JP4548296B2 - Toner for electrostatic image development - Google Patents

Description

  The present invention relates to an electrostatic charge image developing toner, and more particularly to an electrostatic charge image developing toner containing an ester compound having a specific structure as a release agent.

  In the field of electrophotographic image forming technology such as copying machines and printers, with the progress of digital technology, recently, 1200 dpi (dpi in the present invention represents the number of dots per 2.54 cm) level. The technology of the level which reproduces a precise dot image has come to be requested.

  And, in order to faithfully reproduce such a minute dot image, the reduction in the diameter of the toner particles 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. 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 the toner in the molten state adheres to the heating member, and the offset phenomenon in which 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 varies. 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. An object of the present invention is to provide a toner for developing an electrostatic image having a sufficiently low temperature fixability that exhibits good adhesiveness and a wide fixable temperature range due to sufficient offset resistance.

  Another object of the present invention is to provide a toner for developing an electrostatic charge image having durability that does not change the charge rising performance of the toner even when, for example, large-scale printing of several hundred thousand sheets is continuously performed. To do.

  The object of the present invention is achieved by adopting the following configuration.

(1)
In the electrostatic image developing toner having at least a binder resin and a colorant, the following general formula (1)
A toner for developing an electrostatic image, comprising a compound represented by the formula:
Provided that said if an electrostatic image developing toner contains plural kinds of ester compounds represented by the following general formula (1), or an ester compound, wherein the toner for developing electrostatic images is represented by the following general formula (1) The case where the ester compound represented by the general formula (X) and / or the general formula (Y) is contained is excluded.

(In General Formula (1) , X represents H or —CO—R ₄ , R ₄ represents an alkyl group having 1 to ₄ carbon atoms , and R _{1 to} R ₃ represent an alkyl group having 10 to 30 carbon atoms . )
(In the general formula _{(X), R 1, R} 2 and _{R 3} charcoal represents an alkyl group which may have a substituent group having 10 to 30 carbon atoms.)
(In general formula (Y), R ₄ and R ₅ represent an alkyl group which may have a substituent having 10 to 30 carbon atoms.)

  In the present invention, a toner image is produced even when fixing is performed at a low surface temperature of about 100 ° C., for example, with a toner for developing an electrostatic image containing the compound represented by the general formula (1). It is possible to provide a toner for developing an electrostatic charge image that does not peel off from the transfer material and exhibits good adhesion to the transfer material.

  In addition, the toner of the present invention is used for developing a highly durable electrostatic image that can produce a high-density and non-fogging image even if it is used for image formation such as continuous printing of hundreds of thousands of sheets. The toner 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). The present inventor uses a toner containing an ester compound of a higher fatty acid represented by the above general formula (1) (hereinafter also referred to as an ester compound having a specific structure), for example, the surface temperature of the transfer material is around 100 ° C. It has been found that when used in an image forming apparatus for fixing at a temperature, the toner image does not peel off from the transfer material and exhibits a strong fixing performance.

  As described above, it is not clear why the toner compound contains an ester compound having a specific structure, so that even if it is fixed at a low temperature, it exhibits a strong fixing performance. However, the ester compound structure has one carbon atom. Due to the presence of ester groups and hydroxyl groups of -4 short aliphatic hydrocarbons, the ester compound is moderately oriented to the cellulose molecules constituting the transfer material, resulting in improved adhesion between the transfer material and the toner. It is guessed.

  Further, even when a large amount of printing of several hundred thousand sheets was continuously performed using the toner of the present invention, the toner charge rising performance did not fluctuate. The reason why the durability to maintain the charge rising performance is obtained even when a large amount of continuous processing is performed with a toner containing an ester compound having a specific structure is not clear, but is probably due to the following reason. In the case of a toner that easily retains a large amount of water in the structure, such as a polymerized toner produced through a polymerization process in an aqueous medium, the ester compound is a water group such as an ester group bonded to a hydroxyl group or a hydrocarbon group having a small number of carbon atoms. Since it has a structure in which a substituent having a high affinity for is present in the center of the molecule, it has a structure that is easily oriented to water with a quaternary carbon bonded to the substituent as the center. Guessed. The presence of an ester compound in which hydrophilic substituents are orientated outward on the surface of the toner particles is presumed to exhibit a charge rising effect due to polar groups in the ester compound.

  As described above, in the toner of the present invention, the ester compound having the specific structure exhibits appropriate orientation with respect to cellulose molecules and water molecules, so that good fixing performance is exhibited even when fixing at low temperature. It is presumed that the toner charge rising can be stably maintained even when a large amount of printing is continuously performed.

  Furthermore, although the toner of the present invention exhibits good releasability, the compound represented by the general formula (1) includes a plurality of long-chain hydrocarbon groups having 10 to 30 carbon atoms due to ester bonds. Because it contains, some degree of affinity is expressed between the ester compounds, and it is assumed that a good release effect is expressed by dispersing while forming a fine domain structure in the toner particle by the action of this affinity. Is done.

  Hereinafter, the present invention will be described in detail.

  The toner of the present invention has at least a binder resin and a colorant, and contains an ester compound having a specific structure.

  The ester compound having a specific structure used in the present invention is an ester compound of citric acid having a long-chain aliphatic alcohol component represented by the following general formula (1).

(In General Formula (1) , X represents H or —CO—R ₄ , R ₄ represents an alkyl group having 1 to ₄ carbon atoms, and R _{1 to} R ₃ represent an alkyl group having 10 to 30 carbon atoms . )
Specifically, it has three long-chain aliphatic hydrocarbon ester groups and further has a short aliphatic hydrocarbon ester group or hydroxyl group in the molecule. The alkyl group of R _{1 to} R ₄ preferably has no substituent, but may have a substituent, and examples of the substituent include a sulfonic acid, a nitro group, an amino group, and a hydroxyl group.

  Examples of the ester compound having the specific structure include the following compounds (1) to (10).

  The ester compound having a specific structure can be prepared by a known method. For example, the ester compound having a specific structure is prepared by a dehydration condensation reaction between a polycarboxylic acid and a higher (long chain aliphatic) alcohol having 10 to 30 carbon atoms. Is preferred.

  The content (ratio) of the ester compound having a specific structure used in the present invention is preferably 1 to 15 parts by mass and more preferably 3 to 12 parts by mass with respect to 100 parts by mass of the toner.

  If the content of the ester compound having a specific structure is less than the above range, the releasability and chargeability are likely to be lowered, and if it is more than the above range, the release effect and the charge rising function can be exhibited, Adhesiveness tends to decrease slightly. Therefore, by setting the content in the above range, a wide fixable temperature range can be obtained.

  The toner of the present invention may contain a plurality of compounds represented by the general formula (1).

  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 mini-emulsion polymerization is performed to prepare fine resin particles. 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 charge control resin is dissolved in a polymerizable monomer, and various constituent materials such as a colorant, a mold release agent, and a polymerization initiator are added. 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 having a desired size as a toner in an aqueous medium containing a dispersion stabilizer using a homomixer or a homogenizer. Thereafter, the stirring mechanism is transferred to a reaction device (stirring device) which is a stirring blade described later, and the polymerization reaction is advanced by heating. After completion of the reaction, the dispersion stabilizer is removed, filtered, washed, and 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 / fusing 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 a coloring material, or a fine particle composed of a resin and a coloring agent, in particular, using water to disperse these 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 the particle size growth, and the shape is controlled by smoothing the particle surface while heating and stirring, and the particles are heated in a fluid state while containing water. By drying, the toner of the present invention can be formed. Here, a solvent that dissolves infinitely in water, such as alcohol, may be added simultaneously with the flocculant.

  In the method for producing the toner of the present invention, the compound resin fine particles and the colorant particles formed through the step of polymerizing the polymerizable monomer after the ester compound having a specific structure is dissolved in the polymerizable monomer are salted out. / The method of fusing is preferably used. When the ester compound having a specific structure is dissolved in the polymerizable monomer, the ester compound having a specific structure may be dissolved or melted or dissolved.

  In addition, as a method for producing the toner of the present invention, a step of salting out / fusing composite resin fine particles and colorant particles obtained by a multistage polymerization method 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 step of dissolving an ester compound having a specific structure in a radical polymerizable monomer (2) Polymerization step for preparing a dispersion of resin fine particles (3) Toner by fusing resin fine particles in an aqueous medium Fusing step for obtaining particles (associating particles) (4) Cooling step for cooling the dispersion of toner particles (5) Solid-liquid separation of the toner particles from the cooled dispersion of toner particles, and interfacial activity from the toner particles (6) Drying step for drying the washed toner particles If necessary, (7) A step of adding an external additive to the dried toner particles may be included.

  Hereinafter, each step will be described.

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

[Polymerization process]
In a preferred example of this polymerization step, droplets of a radical polymerizable monomer solution of the ester compound having the specific structure are formed in an aqueous medium (aqueous solution of a surfactant and a radical polymerization initiator), and the radical is formed. The polymerization reaction is advanced in the droplets by radicals from the polymerization initiator. The droplet may contain an oil-soluble polymerization initiator. In such a polymerization process, it is essential to apply a mechanical energy to forcibly emulsify (form droplets). 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 an ester compound having a specific structure 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. Thus, toner particles can be obtained.

[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. Of 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. A medium type disperser is mentioned. 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. It is added as a flocculant, and then the salting-out is progressed at the same time as the salting-out proceeds by heating to a temperature above the glass transition point of the resin fine particles and above the melting peak temperature (° C.) of the ester compound having the specific structure. This is the process of wearing. 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 so as 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. The range of the addition temperature may be not higher than the glass transition temperature of the resin, but is generally 5 to 55 ° C, preferably 10 to 45 ° C.

  Further, in the present invention, the salting-out agent is added at a temperature lower than the glass transition temperature of the resin fine particles, and then the temperature is raised as quickly as possible, and the melting temperature of the ester compound having the specific structure is higher than the glass transition temperature of the resin fine particles. Heat to a temperature above the peak temperature (° C). 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 fusing step, a dispersion of associated particles (toner particles) formed by salting out / fusing resin fine particles and arbitrary fine particles is obtained.

  The glass transition temperature of the resin particles and the melting peak temperature of the ester compound having the above specific structure are measured using a DSC-7 differential scanning calorimeter (Perkin Elmer) and a TAC7 / DX thermal analyzer controller (Perkin Elmer). It can be carried out.

  As a measurement procedure, 4.5 to 5.0 mg of toner is precisely weighed to two decimal places, enclosed in an aluminum pan (Kit No. 0219-0041), and set in a DSC-7 sample holder. The reference uses an empty aluminum pan. As measurement conditions, heat-cool-heat temperature control was performed at a measurement temperature of 0 ° C. to 200 ° C., a temperature increase rate of 10 ° C./min, and a temperature decrease rate of 10 ° C./min. Analysis based on data in Heat.

  The glass transition temperature is obtained by drawing an extension of the baseline before the rise of the endothermic peak of the resin fine particle and a tangent line indicating the maximum slope from the rising end of the endothermic peak of the resin fine particle to the peak apex, and the intersection is the glass transition point. As shown.

  The temperature of the dissociation peak indicates the peak top temperature of the endothermic peak of the ester compound as the melting peak temperature.

[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 / washing step] In this solid-liquid separation / washing step, the solid-liquid separation process for solid-liquid separation of the toner particles from the dispersion of toner particles cooled to a predetermined temperature in the above-mentioned step, and solid-liquid separation A cleaning treatment is performed to remove deposits such as a surfactant and a salting-out agent from the toner cake (cake-like aggregate). 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 step] This step is a step of drying the washed toner cake 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 due to weak interparticle attraction, the aggregate may be crushed. Here, as the crushing treatment apparatus, a mechanical crushing apparatus such as a jet mill, a Henschel mixer, a coffee mill, or a food processor can be used.

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

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

The toner of the present invention preferably has a median diameter (D ₅₀ ) in the volume-based particle size distribution of the toner particles constituting the toner of 3 to 9 μm.

Here, the median diameter (D ₅₀ ) of the toner particles refers to a toner particle diameter corresponding to a central portion in a certain particle size distribution. That is, when the particle size distribution of a certain number of toner particles is taken, the volume of toner particles having each particle diameter is counted in order from the larger or smaller particle diameter to determine the frequency, and the total toner particle volume The toner particle diameter that is a particle size distribution portion showing 50% of the toner particle diameter is called the median diameter (D ₅₀ ) of the toner particles.

  The toner of the present invention preferably has a CV value of 20% or less in the number-based particle size distribution.

  The CV value in the number-based particle size distribution used in the present invention represents the degree of dispersion in the particle size distribution of toner particles on the number basis, and is defined by the following equation. The smaller the CV value, the sharper the particle size distribution, and the larger the toner particle size.

CV value = (standard deviation in number particle size distribution) / (median diameter (D ₅₀ ) in number particle size distribution) × 100
The toner used in the present invention preferably has a CV value of 20.0 or less, more preferably 12.0 to 15.0.

The median diameter (D ₅₀ ) and CV value in the volume-based particle size distribution of the toner particles used in the present invention are determined by the Coulter Multisizer III (manufactured by Beckman Coulter) and the computer system for data processing (Beckman Coulter, Inc.). Measured and calculated using a device connected to the product.

Measurement conditions (1) Aperture: 50 μm
(2) Sample preparation method: An appropriate amount of a surfactant (neutral detergent) is added to 50 to 100 ml of an electrolytic solution “ISOTON R-II” (manufactured by Coulter Scientific Japan), and the measurement sample is 10 to 20 mg. Add This system is adjusted by dispersing for 1 minute with an ultrasonic disperser.

  The particle size distribution of the toner particles can be controlled by production conditions (for example, the composition of the resin (polymer), the flocculant used in the associative polymerization method, and the organic solvent).

  Further, as the toner, the amount of fine powder toner of 3.0 μm or less is preferably 20% by number or less based on the number-based particle size distribution, and the amount of fine powder toner of 2.0 μm or less is preferably 10% by number or less.

  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 binder resin used in the present invention, a known resin can be used. Specifically, for example, a copolymer of styrene such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene and the like; a styrene-p-chlorostyrene copolymer, a styrene-vinyltoluene copolymer, and a styrene-vinyl. Naphthalene copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene, Styrene copolymers such as vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer; polyvinyl chloride, phenol resin, naturally modified phenol resin, natural Resin-modified maleic acid tree , Acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane resin, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral resin, terpene resin, coumarone indene resin, petroleum resin, etc. it can. Among these, preferred binder resins include polyester resins and styrene copolymer resins.

  The monomers combined with the styrene monomer of the styrene copolymer include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, and phenyl acrylate. , Methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, monocarboxylic acids having a double bond such as acrylamide or its substitutes; maleic acid, butyl maleate, maleic Dicarboxylic acids having a double bond such as methyl acid and dimethyl maleate and substituted products thereof, vinyl esters such as vinyl chloride, vinyl acetate and vinyl benzoate; ethylene-based compounds such as ethylene, propylene and butylene Olefins such; vinyl methyl ketone, vinyl ketones such as vinyl hexyl ketone, vinyl methyl ether, vinyl ethyl ether, and the like vinyl ethers such as vinyl isobutyl ether. As the monomer for forming the copolymer, these vinyl monomers are used alone or in combination of two or more.

  Further, as the binder resin for toner, two or more of these resins may be mixed or crosslinked. As the crosslinking agent for the binder resin, a compound having two or more polymerizable double bonds may be used. Specifically, for example, aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; carboxylic acids having two or more double bonds such as ethylene glycol diacrylate, ethylene glycol dimethacrylate, and 1,3-butadiol dimethacrylate Esters; divinyl compounds such as divinylaniline, divinyl ether, divinyl sulfide, divinyl sulfone; compounds having three or more vinyl groups. These may be used alone or in combination of two or more.

(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 addition to the ester compound described above, other release agents can be added to the toner of the present invention. As such a release agent, a known compound can be used. Specifically, solid paraffin wax, micro wax, rice wax, fatty acid amide wax, fatty acid wax, aliphatic monoketone, fatty acid metal Examples thereof include salt waxes, fatty acid ester waxes, partially saponified fatty acid ester waxes, silicon varnishes, higher alcohols, and carnauba waxes.

  Also, polyolefins such as low molecular weight polyethylene and polypropylene can be used. Particularly, a polyolefin having a softening point of 70 to 150 ° C. by the ring and ball method is preferable, and a polyolefin having a softening point of 120 to 150 ° C. is more preferable.

  The content of the other release agent is preferably 7 parts by mass or less with respect to the whole toner, and if it exceeds 7 parts by mass, the adhesiveness to the transfer material is lowered and the low-temperature fixability is impaired.

(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 metal salts and metal complexes 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 used by mixing so-called external additives with toner particles for the purpose of improving fluidity, chargeability and cleaning properties. 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)
In the toner of the present invention, a lubricant may be mixed with toner particles for the purpose of improving the cleaning property and transferability, if necessary. 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 preferred. The median diameter (D ₅₀ ) of the carrier based on volume is preferably 15 to 100 μm, more preferably 20 to 80 μm.

The measurement of the median diameter (D ₅₀ ) based on the volume of the carrier can be measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by Sympathec).

  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.

  Further, 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 suitably used in a contact-type fixing type image forming apparatus that fixes a transfer material on which a toner image is formed by passing between heating members constituting the fixing apparatus.

  Hereinafter, the image forming apparatus and the fixing apparatus 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, 1 is a semiconductor laser light source, 2 is a polygon mirror, 3 is an fθ lens 3, 4 is a photosensitive drum, 5 is a charger, 6 is a developing device, 7 is a transfer device, and 9 is a separator (separation pole). , P is a transfer material, 10 is a fixing device, 11 is a cleaning device, 12 is pre-charge exposure (PCL), and 13 is a cleaning blade.

  The photosensitive drum 4 is formed by forming an organic photoconductor (OPC) as a photosensitive layer on the outer peripheral surface of an aluminum drum base.

  In FIG. 1, exposure light is emitted from a semiconductor laser light source 1 based on information read by a document reading device (not shown). This is distributed in the direction perpendicular to the paper surface of FIG. 1 by the polygon mirror 2 and irradiated onto the surface of the photoreceptor through an fθ lens 3 that corrects image distortion, thereby forming an electrostatic latent image. The photosensitive drum 4 is uniformly charged in advance by the charger 5 and starts to rotate clockwise in accordance with the timing of image exposure.

  The electrostatic latent image on the surface of the photosensitive drum is developed by the developing device 6, and the formed developed image is transferred to the transfer material P that has been transported in time by the action of the transfer device 7. Further, the photosensitive drum 4 and the transfer material P are separated by a separator (separation pole) 9, but the developed image is transferred and supported on the transfer material P, guided to the fixing device 10, fixed, and carried out of the device. The

  Untransferred toner or the like remaining on the surface of the photoreceptor is cleaned by a cleaning device 11 of a cleaning blade type, removed residual charge by pre-charge exposure (PCL) 12, and again by the charger 5 for the next image formation. Uniformly charged.

  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 a transfer paper. Specifically, various transfer materials such as 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, plastic film for OHP, cloth, etc. However, it is not limited to these.

  The cleaning blade 13 uses a rubber-like elastic body having a thickness of about 1 to 30 mm, and urethane rubber is most often used as the material. Since this is used in pressure contact with the photoconductor, it is easy to transfer heat. In the present invention, it is desirable to provide a release mechanism and keep it away from the photoconductor when no image forming operation is performed.

  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 shown in FIG. 3 is a type that uses a belt and a heating roller to secure a nip width, and is pressed against the fixing roller 601 through the fixing roller 601, the seamless belt 11, and the seamless belt 11. The pressure pad (pressure member) 12a, the pressure pad (pressure member) 12b, and the lubricant supply member 40 constitute main parts.

  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 is in contact with 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 includes 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 heat conduction is preferable so that heat is not easily taken from the seamless belt 11. A specific example of the belt member of the seamless belt is polyimide.

  The lubricant supply unit 40 includes a lubricant holding member 41 and a lubricant permeation restriction film 42. The lubricant holding member 41 has a large number of continuous pores, and examples thereof include felts and sponges. The lubricant holding member 41 is impregnated with a lubricant, and examples of the lubricant include silicon oil and fluorine oil.

  The lubricant permeation amount regulating film 42 has a large number of continuous pores, for example, a film obtained by stretching a fluororesin.

  Note that the peeling member 20 may be disposed on the downstream side of the nip portion of the fixing roller 601 as an auxiliary means for peeling. The peeling member 20 is held by the holder 20 b in a state where the peeling baffle 20 a is close to the fixing roller 601 in a direction (counter direction) opposite to the rotation direction of the fixing roller 601.

  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 the transfer material from being wound and has excellent image quality. 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.

  A heating roller 601 in which a halogen heater 14 as a heating member is provided includes a cylindrical metal pipe 171a having a thickness of about 5 to 20 mm using a metal member, for example, an aluminum material, and an outer periphery of the metal pipe 171a. It is formed as a hard roller having an outer diameter of about 50 to 80 mm, on which a PFA (perfluoroalkoxy) coating having a thickness of about 5 to 30 μm or a release layer 173a covering a PFA tube is formed. The heating roller 601 is independently driven by a heating roller drive motor Ma via a drive speed reduction system GKa.

  As the heating roller 17b, for example, an iron material is used as a base, a metal pipe 171b as a cylindrical metal core having a thickness of about 5 to 10 mm, and an outer peripheral surface of the metal pipe 171b is made of, for example, a silicon material and has a thickness of 3 A rubber roller layer 172b as an elastic body made of a soft rubber member having a thickness of ˜15 mm and a rubber hardness of 30 to 50 Hs (JIS, A rubber hardness), and a thickness of 15 to 100 μm on the surface of the rubber roll layer 172b A soft roller having an outer diameter of about 50 to 80 mm and having a PFA (perfluoroalkoxy) coating or a release layer 173b coated with a PFA tube is formed. The pressure roller 17b is also independently driven by the pressure roller drive motor Mb via the drive speed reduction system GKb.

  A fixing auxiliary roller 17c, which is a fixing auxiliary roller member having a halogen lamp HLa as a heating member therein, is provided on the outer periphery of the pressure roller 17b and upstream of the nip portion N between the heating roller 601 and the pressure roller 17b.

  The fixing auxiliary roller 17c includes a metal pipe 171c using, for example, an aluminum material as a base and a cylindrical metal core having a thickness of about 1 to 3 mm coated with PFA (perfluoroalkoxy), and a halogen lamp inside the metal pipe 171c. It is configured as a roller member in which HLa is disposed. The auxiliary fixing roller 17c is pressed against the pressure roller 17b by a spring (not shown), and is driven to rotate by the rotation of the pressure roller 17b.

  The toner image (or color toner image) on the recording paper P is fixed by the lower convex nip N formed between the heating roller 601 as a hard roller and the pressure roller 17b as a soft roller. .

  Further, a temperature sensor TS1 that is in contact with or not in contact with the heating roller 601 is provided to control the temperature of the heating roller 601. A temperature sensor TS2 that is in contact with or not in contact with the auxiliary fixing roller 17c is provided to control the temperature of the auxiliary fixing roller 17c.

  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 compound (1), (4), (6), (7), (8), (9) is obtained by subjecting a polycarboxylic acid and a long-chain aliphatic alcohol having 10 to 30 carbon atoms to dehydration condensation reaction. , (10), (13), (15) were produced.

  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 gave the above compound.

<Production of toner>
(Preparation of toner particles 1)
(1) Synthesis of low molecular weight latex: 1 liter of four-headed Kolben equipped with a stirrer, a cooling tube 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 and 66.7 g of compound (8) were added, the internal temperature was raised to 80 ° C., the mixture was stirred until the compound (8) 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 compound (8) 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 diameter 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 500 ml four-headed colben 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, , 0.12 g of tert-dodecyl mercaptan and 13.34 g of compound (8) were added, the internal temperature was raised to 80 ° C., and the mixture was stirred until the compound (8) was dissolved, and the temperature was maintained as it was. 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 compound (8) 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) Production of toner particles: Four-headed colben having 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. The pH was adjusted to 10 by adding 5N aqueous sodium hydroxide solution. 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 volume-based median diameter (D ₅₀ ) of the dispersed particles was measured using “Coulter Multisizer III” (manufactured by Beckman Coulter), and the particle diameter was 6.5 μm. Then, an aqueous solution in which 80.6 g of sodium chloride was dissolved in 700 ml of pure water 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 (toner particles) thus produced were filtered, washed by repeating resuspension in pure water and filtration, and then dried to obtain toner particles. This is referred to as “toner particle 1”. The median diameter and CV value of “toner particle 1” were measured under the above-mentioned conditions. The median diameter (D ₅₀ ) = 6.5 μm and the CV value = 18.2%.

(Preparation of toner particles 2)
“Toner particle 2” was prepared in the same manner except that 66.7 g of compound (8) used in preparation of toner particle 1 was changed to 100.0 g.

(Preparation of toner particles 3)
“Toner particle 3” was prepared in the same manner except that 66.7 g of compound (8) used in preparation of toner particle 1 was changed to 20.0 g.

(Preparation of toner particles 4)
“Toner particles 4” were produced in the same manner except that the compound (8) used in the production of the toner particles 1 was changed to the compound (10).

(Preparation of toner particles 5)
“Toner particles 5” were produced in the same manner except that the compound (8) used in the production of the toner particles 1 was changed to the compound (4).

(Preparation of toner particles 6)
“Toner particles 6” were prepared in the same manner except that the compound (8) used in the preparation of the toner particles 1 was changed to the compound (1).

(Preparation of toner particles 7)
“Toner particles 7” were prepared in the same manner except that the compound (8) used in the preparation of the toner particles 1 was changed to the compound (6).

(Preparation of toner particles 8)
“Toner particles 8” were prepared in the same manner except that the compound (8) used in the preparation of the toner particles 1 was changed to the compound (7).

(Preparation of toner particles 9)
“Toner particles 9” were prepared in the same manner except that the compound (8) used in the preparation of the toner particles 1 was changed to the compound (9).

(Preparation of toner particles 10)
“Toner particles 10” were prepared in the same manner except that the compound (8) used in the preparation of the toner particles 1 was changed to the compound (13).

(Preparation of toner particles 11)
“Toner particles 11” were prepared in the same manner except that the compound (8) used in the preparation of the toner particles 1 was changed to the compound (15).

(Preparation of toner particles 12)
“Toner particles 12” were prepared in the same manner except that the compound (8) used in the preparation of the toner particles 1 was changed to the comparative compound (1).

(Preparation of toner particles 13)
“Toner particles 7” were prepared in the same manner except that the compound (8) used in the preparation of the toner particles 1 was changed to the comparative compound (2).

(Preparation of toner particles 14)
“Toner particles 14” were prepared in the same manner except that the compound (8) used in the preparation of the toner particles 1 was changed to the comparative compound (3).

(Preparation of toner particles 15)
“Toner particles 15” were prepared in the same manner except that the compound (8) used in the preparation of the toner particles 1 was changed to carnauba wax.

(Preparation of toner particles 16)
“Toner particles 16” were prepared in the same manner except that the compound (8) used in the preparation of the toner particles 1 was changed to the comparative compound (4).

(Preparation of toner particles 17)
“Toner particles 17” were prepared in the same manner except that the compound (8) used in the preparation of the toner particles 1 was changed to the comparative compound (5).

(Preparation of toner particles 18)
“Toner particles 18” were prepared in the same manner except that the compound (8) used in the preparation of the toner particles 1 was changed to the comparative compound (6).

(Preparation of toner particles 19)
“Toner particles 19” were produced in the same manner except that the compound (8) used in the production of the toner particles 1 was changed to the comparative compound (7).

(Preparation of toner particles 20)
“Toner particles 20” were prepared in the same manner except that the compound (8) used in the preparation of the toner particles 1 was changed to the comparative compound (8).

Table 1 shows the ester compound having a specific structure used for the preparation of the toner particles, the amount thereof, the median diameter (D ₅₀ ) and CV value of the toner particles based on volume.

(External additive treatment of toner particles)
Subsequently, 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) are prepared in each of the “toner particles 1 to 20” prepared above. = 20 nm, hydrophobization degree = 63) was added in an amount of 1% by mass and mixed using a “Henschel mixer” (manufactured by Mitsui Miike Chemical Co., Ltd.). Thereafter, coarse particles were removed using a sieve having an opening of 45 μm to prepare “Toners 1 to 20”. These are designated as “Invention 1-11” and “Comparative Examples 1-9”.

<Preparation of developer>
Each of the “toners 1 to 20” produced above was mixed with a silicon carrier coated ferrite carrier having a median diameter (D ₅₀ ) of 60 μm on a volume basis so that the toner concentration was 6% by mass. 1-20 "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 transfer material surface temperature can be set as follows.

Fixing speed: can be set arbitrarily at 80 to 280 mm / sec (about 50 sheets / min). Surface temperature of transfer material: arbitrarily set at 90 to 240 ° C.

<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 range>
The surface temperature of the transfer material immediately after being discharged from the hot roll was changed in increments of 10 ° C. from 90 ° C. to 200 ° C. to produce a fixed image. As the transfer material, A4 size high-quality paper (65 g / m ² ) was used.

The fixable temperature range is determined based on the fixing strength of the obtained fixed image according to the method according to the mending tape peeling method described in Chapter 9 Section 1.4 of “Basics and Applications of Electrophotographic Technology: Electrophotographic Society”. Obtained using. 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 , “Scotch Mending Tape” (manufactured by Sumitomo 3M) Then, the image density before and after peeling was measured, and the residual ratio of the image density was determined as the fixing rate.

  The fixing temperature at which a fixing ratio of 90% or more was obtained was evaluated as a fixing temperature, and the fixing temperature range was evaluated as a fixing temperature range. For the measurement of the image density, a reflection densitometer “RD-918” (manufactured by Macbeth) was used.

Evaluation Criteria A: When the fixable temperature range is 100 ° C. or higher, the fixable temperature range is wide and excellent ○: When the fixable temperature range is 70 ° C. or higher, the fixable temperature range is wide and good Δ: The fixable temperature range is 40 When the temperature is higher than or equal to ° C., the fixable temperature range is narrowed, but there is no practical problem.

<Evaluation of fixing offset>
Fixing offset is 1000 sheets of continuous printing on high quality paper (65 g / m ² ) of A3 size conditioned in a low temperature and low humidity environment of 10 ° C and 20% RH. The image and the surface of the hot roll were directly visually observed, and the print image and the degree of offset due to toner adhesion generated on the surface of the hot roll were evaluated.

Evaluation criteria A: Good with no occurrence of offset on the image and on the surface of the heat roll ○: Not seen on the image, but the heat roll has an offset, but there is no practical problem ×: Due to the offset on the image Dirt is generated.

<Evaluation of fixing strength>
The fixing strength was evaluated by a tape peeling test.

  A solid image having an initial density of 1.0 to 1.2 was printed at a fixing speed of 80 mm / sec and a surface temperature of the transfer material of 100 ° C. After pasting “mending tape” (manufactured by Sumitomo 3M) on this solid image, the image density of the peeled portion was measured, the ratio with the initial image density was calculated, and the fixing strength by the tape peeling method was evaluated. . For the measurement of the image density, a reflection densitometer “RD-918” (manufactured by Macbeth) was used.

Tape peeling method (1) Measure absolute reflection density D0 of solid black of 5 mm square (2) Lightly affix "Mending tape" (manufactured by Sumitomo 3M: No.810-3-12) (3) 1 kPa (4) The tape is peeled off with an angle of 180 ° and a force of 200 g. (5) The absolute reflection density D ₁ after peeling is measured. (6) Fixing strength = 100 × D ₁ / D ₀ (%)
Evaluation Criteria A: Fixing strength is 95% or more, good ○: Fixing strength is 90% or more, no practical problem ×: Fixing strength is less than 90%.

《Image evaluation》
The fixing speed is 280 mm / sec, the surface temperature of the transfer material is set to 150 ° C. so that the surface temperature of the transfer material is 100 ° C., and A3 size high quality paper (65 g / m ² ) is used, and 500,000 sheets are intermittently used. After copying, the image density and fogging printed on the first sheet and the 100th sheet after standing for a day and night 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 0.0). The measurement was performed using a Macbeth reflection densitometer “RD-918” (manufactured by Macbeth Co., Ltd.).

Evaluation criteria ◎: The black density of both the first and the 100th sheets is better than 1.2. ○: The solid black density of the first sheet is 1.2 to 0.8, which is a little light but practically satisfactory. X: The black density of both the first sheet and the 100th sheet is less than 0.8.

<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 Co., Ltd.).

Evaluation Criteria A: The relative density of both the first and the 100th sheets is less than 0.002 and there is no problem of fogging. ○ The relative density of the first sheet is 0.002 to 0.005, and the relative density of the 100th sheet is Slight fogging is recognized at 0.002 or less, but there is no practical problem. X: The relative density of both the first and 100th sheets exceeds 0.005, and the fogging is severe.

  The evaluation results are shown in Table 2.

  As can be seen from Table 2, all of the evaluation items of the “present inventions 1 to 11” are excellent, but the “comparative examples 1 to 9” outside the present invention have some problems in the evaluation items. .

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

Explanation of symbols

1 Semiconductor Laser Light Source 2 Polygon Mirror 3 fθ Lens 3
4 Photosensitive drum 5 Charging device 6 Developing device 7 Transfer device 9 Separator (separation electrode)
P transfer material 10 fixing device 11 cleaning device 12 pre-charge exposure (PCL)
13 Cleaning blade

Claims (1)

In the electrostatic image developing toner having at least a binder resin and a colorant, the following general formula (1)
A toner for developing an electrostatic image, comprising a compound represented by the formula:
However, said if an electrostatic image developing toner contains plural kinds of ester compounds represented by the following general formula (1), or an ester compound, wherein the toner for developing electrostatic images is represented by the following general formula (1) The case where the ester compound represented by the general formula (X) and / or the general formula (Y) is contained is excluded.
(In the general formula (1), X is H or _{-CO-R 4,} R 4 is an alkyl group having 1 to 4 carbon _{atoms, R} 1 ~
R ₃ represents an alkyl group having 10 to 30 carbon atoms. )
(In the general formula _{(X), R 1, R} 2 and _{R 3} charcoal represents an alkyl group which may have a substituent group having 10 to 30 carbon atoms.)
(In general formula (Y), R ₄ and R ₅ represent an alkyl group which may have a substituent having 10 to 30 carbon atoms.)