JP2007114648A - Electrophotographic toner and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic toner which ensures a wide anti-offset region and gives a high quality toner image, having a high gloss and free of uneven gloss and white streaks as image defects, even when a toner image is fixed on a transfer material at low temperature. <P>SOLUTION: The electrophotographic toner contains a resin and a colorant, wherein the electrophotographic toner contains liquid paraffin and has a weight average molecular weight, in a gel permeation chromatograph of 5,000-50,000. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electrophotographic toner and an image forming method using the electrophotographic toner.

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

  In order to obtain a high gloss image by a conventional method, it is necessary to uniformly form a release agent layer on the surface of the toner image. The fixing temperature is increased, the fixing speed is reduced, or the transparent toner layer is formed on the toner image. Technical measures such as further forming are taken.

  On the other hand, in order to reduce power consumption and high-speed printing, the energy of fixing devices has been reduced (low-temperature fixing) in recent years. It was difficult to achieve both high gloss and low energy.

  In addition, if low temperature fixing is attempted, the softening point and glass transition temperature of the binder resin will be kept low, and the toner on the blade, toner transport roller, heating roller, etc. that regulates the toner layer on the developing roller during continuous printing will be reduced. It caused fusion and caused image defects.

In order to solve this, studies have been made to try to improve the image quality by incorporating silicon oil having a low surface tension into the toner (see, for example, Patent Document 1).
JP 2004-295074 A

  However, the above proposal (contains a silicone oil having a low surface tension in the toner) has not led to the resolution of white streaks and gloss unevenness that are image defects.

  The present invention has been made in view of the above problems, and even when a toner image is fixed to a transfer material at a low temperature, the non-offset region is wide, has high gloss, and there is no gloss unevenness or white streak that causes an image defect. An object of the present invention is to provide an electrophotographic toner capable of obtaining high quality toner image quality and an image forming method using the electrophotographic toner.

  The present invention is achieved by adopting the following configuration.

1.
In an electrophotographic toner containing a binder resin and a colorant,
The electrophotographic toner comprises liquid paraffin;
An electrophotographic toner having a weight average molecular weight of 5,000 to 50,000 in a gel permeation chromatograph of the electrophotographic toner.

2.
In an electrophotographic toner containing a binder resin and a colorant,
The electrophotographic toner contains liquid paraffin and a releasing agent having a melting point of 50 to 100 ° C.
2. The electrophotographic toner according to 1 above, wherein the electrophotographic toner has a polymerization average molecular weight of 5,000 to 50,000 in a gel permeation chromatograph.

3.
3. The electrophotographic toner according to 1 or 2 above, wherein a peak top molecular weight of the liquid paraffin in a gel permeation chromatograph is 200 to 600.

4).
4. The electrophotographic toner according to any one of 1 to 3 above, wherein the electrophotographic toner has a glass transition temperature (Tg) of 20 to 45 ° C.

5.
5. The electron according to any one of 1 to 4, wherein the electrophotographic toner has a core-shell structure in which a shell is provided on a surface of a core particle, and the core particle includes the liquid paraffin. Toner for photography.

6).
6. The electrophotographic toner according to any one of 1 to 5, wherein the electrophotographic toner is produced by an emulsion association method.

7).
The toner for electrophotography is obtained by adding a small particle size external additive having a number average primary particle size of 10 to 60 nm and a large particle size external additive having a number average primary particle size of 80 nm to 1 μm as external additives. 7. The electrophotographic toner according to any one of 1 to 6, wherein the toner is for electrophotography.

8).
8. An image forming method comprising the step of forming a toner image by using the electrophotographic toner according to any one of 1 to 7 above and developing the image on a transfer material in multiple colors.

  The electrophotographic toner of the present invention and the image forming method using the electrophotographic toner have a wide non-offset area, high gloss, and no gloss unevenness or white streaks that cause image defects even when fixed at low temperatures. And an excellent effect of obtaining a high-quality toner image.

  As a means for solving the above problems, the present inventors have studied to contain a liquid compound that does not require heat of fusion in the toner.

  The reason for this is that the liquid compound that does not require the heat of fusion maintains a liquid state even when the fixing temperature is lowered, so that a uniform layer can be formed on the toner image. This is because it can be made uniform and uneven gloss can be suppressed.

  However, when silicon oil is contained in the toner as a liquid compound, silicon dioxide derived from silicon contained in the silicon oil adheres to the charging wire in the image forming apparatus as dirt and is discharged during corona discharge. Defects occur and white streaks appear on the image, which is a problem.

  By including liquid paraffin in the toner, the present inventors have exhibited a low-temperature fixing performance, have a wide non-offset area, high gloss, high-quality without uneven gloss and white streaks that cause image defects. It was found that a toner image can be formed.

  It was also found that the toner has a plasticizer effect that lowers the glass transition temperature.

  Hereinafter, the present invention will be described in detail.

<Liquid paraffin>
The toner of the present invention is characterized by containing liquid paraffin in the toner.

  The liquid paraffin as used in the present invention is a hydrocarbon compound having no endothermic peak in differential scanning calorimetry (DSC) measurement.

Preferred physical properties of liquid paraffin include hydrocarbon compounds having a kinematic viscosity of 4 to 200 mm ² / s at 40 ° C. or a peak top molecular weight of 200 to 600 in gel permeation chromatography (hereinafter abbreviated as GPC) measurement. It is. Particularly preferably, the peak top molecular weight in GPC measurement is 240 to 550.

  The kinematic viscosity at 40 ° C. is measured with a “B-type viscometer” (manufactured by Tokimec Co., Ltd.) in accordance with JIS K2283.

  The molecular weight of liquid paraffin by GPC is measured by the following measurement method.

  Liquid paraffin is stirred and dissolved in tetrahydrofuran at 40 ° C. until the dissolution is visually confirmed to prepare a measurement sample solution.

  The measurement is performed by injecting a measurement sample solution into the GPC. The measurement conditions for GPC are shown below.

Apparatus: HLC-8220 (manufactured by Tosoh Corporation)
Column: TSKgel G2000HXL (inner diameter 7.8 mm × 30 cm) triple (manufactured by Tosoh Corporation)
Column temperature: 40 ° C
Solvent: Tetrahydrofuran Flow rate: 1.0 ml / min
Measurement sample concentration: 0.1% (V / W)
Sample injection: 100 μl
Detector: Refractive index detector (RI detector)
Calibration curve: standard polystyrene, n-hexylbenzene.

  Specific examples of liquid paraffin include P-40, P-55, P-60, P-70, P-80, P-85, P-100, P-120, and P-150 manufactured by Matsumura Oil Research Institute. , P-200, P-230, P-260, P-300, P-350, P-350P, P-500, and the like.

  The amount of liquid paraffin added is preferably 0.5 to 20% by mass relative to the total amount of toner. In this addition amount range, good results can be obtained for uneven gloss.

<Weight average molecular weight of toner>
The weight average molecular weight of the soluble component in GPC of the toner of the present invention is 5000 to 50000, preferably 15000 to 30000, and more preferably 20000 to 30000. In addition, what does not have an insoluble component of resin is preferable.

  The measurement of the molecular weight of the toner by GPC is performed by the following measurement method.

  A toner sample to be measured is dissolved in tetrahydrofuran to a concentration of 1 mg / ml to prepare a measurement sample solution. The dissolution is performed at room temperature using an ultrasonic disperser for 5 minutes, and then filtered through a membrane filter having a pore size of 0.2 μm. The measurement is performed by injecting 10 μl of a measurement sample solution into GPC. The measurement conditions for GPC are shown below.

Apparatus: HLC-8220 (manufactured by Tosoh Corporation)
Column: TSKguardcolumn + TSKgelSuperHZM-M3 series (manufactured by Tosoh Corporation)
Column temperature: 40 ° C
Solvent: Tetrahydrofuran Flow rate: 0.2 ml / min
Detector: Refractive index detector (RI detector)
In the sample molecular weight measurement apparatus, the molecular weight distribution having the sample is calculated using a calibration curve measured using monodisperse polystyrene standard particles. Ten polystyrenes were used for calibration curve measurement.

<< Glass Transition Temperature Tg of Toner >>
The glass transition temperature of the toner of the present invention is preferably 20 to 45 ° C, more preferably 25 to 40 ° C.

  The glass transition temperature of the toner of the present invention can be measured using “DSC-7 differential scanning calorimeter” (manufactured by PerkinElmer) or “TAC7 / DX thermal analyzer controller” (manufactured by PerkinElmer).

  As a measurement procedure, toner 4.5 mg to 5.0 mg is precisely weighed to 2 digits after the decimal point, sealed in an aluminum pan (KIT No. 0219-0041), and set in a DSC-7 sample holder. The reference used an empty aluminum pan. The measurement conditions were a measurement temperature of 0 ° C. to 200 ° C., a temperature increase rate of 10 ° C./min, a temperature decrease rate of 10 ° C./min, and heat-cool-heat temperature control. Analysis was performed based on the data in Heat.

  The glass transition temperature is obtained by drawing an extension line of the baseline before the rise of the first endothermic peak and a tangent line indicating the maximum slope between the rise portion of the first peak and the peak vertex, and using the intersection as the glass transition temperature. Show.

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

  The toner of the present invention preferably has a core / shell structure in which a shell is provided on the surface of the core particles. The core particles preferably contain the liquid paraffin.

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

  Then, an external additive is added to the formed shell surface to produce the toner of the present invention having a core / shell structure.

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

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

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

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

  The core particles constituting the toner of the present invention are produced by a production method in which resin fine particles and colorant particles are aggregated and fused. The shape of the core particles is controlled, for example, by controlling the heating temperature in the aggregation / fusion process and the heating temperature and time in the first aging process. That is, by controlling the heating temperature to be lower in the aggregation / fusion process, the progress of the fusion between the resin particles is suppressed and the modification is promoted. Further, it is possible to control the irregular shape of the core particle by lowering the heating temperature and shortening the time in the first ripening step.

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

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

  For example, the core particles constituting the toner of the present invention are obtained by dissolving or dispersing a release agent component in a polymerizable monomer forming the resin (A), and then mechanically dispersing fine particles in an aqueous medium. A method in which the composite resin fine particles formed through the step of polymerizing the polymerizable monomer by emulsion polymerization and the colorant particles are salted out / fused is preferably used. When the release agent component is dissolved in the polymerizable monomer, the release agent component may be dissolved or melted or dissolved.

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

[Dissolution / dispersion process]
This step is a step of preparing a radical polymerizable monomer solution in which a release agent compound is dissolved in a radical polymerizable monomer and the release agent compound is mixed. It is preferable to add liquid paraffin during this step.

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

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

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

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

  The colorant fine particles can be prepared by dispersing the colorant in an aqueous medium. The dispersion treatment of the colorant is performed in a state where the surfactant concentration is set to a critical micelle concentration (CMC) or more in water. The disperser used for the dispersion treatment of the colorant is not particularly limited, but preferably an ultrasonic disperser, a mechanical homogenizer, a pressure disperser such as a manton gorin or a pressure homogenizer, a sand grinder, a Getzmann mill, a diamond fine mill, or the like. Examples thereof include a medium type disperser. Moreover, as a surfactant used, the same thing as the above-mentioned surfactant can be mentioned. The colorant (fine particles) may be surface-modified. In the surface modification method of the colorant, the colorant is dispersed in a solvent, the surface modifier is added to the molecular weight solution, and the system is reacted by raising the temperature. After completion of the reaction, the colorant is 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 / fusing method, which is a preferred agglomeration and fusing method, is a salting out method comprising an alkali metal salt, an alkaline earth metal salt, a trivalent salt, or the like in water in which resin fine particles and colorant fine particles are present. An agent is added as an aggregating agent having a critical agglomeration concentration or higher, and then salting-out proceeds by heating to a temperature not lower than the glass transition temperature of the resin fine particles and not lower than the melting peak temperature (° C.) of the mixture. At the same time, it is a process of fusing. Here, the alkali metal salt and alkaline earth metal salt which are salting-out agents include lithium, potassium, sodium and the like as the alkali metal, and examples of the alkaline earth metal include magnesium, calcium, strontium and barium. Preferably, potassium, sodium, magnesium, calcium, and barium are used.

  When agglomeration and fusion are performed by salting out / fusion, 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.

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

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

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

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

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

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

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

[Drying process]
In this step, the washed toner cake is dried to obtain dried toner particles. Examples of dryers used in this process include spray dryers, vacuum freeze dryers, vacuum dryers, etc., stationary shelf dryers, mobile shelf dryers, fluidized bed dryers, rotary dryers It is preferable to use a stirring dryer or the like. The moisture of the dried toner particles is preferably 5% by mass or less, more preferably 2% by mass or less. In addition, when the toner particles subjected to the drying treatment are aggregated 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 average particle size of the toner of the present invention is preferably 3 to 9 μm in terms of median particle size (D ₅₀ ) on a volume basis. The volume-based median particle size (D ₅₀ ) is measured and calculated using a device in which a computer system for data processing (Beckman Coulter, Inc.) is connected to “Coulter Multisizer III” (Beckman Coulter, Inc.). can do.

  As a measurement procedure, 0.02 g of toner is blended with 20 ml of a surfactant solution (for example, a surfactant solution obtained by diluting a neutral detergent containing a surfactant component 10 times with pure water for the purpose of dispersing the toner). After that, ultrasonic dispersion is performed for 1 minute to prepare a toner dispersion. This toner dispersion is injected into a beaker containing ISOTON II (manufactured by Beckman Coulter, Inc.) in a sample stand with a pipette until a measurement concentration of 5 to 10% is reached, 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 Isobutyl acid, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, phenyl acrylate, etc., acrylate derivatives, 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 74, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. And CI Pigment Yellow 138.

  Examples of the colorant for green or cyan include C.I. I. Pigment blue 15, C.I. I. Pigment blue 15; 2, C.I. I. Pigment blue 15; 3, C.I. I. Pigment blue 15; 4, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. Pigment blue 62, C.I. I. Pigment blue 66, C.I. I. And CI Pigment Green 7.

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

(Release agent)
Examples of the mold release agent used in the present invention include polyethylene wax, paraffin wax, microcrystalline wax, Fischer-Tropsch wax, dialkyl ketone wax such as distearyl ketone, carnauba wax, montan wax, trimethylolpropane tri Behenate, pentaerythritol tetramyristate, pentaerythritol tetrastearate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18-octadecanediol distearate, tri Ester waxes such as meristate tristearyl and distearyl maleate, ethylene diamine dibehenyl amide, and trimellitic acid tristearyl amide Such as system wax, and the like.

  Especially, as a mold release agent melting | fusing point, a thing whose melting | fusing point is 50-100 degreeC is preferable.

  The addition amount of the release agent is preferably 1 to 15% by mass and more preferably 3 to 12% by mass with respect to the whole toner.

  This is because the addition of 1 to 15% by mass of a release agent having a melting point of 50 to 100 ° C. improves the offset property at a low fixing temperature and increases the degree of gloss unevenness.

The release agent melting point of the toner can be measured using “DSC-7 differential scanning calorimeter” (manufactured by PerkinElmer) or “TAC7 / DX thermal analyzer controller” (manufactured by PerkinElmer).
As a measurement procedure, 4.5 to 5.0 mg of toner is precisely weighed to two digits after the decimal point, sealed in an aluminum pan (KIT No. 0219-0041), and set in a DSC-7 sample holder. The reference used an empty aluminum pan. The measurement conditions were a measurement temperature of 0 ° C. to 200 ° C., a temperature increase rate of 10 ° C./min, a temperature decrease rate of 10 ° C./min, and heat-cool-heat temperature control. Analysis was performed based on the data in Heat, and the peak top temperature of the release agent endothermic peak was defined as the release agent melting point.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  FIG. 1 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 heating roller 41 and the pressure roller 42 cause the transfer material P to be transported. 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 in contact with the heating roller 71. In FIG. 2, reference numeral 17 denotes a toner image formed on a transfer material (transfer paper) P.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  4 is a type using a soft roller and a heating roller that secures a fixing nip and prevents the transfer material from being wound and has excellent image quality. The heating roller 601 as a heating roller member, A soft roller 17 b as a roller member is used, and a halogen lamp 14 as a heating member is provided inside the heating roller 601.

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

  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 liquid paraffin>
“Liquid paraffin 1 to 7” shown in Table 1 was prepared.

<Production of toner>
<Preparation of Toner Bk1>
(Manufacture of core resin particle A) Production of three-layer structure resin particle First-stage polymerization 4 g of polyoxyethylene (2) sodium dodecyl ether sulfate in a reaction vessel equipped with a stirrer, temperature sensor, cooling pipe, and nitrogen introducing device And 3000 g of ion-exchanged water were added, and the internal temperature was raised to 80 ° C. while stirring at a stirring speed of 230 rpm under a nitrogen stream. After heating, 10 g of potassium persulfate dissolved in 400 g of ion-exchanged water was added to obtain a liquid temperature of 75 ° C., the following monomer mixture was added dropwise over 1 hour, and then heated at 75 ° C. for 2 hours. Polymerization was carried out by stirring to obtain “resin particles (A1)”.

Styrene 532g
200g of n-butyl acrylate
Methacrylic acid 68g
n-Octyl mercaptan 16g
Second stage polymerization A reaction vessel equipped with a stirrer, a temperature sensor, a condenser, and a nitrogen inlet is charged with a solution of 3 g of polyoxyethylene (2) sodium dodecyl ether sulfate in 1560 g of ion-exchanged water and heated to 80 ° C. After heating, 35 g of the above-mentioned “resin particles (A1)”, a solution in which paraffin wax as a release agent and liquid paraffin 1 are dissolved at 80 ° C. are added, and a mechanical disperser having a circulation path A dispersion containing emulsified particles (oil droplets) was prepared by mixing and dispersing for 1 hour using “CLEAMIX” (M Technique Co., Ltd.).

Styrene 100g
62 g of n-butyl acrylate
Methacrylic acid 12g
n-octyl mercaptan 1.75 g
Paraffin wax (melting point 75 ° C) 35g
Liquid paraffin 1 28g
Next, an initiator solution in which 5 g of potassium persulfate was dissolved in 100 g of ion-exchanged water was added to this dispersion, and the system was heated and stirred at 80 ° C. for 1 hour to conduct polymerization, and “resin particles ( A2) "was obtained.

Third stage polymerization Furthermore, a solution prepared by dissolving 5.45 g of potassium persulfate in 220 g of ion-exchanged water was added, and under a temperature condition of 80 ° C.,
294 g of styrene
155 g of n-butyl acrylate
n-octyl mercaptan 7.08 g
A monomer mixture consisting of was added dropwise over 1 hour. After completion of the dropwise addition, polymerization was carried out by heating and stirring for 2 hours, followed by cooling to 28 ° C. to obtain “resin particles (A3)”. This is designated as “resin particle A”.

(Manufacture of resin particle B for shell)
In a reaction vessel equipped with a stirrer, a temperature sensor, a condenser, and a nitrogen introduction device, 4 g of sodium polyoxyethylene (2) dodecyl ether sulfate and 3000 g of ion-exchanged water were charged, while stirring at a stirring speed of 230 rpm under a nitrogen stream, The internal temperature was raised to 80 ° C. After heating, 10 g of potassium persulfate dissolved in 400 g of ion-exchanged water was added to obtain a liquid temperature of 80 ° C. The following monomer mixture was added dropwise over 2 hours and then heated at 80 ° C. for 2 hours. Polymerization was performed by stirring to obtain resin particles. This is designated as “resin particle B”.

624 g of styrene
120g 2-ethylhexyl acrylate
Methacrylic acid 56g
16.4 g of n-octyl mercaptan
(Preparation of colorant Bk dispersion)
90 g of sodium dodecyl sulfate was dissolved in 1600 g of ion-exchanged water with stirring. While stirring this solution, 420 g of carbon black “Regal 330R” (manufactured by Cabot Corp.) is gradually added, and then dispersed by using a stirrer “Claremix” (manufactured by M Technique Co., Ltd.). A dispersion of agent particles was prepared. This is referred to as “colorant Bk dispersion”. The particle diameter of the colorant particles in this colorant Bk dispersion was measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.) and found to be 110 nm.

(Aggregation / fusion process)
In a reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introduction device, 392 g of “resin particles A”, 1100 g of ion-exchanged water, and 200 g of “colorant Bk dispersion” are charged in liquid. After adjusting the temperature to 30 ° C., 5N aqueous sodium hydroxide solution was added to adjust the pH to 10. Next, an aqueous solution in which 60 g of magnesium chloride was dissolved in 60 g of ion-exchanged water was added over 10 minutes at 30 ° C. with stirring. After holding for 3 minutes, the temperature was raised and the system was heated to 80 ° C. over 60 minutes, and the particle growth reaction was continued while maintaining 80 ° C. In this state, the particle size of the associated particles was measured with “Coulter Multisizer III” (manufactured by Beckman Coulter). When the median diameter on the volume basis reached 6 μm, 40 g of sodium chloride was changed to 160 g of ion-exchanged water. The dissolved aqueous solution was added to stop particle growth, and as a ripening step, fusion between the particles was advanced by heating and stirring at a liquid temperature of 80 ° C. for 1 hour to form “core particles 1”.

(Shelling process)
Next, 44 g of “resin particle B” is added in terms of solid content, and stirring is continued at 80 ° C. for 1 hour to fuse the particles of “resin particle B” to the surface of “core particle 1” to form a shell. I let you. Here, an aqueous solution dissolved in 150 g of sodium chloride and 600 g of ion-exchanged water was added to carry out an aging treatment, and the mixture was cooled to 30 ° C. when the desired circularity was reached.

(Washing / drying process)
The formed particles were subjected to solid-liquid separation with a basket-type centrifuge “MARkIII model number 60 × 40” (manufactured by Matsumoto Kikai) to form a wet cake of toner base particles. The wet cake was washed with ion exchange water at 40 ° C. until the electric conductivity of the filtrate reached 5 μS / cm by the basket type centrifuge, and then transferred to “flash jet dryer” (manufactured by Seishin Enterprise Co., Ltd.). The toner was dried until the amount became 0.5% by mass to prepare “toner base particles”.

(Abduction agent addition process)
In the “toner base particles” obtained above, 1% by mass of hydrophobic silica particles (number average primary particle size = 12 nm) as a small particle size external additive and titanium doped silica particles (several as a large particle size external additive) 0.3% by mass (average primary particle size = 120 nm) was added and mixed with a Henschel mixer to prepare “Toner Bk1”.

  Toner Bk1 had a liquid paraffin content of 4% by mass and a paraffin wax content of 5% by mass.

<Production of toners Bk2, Bk3>
“Toners Bk2 and Bk3” were prepared in the same manner as in the preparation of the toner Bk1, except that the type and amount of liquid paraffin were changed as shown in Table 2.

<Preparation of Toner Bk4>
In the preparation of the toner Bk2, the amount of the polymerization initiator for the first stage polymerization is 15 g, the amount of the n-octyl mercaptan is 30 g, the amount of the polymerization initiator for the second stage polymerization is 10 g, the amount of the n-octyl mercaptan is 10 g, The amount of the polymerization initiator for step polymerization is 8 g, the amount of n-octyl mercaptan is 20 g, and the amount of the polymerization initiator is 10 g, the amount of n-octyl mercaptan is 30 g, and the external additives are large particles. “Toner Bk4” was prepared in the same manner except that the diameter particles were changed to polymethyl methacrylate particles.

<Preparation of Toner Bk5>
In the preparation of the toner Bk2, except that the second-stage polymerization n-octyl mercaptan was changed to 5 g, the third-stage polymerization n-octyl mercaptan was changed to 18 g, and the large particle size particles of the external additive were changed to polymethyl methacrylate particles. Made “Toner Bk5” in the same manner.

<Preparation of Toner Bk6>
In the preparation example of toner Bk2, the polymerization initiator amount for the second stage polymerization is 5.5 g, the n-octyl mercaptan is 1 g, the polymerization initiator amount for the third stage polymerization is 5 g, and the n-octyl mercaptan is 3 g. “Toner Bk6” was prepared in the same manner except that the large particle size particles of the external additive were changed to polymethyl methacrylate particles.

<Preparation of Toner Bk7>
In the preparation example of toner Bk1, the first-stage polymerization styrene was changed to 448 g, n-butyl acrylate 328 g, and methacrylic acid 24 g. Second-stage polymerization styrene 94 g, n-butyl acrylate 75 g, and methacrylic acid In the production example of the resin particle B for the shell, styrene is 520 g, n-butyl in the example of changing to 5.2 g, changing the styrene of the third stage polymerization to 242 g, n-butyl acrylate is 193 g, and methacrylic acid is 13.5 g. In addition to changing acrylate to 216g and methacrylic acid to 64g, change the addition amount of liquid paraffin and release agent as shown in Table 1, and change the large particle size of external additive to polymethyl methacrylate particle “Toner Bk7” was prepared in the same manner except that.

<Preparation of Toner Bk8>
In the preparation example of the toner Bk1, the first-stage polymerization styrene was changed to 448 g, n-butyl acrylate 328 g, and methacrylic acid 24 g, the second-stage polymerization styrene 97 g, n-butyl acrylate 71 g, and methacrylic acid Changed to 5.2 g, 251 g of third-stage polymerization styrene, 184 g of n-butyl acrylate, 13.5 g of methacrylic acid, and 520 g of styrene, n-butyl in the production example of resin particle B for shell The acrylate was changed to 216 g and the methacrylic acid was changed to 64 g, and the addition amount of the liquid paraffin and the release agent were changed as shown in Table 1, and the large particle size particles of the external additive were changed to zinc stearate particles. Other than that, “Toner Bk8” was produced in the same manner.

<Preparation of Toner Bk9>
In the preparation example of the toner Bk1, the first-stage polymerization styrene was changed to 536 g, the n-butyl acrylate was changed to 200 g, the methacrylic acid was changed to 64 g, the second-stage polymerization styrene was 117 g, the n-butyl acrylate was 43.5 g, The acid was changed to 14 g, the third-stage polymerization styrene was changed to 301 g, the n-butyl acrylate was changed to 112 g, and the methacrylic acid was changed to 36 g. 184g, methacrylic acid was changed to 56g, the addition amount of liquid paraffin and the addition amount of the release agent were changed as shown in Table 1, except that the large particle size particles of the external additive were changed to zinc stearate particles Similarly, “Toner Bk9” was produced.

<Preparation of Toner Bk10>
In the preparation example of toner Bk1, the first-stage polymerization styrene was changed to 560 g, n-butyl acrylate was changed to 176 g, and methacrylic acid was changed to 64 g, the second-stage polymerization styrene was changed to 122 g, n-butyl acrylate was changed to 38 g, and methacrylic acid was changed. 14g, 314g of styrene in the third stage polymerization, 99g of n-butyl acrylate, and 36g of methacrylic acid were changed to 560g of styrene and 160g of n-butyl acrylate in the production example of the resin particle B for shell. Same as that except that methacrylic acid was changed to 80 g, the addition amount of liquid paraffin was changed as shown in Table 1, the release agent was not added, and the large particle size particles of the external additive were changed to zinc stearate particles Thus, “Toner Bk10” was produced.

<Preparation of Toner Bk11>
In the production example of the toner Bk1, the liquid paraffin at the second stage polymerization was not added, the addition amount of paraffin wax was changed, and the large particle size particles of the external additive were changed to zinc stearate particles. Toner Bk11 "was produced.

<Preparation of Toner Bk12>
In the production example of the toner Bk1, liquid paraffin and paraffin wax at the second stage polymerization were not added, silicon oil was added as a release agent, and the large particle size particles of the external additive were changed to zinc stearate particles. Similarly, “Toner Bk12” was produced.

<Preparation of Toner Bk13>
“Toner Bk13” was prepared in the same manner as in the production example of toner Bk4, except that n-octyl mercaptan in the second stage polymerization was changed to 15 g, and the large particle size particles of the external additive were changed to zinc stearate particles. .

<Preparation of Toner Bk14>
In the production example of toner Bk6, the polymerization initiator at the second stage polymerization was changed to 5 g, the polymerization initiator at the third stage polymerization was changed to 4.5 g, and the large particle size particles of the external additive were changed to zinc stearate particles. “Toner Bk14” was produced in the same manner except for the change.

<Preparation of Toners C1 to C14>
The same procedure was performed except that 420 g of “Regal 330R” (manufactured by Cabot Corporation) used in the preparation of the colorant Bk dispersion of “Toners Bk1 to Bk14” was changed to 210 g of “CI Pigment Blue 15: 3”. “Toners C1 to C14” were produced.

<Preparation of Toners M1 to M14>
“Toner Bk1 to Bk14” was similarly used except that 420 g of “Regal 330R” (manufactured by Cabot Corporation) used in the preparation of the colorant Bk dispersion was changed to 357 g of “CI Pigment Red 122”. M1-M14 "were produced.

<Preparation of Toners Y1 to Y14>
“Toner Bk1 to Bk14” was similarly used except that 420 g of “Regal 330R” (manufactured by Cabot Corporation) used in the preparation of the colorant Bk dispersion was changed to 378 g of “CI Pigment Yellow 74”. Y1-Y14 "were produced.

  Table 2 shows the compounds used in the production of “Toners Bk1 to Bk14” and their amounts, the molecular weight of the toner, and the glass transition temperature (Tg) of the toner.

  The measurement results of “toners C1 to C14”, “toners M1 to M14”, and “toners Y1 to Y14” are the same as the measurement results of “toners Bk1 to Bk14”, and therefore will be omitted.

<Production of developer>
“Developer Bk1 to Bk14” and “Developer C1 to C14” having a toner concentration of 6% by mass are mixed with each of the toner particles produced above with a ferrite carrier coated with a silicone resin and having a volume average particle diameter of 60 μm. “Developers M1 to M14” and “Developers Y1 to Y14” were prepared.

《Image evaluation》
As the toner image evaluation apparatus produced above, a “bizhub PRO C500” (manufactured by Konica Minolta Business Technologies) equipped with the fixing device of FIG. 2 was used.

  The fixing speed and the surface material of the heating roller were as follows.

Fixing speed: 230mm / sec
Heat roller surface material: PTFE
Heating roller surface temperature: 125 ° C (Note that the low-temperature fixing test is changed as appropriate)
The image evaluation was performed on the following items in an environment of 20 ° C. and 55% RH in which the toner and the developer prepared above were sequentially loaded in the image evaluation apparatus.

The print is an image with a pixel ratio of 10% (original image with character image 7%, human face photo, solid white image, solid black image divided into 1/4 each) A4 quality fine paper (64 g / m ²⁾ ) The white streak evaluation was performed on an image after 50,000 copies.

(Low temperature fixability)
Low-temperature fixability is achieved by changing the surface temperature of the heating roller of the image evaluation apparatus (measured at the center of the roller) in increments of 5 ° C. within the range of 90 to 130 ° C., and with respect to the transport direction at each surface temperature. After the A4 image having a solid black belt image having a width of 5 mm in the vertical direction is conveyed and fixed by vertical feeding, the A4 image having a solid black belt image having a width of 5 mm and a halftone image having a width of 20 mm is perpendicular to the conveyance direction. Judgment was performed based on a temperature region (non-offset region) in which the image is not smudged due to the fixing offset when transported in the lateral direction.

Evaluation criteria A: The lower limit temperature of the non-offset region is 110 ° C. or lower, and the temperature region is 15 ° C. or higher. ○: The lower limit temperature of the non-offset region is 120 ° C. or lower, and the temperature region is lower than 15 ° C. The lower limit temperature of the region is 125 ° C or higher.

(Glossiness)
The glossiness is represented by a value obtained by measuring the glossiness of a solid image portion by a gloss meter “VGS-1D” (manufactured by Nippon Denshoku Industries Co., Ltd.) at an incident angle of 75 ° according to JIS-Z8741-1983 method 2. It is.

Evaluation criteria A: High gloss area where the gloss of the solid image part is 27 or more B: Semi-gloss area where the gloss of the solid image part is less than 17 to 27 x: Low gloss where the gloss of the solid image part is less than 17 region.

(Glossiness unevenness)
The unevenness of the glossiness was evaluated by visually observing the gloss of the solid image portion with a magnifier.

Evaluation Criteria A: Uneven gloss cannot be detected. O: Uneven gloss cannot be detected unless magnified with a loupe. X: Uneven gloss can be visually detected.

(White lines)
As for white stripes, solid black images were visually evaluated.

Evaluation Criteria A: No white streak occurs even on a solid black image. O: Some portions of the solid black image have a slightly darker density (not white). X: On the solid black image. , White streaks can be confirmed, a level that causes problems in use.

  Table 3 shows the evaluation results.

  As apparent from Table 3, the toner images formed using the “toners Bk1 to Bk10”, “toners C1 to C10”, “toners M1 to M10”, and “toners Y1 to Y10” of the present invention are evaluated. It turns out that the item is also excellent. On the other hand, the toner images formed using the “toners Bk11 to Bk14”, “toners C11 to C14”, “toners M11 to M14”, and “toners Y11 to Y14” in the comparative examples have problems in some of the evaluation items. I understand that.

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 (type using a pressure roller and a heating roller) used by this invention. It is the schematic which shows an example of the fixing device (type using a belt and a heating roller) used by this invention. It is the schematic which shows an example of the fixing device (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 (8)

In an electrophotographic toner containing a binder resin and a colorant,
The electrophotographic toner comprises liquid paraffin;
An electrophotographic toner having a weight average molecular weight of 5,000 to 50,000 in a gel permeation chromatograph of the electrophotographic toner. In an electrophotographic toner containing a binder resin and a colorant,
The electrophotographic toner contains liquid paraffin and a releasing agent having a melting point of 50 to 100 ° C.
The electrophotographic toner according to claim 1, wherein the electrophotographic toner has a polymerization average molecular weight of 5,000 to 50,000 in gel permeation chromatograph. 3. The electrophotographic toner according to claim 1, wherein a peak top molecular weight of the liquid paraffin in a gel permeation chromatograph is 200 to 600. 4. 4. The electrophotographic toner according to claim 1, wherein the electrophotographic toner has a glass transition temperature (Tg) of 20 to 45 ° C. 5. 5. The electrophotographic toner according to claim 1, wherein the toner for electrophotography has a core-shell structure in which a shell is provided on a core particle surface, and the core particle includes the liquid paraffin. Toner for electrophotography. The electrophotographic toner according to claim 1, wherein the electrophotographic toner is prepared by an emulsion association method. The toner for electrophotography is obtained by adding a small particle size external additive having a number average primary particle size of 10 to 60 nm and a large particle size external additive having a number average primary particle size of 80 nm to 1 μm as external additives. The electrophotographic toner according to claim 1, wherein the toner is an electrophotographic toner. An image forming method comprising: forming a toner image by performing multicolor development on a transfer material using the electrophotographic toner according to claim 1.

Images