CN117742103A - Silica particles, toner, developer, cartridge, image forming apparatus, and image forming method - Google Patents

Abstract

The invention discloses silica particles, toner, developer, cartridge, image forming apparatus, and image forming method. The silica particles have at least one peak in the pore distribution curve after calcination at 350 ℃ in the nitrogen adsorption method in the range of pore diameters of 2nm or less and in the range of more than 2nm and 50nm or less, and D/B is 0.50 or more and 2.50 or less when D and B are the pore volumes in the range of 2nm or less and in the range of 2nm to 25nm or less, respectively, obtained from the pore distribution curve after calcination at 350 ℃ in the nitrogen adsorption method.

Description

Silica particles, toner, developer, cartridge, image forming apparatus, and image forming method

Technical Field

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

Background

JP-A2021-151944 discloses "a silica particle containing a quaternary ammonium salt, wherein the maximum value F of the frequency of the pore diameter of the silica particle before cleaning, which is obtained from the pore distribution curve of the nitrogen adsorption method, is 2nm or less _BEFORE Maximum value F of frequency of pore diameter of 2nm or less in silica particles after cleaning obtained from pore distribution curve of nitrogen adsorption method _AFTER Ratio F of _BEFORE /F _AFTER Is 0.90 to 1.10, and has a maximum value F _BEFORE And a maximum value F of the frequency of the pore diameter of the silica particles after calcination at 600 ℃ to be 2nm or less, which is obtained from the pore distribution curve of the nitrogen adsorption method _SINTERING Ratio F of _SINTERING /F _BEFORE 5 to 20 inclusive.

Japanese patent No. 6968632 discloses "a hydrophobic silica powder characterized by having a degree of hydrophobization of 50% or more, a saturated water content of 4% or less, a nitrogen content of 0.05% or more, and containing 0.1% or more of an amine having a boiling point of 100 ℃ or more". ".

Disclosure of Invention

The present invention addresses the problem of providing silica particles which can improve charge rising properties as compared to the case of silica particles comprising: that is, the silica particles have at least one peak in the pore distribution curve after calcination at 350 ℃ in the nitrogen adsorption method in the range of pore diameters of 2nm or less and in the range of more than 2nm and 50nm or less, and D/B is less than 0.50 when D and B are set as pore volumes in the range of pore diameters of 2nm or less and in the range of 2nm to 25nm, respectively, obtained from the pore distribution curve after calcination at 350 ℃ in the nitrogen adsorption method.

According to a first aspect of the present invention, there is provided silica particles having at least one peak in a pore distribution curve after calcination at 350 ℃ in a nitrogen adsorption method, wherein the pore diameter is 2nm or less and in a range exceeding 2nm and 50nm or less, and wherein the D/B is 0.50 or more and 2.50 or less when D and B are set as pore volumes in a range of 2nm or less and in a range of 2nm to 25nm, respectively, obtained from the pore distribution curve after calcination at 350 ℃ in the nitrogen adsorption method.

According to a second aspect of the present invention, in the silica particles based on the first aspect, the D/B is 0.55 or more and 2.00 or less.

According to a third aspect of the present invention, in the silica particles based on the first or second aspect, the D is 0.10cm ³ Above/g and 1.10cm ³ And/g or less.

According to a fourth aspect of the present invention, the silica particles based on any one of the first to third aspects contain a nitrogen-containing element compound.

According to a fifth aspect of the present invention, in the silica particles based on the fourth aspect, the content of the nitrogen-containing element compound is 0.02 mass% or more and 1.20 mass% or less with respect to the nitrogen content of the silica particles.

According to a sixth aspect of the present invention, in the silica particles according to the fourth or fifth aspect, when a pore volume of 2nm or less as determined from a pore distribution curve before calcination at 350 ℃ by a nitrogen adsorption method is C, a ratio C/D of C to D is 0.05 or more and 0.82 or less.

According to a seventh aspect of the present invention, in the silica particles based on the sixth aspect, the C/D is 0.05 or more and 0.70 or less.

According to an eighth aspect of the present invention, in the silica particles according to any one of the fourth to seventh aspects, when a pore volume of a pore diameter obtained from a pore distribution curve before calcination at 350 ℃ by a nitrogen adsorption method is a pore volume of 2nm to 25nm, a ratio a/B of a to B is 0 to 0.92.

According to a ninth aspect of the present invention, in the silica particles according to any one of the fourth to eighth aspects, a number average particle diameter is 40nm or more and 200nm or less.

According to a tenth aspect of the present invention, in the silica particles based on any one of the fourth to ninth aspects, the nitrogen-containing element compound is at least one selected from the group consisting of a quaternary ammonium salt, a primary amine compound, a secondary amine compound, a tertiary amine compound, an amide compound, an imine compound, and a nitrile compound.

According to an eleventh aspect of the present invention, there is provided a toner for developing an electrostatic charge image, comprising: toner particles; and the silica particles based on any one of the fourth to tenth aspects, which are externally added to the toner particles.

According to a twelfth aspect of the present invention, there is provided an electrostatic charge image developer comprising the toner for electrostatic charge image development based on the eleventh aspect.

According to a thirteenth aspect of the present invention, there is provided a toner cartridge containing the electrostatic charge image developing toner according to the eleventh aspect, the toner cartridge being attached to and detached from an image forming apparatus.

According to a fourteenth aspect of the present invention, there is provided a process cartridge provided with a developing member that accommodates the electrostatic charge image developer based on the twelfth aspect and develops an electrostatic charge image formed on a surface of an image holding body into a toner image by the electrostatic charge image developer, the process cartridge being attached to and detached from an image forming apparatus.

According to a fifteenth aspect of the present invention, there is provided an image forming apparatus including: an image holding body; a charging member that charges a surface of the image holding body; a static charge image forming member that forms a static charge image on a surface of the charged image holding body; a developing member that accommodates the electrostatic charge image developer based on the twelfth aspect and develops an electrostatic charge image formed on a surface of the image holding body into a toner image by the electrostatic charge image developer; a transfer member that transfers the toner image formed on the surface of the image holder onto the surface of a recording medium; and a fixing member that fixes the toner image transferred onto the surface of the recording medium.

According to a sixteenth aspect of the present invention, there is provided an image forming method comprising: a charging step of charging the surface of the image holder; a static charge image forming step of forming a static charge image on the surface of the charged image holder; a developing step of developing an electrostatic charge image formed on a surface of the image holder into a toner image by the electrostatic charge image developer according to the twelfth aspect; a transfer step of transferring the toner image formed on the surface of the image holder onto the surface of a recording medium; and a fixing step of fixing the toner image transferred onto the surface of the recording medium.

(Effect)

According to the first aspect, there can be provided silica particles capable of improving charge rising properties as compared with the following cases: that is, the silica particles have at least one peak in the pore distribution curve after calcination at 350 ℃ in the nitrogen adsorption method in the range of pore diameters of 2nm or less and in the range of more than 2nm and 50nm or less, and the D/B is less than 0.50 when D and B are the pore volumes in the range of pore diameters of 2nm or less and in the range of 2nm to 25nm, respectively, obtained from the pore distribution curve after calcination at 350 ℃ in the nitrogen adsorption method.

According to the second aspect, a silica particle capable of improving charge rising property as compared with the case where D/B is less than 0.55 can be provided.

According to the third aspect, there can be provided silica particles smaller than 0.10cm in D ³ In the case of/g, the charge rising property can be improved.

According to the fourth aspect, a silica particle having excellent charge rising properties as compared with a case where the silica particle does not contain a nitrogen element compound can be provided.

According to the fifth aspect, a silica particle excellent in charge rising property can be provided as compared with the case where the content of the nitrogen-containing element compound is less than 0.02 mass% with respect to the nitrogen content of the silica particle.

According to the sixth aspect, there can be provided silica particles excellent in charge rising property as compared with the case where the ratio C/D of C to D is more than 0.82 when the pore volume of the silica particles, which is obtained by the pore distribution curve before calcination at 350 ℃ by the nitrogen adsorption method and has a pore diameter of 2nm or less, is C, is included.

According to the seventh aspect, a silica particle excellent in charge rising property as compared with the case where C/D exceeds 0.70 can be provided.

According to the eighth aspect, there can be provided silica particles excellent in charge rising property as compared with the case where the ratio a/B of a to B is more than 0.92 when the pore volume of the silica particles is a, the pore volume being 2nm or more and 25nm or less, as determined from the pore distribution curve before calcination at 350 ℃ by the nitrogen adsorption method, and containing a nitrogen element compound.

According to the ninth aspect, there can be provided silica particles excellent in charge rising property even when the number average particle diameter is 40nm or more and 200nm or less, compared with the following cases: specifically, the silica particles contain a nitrogen element-containing compound, and have at least one peak in the pore distribution curve after calcination at 350 ℃ in the nitrogen adsorption method, in the pore diameter range of 2nm or less and in the range of more than 2nm and 50nm or less, respectively, and when the pore volume in the range of 2nm or less and in the range of 2nm to 25nm or more and B is D and B, respectively, as determined from the pore distribution curve after calcination at 350 ℃ in the nitrogen adsorption method, D/B is less than 0.50.

According to the tenth aspect, there can be provided silica particles which contain at least one selected from the group consisting of quaternary ammonium salts, primary amine compounds, secondary amine compounds, tertiary amine compounds, amide compounds, imine compounds, and nitrile compounds, and are excellent in charge rising property as compared with the following cases: specifically, the silica particles contain a nitrogen element compound, and have at least one peak in the pore distribution curve after calcination at 350 ℃ in the nitrogen adsorption method, in the pore diameter range of 2nm or less and in the range of more than 2nm and 50nm or less, respectively, and when the pore volume in the range of 2nm or less and in the range of 2nm to 25nm or more and B is D and B, respectively, as determined from the pore distribution curve after calcination at 350 ℃ in the nitrogen adsorption method, D/B is less than 0.50.

According to the eleventh, twelfth, thirteenth, fourteenth, fifteenth and sixteenth aspects, there can be provided an electrostatic charge image developing toner excellent in charging rising property as compared with the case where the following silica particles are applied as an external additive to the electrostatic charge image developing toner, and an electrostatic charge image developer, a toner cartridge, a process cartridge, an image forming apparatus and an image forming method using the electrostatic charge image developing toner: specifically, the silica particles contain a nitrogen element-containing compound, and have at least one peak in the pore distribution curve after calcination at 350 ℃ in the nitrogen adsorption method, wherein D/B is less than 0.50 when D and B are respectively the pore diameters in the range of 2nm or less and the pore volumes in the range of 2nm to 25nm inclusive, as determined from the pore distribution curve after calcination at 350 ℃ in the nitrogen adsorption method.

Drawings

Fig. 1 is a schematic configuration diagram showing an example of an image forming apparatus according to the present embodiment;

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

Detailed Description

Hereinafter, an embodiment of the present invention will be described. These descriptions and examples are provided to illustrate embodiments and are not intended to limit the scope of the embodiments.

In the present invention, the numerical range indicated by the term "to" means a range including the numerical values before and after the term "to" as the minimum value and the maximum value, respectively.

In the numerical ranges described in the stages of the present invention, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of the numerical range described in another stage. In the numerical ranges described in the present invention, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples.

In the present invention, the term "process" includes not only an independent process but also the term if the process can be achieved even if it cannot be clearly distinguished from other processes.

In the present invention, the embodiments are described with reference to the drawings, but the configuration of the embodiments is not limited to the configuration shown in the drawings. The sizes of the components in the drawings are conceptual, and the relative relationship between the sizes of the components is not limited thereto.

In the present invention, each component may contain a plurality of corresponding substances. In the case where the amounts of the respective components in the composition are mentioned in the present invention, when a plurality of substances corresponding to the respective components are present in the composition, unless otherwise specified, the total amount of the plurality of substances present in the composition is represented.

In the present invention, a plurality of types of particles corresponding to the respective components may be contained. In the case where a plurality of particles corresponding to each component are present in the composition, unless otherwise specified, the particle size of each component represents a value regarding a mixture of the plurality of particles present in the composition.

In the present invention, "(meth) acrylic acid" is a expression containing both acrylic acid and methacrylic acid, and "(meth) acrylate" is a expression containing both acrylate and methacrylate.

In the present invention, the "toner for developing an electrostatic charge image" is also referred to as "toner", the "developer for developing an electrostatic charge image" is also referred to as "developer", and the "carrier for developing an electrostatic charge image" is also referred to as "carrier".

< silica particle >)

The silica particles of the present embodiment contain a nitrogen element-containing compound, and each have at least one peak in a pore distribution curve after calcination at 350 ℃ in a nitrogen adsorption method in a pore diameter range of 2nm or less and in a pore distribution curve exceeding 2nm and 50nm or less, and when the pore volume in a pore distribution curve obtained by calcination at 350 ℃ in a nitrogen adsorption method is D and B in a pore diameter range of 2nm or less and in a pore volume range of 2nm to 25nm, respectively, D/B is 0.50 or more and 2.50 or less.

Hereinafter, fine pores having a pore diameter in a range of 2nm or less are also referred to as micropores, and fine pores having a pore diameter in a range of more than 2nm and 50nm or less or in a range of 2nm or more and 25nm or less are also referred to as mesopores.

The silica particles of the present embodiment can improve the charge rising property. The reason is presumed to be as follows.

The silica particles are used as an additive component or a main component of powder coating materials, cosmetics, rubbers, abrasives, etc., and serve to improve the strength of resins, the fluidity of powders, and to suppress the accumulation, for example.

Since silica particles accumulate static electricity over time due to excessive negative chargeability, there is a decrease in fluidity or the like caused by time. In contrast, the following techniques are available: by adsorbing or reacting the nitrogen element-containing compound on the surface of the silica particles, excessive negative charging is suppressed.

However, when the nitrogen-containing element compound is adsorbed or reacted on the surface of the silica particles, the positive charging property of the nitrogen-containing element compound is strong, and therefore the charging distribution is expanded, and the charging ascending property is reduced.

Therefore, in the silica particles of the present embodiment, at least one peak is formed in the pore distribution curve after calcination at 350 ℃ by the nitrogen adsorption method in the range where the pore diameter is 2nm or less and in the range exceeding 2nm and 50nm or less, respectively. That is, the structure is provided with mesopores and micropores.

Further, the ratio D/B of the pore volume D in the range of 2nm or less and the pore volume B in the range of 2nm or more and 25nm or less, which are obtained from the pore distribution curve after calcination at 350 ℃ by the nitrogen adsorption method, is set in the above range, so that micropores are sufficiently present with respect to mesopores, and the specific surface area of the silica particles is increased.

Therefore, the nitrogen element-containing compound can be present in the mesopores and micropores of the silica particles. Thus, it is considered that the presence of nitrogen-containing element compounds having different charges in the silica particles lowers the dielectric constant of the particles.

Further, the nitrogen-containing element compound is not on the surface of the silica particles, but can be present in a sufficient amount inside the mesopores and micropores of the silica particles, and thus excessive positive charge and detachment of the nitrogen-containing element compound can be suppressed. This also suppresses expansion of the charge distribution.

From the above, it is assumed that: the silica particles of the present embodiment can improve the charge rising property.

The silica particles according to the present embodiment will be described in detail below.

(pore distribution)

In the silica particles of the present embodiment, at least one peak is present in the pore distribution curve after calcination at 350 ℃ by the nitrogen adsorption method in the range where the pore diameter is 2nm or less and in the range exceeding 2nm and 50nm or less, respectively. In other words, the first peak is present in a range where the pore diameter is 2nm or less, and the second peak is present at least in a range where the pore diameter is more than 2nm and 50nm or less.

That is, the silica particles of the present embodiment are silica particles having mesopores and micropores.

Here, at least one peak in the range of the pore diameter represents that the maximum value obtained from the pore distribution curve in which the vertical axis of the nitrogen adsorption method is the volume frequency and the horizontal axis is the pore diameter is 0.005cm ³ At least one peak (maximum value) of/g.nm or more may occur. Wherein, regarding the range of 2nm or less, nitrogen is usedSince the measurable range of the gas adsorption measurement is 1nm or more, 1nm is regarded as the peak top when the volume frequency increases as the pore size decreases.

(pore volume)

When D and B are used as the pore volume in the range of 2nm or less and the range of 2nm or more and 25nm or less, respectively, the D/B is preferably 0.50 or more and 2.50 or less, more preferably 0.55 or more and 2.00 or less, still more preferably 0.60 or more and 1.80 or less, from the viewpoint of improving the charge rising property, as determined by the pore distribution curve after calcination at 350 ℃ by the nitrogen adsorption method.

Pore volumes D and B in the range of 2nm or less and in the range of 2nm to 25nm after calcination at 350 ℃ are pore volumes of silica particles as they are after the adsorbed substances adsorbed on the pores of the silica particles have been removed by calcination. For example, in the case where the nitrogen-containing compound is adsorbed to the pores of the silica particles, the pore volume after the evaporation of the nitrogen-containing compound, which is adsorbed to the pores of the silica particles and blocks a part of the pores, is used. The larger D/B indicates an increase in micropores relative to mesopores. That is, the nitrogen element-containing compound can be adsorbed to at least a part of mesopores and at least a part of micropores of the silica particles. Therefore, the charging ascending property can be improved.

That is, when the pore volume in the range of 2nm or less and the pore volume in the range of 2nm or more and 25nm or less, which are obtained from the pore distribution curve after calcination at 350 ℃ by the nitrogen adsorption method, is D and B, respectively, the silica particles having D/B of 0.50 or more and 2.50 or less are formed as silica particles excellent in charge rising property by containing a nitrogen element compound.

Here, from the viewpoint of improving the charge rising property, the content of the nitrogen-containing element compound is preferably 0.02 mass% or more and 1.45 mass% or less, more preferably 0.1 mass% or more and 1.1 mass% or less, and still more preferably 0.2 mass% or more and 1.1 mass% or less, with respect to the nitrogen content of the silica particles.

The content of the nitrogen-containing element compound (i.e., the nitrogen content relative to the silica particles) was measured under the following conditions using an element analyzer (for example, NCH-22F manufactured by the chemical analysis center, inc.).

Reaction temperature: 830 DEG C

Reduction temperature: 600 DEG C

Standard sample: element quantification standard sample acetanilide.

Further, as a pretreatment for measurement of silica particles to be measured, a treatment for removing impurities such as ammonia from silica particles is performed by drying the silica particles at 100 ℃ for 24 hours or more with a vacuum dryer.

When D is the pore volume in the range of pore diameter of 2nm or less after calcination at 350 ℃, D is preferably 0.10cm ³ Above/g and 1.10cm ³ Preferably less than or equal to/g, more preferably 0.16cm ³ Above/g and 0.80cm ³ Preferably less than or equal to/g, more preferably 0.18cm ³ Above/g and 0.70cm ³ And/g or less.

The pore volume D of the pores having a pore diameter of 2nm or less after calcination at 350 ℃ is the pore volume of the original micropores of the silica particles after the adsorbate adsorbed on the micropores of the silica particles is removed by calcination. When the nitrogen-containing compound is adsorbed to micropores of the silica particles, the volume of the micropores after volatilization of the nitrogen-containing compound is a part of the micropores to be plugged. That is, it means that the nitrogen element compound can be adsorbed inside micropores in at least a part of the silica particles. Therefore, the charging ascending property is improved.

When the pore volume of the pore diameter of 2nm or less obtained from the pore distribution curve of the nitrogen adsorption method before calcination at 350 ℃ is C, the ratio C/D of C to D is preferably 0.05 or more and 0.82 or less, more preferably 0.05 or more and 0.70 or less, and still more preferably 0.05 or more and 0.50 or less.

The pore volume C before calcination at 350 ℃ is the pore volume in a state where the nitrogen-containing element compound is adsorbed on the micropores (i.e., in a state where the nitrogen-containing element compound blocks a part of the micropores).

Further, in particular, the pore volume D having a pore diameter of 2nm or less after calcination at 350℃is set within the above-mentioned range, and the ratio C/D of the pore volume C having a pore diameter of 2nm or less before calcination at 350℃to the pore volume D having a pore diameter of 2nm or less after calcination at 350℃is set within the above-mentioned range, which means that a nitrogen-containing element compound adsorbs a sufficient amount of a nitrogen-containing element compound to at least a part of micropores of the silica particles. Therefore, if the C/D is set within the above range, the charging ascending property is further improved.

When the pore volume of the nitrogen adsorption method, which is obtained from the pore distribution curve before calcination at 350 ℃, is 2nm to 25nm, is a, the ratio a/B of a to B is preferably 0 to 0.92, more preferably 0 to 0.75, still more preferably 0 to 0.60.

Here, A/B is 0 means that A is 0.

The pore volume B after calcination at 350 ℃ is the pore volume of the original mesopores of the silica particles after the adsorbate adsorbed on the mesopores of the silica particles is removed by calcination. When the nitrogen-containing compound is adsorbed on the mesopores of the silica particles, the pore volume of the mesopores after the nitrogen-containing compound is volatilized and removed to block a part of the mesopores.

The pore volume a before calcination at 350 ℃ is the pore volume in a state where the nitrogen-containing compound is adsorbed on the mesopores (i.e., in a state where the nitrogen-containing compound blocks a part of the mesopores).

In addition, setting a/B within the above range means that the nitrogen-containing element compound adsorbs a sufficient amount of the nitrogen-containing element compound on the mesopores of at least a part of the silica particles. Therefore, if a/B is set within the above range, the charging ascending property is further improved.

Here, the calcination at 350 ℃ means that the temperature is raised to 350 ℃ at a temperature raising rate of 10 ℃/min under a nitrogen atmosphere, maintained at 350 ℃ for 3 hours, and cooled to room temperature (25 ℃) at a temperature lowering rate of 10 ℃/min.

(measurement of pore distribution Curve and pore volume by Nitrogen adsorption)

The pore distribution curve of the nitrogen adsorption method was measured as follows.

The silica particles were cooled to a liquid nitrogen temperature (-196 ℃) and nitrogen gas was introduced, and the adsorption amount of nitrogen gas was determined by a constant volume method or a gravimetric method. The pressure of the introduced nitrogen gas was gradually increased, and adsorption isotherms were prepared by plotting the adsorption amounts of nitrogen gas with respect to the respective equilibrium pressures. As the nitrogen adsorption measurement of silica particles, BELSORP manufactured by BEL Co., ltd. In Japan was used. The pore diameter distribution curve is obtained from adsorption isotherms by using the calculation formulas such as BJH method, SF method, DA method, etc., and is expressed as the frequency of the vertical axis and the pore diameter of the horizontal axis. From the obtained pore diameter distribution curve, the cumulative pore volume distribution in terms of volume on the vertical axis and pore diameter on the horizontal axis is obtained.

From the cumulative pore volume distribution obtained, the position of the peak in the range of each pore diameter was confirmed.

Based on the obtained cumulative pore volume distribution, the pore volume in the range of each pore diameter is cumulative, and this is referred to as "pore volume in the range of each pore diameter".

(Structure of silica particles)

Hereinafter, preferred structures of the silica particles and the nitrogen-containing element compound will be described.

The silica particles are preferably silica particles having a silica master batch and a coating structure which coats at least a part of the surface of the silica master batch and which is composed of a reaction product of a silane coupling agent. In the silica particles, it is preferable that the surface of the silica master has micropores and the coating structure has mesopores.

Further, a nitrogen element-containing compound is preferably attached to both micropores and mesopores.

The silane coupling agent is preferably at least one selected from the group consisting of a monofunctional silane coupling agent, a difunctional silane coupling agent, and a trifunctional silane coupling agent, and more preferably a trifunctional silane coupling agent.

Here, the coating structure composed of the reaction product of the silane coupling agent has a lower density than the silica master batch and has a fine pore structure composed of fine pores. In addition, the coating structure composed of the reaction product of the silane coupling agent (in particular, the trifunctional silane coupling agent) has high affinity with the nitrogen element-containing compound. Therefore, the nitrogen element-containing compound enters the inside of the coating structure (i.e., within the pores of the pore structure).

In addition, the nitrogen element-containing compound also enters the inside of micropores (i.e., within micropores of the pore structure) of the silica master batch.

Therefore, it is presumed that: the content of the nitrogen-containing element compound contained in the silica particles becomes relatively large. In addition, the nitrogen element-containing compound is not easily detached.

Since the surface of the silica master batch is negatively charged, a positively charged nitrogen element compound adheres thereto, thereby generating an effect of counteracting excessive negative charging of the silica master batch. Since the nitrogen element-containing compound adheres to the inside of the coating structure (preferably, in the pores of the pore structure) on the surface of the silica particles, the charged distribution of the silica particles is narrowed by canceling the excessive negative charge of the silica master batch without expanding the charged distribution of the silica particles to the positive charged side.

As a result, the charging ascending property is further improved.

Silica masterbatch-

The silica master batch may be dry silica or wet silica.

Examples of the dry silica include fumed silica (fumed silica) obtained by burning a silane compound; deflagration-process silica obtained by explosive combustion of metal silica fume.

Examples of the wet silica include wet silica obtained by neutralization reaction of sodium silicate with an inorganic acid (precipitated silica synthesized/aggregated under alkaline conditions, gel silica synthesized/aggregated under acidic conditions); colloidal silica obtained by making acidic silicic acid basic and polymerizing; sol-gel silica obtained by hydrolysis of organosilane compounds (e.g., alkoxysilanes). The silica masterbatch is preferably sol-gel silica from the viewpoint of improving the charge rising property.

Reaction products of silane coupling agents

The silane coupling agent is preferably a compound free of N (nitrogen element). The silane coupling agent may be represented by the following formula (TA).

Formula (TA) R ¹ _n -Si(OR ² ) _4-n

In the formula (TA), R ¹ Is a saturated or unsaturated aliphatic hydrocarbon group having 1 to 20 carbon atoms or an aromatic hydrocarbon group having 6 to 20 carbon atoms, R ² Is halogen atom or alkyl, n is 1, 2 or 3. When n is 2 or 3, a plurality of R ¹ May be the same group or may be different groups. When n is 1 or 2, a plurality of R ² May be the same group or may be different groups.

As the reaction product of the silane coupling agent, for example, OR in the formula (TA) can be mentioned ² All or part of (a) is replaced by a reaction product of OH groups; OR is carried out ² A reaction product obtained by polycondensation of all or a part of the groups substituted with OH groups with each other; OR is carried out ² And a reaction product obtained by polycondensation of all or a part of the groups substituted with OH groups with SiOH groups of the silica master batch.

R in formula (TA) ¹ The aliphatic hydrocarbon group represented may be any of linear, branched and cyclic, and is preferably linear or branched. The aliphatic hydrocarbon group is preferably a carbon number of 1 to 20, more preferably a carbon number of 1 to 18, still more preferably a carbon number of 1 to 12, and still more preferably a carbon number of 1 to 10. The aliphatic hydrocarbon group may be either saturated or unsaturated, but is preferably a saturated aliphatic hydrocarbon group, more preferably an alkyl group. The hydrogen atom of the aliphatic hydrocarbon group may be substituted with a halogen atom.

Examples of the saturated aliphatic hydrocarbon group include a linear alkyl group (methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, hexadecyl, eicosyl, etc.), a branched alkyl group (isopropyl, isobutyl, isopentyl, neopentyl, 2-ethylhexyl, tert-butyl, tert-amyl, isopentyl, etc.), a cyclic alkyl group (cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, tricyclodecyl, norbornyl, adamantyl, etc.), and the like.

Examples of the unsaturated aliphatic hydrocarbon group include an alkenyl group (vinyl group, 1-propenyl group, 2-butenyl group, 1-hexenyl group, 2-dodecenyl group, pentenyl group and the like), an alkynyl group (ethynyl group, 1-propynyl group, 2-propynyl group, 1-butynyl group, 3-hexynyl group, 2-dodecenyl group and the like), and the like.

R in formula (TA) ¹ The aromatic hydrocarbon group represented is preferably a carbon number of 6 to 20, more preferably a carbon number of 6 to 18, still more preferably a carbon number of 6 to 12, and still more preferably a carbon number of 6 to 10. Examples of the aromatic hydrocarbon group include phenylene, biphenylene, terphenylene (terphenyl), naphthyl, and anthracenyl. The hydrogen atom of the aromatic hydrocarbon group may be substituted with a halogen atom.

R in formula (TA) ² The halogen atom represented may be a fluorine atom, a chlorine atom, a bromine atom, an iodine atom or the like, and is preferably a chlorine atom, a bromine atom or an iodine atom.

R in formula (TA) ² The alkyl group represented is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 8 carbon atoms, and still more preferably an alkyl group having 1 to 4 carbon atoms. Examples of the straight-chain alkyl group having 1 to 10 carbon atoms include methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl. Examples of the branched alkyl group having 3 to 10 carbon atoms include isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, neopentyl, tert-pentyl, isohexyl, sec-hexyl, tert-hexyl, isoheptyl, sec-heptyl, tert-heptyl, isooctyl, sec-octyl, tert-octyl, isononyl, sec-nonyl, tert-nonyl, isodecyl, zhong Guiji, tert-decyl and the like. Examples of the cyclic alkyl group having 3 to 10 carbon atoms include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl and polycyclic (for example, bicyclic, tricyclic and spirocyclic) alkanes obtained by connecting these monocyclic alkyl groups A base. The hydrogen atom of the alkyl group may be substituted with a halogen atom.

N in formula (TA) is 1, 2 or 3, preferably 1 or 2, more preferably 1.

The silane coupling agent represented by the formula (TA) is preferably R ¹ A saturated aliphatic hydrocarbon group having 1 to 20 carbon atoms, R ² A trifunctional silane coupling agent which is a halogen atom or an alkyl group having 1 to 10 carbon atoms and n is 1.

Examples of the trifunctional silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, butyltrimethoxysilane, hexyltrimethoxysilane, n-octyltrimethoxysilane, decyltrimethoxysilane, dodecyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, butyltriethoxysilane, hexyltriethoxysilane, decyltriethoxysilane, dodecyltriethoxysilane, phenyltrimethoxysilane, o-methylphenyl trimethoxysilane, p-methylphenyl trimethoxysilane, phenyltriethoxysilane, benzyltriethoxysilane, decyltrichlorosilane, and phenyltrichlorosilane (R in the formula (TA) above) ¹ A compound which is an unsubstituted aliphatic hydrocarbon group or an unsubstituted aromatic hydrocarbon group; 3-glycidoxypropyl trimethoxysilane, gamma-methacryloxypropyl trimethoxysilane, gamma-mercaptopropyl trimethoxysilane, gamma-chloropropyl trimethoxysilane, gamma-glycidoxypropyl methyldimethoxy silane (R in formula (TA) above ¹ A compound which is a substituted aliphatic hydrocarbon group or a substituted aromatic hydrocarbon group); etc. The trifunctional silane coupling agent may be used alone or in combination of two or more.

As the trifunctional silane coupling agent, an alkyl trialkoxysilane is preferred, and R in the formula (TA) is more preferred ¹ An alkyl group having 1 to 20 carbon atoms (preferably 1 to 15 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 4 carbon atoms, particularly preferably 1 or 2 carbon atoms), and R ² Is carbonAlkyl trialkoxysilane of alkyl group with atomic number of 1-2.

More specifically, at least one trifunctional silane coupling agent selected from the group consisting of alkyltrimethoxysilane and alkyltriethoxysilane having 1 to 20 carbon atoms in the alkyl group is preferable as the silane coupling agent constituting the coating structure on the surface of the silica master batch;

More preferably at least one trifunctional silane coupling agent selected from the group consisting of alkyltrimethoxysilane and alkyltriethoxysilane having 1 to 15 carbon atoms in the alkyl group;

more preferably, at least one trifunctional silane coupling agent selected from the group consisting of alkyltrimethoxysilane and alkyltriethoxysilane having 1 to 8 carbon atoms in the alkyl group;

more preferably, at least one trifunctional silane coupling agent selected from the group consisting of alkyltrimethoxysilane and alkyltriethoxysilane having 1 to 4 carbon atoms in the alkyl group;

particularly preferred is at least one trifunctional silane coupling agent selected from the group consisting of methyltrimethoxysilane, ethyltrimethoxysilane, methyltriethoxysilane and ethyltriethoxysilane.

The coating structure formed of the reaction product of the silane coupling agent is preferably 5 mass% or more and 100 mass% or less, more preferably 7 mass% or more and 25 mass% or less, with respect to the entire silica particle.

Nitrogen-containing compound

The nitrogen-containing compound is a nitrogen-containing compound other than ammonia and a compound that is in a gaseous state at 25 ℃ or lower.

The nitrogen element-containing compound is preferably attached to micropores of the surface of the silica master batch and the inside of mesopores of the coating structure (i.e., the inside of mesopores of the pore structure) composed of the reaction product of the silane coupling agent. The nitrogen element-containing compound may be one kind or two or more kinds.

Examples of the nitrogen-containing compound include at least one selected from the group consisting of quaternary ammonium salts, primary amine compounds, secondary amine compounds, tertiary amine compounds, amide compounds, imine compounds, and nitrile compounds. The nitrogen element-containing compound is preferably a quaternary ammonium salt.

Specific examples of the primary amine compound include phenethylamine, toluidine, catecholamine, and 2,4, 6-trimethylaniline.

Specific examples of the secondary amine compound include dibenzylamine, 2-nitrodiphenylamine, and 4- (2-octylamino) diphenylamine.

Specific examples of the tertiary amine compound include 1, 8-bis (dimethylamino) naphthalene, N-dibenzyl-2-aminoethanol, and N-benzyl-N-methylethanolamine.

Specific examples of the amide compound include N-cyclohexyl-p-toluenesulfonamide, 4-acetamide-1-benzylpiperidine, and N-hydroxy-3- [1- (phenylsulfanyl) methyl-1H-1, 2, 3-triazol-4-yl ] benzamide.

Specific examples of the imine compound include benzophenone imine, 2, 3-bis (2, 6-diisopropylphenylimino) butane, and N, N' - (ethane-1, 2-diyl) bis (2, 4, 6-trimethylaniline).

Specific examples of the nitrile compound include 3-indoleacetonitrile, 4- [ (4-chloro-2-pyrimidinyl) amino ] benzonitrile, and 4-bromo-2, 2-diphenylbutyronitrile.

The quaternary ammonium salt is preferably a compound represented by the following formula (1).

In the formula (1), R ¹ 、R ² 、R ³ R is R ⁴ Each independently represents a hydrogen atom, an alkyl group, an aralkyl group or an aryl group, X ^- Representing anions. Wherein R is ¹ 、R ² 、R ³ R is R ⁴ At least one of which represents an alkyl group, an aralkyl group or an aryl group. R is R ¹ 、R ² 、R ³ R is R ⁴ May be linked to form an aliphatic ring, an aromatic ring or a heterocyclic ring. Here, the alkyl group, the aralkyl group, and the aryl group may have a substituent.

As R ¹ ～R ⁴ Examples of the alkyl group include a linear alkyl group having 1 to 20 carbon atoms and a branched alkyl group having 3 to 20 carbon atoms. Examples of the linear alkyl group having 1 to 20 carbon atoms include methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, and n-hexadecyl. Examples of the branched alkyl group having 3 to 20 carbon atoms include isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, neopentyl, tert-pentyl, isohexyl, sec-hexyl, tert-hexyl, isoheptyl, sec-heptyl, tert-heptyl, isooctyl, sec-octyl, tert-octyl, isononyl, sec-nonyl, tert-nonyl, isodecyl, zhong Guiji, tert-decyl and the like.

As R ¹ ～R ⁴ The alkyl group is preferably an alkyl group having 1 to 15 carbon atoms such as methyl, ethyl, butyl, and tetradecyl.

As R ¹ ～R ⁴ Examples of the aralkyl group include aralkyl groups having 7 to 30 carbon atoms. Examples of the aralkyl group having 7 to 30 carbon atoms include benzyl, phenylethyl, phenylpropyl, 4-phenylbutyl, phenylpentyl, phenylhexyl, phenylheptyl, phenyloctyl, phenylnonyl, naphthylmethyl, naphthylethyl, anthrylmethyl, phenyl-cyclopentylmethyl and the like.

As R ¹ ～R ⁴ The aralkyl group is preferably an aralkyl group having 7 to 15 carbon atoms such as benzyl, phenylethyl, phenylpropyl, and 4-phenylbutyl.

As R ¹ ～R ⁴ Examples of the aryl group include aryl groups having 6 to 20 carbon atoms. Examples of the aryl group having 6 to 20 carbon atoms include phenyl, pyridyl, and naphthyl.

As R ¹ ～R ⁴ The aryl group represented is preferably an aryl group having 6 to 10 carbon atoms such as a phenyl group.

As R ¹ 、R ² 、R ³ R is R ⁴ Examples of the ring formed by connecting two or more of these compounds to each other include alicyclic rings having 2 or more and 20 or less carbon atoms, heterocyclic amines having 2 or more and 20 or less carbon atoms, and the like.

R ¹ 、R ² 、R ³ R is R ⁴ Each of which may independently have a substituent. Examples of the substituent include a nitrile group, a carbonyl group, an ether group, an amide group, a siloxane group, a silyl group, and an alkoxysilane group.

R ¹ 、R ² 、R ³ R is R ⁴ Preferably, each independently represents an alkyl group having 1 to 16 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms.

X ^- The anions represented may be either organic anions or inorganic anions.

Examples of the organic anions include polyfluoroalkyl sulfonate ion, polyfluoroalkyl carboxylate ion, tetraphenyl borate ion, aromatic carboxylate ion, and aromatic sulfonate ion (1-naphthol-4-sulfonate ion, etc.).

As inorganic anions, mention may be made of OH ^- 、F ^- 、Fe(CN) ₆ ^3- 、Cl ^- 、Br ^- 、NO ₂ ^- 、NO ₃ ^- 、CO ₃ ^2- 、PO ₄ ^3- 、SO ₄ ^2- Etc.

Examples of the inorganic anion include anions containing molybdenum element such as molybdate ion.

The anion containing molybdenum element is preferably a molybdate ion, more preferably a molybdate ion having molybdenum of 4-valent or 6-valent, and still more preferably a molybdate ion having molybdenum of 6-valent. As the molybdate ion, moO is particularly preferable ₄ ^2- 、Mo ₂ O ₇ ^2- 、Mo ₃ O ₁₀ ^2- 、Mo ₄ O ₁₃ ^2- 、Mo ₇ O ₂₄ ^2- 、Mo ₈ O ₂₆ ^4- 。

From the viewpoint of improving the charge rising property, the compound represented by formula (1) is preferably 18 to 35 total carbon atoms, more preferably 20 to 32 total carbon atoms.

The following examples illustrate compounds represented by formula (1). The present embodiment is not limited thereto.

In particular, from the viewpoint of improving the charge rising property, the nitrogen-containing element compound is preferably a nitrogen-containing element compound containing molybdenum element (hereinafter, also referred to as molybdenum-containing nitrogen element compound). Specifically, the molybdenum-nitrogen-containing compound is preferably at least one selected from the group consisting of a quaternary ammonium salt containing molybdenum element, and a mixture of a quaternary ammonium salt and a metal oxide containing molybdenum element, and more preferably a quaternary ammonium salt containing molybdenum element.

In the quaternary ammonium salt containing molybdenum element, the bond between the anion containing molybdenum element and the quaternary ammonium cation is strong, so that the charge distribution maintenance property is high, and the charge rising property is further improved.

As the quaternary ammonium salt containing molybdenum element, [ N ] ⁺ (CH) ₃ (C ₁₄ C ₂₉ ) ₂ ] ₄ Mo ₈ O ₂₈ ^4- 、[N ⁺ (C ₄ H ₉ ) ₂ (C ₆ H ₆ ) ₂ ] ₂ Mo ₂ O ₇ ^2- 、[N ⁺ (CH ₃ ) ₂ (CH ₂ C ₆ H ₆ )(CH ₂ ) ₁₇ CH ₃ ] ₂ MoO ₄ ^2- 、[N ⁺ (CH ₃ ) ₂ (CH ₂ C ₆ H ₆ )(CH ₂ ) ₁₅ CH ₃ ] ₂ MoO ₄ ^2- And quaternary ammonium isosolybdate.

In particular, as the quaternary ammonium salt containing molybdenum element, a compound having CAS registry number 117342-25-3 is particularly preferable. Compounds with CAS registry numbers 117342-25-3 are also referred to as TP-415 and 1-Tetradecanaminium, N, N-dimethyl-N-tetradecyl-, hexa- μ -oxotetra- μ 3-oxodi- μ 5-oxotetradecaoxo amammolybdate (4-) (4:1).

Examples of the metal oxide containing molybdenum element include molybdenum oxide (molybdenum trioxide, molybdenum dioxide, mo ₉ O ₂₆ ) Alkali metal molybdate (lithium molybdate, sodium molybdate, potassium molybdate, etc.), molybdenum alkaline earth metal salt (magnesium molybdate, calcium molybdate, etc.), other composite oxide (Bi) ₂ O ₃ ·2MoO ₃ 、γ-Ce ₂ Mo ₃ O ₁₃ Etc.).

The nitrogen element-containing compound is detected when the silica particles are heated in a temperature range of 300 ℃ to 600 ℃. The nitrogen element-containing compound can be detected by heating at 300 ℃ or higher and 600 ℃ or lower in an inert gas, for example, using a furnace-type falling thermal decomposition gas chromatograph mass spectrometer using He as a carrier gas. Specifically, 0.1mg to 10mg of silica particles are introduced into a pyrolysis gas chromatograph mass spectrometer, and whether or not a nitrogen element compound is contained is confirmed based on the MS spectrum of the detected peak. Examples of the component produced from the silica particles containing the nitrogen element compound by thermal decomposition include a primary amine, secondary amine, tertiary amine or aromatic nitrogen compound represented by the following formula (2). R of formula (2) ¹ 、R ² R is R ³ Respectively with R of formula (1) ¹ 、R ² R is R ³ Meaning the same. When the nitrogen element-containing compound is a quaternary ammonium salt, a part of the side chain is detached by thermal decomposition at 600 ℃.

Here, when a molybdenum-containing compound is used as the nitrogen-containing compound, the ratio (Mo/Si) of Net intensity of the molybdenum element to Net intensity of the silicon element measured by fluorescence X-ray analysis is preferably 0.014 or more and 1.20 or less, more preferably 0.10 or more and 1.10 or less, and still more preferably 0.20 or more and 1.10 or less, from the viewpoint of improving charge rising property.

From the viewpoint of improving the charge rising property, the Net strength of the molybdenum element is preferably 5 to 150 to 10 to 135kcps, 25 to 135 kcps.

The Net strength of molybdenum element and silicon element was measured as follows.

The silica particles were compressed by using a compression molding machine for about 0.5g under pressure for 60 seconds at a load of 6t, thereby producing a disk having a diameter of 50mm and a thickness of 2 mm. The disk was used as a sample, and qualitative and quantitative elemental analysis was performed using a scanning fluorescent X-ray analyzer (XRF-1500, manufactured by Shimadzu corporation) under the following conditions to obtain Net intensities (units: kilo counts per second, kcps) of molybdenum element and silicon element, respectively.

Guan Dianya: 40kV (kilovolt)

Guan Dianliu: 90mA

Area measured (analytical diameter): diameter of/>

Measurement time: 30 minutes

To the cathode: rhodium

The extraction amount X of the nitrogen-containing element compound extracted from the silica particles with the ammonia/methanol mixed solution is preferably 0.1 mass% or more with respect to the silica particles. And, the extraction amount X of the nitrogen-containing element compound extracted from the silica particles with the ammonia/methanol mixed solution and the extraction amount Y of the nitrogen-containing element compound extracted from the silica particles with water preferably satisfy Y/X < 0.3.

The above-mentioned relationship indicates that the nitrogen-containing element compound contained in the silica particles is hardly dissolved in water, that is, hardly adsorbs moisture in air. Therefore, the above relationship results in narrowing of the charged distribution of silica particles and excellent maintenance of the charged distribution.

The extraction amount X is preferably 0.25 mass% or more relative to the silica particles. The upper limit of the extraction amount X is, for example, 6.5 mass% or less. The ratio Y/X of the extraction amount X to the extraction amount Y is desirably 0.

The extraction amount X and the extraction amount Y were measured by the following methods.

The silica particles were analyzed at 400℃by a thermogravimetric/mass spectrometry device (for example, a gas chromatograph mass spectrometer manufactured by NETZSCH Japan Co., ltd.), and the mass fraction of the compound having a hydrocarbon having 1 or more carbon atoms covalently bonded to the nitrogen atom was measured and integrated with respect to the silica particles, and was set as W1.

To 30 parts by mass of an ammonia/methanol solution (ammonia/methanol mass ratio=1/5.2, manufactured by Sigma-Aldrich) having a liquid temperature of 25 ℃, 1 part by mass of silica particles was added, and after 30 minutes of ultrasonic treatment, the silica powder and the extract were separated. The separated silica particles were dried at 100℃for 24 hours by a vacuum dryer, and the mass fraction of the compound having a hydrocarbon having 1 or more carbon atoms covalently bonded to a nitrogen atom was measured at 400℃by a thermogravimetric/mass spectrometry analysis device, relative to the silica particles, and was calculated as W2.

1 part by mass of silica particles was added to 30 parts by mass of water at a liquid temperature of 25℃and subjected to ultrasonic treatment for 30 minutes, followed by separation of the silica particles and the extract. The separated silica particles were dried at 100℃for 24 hours by a vacuum dryer, and the mass fraction of the compound having a hydrocarbon having 1 or more carbon atoms covalently bonded to a nitrogen atom was measured at 400℃by a thermogravimetric/mass spectrometry analysis device, relative to the silica particles, and was calculated as W3.

The extraction amount x=w1-W2 is calculated from W1 and W2.

The extraction amount y=w1-W3 is calculated from W1 and W3.

Hydrophobization of structures

In the silica particles of the present embodiment, a hydrophobizing structure (a structure obtained by treating silica particles with a hydrophobizing agent) may be attached to a coating structure of a reaction product of a silane coupling agent.

As the hydrophobizing agent, for example, an organosilicon compound is used. Examples of the organosilicon compound include the following compounds.

Alkoxy silane compounds or halogenated silane compounds having a lower alkyl group such as methyltrimethoxysilane, dimethyldimethoxysilane, trimethylchlorosilane, and trimethylmethoxysilane.

Vinyl alkoxysilane compounds such as vinyltrimethoxysilane and vinyltriethoxysilane.

Alkoxysilane compounds having an epoxy group such as 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyl methyldimethoxysilane, 3-glycidoxypropyl trimethoxysilane, 3-glycidoxypropyl methyldiethoxysilane, and 3-glycidoxypropyl triethoxysilane.

Alkoxysilane compounds having a styryl group such as p-styryltrimethoxysilane and p-styryltriethoxysilane.

Aminoalkyl-containing alkoxysilane compounds such as N-2- (aminoethyl) -3-aminopropyl methyldimethoxy silane, N-2- (aminoethyl) -3-aminopropyl trimethoxy silane, 3-aminopropyl triethoxy silane, 3-triethoxysilyl-N- (1, 3-dimethyl-butylene) propylamine, and N-phenyl-3-aminopropyl trimethoxy silane.

Alkoxysilane compounds having an isocyanate alkyl group such as 3-isocyanatopropyl trimethoxysilane and 3-isocyanatopropyl triethoxysilane.

Silane compounds such as hexamethyldisilazane and tetramethyldisilazane.

From the viewpoints of narrowing the charge distribution and maintaining the charge distribution, the silica particles preferably have the following characteristics.

Average roundness, average primary particle diameter, number particle size distribution index-

The average roundness of the silica particles of the present embodiment is preferably 0.80 to 1.00, more preferably 0.85 to 1.00, and even more preferably 0.88 to 1.00.

The number average particle diameter of the silica particles of the present embodiment is preferably 20nm to 200nm, more preferably 20nm to 80nm, and still more preferably 20nm to 60 nm.

The number particle size distribution index of the silica particles of the present embodiment is preferably 1.1 to 2.0, more preferably 1.15 to 1.6.

If the number average particle diameter and the number particle size distribution index of the silica particles are within the above-mentioned ranges, the specific surface area is large and excessive electrification is likely to occur, but even if the number average particle diameter and the number particle size distribution index of the silica particles of the present embodiment are within the above-mentioned ranges, the electrification distribution is narrowed and the electrification ascending property is improved.

The average roundness, number average particle diameter, and number particle size distribution index of the silica particles were measured as follows.

An energy-dispersive X-ray analysis device (EDX device) (EMAX evaluation X-Max 80mm manufactured by horiba, ltd.) was used ² ) Scanning Electron Microscope (SEM) (Hitachi, new technology, S-4800) of (Hitachi, ltd.) and the toner was photographed at a magnification of 4 ten thousand times. By EDX analysis, 200 silica particles were determined from within one field of view based on the presence of N element and Si element. Images of 200 silica particles were analyzed using image processing analysis software WinRof (Sangu Co., ltd.).

The circle equivalent diameter, area and circumference of each primary particle image were obtained, and the roundness=4pi× (area of particle image)/(circumference of particle image) was also obtained ² 。

In the distribution of roundness, the roundness calculated from the smaller side to be 50% integrated is set as the average roundness.

In the distribution of the equivalent circle diameters, the equivalent circle diameters which are 50% of the total number of the diameters from the small diameter side are set as the number average particle diameter.

In the distribution of the circle equivalent diameter, the number of particles was calculated by obtaining a number particle size distribution index= (D84/D16) with D16 being the particle size of 16% as the sum of the diameters from the small diameter side and D84 being the particle size of 84% as the sum of the diameters ^0.5 。

Degree of hydrophobization-

The silica particles of the present embodiment preferably have a degree of hydrophobization of 10% to 60%, more preferably 20% to 55%, still more preferably 28% to 53%.

The method for measuring the degree of hydrophobicity of the silica particles is as follows.

To 50ml of deionized water, 0.2 mass% of silica particles was added, and methanol was added dropwise from a burette while stirring with a magnetic stirrer, and the mass fraction of methanol in the methanol-water mixed solution at the end of the precipitation of the total amount of the sample was determined as the degree of hydrophobization.

Volume resistivity-

The volume resistivity R of the silica particles of the present embodiment is preferably 1.0×10 ⁷ Omega cm or more and 1.0X10 ^12.5 Omega cm or less, more preferably 1.0X10 ^7.5 Omega cm or more and 1.0X10 ¹² Omega cm or less, more preferably 1.0X10 ⁸ Omega cm or more and 1.0X10 ^11.5 Omega cm or less, more preferably 1.0X10 ⁹ Omega cm or more and 1.0X10 ¹¹ Omega cm or less. The volume resistivity R of the silica particles can be adjusted according to the content of the nitrogen-containing element compound.

In the silica particles of the present embodiment, when Ra and Rb are used as the volume resistivity before and after calcination at 350 ℃, the ratio Ra/Rb is preferably 0.01 to 0.8, more preferably 0.015 to 0.6.

The volume resistivity Ra (meaning the same as the volume resistivity R) of the silica particles of the present embodiment before calcination at 350 ℃ is preferably 1.0×10 ⁷ Omega cm or more and 1.0X10 ^12.5 Omega cm or less, more preferably 1.0X10 ^7.5 Omega cm or more and 1.0X10 ¹² Omega cm or less, more preferably 1.0X10 ⁸ Omega cm or more and 1.0X10 ^11.5 Omega cm or less, more preferably 1.0X10 ⁹ Omega cm or more and 1.0X10 ¹¹ Omega cm or less.

Calcination at 350℃means heating to 350℃at a heating rate of 10℃per minute under nitrogen atmosphere, holding at 350℃for 3 hours, and cooling to room temperature (25 ℃) at a cooling rate of 10℃per minute.

The volume resistivity of the silica particles was measured at a temperature of 20℃and a relative humidity of 50% as follows.

Is configured with 20cm ² The silica particles are placed on the surface of the circular jig of the electrode plate so as to have a thickness of about 1mm to 3mm, thereby forming a silica particle layer. 20cm of the silica particle layer was placed thereon ² To sandwich the silica particle layer, and to eliminate the gaps between the silica particles, a pressure of 0.4MPa was applied to the electrode plate. The thickness L (cm) of the silica particle layer was measured. A frequency of 10 was obtained by an impedance analyzer (manufactured by Solartron Analytical Co.) connected to both electrodes above and below the silica particle layer ^-3 Hz above and 10 ⁶ Nyquist plot in the range below Hz. The three resistance components, namely, the bulk resistance, the particle interface resistance, and the electrode contact resistance, were assumed to exist, and the three resistance components were fitted to an equivalent circuit to determine the bulk resistance R (Ω). The volume resistivity ρ (Ω·cm) of the silica particles is calculated from the volume resistance R (Ω) and the thickness L (cm) of the silica particle layer by the formula ρ=r/L.

Solid Nuclear Magnetic Resonance (NMR) Spectroscopy

From the viewpoint of improving the charge rising property, the silica particles of the present embodiment preferably satisfy the following embodiment (a).

Mode (a): in a 29Si solid state Nuclear Magnetic Resonance (NMR) spectrum (hereinafter, referred to as "Si-CP/MAS NMR spectrum") based on a cross polarization/magic angle spinning (CP/MAS) method, a ratio Cc/Dd of an integrated value Cc of a signal observed in a range of-50 ppm or more and-75 ppm or less to an integrated value Dd of a signal observed in a range of-90 ppm or more and-120 ppm or less is 0.10 or more and 0.75 or less.

The Si-CP/MAS NMR spectrum was obtained by performing nuclear magnetic resonance spectroscopy under the following conditions.

Beam splitter: AVANCE300 (Bruker company)

Resonance frequency: 59.6MHz

Measurement core: ²⁹ Si

assay: CPMAS (using Bruker Corp. Standard pulse sequence) cp.av

Latency: 4 seconds

Contact time: 8 ms of

Cumulative number of times: 2048 times

Measurement temperature: room temperature (actual measurement 25 ℃ C.)

Observation center frequency: 3975.72Hz

MAS rotation speed: 7.0mm-6kHz

Reference substance: hexamethylcyclotrisiloxane

The ratio Cc/Dd is preferably 0.10 or more and 0.75 or less, more preferably 0.12 or more and 0.45 or less, and still more preferably 0.15 or more and 0.40 or less.

When the integrated value of all signals of the Si-CP/MAS NMR spectrum is set to 100%, the ratio (Signal ratio) of the integrated value Cc of the Signal observed in the range of the chemical shift of-50 ppm or more and-75 ppm or less is preferably 5% or more, more preferably 7% or more. The upper limit of the proportion of the integrated value Cc of the signal is, for example, 60% or less.

The mode (a) is a mode having a low-density coating structure capable of adsorbing a sufficient amount of a nitrogen-containing element compound on at least a part of the surface of the silica particles. The low-density coating structure is, for example, a fine pore structure composed of a reaction product of a trifunctional silane compound, for example, siO _2/3 CH ₃ A layer.

OH group content-

The OH group content of the silica particles of the present embodiment is preferably 0.05/nm ² Above and 6/nm ² Hereinafter, more preferably 0.1/nm ² Above and 5.5/nm ² Hereinafter, more preferably 0.15/nm ² Above and 5/nm ² Hereinafter, it is more preferably 0.2/nm ² Above and 4/nm ² Hereinafter, it is particularly preferably 0.2/nm ² Above and 3/nm ² The following is given.

The OH group content of the silica particles was measured by the Seers method as follows.

1.5g of silica particles was added to a 50g of water/50 g of ethanol mixed solution, and stirred with an ultrasonic homogenizer for 2 minutes, thereby preparing a dispersion. 1.0g of a 0.1mol/L aqueous hydrochloric acid solution was added dropwise while stirring at 25℃to obtain a test solution. The test solution was fed into an automatic titration apparatus, and potentiometric titration was performed using a sodium hydroxide aqueous solution of 0.01mol/L, thereby preparing a differential curve of the titration curve. The titration amount of the greatest titration amount of the 0.01mol/L sodium hydroxide aqueous solution in the inflection point of the differential value of the titration curve being more than 1.8 is set as E.

The surface silanol group density ρ (individual/nm) of the silica particles was calculated according to the following formula ² ) And this was set as the OH group amount of the silica particles.

The formula: ρ= ((0.01×e-0.1) ×na/1000)/(mxs) _BET ×10 ¹⁸ )

E: the differential value of the titration curve is the titration amount with the largest titration amount of 0.01mol/L sodium hydroxide aqueous solution in the inflection point with the differential value of more than 1.8; NA: a Fu Jiade roconstant; m: silica particle amount (1.5 g); s is S _BET : BET specific surface area (m ² /g) (equilibrium relative pressure set to 0.3).

(method for producing silica particles)

An example of a method for producing silica particles includes: a first step of forming a coating structure composed of a reaction product of a silane coupling agent on at least a part of the surface of a silica master batch; and a second step of attaching a nitrogen element compound to the coating structure. The present production method may further include a third step of subjecting the silica master batch having the coating structure to a hydrophobization treatment after or during the second step. The above steps are described in detail below.

Silica masterbatch-

The silica master batch is prepared, for example, by the following step (i).

Step (i): and granulating the silica master batch by a sol-gel method to obtain a silica master batch suspension.

The step (i) is preferably a sol-gel method including the steps of: a base catalyst solution preparation step of preparing a base catalyst solution containing a base catalyst in a solvent containing an alcohol; and a silica masterbatch production step of producing silica masterbatch by supplying tetraalkoxysilane and a base catalyst to the base catalyst solution.

The base catalyst solution preparation step is preferably a step of preparing a solvent containing alcohol and mixing the solvent with a base catalyst to obtain a base catalyst solution.

The solvent containing the alcohol may be a single solvent of the alcohol or may be a mixed solvent of the alcohol and other solvents. Examples of the alcohol include lower alcohols such as methanol, ethanol, n-propanol, isopropanol, and butanol. Examples of the other solvent include water; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.; cellosolves such as methyl cellosolve, ethyl cellosolve, butyl cellosolve and cellosolve acetate; ethers such as dioxane and tetrahydrofuran; etc. In the case of the mixed solvent, the proportion of the alcohol is preferably 80% by mass or more, more preferably 85% by mass or more.

The base catalyst is a catalyst for promoting the reaction (hydrolysis reaction and condensation reaction) of tetraalkoxysilane, and examples thereof include ammonia, urea, monoamine and the like, and particularly preferably ammonia.

The concentration of the base catalyst in the base catalyst solution is preferably 0.5mol/L or more and 1.5mol/L or less, more preferably 0.6mol/L or more and 1.2mol/L or less, and still more preferably 0.65mol/L or more and 1.1mol/L or less.

The silica masterbatch production step is a step of producing silica masterbatch by supplying tetraalkoxysilane and a base catalyst to a base catalyst solution, respectively, and allowing the tetraalkoxysilane to react (hydrolysis reaction and condensation reaction) in the base catalyst solution.

In the silica masterbatch production step, after the core particles are produced by the reaction of the tetraalkoxysilane during the initial period of supply of the tetraalkoxysilane (core particle production stage), the silica masterbatch is produced by the growth of the core particles (core particle growth stage).

Examples of the tetraalkoxysilane include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, and the like. From the viewpoint of controllability of reaction rate or uniformity of shape of the silica master batch produced, tetramethoxysilane or tetraethoxysilane is preferable.

Examples of the base catalyst to be supplied to the base catalyst solution include, for example, ammonia, urea, monoamine, and other base catalysts, and ammonia is particularly preferred. The base catalyst to be supplied together with the tetraalkoxysilane and the base catalyst previously contained in the base catalyst solution may be of the same kind or different kinds, but are preferably of the same kind.

The tetraalkoxysilane and the base catalyst may be supplied to the base catalyst solution in a continuous or intermittent manner.

In the silica masterbatch production step, the temperature of the alkali catalyst solution (temperature at the time of supply) is preferably 5 ℃ or higher and 50 ℃ or lower, more preferably 15 ℃ or higher and 45 ℃ or lower.

The silica master batch is obtained through the above procedures.

In order to obtain silica particles having peaks in the range of pore diameters of 2nm or less after calcination at 350 ℃ (specifically, silica master batch having micropores on the surface), it is preferable to perform an operation of reducing the amount of water in the alkali catalyst solution after granulation. In the silica masterbatch production step, the amount of water in the base catalyst solution is preferably 1 mass% or more and 16 mass% or less at the point when the supply of the tetraalkoxysilane and the base catalyst to the base catalyst solution is completed. The amount of water in the base catalyst solution at the point when the supply of the tetraalkoxysilane and the base catalyst is completed is preferably 1% by mass or more and 10% by mass or less, more preferably 1% by mass or more and 6% by mass or less.

In the silica master batch production step, silica master batch is produced by a reaction (hydrolysis reaction and condensation reaction) of tetraalkoxysilane in a base catalyst solution, and the amount of water in the base catalyst solution is set to an amount of water that suppresses the hydrolysis reaction of tetraalkoxysilane, whereby silica master batch having micropores on the surface can be obtained.

Specifically, the hydrolysis reaction of the tetraalkoxysilane is controlled by adjusting the amount of water in the base catalyst solution before the tetraalkoxysilane is supplied, the amount of the base catalyst supplied, and the amount of water contained in the base catalyst.

For example, the concentration of the base catalyst in the aqueous base catalyst solution to be supplied may be increased or the amount of the base catalyst to be supplied may be decreased while the tetraalkoxysilane and the base catalyst are being supplied to the base catalyst solution. Thus, in the latter half of the reaction of the tetraalkoxysilane, the hydrolysis reaction of the tetraalkoxysilane is suppressed, and micropores can be formed only on the surface of the silica master batch.

First procedure-

The first step is, for example, the following steps: and adding a silane coupling agent into the silica master batch suspension, and enabling the silane coupling agent to react on the surface of the silica master batch to form a coating structure formed by the reaction product of the silane coupling agent.

The reaction of the silane coupling agent is carried out, for example, as follows: after the silane coupling agent is added to the silica master batch suspension, the suspension is heated while stirring. Specifically, for example, the suspension is heated to 40 ℃ or higher and 70 ℃ or lower, and a silane coupling agent is added thereto and stirred. The time for continuing the stirring is preferably 10 minutes to 24 hours, more preferably 60 minutes to 420 minutes, still more preferably 80 minutes to 300 minutes.

Second procedure-

The second step is a step of attaching a nitrogen element-containing compound to the micropores (mesopores) of the coating structure formed by the reaction product of the silane coupling agent.

Through the second step, the nitrogen element compound is attached to the pores (mesopores) of the coating structure and the micropores formed in the silica master batch.

In the second step, for example, a nitrogen element-containing compound is added to the silica master batch suspension after the reaction of the silane coupling agent, and the mixture is stirred while maintaining the liquid temperature in a temperature range of 20 ℃ to 50 ℃. Here, the nitrogen-containing element compound may be added to the silica particle suspension in the form of an alcohol solution containing the nitrogen-containing element compound. The alcohol may be the same type as the alcohol contained in the silica master batch suspension, or may be different types, but is more preferably the same type. In the alcohol solution containing the nitrogen element compound, the concentration of the nitrogen element compound is preferably 0.05% by mass or more and 10% by mass or less, more preferably 0.1% by mass or more and 6% by mass or less.

Third procedure-

The third step is a step of further attaching a hydrophobizing structure to a coating structure composed of a reaction product of a silane coupling agent. The third step is a hydrophobization step performed after or during the second step. The hydrophobizing agent forms a hydrophobized layer by reacting the functional groups of the hydrophobizing agent with each other and/or with the OH groups of the silica master batch.

In the third step, for example, a nitrogen element-containing compound is added to the silica master batch suspension after the reaction of the silane coupling agent, followed by the addition of the hydrophobizing agent. In this case, the suspension is preferably stirred and heated. For example, the suspension is heated to 40 ℃ or higher and 70 ℃ or lower, and a hydrophobizing agent is added thereto and stirred. The time for continuing the stirring is preferably 10 minutes to 24 hours, more preferably 20 minutes to 120 minutes, still more preferably 20 minutes to 90 minutes.

Drying procedure-

The drying step of removing the solvent from the suspension is preferably performed after or during the second or third step. Examples of the drying method include thermal drying, spray drying, and supercritical drying.

The spray drying can be performed by a known method using a spray dryer (disk rotation type, nozzle type, etc.). For example, the silica particle suspension is sprayed in a hot air stream at a rate of 0.2 liters/hour or more and 1 liter/hour or less. The temperature of the hot air is preferably in the range of 70 ℃ to 400 ℃ inclusive and 40 ℃ to 120 ℃ inclusive in the inlet temperature of the spray dryer. More preferably, the inlet temperature is in the range of 100 ℃ to 300 ℃. The silica particle concentration of the silica particle suspension is preferably 10 mass% or more and 30 mass% or less.

Examples of the supercritical fluid used for supercritical drying include carbon dioxide, water, methanol, ethanol, and acetone. The supercritical fluid is preferably supercritical carbon dioxide from the viewpoint of treatment efficiency and the viewpoint of suppressing generation of coarse particles. Specifically, the step of using supercritical carbon dioxide is performed, for example, by the following operations.

After the suspension is contained in the closed reactor and liquefied carbon dioxide is introduced, the inside of the closed reactor is pressurized by a high-pressure pump while heating the closed reactor, whereby the carbon dioxide in the closed reactor is brought into a supercritical state. Then, the liquefied carbon dioxide is flowed into the closed reactor, and the supercritical carbon dioxide is flowed out of the closed reactor, whereby the supercritical carbon dioxide is circulated into the suspension in the closed reactor. During the circulation of supercritical carbon dioxide to the suspension, the solvent is dissolved in the supercritical carbon dioxide, and the solvent is removed together with the supercritical carbon dioxide flowing out of the closed reactor. The temperature and pressure in the closed reactor are set to a temperature and pressure at which carbon dioxide becomes supercritical. Since the critical point of carbon dioxide is 31.1 ℃/7.38MPa, the temperature and pressure are set to, for example, 40 ℃ to 200 ℃ and below/10 MPa to 30 MPa. The flow rate of the supercritical fluid flowing to the closed reactor is preferably 80 mL/sec or more and 240 mL/sec or less.

The silica particles thus obtained are preferably decomposed and pulverized or sieved to remove coarse particles or aggregates. The decomposition and pulverization are performed by a dry pulverizing device such as a jet mill, a vibration mill, a ball mill, and a pin mill. The screening is performed by, for example, a vibrating screen, a pneumatic screen, or the like.

Toner for developing electrostatic charge image

The toner according to the present embodiment includes toner particles and silica particles externally added to the toner particles. The silica particles according to the present embodiment are used as silica particles.

[ toner particles ]

The toner particles are configured to contain, for example, a binder resin, and if necessary, a colorant, a release agent, and other additives.

Binding resin-

Examples of the binder resin include vinyl resins composed of homopolymers of monomers such as styrenes (e.g., styrene, p-chlorostyrene, α -methylstyrene, etc.), vinyl ketones (e.g., vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone, etc.), olefins (e.g., ethylene, propylene, butadiene, etc.), or copolymers obtained by combining two or more of these monomers, and such as styrene (e.g., styrene, p-chlorostyrene, α -methylstyrene, etc.), a (meth) acrylic ester (e.g., methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, etc.), an ethylenically unsaturated nitrile (e.g., acrylonitrile, methacrylonitrile, etc.), a vinyl ether (e.g., vinyl methyl ether, vinyl isobutyl ether, etc.), a vinyl ketone (e.g., vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone, etc.), an olefin (e.g., ethylene, propylene, butadiene, etc.).

Examples of the binder resin include non-vinyl resins such as epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, and modified rosins, mixtures thereof with the vinyl resins, and graft polymers obtained by polymerizing vinyl monomers under the coexistence of these resins.

These binder resins may be used singly or in combination of two or more.

As the binder resin, a polyester resin is preferable.

Examples of the polyester resin include known polyester resins.

Examples of the polyester resin include polycondensates of polycarboxylic acids and polyhydric alcohols. As the polyester resin, a commercially available product or a synthetic resin can be used.

Examples of the polycarboxylic acid include aliphatic dicarboxylic acids (for example, oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, alkenylsuccinic acid, adipic acid, sebacic acid, etc.), alicyclic dicarboxylic acids (for example, cyclohexanedicarboxylic acid, etc.), aromatic dicarboxylic acids (for example, terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, etc.), anhydrides thereof, and lower (for example, 1 to 5 carbon atoms) alkyl esters thereof. Among them, for example, aromatic dicarboxylic acids are preferable as the polycarboxylic acid.

As the polycarboxylic acid, a tri-or higher carboxylic acid having a crosslinked structure or a branched structure may be used in combination with the dicarboxylic acid. Examples of the tri-or higher carboxylic acid include trimellitic acid, pyromellitic acid, their anhydrides, and their lower (for example, 1 to 5 carbon atoms) alkyl esters.

The polycarboxylic acid may be used singly or in combination of two or more.

Examples of the polyhydric alcohol include aliphatic diols (e.g., ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butylene glycol, hexylene glycol, neopentyl glycol, etc.), alicyclic diols (e.g., cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol a, etc.), and aromatic diols (e.g., ethylene oxide adducts of bisphenol a, propylene oxide adducts of bisphenol a, etc.). Among them, the polyhydric alcohol is preferably an aromatic diol or an alicyclic diol, and more preferably an aromatic diol.

As the polyol, a three or more-membered polyol having a crosslinked structure or a branched structure may be used together with a diol. Examples of the three or more polyhydric alcohols include glycerol, trimethylolpropane and pentaerythritol.

The polyhydric alcohol may be used singly or in combination of two or more.

The glass transition temperature (Tg) of the polyester resin is preferably 50 ℃ or more and 80 ℃ or less, more preferably 50 ℃ or more and 65 ℃ or less.

The glass transition temperature is obtained from a Differential Scanning Calorimeter (DSC) curve, more specifically, from an "extrapolated glass transition onset temperature" described in the method for obtaining glass transition temperatures of JIS K7121-1987, "method for measuring transition temperatures of plastics".

The weight average molecular weight (Mw) of the polyester resin is preferably 5000 to 1000000, more preferably 7000 to 500000.

The number average molecular weight (Mn) of the polyester resin is preferably 2000 to 100000.

The molecular weight distribution Mw/Mn of the polyester resin is preferably 1.5 or more and 100 or less, more preferably 2 or more and 60 or less.

The weight average molecular weight and the number average molecular weight were measured by Gel Permeation Chromatography (GPC). As a measurement device, molecular weight measurement by GPC was performed using east Cao Zhi GPC HLC-8120GPC, east Cao Zhi column TSKgel SuperHM-M (15 cm), and THF solvent. The weight average molecular weight and the number average molecular weight were calculated using a molecular weight calibration curve prepared from a monodisperse polystyrene standard sample based on the measurement results.

The polyester resin is obtained by a known production method. Specifically, it is obtained, for example, by the following method: the polymerization temperature is set to 180 ℃ to 230 ℃ both inclusive, and the reaction system is depressurized as necessary to allow the reaction to proceed while removing water and alcohol generated during the condensation.

In the case where the monomers of the raw materials are insoluble or immiscible at the reaction temperature, a solvent having a high boiling point may be added as a cosolvent to dissolve them. At this time, the polycondensation reaction is performed while the cosolvent is distilled off. In the case where a monomer having poor compatibility is present, the monomer having poor compatibility and an acid or alcohol to be polycondensed with the monomer may be condensed in advance and then polycondensed with the main component.

The content of the binder resin is preferably 40% by mass or more and 95% by mass or less, more preferably 50% by mass or more and 90% by mass or less, and still more preferably 60% by mass or more and 85% by mass or less, relative to the entire toner particles.

Coloring agent-

Examples of the colorant include pigments such as carbon black, chrome yellow, hansa yellow, benzidine yellow, vat yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, fu Ergan orange, carmine, permanent red, brilliant carmine 3B, brilliant carmine 6B, dupont oil red, pyrazolone red, lithol red, rhodamine B lake, lake red C, pigment red, rose bengal, aniline blue, ultramarine blue, copper oil blue (calco oil blue), methylene chloride blue, phthalocyanine blue, pigment blue, phthalocyanine green, and malachite green oxalate; dyes such as acridine, xanthene, azo, benzoquinone, azine, anthraquinone, thioindigo, dioxazine, thiazine, azomethine, indigo, phthalocyanine, nigrosine, polymethine, triphenylmethane, diphenylmethane, and thiazole.

The colorant may be used alone or in combination of two or more.

The colorant may be used as required, or may be used in combination with a dispersant. In addition, a plurality of colorants may be used in combination.

The content of the colorant is preferably 1% by mass or more and 30% by mass or less, more preferably 3% by mass or more and 15% by mass or less, relative to the entire toner particle.

Mold release agent-

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

The melting temperature of the release agent is preferably 50 ℃ or more and 110 ℃ or less, more preferably 60 ℃ or more and 100 ℃ or less.

The melting temperature was obtained from a Differential Scanning Calorimeter (DSC) curve obtained from "melting peak temperature" described in the method for obtaining the melting temperature of "method for measuring the transition temperature of plastics" in JIS K7121-1987.

The content of the release agent is preferably 1% by mass or more and 20% by mass or less, more preferably 5% by mass or more and 15% by mass or less, relative to the entire toner particle.

Other additives-

Examples of the other additives include known additives such as magnetic materials, charge control agents, and inorganic powders. These additives are contained in the toner particles as internal additives.

Characteristics of toner particles and the like

The toner particles may be toner particles having a single-layer structure or toner particles having a so-called core/shell structure, which are composed of a core (core particle) and a coating layer (shell layer) coating the core.

The toner particles having a core-shell structure are preferably composed of, for example, a core portion configured to contain a binder resin, and if necessary, other additives such as a colorant and a release agent, and a coating layer configured to contain the binder resin.

The volume average particle diameter (D50 v) of the toner particles is preferably 2 μm or more and 10 μm or less, more preferably 4 μm or more and 8 μm or less.

The toner particles were measured for various average particle diameters and various particle size distribution indexes by using Coulter Multisizer II (Beckman Coulter, inc.), and ISOTON-II (Beckman Coulter, inc.) as an electrolyte.

In the measurement, a measurement sample of 0.5mg to 50mg was added to 2ml of a 5 mass% aqueous solution of a surfactant (preferably sodium alkylbenzenesulfonate) as a dispersant. It is added to the electrolyte solution in an amount of 100ml to 150 ml.

The electrolyte in which the sample was suspended was subjected to a dispersion treatment for 1 minute by an ultrasonic disperser, and the particle size distribution of particles having a particle diameter in the range of 2 μm to 60 μm was measured by Coulter Multisizer II using pores (aperture) having a pore diameter of 100 μm. The number of particles to be sampled is 50000.

The cumulative distribution of the volume and the number of the particles in the particle size range (channel) divided on the small diameter side is plotted based on the measured particle size distribution, and the particle size of the cumulative 16% is defined as the volume particle size D16v and the number average particle size D16p, the particle size of the cumulative 50% is defined as the volume average particle size D50v and the cumulative number average particle size D50p, and the particle size of the cumulative 84% is defined as the volume particle size D84v and the number average particle size D84p.

Using them, the method is defined by (D84 v/D16 v) ^1/2 Calculating the volume particle size distribution index (GSDv), by (D84 p/D16 p) ^1/2 A number average particle size distribution index (GSDp) was calculated.

The average circularity of the toner particles is preferably 0.94 or more and 1.00 or less, more preferably 0.95 or more and 0.98 or less.

The average circularity of the toner particles was obtained from (circle equivalent circumference)/(circumference) [ (circumference of circle having the same projection area as the particle image)/(circumference of particle projection image) ]. Specifically, the values were measured by the following methods.

First, toner particles to be measured are collected by suction to form a flat flow, a particle image is read as a still image by instantaneous strobe light emission, and an average circularity is determined by a flow type particle image analyzer (FPIA-3000 manufactured by hson america corporation (SYSMEX CORPORATION)) which performs image analysis on the particle image. The number of samples at the time of obtaining the average roundness is 3500.

When the toner has an external additive, the toner (developer) to be measured is dispersed in water containing a surfactant, and then subjected to ultrasonic treatment to obtain toner particles from which the external additive has been removed.

[ external additive ]

The toner according to the present embodiment contains the silica particles of the present embodiment as an external additive. The external addition amount of the silica particles in the present embodiment is preferably 0.1 part by mass or more and 3.0 parts by mass or less, more preferably 0.2 parts by mass or more and 2.0 parts by mass or less, and still more preferably 0.3 parts by mass or more and 1.5 parts by mass or less, with respect to 100 parts by mass of the toner particles.

The toner according to the present embodiment may contain silica particles other than the silica particles of the present embodiment as an external additive. The silica particles are preferably hydrophobic silica particles obtained by surface-treating silica particles such as sol-gel silica, hydrocolloid silica, alcoholic silica, fumed silica, and fused silica with a hydrophobizing agent (for example, a silane coupling agent, silicone oil, titanate coupling agent, aluminum coupling agent, and silazane compound).

When the toner according to the present embodiment contains silica particles other than the silica particles according to the present embodiment, the external addition amount of the silica particles is preferably 0.1 part by mass or more and 3.0 parts by mass or less, more preferably 0.2 parts by mass or more and 2.0 parts by mass or less, and still more preferably 0.3 parts by mass or more and 1.5 parts by mass or less, relative to 100 parts by mass of the toner particles.

The toner according to the present embodiment may contain an external additive other than the silica particles of the present embodiment. Examples of the external additive other than silica particles include 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 、K ₂ O·(TiO ₂ ) _n 、Al ₂ O ₃ ·2SiO ₂ 、CaCO ₃ 、MgCO ₃ 、BaSO ₄ 、MgSO ₄ 、SrTiO ₃ Inorganic particles; hydrophobic inorganic particles obtained by surface-treating these inorganic particles with a hydrophobizing agent (for example, a silane-based coupling agent, silicone oil, titanate-based coupling agent, aluminum-based coupling agent, silazane compound); resin particles such as polystyrene, polymethyl methacrylate, and melamine resin; a detergent active agent such as a higher fatty acid metal salt represented by zinc stearate and a fluorine-based high molecular weight body; etc.

[ method for producing toner ]

The toner according to the present embodiment can be obtained by externally adding an external additive to toner particles after the production of the toner particles.

The toner particles can be produced by any one of a dry process (for example, a kneading and pulverizing process) and a wet process (for example, an aggregation and coalescence process, a suspension polymerization process, a dissolution and suspension process, and the like). These methods are not particularly limited, and known methods can be used. Among them, toner particles are preferably obtained by an aggregation and coalescence method.

Specifically, for example, in the case of producing toner particles by the aggregation and coalescence method, toner particles are produced by the following steps: a step of preparing a resin particle dispersion in which resin particles as a binder resin are dispersed (a resin particle dispersion preparation step); a step (aggregated particle forming step) of forming aggregated particles by aggregating resin particles (other particles, if necessary) in a resin particle dispersion (in a dispersion obtained by mixing other particle dispersions, if necessary); and a step (fusion/coalescence step) of heating the aggregated particle dispersion liquid in which the aggregated particles are dispersed to fuse/coalesce the aggregated particles to form toner particles.

The details of each step will be described below.

In the following description, a method of obtaining toner particles including a colorant and a release agent is described, but the colorant and the release agent are used as needed. Of course, other additives besides colorants and mold release agents may be used.

Preparation of resin particle Dispersion

For example, a colorant particle dispersion in which colorant particles are dispersed and a release agent particle dispersion in which release agent particles are dispersed are prepared together with a resin particle dispersion in which resin particles to be a binder resin are dispersed.

The resin particle dispersion liquid is prepared, for example, by dispersing resin particles in a dispersion medium with a surfactant.

Examples of the dispersion medium used in the resin particle dispersion liquid include aqueous media.

Examples of the aqueous medium include distilled water, deionized water, and other water and alcohols. One kind of them may be used alone, or two or more kinds may be used in combination.

Examples of the surfactant include anionic surfactants such as sulfate salts, sulfonate salts, phosphate esters, and soaps; amine salt type and quaternary ammonium salt type cationic surfactants; nonionic surfactants such as polyethylene glycol-based, alkylphenol-ethylene oxide-based adducts and polyhydric alcohols-based surfactants. Among them, anionic surfactants and cationic surfactants are particularly mentioned. The nonionic surfactant may be used in combination with an anionic surfactant or a cationic surfactant.

The surfactant may be used alone or in combination of two or more.

As a method for dispersing the resin particles in the dispersion medium in the resin particle dispersion liquid, for example, a usual dispersion method such as a rotary shear type homogenizer, a ball MILL with a medium, a sand MILL, or Dai Nuomo (DYNO-MILL) is mentioned. Depending on the type of the resin particles, the resin particles may be dispersed in a dispersion medium by a phase inversion emulsification method. The phase inversion emulsification method is as follows: the resin to be dispersed is dissolved in a hydrophobic organic solvent in which the resin is soluble, and after the alkali is added to the organic continuous phase (O phase) and neutralized, an aqueous medium (W phase) is added to cause the phase transition from W/O to O/W, thereby dispersing the resin in the form of particles in the aqueous medium.

The volume average particle diameter of the resin particles dispersed in the resin particle dispersion is, for example, preferably 0.01 μm or more and 1 μm or less, more preferably 0.08 μm or more and 0.8 μm or less, and still more preferably 0.1 μm or more and 0.6 μm or less.

As the volume average particle diameter of the resin particles, a particle size distribution obtained by measurement by a laser diffraction particle size distribution measuring apparatus (for example, LA-700 manufactured by horiba ltd.) is used, and the cumulative distribution of the volume is plotted from the small particle diameter side for the divided particle size range (channel), and the particle diameter which is 50% of the total particle diameter is measured as the volume average particle diameter D50v. The volume average particle diameter of the particles in the other dispersion was measured in the same manner.

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

In the same manner as the resin particle dispersion, for example, a colorant particle dispersion, a release agent particle dispersion is also prepared. That is, the volume average particle diameter, the dispersion medium, the dispersion method, and the content of the particles in the resin particle dispersion are the same for the colorant particles dispersed in the colorant particle dispersion and the release agent particles dispersed in the release agent particle dispersion.

Agglomerated particle formation step

Next, the resin particle dispersion, the colorant particle dispersion, and the release agent particle dispersion are mixed.

Then, in the mixed dispersion, the resin particles, the colorant particles, and the release agent particles are heterogeneous and aggregated to form aggregated particles having a diameter close to the target toner particle diameter and containing the resin particles, the colorant particles, and the release agent particles.

Specifically, for example, an aggregating agent is added to the mixed dispersion, the pH of the mixed dispersion is adjusted to be acidic (for example, the pH is 2 or more and 5 or less), and after adding a dispersion stabilizer as needed, the mixed dispersion is heated to a temperature close to the glass transition temperature of the resin particles (specifically, for example, the glass transition temperature of the resin particles is-30 ℃ or more and the glass transition temperature is-10 ℃ or less), and the particles dispersed in the mixed dispersion are aggregated to form aggregated particles. In the agglomerated particle forming step, for example, the mixed dispersion may be stirred with a rotary shear homogenizer, and an agglomerating agent may be added at room temperature (for example, 25 ℃) to adjust the pH of the mixed dispersion to be acidic (for example, pH is 2 or more and 5 or less), and if necessary, a dispersion stabilizer may be added thereto, followed by heating.

Examples of the aggregating agent include surfactants having a polarity opposite to that of the surfactants contained in the mixed dispersion liquid, inorganic metal salts, and metal complexes having a valence of two or more. When the metal complex is used as the coagulant, the amount of the surfactant used is reduced, and the charging characteristics are improved.

Additives that form complexes or similar bonds with the metal ions of the agglutinating agent may be used together with the agglutinating agent as needed. As the additive, a chelating agent is preferably used.

Examples of the inorganic metal salt include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate; inorganic metal salt polymers such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide; etc.

As the chelating agent, a water-soluble chelating agent can be used. Examples of the chelating agent include hydroxycarboxylic acids such as tartaric acid, citric acid, and gluconic acid; aminocarboxylic acids such as iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), ethylenediamine tetraacetic acid (EDTA); etc.

The amount of the chelating agent to be added is preferably 0.01 to 5.0 parts by mass, more preferably 0.1 to 3.0 parts by mass, based on 100 parts by mass of the resin particles.

Fusion/coalescence procedure

Next, the aggregated particle dispersion liquid in which the aggregated particles are dispersed is heated, for example, to a temperature equal to or higher than the glass transition temperature of the resin particles (for example, a temperature 10 ℃ to 30 ℃ higher than the glass transition temperature of the resin particles), and the aggregated particles are fused/coalesced to form toner particles.

Toner particles were obtained through the above steps.

The toner particles may be produced by the following steps: after obtaining an aggregated particle dispersion in which aggregated particles are dispersed, the aggregated particle dispersion and the resin particle dispersion in which resin particles are dispersed are further mixed, and aggregated so that the resin particles further adhere to the surfaces of the aggregated particles to form second aggregated particles; and heating the second aggregated particle dispersion liquid in which the second aggregated particles are dispersed to fuse/coalesce the second aggregated particles to form toner particles of a core/shell structure.

After the completion of the fusion/coalescence step, the toner particles in the dispersion are subjected to a known cleaning step, solid-liquid separation step and drying step to obtain toner particles in a dried state. From the viewpoint of chargeability, the cleaning step is preferably to sufficiently perform replacement cleaning with deionized water. From the viewpoint of productivity, the solid-liquid separation step is preferably performed by suction filtration, pressure filtration, or the like. The drying step is preferably performed by freeze drying, air drying, fluidized drying, vibration type fluidized drying, or the like from the viewpoint of productivity.

The toner according to the present embodiment is produced by adding an external additive to the obtained dry toner particles and mixing the resultant toner particles. The mixing is preferably performed by, for example, a V-mixer, a henschel mixer, a rotkohler mixer, or the like. If necessary, coarse particles of the toner may be removed by using a vibration sieving machine, a wind sieving machine, or the like.

< Electrostatic Charge image developer >)

The electrostatic charge image developer according to the present embodiment includes at least the toner according to the present embodiment.

The electrostatic charge image developer according to the present embodiment may be a single-component developer containing only the toner according to the present embodiment, or may be a two-component developer obtained by mixing the toner with a carrier.

The carrier is not particularly limited, and known carriers can be used. Examples of the carrier include a coated carrier obtained by coating the surface of a core material composed of magnetic powder with a resin; a magnetic powder dispersion type carrier obtained by dispersing and preparing a magnetic powder in a matrix resin; a resin-impregnated carrier obtained by impregnating a porous magnetic powder with a resin; etc.

The magnetic powder dispersion type carrier and the resin impregnation type carrier may be a carrier obtained by coating the surface with a resin using constituent particles of the carrier as a core material.

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

Examples of the coating resin and the base resin include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, a vinyl chloride-vinyl acetate copolymer, a styrene-acrylate copolymer, a linear silicone resin containing an organosiloxane bond or a modified product thereof, a fluororesin, a polyester, a polycarbonate, a phenolic resin, and an epoxy resin. The coating resin and the matrix resin may contain other additives such as conductive particles. Examples of the conductive particles include particles of metals such as gold, silver, and copper, carbon black, titanium oxide, zinc oxide, tin oxide, barium sulfate, aluminum borate, and potassium titanate.

Examples of the method for coating the surface of the core material with the resin include a method in which the core material is coated with a coating layer-forming solution obtained by dissolving a coating resin and various additives (used as needed) in an appropriate solvent. The solvent is not particularly limited, and may be selected in consideration of the type of resin used, coating suitability, and the like.

Specific examples of the resin coating method include an impregnation method in which the core material is immersed in a coating layer forming solution; spraying a coating layer forming solution on the surface of the core material; a fluidized bed method in which a solution for forming a coating layer is sprayed in a state where a core material is floated by flowing air; a kneading coating method in which a core material of a carrier and a coating layer forming solution are mixed in a kneading coater and then the solvent is removed; etc.

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

Image Forming apparatus, image Forming method

An image forming apparatus and an image forming method according to the present embodiment will be described.

The image forming apparatus according to the present embodiment includes: an image holding body; a charging member that charges a surface of the image holding body; a static charge image forming member that forms a static charge image on a surface of the charged image holder; a developing member that accommodates an electrostatic charge image developer and develops an electrostatic charge image formed on a surface of the image holding body into a toner image by the electrostatic charge image developer; a transfer member that transfers the toner image formed on the surface of the image holding body onto the surface of the recording medium; and a fixing member that fixes the toner image transferred onto the surface of the recording medium. The electrostatic charge image developer according to the present embodiment is applied as an electrostatic charge image developer.

In the image forming apparatus according to the present embodiment, an image forming method (image forming method according to the present embodiment) including the steps of: a charging step of charging the surface of the image holder; a static charge image forming step of forming a static charge image on a surface of the charged image holder; a developing step of developing an electrostatic charge image formed on the surface of the image holder into a toner image with the electrostatic charge image developer according to the present embodiment; a transfer step of transferring the toner image formed on the surface of the image holder onto the surface of the recording medium; and a fixing step of fixing the toner image transferred onto the surface of the recording medium.

The image forming apparatus according to the present embodiment is applied to the following known image forming apparatus: a direct transfer system for directly transferring the toner image formed on the surface of the image holder onto a recording medium; an intermediate transfer system for primarily transferring the toner image formed on the surface of the image holding member onto the surface of the intermediate transfer member and secondarily transferring the toner image transferred onto the surface of the intermediate transfer member onto the surface of the recording medium; a device including a cleaning member for cleaning a surface of the image holder before charging after transferring the toner image; a device including a charge removing member for applying a charge removing light to the surface of the image holder before charging after transferring the toner image; etc.

In the case where the image forming apparatus according to the present embodiment is an intermediate transfer type apparatus, the transfer member is configured to have, for example, the following structure: an intermediate transfer body that transfers the toner image onto a surface; a primary transfer member that primary transfers the toner image formed on the surface of the image holding body onto the surface of the intermediate transfer body; and a secondary transfer member that secondarily transfers the toner image transferred onto the surface of the intermediate transfer body onto the surface of the recording medium.

In the image forming apparatus according to the present embodiment, for example, the portion including the developing member may be a cartridge structure (process cartridge) that is attached to and detached from the image forming apparatus. As the process cartridge, for example, a process cartridge having a developing member that accommodates the electrostatic charge image developer according to the present embodiment is preferably used.

Hereinafter, an example of the image forming apparatus according to the present embodiment is described, but the present invention is not limited thereto. In the following description, main portions shown in the drawings are described, and descriptions of other portions are omitted.

Fig. 1 is a schematic configuration diagram showing an image forming apparatus according to the present embodiment.

The image forming apparatus shown in fig. 1 includes first to fourth image forming units 10Y, 10M, 10C, 10K (image forming means) of an electrophotographic system that output images of respective colors of yellow (Y), magenta (M), cyan (C), and black (K) based on the color-separated image data. These image forming units (hereinafter, sometimes simply referred to as "units") 10Y, 10M, 10C, 10K are juxtaposed so as to be spaced apart from each other by a predetermined distance in the horizontal direction. These units 10Y, 10M, 10C, and 10K may be process cartridges that are attached to and detached from the image forming apparatus.

Above each unit 10Y, 10M, 10C, and 10K, an intermediate transfer belt (an example of an intermediate transfer body) 20 is provided so as to extend through each unit. The intermediate transfer belt 20 is provided to be wound around a driving roller 22 and a supporting roller 24, and travels in a direction from the first unit 10Y toward the fourth unit 10K. The backup roller 24 is biased in a direction away from the drive roller 22 by a spring or the like, not shown, to apply tension to the intermediate transfer belt 20 wound around both. An intermediate transfer body cleaning device 30 is provided on the image holding surface side of the intermediate transfer belt 20 so as to face the driving roller 22.

The toners of yellow, magenta, cyan, and black contained in the toner cartridges 8Y, 8M, 8C, and 8K are supplied to developing devices (an example of a developing member) 4Y, 4M, 4C, and 4K of the units 10Y, 10M, 10C, and 10K, respectively.

The first to fourth units 10Y, 10M, 10C, and 10K have the same structure and operation, and therefore, the first unit 10Y for forming a yellow image, which is disposed upstream in the traveling direction of the intermediate transfer belt, will be described as a representative.

The first unit 10Y has a photoconductor 1Y functioning as an image holder. Around the photoconductor 1Y, there are sequentially arranged: a charging roller (an example of a charging member) 2Y for charging the surface of the photoconductor 1Y with electricity of a predetermined potential; an exposure device (an example of a static charge image forming means) 3 for exposing the charged surface with a laser beam 3Y based on the color-separated image signal to form a static charge image; a developing device (an example of a developing member) 4Y that supplies charged toner to the electrostatic charge image to develop the electrostatic charge image; a primary transfer roller (an example of a primary transfer member) 5Y that transfers the developed toner image onto the intermediate transfer belt 20; and a photoconductor cleaning device (an example of a cleaning member) 6Y that removes toner remaining on the surface of the photoconductor 1Y after the primary transfer.

The primary transfer roller 5Y is disposed inside the intermediate transfer belt 20 and is disposed at a position facing the photoreceptor 1Y. Bias power supplies (not shown) for applying primary transfer biases are connected to the primary transfer rollers 5Y, 5M, 5C, and 5K of each unit. The bias power supplies change the value of the transfer bias applied to the primary transfer rollers under the control of a control unit, not shown.

Hereinafter, an operation of forming a yellow image in the first unit 10Y will be described.

First, before the operation, the surface of the photoconductor 1Y is charged to a potential of-600V to-800V by the charging roller 2Y.

The photoreceptor 1Y is formed by a conductive material (for example, a material having a volume resistivity of 1X 10 at 20 DEG C ^-6 Omega cm or less) is formed by laminating a photosensitive layer on a substrate. In general, the photosensitive layer has a high resistance (resistance of a general resin), but has a property that the resistivity of a portion to which a laser beam is irradiated changes when the laser beam is irradiated. Therefore, the laser beam 3Y is irradiated from the exposure device 3 onto the surface of the charged photoconductor 1Y based on the yellow image data transmitted from the control unit, not shown. Thereby, an electrostatic charge image of a yellow image pattern is formed on the surface of the photoconductor 1Y.

The electrostatic charge image is an image formed on the surface of the photoconductor 1Y by charging, and is a so-called negative latent image, which is formed as follows: the laser beam 3Y is used to reduce the resistivity of the irradiated portion of the photosensitive layer, thereby allowing the charged charges on the surface of the photosensitive body 1Y to flow, while the charges remain in the portion where the laser beam 3Y is not irradiated.

The electrostatic charge image formed on the photoconductor 1Y rotates to a preset development position as the photoconductor 1Y advances. Then, at this development position, the electrostatic charge image on the photoconductor 1Y is developed into a toner image by the developing device 4Y, and visualized.

In the developing device 4Y, for example, an electrostatic charge image developer containing at least yellow toner and a carrier is accommodated. The yellow toner is triboelectrically charged by stirring in the developing device 4Y, and is held by a developer roller (an example of a developer holder) with a charge of the same polarity (negative polarity) as that of the charge of the photoconductor 1Y. By passing the surface of the photoconductor 1Y through the developing device 4Y, the yellow toner is electrostatically attached to the charge-removed latent image portion on the surface of the photoconductor 1Y, and the latent image is developed with the yellow toner. The photoreceptor 1Y on which the yellow toner image is formed continues to travel at a predetermined speed, so that the toner image developed on the photoreceptor 1Y is conveyed to a predetermined primary transfer position.

When the yellow toner image on the photoconductor 1Y is transferred to the primary transfer position, a primary transfer bias is applied to the primary transfer roller 5Y, and electrostatic force from the photoconductor 1Y toward the primary transfer roller 5Y acts on the toner image, thereby transferring the toner image on the photoconductor 1Y to the intermediate transfer belt 20. The transfer bias applied at this time is (+) in polarity opposite to the polarity (-) of the toner, and is controlled to +10μa in the first unit 10Y by a control unit (not shown), for example.

The toner remaining on the photoconductor 1Y is removed and collected by the photoconductor cleaning device 6Y.

The primary transfer bias applied to the primary transfer rollers 5M, 5C, 5K after the second unit 10M is also controlled with reference to the first unit.

In this way, the intermediate transfer belt 20 after the transfer of the yellow toner image by the first unit 10Y is sequentially conveyed so as to pass through the second to fourth units 10M, 10C, 10K, and is transferred a plurality of times so as to superimpose the toner images of the respective colors.

The intermediate transfer belt 20 after the four color toner images are transferred a plurality of times through the first to fourth units reaches a secondary transfer portion composed of the intermediate transfer belt 20, a backup roller 24 in contact with the inner surface of the intermediate transfer belt, and a secondary transfer roller (an example of a secondary transfer member) 26 arranged on the image holding surface side of the intermediate transfer belt 20. On the other hand, a recording sheet (an example of a recording medium) P is fed to a gap where the secondary transfer roller 26 contacts the intermediate transfer belt 20 via a feeding mechanism at a predetermined timing, and a secondary transfer bias is applied to the backup roller 24. The transfer bias applied at this time is of the same polarity (-) as the polarity (-) of the toner, and an electrostatic force from the intermediate transfer belt 20 toward the recording paper P acts on the toner image, thereby transferring the toner image on the intermediate transfer belt 20 onto the recording paper P. The secondary transfer bias at this time is determined based on the resistance detected by a resistance detecting member (not shown) that detects the resistance of the secondary transfer portion, and is voltage-controlled.

Then, the recording paper P is conveyed to a nip portion (nip portion) of a pair of fixing rollers in a fixing device (an example of a fixing member) 28, and the toner image is fixed to the recording paper P, thereby forming a fixed image.

The recording paper P on which the toner image is transferred includes, for example, plain paper used in electrophotographic copying machines, printers, and the like. The recording medium includes, in addition to the recording paper P, an OHP sheet and the like.

In order to further improve the smoothness of the image surface after fixing, the surface of the recording paper P is preferably also smooth, and for example, coated paper obtained by coating the surface of plain paper with a resin or the like, coated paper for printing, or the like is preferably used.

The recording paper P after fixing the color image is conveyed toward the discharge portion, and a series of color image forming operations is terminated.

< Process Cartridge, toner Cartridge >)

A process cartridge according to the present embodiment will be described.

The process cartridge according to the present embodiment includes a developing member that accommodates the electrostatic charge image developer according to the present embodiment and develops an electrostatic charge image formed on a surface of an image holding member into a toner image with the electrostatic charge image developer, and is attached to and detached from an image forming apparatus.

The process cartridge according to the present embodiment is not limited to the above-described configuration, and may be configured to include a developing member and, if necessary, at least one member selected from the group consisting of an image holder, a charging member, an electrostatic charge image forming member, and a transfer member.

Hereinafter, an example of the process cartridge according to the present embodiment is described, but the present invention is not limited thereto. In the following description, main portions shown in the drawings are described, and descriptions of other portions are omitted.

Fig. 2 is a schematic configuration diagram showing a process cartridge according to the present embodiment.

The process cartridge 200 shown in fig. 2 is configured to be a cartridge in which, for example, a photoconductor 107 (an example of an image holder), a charging roller 108 (an example of a charging member) provided around the photoconductor 107, a developing device 111 (an example of a developing member), and a photoconductor cleaning device 113 (an example of a cleaning member) are integrally held by a frame 117 provided with a mounting rail 116 and an opening 118 for exposure.

In fig. 2, 109 denotes an exposure device (an example of an electrostatic charge image forming member), 112 denotes a transfer device (an example of a transfer member), 115 denotes a fixing device (an example of a fixing member), and 300 denotes a recording sheet (an example of a recording medium).

Next, a toner cartridge according to the present embodiment will be described.

The toner cartridge according to the present embodiment is a toner cartridge that accommodates the toner according to the present embodiment and is attached to and detached from an image forming apparatus. The toner cartridge accommodates a replenishment toner for supplying to a developing member provided in the image forming apparatus.

The image forming apparatus shown in fig. 1 is an image forming apparatus having a structure in which toner cartridges 8Y, 8M, 8C, and 8K are attached and detached, and developing devices 4Y, 4M, 4C, and 4K are connected to toner cartridges corresponding to respective developing devices (colors) via toner supply pipes not shown. When the toner contained in the toner cartridge is reduced, the toner cartridge is replaced.

Examples

Embodiments of the present invention will be described in detail below with reference to examples, but the embodiments of the present invention are not limited to these examples.

In the following description, unless otherwise specified, "parts" and "%" are based on mass.

Unless otherwise specified, synthesis, processing, manufacture, etc. are performed at room temperature (25 ℃.+ -. 3 ℃).

Example 1 to example 29, comparative example 1 to comparative example 2, reference example 1 to reference example 2 >, and a method of producing a semiconductor device

Granulation process-

Methanol (MeOH), deionized water and aqueous ammonia (NH) were charged into a glass reaction vessel equipped with a metal stirring rod, a dropping nozzle and a thermometer under the conditions shown in Table 1 ₄ OH water) and stirred and mixed to obtain a base catalyst solution.

Then, the temperature of the base catalyst solution was adjusted to 40 ℃, and the base catalyst solution was subjected to nitrogen substitution. Next, tetramethoxysilane (TMOS) and ammonia water (NH) were simultaneously added dropwise while stirring the base catalyst solution according to the conditions shown in Table 1 ₄ OH water) to obtain a silica masterbatch suspension.

The water concentration of the silica master batch suspension after granulation (i.e., the point at which the supply of the tetraalkoxysilane and the base catalyst is completed) is indicated (in the table, simply referred to as "post-granulation, water concentration").

Coating procedure-

While heating the silica master batch suspension to 40 ℃ and stirring, a silane coupling agent of the type shown in table 1 was added to the suspension. After that, stirring was continued for 120 minutes to allow the silane coupling agent to react. Thereby, a clad structure is formed.

The silane coupling agent was added in the parts shown in table 1 to 100 parts by mass of the solid content of the silica master batch suspension.

Attachment procedure

An alcohol solution obtained by diluting a nitrogen element compound (in the table, expressed as an N compound) of the type shown in table 1 with butanol was produced.

Next, an alcohol solution obtained by diluting the nitrogen element-containing compound with butanol is added to the suspension. At this time, the addition of the alcohol solution was performed so that the amount of the nitrogen-containing element compound was set to the amount shown in table 1 with respect to 100 parts by mass of the solid content of the silica master batch suspension. Then, the mixture was stirred at 30℃for 100 minutes, thereby obtaining a suspension containing a nitrogen element compound.

Drying procedure-

Next, the suspension was contained in a reaction tank, and CO was added while stirring ₂ The temperature and pressure in the reaction tank are raised to 150 ℃ and 15Mpa. CO is stirred while maintaining the temperature and pressure ₂ Inflow and outflow were performed at a flow rate of 5L/min. Thereafter, the solvent was removed over 120 minutes, thereby obtaining silica particles of each example.

< measurement of Properties of silica particles >

The following properties of the silica particles obtained were measured by the measurement method described above.

Pore volume C (expressed as "pore volume C before calcination at 350 ℃ in the table) having a pore diameter of 2nm or less, which is determined from the pore distribution curve before calcination at 350 ℃ in the nitrogen adsorption method.

Pore volume D (expressed as "pore volume D after calcination at 350 ℃ in the Table" from the pore distribution curve after calcination at 350 ℃ in the nitrogen adsorption method) having a pore diameter of 2nm or less

Pore volume A (expressed as "pore volume A before calcination at 350 ℃ in the table) having a pore diameter of 2nm to 25nm based on the pore distribution curve after calcination at 350 ℃ in the nitrogen adsorption method.

Pore volume B having a pore diameter of 2nm to 25nm (expressed as "pore volume B after calcination at 350 ℃ in the table)" obtained from the pore distribution curve after calcination at 350 ℃ in the nitrogen adsorption method

Nitrogen content relative to silica particles (expressed in the table as N compound amount)

Number average particle diameter (in the table, expressed as "particle diameter")

The silica particles of examples and reference examples each had at least one peak in the pore distribution curve after calcination at 350℃in the nitrogen adsorption method, in the range of pore diameters of 2nm or less and in the range of more than 2nm and 50nm or less.

< evaluation of charged ascending property >)

The silica particles of each example were mixed with resin particles (for example, crosslinked acrylic resin particles, manufactured by japan catalyst system, MA 1010), and a mixture in which silica particles were attached to the surface of the resin particles at a coating ratio of 25% was obtained. Then, 15g of the mixture 10 parts by mass and ferrite powder (for example,

100 parts by mass of KNI106GSM manufactured by JFE chemical Co., ltd.) and left for one day under high temperature and high humidity conditions (temperature 27 ℃ C. And relative humidity 85%).

Next, the mixture and ferrite powder added to the flask were stirred using a rocking mixer (e.g., manufactured by Shinmaru Enterprises Corporation, T2F) at a mixing speed of 49 rpm.

Samples were obtained with stirring for 5 seconds, 10 seconds, 30 seconds, 60 seconds, 120 seconds, and 300 seconds, and the charge values of the samples were measured. For measurement of the charge value, the stirred mixture was charged into a metal container covered with a 20 μm mesh stainless steel wire net, and was measured using a blow-out charge amount measuring device (toshiba Chemical Corporation, TB-200).

Then, the time for which the charge value was saturated was set as the time required for the charge to rise, and evaluation was performed. For example, when the change in charge amount between a sample stirred for 5 seconds and a sample stirred for 10 seconds is within a range of ±2 μc/g, the time required for the charge to rise was evaluated as 5 seconds.

In addition, the abbreviations in table 1 are as follows in detail.

MTMS: methyltrimethoxysilane

·TP-415：[N ⁺ (CH) ₃ (C ₁₄ C ₂₉ ) ₂ ] ₄ Mo ₈ O ₂₈ ^4- (N, N-Dimethyl-N-tetradecyl-1-tetradecanaminium, hexa- μ -oxoetra- μ 3-oxoodi- μ 5-oxoetradecaoxoamoxybdate (4-) (4:1) (extraction amount x=61 to 89 mass% based on an ammonia/methanol mixed solution, ratio X/y=0.03 to 0.26) based on an extraction amount Y of water)

P-51: benzyl trimethyl ammonium chloride

TMBAC: benzyl tributyl ammonium chloride

[ Table 1-1]

[ tables 1-2]

From the above results, it can be seen that: the charging ascending property of this example was superior to that of the comparative example.

Reference example 1 is a silica particle corresponding to the present embodiment, but contains no nitrogen element compound.

Reference example 2 shows an example in which D/B is silica particles corresponding to the present embodiment, but contains a nitrogen element-containing compound excessively.

(additionally remembered)

(((1)))

A silica particle having at least one peak in a pore size of 2nm or less and in a range exceeding 2nm and 50nm or less in a pore distribution curve after calcination at 350 ℃ by a nitrogen adsorption method,

when D and B are used as pore volumes in a range of 2nm or less and a range of 2nm or more and 25nm or less, D/B is 0.50 or more and 2.50 or less, respectively, as determined from a pore distribution curve obtained by a nitrogen adsorption method after calcination at 350 ℃.

(((2)))

The silica particles according to (((1))), wherein the D/B is 0.55 or more and 2.00 or less.

(((3)))

The silica particles according to (((1))) or (((2))), wherein the D is 0.10cm ³ Above/g and 1.10cm ³ And/g or less.

(((4)))

The silica particles according to any one of (((1))) to ((3)), wherein a nitrogen-containing element compound is contained.

(((5)))

The silica particles according to (((4))), wherein the content of the nitrogen-containing element compound is 0.02 mass% or more and 1.20 mass% or less with respect to the nitrogen content of the silica particles.

(((6)))

The silica particles according to either (4) or (5), wherein when the pore volume of the silica particles having a pore diameter of 2nm or less obtained from the pore distribution curve before calcination at 350 ℃ by the nitrogen adsorption method is C, the ratio C/D of C to D is 0.05 or more and 0.82 or less.

(((7)))

The silica particles according to (((6))), wherein the C/D is 0.05 or more and 0.70 or less.

(((8)))

The silica particles according to any one of (4) to (7), wherein when the pore volume of the silica particles obtained from the pore distribution curve before calcination at 350 ℃ by the nitrogen adsorption method is a, the ratio a/B of a to B is 0 to 0.92 inclusive, the pore volume is 2nm to 25nm inclusive.

(((9)))

The silica particles according to any one of (((4))) to (((8)), wherein the number average particle diameter is 40nm or more and 200nm or less.

(((10)))

The silica particles according to any one of (4) to (9), wherein the nitrogen-containing element compound is at least one selected from the group consisting of quaternary ammonium salts, primary amine compounds, secondary amine compounds, tertiary amine compounds, amide compounds, imine compounds, and nitrile compounds.

(((11)))

An electrostatic charge image developing toner comprising:

toner particles; and

The silica particles of any one of (4) to (10), which are externally added to the toner particles.

(((12)))

An electrostatic charge image developer comprising (((11))) the toner for electrostatic charge image development.

(((13)))

A toner cartridge containing (((11))) the toner for electrostatic charge image development,

the toner cartridge is attached to and detached from the image forming apparatus.

(((14)))

A process cartridge is provided with a developing member which accommodates (((12))) the electrostatic charge image developer and develops an electrostatic charge image formed on a surface of an image holding body into a toner image by the electrostatic charge image developer,

the process cartridge is attached to and detached from the image forming apparatus.

(((15)))

An image forming apparatus includes:

an image holding body;

a charging member that charges a surface of the image holding body;

a static charge image forming member that forms a static charge image on a surface of the charged image holding body;

a developing member that accommodates (((12))) the electrostatic charge image developer and develops an electrostatic charge image formed on a surface of the image-holding body into a toner image by the electrostatic charge image developer;

A transfer member that transfers the toner image formed on the surface of the image holder onto the surface of a recording medium; and

and a fixing member that fixes the toner image transferred onto the surface of the recording medium.

(((16)))

An image forming method, comprising:

a charging step of charging the surface of the image holder;

a static charge image forming step of forming a static charge image on the surface of the charged image holder;

a developing step of developing an electrostatic charge image formed on a surface of the image holder into a toner image by the electrostatic charge image developer;

a transfer step of transferring the toner image formed on the surface of the image holder onto the surface of a recording medium; and

and a fixing step of fixing the toner image transferred onto the surface of the recording medium.

According to (((1))), a silica particle capable of improving charge rising property as compared with the case of: that is, the silica particles have at least one peak in the pore distribution curve after calcination at 350 ℃ in the nitrogen adsorption method in the range of pore diameters of 2nm or less and in the range of more than 2nm and 50nm or less, and the D/B is less than 0.50 when D and B are the pore volumes in the range of pore diameters of 2nm or less and in the range of 2nm to 25nm, respectively, obtained from the pore distribution curve after calcination at 350 ℃ in the nitrogen adsorption method.

According to (((2))), a silica particle capable of improving the charge rising property as compared with the case where D/B is less than 0.55 can be provided.

According to (((3))), a silica particle can be provided, which is compared withD is less than 0.10cm ³ In the case of/g, the charge rising property can be improved.

According to (((4))), a silica particle excellent in charge rising property can be provided as compared with the case where the nitrogen-containing element compound is not contained.

According to (((5))), it is possible to provide silica particles excellent in charge rising property as compared with the case where the content of the nitrogen-containing element compound is less than 0.02 mass% relative to the nitrogen content of the silica particles.

According to the aspect (((6))), there can be provided silica particles excellent in charge rising property as compared with the case where the ratio C/D of C to D exceeds 0.82 when the pore volume of the silica particles having a pore diameter of 2nm or less obtained from the pore distribution curve before calcination at 350 ℃ by the nitrogen adsorption method is C, which contains a nitrogen element compound.

According to (((7))), a silica particle excellent in charge rising property can be provided as compared with the case where C/D exceeds 0.70.

According to the aspect (((8))), there can be provided silica particles excellent in charge rising property as compared with the case where the ratio A/B of A to B is more than 0.92 when the pore volume of the silica particles is A, the pore volume being 2nm or more and 25nm or less, the pore volume being obtained by the pore distribution curve before calcination at 350 ℃ by the nitrogen adsorption method, and containing a nitrogen element compound.

According to (((9))), a silica particle can be provided which is excellent in charge rising property even when the number average particle diameter is 40nm or more and 200nm or less, compared with the following case: specifically, the silica particles contain a nitrogen element compound, and have at least one peak in the pore distribution curve after calcination at 350 ℃ in the nitrogen adsorption method, in the pore diameter range of 2nm or less and in the range of more than 2nm and 50nm or less, respectively, and when the pore volume in the range of 2nm or less and in the range of 2nm to 25nm or more and B is D and B, respectively, as determined from the pore distribution curve after calcination at 350 ℃ in the nitrogen adsorption method, D/B is less than 0.50.

According to (((10))), there can be provided a silica particle which contains at least one selected from the group consisting of a quaternary ammonium salt, a primary amine compound, a secondary amine compound, a tertiary amine compound, an amide compound, an imine compound, and a nitrile compound, and is excellent in charge rising property as compared with the following case: specifically, the silica particles contain a nitrogen element compound, and have at least one peak in the pore distribution curve after calcination at 350 ℃ in the nitrogen adsorption method, in the pore diameter range of 2nm or less and in the range of more than 2nm and 50nm or less, respectively, and when the pore volume in the range of 2nm or less and in the range of 2nm to 25nm or more and B is D and B, respectively, as determined from the pore distribution curve after calcination at 350 ℃ in the nitrogen adsorption method, D/B is less than 0.50.

According to (((11))), (((12))), (((13))), (((14))), (((15))) and (((16))), there can be provided a toner for developing an electrostatic charge image and an electrostatic charge image developer, a toner cartridge, a process cartridge, an image forming apparatus and an image forming method using the toner for developing an electrostatic charge image, which are excellent in charging rising property as compared with the case where the following silica particles are applied as an external additive to the toner for developing an electrostatic charge image: specifically, the silica particles contain a nitrogen element compound, and have at least one peak in the pore distribution curve after calcination at 350 ℃ in the nitrogen adsorption method, wherein D/B is less than 0.50 when D and B are respectively the pore diameters in the range of 2nm or less and the pore volumes in the range of 2nm to 25nm inclusive, which are obtained from the pore distribution curve after calcination at 350 ℃ in the nitrogen adsorption method.

Claims (16)

1. A silica particle, characterized in that,

at least one peak is present in the pore distribution curve after calcination at 350 ℃ in the nitrogen adsorption method in a range where the pore diameter is 2nm or less and in a range exceeding 2nm and 50nm or less,

when D and B are used as pore volumes in a range of 2nm or less and a range of 2nm or more and 25nm or less, D/B is 0.50 or more and 2.50 or less, respectively, as determined from a pore distribution curve obtained by a nitrogen adsorption method after calcination at 350 ℃.

2. The silica particles according to claim 1, wherein,

the D/B is 0.55-2.00.

3. Silica particles according to claim 1 or 2, wherein,

the D is 0.10cm ³ Above/g and 1.10cm ³ And/g or less.

4. A silica particle according to claim 1 to 3, wherein,

comprising a nitrogen element-containing compound.

5. The silica particles according to claim 4, wherein,

the nitrogen-containing element compound is contained in an amount of 0.02 mass% to 1.20 mass% inclusive relative to the nitrogen content of the silica particles.

6. Silica particles according to claim 4 or 5, wherein,

when the pore volume, which is determined from the pore distribution curve of nitrogen adsorption at 350 ℃ before calcination and has a pore diameter of 2nm or less, is C, the ratio C/D of C to D is 0.05 to 0.82.

7. The silica particles according to claim 6, wherein,

the C/D is 0.05 to 0.70.

8. Silica particles according to any one of claims 4 to 7, wherein,

when the pore volume of a pore diameter of 2nm to 25nm, which is obtained from the pore distribution curve of nitrogen adsorption method before calcination at 350 ℃, is A, the ratio A/B of A to B is 0 to 0.92.

9. Silica particles according to any one of claims 4 to 8, wherein,

the number average particle diameter is 40nm to 200 nm.

10. Silica particles according to any one of claims 4 to 9, wherein,

the nitrogen-containing element compound is at least one selected from the group consisting of quaternary ammonium salts, primary amine compounds, secondary amine compounds, tertiary amine compounds, amide compounds, imine compounds, and nitrile compounds.

11. An electrostatic charge image developing toner comprising:

toner particles; and

the silica particles of any one of claims 4 to 10, which are externally added to the toner particles.

12. An electrostatic charge image developer comprising the toner for electrostatic charge image development according to claim 11.

13. A toner cartridge containing the toner for developing an electrostatic charge image according to claim 11,

the toner cartridge is attached to and detached from the image forming apparatus.

14. A process cartridge comprising a developing member which accommodates the electrostatic charge image developer according to claim 12 and develops an electrostatic charge image formed on a surface of an image holding body into a toner image by the electrostatic charge image developer,

The process cartridge is attached to and detached from the image forming apparatus.

15. An image forming apparatus, comprising:

an image holding body;

a charging member that charges a surface of the image holding body;

a static charge image forming member that forms a static charge image on a surface of the charged image holding body;

a developing member that accommodates the electrostatic charge image developer of claim 12 and develops an electrostatic charge image formed on a surface of the image-holding body into a toner image by the electrostatic charge image developer;

a transfer member that transfers the toner image formed on the surface of the image holder onto the surface of a recording medium; and

and a fixing member that fixes the toner image transferred onto the surface of the recording medium.

16. An image forming method, comprising:

a charging step of charging the surface of the image holder;

a static charge image forming step of forming a static charge image on the surface of the charged image holder;

a developing step of developing an electrostatic charge image formed on a surface of the image holder into a toner image with the electrostatic charge image developer according to claim 12;

A transfer step of transferring the toner image formed on the surface of the image holder onto the surface of a recording medium; and

and a fixing step of fixing the toner image transferred onto the surface of the recording medium.