JP2023126357A - Toner for electrostatic charge image development, electrostatic charge image developer, toner cartridge, process cartridge, image forming apparatus, and image forming method - Google Patents

Abstract

To provide a toner for electrostatic charge image development that prevents poor cleaning in any environment of a low temperature and low humidity environment and a high temperature and high humidity environment.SOLUTION: A toner for electrostatic charge image development has a toner particle and an external additive including silica particles. At least one of the toner particle and the external additive includes Ti-containing particles. The content of Ti is 0.05 ppm or more and 18 ppm or less. The silica particles include silica particles A having a BET specific surface area of 100 m2/g or more, and silica particles B having a BET specific surface area of 20 m2/g or more and 90 m2/g or less.SELECTED DRAWING: None

Description

The present invention relates to an electrostatic image developing toner, an electrostatic image developer, a toner cartridge, a process cartridge, an image forming apparatus, and an image forming method.

Patent Document 1 describes ``a toner for developing an electrostatic image comprising at least a binder resin and a colorant, wherein the binder resin includes a polyester resin, and the aluminum content according to fluorescent X-ray analysis is 0.005 to 0. A toner for developing an electrostatic image, characterized in that the titanium content is in the range of .040% by mass, and the titanium content is in the range of 50 to 500 ppm as determined by IPC emission spectroscopy.

Patent Document 2 describes an agglomerated toner in which an inorganic fine powder is attached to toner particles obtained by an aggregation method including an aggregation step and an aging step of at least polymer fine particles and colorant fine particles, the inorganic fine powder The toner uses at least silica having a number average particle size of primary particles of 80 to 300 nm and titanium oxide having a number average particle size of primary particles of 10 to 100 nm, and the peak molecular weight of the THF-soluble portion of the toner is 10,000 to 35,000. an agglomerated toner, wherein the specific surface area of the toner is 2.00 to 7.00 m ² /g, and the Si/Ti intensity ratio of the toner is 4.5 to 22.0. Disclosed.

Patent Document 3 describes "a toner containing toner particles containing at least a binder resin and a colorant, and at least alumina, wherein the alumina has a volume-based median diameter (D50) of 0.40 μm or more and 0.90 μm or less. The toner particles have an average circularity of 0.940 or more and 0.970 or less as measured by a flow type particle image analyzer, and contain Si element in a content of 100 ppm or more and 500 ppm or less, "A toner characterized by containing the Ti element in a content of 30 ppm or more and 1,000 ppm or less."

Japanese Patent Application Publication No. 2008-015334 JP2008-224881A Japanese Patent Application Publication No. 2011-028163

An object of the present invention is to provide a toner for developing an electrostatic image having toner particles and an external additive containing silica particles in a low-temperature, low-humidity environment and a high-temperature, high-temperature, It is an object of the present invention to provide a toner for developing an electrostatic image that suppresses cleaning failures in any wet environment.

Specific means for solving the above problems include the following aspects.

<1> Toner particles,
an external additive containing silica particles;
has
A toner for developing electrostatic images having a Ti content of 0.05 ppm or more and 18 ppm or less.
<2> The toner for developing an electrostatic image according to <1>, wherein the Ti content is 0.1 ppm or more and 15 ppm or less.
<3> The toner for developing an electrostatic image according to <1> or <2>, wherein at least one of the toner particles and the external additive contains Ti-containing particles.
<4> The toner for developing an electrostatic image according to <3>, wherein the Ti-containing particles are titanium oxide particles.
<5> Any one of <1> to <4>, wherein the volume average particle diameter of the toner particles is 4 μm or more and 9 μm or less, and the average circularity of the toner particles is 0.930 or more and 0.990 or less. The toner for developing electrostatic images described above.
<6> The toner for developing an electrostatic image according to any one of <1> to <5>, wherein the silica particles include silica particles having a BET specific surface area of 100 m ² /g or more.
<7> The toner for developing an electrostatic image according to <6>, wherein the silica particles having a BET specific surface area of 100 m ² /g or more have a number average particle diameter of 40 nm or more and 80 nm or less.
<8> Any one of <1> to <7>, wherein the ratio of the Ti content to the Si content (Ti content/Si content) is 2×10 ⁻⁶ or more and 2×10 ⁻² or less. The electrostatic image developing toner described in .
<9> An electrostatic image developer comprising the electrostatic image developing toner according to any one of <1> to <8>.
<10> A toner cartridge that accommodates the toner for developing an electrostatic image according to any one of <1> to <8> and is detachable from an image forming apparatus.
<11> A developing device containing the electrostatic image developer according to <9> and developing an electrostatic image formed on the surface of an image carrier as a toner image by the electrostatic image developer, A process cartridge that can be attached to and removed from a forming device.
<12> An image carrier, a charging means for charging the surface of the image carrier, an electrostatic image forming means for forming an electrostatic charge image on the charged surface of the image carrier, and the electrostatic charge according to <9>. a developing means containing a charge image developer and developing an electrostatic charge image formed on the surface of the image carrier as a toner image by the electrostatic charge image developer; and a toner formed on the surface of the image carrier. The image forming apparatus includes a transfer means for transferring an image onto the surface of a recording medium, a cleaning means having a cleaning blade for cleaning the surface of the image carrier, and a fixing means for fixing the toner image transferred to the surface of the recording medium. Image forming device.
<13> A charging step of charging the surface of the image carrier, an electrostatic image forming step of forming an electrostatic image on the charged surface of the image carrier, and the electrostatic image developer according to <9>, a developing step of developing the electrostatic charge image formed on the surface of the image carrier as a toner image; a transfer step of transferring the toner image formed on the surface of the image carrier onto the surface of a recording medium; and the image holding. An image forming method comprising: a cleaning step of cleaning the surface of the body with a cleaning blade; and a fixing step of fixing the toner image transferred to the surface of the recording medium.

According to the invention according to <1>, <3>, or <4>, in the toner for developing an electrostatic image having toner particles and an external additive containing silica particles, the Ti content is less than 0.05 ppm or 18 ppm. Provided is a toner for developing an electrostatic image that suppresses cleaning defects in both a low-temperature, low-humidity environment and a high-temperature, high-humidity environment, compared to a case where the toner exceeds the above.
According to the invention according to <2>, compared to cases where the Ti content is less than 0.1 ppm or more than 15 ppm, the electrostatic charge suppresses cleaning defects in both low temperature, low humidity environments and high temperature and high humidity environments. An image developing toner is provided.

According to the invention according to <5>, even if the volume average particle diameter of the toner particles is 4 μm or more and 9 μm or less, and the average circularity of the toner particles is 0.930 or more and 0.990 or less, the Ti content is 0. Compared to cases where the content is less than 0.05 ppm or greater than 18 ppm, an electrostatic image developing toner is provided that suppresses cleaning defects in both low temperature and low humidity environments and high temperature and high humidity environments.
According to the invention according to <6>, even when the silica particles include silica particles having a BET specific surface area of 100 m ² /g or more, the temperature is lower than that when the Ti content is less than 0.05 ppm or more than 18 ppm. Provided is a toner for developing electrostatic images that suppresses cleaning defects in both low-humidity environments and high-temperature, high-humidity environments.
According to the invention according to <7>, even if the silica particles having a BET specific surface area of 100 m ² /g or more have a number average particle diameter of 40 nm or more and 80 nm or less, the Ti content is less than 0.05 ppm or 18 ppm. Provided is a toner for developing an electrostatic image that suppresses cleaning defects in both a low-temperature, low-humidity environment and a high-temperature, high-humidity environment, compared to a case where the toner exceeds the above.
According to the invention according to <8>, the temperature and humidity are lower than when the ratio of Ti content to Si content (Ti content/Si content) is less than 2 × 10 ^-6 or more than 2 × 10 ^-2 . Provided is a toner for developing an electrostatic image that suppresses cleaning failures in both environments and high-temperature, high-humidity environments.

According to the invention according to <9>, in a toner for developing an electrostatic image having a Ti content of less than 0.05 ppm or more than 18 ppm, the toner for developing an electrostatic image has a toner particle and an external additive containing silica particles. In comparison, an electrostatic image developer containing an electrostatic image developing toner that suppresses poor cleaning under both low temperature and low humidity environments and high temperature and high humidity environments is provided.

According to the invention according to <10>, in a toner for developing an electrostatic image having a Ti content of less than 0.05 ppm or more than 18 ppm, the toner for developing an electrostatic image has a toner particle and an external additive containing silica particles. In comparison, a toner cartridge containing toner for developing an electrostatic image that suppresses cleaning failures in both a low-temperature, low-humidity environment and a high-temperature, high-humidity environment is provided.

According to the invention according to <11>, in the toner for developing an electrostatic image having a Ti content of less than 0.05 ppm or more than 18 ppm, the toner for developing an electrostatic image has a toner particle and an external additive containing silica particles. In comparison, a process cartridge is provided in which an electrostatic image developer containing an electrostatic image developing toner that suppresses cleaning failures in both a low temperature, low humidity environment and a high temperature and high humidity environment is applied.

According to the invention according to <12>, in the toner for developing an electrostatic image having a Ti content of less than 0.05 ppm or more than 18 ppm, the toner for developing an electrostatic image has a toner particle and an external additive containing silica particles. In comparison, an image forming apparatus is provided that uses an electrostatic image developer containing an electrostatic image developing toner that suppresses cleaning defects in both low temperature and low humidity environments and high temperature and high humidity environments.

According to the invention according to <13>, in the toner for developing an electrostatic image having a Ti content of less than 0.05 ppm or more than 18 ppm, the toner for developing an electrostatic image has a toner particle and an external additive containing silica particles. In comparison, there is provided an image forming method using an electrostatic image developer containing an electrostatic image developing toner that suppresses cleaning defects in both low temperature and low humidity environments and high temperature and high humidity environments.

1 is a schematic configuration diagram showing an example of an image forming apparatus according to an embodiment. FIG. 2 is a schematic configuration diagram showing an example of a process cartridge that is attached to and detached from the image forming apparatus according to the present embodiment.

EMBODIMENT OF THE INVENTION Below, embodiment which is an example of this invention is described. These descriptions and examples are illustrative of the embodiments and do not limit the scope of the embodiments.

In this specification, a numerical range indicated using "-" indicates a range that includes the numerical values written before and after "-" as the minimum and maximum values, respectively.

In the numerical ranges described step by step in this specification, the upper limit value or lower limit value described in one numerical range may be replaced with the upper limit value or lower limit value of another numerical range described step by step. good. Further, in the numerical ranges described in this specification, the upper limit or lower limit of the numerical range may be replaced with the value shown in the Examples.

In this specification, the term "process" is used not only to refer to an independent process, but also to include any process that is not clearly distinguished from other processes as long as the intended purpose of the process is achieved. .

When embodiments are described in this specification with reference to drawings, the configuration of the embodiments is not limited to the configuration shown in the drawings. Furthermore, the sizes of the members in each figure are conceptual, and the relative size relationships between the members are not limited thereto.

In this specification, each component may contain multiple types of corresponding substances. In this specification, when referring to the amount of each component in a composition, if there are multiple types of substances corresponding to each component in the composition, unless otherwise specified, the multiple types present in the composition means the total amount of substances.

In this specification, each component may include a plurality of types of particles. When a plurality of types of particles corresponding to each component are present in the composition, the particle diameter of each component means a value for a mixture of the plurality of types of particles present in the composition, unless otherwise specified.

In this specification, "toner for developing an electrostatic image" is also simply referred to as "toner", and "electrostatic image developer" is also simply referred to as "developer".

<Toner for electrostatic image development>
The toner according to the present embodiment includes toner particles and an external additive containing silica particles, and has a Ti content of 0.05 ppm or more and 18 ppm or less.
The toner according to the present embodiment can be used in a low-temperature, low-humidity (e.g., 10° C. and 15% humidity) environment, compared to cases where the Ti content (that is, the content of Ti element in the entire toner) is less than 0.05 ppm or more than 18 ppm. Poor cleaning is suppressed under any environment including high temperature and high humidity (for example, temperature of 30° C. and humidity of 85%). Although the reason is not certain, it is assumed as follows.

When a toner containing toner particles and an external additive containing silica particles is applied to a blade cleaning type image forming apparatus, some of the silica particles are released from the toner particles and supplied to the contact area between the cleaning blade and the image carrier. be done. A portion of the silica particles supplied to the contact portion aggregate by forming aggregates (hereinafter also referred to as "external addition dam") due to the pressure from the cleaning blade, thereby removing untransferred toner, etc. on the image carrier. Block it and collect it. On the other hand, another part of the silica particles supplied to the contact portion appropriately passes between the cleaning blade and the image holder, thereby stabilizing the posture of the cleaning blade.

However, especially when images with low image density are formed for a long period of time in a high temperature and high humidity environment, the toner in the developing means is rarely replaced and the external additives strongly adhere to the toner particles, making it difficult for the silica particles to be released. The amount of silica particles supplied to the contact portion may decrease. When the amount of silica particles supplied to the contact portion decreases, it becomes difficult to form external additive dams, which may result in poor cleaning, and color streaks may occur in the resulting image due to poor cleaning.

On the other hand, in this embodiment, the Ti element is contained in a range of 0.05 ppm or more and 18 ppm or less. Therefore, compared to when the Ti content is less than 0.05 ppm, electrostatic repulsion is more likely to occur due to the difference in the charge series between the Si element and the Ti element, and the silica particles are more likely to be released from the toner particles. Conceivable. Since silica particles are easily released from toner particles, even if images with low image density are formed for a long period of time in a high temperature and high humidity environment, silica particles are appropriately supplied to the contact area, so external additives can be used. It is presumed that dams are likely to be formed and cleaning defects are suppressed. By suppressing cleaning defects, color streaks caused by poor cleaning can be suppressed even when images with low image density are formed for a long period of time (for example, over 10,000 sheets in a row) in a high temperature, high humidity environment. High-quality images are provided over a long period of time.

Furthermore, in this embodiment, since the Ti content is 0.05 ppm or more and 18 ppm or less, the amount of silica particles released is smaller even when an image is formed in a low temperature and low humidity environment compared to a case where the Ti content exceeds 18 ppm. It is thought that it is unlikely to become excessive. In addition, since the amount of silica particles released is less likely to become excessive, the instability of the cleaning blade's posture due to excessive silica particles slipping between the cleaning blade and the image holder is suppressed, and the resulting cleaning defects are suppressed. It is assumed that
For the above reasons, it is presumed that the toner of the present embodiment suppresses cleaning defects in both low temperature and low humidity environments and high temperature and high humidity environments.

Details of the toner according to this embodiment will be described below.

The toner according to this embodiment includes toner particles and an external additive.
The toner according to the present embodiment has a Ti content of 0.05 ppm or more and 18 ppm or less.
Below, we will first explain the Ti content etc. of toner.

(Ti content, etc.)
The Ti content is 0.05 ppm or more and 18 ppm or less, preferably 0.1 ppm or more and 15 ppm or less, and more preferably 0.15 ppm or more and 15 ppm or less.

Here, the above Ti content is a value determined by quantitatively analyzing the fluorescent X-ray intensity as follows.
Specifically, first, using 200 mg of a mixture of polyester resin and titanium oxide in which the concentration of Ti element relative to the entire mixture is known, a pellet-shaped sample is produced using an IR tablet molding machine with a diameter of 13 mm. The mass of the obtained pellet-shaped sample is accurately weighed, and the intensity of the peak derived from the Ti element is determined by measuring the fluorescent X-ray intensity. Similarly, pellet-type samples with different concentrations of titanium oxide are weighed accurately, fluorescent X-ray intensity measurements are performed to determine the intensity of the peak derived from the Ti element, and a calibration curve is created from these results.
On the other hand, for the toner to be measured, a pellet-shaped sample was prepared, the mass was accurately weighed, and the fluorescent X-ray intensity was measured. Using the above calibration curve, the Ti content in the toner sample to be measured was determined. Perform quantitative analysis.
The Si content (that is, the content of Si element in the entire toner), which will be described later, is also determined by the same method as the Ti content described above (however, silica is used instead of titanium oxide).
Note that both the Ti content and the Si content are based on mass.

The means for setting the Ti content within the above range is not particularly limited, and the Ti element may be contained inside the toner particles, or the Ti element may be contained outside the toner particles (external additives, etc.). Often, the toner particles may contain Ti element both inside and outside.
Specifically, as a means for setting the Ti content within the above range, for example, Ti-containing particles (that is, particles containing the Ti element) are added to at least one of the toner particles and the external additive so that the Ti content falls within the above range. One way to do this is to include it. The Ti-containing particles may be contained within the toner particles, may be contained in the external additive, or may be contained in both the toner particles and the external additive, but at least the Ti-containing particles are contained in the external additive. Preferably included.

By containing the Ti element inside the toner particles, preferably near the surface layer of the toner, the silica particles are caused by electrostatic repulsion between the Ti element inside the toner particles and the silica particles contained in the external additive. It is thought that it becomes easier to release from the toner particles.
In addition, by using Ti-containing particles as an external additive, the Ti-containing particles, which have a higher affinity with toner particles than silica particles, are more likely to be embedded in the surface of toner particles, and the toner particles in which the Ti-containing particles are embedded can be It is thought that the electrostatic repulsion between the surface and the silica particles contained in the external additive makes it easier for the silica particles to separate from the toner particles.

-Ti-containing particles-
The Ti-containing particles are not particularly limited as long as they contain the Ti element, and include, for example, titanium oxide particles, titanium carbide particles, titanates (magnesium salts, calcium salts, strontium salts, barium salts, etc.). Examples include particles.
Specific examples of Ti-containing particles include titanium oxide particles such as TiO ₂ (titanium oxide) particles and TiO(OH) ₂ (metatanic acid) particles; titanium carbide particles such as TiC (titanium carbide) particles; CaTiO ₃ Titanate particles such as (calcium titanate) particles and SrTiO ₃ (strontium titanate) particles; composite particles such as silica-titania composite oxide particles; and the like.
Among the Ti-containing particles, titanium oxide particles, metatitanic acid particles, and strontium titanate particles are preferred, and titanium oxide particles are more preferred.

The number average particle diameter of the Ti-containing particles is not particularly limited, and may be, for example, in the range of 10 nm or more and 150 nm or less, preferably in the range of 15 nm or more and 100 nm or less, and more preferably in the range of 15 nm or more and 80 nm or less.

The ratio of Ti content to Si content (Ti content/Si content) is preferably 2×10 ⁻⁶ or more and 2×10 −2 or less, and 3×10 ⁻² from the viewpoint of suppressing cleaning defects ^. It is more preferably ⁶ or more and 1×10 ⁻² or less, even more preferably 5×10 ⁻⁶ or more and 1×10 ⁻² or less, and 5×10 ⁻⁶ or more and 8×10 ⁻⁴ or less. Particularly preferred.
The toner particles and external additives will be explained below.

(toner particles)
The toner particles include, for example, a binder resin, and if necessary, a colorant, a release agent, and other additives.

-Binder resin-
Examples of the binder resin include styrenes (such as styrene, parachlorostyrene, α-methylstyrene, etc.), (meth)acrylic esters (such as methyl acrylate, ethyl acrylate, n-propyl acrylate, and acrylic acid). n-butyl, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, etc.), ethylenically unsaturated nitriles (for example, acrylonitrile, (methacrylonitrile, etc.), vinyl ethers (e.g. vinyl methyl ether, vinyl isobutyl ether, etc.), vinyl ketones (vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone, etc.), olefins (e.g. ethylene, propylene, butadiene, etc.), etc. Examples include vinyl resins consisting of a homopolymer of these monomers or a copolymer of a combination of two or more of these monomers.
Examples of the binder resin include non-vinyl resins such as epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, and modified rosins, mixtures of these and the above-mentioned vinyl resins, or mixtures thereof. Also included are graft polymers obtained by polymerizing vinyl monomers in coexistence.
These binder resins may be used alone or in combination of two or more.

As the binder resin, polyester resin is suitable.
Examples of the polyester resin include known amorphous polyester resins. As the polyester resin, a crystalline polyester resin may be used in combination with an amorphous polyester resin. However, the content of the crystalline polyester resin is preferably 2% by mass or more and 40% by mass or less (preferably 2% by mass or more and 20% by mass or less) based on the total binder resin.

Note that the "crystallinity" of a resin refers to having a clear endothermic peak in differential scanning calorimetry (DSC) rather than a stepwise change in endothermic amount. /min) indicates that the half width of the endothermic peak is within 10°C.
On the other hand, the term "amorphous" of a resin means that the half-width exceeds 10°C, that it exhibits a stepwise change in endothermic amount, or that no clear endothermic peak is observed.

-Amorphous polyester resin Examples of the amorphous polyester resin include condensation polymers of polyhydric carboxylic acids and polyhydric alcohols. Note that as the amorphous polyester resin, a commercially available product or a synthesized one may be used.

Examples of polycarboxylic acids include aliphatic dicarboxylic acids (eg, oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, alkenylsuccinic acid, adipic acid, sebacic acid, etc.) , alicyclic dicarboxylic acids (e.g., cyclohexanedicarboxylic acid, etc.), aromatic dicarboxylic acids (e.g., terephthalic acid, isophthalic acid, phthalic acid, naphthalene dicarboxylic acid, etc.), anhydrides thereof, or lower grades thereof (e.g., carbon atoms with 1 or more carbon atoms). 5 or less) alkyl esters. Among these, as the polyhydric carboxylic acid, for example, aromatic dicarboxylic acids are preferable.
The polyvalent carboxylic acid may be a dicarboxylic acid and a trivalent or higher carboxylic acid having a crosslinked structure or a branched structure. Examples of trivalent or higher carboxylic acids include trimellitic acid, pyromellitic acid, anhydrides thereof, and lower (for example, carbon atoms of 1 or more and 5 or less) alkyl esters thereof.
One type of polyhydric carboxylic acid may be used alone, or two or more types may be used in combination.

Examples of polyhydric alcohols include aliphatic diols (e.g., ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, neopentyl glycol, etc.), alicyclic diols (e.g., cyclohexanediol, cyclohexane) dimethanol, hydrogenated bisphenol A, etc.), aromatic diols (eg, ethylene oxide adduct of bisphenol A, propylene oxide adduct of bisphenol A, etc.). Among these, as the polyhydric alcohol, for example, aromatic diols and alicyclic diols are preferable, and aromatic diols are more preferable.
As the polyhydric alcohol, a trivalent or higher polyhydric alcohol having a crosslinked structure or a branched structure may be used together with the diol. Examples of the trivalent or higher polyhydric alcohol include glycerin, trimethylolpropane, and pentaerythritol.
One type of polyhydric alcohol may be used alone, or two or more types may be used in combination.

The glass transition temperature (Tg) of the amorphous polyester resin is preferably 50°C or more and 80°C or less, more preferably 50°C or more and 65°C or less.
The glass transition temperature is determined from the DSC curve obtained by differential scanning calorimetry (DSC), and more specifically, it is described in the method for determining the glass transition temperature of JIS K 7121-1987 "Method for measuring the transition temperature of plastics". It is determined by the "extrapolated glass transition start temperature".

The weight average molecular weight (Mw) of the amorphous polyester resin is preferably 5,000 or more and 1,000,000 or less, more preferably 7,000 or more and 500,000 or less.
The number average molecular weight (Mn) of the amorphous polyester resin is preferably 2,000 or more and 100,000 or less.
The molecular weight distribution Mw/Mn of the amorphous polyester resin is preferably 1.5 or more and 100 or less, more preferably 2 or more and 60 or less.
Note that the weight average molecular weight and number average molecular weight are measured by gel permeation chromatography (GPC). Molecular weight measurement by GPC is performed using a Tosoh GPC/HLC-8120GPC as a measurement device, a Tosoh column/TSKgel SuperHM-M (15 cm), and a THF solvent. The weight average molecular weight and number average molecular weight are calculated from the measurement results using a molecular weight calibration curve prepared using a monodisperse polystyrene standard sample.

Amorphous polyester resin can be obtained by a well-known manufacturing method. Specifically, it can be obtained, for example, by a method in which the polymerization temperature is set at 180° C. or more and 230° C. or less, the pressure inside the reaction system is reduced as necessary, and the reaction is carried out while removing water and alcohol generated during condensation.
In addition, when the raw material monomers are not dissolved or compatible at the reaction temperature, a high boiling point solvent may be added as a solubilizing agent to dissolve them. In this case, the polycondensation reaction is carried out while distilling off the solubilizing agent. If there are monomers with poor compatibility, it is best to condense the monomer with poor compatibility and the acid or alcohol to be polycondensed in advance, and then polycondense them together with the main component. .

-Crystalline polyester resin Examples of crystalline polyester resins include polycondensates of polyhydric carboxylic acids and polyhydric alcohols. Note that as the crystalline polyester resin, a commercially available product or a synthesized product may be used.
Here, the crystalline polyester resin is preferably a polycondensate using a polymerizable monomer having a linear aliphatic group rather than a polymerizable monomer having an aromatic group, since the crystalline polyester resin easily forms a crystal structure.

Examples of polyhydric carboxylic acids include aliphatic dicarboxylic acids (for example, oxalic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid) acids, 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, etc.), aromatic dicarboxylic acids (such as phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid) dibasic acids such as acids), anhydrides thereof, and lower (for example, carbon atoms of 1 or more and 5 or less) alkyl esters thereof.
The polyvalent carboxylic acid may be a dicarboxylic acid and a trivalent or higher carboxylic acid having a crosslinked structure or a branched structure. Examples of trivalent carboxylic acids include aromatic carboxylic acids (for example, 1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, etc.); Examples include anhydrides and lower (for example, carbon atoms of 1 to 5) alkyl esters thereof.
As the polycarboxylic acid, a dicarboxylic acid having a sulfonic acid group or a dicarboxylic acid having an ethylenic double bond may be used in combination with these dicarboxylic acids.
One type of polyhydric carboxylic acid may be used alone, or two or more types may be used in combination.

Examples of the polyhydric alcohol include aliphatic diols (for example, linear aliphatic diols in which the number of carbon atoms in the main chain portion is 7 or more and 20 or less). Examples of aliphatic diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8- Octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18- Examples include octadecanediol and 1,14-eicosandecanediol. Among these, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferred as the aliphatic diol.
As the polyhydric alcohol, a trihydric or higher alcohol having a crosslinked structure or a branched structure may be used in combination with the diol. Examples of trihydric or higher alcohols include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, and the like.
One type of polyhydric alcohol may be used alone, or two or more types may be used in combination.

Here, the content of aliphatic diol in the polyhydric alcohol is preferably 80 mol% or more, preferably 90 mol% or more.

The melting temperature of the crystalline polyester resin is preferably 50°C or more and 100°C or less, more preferably 55°C or more and 90°C or less, and even more preferably 60°C or more and 85°C or less.
The melting temperature is determined from the DSC curve obtained by differential scanning calorimetry (DSC) using the "melting peak temperature" described in the method for determining the melting temperature of JIS K7121-1987 "Method for measuring transition temperature of plastics".

The weight average molecular weight (Mw) of the crystalline polyester resin is preferably 6,000 or more and 35,000 or less.

Crystalline polyester resins can be obtained, for example, by well-known manufacturing methods in the same manner as amorphous polyester resins.

The binder resin preferably does not contain the Ti element. By using a binder resin that does not contain the Ti element, it becomes easier to control the Ti content within the above range.
Examples of the binder resin that does not contain the Ti element include resins that are composed of monomer components that do not contain the Ti element and that are synthesized without using a catalyst that contains the Ti element.

The content of the binder resin is, for example, preferably 40% by mass or more and 95% by mass or less, more preferably 50% by mass or more and 90% by mass or less, and 60% by mass or more and 85% by mass or less, based on the entire toner particles. More preferred.

-Coloring agent-
Examples of colorants include carbon black, chrome yellow, Hansa yellow, benzidine yellow, suren yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, Vulcan orange, watch young red, permanent red, brilliant carmine 3B, and brilliant. Carmine 6B, DuPont Oil Red, Pyrazolone Red, Lysole Red, Rhodamine B Lake, Lake Red C, Pigment Red, Rose Bengal, Aniline Blue, Ultramarine Blue, Calco Oil Blue, Methylene Blue Chloride, Phthalocyanine Blue, Pigment Blue, Phthalocyanine Green, Various pigments such as malachite green oxalate, acridine series, xanthene series, azo series, benzoquinone series, azine series, anthraquinone series, thioindico series, dioxazine series, thiazine series, azomethine series, indico series, phthalocyanine series, aniline black Examples include various types of dyes, such as polymethine, triphenylmethane, diphenylmethane, and thiazole dyes.
One type of colorant may be used alone, or two or more types may be used in combination.

The colorant may be surface-treated if necessary, or may be used in combination with a dispersant. Further, a plurality of colorants may be used in combination.

As the colorant, a colorant that does not contain the Ti element is preferable from the viewpoint of controlling the Ti content within the above range and adjusting the amount of the colorant added depending on the desired color.

The content of the colorant is, for example, preferably 1% by mass or more and 30% by mass or less, more preferably 3% by mass or more and 15% by mass or less, based on the entire toner particles.

-Release agent-
Examples of mold release agents include hydrocarbon waxes; natural waxes such as carnauba wax, rice wax, and candelilla wax; synthetic or mineral/petroleum waxes such as montan wax; and ester waxes such as fatty acid esters and montanic acid esters. ; etc. The mold release agent is not limited to this.

As the mold release agent, from the viewpoint of controlling the Ti content within the above range and adjusting the amount of the mold release agent added according to the desired mold release effect, a mold release agent that does not contain the Ti element is preferable.

The melting temperature of the mold release agent is preferably 50°C or more and 110°C or less, more preferably 60°C or more and 100°C or less.
The melting temperature is determined from the DSC curve obtained by differential scanning calorimetry (DSC) using the "melting peak temperature" described in the method for determining the melting temperature of JIS K 7121-1987 "Method for measuring transition temperature of plastics". .

The content of the release agent is, for example, preferably 1% by mass or more and 20% by mass or less, and more preferably 5% by mass or more and 15% by mass or less, based on the entire toner particles.

-Other additives-
Examples of other additives include well-known additives such as magnetic substances, charge control agents, and inorganic powders. These additives are included in the toner particles as internal additives.

As described above, the Ti content may be adjusted within the above range by including Ti element inside the toner particles, preferably near the surface layer of the toner. In that case, as described above, Ti-containing particles may be used as an internal additive.
When using Ti-containing particles as an internal additive, the amount of Ti-containing particles added is not limited as long as the Ti content is within the above range.

-Characteristics of toner particles, etc.-
The toner particles may be toner particles with a single-layer structure, or may be toner particles with a so-called core-shell structure composed of a core part (core particle) and a coating layer (shell layer) covering the core part. It's okay.
Here, toner particles with a core-shell structure include, for example, a core including a binder resin and other additives such as a colorant and a release agent as necessary, and a binder resin. It is preferable that the cover layer is composed of a coating layer composed of

The volume average particle diameter (D50v) of the toner particles is preferably 2 μm or more and 10 μm or less, more preferably 4 μm or more and 9 μm or less, and even more preferably 4 μm or more and 8 μm or less.

The various average particle diameters and various particle size distribution indices of toner particles were measured using Coulter Multisizer II (manufactured by Beckman Coulter), and the electrolyte was measured using ISOTON-II (manufactured by Beckman Coulter). Ru.
In the measurement, 0.5 mg or more and 50 mg or less of the measurement sample is added to 2 ml of a 5% aqueous solution of a surfactant (preferably sodium alkylbenzenesulfonate) as a dispersant. This is added to 100 ml or more and 150 ml or less of an electrolytic solution.
The electrolyte in which the sample was suspended was dispersed for 1 minute using an ultrasonic disperser, and the particle size distribution of particles in the range of 2 μm to 60 μm was determined using a Coulter Multisizer II with an aperture of 100 μm. Measure. Note that the number of particles to be sampled is 50,000.
For the particle size range (channel) divided based on the measured particle size distribution, draw a cumulative distribution of volume and number from the small diameter side, and calculate the particle size that gives a cumulative 16% as the volume particle size D16v and the number particle size. D16p, the particle size that gives a cumulative 50% is defined as a volume average particle size D50v, the cumulative number average particle size D50p, and the particle size that gives a cumulative 84% as a volume particle size D84v, and a number particle size D84p.
Using these, the volume particle size distribution index (GSDv) is calculated as (D84v/D16v) ^1/2 and the number particle size distribution index (GSDp) is calculated as (D84p/D16p) ^1/2 .

The average circularity of the toner particles is preferably 0.93 or more and 1.00 or less, more preferably 0.93 or more and 0.99 or less, and even more preferably 0.95 or more and 0.98 or less.

The average circularity of the toner particles is determined by (circle equivalent perimeter)/(perimeter) [(perimeter of a circle having the same projected area as the particle image)/(perimeter of the projected particle image)]. Specifically, it is a value measured by the following method.
First, toner particles to be measured are collected by suction, formed into a flat flow, and instantaneously flashed with a strobe to capture a still image of the particles.The flow-type particle image analyzer (Sysmex Corporation) Calculated using FPIA-3000 (manufactured by Co., Ltd.). The number of samples to be used when determining the average circularity is 3,500.
If the toner has an external additive, the toner (developer) to be measured is dispersed in water containing a surfactant, and then subjected to ultrasonic treatment to obtain toner particles from which the external additive has been removed. .

The toner particles preferably have a volume average particle diameter of 4 μm or more and 9 μm or less, and an average circularity of 0.93 or more and 0.99 or less, from the viewpoint of charging uniformity. Note that when using toner particles whose volume average particle size and average circularity are within the above ranges, cleaning may be difficult due to the high uniformity of particle size and shape. Also, in this embodiment, cleaning defects are suppressed because the Ti content is within the above range.

(external additive)
The external additive contains at least silica particles, and may contain other external additives as necessary.
The external additive preferably contains silica particles having a BET specific surface area of 100 m ² /g or more (hereinafter also referred to as "first silica particles").
Further, the external additive may include, as silica particles, silica particles having a BET specific surface area of less than 100 m ² /g (hereinafter also referred to as "second silica particles") in addition to the first silica particles.

As described above, the Ti content may be adjusted to the above range by including Ti element outside the toner particles. That is, for the purpose of adjusting the Ti content within the above range, the external additive may contain Ti element. In that case, as described above, Ti-containing particles may be used as an external additive.
When using Ti-containing particles as an external additive, the amount of Ti-containing particles added is not limited as long as the Ti content is within the above range. Among them,

-First silica particles-
The first silica particles are silica particles having a BET specific surface area of 100 m ² /g or more.
The BET specific surface area of the first silica particles is preferably 100 m ² /g or more and 240 m ² /g or less, more preferably 120 m ² /g or more and 220 m ² /g or less, and further preferably 120 m ² /g or more and 180 m ² /g or less. preferable.

The BET specific surface area of silica particles is measured by a BET multipoint method using nitrogen gas.
The sample to be measured is silica particles that are the material of the toner or silica particles separated from the toner. There are no restrictions on the method for separating silica particles from toner. For example, after applying ultrasound to a dispersion of toner in water containing a surfactant, centrifuging the dispersion at high speed, and storing the supernatant at room temperature (23 ℃±2℃) to obtain silica particles.

The number average particle size (average primary particle size) of the first silica particles is preferably 20 nm or more and 90 nm or less, more preferably 40 nm or more and 80 nm or less, and even more preferably 45 nm or more and 75 nm or less.
When the number average particle size of the first silica particles is within the above range, the first silica particles are less likely to be buried in the toner particles than when the number average particle size of the first silica particles is smaller than the above range. Within the above range, it is easier to control the liberation of the first silica particles within an appropriate range, compared to when it is larger than the above range.

In this embodiment, the particle size (primary particle size) of the first silica particles is the diameter of a circle having the same area as the primary particle image (so-called equivalent circle diameter). The number average particle size of the first silica particles and the proportion of particles with a particle size of 20 nm or more and 90 nm or less are determined by taking an electron microscope image of the toner to which the first silica particles are externally added. This is determined by image analysis of at least 300 particles. The average primary particle size of the first silica particles is a particle size that is cumulatively 50% from the small diameter side in the number-based distribution of primary particle sizes.

Examples of the first silica particles include sol-gel silica particles.
Sol-gel silica particles can be obtained, for example, as follows.
Tetraalkoxysilane is dropped into an alkaline catalyst solution containing an alcohol compound and aqueous ammonia, and the tetraalkoxysilane is hydrolyzed and condensed to obtain a suspension containing sol-gel silica particles. Then, the solvent is removed from the suspension to obtain granules. Next, sol-gel silica particles are obtained by drying the granules.
The number average particle size and particle size distribution of the sol-gel silica particles are controlled by the amount of tetraalkoxysilane added dropwise relative to the amount of the alkaline catalyst solution.

The sol-gel silica particles may be hydrophobic sol-gel silica particles subjected to a hydrophobic surface treatment. The hydrophobizing agent is not particularly limited, but silicon-containing organic compounds are preferred. Examples of silicon-containing organic compounds include alkoxysilane compounds, silazane compounds, and silicone oils. These may be used alone or in combination of two or more.

As the hydrophobizing agent for sol-gel silica particles, silazane compounds (for example, dimethyldisilazane, trimethyldisilazane, tetramethyldisilazane, pentamethyldisilazane, hexamethyldisilazane, etc.) are preferred, and 1,1,1,3 ,3,3-hexamethyldisilazane (HMDS) is particularly preferred.

Even when the sol-gel silica particles are hydrophobic sol-gel silica particles subjected to a hydrophobic surface treatment, the mass reduction rate upon heating is preferably within the above-mentioned range, and the average primary particle diameter is preferably within the above-mentioned range.

The external addition amount of the first silica particles is preferably 0.01% by mass or more and 10% by mass or less, more preferably 0.05% by mass or more and 5% by mass or less, and 0.1% by mass or less, based on the mass of the toner particles. % or more and 2.5% by mass or less is more preferable.

-Second silica particles-
The second silica particles have a BET specific surface area of less than 100 m ² /g.
By using the first silica particles and the second silica particles together as external additives, cleaning defects can be more easily suppressed.

The BET specific surface area of the second silica particles is preferably from 20 m ² /g to 90 m ² /g, more preferably from 20 m ² /g to 85 m ² /g, and from 20 m ² /g to 80 m 2 /g. More preferably, it is ² /g or less.
The number average particle size (average primary particle size) of the second silica particles is preferably 40 nm or more and 200 nm or less, more preferably 50 nm or more and 190 nm or less, and even more preferably 60 nm or more and 180 nm or less.

The surface of the second silica particles is preferably subjected to a hydrophobic treatment. The hydrophobization treatment is performed, for example, by immersing the silica particles in a hydrophobization treatment agent. The hydrophobizing agent is not particularly limited, and examples thereof include silane coupling agents, silicone oils, titanate coupling agents, aluminum coupling agents, and the like. These may be used alone or in combination of two or more.
The amount of the hydrophobizing agent is usually, for example, 1 part by mass or more and 10 parts by mass or less, based on 100 parts by mass of silica particles.

The total content of the first silica particles and the second silica particles is, for example, 80% by mass or more, preferably 90% by mass or more, more preferably 95% by mass, based on the total amount of external additives. % or more

-Other external additives-
Examples of other external additives include inorganic particles other than the silica particles and titanium-containing particles. The inorganic particles include Al ₂ O ₃ , CuO, ZnO, SnO ₂ , CeO ₂ , Fe ₂ O ₃ , MgO, BaO, CaO, K ₂ O, Na ₂ O, ZrO ₂ , CaO・SiO ₂ , Al ₂ O Examples include 3.2SiO ₂ , CaCO ₃ , MgCO ₃ , BaSO _{4 and} MgSO ₄ .

Other external additives include resin particles (resin particles such as polystyrene, polymethyl methacrylate (PMMA), melamine resin, etc.), cleaning active agents (for example, metal salts of higher fatty acids such as zinc stearate, fluorine-based Examples include molecular weight particles).

The total amount of external additives added is, for example, preferably 0.01% by mass or more and 5% by mass or less, more preferably 1.0% by mass or more and 4.0% by mass or less, based on the toner particles.

The total content of external additives contained in the toner is determined by the following measurement method.
After applying ultrasonic waves to a dispersion in which toner is dispersed in water containing a surfactant, the dispersion is centrifuged at high speed, and the supernatant is dried at room temperature (23°C ± 2°C) to obtain external additives. Then, weigh the external additive obtained from the supernatant liquid.

(Toner manufacturing method)
Next, a method for manufacturing toner according to this embodiment will be described.
The toner according to the present embodiment is obtained by externally adding an external additive to the toner particles after manufacturing the toner particles.

The toner particles may be manufactured by either a dry manufacturing method (for example, kneading and pulverizing method, etc.) or a wet manufacturing method (for example, aggregation coalescence method, suspension polymerization method, dissolution suspension method, etc.). There are no particular limitations on the manufacturing method of toner particles, and well-known manufacturing methods may be employed.
Among these, it is preferable to obtain toner particles by an aggregation coalescence method.

Specifically, for example, when toner particles are manufactured by an aggregation coalescence method,
The process of preparing a resin particle dispersion in which resin particles that will become the binder resin are dispersed (resin particle dispersion preparation process), and (in a dispersion liquid), a step of agglomerating resin particles (other particles as necessary) to form agglomerated particles (agglomerated particle formation step), and heating the agglomerated particle dispersion liquid in which the agglomerated particles are dispersed. Toner particles are manufactured through a step of fusing and coalescing the aggregated particles to form toner particles (fusing and coalescing step).

Here, toner particles obtained by the aggregation coalescence method have a narrow particle size distribution and a nearly spherical shape, so they have the advantage of high uniformity of charging, but also have the advantage of high uniformity of particle size and shape. It may be difficult to clean. However, even when toner particles obtained by the aggregation and coalescence method are used, in this embodiment, cleaning defects are suppressed because the Ti content is within the above range.

The details of each step will be explained below.
In the following description, a method for obtaining toner particles containing a colorant and a release agent will be described, but the colorant and release agent are used as necessary. Of course, other additives than the colorant and mold release agent may be used.

-Resin particle dispersion preparation process-
First, together with a resin particle dispersion in which resin particles serving as a binder resin are dispersed, for example, a colorant particle dispersion in which colorant particles are dispersed and a release agent particle dispersion in which release agent particles are dispersed are prepared. do.

Here, the resin particle dispersion liquid is prepared, for example, by dispersing resin particles in a dispersion medium using a surfactant.

Examples of the dispersion medium used in the resin particle dispersion include an aqueous medium.
Examples of the aqueous medium include water such as distilled water and ion-exchanged water, alcohols, and the like. These may be used alone or in combination of two or more.

Examples of the surfactant include anionic surfactants such as sulfate ester salts, sulfonate salts, phosphate esters, and soaps; cationic surfactants such as amine salts and quaternary ammonium salts; polyethylene glycol Examples include nonionic surfactants such as surfactants based on surfactants, alkylphenol ethylene oxide adducts, and polyhydric alcohols. Among these, anionic surfactants and cationic surfactants are particularly mentioned. Nonionic surfactants may be used in combination with anionic surfactants or cationic surfactants.
One type of surfactant may be used alone, or two or more types may be used in combination.

In the resin particle dispersion, methods for dispersing resin particles in a dispersion medium include, for example, general dispersion methods such as a rotary shear type homogenizer, a ball mill with media, a sand mill, and a dyno mill. Further, depending on the type of resin particles, the resin particles may be dispersed in the resin particle dispersion using, for example, a phase inversion emulsification method.
Note that the phase inversion emulsification method involves dissolving the resin to be dispersed in a hydrophobic organic solvent in which the resin is soluble, adding a base to the organic continuous phase (O phase) to neutralize it, and then dissolving it in an aqueous medium. (W phase), the resin is converted from W/O to O/W (so-called phase inversion) to form a discontinuous phase, and the resin is dispersed in the form of particles in an aqueous medium. It is.

The volume average particle diameter of the resin particles dispersed in the resin particle dispersion is, for example, preferably 0.01 μm or more and 1 μm or less, more preferably 0.08 μm or more and 0.8 μm or less, and further preferably 0.1 μm or more and 0.6 μm or less. preferable.
The volume average particle diameter of the resin particles is determined by using the particle size distribution obtained by measurement using a laser diffraction particle size distribution analyzer (for example, LA-700 manufactured by Horiba, Ltd.). , the cumulative distribution is subtracted from the small particle size side for the volume, and the particle size that is cumulatively 50% of all particles is measured as the volume average particle size D50v. Note that the volume average particle diameters of particles in other dispersions are also measured in the same manner.

The content of the resin particles contained in the resin particle dispersion is, for example, preferably 5% by mass or more and 50% by mass or less, and more preferably 10% by mass or more and 40% by mass or less.

Note that, in the same manner as the resin particle dispersion, for example, a colorant particle dispersion and a release agent particle dispersion are also prepared. In other words, regarding the volume average particle size, dispersion medium, dispersion method, and content of particles in the resin particle dispersion, the colorant particles dispersed in the colorant particle dispersion and the release agent particle dispersion The same applies to the releasing agent particles to be dispersed.

-Agglomerated particle formation process-
Next, the colorant particle dispersion and the release agent particle dispersion are mixed together with the resin particle dispersion.
Then, in the mixed dispersion liquid, the resin particles, colorant particles, and release agent particles are heteroagglomerated to form resin particles, colorant particles, and release agent particles having a diameter close to that of the target toner particles. form agglomerated particles containing

Specifically, for example, after adding a flocculant to the mixed dispersion, adjusting the pH of the mixed dispersion to acidic (for example, pH 2 or more and 5 or less), and adding a dispersion stabilizer as necessary, The particles dispersed in the mixed dispersion are agglomerated by heating to a temperature of the glass transition temperature of the resin particles (specifically, for example, the glass transition temperature of the resin particles -30°C or more and the glass transition temperature -10°C or less). , forming agglomerated particles.
In the agglomerated particle forming step, for example, the above-mentioned flocculant is added to the mixed dispersion at room temperature (e.g. 25°C) while stirring with a rotary shear type homogenizer, and the pH of the mixed dispersion is adjusted to acidic (e.g. pH 2 to 5). ), and after adding a dispersion stabilizer if necessary, the above heating may be performed.

Examples of the flocculant include a surfactant having a polarity opposite to that of the surfactant used as a dispersant added to the mixed dispersion, an inorganic metal salt, and a divalent or higher valence metal complex. In particular, when a metal complex is used as the flocculant, the amount of surfactant used is reduced and the charging characteristics are improved.
An additive that forms a complex or similar bond with the metal ion of the flocculant may be used as necessary. A chelating agent is preferably used as this additive.

Examples of inorganic metal salts include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate, and inorganic salts such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. Examples include metal salt polymers.
As the chelating agent, a water-soluble chelating agent may be used. Examples of the chelating agent include oxycarboxylic acids such as tartaric acid, citric acid, and gluconic acid, iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), and ethylenediaminetetraacetic acid (EDTA).
The amount of the chelating agent added is, for example, preferably 0.01 parts by mass or more and 5.0 parts by mass or less, more preferably 0.1 parts by mass or more and less than 3.0 parts by mass, based on 100 parts by mass of the resin particles.

-Fusion/unification process-
Next, the agglomerated particle dispersion liquid in which the agglomerated particles are dispersed is heated, for example, to a temperature higher than the glass transition temperature of the resin particles (for example, a temperature higher than the glass transition temperature of the resin particles by 10 to 30 degrees Celsius), and the agglomerated particles are heated to a temperature higher than the glass transition temperature of the resin particles. fuse and coalesce to form toner particles.

Through the above steps, toner particles are obtained.
Note that after obtaining the aggregated particle dispersion liquid in which aggregated particles are dispersed, the aggregated particle dispersion liquid and the resin particle dispersion liquid in which resin particles are dispersed are further mixed to further coat the surface of the aggregated particles with resin particles. a step of agglomerating so as to adhere to form a second agglomerated particle; heating a second agglomerated particle dispersion in which the second agglomerated particles are dispersed to fuse and coalesce the second agglomerated particles; The toner particles may be manufactured through the steps of forming toner particles having a core/shell structure.

Here, after the fusion/unification step is completed, the toner particles formed in the solution are subjected to a known washing step, solid-liquid separation step, and drying step to obtain dried toner particles.
In the washing step, it is preferable to sufficiently perform displacement washing with ion-exchanged water from the viewpoint of chargeability. Further, the solid-liquid separation step is not particularly limited, but from the viewpoint of productivity, it is preferable to perform suction filtration, pressure filtration, or the like. Further, there is no particular restriction on the drying process, but from the viewpoint of productivity, it is preferable to perform freeze drying, flash drying, fluidized drying, vibrating fluidized drying, or the like.

The toner according to the present embodiment is manufactured, for example, by adding and mixing external additives to the obtained dry toner particles. Mixing may be carried out using, for example, a V-blender, a Henschel mixer, a Loedige mixer, or the like. Furthermore, if necessary, coarse toner particles may be removed using a vibrating sieve, a wind sieve, or the like.

<Electrostatic image developer>
The electrostatic image developer according to this embodiment contains at least the toner according to this embodiment.
The electrostatic image developer according to the present embodiment may be a one-component developer containing only the toner according to the present embodiment, or may be a two-component developer containing the toner and a carrier mixed.

There are no particular limitations on the carrier, and known carriers may be used. Examples of carriers include coated carriers in which the surface of a core material made of magnetic powder is coated with coating resin; magnetic powder-dispersed carriers in which magnetic powder is dispersed and blended in matrix resin; porous magnetic powder impregnated with resin. and resin-impregnated carriers.
The magnetic powder-dispersed carrier and the resin-impregnated carrier may be carriers in which constituent particles of the carrier are used as a core material and coated with a coating resin.

Examples of the magnetic powder include magnetic metals such as iron, nickel, and cobalt, and magnetic oxides such as ferrite and magnetite.

Examples of the coating resin and matrix resin include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic acid ester. Examples include copolymers, straight silicone resins containing organosiloxane bonds or modified products thereof, fluororesins, polyesters, polycarbonates, phenolic resins, and epoxy resins.
Note that the coating resin and the matrix resin may contain other additives such as conductive particles.
Examples of the conductive particles include particles of metals such as gold, silver, and copper, carbon black, titanium oxide, zinc oxide, tin oxide, barium sulfate, aluminum borate, and potassium titanate.

Here, in order to coat the surface of the core material with the coating resin, a method of coating with a coating layer forming solution in which the coating resin and, if necessary, various additives are dissolved in a suitable solvent, etc. can be mentioned. The solvent is not particularly limited and may be selected in consideration of the coating resin to be used, coating suitability, etc.
Specific resin coating methods include a dipping method in which the core material is immersed in a solution for forming a coating layer, a spray method in which the solution for forming a coating layer is sprayed onto the surface of the core material, and a method in which the core material is suspended in fluidized air. Examples include a fluidized bed method in which a coating layer forming solution is sprayed, and a kneader coater method in which a carrier core material and a coating layer forming solution are mixed in a kneader coater and the solvent is removed.

The mixing ratio (mass ratio) of toner and carrier in the two-component developer is preferably toner:carrier = 1:100 to 30:100, more preferably 3:100 to 20:100.

<Image forming apparatus/image forming method>
An image forming apparatus/image forming method according to this embodiment will be described.
The image forming apparatus according to the present embodiment includes an image carrier, a charging means for charging the surface of the image carrier, an electrostatic image forming means for forming an electrostatic charge image on the surface of the charged image carrier, and an electrostatic charge image forming means for forming an electrostatic charge image on the surface of the charged image carrier. a developing means that contains an image developer and develops the electrostatic image formed on the surface of the image carrier as a toner image with the electrostatic charge image developer; A cleaning device having a cleaning blade that cleans the surface of the image carrier, and a fixing device that fixes the toner image transferred to the surface of the recording medium. The electrostatic image developer according to this embodiment is applied as the electrostatic image developer.

The image forming apparatus according to the present embodiment includes a charging process of charging the surface of the image carrier, an electrostatic image forming process of forming an electrostatic charge image on the surface of the charged image carrier, and an electrostatic charge according to the present embodiment. a developing step of developing an electrostatic charge image formed on the surface of the image carrier as a toner image with an image developer; a transfer step of transferring the toner image formed on the surface of the image carrier onto the surface of a recording medium; An image forming method (image forming method according to the present embodiment) including a cleaning step of cleaning the surface of the image carrier with a cleaning blade and a fixing step of fixing the toner image transferred to the surface of the recording medium is carried out. Ru.

The image forming apparatus according to this embodiment is a direct transfer type device that directly transfers a toner image formed on the surface of an image carrier to a recording medium; a toner image formed on the surface of an image carrier is transferred to an intermediate transfer member. Intermediate transfer type device that performs primary transfer on the surface of the image carrier and secondary transfer of the toner image transferred to the surface of the intermediate transfer member onto the surface of the recording medium; after transferring the toner image and before charging, a static eliminating light is applied to the surface of the image carrier. A well-known image forming apparatus, such as an apparatus equipped with a static elimination means that eliminates static electricity by irradiating the image, can be applied.
In the case of an intermediate transfer type device, the transfer means includes, for example, an intermediate transfer body on which a toner image is transferred, and a primary transfer body that primarily transfers a toner image formed on the surface of an image carrier onto the surface of the intermediate transfer body. and a secondary transfer means for secondarily transferring the toner image transferred to the surface of the intermediate transfer member to the surface of the recording medium.

In the image forming apparatus according to the present embodiment, for example, the portion including the developing means may have a cartridge structure (process cartridge) that is detachable from the image forming apparatus. As the process cartridge, for example, a process cartridge including a developing means containing the electrostatic image developer according to the present embodiment is suitably used.

An example of an image forming apparatus according to this embodiment will be shown below, but the present invention is not limited thereto. Note that the main parts shown in the figure will be explained, and the explanation of the others will be omitted.

FIG. 1 is a schematic configuration diagram showing an image forming apparatus according to this embodiment.
The image forming apparatus shown in FIG. It includes fourth image forming units 10Y, 10M, 10C, and 10K (image forming means). These image forming units (hereinafter sometimes simply referred to as "units") 10Y, 10M, 10C, and 10K are arranged in parallel at a predetermined distance from each other in the horizontal direction. Note that these units 10Y, 10M, 10C, and 10K may be process cartridges that are detachable from the image forming apparatus.

Above each unit 10Y, 10M, 10C, and 10K in the drawing, an intermediate transfer belt 20 serving as an intermediate transfer body extends through each unit. The intermediate transfer belt 20 is provided so as to be wound around a drive roll 22 and a support roll 24 that are in contact with the inner surface of the intermediate transfer belt 20, which are arranged spaced apart from each other from left to right in the figure, and are wound around a drive roll 22 and a support roll 24 that are in contact with the inner surface of the intermediate transfer belt 20. It is designed to run in the direction toward unit 10K. Note that a force is applied to the support roll 24 in a direction away from the drive roll 22 by a spring or the like (not shown), and tension is applied to the intermediate transfer belt 20 wound around both of the support rolls 24 . Further, an intermediate transfer body cleaning device 30 is provided on the side surface of the image carrier of the intermediate transfer belt 20, facing the drive roll 22.
In addition, each of the developing devices (developing means) 4Y, 4M, 4C, and 4K of each unit 10Y, 10M, 10C, and 10K has yellow, magenta, cyan, and black toners housed in toner cartridges 8Y, 8M, 8C, and 8K. Toner containing toner of four colors is supplied.

Since the first to fourth units 10Y, 10M, 10C, and 10K have the same configuration, here, the first unit for forming a yellow image disposed on the upstream side in the traveling direction of the intermediate transfer belt 10Y will be explained as a representative. In addition, by attaching reference numerals with magenta (M), cyan (C), and black (K) instead of yellow (Y) to the parts equivalent to the first unit 10Y, the second to fourth units A description of the units 10M, 10C, and 10K will be omitted.

The first unit 10Y has a photoreceptor 1Y that acts as an image carrier. Around the photoreceptor 1Y, there is a charging roll (an example of charging means) 2Y that charges the surface of the photoreceptor 1Y to a predetermined potential, and the charged surface is exposed to a laser beam 3Y based on a color-separated image signal. an exposure device (an example of an electrostatic image forming means) 3, a developing device (an example of a developing means) 4Y, which supplies charged toner to an electrostatic image and develops the electrostatic image; A primary transfer roll 5Y (an example of a primary transfer means) that transfers a toner image onto the intermediate transfer belt 20, and a photoreceptor cleaning device (an example of a cleaning means) 6Y that removes toner remaining on the surface of the photoreceptor 1Y after the primary transfer. are arranged in order.
Note that the primary transfer roll 5Y is disposed inside the intermediate transfer belt 20, and is provided at a position facing the photoreceptor 1Y. Furthermore, a bias power source (not shown) for applying a primary transfer bias is connected to each of the primary transfer rolls 5Y, 5M, 5C, and 5K. Each bias power supply varies the transfer bias applied to each primary transfer roll under control by a control section (not shown).

The operation of forming a yellow image in the first unit 10Y will be described below.
First, prior to operation, the surface of the photoreceptor 1Y is charged to a potential of -600V to -800V by the charging roll 2Y.
The photoreceptor 1Y is formed by laminating a photosensitive layer on a conductive base (for example, volume resistivity at 20° C.: 1×10 ⁻⁶ Ωcm or less). This photosensitive layer normally has a high resistance (resistance of general resin), but when it is irradiated with the laser beam 3Y, it has a property that the specific resistance of the portion irradiated with the laser beam changes. Therefore, a laser beam 3Y is outputted onto the surface of the charged photoreceptor 1Y via the exposure device 3 in accordance with image data for yellow sent from a control section (not shown). The laser beam 3Y is irradiated onto the photosensitive layer on the surface of the photoreceptor 1Y, thereby forming an electrostatic charge image of a yellow image pattern on the surface of the photoreceptor 1Y.

An electrostatic charge image is an image formed on the surface of the photoconductor 1Y by electrical charging, and the laser beam 3Y reduces the specific resistance of the irradiated part of the photoconductor layer, causing the charged charges on the surface of the photoconductor 1Y to flow. , on the other hand, is a so-called negative latent image formed by residual charges in areas not irradiated with the laser beam 3Y.
The electrostatic charge image formed on the photoreceptor 1Y is rotated to a predetermined development position as the photoreceptor 1Y travels. At this developing position, the electrostatic charge image on the photoreceptor 1Y is converted into a visible image (developed image) as a toner image by the developing device 4Y.

The developing device 4Y contains, for example, an electrostatic image developer containing at least yellow toner and carrier. The yellow toner is triboelectrically charged by being stirred inside the developing device 4Y, and has an electric charge of the same polarity (negative polarity) as the electric charge charged on the photoreceptor 1Y, and is transferred to the developer roll (developer holder). An example) is held on top. Then, as the surface of the photoconductor 1Y passes through the developing device 4Y, yellow toner electrostatically adheres to the latent image area on the surface of the photoconductor 1Y from which the static electricity has been removed, and the latent image is developed with the yellow toner. . The photoconductor 1Y on which the yellow toner image has been formed continues to travel at a predetermined speed, and the toner image developed on the photoconductor 1Y is conveyed to a predetermined primary transfer position.

When the yellow toner image on the photoconductor 1Y is conveyed to the primary transfer position, a primary transfer bias is applied to the primary transfer roll 5Y, and an electrostatic force from the photoconductor 1Y toward the primary transfer roll 5Y is applied to the toner image. The toner image on body 1Y is transferred onto intermediate transfer belt 20. The transfer bias applied at this time has a (+) polarity opposite to the toner polarity (-), and is controlled to +10 μA by a control section (not shown) in the first unit 10Y, for example.
On the other hand, the toner remaining on the photoreceptor 1Y is removed and collected by the photoreceptor cleaning device 6Y.

Further, the primary transfer bias applied to the primary transfer rolls 5M, 5C, and 5K after the second unit 10M is also controlled in accordance with the first unit.
In this way, the intermediate transfer belt 20 to which the yellow toner image has been transferred in the first unit 10Y is sequentially conveyed through the second to fourth units 10M, 10C, and 10K, and the toner images of each color are superimposed and multi-transferred. Ru.

The intermediate transfer belt 20 on which toner images of four colors are multiple-transferred through the first to fourth units is disposed on the image holding surface side of the intermediate transfer belt 20 and a support roll 24 in contact with the inner surface of the intermediate transfer belt. A secondary transfer unit is formed of a secondary transfer roll (an example of secondary transfer means) 26. On the other hand, recording paper (an example of a recording medium) P is fed via a supply mechanism to the gap where the secondary transfer roll 26 and the intermediate transfer belt 20 are in contact with each other at a predetermined timing, and the secondary transfer bias is applied to the support roll. 24. The transfer bias applied at this time has the same polarity (-) as the polarity (-) of the toner, and an electrostatic force from the intermediate transfer belt 20 toward the recording paper P is applied to the toner image, and the transfer bias is applied on the intermediate transfer belt 20. The toner image is transferred onto the recording paper P. Note that the secondary transfer bias at this time is determined according to the resistance detected by a resistance detection means (not shown) that detects the resistance of the secondary transfer portion, and is voltage controlled.

Thereafter, the recording paper P is fed into a pressure contact portion (nip portion) between a pair of fixing rolls in a fixing device (an example of fixing means) 28, and the toner image is fixed onto the recording paper P, forming a fixed image.

Examples of the recording paper P on which the toner image is transferred include plain paper used in electrophotographic copying machines, printers, and the like. In addition to the recording paper P, examples of the recording medium include OHP sheets and the like.
In order to further improve the smoothness of the image surface after fixing, it is preferable that the surface of the recording paper P is also smooth. For example, coated paper in which the surface of plain paper is coated with resin, etc., art paper for printing, etc. are preferably used. be done.

The recording paper P on which the color image has been fixed is carried out toward the discharge section, and the series of color image forming operations is completed.

<Process cartridge/toner cartridge>
A process cartridge according to this embodiment will be described.
The process cartridge according to the present embodiment contains the electrostatic charge image developer according to the present embodiment, and is a developing means for developing the electrostatic charge image formed on the surface of the image carrier as a toner image using the electrostatic charge image developer. This is a process cartridge that can be attached to and removed from an image forming apparatus.

Note that the process cartridge according to the present embodiment is not limited to the above configuration, and includes a developing device and other means, as necessary, such as an image carrier, a charging means, an electrostatic image forming means, and a transfer means. The configuration may include at least one selected from the following.

An example of the process cartridge according to this embodiment will be shown below, but the present invention is not limited thereto. Note that the main parts shown in the figure will be explained, and the explanation of the others will be omitted.

FIG. 2 is a schematic configuration diagram showing the process cartridge according to this embodiment.
The process cartridge 200 shown in FIG. 2 is equipped with a photoconductor 107 (an example of an image holder) and the periphery of the photoconductor 107, for example, by a housing 117 equipped with a mounting rail 116 and an opening 118 for exposure. The charging roll 108 (an example of a charging means), the developing device 111 (an example of a developing means), and the photoreceptor cleaning device 113 (an example of a cleaning means) are integrally combined and held, and are formed into a cartridge. There is.
In FIG. 2, 109 is an exposure device (an example of an electrostatic image forming means), 112 is a transfer device (an example of a transfer means), 115 is a fixing device (an example of a fixing means), and 300 is a recording paper (an example of a recording medium). example).

Next, a toner cartridge according to this embodiment will be described.
The toner cartridge according to this embodiment is a toner cartridge that accommodates the toner according to this embodiment and is detachable from an image forming apparatus. The toner cartridge accommodates replenishment toner to be supplied to a developing means provided within the image forming apparatus.

The image forming apparatus shown in FIG. 1 is an image forming apparatus having a configuration in which toner cartridges 8Y, 8M, 8C, and 8K are attached and detached, and the developing devices 4Y, 4M, 4C, and 4K are the respective developing devices (color ) is connected to a toner cartridge that is compatible with the toner cartridge by a toner supply pipe (not shown). Further, when the amount of toner contained in the toner cartridge becomes low, the toner cartridge is replaced.

Hereinafter, embodiments of the invention will be described in detail with reference to Examples, but the embodiments of the invention are not limited to these Examples at all. In the following description, "parts" are based on mass unless otherwise specified.

<Example 1>
(Preparation of amorphous polyester resin dispersion (A1))
・Terephthalic acid: 70 parts ・Fumaric acid: 30 parts ・Ethylene glycol: 44 parts ・1,5-pentanediol: 47 parts

The above materials were charged into a 5 liter flask equipped with a stirring device, a nitrogen inlet tube, a temperature sensor, and a rectification column, and the temperature was raised to 220°C over 1 hour under a nitrogen gas flow. 1 part of dibutyltin oxide was added to 100 parts in total. The temperature was raised to 240° C. over 0.5 hours while the water produced was distilled off, and the dehydration condensation reaction was continued at this temperature for 1 hour, and then the reaction product was cooled. In this way, a polyester resin having a weight average molecular weight of 95,000 and a glass transition temperature of 62°C was synthesized.

40 parts of ethyl acetate and 25 parts of 2-butanol were put into a container equipped with temperature control means and nitrogen purging means to form a mixed solvent, and then 100 parts of polyester resin was gradually added and dissolved. % ammonia aqueous solution (equivalent to 3 times the molar amount relative to the acid value of the resin) and stirred for 30 minutes. Next, the inside of the container was purged with dry nitrogen, the temperature was maintained at 40° C., and 400 parts of ion-exchanged water was added dropwise at a rate of 2 parts/min while stirring the mixed solution to effect emulsification. After the dropwise addition was completed, the emulsion was returned to 25° C. to obtain a resin particle dispersion in which resin particles having a volume average particle diameter of 200 nm were dispersed. Ion-exchanged water was added to the resin particle dispersion to adjust the solid content to 20% by mass to obtain an amorphous polyester resin dispersion (A1).

(Preparation of crystalline polyester resin dispersion (B1))
・Dimethyl sebacate: 97 parts ・Dimethyl isophthalate-5-sodium sulfonate: 3 parts ・Ethylene glycol: 100 parts ・Dibutyltin oxide (catalyst): 0.3 parts by mass

After putting the above ingredients into a three-necked flask that had been heated and dried, the air inside the container was brought into an inert atmosphere with nitrogen gas by a vacuum operation, and the flask was stirred and refluxed at 180° C. for 5 hours using mechanical stirring. Thereafter, the temperature was gradually raised to 230° C. under reduced pressure and stirred for 2 hours, and when it became viscous, it was air cooled to stop the reaction and crystalline polyester resin B1 was obtained. Molecular weight measurement (polystyrene equivalent) showed that the weight average molecular weight (Mw) of the obtained "crystalline polyester resin B1" was 9700, and the melting temperature was 84°C.

Using 90 parts by mass of the obtained crystalline polyester resin B1, 1.8 parts by mass of the ionic surfactant Neogen RK (Daiichi Kogyo Seiyaku), and 210 parts by mass of ion-exchanged water, the mixture was heated to 100°C. After dispersion using Ultra Turrax T50 manufactured by IKA, dispersion treatment was performed for 1 hour using a pressure discharge type Gorlin homogenizer to obtain a crystalline polyester resin dispersion (B1) having a volume average particle diameter of 200 nm and a solid content of 20 parts by mass. ).

(Preparation of release agent particle dispersion)
・Paraffin wax (HNP-9 manufactured by Nippon Seiro Co., Ltd.): 100 parts ・Anionic surfactant (Neogen RK manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 1 part ・Ion exchange water: 350 parts After mixing and heating to 100°C and dispersing using a homogenizer (Ultra Turrax T50 manufactured by IKA), dispersion treatment was performed using a Manton-Gorlin high-pressure homogenizer (manufactured by Gorlin) to form release agent particles with a volume average particle diameter of 200 nm. A release agent particle dispersion (solid content: 20% by mass) in which was dispersed was obtained.

(Preparation of black colored particle dispersion)
・Carbon black (manufactured by Cabot, Regal 330): 50 parts ・Ionic surfactant Neogen RK (Daiichi Kogyo Seiyaku): 5 parts ・Ion exchange water: 192.9 parts A black colored particle dispersion (solid content concentration: 20% by mass) was prepared by treating the dispersion at 240 MPa for 10 minutes using a chromium-based particle dispersion (solid content concentration: 20% by mass).

(Preparation of toner particles (1))
- Ion exchange water: 200 parts - Amorphous polyester resin dispersion (A1): 150 parts - Crystalline polyester resin dispersion (B1): 10 parts - Black colored particle dispersion: 15 parts - Release agent particle dispersion : 10 parts・Anionic surfactant (TaycaPower): 2.8 parts

The above materials were placed in a round stainless steel flask, and after adjusting the pH to 3.5 by adding 0.1N nitric acid, polyaluminum chloride (PAC, manufactured by Oji Paper Co., Ltd.: 30% powder product)2. An aqueous solution of PAC in which 0 part was dissolved in 30 parts of ion-exchanged water was added. After dispersing at 30° C. using a homogenizer (Ultra Turrax T50 manufactured by IKA), the mixture was heated to 45° C. in a heating oil bath and maintained until the volume average particle diameter became 4.8 μm. Thereafter, 60 parts of amorphous polyester resin particle dispersion (A1) was added and held for 30 minutes. Thereafter, when the volume average particle diameter reached 5.2 μm, 60 parts of the amorphous polyester resin particle dispersion (A1) was further added and maintained for 30 minutes. Subsequently, 20 parts of a 10% by mass NTA (nitrilotriacetic acid) metal salt aqueous solution (Chrest 70: manufactured by Chrest Co., Ltd.) was added, and then the pH was adjusted to 9.0 using a 1N aqueous sodium hydroxide solution. Thereafter, 1.0 part of an anion activator (Tayca Power) was added, and while stirring was continued, the mixture was heated to 85° C. and maintained for 5 hours. Thereafter, the toner particles (1 ) was obtained.

(Preparation of specific silica particles (1))
-Silica particle granulation process-
320 parts of methanol and 72 parts of 10% by mass aqueous ammonia were placed in a glass reaction vessel equipped with a stirrer, a dropping nozzle, and a thermometer and mixed to obtain an alkaline catalyst solution. After adjusting the alkaline catalyst solution to 30° C., 80 parts of tetramethoxysilane (TMOS) and 1.9 parts of 10% by mass aqueous ammonia were added dropwise while stirring the alkaline catalyst solution to obtain a silica particle dispersion. Dripping of TMOS and 10% by mass ammonia water was started at the same time, and the entire amount of each was added dropwise over 5 minutes. Next, the silica particle dispersion was concentrated to a solid content concentration of 40% by mass using a rotary filter (R-Fine manufactured by Kotobuki Kogyo Co., Ltd.). The silica particle dispersion after concentration was used as a silica particle dispersion.

-Surface treatment process of silica particles-
100 parts of hexamethyldisilazane (HMDS) as a hydrophobizing agent was added to 250 parts of the silica particle dispersion, and the mixture was heated to 140°C and reacted for 2 hours. Next, the reacted silica particle dispersion was dried by spray drying to obtain specific silica particles (1).

(Preparation of specific silica particles (2))
Except that 60 parts of tetramethoxysilane (TMOS) and 2.6 parts of 10 mass% ammonia water were dropped instead of 80 parts of tetramethoxysilane (TMOS) and 1.9 parts of 10 mass% ammonia water. The same granulation and surface treatment steps as for silica particles (1) were performed to obtain specific silica particles (2).

(Preparation of specific silica particles (3))
Except that 100 parts of tetramethoxysilane (TMOS) and 1.6 parts of 10 mass% ammonia water were dropped instead of 80 parts of tetramethoxysilane (TMOS) and 1.9 parts of 10 mass% ammonia water. The same granulation and surface treatment steps as for silica particles (1) were performed to obtain specific silica particles (3).

(Preparation of toner (1))
2.0 parts by mass of specific silica particles (1) (first silica particles, BET specific surface area: 130 m ² /g, number average particle diameter: 60 nm) with respect to 100 parts by mass of the obtained toner particles (1). and hydrophobic titanium oxide (manufactured by Nippon Aerosil ^Co. , Ltd., T805, 1.0 parts by mass of a mixture prepared by pre-mixing 0.10% by mass of particles (number average particle diameter: 20 nm) was mixed with a sample mill at 10,000 rpm for 30 seconds. Thereafter, the mixture was sieved using a vibrating sieve with an opening of 45 μm to prepare toner (1). The volume average particle diameter of the obtained toner (1) was 5.9 μm.
Table 1 shows the Ti content and ratio (Ti content/Si content) in the obtained toner (1).

Note that the number average particle diameter of the first silica particles was measured as follows.
Observe 100 fields of view (50,000x) using a scanning electron microscope (SEM: Model S-4700, manufactured by Hitachi, Ltd.), and observe each external additive (if a compound external additive is used, an energy-dispersive type attached to the electron microscope). Using an X-ray analyzer EMAX model 6923H (manufactured by Horiba, Ltd.) at an accelerating voltage of 20 kV, mapping was performed to identify the type of external additive. Average value (obtained by approximating a circle) is obtained by measuring at 1000 locations.

<Example 2>
In the preparation of toner particles (1), when the volume average particle diameter reached 5.2 μm, instead of further adding 60 parts of the amorphous polyester resin particle dispersion (A1), the amorphous polyester resin particle dispersion was added. (A1) 60 parts and hydrophobic titanium oxide (manufactured by Nippon Aerosil Co., Ltd., T805, number average particles) with a concentration of 0.005% by mass based on the resin solid content of 60 parts of the amorphous polyester resin particle dispersion (A1). Toner particles (2) were obtained in the same manner as toner particles (1), except that a mixed solution prepared by preliminarily mixing the toner particles (diameter: 20 nm) was added.

To 100 parts by mass of the obtained toner particles (2), 2.0 parts by mass of specific silica particles (1) (first silica particles, BET specific surface area: 130 m ² /g, number average particle diameter: 60 nm) and 1.0 parts by mass of hydrophobic silica (second silica particles, manufactured by Nippon Aerosil Co., Ltd., RY50, BET specific surface area: 25 m ² /g, number average particle diameter: 140 nm), and 30 parts by mass at 10,000 rpm using a sample mill. Mixed for seconds. Thereafter, the mixture was sieved using a vibrating sieve with an opening of 45 μm to prepare toner (2). The volume average particle diameter of the obtained toner (2) was 5.9 μm.
Table 1 shows the Ti content and ratio (Ti content/Si content) in the obtained toner (2).

<Example 3>
Toner (3) was prepared in the same manner as toner (1) except that the amount of hydrophobic titanium oxide mixed in advance with respect to hydrophobic silica was 0.001% by mass. did. The volume average particle diameter of the obtained toner (3) was 5.9 μm.
Table 1 shows the Ti content and ratio (Ti content/Si content) in the obtained toner (3).

<Example 4>
Toner (4) was prepared in the same manner as toner (1), except that the amount of hydrophobic titanium oxide mixed in advance with respect to hydrophobic silica was 0.185% by mass. did. The volume average particle diameter of the obtained toner (4) was 5.9 μm.
Table 1 shows the Ti content and ratio (Ti content/Si content) in the obtained toner (4).

<Example 5>
In the preparation of toner (1), instead of using 2.0 parts by mass of specific silica particles (1), specific silica particles (2) (first silica particles, BET specific surface area: 160 m ² /g, number average particle diameter: Toner (5) was prepared in the same manner as Toner (1), except that 2.0 parts by mass of (30 nm) was used. The volume average particle diameter of the obtained toner (5) was 5.9 μm.
Table 1 shows the Ti content and ratio (Ti content/Si content) in the obtained toner (5).

<Example 6>
In the preparation of toner (1), instead of using 2.0 parts by mass of specific silica particles (1), specific silica particles (3) (first silica particles, BET specific surface area: 100 m ² /g, number average particle diameter: Toner (6) was prepared in the same manner as Toner (1) except that 2.0 parts by mass of (80 nm) was used. The volume average particle diameter of the obtained toner (6) was 5.9 μm.
Table 1 shows the Ti content and ratio (Ti content/Si content) in the obtained toner (6).

<Example 7>
2.5 parts by mass of specific silica particles (1) (first silica particles, BET specific surface area: 130 m ² /g, number average particle diameter: 60 nm) were added to 100 parts by mass of the obtained toner particles (1). and hydrophobic titanium oxide (manufactured by Nippon Aerosil ^Co. , Ltd., T805, 0.5 parts by mass of a mixture prepared by pre-mixing 0.10% by mass of particles (number average particle diameter: 20 nm) was mixed with a sample mill at 10,000 rpm for 30 seconds. Thereafter, the mixture was sieved using a vibrating sieve with an opening of 45 μm to prepare a toner (7). The volume average particle diameter of the obtained toner (7) was 5.9 μm.
Table 1 shows the Ti content and ratio (Ti content/Si content) in the obtained toner (7).

<Comparative example 1>
To 100 parts by mass of toner particles (1), 2.0 parts by mass of specific silica particles (1) (first silica particles, BET specific surface area: 130 m ² /g, number average particle diameter: 60 nm) and hydrophobic 1.0 parts by mass of silica (second silica particles, manufactured by Nippon Aerosil Co., Ltd., RY50, BET specific surface area: 25 m ² /g, number average particle diameter: 140 nm) were mixed and blended for 30 seconds at 10,000 rpm using a sample mill. . Thereafter, the mixture was sieved using a vibrating sieve with an opening of 45 μm to prepare a toner (C1). The volume average particle diameter of the obtained toner (C1) was 5.9 μm.
Table 1 shows the Ti content and ratio (Ti content/Si content) in the obtained toner (C1).

<Comparative example 2>
Toner (C2) was prepared in the same manner as toner (1) except that the amount of hydrophobic titanium oxide mixed in advance with respect to hydrophobic silica was 0.30% by mass. did. The volume average particle diameter of the obtained toner (C2) was 5.9 μm.
Table 1 shows the Ti content and ratio (Ti content/Si content) in the obtained toner (C2).

<Preparation of carrier>
Spherical magnetite powder particles (volume average particle diameter: 0.55 μm): After thoroughly stirring 500 parts with a Henschel mixer, 5.0 parts of a titanate coupling agent was added, the temperature was raised to 100°C, and the mixture was mixed and stirred for 30 minutes. Spherical magnetite particles coated with a titanate coupling agent were obtained.
Subsequently, in a four-necked flask, 6.25 parts of phenol, 9.25 parts of 35% by mass formalin, 500 parts of the titanate-based coupling agent-coated spherical magnetite particles, and 6.25 parts of 25% by mass aqueous ammonia were added. and 425 parts of water were mixed and stirred. Next, the mixture was reacted at 85° C. for 120 minutes with stirring, then cooled to 25° C., 500 parts of water was added, the supernatant liquid was removed, and the precipitate was washed with water. This was dried under reduced pressure at 150° C. or higher and 180° C. or lower to obtain a carrier having a volume average particle diameter of 35 μm.

<Preparation of developer>
The obtained toners and carriers were placed in a V-blender at a ratio of toner:carrier = 5:95 (mass ratio) and stirred for 20 minutes to obtain each developer.

<Evaluation>
(Image evaluation under high temperature and high humidity environment)
The developer of each example was stored in the developing device of a modified image forming apparatus Apeos Port IV C5575 (manufactured by Fuji Xerox). Using this modified machine, after leaving it for one day in a high temperature and high humidity environment (30°C, 85% RH), images with an image density of 1% were continuously formed on 15,000 sheets of A4 paper, and color streaks were formed according to the following criteria. The occurrence of was evaluated. Note that grades up to G3 were considered to be within the allowable range.

G1: No color streaks occur G2: Color streaks occur between the 12,500th and 15,000th images G3: Color streaks occur between the 10,000th and 12,499th images G4: Color streaks occur between the 5,000th and 9,999th images G5: Color streaks occur between the 4,999th images

(Image evaluation under low temperature and low humidity environment)
The developer of each example was stored in the developing device of a modified image forming apparatus Apeos Port IV C5575 (manufactured by Fuji Xerox). Using this modified machine, after leaving it for one day in a low temperature, low humidity environment (10°C, 15% RH), images with an image density of 5% were continuously formed on 15,000 sheets of A4 paper, and color streaks were determined according to the following criteria. The occurrence was evaluated. Note that grades up to G3 were considered to be within the allowable range.

G1: No color streaks occur G2: Color streaks occur between the 12,500th and 15,000th images G3: Color streaks occur between the 10,000th and 12,499th images G4: Color streaks occur between the 5,000th and 9,999th images G5: Color streaks occur between the 4,999th images

From the results in Table 1, it can be seen that in this example, the occurrence of color streaks due to poor cleaning was suppressed in both a high temperature, high humidity environment and a low temperature, low humidity environment, compared to the comparative example.

1Y, 1M, 1C, 1K photoreceptor (an example of image carrier)
2Y, 2M, 2C, 2K Charging roll (an example of charging means)
3 Exposure device (an example of electrostatic image forming means)
3Y, 3M, 3C, 3K Laser beam 4Y, 4M, 4C, 4K Developing device (an example of developing means)
5Y, 5M, 5C, 5K Primary transfer roll (an example of primary transfer means)
6Y, 6M, 6C, 6K Photoconductor cleaning device (an example of cleaning means)
8Y, 8M, 8C, 8K Toner cartridge 10Y, 10M, 10C, 10K Image forming unit 20 Intermediate transfer belt (an example of intermediate transfer body)
22 Drive roll 24 Support roll 26 Secondary transfer roll (an example of secondary transfer means)
30 Intermediate transfer member cleaning device 107 Photoreceptor (an example of an image carrier)
108 Charging roll (an example of charging means)
109 Exposure device (an example of electrostatic image forming means)
111 Developing device (an example of developing means)
112 Transfer device (an example of transfer means)
113 Photoconductor cleaning device (an example of cleaning means)
115 Fixing device (an example of fixing means)
116 Mounting rail 117 Housing 118 Opening for exposure 200 Process cartridge 300 Recording paper (an example of recording medium)
P Recording paper (an example of recording medium)

Claims (17)

toner particles;
an external additive containing silica particles;
has
At least one of the toner particles and the external additive contains Ti-containing particles,
The Ti content is 0.05 ppm or more and 18 ppm or less,
For electrostatic image development, the silica particles include silica particles A having a BET specific surface area of 100 m ² /g or more, and silica particles B having a BET specific surface area of 20 m ² /g or more and 90 m ² /g or less. toner. When the external addition amount of the silica particles A to the mass of the toner particles is WA mass %, and the external addition amount of the silica particles B to the toner particle mass is WB mass %, 0.01≦WA/WB≦ The toner for developing an electrostatic image according to claim 1, which satisfies the following. toner particles;
an external additive containing silica particles;
has
At least one of the toner particles and the external additive contains Ti-containing particles,
The Ti content is 0.05 ppm or more and 18 ppm or less,
A toner for developing an electrostatic image, wherein the silica particles include silica particles C having a number average particle size of 20 nm or more and 80 nm or less, and silica particles D having a number average particle size of more than 80 nm and 200 nm or less. When the amount of external addition of the silica particles C to the mass of the toner particles is WC mass %, and the amount of external addition of the silica particles D to the mass of the toner particles is WD mass %, 0.01≦WC/WD≦ 4. The toner for developing an electrostatic image according to claim 3, which satisfies the following. The toner for developing an electrostatic image according to any one of claims 1 to 4, wherein the Ti content is 0.1 ppm or more and 15 ppm or less. The toner for developing an electrostatic image according to any one of claims 1 to 5, wherein the Ti-containing particles are titanium oxide particles. The static powder according to any one of claims 1 to 6, wherein the toner particles have a volume average particle diameter of 4 μm or more and 9 μm or less, and the toner particles have an average circularity of 0.930 or more and 0.990 or less. Toner for developing charged images. The ratio of the Ti content to the Si content (Ti content/Si content) is 2×10 ^-6 or more and 2×10 ^-2 or less, according to any one of claims 1 to 7. Toner for developing electrostatic images. The toner for developing an electrostatic image according to any one of claims 1 to 8, wherein the toner particles contain a polyester resin. The toner for developing an electrostatic image according to claim 9, wherein the toner particles contain an amorphous polyester resin. The toner for developing an electrostatic image according to claim 10, wherein the toner particles contain a crystalline polyester resin. An electrostatic image developer comprising the toner for developing an electrostatic image according to any one of claims 1 to 11. The toner for developing an electrostatic image according to any one of claims 1 to 11,
A coated carrier in which the surface of a core material made of magnetic powder is coated with a coating resin, a magnetic powder-dispersed carrier in which magnetic powder is dispersed and blended in a matrix resin, and a resin-impregnated carrier in which porous magnetic powder is impregnated with resin. at least one carrier selected from the group consisting of carriers;
An electrostatic image developer containing. Containing the electrostatic image developing toner according to any one of claims 1 to 11,
A toner cartridge that can be attached to and removed from an image forming apparatus. Developing means containing the electrostatic image developer according to claim 12 or 13, and developing an electrostatic image formed on the surface of the image carrier as a toner image by the electrostatic image developer,
A process cartridge that can be attached to and removed from an image forming apparatus. an image holder;
Charging means for charging the surface of the image carrier;
an electrostatic charge image forming means for forming an electrostatic charge image on the surface of the charged image carrier;
A developing unit containing the electrostatic image developer according to claim 12 or 13, and developing an electrostatic image formed on the surface of the image carrier as a toner image by the electrostatic image developer;
a transfer means for transferring the toner image formed on the surface of the image carrier to the surface of a recording medium;
a cleaning means having a cleaning blade for cleaning the surface of the image carrier;
a fixing means for fixing the toner image transferred to the surface of the recording medium;
An image forming apparatus comprising: a charging step of charging the surface of the image carrier;
an electrostatic charge image forming step of forming an electrostatic charge image on the surface of the charged image carrier;
A developing step of developing the electrostatic image formed on the surface of the image carrier as a toner image using the electrostatic image developer according to claim 12 or 13;
a transfer step of transferring the toner image formed on the surface of the image carrier to the surface of a recording medium;
a cleaning step of cleaning the surface of the image carrier with a cleaning blade;
a fixing step of fixing the toner image transferred to the surface of the recording medium;
An image forming method comprising: