JP2016065963A - Toner mixture, electrostatic charge image developer, toner cartridge, developer cartridge, process cartridge, image forming apparatus, image forming method, and silica aggregate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner mixture that has suppressed the occurrence of fogging and photoreceptor filming even in a high-temperature and high-humidity environment.SOLUTION: There is provided a toner mixture that contains a toner for electrostatic charge image development and silica aggregate having particle diameters of 12 μm or more and 100 μm or less, and contains the silica aggregate in an amount of 0.01 weight% or more and 0.50 weight% or less relative to the toner for electrostatic charge image development, where when the hydrophobicity of the silica aggregate is A and the hydrophobicity of the silica aggregate after crushing is B, the following formulas (1) and (2) are satisfied. (1) 50≤A≤80 and (2) A-B≤5.SELECTED DRAWING: None

Description

  The present invention relates to a toner mixture, an electrostatic charge image developer, a toner cartridge, a developer cartridge, a process cartridge, an image forming apparatus, an image forming method, and a silica aggregate.

  A method of visualizing image information through an electrostatic charge image such as electrophotography is currently used in various fields. In electrophotography, an electrostatic charge image (electrostatic latent image) is formed on a photoreceptor (image carrier) by charging and exposure processes, the electrostatic latent image is developed with a developer containing toner, and a transfer and fixing process. It is visualized through. The developer used here includes a two-component developer comprising a toner and a carrier, and a one-component developer using a magnetic toner or a non-magnetic toner alone. The toner is usually produced by using a thermoplastic resin as a pigment. In addition, a kneading and pulverizing method is used in which the mixture is melt-kneaded with a release agent such as a charge control agent and wax, cooled, finely pulverized and further classified. In these toners, if necessary, inorganic and organic particles for improving fluidity and cleaning properties may be added to the toner particle surfaces.

Further, as a conventional toner, a toner described in Patent Document 1 is known.
Patent Document 1 discloses a toner having at least an external additive, wherein the external additive includes large-sized particles and small-sized particles having a volume average particle size smaller than the large-sized particles. the 2 g, 635 mesh, on a sieve of a mesh area 452Cm ^2, after air blow at a blow pressure 0.2MPa than a height 160mm on the sieve while the air suction at suction pressure 5 mmHg, the air suction at suction pressure 20mmHg In this case, a toner is disclosed in which the number of aggregates of the external additive remaining on the sieve is 4,500 or less and 5 or more.

JP 2007-93631 A

  An object of the present invention is to provide a toner mixture in which the occurrence of fogging and photoconductor filming is suppressed even under high temperature and high humidity.

The above-described problems of the present invention have been solved by the means described in <1> below. It is described below together with <2> to <10> which are preferred embodiments.
<1> A toner for developing an electrostatic image and a silica aggregate having a particle size of 12 μm or more and 100 μm or less, and the silica aggregate is 0.01% by weight or more and 0.50% based on the electrostatic charge developing toner. It is contained by weight% or less, and when the hydrophobization degree of the silica aggregate is A and the hydrophobization degree after pulverization of the silica aggregate is B, the following formulas (1) and (2) are satisfied. Toner mixture,
50 ≦ A ≦ 80 (1)
AB ≦ 5 (2)
<2> The toner mixture according to <1>, wherein the silica aggregate has a primary average particle diameter of 50 nm to 500 nm.
<3> An electrostatic charge image developer comprising the toner mixture according to <1> or <2> and a carrier,
<4> A toner cartridge that is detachable from the image forming apparatus and contains the toner mixture according to <1> or <2>,
<5> A developer cartridge containing the electrostatic image developer according to <3>,
<6> A process cartridge comprising a developer holder that contains the electrostatic image developer according to <3> and holds and conveys the electrostatic image developer.
<7> Image carrier, charging unit for charging the image carrier, exposure unit for exposing the charged image carrier to form an electrostatic latent image on the surface of the image carrier, and development including toner Developing means for developing the electrostatic latent image with an agent to form a toner image, transfer means for transferring the toner image from the image carrier to the surface of the transfer target, and toner transferred to the surface of the transfer target An image forming apparatus, wherein the developer is the toner mixture according to <1> or <2>, or the electrostatic charge image developer according to <3>.
<8> A latent image forming step for forming an electrostatic latent image on the surface of the image carrier, and development for forming the toner image by developing the electrostatic latent image formed on the surface of the image carrier with a developer containing toner. <1> or <2> as the developer, including a step, a transfer step of transferring the toner image onto the surface of the transfer target, and a fixing step of fixing the toner image transferred onto the surface of the transfer target. An image forming method using the toner mixture according to 1 or the electrostatic charge image developer according to <3>,
<9> When the particle diameter is 12 μm or more and 100 μm or less, the degree of hydrophobicity before crushing is A, and the degree of hydrophobicity after crushing is B, the following formulas (1) and (2) are satisfied. Silica aggregates characterized,
50 ≦ A ≦ 80 (1)
AB ≦ 5 (2)
<10> The silica aggregate according to <9>, wherein the primary average particle diameter is from 50 nm to 500 nm.

According to the invention described in <1> above, by using a specific amount of a specific silica aggregate in which a decrease in the degree of hydrophobicity is suppressed even after pulverization, compared to the case of using a conventional silica aggregate. Further, it is possible to provide a toner mixture in which the occurrence of fogging and photoconductor filming is suppressed even under high temperature and high humidity.
According to the invention described in the above <2>, fogging and photoconductor filming are generated even under high temperature and high humidity as compared with the case where the primary average particle diameter of the silica aggregate is less than 50 nm or more than 500 nm. Can be provided.
According to the invention described in <3> above, by using a specific amount of a specific silica aggregate in which a decrease in the degree of hydrophobicity is suppressed even after crushing, compared to the case of using a conventional silica aggregate. Further, it is possible to provide an electrostatic charge image developer in which the occurrence of fog and photoreceptor filming is suppressed even under high temperature and high humidity.
According to the invention described in <5> above, by using a specific amount of a specific silica aggregate in which a decrease in the degree of hydrophobicity is suppressed even after pulverization, compared to the case where a conventional silica aggregate is used. It is possible to provide a toner cartridge containing a toner mixture in which the occurrence of fogging and photoconductor filming is suppressed even under high temperature and high humidity.
According to the invention described in <6> above, by using a specific amount of a specific silica aggregate in which a decrease in the degree of hydrophobicity is suppressed even after crushing, compared to the case of using a conventional silica aggregate. It is possible to provide a process cartridge containing an electrostatic charge image developer in which the occurrence of fog and photoconductor filming is suppressed even under high temperature and high humidity.
According to the invention described in <7> above, by using a specific amount of a specific silica aggregate in which a decrease in the degree of hydrophobicity is suppressed even after crushing, compared to the case of using a conventional silica aggregate. It is possible to provide an image forming apparatus in which the occurrence of fogging and photoconductor filming is suppressed even under high temperature and high humidity.
According to the invention described in <8> above, by using a specific amount of a specific silica aggregate in which a decrease in the degree of hydrophobicity is suppressed even after crushing, compared to the case of using a conventional silica aggregate. Further, it is possible to provide an image forming method in which generation of fog and photoconductor filming is suppressed even under high temperature and high humidity.
According to the invention described in <9>, it is possible to provide a silica aggregate that is preferably used for a toner mixture in which generation of fogging and photoconductor filming is suppressed even under high temperature and high humidity. it can.
According to the invention described in <10>, the silica aggregate is preferably used for a toner mixture in which the occurrence of fogging and photoconductor filming is further suppressed even under high temperature and high humidity. Can do.

Hereinafter, the present embodiment will be described.
In the present embodiment, the description “A to B” represents not only a range between A and B but also a range including A and B at both ends thereof. For example, if “A to B” is a numerical value range, “A or more and B or less” or “B or more and A or less” is represented.

(Toner mixture)
The toner mixture of the present embodiment contains an electrostatic charge image developing toner and a silica aggregate of 12 μm or more and 100 μm or less, and the silica aggregate is 0.01% by weight or more and 0% by weight based on the electrostatic charge developing toner. When the hydrophobization degree of the silica aggregate is A and the hydrophobization degree after crushing of the silica aggregate is B, the following formulas (1) and (2) are satisfied. It is characterized by.
50 ≦ A ≦ 80 (1)
AB ≦ 5 (2)

In Patent Document 1, a small amount of agglomerates of an external additive is mixed in a toner, so that the agglomerates are gradually crushed according to the stirring time of the developer and adhere to the toner surface, so that long-term transfer can be performed. It is described that the image can be maintained uniformly, and a uniform image can be obtained regardless of the image area of the output image.
The present inventors have found that when the aggregate of the external additive described in Patent Document 1 is used, fogging occurs under high temperature and high humidity. As a result of intensive studies on the cause of the present inventors, the silica aggregate described in Patent Document 1 is formed by agglomerating the low hydrophobized sites, and the low hydrophobized sites are formed by crushing the aggregate. As a result, it was estimated that fog caused by charge leakage occurred in a high temperature and high humidity environment.
Therefore, by employing a specific silica aggregate that does not decrease the degree of hydrophobicity even after crushing, it is found that the occurrence of fog is suppressed even under high temperature and high humidity, and the present invention is completed. It reached.

<Silica aggregate>
The toner mixture of this embodiment contains a silica aggregate.
In this embodiment, the silica aggregate having a particle size of 12 to 100 μm is contained in an amount of 0.01 to 0.50% by weight based on the electrostatic charge image developing toner. When the content of the silica aggregate having a particle diameter of 12 to 100 μm is less than 0.01% by weight, the transfer maintenance property is not sufficient. On the other hand, if it exceeds 0.50% by weight, photoconductor filming due to aggregates may occur.
The content of the silica aggregate having a particle size of 12 to 100 μm is preferably 0.01 to 0.3% by weight, preferably 0.01 to 0.2% by weight, based on the electrostatic image developing toner. More preferably, it is 0.01 to 0.1% by weight.
It is considered that the silica aggregate of this embodiment is gradually crushed in the developing machine, and the crushed silica particles are supplied to the toner as an external additive, so that the transfer maintainability is kept good.
In this embodiment, the silica aggregate is gradually crushed to a smaller particle diameter by stirring in the developing device. Accordingly, in a state before use, it is preferable to contain 0.01 to 0.5% by weight of a silica aggregate having a particle size of 12 to 100 μm. Even if it is out of the above range after long-term use, If it is within the above-mentioned range in this state, it belongs to this embodiment.

In this embodiment, the silica aggregate is considered not to be developed together with the toner. It is not excluded that a part of the image is developed.
The silica aggregate pulverized product, which has been crushed to a smaller particle size, adheres to the toner as an external additive and is developed.
In this embodiment, even when the silica aggregate is filmed on the photoconductor without being crushed, the polar substances in the atmosphere are difficult to adsorb due to the small number of low hydrophobic sites, resulting in electrical leakage. Hateful.

In the present embodiment, the content of the silica aggregate having a particle size of 12 to 100 μm is measured by the following method.
The toner was air blown at a blow pressure of 0.2 MPa from a height of 160 mm on the screen while sucking air at a suction pressure of 5 mmHg on a sieve having a mesh size of 12 μm (made by Asada Mesh Co., Ltd., special order). Thereafter, when air is sucked at a suction pressure of 20 mmHg, the weight of the aggregate of the external additive remaining on the sieve is confirmed, and the weight is calculated from the ratio to the amount of input toner.

The content of particles having a particle diameter exceeding 100 μm as the silica aggregate is preferably 5% by number or less, more preferably 1% by number or less, and more preferably 0.1% by number of the entire silica aggregate. More preferably, it is as follows. When the content of the silica aggregate having a particle diameter exceeding 100 μm is within the above range, the amount of the silica particles crushed by stirring in the developing device is appropriately maintained, and the transfer maintaining property is excellent.
Further, the content of the silica aggregate having a particle size of less than 12 μm is preferably 10% by weight or less, more preferably 5% by weight or less, and more preferably 3% by weight or less of the entire silica aggregate. Further preferred. When the content of the silica aggregate having a particle diameter of less than 12 μm is within the above range, the silica particles are gradually supplied by crushing, and the transfer maintenance property is excellent. The content of the silica aggregate having a particle size of less than 12 μm is considered to gradually increase by stirring in the developing device. Therefore, the content of the silica aggregate having a particle size of less than 12 μm is preferably the above content before use.

In this embodiment, the primary average particle size of the silica aggregate is preferably 50 to 500 nm. More preferably, it is 50-300 nm, and still more preferably 50-150 nm. When the primary average particle diameter of the silica aggregate is within the above range, the transferability of the toner is improved when it is externally added to the toner.
In addition, the average primary particle diameter of a silica aggregate is measured as follows.
Prepare a toner with an opening of 100 μm mesh (manufactured by Asada Mesh Co., Ltd., custom-made) and an opening of 12 μm mesh (manufactured by Asada Mesh Co., Ltd., custom-made). After air blowing at a blow pressure of 0.2 MPa from a height of 160 mm above the screen while air is sucked in, the aggregate of the external additive remaining on the screen is sucked when air is sucked at a suction pressure of 20 mmHg. Then, using a scanning electron microscope (for example, manufactured by Hitachi, Ltd .: S-4100, etc.), the external additive was observed to take an image, and this image was analyzed by an image analyzer (for example, LUZEX III, manufactured by Nireco Corporation). The equivalent circle diameter of 300 primary particles taken in is measured to determine the average value, and the number average particle diameter is measured. In the electron microscope, the magnification is adjusted so that about 10 or more and 50 or less external additives can be seen in one visual field, and the number average particle diameter is obtained by observing a plurality of visual fields.

[Hydrophobicity]
In the present embodiment, when the hydrophobicity of the silica aggregate is A, the following formula (1) is satisfied.
50 ≦ A ≦ 80 (1)
When the hydrophobization degree of the silica aggregate is less than 50, the hydrophobization degree is not sufficient and fogging due to charge leakage occurs. On the other hand, when the degree of hydrophobicity exceeds 80, the cohesive strength of the silica aggregate becomes weak, and it is rapidly crushed in the developing device, so that the transfer maintenance property is not sufficient.
The degree of hydrophobicity of the silica aggregate is preferably 55 to 80, more preferably 55 to 70, and still more preferably 60 to 70.

In this embodiment, when the hydrophobization degree of the silica aggregate is A and the hydrophobization degree after crushing the silica aggregate is B, the following formula (2) is satisfied.
AB ≦ 5 (2)
Formula (2) shows that even if the silica aggregate is crushed, its degree of hydrophobicity is little changed. When AB exceeds 5, the low hydrophobization site is exposed due to the crushing of the aggregates, and thus fogging occurs due to charge leakage in a high temperature and high humidity environment.
In the present embodiment, AB is preferably 4 or less, more preferably 3 or less, and even more preferably 2 or less. When AB is within the above range, generation of fog is suppressed along with charge leakage even in a high temperature and high humidity environment. The lower limit of AB is not particularly limited, but is usually 0 or more.
As described above, in the present embodiment, the silica aggregate has little decrease in the degree of hydrophobicity even after pulverization. On the other hand, the conventional silica aggregates are reduced in hydrophobicity by crushing. The conventional silica aggregate is considered to aggregate due to hydrogen bonds between Si-OH groups, but the silica aggregate used in this embodiment has weak aggregation derived from intermolecular force between hydrophobic groups. As it is assumed that they are formed, they are easily crushed in the developing machine, and the hydrophobicity of the crushed silica particles is high. It is thought that the occurrence of is suppressed.

Regarding the degree of hydrophobicity B, the silica aggregate is crushed under the following conditions.
Specifically, 30 g of silica agglomerate is put in a 0.4 L sample mill (manufactured by Kyoritsu Riko Co., Ltd., sample mill SK-M10R type), and the agglomerates are mixed by mixing at 10,000 rpm for 60 seconds. Crush.

In the present embodiment, the degree of hydrophobicity is measured by the following method.
That is, 50 ml of ion-exchanged water, 0.2 g of silica agglomerate as a sample and its crushed material were put in a beaker, methanol was dropped from a burette while stirring with a magnetic stirrer, and the methanol water mixed solution at the end point where the total amount of the sample sank The methanol weight fraction is defined as the degree of hydrophobicity.

[Method for producing silica aggregate]
In the present embodiment, the method for producing the silica aggregate is not particularly limited, as long as the silica aggregate satisfying the above characteristics is obtained, silica particles are obtained using water glass as a raw material, and this is used as an aggregate. Examples thereof include a method in which a silica compound represented by alkoxysilane is used as a raw material, and particles are produced by a sol-gel method, silica particles are obtained by a so-called wet method, and this is used as an aggregate.
Among these, in the present embodiment, the silica particles constituting the silica aggregate are preferably produced by a wet method.

-Preparation method of silica particles-
The method for producing silica particles includes (1) a step of preparing an alkali catalyst solution containing an alkali catalyst at a concentration of 0.6 mol / L or more and 0.87 mol / L or less in a solvent containing alcohol (hereinafter referred to as “alkali catalyst”). And (2) the tetraalkoxysilane is supplied to the alcohol in the alkali catalyst solution, and the total supply amount of the tetraalkoxysilane is supplied per minute. It is preferable to have a step of supplying an alkali catalyst at 0.1 mol or more and 0.4 mol or less (hereinafter also referred to as a “particle generation step”) with respect to 1 mol. Moreover, it is preferable to have the process (henceforth "hydrophobization process process") which hydrophobizes the silica particle obtained in the said particle | grain production | generation process.
That is, in the method for producing silica particles, in the presence of the alcohol containing the alkali catalyst at the above concentration, while supplying the raw material tetraalkoxysilane and the alkali catalyst as a catalyst separately in the above relationship, In this method, silica particles are produced by reacting tetraalkoxysilane.

Here, the supply amount of tetraalkoxysilane is preferably 0.002 mol / (mol · min) or more and less than 0.006 mol / (mol · min), and is dropped by setting the supply amount within the above range. It is considered that the tetraalkoxysilane is supplied to the core particles evenly before the reaction probability between the tetraalkoxysilanes is lowered by reducing the contact probability between the tetraalkoxysilane and the core particles. Therefore, it is considered that the reaction between the tetraalkoxysilane and the core particles can be generated without unevenness. As a result, it is considered that the dispersion of particle growth is suppressed and silica particles with a narrow distribution width can be produced.
Therefore, it is considered that when the supply amount of tetraalkoxysilane is in the above range, silica particles (primary particles) in which the average circularity and the above-described various characteristics are in the above range are easily generated.
The volume average particle diameter of the silica particles is considered to depend on the total supply amount of tetraalkoxysilane.

(1) Alkali catalyst solution preparation step First, the alkali catalyst solution preparation step will be described.
In the alkali catalyst solution preparation step, a solvent containing alcohol is prepared, and an alkali catalyst is added thereto to prepare an alkali catalyst solution.
The solvent containing alcohol may be a solvent of alcohol alone, ketones such as water, acetone, methyl ethyl ketone, methyl isobutyl ketone, cellosolves such as methyl cellosolve, ethyl cellosolve, butyl cellosolve, cellosolve acetate, dioxane, tetrahydrofuran, etc. It may be a mixed solvent with other solvents such as ethers. In the case of a mixed solvent, the amount of alcohol relative to the other solvent is preferably 80% by weight or more (preferably 90% by weight or more).
Examples of the alcohol include lower alcohols such as methanol and ethanol.

On the other hand, the alkali catalyst is a catalyst for accelerating the reaction (hydrolysis reaction, condensation reaction) of tetraalkoxysilane, and examples thereof include basic catalysts such as ammonia, urea, monoamine, quaternary ammonium salts, Ammonia is particularly desirable.
The concentration (content) of the alkali catalyst is preferably 0.6 mol / L to 0.87 mol / L, more preferably 0.63 mol / L to 0.78 mol / L, and still more preferably 0.66 mol. / L to 0.75 mol / L.
When the concentration of the alkali catalyst is 0.6 mol / L or more, dispersibility in the growth process of the generated core particles is obtained, and gelation is achieved by reducing the generation of coarse aggregates such as secondary aggregates. The particle size distribution is controlled within a suitable range. On the other hand, when the concentration of the alkali catalyst is 0.87 mol / L or less, the stability of the produced core particles is not excessively large, the formation of true spherical core particles is suppressed, and atypical silica particles are obtained. It is done.
In addition, the density | concentration of an alkali catalyst is a density | concentration with respect to an alcohol catalyst solution (an alkali catalyst + solvent containing alcohol).

(2) Particle Generation Step Next, the particle generation step will be described.
In the particle generation step, tetraalkoxysilane and an alkali catalyst are respectively supplied to an alkali catalyst solution, and the tetraalkoxysilane is reacted (hydrolysis reaction, condensation reaction) in the alkali catalyst solution to obtain silica particles. Is a step of generating.
In this particle generation process, after the core particles are generated by reaction of tetraalkoxysilane at the initial supply stage of the tetraalkoxysilane (core particle generation stage), the core particles are grown (core particle growth stage), and then the silica particles. Produces.

Examples of the tetraalkoxysilane supplied into the alkali catalyst solution include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, and the like. From the viewpoints of diameter, particle size distribution, etc., tetramethoxysilane and tetraethoxysilane are preferred.
The supply amount of tetraalkoxysilane is preferably 0.002 mol / (mol · min) to 0.011 mol / (mol · min) with respect to the alcohol in the alkali catalyst solution.
This means that tetraalkoxysilane is supplied at a supply rate of 0.002 mol to 0.011 mol per minute with respect to 1 mol of alcohol used in the step of preparing the alkali catalyst solution.
When the supply amount of tetraalkoxysilane is 0.002 mol / (mol · min) or more, the time is shortened until the total supply amount of tetraalkoxysilane is dropped, and the production efficiency is good. When the supply amount of tetraalkoxysilane is 0.011 mol / (mol · min) or less, the reaction between the tetraalkoxysilanes is suppressed, the reaction between the dropped tetraalkoxysilane and the core particles is promoted, and the core particles are supplied. This is preferable because uneven distribution of tetraalkoxysilane supply is suppressed, variation in the formation of core particles is suppressed, and the distribution width of the shape distribution is suppressed.
The supply amount of tetraalkoxysilane is preferably 0.002 mol / (mol · min) to 0.0055 mol / (mol · min), and 0.002 mol / (mol · min) to 0.0045 mol / (mol · min). min), more preferably 0.002 mol / (mol · min) to 0.0035 mol / (mol · min).
The particle size of the silica particles depends on the type of tetraalkoxysilane and the reaction conditions, but the total supply amount of tetraalkoxysilane used in the particle generation reaction is, for example, 0.855 mol with respect to 1 L of silica particle dispersion. By setting the amount to 3.288 mol or less, the volume average particle diameter can be efficiently adjusted to the above range.

On the other hand, examples of the alkali catalyst supplied into the alkali catalyst solution include those exemplified above. The alkali catalyst to be supplied may be the same type as the alkali catalyst previously contained in the alkali catalyst solution, or may be a different type, but is preferably the same type.
The supply amount of the alkali catalyst is preferably 0.1 mol or more and 0.4 mol or less, more preferably 0.14 mol or more and 0 mol per mol of the total supply amount of tetraalkoxysilane supplied per minute. .35 mol or less, more preferably 0.18 mol or more and 0.30 mol or less.
When the supply amount of the alkali catalyst is 0.1 mol or more, the dispersibility of the core particles in the growth process of the generated core particles is obtained, the generation of coarse aggregates such as secondary aggregates is reduced, and gelation occurs. The particle size distribution is controlled within a suitable range. On the other hand, when the supply amount of the alkali catalyst is 0.4 mol or less, the stability of the generated core particles does not become excessive.

Here, in the particle generation step, tetraalkoxysilane and an alkali catalyst are supplied to the alkali catalyst solution, respectively, but this supply method may be a continuous supply method or intermittently. A supply method may be used.
In the particle generation step, the temperature of the alkaline catalyst solution (temperature at the time of supply) is preferably 5 ° C. or higher and 50 ° C. or lower, more preferably 15 ° C. or higher and 40 ° C. or lower.
Silica particles are obtained through the above steps. In this state, the obtained silica particles are obtained in the state of a dispersion, but may be used as a silica particle dispersion as it is, or may be used after removing the solvent as a powder of silica particles.
When the temperature of the alkali catalyst solution is increased, the primary particle diameter of the silica particles tends to be reduced, and when the temperature of the alkali catalyst solution is decreased, the primary particle diameter of the silica particles tends to be increased.

(3) Hydrophobic treatment step Since the silica particles obtained as described above are hydrophilic silica particles, it is preferable to hydrophobize the surface of the silica particles with a hydrophobizing agent.
Examples of the hydrophobizing agent include known organosilicon compounds having an alkyl group (eg, methyl group, ethyl group, propyl group, butyl group). Specific examples include, for example, silazane compounds (eg, methyl trimethyl compound). Silane compounds such as methoxysilane, dimethyldimethoxysilane, trimethylchlorosilane, and trimethylmethoxysilane, hexamethyldisilazane, tetramethyldisilazane, and the like. The hydrophobizing agent may be used alone or in combination.
Among these hydrophobizing agents, organosilicon compounds having a trimethyl group such as trimethylmethoxysilane and hexamethyldisilazane are suitable.
The amount of the hydrophobizing agent used is not particularly limited, but in order to obtain a hydrophobizing effect, for example, it is preferably 1% by weight or more and 100% by weight or less, and preferably 5% by weight or more and 80% by weight or less. The following is more preferable.

  As a method of obtaining a hydrophobic silica particle dispersion subjected to a hydrophobic treatment with a hydrophobic treatment agent, a wet method in which a required amount of a hydrophobic treatment agent is added to the silica particle dispersion and reacted, and hydrophilic silica particles An example is a dry method in which after the powder is obtained, a hydrophobizing treatment is performed by adding a hydrophobizing agent. Among these, it is preferable to carry out by a dry method from the viewpoint of a high degree of hydrophobicity and suppressing a decrease in the degree of hydrophobicity due to crushing.

As a hydrophobization treatment by a wet method, for example, a required amount of a hydrophobization treatment agent is added to a silica particle dispersion, and the reaction is performed in a temperature range of 30 ° C. or more and 80 ° C. or less with stirring, thereby hydrophobizing silica particles. To obtain a hydrophobic silica particle dispersion. When the reaction temperature is 30 ° C. or higher, the hydrophobization reaction easily proceeds, and when it is 80 ° C. or lower, the self-condensation of the hydrophobizing agent is suppressed, and the gelation of the dispersion and the aggregation of the silica particles are suppressed. The
In the wet method, it is difficult to set the degree of hydrophobicity within the target range.

In this embodiment, it is preferable to perform the hydrophobization treatment by a dry method.
After the particle generation step, the silica particle dispersion is dried to obtain a powder of hydrophilic silica particles, and then a hydrophobic treatment is performed by adding a hydrophobizing agent to obtain a powder of hydrophobic silica particles. Is mentioned.
Here, as a method of hydrophobizing the silica particles of the powder, the hydrophilic silica particles of the powder are stirred in a processing tank such as a Henschel mixer or a fluidized bed, and the hydrophobizing agent is added thereto, A method of gasifying the hydrophobizing agent by heating the inside and reacting it with silanol groups on the surface of the silica particles of the powder is mentioned. Although processing temperature is not specifically limited, For example, 100 to 150 degreeC is preferable, 110 to 140 degreeC is more preferable, and 120 to 130 degreeC is still more preferable.
Further, the hydrophobization treatment time is preferably 15 hours to 50 hours, more preferably 15 hours to 40 hours, and further preferably 15 hours to 30 hours.
By setting the hydrophobizing treatment temperature and the hydrophobizing treatment time within the above ranges, the uniformity of the hydrophobizing treatment is improved, and the residual low hydrophobized sites are suppressed.
Increasing the hydrophobization temperature tends to improve the degree of hydrophobicity A. In addition, by increasing the hydrophobic treatment time, the difference between the degree of hydrophobicity A and the degree of hydrophobicity B tends to be reduced.
Hydrophobic silica particles are obtained through the hydrophobization process described above.

-Method for producing silica aggregate-
The silica aggregate can be obtained by redispersing the silica particles produced as described above in a solvent, removing a certain amount of the solvent, compression molding, drying, and crushing to a desired particle size.
The solvent to be redispersed is preferably an alcohol solvent, and examples thereof include methanol and ethanol. Among these, it is preferable to redisperse in methanol.
The condition of the compression molding may be appropriately selected, for example, preferably a pressure is ^{40kg / cm 2 ~80kg / cm 2} , more preferably ^{50kg / cm 2 ~70kg / cm 2} , 55kg further preferably / cm ² ~65kg / cm ^2.
The pressurization time is preferably 30 seconds to 120 seconds, more preferably 30 seconds to 90 seconds, and further preferably 40 seconds to 80 seconds.
The silica aggregate is obtained by drying and further crushing the pellets obtained by compression molding as described above. At this time, the crushing conditions may be appropriately selected so as to obtain a desired particle size.
In order to obtain an aggregate having a desired particle size, it is also preferable to perform classification such as sieving.

<Toner for electrostatic image development>
In this embodiment, the toner mixture contains an electrostatic image developing toner. The toner for developing an electrostatic image preferably contains toner base particles and an external additive. Each will be described below.

[Toner mother particles]
The toner for developing an electrostatic charge image of the present embodiment preferably contains toner mother particles. The toner base particles preferably contain a binder resin, more preferably contain a binder and a release agent, and more preferably contain a colorant. The toner base particles may further contain a known additive such as a charge control agent.

-Binder resin-
Examples of the binder resin include styrenes (eg, styrene, parachlorostyrene, α-methylstyrene, etc.), (meth) acrylic acid esters (eg, methyl acrylate, ethyl acrylate, n-propyl acrylate, 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 (eg, vinyl methyl ether, vinyl isobutyl ether, etc.), vinyl ketones (vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone, etc.), olefins (eg, ethylene, propylene, etc.) Emissions, a homopolymer of a monomer such as butadiene) and the like, or a vinyl-based resin composed of these monomers with two or more combinations copolymer.
Examples of the binder resin include an epoxy resin, a polyester resin, a polyurethane resin, a polyamide resin, a cellulose resin, a polyether resin, a non-vinyl resin such as a modified rosin, a mixture of these and the above vinyl resin, or these Examples also include a graft polymer obtained by polymerizing a vinyl monomer in the coexistence.
These binder resins may be used alone or in combination of two or more.

A polyester resin is suitable as the binder resin.
Examples of the polyester resin include known polyester resins.
As a polyester resin, the condensation polymer of polyhydric carboxylic acid and polyhydric alcohol is mentioned, for example. In addition, as an amorphous polyester resin, a commercial item may be used and what was synthesize | combined may be used.

Examples of the polyvalent carboxylic acid include aliphatic dicarboxylic acids (for example, oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, alkenyl succinic acid, adipic acid, sebacic acid, etc. ), Alicyclic dicarboxylic acids (eg, cyclohexanedicarboxylic acid, etc.), aromatic dicarboxylic acids (eg, terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, etc.), their anhydrides, or lower ones thereof (eg, having 1 carbon atom) And 5 or less) alkyl esters. Among these, as polyvalent carboxylic acid, aromatic dicarboxylic acid is preferable, for example.
The polyvalent carboxylic acid may be used in combination with a dicarboxylic acid or a trivalent or higher carboxylic acid having a crosslinked structure or a branched structure. Examples of the trivalent or higher carboxylic acid include trimellitic acid, pyromellitic acid, anhydrides thereof, or lower (eg, having 1 to 5 carbon atoms) alkyl ester.
Polyvalent carboxylic acid may be used individually by 1 type, and may use 2 or more types together.

Examples of the polyhydric alcohol include aliphatic diols (for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, etc.), alicyclic diols (for example, cyclohexanediol, cyclohexanedimethanol, Hydrogenated bisphenol A, etc.) and aromatic diols (for example, ethylene oxide adducts of bisphenol A, propylene oxide adducts 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 trihydric or higher polyhydric alcohol having a crosslinked structure or a branched structure may be used together with the diol. Examples of the trihydric or higher polyhydric alcohol include glycerin, trimethylolpropane, and pentaerythritol.
A polyhydric alcohol may be used individually by 1 type, and may use 2 or more types together.

The glass transition temperature (Tg) of the polyester resin is preferably 50 ° C. or higher and 80 ° C. or lower, and more preferably 50 ° C. or higher and 65 ° C. or lower.
The glass transition temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC), and more specifically, described in the method for determining the glass transition temperature in JIS K-1987 “Method for Measuring Transition Temperature of Plastics”. It is determined by “extrapolated glass transition start temperature”.

The weight average molecular weight (Mw) of the 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 polyester resin is preferably 2,000 or more and 100,000 or less.
The molecular weight distribution Mw / Mn of the polyester resin is preferably 1.5 or more and 100 or less, and more preferably 2 or more and 60 or less.
The weight average molecular weight and the number average molecular weight are measured by gel permeation chromatography (GPC). The molecular weight measurement by GPC is carried out with a THF solvent using a GPC / HLC-8120 manufactured by Tosoh Corporation and a column / TSKgel SuperHM-M (15 cm) manufactured by Tosoh Corporation. The weight average molecular weight and the number average molecular weight are calculated using a molecular weight calibration curve prepared from a monodisperse polystyrene standard sample from this measurement result.

The polyester resin can be produced by a known production method. Specifically, for example, the polymerization temperature is set to 180 ° C. or higher and 230 ° C. or lower, the pressure in the reaction system is reduced as necessary, and the reaction is performed while removing water and alcohol generated during the condensation.
In addition, when the monomer of the raw material is not dissolved or compatible at the reaction temperature, a solvent having a high boiling point may be added and dissolved as a solubilizing agent. In this case, the polycondensation reaction is performed while distilling off the solubilizer. If a monomer with poor compatibility is present in the copolymerization reaction, the monomer with poor compatibility and the monomer and the acid or alcohol to be polycondensed are condensed in advance and then polymerized together with the main component. It is good to condense.

  The content of the binder resin is, for example, preferably 40 to 95% by weight, more preferably 50 to 90% by weight, and still more preferably 60 to 85% by weight with respect to the whole toner base particles.

-Colorant-
Examples of the colorant include carbon black, chrome yellow, hansa yellow, benzidine yellow, selenium yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, vulcan orange, watch young red, permanent red, brilliantamine 3B, brilliant. Carmine 6B, Dupont Oil Red, Pyrazolone Red, Resol 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, or acridine series, xanthene series, azo series Various dyes such as benzoquinone, azine, anthraquinone, thioindico, dioxazine, thiazine, azomethine, indico, phthalocyanine, aniline black, polymethine, triphenylmethane, diphenylmethane, and thiazole Can be mentioned.

A colorant may be used individually by 1 type and may use 2 or more types together.
As the colorant, a surface-treated colorant may be used as necessary, or it may be used in combination with a dispersant. A plurality of colorants may be used in combination.
The content of the colorant is, for example, preferably 1 to 30% by weight, and more preferably 3 to 15% by weight with respect to the whole toner base 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; ester types such as fatty acid esters and montanic acid esters Wax; and the like. The release agent is not limited to this.

The melting temperature of the release agent is preferably 50 ° C. or higher and 110 ° C. or lower, and more preferably 60 ° C. or higher and 100 ° C. or lower.
The melting temperature is determined from the DSC curve obtained by differential scanning calorimetry (DSC) according to the “melting peak temperature” described in JIS K-1987 “Method for measuring the transition temperature of plastics”.

  The content of the release agent is preferably 1 to 20% by weight, and more preferably 5 to 15% by weight with respect to the whole toner base particles.

-Other additives-
In addition to the above-described components, various components such as an internal additive and a charge control agent may be added to the toner base particles as necessary.
Examples of the internal additive include metals such as ferrite, magnetite, reduced iron, cobalt, nickel and manganese, alloys, and magnetic materials such as compounds containing these metals.
Examples of the charge control agent include quaternary ammonium salt compounds, nigrosine compounds, dyes composed of complexes of aluminum, iron, chromium, and triphenylmethane pigments.

The toner base particles used in the exemplary embodiment are not particularly limited by the production method, and a known method can be used. Specific examples include the following methods.
The production of the toner base particles is obtained, for example, by a kneading and pulverizing method in which a binder resin, a colorant, a release agent, and a charge control agent, if necessary, are kneaded, pulverized, and classified; To change the shape of the particles by mechanical impact force or thermal energy; dispersion of emulsified binder resin, dispersion of colorant, release agent, and charge control agent as required An emulsion aggregation method in which toner particles are obtained by mixing, aggregating and heating and fusing the solution; emulsion polymerization of a polymerizable monomer of a binder resin, and a formed dispersion, a colorant, a release agent, and , An emulsion polymerization aggregation method to obtain toner particles by mixing with a dispersion such as a charge control agent, if necessary, and then fusing and heat-fusing; a polymerizable monomer for obtaining a binder resin, a colorant, A suspension polymerization method in which a release agent and, if necessary, a solution such as a charge control agent are suspended in an aqueous solvent for polymerization; Resin and a colorant, releasing agent, and dissolution suspension method and granulated with a solution such as a charge control agent is suspended in an aqueous solvent optionally; or the like can be used. In addition, a manufacturing method may be performed in which the toner base particles obtained by the above method are used as a core, and aggregated particles are further adhered and heat-fused to have a core-shell structure.
Among these, the toner of the exemplary embodiment is preferably a toner (emulsion aggregation toner) obtained by an emulsion aggregation method or an emulsion polymerization aggregation method.

-Toner particle characteristics-
The toner particles may be toner particles having a single layer structure, or toner particles having a so-called core / shell structure composed of a core (core particle) and a coating layer (shell layer) covering the core. May be.
Here, the core / shell structure toner particles include, for example, a core portion including a binder resin and, if necessary, other additives such as a colorant and a release agent, and a binder resin. It is good to be comprised with the comprised coating layer.

The volume particle diameter (D50v) of the toner particles is preferably 2 μm or more and 10 μm or less, and more preferably 4 μm or more and 8 μm or less.
In addition, various particle diameters and various particle size distribution indexes of toner particles use Coulter Multisizer II (manufactured by Beckman Coulter, Inc.), and electrolytes use ISOTON-II (manufactured by Beckman Coulter, Inc.). Measured.
In the measurement, 0.5 mg to 50 mg of a measurement sample is added to 2 ml of a 5% aqueous solution of a surfactant (sodium alkylbenzenesulfonate is preferable) as a dispersant. This is added to 100 ml or more and 150 ml or less of the electrolytic solution.
The electrolyte in which the sample is suspended is dispersed for 1 minute with an ultrasonic disperser, and the particle size distribution of particles having a particle size in the range of 2 μm to 60 μm is measured using a 100 μm aperture with a Coulter Multisizer II. taking measurement. The number of particles to be sampled is 50,000.
A cumulative distribution is drawn from the smaller diameter side to the particle size range (channel) divided based on the measured particle size distribution, and the cumulative particle size of 16% is the volume particle size D16v. D16p, the particle size of 50% cumulative is defined as volume particle size D50v, several particle size D50p, and the particle size of cumulative 84% is defined as volume particle size D84v, several particle size D84p.
Using these, the volume average particle size distribution index (GSDv) is calculated as (D84v / D16v) ^1/2 and the number average particle size distribution index (GSDp) is calculated as (D84p / D16p) ^1/2 .

The shape factor SF1 of the toner particles is preferably 110 or more and 150 or less, and more preferably 120 or more and 140 or less.
The shape factor SF1 is obtained by the following formula.

In the above formula, ML represents the maximum length of each toner base particle, and A represents the projected area of each toner base particle.
The average value of the shape factor SF1 (average shape factor) is obtained by taking 1,000 toner images magnified 250 times from an optical microscope to an image analyzer (LUZEX III, manufactured by Nireco Corporation), and the maximum From the length and the projected area, the value of the SF1 is obtained and averaged for each particle.

(External additive)
In this embodiment, the electrostatic image developing toner preferably contains toner base particles and an external additive externally added to the toner base particles.
Examples of the external additive include inorganic particles. As the inorganic particles, TiO ₂ , 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 , Examples include K ₂ O. (TiO ₂ ) _n , Al ₂ O ₃ .2SiO ₂ , CaCO ₃ , MgCO ₃ , BaSO ₄ , MgSO _{4 and the} like.
The surface of the inorganic particles as an external additive is preferably subjected to a hydrophobic treatment. The hydrophobic treatment is performed, for example, by immersing inorganic particles in a hydrophobic 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 individually by 1 type and may use 2 or more types together.
The amount of the hydrophobizing agent is usually 1 part or more and 10 parts per 100 parts of inorganic particles, for example.
Part.

  Examples of external additives include resin particles (resin particles such as polystyrene, PMMA, and melamine resin), cleaning activators (for example, metal salts of higher fatty acids typified by zinc stearate, particles of a fluorine-based high molecular weight substance), and the like. Can be mentioned.

The volume average particle diameter of the external additive is preferably 3 to 500 nm, more preferably 5 to 100 nm, and still more preferably 5 to 50 nm.
The amount of the external additive described above is, for example, preferably 0.01% by weight to 5% by weight, and more preferably 0.01% by weight to 2.0% by weight with respect to the toner base particles. .

In the present embodiment, it is preferable to contain silica particles as an external additive. The volume average particle diameter of the silica particles is preferably 3 to 500 nm, more preferably 5 to 300 nm, and still more preferably 5 to 150 nm.
The content of the silica particles is preferably 0.01 to 10% by weight, more preferably 0.01 to 5% by weight, and more preferably 0.1 to 3% by weight with respect to the toner base particles. Is more preferable.

(Electrostatic image developer)
The toner mixture of this embodiment is preferably used as an electrostatic charge image developer.
The electrostatic image developer of this embodiment is not particularly limited except that it contains the toner mixture of this embodiment, and can take an appropriate component composition depending on the purpose. When the toner mixture of this embodiment is used alone, it is prepared as a one-component electrostatic image developer, and when used in combination with a carrier, it is prepared as a two-component electrostatic image developer.
As a one-component developer, a method in which a charged toner is formed by frictional charging with a developing sleeve or a charging member, and development is performed according to an electrostatic latent image is also applied.

  In the present embodiment, the development method is not particularly defined, but the two-component development method is preferable. The carrier is not particularly defined as long as the above conditions are satisfied. Examples of the carrier core material include magnetic metals such as iron, steel, nickel, and cobalt, alloys of these with manganese, chromium, rare earth, and the like, and Magnetic oxides such as ferrite and magnetite are mentioned, and from the viewpoint of core material surface properties and core material resistance, ferrite, particularly alloys with manganese, lithium, strontium, magnesium and the like are preferably mentioned.

The carrier used in this embodiment is preferably formed by coating the surface of the core material with a resin. There is no restriction | limiting in particular as said resin, According to the objective, it selects suitably. For example, polyolefin resins such as polyethylene and polypropylene; polyvinyl resins and polyvinylidene resins such as polystyrene, acrylic resins, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether and polyvinyl ketone Vinyl chloride-vinyl acetate copolymer; styrene-acrylic acid copolymer; straight silicone resin composed of organosiloxane bond or modified product thereof; polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polychlorotrifluoroethylene, etc. Fluorine resin; Silicone resin; Polyester; Polyurethane; Polycarbonate; Phenol resin; Urea-formaldehyde resin, Melamine tree , Benzoguanamine resins, urea resins, amino resins such as polyamide resins, epoxy resins, per se known resins and the like. These may be used individually by 1 type and may use 2 or more types together. In the present embodiment, among these resins, it is preferable to use at least a fluorine resin and / or a silicone resin. The use of at least a fluorine-based resin and / or a silicone resin as the resin is advantageous in that it has a high effect of preventing carrier contamination (impact) due to toner and external additives.
In the resin coating, resin particles and / or conductive particles are preferably dispersed in the resin. Examples of the resin particles include thermoplastic resin particles and thermosetting resin particles. Among these, thermosetting resins are preferable from the viewpoint of relatively easily increasing the hardness, and resin particles made of nitrogen-containing resin containing N atoms are preferable from the viewpoint of imparting negative chargeability to the toner. In addition, these resin particles may be used individually by 1 type, and may use 2 or more types together. The average particle diameter of the resin particles is preferably 0.1 to 2 μm, and more preferably 0.2 to 1 μm. When the average particle diameter of the resin particles is 0.1 μm or more, the resin particles are excellent in dispersibility in the coating film. On the other hand, when the average particle diameter is 2 μm or less, the resin particles are not easily dropped from the coating film.

  Examples of the conductive particles include metal particles such as gold, silver and copper, carbon black particles, and surfaces of titanium oxide, zinc oxide, barium sulfate, aluminum borate, potassium titanate powder, tin oxide, carbon black, metal And particles covered with the like. These may be used individually by 1 type and may use 2 or more types together. Among these, carbon black particles are preferable in terms of good production stability, cost, conductivity and the like. Although there is no restriction | limiting in particular as a kind of said carbon black, Since the DBP oil absorption amount is 50-250 ml / 100g, since it is excellent in manufacturing stability, it is preferable. The coating amount of the resin, the resin particles, and the conductive particles on the surface of the core material is preferably 0.5 to 5.0% by weight, and preferably 0.7 to 3.0% by weight. More preferred.

The method for forming the film is not particularly limited. For example, the resin particles such as crosslinkable resin particles and / or the conductive particles, and a styrene acrylic resin, a fluorine resin, a silicone resin as a matrix resin, etc. And a method of using a film-forming solution containing the above resin in a solvent.
Specifically, an immersion method in which the carrier core material is immersed in the film forming liquid, a spray method in which the film forming liquid is sprayed on the surface of the carrier core material, and the carrier core material is floated by flowing air. Examples thereof include a kneader coater method in which the film forming liquid is mixed in the state and the solvent is removed. Among these, the kneader coater method is preferable in the present embodiment.

  The solvent used for the film forming liquid is not particularly limited as long as it can dissolve only the resin as a matrix resin, and is selected from known solvents such as toluene, Aromatic hydrocarbons such as xylene, ketones such as acetone and methyl ethyl ketone, ethers such as tetrahydrofuran and dioxane, and the like. When the resin particles are dispersed in the coating, the resin particles and the matrix resin particles are uniformly dispersed in the thickness direction and the tangential direction of the carrier surface. Even when the coating is worn, it is possible to always maintain the same surface formation as when it is not used, and to maintain a good charge imparting ability for the toner over a long period of time. In the case where the conductive particles are dispersed in the coating, the conductive particles and the resin as the matrix resin are uniformly dispersed in the thickness direction and the tangential direction of the carrier surface. Even if the film is worn out over a long period of use of the carrier, the same surface formation as when not in use can always be maintained, and carrier deterioration is prevented for a long period of time. In addition, when the said resin particle and the said electroconductive particle are disperse | distributed to the said film, the above-mentioned effect is exhibited simultaneously.

The electric resistance of the magnetic carrier formed as described above in the state of a magnetic brush under an electric field of 10 ⁴ V / cm is preferably 10 ⁸ to 10 ¹³ Ωcm. When the electric resistance of the magnetic carrier is 10 ⁸ Ωcm or more, the adhesion of the carrier to the image portion on the image carrier is suppressed, and the brush mark is difficult to appear. On the other hand, when the electrical resistance of the magnetic carrier is 10 ¹³ Ωcm or less, the generation of the edge effect is suppressed and a good image quality is obtained.
The electrical resistance (volume specific resistance) is measured as follows.
A measuring jig that is a pair of 20 cm ² circular electrode plates (made of steel) connected to an electrometer (made by KEITHLEY, trade name: KEITHLEY 610C) and a high-voltage power supply (made by FLUKE, trade name: FLUKE 415B). The sample is placed on the lower electrode plate so as to form a flat layer having a thickness of about 1 mm to 3 mm. Next, after the upper electrode plate is placed on the sample, a weight of 4 kg is placed on the upper electrode plate in order to eliminate the gap between the samples. In this state, the thickness of the sample layer is measured. Next, the current value is measured by applying a voltage to the bipolar plate, and the volume resistivity is calculated based on the following equation.
Volume resistivity = applied voltage × 20 ÷ (current value−initial current value) ÷ sample thickness In the above formula, the initial current is the current value when the applied voltage is 0, and the current value indicates the measured current value.

  The mixing ratio of the toner and the carrier of this embodiment in the two-component electrostatic image developer is preferably 2 to 10 parts by weight of the electrostatic image developing toner with respect to 100 parts by weight of the carrier. Moreover, the preparation method of a developing agent is not specifically limited, For example, the method of mixing with a V blender etc. is mentioned.

(Image forming method)
The electrostatic charge image developer (toner mixture) is used in an electrostatic charge image development (electrophotographic) image forming method.
The image forming method of the present embodiment includes a latent image forming step of forming an electrostatic latent image on the surface of the image carrier, and developing the electrostatic latent image formed on the surface of the image carrier with a developer containing toner. A developing process for forming a toner image, a transfer process for transferring the toner image to the surface of the transfer body, a fixing process for fixing the toner image transferred to the surface of the transfer body, and the residual image on the image carrier. A cleaning step of cleaning the electrostatic charge image developer, wherein the toner mixture of the present embodiment or the electrostatic charge image developer of the present embodiment is used as the developer.

Each of the above steps is a general step per se, and is described in, for example, JP-A-56-40868 and JP-A-49-91231. Note that the image forming method of the present embodiment can be carried out by using a known image forming apparatus such as a copying machine or a facsimile machine.
The electrostatic latent image forming step is a step of forming an electrostatic latent image on an image carrier (photoconductor).
The developing step is a step of developing the electrostatic latent image with a developer layer on a developer holding member to form a toner image. The developer layer is not particularly limited as long as it contains the electrostatic image developing toner of this embodiment.
The transfer step is a step of transferring the toner image onto a transfer target. Examples of the transfer medium in the transfer process include an intermediate transfer medium and a recording medium such as paper.
In the fixing step, for example, there is a method of forming a copy image by fixing the toner image transferred onto the transfer paper by a heating roller fixing device in which the temperature of the heating roller is set to a constant temperature.
The cleaning step is a step of cleaning the developer remaining on the image carrier.
In the image forming method of the present embodiment, it is more preferable that the cleaning step includes a step of removing the electrostatic charge image developer remaining on the image carrier with a cleaning blade.
As the recording medium, known media can be used, for example, paper used for electrophotographic copying machines, printers, OHP sheets, etc. For example, the surface of plain paper is made of resin, etc. Coated coated paper, art paper for printing, and the like can be suitably used.

  The image forming method of the present embodiment may further include a recycling step. The recycling step is a step of transferring the electrostatic charge image developing toner collected in the cleaning step to the developer layer. The image forming method including the recycling process is performed using an image forming apparatus such as a toner recycling system type copying machine or facsimile machine. Further, the present invention may be applied to a recycling system that collects toner simultaneously with development.

(Image forming device)
The image forming apparatus according to this embodiment includes an image carrier, a charging unit that charges the image carrier, and an exposure unit that exposes the charged image carrier to form an electrostatic latent image on the surface of the image carrier. Developing means for developing the electrostatic latent image with a developer containing toner to form a toner image; transfer means for transferring the toner image from the image holding member to the surface of the transferred body; and the transferred body A fixing unit that fixes the toner image transferred to the surface; and a cleaning unit that cleans the image holding member. The toner mixture of the present embodiment or the electrostatic image developer of the present embodiment is used as the developer. It is characterized by using.
Note that the image forming apparatus according to the present exemplary embodiment includes at least the image holding member, the charging unit, the exposure unit, the developing unit, the transfer unit, the fixing unit, and the cleaning unit as described above. Although it does not specifically limit, The static elimination means etc. may be included as needed.
In the transfer unit, the transfer may be performed twice or more using an intermediate transfer member. Examples of the transfer medium in the transfer unit include an intermediate transfer medium and a recording medium such as paper.

As the image carrier and each means described above, the configurations described in the respective steps of the image forming method are preferably used. Any of the above-described means can be a known means in the image forming apparatus. Further, the image forming apparatus of the present embodiment may include means and devices other than those described above. Further, the image forming apparatus according to the present embodiment may simultaneously perform a plurality of the above-described means.
Examples of the cleaning means for cleaning the electrostatic charge image developer remaining on the image holding member include a cleaning blade and a cleaning brush, and a cleaning blade is preferable.
Preferred examples of the cleaning blade material include urethane rubber, neoprene rubber, and silicone rubber.

(Toner cartridge, developer cartridge, and process cartridge)
The toner cartridge of the present embodiment is a toner cartridge that contains at least the toner mixture of the present embodiment.
The developer cartridge of this embodiment is a developer cartridge that contains at least the electrostatic charge image developer of this embodiment.
In addition, the process cartridge according to the present embodiment includes a developing unit that develops an electrostatic latent image formed on the surface of the image carrier with the toner mixture or the electrostatic image developer to form a toner image, and an image carrier. And at least one selected from the group consisting of a charging means for charging the surface of the image carrier and a cleaning means for removing the toner remaining on the surface of the image carrier. This is a process cartridge containing at least the toner for developing an electrostatic image or the electrostatic image developer of this embodiment.

The toner cartridge of this embodiment is preferably detachable from the image forming apparatus. That is, in the image forming apparatus having a configuration in which the toner cartridge can be attached and detached, the toner cartridge of the present embodiment in which the toner of the present embodiment is stored is preferably used.
The developer cartridge of the present embodiment is not particularly limited as long as it contains the electrostatic charge image developer including the toner for developing an electrostatic charge image of the present embodiment. The developer cartridge is, for example, attached to or detached from an image forming apparatus including a developing unit, and includes the electrostatic image developer of the present embodiment as a developer to be supplied to the developing unit. Is stored.
The developer cartridge may be a cartridge that stores the toner mixture and the carrier, or may be a cartridge that stores the toner mixture and a cartridge that stores the carrier alone.
It is preferable that the process cartridge of the present embodiment is attached to and detached from the image forming apparatus.
In addition, the process cartridge according to the present embodiment may include other members such as a static elimination unit as necessary.
As the toner cartridge and the process cartridge, known configurations may be adopted. For example, Japanese Patent Application Laid-Open Nos. 2008-209489 and 2008-233736 are referred to.

  Hereinafter, although this embodiment is described in detail with examples, this embodiment is not limited in any way. In the following description, “parts” means “parts by weight” unless otherwise specified.

(Various measurement methods)
<Method for measuring weight average molecular weight and molecular weight distribution of resin>
The molecular weight and molecular weight distribution of the binder resin and the like were performed under the following conditions. GPC uses “HLC 8120GPC, SC 8020 (manufactured by Tosoh Corp.)”, two columns use “TSKgel, SuperHM H (6.0 mm ID × 15 cm, manufactured by Tosoh Corp.)”, and THF (eluent) Tetrahydrofuran) was used. As experimental conditions, an experiment was performed using a sample concentration of 0.5%, a flow rate of 0.6 mL / min, a sample injection amount of 10 μL, a measurement temperature of 40 ° C., and an IR detector. Moreover, the calibration curve is “polystylen standard sample TSK standard” manufactured by Tosoh Corporation: “A 500”, “F 1”, “F 10”, “F 80”, “F 380”, “A 2500”, “F 4 samples, “F 40”, “F 128”, and “F 700”.

<Volume average particle diameter of resin particles, colorant particles, toner, carrier, etc.>
The volume average particle diameter of resin particles, colorant particles, and the like was measured with a laser diffraction particle size distribution measuring device (LA 700, manufactured by Horiba, Ltd.).
As a measuring method, a sample in a dispersion is prepared so as to have a solid content of about 2 g, and ion exchange water is added thereto to make about 40 ml. This is put into the cell until an appropriate concentration is reached, waits for about 2 minutes, and is measured when the concentration in the cell is stable. The volume average particle diameter of each obtained channel was accumulated from the smaller volume average particle diameter, and the volume average particle diameter was determined to be 50%.

<Measuring method of melting point and glass transition temperature of resin>
The melting point of the crystalline polyester resin and the glass transition temperature (Tg) of the amorphous polyester resin were measured from the maximum peak measured by using a differential scanning calorimeter (Perkin Elmer: DSC 7) according to ASTM D34188. Asked. The temperature of the detection part of this apparatus (DSC 7) was corrected using the melting point of indium and zinc, and the heat of fusion was used for correcting the amount of heat. As the sample, an aluminum pan was used, an empty pan was set as a control, and the measurement was performed at a heating rate of 10 ° C./min.

<Method for Measuring Volume Average Particle Diameter of Toner Base Particle>
The volume average particle diameter of the toner base particles was measured using Coulter Multisizer II (manufactured by Beckman Coulter, Inc.). As the electrolytic solution, ISOTON-II (manufactured by Beckman Coulter, Inc.) was used.
As a measuring method, first, 0.5 mg to 50 mg of a measurement sample is added to 2 ml of a 5% aqueous solution of a surfactant, preferably sodium alkylbenzenesulfonate, as a dispersant, and this is added to 100 ml to 150 ml of the above electrolytic solution. Added. The electrolytic solution in which the measurement sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 minute, and the particle diameter is 2.0 μm to 60 μm using the Coulter Multisizer II with an aperture having an aperture diameter of 100 μm. The particle size distribution of particles in the range was measured. The number of particles to be measured was 50,000.
For the divided particle size range (channel), draw the cumulative distribution from the small diameter side with respect to the divided particle size range (channel), and define the 50% cumulative particle size as the heavy average particle size or volume average particle size, respectively. To do.

<Measuring method of particle diameter and content of silica aggregate>
Prepare a toner with an opening of 100 μm mesh (manufactured by Asada Mesh Co., Ltd., custom-made) and an opening of 12 μm mesh (manufactured by Asada Mesh Co., Ltd., custom-made). Of the external additive aggregate remaining on the sieve when air is blown at a blow pressure of 0.2 MPa from a height of 160 mm above the sieve while air is sucked at The weight was confirmed, and the weight was calculated from the ratio with the input toner amount.
If necessary, a 100 μm mesh was placed on the top.

<Method of measuring the degree of hydrophobicity>
50 ml of ion-exchanged water, 0.2 g of the resilica aggregate to be sampled and its crushed material are put into a beaker, methanol is dropped from the burette while stirring with a magnetic stirrer, and the methanol in the methanol water mixed solution at the end point where the total amount of the sample sinks. The weight fraction was defined as the degree of hydrophobicity.
Regarding the degree of hydrophobicity B, the silica aggregates were crushed under the following conditions.
20 g of silica aggregate was put into a 0.4 L sample mill (manufactured by Kyoritsu Riko Co., Ltd., sample mill SK-M10R type), and the aggregate was crushed by mixing at 10,000 rpm for 60 seconds.

<Measurement method of primary particle size>
Prepare an opening of 100 μm mesh (made by Asada Mesh Co., Ltd., special order product) on the upper stage, and a 12 μm mesh (made by Asada Mesh Co., Ltd., special order product) on the lower stage, and air on the sieve at a suction pressure of 5 mmHg. The agglomerates of the external additive remaining on the sieve when the air is blown at a blow pressure of 0.2 MPa from the height of 160 mm on the sieve while sucking and then air is sucked at a suction pressure of 20 mmHg, are scanned. Using an electron microscope (for example, S-4100, manufactured by Hitachi, Ltd.), the external additive was observed to take an image, and this image was taken into an image analyzer (for example, LUZEX III, manufactured by Nireco Corporation) 300 The equivalent circle diameter of each primary particle is measured, the average value is obtained, and the primary particle diameter is measured. In the electron microscope, the magnification was adjusted so that about 10 or more and 50 or less external additives could be seen in one visual field, and the number average primary particle diameter was obtained by observing multiple visual fields.

(Production of toner particles)
<Preparation of toner particles (1)>
[Preparation of resin particle dispersion (1)]
・ Styrene (manufactured by Wako Pure Chemical Industries, Ltd.): 320 parts ・ n-butyl acrylate (manufactured by Wako Pure Chemical Industries, Ltd.): 80 parts ・ β-carboxyethyl acrylate (manufactured by Rhodia Nikka Co., Ltd.): 9 Part · 1′10-decanediol diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.): 1.5 parts · dodecanethiol (manufactured by Wako Pure Chemical Industries, Ltd.): 2.7 parts Then, a solution of 4 parts of anionic surfactant Dowfax (manufactured by Dow Chemical Co., Ltd.) dissolved in 550 parts of ion-exchanged water was added, dispersed and emulsified in a flask, and stirred and mixed slowly for 10 minutes. 50 parts of ion-exchanged water in which 6 parts were dissolved was added. Next, after purging the nitrogen in the flask, the solution in the flask was heated with an oil bath to 70 ° C. while stirring, and emulsion polymerization was continued for 5 hours to disperse the anionic resin particles having a solid content of 41%. A liquid (1) was obtained.
The resin particles in the resin particle dispersion (1) had a center particle size of 196 nm, a glass transition temperature of 51.5 ° C., and a weight average molecular weight Mw of 32,400.

[Preparation of resin particle dispersion (2)]
・ Styrene (manufactured by Wako Pure Chemical Industries, Ltd.): 280 parts ・ n-butyl acrylate (manufactured by Wako Pure Chemical Industries, Ltd.): 120 parts ・ β-carboxyethyl acrylate (manufactured by Rhodia Nikka Co., Ltd.): 9 Part A solution prepared by mixing 1.5 parts of the anionic surfactant Dowfax (manufactured by Dow Chemical Co., Ltd.) in 550 parts of ion-exchanged water is dispersed and emulsified in a flask and slowly stirred for 10 minutes. -While mixing, 50 parts of ion-exchanged water in which 0.4 part of ammonium persulfate was dissolved was added. Next, after purging the nitrogen in the flask, the solution in the flask was heated with an oil bath to 70 ° C. while stirring, and emulsion polymerization was continued for 5 hours to disperse the anionic resin particles with a solid content of 42%. A liquid (2) was obtained.
The resin particles in the resin particle dispersion (2) had a center particle size of 150 nm, a glass transition temperature of 53.2 ° C., a weight average molecular weight Mw of 41,000 and a number average molecular weight Mn of 25,000.

[Preparation of Colorant Particle Dispersion (1)]
・ C. I. Pigment Yellow 74 pigment: 30 parts, anionic surfactant (manufactured by NOF Corporation: Nurex R): 2 parts, ion-exchanged water: 220 parts The above ingredients were mixed and mixed with a homogenizer (IKA Ultra Turrax). After the preliminary dispersion, the dispersion process was performed for 15 minutes at a pressure of 245 Mpa using an optimizer (counter-impact collision type wet pulverizer: manufactured by Sugino Machine Co., Ltd.). % Colorant particle dispersion (1) was obtained.

[Preparation of release agent particle dispersion (1)]
Paraffin wax HNP9 (melting temperature 75 ° C .: manufactured by Nippon Seiki Co., Ltd.): 45 parts Cationic surfactant Neogen RK (Daiichi Kogyo Seiyaku Co., Ltd.): 5 parts Ion-exchanged water: 200 parts The mixture is heated to 100 ° C., dispersed with Ultra Turrax T50 (manufactured by IKA), and then dispersed with a pressure discharge type gorin homogenizer. A 0% release agent particle dispersion (1) was obtained.

[Production of Toner Particles (1)]
Resin particle dispersion (1): 106 parts Resin particle dispersion (2): 36 parts Colorant particle dispersion (1): 30 parts Release agent particle dispersion (1): 91 parts In a round stainless steel flask, a solution mixed and dispersed with Ultra Turrax T50 (manufactured by IKA) was obtained.
Next, 0.4 parts of polyaluminum chloride was added to this solution to produce core aggregated particles, and the dispersion operation was continued using an ultra turrax. Further, the solution in the flask was heated to 49 ° C. with stirring in an oil bath for heating and held at 49 ° C. for 45 minutes, and then 36 parts of the resin particle dispersion (1) was added to the core / shell aggregated particles. Produced. Thereafter, 0.5 mol / L aqueous sodium hydroxide solution was added to adjust the pH of the solution to 5.6, and then the stainless steel flask was sealed and heated to 96 ° C. while continuing stirring using a magnetic seal, After maintaining the time, the mixture was cooled to obtain yellow toner particles.

  Next, the toner particles dispersed in the solution were filtered, washed with ion exchange water, and then subjected to solid-liquid separation by Nutsche suction filtration. This was further redispersed in ion exchange water at 40 ° C., and stirred and washed at 300 rpm for 15 minutes. This was repeated five more times, and when the pH of the filtrate was 7.01, the electrical conductivity was 9.8 μS / cm, and the surface tension was 71.1 Nm, solid-liquid separation was performed using No5A filter paper by Nutsche suction filtration. The obtained solid was vacuum dried for 12 hours to obtain toner particles (1) having a volume average particle diameter of 4.5 μm.

(Preparation of silica aggregate)
<Preparation of Silica Aggregate (1)>
[Alkali Catalyst Solution Preparation Step-Preparation of Alkaline Catalyst Solution (1)-]
Put 157.9 parts of methanol and 25.89 parts of 10% ammonia water in a glass reaction vessel equipped with a metal stir bar, dripping nozzle (Teflon (registered trademark) micro tube pump), and thermometer, and stir and mix. As a result, an alkali catalyst solution (1) was obtained.

[Particle Generation Step-Preparation of Silica Particle Suspension-]
Next, the temperature of the alkali catalyst solution (1) was adjusted to 35 ° C., and the alkali catalyst solution (1) was replaced with nitrogen. Thereafter, while stirring the alkaline catalyst solution (1), 28.73 parts of tetramethoxysilane (TMOS) and ammonia water having a catalyst (NH ₃ ) concentration of 3.8% were simultaneously added dropwise at the following supply amount. A suspension of silica particles (silica particle suspension (1)) was obtained. Here, the supply amount of tetramethoxysilane (TMOS) was 5.27 parts / min, and the supply amount of 3.8% ammonia water was 3.18 parts / min. The primary particle size was controlled by adjusting the temperature of the alkaline catalyst solution.
When the particles of the obtained silica particle suspension (1) were measured with the particle size measuring apparatus described above, the volume average particle diameter (D50v) was 150 nm. The volume average particle size corresponds to the primary particle size of the silica aggregate.

[Hydrophobicization treatment process]
The obtained suspension of hydrophilic silica particles (silica particle suspension (1), hydrophilic silica particle dispersion) is dried by spray drying to remove the solvent to obtain hydrophilic silica particle powder. It was.
100 parts of the obtained powder of hydrophilic silica particles is put in a mixer and stirred at 200 rpm while heating to 130 ° C. in a nitrogen atmosphere, and 30 parts of hexamethyldisilazane (HMDS) is added to the powder of hydrophilic silica particles. The solution was dropped and reacted for 20 hours. Then, the powder of the hydrophobic silica particle which was cooled and hydrophobized was obtained. The resulting silica was redispersed with methanol, air-dried to a volatile content of 50 w%, then pressed with a compression molding machine for 5 tons for 60 seconds, dried, and crushed at 5,000 rpm for 30 seconds with a 0.4 L sample mill. As a result, a silica aggregate (1) was obtained. The hydrophobization degree A was controlled by adjusting the hydrophobizing temperature. Further, the difference between the degree of hydrophobicity A and the degree of hydrophobicity B was controlled by adjusting the hydrophobizing time.

<Preparation of silica aggregate (2)>
In the production of the silica aggregate (1), stirring was performed while heating to 130 ° C. in a nitrogen atmosphere, and the reaction of hexamethyldisilazane with the hydrophilic silica particle powder for 20 hours was performed at 115 ° C. for 12 hours. A silica aggregate (2) was prepared in the same manner as in the preparation of the silica aggregate (1) except for the above.

<Preparation of silica aggregate (3)>
In the preparation of the silica aggregate (1), stirring was performed while heating to 130 ° C. in a nitrogen atmosphere, and the reaction of hexamethyldisilazane with the hydrophilic silica particle powder for 20 hours was performed at 100 ° C. for 5 hours. A silica aggregate (3) was prepared in the same manner as in the preparation of the silica aggregate (1) except that the above procedure was performed.

<Preparation of silica aggregate (4)>
In the production of the silica aggregate (1), the silica aggregate (4) was prepared in the same manner as the production of the silica aggregate (1) except that the crushing at 5,000 rpm for 30 seconds was changed to 5,000 rpm for 20 seconds. ) Was made.

<Preparation of silica aggregate (5)>
In the production of the silica aggregate (1), stirring was performed while heating to 130 ° C. in a nitrogen atmosphere, and the reaction of hexamethyldisilazane with the powder of hydrophilic silica particles for 20 hours was performed at 115 ° C. for 9 hours. The silica aggregate (5) was prepared in the same manner as the silica aggregate (1) except that the crushing at 5,000 rpm for 30 seconds was changed to 5,000 rpm for 20 seconds. .

<Preparation of Silica Aggregate (6)>
In the production of the silica aggregate (1), stirring was performed while heating to 130 ° C. in a nitrogen atmosphere, and the reaction of hexamethyldisilazane with the hydrophilic silica particle powder for 20 hours was performed at 100 ° C. for 5 hours. In addition, the silica aggregate (6) was prepared in the same manner as the silica aggregate (1) except that the crushing at 5,000 rpm for 30 seconds was changed to 5,000 rpm for 20 seconds. .

<Preparation of silica aggregate (7)>
In the production of the silica aggregate (1), the silica aggregate (7) was produced in the same manner as the production of the silica aggregate (1) except that the crushing at 5,000 rpm for 30 seconds was changed to 4,000 rpm for 20 seconds. ) Was made.

<Preparation of silica aggregate (8)>
In the production of the silica aggregate (1), stirring was performed while heating to 130 ° C. in a nitrogen atmosphere, and the reaction of hexamethyldisilazane with the hydrophilic silica particle powder for 20 hours was performed at 115 ° C. for 12 hours. In addition, the silica aggregate (8) was prepared in the same manner as the silica aggregate (1) except that the crushing at 5,000 rpm for 30 seconds was changed to 4,000 rpm for 20 seconds. .

<Preparation of silica aggregate (9)>
In the production of the silica aggregate (1), stirring was performed while heating to 130 ° C. in a nitrogen atmosphere, and the reaction of hexamethyldisilazane with the hydrophilic silica particle powder for 20 hours was performed at 100 ° C. for 5 hours. The silica aggregate (9) was prepared in the same manner as the silica aggregate (1) except that the crushing at 5,000 rpm for 30 seconds was changed to 4,000 rpm for 20 seconds. .

<Preparation of Silica Aggregate (10)>
In the preparation of the silica aggregate (1), the temperature of the alkali catalyst solution (1) was changed from 35 ° C. to 75 ° C. to obtain particles having a volume average particle diameter (D50v) of 40 nm, and then increased to 130 ° C. under a nitrogen atmosphere. Stirring while heating, reacting hexamethyldisilazane with hydrophilic silica particle powder for 20 hours, reacting at 115 ° C. for 9 hours, and crushing at 5,000 rpm for 30 seconds. The silica aggregate (10) was prepared in the same manner as the silica aggregate (1) except that the speed was 5,000 rpm for 20 seconds.

<Preparation of Silica Aggregate (11)>
In the production of the silica aggregate (1), the temperature of the alkali catalyst solution (1) was changed from 35 ° C. to 10 ° C. to obtain particles having a volume average particle diameter (D50v) of 600 nm, and then increased to 130 ° C. under a nitrogen atmosphere. Stirring while heating, reacting hexamethyldisilazane with hydrophilic silica particle powder for 20 hours, reacting at 115 ° C. for 9 hours, and crushing at 5,000 rpm for 30 seconds. The silica aggregate (11) was prepared in the same manner as the silica aggregate (1) except that the speed was 5,000 rpm for 20 seconds.

<Preparation of Silica Aggregate (12)>
In the production of the silica aggregate (1), the silica aggregate (12) was produced in the same manner as the production of the silica aggregate (1) except that the crushing at 5,000 rpm for 30 seconds was changed to 10,000 rpm for 30 seconds. ) Was made.

<Preparation of silica aggregate (13)>
In the production of the silica aggregate (3), the silica aggregate (13) was prepared in the same manner as the production of the silica aggregate (3) except that the crushing at 5,000 rpm for 30 seconds was changed to 10,000 rpm for 30 seconds. ) Was made.

<Preparation of silica aggregate (14)>
In the production of the silica aggregate (1), stirring was performed while heating to 130 ° C. in a nitrogen atmosphere, and the reaction of hexamethyldisilazane with the hydrophilic silica particle powder for 20 hours was performed at 135 ° C. for 20 hours. A silica aggregate (14) was prepared in the same manner as in the preparation of the silica aggregate (1) except for the above.

<Preparation of silica aggregate (15)>
In the preparation of the silica aggregate (1), stirring was performed while heating to 130 ° C. in a nitrogen atmosphere, and the reaction of hexamethyldisilazane with the hydrophilic silica particle powder for 20 hours was performed at 97 ° C. for 4 hours. A silica aggregate (15) was prepared in the same manner as in the preparation of the silica aggregate (1) except for the above.

<Preparation of Silica Aggregate (16)>
In the preparation of the silica aggregate (7), stirring was performed while heating to 130 ° C. in a nitrogen atmosphere, and the reaction of hexamethyldisilazane with the powder of hydrophilic silica particles for 20 hours was performed at 135 ° C. for 20 hours. A silica aggregate (16) was prepared in the same manner as in the preparation of the silica aggregate (7) except that the above steps were performed.

<Preparation of silica aggregate (17)>
In the preparation of the silica aggregate (7), stirring was performed while heating at 130 ° C. in a nitrogen atmosphere, and hexamethyldisilazane was reacted with hydrophilic silica particle powder for 20 hours. A silica aggregate (17) was prepared in the same manner as in the preparation of the silica aggregate (7) except that the above procedure was performed.

<Preparation of Silica Aggregate (18)>
In the production of the silica aggregate (1), the silica aggregate (18) was prepared in the same manner as the production of the silica aggregate (1) except that the crushing at 5,000 rpm for 30 seconds was changed to 3,000 rpm for 20 seconds. ) Was made.

<Preparation of silica aggregate (19)>
In the production of the silica aggregate (3), the silica aggregate (19) was prepared in the same manner as the production of the silica aggregate (3) except that the crushing at 5,000 rpm for 30 seconds was changed to 3,000 rpm for 20 seconds. ) Was made.

<Preparation of Silica Aggregate (20)>
In the production of the silica aggregate (1), stirring was performed while heating to 130 ° C. in a nitrogen atmosphere, and the reaction of hexamethyldisilazane with the hydrophilic silica particle powder for 20 hours was performed at 130 ° C. for 2 hours. A silica aggregate (20) was prepared in the same manner as in the preparation of the silica aggregate (1) except that it was used.

<Preparation of silica aggregate (21)>
In the production of the silica aggregate (1), stirring was performed while heating to 130 ° C. in a nitrogen atmosphere, and the reaction of hexamethyldisilazane with the hydrophilic silica particle powder for 20 hours was performed at 100 ° C. for 2 hours. A silica aggregate (21) was prepared in the same manner as in the preparation of the silica aggregate (1) except for the above.

<Preparation of Silica Aggregate (22)>
In the preparation of the silica aggregate (7), stirring was performed while heating to 130 ° C. in a nitrogen atmosphere, and the reaction of hexamethyldisilazane with hydrophilic silica particle powder for 20 hours was performed at 130 ° C. for 2 hours. A silica aggregate (22) was prepared in the same manner as in the preparation of the silica aggregate (7) except that the above procedure was performed.

<Preparation of silica aggregate (23)>
In the preparation of the silica aggregate (7), stirring was performed while heating to 130 ° C. in a nitrogen atmosphere, and the reaction of hexamethyldisilazane with the hydrophilic silica particle powder for 20 hours was performed at 100 ° C. for 2 hours. A silica aggregate (23) was prepared in the same manner as in the preparation of the silica aggregate (7) except that the above procedure was performed.

(Examples 1-11, Comparative Examples 1-12)
<Production of Toner Mixture (1)>
To 100 parts by weight of toner particles (1), 3 parts by weight of silica particles (RY50: manufactured by Nippon Aerosil Co., Ltd.) are added as an external additive, and mixed with a Henschel mixer at 3,600 rpm for 10 minutes to obtain a toner. (1) was obtained.
To 100 parts by weight of toner (1), 0.01 part by weight of silica aggregate (1) was added and mixed with a Henschel mixer at 1,200 rpm for 1 minute to produce toner mixture (1). The obtained toner mixture (1) is prepared with an opening of 100 μm mesh (manufactured by Asada Mesh Co., Ltd., custom-made product) and an opening of 12 μm mesh (made by Asada Mesh Co., Ltd., custom-made product). After air blowing at a blow pressure of 0.2 MPa from a height of 160 mm above the sieve while sucking air at a suction pressure of 5 mmHg on the sieve, the above remaining on the sieve when air is sucked at a suction pressure of 20 mmHg When the weight of the aggregate of the external additive was confirmed and calculated from the ratio to the amount of the charged toner, the amount of silica aggregate (wt%) having a particle size of 12 μm or more and 100 μm or less was 0.01 wt%.

<Toner mixture (2) to (23)>
Toner mixtures (2) to (23) were prepared in the same manner as the toner mixture (1) except that the used toner particles and silica aggregates were changed.

(Manufacture of developer)
Each obtained toner mixture and carrier were put into a V blender so that the ratio of toner: carrier = 5: 95 (weight ratio) in the toner mixture was obtained, and stirred for 20 minutes to obtain a developer.

In addition, the carrier produced as follows was used.
1,000 parts of Mn—Mg ferrite (volume average particle size: 50 μm, manufactured by Powder Tech Co., Ltd., shape factor SF1: 120) were added to a kneader, and a perfluorooctylmethyl acrylate-methyl methacrylate copolymer (polymerization ratio: 20 / 80, Tg: 72 ° C., weight average molecular weight: 72,000, manufactured by Soken Chemical Co., Ltd.] A solution in which 150 parts were dissolved in 700 parts of toluene was added and mixed at room temperature (25 ° C.) for 20 minutes. After heating and drying under reduced pressure, the product was taken out to obtain a coated carrier, and the obtained coated carrier was sieved with a mesh having a mesh opening of 75 μm to remove coarse powder, and the carrier was obtained with a carrier shape factor SF1 of 122. It was.

(Evaluation)
Using the developer obtained in each example, DocuCentre C manufactured by Fuji Xerox Co., Ltd.
olor 400 remodeling machine (image holding body, charging means, exposure means, developing means, transfer means, and fixing means, the charging means applies a voltage to a semiconductive rubber roller near the contact portion with the photoreceptor. This is a means using a charging roller that causes discharge to charge the photosensitive member.) And evaluated for fogging, photosensitive member filming, and transfer maintenance as follows. The results are shown in Table 1.

<Fog evaluation>
Test environment: temperature 32 ° C, humidity 90%
The white portion (portion where there is no toner patch) on the photoconductor was transferred to a tape and measured with a density measuring device X-rite 404A manufactured by X-rite.
The evaluation value was D = (measured value) − (value of the tape only), and the evaluation was performed according to the following criteria.
A: D ≦ 0.01
B: 0.01 <D ≦ 0.02
C: 0.02 <D <0.10
D: 0.10 ≦ D

<Photoconductor filming evaluation (filming evaluation)>
Test environment: temperature 32 ° C, humidity 90%
On a color paper (J paper) manufactured by Fuji Xerox Co., Ltd., adjusted to a toner paste amount of 6 g / m ² at the tip of the image 10 cm, and continuously at a peripheral speed of 2,000 mm / sec. Images were formed on one sheet. Every time 2,000 images were formed, the deposits on the photoreceptor were visually confirmed and evaluated according to the following criteria.
A: Adhering matter cannot be confirmed on the photosensitive member up to 10,000 sheets.
B: No adhering matter can be confirmed on the photoreceptor up to 4,000 sheets.
C: Streaked deposits are confirmed at the time when 4,000 images are formed. However, there is no practical problem.
D: Deposits are present in almost the entire area of the photoreceptor.

<Transfer maintenance evaluation>
Test environment: temperature 32 ° C, humidity 90%
After continuous image formation of 10,000 sheets at a peripheral speed of 2,000 mm / sec of the developer holding member, the toner patch is transferred from the photosensitive member to the intermediate transfer belt, but has not been cleaned yet. The photosensitive member was taken out, and a transparent tape was pressed against the position of the toner patch on the photosensitive member to remove it, thereby recovering the toner that was not transferred. The collected toner was affixed to the white plate together with the tape, and the transferability was visually evaluated by observing the coloring with the toner that was not transferred.
The evaluation criteria are as follows.
A: Coloring with toner cannot be visually confirmed on the white plate.
B: Coloring with toner can be visually confirmed, which is a practical problem.

Claims (10)

Toner for developing electrostatic image, and
Containing a silica aggregate having a particle size of 12 μm or more and 100 μm or less,
Containing the silica aggregate in an amount of 0.01% by weight or more and 0.50% by weight or less based on the electrostatic charge developing toner;
A toner mixture characterized by satisfying the following formulas (1) and (2), where A is the degree of hydrophobicity of the silica aggregate and B is the degree of hydrophobicity after crushing of the silica aggregate:
50 ≦ A ≦ 80 (1)
AB ≦ 5 (2)   The toner mixture according to claim 1, wherein a primary average particle diameter of the silica aggregate is 50 nm or more and 500 nm or less.   An electrostatic charge image developer comprising the toner mixture according to claim 1 and a carrier and a carrier.   A toner cartridge which is detachable from an image forming apparatus and contains the toner mixture according to claim 1.   A developer cartridge containing the electrostatic charge image developer according to claim 3.   A process cartridge comprising a developer holder that contains the electrostatic image developer according to claim 3 and that holds and conveys the electrostatic image developer. An image carrier,
Charging means for charging the image carrier;
Exposure means for exposing the charged image carrier to form an electrostatic latent image on the surface of the image carrier;
Developing means for developing the electrostatic latent image with a developer containing toner to form a toner image;
Transfer means for transferring the toner image from the image carrier to the surface of the transfer target;
Fixing means for fixing the toner image transferred to the surface of the transfer target,
An image forming apparatus, wherein the developer is the toner mixture according to claim 1 or 2, or the electrostatic charge image developer according to claim 3. A latent image forming step of forming an electrostatic latent image on the surface of the image carrier;
A development step of developing the electrostatic latent image formed on the surface of the image carrier with a developer containing toner to form a toner image;
A transfer step of transferring the toner image onto the surface of the transfer target;
Fixing a toner image transferred to the surface of the transfer target,
An image forming method using the toner mixture according to claim 1 or the electrostatic charge image developer according to claim 3 as the developer. The particle diameter is 12 μm or more and 100 μm or less,
A silica aggregate characterized by satisfying the following formulas (1) and (2), where A is the degree of hydrophobicity before crushing and B is the degree of hydrophobicity after crushing.
50 ≦ A ≦ 80 (1)
AB ≦ 5 (2)   The silica aggregate of Claim 9 whose primary average particle diameter is 50 nm or more and 500 nm or less.