JP2010032607A - Toner for electrostatic charge image development and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner for electrostatic charge image development, the toner having a broad fixing latitude from a high temperature side to a low temperature side and stable thermal characteristics preventing a fixed image from so-called tacking, and also to provide an image forming method by which a high quality and stable image with high picture quality is formed by using the above toner. <P>SOLUTION: The toner for electrostatic charge image development contains at least a binder resin, a colorant and a release agent, wherein the release agent contains an ester wax having an acid value and at least one kind of fatty acid amide expressed by general formula (1):R<SB>1</SB>CONHR<SB>2</SB>. In the formula, R<SB>1</SB>is selected from alkyl groups or alkenyl groups having 12 to 50 carbon atoms; and R<SB>2</SB>is selected from a hydrogen atom or alkyl groups or alkenyl groups having 12 to 50 carbon atoms. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electrostatic image developing toner and an image forming method used when developing an electrostatic latent image formed by an electrophotographic method or an electrostatic recording method with a developer.

  A method of visualizing image information through an electrostatic charge image such as electrophotography is currently used in various fields. In electrophotography, an electrostatic charge image is formed on a photoreceptor by charging and exposure processes, and the electrostatic latent image is developed with a developer containing a toner for developing an electrostatic charge image (hereinafter simply referred to as toner). It is visualized through a transfer and fixing process.

  The developer used here includes a two-component developer composed of a toner and a carrier, and a one-component developer using a magnetic toner or a non-magnetic toner alone. The toner manufacturing method is a kneading and pulverizing method in which a thermoplastic resin is melt kneaded with a release agent such as a colorant and wax, and a charge control agent as necessary, cooled, finely pulverized, and further classified. Although used, polymerized toner has been proposed as a production method from the viewpoint of controlling the shape of the toner and reducing the particle size. A polymerized toner is a suspension in which a colorant, a release agent such as wax, and a charge control agent as necessary are dissolved or dispersed in a monomer constituting a thermoplastic resin, and dispersed in a toner particle diameter and polymerized in an aqueous phase. There is known an emulsion polymerization aggregation method in which a resin fine particle dispersion is prepared by a polymerization method, emulsion polymerization, etc., and mixed with a colorant dispersion in which a colorant is dispersed in a medium such as water, and then agglomerated and heat-fused into a toner. Yes.

  In particular, the latter not only makes it easy to control the toner shape and diameter, but also allows the structure of the toner particles to be freely controlled, thereby enabling higher resolution and clearer image reproduction.

  In recent years, in order to reduce energy consumption in an image forming apparatus, a technique capable of fixing at a lower temperature is desired. Therefore, a method has been proposed in which the energization of the fixing device is stopped except during use. When this method is used, the temperature of the fixing device needs to be instantaneously increased to the use temperature along with the energization. For this purpose, it is desirable to reduce the heat capacity of the fixing device. However, as a result, the temperature of the fixing device becomes larger than that of the conventional case. In other words, the temperature overshoot of the fixing device after the start of energization increases, and the temperature drop also increases due to the passing of paper.

  Further, when the paper smaller than the width of the fixing device is continuously passed, the temperature difference between the paper passing portion and the non-paper passing portion of the fixing device becomes large. Particularly in the case of high-speed copying machines and printers, the power capacity tends to be insufficient, and the above phenomenon is likely to occur. Accordingly, there is a need for a toner for developing an electrostatic charge image that is fixed at a lower temperature and does not generate an offset even in a higher temperature region and has a wide fixing temperature latitude.

  In a high-speed machine, a large amount of images must be formed in a short time, and a large amount of fixed images are often stacked on a paper discharge tray, or fixed images are often stacked. These tend to cause so-called tacking in which the images or the image and the white paper are bonded to each other depending on the surrounding temperature and the weight of the stacked recording paper. In order to prevent this, there is a demand for a toner for developing an electrostatic image that is not only resistant to mechanical and thermal stresses in copiers and printers, but also resistant to mechanical and thermal stresses after image formation. Yes.

  Furthermore, in order to lower the toner fixing temperature, it is necessary to design a resin that exhibits a sharp melting behavior with respect to the temperature by lowering the glass transition temperature and softening point of the binder resin constituting the toner (for example, Patent Document 1). However, this is disadvantageous in order to prevent blocking during toner storage.

  On the other hand, in order to prevent offset on the high temperature side, optimization of the molecular weight distribution of the resin, optimization of the release agent, etc. are extremely important. For tacking, a resin having a high glass transition temperature is better. desirable. However, this tends to deteriorate the low-temperature fixability.

As described above, it is difficult to achieve all the performance to be retained by the toner, and it has a wide fixing latitude from the high temperature side to the low temperature side, and has a stable thermal characteristic in which the fixed image does not cause so-called tacking. It is not easy to provide a toner for use.
JP-A-9-204071

  An object of the present invention is to provide a toner for developing an electrostatic image having a wide fixing latitude from a high temperature side to a low temperature side and having a stable thermal characteristic in which a fixed image does not cause so-called tacking.

  Another object of the present invention is to provide an image forming method that can stably form an image with high image quality and high quality by using this.

  As a result of intensive studies by the inventors, it has been found that the object of the present invention can be achieved by adopting the following configuration.

(1)
In an electrostatic charge image developing toner containing at least a binder resin, a colorant and a release agent, the release agent contains an ester wax having an acid value and at least one fatty acid amide represented by the following general formula (1). A toner for developing an electrostatic charge image.

General formula (1) R ₁ CONHR ₂
(In the formula, R ₁ is selected from an alkyl group or alkenyl group having 12 to 50 carbon atoms, and R ₂ is selected from a hydrogen atom, an alkyl group having 12 to 50 carbon atoms, or an alkenyl group.)
(2)
The toner for developing an electrostatic charge image according to (1), wherein the fatty acid amide in the release agent is 1 to 20% by mass of the total toner mass.

(3)
The toner for developing an electrostatic charge image according to (1), wherein the ester wax having an acid value in the release agent comprises a compound having at least one carboxyl group and a long-chain alkyl alcohol.

(4)
The toner for developing an electrostatic charge image according to (3), wherein the release agent contains a partially esterified product and has an acid value of 3 to 20 mgKOH / g.

(5)
An image forming method, wherein the toner for developing an electrostatic charge image according to any one of (1) to (4) is used for contact heating and fixing.

  According to the present invention, there is provided a toner for developing an electrostatic image having a wide fixing latitude from a high temperature side to a low temperature side and having a stable thermal characteristic in which a fixed image does not cause so-called tacking.

  Another object of the present invention is to provide an image forming method that can stably form an image with high image quality and high quality by using this.

  The present invention will be described in detail.

  First, the reason why the effect of the present invention can be obtained by the configuration of the present invention is considered as follows.

  The fatty acid amide compound of the present invention, an ester wax having an acid value, a carboxyl group in a binder resin and the like form hydrogen bonds at a low temperature, but the hydrogen bonds are dissociated at a high temperature. For this reason, in the heating state at the time of fixing, the hydrogen bond is in a dissociated state, the wax has a low viscosity, and has a sufficient elution rate and releasability to prevent low temperature fixing and high temperature offset. On the other hand, after image formation after fixing, a wax layer is formed on the surface of the image, and hydrogen bonds are formed in the wax layer, so that it has a sufficiently high melting point and hardness, and particularly has the effect of preventing tacking and maintaining a stable image. Have.

[Fatty acid amide compound of the present invention]
In the present invention, the fatty acid amide represented by the general formula (1) includes the following compounds.

Examples of the fatty acid amide in which R _{2 in the} general formula (1) is a hydrogen atom include lauric acid amide, myristic acid amide, palmitic acid amide, behenic acid amide, oleic acid amide, and erucic acid amide.

Examples of the fatty acid amide compound in which R _{2 in the} general formula (1) is an alkyl group having 12 to 50 carbon atoms or an alkenyl group include N-stearyl erucamide, N-oleyl palmitamide, N-behenyl behenic acid amide and the like. Can be mentioned.

  The content of the fatty acid amide compound is preferably 1 to 20% by mass of the total toner mass. More preferably, it is 2-15 mass%. It is 2.5-8 mass% as conditions used suitably.

[Ester wax of the present invention]
Examples of the long-chain alkyl alcohol of monocarboxylic acid include behenyl behenate, stearyl stearyl, stearyl behenate, behenyl stearyl, and the like.

  Examples of the long-chain alcohol ester of dicarboxylic acid include stearyl alcohol ester, behenyl alcohol ester of itaconic acid, stearyl alcohol ester of adipic acid, behenyl alcohol ester and the like.

  Examples of the long-chain alcohol ester of tricarboxylic acid include stearyl alcohol triester of citric acid, behenyl alcohol triester, stearyl alcohol ester of aconitic acid, behenyl alcohol ester, and the like.

  As the partially esterified product, a target acid value of 3 to 20 mgKOH / g can be obtained by adjusting the ratio of the alcohol component and the acid component in the ester wax during the esterification reaction.

  The fatty acid amide compound of the present invention is used in combination with an ester wax. For example, even if both are mixed, they may be included in the same toner as separate particles. Since the fatty acid amide of the present invention is highly polar, when added in a large amount, it is compatible with the binder resin of the toner, lowering the glass transition temperature and softening point of the binder resin, and therefore there is no sufficient effect of preventing high temperature offset. In addition, the effect of preventing tacking also decreases. On the other hand, if the addition amount is small, hydrogen bonds are not sufficiently formed and tacking prevention cannot be expected.

  In addition, as a mold release agent, usual mold release agents, for example, low molecular weight polyolefins such as polyethylene, polypropylene, polybutene, silicones having a softening point by heating, oleic acid amide, erucic acid amide, ricinoleic acid amide, stearic acid amide Fatty acid amides such as, plant waxes such as carnauba wax and rice wax, animal waxes such as beeswax, montan wax, ceresin, paraffin wax, Fischer-Tropsch wax and other minerals and petroleum waxes, etc. Good.

  The content of the whole release agent including the ester wax and the usual release agent is preferably 1 to 30 parts by mass, particularly 5 to 20 parts by mass with respect to the whole toner. Moreover, the preferable content rate of ester wax is 70-99 mass% of the whole mold release agent, More preferably, 80-99 mass% is good.

[Production of toner]
Next, a method for producing the toner of the present invention will be described.

  The toner of the present invention is an electrostatic charge image developing toner obtained by aggregating at least a binder resin, a release agent and a colorant, and heat-sealing. Those having a shell structure are preferred.

  Therefore, hereinafter, a method for producing a toner having a core / shell structure will be mainly described.

  The core particles of the toner having a core / shell structure are colored composite resin particles having a multilayer structure prepared by a suspension polymerization method, and composite resin particles having a multilayer structure called a multistage polymerization method, particularly emulsion polymerization. It is obtained by agglomerating and fusing together with agent particles (or colored resin particles) in the presence of an aggregating agent. The core particles formed from the composite resin particles and colored resin particles thus formed are further subjected to a shelling operation using a separately prepared resin particle dispersion, and at least one layer of shell is formed on the surface of the core particles. Form. In this manner, toner particles in which a shell made of resin fine particles is formed can be produced by performing a shelling operation on the surface of the core particles.

  Further, the toner of the present invention having a core / shell structure is usually prepared by adding an external additive to the generated shell surface.

  The mass ratio of the core particle and the shell (which may be a single layer or a plurality of layers) of the toner of the present invention is preferably 5 to 30% by mass with respect to the mass of the core particle.

  Next, a method for producing the toner of the present invention will be described.

The toner of the present invention is produced, for example, through the following steps.
(1) Dissolution / dispersion step for dissolving or dispersing in radical polymerizable monomer (2) Polymerization step for preparing a dispersion of resin fine particles (3) Aggregation and fusion of resin fine particles and colorant particles in an aqueous medium Aggregation / fusion process for obtaining core particles (associated particles) by deposition (4) First aging process for aging associated particles by heat energy to adjust the shape (5) In core particle (associate particles) dispersion Shell forming step of adding shell resin particles and aggregating and fusing the shell particles on the surface of the core particles to form core-shell structure toner particles (6) Thermal energy of the core-shell structure toner particles The second aging step for adjusting the shape of the toner particles having a core / shell structure (7) The toner particles are solid-liquid separated from the cooled toner particle dispersion, and the surfactant is removed from the toner particles. Cleaner to remove (8) Drying step of drying the washed treated toner particles also after the drying step if necessary,
(9) A step of adding an external additive to the dried toner particles as necessary.

  Next, the above process will be described in detail.

  When the toner of the present invention is manufactured, first, resin particles and colorant particles are associated and fused to produce core particles serving as a core. Next, the resin particles for the shell are added to the core particle dispersion, and the resin particles are aggregated and fused on the surface of the core particles to coat the surface of the core particles to produce toner particles having a core / shell structure. To do. As described above, the toner of the present invention is prepared by adding resin particles for a shell to a core particle dispersion prepared by various production methods and fusing the core resin particles to the core particles. is there.

  The shape of the core particles constituting the toner of the present invention is controlled, for example, by controlling the heating temperature in the aggregation / fusion process and the heating temperature and time in the first aging process. That is, by controlling the heating temperature to be lower in the aggregation / fusion process, the progress of the fusion between the resin particles is suppressed and the modification is promoted. Further, it is possible to deform the core particles and control the shape by lowering the heating temperature and shortening the time in the first aging step.

  Time control in the first aging step is the most effective for shape control. Since the ripening step is intended to adjust the circularity of the associated particles, when the time is increased, the shape of the associated particles becomes a shape close to a true sphere.

  Next, a method for producing a toner capable of producing the toner of the present invention described above will be described in detail.

  The core particles constituting the toner of the present invention may be prepared by, for example, dissolving or dispersing a release agent component in a polymerizable monomer that forms a resin, and then mechanically dispersing fine particles in an aqueous medium. A method of salting out and fusing the composite resin fine particles formed through the step of polymerizing the polymerizable monomer and the colorant particles is used. When the release agent component is dissolved in the polymerizable monomer, the release agent component may be dissolved or melted or dissolved.

  As a method for producing the core particles, a step of salting out and fusing the composite resin fine particles containing the resin obtained by the multistage polymerization method and the colorant particles is preferably used. Specifically, the following methods are mentioned.

[Dissolution / dispersion process]
This step is a step of preparing a radical polymerizable monomer solution in which a release agent compound is mixed by dissolving a release agent compound in a radical polymerizable monomer.

[Polymerization process]
In a preferred example of this polymerization step, a radical polymerizable monomer solution in which the mixture of the long-chain alkyl alcohol is dissolved or dispersed in an aqueous medium containing a surfactant having a critical micelle concentration (CMC) or less is contained. Addition and mechanical energy are applied to form droplets, and then a water-soluble radical polymerization initiator is added to proceed the polymerization reaction in the droplets. An oil-soluble polymerization initiator may be contained in the droplet. In such a polymerization process, mechanical energy is imparted and forcedly emulsified (formation of droplets) is essential. Examples of the mechanical energy applying means include strong stirring such as homomixer, ultrasonic wave, and manton gorin or ultrasonic vibration energy applying means.

  By this polymerization step, resin fine particles containing a release agent and the like and a binder resin are obtained. Such resin fine particles may be colored fine particles or non-colored fine particles. The colored resin fine particles can be obtained by polymerizing a monomer composition containing a colorant. In addition, when using uncolored resin fine particles, a dispersion of colorant particles is added to the dispersion of resin fine particles in the aggregation / fusion process described later to melt the resin fine particles and the colorant fine particles. By applying it, toner particles can be obtained.

[Aggregation / fusion process] (including the first aging process)
As a method of aggregation and fusion in the fusion step, a salting out and fusion method using resin fine particles (colored or non-colored resin fine particles) obtained in the polymerization step is preferable. Further, in the aggregation / fusion step, the internal additive particles such as the release agent particles and the charge control agent can be aggregated and fused together with the resin fine particles and the colorant particles.

  The “aqueous medium” in the agglomeration / fusion step is one in which the main component (50% by mass or more) is made of water. Examples of components other than water include organic solvents that dissolve in water, such as methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, and tetrahydrofuran.

  The colorant particles can be prepared by dispersing the colorant in an aqueous medium. The dispersion treatment of the colorant is performed in a state where the surfactant concentration is set to a critical micelle concentration (CMC) or more in water. The disperser used for the dispersion treatment of the colorant is not particularly limited, but preferably an ultrasonic disperser, a mechanical homogenizer, a pressure disperser such as a manton gorin or a pressure homogenizer, a sand grinder, a Getzmann mill, a diamond fine mill, or the like. A medium type disperser is mentioned. Moreover, as a surfactant used, the same thing as the above-mentioned surfactant can be mentioned. The colorant (fine particles) may be surface-modified. In the surface modification method of the colorant, the colorant is dispersed in a solvent, the surface modifier is added to the molecular weight solution, and the system is reacted by raising the temperature. After completion of the reaction, the colorant is filtered off, washed and filtered with the same solvent, and dried to obtain a colorant treated with the surface modifier.

  The salting out and fusing method, which is a preferred agglomeration and fusing method, is a salting out method comprising an alkali metal salt, an alkaline earth metal salt, a trivalent salt, or the like in water in which resin fine particles and colorant particles are present. An agent is added as an aggregating agent having a critical agglomeration concentration or higher, and then salting-out proceeds by heating to a temperature not lower than the glass transition temperature of the resin fine particles and not lower than the melting peak temperature (° C.) of the mixture. At the same time, it is a process of fusing. Here, the alkali metal salt and the alkaline earth metal salt which are salting-out agents include lithium, potassium, sodium and the like as the alkali metal, and examples of the alkaline earth metal include magnesium, calcium, strontium and barium. Preferably, potassium, sodium, magnesium, calcium, and barium are used.

  When agglomerating and fusing are performed by salting out and fusing, it is preferable to make the time allowed to stand after adding the salting out agent as short as possible. The reason for this is not clear, but there are problems that the aggregation state of the particles fluctuates depending on the standing time after salting out, the particle size distribution becomes unstable, and the surface property of the fused toner fluctuates. appear. The temperature for adding the salting-out agent needs to be at least the glass transition temperature of the resin fine particles. The reason for this is that if the temperature at which the salting-out agent is added is equal to or higher than the glass transition temperature of the resin fine particles, the salting-out / fusion of the resin fine particles proceeds rapidly, but the particle size cannot be controlled, which is large. There arises a problem that particles having a particle size are generated. Although the range of this addition temperature should just be below the glass transition temperature of resin, generally it is 5-55 degreeC, Preferably it is 10-45 degreeC.

  Further, the salting-out agent is added at a temperature not higher than the glass transition temperature of the resin fine particles, and then the temperature is raised as quickly as possible to a temperature not lower than the glass transition temperature of the resin fine particles and not lower than the melting peak temperature (° C.) of the mixture. Heat to. The time until this temperature rise is preferably less than 1 hour. Further, although it is necessary to quickly raise the temperature, the rate of temperature rise is preferably 0.25 ° C./min or more. The upper limit is not particularly clear, but if the temperature is increased instantaneously, salting out proceeds rapidly, so that there is a problem that it is difficult to control the particle size, and 5 ° C./min or less is preferable. By this fusion step, a dispersion of associated particles (core particles) obtained by salting out and fusing resin fine particles and arbitrary fine particles is obtained.

[Shelling process] (including second aging process)
In the shelling step, the resin particle dispersion for the shell is added to the core particle dispersion to agglomerate and fuse the resin particles for the shell onto the surface of the core particles, and the resin particles for the shell are coated on the surface of the core particles. To form toner particles.

  Specifically, the core particle dispersion is added with a dispersion of resin particles for shells while maintaining the temperature in the above-described aggregation / fusion process and the first aging process, and it takes several hours while continuing heating and stirring. Then, the resin particles for shell are slowly coated on the surface of the core particles to form toner particles. The heating and stirring time is preferably 1 hour to 7 hours, particularly preferably 3 hours to 5 hours. Then, when the toner particles have reached a predetermined particle size due to shelling, a stopper such as sodium chloride is added to stop the particle growth, and then the resin particles for the shell adhered to the core particles are fused. Continue to stir for several hours. In the shelling step, a shell having a thickness of 10 to 500 nm is formed on the core particle surface. In this way, resin particles are fixed on the surface of the core particles to form a shell, and rounded toner particles having a uniform shape are formed.

[Cooling process]
This step is a step of cooling (rapid cooling) the toner particle dispersion. As a cooling treatment condition, cooling is performed at a cooling rate of 1 to 20 ° C./min. The cooling treatment method is not particularly limited, and examples thereof include a method of cooling by introducing a refrigerant from the outside of the reaction vessel, and a method of cooling by directly introducing cold water into the reaction system.

[Solid-liquid separation and washing process]
In the solid-liquid separation / washing step, the solid-liquid separation process for solid-liquid separation of the toner particles from the dispersion of the toner particles cooled to a predetermined temperature in the above-described step, and the solid-liquid separated toner cake (in a wet state) A cleaning process is performed to remove deposits such as a surfactant and a salting-out agent from an aggregate obtained by agglomerating certain toner particles in a cake form. Here, the filtration method is not particularly limited, such as a centrifugal separation method, a vacuum filtration method using Nutsche or the like, a filtration method using a filter press or the like.

[Drying process]
In this step, the washed toner cake is dried to obtain dried toner particles. Examples of dryers used in this process include spray dryers, vacuum freeze dryers, vacuum dryers, etc., stationary shelf dryers, mobile shelf dryers, fluidized bed dryers, rotary dryers It is preferable to use a stirring dryer or the like. The moisture of the dried toner particles is preferably 5% by mass or less, more preferably 2% by mass or less. In addition, when the toner particles subjected to the drying treatment are aggregated by weak interparticle attractive force, the aggregate may be crushed. Here, as the crushing treatment apparatus, a mechanical crushing apparatus such as a jet mill, a Henschel mixer, a coffee mill, or a food processor can be used.

[External process]
This step is a step of preparing a toner by mixing the dried toner particles with an external additive as necessary.

  As an external additive mixing device, a mechanical mixing device such as a Henschel mixer or a coffee mill can be used.

The average particle diameter of the toner of the present invention is preferably 2.5 to 7.0 μm in terms of volume-based median particle diameter (D ₅₀ ). The median particle size (D ₅₀ ) on the volume basis is measured and calculated using a device in which a computer system for data processing (Beckman Coulter, Inc.) is connected to “Coulter Multisizer 3” (Beckman Coulter, Inc.). can do.

  As a measurement procedure, 0.02 g of toner is blended with 20 ml of a surfactant solution (for example, a surfactant solution obtained by diluting a neutral detergent containing a surfactant component 10 times with pure water for the purpose of dispersing the toner). After that, ultrasonic dispersion is performed for 1 minute to prepare a toner dispersion. This toner dispersion is injected into a beaker containing ISOTON II (manufactured by Beckman Coulter, Inc.) in a sample stand with a pipette until the measured concentration is 5 to 10%, and the measuring machine count is set to 30000. To do. The aperture diameter of the Coulter Multisizer was 100 μm.

  The toner of the present invention can be used as a black toner or a color toner.

  Next, the compounds (binder resin, colorant, charge control agent, external additive, lubricant) constituting the toner of the present invention will be described.

[Binder resin]
As the polymerizable monomer constituting the binder resin, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-chlorostyrene, 3,4-dichloro are used. Styrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn -Styrene or styrene derivatives such as decylstyrene, pn-dodecylstyrene, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-methacrylate Octyl, 2-ethylhexyl methacrylate, stearyl methacrylate Methacrylic acid ester derivatives such as lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, acrylic Acrylates such as isobutyl acid, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, phenyl acrylate, olefins such as ethylene, propylene, isobutylene, vinyl chloride, vinylidene chloride, Halogenated vinyls such as vinyl bromide, vinyl fluoride and vinylidene fluoride, vinyl esters such as vinyl propionate, vinyl acetate and vinyl benzoate, vinyl methyl ether, vinyl ethyl ether Vinyl ethers such as ether, vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone, vinyl hexyl ketone, N-vinyl compounds such as N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone, vinyl naphthalene, vinyl pyridine, etc. Examples include vinyl compounds, 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 combination of monomers having an ionic dissociation group as the polymerizable monomer constituting the resin. For example, it has a substituent such as a carboxyl group, a sulfonic acid group, a phosphoric acid group as a constituent group of the monomer, specifically, acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumar Acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester, styrene sulfonic acid, allyl sulfosuccinic acid, 2-acrylamido-2-methylpropane sulfonic acid, acid phosphooxyethyl methacrylate, 3-chloro-2-acid phosphooxy And propyl methacrylate.

  Furthermore, multifunctional 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. It is also possible to use a crosslinkable resin by using a functional 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. Examples of the oil-soluble polymerization initiator include 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carboxyl). Nitriles), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, azo- or diazo-based 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- t-butylperoxycyclohexyl) propane, tris- Peroxide polymerization initiator or a peroxide such as t- butylperoxy) triazine and the like polymeric initiator having a side chain.

  Moreover, when using an emulsion polymerization method, a water-soluble radical polymerization initiator can be used. Examples of the water-soluble polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate, azobisaminodipropane acetate, azobiscyanovaleric acid and its salts, hydrogen peroxide and the like.

[Colorant]
As the colorant used in the present invention, a known inorganic or organic colorant can be used. Specific colorants are shown below.

  Examples of the black colorant include carbon black such as furnace black, channel black, acetylene black, thermal black, and lamp black, and magnetic powder such as magnetite and ferrite.

  Examples of the colorant for magenta or red 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 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. And CI Pigment Red 222.

  Examples of the colorant for orange or yellow include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. And CI Pigment Yellow 138.

  Examples of the colorant for green or cyan 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 15; 4, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. Pigment blue 62, C.I. I. Pigment blue 66, C.I. I. And CI Pigment Green 7.

  These colorants may be used alone or in combination of two or more as required. The addition amount of the colorant is set in the range of 1 to 30% by mass, preferably 2 to 20% by mass with respect to the whole toner.

[Charge control agent]
A charge control agent can be added to the toner of the present invention as necessary. As the charge control agent, known compounds can be used. Specifically, nigrosine dyes, metal salts of naphthenic acid or higher fatty acids, alkoxylated amines, quaternary ammonium salt compounds, azo metal complexes, salicylic acid Examples thereof include a metal salt or a metal complex thereof. Examples of the metal contained include Al, B, Ti, Fe, Co, and Ni. Particularly preferred as the charge control agent is a metal complex compound of a benzylic acid derivative. In addition, when the content of the charge control agent is preferably 0.1 to 20.0% by mass with respect to the whole toner, good results can be obtained.

(External additive)
The toner of the present invention may be prepared by adding a small diameter external additive and a large diameter external additive.

  This is because the flowability of the developer by the small-diameter external additive and the transferability by the large-diameter external additive provide an effect of suppressing the occurrence of image defects when the low-temperature fixing toner is used for a long time. .

  As the small-diameter external additive, those having a number average primary particle diameter of 10 to 60 nm are preferable, and specific examples thereof include silica, titania, alumina, strontium titanate particles and the like.

  As the large-diameter external additive, those having a number average primary particle diameter of 80 nm to 1 μm are preferable, and specific examples thereof include general lubricants, organic fine particles, and inorganic fine particles having the above particle diameters.

  Examples of the lubricant include metal salts of higher fatty acids. Specific examples of the metal salts of such higher fatty acids include zinc stearate, aluminum stearate, copper stearate, magnesium stearate, calcium stearate, and the like; zinc oleate, manganese oleate, iron oleate, olein Oleic acid metal salts such as acid copper and magnesium oleate; palmitate metal salts such as zinc palmitate, copper palmitate, magnesium palmitate and calcium palmitate; linoleic acid metal salts such as zinc linoleate and calcium linoleate; ricinol Examples include ricinoleic acid metal salts such as zinc acid and calcium ricinoleate.

  Examples of the organic particles include particles such as polystyrene, polymethyl methacrylate, styrene-methyl methacrylate copolymer, benzoguanamine, and melamine.

  As the large-sized inorganic particles, a dope such as titanium-doped silica is preferably used, and these inorganic particles are preferably hydrophobized with a silane coupling agent, a titanium coupling agent, or the like.

  The addition amount of the external additive is preferably 0.1 to 10.0% by mass with respect to the whole toner. As a method for adding the external additive, various known mixing apparatuses such as a Turbuler mixer, a Henschel mixer, a Nauter mixer, and a V-type mixer can be used.

  The number average primary particle diameter of the external additive is specifically measured by the following method.

  A 30,000 times photograph of the toner is taken with a scanning electron microscope, and the photograph image is captured by a scanner. Image processing analyzer “LUZEX AP” (manufactured by Nireco) binarizes the external additive present on the toner surface of the photographic image, and calculates the horizontal ferret diameter for 100 external additives. The average value is taken as the number average primary particle size. When the number average primary particle diameter of the external additive is small and exists as an aggregate on the toner surface, the particle diameter of the primary particles forming the aggregate is measured.

(Developer)
The toner of the present invention can be used as a one-component developer or a two-component developer. When used as a one-component developer, examples include a non-magnetic one-component developer or a magnetic one-component developer containing about 0.1 to 0.5 μm magnetic particles in a toner. be able to. Further, it can be mixed with a carrier and used as a two-component developer. In this case, conventionally known materials typified by iron-containing magnetic particles such as iron, ferrite, and magnetite can be used as the magnetic particles of the carrier, but ferrite particles or magnetite particles are particularly preferable. The magnetic particles preferably have a volume average particle diameter of 15 to 100 μm, more preferably 20 to 80 μm.

  The volume average particle diameter of the carrier can be measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by Sympathetic).

  The carrier is preferably a coating carrier in which magnetic particles are further coated with a resin, or a so-called resin dispersion type carrier in which magnetic particles are dispersed in a resin. The resin composition for coating is not particularly limited, and for example, olefin resin, styrene resin, styrene-acrylic resin, silicon resin, ester resin, or fluorine-containing polymer resin is used. In addition, the resin for constituting the resin-dispersed carrier is not particularly limited, and a known resin can be used. For example, a styrene-acrylic resin, a polyester resin, a fluorine resin, a phenol resin, or the like is used. be able to.

  The mixing ratio of the carrier and the toner is preferably in the range of carrier: toner = 1: 1 to 50: 1 by mass ratio.

(Image forming method)
The image forming method according to the present invention is a contact-type fixing method in which a toner image on a transfer material formed using the toner of the present invention is fixed by passing between heating members constituting a fixing device.

  Hereinafter, an image forming apparatus and a fixing apparatus used in the image forming method will be described.

  FIG. 1 shows an example of an image forming apparatus using a two-component developer using a cleaning blade as an image forming apparatus used in the image forming method of the present invention.

  In FIG. 1, 1Y, 1M, 1C and 1K are photosensitive members, 4Y, 4M, 4C and 4K are developing means, 5Y, 5M, 5C and 5K are primary transfer rolls as primary transfer means, and 5A is a secondary transfer. Secondary transfer rolls as means, 6Y, 6M, 6C and 6K are blade cleaning means, 7 is an intermediate transfer body unit, 24 is a heat roll type fixing device, and 70 is an intermediate transfer body.

  This image forming apparatus is called a tandem color image forming apparatus, and includes a plurality of sets of image forming units 10Y, 10M, 10C, and 10K, an endless belt-shaped intermediate transfer body unit 7 as a transfer unit, and a recording member P. An endless belt-shaped sheet feeding / conveying means 21 and a heat roll type fixing device 24 as a fixing means. A document image reading device SC is disposed above the main body A of the image forming apparatus.

  As one of the different color toner images formed on each photoconductor, an image forming unit 10Y that forms a yellow image includes a drum-shaped photoconductor 1Y as a first photoconductor, and a periphery of the photoconductor 1Y. A charging unit 2Y, an exposure unit 3Y, a developing unit 4Y, a primary transfer roll 5Y as a primary transfer unit, and a cleaning unit 6Y. An image forming unit 10M that forms a magenta image as another different color toner image is disposed around a drum-shaped photoconductor 1M as a first photoconductor, and the photoconductor 1M. A charging unit 2M, an exposure unit 3M, a developing unit 4M, a primary transfer roll 5M as a primary transfer unit, and a cleaning unit 6M. In addition, an image forming unit 10C that forms a cyan image as one of other different color toner images is disposed around the photoconductor 1C as a drum-type photoconductor 1C as a first photoconductor. The charging unit 2C, the exposure unit 3C, the developing unit 4C, the primary transfer roll 5C as the primary transfer unit, and the cleaning unit 6C are provided. Further, an image forming unit 10K that forms a black image as one of other different color toner images is disposed around a drum-shaped photosensitive member 1K as a first photosensitive member, and the photosensitive member 1K. It has a charging means 2K, an exposure means 3K, a developing means 4K, a primary transfer roll 5K as a primary transfer means, and a cleaning means 6K.

  The endless belt-like intermediate transfer body unit 7 has an endless belt-like intermediate transfer body 70 as an intermediate transfer endless belt-like second image carrier that is wound around a plurality of rolls and is rotatably supported.

  Each color image formed by the image forming units 10Y, 10M, 10C, and 10K is sequentially transferred onto the rotating endless belt-shaped intermediate transfer body 70 by the primary transfer rolls 5Y, 5M, 5C, and 5K, and is combined. A colored image is formed. A recording member P such as a sheet as a transfer material accommodated in the sheet feeding cassette 20 is fed by the sheet feeding / conveying means 21, passes through a plurality of intermediate rolls 22 A, 22 B, 22 C, 22 D, and a registration roll 23, and is secondary. A color image is transferred onto the recording member P at a time by being conveyed to a secondary transfer roll 5A as a transfer means. The recording member P to which the color image has been transferred is fixed by the heat roll type fixing device 24, is sandwiched by the paper discharge roll 25, and is placed on the paper discharge tray 26 outside the apparatus.

  On the other hand, after the color image is transferred to the recording member P by the secondary transfer roll 5A, the residual toner is removed by the cleaning unit 6A from the endless belt-shaped intermediate transfer body 70 in which the recording member P is separated by curvature.

  During the image forming process, the primary transfer roll 5K is always in pressure contact with the photoreceptor 1K. The other primary transfer rolls 5Y, 5M, and 5C are in pressure contact with the corresponding photoreceptors 1Y, 1M, and 1C, respectively, only during color image formation.

  The secondary transfer roll 5A comes into pressure contact with the endless belt-shaped intermediate transfer body 70 only when the recording member P passes through the secondary transfer roll 5A and secondary transfer is performed.

  Further, the housing 8 can be pulled out from the apparatus main body A through the support rails 82L and 82R.

  The housing 8 includes image forming units 10Y, 10M, 10C, and 10K, and an endless belt-shaped intermediate transfer body unit 7.

  The image forming units 10Y, 10M, 10C, and 10K are arranged in tandem in the vertical direction. An endless belt-shaped intermediate transfer body unit 7 is disposed on the left side of the photoreceptors 1Y, 1M, 1C, and 1K in the figure. The endless belt-shaped intermediate transfer body unit 7 includes an endless belt-shaped intermediate transfer body 70 that can be rotated by winding rolls 71, 72, 73, 74, and 76, primary transfer rolls 5Y, 5M, 5C, and 5K, and a cleaning unit. 6A.

  The image forming units 10Y, 10M, 10C, and 10K and the endless belt-shaped intermediate transfer body unit 7 are integrally pulled out from the main body A by the drawer operation of the housing 8.

  In this way, toner images are formed on the photoreceptors 1Y, 1M, 1C, and 1K by charging, exposure, and development, and the toner images of the respective colors are superimposed on the endless belt-shaped intermediate transfer body 70, and are collectively applied to the recording member P. The image is transferred and fixed by the fixing device 24 by pressing and heating. The photoreceptors 1Y, 1M, 1C, and 1K after transferring the toner image to the recording member P are cleaned with the cleaning device 6A to remove the toner remaining on the photoreceptor, and then the above charging, exposure, and development cycle. The next image formation is performed.

  The recording member (transfer material) used in the present invention is a support for holding a toner image, and is usually called an image support, a transfer body or transfer paper. Specifically, plain paper from thin paper to thick paper, high-quality paper, coated printing paper such as art paper and coated paper, commercially available Japanese paper and postcard paper, OHP plastic film, various transfer materials such as cloth However, it is not limited to these.

  FIG. 2 is a cross-sectional view showing an example of a fixing device (a type using a pressure roller and a heating roller) used in the present invention.

  The fixing device 10 shown in FIG. 2 includes a heating roller 71 and a pressure roller 72 in contact with the heating roller 71. In FIG. 2, reference numeral 17 denotes a toner image formed on the recording member (transfer material) P.

  The heating roller 71 has a coating layer 82 made of a fluororesin or an elastic body formed on the surface of the cored bar 81 and includes a heating member 75 made of a linear heater.

  The cored bar 81 is made of metal and has an inner diameter of 10 to 70 mm. Although it does not specifically limit as a metal which comprises the metal core 81, For example, metals, such as iron, aluminum, copper, or these alloys can be mentioned.

  The thickness of the cored bar 81 is 0.1 to 15 mm, and is determined in consideration of a balance between a request for energy saving (thinning) and strength (depending on the constituent materials). For example, in order to maintain the same strength as that of a cored bar made of iron of 0.57 mm with a cored bar made of aluminum, the wall thickness needs to be 0.8 mm.

  Examples of the fluororesin constituting the surface of the coating layer 82 include PTFE (polytetrafluoroethylene) and PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer).

  The thickness of the coating layer 82 made of a fluororesin is 10 to 500 μm, preferably 20 to 400 μm.

  When the thickness of the coating layer 82 made of the fluororesin is less than 10 μm, the function as the coating layer cannot be sufficiently exhibited, and the durability as the fixing device cannot be ensured. On the other hand, there is a problem that the surface of the coating layer exceeding 500 μm is easily scratched by paper dust, and toner or the like adheres to the scratched part, thereby causing image smearing.

  Further, as the elastic body constituting the covering layer 82, it is preferable to use silicon rubber, silicon sponge rubber or the like having good heat resistance such as LTV, RTV, HTV.

  The Asker C hardness of the elastic body constituting the covering layer 82 is less than 80 °, preferably less than 60 °.

  Moreover, 0.1-30 mm is preferable and, as for the thickness of the coating layer 82 which consists of an elastic body, 0.1-20 mm is more preferable.

  As the heating member 75, a halogen heater can be preferably used.

  The pressure roller 72 is formed by forming a coating layer 84 made of an elastic body on the surface of the cored bar 83. The elastic body constituting the coating layer 84 is not particularly limited, and examples thereof include various soft rubbers such as urethane rubber and silicone rubber, and sponge rubber. The silicon rubber exemplified as the one constituting the coating layer 84 and It is preferable to use silicon sponge rubber.

  Moreover, 0.1-30 mm is preferable and, as for the thickness of the coating layer 84, 0.1-20 mm is more preferable.

  The fixing temperature (surface temperature of the heating roller 10) is preferably 70 to 210 ° C., and the fixing linear velocity is preferably 80 to 640 mm / sec. The nip width of the heating roller is set to 8 to 40 mm, preferably 11 to 30 mm.

  The heating roller may be used by applying 0.3 mg or less of silicon oil per print, but may be used without oil.

  FIG. 3 is a schematic view showing an example of a fixing device (a type using a belt and a heating roller) used in the present invention.

  The fixing device 10 in FIG. 3 is a type using a belt and a heating roller in order to ensure a nip width, and the pressure pressed against the heating roller 601 through the heating roller 601 and the seamless belt 11 and the seamless belt 11. The pad (pressure member) 12a, the pressure pad (pressure member) 12b, and the lubricant supply member 40 constitute a main part.

  The heating roller 601 is formed by forming a heat-resistant elastic body layer 10b and a release layer (heat-resistant resin layer) 10c around a metal core (cylindrical core) 10a. A halogen lamp 14 is disposed as a heating source. The temperature of the surface of the heating roller 601 is measured by the temperature sensor 15, and the halogen lamp 14 is feedback-controlled by a temperature controller (not shown) based on the measurement signal, so that the surface of the heating roller 601 is adjusted to a constant temperature. The seamless belt 11 is in contact with the heating roller 601 so as to be wound at a predetermined angle, thereby forming a nip portion.

  Inside the seamless belt 11, a pressure pad 12 having a low friction layer on the surface is arranged in a state of being pressed against the heating roller 601 through the seamless belt 11. The pressure pad 12 is provided with a pressure pad 12a to which a strong nip pressure is applied and a pressure pad 12b to which a weak nip pressure is applied, and is held by a holder 12c made of metal or the like.

  Further, a belt traveling guide is attached to the holder 12c so that the seamless belt 11 smoothly slides and rotates. The belt running guide is preferably a member having a low coefficient of friction because it rubs against the inner surface of the seamless belt 11, and a member having low thermal conductivity is preferred so that heat is not easily taken from the seamless belt 11.

  FIG. 4 is a schematic view showing an example of a fixing device (a type using a soft roller and a heating roller) used in the present invention.

  A fixing device 10 shown in FIG. 4 is a type using a soft roller and a heating roller that secures a fixing nip and prevents winding of a transfer material and has excellent image quality, and includes a heating roller 601 as a heating roller member, A soft roller 17 b as a roller member is used, and a halogen lamp 14 as a heating member is provided inside the heating roller 601.

  A nip portion N is formed between the heating roller 601 and the soft roller 17b, and the toner image on the transfer material P is fixed by applying heat and pressure through the nip portion N. In the above description, a halogen lamp 14 (not shown) as a heating member may be disposed inside the soft roller 17b.

  Hereinafter, the present invention will be described in detail by way of representative embodiments, but the present invention is not limited to the following embodiments.

[Synthesis of binder resin fine particles]
201.5 g of styrene, 117.24 g of n-butyl acrylate, 18.31 g of methacrylic acid, 146.33 g of behenyl citrate, and 25.87 g of oleic amide were dissolved by heating, and an anionic surfactant (Emar E27C; manufactured by Kao Corporation; 27% active ingredient) 11.3 g was dissolved in 1107.05 g of pure water, added to a temperature maintained at 80 ° C., and stirred at high speed using CLEARMIX (MTechnic Co., Ltd.). Prepared.

  A stainless steel 5L (liter) four-headed reactor is equipped with a stirrer, cooling tube, nitrogen inlet tube, and temperature sensor, and 1005.59g of pure water, latex (monomer composition; methyl acrylate / butyl acrylate / itaconic acid) in the reactor = 78.5 / 16.5 / 5 (mass ratio), solid content 30%, average particle size 130 nm, Mw = 15,000) was added, and the internal temperature was raised to 80 ° C. The mixture was stirred while flowing nitrogen, and the monomer emulsion was added.

  Stirring while maintaining the internal temperature, an aqueous polymerization initiator solution in which 11.41 g of potassium persulfate was dissolved in 216.72 g of pure water was added, and the n-octyl mercaptan was added 7 times every 5 minutes to 5.23 g. It was dripped. Thereafter, polymerization was carried out at the same temperature for 30 minutes. Next, a polymerization initiator aqueous solution in which 9.96 g of potassium persulfate was dissolved in 186.25 g of pure water was added, and a mixture of 366.14 g of styrene, 179.12 g of n-butyl acrylate, and 8.63 g of n-octyl mercaptan was added over 1 hour. It was dripped. Furthermore, it superposed | polymerized for 1 hour and the binder resin fine particle (1) was obtained.

The average particle size (D ₅₀ ) was 195 nm, and the weight average molecular weight (Mw) was 18,000.

  Further, the binder resin fine particles (2) to (14) and the comparative binder resin fine particles (1) to (2) were prepared in the same manner as in the synthesis of the binder resin fine particles (1) except for the changes shown in Table 1 below. )

[Synthesis of resin fine particles for shell]
In a 5 L stainless steel reactor equipped with a stirrer, a cooling pipe, a nitrogen introducing pipe, and a temperature sensor, 2948 g of pure water and 2.3 g of an anionic surfactant (Emar 2FG manufactured by Kao Corporation) were dissolved, and the temperature was 80 ° C. under a nitrogen stream. The polymerization initiator aqueous solution dissolved in 10.2 g of pure potassium persulfate 218 g was added with stirring. Further, a monomer solution in which 520 g of styrene, 184 g of n-butyl acrylate, 96 g of methacrylic acid, and 22.1 g of n-octyl mercaptan were added dropwise over 3 hours, and then held at the same temperature for 1 hour to complete the polymerization. Was cooled to room temperature to obtain resin particles for shells. The average particle size was 82 nm, and the weight average molecular weight (Mw) was 13,200.

(Preparation of cyan colorant dispersion)
Cyan pigment C.I. I. After gradually adding 25 g of Pigment Blue 15: 3 (copper phthalocyanine pigment) to a surfactant aqueous solution in which 11.5 g of sodium n-dodecyl sulfate was dissolved in 160 g of pure water, Claremix W Motion CLM-0.8 (M Technique) And a cyan pigment dispersion having a volume average particle size of 138 nm was obtained.

[Synthesis of Toner (1) of the Present Invention]
Into a 5 L stainless steel reactor equipped with a stirrer, a cooling tube, and a temperature sensor, 146.142 g of binder resin fine particles (1) of the present invention, 1671.4 g of pure water, and 147.31 g of a cyan colorant dispersion were added and stirred. The pH was adjusted to 10 using 5 (mol / L) aqueous sodium hydroxide solution. Next, an aqueous magnesium chloride solution in which 56.66 g of magnesium chloride hexahydrate was dissolved in 56.66 g of pure water was added dropwise over 10 minutes with stirring, the internal temperature was raised to 75 ° C., and Coulter Counter TA-II (Beckman The particle size was measured using Coulter Co.). The mixture was heated and stirred until the average particle size reached 6.5 μm, and when the average particle size reached 6.5 μm, 244.18 g of the latex for shell was adjusted to pH = 4 with 5 (mol / L) sodium hydroxide aqueous solution. The adjusted shell latex was dropped, and heating and stirring were continued until the shell latex particles adhered to the surface of the aggregated particles. A small amount of the reaction solution was centrifuged using a centrifuge, and when the supernatant became transparent, a sodium chloride aqueous solution in which 73 g of sodium chloride was dissolved in 291.98 g of pure water was added. Furthermore, heating and stirring were continued, and the internal temperature was cooled to room temperature when the average circularity reached 0.965 using a flow type particle image measuring device FPIA2000 (manufactured by Sysmex Corporation). The produced particles were washed with pure water and filtered repeatedly, and then dried with hot air at 30 ° C. to obtain toner 1 of the present invention.

  The volume average particle diameter was 6.51 μm and the average circularity was 0.966.

[Synthesis of Toners (2) to (14) and Comparative Toners (1) to (2) of the Present Invention
The binder resin fine particles (1) of the present invention in the toner (1) of the present invention are changed to the binder resin fine particles (2) to (14) of the present invention and the comparative binder resin fine particles (1) to (2). Were carried out in the same manner to obtain toners (2) to (12) and comparative toners (1) to (2) of the present invention. The results are shown in Table 2 below.

[Toner particle external additive treatment]
In each of the toners (1) to (14) and the comparative toners (1) to (2) of the present invention, 1% by mass of hydrophobic silica (number average primary particle size 12 nm, degree of hydrophobicity = 68) and hydrophobicity 1% by mass of titanium oxide (number average primary diameter = 20 nm, degree of hydrophobicity = 64) is added and mixed with a Henschel mixer (Mitsui Miike Koki Co., Ltd.), and then coarse particles are removed using a 45 μm mesh sieve. Then, the ferrite particles are mixed with a carrier having an average particle diameter of 35 μm coated with styrene-acrylic resin and the toner concentration is 8%, and the developers (1) to (14) and the comparative developers (1) to (1) of the present invention are mixed. 2) was produced.

[Evaluation of performance]
(Offset property)
The fixing device of the commercial digital copying machine bizhub C6500 (manufactured by Konica Minolta Co., Ltd.) was modified to change the surface temperature of the fixing heat roller in the range of 100 to 210 ° C., and a solid band perpendicular to the conveying direction at each surface temperature. After transporting and fixing an A4 image with an image by vertical feeding, a solid band image of 5 mm width and a halftone image of 20 mm width were transported by vertical feeding perpendicularly to the transport direction, and image contamination due to fixing offset occurred. The temperature was measured on both the high temperature side and the low temperature side. The results are shown in Table 3.

(Fixability)
Using the developer and the bizhub C6500 remodeling machine, the toner was developed with a toner adhesion amount of 11 mg / cm ² , and then the transferred paper was heated at a temperature of the fixing heat roller in the range of 10 ° C./10% RH in increments of 5 ° C. Fixing was performed by changing the temperature to 210 ° C. Thereafter, the fixed image was folded using a folding machine, and 0.35 MPa of air was blown onto the fixed image, and the crease was evaluated in five stages with reference to a limit sample. The fixing temperature of rank 3 was set as the lower limit fixing temperature. .

  Rank 5: No peeling at all folds, Rank 4: Peeling according to some folds, Rank 3: Thin line peeling according to the folds, Rank 2: Thick peeling along the folds, Rank 1: Large peeling on the image.

  The results are shown in Table 3.

(Heat resistant storage)
Take 0.5 g of toner in a 10 ml glass bottle with an inner diameter of 21 mm, close the lid, shake 600 times with Tap Densor KYT-2000 (manufactured by Seishin Enterprise), remove the lid, and keep it in an environment of 57 ° C. and 35% RH for 2 hours. I left it alone. Next, place the toner on a 48 mesh (350 μm aperture) sieve, taking care not to crush it, set it on a powder tester (manufactured by Hosokawa Micron), fix it with a press bar and knob nut, and adjust the vibration strength to 1 mm. After adjusting and applying vibration for 10 seconds, the ratio of the amount of toner remaining on the sieve (toner aggregation rate (mass percent)) was measured.

The toner aggregation rate is a value calculated by the following formula.
(Toner aggregation rate (mass%)) = (residual toner mass (g) on sieve) /0.5 (g) × 100
The heat resistant storage stability of the toner was evaluated according to the following criteria.
A: The toner aggregation rate is less than 15% by mass (the toner has excellent heat-resistant storage stability)
○: toner aggregation rate is 20% by mass or less, 15% by mass or more (good heat storage stability of toner)
X: Toner aggregation rate exceeds 20% by mass (toner has poor heat-resistant storage property and cannot be used)
The results are shown in Table 3.

(Tacking resistance)
Evaluation of tacking was carried out by fixing two unfixed images prepared using a modified machine of bizhub C6500 (manufactured by Konica Minolta) with the developer of the present invention and the comparative developer at 150 ° C. with an external fixing device. The image area, the non-image area, and the image area are overlapped face-to-face, and a weight is placed on the overlapped portion so that the weight is equivalent to 80 g / cm ^2. The temperature is kept at 60 ° C. and 50% RH for 3 days. I left it alone. After being allowed to stand, image defects of the two fixed images superimposed were evaluated according to the following criteria. The results are shown in Table 4.

Excellent: No image defect due to toner transfer, no slight sticking between images, no problem at all Good: There is no zip noise when separating the superimposed images, but there is no problem Practical acceptable: Overlapped images When peeling, glossiness unevenness occurs in both images, but there is almost no defect as an image. Defect: Transfer to non-image area, peeling due to transfer between contact images is recognized, practical use is not possible. 4 shows.

  As is clear from Tables 3 and 4, when the developers (1) to (14) of the present invention are used, all the characteristics are good, but when the comparative developer is used, at least It can be seen that there is a problem with any of the characteristics.

1 is a cross-sectional configuration diagram illustrating an example of an image forming apparatus used in the present invention. Sectional drawing which shows an example of the fixing device (type using a pressure roller and a heating roller) used by this invention. FIG. 3 is a schematic diagram illustrating an example of a fixing device (a type using a belt and a heating roller) used in the present invention. Schematic which shows an example of the fixing apparatus (type using a soft roller and a heating roller) used by this invention.

Explanation of symbols

1Y, 1M, 1C, 1K Photoconductor 4Y, 4M, 4C, 4K Developing means 5Y, 5M, 5C, 5K Primary transfer means 6Y, 6M, 6M, 1K Blade cleaning means 7 Intermediate transfer member P Recording member (transfer material)

Claims (5)

In an electrostatic charge image developing toner containing at least a binder resin, a colorant and a release agent, the release agent contains an ester wax having an acid value and at least one fatty acid amide represented by the following general formula (1). A toner for developing an electrostatic charge image.
General formula (1) R ₁ CONHR ₂
(In the formula, R ₁ is selected from an alkyl group or alkenyl group having 12 to 50 carbon atoms, and R ₂ is selected from a hydrogen atom, an alkyl group having 12 to 50 carbon atoms, or an alkenyl group.) 2. The electrostatic image developing toner according to claim 1, wherein the fatty acid amide in the release agent is 1 to 20% by mass of the total toner mass. 2. The electrostatic image developing toner according to claim 1, wherein the ester wax having an acid value in the release agent comprises a compound having at least one carboxyl group and a long-chain alkyl alcohol. 4. The electrostatic charge image developing toner according to claim 3, wherein the releasing agent contains a partially esterified product and has an acid value of 3 to 20 mgKOH / g. 5. An image forming method, wherein the toner for developing an electrostatic charge image according to claim 1 is used for contact heating and fixing.

Images