JP2018180279A - Toner for electrostatic charge image development - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner for electrostatic charge image development that can form high-quality images for a long period in any one of a high-temperature and high-humidity environment and a low-temperature and low-humidity environment.SOLUTION: A toner for electrostatic charge image development of the present invention is a toner for electrostatic charge image development that includes a toner base particle having an external additive on its surface, and contains at least silica particles as the external additive. The silica particles contain a sulfur element.SELECTED DRAWING: None

Description

  The present invention relates to a toner for electrostatic charge image development. More particularly, the present invention relates to a toner for developing an electrostatic charge image capable of forming a high quality image for a long time in any of a high temperature, high humidity, low temperature and low humidity environment.

  The performance required for the electrostatic charge image developing toner (hereinafter, also simply referred to as "toner") used for image formation of the electrophotographic system includes charging performance, fluidity, transferability, cleaning property and the like. Conventionally, particles made of various organic compounds and inorganic compounds called external additives are added to toners for the purpose of imparting and improving these characteristics. As a typical external additive, inorganic particles such as silica and titanium oxide are known. Among them, silica is highly essential for obtaining a high quality image with high negative chargeability.

  In recent years, the demand for high definition and high quality images has been increasing, and toner with a small particle size has become mainstream. These small particle size toners have high adhesion to the surface of the photoreceptor and tend to remain as transfer residual toner. Transfer residual toner is usually removed by a cleaning process, but since external additives (mainly silica particles) present on the toner surface or detached from the toner surface have high hardness, they are exposed to the cleaning blade or roller and photosensitive When staying in the gap between the bodies, there is a problem that the surface of the photosensitive member is excessively worn away or damaged, which causes an image defect and the like.

In Patent Document 1, unevenness in the amount of external additive adhering to the surface of the cleaning roller is obtained by dividing the toner conveyance path into a plurality of parts in the longitudinal direction and shortening the length per conveyance path. By suppressing, the wear nonuniformity of the longitudinal direction of an electrophotographic photosensitive member surface is suppressed, and the technique which suppresses the density nonuniformity of an output image is disclosed.
However, even if the unevenness of the amount of the external additive deposited and adhered to the cleaning member is suppressed, when the external additive having high hardness (mainly, silica particles) is contained, excessive wear of the photoreceptor surface is caused. There is a problem that the image unevenness can not be suppressed and it is difficult to form a high quality image for a long time.

JP, 2014-219484, A

  The present invention has been made in view of the above problems and circumstances, and the problem to be solved is to provide a toner for developing an electrostatic charge image capable of forming a high quality image for a long time in any of high temperature and high humidity and low temperature and low humidity environment. It is to be.

The present inventors contain at least silica particles as an external additive in the toner in the process of examining the cause of the above problems and the like in order to solve the above problems, and the silica particles contain sulfur element. Thus, the inventors have found that high-quality images can be formed for a long time in any of high-temperature, high-humidity and low-temperature, low-humidity environments, resulting in the present invention.
That is, the subject concerning the present invention is solved by the following means.

1. A toner for developing an electrostatic charge image comprising toner base particles having an external additive on the surface, comprising:
At least silica particles are contained as the external additive,
The toner for developing an electrostatic charge image, wherein the silica particles contain a sulfur element.

  2. The toner for electrostatic image development according to claim 1, wherein among the silica particles, a silica host particle contains a sulfur element.

  3. The toner according to claim 1 or 2, wherein the content of sulfur element contained in the silica particles is in the range of 20 to 50000 mass ppm.

  4. The toner for electrostatic image development according to any one of Items 1 to 3, wherein the silica particles contain a sodium element.

5. As the external additive, in addition to the silica particles, the second silica particles are contained,
The toner for electrostatic image development according to any one of Claims 1 to 4, wherein the second silica particles are surface-modified with silicone oil.

6. The toner base particles contain a binder resin,
The styrene-acrylic resin contained in the binder resin is in the range of 50 to 100% by mass with respect to the total amount of the binder resin. The toner for developing an electrostatic charge image according to one aspect.

According to the above means of the present invention, it is possible to provide a toner for developing an electrostatic charge image capable of forming a high quality image for a long time in any of a high temperature, high humidity, low temperature and low humidity environment.
The mechanism or mechanism of action of the effects of the present invention is not clear but is presumed as follows.

The toner of the present invention uses silica particles containing sulfur as an external additive.
Usually, the silica particles used for the external additive are amorphous silicon dioxide, and SiO ₄ tetrahedra are solidified with irregular arrangement. Here, amorphous silicon dioxide forms a three-dimensional network and forms hard particles.
The silica particles according to the present invention are considered to have been able to divide the three-dimensional network of silicon dioxide and reduce the hardness by containing sulfur element. The sulfur element is an element of the third period having a relatively large atomic radius among non-metallic elements such as carbon element, nitrogen element and phosphorus element, and can effectively divide a three-dimensional network it is conceivable that. Further, the method of using sulfur element is also useful from the viewpoint of safety and manufacturability.
In addition, when a toner containing such silica particles as an external additive is used, it is possible to suppress excessive wear on the surface of the photosensitive member or scratching the surface, so that development stability and abrasion of the photosensitive member can be prevented. It is thought that the suppression was able to be compatible. Then, it is considered that high-quality image formation can be performed for a long time in any of high temperature and high humidity and low temperature and low humidity environment.

Schematic diagram for illustrating the configuration of the resistance measuring device

  The toner for electrostatic charge image development of the present invention is a toner for electrostatic charge image development containing toner base particles having an external additive on the surface, wherein the toner contains at least silica particles as the external additive, and the silica particles Is characterized in that it contains elemental sulfur. This feature is a technical feature common to the inventions of the respective claims.

  In the embodiment of the present invention, from the viewpoint of effectively obtaining the effects of the present invention, it is preferable that the silica base particles contain sulfur element among the above-mentioned silica particles. Thereby, it is considered that the effect of dividing the three-dimensional network of silicon dioxide described above to lower the hardness of the silica particles can be effectively obtained.

  Moreover, as an embodiment of this invention, it is preferable that content of the sulfur element contained in the said silica parent particle exists in the range of 20-50000 mass ppm. By setting the content to 20 mass ppm or more, it is considered that the effect of dividing the three-dimensional network of silicon dioxide described above is effectively obtained and the effect of lowering the hardness of the silica particles is obtained. The deterioration of unevenness can be suppressed. Further, by setting the amount to 50000 mass ppm or less, the effect of the three-dimensional network division of silicon dioxide described above is not excessively increased, and the hardness of the silica particles is prevented from being excessively lowered, and the photoreceptor wear is appropriately reduced. By doing this, it is possible to suppress image contamination due to photoreceptor filming.

  In the embodiment of the present invention, the silica particles preferably contain a sodium element. When the silica particles contain a sodium element, toner scattering, toner spilling, and the like do not occur even when printing is performed with high coverage, and an effect that high quality images can be obtained is obtained. The reason is not clear, but it is presumed that the rising of the charge is improved by the decrease in the resistance of the particles as compared with the one in which the sodium element is not contained.

  Moreover, as an embodiment of the present invention, in addition to the silica particles, the second silica particles are contained as the external additive, and the second silica particles are surface-modified with silicone oil. preferable. As a result, the silicone oil released from the second silica particles is transferred to the photosensitive member, and the friction between the silica particles and the photosensitive member is reduced, so that the synergistic effect of suppressing the photosensitive member wear can be obtained.

  Further, in an embodiment of the present invention, the toner base particles contain a binder resin, and the styrene-acrylic resin contained in the binder resin is 50 to 100 based on the total amount of the binder resin. It is preferable to be in the range of mass%. The toner base particles containing a styrene-acrylic resin as the main component have high adhesion to the silica particles used as the external additive, and therefore, the surface of the photosensitive member formed of the liberated silica particles is suppressed by suppressing the number of liberated silica particles. Excessive wear and tear can be suppressed.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention, its components, and modes for carrying out the present invention will be described in detail below.
In the present application, “to” is used in the meaning including the numerical values described before and after that as the lower limit value and the upper limit value.

[Overview of Toner for Developing Electrostatic Charge Image]
The toner for electrostatic charge image development of the present invention is a toner for electrostatic charge image development containing toner base particles having an external additive on the surface, wherein the toner contains at least silica particles as the external additive, and the silica particles Is characterized in that it contains elemental sulfur.
Further, in the present invention, "toner for developing electrostatic charge image" refers to an aggregate of "toner particles". Further, toner particles refer to toner base particles to which an external additive is added. In the present invention, when it is not necessary to distinguish between toner base particles and toner particles, they may be simply referred to as toner particles.

<Toner base particle>
The toner base particles according to the present invention preferably contain an amorphous resin and a crystalline resin as a binder resin. The toner base particles may further contain other components such as a colorant, a release agent (wax), a charge control agent, and the like, as necessary.
In the present invention, the toner base particles to which an external additive is added are referred to as toner particles.

<External additive>
The toner of the present invention contains at least silica particles (hereinafter also referred to as “first silica particles”) as an external additive, and the first silica particles contain a sulfur element. In addition, the toner of the present invention contains, as an external additive, a second silica particle in addition to the first silica particle, and the second silica particle is surface-modified with a silicone oil. preferable.
Hereinafter, the first and second silica particles will be described.

<First silica particle>
As described above, the first silica particle according to the present invention contains a sulfur element.
Usually, the silica particles used for the external additive are amorphous silicon dioxide, and SiO ₄ tetrahedra are solidified with irregular arrangement. Here, amorphous silicon dioxide forms a three-dimensional network and forms hard particles.
The first silica particle according to the present invention is considered to be able to divide the three-dimensional network of silicon dioxide and reduce the hardness by containing sulfur element. The sulfur element is an element of the third period having a relatively large atomic radius among non-metallic elements such as carbon element, nitrogen element and phosphorus element, and can effectively divide a three-dimensional network it is conceivable that. Further, the method of using sulfur element is also useful from the viewpoint of safety and manufacturability.
In addition, when a toner containing such first silica particles as an external additive is used, excessive damage to the surface of the photosensitive member and scratching can be suppressed, so development stability and sensitivity can be suppressed. It is considered that the suppression of wear on the body was compatible. Then, it is considered that high-quality image formation can be performed for a long time in any of high temperature and high humidity and low temperature and low humidity environment.

In the embodiment of the present invention, from the viewpoint of effectively achieving the effects of the present invention, it is preferable that the first silica particles contain a sulfur element in the silica host particles. Thereby, it is considered that the effect of dividing the three-dimensional network of silicon dioxide described above to lower the hardness of the silica particles can be effectively obtained.
Further, in the present invention, the silica base particles refer to silica particles in a state where the surface modification treatment, that is, the hydrophobization treatment is not performed.
Further, in the present invention, the term "silica particles" is used in the sense that it includes particles obtained by surface-modifying a silica base particle, silica particles in a state without surface modification (silica base particle), or a mixture thereof.

(Sulfur element contained in silica particles)
It is preferable that content of the sulfur element contained in the 1st silica particle which concerns on this invention exists in the range of 20-50000 mass ppm. By setting the content to 20 mass ppm or more, it is considered that the effect of dividing the three-dimensional network of silicon dioxide described above is effectively obtained and the effect of lowering the hardness of the silica particles is obtained. The deterioration of unevenness can be suppressed. Further, by setting the amount to 50000 mass ppm or less, the effect of the three-dimensional network division of silicon dioxide described above is not excessively increased, and the hardness of the silica particles is prevented from being excessively lowered, and the photoreceptor wear is appropriately reduced. By doing this, it is possible to suppress image contamination due to photoreceptor filming.

Moreover, as a manufacturing method of the 1st silica particle containing elemental sulfur, the method of putting a silica particle in the solution containing (1) sulfur compound, coating the solution on the surface, and drying and baking after that (solution method) and a gas (2) sulfur-containing compounds (e.g., sulfur dioxide _(SO 2)), the silicon-containing compound (e.g., silicon tetrachloride (SiCl ₄₎₎ a mixed gas of the gas flame ( In the flame | frame, the method (gas phase method) of making it react is mentioned. Among these, from the viewpoint of uniformly causing sulfur in the silica particles, it is preferable to produce by a gas phase method.

(Other elements contained in silica particles)
The first silica particles according to the present invention may also contain elements other than sulfur elements, for example, lithium element, sodium element, potassium element, beryllium element, magnesium element, in the range where the effects of the present invention can be obtained. A calcium element, a carbon element, a nitrogen element, and a phosphorus element may be contained. Further, among these elements, the first silica particles preferably contain a sodium element. When the first silica particles contain a sodium element, it is possible to obtain an effect that high quality images can be obtained without toner scattering and the like even when printing is performed with high coverage. The reason is not clear, but it is presumed that the rising of the charge is improved by the decrease in the resistance of the particles as compared with the one in which the sodium element is not contained.

The amount of elements present in the silica particles can be measured by a fluorescent X-ray analyzer, acid decomposition / inductive coupling plasma emission spectrometry, or the like. Although an example of the measuring method using acid decomposition / inductive coupling plasma emission spectrometry is described below, it is not necessarily limited to this as long as equivalent quantification can be made.
As pretreatment, the sample is dissolved using an acid selected according to the sample. The target component is eluted by selecting and using nitric acid, sulfuric acid, hydrochloric acid, hydrofluoric acid, hydrogen peroxide or the like depending on the type of the element to be measured. The decomposition solution is appropriately diluted using ultrapure water. In addition, select the most suitable melting method for metals and elements, such as alkaline melting method and combustion method.
For measurement of an element to be measured, for example, a high frequency inductively coupled plasma optical emission analyzer (ICP-OES, manufactured by SII Nano Technology Inc., SPS 3520 UV) can be used. The wavelength is not limited as long as it has no interference and high sensitivity. The calibration curve is used by adding a standard solution for chemical analysis manufactured by Kanto Chemical Co., Inc. to a decomposition solution containing no sample, and adjusting the acid concentration to the same as that of the sample solution. In addition, depending on the type of element, an optimum device such as combustion ion chromatography is selected.

(Silica particle surface)
Further, from the viewpoint of stabilizing the chargeability, it is preferable that the sulfur element not be localized on the surface of the silica particle, that is, it is preferable that the sulfur element be present only inside the silica base particle.
With respect to the amount of sulfur element on the surface of the silica particle, the element ratio of sulfur measured by the following XPS (X-ray photoelectron spectroscopy) is preferably 2 atom% or less, more preferably 1 atom% or less, and peak It is particularly preferred that (2) not be detected (0 atom%).

The amount of sulfur element on the surface of the silica particle is determined by using the X-ray photoelectron spectrometer “K-Alpha” (manufactured by Thermo Fisher Scientific Co., Ltd.) under the following analysis conditions: silicon element, carbon element, oxygen element, sulfur element The quantitative analysis of the sodium element is performed, the surface element concentration is calculated from each atomic peak area using the relative sensitivity factor, and the value of the surface element concentration (atom%) of the sulfur element is calculated. In addition, a silica particle is put in the hole (diameter 3 mm, depth 1 mm) of the measurement plate for powder, and let measurement use the thing which scratched the surface as a measurement sample.
(Measurement condition)
X-ray: Al monochrome source Acceleration: 12 kV, 6 mA
Beam system: 400 μm
Pass energy: 50 eV
Step size: 0.1 eV

(Surface modification)
It is preferable that the 1st silica particle which concerns on this invention is surface-modified by the alkyl alkoxysilane which has a structure represented by following General formula (1), a silazane, or a silicone oil.

First, an alkylalkoxysilane having a structure represented by the following general formula (1) will be described.
General formula (1): R ₁ -Si (OR ₂ ) ₃
R ₁ represents a linear alkyl group having 1 to 10 carbon atoms which may have a substituent. The carbon number is more preferably 4 or more and 8 or less. The substituent is not particularly limited as long as the effects of the present invention can be obtained, and examples thereof include a methyl group and an ethyl group. Here, by setting the carbon number of R ₁ to 1 or more and 10 or less, the external additives of the toner particles have an appropriate intermolecular force due to the interaction between the alkyl groups, and scattering hardly occurs, and the graininess is good. It is thought that it is possible to obtain various images. Further, by setting the carbon number of R ₁ to 10 or less, it is possible to prevent the interaction force between toner particles from becoming too strong and the aggregability of the external additive from becoming too high.
R ₂ represents a methyl group or an ethyl group. When the functional group of R ₂ is stericly large, the surface modification of the silica particles is difficult, and therefore, from the viewpoint of reactivity, a methyl group is more preferable. In the case where R ₂ is a hydrogen atom, since the general formula (1) is a compound having a hydroxy group, the chemical affinity with water is high, and as a result, the charge amount under high temperature and high humidity environment is high. It is unpreferable from becoming a leak point.

Examples of alkyl alkoxysilane having the structure represented by the general formula (1) described above, _{specifically, CH 3 - (CH 2)} 9 -Si (OCH 3) 3, CH 3 - (CH _{2) 9 -Si (OC 2 H} 5) 3, CH 3 - (CH 2) 7 -Si (OCH 3) 3, CH 3 - (CH 2) 7 -Si (OC 2 H 5) 3, CH 3 - _{(CH 2) 5 -Si (OCH} 3) 3, CH 3 - (CH 2) 5 -Si (OC 2 H 5) 3, CH 3 - (CH 2) 3 -Si (OCH 3) 3, CH 3 - (CH ₂ ) ₃ -Si (OC ₂ H ₅ ) ₃ , CH ₃ -CH ₂ -Si (OCH ₃ ) ₃ , CH ₃ -CH ₂ -Si (OC ₂ H ₅ ) _{3 and the} like can be mentioned, but the general formula It may be an alkyl alkoxysilane having a structure represented by (1) Well, but it is not limited to this.

  Next, silazane will be described. As the silazane, known ones can be used within the range not impairing the effects of the present invention, but from the viewpoint of obtaining an image having good scattering property and good granularity by providing an appropriate interaction force between toner particles. Hexamethyldisilazane or hexaethyldisilazane is preferred, and among these, hexamethyldisilazane is particularly preferred.

Next, silicone oil will be described. As the silicone oil, known silicone oils can be used. For example, dimethyl silicone oil, alkyl modified silicone oil, amino modified silicone oil, carboxyl modified silicone oil, epoxy modified silicone oil, fluorine modified silicone oil, alcohol modified silicone oil , Polyether modified silicone oil, methyl phenyl silicone oil, methyl hydrogen silicone oil, mercapto modified silicone oil, higher fatty acid modified silicone oil, phenol modified silicone oil, methacrylic acid modified silicone oil, polyether modified silicone oil, methyl styryl modified silicone Can use oil etc. Among these, it is preferable to use dimethyl silicone oil as the silicone oil from the viewpoint of cost and ease of handling.
The alkylalkoxysilane, silazane or silicone oil used for surface modification may be used alone or in combination of two or more.

The surface modification method of the silica particle by the above-mentioned alkyl alkoxysilane, silazane or silicone oil can use a publicly known method, for example, a dry method or a wet method can be used.
In the dry process, it is preferable to stir or mix the raw material silica particles and the surface modifier in a fluidized bed reactor. In the wet method, it is preferable to disperse raw material silica particles in a solvent to form a slurry of raw material silica particles, and then to add a surface modifier to the slurry to modify the surface of the raw material silica particles.
In the dry method or the wet method, the raw material silica particles and the surface modifier are preferably heated in the range of 100 to 400 ° C. for 0.5 to 5 hours. Such heat treatment can effectively modify silanol groups on the surface of the raw material silica particles. Further, the amount of the treatment agent (surface modifier) is not particularly limited, but is preferably 5 to 30 parts by mass, and more preferably 8 to 20 parts by mass with respect to 100 parts by mass of the raw material silica particles.

(Number average primary particle diameter)
The number average primary particle diameter of the first silica particles is preferably in the range of 10 to 200 nm, and more preferably in the range of 10 to 120 nm. By setting the number average primary particle diameter to 10 nm or more, it is difficult for the toner base particles to be buried, and the effect can be stably exhibited. Further, by setting the number average primary particle diameter to 200 nm or less, excessive wear on the surface of the photoreceptor can be easily suppressed.
The method of measuring the number average primary particle diameter of the silica particles is as follows: A photographic image taken using a scanning electron microscope (SEM) “JSM-7401F” (manufactured by Nippon Denshi Co., Ltd.) is captured by a scanner, and the image processing analysis device LUZEX AP The external additive particles (silica particles) of the photographic image are binarized using (Nireco). And the horizontal direction Feret diameter about 100 silica particles is computed, and let the average value be a number average primary particle diameter. When the number average primary particle diameter of the external additive is small and exists on the toner surface as an aggregate, the particle diameter of the primary particles forming the aggregate is to be measured.

(Content)
The content of the first silica particles according to the present invention is preferably in the range of 0.1 to 3.0% by mass, more preferably 0.1% by mass, with respect to the total amount of toner, from the viewpoint of exhibiting the effect. It is in the range of -2.5 mass%.

(Volume resistivity)
The volume resistivity of the first silica particle according to the present invention in a normal temperature and humidity environment (20 ° C., 50% RH) is preferably in the range of 1 × 10 ¹⁰ to 1 × 10 ¹⁴ Ω · cm.
By using the first silica particles having a volume resistivity of 1 × 10 ¹⁰ Ω · cm or more, the leakage of the charge amount can be suppressed even in a high temperature and high humidity environment, and the 1 × 10 ¹⁴ Ω · cm or less By using the above, overcharging can be suppressed even in a low temperature and low humidity environment, and environmental stability can be maintained.
The volume resistivity of the first silica particle according to the present invention is a value measured by the following procedure. FIG. 1 is a schematic diagram showing the configuration of a resistance measuring device 10 used when measuring the volume resistivity. The resistance measuring device 10 includes a load unit 1, a main body cell 4, a high voltage power supply 5, a resistance measuring instrument 6 and the like. In the measurement, first, the sample 2 (1 g) is put into the main cell 4, and then the load unit 1 of 1400 g is placed, and the height 3 of the sample is measured in that state. Thereafter, a high voltage power supply 5 is used to apply a DC voltage of 1000 V to the upper and lower electrode surfaces of the sample 2, and after 30 seconds, read the resistance value displayed by the resistance measuring instrument 6. The area of the electrode of this measuring instrument is 0.968 cm ² , and from these values, the volume resistivity is calculated by the following formula (1).
Formula (1): volume resistivity (Ω · cm) = {resistance (Ω) × area of electrode (cm ² )} / sample height (cm)

<Second silica particle>
As the second silica particles, silica particles produced by a known method such as a sol-gel method, a gas phase method, a melting method or the like can be used.
The second silica particles are surface modified with silicone oil as described above.
As a silicone oil, a well-known silicone oil can be used, For example, the thing similar to silicone oil which can be used by surface modification of a 1st silica particle can be used.
Moreover, silicone oil used for surface modification may be used individually by 1 type, and may use 2 or more types together.

(Number average primary particle diameter)
The number average primary particle diameter of the second silica particles is in the range of 10 to 200 nm, and more preferably in the range of 20 to 150 nm. By setting the number average primary particle diameter to 10 nm or more, the second silica particles enter between the photosensitive member and the cleaning blade, and the effect of stabilizing the contact pressure between the photosensitive member and the cleaning blade is exhibited, and the film is filled. It is possible to prevent image defects resulting from minging. Further, by setting the number average primary particle diameter to 200 nm or less, the adhesion strength to the toner base particles can be improved, and the toner base particles can be hardly separated.

(Content)
The content of the second silica particles according to the present invention is preferably in the range of 0.1 to 3.0% by mass, more preferably 0.1% by mass, with respect to the total amount of toner, from the viewpoint of exhibiting the effect. It is in the range of -2.5 mass%.

<Other external additives>
The toner of the present invention may contain, as an external additive, other known external additives in addition to the first silica particle and the second silica particle.

(Other known external additives)
As described above, the toner of the present invention may further contain other known external additives as an external additive. As a well-known external additive, the inorganic fine particle, organic fine particle, and lubricant which are mentioned later can be used, for example.

  As the inorganic fine particles, for example, inorganic oxide fine particles such as aluminum oxide fine particles and titanium oxide fine particles, inorganic stearate fine particles such as aluminum stearate fine particles and zinc stearate fine particles, or inorganic materials such as strontium titanate and zinc titanate Titanate compound fine particles and the like can be mentioned. These inorganic fine particles are subjected to gloss treatment, hydrophobic treatment, etc. with a silane coupling agent, titanium coupling agent, higher fatty acid, silicone oil, etc., in order to improve heat storage stability and environmental stability. May be

  As the organic fine particles, for example, spherical organic fine particles having a number average primary particle diameter of about 10 to 2000 nm can be used. Specifically, organic fine particles of homopolymers such as styrene and methyl methacrylate and copolymers of these can be used.

  The lubricant is used for the purpose of further improving the cleaning property and the transferability. As the lubricant, for example, metal salts of higher fatty acids can be used. Specific examples of metal salts of higher fatty acids include, for example, zinc of stearic acid, salts of aluminum, copper, magnesium, calcium and the like, zinc of oleic acid, salts of manganese, iron, copper, magnesium and the like, zinc of palmitic acid, Examples thereof include salts of copper, magnesium and calcium, zinc of linoleic acid and salts of calcium and the like, and salts of zinc and calcium of ricinoleic acid and the like.

<Binder resin>
The toner base particles according to the present invention preferably contain an amorphous resin and a crystalline resin as a binder resin. The binder resin may be composed of only an amorphous resin.

<Amorphous resin>
Amorphous resin refers to a resin that has no melting point and has a relatively high glass transition temperature (Tg) when differential scanning calorimetry (DSC) is performed. The glass transition temperature (Tg) of the non-crystalline resin is not particularly limited, but it is 25 to 60 ° C. from the viewpoint of reliably obtaining the fixing property such as low temperature fixing property and the heat resistance such as heat resistant storage property and blocking resistance. It is preferable to be within the range of In addition, the glass transition temperature (Tg) of resin employ | adopts the value measured by the method as described in an Example in this specification.

  The amorphous resin is not particularly limited as long as it has the above-mentioned characteristics, and conventionally known amorphous resins in the technical field can be used. Specific examples thereof include vinyl resin, urethane resin, urea resin, polyester resin and the like. Among them, vinyl resins are preferred from the viewpoint of high adhesion to the silica particles as chargeability.

The vinyl resin is not particularly limited as long as it is obtained by polymerizing a vinyl compound, and examples thereof include (meth) acrylic ester resins, styrene- (meth) acrylic ester resins, and ethylene-vinyl acetate resins. One of these may be used alone, or two or more of these may be used in combination.
Among the above-mentioned vinyl resins, styrene- (meth) acrylic acid ester resins are preferable in consideration of the plasticity at the time of heat fixation. Therefore, hereinafter, a styrene- (meth) acrylic acid ester resin (also referred to as a "styrene- (meth) acrylic resin" or a "styrene-acrylic resin" in the present specification) as an amorphous resin will be described. .

The styrene- (meth) acrylic resin is formed by addition polymerization of at least a styrene monomer and a (meth) acrylic acid ester monomer. The styrene monomer referred to here includes, in addition to styrene represented by the structural formula of CH ₂ CHCH—C ₆ H ₅ , one having a structure having a known side chain or a functional group in the styrene structure. In addition to the acrylic acid ester compound and methacrylic acid ester compound represented by CH ₂ CHCHCOOR (R is an alkyl group), the (meth) acrylic acid ester monomer referred to here is an acrylic acid ester derivative or methacrylic acid. It contains an ester compound having a known side chain or functional group in the structure of an ester derivative or the like. In the present specification, “(meth) acrylic acid ester monomer” is a generic term for “acrylic acid ester monomer” and “methacrylic acid ester monomer”.

Examples of styrene monomers and (meth) acrylic acid ester monomers capable of forming a styrene- (meth) acrylic resin are shown below.
Specific examples of the styrene monomer include, for example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene and 2,4-dimethylstyrene P-tert-butylstyrene, p-n-hexylstyrene, p-n-octylstyrene, p-n-nonylstyrene, p-n-decylstyrene, p-n-dodecylstyrene and the like. These styrene monomers may be used alone or in combination of two or more.

  Moreover, as a specific example of the (meth) acrylic acid ester monomer, for example, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate Acrylic acid ester monomers such as stearyl acrylate, lauryl acrylate and phenyl acrylate; methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, Stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl meta Relate, methacrylic acid esters such as dimethyl aminoethyl methacrylate. These (meth) acrylic acid ester monomers can be used alone or in combination of two or more.

  It is preferable that the content rate of the structural unit derived from the styrene monomer in styrene- (meth) acrylic resin is in the range of 40-90 mass% with respect to the whole quantity of the said resin. Moreover, it is preferable in the said resin that the content rate of the structural unit derived from the (meth) acrylic acid ester monomer is 10-60 mass% with respect to the whole quantity of the said resin.

  Furthermore, in addition to the said styrene monomer and the (meth) acrylic acid ester monomer, the styrene- (meth) acrylic resin may contain the following monomer compounds. Examples of the monomer compound include compounds having a carboxy group such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumaric acid, monoalkyl ester of maleic acid, monoalkyl ester of itaconic acid; Hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) The compound which has a hydroxyl group, such as an acrylate, is mentioned. These monomer compounds may be used alone or in combination of two or more.

It is preferable that the content rate of the structural unit derived from the said monomer compound in styrene- (meth) acrylic resin is in the range of 0.5-20 mass% with respect to the whole quantity of the said resin.
The weight average molecular weight (Mw) of the styrene- (meth) acrylic resin is preferably 10,000 to 100,000. The method for producing the styrene- (meth) acrylic resin is not particularly limited, and any polymerization initiator such as peroxide, persulfide, persulfate, or azo compound which is usually used for polymerization of the above-mentioned monomers is used. Examples of the method include polymerization by a known polymerization method such as bulk polymerization, solution polymerization, emulsion polymerization, mini-emulsion method and dispersion polymerization. In addition, generally used chain transfer agents can be used for the purpose of adjusting molecular weight. The chain transfer agent is not particularly limited, and examples thereof include alkyl mercaptans such as n-octyl mercaptan and mercapto fatty acid esters.

  The content of the styrene- (meth) acrylic resin (styrene-acrylic resin) in the binder resin is not particularly limited, but is preferably in the range of 50 to 100% by mass with respect to the total amount of the binder resin. . Since the toner base particles mainly composed of styrene- (meth) acrylic resin (styrene-acrylic resin) have high adhesion to the silica particles used as the external additive, the number of liberated silica particles can be reduced. It is possible to suppress excessive depletion of the photoreceptor surface by liberated silica particles.

<Crystalline resin>
The toner base particles according to the present invention preferably contain a crystalline resin as a binder resin. By mixing and using a crystalline resin with an amorphous resin, the crystalline resin and the amorphous resin become compatible at the time of heat fixing. As a result, low temperature fixing of the toner can be achieved, and energy saving can be achieved.
Here, the crystalline resin refers to a resin having a clear endothermic peak instead of a stepwise endothermic change in differential scanning calorimetry (DSC). A clear endothermic peak specifically means a peak whose half-width of the endothermic peak is within 15 ° C. when measured at a heating rate of 10 ° C./min in differential scanning calorimetry (DSC) Do.

The crystalline resin is not particularly limited as long as it has the above-mentioned characteristics, and conventionally known crystalline resins in the technical field can be used. Specific examples thereof include crystalline polyester resins, crystalline polyurethane resins, crystalline polyurea resins, crystalline polyamide resins, crystalline polyether resins and the like. The crystalline resin may be used alone or in combination of two or more.
Among these, it is preferable to use a crystalline polyester resin as the crystalline resin. Here, “crystalline polyester resin” is obtained by a polycondensation reaction of a carboxylic acid having two or more valences (polyvalent carboxylic acid) and a derivative thereof with an alcohol having two or more valences (polyhydric alcohol) and a derivative thereof Among known polyester resins, it is a resin that satisfies the above-mentioned endothermic characteristics.
The melting point of the crystalline polyester resin is not particularly limited, but is preferably in the range of 55 to 90 ° C., and more preferably in the range of 60 to 85 ° C. When the melting point of the crystalline polyester resin is in the above range, sufficient low temperature fixability can be obtained. The melting point of the crystalline polyester resin can be controlled by the resin composition. Moreover, in the present specification, the melting point of the resin adopts a value measured by the method described in the examples.
The number of valences of polyvalent carboxylic acid and polyhydric alcohol constituting the crystalline polyester resin is preferably 2 to 3 respectively, and particularly preferably 2 each, so in the following, the valence is 2 respectively The details of (i.e., the dicarboxylic acid component and the diol component) will be described.

As a dicarboxylic acid component, it is preferable to use an aliphatic dicarboxylic acid, and if necessary, an aromatic dicarboxylic acid may be used in combination. It is preferable to use a linear type aliphatic dicarboxylic acid. Using a linear type has the advantage of improving the crystallinity. The dicarboxylic acid components may be used alone or in combination of two or more.
Examples of aliphatic dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid Acid (dodecanedioic acid), 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid (tetradecanedioic acid), 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,16-hexadecane Dicarboxylic acid, 1,18-octadecane dicarboxylic acid, etc. are mentioned.
Among the above-mentioned aliphatic dicarboxylic acids, the dicarboxylic acid component is preferably an aliphatic dicarboxylic acid having 6 to 14 carbon atoms, and more preferably an aliphatic dicarboxylic acid having 8 to 14 carbon atoms.

Examples of aromatic dicarboxylic acids that can be used together with aliphatic dicarboxylic acids include phthalic acid, terephthalic acid, isophthalic acid, orthophthalic acid, t-butylisophthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-biphenyl Dicarboxylic acid etc. are mentioned. Among these, terephthalic acid, isophthalic acid and t-butyl isophthalic acid are preferably used from the viewpoint of easy availability and ease of emulsification.
In addition to the above dicarboxylic acids, trivalent or higher polyvalent carboxylic acids such as trimellitic acid and pyromellitic acid, anhydrides of the above carboxylic acid compounds, or alkyl esters having 1 to 3 carbon atoms may be used. .
As a dicarboxylic acid component for forming a crystalline polyester resin, the content of aliphatic dicarboxylic acid is preferably 50 mol% or more, more preferably 70 mol% or more, and still more preferably 80 mol%. It is the above, especially preferably 100 mol%. When the content of the aliphatic dicarboxylic acid in the dicarboxylic acid component is 50 mol% or more, the crystallinity of the crystalline polyester resin can be sufficiently secured.

Moreover, as a diol component, it is preferable to use an aliphatic diol, and you may use diol other than an aliphatic diol together as needed. As the aliphatic diol, it is preferable to use a linear type. Using a linear type has the advantage of improving the crystallinity. The diol component may be used alone or in combination of two or more.
As an aliphatic diol, for example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7- Heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14- Tetradecanediol, 1,18-octadecanediol, 1,20-eicosanediol neopentyl glycol and the like can be mentioned.
As a diol component, it is preferable that it is a C2-C12 aliphatic diol among the said aliphatic diols, and a C3-C10 aliphatic diol is more preferable.
As a diol which can be used with an aliphatic diol, a diol having a double bond, a diol having a sulfonic acid group and the like can be mentioned. Specifically, as the diol having a double bond, for example, 1,4-butenediol, 2-butene-1,4-diol, 3-hexene-1,6-diol, 4-octene-1,8 -Diol etc. are mentioned. Moreover, you may use a trivalent or more polyhydric alcohol as a diol which can be used with aliphatic diol. Glycerin, pentaerythritol, trimethylol propane, sorbitol etc. are mentioned as a polyhydric alcohol more than trivalence.

As a diol component for forming a crystalline polyester resin, it is preferable that content of an aliphatic diol shall be 50 mol% or more, More preferably, it is 70 mol% or more, More preferably, it is 80 mol% or more And particularly preferably 100 mol%. When the content of the aliphatic diol in the diol component is 50 mol% or more, the crystallinity of the crystalline polyester resin can be secured, and a toner excellent in low-temperature fixability can be obtained.
The weight average molecular weight (Mw) of the crystalline polyester resin is preferably 3000 to 100000, and is 4000 to 50000, from the viewpoint of obtaining both low-temperature fixability and excellent long-term heat-resistant storage stability with certainty. And more preferably 5000 to 20000. The ratio of use of the above diol component to the dicarboxylic acid component is such that the ratio [OH] of the equivalent [OH] of the hydroxy group of the diol component to the equivalent [COOH] of the carboxy group of the dicarboxylic acid component is 1. It is preferably in the range of 5/1 to 1 / 1.5, and more preferably in the range of 1.2 / 1 to 1 / 1.2.

The method for producing the crystalline polyester resin is not particularly limited, and the crystalline polyester resin can be produced by polycondensing (esterification) the dicarboxylic acid and the dialcohol using a known esterification catalyst.
Examples of catalysts usable in the production of crystalline polyester resins include alkali metal compounds such as sodium and lithium; compounds containing Group 2 elements such as magnesium and calcium; aluminum, zinc, manganese, antimony, titanium, tin, Compounds of metals such as zirconium and germanium; phosphorous compounds; phosphoric compounds; and amine compounds. Specific examples of the tin compound include dibutyltin oxide, tin octylate, tin dioctylate, and salts thereof. Examples of titanium compounds include titanium alkoxides such as tetranormal butyl titanate, tetraisopropyl titanate, tetramethyl titanate and tetrastearyl titanate; titanium acylates such as polyhydroxytitanium stearate; titanium tetraacetylacetonate, titanium lactate, titanium triethanolamide And titanium chelates such as nitrate. As a germanium compound, germanium dioxide etc. can be mentioned. Further, as the aluminum compound, oxides such as polyaluminum hydroxide, aluminum alkoxide and the like can be mentioned, and tributylaluminate etc. can be mentioned. You may use these individually by 1 type or in combination of 2 or more types.

The polymerization temperature is not particularly limited, but is preferably in the range of 150 to 250 ° C. The polymerization time is not particularly limited, but preferably in the range of 0.5 to 15 hours. During the polymerization, the reaction system may be depressurized if necessary.
When the binder resin contains a crystalline resin (preferably, a crystalline polyester resin), the content of the crystalline resin in the binder resin is not particularly limited, but is less than 50% by mass with respect to the total amount of the binder resin. The content is preferably 30% by mass or less, and particularly preferably 10% by mass or less. When the crystalline resin is a crystalline polyester resin, by setting the content to less than 50% by mass, the environmental dependence of the charge amount resulting from the hygroscopicity of the crystalline polyester resin can be reduced. On the other hand, the lower limit of the content is not particularly limited, but when the binder resin contains a crystalline resin (preferably, a crystalline polyester resin), the content is preferably 5% by mass or more. When the content of the crystalline resin is 5% by mass or more based on the total amount of the binder resin, a toner excellent in low-temperature fixability can be obtained.

<Colorant>
As a coloring agent, carbon black, a magnetic body, a dye, a pigment, etc. can be used arbitrarily.
As carbon black, channel black, furnace black, acetylene black, thermal black, lamp black or the like is used.
As the magnetic substance, ferromagnetic metals such as iron, nickel, or cobalt, alloys containing these metals, ferrite, or compounds of ferromagnetic metals such as magnetite can be used.
As a dye, C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 122, C.I. I. Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93, 95, and the like can be used, and mixtures of these can also be used.
As a pigment, C.I. I. Pigment red 5, 48: 1, 48: 3, 53: 1, 57: 1, 81: 4, 122, 139, 144, 149, 166, 177, 178, 222, C.I. I. Pigment oranges 31, 43, C.I. I. Pigment yellows 14, 17, 74, 93, 94, 138, 155, 180, 185, C.I. I. Pigment green 7, C.I. I. Pigment Blue 15: 3, 15: 4, or 60 can be used, and mixtures thereof can also be used.

<Mold release agent (wax)>
As the release agent, various known waxes can be used.
Examples of waxes include polyolefin waxes such as polyethylene wax and polypropylene wax, branched hydrocarbon waxes such as microcrystalline wax, long chain hydrocarbon waxes such as paraffin wax and sasol wax, dialkyls such as distearyl ketone Ketone wax, carnauba wax, montan wax, behenyl behenate, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18-octadecanediol di Ester-based waxes such as stearate, tristearyl trimellitate, distearyl maleate, ethylenediamine behenylamide, trimellitic acid tristearyla Such as amide-based waxes such as de the like.
The content of the release agent is preferably in the range of 0.1 to 30 parts by mass, and more preferably in the range of 1 to 10 parts by mass with respect to 100 parts by mass of the binder resin. These can be used 1 type or in combination of 2 or more types. Further, the melting point of the releasing agent is preferably in the range of 50 to 95 ° C. from the viewpoint of the low temperature fixing property and the releasing property of the toner in the electrophotography.

<Charge control agent>
In addition, a charge control agent can be added to the toner base particles according to the present invention as required. As the charge control agent, various known ones can be used.
As the charge control agent, various known compounds which can be dispersed in an aqueous medium can be used. Specifically, nigrosine dyes, metal salts of naphthenic acids or higher fatty acids, alkoxylated amines, fourth compounds And ammonium salt compounds, azo metal complexes, salicylic acid metal salts, or metal complexes thereof.

  The content of the charge control agent is preferably in the range of 0.1 to 10 parts by mass, and more preferably in the range of 0.5 to 5 parts by mass with respect to 100 parts by mass of the binder resin.

<Particle size of toner base particle>
As the particle diameter of the toner base particles, the volume-based median diameter (D50) is preferably in the range of 3 to 10 μm, and more preferably in the range of 4 to 7 μm.
Within the above range, high reproducibility can be obtained even with a very minute dot image of 1200 dpi level.
The average particle diameter of the toner particles can be controlled by the concentration of the coagulant used at the time of production, the addition amount of the organic solvent, the fusion time, the fusion temperature, the composition of the binder resin, etc.

The volume-based median diameter of toner base particles is the median diameter in the volume particle size distribution, and it is measured and calculated using an apparatus in which a computer system for data processing is connected to "Multisizer 3 (manufactured by Beckman Coulter Co.)" can do.
As a measurement procedure, for example, 0.02 mL of toner particles is dissolved in 20 mL of a surfactant solution (for the purpose of dispersing toner particles, for example, a surfactant solution in which a neutral detergent containing a surfactant component is diluted 10 times with pure water) The mixture is subjected to ultrasonic dispersion for 1 minute to prepare a toner mother particle dispersion. The toner mother particle dispersion is pipetted into a beaker containing ISOTON II (manufactured by Beckman Coulter, Inc.) in a sample stand until the measurement density becomes 5 to 10%. Here, by setting the concentration range, reproducible measurement values can be obtained. Then, the measurement particle count number is set to 25000, the aperture diameter of Multisizer 3 (manufactured by Beckman Coulter, Inc.) is set to 100 μm, the frequency range of 2 to 60 μm is divided into 256, and the frequency number is calculated. The particle diameter of 50% from the larger one of the integrated fraction is taken as the volume-based median diameter.

<Average Roundness of Toner Base Particles>
The toner base particles preferably have an average circularity in the range of 0.930 to 1.000, and more preferably in the range of 0.950 to 0.995, from the viewpoint of the stability of the charging characteristics. .
If the average circularity is within the above range, it is difficult for the individual toner base particles to be broken. As a result, contamination of the surface of the carrier particles can be suppressed to stabilize the chargeability of the toner, and the image quality of the formed image can be enhanced.

The average circularity of the toner base particles is a value measured using a flow type particle image analyzer "FPIA-3000" (manufactured by Sysmex Corporation). Specifically, the toner base particles are wetted with a surfactant aqueous solution, subjected to ultrasonic dispersion for 1 minute, dispersed, and then HPF under the measurement condition HPF (high magnification imaging) mode using “FPIA-3000”. The number of detections is measured at an appropriate concentration of 3000 to 10000. Within this range, reproducible measurement values can be obtained. The roundness is calculated by the following equation.
Formula: Toner base particle circularity = (peripheral length of a circle having the same projected area as the particle image) / (peripheral length of particle projection image)
Here, the average circularity of the toner base particles is an arithmetic average value obtained by adding the circularity of each particle and dividing it by the total number of particles measured.

<Core-shell structure>
The toner particles can be used as the toner as they are, but the toner particles having a multi-layered structure such as a core-shell structure comprising the core particles and the shell layer covering the surface as the core particles Good. The shell layer may not cover the entire surface of the core particle, and the core particle may be partially exposed. The cross section of the core-shell structure can be confirmed by a known observation means such as, for example, a transmission electron microscope (TEM) or a scanning probe microscope (SPM).

  In the case of the core-shell structure, characteristics such as the glass transition point, the melting point and the hardness can be made different between the core particle and the shell layer, and the toner particle can be designed according to the purpose. For example, a resin having a relatively high glass transition point (Tg) is coagulated and fused to the surface of a core particle having a binder resin, a coloring agent, a release agent, etc. and having a relatively low glass transition point (Tg) To form a shell layer. The shell layer preferably contains an amorphous resin.

<Two-component developer>
A two-component developer can be obtained by mixing the toner according to the present invention and the following carrier particles. The mixing apparatus used for mixing is not particularly limited, and examples thereof include Nauta mixer, W cone and V-type mixer.
The content (toner concentration) of the toner in the two-component developer is not particularly limited, but is preferably 4.0 to 8.0% by mass.

<Carrier particles>
The carrier particles are made of magnetic material, and known ones can be used. For example, as carrier particles, coated carrier particles having core particles made of a magnetic substance and a layer of a coating material that covers the surface of the core particles, or fine powder of magnetic substance dispersed in resin And resin-dispersed carrier particles. The carrier particles are preferably the above-mentioned coated carrier particles from the viewpoint of suppressing the adhesion of the carrier particles to the photosensitive member. The coated carrier particles will be described below.

The core particle (carrier core) constituting the coated carrier particle is composed of a magnetic substance, for example, a substance which is strongly magnetized by a magnetic field. Examples of the magnetic substance include metals exhibiting ferromagnetism such as iron, nickel and cobalt, alloys or compounds containing these metals, and alloys exhibiting ferromagnetism by heat treatment. The said magnetic body can be used individually by 1 type or in combination of 2 or more types.
Examples of the above-mentioned metals exhibiting ferromagnetism and alloys or compounds containing these metals include iron, ferrites represented by the following formula (a), and magnetite represented by the following formula (b). M in formulas (a) and (b) represents one or more metals selected from the group consisting of Mn, Fe, Ni, Co, Cu, Mg, Zn, Cd and Li.

Formula (a): MO · Fe ₂ O ₃
Formula (b): MFe ₂ O ₄
Moreover, Heusler alloys, such as manganese- copper- aluminum and manganese- copper- tin, and chromium dioxide etc. are mentioned as an alloy which shows ferromagnetism by heat-processing.

In general, the specific gravity of the coated carrier particle is smaller than the specific gravity of the metal constituting the core particle. Therefore, among the above, it is preferable to use various ferrites as core particles from the viewpoint of reducing the impact force of stirring in the developing container.
A coated carrier particle can be obtained by coating the surface of the core particle with a coating material (carrier coat resin). At this time, as the covering material, a known resin used for covering core material particles can be used. Examples of such resins include polyolefin resins such as polyethylene and polypropylene; polystyrene resins; (meth) acrylic resins such as polymethyl methacrylate, polyacrylonitrile, polyvinyl acetate, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride and the like Resin and polyvinylidene resin; copolymer resin such as vinyl chloride-vinyl acetate copolymer or styrene-acrylic acid copolymer; silicone resin comprising organosiloxane bond or modified resin thereof (eg, alkyd resin, polyester resin, epoxy) Resin, modified resin by polyurethane etc .; fluorine resin such as polyvinyl fluoride; polyamide resin; polyester resin; polyurethane resin; polycarbonate resin; urea-formaldehyde resin And the like epoxy resins; amino resins such as.

  The coating material is preferably a resin having a cycloalkyl group from the viewpoint of reducing the moisture adsorption of the carrier particles and the viewpoint of enhancing the adhesion between the coating material and the core material particles. Examples of the cycloalkyl group include cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group and cyclodecyl group. Among these, from the viewpoint of adhesion between the coating material and the core particles (preferably ferrite particles), a cyclopentyl group or a cyclohexyl group is preferable, and a cyclohexyl group is more preferable.

The weight average molecular weight (Mw) of the carrier coat resin as the covering material is not particularly limited, but is preferably in the range of 10000 to 800,000 and more preferably in the range of 10000 to 750,000. In addition, the said weight average molecular weight (Mw) can be measured by the method using the GPC apparatus as described in the molecular weight measurement of the crystalline resin of an Example. The content of the constituent unit having a cycloalkyl group in the resin is, for example, 10 to 90% by mass. The content of the structural unit having a cycloalkyl group in the resin can be determined, for example, by thermal decomposition-gas chromatography / mass spectrometry (Py-GC / MS) or ¹ H-NMR.
By applying mechanical impact force or heat to the coating material and the core material particles, the coating material can be adhered and fixed to the core material particles, whereby a carrier can be obtained.

The volume-based median diameter of the carrier particles is preferably 15 to 100 μm, and more preferably 25 to 80 μm.
The median diameter of the carrier particles is measured by a wet method using a laser diffraction type particle size distribution measuring apparatus "HELOS KA" (manufactured by Nippon Laser Co., Ltd.). Specifically, first, an optical system with a focal position of 200 mm is selected, and the measurement time is set to 5 seconds. Then, magnetic particles for measurement are added to a 0.2% aqueous solution of sodium dodecyl sulfate, and dispersed for 3 minutes using an ultrasonic cleaner "US-1" (manufactured by As One Corporation) to prepare a sample dispersion for measurement. Then, several drops of this are supplied to the laser diffraction type particle size distribution measuring device, and the measurement is started when the sample concentration gauge reaches the measurable region. With respect to the obtained particle size distribution, a cumulative distribution is created from the small diameter side with respect to the particle size range (channel), and the particle size at which the cumulative 50% is obtained is defined as the volume average particle size.

[Method of producing toner for developing electrostatic image]
The method for producing the toner of the present invention is not particularly limited, and known methods such as kneading and pulverizing method, suspension polymerization method, emulsion aggregation method, dissolution suspension method, polyester elongation method, dispersion polymerization method may be mentioned. Among these, from the viewpoint of the uniformity of the particle diameter and the controllability of the shape, it is preferable to adopt the emulsion aggregation method.

In the emulsion aggregation method, a dispersion of binder resin particles (hereinafter, also referred to as "binder resin particles") dispersed by a surfactant or a dispersion stabilizer may be used as a colorant particle (if necessary). The toner particles are mixed with a dispersion of “colorant particles”, coagulated to a desired toner particle diameter, and fused between binder resin particles to perform shape control, thereby producing toner particles. How to Here, the particles of the binder resin may optionally contain a release agent, a charge control agent, and the like.
An example is shown below about the preferable manufacturing method of the toner based on this invention.

(1) Step of preparing a colorant particle dispersion in which colorant particles are dispersed in an aqueous medium (2) Amorphous resin particles containing an internal additive, if necessary, are dispersed in the aqueous medium Step of preparing a dispersion of amorphous resin particles (3) Step of preparing a dispersion of crystalline resin particles in which crystalline resin particles are dispersed in an aqueous medium (4) Dispersion of colorant particles, non-crystallization Resin particle dispersion and crystalline resin particle dispersion are mixed to obtain a resin particle dispersion for aggregation, and colorant particles, non-crystalline resin particles and crystalline resin particles are aggregated and melted in the presence of an aggregating agent Of forming toner base particles (cohesion / fusion process)
(5) Process of removing toner base particles from the dispersion of toner base particles by filtration to remove surfactant and the like (washing step)
(6) Step of Drying Toner Base Particles (Drying Step)
(7) Process of Adding External Additive to Toner Base Particles (External Additive Treatment Process)

  In addition, the non-crystalline resin particles containing an internal additive as required in (2) described above may be prepared to have a multilayer structure of two or more layers. For example, in the case of producing amorphous resin particles having a three-layer structure, in three steps of first stage polymerization (formation of inner layer), second stage polymerization (formation of intermediate layer) and third stage polymerization (formation of outer layer) It can produce by performing the polymerization reaction which divides and synthesize | combines an amorphous resin particle. Further, here, in the respective polymerization reactions of the first stage polymerization to the third stage polymerization, by changing the composition of the polymerizable monomer, it is possible to produce non-crystalline resin particles of a three-layer constitution having different compositions. Also, for example, in any of the first-stage polymerization to the third-stage polymerization, an appropriate internal additive can be obtained by carrying out the synthesis reaction of the amorphous resin in the state of containing an appropriate internal additive such as a mold release agent. Can be formed into a three-layered amorphous resin particle.

  In addition, the toner particles may have a core-shell structure including toner particles as core particles and a shell layer covering the surface of the core particles. The toner particles having a core-shell structure are prepared by first aggregating and fusing the binder resin particles for core particles and the colorant particles to prepare core particles, and then, for the shell layer in the dispersion of core particles. The binder resin particles are added to the core particle surface to aggregate and fuse the binder resin particles for shell layer on the core particle surface to form a shell layer covering the core particle surface.

<External processing>
A mechanical mixing device can be used for the external additive mixing process of the external additive to the toner base particles. A Henschel mixer, a Nauta mixer, a Turbula mixer etc. can be used as a mechanical mixing apparatus. Among them, a mixing device capable of applying a shearing force to particles to be treated like a Henschel mixer may be used to perform mixing processing such as prolonging the mixing time or increasing the rotational peripheral speed of the stirring blade. In addition, when using a plurality of types of external additives, the toner particles may be mixed with all the external additives at once, or may be divided and mixed in multiple times according to the external additives. It is also good.
The method of mixing external additives is the degree of crushing or adhesion strength of external additives by controlling the mixing strength, that is, the peripheral speed of the stirring blade, the mixing time, the mixing temperature, etc., using the above-mentioned mechanical mixing device. Can be controlled.

  EXAMPLES Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

[Preparation of Silica Base Particles 1 to 9]
<Measurement of the amount of elements in silica particles>
The contents of sulfur element and sodium element in silica particles described later were measured as follows.
First, as pretreatment, silica particles were subjected to acid decomposition in a closed-type microwave decomposition apparatus "ETHOS1, manufactured by Milestone General Co., Ltd.". If there is an undegraded substance, the target component is eluted using hydrochloric acid, nitric acid, hydrogen peroxide or the like. The decomposition solution was appropriately diluted using ultrapure water. For the measurement of the element amount, a high frequency inductively coupled plasma emission analyzer (ICP-OES, manufactured by SII Nano Technology, SPS 3520 UV) was used. The calibration curve was used by adding a standard solution for chemical analysis made by Kanto Chemical Co., Inc. to a decomposition solution containing no sample, and adjusting it to have the same acid concentration as the sample solution.

<Production of Silica Base Particle 1>
An oxygen-hydrogen flame with a flame temperature of 2000 ° C, together with an inert gas (nitrogen gas), at a ratio of 100: 0.05 of silicon tetrachloride (SiCl ₄ ) gas and sulfur dioxide (SO ₂ ) gas vaporized at 200 ° C. Sprayed into and hydrolyzed at high temperature. After cooling, it was collected by a filter to obtain a powder of sulfur-containing silica particles. Furthermore, after 8 g of a 5% NaOH solution was sprayed in a mist form on 100 g of the obtained powder, the powder was heated to about 900 ° C. to remove adhering chloride, thereby producing a silica base particle 1. The content of sulfur element in the silica host particle 1 was 20 mass ppm, and the content of sodium element was 4,000 mass ppm. In addition, the BET specific surface area of the obtained silica base particle 1 was 130 g / m ² , and the number average primary particle diameter calculated using a scanning electron microscope (SEM) was 20 nm.

<Preparation of Silica Base Particle 2>
A silica base particle 2 was produced in the same manner as the method of producing the silica base particle 1, except that the ratio of silicon tetrachloride (SiCl ₄ ) gas to sulfur dioxide (SO ₂ ) gas was changed to 100: 5.
The content of sulfur element in the silica host particle 2 was 2000 mass ppm, and the content of sodium element was 4000 mass ppm. In addition, the BET specific surface area of the obtained silica base particle 2 was 130 g / m ² , and the number average primary particle diameter calculated using a scanning electron microscope (SEM) was 20 nm.

<Preparation of Silica Base Particle 3>
Silica base particles 3 were produced in the same manner as the silica base particles 1 except that the ratio of silicon tetrachloride (SiCl ₄ ) gas to sulfur dioxide (SO ₂ ) gas was changed to 100: 25. The content of sulfur element in the silica host particle 3 was 50000 mass ppm, and the content of sodium element was 4000 mass ppm. In addition, the BET specific surface area of the obtained silica base particles 3 was 130 g / m ² , and the number average primary particle diameter calculated using a scanning electron microscope (SEM) was 20 nm.

Preparation of Silica Base Particles 4
In an oxygen-hydrogen flame with a flame temperature of 2000 ° C. together with an inert gas (nitrogen gas) in a ratio of 100: 5 of silicon tetrachloride (SiCl ₄ ) gas and sulfur dioxide (SO ₂ ) gas vaporized at 200 ° C. Sprayed to high temperature hydrolysis. After cooling, it was collected by a filter to obtain a powder of sulfur-containing silica particles. Furthermore, 100 g of the obtained powder was heated to about 900 ° C. to remove adhering chloride, and silica base particles 4 were produced. The content of elemental sulfur in the silica host particles 4 was 2,000 ppm by mass, and sodium was not contained. The BET specific surface area of the obtained silica base particles 4 was 130 g / m ² , and the number average primary particle diameter calculated using a scanning electron microscope (SEM) was 20 nm.

<Preparation of Silica Base Particles 5>
In an oxygen-hydrogen flame with a flame temperature of 2000 ° C. together with an inert gas (nitrogen gas) in a ratio of 100: 5 of silicon tetrachloride (SiCl ₄ ) gas and sulfur dioxide (SO ₂ ) gas vaporized at 200 ° C. Sprayed to high temperature hydrolysis. After cooling, it was collected by a filter to obtain a powder of sulfur-containing silica particles. Furthermore, 100 g of 5% NaOH solution was sprayed in a mist form on 100 g of the obtained powder, and then heated to about 900 ° C. to remove adhering chloride, thereby producing a silica base particle 5. The content of sulfur element in the silica host particle 5 was 2000 mass ppm, and the content of sodium element was 50000 mass ppm. The BET specific surface area of the obtained particles was 130 g / m ² , and the number average primary particle diameter calculated using a scanning electron microscope (SEM) was 20 nm.

<Preparation of Silica Base Particles 6>
In an oxygen-hydrogen flame with a flame temperature of 2000 ° C. together with an inert gas (nitrogen gas) in a ratio of 100: 5 of silicon tetrachloride (SiCl ₄ ) gas and sulfur dioxide (SO ₂ ) gas vaporized at 200 ° C. Sprayed to high temperature hydrolysis. After cooling, it was collected by a filter to obtain sulfur-containing silica particles. Furthermore, after 8 g of a 5% KOH solution was sprayed in a mist form on 100 g of the obtained powder, the powder was heated to about 900 ° C. to remove adhering chloride, and silica base particles 6 were produced. The content of sulfur element of the silica host particle 6 was 2000 mass ppm, and the content of potassium element was 4000 mass ppm. The BET specific surface area of the obtained silica base particle 6 was 130 g / m ² , and the number average primary particle diameter calculated using a scanning electron microscope (SEM) was 20 nm.

<Preparation of Silica Base Particles 7>
In an oxygen-hydrogen flame with a flame temperature of 2000 ° C. together with an inert gas (nitrogen gas) in a ratio of 100: 5 of silicon tetrachloride (SiCl ₄ ) gas and sulfur dioxide (SO ₂ ) gas vaporized at 200 ° C. Sprayed to high temperature hydrolysis. After cooling, it was collected by a filter to obtain a powder of sulfur-containing silica particles. Furthermore, after 8 g of a 5% LiOH solution was sprayed in a mist form on 100 g of the obtained powder, the powder was heated to about 900 ° C. to remove adhering chloride, and silica base particles 7 were produced. The content of sulfur element in the silica host particle 7 was 2000 mass ppm, and the content of lithium element was 4000 mass ppm. The BET specific surface area of the obtained silica base particle 7 was 130 g / m ² , and the number average primary particle diameter calculated using a scanning electron microscope (SEM) was 20 nm.

<Preparation of Silica Base Particle 8>
Silicon tetrachloride (SiCl ₄ ) gas vaporized at 200 ° C. was sprayed with an inert gas (nitrogen gas) into an oxygen-hydrogen flame at a flame temperature of 2000 ° C. to perform high temperature hydrolysis. After cooling, it was collected by a filter to obtain a powder of silica matrix particles. Furthermore, after 8 g of a 5% NaOH solution was sprayed in a mist form on 100 g of the obtained powder, the powder was heated to about 900 ° C. to remove adhering chloride, and a silica base particle 8 was produced. The silica host particle 8 contained no sulfur, and the content of the sodium element was 4000 mass ppm. The BET specific surface area of the obtained silica base particles 8 was 130 g / m ² , and the number average primary particle diameter calculated using a scanning electron microscope (SEM) was 20 nm.

<Preparation of Silica Base Particles 9>
Silicon tetrachloride (SiCl ₄ ) gas vaporized at 200 ° C. was sprayed with an inert gas (nitrogen gas) into an oxygen-hydrogen flame at a flame temperature of 2000 ° C. to perform high temperature hydrolysis. After cooling, it was collected by a filter to obtain a powder of silica matrix particles. Furthermore, 100 g of the obtained powder was heated to about 900 ° C. to remove adhering chloride, and silica base particles 9 were produced. The silica host particles 9 contained neither sulfur nor sodium. The BET specific surface area of the obtained silica base particles 9 was 130 g / m ² , and the number average primary particle diameter calculated using a scanning electron microscope (SEM) was 20 nm.

[Preparation of Silica Particles 1 to 12]
Silica particles 1 to 12 were produced as follows. As described later, the silica particles 1 to 11 were used as the first silica particles, and the silica particles 12 were used as the second silica particles.
<Preparation of Silica Particles 1>
100 parts by mass of the silica base particle 1 was placed in a reaction vessel, and 2.5 parts by mass of water was sprayed while stirring under a nitrogen atmosphere. To this, 15 parts by mass of hexamethyldisilazane (HMDS), which is a surface modifier, and 1.0 parts by mass of diethylamine are sprayed, heated and stirred at 180 ° C. for 1 hour, and then cooled to obtain hydrophobic silica particles 1. The

<Preparation of Silica Particles 2 to 9>
Silica particles 2 to 9 were produced in the same manner as in the method for producing the silica particles 1 except that the silica base particles 1 were changed to the silica base particles 2 to 9.

<Preparation of Silica Particles 10>
100 parts by mass of the silica base particles 2 were placed in a reaction vessel, and 5 parts by mass of polydimethylsiloxane (PDMS), which is a surface modifier, was sprayed while stirring under a nitrogen atmosphere. While stirring was continued, the temperature was raised from room temperature to 340 ° C., and held there for 30 minutes. By cooling this, hydrophobic silica particles 10 were obtained.

<Preparation of Silica Particles 11>
100 parts by mass of the silica base particle 2 was put in a reaction vessel, and 2.5 parts by mass of water was sprayed while stirring under a nitrogen atmosphere. Thereto, 15 parts by mass of n-octyltrimethoxysilane as a surface modifier and 1.0 parts by mass of diethylamine were sprayed, and the mixture was heated and stirred at 180 ° C. for 1 hour, and then cooled to obtain hydrophobic silica particles 11 .

<Preparation of Silica Particles 12>
100 parts by mass of silica particles (Aerosil (registered trademark) OX 50, number average primary particle diameter 40 nm) manufactured by a vapor phase method which is not subjected to a commercial surface modification treatment is placed in a reaction vessel, Under the atmosphere, 5 parts by mass of polydimethylsiloxane (PDMS) which is a surface modifier was sprayed while stirring. While stirring was continued, the temperature was raised from room temperature to 340 ° C., and held there for 30 minutes. By cooling this, hydrophobic silica particles 12 were obtained.

<Measurement of sulfur element amount on the surface of silica particles 1 to 12>
The amount of sulfur element on the surface of each silica particle is measured using an X-ray photoelectron spectrometer "K-Alpha" (manufactured by Thermo Fisher Scientific Co., Ltd.) under the following analysis conditions: silicon element, carbon element, oxygen element, sulfur element The surface element concentration was calculated using the relative sensitivity factor from each atomic peak area, and the value of the surface element concentration (atom%) of sulfur element was calculated. The measurement was carried out in a state where the silica particle powder was put in the holes (diameter 3 mm, depth 1 mm) of the measurement plate for powder and the surface was rubbed.
(Measurement condition)
X-ray: Al monochrome source Acceleration: 12 kV, 6 mA
Beam system: 400 μm
Pass energy: 50 eV
Step size: 0.1 eV

  Moreover, as a result of the said measurement, in all the silica particles 1-12, the amount of sulfur elements in the silica particle surface was 0 atom%.

<Measurement of Volume Resistivity of Silica Particles 1 to 12>
The volume resistivity of each of the silica particles in a normal temperature and normal humidity environment (20 ° C., 50% RH) was measured. The measured values are shown in Table I.
The volume resistivity of the silica particles was measured by a resistance measuring device 10 as shown in FIG. The resistance measuring device 10 includes a load unit 1, a main body cell 4, a high voltage power supply 5, a resistance measuring instrument 6 and the like. In the measurement, first, a sample 2 (1 g) was charged into the main cell 4, and then a 1400 g load unit 1 was placed, and the height 3 of the sample was measured in that state. Thereafter, using a high voltage power supply 5, a DC voltage of 1000 V was applied to the upper and lower electrode surfaces of the sample 2, and after 30 seconds, the resistance value displayed by the resistance measuring instrument 6 was read. The area of the electrode of this measuring instrument was 0.968 cm ² , and the volume resistivity was calculated by the following formula (1) from these values.
Formula (1): volume resistivity (Ω · cm) = {resistance (Ω) × area of electrode (cm ² )} / sample height (cm)

[Production of Toner Base Particle 1]
Preparation of Aqueous Dispersion of Amorphous Resin Fine Particles (Releasing Agent-Containing Styrene-Acrylic Resin Fine Particles)
[First Stage Polymerization]
8 parts by mass of sodium dodecyl sulfate and 3000 parts by mass of ion-exchanged water are charged into a 5 L reaction vessel equipped with an agitator, temperature sensor, cooling pipe and nitrogen introduction device, and the mixture is stirred at a stirring speed of 230 rpm under nitrogen stream. The temperature was raised to 80 ° C. After the temperature rise, 10 parts by mass of potassium persulfate dissolved in 200 parts by mass of ion exchanged water is added, and the liquid temperature is again adjusted to 80 ° C.,
480 parts by mass of styrene,
250 parts by mass of n-butyl acrylate,
68 parts by mass of methacrylic acid,
2.1 parts by mass of n-octyl-3-mercaptopropionate,
The monomer mixture liquid consisting of the above was added dropwise over 1 hour, and then polymerization was carried out by heating and stirring at 80 ° C. for 2 hours to prepare a dispersion liquid of resin fine particles (x1).

Second Stage Polymerization
A solution of 7 parts by mass of sodium polyoxyethylene (2) dodecyl ether sulfate in 2000 parts by mass of ion-exchanged water is charged into a 5-liter reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introducing device. After heating to ° C
260 parts by mass of a dispersion (x1) of resin fine particles,
284 parts by mass of styrene (St),
142 parts by mass of n-butyl acrylate (BA),
6 parts by mass of methacrylic acid (MAA),
1.5 parts by mass of n-octyl-3-mercaptopropionate,
Release agent: 190 parts by mass of behenyl behenate (melting point 73 ° C.),
A solution obtained by dissolving at 90 ° C. a monomer consisting of the above and a mold release agent is added, and mixed and dispersed for 1 hour by a mechanical disperser “Claremix” (manufactured by M. Technics Co., Ltd.) having a circulation path, A dispersion containing emulsified particles (oil droplets) was prepared.
Then, an initiator solution in which 6 parts by mass of potassium persulfate is dissolved in 200 parts by mass of ion exchanged water is added to the dispersion, and the system is heated and stirred at 84 ° C. for 1 hour to carry out polymerization A dispersion (x2) of resin fine particles was prepared.

[Third Stage Polymerization]
Further, a solution of 11 parts by mass of potassium persulfate dissolved in 400 parts by mass of ion-exchanged water is added to the dispersion liquid (x 2) of resin fine particles, and a temperature condition of 82 ° C.
350 parts by mass of styrene (St),
155 parts by mass of n-butyl acrylate (BA),
37 parts by mass of acrylic acid (AA),
15 parts by mass of n-octyl-3-mercaptopropionate,
The monomer mixture consisting of the above was added dropwise over 1 hour. After completion of the dropwise addition, polymerization is carried out by heating and stirring for 2 hours, then cooled to 28 ° C., a 5 mol / liter aqueous solution of sodium hydroxide is added to adjust the pH to 7.0, and it consists of a vinyl resin An aqueous dispersion (SA-1) of amorphous resin fine particles was prepared.
In the aqueous dispersion (SA-1) of the obtained amorphous resin fine particles, the volume-based median diameter of the amorphous resin fine particles is 220 nm, the glass transition temperature (Tg) is 55 ° C., and the weight average molecular weight (Mw) is It was 27,000.

<Synthesis of Crystalline Resin (Crystalline Polyester Resin)>
Polyvalent carboxylic acid: 258.0 parts by mass of octanedioic acid (molecular weight 174.2) and polyhydric alcohol: 1, 8-octanediol in a reaction vessel equipped with a stirring device, a temperature sensor, a cooling pipe and a nitrogen introducing device 192.0 parts by mass of (molecular weight 146.2) were charged. As a catalyst, 0.7 parts by mass of dibutyltin oxide and 0.4 parts by mass of hydroquinone were added, and reacted at 170 ° C. for 5 hours under a nitrogen gas atmosphere. Furthermore, the reaction was performed at 170 ° C. until a resin having a desired melting point at 3.3 kPa was obtained, to obtain a crystalline resin (C1).
The crystalline resin (C1) was measured by DSC at a temperature rising rate of 10 ° C./minute to find that it had a clear peak, the peak top temperature was 70 ° C., and the weight average molecular weight was 15,000. In addition, a clear peak means the peak whose half value width of an endothermic peak is 15 degrees C or less at the time of measuring with the temperature increase rate of 10 degrees C / min.

Preparation of aqueous dispersion of crystalline resin fine particles (crystalline polyester resin fine particles)
300 parts by mass of a crystalline resin (C1) was melted and transferred in a molten state at a transfer speed of 100 parts by mass per minute to an emulsifying and dispersing machine "Cavitron CD1010" (manufactured by Eurotech Co., Ltd.). At the same time as the transfer of the crystalline resin (C1) in the molten state, with respect to the emulsifying and dispersing machine, dilute ammonia water having a concentration of 0.37 mass% obtained by diluting the reagent ammonia water with ion exchange water in the aqueous solvent tank. It was transferred at a transfer rate of 0.1 liter per minute while heating to 100 ° C. with a heat exchanger. Then, the emulsifying and dispersing machine was operated at a rotational speed of 60 Hz of a rotor and a pressure of 5 kg / cm ² to prepare a crystalline resin fine particle dispersion (CA-1). Diluted ammonia water was added so that the degree of neutralization was 54%. The dispersed particle diameter of the crystalline resin particles in the crystalline resin particle dispersion (CA-1) was 151.0 nm as a volume-based median diameter.

In addition, after converting the quantity of the ammonia water used for neutralization into the mass (g) of potassium hydroxide (KOH) used for neutralization, the neutralization degree is a value calculated by the following formula as a neutralization degree It is (%).
Degree of neutralization (%) = [(amount of KOH used for neutralization [g]) / (amount of KOH capable of neutralizing 100% of terminal of crystalline resin (crystalline polyester resin) [g]) × 100

<Synthesis of Amorphous Resin (Amorphous Polyester Resin)>
112 parts by mass of terephthalic acid (TPA),
6 parts by mass of trimellitic acid (TMA),
12 parts by mass of fumaric acid (FA),
60 parts by mass of adipic acid,
Bisphenol A propylene oxide adduct (BPA · PO)
290 parts by mass,
Bisphenol A ethylene oxide adduct (BPA, EO)
55 parts by mass,
Is placed in a reaction vessel equipped with a stirrer, a thermometer, a cooling pipe and a nitrogen gas introduction pipe, and after replacing the inside of the reaction vessel with dry nitrogen gas, 0.1 part by mass of titanium tetrabutoxide is added, and nitrogen gas is added. The polymerization reaction was carried out for 9 hours while stirring at 180 ° C. under air flow. Furthermore, 0.2 parts by mass of titanium tetrabutoxide is added, and the temperature is raised to 220 ° C. and polymerization is carried out for 6 hours while stirring, then the pressure in the reaction vessel is reduced to 1333.2 Pa, and the reaction is carried out under reduced pressure. Amorphous resin (A1) was obtained by carrying out.
The glass transition point (Tg) of this amorphous resin (A1) was 53 ° C., and the weight average molecular weight (Mw) was 25,000.

Preparation of Aqueous Dispersion of Amorphous Resin Fine Particles (Amorphous Polyester Resin Fine Particles)
An aqueous solution obtained by dissolving 200 parts by mass of an amorphous resin (A1) in 200 parts by mass of ethyl acetate and then dissolving polyoxyethylene lauryl ether sodium sulfate in 800 parts by mass of ion-exchanged water to a concentration of 1.3% by mass And dispersed using an ultrasonic homogenizer. After removing ethyl acetate under reduced pressure of this solution, the solid concentration was adjusted to 20% by mass. In this way, an amorphous resin fine particle dispersion (AA-1) was prepared in which the fine particles of the amorphous resin (A1) were dispersed in the aqueous medium. The volume-based median diameter of the fine particles of the amorphous resin (A1) in the dispersion was 200 nm.

<Preparation of fine particle dispersion of release agent>
As a mold release agent, 200 parts by mass of behenyl behenate (melting point: 73 ° C.) was heated to 95 ° C. and dissolved. This was further charged into a surfactant aqueous solution dissolved in 800 parts by mass of ion exchanged water so that sodium alkyldiphenyletherdisulfonate had a concentration of 3% by mass, and then dispersion treatment was performed using an ultrasonic homogenizer. The solid concentration was adjusted to 20% by mass. Thus, a release agent fine particle dispersion (Wax 1) in which release agent fine particles were dispersed in an aqueous medium was prepared.
The volume-based median diameter of the releasing agent particles in the releasing agent particle dispersion (Wax 1) was measured using a microtrack particle size distribution measuring apparatus “Microtrack UPA-150” (manufactured by Nikkiso Co., Ltd.) and was 150 nm. .

Preparation of Colorant Particle Dispersion
While stirring a solution prepared by dissolving 90 parts by mass of sodium dodecyl sulfate in 1600 parts by mass of ion exchange water, 420 parts by mass of carbon black "Regal 330R" (manufactured by Cabot Corporation) is gradually added, and then a stirring apparatus "Clairemix" The colorant fine particle dispersion (1) was prepared by dispersion treatment using “M.TM. The particle diameter of the colorant particles in the colorant particle dispersion (1) was measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.).

<Production of Toner Base Particle 1>
Crystalline resin fine particle dispersion (CA-1) 10 parts by mass (solid content conversion)
Amorphous resin fine particle dispersion (SA-1) 90 parts by mass (solid content conversion)
10 parts by mass of solid colorant particle dispersion (solid content conversion)
Ion-exchanged water 300 parts by mass Anionic surfactant (Dow Chemical Co., Dowfax 2A1)
4.5 parts by mass The above components are charged into a 3-liter reaction vessel equipped with a stirrer, a thermometer and a pH meter, and a 5 mol / liter aqueous solution of sodium hydroxide is added at a temperature of 25 ° C. Adjusted to 10. Next, an aqueous solution of 35 parts by mass of magnesium chloride dissolved in 35 parts by mass of ion-exchanged water is added under stirring over 10 minutes at 30 ° C., holding for 3 minutes and then temperature rise is started, and this system is maintained for 60 minutes The temperature was raised to 90.degree. C., and the particle growth reaction was continued while maintaining 90.degree.

  In this state, the particle size of the associated particles is measured with "Multisizer 3 (manufactured by Beckman Coulter)", and 150 parts by mass of sodium chloride when the volume-based median diameter (D50) reaches 6.0 μm. The particle growth is stopped by adding an aqueous solution in which 600 parts by mass of ion-exchanged water is added, and the solution is heated and stirred at a liquid temperature of 95.degree. Particle fusion was allowed to proceed to an average circularity of 0.955 as measured by. Thereafter, the solution temperature was cooled to 30 ° C., hydrochloric acid was added to adjust the pH to 4.0, and the stirring was stopped.

  The cooled slurry was passed through a nylon mesh having a pore size of 20 μm to remove coarse powder, nitric acid was added to the toner slurry having passed the mesh to adjust to pH 6.0, and vacuum filtration was performed using an aspirator. The toner remaining on the filter paper is broken up by hand as much as possible, charged into ion exchange water of 10 times the amount of toner at a temperature of 30 ° C., stirred and mixed for 30 minutes, filtered again by vacuum with an aspirator, and the conductivity of the filtrate Was measured. This procedure was repeated until the electric conductivity of the filtrate became 10 μS / cm or less to obtain a parent toner. The base toner was finely crushed by a wet dry type granulator (Comil) and vacuum dried in an oven at 35 ° C. for 36 hours to obtain toner base particles 1. The particle size of the toner base particles was 6.2 μm.

<Production of Toner Base Particles 2>
The ingredients charged in a 3 liter reaction vessel are
Crystalline resin fine particle dispersion (CA-1) 10 parts by mass (solid content conversion)
Amorphous resin fine particle dispersion (AA-1) 80 parts by mass (solid content conversion)
Releasing agent fine particle dispersion 10 parts by mass (solid content conversion)
10 parts by mass of solid colorant particle dispersion (solid content conversion)
Ion-exchanged water 300 parts by mass Anionic surfactant (Dow Chemical Co., Dowfax 2A1)
Toner base particles 2 were produced in the same manner as the toner base particles 1 except that the amount was changed to 4.5 parts by mass.

[Preparation of Toner]
<Production of Toner 1>
1 part by mass of the silica particles 1 as the first silica particles and 0.5 parts by mass of the silica particles 12 as the second silica particles are added to 100 parts by mass of the toner base particles 1 using a Henschel mixer The mixture was externally added to the toner base particles by mixing for 15 minutes at a peripheral speed of 30 m / s in blade tip peripheral speed. Thereafter, Toner 1 was obtained by sieving with a vibrating sieve having an opening of 45 μm.

<Production of Toners 2 to 13>
Toners 2 to 13 were produced in the same manner as the toner 1 except that the toner base particles and the first silica particles shown in Table II were used.

[Manufacturing of developer]
The toner 1 to 13 produced as described above was prepared using a ferrite carrier having a volume average particle diameter of 30 μm coated with a copolymer resin of cyclohexyl methacrylate and methyl methacrylate (monomer mass ratio = 1: 1), and the toner concentration was 6 mass It mixed so that it became%, the developers 1-13 were manufactured, and the following evaluation was performed. The mixer was mixed for 30 minutes using a V-type mixer.

[Evaluation]
For image output, bizhub PRESS C 1070 (manufactured by Konica Minolta Co., Ltd.) was used. The toner and the developer adjusted as described above were respectively filled in a toner cartridge and a developing device to make an image forming apparatus for evaluation.

<Image quality evaluation>
The following image quality evaluation was performed in each of a high temperature and high humidity environment (temperature 30 ° C., humidity 80% RH) and a low temperature and low humidity environment (temperature 10 ° C. and humidity 20% RH). The evaluation results are shown in Table III below.

(1) Visual Evaluation A half-tone image with a reflection density of 0.50 (hereinafter referred to as “initial image”) is printed on the first sheet using A4 size plain paper as an image support, and then the printing rate is 5%. After printing 10,000 sheets of the image of (1) in the one-sheet intermittent mode and then printing 100 sheets of an image having a printing rate of 40%, a halftone image (hereinafter referred to as "high coverage image") is output as in the initial stage. Thereafter, an image with a printing rate of 5% was printed in a sheet intermittent mode with 290,000 sheets, and then a halftone image (hereinafter referred to as "300,000 sheets after image") was output as in the initial stage.

The “initial image”, “high coverage image” and “300,000 sheets after image” obtained above were visually evaluated for white spots due to toner spillage and photoreceptor filming.
Here, the number of occurrence locations of toner spill and the number of occurrence locations of white spots were observed by observing the entire surface of the evaluation image, and counted those having sizes that could be visually detected from a position 10 cm away from the paper surface.

The visual evaluation of white spots due to toner spillage and filming was evaluated according to the following evaluation criteria, and ◎, 及 び, and 合格 were regarded as having no problem in practical use.
:: No occurrence of white spots due to toner spill and filming ○: The total number of occurrence places of white spots due to toner spill and filming is one point Δ: The total number of occurrence places of white spots due to toner spill and filming are 2 Location or 3 locations x: The total number of occurrence locations of white spots due to toner spill and filming is 4 or more

(2) Halftone Unevenness Evaluation Also, for each of the "initial image" and the "300,000 sheets after image" obtained above, the reflection density at 20 locations was measured, and the difference between the maximum value and the minimum value was measured. . When the difference between the maximum value and the minimum value exceeds 0.05, a problem in practical use arises, and it was judged as a defect of density unevenness (halftone unevenness). Specifically, uneven density was evaluated according to the following criteria, and ◎ or を was accepted.
Moreover, the measurement of the reflection density mentioned above was performed using reflection densitometer "RD-919" (made by Macbeth).

:: difference in reflection density in image is 0.02 or less ○: difference in reflection density in image is more than 0.02 but 0.05 or less ×: difference in reflection density in image is more than 0.05

(3) Evaluation of electrostatic latent image carrier (photosensitive member): Evaluation of the amount of wear of the photosensitive layer on the surface of the photosensitive member In the above-mentioned visual evaluation, after printing of the "initial image" and the "300,000 sheets after image" The film thickness of the photosensitive layer formed on the surface of the latent electrostatic image carrier (photosensitive member) was measured, and the film thickness after printing “300,000 sheets after image” was subtracted from the film thickness after “initial image” printing The value was evaluated as the amount of wear and tear. The evaluation was carried out according to the following criteria, and when the amount of wear exceeds 4 μm, a problem in practical use occurs, so it was judged as a defect, and 、, 及 び and Δ were regarded as having no problem in practical use.
The film thickness was measured by randomly measuring ten uniform film thickness portions, and taking the average value as the film thickness of the photosensitive layer of the electrostatic latent image carrier (photosensitive member). The film thickness was measured using an eddy current film thickness tester “EDDY 560C” (manufactured by HELMUT FISCHER GmbH).

:: The amount of wear is 1 μm or less ○: The amount of wear is more than 1 μm and 2 μm or less Δ: The amount of wear is more than 2 μm and 4 μm or less

  As shown in Table III, it was found that the toner according to the present invention can perform high-quality image formation for a long time in any of a high temperature and high humidity and a low temperature and low humidity environment. On the other hand, the toner according to the comparative example was inferior for any item.

1 load unit 2 sample 3 sample height 4 main cell 5 high voltage power supply 6 resistance measuring instrument 10 resistance measuring device

Claims (6)

A toner for developing an electrostatic charge image comprising toner base particles having an external additive on the surface, comprising:
At least silica particles are contained as the external additive,
The toner for developing an electrostatic charge image, wherein the silica particles contain a sulfur element.   The toner for developing an electrostatic charge image according to claim 1, wherein among the silica particles, a silica host particle contains a sulfur element.   The toner according to claim 1 or 2, wherein a content of sulfur element contained in the silica particles is in a range of 20 to 50000 mass ppm.   The toner according to any one of claims 1 to 3, wherein the silica particles contain a sodium element. As the external additive, in addition to the silica particles, the second silica particles are contained,
The toner for electrostatic image development according to any one of claims 1 to 4, wherein the second silica particles are surface-modified with silicone oil. The toner base particles contain a binder resin,
The styrene-acrylic resin contained in the binder resin is in the range of 50 to 100% by mass with respect to the total amount of the binder resin. The toner for developing an electrostatic charge image according to one aspect.

Images