JP2018120166A - Toner for electrostatic charge image development and method for manufacturing toner for electrostatic charge image development - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner for electrostatic charge image development that is excellent in heat-resistant storage property and excellent in low-temperature stability even when stored for a long period at high temperature or room temperature, and a method for manufacturing the same.SOLUTION: A toner includes a toner base particle containing a crystalline resin, an amorphous resin, and a mold release agent. In a DSC curve of the toner measured by a differential scanning calorimeter, when the glass transition temperature of the toner is Tg, the endothermic quantity based on an endothermic peak derived from the crystalline resin is ΔH(J/g), and the endothermic quantity of an endothermic peak based on enthalpy relaxation derived from the amorphous resin is ΔH(J/g), when the toner is stored in a first storage condition [Tg+10°C, humidity 50%RH, 24 hours], the formula (1) is satisfied, and when the toner is stored in a second storage condition [Tg-10°C, humidity 50%RH, 500 hours], the formula (2) is satisfied. (1) ΔH(after storage)-ΔH(before storage)≤1.0(J/g); (2) ΔH(after storage)-ΔH(before storage)≤1.0(J/g).SELECTED DRAWING: None

Description

  The present invention relates to an electrostatic charge image developing toner and a method for producing an electrostatic charge image developing toner, and in particular, an electrostatic charge image development excellent in heat-resistant storage stability and excellent in low-temperature fixability even when stored at high temperature or room temperature for a long time. The present invention relates to a toner for producing a toner and a method for producing a toner for developing an electrostatic image.

In recent years, in an electrophotographic image forming apparatus, an electrostatic image developing toner (hereinafter referred to as a toner for developing an electrostatic image) that is thermally fixed at a lower temperature in order to further save energy for the purpose of increasing the printing speed and reducing the environmental load. Simply called “toner”). In such toner, it is necessary to lower the melting temperature and melt viscosity of the binder resin, and a toner having improved low-temperature fixability by adding a crystalline resin such as a crystalline polyester resin has been proposed. (For example, refer to Patent Document 1).
However, in a toner containing a crystalline resin, the crystalline resin is compatible with the amorphous resin when heated to a temperature higher than the melting point of the crystalline resin during the production of the toner. After being shipped as a product in this state, when stored at a high temperature, crystallization of the crystalline resin that is compatible in the toner proceeds, and the low-temperature fixability deteriorates. there were.

Heat treatment is known as a means for suppressing deterioration in low-temperature fixing performance due to high-temperature storage. Recrystallization of the compatible crystalline resin proceeds by heat treatment for a long time below the softening temperature of the toner. As a result, it has been reported that deterioration of low-temperature fixability can be suppressed when the toner is stored at a high temperature (see, for example, Patent Document 2).
However, when the toner is stored at room temperature, the low-temperature fixability may be deteriorated. From this point of view, there remains room for studying toner performance even when the toner is stored at high temperature or room temperature.

JP 2001-222138 A JP 2012-42508 A

  The present invention has been made in view of the above-mentioned problems and circumstances, and the solution is to have excellent heat-resistant storage properties, and electrostatic charge image development that has excellent low-temperature fixability even when stored at high temperature or room temperature for a long period of time. And a method for producing an electrostatic charge image developing toner.

The present invention is to solve the above problems, in the process to consider the cause etc. of the problems, defines the difference between [Delta] H _A corresponding to the difference and enthalpy relaxation of [Delta] H _C corresponding to the long-term storage before and after crystallization of the toner It was found that by being within the range, the heat storage stability was excellent, and deterioration of the low-temperature fixability could be suppressed even when the toner was stored at a high temperature or room temperature for a long period of time.
That is, the said subject which concerns on this invention is solved by the following means.
1. An electrostatic charge image developing toner (hereinafter, also referred to as “toner”) including toner base particles containing at least a crystalline resin, an amorphous resin, and a release agent.
In the DSC curve of the toner measured by a differential scanning calorimeter,
The glass transition temperature of the toner is Tg,
When the endothermic amount based on the endothermic peak derived from the crystalline resin is ΔH _C (J / g), and the endothermic amount based on the enthalpy relaxation derived from the amorphous resin is ΔH _A (J / g),
When the toner is stored under the first storage condition [Tg + 10 ° C./humidity 50% RH / 24 hours], the following formula (1) is satisfied, and
An electrostatic charge image developing toner satisfying the following formula (2) when the toner is stored under a second storage condition [Tg-10 ° C./humidity 50% RH / 500 hours].
ΔH _C (after storage) −ΔH _C (before storage) ≦ 1.0 (J / g) Formula (1)
[Delta] H _A (after storage) - [Delta] H _A (before storage) ≦ 1.0 (J / g) (2)

  2. 2. The electrostatic charge image developing toner according to item 1, wherein the crystalline resin has a melting point Tm in a range of 70 to 80 ° C.

  3. 3. The toner for developing an electrostatic charge image according to item 1 or 2, wherein the content of the crystalline resin is in the range of 5 to 15% by mass with respect to the total resin amount in the toner. .

4). An electrostatic charge image developing toner manufacturing method for manufacturing the electrostatic charge image developing toner according to any one of Items 1 to 3,
The toner is produced through the following first to third steps using a dispersion liquid containing toner base particles containing at least a crystalline resin, an amorphous resin and a release agent, and an aqueous solvent. A method for producing a toner for developing an electrostatic charge image.
1st process: The process which cools the said dispersion liquid heated to the temperature more than melting | fusing point Tm of the said crystalline resin to the temperature below Tg of a toner with the cooling rate of 1 degree-C / min or more 2nd process: Said 1st After the step, the step of maintaining the temperature of the dispersion at a temperature of T1 (° C.) satisfying the following formula for 1 hour or more Tg + 5 ° C. ≦ T1 ≦ Tm−5 ° C. of crystalline resin
Third step: After the second step, the temperature of the dispersion is maintained at a temperature of T2 (° C.) satisfying the following formula for 1 hour or more. Tg−20 ° C. ≦ T2 <Tg

5. In the third step,
5. The method for producing a toner for developing an electrostatic charge image according to item 4, wherein the heat treatment is performed at a temperature (condition) of T2 (° C.) satisfying the following formula.
Tg-15 ° C ≦ T2 ≦ Tg-10 ° C

By the above-mentioned means of the present invention, it is possible to provide a toner for developing an electrostatic charge image and a method for producing a toner for developing an electrostatic charge image that are excellent in heat-resistant storage properties and excellent in low-temperature fixability even when stored at a high temperature or room temperature for a long time. it can.
The expression mechanism or action mechanism of the effect of the present invention is not clear, but is presumed as follows.
The deterioration of the low-temperature fixing performance due to high-temperature storage of the toner is due to the progress of crystallization of the crystalline resin during storage. As the amount of crystals in the toner increases, the amount of heat energy that melts the toner also increases and the fixing temperature increases, so the low-temperature fixability is considered to deteriorate. The endothermic amount based on the endothermic peak (melting peak) obtained by the differential scanning calorimetry of the toner is considered to correspond to the amount of crystals in the toner, and is expressed as “ΔH _C (J / g)” in the present invention. Accordingly, as the difference of [Delta] H _C corresponding to the long-term storage before and after the crystal amount of the toner is small, worsening the width of the low-temperature fixing property is reduced.
On the other hand, the deterioration of the low-temperature fixing performance due to storage of the toner at room temperature is due to the progress of relaxation of the enthalpy of the amorphous resin during storage. The amorphous resin is in a thermodynamically stable equilibrium state at a temperature higher than the glass transition temperature (hereinafter also referred to as Tg). Cooling from this state results in a thermodynamically unstable non-equilibrium state with a higher deposition or excess enthalpy than the equilibrium state at temperatures below Tg. This is because the volume shrinkage cannot catch up with the temperature under a temperature lower than Tg. At this time, the faster the cooling, the more the volume shrinkage cannot catch up, and the excess enthalpy increases. When stored at a temperature lower than Tg for a long time, this excess enthalpy decreases with time toward a thermodynamically stable equilibrium state. This phenomenon is called “enthalpy relaxation”. In the present invention, the difference between the enthalpy amounts before and after the occurrence of enthalpy relaxation is defined as “enthalpy relaxation amount”.
In a cooling process in toner production by a general emulsion aggregation method, it is necessary to rapidly cool the peripheral temperature range of the crystallization temperature of the crystalline substance in order to suppress the deformation of the toner base particles due to the crystalline substance. As a result, the toner base particles often have an excess enthalpy.
The amount of enthalpy relaxation can be observed by differential scanning calorimetry, and is expressed as “ΔH _A (J / g)” in the present invention. Higher enthalpy relaxation amount [Delta] H _A in the toner is increased, the fixing temperature because it eliminates the enthalpy relaxation resin thermal energy amount increases to melt becomes too high, the low temperature fixability are deteriorated considered It is done. Accordingly, as the difference of [Delta] H _A corresponding to the enthalpy relaxation amount before and after long-term storage of the toner is small, worsening the width of the low-temperature fixing property is reduced.
Therefore, by keeping the difference [Delta] H _A corresponding to the difference and enthalpy relaxation of [Delta] H _C corresponding to the long-term storage before and after the crystal amount of the toner within the prescribed value, the low-temperature fixing even toner is exposed to a high temperature or room temperature Sexual deterioration can be suppressed.

In general, crystallization of a crystalline resin proceeds at a temperature higher than the Tg of the crystalline resin and lower than the melting point of the crystalline resin. However, when there are many amorphous resins as the main binder around the crystalline resin, the crystalline resin alone cannot move. For this reason, it is considered that the crystallization of the crystalline resin proceeds at Tg or more of the toner particles including the amorphous resin.
Therefore, first, the first condition was set as a condition for sufficient crystallization. The difference in the amount of crystals in the toner before and after storage under this condition is ΔH _C (after storage) −ΔH _C (before storage), and the smaller this value, the less the crystallization proceeds during storage. That is, it is possible to suppress the deterioration of the low temperature fixability derived from the crystalline resin when the toner is stored at a high temperature.
On the other hand, the enthalpy relaxation of the amorphous resin proceeds at a temperature lower than Tg. Therefore, the second condition is set as a condition for sufficiently promoting enthalpy relaxation. Difference in enthalpy relaxation of the longitudinal and stored at this condition the toner is [Delta] H A _(after storage) - [Delta] H A _(before storage), means enthalpy relaxation can hardly proceeds during storage smaller the value . That is, it is possible to suppress the deterioration of the low-temperature fixability derived from the amorphous resin when the toner is stored at room temperature. Note that enthalpy relaxation does not proceed under the first condition, and crystallization does not proceed under the second condition. Therefore, in the first condition [Delta] H _C only, in the second condition is defined only [Delta] H _A.

The figure which shows the measuring method of endothermic quantity (DELTA) _HC based on the endothermic peak originating in the crystalline resin of a toner. The figure which shows the measuring method of endothermic quantity (DELTA) _HA of the endothermic peak based on the enthalpy relaxation originating in the amorphous resin of a toner. The figure which shows the measuring method of the glass transition temperature Tg of a toner

The electrostatic image developing toner of the present invention is an electrostatic image developing toner containing toner base particles containing at least a crystalline resin, an amorphous resin and a release agent, and is measured by a differential scanning calorimeter. In the DSC curve of the toner, the glass transition temperature of the toner is Tg, the endothermic amount based on the endothermic peak derived from the crystalline resin is ΔH _C (J / g), and it is based on the enthalpy relaxation derived from the amorphous resin. When the endothermic amount of the endothermic peak is ΔH _A (J / g), when the toner is stored under the first storage condition, the above formula (1) is satisfied and the second storage condition is satisfied. When the toner is stored in (3), the above formula (2) is satisfied. This feature is a technical feature common to or corresponding to the claimed invention.
As an embodiment of the present invention, the melting point Tm of the crystalline resin is preferably in the range of 70 to 80 ° C. from the viewpoint of low temperature fixability and heat resistance.
In addition, the content of the crystalline resin in the range of 5 to 15% by mass with respect to the total resin amount in the toner is low temperature fixability, heat resistance due to toner manufacturability and manufacturability. This is preferable.

The method for producing a toner for developing an electrostatic charge image according to the present invention uses a dispersion liquid containing toner base particles containing at least a crystalline resin, an amorphous resin and a release agent, and an aqueous solvent. The toner is manufactured through a third step.
1st process: The process which cools the said dispersion liquid heated to the temperature more than melting | fusing point Tm of the said crystalline resin to the temperature below Tg of a toner with the cooling rate of 1 degree-C / min or more 2nd process: Said 1st After the step, the step of maintaining the temperature of the dispersion at a temperature of T1 (° C.) satisfying the following formula for 1 hour or more Tg + 5 ° C. ≦ T1 ≦ Tm−5 ° C. of crystalline resin
Third step: After the second step, the temperature of the dispersion is maintained at a temperature of T2 (° C.) satisfying the following formula for 1 hour or more. Tg−20 ° C. ≦ T2 <Tg

  By cooling under the conditions in the first step, it is possible to prevent the toner from being deformed due to the exposure of the release agent to the toner surface. By performing the second step, the crystalline resin is crystallized. Progress is promoted. Also. By performing the third step, the progress of enthalpy relaxation of the amorphous resin is promoted.

In the third step, it is preferable that the heat treatment is performed at a temperature (condition) of T2 (° C.) that satisfies the following formula in that the enthalpy relaxation can proceed more in a shorter time.
Tg-15 ° C ≦ T2 ≦ Tg-10 ° C

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In addition, in this application, "-" is used in the meaning which includes the numerical value described before and behind that as a lower limit and an upper limit.

[Toner for electrostatic image development]
The electrostatic image developing toner of the present invention includes toner base particles composed of at least a binder resin containing a crystalline resin and an amorphous resin, and a release agent.
Further, in the DSC curve of the toner measured by a differential scanning calorimeter, the glass transition temperature of the toner is defined as Tg, and the endothermic amount based on the endothermic peak derived from the crystalline resin is defined as ΔH _C (J / g). The toner is stored under the first storage condition [Tg + 10 ° C./humidity 50% RH / 24 hours] where ΔH _A (J / g) is the endothermic peak based on the enthalpy relaxation derived from the crystalline resin. In the case where the toner is stored under the second storage condition [Tg-10 ° C./humidity 50% RH / 500 hours], the following formula (2) is satisfied. It is characterized by satisfying.
ΔH _C (after storage) −ΔH _C (before storage) ≦ 1.0 (J / g) Formula (1)
[Delta] H _A (after storage) - [Delta] H _A (before storage) ≦ 1.0 (J / g) (2)

  In the present invention, toner base particles added with an external additive are referred to as toner particles, and an aggregate of toner particles is referred to as toner. The toner base particles can be used as toner particles as they are, but in the present invention, toner base particles added with an external additive are used as toner particles.

[ΔH _C, ΔH _A, method of measuring Tg]
For the differential scanning calorimetry of the toner, “Diamond DSC” (manufactured by Perkin Elmer) was used, and the temperature was raised from 0 ° C. to 100 ° C. at a raising / lowering speed of 10 ° C./min, and kept at the same temperature at 100 ° C. for 1 minute. Cooling process, cooling from 100 ° C. to 0 ° C. at a cooling rate of 10 ° C./min, and isothermal holding at 0 ° C. for 1 minute, and second time of raising the temperature from 0 ° C. to 100 ° C. at a lifting rate of 10 ° C./min The measurement is performed under the measurement conditions (temperature increase / cooling conditions) through the temperature increase process in this order. As a measurement procedure, 5.0 mg of toner is sealed in an aluminum pan and set in a sample holder of “Diamond DSC”. The reference used an empty aluminum pan.
ΔH _C (before storage), ΔH _A (before storage), and Tg of the toner are calculated based on the toner base particles produced in the liquid at a theoretical Tg of the toner amorphous resin particles of −20 ° C. or lower. Dry and measure within 24 hours at the same temperature after drying.
ΔH _C (after storage) and ΔH _A (after storage) are the temperatures at which the toner is stored at the temperature of Tg−20 ° C. or lower after being dried under the first or second storage conditions, and the temperature is kept as it is after drying. It shall be measured within 24 hours.

(Method of measuring the ΔH _C)
In the DSC curve obtained at the first temperature increase in the differential scanning calorimetry of the above toner, the peak area of the endothermic peak (melting peak) derived from the crystal is calculated using the analysis software attached to the diamond DSC. The endothermic amount (heat of fusion) (ΔH _C ) was determined. The endothermic peak area of the crystal is surrounded by an endothermic peak and P1, P2 with a tangent line drawn from the intersection P1 with the base line on the high temperature side of the peak toward the end point of the endothermic peak, with the contact point being P2. It is an area. A schematic diagram is shown in FIG.

(Method of measuring the ΔH _A)
In the DSC curve obtained at the first temperature increase in the differential scanning calorimetry of the above toner, the peak area of the endothermic peak appearing in the vicinity of Tg derived from amorphous is calculated using the attached analysis software, and the amorphous absorption The amount of heat (enthalpy relaxation amount) (ΔH _A ) was determined. The endothermic peak area of the amorphous resin is such that the endothermic peak curve is drawn from the baseline start point P3 on the higher temperature side than the endothermic peak toward the endothermic peak start point, the contact point is P4, the endothermic peak and P3, P4. It is the area surrounded by. FIG. 2 shows a schematic diagram.

(Measurement method of Tg)
In the above-mentioned DSC curve obtained at the first temperature increase by the differential scanning calorimeter, the baseline A immediately before the endothermic peak derived from enthalpy relaxation and the baseline B immediately after the endothermic peak appear are drawn horizontally. The intersection C between the midpoint line of the baselines A and B and the DSC curve is defined as the glass transition temperature Tg of the toner. A schematic diagram is shown in FIG.

[Binder resin]
The binder resin constituting the toner base particles according to the present invention includes at least a crystalline resin and an amorphous resin. In the present specification, “the binder resin includes a crystalline resin” may be an embodiment in which the binder resin includes the crystalline resin itself, or a crystalline polyester polymerization segment in the hybrid crystalline polyester resin described later. Thus, the aspect containing the segment contained in other resin may be sufficient. In the present specification, “the binder resin includes an amorphous resin” may be an embodiment in which the binder resin includes the amorphous resin itself, or in the hybrid crystalline polyester resin described later. The aspect containing the segment contained in other resin like an amorphous resin segment may be sufficient.

[Crystalline resin]
The crystalline resin refers to a resin having a clear endothermic peak rather than a stepwise endothermic change in the toner DSC curve. Specifically, the clear endothermic peak means a peak in which the half-value width of the endothermic peak is within 15 ° C. when measured at a heating rate of 10 ° C./min in the DSC curve.
The content of the crystalline resin is preferably 5 to 15% by mass, and more preferably 7 to 13% by mass with respect to the total resin amount in the toner. When it is in the range of 5 to 15% by mass, a sufficient plasticizing effect is obtained and the low-temperature fixability is excellent. Further, thermal stability as a toner and stability against physical stress are also improved.

The melting point Tm of the crystalline resin is preferably in the range of 70 to 80 ° C. from the viewpoint of coexistence of fixability and thermal stability.
The melting point (Tm) of the crystalline resin can be measured by differential scanning calorimetry. Specifically, a crystalline resin sample is enclosed in an aluminum pan, set in a sample holder of “Diamond DSC” (Perkin Elmer), and raised from 0 ° C. to 100 ° C. at an elevation rate of 10 ° C./min. The temperature at the peak top of the endothermic peak in the measurement curve obtained when heated is defined as the melting point (Tm).

  From the viewpoint of low temperature fixability and gloss stability, the weight average molecular weight (Mw) of the crystalline resin is in the range of 5000 to 50000, and the number average molecular weight (Mn) is in the range of 2000 to 12500. preferable.

The weight average molecular weight (Mw) and the number average molecular weight (Mn) can be determined from the molecular weight distribution measured by gel permeation chromatography (GPC) as follows.
The sample was added to tetrahydrofuran (THF) so as to have a concentration of 1 mg / mL, and after 5 minutes of dispersion treatment using an ultrasonic disperser at room temperature, the sample solution was treated with a membrane filter having a pore size of 0.2 μm. Prepare. Using a GPC apparatus HLC-8120GPC (manufactured by Tosoh Corporation) and a column TSKguardcolumn + TSKgel SuperHZM-M (manufactured by Tosoh Corporation), while maintaining the column temperature at 40 ° C., tetrahydrofuran is flowed at a flow rate of 0.2 mL / min. 10 μL of the prepared sample solution is injected into the GPC apparatus together with the carrier solvent, the sample is detected using a refractive index detector (RI detector), and a calibration curve measured using monodisperse polystyrene standard particles is used. Calculate the molecular weight distribution of the sample. Ten polystyrenes are used for calibration curve measurement.

As crystalline resins, crystalline polyester resins, crystalline polyolefin resins, crystalline polydiene resins, crystalline polyamide resins, crystalline polyurethane resins, crystalline polyacetal resins, crystalline polyethylene terephthalate resins, crystalline polybutylene terephthalate resins, crystals Examples thereof include a crystalline polyphenylene sulfide resin, a crystalline polyether ether ketone resin, and a crystalline polytetrafluoroethylene resin.
Among these, a crystalline polyester resin is preferable. This is because the crystalline polyester resin melts at the time of heat fixing and acts as a plasticizer for the amorphous resin, so that the low temperature fixability can be improved.

  The crystalline polyester resin can be obtained, for example, by a known synthesis method by a dehydration condensation reaction between a polyvalent carboxylic acid and a polyhydric alcohol. One or more kinds of the crystalline polyester resin may be used.

  The polyvalent carboxylic acid for forming the crystalline polyester resin is a compound containing two or more carboxy groups in one molecule.

  Examples of the polyvalent carboxylic acids include saturated aliphatic dicarboxylic acids such as succinic acid, sebacic acid and dodecanedioic acid; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; aromatics such as phthalic acid, isophthalic acid and terephthalic acid A dicarboxylic acid; a trivalent or higher polyvalent carboxylic acid such as trimellitic acid and pyromellitic acid; an acid anhydride thereof; and an alkyl ester having 1 to 3 carbon atoms thereof. The polyvalent carboxylic acid is preferably an aliphatic dicarboxylic acid.

  The polyhydric alcohol for forming the crystalline polyester resin is a compound containing two or more hydroxy groups in one molecule.

  Examples of the polyhydric alcohol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7 -Aliphatic diols such as heptanediol, 1,8-octanediol, neopentylglycol, 1,4-butenediol; and trihydric or higher alcohols such as glycerin, pentaerythritol, trimethylolpropane, and sorbitol. The polyhydric alcohol is preferably an aliphatic diol.

  As the molecular weight of the crystalline polyester resin, the number average molecular weight is preferably in the range of 8500 to 12500, and more preferably in the range of 9000 to 11000.

The monomer constituting the crystalline polyester resin preferably contains 50% by mass or more of linear aliphatic monomer, and more preferably contains 80% by mass or more.
When an aromatic monomer is used, the crystalline polyester resin often has a high melting point, and when a branched aliphatic monomer is used, the crystallinity is often low. It is preferable to use a group monomer. Further, by containing 50% by mass or more of the linear aliphatic monomer, the crystallinity can be maintained in the toner. It becomes possible to maintain sufficient crystallinity by setting it as 80 mass% or more.
In addition, a linear aliphatic monomer means a linear aliphatic polyhydric carboxylic acid, a linear aliphatic polyhydric alcohol, and a linear aliphatic hydroxycarboxylic acid.

The crystalline polyester resin is preferably a hybrid crystalline polyester resin in which a crystalline polyester resin unit and a resin unit other than the polyester resin are chemically bonded.
The crystalline polyester resin unit indicates a part derived from a crystalline polyester resin, and the resin unit other than the polyester resin indicates a part derived from a resin other than the polyester resin. Examples of the resin other than the polyester resin include vinyl resins such as styrene-acrylic resins, urethane resins, and urea resins. As the resin unit other than the polyester resin, one type may be used alone, or two or more types may be used in combination.
In the hybrid crystalline polyester resin, the resin portion other than the polyester resin such as styrene-acrylic resin is highly compatible with the amorphous resin, and the crystalline polyester resin can be uniformly dispersed in the toner base particles. Further, when the toner base particles have a core / shell structure described later and the shell layer contains a hybrid crystalline polyester resin, the resin portion other than the polyester resin such as a styrene-acrylic resin contains an amorphous resin. It tends to agglomerate on the surface of the core particle and easily cover the entire surface of the core particle.

  The styrene-acrylic resin is a polymer of a styrene monomer and a (meth) acrylic acid monomer.

  Examples of the styrene monomer include styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, p-methoxy styrene, p-phenyl styrene, p-chloro styrene, p-ethyl styrene, p- n-butyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, 2,4 -Dimethyl styrene, 3, 4- dichloro styrene, these derivatives, etc. are mentioned. One of these can be used alone or in combination of two or more.

  Examples of the (meth) acrylic acid monomer include acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, and methyl methacrylate. , Ethyl methacrylate, butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, ethyl 6-hydroxyacrylate, propyl γ-aminoacrylate, stearyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, 2 -Hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl Meth) acrylate, 4-hydroxybutyl (meth) acrylate, polyethylene glycol mono (meth) acrylate. One of these can be used alone or in combination of two or more.

  In addition to the styrene monomer and the (meth) acrylic acid monomer, other monomers can also be used. Examples of other monomers that can be used include maleic acid, itaconic acid, cinnamic acid, fumaric acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester, and the like.

  The styrene-acrylic resin is prepared by adding an arbitrary polymerization initiator such as peroxide, persulfide, azo compound or the like to the above-mentioned monomer polymerization, bulk polymerization, solution polymerization, emulsion polymerization, It can be obtained by polymerization by a known polymerization method such as an emulsion method, suspension polymerization method, dispersion polymerization method or the like. For the purpose of adjusting the molecular weight at the time of polymerization, a commonly used chain transfer agent such as an alkyl mercaptan or a mercapto fatty acid ester can be used.

  The content of the styrene-acrylic resin segment in the hybrid crystalline polyester resin is preferably in the range of 1 to 30% by mass because the plasticity of the toner particles can be easily controlled.

The hybrid crystalline polyester resin can be obtained by reacting a crystalline polyester resin and a styrene-acrylic resin, which are separately prepared, and chemically bonding them.
From the viewpoint of facilitating bonding, it is preferable to incorporate a substituent capable of reacting with both the crystalline polyester resin and the styrene-acrylic resin into the crystalline polyester resin or the styrene-acrylic resin. For example, when producing styrene-acrylic resin, it can react with carboxy group (COOH) or hydroxy group (OH) of crystalline polyester resin together with styrene monomer and (meth) acrylic acid monomer as raw materials And a compound having a substituent capable of reacting with the styrene-acrylic resin is added. Thereby, the styrene-acrylic resin which has a substituent which can react with the carboxy group (COOH) or hydroxy group (OH) in crystalline polyester resin can be obtained.

  In addition, the hybrid crystalline polyester resin performs a polymerization reaction to produce a styrene-acrylic resin in the presence of a prepared crystalline polyester resin, or a crystalline polyester resin in the presence of a prepared styrene-acrylic resin. It can also be obtained by performing a polymerization reaction. In any case, a compound having a substituent capable of reacting with both the non-crystalline polyester resin and the styrene-acrylic resin as described above may be added during the polymerization reaction.

  The number average molecular weight (Mn) of the hybrid crystalline polyester resin is more preferably in the range of 2000 to 10,000 from the viewpoint of fixability.

[Amorphous resin]
An amorphous resin refers to a resin having an amorphous characteristic that has a glass transition temperature (Tg) in an endothermic curve obtained by DSC, but does not have the above-described clear endothermic peak at the time of temperature rise.

The amorphous resin is used as a binder resin together with the crystalline resin, and constitutes toner base particles. One or more amorphous resins may be used. The amorphous resin may be a vinyl resin, or may be a urethane resin, a urea resin, an amorphous polyester resin, or a modified polyester resin in which a part thereof is modified, or a combination thereof. It may be.
Amorphous resins can also be obtained, for example, by known synthesis methods. The amorphous resin is preferably a vinyl resin from the viewpoint of improving low temperature stability and high temperature storage stability.

(Amorphous vinyl resin)
The amorphous vinyl resin is not particularly limited as long as it is an amorphous vinyl resin obtained by polymerizing a vinyl compound, and examples thereof include acrylic ester resins, styrene-acrylic ester resins, and ethylene-vinyl acetate resins. These may be used individually by 1 type and may be used in combination of 2 or more type. Of these, styrene-acrylic ester resin (styrene-acrylic resin) is preferable in consideration of plasticity during heat fixing.

  The weight average molecular weight (Mw) of the amorphous vinyl resin is in the range of 20000 to 150,000, and the number average molecular weight (Mn) is in the range of 5000 to 20000. It is preferable from the viewpoint of compatibility. A weight average molecular weight (Mw) and a number average molecular weight (Mn) can be measured similarly to the case of the said crystalline resin.

The glass transition temperature (Tg) of the amorphous vinyl resin is preferably in the range of 20 to 70 ° C. from the viewpoint of achieving both fixability and heat-resistant storage stability.
The glass transition temperature (Tg) can be measured according to a method (DSC method) defined in ASTM (American Society for Testing and Materials) D3418-82. For the measurement, a DSC-7 differential scanning calorimeter (manufactured by PerkinElmer), a TAC7 / DX thermal analyzer controller (manufactured by PerkinElmer) or the like can be used.

  The amorphous vinyl resin may be a polymer only of a monomer, or may be a copolymer of the monomer and another monomer. As other monomers, styrene monomers such as styrene and styrene derivatives can be used.

(Amorphous polyester resin)
Amorphous polyester resin is a non-crystalline polyester among polyester resins obtained by polycondensation reaction of divalent or higher carboxylic acid (polyvalent carboxylic acid) and divalent or higher alcohol (polyhydric alcohol). Resin. When forming a toner having a core / shell structure, an amorphous polyester resin may be used as a material for the shell layer.

  As polyvalent carboxylic acid and polyhydric alcohol, the same material as the crystalline polyester resin described above can be used.

  The ratio of the polyhydric carboxylic acid to the polyhydric alcohol is such that the equivalent ratio [OH] / [COOH] of the hydroxy group of the polyhydric alcohol to the carboxy group of the polyhydric carboxylic acid is 1.5 / 1 to 1 / 1.5. Preferably, it exists in the range of 1.2 / 1-1 / 1.2, more preferably.

  The number average molecular weight (Mn) of the amorphous polyester resin is preferably in the range of 2000 to 10,000. The number average molecular weight (Mn) can be measured in the same manner as in the case of the amorphous vinyl resin.

  The glass transition temperature (Tg) of the amorphous polyester resin is preferably in the range of 20 to 70 ° C. The glass transition temperature (Tg) can be measured in the same manner as in the case of the amorphous vinyl resin.

  The amorphous polyester resin is preferably a hybrid amorphous polyester resin in which an amorphous polyester resin unit and a resin unit other than the polyester resin are chemically bonded, like the above-described crystalline polyester resin.

In the hybrid amorphous polyester resin, the resin portion other than the polyester resin such as styrene acrylic resin is highly compatible with the amorphous vinyl resin, and the amorphous polyester resin can be uniformly dispersed in the toner base particles. it can. When the toner base particles have a core-shell structure and the shell layer contains an amorphous polyester resin, the toner particles tend to aggregate on the surface of the core particles containing the amorphous vinyl resin, and the entire surface is easily covered. .
The styrene-acrylic resin can be produced in the same manner using the same material as the above hybrid crystalline polyester resin.

  The number average molecular weight (Mn) of the hybrid amorphous polyester resin is more preferably in the range of 2000 to 10,000 from the viewpoint of fixability.

  The content of the amorphous polyester resin in the toner base particles is preferably in the range of 1 to 50% by mass from the viewpoint of fixability and charging environmental stability.

[Release agent]
Examples of the release agent (wax) include hydrocarbon waxes and ester waxes. Examples of the hydrocarbon wax include low molecular weight polyethylene wax, low molecular weight polypropylene wax, Fischer-Tropsch wax, microcrystalline wax and paraffin wax. Examples of the ester wax include carnauba wax, pentaerythritol behenate, behenyl behenate and behenyl citrate. One or more release agents may be used.

  In addition to the amorphous resin, the crystalline resin, and the release agent, the toner base particles according to the present invention contain various additives such as a colorant, a charge control agent, and a surfactant as necessary. It is preferable to contain.

[Colorant]
As the colorant, a known inorganic or organic colorant used for color toners is used. Examples of the colorant include carbon black, a magnetic material, a pigment, and a dye. One or more colorants may be used.

Examples of carbon black include channel black, furnace black, acetylene black, thermal black and lamp black.
Examples of the magnetic material include ferromagnetic metals such as iron, nickel, and cobalt, alloys containing these metals, and compounds of ferromagnetic metals such as ferrite and magnetite.

  Examples of pigments include C.I. I. Pigment Red 2, 3, 5, 7, 15, 16, 48: 1, 48: 3, 53: 1, 57: 1, 81: 4, 122, 123, 139, 144, 149, 166, 177, 178, 208, 209, 222, 238, 269, C.I. I. Pigment Orange 31 and 43, C.I. I. Pigment Yellow 3, 9, 14, 17, 35, 36, 65, 74, 83, 93, 94, 98, 110, 111, 138, 139, 153, 155, 180, 181, 185, C.I. I. Pigment green 7, C.I. I. Pigment Blue 15: 3, 15: 4, 60, and phthalocyanine pigments whose central metal is zinc, titanium, magnesium, or the like.

  Examples of dyes include C.I. I. Solvent Red 1, 3, 14, 17, 17, 22, 22, 49, 51, 52, 58, 63, 87, 111, 122, 127, 128, 131, 145, 146, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 176, 179, pyrazolotriazole Azo dyes, pyrazolotriazole azomethine dyes, pyrazolone azo dyes, pyrazolone azomethine dyes, 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 and 95 are included.

[Charge control agent]
Examples of the charge control agent include nigrosine dyes, naphthenic acid or higher fatty acid metal salts, alkoxylated amines, quaternary ammonium salt compounds, azo metal complexes and salicylic acid metal salts or metal complexes thereof. One or more charge control agents may be used.

[Surfactant]
Examples of surfactants include anionic surfactants such as sulfate ester, sulfonate, and phosphate ester; cationic surfactants such as amine salt type and quaternary ammonium salt type; polyethylene glycol type And nonionic surfactants such as alkylphenol ethylene oxide adducts and polyhydric alcohols. One or more surfactants may be used.

Specific examples of the anionic surfactant include sodium dodecylbenzenesulfonate, sodium dodecylsulfate, sodium alkylnaphthalenesulfonate, and sodium dialkylsulfosuccinate.
Specific examples of the cationic surfactant include alkylbenzene dimethyl ammonium chloride, alkyl trimethyl ammonium chloride, and distearyl ammonium chloride. Examples of the nonionic surfactant include polyoxyethylene alkyl ether, glycerin fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, and polyoxyethylene fatty acid ester.

[Toner Production Method]
The toner production method of the present invention uses a dispersion liquid containing toner base particles containing at least a crystalline resin, an amorphous resin, and a release agent, and an aqueous solvent, and then undergoes the following first to third steps. The toner is manufactured.
1st process: The process which cools the said dispersion liquid heated to the temperature more than melting | fusing point Tm of the said crystalline resin to the temperature below Tg of a toner with the cooling rate of 1 degree-C / min or more 2nd process: Said 1st After the step, the step of maintaining the temperature of the dispersion at a temperature of T1 (° C.) satisfying the following formula for 1 hour or more Tg + 5 ° C. ≦ T1 ≦ Tm−5 ° C. of crystalline resin
Third step: After the second step, the temperature of the dispersion is maintained at a temperature of T2 (° C.) satisfying the following formula for 1 hour or more. Tg−20 ° C. ≦ T2 <Tg

By cooling under the conditions in the first step, it is possible to prevent the toner from being deformed due to the exposure of the crystalline substance to the surface of the toner base particles.
By performing the second step, the progress of crystallization of the crystalline resin is promoted. When the temperature is Tg + 5 ° C. or higher, the amorphous resin surrounding the crystalline resin is easy to move, so that crystallization is likely to proceed. Moreover, since it becomes difficult to melt | dissolve crystalline resin as it is below Tm-5 degreeC, crystallization will advance easily.
By performing the third step, the progress of enthalpy relaxation of the amorphous resin is promoted. Enthalpy relaxation proceeds at a temperature lower than Tg, and by setting the temperature to Tg−20 ° C. or higher, the speed at which enthalpy relaxation proceeds does not become too slow, and the productivity is high.
Further, if the second step and the third step are reversed, the effect of the third step is lost. This is because if the temperature of the enthalpy-relieved toner is raised to Tg or higher, the enthalpy relaxation is eliminated.
In addition, as described above, in the production method of the present invention, the dispersion is heat-treated, because the heat treatment in water has the following advantages over the heat treatment in the air.
-When heat treatment is performed in the air for a long time, the air is hydrophobic, so that the crystalline substance is exposed on the toner surface and may cause a decrease in heat-resistant storage stability.
-When heat treatment in the air is performed under stirring, the toner particles collide with each other, so that the toner may be broken.
・ Underwater has higher thermal conductivity than air, so enthalpy relaxation is easy to proceed and efficiency is high.

Hereinafter, the first to third steps will be described.
[First step]
In the first step, a dispersion containing toner base particles and an aqueous solvent is heated to a temperature equal to or higher than the melting point Tm of the crystalline resin, and the heated dispersion is heated at a cooling rate of 1 ° C./min. This is a step of cooling to a temperature below Tg.
The heating temperature of the dispersion is preferably not less than the melting point Tm of the crystalline resin and more preferably not less than Tm + 5 ° C. from the viewpoint of manufacturability of toner base particles (aggregation of fine particles of the binder resin). The upper limit of the heating temperature is preferably not more than the boiling point of the aqueous medium (for example, the boiling point of water).
A known heating device such as a heater can be used for heating the dispersion. The melting point Tm of the crystalline resin can be measured by the DSC described above. Further, the glass transition temperature Tg of the toner can also be measured by the DSC described above.

The cooling rate of the dispersion is preferably 1 ° C./min or more, more preferably 2 ° C./min or more, and further preferably 5 ° C./min or more from the viewpoint of suppressing the exposure of the crystalline substance to the toner base particle surface. preferable. However, if the cooling rate is too high, crystal nucleus formation during cooling is small, and the progress of crystallization is slowed. From the viewpoint of productivity, the upper limit of the cooling rate is preferably 25 ° C./min or less.
The dispersion liquid can be cooled using a known cooling device capable of realizing the above cooling rate. For example, the outer bath of the reaction vessel may be rapidly cooled, the dispersion may be passed through a heat exchanger, or ion-exchanged water cooled in the dispersion may be charged. From the viewpoint of production efficiency, it is preferable to perform cooling using a heat exchanger.

(Aqueous solvent)
The aqueous solvent refers to a medium having a water content of 50% by mass or more. Components other than water include organic solvents that dissolve in water, such as methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, and tetrahydrofuran. Of these, alcohol-based organic solvents that do not dissolve resins such as methanol, ethanol, isopropanol, and butanol are particularly preferable.

(Toner base particles)
The method for producing the toner base particles is not particularly limited. For example, the toner base particles are produced by aggregating and fusing crystalline resin fine particles and fine particles containing a release agent and an amorphous resin in an aqueous solvent.

An aggregating agent may be used to agglomerate the fine particles of the binder resin.
The aggregating agent is not particularly limited, but an aggregating agent selected from metal salts is suitable as an aggregating agent that grows particles by using a charge neutralization reaction and a crosslinking action. Examples of the metal salts include monovalent metal salts such as alkali metal salts such as sodium, potassium and lithium; divalent metal salts such as calcium, magnesium, manganese and copper; trivalent metals such as iron and aluminum. Metal salts. Specific metal salts can include sodium chloride, potassium chloride, lithium chloride, calcium chloride, magnesium chloride, zinc chloride, copper sulfate, magnesium sulfate, manganese sulfate, and the like. It is particularly preferable to use a divalent metal salt. These can be used alone or in combination of two or more.

  By adding the aggregating agent, the binder resin particles are bonded together by ionic crosslinking in an aqueous solvent, so that the presence state of the crystalline resin or the amorphous resin can be controlled more advantageously during the heat treatment. it can.

Aggregated particle growth can be substantially stopped by increasing the salt concentration in the aqueous solvent. For example, sodium chloride, polyvalent organic acid or a salt thereof, amino acid, polyphosphonic acid or a salt thereof can be used as the aggregation terminator. In addition, the aggregating action can be alleviated by changing the pH in the system. In order to adjust the pH, a sodium fumarate aqueous solution, a sodium hydroxide aqueous solution, hydrochloric acid or the like can be used. Furthermore, it is also effective to adjust the pH and use a chelating agent in combination to alleviate the crosslinking action caused by metal ions.
Examples of the chelating agent include HIDA (hydroxyethyliminodiacetic acid), HEDTA (hydroxyethylethylenediaminetriacetic acid), HEDP (hydroxyethylidene diphosphonic acid), and HIDS (3-hydroxy-2,2′-iminodisuccinic acid). included.

  The average circularity of the obtained toner base particles can be adjusted by an aging step for aging the toner base particles. In the aging step, the dispersion of the toner base particles is heated, and the toner base particles are aged until the target toner base particles having an average circularity are obtained.

The toner base particles may have a core / shell structure.
When forming toner base particles having a core-shell structure, a shell layer is formed on the surface of the core particles using the toner base particles as core particles.
Specifically, a resin particle dispersion in which the resin constituting the shell layer is dispersed in an aqueous solvent is prepared and added to the dispersion of the toner base particles obtained by the toner particle forming step or the aging step. The resin particles of the shell layer are aggregated and fused on the surface of the toner particles. As a result, a dispersion of toner base particles having a core / shell structure can be obtained. In order to more strongly aggregate and fuse the resin particles of the shell layer to the core particles, a heat treatment can be performed following the shelling step. The heat treatment may be performed until the desired toner base particles having an average circularity are obtained.

In addition, within the range where the effects of the present invention can be achieved, other toner materials other than the crystalline resin, the amorphous resin, and the release agent are dispersed in the crystalline resin fine particle dispersion, the amorphous resin fine particle dispersion, and Further, it may be added to a dispersion of fine particles of a release agent to perform aggregation and fusion reaction.
Examples of the other toner materials include the above-described colorants, charge control agents, surfactants, and the like. The other toner material may be contained in one kind or more. In the case of adding other toner materials, the above aggregation and fusion reaction is carried out by separately preparing a dispersion containing fine particles of other toner materials such as a colorant, and using this as a crystalline resin or an amorphous resin, You may carry out by mixing with the dispersion liquid containing the fine particle of a mold release agent.

  The toner base particles produced as described above may be once taken out from the dispersion and then used in the first step. However, the toner base particles may be used in the first step while being contained in the dispersion. Is preferred.

[Binder resin fine particles]
The fine particles of the binder resin can be produced by an emulsion polymerization method in which a resin monomer is added to an aqueous solvent together with a polymerization initiator, and the monomer is polymerized to obtain a dispersion of resin particles. In the emulsion polymerization method, the polymerization reaction can be performed in multiple stages. For example, when the polymerization reaction is performed in three stages, a dispersion of resin particles is prepared by the first stage polymerization, and a resin monomer and a polymerization initiator are further added to the dispersion to obtain a second stage polymerization. Polymerization. A resin monomer and a polymerization initiator are further added to the dispersion prepared by the second stage polymerization to cause the third stage polymerization. During the second and third stage polymerizations, the resin particles in the dispersion produced by the previous polymerization can be used as seeds to further polymerize the monomer newly added to the resin particles. It is possible to make the particle size of the resin particles uniform. In addition, by using different monomers in the polymerization reaction at each stage, the resin particle structure can also be a multilayer structure, and it is easy to obtain resin particles having desired characteristics.

(Polymerization initiator)
As the polymerization initiator that can be used in the polymerization reaction, known polymerization initiators can be used. For example, persulfates such as ammonium persulfate, sodium persulfate, and potassium persulfate, 2,2′-azobis (2- Aminodipropane) hydrochloride, 2,2'-azobis- (2-aminodipropane) nitrate, 4,4'-azobis-4-cyanovaleric acid, poly (tetraethylene glycol-2,2'-azobisiso) Azo compounds such as butyrate) and peroxides such as hydrogen peroxide.
The addition amount of the polymerization initiator varies depending on the target molecular weight and molecular weight distribution, but specifically, it may be in the range of 0.1 to 5.0% by mass with respect to the addition amount of the polymerizable monomer. it can.

(Chain transfer agent)
In the polymerization reaction, a chain transfer agent can be added from the viewpoint of controlling the molecular weight of the resin particles. Examples of chain transfer agents that can be used include mercaptans such as octyl mercaptan and mercaptopropionic acids such as n-octyl-3-mercaptopropionate.
Although the addition amount of a chain transfer agent changes with target molecular weights or molecular weight distribution, it can be in the range of 0.1-5.0 mass% with respect to the addition amount of a polymerizable monomer.

(Surfactant)
During the polymerization reaction, a surfactant can be added from the viewpoint of preventing aggregation of the resin fine particles in the dispersion and maintaining a good dispersion state.
Examples of the surfactant include cationic surfactants such as dodecyl ammonium bromide and dodecyl trimethyl ammonium bromide, anionic surfactants such as sodium stearate, sodium lauryl sulfate (sodium dodecyl sulfate), and sodium dodecyl benzene sulfonate. Known surfactants such as nonionic surfactants such as dodecyl polyoxyethylene ether and hexadecyl polyoxyethylene ether can be used. You may use 1 type of these individually or in combination of 2 or more types.

[Second step]
A 2nd process is a process of hold | maintaining the temperature of the said dispersion liquid to the temperature of T1 (degreeC) which satisfy | fills a following formula after the 1st process for 1 hour or more.
Tg + 5 ° C. ≦ T1 ≦ Tm−5 ° C. of crystalline resin
The temperature of T1 is more preferably Tg + 10 ° C. or higher and Tm−10 ° C. or lower.
Moreover, in order to heat the temperature of the dispersion liquid to the temperature of T1, a known heating device such as a heater can be used.
The time for maintaining the temperature at T1 is preferably 1 hour or longer, more preferably 3 hours or longer. The upper limit is not particularly limited, but the upper limit of the heat treatment time is preferably about 50 hours from the viewpoint of production efficiency.

[Third step]
A 3rd process is a process of hold | maintaining the temperature of the said dispersion liquid at the temperature of following T2 (degreeC) for 1 hour or more after a 2nd process.
Tg−20 ° C. ≦ T2 <Tg
The temperature of T2 (° C.) more preferably satisfies the following formula.
Tg-15 ° C ≦ T2 ≦ Tg-10 ° C
Here, in the enthalpy relaxation, in the temperature range lower than Tg, the higher the temperature, the faster the enthalpy relaxation proceeds (relaxation speed), but the smaller the enthalpy relaxation proceeds. On the other hand, in the temperature range below Tg, the lower the temperature, the slower the relaxation rate, but the greater the amount of enthalpy relaxation that proceeds. Therefore, an efficient temperature range in which enthalpy relaxation can be advanced more in less time is Tg-15 ° C. ≦ T2 ≦ Tg−10 ° C.

In order to set the temperature of the dispersion to the temperature T2, a known cooling device can be used. For example, the outer bath of the reaction vessel may be rapidly cooled, the dispersion may be passed through a heat exchanger, or ion-exchanged water cooled in the dispersion may be charged. From the viewpoint of production efficiency, it is preferable to perform cooling using a heat exchanger.
The time for maintaining the temperature at T2 is preferably 1 hour or longer, more preferably 10 hours or longer, and further preferably 30 hours or longer. The upper limit is not particularly limited, but the upper limit of the heat treatment time is preferably about 500 hours from the viewpoint of production efficiency.

  The toner manufacturing method according to the present exemplary embodiment may further include other steps than the first to third steps described above within a range where the effects of the present exemplary embodiment are achieved. Examples of the other steps include a step of mixing and adhering an external additive to the obtained toner base particles to obtain toner particles, and mixing the obtained toner particles with carrier particles as a two-component developer. And a step of obtaining the toner.

[Toner base particle structure]
The structure of the toner base particles of the present embodiment may be a single-layer structure of only the above-described toner base particles, or the core particles and the shell layer covering the surface of the toner base particles described above as core particles. It may be a multilayer structure such as a core / shell structure provided. 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 a transmission electron microscope (TEM) or a scanning probe microscope (SPM).

  In the case of the core-shell structure, the core particles and the shell layer can have different characteristics such as glass transition temperature, melting point, hardness, etc., and toner base particles can be designed according to the purpose. For example, a resin having a relatively high glass transition temperature (Tg) is aggregated and fused on the surface of a core particle containing a binder resin, a colorant, a release agent, etc. and having a relatively low glass transition temperature (Tg). Thus, a shell layer can be formed. As the shell layer, an amorphous polyester resin can be used as described above, and among them, a hybrid amorphous polyester resin can be preferably used.

[Melting point of toner base particles]
The toner base particles preferably have a melting point (Tm) in the range of 60 to 90 ° C, more preferably in the range of 65 to 80 ° C. If the melting point is within the above range, sufficient low-temperature fixability and heat-resistant storage stability can be achieved. Further, good heat resistance (thermal strength) of the toner can be maintained, and sufficient heat-resistant storage stability can be obtained. The melting point (Tm) can be measured in the same manner as the crystalline polyester resin.

[Particle size of toner base particles]
The volume-based median diameter of the toner base particles according to the present invention is preferably in the range of 3 to 8 μm, and more preferably in the range of 5 to 8 μm.
If the volume-based median diameter is within the above range, a high-resolution dot of 1200 dpi level can be accurately reproduced.
The volume-based median diameter can be controlled by the concentration of the aggregating agent used in the production, the amount of the organic solvent added, the fusing time, the composition of the binder resin, and the like.

The volume-based median diameter can be measured using a measuring apparatus in which a computer system equipped with data processing software Software V3.51 is connected to Multisizer 3 (manufactured by Beckman Coulter).
Specifically, 0.02 g of a sample (toner) was added to 20 mL of a surfactant solution (for the purpose of dispersing toner particles, for example, a surfactant obtained by diluting a neutral detergent containing a surfactant component 10 times with pure water. After adding the solution to the solution), the mixture is subjected to ultrasonic dispersion for 1 minute to prepare a toner dispersion. This toner dispersion is injected into a beaker containing ISOTON II (manufactured by Beckman Coulter, Inc.) in a sample stand with a pipette until the display density of the measuring apparatus becomes 8%. By using this concentration, a reproducible measurement value can be obtained.
In the measurement apparatus, the measurement particle count is 25000, the aperture diameter is 100 μm, the frequency range is calculated by dividing the range of 2 to 60 μm, which is the measurement range, into 256, and the volume integrated fraction is 50 % Particle diameter is determined as a volume-based median diameter.

[Average circularity of toner base particles]
In the toner according to the present invention, the average circularity of the toner base particles is preferably in the range of 0.930 to 1.000, and more preferably in the range of 0.950 to 0.995.
If the average circularity is within the above range, the toner base particles can be prevented from being crushed, the contamination of the frictional charge imparting member can be suppressed, and the chargeability of the toner can be stabilized. In addition, an image formed with toner has high image quality.

The average circularity can be measured as follows. A toner dispersion is prepared in the same manner as when measuring the median diameter. Using an FPIA-2100, FPIA-3000 (both manufactured by Sysmex), etc., in the HPF (high magnification imaging) mode, a toner dispersion liquid is photographed in an appropriate density range of 3000 to 10,000 HPF detections. The circularity of the toner particles is calculated by the following formula (y). The average circularity is calculated by adding the circularity of each toner particle and dividing the sum of the circularity by the number of each toner particle. If the number of HPF detections is within the appropriate concentration range, sufficient reproducibility can be obtained.
Formula (y) Circularity = (perimeter of a circle having the same projection area as the particle image) / (perimeter of the particle projection image)

[External additive]
The toner particles according to the present invention may have, for example, the toner base particles and an external additive present on the surface thereof. It is preferable that the toner particles contain an external additive from the viewpoint of controlling the fluidity and chargeability of the toner particles. The external additive may be one kind or more. Examples of the external additive include silica particles, titania particles, alumina particles, zirconia particles, zinc oxide particles, chromium oxide particles, cerium oxide particles, antimony oxide particles, tungsten oxide particles, tin oxide particles, tellurium oxide particles, oxidation Manganese particles and boron oxide particles are included.

  More preferably, the external additive includes silica particles produced by a sol-gel method. Silica particles produced by the sol-gel method have a feature that the particle size distribution is narrow, and thus are preferable from the viewpoint of suppressing variation in adhesion strength of the external additive to the toner base particles.

  The number average primary particle diameter of the silica particles is preferably in the range of 70 to 200 nm. Silica particles having a number average primary particle size in the above range are larger than other external additives. Therefore, it has a role as a spacer in the two-component developer. Therefore, it is preferable from the viewpoint of preventing other smaller external additives from being embedded in the toner base particles when the two-component developer is stirred in the developing device. Further, it is also preferable from the viewpoint of preventing fusion between the toner base particles.

  The number average primary particle diameter of the external additive can be determined by, for example, image processing of an image taken with a transmission electron microscope, and can be adjusted by classification or mixing of classified products, for example. .

  The surface of the external additive is preferably hydrophobized. A known surface treating agent is used for the hydrophobic treatment. The surface treatment agent may be one type or more, and examples thereof include silane coupling agents, silicone oils, titanate coupling agents, aluminate coupling agents, fatty acids, fatty acid metal salts, esterified products thereof, and the like. Rosin acid is included.

  Examples of the silane coupling agent include dimethyldimethoxysilane, hexamethyldisilazane (HMDS), methyltrimethoxysilane, isobutyltrimethoxysilane, and decyltrimethoxysilane. Examples of the silicone oil include cyclic compounds, linear or branched organosiloxanes, and more specifically, organosiloxane oligomers, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, tetramethyl. Cyclotetrasiloxane and tetravinyltetramethylcyclotetrasiloxane.

  Examples of the silicone oil include a highly reactive silicone oil in which a modifying group is introduced into a side chain or one end or both ends, a side chain piece end, a side chain both ends, etc., and at least the end is modified. . One or more kinds of the modifying group may be used, and examples thereof include alkoxy, carboxy, carbinol, higher fatty acid modification, phenol, epoxy, methacryl and amino.

  The addition amount of the external additive is preferably in the range of 0.1 to 10.0% by mass with respect to the whole toner particles. More preferably, it exists in the range of 1.0-3.0 mass%.

[Developer]
If the toner of the present invention is a one-component developer, it is composed of the toner particles, and if it is a two-component developer, the toner is composed of the toner particles and carrier particles. The toner particle content (toner concentration) in the two-component developer may be the same as that of a normal two-component developer, and is, for example, in the range of 4.0 to 8.0% by mass.

  The carrier particles are made of a magnetic material. Examples of the carrier particles include coated carrier particles having core material particles made of the magnetic material and a coating material layer covering the surface thereof, and fine powder of the magnetic material dispersed in the resin. Resin dispersed carrier particles. The carrier particles are preferably the coated carrier particles from the viewpoint of suppressing the adhesion of the carrier particles to the photoreceptor.

  The core particle is made of a magnetic material, for example, a material that is strongly magnetized in the direction by a magnetic field. The magnetic substance may be one kind or more, and examples thereof include metals exhibiting ferromagnetism such as iron, nickel and cobalt, alloys or compounds containing these metals, and exhibit ferromagnetism by heat treatment. Alloys.

  Examples of the metal exhibiting ferromagnetism or a compound containing the same include iron, ferrite represented by the following formula (a), and magnetite represented by the following formula (b). M in the formulas (a) and (b) represents one or more monovalent or divalent 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

  Examples of alloys or metal oxides that exhibit ferromagnetism by heat treatment include Heusler alloys such as manganese-copper-aluminum and manganese-copper-tin, and chromium dioxide.

  The core particle is preferably the ferrite. This is because the specific gravity of the coated carrier particles is smaller than the specific gravity of the metal constituting the core material particles, so that the impact force of stirring in the developing device can be further reduced.

The coating material may be one type or more.
As the coating material, a known resin used for coating the core particles of the carrier particles can be used. It is preferable that the coating material is a resin having a cycloalkyl group from the viewpoint of reducing the moisture adsorptivity of the carrier particles and increasing the adhesion of the coating layer to the core material particles.
Examples of the cycloalkyl group include a cyclohexyl group, a cyclopentyl group, a cyclopropyl group, a cyclobutyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, and a cyclodecyl group. Among these, a cyclohexyl group or a cyclopentyl group is preferable, and a cyclohexyl group is more preferable from the viewpoint of adhesion between the coating layer and the ferrite particles.

The weight average molecular weight Mw of the resin having a cycloalkyl group is, for example, 10,000 to 800,000, and more preferably 100,000 to 750000. Content of the said cycloalkyl group in the said resin exists in the range of 10-90 mass%, for example. The content of the cycloalkyl group in the resin can be determined by using a known instrumental analysis method such as Py-GC / MS or ¹ H-NMR.

  The two-component developer can be produced by mixing an appropriate amount of the toner particles and the carrier particles. Examples of the mixing device used for the mixing include a Nauter mixer, a W cone, and a V-type mixer.

  Further, the size and shape of the carrier particles can be appropriately determined within a range in which the effect of the present embodiment can be obtained. For example, the carrier particles have a volume average particle size of 15 to 100 μm. The volume average particle diameter of the carrier particles can be measured by a wet method using, for example, a laser diffraction particle size distribution analyzer “HELOS KA” (manufactured by Nippon Laser Corporation). The volume average particle size of the carrier particles is adjusted by, for example, a method of controlling the particle size of the core material particles according to the manufacturing conditions of the core material particles, classification of the carrier particles, mixing of classified products of the carrier particles, or the like. Is possible.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.
[Synthesis of crystalline resin and preparation of dispersion thereof]
<Synthesis of crystalline resin 1>
A raw material monomer of the following addition polymerization resin (styrene acrylic resin: StAc) unit and a radical polymerization initiator containing both reactive monomers were placed in a dropping funnel.
Styrene 43.5 parts by mass n-butyl acrylate 16 parts by mass Acrylic acid 3.5 parts by mass Polymerization initiator (di-t-butyl peroxide) 8 parts by mass The following polycondensation resins (crystalline polyester resins: CPEs) ) The raw material monomer of the unit was placed in a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple, and heated to 170 ° C. to dissolve.
Tetradecanedioic acid 440 parts by mass Butanediol 135 parts by mass Next, the raw material monomer of the addition polymerization resin (StAc) was added dropwise over 90 minutes with stirring, and after aging for 60 minutes, the pressure was not reduced under reduced pressure (8 kPa). The addition polymerization monomer of the reaction was removed. The amount of monomer removed at this time was very small with respect to the raw material monomer ratio of the resin.
Thereafter, 0.8 part by mass of Ti (OBu) ₄ was added as an esterification catalyst, the temperature was raised to 235 ° C., and the reaction was performed for 5 hours under normal pressure (101.3 kPa) and further for 1 hour under reduced pressure (8 kPa). went.
Next, after cooling to 200 ° C., a crystalline resin 1 was obtained by reacting under reduced pressure (20 kPa) for 1 hour. The crystalline resin 1 contained 10% by mass of a resin (StAc) unit other than CPEs based on the total amount, and was a resin in a form in which CPEs were grafted to StAc. The number average molecular weight (Mn) of the obtained crystalline resin 1 was 9500, and the melting point (Tm) was 72 ° C.

<Synthesis of crystalline resin 2>
In the synthesis example of the crystalline resin 1, the crystalline resin 2 was synthesized in the same manner except that the raw material monomer of the polycondensation resin (crystalline polyester resin: CPEs) unit was changed as follows.
Dodecanedioic acid 391 parts by mass Ethylene glycol 100 parts by mass The obtained crystalline resin 2 had a number average molecular weight (Mn) of 10,000 and a melting point (Tm) of 79 ° C.

<Synthesis of crystalline resin 3>
In the synthesis example of the crystalline resin 1, the crystalline resin 3 was synthesized in the same manner except that the raw material monomer of the polycondensation resin (crystalline polyester resin: CPEs) unit was changed as follows.
Dodecanedioic acid 391 parts by mass 1,9-nonanediol 240 parts by mass The obtained crystalline resin 3 had a number average molecular weight (Mn) of 9000 and a melting point (Tm) of 66 ° C.

<Preparation of crystalline resin particle dispersion 1>
100 parts by mass of crystalline resin 1 was dissolved in 400 parts by mass of ethyl acetate (manufactured by Kanto Chemical Co., Ltd.) and mixed with 638 parts by mass of a 0.26% by mass sodium lauryl sulfate solution prepared in advance. . While stirring the mixed solution, ultrasonic dispersion treatment was performed for 30 minutes at 300 μA V-LEVEL using an ultrasonic homogenizer US-150T (manufactured by Nippon Seiki Seisakusho). Then, using a diaphragm vacuum pump V-700 (manufactured by BUCHI) in a state heated to 40 ° C., ethyl acetate was completely removed while stirring under reduced pressure for 3 hours to obtain a crystalline polyester resin particle dispersion. (Crystalline resin particle dispersion 1) was prepared. The crystalline resin particles in the dispersion had a volume-based median diameter of 160 nm.

<Preparation of crystalline resin particle dispersions 2 and 3>
Crystalline resin fine particle dispersions 2 and 3 were prepared in the same manner as in the preparation example of the crystalline resin particle dispersion 1, except that the crystalline resins 2 and 3 were used instead of the crystalline resin 1. The volume average particle diameters of the crystalline resin particles in Dispersion 2 and Dispersion 3 were each 160 nm.

<Preparation of colorant particle dispersion>
While stirring a solution obtained by adding 90 parts by mass of sodium dodecyl sulfate to 1600 parts by mass of ion-exchanged water, 420 parts by mass of copper phthalocyanine (CI Pigment Blue 15: 3) was gradually added. A colorant particle dispersion was prepared by dispersing using a stirrer CLEARMIX (M Technique Co., Ltd., “CLEAMIX” is a registered trademark of the company). The colorant particles in the dispersion had a volume-based median diameter of 110 nm.

<Preparation of amorphous polyester resin>
The following vinyl resin monomer, a mixture of a monomer having a substituent that reacts with both the amorphous polyester resin and the vinyl resin, and a polymerization initiator were placed in a dropping funnel.
Styrene 80.0 parts by mass n-butyl acrylate 20.0 parts by mass Acrylic acid 10.0 parts by mass Di-t-butyl peroxide (polymerization initiator) 16.0 parts by mass In addition, a single amount of the following amorphous polyester resin The body was placed in a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple, and heated to 170 ° C. to dissolve.
Bisphenol A ethylene oxide 2 mol adduct 59.1 parts by mass Bisphenol A propylene oxide 2 mol adduct 281.7 parts by mass Terephthalic acid 63.9 parts by mass Succinic acid 48.4 parts by mass Mixing in a dropping funnel under stirring The liquid was dropped into a four-necked flask over 90 minutes, and after aging for 60 minutes, unreacted monomers were removed under reduced pressure (8 kPa). Thereafter, 0.4 parts by mass of Ti (OBu) ₄ was added as an esterification catalyst, the temperature was raised to 235 ° C., 5 hours under normal pressure (101.3 kPa), and 1 hour under reduced pressure (8 kPa). The reaction was performed.
Subsequently, after cooling to 200 degreeC and reacting under reduced pressure (20 kPa), solvent removal was performed and amorphous polyester resin was obtained. The obtained amorphous polyester resin had a weight average molecular weight (Mw) of 24,000, an acid value of 16.2 mgKOH / g, and a glass transition temperature (Tg) of 60 ° C.

[Preparation of vinyl resin particle dispersion]
(First stage polymerization)
Into a 5 L reaction vessel equipped with a stirrer, temperature sensor, cooling pipe and nitrogen introduction device, 8 parts by mass of sodium dodecyl sulfate and 3000 parts by mass of ion-exchanged water were charged, and the mixture was stirred while stirring at a rate of 230 rpm under a nitrogen stream. The temperature was raised to 80 ° C. After the temperature increase, a solution in which 10 parts by mass of potassium persulfate was dissolved in 200 parts by mass of ion-exchanged water was added, the liquid temperature was again set to 80 ° C., and a mixture of the following monomers was added dropwise over 1 hour.
Styrene 480.0 parts by mass n-butyl acrylate 250.0 parts by mass Methacrylic acid 68.0 parts by mass After the dropwise addition of the above mixture, the monomers are polymerized by heating and stirring at 80 ° C. for 2 hours, and vinyl. A resin particle dispersion was prepared.

(Second stage polymerization)
The following release agent was dissolved in the following monomer heated to 80 ° C. to prepare a release agent mixed solution.
Styrene (St) 256.0 parts by weight 2-ethylhexyl acrylate (2-EHA) 95.0 parts by weight Methacrylic acid (MAA) 30.0 parts by weight Behenate behenate (release agent, melting point 73 ° C.) 145 parts by weight Anionic Surfactant (Daiichi Kogyo Seiyaku Neogen RK) 7.8 parts by mass Ion-exchanged water 1242 parts by mass n-octyl-3-mercaptopropionate (chain transfer agent) 3.9 parts by mass Potassium persulfate 5.5 parts by mass Next, a surfactant solution in which 7.8 parts by mass of an anionic surfactant (Neogen RK manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and 1242 parts by mass of ion-exchanged water was mixed with a mechanical disperser CLEARMIX (M・ Made into Technic Co., Ltd.) and circulate, inject the above release agent mixture into it, perform mixing and dispersing for 10 minutes, emulsified particles (oil droplets) A dispersion containing was prepared.
Next, in a 5 L reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe and a nitrogen introducing device, 1100 parts by mass of ion-exchanged water and the vinyl resin particle dispersion prepared by the first stage polymerization were converted to a solid content of 55. A mass part was charged and heated to 87 ° C. A polymerization initiator in which a dispersion containing emulsion particles (oil droplets) prepared earlier and a chain transfer agent were added to this 5 L reaction vessel and 5.5 parts by weight of potassium persulfate was dissolved in 100 parts by weight of ion-exchanged water. The solution was added and the system was polymerized by heating and stirring at 87 ° C. for 1 hour to prepare a vinyl resin particle dispersion.

(3rd stage polymerization)
A solution obtained by further dissolving 8 parts by mass of potassium persulfate in 140 parts by mass of ion-exchanged water was added to the vinyl resin particle dispersion obtained by the second stage polymerization. Furthermore, the liquid mixture of the following monomer and chain transfer agent was dripped over 90 minutes on 84 degreeC temperature conditions.
Styrene (St) 367.2 parts by mass n-butyl acrylate (BA) 165.0 parts by mass Methacrylic acid (MAA) 34.3 parts by mass Methyl methacrylate (MMA) 52.5 parts by mass n-octyl-3-mercaptopro 8.0 parts by weight of pionate After completion of dropping, polymerization was carried out by heating and stirring for 2 hours, followed by cooling to 28 ° C. to prepare a vinyl resin particle dispersion.

[Production of Toner 1]
Into a reaction vessel equipped with a stirrer, a temperature sensor, and a cooling tube, 298 parts by mass of vinyl resin particle dispersion (in terms of solid content) and 2000 parts by mass of ion-exchanged water were added. Under room temperature (25 ° C.), 5 mol / L sodium hydroxide aqueous solution was added to adjust the pH to 10. Further, 7 parts by mass of the colorant particle dispersion (in terms of solid content) was added, and a solution in which 60 parts by mass of magnesium chloride was dissolved in 60 parts by mass of ion-exchanged water was added over 10 minutes at 30 ° C. with stirring. . After standing for 3 minutes, the temperature was raised to 80 ° C. over 60 minutes, and after reaching 80 ° C., 36.8 parts by mass (converted to solid content) of crystalline resin particle dispersion 3 was charged over 20 minutes. The growth rate was adjusted to 0.01 μm / min, and the growth was performed until the volume-based median diameter measured by Coulter Multisizer 3 (manufactured by Beckman Coulter, Inc.) reached 6.0 μm.
Next, 37.2 parts by mass (in terms of solid content) of amorphous polyester resin particle dispersion was added over 30 minutes, and when the supernatant of the reaction solution became transparent, 190 parts by mass of sodium chloride was added to ion-exchanged water 760. An aqueous solution dissolved in parts by mass was added to stop the growth of the particle size.
Next, the mixture was heated and stirred at 80 ° C., and particle fusion was advanced until the average circularity of the toner base particles in the dispersion reached 0.970. Then, it cooled at the predetermined | prescribed cooling rate to the temperature shown to "the 1st process" of Table I.
Then, while stirring, the temperature was raised to the temperature shown in “Second step” in Table I, and heat treatment was performed for a predetermined time. Subsequently, the temperature was changed to the temperature shown in “Third step” in Table I, and heat treatment was performed for a predetermined time. Went. Then, it cooled and liquid temperature was lowered | hung to 20 degrees C or less.
Next, solid-liquid separation was performed, and the dehydrated toner cake was redispersed in ion-exchanged water, and the solid-liquid separation was repeated three times for washing. After washing, the toner non-crystalline resin particles were dried at a temperature of Tg-20 ° C. or lower to obtain toner base particles after drying. To 100 parts by mass of the obtained toner base particles, 0.6 part by mass of hydrophobic silica particles (number average primary particle size: 12 nm, degree of hydrophobicity: 68), hydrophobic titanium oxide particles (number average primary particle size: 20 nm, Hydrophobic degree: 63) 1.0 part by mass and 1.0 part by mass of sol-gel silica (number average primary particle size = 110 nm) were added, and the peripheral speed of the rotor blade was 35 mm / h by a Henschel mixer (manufactured by Nippon Coke Industries, Ltd.). Mix for 20 minutes at 32 ° C. After mixing, coarse particles were removed using a sieve having an opening of 45 μm to obtain toner 1.

[Production of Toners 2 to 18]
In the production of the toner 1, the kind and content of the crystalline polyester resin particle dispersion (simply referred to as “dispersion” in Table I), the liquid temperature of the first step, the cooling rate, the second step and the second step Toners 2 to 18 were produced in the same manner except that the conditions of the process 3, the heat treatment temperature, and the heat treatment time were appropriately changed as shown in Table I below.

[Production of developers 1 to 18]
Developer 1 is prepared by adding a volume-based median diameter 60 μm ferrite carrier coated with a silicone resin so that the toner concentration is 6% by mass and mixing with each of the toners 1 to 18 manufactured above. -18 were produced respectively.

[Evaluation method]
<Measurement of ΔH _C and ΔH _A >
For each toner, [Delta] H C from the DSC curve obtained in the first heating in the differential scanning calorimetry as described _above, was measured [Delta] H _A. ΔH _C and ΔH _A are obtained before storage and after storage under the first or second storage conditions, respectively, and ΔH _C and ΔH _A before storage, ΔH _C (after storage) −ΔH _C (before storage) ), ΔH _A (after storage) −ΔH _A (before storage) are shown in Table II. The specific measurement method is as described above.

<Evaluation of low temperature fixability and evaluation of fluctuation range of low temperature fixability by high temperature / room temperature storage>
As an image forming apparatus, in a commercially available multifunction machine “bizhub C754” (manufactured by Konica Minolta), the developers 1 to 18 are sequentially loaded, and in an environment of normal temperature and normal humidity (temperature 20 ° C., humidity 50% RH), An unfixed solid image (attachment amount 11.3 g / m ² ) was formed on A4 size mondi color copy 90 g / m ² (manufactured by Mondi) with the image forming apparatus. Next, in the heating roller of the fixing device, the nip width is 11.2 mm, the fixing time is 34 msec, the fixing pressure is 133 kPa, the surface temperature is set to 100 ° C., and the surface temperature of the heating roller is in the range of 120 to 170 ° C. in increments of 1 ° C. Fixed while changing.
Table II shows the lowest fixing temperature at which image contamination due to fixing offset is not visually confirmed, as the minimum fixing temperature (Ta). Further, after the toner is stored under the first storage condition or the second storage condition, the same evaluation as described above is performed, and the minimum fixing temperature (Tb) under the first storage condition and the minimum fixing under the second storage condition are performed. The temperature (Tc) is shown in Table II. Further, the fluctuation range of the minimum fixing temperature under the first storage condition and the fluctuation range of the minimum fixing temperature under the second storage condition were calculated by the following formula and are shown in Table II. The fluctuation range was defined as the low temperature fixability fluctuation range due to high temperature / room temperature storage.
Fluctuation width of the minimum fixing temperature under the first storage condition = Δ [Tb (minimum fixing temperature after storage under the first storage condition) −Ta (minimum fixing temperature before storage)]
Fluctuation width of the minimum fixing temperature under the second storage condition = Δ [Tc (minimum fixing temperature after storage under the second storage condition) −Ta (minimum fixing temperature before storage)]

(Low-temperature fixability evaluation)
Evaluation was performed with the one having the highest minimum fixing temperature under the first storage condition and the second storage condition.
A: Minimum fixing temperature is less than 135 ° C. (low temperature fixing property of toner is extremely good)
○: Minimum fixing temperature of 135 ° C. or higher and lower than 145 ° C. (low temperature fixing property of toner is good)
Δ: Minimum fixing temperature of 145 ° C. or higher and lower than 155 ° C. (low temperature fixing property of toner is normal)
X: Minimum fixing temperature is 155 ° C. or higher (low temperature fixing property of toner is poor)

(Evaluation of low temperature fixability fluctuation range after storage under the first or second storage conditions)
The first storage condition and the second storage condition were evaluated with the larger fluctuation range of the low temperature fixability.
A: Low temperature fixability fluctuation range is less than 2 ° C (environmental stability of fixing performance is very good)
○: Low-temperature fixability fluctuation range is 2 ° C or higher and lower than 4 ° C (environmental stability of fixing performance is good)
Δ: Low temperature fixability fluctuation range is 4 ° C or higher and lower than 6 ° C (environmental stability of fixing performance is normal)
X: Low temperature fixability fluctuation range is 6 ° C or more (environmental stability of fixing performance is poor)

(Heat resistant storage property of toner)
0.5 g of toner was placed in a 10 mL glass bottle with an inner diameter of 21 mm, the lid was closed, and the shaker “Tap Denser KYT-2000” (manufactured by Seishin Enterprise) was shaken 600 times at room temperature, and then the lid was opened. The sample was left in an environment of a temperature of 55 ° C. and a humidity of 35% RH for 2 hours. Next, put the total amount of toner on a 48 mesh (aperture 350 μm) sieve, taking care not to crush the toner agglomerates, and set in a “powder tester” (manufactured by Hosokawa Micron). It was fixed with a certain knob nut and adjusted to a vibration intensity that would give a feed width of 1 mm. After applying vibration for 10 seconds, the ratio (mass%) of the amount of toner that passed through the sieve was measured, and the sieve passing rate (toner aggregation rate) was calculated by the following formula (A). Based on the obtained sieve passing rate, the heat-resistant storage property of the toner particles was evaluated. A sieve passing rate of 80% or more was judged as acceptable.
Formula (A): Screen passing rate (%) = (mass of toner weighed on sieve (g) −residual toner mass on sieve (g)) / mass of toner weighed on sieve (g) × 100
A: Screening rate of 90% or higher (toner has excellent heat-resistant storage property)
○: Screen passage rate of 85% or more and less than 90% (the heat-resistant storage property of the toner is good)
Δ: sieve passage rate of 80% or more and less than 85% (heat-resistant storage stability of toner is normal)
X: Sieve passing rate is less than 80% (heat resistance storage property of toner is poor)

From the results shown in Table II, it can be seen that the toner of the present invention is superior to the toner of the comparative example in terms of low-temperature fixability, low-temperature fixability fluctuation range, and heat-resistant storage stability.
Since the toner 14 of Comparative Example has a high content of crystalline resin, the productivity in the production of toner base particles is poor, and toner base particles having a desired particle diameter and circularity cannot be obtained.
Since the toner 15 of the comparative example has a low cooling rate in the first step, the toner base particles are deformed during cooling, and toner base particles having a desired particle diameter and circularity cannot be obtained.
Since the toner 16 of the comparative example has a heat treatment temperature in the second step lower than the Tg of the toner, crystallization does not proceed, and when stored under the first storage conditions, the fluctuation range of low-temperature fixability is large, and heat-resistant storage The nature was also low.
Since the heat treatment temperature in the third step was higher than the Tg of the toner, the toner 17 of the comparative example did not proceed with enthalpy relaxation, and had a wide range of low-temperature fixing fluctuation when stored under the second storage condition.
Since the toner 18 of the comparative example has a short heat treatment time in the third step, the progress of enthalpy relaxation is insufficient, and the low temperature fixing fluctuation range is large when stored under the second storage condition.

Claims (5)

An electrostatic charge image developing toner (hereinafter, also referred to as “toner”) including toner base particles containing at least a crystalline resin, an amorphous resin, and a release agent.
In the DSC curve of the toner measured by a differential scanning calorimeter,
The glass transition temperature of the toner is Tg,
When the endothermic amount based on the endothermic peak derived from the crystalline resin is ΔH _C (J / g), and the endothermic amount based on the enthalpy relaxation derived from the amorphous resin is ΔH _A (J / g),
When the toner is stored under the first storage condition [Tg + 10 ° C./humidity 50% RH / 24 hours], the following formula (1) is satisfied, and
An electrostatic charge image developing toner satisfying the following formula (2) when the toner is stored under a second storage condition [Tg-10 ° C./humidity 50% RH / 500 hours].
ΔH _C (after storage) −ΔH _C (before storage) ≦ 1.0 (J / g) Formula (1)
[Delta] H _A (after storage) - [Delta] H _A (before storage) ≦ 1.0 (J / g) (2)   The toner for developing an electrostatic charge image according to claim 1, wherein the crystalline resin has a melting point Tm in a range of 70 to 80 ° C.   The electrostatic image developing toner according to claim 1, wherein a content of the crystalline resin is in a range of 5 to 15% by mass with respect to a total resin amount in the toner. . A method for producing an electrostatic charge image developing toner for producing the electrostatic charge image development toner according to any one of claims 1 to 3,
The toner is produced through the following first to third steps using a dispersion liquid containing toner base particles containing at least a crystalline resin, an amorphous resin and a release agent, and an aqueous solvent. A method for producing a toner for developing an electrostatic charge image.
1st process: The process which cools the said dispersion liquid heated to the temperature more than melting | fusing point Tm of the said crystalline resin to the temperature below Tg of a toner with the cooling rate of 1 degree-C / min or more 2nd process: Said 1st After the step, the step of maintaining the temperature of the dispersion at a temperature of T1 (° C.) satisfying the following formula for 1 hour or more Tg + 5 ° C. ≦ T1 ≦ Tm−5 ° C. of crystalline resin
Third step: After the second step, the temperature of the dispersion is maintained at a temperature of T2 (° C.) satisfying the following formula for 1 hour or more. Tg−20 ° C. ≦ T2 <Tg In the third step,
The method for producing a toner for developing an electrostatic charge image according to claim 4, wherein the heat treatment is performed at a temperature (condition) of T2 (° C.) satisfying the following formula.
Tg-15 ° C ≦ T2 ≦ Tg-10 ° C

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