JP2009271232A - Toner for electrostatic charge image development and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress solid uneven glossiness even in low temperature fixing, and to prevent transfer hollow defects. <P>SOLUTION: In the toner for electrostatic charge image development made by salting out and fusing at least a binder resin, a releasing agent, and a colorant, the toner includes a 12-30C straight chain alkyl alcohol or branched alkyl alcohol. The straight chain alkyl alcohol is mixed with the releasing agent, wherein the hydroxyl value is in a range of 5 to 25 mgKOH/g. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electrostatic image developing toner and an image forming method.

  In recent years, photographic images have been digitized, and there has been a demand for high-gloss images such as silver salt photographs in electrophotographic systems.

  In order to obtain a high-gloss image by the conventional method, it is necessary to form a release agent layer uniformly on the toner image, which tends to cause an increase in fixing temperature, a reduction in fixing speed, and a failure in transfer failure. First, technical means such as further forming a transparent toner layer on the toner image is employed.

  On the other hand, in order to reduce power consumption and high-speed printing, the energy of fixing devices has been reduced (low-temperature fixing) in recent years. However, reducing the energy with high-gloss technical means described above causes problems such as uneven gloss. It was difficult to achieve both high gloss and low energy.

  In addition, when attempting low-temperature fixing, it is necessary to keep the softening point and glass transition temperature of the binder resin low, so that on the developing roller during continuous printing, a blade, a toner transport roller, or a fixing device that regulates the toner layer This causes toner fusing to the heating roller and the like, causing image defects.

In order to solve this problem, attempts have been made to improve the image quality by incorporating silicon oil having a low surface tension into the toner (see, for example, Patent Document 1). However, the effect sufficient for practical use has not been improved.
JP 2004-295074 A

  The present invention has been made to solve the above problems.

  That is, an object of the present invention is to suppress solid gloss unevenness even in low-temperature fixing, and to improve transfer dropout.

  It has been found that the object of the present invention is achieved by adopting the following configuration.

(1)
A toner for developing an electrostatic charge image obtained by salting out and fusing at least a binder resin, a release agent, and a colorant, characterized by containing a linear alkyl alcohol having 12 to 30 carbon atoms or a branched alkyl alcohol. Toner for developing electrostatic images.

(2)
The toner for developing an electrostatic charge image according to (1), wherein the linear alkyl alcohol is mixed with a release agent to have a hydroxyl value in the range of 5 to 25 mgKOH / g.

(3)
The electrostatic charge image developing toner according to (1) or (2), wherein the releasing agent is an ester wax.

(4)
The electrostatic charge image developing toner according to (1), (2) or (3), wherein the toner is an emulsion polymerization / association toner obtained by salting out and fusing at least emulsion polymerization fine particles and colorant particles.

(5)
An image forming method comprising developing an electrostatic image formed on an electrophotographic photosensitive member using the electrostatic image developing toner according to any one of (1) to (4).

  By adopting the configuration of the present invention, it is possible to suppress solid gloss unevenness even in low-temperature fixing and to improve transfer dropout.

  The present invention will be further described.

  The constitution of the present invention is primarily to contain a long-chain alkyl alcohol in an electrostatic image developing toner obtained by agglomerating at least a binder resin, a release agent and a colorant and heat-fusing. It is.

  Hereinafter, each requirement constituting the present invention will be described.

[Long chain alkyl alcohol]
The effect of the present invention is achieved by including a long-chain alkyl alcohol (higher alcohol) in the toner. Examples of long-chain alkyl alcohols include linear alkyl alcohols having 12 to 30 carbon atoms and branched alkyl alcohols.

  Moreover, higher fatty acid partial esterified products of polyhydric alcohols can also be used. Examples of the polyhydric alcohol include glycols such as ethylene glycol and propylene glycol, glycerin monomers and multimers such as glycerin, diglycerin, triglycerin, and polyglycerin, pentaerythritol, sorbitan, and cholesterol. These polyhydric alcohols obtained by partial esterification with higher fatty acids having 12 to 30 carbon atoms can be used. These long-chain alkyl alcohols are selected based on the melting point and the melt viscosity. The melting point is preferably 30 ° C. or higher, and the melt viscosity is preferably 2 mPa · s or higher at 100 ° C.

  The long-chain alkyl alcohol of the present invention can be mixed with a release agent or used separately. For example, after mixing with a mold release agent and melting, it can be dispersed in an aqueous surfactant solution and used as fine particles.

  Moreover, it can disperse | distribute to surfactant aqueous solution separately from a mold release agent, and can be used as a long-chain alkyl alcohol fine particle dispersion. Furthermore, it is also possible to use fine particles obtained by seed polymerization using the release agent and long-chain alkyl alcohol fine particles as core particles. Among them, as a preferable method, it is preferable to use fine particles obtained by so-called miniemulsion polymerization in which a release agent and a long-chain alkyl alcohol are dissolved in a monomer solution, and this is finely dispersed in an aqueous surfactant solution and polymerization is performed. .

  The addition amount of the long-chain alkyl alcohol of the present invention is preferably added so as to be in the range of 5 to 25 mg KOH / g in terms of hydroxyl value (OHV) when mixed with the release agent.

  The hydroxyl value is the number of mg of sodium hydroxide corresponding to the hydroxyl group in 1 g of the raw material, and hydroxylation required to neutralize acetic acid required for acetylation by acetylating the hydroxyl group (—OH) in the sample. The amount of potassium is expressed in terms of mg with respect to 1 g of the sample, and is a scale indicating the hydroxyl group content in the sample. Various reagents are used for acetylation. Usually, a mixture of pyridine and acetic anhydride is used, and the measurement is performed by titrating the difference in acid concentration before and after acetylation.

  The addition amount of the long-chain alkyl alcohol of the present invention is preferably added so as to be in the range of 5 to 25 mg KOH / g in terms of hydroxyl value (OHV) when mixed with the release agent. When the amount is less than 5 mgKOH / g, the effect of suppressing solid gloss unevenness is small.

〔Release agent〕
Examples of the release agent include low molecular weight polyolefins such as polyethylene, polypropylene and polybutene, silicones having a softening point by heating, fatty acid amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide and stearic acid amide, carna Examples include vegetable waxes such as uba wax and rice wax, animal waxes such as beeswax, montan wax, ceresin, paraffin wax, and Fischer-Tropsch wax. Preferably, esters of long-chain alkyl monoalcohols having 12 to 30 carbon atoms such as stearyl stearate, palmityl palmitate and behenyl behenate and higher fatty acids having 12 to 30 carbon atoms, dibehenyl itaconate, distearyl maleate Esters of polycarboxylic acids such as tristearyl aconite and long-chain alkyl alcohols having 12 to 30 carbon atoms, such as tristearic acid glyceride, tribehenic acid glyceride, pentaerythritol tetrabehenate, pentaerythritol tetrastearate, etc. Esters consisting of polyhydric alcohols and higher fatty acids having 12 to 30 carbon atoms, tetrastearic acid diglyceride, tetrabehenic acid diglyceride, hexabehenic acid triglyceride, decastearic acid, glycerides, dipentaerythritol Higher fatty acids having 12 to 30 carbon atoms such as hexastearate and polyhydric alcohol multimers, sorbitan tristearate, sorbitan tribenate, sorbitan higher fatty acid esters such as sorbitan trioleate, cholesteryl stearate, cholesteryl Examples include cholesterol fatty acid esters such as behenate and cholesteryl oleate. These are selected depending on the melting point, melt viscosity, etc., and may be used alone or in combination of two or more.

  These release agents preferably have a melting point of 30 ° C. or higher and a melt viscosity of 100 ° C. and 2 mPa · s or higher. The release agent in the present invention is preferably contained in the toner in an amount of 0.5 to 50% by mass, more preferably 1 to 40% by mass.

  In particular, it is more preferable to add 1 to 15% by mass of a release agent having a melting point of 50 to 100 ° C., since the offset property is improved when the fixing temperature is low and the gloss unevenness is increased.

  The release agent melting point of the toner can be measured using “DSC-7 differential scanning calorimeter” (manufactured by PerkinElmer) or “TAC7 / DX thermal analyzer controller” (manufactured by PerkinElmer).

  As a measurement procedure, 4.5 to 5.0 mg of toner is precisely weighed to two digits after the decimal point, sealed in an aluminum pan (KIT No. 0219-0041), and set in a DSC-7 sample holder. The reference used an empty aluminum pan. The measurement conditions were a measurement temperature of 0 ° C. to 200 ° C., a temperature increase rate of 10 ° C./min, a temperature decrease rate of 10 ° C./min, and heat-cool-heat temperature control. Analysis was performed based on the data in Heat, and the peak top temperature of the release agent endothermic peak was defined as the release agent melting point.

[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. The core particles preferably contain the release agent and a long-chain alkyl alcohol.

  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 between the core particles and the shell (which may be a single layer or multiple layers) of the toner of the present invention is preferably 10 to 30% by mass with respect to the mass of the core particles.

  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 dispersion of resin fine particles (3) Agglomeration of resin fine particles and colorant particles in an aqueous medium, Aggregation and fusion step for fusing to obtain core particles (associate particles) (4) First ripening step for adjusting the shape by aging associated particles with thermal energy (5) In dispersion of core particles (associate particles) Shell forming step of adding core resin particles and aggregating and fusing the shell particles on the surface of the core particles to form core / shell structure toner particles (6) Heating the core / shell structure toner particles to heat Second aging step for adjusting the shape of toner particles having a core / shell structure by aging with energy (7) Solid-liquid separation of the toner particles from the cooled toner particle dispersion, and a surfactant or the like from the toner particles To remove Step (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.

  The above process will be described in detail below.

  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 core particles constituting the toner of the present invention are produced by a production method in which resin fine particles and colorant particles are aggregated and fused. The shape of the core particles 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.

  For example, the core particles constituting the toner of the present invention are obtained by dissolving or dispersing a release agent component in a polymerizable monomer forming the resin (A), and then mechanically dispersing fine particles in an aqueous medium. A method of salting out and fusing the composite resin fine particles and the colorant particles formed through the step of polymerizing a polymerizable monomer by an emulsion polymerization method 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 (A) 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. It is preferable to add a long-chain alkyl alcohol during this step.

[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 advance 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, a long-chain alkyl alcohol 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 the case of using uncolored resin fine particles, a dispersion of colorant fine particles is added to the dispersion of resin fine particles in the agglomeration / 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. In the agglomeration / fusion step, internal additive fine particles such as release agent fine particles and charge control agents can be agglomerated and fused together with resin fine particles and colorant fine 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 fine 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 fine 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 there is a problem that particle size control is difficult, 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.

  And in this invention, it controls so that the formed core particle may become what has an uneven | corrugated shape by controlling the heating temperature of the aggregation / fusion process, and the heating temperature and time of the 1st ripening process. Specifically, the heating temperature is lowered in the agglomeration / fusion process to suppress the progress of fusion between the resin particles to promote deforming, the heating temperature is lowered in the first aging process, and Shorten the time to control the core particles to be uneven.

[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.

  In the present invention, it is possible to produce a rounded toner having a uniform shape through the above-described steps. Further, it is possible to control the shape of the toner particles in the true sphere direction by setting the time of the second aging step longer or by setting the aging temperature higher.

[Cooling process]
This process is a process of cooling the toner particle dispersion (rapid cooling process). 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 mixing the dried toner particles with an external additive as necessary to produce a toner.

  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, a non-magnetic one-component developer or a magnetic one-component developer containing about 0.1 to 0.5 μm of magnetic particles in the toner can be used. 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 preferred. 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 on the upper part of 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 from the endless belt-shaped intermediate transfer body 70 from which the recording member P is separated by the curvature by the cleaning means 6A.

  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-described 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 a transfer material (transfer paper) 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 a 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.

  In addition, 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, and 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 and sponge rubbers such as urethane rubber and silicone 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.

  4 is a type using a soft roller and a heating roller that secures a fixing nip and prevents the transfer material from being wound and has excellent image quality. The 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.

Examples of the present invention will be described below, but the present invention is not limited to these examples. In the following, “part” means “part by mass”.
[Preparation Example 1 of Colorant Fine Particle Dispersion]
Stirring and dissolving 11.5 parts by mass of sodium n-dodecyl sulfate in 160 parts by mass of ion-exchanged water; I. Pigment Blue 15: 3; 25 parts by mass are gradually added, and then dispersed using “Clearmix W Motion CLM-0.8” (manufactured by M Technique Co., Ltd.), and the volume-based median diameter is 158 nm. Colorant fine particle dispersion [1] containing colorant fine particles [1] was obtained.

The volume-based median diameter was measured under the following measurement conditions using “MICROTRAC UPA 150” (manufactured by Nikkiso Co., Ltd.).
(Measurement condition)
Sample refractive index: 1.59
Sample specific gravity: 1.05 (in terms of spherical particles)
Solvent refractive index: 1.33
Solvent Viscosity: a at ^{30 ℃ 0.797 × 10 -3 Pa /} s, 1.002 at ^{20 ℃ × 10 -3 Pa / s} .

In addition, ion-exchange water was put into the measurement cell and zero point adjustment was performed.
[Preparation Example 2 of Colorant Fine Particle Dispersion]
C. in the preparation example of the colorant fine particle dispersion. I. Pigment Blue 15: 3 to C.I. I. A colorant fine particle dispersion was prepared in the same manner except that it was changed to Pigment Red 122 to obtain a colorant fine particle dispersion [2] containing colorant fine particles [2] having a volume-based median diameter of 183 nm.
[Preparation Example 3 of Colorant Fine Particle Dispersion]
C. in the preparation example of the colorant fine particle dispersion. I. Pigment Blue 15: 3 to C.I. I. A colorant fine particle dispersion was prepared in the same manner except that it was changed to Pigment Yellow 74 to obtain a colorant fine particle dispersion [3] containing colorant fine particles [3] having a volume-based median diameter of 176 nm.
[Preparation Example 4 of Colorant Fine Particle Dispersion]
C. in the preparation example of the colorant fine particle dispersion. I. Colorant fine particle dispersion [4] containing colorant fine particles [4] having a volume-based median diameter of 171 nm was prepared in the same manner except that Pigment Blue 15: 3 was changed to Mogul L. Got.
[Preparation Example 1 of Core Forming Resin Particles]
1) First stage polymerization:
Surfactant solution in which 4 parts by mass of an anionic surfactant represented by the following formula 1 is dissolved in 3040 parts by mass of ion-exchanged water in a 5 L reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introducing device. The internal temperature was raised to 80 ° C. while stirring at a stirring speed of 230 rpm under a nitrogen stream.

An initiator solution in which 10 parts by mass of a polymerization initiator (potassium persulfate; KPS) was dissolved in 400 parts by mass of ion-exchanged water was added to this surfactant (formula 1 below) solution, and the temperature was 75 ° C. Thereafter, a monomer mixed solution consisting of 532 parts by mass of styrene, 200 parts by mass of n-butyl acrylate, 68 parts by mass of methacrylic acid, and 16.4 parts by mass of n-octyl mercaptan was added dropwise over 1 hour. Polymerization (first stage polymerization) was carried out by heating and stirring for 2 hours to prepare latex [A1] which is a dispersion of core particles. The weight average molecular weight (Mw) of the core particles in this latex [A1] was 16,500.
Formula _{1: C 10 H 21 (OCH} 2 CH 2) 2 SO 3 Na
2) Second stage polymerization:
In a flask equipped with a stirrer, 233 parts by mass of styrene, 123.7 parts by mass of n-butyl acrylate, 24.5 parts by mass of methacrylic acid, 3.48 parts by mass of n-octyl mercaptan, A monomer solution was prepared by adding 85.6 parts by mass of a mold release agent represented by the following compound 1 and 8.2 parts by mass of behenyl alcohol and heating to 80 ° C. to dissolve.

Compound 1: Pentaerythritol tetrabehenate On the other hand, a surfactant solution in which 3 parts by mass of the anionic surfactant represented by the above formula 1 was dissolved in 1560 parts by mass of ion-exchanged water was heated to 80 ° C., After adding 32.8 parts by mass of the above-mentioned latex [A1] to the surfactant solution in terms of solid content, the mold release is performed by a mechanical disperser “CLEAMIX” (manufactured by M Technique Co., Ltd.) having a circulation path. The monomer solution of the agent was mixed and dispersed for 30 minutes to prepare a dispersion (emulsion).

Next, an initiator solution prepared by dissolving 11.9 parts by weight of a polymerization initiator (KPS) in 290 parts by weight of ion-exchanged water is added to the dispersion, and the system is heated and stirred at 80 ° C. for 3 hours. Thus, polymerization (second stage polymerization) was performed to prepare latex [A2].
3) Third stage polymerization:
An initiator solution in which 3.19 parts by mass of a polymerization initiator (KPS) is dissolved in 130 parts by mass of ion-exchanged water is added to the resin particles [A2] obtained as described above, and a temperature condition of 80 ° C. is added. A monomer mixed solution consisting of 173 parts by mass of styrene, 83.4 parts by mass of n-butyl acrylate, and 4.16 parts by mass of n-octyl mercaptan was lowered over 1 hour. After completion of the dropwise addition, polymerization (third stage polymerization) is performed by heating and stirring for 2 hours, followed by cooling to 28 ° C. and dispersion of the core-forming resin particles [A] composed of composite resin particles having a multilayer structure A liquid latex [A3] was obtained.
[Preparation Example 2 of Core Forming Resin Particles]
A latex [B3], which is a dispersion of the core-forming resin particles [B], was obtained in the same manner except that the release agent in Preparation Example 1 of the core-forming resin particles was changed to the following compound 2.

Compound 2: Glycerin tribehenate [Preparation Example 3 of resin particles for core formation]
A latex [C3], which is a dispersion of the core-forming resin particles [C], was obtained in the same manner except that the release agent in Preparation Example 1 of the core-forming resin particles was changed to Compound 3.
_{CH 3 (CH 2) 20 COO} (CH 2) 20 CH 3
Compound 3: behenyl behenate [Preparation Example 4 for Core-Forming Resin Particles]
Latex which is a dispersion of core-forming resin particles [D], except that the release agent in Preparation Example 1 of core-forming resin particles is changed to paraffin wax “HNP-12” (manufactured by Nippon Seiwa Co., Ltd.). D3] was obtained.
[Preparation Example 5 of Core Forming Resin Particles]
1. 85.6 parts by mass of a release agent represented by Compound 1 of Preparation Example 1 for core-forming resin particles and 91.1 parts by mass of a release agent represented by Compound 1 and 8.2 parts by mass of behenyl alcohol A latex [E3], which is a dispersion of the core-forming resin particles [E], was obtained in the same manner except that the amount was changed to 7 parts by mass.
[Preparation Example 6 of Core Forming Resin Particles]
12. 85.6 parts by weight of a release agent represented by Compound 1 of Preparation Example 1 of resin particles for core formation and 8.2 parts by weight of a release agent represented by Compound 1 of 80.2 parts by weight and behenyl alcohol A latex [F3], which is a dispersion of the core-forming resin particles [F], was obtained in the same manner except that the amount was changed to 6 parts by mass.
[Preparation Example 7 for Core-Forming Resin Particles]
85.6 parts by mass of the mold release agent represented by Compound 1 in Preparation Example 1 of core-forming resin particles and 8.2 parts by mass of the mold release agent represented by Compound 1 and 87 parts by mass of stearyl alcohol 6.8 A latex [G3], which is a dispersion of the core-forming resin particles [G], was obtained in the same manner except that the mass parts were changed.
[Preparation Example 8 of Core Forming Resin Particles]
85.6 parts by mass of the release agent represented by Compound 1 in Preparation Example 1 of core-forming resin particles, 8.2 parts by mass of behenyl alcohol, 90.4 parts by mass of the release agent represented by Compound 1, and pentaerythritol 3 The latex [H3], which is a dispersion of the core-forming resin particles [H], was obtained in the same manner except that the amount was changed to 4 parts by mass.
[Preparation Example 9 of Core Forming Resin Particles]
85.6 parts by mass of a mold release agent represented by Compound 1 in Preparation Example 1 of core-forming resin particles and 8.2 parts by mass of 92.7 parts by mass of a mold release agent represented by Compound 1 and behenyl alcohol A latex [I3], which is a dispersion of the core-forming resin particles [I], was obtained in the same manner except that the amount was changed to 1 part by mass.
[Preparation Example 10 of Core Forming Resin Particles]
17. 75.6 parts by weight of a release agent represented by Compound 1 and 87.4 parts by weight of behenyl alcohol represented by Compound 1 in Preparation Example 1 of core-forming resin particles 77.4 parts by weight and behenyl alcohol represented by Compound 1 A latex [J3], which is a dispersion of the core-forming resin particles [J], was obtained in the same manner except that the amount was changed to 4 parts by mass.
[Preparation Example 11 of Core Forming Resin Particles]
Except that 85.6 parts by weight of the release agent represented by Compound 1 in Preparation Example 1 of the core-forming resin particles and 8.2 parts by weight of behenyl alcohol were changed to 93.8 parts by weight of the release agent represented by Compound 1. Similarly, latex [K3], which is a dispersion of core-forming resin particles [K], was obtained.
[Preparation Example 12 for Core-Forming Resin Particles]
Latex that is a dispersion of core-forming resin particles [L], except that the release agent represented by Compound 1 in Preparation Example 11 of Core-Forming Resin Particles was changed to the release agent represented by Compound 2. [L3] was obtained.
[Preparation Example 13 of Core-Forming Resin Particles]
Latex that is a dispersion of core-forming resin particles [M], except that the release agent represented by Compound 1 in Preparation Example 11 of Core-Forming Resin Particles was changed to the release agent represented by Compound 3 [M3] was obtained.
[Preparation Example 14 for Core-Forming Resin Particles]
Preparation of core-forming resin particles The core-forming resin particles [N] were similarly prepared except that the release agent represented by Compound 1 in Preparation Example 11 was changed to paraffin wax “HNP-12” (manufactured by Nippon Seiwa Co., Ltd.). Latex [N3] as a dispersion was obtained.

[Example of preparation of resin particles for shell formation]
600 parts by mass of water was charged in a 1 L reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introduction device, and the internal temperature was raised to 70 ° C. while stirring at a stirring speed of 230 rpm under a nitrogen stream. 119 parts by mass of styrene, 33 parts by mass of n-butyl acrylate, 8 parts by mass of methacrylic acid and 4.5 parts by mass of n-octyl mercaptan were added thereto, and 3 parts by mass of a polymerization initiator (potassium persulfate; KPS) was ion-exchanged. An aqueous solution dissolved in 40 parts by mass of water was added, and the system was heated and stirred at 70 ° C. for 10 hours to prepare resin particles for shell formation.

The shell-forming resin particles had a weight average molecular weight (Mw) of 13,200. The number average particle diameter of the composite resin particles constituting the shell-forming resin particles was 221 nm, and the glass transition temperature (Tg) was 55.4 ° C.
[Toner Preparation Example 1]
1) Formation of core particles:
420 parts by mass of the latex of the above core-forming resin particles [A] in terms of solid content, 900 parts by mass of ion-exchanged water, and 200 parts by mass of the colorant fine particle dispersion [1], a temperature sensor, a cooling tube, The mixture was stirred in a reaction vessel equipped with a nitrogen introducing device and a stirring device. After adjusting the temperature in a container to 30 degreeC, 5 mol / L sodium hydroxide aqueous solution was added to this solution, and pH was adjusted to 8-11.

Next, an aqueous solution obtained by dissolving 2 parts by mass of magnesium chloride hexahydrate in 1000 parts by mass of ion-exchanged water was added over 10 minutes at 30 ° C. with stirring. After standing for 3 minutes, the temperature was raised and the system was heated to 65 ° C. over 60 minutes. In this state, the particle size of the associated particles was measured with “Coulter Counter TA-II” (manufactured by Beckman Coulter), and when the volume-based median diameter reached 6.5 μm, 40.2 parts by mass of sodium chloride An aqueous solution in which 1000 parts by mass of ion-exchanged water is dissolved is added to stop the growth of the particle size, and further, the fusion is continued by heating and stirring at a liquid temperature of 70 ° C. for 1 hour as an aging treatment, and the core particles [ 1] was formed. When the circularity of the core particle [1] was measured by “FPIA2000” (manufactured by Systex), the average value was 0.918.
2) Formation of shell layer:
Next, after adding 210 parts by mass of a latex of resin particles for shell formation at 65 ° C., an aqueous solution in which 2 parts by mass of magnesium chloride hexahydrate is dissolved in 1000 parts by mass of ion-exchanged water is added over 10 minutes. The temperature was raised to 70 ° C. (shelling temperature), and stirring was continued for 1 hour. After the resin particles for forming the shell were fused on the surface of the core particles, the aging treatment was performed at 75 ° C. for 20 minutes. Layers were formed. Here, 40.2 parts by mass of sodium chloride was added, the mixture was cooled to 30 ° C. at 6 ° C./min, the produced fused particles were filtered, washed repeatedly with ion-exchanged water at 45 ° C. The toner [1] having a shell layer formed on the surface of the core particles was produced by drying with warm air.
[Toner Preparation Examples 2 to 56]
Toners [2] to [56] were prepared in the same manner as in Toner Preparation Example 1 except that the colorant fine particle dispersion and the core-forming resin particles were changed as shown in Tables 2 and 3 below. .

[External process]
1% by mass of hydrophobic silica (number average primary particle size = 12 nm, degree of hydrophobicity = 68) and hydrophobic titanium oxide (number average primary particle size = 20 nm, degree of hydrophobicity) were prepared in the above “Toners 1 to 56”. = 63) was added in an amount of 1.2% by mass, mixed with a Henschel mixer, and then coarse particles were removed using a sieve having an opening of 45 μm to prepare “Toners 1 to 56”.

The volume-based median diameter was measured under the following measurement conditions using “MICROTRAC UPA 150” (manufactured by Nikkiso Co., Ltd.).
(Measurement condition)
Sample refractive index: 1.59
Sample specific gravity: 1.05 (in terms of spherical particles)
Solvent refractive index: 1.33
Solvent Viscosity: 30 ° C. at ^{0.797 × 10 -3 Pa · s,} 20 ℃ at 1.002 × ¹⁰ -3 Pa · s
In addition, ion-exchange water was put into the measurement cell and zero point adjustment was performed.

(Preparation of developer)
Next, a ferrite carrier having a volume average particle diameter of 35 μm coated with styrene acrylic resin was mixed with each of the prepared toners to prepare “Developers 1 to 56” having a toner concentration of 8% by mass.

[Live test 1-12]
Using the developer prepared as described above, a full-color image having a pixel rate of 30% was continuously formed by using a commercially available digital copying machine bizhub PRO C500 in a temperature of 20 ° C. and a relative humidity of 50% RH. The formed image of the 30,000th sheet is visually checked for the presence of an image defect (letter transfer missing, solid gloss unevenness), and a fixed image is printed with a Macbeth reflection densitometer “RD-918”. The absolute image density was measured by measuring the absolute image density at any 20 locations on the white background, and the average value and the absolute image density at any 20 locations on the transfer paper before being subjected to image formation processing were measured. The difference from the average value was determined as the fog density. The results are shown in the table.

A method for evaluating the transfer omission and solid gloss unevenness is as follows.
・ Transfer missing In the toner layer developed on the photoconductor, if the cohesive force between the toners is too strong at the transfer part, the toner is not transferred to the transfer body near the center of the image, especially in the fine line image part, It remains on the photoconductor and a defect occurs on the image.

<Evaluation of transfer dropout>
Using bizhub C350, copy 50 sheets of blank paper (printing rate 0%) on the side of A4, and then copy a grid image with a line width of 0.4 mm for each of Y, M, C, and K colors to check the image. .

◎ (excellent): no void occurred in the lattice image. ○ (good): Spot void in the lattice image could be confirmed with a 15X magnifier.

  Δ (possible): Streaks in the lattice image can be confirmed with a 15 × magnifier.

X (impossible): streaky voids can be visually confirmed in the lattice image.
・ Solid gloss unevenness When the toner on the image is cooled and the toner on the image is cooled, the speed of recrystallization of the wax in the toner varies, resulting in uneven gloss on the image. To do.

<Evaluation of solid gloss unevenness>
Using art paper (manufactured by Mitsubishi Paper Industries Co., Ltd., Tokishi Art) as a recording medium, the printed solid image was evaluated visually or with a loupe as follows, and ま た は or ○ was accepted.

A: Gloss unevenness cannot be detected at all. ○: Gloss unevenness cannot be detected at all unless magnified with a loupe. X: Striped gloss unevenness can be detected visually.

  Developers 1 to 40 in the present invention are all good in properties, but it is understood that developers 41 to 56 outside the present invention have problems in at least any of the properties.

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)

A toner for developing an electrostatic charge image obtained by salting out and fusing at least a binder resin, a release agent, and a colorant, characterized by containing a linear alkyl alcohol having 12 to 30 carbon atoms or a branched alkyl alcohol. Toner for developing electrostatic images. 2. The electrostatic image developing toner according to claim 1, wherein the linear alkyl alcohol is mixed with a release agent to have a hydroxyl value in the range of 5 to 25 mg KOH / g. The electrostatic charge image developing toner according to claim 1, wherein the releasing agent is an ester wax. 4. The electrostatic charge image developing toner according to claim 1, wherein the toner is an emulsion polymerization / association toner obtained by salting out and fusing at least emulsion polymerization fine particles and colorant particles. An image forming method comprising developing the electrostatic image formed on the electrophotographic photosensitive member using the electrostatic image developing toner according to claim 1.

Images