JP2008112046A - Toner for electrostatic charge image development - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner for electrostatic charge image development, the toner prepared by externally adding compound oxide particles containing titanium atoms and capable of stably forming an image without losing fluidity of the toner even when the toner is left in an environment easily causing packing, such as the toner being left to stand for a long period of time. <P>SOLUTION: The toner for electrostatic charge image development is prepared by externally adding compound oxide particles containing titanium atoms more than silicon atoms and having an average primary particle diameter of 20 nm to 200 nm. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a toner for developing an electrostatic image, which is used for image formation of an electrophotographic system typified by a copying machine or a printer, and particularly uses a specific external additive.

  An electrostatic image developing toner that can be used for electrophotographic image formation (hereinafter also simply referred to as toner) is made by adding particles made of an inorganic compound or resin called an external additive to its surface. There are many things. Thus, the presence of the external additive improves the performance of the toner, such as chargeability and fluidity, and the use of the external additive is considered as one of the effective means for realizing good image formation. From such a background, studies have been made for the purpose of improving the performance of external additives.

  One of the external additive technologies is a so-called composite particle composed of two or more kinds of compounds. Examples of the technique of the external additive made of composite particles include an external additive containing two or more kinds of metal atoms belonging to a specific group in the periodic table (for example, see Patent Document 1), an amorphous silica region and a metal. Examples thereof include an external additive composed of an oxide region (see, for example, Patent Document 2). The toner using the composite particles as an external additive exhibits the characteristics of the compound used, and the toner performance is stable and stable even under severe conditions such as continuous use and environmental fluctuations. It is known that it is effective in maintaining for a long time.

By the way, electrophotographic image formation may be performed in a cold and dry environment, or on the other hand, because it may be performed in a high-temperature and high-humidity environment. Therefore, it is required that a toner image of a predetermined quality is created at any time. As described above, an external additive is used to stably maintain the toner performance against environmental fluctuations. For example, the chargeability of toner tends to increase significantly in low temperature and low humidity environments than in high temperature and high humidity environments, but the fluctuations in chargeability associated with such environments are also suppressed by composite external additives using titania. Is possible.
JP 2005-84295 A JP 2005-128128 A

  By the way, although the toner using the external additive containing titania described above has realized stabilization of chargeability against environmental fluctuations, fluidity due to formation of a compacted state between the toners called packing when the toner is stored at rest. Loss tends to occur. Although good fluidity is expressed while the toner is agitated, the image forming apparatus is turned off for a long period of time, or an unused cartridge containing the toner is kept for a long period of time. It was a problem that appeared when I was there.

  Patent Document 1 described above discloses the use of an external additive composed of composite particles having a titanium atom, but this problem is hardly mentioned, and the disclosed external additive containing a titanium atom is disclosed. When an agent was used, there was a concern about the realization of stable image formation.

  The toner of the present invention is obtained by externally adding composite oxide particles containing titanium atoms, and the fluidity of the toner is not lost even if the toner is placed in an environment where packing is likely to occur, such as standing for a long period of time. An object of the present invention is to provide a toner for developing an electrostatic image capable of forming a stable image.

  The present inventors have found that the problems of the present invention can be solved by any of the configurations described below.

  The invention according to claim 1 is an electrostatic image developing toner obtained by externally adding composite oxide particles containing at least silicon atoms and titanium atoms, wherein the composite oxide particles contain titanium atoms. A toner for developing electrostatic images, wherein the toner contains more than silicon atoms and has a primary particle size of 20 nm to 200 nm. "

  The invention according to claim 2 is: “The composite oxide particles contain titanium atoms and silicon atoms, and the ratio of silicon atoms to the total amount of metal elements in the composite oxide particles is 1% by mass or more and 20% by mass. The toner for developing an electrostatic charge image according to claim 1, wherein the toner is at least% by mass.

According to a third aspect of the present invention, “the composite oxide particles have a BET specific surface area of 20 m ² / g to 60 m ² / g and a bulk density of 100 g / liter to 400 g / liter”. The toner for developing an electrostatic charge image according to claim 1, wherein:

  According to a fourth aspect of the present invention, “the electrostatic charge image developing toner has a volume-based median diameter (D50) of 3 μm or more and 8 μm or less. The toner for developing an electrostatic image.

  In the present invention, in the toner obtained by externally adding composite oxide particles containing titanium atoms, the composite oxide particles having the above-described configuration can cause packing so far that the toner can be stored for a long period of time. Packing no longer occurs when toner is placed in an easy environment. That is, according to the present invention, even when the toner is stored for a long period of time, the fluidity of the toner is not lost, and stable image formation can be performed at any time regardless of the installation environment of the image forming apparatus. It became possible to do it.

  Recently, electrophotographic image forming apparatuses have also been developed in a field called light printing. Toners used in this field often perform image formation at a higher speed than office printing, and thus stricter charging stability is required. However, the toner according to the present invention is better when used. It is expected that image formation can be performed stably.

  The present invention relates to an electrostatic charge image developing toner obtained by externally adding composite oxide particles containing silicon atoms and titanium atoms.

  The composite oxide particles used in the present invention are so-called “silica-titanium composite oxide particles”, which are oxide particles containing silicon atoms and titanium atoms. In particular, the content of titanium atoms is silicon. More than the atomic content. That is, the composite oxide particles used in the present invention have a structure in which the content of titanium atoms is increased and a small amount of silicon atoms are added, so that packing does not occur even when stored for a long period of time. Thus, it is possible to provide a toner that maintains fluidity and exhibits predetermined charging performance without being influenced by the environment.

  The toner according to the present invention can obtain a certain level of charging performance regardless of the influence of the environment in which the image is formed due to the action of the titanium structure contained in the composite oxide. As a result, stable image formation is always possible. I came to be able to do it. Therefore, a good toner image can be obtained even when image formation is performed in a low-temperature and low-humidity environment where overcharging is likely to occur, and a good toner can be obtained even in a high-temperature and high-humidity environment where the image formation is severe. An image is obtained.

  The external addition treatment of titanium oxide particles represented by titania is one of the effective techniques for controlling the charge amount of toner, and further charge amount control can be realized by increasing the addition amount. However, when the amount of titanium oxide particles added to the surface of the toner particles is increased, a remarkable flow characteristic is exhibited when the toner is stirred, but there is a risk of forming a compacted state between the toner particles called packing during standing storage. . When the packing occurs, the toner does not flow and the toner stored in the bottle does not come out, or the so-called toner cartridge in which the toner storage portion and the developing device are integrated causes torque increase. This will hinder image formation. As described above, the toner with externally-treated titanium oxide particles is feared to deteriorate the flow characteristics, and there is a measure for obtaining stable flow characteristics even if the toner is stored for a long period of time. It was sought after.

  The reason why packing is likely to occur when a toner using an external additive made of titanium oxide particles is stored at rest is probably due to the electrostatic relaxation property of titanium oxide. That is, since the titanium oxide compound has a low electric resistance, it is considered that the titanium oxide compound has a property of releasing the charge of the toner adhering thereto. In addition, the toner that has lost its charge from titanium oxide has a weak electrostatic repulsive force acting between the particles, and as a result, voids between the toner particles disappear, forming a compacted state, and the fluidity of the toner is lost. It is estimated that packing will occur. As described above, the low resistance of titanium oxide reduces the chargeability of the toner. As a result, packing is presumed to occur in a stationary storage environment where there is little chance of charging due to friction or the like.

  The present inventor pays attention to the influence of the electrostatic relaxation property due to the low resistance of titanium oxide, and in an environment where the charge easily flows out from the toner surface like a stationary storage environment, the toner is added via an external additive. We examined the technology to prevent the electric charge from escaping. At the same time, we investigated external additives that also ensure the charging stability against environmental fluctuations caused by titanium oxide. And, it is thought that this problem can be solved by adding a substance that blocks the conductivity of titanium oxide in the particles containing titanium oxide, and this problem can be solved by adding a small amount of silicon atoms such as silica to the titanium oxide particles. Has been found to be resolved.

  Thus, according to the present invention, by using composite oxide particles containing a small amount of silicon atoms in titanium oxide as an external additive, the outflow of charges from titanium oxide is caused by the presence of a small amount of silicon atoms. It is presumed that the above problem has been solved by being blocked.

  The composite oxide containing a titanium atom and a silicon atom in the present invention is not particularly limited as long as it is an oxide containing a silicon atom and a titanium atom. Specifically, there are eutectic type oxides having both silicon atoms and titanium atoms in the crystal, and mixed crystal type oxides of oxides of silicon and titanium. Of these, eutectic type oxides are preferred because they tend to easily achieve the effect of solving the problems of the present invention.

  The oxide particles containing titanium atoms and silicon atoms will be further described.

  The oxide particles containing a titanium atom and a silicon atom that can be used in the present invention have a titanium atom content higher than that of a silicon atom. Specifically, the titanium atom is preferably 80% or more and contains silica. In addition, the above-mentioned ratio is mass%.

  The content of titanium atoms and silicon atoms in the oxide particles can be set, for example, by controlling the ratio of the raw material compounds used in the production process of the oxide particles. The method for controlling the ratio of the raw material compound is realized, for example, by controlling the ratio of silicon tetrachloride vapor and titanium tetrachloride vapor in the case of a gas phase method using silicon tetrachloride and titanium tetrachloride described later.

  For example, when preparing oxide particles of silicon atoms: titanium atoms = 1: 9, the amount of silicon tetrachloride vapor used: the amount of titanium tetrachloride used = 1: 9, whereby the oxide particles having the above ratio are obtained. It is possible to produce.

  Moreover, the content of titanium atoms and silicon atoms in the oxide particles can be measured by, for example, a fluorescent X-ray analyzer.

  An X-ray fluorescence analyzer (XRF) irradiates a sample with continuous X-rays to generate characteristic X-rays (fluorescent X-rays) unique to the elements constituting the sample. Then, the generated fluorescent X-ray is spectrally separated (spectral dispersion type) by a spectral crystal to generate a spectrum, the obtained spectrum is measured, and the constituent elements are quantitatively analyzed from the intensity.

  In the fluorescent X-ray analysis method, calibration curves are prepared with a fluorescent X-ray analyzer using oxide particles with known contents of titanium atoms and silicon atoms, and using the calibration curves, The content of titanium atoms and silicon atoms is obtained. Examples of the fluorescent X-ray analyzer include XRF-1800 (manufactured by Shimadzu Corporation) and ZSX-100E (manufactured by Rigaku Corporation).

Quantification of silicon atoms and titanium atoms using a fluorescent X-ray analyzer can be performed, for example, by the following procedure.
(1) First, a sample for preparing a calibration curve is prepared. A known amount of silicon dioxide is added to 100 parts by mass of styrene powder to produce a measurement pellet for silicon dioxide. Similarly, a known amount of titanium oxide is added to 100 parts by mass of styrene powder to produce a measurement pellet for titanium oxide.
(2) Each of the produced pellets is measured with a fluorescent X-ray analyzer, and a calibration curve is created from the peak intensity obtained from each sample for silicon dioxide or titanium oxide in styrene powder.
(3) Next, the oxide particles containing silicon atoms and titanium atoms used in the present invention are measured with a fluorescent X-ray analyzer, and the obtained peak intensity is collated with a calibration curve. Quantify the content of titanium atoms.

  In the fluorescent X-ray analysis, rhodium (Rh) Kα ray is used as the X-ray, and, for example, quantification is performed under an output condition of a tube voltage of 20 kV and a tube current of 100 mA. As the spectral crystal, known spectral crystals for silicon atoms and titanium atoms can be used.

  Furthermore, a known scintillation counter or a proportion counter can be used as a detector for detecting the spectrum.

  FIG. 1 shows the principle of generation of fluorescent X-rays and an outline of the analyzer.

  In addition, the content of silicon atoms and titanium atoms in the oxide particles can be quantified using an inductively coupled plasma spectrometer (ICP).

Next, the size of the composite oxide particles that can be used in the present invention will be described. The composite oxide particles containing silicon atoms and titanium atoms that can be used in the present invention have an average primary particle size of 20 nm to 200 nm based on the number, and particularly preferably 50 nm to 110 nm. The average primary particle size based on the number of oxide particles can be calculated from, for example, an electron micrograph. Specifically, it can be calculated by the following procedure.
(1) Take a photograph of a toner with a magnification of 30,000 times with a scanning electron microscope, and capture the photograph image with a scanner.
(2) In the image processing analyzer “LUZEX AP (manufactured by Nireco)”, the composite oxide particles present on the toner surface on the photographic image are binarized, and the horizontal ferret diameter is calculated for 10,000 particles. The average primary particle size is used.

  In addition to the method of taking a photograph of the toner as described above and utilizing the oxide particles present on the toner surface, the oxide particles are directly photographed with a scanning electron microscope, and the same procedure is performed from the photograph image. It is also possible to calculate the average primary particle size by

  In addition, the particle size of the composite oxide particles containing titanium atoms and silicon atoms can be controlled by, for example, the method of preparing the composite oxide particles and the raw material ratio.

Next, the BET specific surface area of the composite oxide particles containing silicon atoms and titanium atoms that can be used in the present invention will be described. The composite oxide particles containing silicon atoms and titanium atoms that can be used in the present invention preferably have a BET specific surface area of 20 m ² / g or more and 60 m ² / g or less. When the BET specific surface area is in the above range, the composite oxide particles are not embedded in the toner or detached from the toner surface, and an environment in which the composite oxide particles act stably as an external additive is formed. Is done.

  The BET specific surface area is a measurement method for calculating the specific surface area of particles by a gas adsorption method. In the calculation of the specific surface area of the particles by the gas adsorption method, gas molecules having a known adsorption occupation area such as nitrogen gas are adsorbed on the particles, and the specific surface area of the particles is calculated from the adsorption amount. The BET specific surface area is used to accurately calculate the amount of gas molecules directly adsorbed on the solid surface (monomolecular layer adsorption amount), and is calculated using a formula called the BET formula shown below.

  As shown in the following equation, the BET equation shows the relationship between the adsorption equilibrium pressure P when in an adsorption equilibrium state at a constant temperature and the adsorption amount V at that pressure, and is expressed as follows.

Formula 1:
P / V (Po−P) = (1 / VmC) + ((C−1) / VmC) (P / Po)
Where Po: saturated vapor pressure
Vm: Monolayer adsorption amount, when gas molecules form a monolayer on a solid surface
Adsorption amount
C: Parameter related to heat of adsorption (> 0)
Then, the surface area of the particles can be obtained by calculating the single molecule adsorption amount Vm from the above formula and multiplying this by the cross-sectional area occupied by one gas molecule.

  The BET specific surface area in the present invention is a value calculated by the following measurement method using an automatic specific surface area measuring apparatus “GEMINI 2360 (manufactured by Shimadzu Micromeritics)”.

  First, about 2 g of a complex oxide containing silicon atoms and titanium atoms is filled in a straight sample cell, and the inside of the cell is replaced with nitrogen gas (purity 99.999%) for 2 hours as a pretreatment. After substitution, nitrogen gas (purity 99.999%) is adsorbed and desorbed on the composite oxide pretreated in the measuring apparatus main body, and calculation is performed by a multipoint method (7-point method).

  Next, the bulk density of the composite oxide particles containing silicon atoms and titanium atoms that can be used in the present invention will be described. The composite oxide particles containing silicon atoms and titanium atoms that can be used in the present invention preferably have a bulk density of 100 g / liter to 400 g / liter. Here, the bulk density of the composite oxide particle is a value obtained by dividing the mass of the filled composite oxide particle by the volume of the container when the composite oxide particle is filled in a container of a known volume. This means the mass of the composite oxide particles per unit volume. That is, the bulk density means a density in a state where voids exist between the composite oxide particles.

  A toner using composite oxide particles having a bulk density of 100 g / liter or more and 400 g / liter or less as an external additive ensures a space between the toner particles, so that packing is more generated even when stored stationary. It is difficult to maintain the fluidity more reliably.

  The bulk density of the composite oxide particles can be measured by, for example, a commercially available Kawakita type bulk density measuring machine. Examples of commercially available Kawakita type bulk density measuring machines include IH-2000 type (manufactured by Seishin Enterprise Co., Ltd.), and actual bulk density measurement is performed in the following procedure.

  First, composite oxide particles are placed on a sieve having a mesh of a predetermined size, and the sample is dropped for 30 seconds at an arbitrary vibration strength. Thereafter, the vibration is stopped and the mixture is allowed to stand for 30 seconds, and then the bulk density (composite oxide particle mass / volume) is calculated by grinding.

  The amount of the composite oxide particles containing silicon atoms and titanium atoms that can be used in the present invention is preferably 0.1% by mass to 2.0% by mass with respect to 100 parts by mass of the colored particles. 0.3 mass% to 1.0 mass% is more preferable. In addition to the composite oxide particles that can be used in the present invention, for example, known external additives such as silica, metal soap, and organic fine particles can be used in combination. In particular, the combined use with silica is preferable because it gives more fluidity to the toner.

  Next, a method for producing composite oxide particles containing silicon atoms and titanium atoms that can be used in the present invention will be described. The method for producing composite oxide particles containing silicon atoms and titanium atoms that can be used in the present invention is not particularly limited. For example, the gas phase method is one of typical production methods. The gas phase method is a method for producing an oxide containing silicon atoms and titanium atoms by heating and vaporizing a raw material compound containing silicon atoms and titanium atoms, and burning the obtained gas. As a method for producing composite oxide particles such as oxide particles containing titanium atoms and silicon atoms by a vapor phase method, for example, a method for producing a mixed oxide by high thermal decomposition disclosed in Japanese Patent No. 32025573 This is one of the representative examples.

As a specific example of a procedure for producing composite oxide particles containing titanium atoms and silicon atoms that can be used in the present invention, a procedure for producing by a vapor phase method is introduced below.
(1) First, silicon tetrachloride SiCl ₄ and titanium tetrachloride TiCl ₄ as raw material compounds are heated and vaporized in separate evaporators.
(2) The vapor of these chlorides generated by vaporization is transferred into a mixing chamber equipped with a burner together with an inert gas such as nitrogen. The proportion of each chloride used at this time is directly reflected in the proportion of titanium atoms and silicon atoms in the composite oxide as the final product. Therefore, it is possible to control titanium atoms and silicon atoms in the composite oxide particles by adjusting the proportion of each chloride vapor used.
(3) In the mixing chamber, hydrogen and dry air or hydrogen and oxygen are mixed with the above-described chloride vapor, and combustion treatment is performed at a temperature of 1000 ° C. or higher. After combustion, composite oxide particles containing titanium atoms and silicon atoms are obtained.
(4) The produced composite oxide particles are cooled to about 110 ° C. and then collected using a filter.
(5) The collected composite oxide particles are treated with wet air at a temperature of 500 to 700 ° C. to remove raw material compounds such as residual chloride attached to the surface of the composite oxide particles. At the same time, the drying process is also performed.
(6) It is preferable to subject the composite oxide particles having undergone the above treatment to a hydrophobizing treatment. The hydrophobizing treatment is performed by the following procedure, for example. First, the composite oxide particles are put into a mixing container, 5 parts by mass of water having a pH of 7 is added to 100 parts by mass of the composite oxide particles, and further 10 parts by mass of a hydrophobizing agent (hexamethylsilazane) is sprayed. And mix for 20 minutes.
(7) Thereafter, a baking process is performed at a temperature of 200 ° C. for 4 hours, and then cooled. In order to prevent generation of secondary agglomerated particles after cooling, they are crushed by a mechanical pulverizer.

  Note that the degree of hydrophobicity of the produced composite oxide particles can be measured by the following method. 50 ml of water is put into a 200 ml beaker, and 0.2 g of composite oxide particles are further added. While stirring with a magnetic stirrer, methanol is added from a burette whose tip is immersed in water at the time of dropping. By adding methanol, the composite oxide particles that have initially floated begin to sink gradually, and the amount of methanol dropped when completely sinking is read and calculated from the following formula.

Hydrophobic degree (%) = [(ml methanol dropped) / (50 + ml methanol dropped)
)] X 100
In addition to the silane coupling agent represented by the aforementioned hexamethylsilazane, the hydrophobizing agent used when performing the hydrophobizing treatment is a surface of a titanate coupling agent, silicone oil, silicone varnish, or the like. What is used as a processing agent is mentioned. Furthermore, a fluorine-based silane coupling agent, a fluorine-based silicone oil, a coupling agent having an amino group or a quaternary ammonium base, a modified silicone oil, or the like can also be used. The hydrophobizing agent is preferably used after being dissolved in a solvent such as ethanol.

  Next, the toner according to the present invention will be described. First, the size of the toner according to the present invention will be described.

  The toner for developing an electrostatic charge image according to the present invention is obtained by externally adding the above-mentioned “composite oxide particles containing silicon atoms and titanium atoms”, and coloring particles constituting the toner (before external addition treatment) The method for producing the particles is not particularly limited.

  Further, the toner according to the present invention preferably has a volume-based median diameter (D50) of 3 μm or more and 8 μm or less, and toner belonging to such a small diameter class is a high-definition compatible with digital technology that has recently attracted attention. It is the best for the reproduction of a simple dot image. In particular, in recent years, an electrophotographic image forming apparatus is also used in the field of light printing called on-demand printing, and creation of a printed matter using a toner image is being promoted without taking the trouble of generating a plate.

  Therefore, by using the small-diameter toner externally added with the above-described composite oxide particles for such a field, it is composed of a high-definition dot image that is not inferior to a photographic image or a printed image even in a severe image forming environment. A printed material can be produced. From the viewpoint of faithfully reproducing a fine dot image, a toner composed of colored particles formed by a polymerization method that can be produced while controlling the shape and size of the particles in the production process is preferable.

  The aforementioned volume-based median diameter (D50) is measured using, for example, a device in which a computer system equipped with data processing software “Software V3.51” is connected to “Multisizer 3 (manufactured by Beckman Coulter)”. Can be calculated.

  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 poured into a beaker containing ISOTON II (manufactured by Beckman Coulter) 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 25,000. To do. The aperture size of the multisizer 3 is 50 μm.

  Next, a toner manufacturing method according to the present invention will be described.

  The colored particles constituting the toner according to the present invention contain at least a resin and a colorant. The toner according to the present invention enables faithful reproduction of a minute dot image by setting the median diameter (D50) on a volume basis within the above-described range. The small-diameter toner is preferably produced by a polymerization method capable of forming particles by adding an operation for controlling the particle size and shape in the production process. Among them, the emulsion association method in which resin fine particles of about 120 nm are formed in advance by an emulsion polymerization method or a suspension polymerization method, and colored particles having the above-mentioned particle diameter are formed through a process of aggregating the resin fine particles is effective. It can be said that this is one of the manufacturing methods.

  Hereinafter, toner production by an emulsion association method, which is an example of a toner production method according to the present invention, will be described. Toner preparation by the emulsion association method is performed through the following steps.

(1) Production process of resin fine particle dispersion (2) Production process of colorant fine particle dispersion (3) Aggregation / fusion process of resin fine particles, etc. (4) Aging process (5) Cooling process (6) Washing process (7 ) Drying step (8) External additive treatment step Hereinafter, each step will be described.

(1) Production process of resin fine particle dispersion This process is a process of forming resin fine particles having a size of about 100 nm by introducing a polymerizable monomer that forms resin fine particles into an aqueous medium and performing polymerization. . It is also possible to form a resin fine particle containing wax. In this case, when the wax is dissolved or dispersed in the polymerizable monomer and polymerized in an aqueous medium, resin fine particles containing the wax are formed.

(2) Colorant fine particle dispersion preparation step In this step, a colorant is dispersed in an aqueous medium to prepare a colorant fine particle dispersion having a size of about 110 nm.

(3) Aggregation / fusion process of resin fine particles In this step, resin fine particles and colorant particles are aggregated in an aqueous medium, and these aggregated particles are fused, and these particles are aggregated. Is a step corresponding to a so-called “step of agglomerating resin fine particles”.

  In this step, an aggregating agent such as an alkali metal salt or alkaline earth metal salt represented by magnesium chloride is added to an aqueous medium in which resin fine particles and colorant particles are present, and then the resin fine particles By heating to a temperature not lower than the glass transition point and not lower than the melting peak temperature (° C.) of the mixture, agglomeration is advanced and simultaneously the resin fine particles are fused.

  Then, when agglomeration is advanced and the size of the particles reaches a target, a salt such as salt is added to stop the aggregation.

(4) Ripening step This step is a step of aging the reaction system until the desired average circularity is achieved by heat-treating the reaction system subsequent to the aggregation / fusion step.

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

(6) Washing step This step comprises a step of solid-liquid separation of the colored particles from the colored particle dispersion cooled to a predetermined temperature in the above step, and a cake-like aggregate called a wet toner cake that has been solid-liquid separated. It consists of a washing process for removing deposits such as surfactants and flocculants from the colored particles.

  In the washing treatment, water washing is performed until the electric conductivity of the filtrate becomes, for example, about 10 μS / cm. Examples of the filtration method include a centrifugal separation method, a vacuum filtration method using Nutsche and the like, and a filtration method using a filter press and the like, and are not particularly limited.

(7) Drying step This step is a step of drying the washed colored particles to obtain dried colored particles. Examples of the dryer used in this step include a spray dryer, a vacuum freeze dryer, and a vacuum dryer, and a stationary shelf dryer, a mobile shelf dryer, a fluidized bed dryer, and a rotary dryer. It is preferable to use a stirring dryer or the like.

  The water content of the dried colored particles is preferably 5% by mass or less, more preferably 2% by mass or less. In addition, when the dried colored particles are aggregated by weak interparticle attractive force, the aggregate may be crushed. Here, as the crushing treatment apparatus, a mechanical crushing apparatus such as a jet mill, a Henschel mixer, a coffee mill, or a food processor can be used.

(8) External additive treatment step This step is a step of preparing a toner by adding external additives such as the above-mentioned composite oxide particles containing silicon atoms and titanium atoms to dried colored particles. . Examples of the external additive mixing device include mechanical mixing devices such as a Henschel mixer and a coffee mill.

  Through the above steps, the toner according to the present invention can be produced.

  Next, the resin, colorant, wax and the like constituting the toner according to the present invention will be described with specific examples.

  First, as a resin that can be used in the toner according to the present invention, a polymer obtained by polymerizing a polymerizable monomer as described below can be used.

  The resin according to the present invention contains a polymer obtained by polymerizing at least one polymerizable monomer as a constituent component. Examples of the polymerizable monomer include styrene, o-methylstyrene, m- Methylstyrene, p-methylstyrene, α-methylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert-butylstyrene, p Styrene or styrene derivatives such as -n-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, methyl methacrylate, ethyl methacrylate, methacryl N-butyl acid, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, Methacrylate derivatives such as n-octyl acrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, methyl acrylate, ethyl acrylate, acrylic Acrylate derivatives such as isopropyl acid, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, phenyl acrylate, Olefins such as ethylene, propylene and isobutylene, vinyl esters such as vinyl propionate, vinyl acetate and vinyl benzoate, vinyl such as vinyl methyl ether and vinyl ethyl ether Vinyl ketones such as ethers, vinyl methyl ketone, vinyl ethyl ketone, vinyl hexyl ketone, N-vinyl compounds such as N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone, vinyl compounds such as vinyl naphthalene, vinyl pyridine, etc. And acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, and acrylamide. These vinyl monomers can be used alone or in combination.

  Moreover, it is also possible to use combining what has an ionic dissociation group as a polymerizable monomer which comprises resin. For example, it has a substituent such as a carboxyl group, a sulfonic acid group, and a phosphoric acid group as a constituent group of the monomer, and specifically includes acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumaric acid. Examples include acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester, styrene sulfonic acid, allyl sulfosuccinic acid, 2-acrylamido-2-methylpropane sulfonic acid, and acid phosphooxyethyl methacrylate.

  Furthermore, polyfunctionality 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.

  Known colorants can be used for the toner according to the present invention. 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.

  Further, as a colorant for green or cyan, 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 can 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.

  Examples of the wax that can be used in the toner according to the present invention include conventionally known waxes. Specifically, polyolefin waxes such as polyethylene wax and polypropylene wax, long-chain hydrocarbon waxes such as paraffin wax and sazol wax, dialkyl ketone waxes such as distearyl ketone, carnauba wax, montan wax, and trimethylolpropane. Tribehenate, pentaerythritol tetramyristate, pentaerythritol tetrastearate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18-octadecanediol distearate, trimellit Esters such as tristearyl acid, distearyl maleate, ethylenediamine dibehenyl amide, trimellitic acid tristearyl amide, etc. Such as amide waxes.

  The melting point of the wax is usually 40 to 160 ° C, preferably 50 to 120 ° C, more preferably 60 to 90 ° C. By setting the melting point within the above range, the heat-resistant storage stability of the toner is ensured, and stable toner image formation can be performed without causing cold offset or the like even when fixing at a low temperature. Further, the wax content in the toner is preferably 1% by mass to 30% by mass, and more preferably 5% by mass to 20% by mass.

  The toner according to 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 0.1 to 0.5 μm magnetic particles in the toner can be used.

  The toner according to the present invention can also be used as a two-component developer by mixing with a carrier that is magnetic particles. As the carrier, conventionally known materials such as metals such as iron, ferrite, and magnetite, and alloys of these metals with metals such as aluminum and lead can be used. Among these, ferrite particles are preferable. The volume average particle size of the carrier is preferably 15 to 100 μm, more preferably 25 to 80 μm.

  Next, an image forming method using the toner according to the present invention will be described. First, an image forming method using the toner according to the present invention as a two-component developer will be described.

  FIG. 2 is a schematic view showing an example of an image forming apparatus that can be used when the toner according to the present invention is a two-component developer.

  In FIG. 2, 1Y, 1M, 1C and 1K are photosensitive members, 4Y, 4M, 4C and 4K are developing means, 5Y, 5M, 5C and 5K are primary transfer rolls as primary transfer means, and 5A is a secondary transfer. Secondary transfer rolls as means, 6Y, 6M, 6C and 6K are cleaning means, 7 is an intermediate transfer member unit, 24 is a heat roll type fixing device, and 70 is an intermediate transfer member.

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

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

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

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

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

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

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

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

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

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

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

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

  Next, an image forming method when the toner according to the present invention is used as a non-magnetic one-component developer will be described. FIG. 3 shows an example of a full-color image forming apparatus that uses a non-magnetic one-component developer. Note that the image forming apparatus 100 illustrated in FIG. 3 is a typical image forming apparatus in which the above-described developing device 20 can be mounted. The image forming apparatus shown in FIG. 3 includes a charging brush 2 for uniformly charging the surface of a photosensitive drum 1 to a predetermined potential around a rotating electrostatic latent image carrier (hereinafter also referred to as a photosensitive drum) 1, and a photosensitive member. A cleaner 6 for removing residual toner on the drum 1 is provided.

  The laser scanning optical system 3 scans and exposes the photosensitive drum 1 uniformly charged by the charging brush 2 to form an electrostatic latent image on the photosensitive drum 1. The laser scanning optical system 3 includes a laser diode, a polygon mirror, and an fθ optical element, and print data for each of yellow, magenta, cyan, and black is transferred from the host computer to the control unit. Based on the print data for each color, a laser beam is sequentially output, and the photosensitive drum 1 is scanned and exposed to form an electrostatic latent image for each color.

  The developing device unit 40 that accommodates the developing device 4 supplies toner of each color to the photosensitive drum 1 on which the electrostatic latent image is formed to perform development. The developing device unit 40 is provided with four developing devices 4Y, 4M, 4C, and 4Bk each containing non-magnetic one-component toners of yellow, magenta, cyan, and black around the support shaft 33. Rotating to the center, each developing device 4 is guided to a position facing the photosensitive drum 1.

  The developing device unit 40 rotates around the support shaft 33 each time an electrostatic latent image of each color is formed on the photosensitive drum 1 by the laser scanning optical system 3, and stores the corresponding color toner. 4 is guided to a position facing the photosensitive drum 1. Then, each of the developing devices 4Y, 4M, 4C, and 4Bk sequentially supplies each charged color toner to the photosensitive drum 1 for development.

  In the image forming apparatus of FIG. 3, an endless intermediate transfer belt 7 is provided downstream of the developing device unit 40 in the rotation direction of the photosensitive drum 1, and is driven to rotate in synchronization with the photosensitive drum 1. The intermediate transfer belt 7 comes into contact with the photosensitive drum 1 at a portion pressed by the primary transfer roller 5 and transfers a toner image formed on the photosensitive drum 1. Further, a secondary transfer roller 73 is rotatably provided so as to face the support roller 72 that supports the intermediate transfer belt 7, and on the intermediate transfer belt 7 at a portion where the support roller 72 and the secondary transfer roller 73 face each other. The toner image is pressed and transferred onto a recording material P such as recording paper.

  A cleaner 8 for removing residual toner on the intermediate transfer belt 7 is provided between the full-color developing device unit 40 and the intermediate transfer belt 7 so as to be able to contact with and separate from the intermediate transfer belt 7.

  The paper feeding means 60 that guides the recording material P to the intermediate transfer belt 7 includes a paper feeding tray 61 that houses the recording material S, and a paper feeding roller 62 that feeds the recording material S stored in the paper feeding tray 61 one by one. It comprises a timing roller 63 that feeds the fed recording material S to the secondary transfer site.

  The recording material P to which the toner image has been pressed and transferred is conveyed to the fixing device 24 by a conveying means 66 constituted by an air suction belt or the like, and the toner image transferred by the fixing device 24 is fixed on the recording material P. After fixing, the recording material P is transported through the vertical transport path 80 and discharged onto the upper surface of the apparatus main body 100.

  The image forming apparatus shown in FIG. 3 is one in which a replaceable developing device 4 is loaded to form an image. The developing device 4 shown in FIG. 4A is usually called a toner cartridge, and stores a predetermined amount of toner inside a part where components such as a developing roller are arranged. The developing device supplied in the form of a toner cartridge is loaded at a predetermined position in the image forming apparatus, and then the developer stored therein is supplied to the photosensitive drum for development, and a predetermined number of images are formed and developed. When the agent runs out, it is removed from the apparatus and a new toner cartridge is loaded.

  FIG. 4B is a schematic diagram illustrating an example of a cross-sectional configuration of the developing device 4. Hereinafter, the developing device 4 is also referred to as a toner cartridge 4. The toner cartridge 4 has a buffer chamber 42 adjacent to the developing roller 41 and a hopper 43 adjacent to the buffer chamber 42.

  The developing roller 41 has a conductive cylindrical base and an elastic layer formed on the outer periphery of the base using a material having high hardness such as silicone rubber.

  In the buffer chamber 42, a blade 44, which is a toner regulating member, is disposed in pressure contact with the developing roller 41. The blade 44 regulates the charge amount and adhesion amount of toner on the developing roller 41. It is also possible to further provide an auxiliary blade 45 for assisting regulation of the toner charge amount and adhesion amount on the developing roller 41 on the downstream side of the blade 41 with respect to the rotation direction of the developing roller 41.

  A supply roller 46 is pressed against the developing roller 41. The supply roller 46 is driven to rotate in the same direction as the developing roller 41 (counterclockwise direction in the drawing) by a motor (not shown). The supply roller 46 has a conductive cylindrical substrate and a foam layer formed of urethane foam or the like on the outer periphery of the substrate.

  The hopper 43 contains toner T as a one-component developer. The hopper 43 is provided with a rotating body 47 for stirring the toner. A film-like conveying blade is attached to the rotating body 47, and the toner is conveyed by the rotation of the rotating body 47 in the arrow direction. The toner conveyed by the conveying blades is supplied to the buffer chamber 42 through a passage 44 provided in a partition wall that separates the hopper 43 and the buffer chamber 42. The shape of the conveying blade is bent while conveying the toner in front of the rotation direction of the blade as the rotating body 47 rotates, and returns to a straight state when the left end of the passage 48 is reached. In this way, the blades return the toner to the passage 48 by returning the shape straight after passing through the curved state.

  The passage 48 is provided with a valve 321 for closing the passage 48. This valve is a film-like member, one end of which is fixed to the upper right side surface of the passageway 48 of the partition wall. When toner is supplied from the hopper 43 to the passageway 48, the passageway 48 is opened by being pushed rightward by the pressing force from the toner. It is like that. As a result, toner is supplied into the buffer chamber 42.

  Further, a regulating member 322 is attached to the other end of the valve 321. The regulating member 322 and the supply roller 46 are arranged so as to form a slight gap even when the valve 321 closes the passage 48. The regulating member 322 adjusts so that the amount of toner accumulated at the bottom of the buffer chamber 42 does not become excessive, so that a large amount of toner collected from the developing roller 41 to the supply roller 46 does not fall to the bottom of the buffer chamber 42. Adjusted.

  In the toner cartridge 4, the developing roller 41 is rotated in the direction of the arrow during image formation, and the toner in the buffer chamber 42 is supplied onto the developing roller 41 by the rotation of the supply roller 46. The toner supplied onto the developing roller 41 is charged and thinned by a blade 44 and an auxiliary blade 45 and then transported to a region facing the image carrier to develop an electrostatic latent image on the image carrier. Provided. The toner that has not been used for development returns to the buffer chamber 42 as the developing roller 41 rotates, and is scraped and collected from the developing roller 41 by the supply roller 46.

  The toner image formed with the toner according to the present invention is finally transferred onto a transfer material and fixed on the transfer material by a fixing process, thereby forming an image. The transfer material P used for the image formation is a support for holding a toner image, and is usually called an image support, a recording material, or transfer paper. Specifically, plain paper and high-quality paper from thin paper to thick paper, coated printing paper such as art paper and coated paper, commercially available Japanese paper and postcard paper, various transfer materials such as plastic film for OHP, cloth, etc. However, it is not limited to these.

Examples of the present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.
1. Production of Composite Oxide Particles 1-11 Silicon tetrachloride and titanium tetrachloride were heated and vaporized in separate evaporators based on the procedure described above. After the obtained silicon tetrachloride vapor and titanium tetrachloride vapor were mixed, these chloride vapors were burned to produce composite oxide particles shown in Table 1. The mixing ratio of silicon tetrachloride vapor and titanium tetrachloride vapor was changed as shown in Table 1 to adjust the content of titanium atoms and silicon atoms in the composite oxide particles. Moreover, vaporization and combustion were performed with the heating temperature in the evaporator and the temperature in the treatment chamber where combustion was performed at 550 ° C.

  The composite oxide particles 10 are obtained by mixing aluminum tetrachloride vapor 15 with titanium tetrachloride vapor 85 and performing combustion treatment, and the composite oxide particles 11 are obtained by performing combustion treatment using only titanium tetrachloride. It is a thing.

  Table 1 shows the average primary particle size, BET specific surface area, and bulk density of the obtained composite oxide. The average primary particle size was calculated by taking an electron micrograph in the above-described procedure using the toner obtained by the toner preparation process described later. Further, the BET specific surface area and the bulk density are calculated based on the measurement procedure described above.

2. Preparation of Toners 1 to 16 Non-magnetic “Toners 1 to 16” were prepared based on the following procedure.
2-1. Preparation of Resin Particle Dispersion (1HML) (1) Preparation of Resin Particle Dispersion (1H) 7.08 parts by mass of sodium lauryl sulfate was added to a separable flask equipped with a stirrer, temperature sensor, cooling tube, and nitrogen introducing device. A surfactant solution (aqueous medium) was prepared by dissolving in 3010 parts by mass of ion-exchanged water. This surfactant solution was heated to 80 ° C. while stirring at a stirring speed of 230 rpm under a nitrogen stream.

  To this surfactant solution was added an initiator solution in which 9.2 parts by mass of a polymerization initiator (potassium persulfate: KPS) was dissolved in 200 parts by mass of ion-exchanged water, and the temperature was adjusted to 75 ° C. A monomer mixture containing the compound shown was added dropwise over 1 hour.

Styrene 77.8 parts by weight n-Butyl acrylate 17.7 parts by weight Acrylic acid 2.52 parts by weight The reaction system obtained by dropping the monomer mixture is heated and stirred at 75 ° C. for 2 hours for polymerization. To prepare a resin particle dispersion. This is designated as “resin particle dispersion (1H)”.
(2) Preparation of resin particle dispersion (1HM) A monomer mixture containing the following compound was prepared in a flask equipped with a stirrer.

Styrene 104.1 parts by mass n-butyl acrylate 28.4 parts by mass Acrylic acid 3.49 parts by mass n-octyl-3-mercaptopropionic acid ester 5.6 parts by mass
98.0 parts by mass of pentaerythritol tetrabehenate was added and dissolved by heating to 90 ° C.

  On the other hand, 1.6 parts by mass of sodium lauryl sulfate was dissolved in 2700 parts by mass of ion-exchanged water to prepare a surfactant solution (aqueous medium), which was heated to 98 ° C. In this surfactant solution, 28 parts by mass of the above-mentioned “resin particle dispersion (1H)” in terms of solid content was added, and then the monomer mixture containing pentaerythritol tetrabehenate was added. .

  Then, using a mechanical disperser “CLEAMIX (manufactured by M Technique Co., Ltd.)” having a circulation path, the emulsified dispersion liquid containing emulsified particles (oil droplets) is mixed and dispersed for 8 hours. Was prepared.

Next, an initiator solution in which 5.1 parts by mass of a polymerization initiator (KPS) was dissolved in 240 parts by mass of ion-exchanged water and 750 parts by mass of ion-exchanged water were added to this emulsified dispersion. Thereafter, the temperature of the system was raised to 98 ° C., and polymerization was carried out by heating and stirring for 12 hours to prepare a resin particle dispersion composed of a composite resin. This is referred to as “resin particle dispersion (1HM)”.
(3) Preparation of resin particle dispersion (1HML) The above-mentioned “resin particle dispersion (1HM)” was adjusted to 80 ° C., and a monomer mixture containing the following compound was dropped into this over 1 hour. did.

Styrene 298 parts by mass n-butyl acrylate 93.6 parts by mass Acrylic acid 10.3 parts by mass n-octyl-3-mercaptopropionate 10.4 parts by mass After completion of dropping, 7.4 parts by mass of a polymerization initiator (KPS) Was added to 200 parts by mass of ion-exchanged water, and polymerization was performed by heating and stirring for 2 hours. Thereafter, the reaction system was cooled to 28 ° C. to prepare a resin particle dispersion. This is referred to as “resin particle dispersion (1HML)”.
2-2. Preparation of Colorant Dispersion 1 90 parts by weight of sodium lauryl sulfate was added to 1600 parts by weight of ion-exchanged water, and this was stirred and dissolved to prepare a surfactant solution (aqueous medium). The following colorant was gradually added while stirring the surfactant solution.

C. I. Pigment Blue 15: 3 400.0 parts by mass After the above colorant is added, using a stirrer “CLEARMIX (M Technique Co., Ltd.)”, dispersion treatment is performed until the particle size of the colorant becomes 200 nm or less. A colorant dispersion was prepared. The resulting colorant dispersion is referred to as “Colorant Dispersion 1”.
2-3. Preparation of colored particles 1C to 3C (1) Preparation of colored particles 1C The following were charged into a reaction vessel equipped with a temperature sensor, a cooling tube, a nitrogen introducing device, and a stirring device, and stirred.

"Resin particle dispersion (1HML)" 200 parts by mass (in terms of solid content)
3000 parts by weight of ion-exchanged water 33 parts by weight of “colorant dispersion 1” After adjusting the temperature in the reaction vessel to 30 ° C., a 5 mol / liter sodium hydroxide aqueous solution was added to the reaction solution to adjust the pH to 10.0. Adjusted.

  Subsequently, an aqueous solution in which 52.6 parts by mass of magnesium chloride hexahydrate was dissolved in 72 parts by mass of ion-exchanged water was added at 30 ° C. for 10 minutes with stirring. After 3 minutes from the end of the addition, the temperature increase was started, and the temperature of the reaction system was raised to 90 ° C. over 60 minutes to advance the aggregation. The size of the particles formed by aggregation was observed with “Multisizer 3”.

  When the volume-based median diameter reached 6.5 μm, an aqueous solution in which 115 parts by mass of sodium chloride was dissolved in 700 parts by mass of ion-exchanged water was added to stop aggregation.

  Further, the liquid temperature was set to 90 ° C. ± 2 ° C., and heating and stirring were continued for 6 hours, the liquid temperature was cooled to 30 ° C., hydrochloric acid was added to adjust pH to 2.0, and stirring was stopped.

The produced colored particles are separated into solid and liquid, and washing with ion-exchanged water is repeated 4 times (the amount of ion-exchanged water used at one time is 15 liters), followed by drying with hot air at 40 ° C. Colored particles 1C ”were produced. It was 110 degreeC when the softening point of the obtained colored particle was measured using the above-mentioned "flow tester CFT-500 (made by Shimadzu Corporation Corp.)".
(2) Preparation of colored particles 2C In the preparation of “colored particles 1C”, the same procedure was performed except that the aggregation was stopped by adding the sodium chloride aqueous solution when the size of the particles formed by aggregation reached 3.0 μm. The “colored particle 2C” was prepared by the procedure described above.
(3) Preparation of colored particles 3C In the preparation of “colored particles 1C”, the same procedure was performed except that the aggregation was stopped by adding the sodium chloride aqueous solution when the size of the particles formed by aggregation reached 8.0 μm. The “colored particle 3C” was prepared by the procedure described above.
2-4. Preparation of Toners 1 to 16 As shown in Table 2, the “colored particles 1C to 3C” were combined with “composite oxide particles 1 to 11” shown in Table 1 to perform an external addition treatment to prepare toners. . In addition, the external addition process added the following amount of external additives with respect to 100 mass parts of colored particles.

Composite oxide particles shown in Table 1 Amounts shown in Table 2 (unit: parts by mass)
0.8 parts by mass of hydrophobic silica having a number average primary particle size of 12 nm and a hydrophobization degree of 65 After adding these, a Henschel mixer “FM10B (Mitsui Miike Chemical Co., Ltd.)” was used at a peripheral speed of 30 m / sec. Mixing for 10 minutes produced a non-magnetic toner. The obtained toners are designated “toners 1 to 15”. In addition, a toner was prepared by adding 1.8 parts by mass of the hydrophobic silica without using the composite oxide particles shown in Table 1 to “colored particles 1C”, and this was designated as “toner 16”.
3. Evaluation Experiment The toner cartridge shown in FIG. 4 is prepared for the amount of toner, and each toner cartridge contains “toner 1 to 16” in an amount capable of creating 5000 prints with A4. (20 ° C., 55% RH) for 25 days and 50 days. The toner cartridges containing “toners 1 to 16” were designated as “Examples 1 to 11” and “Comparative Examples 1 to 5” as shown in Table 2.

3-1. Evaluation 1 (Evaluation of storage stability (packing occurrence))
The storage stability (packing occurrence) was evaluated by evaluating the removal state of the toner stored from each of the stored toner cartridges. The state of toner discharge from the toner storage port was evaluated with the toner storage port facing downward, and 20 ml of discharged toner was sampled and visually evaluated for the presence of toner lumps. Evaluation was as follows, and ◎, ○, and Δ were acceptable.

<Evaluation details>
A: There is no feeling of being caught in the toner storage opening after discharging after storage for 50 days, and no toner lump is seen. No problem with toner discharge ○: There is no feeling of being caught in the toner storage port after storage for 25 days, and there is no toner lump, and there is a slight feeling of catching after discharging for 50 days. However, the toner lump was not seen and the toner was smoothly discharged. △: The toner was discharged and the toner lump was not seen although the torque was applied to the stirring portion when discharged after storage for 25 days. No problem x: At the time of discharging after storage for 25 days, torque was applied to the agitating part and toner could not be discharged, or even if it was discharged, there was a toner lump.
3-2. Evaluation 2 (image evaluation)
The toner cartridge stored on the 25th is loaded into the full-color image forming apparatus shown in FIG. 3 and is first subjected to a normal temperature and humidity environment (20 ° C., 55% RH) and a high temperature and high humidity environment (30 ° C., 80% RH). In addition, under a low-temperature and low-humidity environment (10 ° C., 20% RH), 1500 continuous prints were prepared, and the following evaluation was performed.

  An original image (A4 size original image in which a fine line image, a halftone image, a white background image, and a solid image are each divided into ¼ equal parts) was used for a series of print creations.

  The conditions such as the surface material and surface temperature of the heating roller constituting the fixing device of the image forming apparatus were as follows.

Fixing speed: 230mm / sec
Heat roller surface material: Polytetrafluoroethylene (PTFE)
Heating roller surface temperature: 125 ° C (however, set as follows when evaluating texture fixing strength)
<Density fluctuation>
The solid image density on the 10th print and 1500th print after the start of continuous printing was measured using a Macbeth reflection densitometer (RD-918), and the density fluctuation at the start and end of continuous printing was evaluated. In the evaluation, the reflection density at five locations on the printed solid image was randomly measured to calculate an average value, and the density difference at the start and end was obtained. A density difference of 0.05 or less was accepted.

<Filming>
Filming was evaluated by visually observing the surface of the photoreceptor, the intermediate transfer member, and the last printed image under each environment after continuous printing. For the printed image, the occurrence of filming was evaluated based on the presence or absence of toner stains on the print.

○: No filming occurred on both the photoconductor and the intermediate transfer member. Δ: Filming occurred on at least one of the photoconductor and the intermediate transfer member, but not on the printed image. No, it was judged that there was no practical problem. X: Filming was observed on at least one of the photosensitive member and the intermediate transfer member, and it was confirmed on the printed image, and it was judged that there was a practical problem.

<Fog>
The solid white image and the halftone image on the final print image created under each environment were visually evaluated to evaluate the occurrence of fog. Evaluation: ○: No occurrence of fog and no problem. △: Slight occurrence of fog, but not observed on image. ×: Occurrence of fog, observed on image. , ○ and △ were accepted.

<Reproducibility of thin lines>
The fine wire portion was enlarged using a 10-fold magnifier, and the number of fine wires confirmed in 1 mm was visually evaluated. Specifically, the fine line image on the original image is composed of three types of fine line images of 4 lines / mm, 5 lines / mm, and 6 lines / mm, and the thin line image forming the thin line image is blurred or swollen. The presence / absence of occurrence was evaluated, and 5 / mm or more was regarded as acceptable.

  The results are shown in Table 3.

  As shown in Table 3, in Examples 1 to 11 corresponding to the present invention, excellent storage stability and fine line reproducibility are expressed, and oxide particles containing titanium atoms contain a slight amount of silicon atoms. It was confirmed that the storage stability was improved.

  In Examples 1 to 11, it was confirmed that there was no problem of density fluctuation, filming, and fogging under any environment of normal temperature and normal humidity environment, high temperature and high humidity environment, and low temperature and low humidity environment. It was confirmed that stable image formation can be performed even under the forming environment. On the other hand, in Comparative Examples 1 and 2 using composite oxide particles having a higher proportion of silicon atoms than the toner of the example, stable image formation could not be performed.

  As described above, according to the toner for developing an electrostatic charge image having the configuration of the present invention, no packing is generated even when the toner is stored for a long time, and stable image formation can be performed under any image forming environment. It was confirmed.

It is a schematic diagram which shows the generation | occurrence | production principle of a fluorescent X ray, and the outline | summary of an analyzer. 1 is a schematic diagram illustrating an example of an image forming apparatus corresponding to a two-component developer. It is a schematic diagram showing an example of an image forming apparatus corresponding to a non-magnetic one-component developer. FIG. 2 is a schematic diagram illustrating an example of a developing device (toner cartridge).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging means 3 Exposure means 4 Developing means, developing device, toner cartridge 41 Developing roller 5 Primary transfer roll 6 Cleaning means 7 Endless belt-shaped intermediate transfer body unit 8 Fixing device 10 Image forming unit

Claims (4)

An electrostatic charge image developing toner comprising externally added composite oxide particles containing at least silicon atoms and titanium atoms,
The toner for developing an electrostatic charge image, wherein the composite oxide particles contain more titanium atoms than silicon atoms and have a primary particle diameter of 20 nm to 200 nm. The composite oxide particles contain titanium atoms and silicon atoms,
2. The electrostatic image developing toner according to claim 1, wherein the ratio of silicon atoms to the total amount of metal elements in the composite oxide particles is 1% by mass or more and 20% by mass or less. The composite oxide particles are:
BET specific surface area is 20 m ² / g or more and 60 m ² / g or less,
The toner for developing an electrostatic charge image according to claim 1, wherein the bulk density is 100 g / liter or more and 400 g / liter or less. 4. The electrostatic image developing toner according to claim 1, wherein the electrostatic charge image developing toner has a volume-based median diameter (D50) of 3 μm or more and 8 μm or less. 5.

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