin KR-5240 (manufactured by Shin-Etsu Chemical Co., Ltd.) was dissolved in 1000 ml of t-butyl acetate, and Y-TiOPc (Japanese Patent Application Laid-Open No. Sho 64-17066) was added thereto.
No. 1) mixed with 10 g and mixed with a sand mill.
After time dispersion, a coating solution for the charge generation layer was obtained. This liquid was used to coat the intermediate layer to form a 0.3 μm thick charge generation layer.

Next, 150 g of CTM (T-1: N- (4-methylphenyl) -N- {4- (β-phenylstyryl) phenyl} -p-toluidine) and a viscosity average molecular weight of 2
200 g of 10,000 polycarbonate resin Iupilon Z-200 (manufactured by Mitsubishi Gas Chemical Co., Ltd.) was added to 1,2-dichloroethane 10
The solution was dissolved in 00 ml to obtain a charge transport layer coating solution. The solution was applied on the charge generation layer using a circular slide hopper, and dried at 100 ° C. for 1 hour to form a charge transport layer having a thickness of 22 μm. Thus, a photoreceptor (P1) on which the intermediate layer, the charge generation layer, and the charge transport layer were formed was obtained.

Next, a CTM was placed on the surface of the photoreceptor (P1).
(T-1) 30 g of a polycarbonate resin Iupilon Z-800 having a viscosity average molecular weight of 80,000 (manufactured by Mitsubishi Gas Chemical Company) 50 g of a polycarbonate resin was treated with 1,2-dichloroethane 1
Using a coating solution dissolved in 000 ml, coating was performed on the charge transport layer with a circular slide hopper, and then 100
After drying at 1 ° C. for 1 hour, an overcoat layer having a thickness of 5 μm was formed to obtain a photoreceptor (P2).

A commercially available digital copying machine (Konica Siti
os 7030) with a photoreceptor (P2) mounted on a remodeled machine, under a high-temperature and high-humidity environment (temperature 33 ° C, relative humidity 80%), a real-life test to continuously form 300,000 images with a pixel rate of 15%. The following evaluation was performed. <Evaluation> Slippage Toner was evaluated by the number of sheets that were detected as image stains by toner slipping from the cleaning device onto the photoreceptor in the white background of the image.
Generally, when the fluidity of the toner is significantly reduced, slippage occurs.・ Environmental dependency of image density The maximum image density of the solid image area was measured with a Macbeth reflection densitometer. High temperature and high humidity environment (temperature 33 ° C, relative humidity 8
0%) and low temperature and low humidity environment (temperature 10 ° C, relative humidity 20)
%) Is less than 0.05 when the difference between the image densities is less than 0.05
0.1 was rated as ○, and exceeding 0.1 was rated as x. -Density of 10% halftone dot For a 10% halftone dot image portion of 20 mm x 20 mm, the relative image density to a white background portion was measured using a Macbeth reflection densitometer "RD-918". Evaluation of 10% halftone dot density
This was performed to evaluate the reproducibility of dots and the reproducibility of halftones. If the density change is within 0.10, it can be said that the image quality change is small and there is no problem. -Line width The line width of the line image corresponding to the image signal of the two-dot line was measured by a print evaluation system "RT2000" (manufactured by Yarman Corporation). Both the line width of the first formed image and the line width of the 20,000-th formed image are 20
If it is 0 μm or less and the change in line width is less than 10 μm, it can be said that fine line reproducibility is not a problem. -Character crushing Three-point and five-point character images were formed and evaluated according to the following criteria.

◎ ・ ・ ・ 3 points and 5 points are clear and easily readable ○ ・ ・ ・ 3 points are partially unreadable characters and 5 points
Points are clear and easily legible. × ・ ・ ・ 3 points are almost illegible, and 5 points are partially or totally illegible. ・ Fogging situation Non-image area with Macbeth densitometer Was measured relative to the white background density.

・ ・ ・: Less than 0.002 ・ ・ ・: 0.002 to 0.005 ×: a value exceeding 0.005 Table 4 shows the obtained results.

[0236]

[Table 4]

As is clear from Table 4, Examples 1 to 12
Is a good result in any of the evaluations, and it can be seen that an excellent image can be obtained. However, it can be seen that in a comparative example in which the ratio of rutile-type titanium oxide to anatase-type titanium oxide in the hydrophobic titanium oxide is not in the range of 2:98 to 45:55 by mass, a sufficiently satisfactory image cannot be obtained.

[0238]

According to the toner of the present invention, the fluidity is excellent, the charge distribution is uniform, the environment is less dependent, the detachment of external additives is less, and the carrier and the triboelectric charging member are not contaminated. Has a remarkably excellent effect that a stable image can be obtained.

[Brief description of the drawings]

FIG. 1A is an explanatory diagram showing a projected image of a toner particle having no corner, and FIGS. 1B and 1C are explanatory diagrams showing a projected image of a toner particle having a corner.

FIG. 2 is a cross-sectional view illustrating an example of a fixing device.

[Explanation of symbols]

 Reference Signs List 8 recording material 10 heating roller 11 core metal 12 coating layer 13 heating member 20 pressure roll 21 core metal 22 coating layer T toner image formed on recording material

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Tsuyoshi Uchida 2970 Ishikawacho, Hachioji-shi, Tokyo Konica Corporation F-term (reference) 2H005 AA06 AA08 AB06 CA14 CA26 CB07 EA05 EA07 EA10

Claims (15)

[Claims] An electrostatic charge comprising, as an external additive, hydrophobic titanium oxide having rutile-type titanium oxide and anatase-type titanium oxide in the same particle and having a treatment layer surface-treated with a silane coupling agent. An image developing toner, wherein the hydrophobic titanium oxide has a mass ratio of rutile-type titanium oxide to anatase-type titanium oxide of 2:98 to 4 by mass.
A toner for developing an electrostatic image, wherein the toner is in the range of 5:55. 2. The hydrophobic titanium oxide has a primary particle size of 0.1.
01 to 0.1 μm and a BET specific surface area of 90 to
^{2. The} toner for developing an electrostatic image according to claim 1, wherein the toner has a density of 220 m ² / g. 3. The hydrophobic titanium oxide has a degree of hydrophobicity of 30 to 30.
85%, carbon content is 2-8%, by ESCA surface analysis,
3. The electrostatic image developing toner according to claim 1, wherein an exposure amount of the titanium element is 0.01 to 5%. 4. The percentage of toner particles having no corners is 50% by number.
The number variation coefficient in the number particle size distribution is 27
% Or less.
Item 7. The toner for developing an electrostatic image according to Item 1. 5. The method according to claim 1, wherein the proportion of toner particles having a shape factor in the range of 1.2 to 1.6 is 65% by number or more, and the variation coefficient of the shape coefficient is 16% or less. The toner for developing an electrostatic charge image according to claim 1. 6. The electrostatic image developing toner according to claim 1, wherein the toner is obtained by polymerizing at least a polymerizable monomer in an aqueous medium. 7. The method according to claim 1, wherein the resin particles are obtained by coagulating and fusing at least resin particles in an aqueous medium.
The toner for developing an electrostatic image according to any one of claims 1 to 4. 8. A toner obtained by salting out, aggregating, and fusing a composite resin particle obtained by a multi-stage polymerization method and a colorant particle, wherein the toner is released to a region other than the outermost layer of the composite resin particle. The toner for developing an electrostatic image according to claim 1, further comprising an agent. 9. An electrostatic charge containing, as an external additive, hydrophobic titanium oxide having rutile-type titanium oxide and anatase-type titanium oxide in the same particle and having a surface treated with a silane coupling agent. An image developing toner, wherein the ratio of toner particles having no corners is 50% by number or more, and the number variation coefficient in the number particle size distribution is 27% or less. An electrostatic image developing toner. 10. The toner according to claim 1, wherein the proportion of toner particles having a shape coefficient in the range of 1.2 to 1.6 is 65% by number or more, and the variation coefficient of the shape coefficient is 16% or less. The toner for developing an electrostatic image according to claim 9. 11. The electrostatic image developing toner according to claim 9, wherein the toner is obtained by polymerizing at least a polymerizable monomer in an aqueous medium. 12. The electrostatic image developing toner according to claim 9, wherein the toner is obtained by aggregating and fusing at least resin particles in an aqueous medium. 13. A toner obtained by salting out, aggregating, and fusing a composite resin particle obtained by a multistage polymerization method and a colorant particle, wherein the toner is released to a region other than the outermost layer of the composite resin particle. The electrostatic image developing toner according to claim 9, further comprising an agent. 14. The particle diameter of toner particles is D (μm).
When the natural logarithm lnD is plotted on the horizontal axis, this horizontal axis is 0.2
Shows the number-based particle size distribution divided into multiple classes at three intervals
Of toner particles contained in the most frequent class in the histogram
Relative frequency (m ₁) And the most frequent class next to the mode
The relative frequency (m_Two) And sum
(M) is at least 70%.
14. The toner for developing an electrostatic image according to any one of items 13 to 13. 15. A step of forming an electrostatic image on an electrostatic image carrier, a step of developing the electrostatic image with a developer containing an electrostatic image developing toner to form a toner image, and the toner image. 15. An image forming method comprising a step of transferring a toner onto a transfer member, wherein the toner for developing an electrostatic image is used as the toner.
An image forming method, comprising using the toner for developing an electrostatic image according to any one of the preceding claims.