JP2006313232A - Electrostatic image developing toner and image forming method using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic image developing toner which has such good fixing performance that even if fixed at such a low fixing temperature that a surface temperature of a transfer material becomes about 100°C, a formed toner image does not peel from the transfer material, and which has such high durability that the toner is free from variation in the charge rising performance after continuous mass printing of several hundred thousand sheets. <P>SOLUTION: The electrostatic image developing toner contains a binder resin and a colorant, wherein the toner contains at least one compound represented by formula (1) wherein R<SB>1</SB>and R<SB>2</SB>each represent an alkyl group which may have a 10-30C substituent; X represents H or -CO-R<SB>4</SB>, and R<SB>4</SB>represents an alkyl group which may have a 1-4C substituent. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electrostatic image developing toner, and more particularly, to an electrostatic image developing toner containing an ester compound having a specific structure and an image forming method using the same.

  In the field of electrophotographic image forming technology such as copiers and printers, with the advancement of digital technology, a minute dot image of 1200 dpi (dpi represents the number of dots per 2.54 cm) level has recently been accurately obtained. The technology of the level that can be reproduced in the world has been required.

  In order to faithfully reproduce such a small dot image, the reduction of the toner particle diameter has been studied, and a chemical toner represented by a polymerized toner that can be subjected to various controls in the manufacturing process has attracted attention. Thus, it has become possible to obtain a small-diameter toner that faithfully reproduces a minute dot image (see, for example, Patent Document 1).

  On the other hand, as a method for fixing a toner image transferred onto an image forming support such as paper, a contact fixing method represented by a heat roll fixing method or a heat belt fixing method is widely used. However, the contact fixing method has a problem that an offset current state in which the molten toner adheres to the heating member and the toner attached to the heating member is transferred to the image forming support easily occurs.

  As a means for preventing the occurrence of an offset phenomenon, for example, there has conventionally been a method of applying silicone oil to the surface of a heating member of a fixing device to impart releasability to the heating member. However, it was impossible to write with a writing instrument such as a ballpoint pen, or it was inconvenient for use in office machines such as contamination by volatile components in silicone oil.

  Accordingly, development of an oilless toner in which releasability is imparted to the toner particles themselves has been studied, and a technique for adding a fixing improver that expresses releasability in the toner particles has appeared. As a compound exhibiting releasability, for example, an oilless chemical toner containing a compound such as an ester compound of a higher fatty acid containing a long-chain hydrocarbon group has been developed (for example, a patent document). 2 and 3). The advent of toners containing this ester compound as a release agent has greatly contributed to the development of oilless image forming technology.

  By the way, recently, in order to consider the environmental impact associated with image formation and to reduce business costs in the office, the power consumption of printers and copiers has been increased. As one of the countermeasures, a technique for fixing at a temperature lower than the current fixing temperature has attracted attention. In addition, because of the characteristic that a required number of sheets can be printed when necessary, an electrophotographic image forming apparatus has been newly used also in the field of light printing.

However, it has been confirmed that when the toner containing the ester compound described above is used for fixing at a low temperature, the formed toner image tends to be peeled off from the transfer material. In addition, when a large amount of continuous printing is performed such that printing is repeated at the level of hundreds of thousands of sheets, there is a tendency for the toner charge rising performance to deteriorate, and even if a large amount of image formation is repeated, the charge rising tendency changes. There was a demand for durability. As described above, it is necessary to provide the oilless toner with performance that sufficiently satisfies new trends and needs in the market.
JP 2000-214629 A (see paragraph 0061, etc.) JP 2002-287405 A (see paragraph 0051, etc.) JP2003-91101A (see paragraph 0208 etc.)

  The present invention has been made in view of the above problems. For example, a toner image does not peel from the transfer material even when the surface temperature of the transfer material is fixed at a low temperature of about 100 ° C. Another object of the present invention is to provide a toner for developing an electrostatic image capable of exhibiting good adhesiveness and an image forming method using the same.

  In addition, the present invention, for example, has a durable electrostatic charge image developing toner that does not change the charge rising performance of the toner even when a large number of hundreds of thousands of sheets are continuously printed, and the same. An object is to provide an image forming method.

  The inventors of the present invention have applied the toner containing the compound represented by the general formula (1) to an image forming apparatus compatible with so-called low-temperature fixing, for example, that fixes a transfer material at a surface temperature of about 100 ° C. It has been found that when used, the toner image does not peel off from the transfer material and exhibits a strong fixing performance.

  That is, the subject of this invention is achieved by taking the following structure.

(Claim 1)
An electrostatic charge image developing toner containing at least a binder resin and a colorant, wherein the electrostatic charge image developing toner contains at least one compound represented by the following general formula (1).

(Wherein, R ₁ and R ₂ represent an alkyl group which may have a substituent group having 10 to 30 carbon atoms, a X mother, H or -CO-R _4. In addition, R ₄ is the number of carbon atoms Represents an alkyl group which may have 1 to 4 substituents.)
(Claim 2)
An image forming method, comprising: transferring a toner image formed on an electrophotographic photosensitive member using the electrostatic image developing toner according to claim 1 to a transfer material;

  As a result of intensive studies by the inventor of the present invention, polyhydric carboxylic acids having a hydroxyl group as in the present invention, which are esters with a long-chain alcohol and having a hydroxyl group in the molecule, or the hydroxyl group is esterified. It has been found that those that have a certain effect.

  Conventionally, there are known higher fatty acid esters having a long-chain hydrocarbon group. However, those having long-chain fatty acids can exhibit a demolding effect because they have an ester group and a plurality of long-chain hydrocarbon groups in the molecule. This also hinders the fixing property of the toner to the body itself and has a problem that the fixing property itself deteriorates.

  Further, since these higher fatty acid esters have an ester group at the center as a structure, they are dispersed in the particles when applied to a so-called polymerization method toner, and cannot be present on the surface for giving a charge. As a result, the charging property is not affected. Furthermore, since it is easy to exist in this way, it was doubtful whether the mold release effect could be exhibited to the maximum extent.

  However, the ester having the structure of the present invention has two long-chain aliphatic hydrocarbon ester groups, and further has a short aliphatic hydrocarbon ester group or hydroxyl group in the molecule. It has been found that by adopting this structure, the release effect can be exhibited by the presence of the long-chain hydrocarbon group, and at the same time, the fixing property to the support can be improved.

  As described above, it is not clear why the toner image formed using the toner containing the ester compound having a specific structure has developed a strong fixing performance even if it is fixed at a low temperature. Is guessed.

  That is, the structure of the ester compound used in the present invention has two long-chain hydrocarbon ester groups and a short-carbon ester group or a hydroxyl group, and is excellently separated by the presence of the long-chain aliphatic hydrocarbon group. It is presumed that the mold effect was expressed. Further, due to the presence of the ester group of the long-chain aliphatic hydrocarbon group, a fine domain structure is formed to promote the release effect in order to disperse in the toner particles with a certain degree of affinity. Presumed to be.

  Also, due to the presence of ester groups and hydroxyl groups of short aliphatic hydrocarbons having 1 to 4 carbon atoms in the ester compound, these portions are blended with the cellulose component constituting the paper as the transfer material, to form a toner transfer material. It is thought that the adhesiveness of this was improved. The presence of this part itself acts in the direction of reducing the release effect, but due to the presence of a plurality of long-chain aliphatic hydrocarbon groups, these components with high affinity to the fixing roller are quickly oriented and released. It is presumed that the effect is prevented from decreasing. This effect was more noticeable with the toner having a reduced diameter.

  Further, in the present invention, it has been found that the charge rising performance of the toner does not fluctuate even when large-scale printing of several hundred thousand sheets is performed. This is because the compound represented by the general formula (1) is an ester. This is presumably due to the fact that a substituent having a high affinity for water, such as a group or a hydroxyl group, is arranged in the center of the compound. That is, the presence of an ester group near the quaternary carbon (a carbon atom not directly bonded to a hydrogen atom) in the compound makes it possible to form the quaternary carbon of the ester compound when toner particles are formed in water. It is presumed that the structure has a portion oriented on the water side. It is presumed that the charge rising effect is expressed by the action of the polar group dispersed on the toner particle surface, and the charge rising performance of the toner is improved.

  Regarding the improvement of the fixability, since the structure has a short aliphatic hydrocarbon ester group or hydroxyl group in the molecule, this portion is oriented to the cellulose component of the paper, and as a result, the adhesion between the paper and the toner Can be improved. The presence of this part itself is expected to affect the fixing roller (reduction of the mold release effect), but in reality there are multiple long-chain hydrocarbon groups, so components with high affinity to the fixing roller can be quickly found. Due to the orientation, the release effect itself will not decrease.

  In addition, since the compound of the present invention is dispersed in the toner while maintaining a certain degree of affinity due to the presence of the ester group of the long-chain aliphatic hydrocarbon, it can be dispersed in the toner with a fine domain structure and separated. The mold effect can be exhibited easily.

  Since the toner having a small particle size and monodisperse has a small heat capacity, it is necessary to suppress variations in the releasing effect of the toner itself. For this reason, by using the release agent of the present invention, it is possible to obtain a microscopic and uniform dispersion, and to exert a release effect even when a small particle size and monodisperse toner is used.

  Due to the mechanism as described above, the effect as a release agent in low-temperature fixing is sufficiently exerted, and since an ether group is present in addition to an ester group as a polar group, in addition to the release effect of a long-chain hydrocarbon group, Fixability can also be improved.

  Also, as described above, good chargeability is exhibited in the polymerization method toner, and the presence of a polar group in the release agent makes it easier to exist on the surface side of the toner particles, so that the chargeability rising effect is exhibited. It is inferred.

  In the present invention, for example, even when fixing is performed at a low surface temperature of about 100 ° C., the toner image does not peel off from the transfer material, and the electrostatic charge image exhibits good adhesion to the transfer material. Development toner and an image forming method using the same can be provided.

  Further, even when the toner of the present invention is used for image formation such as continuous printing of hundreds of thousands of sheets, the charge rise performance does not fluctuate, so that high durability and high fog-free images can be obtained. Toner for developing an electrostatic charge image and an image forming method using the same can be provided.

  The present invention relates to an electrostatic image developing toner (hereinafter also simply referred to as toner) containing the compound represented by the general formula (1) and an image forming method using the same. The compounds used, the toner production method, the image forming method, etc. will be further described.

  The compound represented by the general formula (1) used in the present invention is an ester compound composed of a long-chain aliphatic alcohol component and a malic acid component.

(Wherein, R ₁ and R ₂ represent an alkyl group which may have a substituent group having 10 to 30 carbon atoms, a X mother, H or -CO-R _4. In addition, R ₄ is the number of carbon atoms Represents an alkyl group which may have 1 to 4 substituents.)
Specifically, it has two long-chain aliphatic hydrocarbon ester groups and further has a short aliphatic hydrocarbon ester group or hydroxyl group in the molecule. In the formula, R ₁ and R ₂ may have the same structure or may have different structures.

  Specific examples of the ester compound having the specific structure include compounds shown in the following (1) to (8).

  The ester compound having a specific structure used in the present invention can be prepared, for example, by a dehydration condensation reaction between a polycarboxylic acid and a long-chain aliphatic alcohol having 10 to 30 carbon atoms.

  When the mixture is formed by changing the total carbon number of the compound represented by the general formula (1), the difference between the total carbon number of the ester compound other than the main component is 10 with respect to the total carbon number of the main component ester compound. It is preferable that it is less than. The reason for this is not clear, but when the materials having significantly different total carbon numbers are mixed together, a difference in solubility is likely to occur. Therefore, the effect of promoting dissolution in a mixture of compounds obtained by mixing is increased. It is presumed to be reduced.

  The content (ratio) of the ester compound having a specific structure used in the present invention is preferably 1 to 15% by mass and more preferably 3 to 12% by mass with respect to the whole toner.

  By setting the content of the ester compound having a specific structure within the above range, the release effect and the charge rising function can be satisfactorily exhibited.

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

  The toner of the present invention is preferably obtained by polymerizing at least a polymerizable monomer in an aqueous medium. In this production method, a polymerizable monomer is polymerized by a suspension polymerization method to prepare resin particles, or the monomer is added in a liquid (in an aqueous medium) to which an emulsion of necessary additives is added. Emulsion polymerization or miniemulsion polymerization is performed to prepare fine resin particles, and if necessary, charge control resin particles are added, and then the resin particles are aggregated by adding a coagulant such as an organic solvent or salts. It is manufactured by the method of fusing.

<Suspension polymerization method>
As an example of a method for producing the toner of the present invention, a compound of the present application, a coloring agent necessary as a component of the toner, a charge control agent, and various constituent materials such as a polymerization initiator are added to the polymerizable monomer. Then, various constituent materials are dissolved or dispersed in the polymerizable monomer using a homogenizer, a sand mill, a sand grinder, an ultrasonic disperser or the like. The polymerizable monomer in which these various constituent materials are dissolved or dispersed is dispersed in oil droplets of a desired size as a toner in an aqueous medium containing a dispersion stabilizer using a homomixer or a homogenizer. Subsequently, the suspension is polymerized by heating, and after the polymerization is completed, the dispersion stabilizer is removed, filtered, washed, and further dried to prepare the toner of the present invention. In the present invention, the “aqueous medium” refers to a medium containing at least 50% by mass of water.

<Emulsion polymerization method>
Further, as another method for producing the toner of the present invention, a method in which resin particles are prepared by salting out / fusion in an aqueous medium can also be mentioned. The method is not particularly limited, and examples thereof include methods disclosed in JP-A-5-265252, JP-A-6-329947, and JP-A-9-15904. That is, a method of salting out, agglomerating, and fusing a plurality of fine particles composed of resin particles and colorants, or resin particles and colorants, especially in water using an emulsifier. Then, a coagulant with a critical coagulation concentration or higher is added for salting out, and at the same time, the formed polymer is heated and fused at a temperature higher than the glass transition temperature of the polymer itself to gradually grow the particle size while forming fused particles. When the desired particle size is reached, a large amount of water is added to stop particle size growth, and the shape is controlled by smoothing the particle surface while heating and stirring, and the particles are heated in a fluidized state while containing water. By drying, the toner of the present invention can be formed. Here, a solvent that is infinitely soluble in water, such as alcohol, may be added simultaneously with the flocculant.

  In the method for producing a toner according to the present invention, the ester compound having the specific structure described above is dissolved or dispersed in a polymerizable monomer, and then finely dispersed in an aqueous medium, and the polymerizable monomer is polymerized by a miniemulsion polymerization method. A method in which the composite resin fine particles formed through the step of polymerizing the monomer and the colorant particles are salted out / fused is preferably used. When the ester compound having the specific structure described above is dissolved in the polymerizable monomer, the compound may be dissolved and dissolved, or may be melted and dissolved.

  As a method for producing the toner according to the present invention, a step of salting out / fusing the composite resin fine particles obtained by the multistage polymerization method and the colorant particles is preferably used.

  Next, an example of a preferable toner production method (emulsion polymerization association method) will be described in detail.

This manufacturing method includes
(1) Dissolution / dispersion step for dissolving or dispersing the ester compound in the radical polymerizable monomer (2) Polymerization step for preparing a dispersion of resin fine particles (3) Resin fine particles and colorant particles in an aqueous medium Fusion process for obtaining colored particles (associated particles) by fusion (4) Cooling process for cooling the dispersion of colored particles (5) Solid-liquid separation of the colored particles from the cooled dispersion of colored particles, Cleaning step for removing surfactants from the colored particles (6) Drying step for drying the washed colored particles If necessary, (7) A step of adding an external additive to the dried colored particles is included.

  Hereinafter, each step will be described.

[Dissolution / dispersion process]
This step is a step of preparing a radical polymerizable monomer solution of the ester compound by dissolving the ester compound in the radical polymerizable monomer.

[Polymerization process]
In a preferred example of this polymerization step, a radical polymerizable monomer solution in which the ester compound is dissolved or dispersed in an aqueous medium containing a surfactant having a critical micelle concentration (CMC) or less is added, The target energy is 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 means for applying mechanical energy include means for applying strong stirring or ultrasonic vibration energy such as homomixer, ultrasonic wave, and manton gorin.

  By this polymerization step, resin fine particles containing an ester compound 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. Further, when using uncolored resin fine particles, a dispersion of colorant fine particles is added to a dispersion of resin fine particles in a fusing step described later, and the resin fine particles and the colorant fine particles are fused. It can be set as colored particles.

[Fusion process]
As a method of fusing in the fusing step, a salting out / fusing method using resin fine particles (colored or non-colored resin fine particles) obtained in the polymerization step is preferable. In the fusing step, resin fine particles and colorant fine particles as well as internal additive fine particles such as release agent fine particles and charge control agents can be fused.

  The “aqueous medium” in the fusing step refers to a material whose main component (50% by mass or more) is 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. Among these, alcohol-based organic solvents such as methanol, ethanol, isopropanol, and butanol, which are organic solvents that do not dissolve the resin, are particularly preferable.

  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. Examples thereof include a medium type disperser. Examples of the surfactant used include the same surfactants as those described above. 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 separated by filtration, washed and filtered with the same solvent, and dried to obtain a colorant (pigment) treated with the surface modifier.

  The salting-out / fusion method, which is a preferable fusing method, is a method in which a salting-out agent composed of an alkali metal salt, an alkaline earth metal salt, or the like is added to water having resin fine particles and colorant fine particles in excess of the critical aggregation concentration. The step of adding as a flocculant and then proceeding to salting out by heating to a temperature above the glass transition point of the resin fine particles and above the melting peak temperature (° C.) of the compound, and simultaneously performing fusion. It is. In this step, an organic solvent that is infinitely soluble in water may be added to effectively reduce the glass transition temperature of the resin fine particles to effectively perform fusion. 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. Further, examples of the salt include chlorine salts, bromine salts, iodine salts, carbonates, sulfates and the like. Furthermore, examples of the organic solvent that is infinitely soluble in water include methanol, ethanol, 1-propanol, 2-propanol, ethylene glycol, glycerin, acetone and the like, but methanol, ethanol, 1-propanol having 3 or less carbon atoms. 2-propanol is preferable, and 2-propanol is particularly preferable.

  When fusing is performed by salting out / 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. 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.

  In the present invention, 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 be not lower than the glass transition temperature of the resin fine particles and the melting peak temperature (° C.) of the compound. ) Heat to above temperature. 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 (colored particles) formed by salting out / fusion of resin fine particles and arbitrary fine particles is obtained.

[Cooling process]
This step is a step of cooling (rapid cooling) the dispersion of colored particles. 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 this solid-liquid separation / washing step, a solid-liquid separation process for solid-liquid separation of the colored particles from the dispersion of colored particles cooled to a predetermined temperature in the above-described step, and a solid-liquid separated toner cake (in a wet state) A cleaning treatment for removing deposits such as a surfactant and a salting-out agent from an aggregate obtained by agglomerating certain colored particles into a cake is performed. 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 colored 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 water content of the dried colored particles is preferably 5% by mass or less, more preferably 2% by mass or less. In addition, when the dried colored particles 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 colored 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 3 to 9 μm in terms of volume median particle diameter (volume D50% diameter). The volume median diameter can be measured and calculated using a device in which a computer system for data processing (manufactured by Beckman Coulter) is connected to Coulter Multisizer II (manufactured by Beckman Coulter, Inc.).

  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, release agent, 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.

(Coloring agent)
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 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.

(Release agent)
In this invention, the ester compound which has the specific structure of this invention is used as a mold release agent. However, other mold release agents may be used in combination. In that case, it is preferable to contain 1-15 mass% of all mold release agents with respect to the whole toner, and 3-12 mass% is more preferable. By including this amount, good results can be obtained.

(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)
To the toner of the present invention, so-called external additives can be added and used for the purpose of improving fluidity, chargeability and cleaning property. These external additives are not particularly limited, and various inorganic fine particles, organic fine particles and lubricants can be used.

  A conventionally well-known thing can be used as an inorganic fine particle. Specifically, silica, titania, alumina, strontium titanate fine particles and the like can be preferably used. These inorganic fine particles may be hydrophobized if necessary. Specific examples of the silica fine particles include commercially available products R-805, R-976, R-974, R-972, R-812, R-809 manufactured by Nippon Aerosil Co., Ltd., HVK-2150, H- manufactured by Hoechst. 200, commercial products TS-720, TS-530, TS-610, H-5, MS-5 and the like manufactured by Cabot Corporation.

  As titania fine particles, for example, commercially available products T-805 and T-604 manufactured by Nippon Aerosil Co., Ltd., commercially available products MT-100S, MT-100B, MT-500BS, MT-600, MT-600SS, JA- 1. Commercial products TA-300SI, TA-500, TAF-130, TAF-510, TAF-510T manufactured by Fuji Titanium Co., Ltd. Commercial products IT-S, IT-OA, IT-OB, IT- manufactured by Idemitsu Kosan Co., Ltd. OC etc. are mentioned.

  Examples of the alumina fine particles include commercial products RFY-C and C-604 manufactured by Nippon Aerosil Co., Ltd. and commercial products TTO-55 manufactured by Ishihara Sangyo Co., Ltd.

  As the organic fine particles, spherical organic fine particles having a number average primary particle diameter of about 10 to 2000 nm can be used. Specifically, homopolymers such as styrene and methyl methacrylate and copolymers thereof can be used.

  The addition amount of these external additives 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.

(Lubricant)
If necessary, the toner of the present invention may be used with a lubricant added for the purpose of improving the cleaning property and the transfer property. Examples of lubricants include, for example, zinc stearate, aluminum, copper, magnesium, calcium, etc., zinc oleate, manganese, iron, copper, magnesium, etc., zinc palmitate, copper, magnesium, calcium, etc. And salts of higher fatty acids such as zinc of linoleic acid, salts of calcium, etc., zinc of ricinoleic acid, salts of calcium, etc.

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

  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 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. The resin for constituting the resin-dispersed carrier is not particularly limited, and known resins can be used. For example, styrene-acrylic resin, polyester resin, fluorine resin, phenol resin, etc. are 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.

  The toner of the present invention is preferably used in an image forming apparatus of a contact heating fixing system that fixes a transfer material on which a toner image is formed by passing between heating members constituting the fixing apparatus.

  Next, the image forming apparatus and the fixing device will be described.

  FIG. 1 is a cross-sectional view showing an example of an image forming apparatus used in the present invention.

  In FIG. 1, 20Y (20M, 20C, 20Bk) is an image forming unit, 21Y (21M, 21C, 21Bk) is a photosensitive drum, 22Y (22M, 22C, 22Bk) is a scorotron charger, and 23Y (23M, 23C, 23Bk). ) Is an exposure optical system, 24Y (24M, 24C, 24Bk) is a developing device, 25Y (25M, 25C, 25Bk) is a cleaning device, 34Y (34M, 34C, 34Bk) is a transfer device, 40 is a fixing device, and 115 is a transfer device. A material conveying belt, 160 is a conveying portion, and P is a transfer material.

  Hereinafter, the image forming apparatus of FIG. 1 will be described.

  In the image forming apparatus of FIG. 1, four sets of image forming units 20Y, 20M, 20C, and 20Bk are provided along the transfer material conveyance belt 115.

  Each image forming unit includes a photosensitive drum 21Y (21M, 21C, 21Bk), a scorotron charger 22Y (22M, 22C, 22Bk), an exposure optical system 23Y (23M, 23C, 23Bk), and a developer 24Y (24M, 24C, 24Bk) and a cleaning device (cleaning means) 25Y (25M, 25C, 25Bk), each toner image formed on the photosensitive drum (21Y, 21M, 21C, 21Bk) of each image forming unit is timed. The transfer material (transfer paper, OHP, etc.) P conveyed together is sequentially transferred by a transfer device 34Y (34M, 34C, 34Bk) as transfer means to form a superimposed color toner image.

  The transfer material P is transported on the transfer material transport belt 115, and is a separation member provided in the transport unit 160 at a predetermined interval with a charge eliminating action by a paper separation AC neutralizer 161 as a transfer material separating means. It is separated from the conveyor belt by the claw 210.

  Next, the transfer material P passes through the transport unit 160, and is then transported to a fixing device (fixing unit) 40 including the heating roller 41 and the pressure roller 42, and the heat roller 41 and the pressure roller 42 perform the transfer material P. The transfer material P is sandwiched by the nip portion T to be formed, and heat and pressure are applied to fix the superimposed toner image on the transfer material P, and then discharged outside the apparatus.

  As the image exposure light source, a scanning optical system using a semiconductor laser, a solid state scanner such as an LED or a liquid crystal shutter, and the like can be used as the exposure means.

  The transfer material transport belt 115 for transporting the transfer material is made conductive by adding a conductive filler such as carbon black to a polymer film such as polyimide, polycarbonate, PVdF, or a synthetic rubber such as silicon rubber or fluorine rubber. Are used, and either a drum shape or a belt shape may be used, but a belt shape is preferable from the viewpoint of the degree of freedom in device design.

  The surface of the transfer belt is preferably appropriately roughened. By setting the 10-point surface roughness Rz of the transfer belt to 0.5 to 2 μm, the adhesion between the transfer material and the transfer belt is improved, and the transfer material is prevented from swinging on the transfer belt. Transferability of the toner image to the toner can be improved.

  The 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 that contacts 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 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 °.

  The thickness of the coating layer 82 made of an elastic body is preferably 0.1 to 30 mm, and more preferably 0.1 to 20 mm.

  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 of a type using a belt and a heating roller in order to secure a nip width. The fixing roller 601, the seamless belt 11, and the pressure that is pressed against the fixing roller 601 through 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 fixing roller 601 is formed by forming a heat-resistant elastic 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 fixing 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 fixing roller 601 is adjusted to a constant temperature. The seamless belt 11 contacts the fixing 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 disposed in a state of being pressed against the fixing roller 601 via 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 can smoothly slide and rotate. 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.

  The 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 the 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 heat and pressure are applied through the nip portion N to fix the toner image on the transfer material P. In the above description, a halogen lamp 14 (not shown) as a heating member may be disposed inside the soft roller 17b.

  The present invention will be specifically described below with reference to examples, but the embodiments of the present invention are not limited to these examples.

<Preparation of ester compound with specific structure>
The compounds of the ester compounds (1) to (8) were prepared by dehydrating and condensing polyvalent carboxylic acid and a long-chain aliphatic alcohol having 10 to 30 carbon atoms.

  The reaction is carried out at 220 ° C. for 8 hours in a nitrogen atmosphere, cooled to 80 ° C. at a cooling rate of 20 ° C./min after completion of the reaction, neutralized with an aqueous potassium hydroxide solution, then washed, dehydrated and filtered. This produced the above compound.

<Production of toner>
(Preparation of colored particles Bk1)
(1) Synthesis of low molecular weight latex:
In a 4-liter Kolben with a capacity of 1 liter equipped with a stirrer, a condenser and a temperature sensor, 509.83 g of styrene, 88.67 g of n-butyl acrylate, 34.83 g of methacrylic acid, 21.83 g of tert-dodecyl mercaptan, Then, 66.7 g of “ester compound (1)” was added, the internal temperature was raised to 80 ° C., and the mixture was stirred until “ester compound (1)” was dissolved, and the temperature was maintained as it was. On the other hand, an aqueous surfactant solution in which 1.0 g of sodium dodecylbenzenesulfonate was dissolved in 2700 ml of pure water was similarly heated to an internal temperature of 80 ° C. and held as it was. While stirring the surfactant aqueous solution kept at 80 ° C., a monomer solution in which the “ester compound (1)” was dissolved was added, and emulsification was performed using an ultrasonic emulsifier to obtain an emulsion. Next, the emulsion is put into a 5-liter four-headed colven equipped with a stirrer, a cooling pipe, a nitrogen introduction pipe and a temperature sensor, and the internal temperature is maintained at 70 ° C. under a nitrogen stream while stirring. Then, a polymerization initiator aqueous solution in which 7.52 g of ammonium persulfate was dissolved in 500 ml of pure water was added and polymerization was performed for 4 hours, followed by cooling to room temperature and filtration to obtain a latex. After the reaction, no polymerization residue was observed, and a stable latex was obtained. This is referred to as “latex (L-1)”.

  The obtained “latex (L-1)” was measured to have a number average primary particle size of 125 nm using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.). The glass transition temperature measured by DSC was 58 ° C. Moreover, the solid content concentration of the latex measured by a mass method by standing drying was 20% by mass.

(2) Synthesis of high molecular weight latex In a four-headed Kolben having a capacity of 500 milliliters equipped with a stirrer, a cooling tube and a temperature sensor, 92.47 g of styrene, 30.4 g of n-butyl acrylate, 3.80 g of methacrylic acid, Add 0.12 g of tert-dodecyl mercaptan and 13.34 g of “ester compound (1)”, raise the internal temperature to 80 ° C., and stir until the “ester compound (1)” is dissolved. Held. On the other hand, an aqueous surfactant solution in which 0.27 g of sodium dodecylbenzenesulfonate was dissolved in 540 ml of pure water was similarly heated to an internal temperature of 80 ° C. and kept as it was. While stirring the surfactant aqueous solution kept at 80 ° C., a monomer solution in which the “ester compound (1)” was dissolved was added, and emulsification was performed using an ultrasonic emulsifier to obtain an emulsion. Next, the emulsion is put into a 5-liter four-headed colven equipped with a stirrer, a cooling pipe, a nitrogen introduction pipe and a temperature sensor, and the internal temperature is maintained at 70 ° C. under a nitrogen stream while stirring. Then, a polymerization initiator aqueous solution in which 0.27 g of ammonium persulfate was dissolved in 100 ml of pure water was added, followed by polymerization for 4 hours, followed by cooling to room temperature and filtration to obtain a latex. After the reaction, no polymerization residue was observed, and a stable latex was obtained. This is referred to as “latex (H-1)”.

  The obtained “latex (H-1)” was measured to have a number average primary particle size of 108 nm using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.). Moreover, it was 59 degreeC when the glass transition temperature was measured by DSC. Moreover, the solid content concentration of the latex measured by a mass method by standing drying was 20% by mass.

(3) Preparation of colored particles Bk Four-headed Kolben with a capacity of 5 liters equipped with a stirrer, a cooling tube and a temperature sensor, 250 g of latex (H-1), 1000 g of latex (L-1), and 900 ml of pure water And a carbon black dispersion obtained by dispersing 20 g of carbon black “Regal 330R” (manufactured by Cabot) in a surfactant aqueous solution (aqueous solution in which 9.2 g of sodium dodecyl sulfate is dissolved in 160 ml of pure water) and stirring. While adding 5 mol / liter of sodium hydroxide aqueous solution, the pH was adjusted to 10. Further, an aqueous solution in which 28.5 g of magnesium chloride hexahydrate was dissolved in 1000 ml of pure water was added at room temperature while stirring, and then the temperature was raised until the internal temperature reached 95 ° C. While maintaining the internal temperature at 95 ° C., the particle size of the dispersed particles was measured using “Coulter Counter II” (manufactured by Coulter Co.). When the particle size reached 6.5 μm, 80.6 g of sodium chloride was obtained. An aqueous solution in which 700 ml of pure water was dissolved was added, and the reaction was continued for 6 hours while maintaining the internal temperature at 95 ° C. After completion of the reaction, the resulting dispersion of associated particles (95 ° C.) was cooled to 45 ° C. for 10 minutes (cooling rate = 5 ° C./min). The associated particles (colored particles Bk) thus produced were filtered, washed by repeating resuspension in pure water and filtration, and then dried to produce colored particles Bk. This is designated as “colored particles Bk1”. When the particle size of “colored particles Bk1” was measured using “Coulter Counter II” (manufactured by Coulter, Inc.), the volume median particle size (D ₅₀ ) = 6.5 μm and the CV value = 18.2%.

(Preparation of colored particles Bk2)
“Colored particle Bk2” was prepared in the same manner except that 66.7 g of “ester compound (1)” used in the production of “colored particle Bk1” was changed to 100.0 g.

(Preparation of colored particles Bk3)
“Colored particle Bk3” was prepared in the same manner except that 66.7 g of “ester compound (1)” used in the production of “colored particle Bk1” was changed to 20.0 g.

(Preparation of colored particles Bk4)
“Colored particle Bk4” was prepared in the same manner except that “ester compound (1)” used in the production of “colored particle Bk1” was changed to “ester compound (2)”.

(Preparation of colored particles Bk5)
“Colored particle Bk5” was prepared in the same manner except that “ester compound (1)” used in the production of “colored particle Bk1” was changed to “ester compound (3)”.

(Preparation of colored particles Bk6)
“Colored particle Bk6” was prepared in the same manner except that “ester compound (1)” used in the production of “colored particle Bk1” was changed to “ester compound (4)”.

(Preparation of colored particles Bk7)
“Colored particle Bk7” was prepared in the same manner except that “ester compound (1)” used in the production of “colored particle Bk1” was changed to “ester compound (5)”.

(Preparation of colored particles Bk8)
“Colored particle Bk8” was prepared in the same manner except that “ester compound (1)” used in the production of “colored particle Bk1” was changed to “ester compound (6)”.

(Preparation of colored particles Bk9)
“Colored particle Bk9” was produced in the same manner except that “ester compound (1)” used in the production of “colored particle Bk1” was changed to “ester compound (7)”.

(Preparation of colored particles Bk10)
“Colored particle Bk10” was prepared in the same manner except that “ester compound (1)” used in the production of “colored particle Bk1” was changed to “ester compound (8)” alone.

(Preparation of colored particles Bk11)
“Colored particle Bk11” was prepared in the same manner except that “ester compound (1)” used in the production of “colored particle Bk1” was changed to “carnauba wax”.

(Preparation of colored particles Bk12)
“Colored particle Bk12” was prepared in the same manner except that “ester compound (1)” used in the production of “colored particle Bk1” was changed to “low molecular weight polypropylene”.

(Preparation of colored particles C1 to C12)
“Toner particle particle C1” was similarly used except that 20 g of “Regal 330R” (manufactured by Cabot) used in the production of “colored particles Bk1 to Bk12” was changed to 10 g of “CI Pigment Blue 15: 3”. To C12 ".

(Preparation of colored particles M1 to M11)
“Toner particle particles C1 to C12” were similarly used except that 20 g of “Legal 330R” (Cabot Corporation) used in the production of “colored particles Bk1 to Bk12” was changed to 17 g of “CI Pigment Red 122”. Was made.

(Preparation of colored particles Y1 to Y12)
“Colored particles C1 to C11” in the same manner except that 20 g of “Legal 330R” (manufactured by Cabot) used in the production of “colored particles Bk1 to Bk12” was changed to 18 g of “CI Pigment Yellow 17”. Was made.

Table 1 shows the ester compound, volume median particle diameter (D ₅₀ ), and CV value used for the production of “colored particles Bk1 to 12”.

  Note that “colored particles C1 to C12”, “colored particles M1 to M12”, and “colored particles Y1 to Y12” are omitted because the measurement results are the same as the measurement results of “colored particles Bk1 to Bk12”.

(External additive treatment of colored particles)
Subsequently, 1% by mass of hydrophobic silica (number average primary particle size: 12 nm, hydrophobization degree: 68) and hydrophobic titanium oxide (number average primary particle size: 20 nm, hydrophobization degree) are prepared on each colored particle prepared above. : 63) 1 mass% was added, and it mixed for 10 minutes using "Henschel mixer" (made by Mitsui Miike Chemical Co., Ltd.). Thereafter, coarse particles were removed using a 45 μm sieve to prepare “Toners Bk1 to Bk12”, “Toners C1 to C12”, “Toners M1 to M12”, and “Toners Y1 to Y12”.

<Preparation of developer>
Each of the toners produced above is mixed with a silicon carrier-coated ferrite carrier having a volume average particle diameter of 60 μm so that the concentration of the toner is 6% by mass, “Developers Bk1 to Bk12”, “Developers” C1-C12 "," Developers M1-M12 "and" Developers Y1-Y12 "were prepared.

<Evaluation equipment>
As the evaluation device, the image forming apparatus shown in FIG. 1 was used with the fixing device shown in FIG. The fixing speed and fixing speed were set to 280 mm / sec (about 50 sheets / A4 plate, lateral feed).

  A surface temperature of the heating roll that can be arbitrarily set at 90 to 240 ° C. was used.

<Evaluation>
Using the evaluation device, each toner and developer prepared above were loaded in order, printed, and the following items were evaluated.

<Evaluation of fixing temperature>
Fixable temperature is evaluated by changing the surface temperature of the transfer material immediately after discharging from the heat roll from 90 ° C to 200 ° C in increments of 10 ° C in an environment of normal temperature and normal humidity (20 ° C, 50% RH). I went there. As the transfer material, A4 quality paper (65 g / m ² ) was used.

For fixing temperature, the fixing strength of the obtained fixed image is determined using a method according to the mending tape peeling method described in Chapter 9 Section 1.4 of “Basics and Applications of Electrophotographic Technology: Electrophotographic Society”. Asked. Specifically, after changing the surface temperature of the transfer material to produce a 2.54 cm square solid fixed image with a toner adhesion amount of 0.6 mg / cm ² , the “Scotch Mending Tape” (Sumitomo 3M Image density before and after peeling was measured, and the residual ratio of the image density was determined as the fixing rate.

Tape peeling method 1) Measure absolute reflection density D ₀ of 5 mm square solid black 2) Lightly affix “Mending tape” (manufactured by Sumitomo 3M: No.810-3-12) 3) Pressure of 1 kPa 4) The tape is peeled back and forth 3.5 times. 4) The tape is peeled off at an angle of 180 ° with a force of 200 g. 5) The absolute reflection density D ₁ after peeling is measured. 6) Fixing rate = 100 × D ₁ / D ₀ (% )
A fixing temperature at which a fixing rate of 90% or more was obtained was evaluated as a fixing possible temperature. For the measurement of the image density, a reflection densitometer “RD-918” (manufactured by Macbeth) was used.

<Evaluation of fixing offset>
The surface temperature of the hot roll was set to 150 ° C.

Fixing offset was adjusted in a low-temperature, low-humidity environment (10 ° C., 20% RH) using a full-color image (line image with a total pixel ratio of 40% (each color 10%)). By continuously printing 1000 sheets of A4 quality paper (65 g / m ² ), directly observing the image after 1000 sheets of printing and on the surface of the hot roll, and by the adhesion of toner generated on the printed image and the surface of the hot roll. Evaluation was based on the degree of offset. The surface temperature of the transfer material was confirmed to be around 100 ° C. immediately after discharge.

Evaluation Criteria A: Good with no occurrence of offset on the image and on the surface of the hot roll ○: Not seen on the image but with an offset on the hot roll (no problem in practice)
×: Dirt due to offset occurs on the image (there is a practical problem)
《Image evaluation》
An original with a 5% pixel rate for all colors using high-quality paper (65 g / m ² ) in A4 size in an environment of normal temperature and humidity (20 ° C, 50% RH) with a hot roll surface temperature of 150 ° C. After intermittently printing 100,000 sheets, the image density and fogging printed on the first sheet and the 100th continuous sheet after standing overnight were evaluated.

<Image density>
The density of the solid black image portion was evaluated by a relative density (the density of a transfer material not printed is 0.00). The measurement was performed using a Macbeth reflection densitometer “RD-918” (manufactured by Macbeth Co., Ltd.).

<Cover>
The fog density was measured as the relative density of the white background portion of the print when the white background portion of the unused transfer material was set to a reflection density of 0.000. The measurement was performed using a Macbeth reflection densitometer “RD-918” (manufactured by Macbeth).

  The evaluation results are shown in Table 2.

  As is apparent from Table 2, images formed with “Developers Bk1 to Bk10”, “Developers C1 to C10”, “Developers M1 to M10” and “Developers Y1 to Y10” in the present invention All of the evaluation items are excellent, but images formed with “toner Bk11, Bk12”, “toner C11, C12”, “toner M11, M12”, and “toner Y11, Y12” outside the present invention are evaluated items. It turns out that there are some problems.

1 is a cross-sectional view illustrating an example of an image forming apparatus used in the present invention. FIG. 3 is a cross-sectional view illustrating an example of a fixing device (a type using a pressure roller and a heating roller) used in the present 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. FIG. 3 is a schematic diagram illustrating an example of a fixing device (a type using a soft roller and a heating roller) used in the present invention.

Explanation of symbols

20Y (20M, 20C, 20Bk) Image forming unit 21Y (21M, 21C, 21Bk) Photosensitive drum 22Y (22M, 22C, 22Bk) Scorotron charger 23Y (23M, 23C, 23Bk) Exposure optical system 24Y (24M, 24C, 24Bk) Developing device 25Y (25M, 25C, 25Bk) Cleaning device 34Y (34M, 34C, 34Bk) Transfer device 40 Fixing device 115 Transfer material transport belt 160 Transport section P Transfer material

Claims (2)

An electrostatic charge image developing toner containing at least a binder resin and a colorant, wherein the electrostatic charge image developing toner contains at least one compound represented by the following general formula (1).

(Wherein, R ₁ and R ₂ represent an alkyl group which may have a substituent group having 10 to 30 carbon atoms, a X mother, H or -CO-R _4. In addition, R ₄ is the number of carbon atoms Represents an alkyl group which may have 1 to 4 substituents.) An image forming method, comprising: transferring a toner image formed on an electrophotographic photosensitive member using the electrostatic image developing toner according to claim 1 to a transfer material;

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