JP6679926B2 - Toner for electrostatic image development - Google Patents

Description

  The present invention relates to a toner for developing an electrostatic image, and more particularly to a toner for developing an electrostatic image which is excellent in heat-resistant storage property and has high low-temperature fixability and stability of gloss regardless of storage environment.

  In order to save energy for the purpose of speeding up image formation and reducing environmental load, a toner for electrostatic image development (hereinafter also simply referred to as toner) capable of being thermally fixed at a lower temperature is required. In order to obtain such a toner having a low temperature fixing property, a toner containing a crystalline resin such as a crystalline polyester resin having an excellent sharp melt property is known.

  For example, a toner using a crystalline polyester and an amorphous resin as a binder resin is known (see, for example, Patent Document 1). By controlling the thermal characteristics of the crystalline polyester resin and the amorphous resin in the toner, when the melting point of the crystalline polyester resin is exceeded during heat fixing, the crystalline component melts and becomes compatible with the amorphous component, A toner having excellent heat resistance can be obtained while facilitating thermal melting of the amorphous resin to fix the amorphous resin at a low temperature.

However, when the toner containing the crystalline polyester resin is stored at a high temperature for a long time, recrystallization of the crystalline polyester resin may proceed, and the fixable temperature may increase.
As a countermeasure, a toner containing a crystalline polyester resin and an amorphous polyester resin having a modified portion derived from acrylic acid has been proposed (see, for example, Patent Document 2). Increasing the affinity between the crystalline polyester resin and the amorphous polyester resin facilitates compatibility with each other, and can prevent an increase in fixing temperature even after storage at high temperature.

  Further, a toner containing a crystalline polyester resin and an amorphous polyester resin having a long chain monomer introduced at the terminal has also been proposed (for example, refer to Patent Document 3). By introducing a long-chain monomer, it is possible to create a partially oriented crystalline site in the polyester resin and to obtain stable low-temperature fixability.

  However, since the crystalline state of the crystalline polyester resin changes after being stored at a high temperature for a long time, not only the low-temperature fixability but also the glossiness tends to change, leaving room for improvement.

JP, 2006-251564, A JP 2012-22262 A JP, 2015-45848, A

  The present invention has been made in view of the above problems and situations, and the problem to be solved is to achieve excellent low-temperature fixing property and heat-resistant storage property at the same time, and electrostatic charge having high low-temperature fixing property and high stability of image glossiness regardless of storage environment. To provide a toner for image development.

  MEANS TO SOLVE THE PROBLEM In order to solve the said subject, in the process of investigating the cause of said problem etc., with amorphous polyester resin and amorphous vinyl resin, crystalline polyester resin of specific content is used as binder resin. By using it, it is possible to achieve both excellent low-temperature fixability and heat-resistant storage stability. By using a crystalline polyester resin having a weight average molecular weight (Mw) within a specific range as the crystalline polyester resin, It has been found that the rearrangement of the molecular chain of the crystalline polyester resin can be inhibited even under the conditions to suppress the crystallization, and the present invention has been completed.

That is, the problems relating to the present invention are solved by the following means.
1. A toner for developing an electrostatic charge image containing toner particles,
The toner particles contain at least a binder resin,
The binder resin contains an amorphous polyester resin, an amorphous vinyl resin and a crystalline polyester resin,
The crystalline polyester resin is a polyester resin showing crystallinity among polyester resins obtained only by polycondensation of a carboxylic acid monomer having a valence of 2 or more and an alcohol monomer having a valence of 2 or more,
The weight average molecular weight (Mw) of the crystalline polyester resin is in the range of 80,000 to 150,000,
A toner for developing an electrostatic charge image, wherein the content of the crystalline polyester resin in the binder resin is in the range of 5 to 30% by mass.

  2. 2. The toner for developing an electrostatic image according to item 1, wherein the content of the amorphous polyester resin in the binder resin is 60% by mass or more.

  3. 3. The toner for developing an electrostatic charge image according to item 1 or 2, wherein the mass ratio of the amorphous vinyl resin to the crystalline polyester resin is in the range of 20:80 to 80:20. .

4. The amorphous vinyl resin has a structure derived from a monomer having at least an acid group,
The content of the portion having a structure derived from the monomer having an acid group in the amorphous vinyl resin is in the range of 1 to 10 mass%, 1 to 3 The toner for developing an electrostatic charge image according to any one of items 1 to 6 above.

  5. 5. The toner for developing an electrostatic charge image according to any one of items 1 to 4, wherein the crystalline polyester resin has an acid value within a range of 10 to 25 mgKOH / g.

  6. 6. The electrostatic image developing toner according to any one of items 1 to 5, wherein the crystalline polyester resin has a melting point in the range of 65 to 85 ° C.

  By the above means of the present invention, it is possible to provide a toner for developing an electrostatic charge image, which has both excellent low-temperature fixability and heat-resistant storage stability, and has high low-temperature fixability and high stability of image gloss regardless of storage environment.

The mechanism of action or mechanism of action of the present invention has not been clarified, but is presumed as follows.
By using the crystalline polyester resin with the content within the above range as the binder resin together with the amorphous polyester resin and the amorphous vinyl resin, it is presumed that excellent low-temperature fixability and heat-resistant storability could be achieved at the same time. To be done.
Further, the crystalline polyester resin having a weight average molecular weight (Mw) within the above range has a bulky three-dimensional structure such as a branched or crosslinked structure and inhibits rearrangement of molecular chains of the crystalline polyester resin at high temperature. Therefore, it is presumed that recrystallization can be effectively suppressed.
Furthermore, an amorphous vinyl resin having a polarity lower than that of the amorphous polyester resin and higher than that of the crystalline polyester resin functions as a dispersant, and the crystalline polyester resin is finely dispersed uniformly in the amorphous polyester resin, which is good. It is presumed that the fact that the dispersed state could be maintained also greatly contributed to the suppression of recrystallization.
Due to the crystallization of the crystalline polyester resin, the low temperature fixability of the toner and the glossiness of the image formed by the toner are likely to change, but as described above, the recrystallization of the crystalline polyester resin can be effectively suppressed. It is presumed that the low temperature fixability and the stability of the glossiness of the image could be improved.

The toner for developing an electrostatic charge image of the present invention is a toner for developing an electrostatic charge image containing toner particles, wherein the toner particles contain at least a binder resin, and the binder resin is an amorphous polyester resin. A polyester containing an amorphous vinyl resin and a crystalline polyester resin, wherein the crystalline polyester resin is obtained only by polycondensation of a divalent or higher carboxylic acid monomer and a divalent or higher alcohol monomer. Among the resins, it is a polyester resin exhibiting crystallinity, the weight average molecular weight (Mw) of the crystalline polyester resin is in the range of 80,000 to 150,000, and the content of the crystalline polyester resin in the binder resin is , 5 to 30% by mass. This feature is a technical feature common to the claimed inventions.

  From the viewpoint of obtaining more excellent heat-resistant storage property and low-temperature fixability, the content of the amorphous polyester resin in the binder resin is preferably 60% by mass or more.

  From the viewpoint of more effectively suppressing crystal growth by uniformly finely dispersing the crystalline polyester resin, the mass ratio of the amorphous vinyl resin to the crystalline polyester resin is 20:80 to 80:20. It is preferably within the range.

  From the same viewpoint, the amorphous vinyl resin has a structure derived from a monomer having at least an acid group, and a structure derived from a monomer having the acid group in the amorphous vinyl resin It is preferable that the content of the contained portion is within the range of 1 to 10 mass%.

  From the same viewpoint, the acid value of the crystalline polyester resin is preferably in the range of 10 to 25 mgKOH / g.

  From the viewpoint of achieving both excellent low-temperature fixability and heat-resistant storage stability, the crystalline polyester resin preferably has a melting point in the range of 65 to 85 ° C.

Hereinafter, the present invention, its components, 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 after that as a lower limit and an upper limit.

[Toner for developing electrostatic image]
The electrostatic image developing toner of the present invention contains toner particles. The toner particles contain at least a binder resin, and may further contain a release agent, a colorant and the like.

[Binder resin]
The binder resin contains at least an amorphous polyester resin, an amorphous vinyl resin and a crystalline polyester resin.
Amorphous vinyl resin and crystalline polyester resin are dispersed in toner particles whose main binder is amorphous polyester resin having excellent heat resistance, from the viewpoint of achieving both heat-resistant storage stability of toner and low-temperature fixability. The state is preferred.

[Amorphous polyester resin]
The amorphous polyester resin is a non-crystalline polyester resin obtained by polymerizing a divalent or higher carboxylic acid (polyvalent carboxylic acid) monomer and a divalent or higher valent alcohol (polyhydric alcohol) monomer. A resin showing crystallinity. Amorphous means that it has a glass transition point (Tg) in an endothermic curve obtained by differential scanning calorimetry (DSC), but does not have a melting point, that is, a clear endothermic peak at the time of heating. Say. The definite endothermic peak refers to an endothermic peak having a half width within 15 ° C. in the endothermic curve when the temperature is raised at a heating rate of 10 ° C./min.

  The synthesis method of the amorphous polyester resin is not particularly limited, by utilizing a known esterification catalyst, by polymerizing (esterifying) the polyvalent carboxylic acid monomer and the polyhydric alcohol monomer, An amorphous polyester resin can be formed.

The polycarboxylic acid monomer is a compound containing two or more carboxy groups in one molecule.
Examples of the polyvalent carboxylic acid monomer that can be used in the synthesis of the amorphous polyester resin include phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, naphthalene-2,6-dicarboxylic acid, malonic acid, mesaconinic acid, Examples thereof include dimethyl isophthalate, fumaric acid, dodecenylsuccinic acid, and 1,10-dodecanedicarboxylic acid. Among these, dimethyl isophthalate, terephthalic acid, dodecenylsuccinic acid and trimellitic acid are preferable.

The polyhydric alcohol monomer is a compound containing two or more hydroxy groups in one molecule.
Examples of the polyhydric alcohol monomer that can be used for synthesizing the amorphous polyester resin include, for example, dihydric or trihydric alcohols such as ethylene glycol, propylene glycol, 1,4-butanediol, 2,3-butanediol, Ethylene oxide adduct of diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, bisphenol A ( BPA-EO), propylene oxide adduct of bisphenol A (BPA-PO), glycerin, sorbitol, 1,4-sorbitan, trimethylolpropane and the like. Among these, an ethylene oxide adduct of bisphenol A and a propylene oxide adduct of bisphenol A are preferable.

  Usable esterification catalysts include alkali metal compounds such as sodium and lithium; alkaline earth metal compounds such as magnesium and calcium; metal compounds such as aluminum, zinc, manganese, antimony, titanium, tin, zirconium and germanium; Phosphoric acid compounds; phosphoric acid compounds; amine compounds and the like.

  The polymerization temperature is not particularly limited, but it is preferably in the range of 150 to 250 ° C. The polymerization time is not particularly limited, but is preferably within the range of 0.5 to 10 hours. During the polymerization, the pressure inside the reaction system may be reduced if necessary.

  The content of the amorphous polyester resin in the binder resin is preferably 60% by mass or more from the viewpoint of obtaining a toner excellent in heat-resistant storage property, and 90 from the viewpoint of obtaining more excellent low-temperature fixability. It is preferably not more than mass%.

[Amorphous vinyl resin]
The amorphous vinyl resin is a polymer of a monomer having a vinyl group (hereinafter referred to as a vinyl monomer), which shows an amorphous property.
Examples of the amorphous vinyl resin that can be used include styrene-acrylic resin, styrene resin, and acrylic resin, and among them, styrene-acrylic resin is preferable.

  Examples of vinyl monomers that can be used include the following, and one of them can be used alone or in combination of two or more.

(1) Styrene-based monomer Styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert. -Butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene and derivatives thereof, etc. Body (2) (meth) acrylic acid ester-based monomer Methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isopropyl (meth) acrylate, isobutyl acrylate (meth) acrylate , T-butyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, Having a (meth) acrylic group such as stearyl (meth) acrylate, lauryl (meth) acrylate, phenyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate and derivatives thereof Monomers (3) Vinyl esters Vinyl propionate, vinyl acetate, vinyl benzoate, etc. (4) Vinyl ethers Vinyl methyl ether, vinyl ethyl ether, etc. (5) Vinyl ketones Vinyl methyl ketone, vinyl ethyl ketone, vinyl hexyl ketone, etc. (6) N-vinyl compounds N-vinylcarbazole, N-vinylindole, N-vinylpyrrolidone and the like (7) Other vinyl compounds such as vinylnaphthalene and vinylpyridine, acrylic acid such as acrylonitrile, methacrylonitrile and acrylamide. Stomach, such as methacrylic acid derivatives

As the vinyl monomer, it is possible to use a monomer having an ionic dissociative group such as a carboxy group, a sulfonic acid group, and a phosphoric acid group because the affinity with the amorphous polyester resin can be easily controlled. preferable.
Examples of the monomer having a carboxy group include acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumaric acid, maleic acid monoalkyl ester, and itaconic acid monoalkyl ester.
Examples of the monomer having a sulfonic acid group include styrenesulfonic acid, allylsulfosuccinic acid, 2-acrylamido-2-methylpropanesulfonic acid and the like.
Examples of the monomer having a phosphoric acid group include acid phosphooxyethyl methacrylate.

Further, a polyfunctional vinyl can be used as the vinyl monomer to obtain a polymer having a crosslinked structure.
The polyfunctional vinyls include divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol. Diacrylate etc. are mentioned.

Amorphous vinyl resin has a structure derived from a monomer having at least an acid group, the content of the portion having a structure derived from the monomer having an acid group in the amorphous vinyl resin, It is preferably in the range of 1 to 10 mass%.
The monomer having an acid group refers to a monomer having an ionic dissociative group such as the above-mentioned carboxy group, sulfonic acid group and phosphoric acid group. From the viewpoint of enhancing the affinity with the amorphous polyester resin, a monomer having a carboxy group is preferable, and as the monomer having a carboxy group, acrylic acid or methacrylic acid is particularly preferable.
The portion having a structure derived from the monomer having the acid group has a high polarity as high as that of the amorphous polyester resin. Therefore, by containing the portion within the above range, the amorphous vinyl resin The affinity of the amorphous polyester resin can be appropriately adjusted, and the dispersion state of the amorphous vinyl resin in the amorphous polyester resin is improved. Further, it is possible to suppress excessive compatibility with the crystalline polyester resin, and it is possible to obtain excellent heat resistance.

  From the viewpoint of improving the dispersibility of the crystalline polyester resin, the content of the amorphous vinyl resin in the binder resin is preferably in the range of 3 to 40% by mass, and the range of 5 to 20% by mass. More preferably within.

[Crystalline polyester resin]
The crystalline polyester resin is a known polyester resin obtained by a polycondensation reaction between a divalent or higher carboxylic acid (polyvalent carboxylic acid) monomer and a divalent or higher valent alcohol (polyhydric alcohol) monomer. , A polyester resin exhibiting crystallinity. "Crystallinity" means having a clear endothermic peak at the melting point, that is, at the time of temperature rise in the endothermic curve obtained by DSC. The definite endothermic peak refers to a peak having a half width within 15 ° C. in an endothermic curve when the temperature is raised at a heating rate of 10 ° C./min.

The crystalline polyester resin can be synthesized in the same manner as the above-mentioned amorphous polyester resin.
Examples of the polycarboxylic acid monomer that can be used for synthesizing the crystalline polyester resin include oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, n-dodecylsuccinic acid, 1,10-dodecanedicarboxylic acid. Saturated aliphatic dicarboxylic acids such as acids; cycloaliphatic dicarboxylic acids such as cyclohexanedicarboxylic acid; aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid; trivalent or higher polyvalent such as trimellitic acid and pyromellitic acid Carboxylic acids; anhydrides of these carboxylic acid compounds, alkyl esters having 1 to 3 carbon atoms, and the like.
These may be used alone or in combination of two or more.

Examples of the polyhydric alcohol monomer that can be used for synthesizing the crystalline polyester resin include 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6. -Hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, neopentyl glycol, 1,4-butenediol and other aliphatic diols; glycerin, pentaerythritol, trimethylolpropane, Examples thereof include trihydric or higher polyhydric alcohols such as sorbitol.
These may be used alone or in combination of two or more.

The weight average molecular weight (Mw) of the crystalline polyester resin is in the range of 50,000 to 200,000, and the content of the crystalline polyester resin in the binder resin is in the range of 5 to 30% by mass.
By using the crystalline polyester resin having the above content for the amorphous polyester resin and the amorphous vinyl resin, it is possible to achieve both excellent low-temperature fixability and heat-resistant storability. In addition, since the crystalline polyester resin having a weight average molecular weight (Mw) within the above range has a bulky structure such as a branched or crosslinked structure, rearrangement of molecular chains of the crystalline polyester resin at high temperature can be inhibited. It is presumed that. As a result, recrystallization can be effectively suppressed, fluctuations in low-temperature fixability and glossiness due to crystallization can be suppressed, and toner performance can be stabilized.

  From the viewpoint of more effectively suppressing recrystallization, the weight average molecular weight (Mw) of the crystalline polyester resin is preferably in the range of 80,000 to 150,000.

The weight average molecular weight (Mw) and the number average molecular weight (Mn) of the resin can be determined from the molecular weight distribution measured by gel permeation chromatography (GPC) as described below.
The sample was added to tetrahydrofuran (THF) at a concentration of 1 mg / mL, dispersed at 40 ° C. for 15 minutes using an ultrasonic disperser, and then treated with a membrane filter having a pore size of 0.2 μm to prepare a sample solution. To prepare. Using a GPC device HLC-8220 (manufactured by Tosoh Corporation) and a column TSKguardcolumn + TSKgelSuperHZ-M3 (manufactured by Tosoh Corporation), tetrahydrofuran is flown at a flow rate of 0.2 mL / min as a carrier solvent while maintaining the column temperature at 40 ° C. 10 μL of the prepared sample solution was injected into a GPC device together with a carrier solvent, the sample was detected using a refractive index detector (RI detector), and a calibration curve measured using monodisperse polystyrene standard particles was used. Calculate the molecular weight distribution of the sample. The calibration curves have molecular weights of 6 × 10 ² , 2.1 × 10 ³ , 4 × 10 ³ , 1.75 × 10 ⁴ , 5.1 × 10 ⁴ , 1.1 × 10 ⁵ , 3.9 × 10, respectively. It is prepared by measuring 10 points of polystyrene standard particles (manufactured by Pressure Chemical Co.) of ⁵ , 8.6 × 10 ⁵ , 2 × 10 ⁶ , 4.48 × 10 ⁶ .

The method for producing a crystalline polyester resin having a weight average molecular weight (Mw) within the above range is not particularly limited, but examples thereof include the following methods (1) to (3). Among them, the method (1) below is preferable because it has high crystallinity and a high molecular weight crystalline polyester resin can be obtained.
(1) A method of using a trivalent or higher polyvalent carboxylic acid monomer or a trivalent or higher polyvalent alcohol monomer.
(2) A method of addition-polymerizing an unsaturated dicarboxylic acid monomer or an unsaturated dialcohol monomer.
(3) As the crystalline polyester resin, a hybrid resin in which a crystalline polyester resin segment and an amorphous resin segment are chemically bonded to form a copolymer such as a block copolymer or a graft copolymer is used. Method.

(Hybrid resin)
In the above hybrid resin, the crystalline polyester resin segment refers to a resin portion having a structure derived from a crystalline Poerister resin, and the amorphous resin segment refers to a resin portion having a structure derived from an amorphous resin. .

The content of the crystalline polyester resin segment in the hybrid resin is preferably in the range of 50 to 98 mass% from the viewpoint of providing the hybrid resin with sufficient crystallinity.
The constituent component and content of each segment such as the crystalline polyester resin segment in the hybrid resin can be measured by, for example, NMR analysis, methylation reaction P-GC / MS analysis, or the like.

The amorphous resin segment is not particularly limited as long as it exhibits amorphousness, and examples thereof include an amorphous vinyl resin segment, an amorphous urethane resin segment, and an amorphous urea resin segment. Among them, if the amorphous resin segment has a structure derived from an amorphous resin such as an amorphous polyester resin or an amorphous vinyl resin used as a binder resin, the amorphous resin in the binder resin is The compatibility with the resin is enhanced, and the charging uniformity and the like can be obtained.
The content of the amorphous resin segment in the hybrid resin can be in the range of 5 to 20% by mass.

Examples of the method for synthesizing the hybrid resin include the following synthetic methods (1) to (3).
(1) A crystalline polyester resin segment is made amorphous by reacting a bi-reactive monomer with a crystalline polyester resin prepared in advance and then reacting the monomer as a raw material of the amorphous resin. Method of chemically bonding resin segment (2) After reacting a bireactive monomer with an amorphous resin prepared in advance, a polyvalent carboxylic acid monomer and a polyhydric alcohol, which are raw materials of the crystalline polyester resin Method of reacting monomer to chemically bond crystalline polyester resin segment to amorphous resin segment (3) Prepare both crystalline polyester resin segment and amorphous resin segment with both-reactive monomer Method of reacting to chemically bond each segment

The bireactive monomer is a monomer having a substituent capable of reacting with both the crystalline polyester resin and the amorphous resin, and a polymerizable unsaturated group.
As the bireactive monomer, for example, (meth) acrylic acid, fumaric acid, maleic acid, maleic anhydride or the like can be used.

The mass ratio of the amorphous vinyl resin and the crystalline polyester resin used as the binder resin is preferably in the range of 20:80 to 80:20.
When the mass ratio is within this range, the dispersion state of the amorphous vinyl resin and the crystalline polyester resin can be controlled so that the amorphous polyester resin can be uniformly finely dispersed in the toner particles having the main binder. . Thereby, the crystal growth due to the aggregation of the domains of the crystalline polyester resin can be suppressed even at a high temperature, and the change in the low temperature fixability and the glossiness due to the crystallization can be suppressed more effectively.

The acid value of the crystalline polyester resin is preferably in the range of 10 to 25 mgKOH / g.
When the acid value is within the above range, the balance between the crystalline polyester resin exhibiting hydrophilicity and the amorphous polyester resin exhibiting hydrophobicity can be appropriately adjusted, and the amorphous polyester resin is used as the main binder. Since the size of the domains of the crystalline polyester resin dispersed in the toner particles is reduced, it is possible to suppress crystal growth due to aggregation when stored at high temperature. As a result, stable low-temperature fixability and gloss can be obtained even at high temperatures.

  The acid value represents the mass of potassium hydroxide (KOH) necessary for neutralizing the acid contained in 1 g of the sample in mg unit. The acid value of the resin is measured by the following procedure according to JIS K0070-1966.

(Preparation of reagents)
A phenolphthalein solution is prepared by dissolving 1.0 g of phenolphthalein in 90 ml of ethyl alcohol (95% by volume) and adding ion-exchanged water to 100 ml. 7 g of JIS special grade potassium hydroxide is dissolved in 5 ml of ion-exchanged water, and ethyl alcohol (95% by volume) is added to make 1 liter. A potassium hydroxide solution is prepared by placing the solution in an alkali resistant container for 3 days so that it does not come into contact with carbon dioxide gas, and then filtering it. Standardization follows the description of JIS K0070-1966.

(main exam)
2.0 g of the crushed sample is precisely weighed in a 200 ml Erlenmeyer flask, 100 ml of a mixed solution of toluene / ethanol (2: 1) is added, and the mixture is dissolved for 5 hours. Then, a few drops of the phenolphthalein solution prepared as an indicator are added, and titration is performed using the prepared potassium hydroxide solution. The end point of the titration is when the light red color of the indicator continues for about 30 seconds.
(Blank test)
The same operation as the above-mentioned main test is performed except that the sample is not used (that is, only the mixed solution of toluene / ethanol (2: 1) is used).

The acid value is calculated by substituting the titration results of the main test and the blank test into the following formula (1).
Formula (1) A = [(B−C) × f × 5.6] / S
A: Acid value (mgKOH / g)
B: Amount of potassium hydroxide solution added during blank test (ml)
C: Amount of potassium hydroxide solution added in this test (ml)
f: Factor of 0.1 mol / liter potassium hydroxide ethanol solution S: Mass of sample (g)

  The melting point (Tm) of the crystalline polyester resin is preferably within the range of 65 to 85 ° C. from the viewpoint of achieving both excellent low temperature fixability and heat resistance.

The melting point (Tm) of the crystalline polyester resin is the temperature at the peak top of the endothermic peak, and can be measured by DSC using Diamond DSC (manufactured by Perkin Elmer).
Specifically, an aluminum pan KITNO. The sample was sealed in B0143013, set in a sample holder of a thermal analyzer Diamond DSC (manufactured by Perkin Elmer), and the temperature was changed in the order of heating, cooling, and heating. The temperature is raised from room temperature (25 ° C) during the first heating, from 0 ° C during the second heating to 150 ° C at a heating rate of 10 ° C / min, and 150 ° C is maintained for 5 minutes. The temperature is decreased from 150 ° C. to 0 ° C. at a temperature decrease rate of ° C./min and the temperature of 0 ° C. is maintained for 5 minutes. The temperature at the peak top of the endothermic peak in the endothermic curve obtained during the second heating is measured as the melting point.

〔Release agent〕
The release agent is not particularly limited, and various known waxes can be used. Examples of release agents that can be used include polyolefin waxes such as polyethylene wax and polypropylene wax, branched hydrocarbon waxes such as microcrystalline wax, long-chain hydrocarbon waxes such as paraffin wax and sazol wax, and distearyl ketone. Such as dialkyl ketone wax, carnauba wax, montan wax, behenic acid behenate, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18- Ester wax such as octadecanediol distearate, trimellitic acid tristearyl, distearyl maleate, ethylenediamine behenylamide, trimellitic acid tristearylami Amide waxes and the like.

The content of the release agent can be usually in the range of 1 to 30 parts by mass, and preferably in the range of 5 to 20 parts by mass with respect to 100 parts by mass of the binder resin. When the content of the release agent is within the above range, sufficient fixing separability can be obtained.
The content of the release agent in the toner particles is preferably in the range of 3 to 15% by mass.

(Coloring agent)
As the colorant, generally known dyes and pigments can be used.
As a colorant for obtaining a black toner, furnace black, carbon black such as channel black, magnetite, magnetic materials such as ferrite, dyes, various known inorganic pigments including non-magnetic iron oxide can be arbitrarily used. Can be used.

As the colorant for obtaining the color toner, any known dyes, organic pigments and the like can be arbitrarily used. Examples of the organic pigment include C.I. I. Pigment Red 5, 48: 1, 53: 1, 57: 1, 81: 4, 122, 139, 144, 149, 166, 177, 178, 222, 238. 269, C.I. I. Pigment Yellow 14, the same 17, the same 74, the same 93, the same 94, the same 138, the same 155, the same 180, the same 185, C.I. I. Pigment Orange 31, the same 43, C.I. I. Pigment Blue 15: 3, the same 60, the same 76, and the like. Examples of the dye include C.I. I. Solvent Red 1, the same 49, the same 52, the same 58, the same 68, the same 11, the same 122, C.I. I. Solvent Yellow 19, the same 44, the same 77, the same 79, the same 81, the same 82, the same 93, the same 98, the same 103, the same 104, the same 112, the same 162, C.I. I. Solvent Blue 25, the same 36, the same 69, the same 70, the same 93, the same 95 and the like.
As for the colorant for obtaining the toner of each color, one type may be used alone or two or more types may be used in combination for each color.
The content of the colorant is preferably in the range of 1 to 10 parts by mass, and more preferably in the range of 2 to 8 parts by mass with respect to 100 parts by mass of the binder resin.

The toner particles may contain a charge control agent, an external additive, etc., if necessary.
(Charge control agent)
As the charge control agent, known compounds such as nigrosine dye, metal salt of naphthenic acid or higher fatty acid, alkoxylated amine, quaternary ammonium salt, azo metal complex, metal salt of salicylic acid and the like can be used. By using the charge control agent, a toner having excellent charging characteristics can be obtained.
The content of the charge control agent can be usually in the range of 0.1 to 5.0 parts by mass with respect to 100 parts by mass of the binder resin.

[External additive]
The toner particles can be used as a toner as they are, but may be treated with an external additive such as a fluidizing agent and a cleaning aid in order to improve fluidity, charging property, cleaning property and the like.

Examples of the external additive include fine particles of inorganic oxide such as silica fine particles, fine particles of alumina and fine particles of titanium oxide, fine particles of inorganic stearic acid compound such as fine particles of aluminum stearate and fine particles of zinc stearate, strontium titanate and zinc titanate. Examples include fine particles of inorganic titanate compounds. These can be used alone or in combination of two or more.
It is preferable that these inorganic particles have been subjected to a gloss treatment with a silane coupling agent, a titanium coupling agent, a higher fatty acid, a silicone oil, or the like, from the viewpoint of improving heat-resistant storage properties and environmental stability.

  The added amount of the external additive (when a plurality of external additives are used, the total added amount) is preferably in the range of 0.05 to 5 parts by mass with respect to 100 parts by mass of the toner, and 0.1 More preferably, it is within the range of 3 parts by mass.

[Core / shell structure]
The toner particles can be used as a toner as they are, but even a toner particle having a multilayer structure such as a core-shell structure including the toner particles as core particles and the core particles and a shell layer coating the surface thereof can be used. Good. The shell layer does not have to 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) and a scanning probe microscope (SPM).

  In the case of the core / shell structure, the characteristics such as glass transition point, melting point and hardness can be made different between the core particle and the shell layer, and the toner particle can be designed according to the purpose. For example, a resin having a relatively high glass transition point (Tg) is 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 point (Tg). The shell layer can be formed. The shell layer preferably contains an amorphous resin.

[Particle size of toner particles]
As the average particle diameter of the toner particles, the volume-based median diameter (d ₅₀ ) is preferably in the range of 3 to 10 μm, and more preferably in the range of ₅ to 8 μm.
Within the above range, high reproducibility can be obtained even for a very fine dot image of 1200 dpi level.
The average particle size of the toner particles can be controlled by the concentration of the aggregating agent used during production, the amount of the organic solvent added, the fusing time, the composition of the binder resin, and the like.

To measure the volume-based median diameter (d ₅₀ ) of toner particles, use a measuring device in which a computer system equipped with software V3.51 for data processing is connected to Multisizer 3 (manufactured by Beckman Coulter). You can
Specifically, the measurement sample (toner) is added to a surfactant solution (for example, a surfactant solution obtained by diluting a neutral detergent containing a surfactant component 10 times with pure water for the purpose of dispersing toner particles). Then, ultrasonic dispersion is carried out to prepare a toner particle dispersion liquid. This toner particle dispersion is pipetted into a beaker containing ISOTON II (manufactured by Beckman Coulter, Inc.) in a sample stand until the indicated concentration on the measuring device reaches 8%. Here, by setting this concentration, a reproducible measurement value can be obtained. Then, in the measuring device, the number of particles to be measured was set to 25,000, the aperture diameter was set to 100 μm, and the frequency value was calculated by dividing the range of 2 to 60 μm, which is the measurement range, into 256. % Particle size is obtained as the volume-based median diameter (d ₅₀ ).

[Average circularity of toner particles]
The toner particles preferably have an average circularity within the range of 0.930 to 1.000, and within the range of 0.950 to 0.995, from the viewpoint of improving the stability of charging characteristics and the low temperature fixability. Is more preferable.
When the average circularity is within the above range, individual toner particles are less likely to be crushed. As a result, it is possible to suppress the contamination of the frictional charge imparting member, stabilize the chargeability of the toner, and improve the image quality of the image formed.

The average circularity of the toner particles can be measured using FPIA-2100 (manufactured by Sysmex).
Specifically, the measurement sample (toner) is conditioned with an aqueous solution containing a surfactant, and ultrasonic dispersion treatment is performed for 1 minute to disperse the sample. Thereafter, the FPIA-2100 (manufactured by Sysmex) is used to perform imaging in an HPF (high-magnification imaging) mode under measurement conditions at an appropriate density of 3000 to 10,000 HPF detections. When the HPF detection number is within the above range, reproducible measurement values can be obtained. The circularity of each toner particle is calculated from the photographed particle image according to the following formula (I), and the circularity of each toner particle is added and divided by the total number of toner particles to obtain the average circularity.
Formula (I)
Circularity = (perimeter of a circle having the same projected area as the particle image) / (perimeter of the particle projected image)

(Developer)
The toner for developing an electrostatic image of the present invention can be used as a magnetic or non-magnetic one-component developer, or may be mixed with a carrier and used as a two-component developer. When the toner is used as a two-component developer, magnetic particles made of conventionally known materials such as metals such as iron, ferrite and magnetite, alloys of those metals with metals such as lead and lead are used as the carrier. In particular, ferrite particles are preferable.

Further, as the carrier, a coated carrier in which the surface of magnetic particles is coated with a coating agent such as a resin, or a dispersion type carrier in which fine magnetic powder is dispersed in a binder resin may be used.
The volume-based median diameter (d ₅₀ ) of the carrier is preferably in the range of 20 to 100 μm, more preferably in the range of 25 to 80 μm.
The volume-based median diameter (d ₅₀ ) of the carrier can be measured, for example, by a laser diffraction particle size distribution analyzer HELOS (manufactured by SYMPATEC) equipped with a wet disperser.

[Method for producing toner for developing electrostatic image]
Examples of the method for producing the toner for developing an electrostatic image of the present invention include a suspension polymerization method, an emulsion aggregation method, and other known methods. Among them, the emulsion aggregation method is preferably used. According to the emulsion aggregation method, it is possible to easily reduce the particle size of the toner particles from the viewpoint of manufacturing cost and manufacturing stability.

  The method for producing toner particles by an emulsion aggregation method is an aqueous dispersion of amorphous polyester resin particles, an aqueous dispersion of amorphous vinyl resin particles, an aqueous dispersion of colorant particles, and a crystalline polyester resin particle. This is a method of forming toner particles by mixing an aqueous dispersion with an amorphous polyester resin, amorphous vinyl resin particles, colorant particles, and crystalline polyester resin particles.

Here, the aqueous dispersion refers to one in which particles are dispersed in the aqueous medium, and the aqueous medium refers to one in which 50% by mass or more of the main component of the aqueous medium is water.
Examples of components other than water in the aqueous medium include organic solvents that are soluble in water, such as methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, and tetrahydrofuran. Of these, alcohol-based organic solvents such as methanol, ethanol, isopropanol and butanol, which are organic solvents that do not dissolve the resin, are preferable.

Hereinafter, an example of the steps of the method for producing a toner by the emulsion aggregation method will be described.
(Process (0))
In step (0), an aqueous dispersion of amorphous polyester resin particles is prepared.
Specifically, an amorphous polyester resin is synthesized, dissolved or dispersed in an organic solvent to prepare an oil phase liquid, and the oil phase liquid is phase-inverted to emulsify the amorphous polyester resin particles in an aqueous medium. To disperse. By controlling the particle size of the oil droplets to a desired particle size and then removing the organic solvent, an aqueous dispersion of the amorphous polyester resin can be obtained.

As the organic solvent used in the oil phase liquid, those having a low boiling point and low solubility in water are preferable from the viewpoint of easy removal treatment after formation of oil droplets. Specific examples include methyl acetate, ethyl acetate, methyl ethyl ketone, methyl isobutyl ketone, toluene, xylene and the like. These may be used alone or in combination of two or more.
The amount of the organic solvent used is usually in the range of 1 to 300 parts by mass with respect to 100 parts by mass of the crystalline polyester resin.
Emulsification and dispersion of the oil phase liquid can be performed by utilizing mechanical energy.

The amount of the aqueous medium used is preferably within the range of 50 to 2000 parts by mass, more preferably within the range of 100 to 1000 parts by mass with respect to 100 parts by mass of the oil phase liquid.
A surfactant or the like may be added to the aqueous medium for the purpose of improving the dispersion stability of oil droplets.

(Surfactant)
As the surfactant, for example, dodecyl ammonium bromide, a cationic surfactant such as dodecyl trimethyl ammonium bromide, dodecyl polyoxyethylene ether, hexadecyl polyoxyethylene ether, norylphenyl polyoxyethylene ether, lauryl polyoxyethylene ether, Known surfactants such as anionic surfactants such as sorbitan monooleate polyoxyethylene ether, nonionic surfactants such as sodium stearate, sodium laurate, sodium lauryl sulfate, sodium dodecylbenzenesulfonate and sodium dodecyl sulfate. Agents can be used.

(Process (1))
In step (1), an aqueous dispersion of amorphous vinyl resin particles is prepared.
A mini-emulsion polymerization method can be used for the preparation of the aqueous dispersion of the amorphous vinyl resin particles. For example, a vinyl monomer and a water-soluble radical polymerization initiator are added to an aqueous medium containing a surfactant as described above, and mechanical energy is applied to form droplets. The radicals from the radical polymerization initiator cause the polymerization reaction to proceed in the droplet. An oil-soluble polymerization initiator may be contained in the droplets.

  The amorphous vinyl resin particles may have a multilayer structure of two or more layers in which the composition of each layer is different. A dispersion liquid of amorphous vinyl resin particles having a multilayer structure can be obtained by a multi-step polymerization reaction. For example, a dispersion liquid of amorphous vinyl resin particles having a two-layer structure is prepared by polymerizing a vinyl monomer (first stage polymerization) to prepare a dispersion liquid of amorphous vinyl resin particles, and then further adding a polymerization initiator. It can be obtained by adding a vinyl monomer and vinyl monomer and polymerizing (second stage polymerization).

(Polymerization initiator)
As the polymerization initiator, various conventionally known ones can be used. As the polymerization initiator, although persulfates (potassium persulfate, ammonium persulfate, etc.) can be preferably used, 4,4′-azobis-4-cyanovaleric acid and its salts, 2,2′-azobis (2-amidinopropane) ) Azo compounds such as salts, peroxide compounds, azobisisobutyronitrile and the like may be used.

(Chain transfer agent)
A commonly used chain transfer agent can be added to the aqueous medium for the purpose of adjusting the molecular weight of the amorphous vinyl resin. The chain transfer agent is not particularly limited, and examples thereof include mercaptans such as 2-chloroethanol, octyl mercaptan, dodecyl mercaptan, t-dodecyl mercaptan, and styrene dimer.

When manufacturing a toner particle containing an additive such as a release agent or a charge control agent, the additive is introduced into the toner particle by dissolving or dispersing the additive in a solution of a vinyl monomer in advance. be able to.
In this way, it is preferable to disperse the additive in advance with the amorphous vinyl resin particles, but a dispersion liquid of the additive particles is prepared separately from the amorphous vinyl resin, and the amorphous polyester resin particles such as It is also possible to introduce it into the toner particles by mixing it with other dispersion liquid and aggregating the additive particles together with the amorphous polyester resin particles and the like.

The average particle diameter of the amorphous vinyl resin particles is preferably in the range of 100 to 400 nm in terms of volume-based median diameter (d ₅₀ ).
The volume-based median diameter (d ₅₀ ) of the amorphous vinyl resin particles can be measured using Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.).

(Process (2))
In step (2), an aqueous dispersion of crystalline polyester resin particles is prepared.
The aqueous dispersion of crystalline polyester resin particles can be prepared in the same manner as the above-mentioned amorphous polyester resin aqueous dispersion.

The average particle diameter of the crystalline polyester resin particles is preferably in the range of 100 to 400 nm in terms of volume-based median diameter (d ₅₀ ).
The volume-based median diameter (d ₅₀ ) of the crystalline polyester resin particles can be measured using Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.).

(Process (3))
In the step (3), the colorant is dispersed in the aqueous medium in the form of fine particles to prepare an aqueous dispersion of the colorant particles.

The aqueous dispersion of colorant particles can be obtained by dispersing the colorant in an aqueous medium to which a surfactant is added at a critical micelle concentration (CMC) or higher.
Dispersion of the colorant can be carried out by utilizing mechanical energy, and the disperser used is not particularly limited, but preferably an ultrasonic disperser, a mechanical homogenizer, a Manton-Gaulin or a pressure homogenizer. Examples of the medium-type disperser include a pressure disperser, a sand grinder, a Getzman mill, and a diamond fine mill.

The colorant particles in the aqueous dispersion preferably have a volume-based median diameter (d ₅₀ ) in the range of 10 to 300 nm, more preferably in the range of 100 to 200 nm, and in the range of 100 to 150 nm. It is particularly preferable that
The volume-based median diameter (d ₅₀ ) of the colorant particles can be measured using Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.).

(Process (4))
In the step (4), the amorphous polyester resin particles, the amorphous vinyl resin particles, the colorant particles and the crystalline polyester resin particles, and the particles of other toner constituent components are aggregated to form toner particles.
Specifically, by adding an aggregating agent having a critical aggregation concentration or higher to a system in which an aqueous medium and an aqueous dispersion liquid of each particle are mixed, and by bringing the temperature to a temperature higher than the glass transition temperature (Tg) of the amorphous vinyl resin particles. Agglomerate.

(Flocculant)
The aggregating agent is not particularly limited, but one selected from metal salts such as alkali metal salts and alkaline earth metal salts is preferably used. Examples of the metal salt include monovalent metal salts such as sodium, potassium and lithium, divalent metal salts such as calcium, magnesium, manganese and copper, and trivalent metal salts such as iron and aluminum. Specific examples of the metal salt 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 because it can proceed.
These may be used alone or in combination of two or more.

(Process (5))
In the step (5), the toner particles formed in the step (4) are aged so as to be controlled to have a desired shape. Step (5) can be performed as necessary.
Specifically, the dispersion liquid of toner particles obtained in step (4) is heated and stirred, and the heating temperature, stirring speed, heating time, etc. are adjusted so that the toner particles have a desired circularity.

(Process (4B))
In the step (4B), the toner particles obtained in the step (4) or (5) are used as core particles to form a shell layer that covers at least a part of the surfaces of the core particles. The step (4B) may be performed when forming toner particles having a core / shell structure.

In the case of forming toner particles having a core / shell structure, the resin forming the shell layer is dispersed in an aqueous medium to prepare a dispersion liquid of the resin particles for the shell layer, which is obtained by the above step (4) or (5). The resin particles of the shell layer are aggregated and fused on the surface of the toner particles by adding to the dispersion liquid of the obtained toner particles. As a result, a dispersion liquid of toner particles having a core / shell structure can be obtained.
Since the resin particles of the shell layer are more strongly aggregated and fused to the core particles, heat treatment can be performed subsequent to the shell formation step. The heat treatment may be performed until the toner particles having the desired circularity are obtained.

(Process (6))
In step (6), the dispersion liquid of toner particles is cooled. As conditions for the cooling treatment, it is preferable to cool at a cooling rate of 1 to 20 ° C./min. The specific method of the cooling treatment is not particularly limited, and examples thereof include a method of cooling by introducing a refrigerant from the outside of the reaction vessel and a method of directly charging cold water into the reaction system for cooling. You can

(Process (7))
In the step (7), the toner particles are solid-liquid separated from the cooled dispersion liquid of the toner particles, and the toner cake (wet toner particles molded into a cake) obtained by the solid-liquid separation is used as a surfactant. Remove the deposits such as coagulants and coagulants and wash.
The solid-liquid separation is not particularly limited, and a centrifugal separation method, a vacuum filtration method using a Nutsche or the like, a filtration method using a filter press or the like can be used. In the washing, it is preferable to wash with water until the electric conductivity of the filtrate becomes 10 μS / cm.

(Process (8))
In step (8), the washed toner cake is dried.
The toner cake can be dried by using a spray dryer, a vacuum freeze dryer, a vacuum dryer, etc., a stationary shelf dryer, a mobile shelf dryer, a fluidized bed dryer, a rotary dryer, a stirring dryer. It is preferable to use a machine or the like.
The water content of the toner particles after drying is preferably 5% by mass or less, and more preferably 2% by mass or less.
When the toner particles after drying are aggregated by a weak attraction force between particles, the aggregate may be crushed. As the crushing treatment device, a mechanical crushing device such as a jet mill, a Henschel mixer, a coffee mill, a food processor or the like can be used.

(Process (9))
In step (9), an external additive is added to the toner particles. Step (9) can be performed as necessary.
A mechanical mixer such as a Henschel mixer or a coffee mill can be used for adding the external additive.

  Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In the examples, “part” or “%” is used, but unless otherwise specified, “part by mass” or “% by mass” is indicated.

(Preparation of Dispersion Liquid (W) of Release Agent Particles)
Hydrocarbon wax as a release agent (manufactured by Nippon Seiro Co., Ltd., trade name: FNP0090, melting point 90.2 ° C) 450 parts by mass, sodium lauryl sulfate 50 parts by mass and ion exchange water 3500 parts by mass are heated to 80 ° C. And was sufficiently dispersed by using Ultra Tarax T50 manufactured by IKA. After that, dispersion treatment with a pressure discharge type Gohlin homogenizer was carried out to prepare a dispersion liquid (W) of release agent particles. The volume-based median diameter of the release agent particles in this dispersion was measured with a laser diffraction particle size distribution analyzer LA-750 (manufactured by HORIBA), and it was 220 nm.

(Aqueous dispersion of colorant particles (Bk))
While stirring a solution prepared by adding 90 parts by mass of sodium lauryl sulfate to 1600 parts by mass of ion-exchanged water, 420 parts by mass of carbon black (Regal 330R: manufactured by Cabot) was gradually added. Furthermore, dispersion treatment was carried out using a stirrer Clearmix (manufactured by M Technique Co., Ltd.) to prepare an aqueous dispersion (Bk) of colorant particles.
The volume-based median diameter (d ₅₀ ) of the colorant particles in the obtained aqueous dispersion (Bk) was 110 nm when measured using Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.).

(Amorphous polyester resin (A1))
In a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple, 50.2 parts by mass of bisphenol A ethylene oxide 2 mol adduct (BPA-EO), bisphenol A propylene oxide 2 mol adduct (BPA) were added. -PO) 249.8 parts by mass, terephthalic acid (TPA) 75.3 parts by mass, dodecenylsuccinic acid (DDSA) 36 parts by mass, and an esterification catalyst (tin octylate) 2.0 parts by mass are added, and the mixture is heated at 230 ° C for 5 hours. A polycondensation reaction was performed. Then, the pressure was reduced to 8 kPa and the reaction was carried out for 1 hour to obtain an amorphous polyester resin (A1). The obtained amorphous polyester resin (A1) had a glass transition temperature (Tg) of 61.1 ° C. and a weight average molecular weight (Mw) of 18,500.

  The glass transition point (Tg) was measured using Diamond DSC (manufactured by Perkin Elmer). Specifically, 1.5 mg of the sample was enclosed in an aluminum pan, and the temperature was changed in the order of heating, cooling, and heating. The temperature was raised from room temperature (25 ° C.) during the first heating to 0 ° C. during the second heating at a heating rate of 10 ° C./min to 150 ° C., and the temperature of 150 ° C. was maintained for 5 minutes. During cooling, the temperature was decreased from 150 ° C. to 0 ° C. at a temperature decrease rate of 10 ° C./min, and the temperature of 0 ° C. was maintained for 5 minutes. The shift of the baseline was observed in the measurement curve obtained during the second heating, and the intersection point between the extension line of the baseline before the shift and the tangent line indicating the maximum slope of the shifted portion of the baseline was measured at the glass transition point (Tg). ). An empty aluminum pan was used as a reference.

The weight average molecular weight (Mw) was determined from the molecular weight distribution measured by GPC.
Specifically, the measurement sample was added to tetrahydrofuran (THF) at a concentration of 1 mg / mL, dispersed at room temperature for 5 minutes using an ultrasonic disperser, and then treated with a membrane filter having a pore size of 0.2 μm. Then, a sample solution was prepared. Using a GPC device HLC-8120GPC (manufactured by Tosoh Corporation) and a column TSKguardcolumn + TSKgelSuperHZ-m3 (manufactured by Tosoh Corporation), while maintaining the column temperature at 40 ° C., tetrahydrofuran as a carrier solvent was flowed at a flow rate of 0.2 mL / min. . 10 μL of the prepared sample solution was injected into a GPC device together with a carrier solvent, the sample was detected using a refractive index detector (RI detector), and a calibration curve measured using monodisperse polystyrene standard particles was used. , The molecular weight distribution of the sample was calculated. The calibration curves have molecular weights of 6 × 10 ² , 2.1 × 10 ³ , 4 × 10 ³ , 1.75 × 10 ⁴ , 5.1 × 10 ⁴ , 1.1 × 10 ⁵ , 3.9 × 10, respectively. It was prepared by measuring 10 points of polystyrene standard particles (manufactured by Pressure Chemical Co.) of ⁵ , 8.6 × 10 ⁵ , 2 × 10 ⁶ , 4.48 × 10 ⁶ .

(Amorphous polyester resin (A2))
In the production of the amorphous polyester resin (A1), an amorphous polyester resin (A2) was obtained in the same manner except that the addition amount of the monomer was changed as shown in Table 1 below. The obtained amorphous polyester resin (A2) had a glass transition temperature (Tg) of 59.3 ° C. and a weight average molecular weight (Mw) of 21,000.

(Amorphous polyester resin (A3))
In a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple, 48.3 parts by mass of bisphenol A ethylene oxide 2 mol adduct (BPA-EO), 2 mol of bisphenol A propylene oxide adduct (BPA) were added. -PO) 251.2 parts by mass, terephthalic acid (TPA) 81.8 parts by mass, fumaric acid (FA) 36.1 parts by mass, and an esterification catalyst (tin octylate) 2.0 parts by mass at 230 ° C. After polycondensation reaction for 5 hours, it was cooled to 160 ° C. Further, 20.1 parts by mass of trimellitic acid (TMA) was added, polycondensation reaction was carried out at 230 ° C. for 3 hours, and then reaction was carried out at 8 kPa for 1 hour to obtain an amorphous polyester resin (A3). The obtained amorphous polyester resin (A3) had a glass transition temperature (Tg) of 60.4 ° C. and a weight average molecular weight (Mw) of 34500.

(Amorphous polyester resin particle dispersion (a1))
100 parts by mass of the amorphous polyester resin (A1) was pulverized with a Randelmill RM type (manufactured by Tokuju Kosakusho Co., Ltd.) and mixed with 638 parts by mass of a 0.26% by mass sodium lauryl sulfate solution prepared in advance. The volume-based median diameter (d ₅₀ ) was 160 nm by agitating the mixed solution and ultrasonically dispersing with V-LEVEL, 300 μA for 60 minutes using an ultrasonic homogenizer US-150T (manufactured by Nippon Seiki Seisakusho Co., Ltd.). To prepare a dispersion liquid (a1) of amorphous polyester resin particles.

(Amorphous polyester resin particle dispersion (a2))
Amorphous polyester resin particles were prepared in the same manner except that the amorphous polyester resin (A1) was changed to the amorphous polyester resin (A2) in the preparation of the dispersion liquid (a1) of the amorphous polyester resin particles. A dispersion (a2) of was prepared.

(Amorphous polyester resin particle dispersion (a3))
Amorphous polyester resin particles were prepared in the same manner except that the amorphous polyester resin (A1) was changed to the amorphous polyester resin (A3) in the preparation of the dispersion liquid (a1) of the amorphous polyester resin particles. A dispersion (a3) of was prepared.

(Dispersion of amorphous vinyl resin particles (b1))
A 5 L reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introducing device was charged with 5.0 parts by mass of sodium lauryl sulfate and 2500 parts by mass of ion-exchanged water, and stirred at a stirring speed of 230 rpm under a nitrogen stream. Meanwhile, the internal temperature was raised to 80 ° C.
Next, a solution prepared by dissolving 15.0 parts by mass of potassium persulfate (KPS) in 287 parts by mass of ion-exchanged water was added, and the liquid temperature was set to 80 ° C. Further, a monomer mixture liquid consisting of 888.0 parts by mass of styrene (St), 252.0 parts by mass of n-butyl acrylate (BA) and 60.0 parts by mass of methacrylic acid (MAA) was added dropwise over 2 hours. After completion of dropping, polymerization was carried out by heating and stirring at 80 ° C. for 2 hours to prepare a dispersion liquid (b1) of amorphous vinyl resin (B1) particles having a volume-based median diameter (d ₅₀ ) of 110 nm. .

  The glass transition temperature (Tg) of the amorphous vinyl resin (B1) was 55.0 ° C, and the weight average molecular weight (Mw) was 18500. The glass transition temperature (Tg) and the weight average molecular weight (Mw) were measured in the same manner as the above amorphous polyester resin.

(Dispersion of amorphous vinyl resin particles (b2) to (b7))
In the preparation of the dispersion liquid (b1) of amorphous vinyl resin (B1) particles, the amorphous vinyl resins (B2) to ((B2) to ( B7) Dispersions (b2) to (b7) of particles were prepared. In Table 2 below, AA represents acrylic acid.

(Crystalline polyester resin (C1))
In a reaction vessel equipped with a stirrer, a thermometer, a condenser, and a nitrogen gas introduction tube, 199.5 parts by mass of 1,10-decanedicarboxylic acid, 3.6 parts by mass of trimellitic acid, and 101.5 of 1,6-hexanediol were added. Into the reaction vessel, dry nitrogen gas was substituted. Then, 1.5 parts by mass of tin dioctanoate was added, and the mixture was stirred and reacted at 160 ° C. for 3 hours under a nitrogen gas stream. After further raising the temperature to 180 ° C. over 1.5 hours, the pressure inside the reaction vessel was reduced to 8 kPa and the reaction was performed for 3 hours to obtain a crystalline polyester resin (C1). The crystalline polyester resin (C1) obtained had a melting point (Tm) of 70 ° C., a weight average molecular weight (Mw) of 138600 and an acid value of 15.2.

  The melting point (Tm) was measured by DSC. Specifically, an aluminum pan KITNO. The sample was sealed in B0143013, set in a sample holder of a thermal analyzer Diamond DSC (manufactured by Perkin Elmer), and the temperature was changed in the order of heating, cooling, and heating. At the time of the first heating, the temperature is raised from room temperature (25 ° C) to 0 ° C at the time of the second heating to 150 ° C at a heating rate of 10 ° C / min, and the temperature of 150 ° C is maintained for 5 minutes. The temperature was decreased from 150 ° C. to 0 ° C. at a temperature decrease rate of 10 ° C./min, and the temperature of 0 ° C. was maintained for 5 minutes. The temperature at the peak top of the endothermic peak in the endothermic curve obtained during the second heating was measured as the melting point (Tm).

The acid value was measured by the following procedure according to JIS K0070-1966.
A phenolphthalein solution was prepared by dissolving 1.0 g of phenolphthalein in 90 ml of ethyl alcohol (95% by volume) and adding ion-exchanged water to 100 ml. 7 g of JIS special grade potassium hydroxide was dissolved in 5 ml of ion-exchanged water, and ethyl alcohol (95% by volume) was added to make 1 liter. A potassium hydroxide solution was prepared by placing the solution in an alkali resistant container for 3 days so as not to come into contact with carbon dioxide and then filtering it. The standardization was according to the description of JIS K0070-1966.

2.0 g of the crushed sample was precisely weighed in a 200 ml Erlenmeyer flask, 100 ml of a mixed solution of toluene / ethanol (2: 1) was added, and the mixture was dissolved over 5 hours. Next, an operation of adding a few drops of the phenolphthalein solution prepared as an indicator and titrating with the prepared potassium hydroxide solution was performed as a main test. The end point of the titration was when the light red color of the indicator continued for about 30 seconds.
Further, a blank test operation was performed in the same manner as the above main test except that the sample was not used (that is, only the mixed solution of toluene / ethanol (2: 1) was used).

The acid value was calculated by substituting the titration results obtained by the main test and the blank test into the following formula (1).
Formula (1) A = [(B−C) × f × 5.6] / S
A: Acid value (mgKOH / g)
B: Amount of potassium hydroxide solution added in blank test (ml)
C: Amount of potassium hydroxide solution added in this test (ml)
f: Factor of 0.1 mol / liter potassium hydroxide ethanol solution S: Mass of sample (g)

(Crystalline polyester resin (C2) to (C7))
In producing the crystalline polyester resin (C1), crystalline polyester resins (C2) to (C7) were obtained in the same manner except that the monomers were changed as shown in Table 3 below.

(Dispersion of crystalline polyester resin particles (c1))
72 parts by mass of the crystalline polyester resin (C1) was dissolved in 72 parts by mass of methyl ethyl ketone with stirring at 70 ° C. for 30 minutes. While stirring this solution, 2.5 parts by mass of a 25% by mass aqueous sodium hydroxide solution was added. Furthermore, an aqueous solution in which sodium polyoxyethylene lauryl ether sulfate was dissolved in 250 parts by mass of ion-exchanged water to a concentration of 1 mass% was added dropwise over 70 minutes.

While keeping the obtained emulsion at a temperature of 70 ° C., a diaphragm vacuum pump V-700 (manufactured by BUCHI) was used, and the mixture was stirred under reduced pressure of 15 kPa (150 mbar) for 3 hours to remove methyl ethyl ketone by distillation, A dispersion liquid (c1) of crystalline polyester resin (C1) particles was prepared.
The volume-based median diameter (d ₅₀ ) of the crystalline polyester resin (C1) particles in the dispersion liquid (c1) was 132 nm when measured with Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.).

(Dispersion of crystalline polyester resin particles (c2) to (c7))
In the preparation of the dispersion liquid (c1) of the crystalline polyester resin (C1) particles, the crystalline polyester resin (C1) was changed to the crystalline polyester resins (C2) to (C7) in the same manner as described above. Dispersions (c2) to (c7) of crystalline polyester resin (C2) to (C7) particles were prepared.

(Toner (1))
In a reaction vessel equipped with a thermometer, a pH meter, and a stirrer, 264.0 parts by mass (a1) of an aqueous dispersion of amorphous polyester resin particles (solid content), an aqueous dispersion of amorphous vinyl resin particles ( b1) 172.8 parts by mass (solid content conversion), crystalline polyester resin particle aqueous dispersion (c1) 43.2 parts by mass (solid content conversion), release agent particle dispersion (W) 38.4 parts by mass. Parts (as solid content), 28.8 parts by mass of the aqueous dispersion (Bk) of colorant particles (as solid content), 5.0 parts by mass of sodium lauryl sulfate, and 2000 parts by mass of ion-exchanged water. After 1.0% nitric acid was added at a temperature of 25 ° C. to adjust the pH to 3.0, the mixture was mixed and dispersed for 30 minutes with a homogenizer (Ultra Turrax T50 manufactured by IKA). While adding a shearing force by stirring, 30 parts by mass of a 10% aqueous solution of nitric acid of aluminum sulfate was dropped as a flocculant, and after the dropping was stirred for 10 minutes, the flocculant and the raw materials were sufficiently mixed.

  Next, while adjusting the rotation speed of the stirrer so that the slurry is sufficiently stirred, the temperature rising rate is 0.2 ° C / min up to a temperature of 40 ° C, and 0.05 ° C / min after the temperature exceeds 40 ° C. The temperature was raised at a heating rate of 10 and the particle size was measured every 10 minutes with a Multisizer 3 (aperture diameter: 50 μm, manufactured by Coulter). When the volume-based median diameter reached 6.0 μm, the temperature was maintained, the mixture was stirred for 30 minutes, and then the pH was adjusted to 8.5 using a 1% aqueous sodium hydroxide solution. Then, the temperature was raised to 85 ° C. at a heating rate of 1 ° C./minute while adjusting the pH to 8.5 at every 5 ° C., and 75.0 parts by mass of 20% EDTA aqueous solution was added. The aggregates were combined for 4 hours, cooled at a temperature lowering rate of 10 ° C./min, filtered, and thoroughly washed with ion-exchanged water. Then, it was dried at 40 ° C. to obtain toner particles having a volume-based median diameter of 6.0 μm.

  To 100 parts by mass of the obtained toner particles, 1.6 parts by mass of hydrophobic silica (number average primary particle size = 12 nm, hydrophobicity = 68) and hydrophobic titanium oxide (number average primary particle size = 20 nm, hydrophobicity degree) = 63) 0.6 part by mass was added and mixed for 20 minutes with a Henschel mixer (manufactured by Mitsui Miike Kakoki Co., Ltd.) at a rotary blade peripheral speed of 35 mm / sec, and a toner (1 having a volume-based median diameter of 6.0 μm) ) Got.

(Toner (2) to (17))
In the preparation of Toner (1), the amorphous polyester resin, the amorphous vinyl resin and the crystalline polyester resin in the toner were changed as shown in Table 4 below by changing the dispersion liquid used. In the same manner, toners (2) to (17) were produced.

(Developers (1) to (17))
To the toners (1) to (17), a ferrite carrier coated with a silicone resin and having a volume average particle diameter of 40 μm is added and mixed so that the toner particle concentration is 6% by mass, whereby the developer (1 )-(17) were produced respectively.

[Evaluation]
(Low temperature fixability under normal temperature and humidity environment)
In the copying machine bizhub PRO (registered trademark) C6501 (manufactured by Konica Minolta Co., Ltd.), the fixing device was modified so that the surface temperature of the fixing heat roller could be changed within the range of 100 to 200 ° C., and the development was performed. Agents (1) to (17) were loaded respectively. Outputs a solid image with a toner adhesion amount of 8 g / m ² on A4 size thick paper mondi Color Copy 350 g / m ² (manufactured by mondi) under the environment of normal temperature and humidity (temperature 20 ° C., humidity 50% RH). The fixing experiment described above was repeated while changing the set fixing temperature from 100 ° C. to 200 ° C. in increments of 5 ° C.

The printed matter obtained in the fixing experiment at each fixing temperature was folded by a folding machine so that a load was applied to the solid image, and compressed air of 0.35 MPa was blown. The folds were ranked according to the following evaluation criteria.
5: No creases at all 4: Partially peeled according to folds 3: Fine line-like peeling according to folds 2: Thick linear peeling according to folds 1: Followed folds Large peeling

Among the fixing experiments of rank 3 or higher, the fixing temperature in the fixing experiment having the lowest fixing temperature was set as the lower limit fixing temperature. From this lower limit fixing temperature, low-temperature fixability was rank-evaluated according to the following evaluation criteria, and rank 2 or higher was passed.
4: Lower limit fixing temperature is 140 ° C or lower 3: Lower limit fixing temperature is higher than 140 ° C and lower than 145 ° C 2: Lower limit fixing temperature is higher than 145 ° C and lower than 150 ° C 1: Lower limit fixing is higher than 150 ° C

(Low temperature fixability under high temperature environment)
Toners (1) to (17) were stored for 14 days in a thermostat at a temperature of 50 ° C. and a humidity of 50% RH. A developer was prepared in the same manner as above using the toner after storage, and the lower limit fixing temperature was determined under the same conditions (temperature 20 ° C., humidity 50% RH) as under normal temperature and normal humidity, and rank evaluation was performed. .

(Stability of low temperature fixability)
The lower limit fixing temperature in the normal temperature and normal humidity environment is the lower limit fixing temperature before high temperature storage, and the lower limit fixing temperature in the high temperature environment is the lower limit fixing temperature after high temperature storage. Therefore, the rank evaluation was performed, and the rank 2 or higher was regarded as passing.
4: The lower limit fixing temperature before and after high temperature storage is the same 3: The lower limit fixing temperature before and after high temperature storage exceeds 0 ° C and 5 ° C or less 2: The lower limit fixing temperature before and after high temperature storage exceeds 5 ° C and 10 ° C or less 1 : The lower limit of fixing temperature difference before and after high temperature storage exceeds 10 ° C

(Glossiness under normal temperature and humidity)
A commercially available multifunction machine bishub PRO C6501 (manufactured by Konica Minolta Co., Ltd.) was used as an image forming apparatus, and the developers (1) to (17) were loaded in this multifunction machine. In the environment of normal temperature and normal humidity (temperature 20 ° C., humidity 50% RH), the surface temperature of the heating member of the fixing device using the heat roller fixing method is 180 ° C., and the paper POD 128 g gloss coat (128 g / m ² ) (Oji Paper Co., Ltd.) A solid image having a toner adhesion amount of 4 g / m ² was formed on the above (manufactured), and its glossiness (°) was measured.
The glossiness was measured with a gloss meter Gloss Meter (manufactured by Murakami Color Engineering Laboratory Co., Ltd.) at an incident angle of 75 ° with a glass surface having a refractive index of 1.567 as a reference.

(Glossiness under high temperature)
Similar to the evaluation of the low temperature fixing property under the high temperature, the toners (1) to (17) stored for 14 days in a constant temperature bath at a temperature of 50 ° C. and a humidity of 50% RH were used, and the same as under the normal temperature and normal humidity. And the glossiness was measured.

(Gloss stability)
The glossiness under normal temperature and normal humidity is the glossiness before high temperature storage, and the glossiness under high temperature is the glossiness after high temperature storage, and the stability of glossiness is ranked according to the following evaluation criteria from the absolute value of each difference. However, a rank of 2 or higher was passed.
3: Absolute value of glossiness difference before and after high temperature storage is 5 ° or less 2: Absolute value of glossiness difference before and after high temperature storage exceeds 5 ° and 10 ° or less 1: Absolute value of glossiness difference before and after high temperature storage is Over 10 °

(Heat resistant storage)
0.5 g of the toner is taken in a 10 mL glass bottle having an inner diameter of 21 mm, the lid is closed, and 600 times under the environment of normal temperature and normal humidity (temperature 20 ° C., humidity 50% RH) with Tapdenser KYT-2000 (manufactured by Seishin Enterprise Co., Ltd.). After shaking, it was left for 2 hours in an environment of 57.5 ° C. and 35% RH with the lid removed. Next, the toner was placed on a 48-mesh (mesh opening 350 μm) sieve, being careful not to crush the toner aggregates, and set on a powder tester (manufactured by Hosokawa Micron Corporation). After fixing with a holding bar and a knob nut, adjusting the vibration strength to a feed width of 1 mm and applying vibration for 10 seconds, the toner aggregation rate (%) was calculated from the toner amount remaining on the sieve by the following formula.
Toner aggregation rate (%) = (mass of residual toner on the sieve (g) /0.5 (g)) × 100

From the toner aggregation rate, the heat-resistant storability was ranked according to the following evaluation criteria, and a rank of 3 or higher was passed. It should be noted that the smaller the toner aggregation rate, the higher the heat resistant storage stability.
4: Toner aggregation rate is less than 10% 3: Toner aggregation rate is 10% or more and less than 15% by weight 2: Toner aggregation rate is 15% or more and 20% by weight or less 1: Toner aggregation rate is more than 20%

Table 5 below shows the evaluation results.

  As shown in Table 5, the content of the crystalline polyester resin having a weight average molecular weight (Mw) in the range of 50,000 to 200,000 in the binder resin was 5 together with the amorphous polyester resin and the amorphous vinyl resin. Each of the toners (1) to (12) contained in the range of ˜30% by mass has excellent low-temperature fixability and heat-resistant storability, low temperature fixability even at high temperatures, and little fluctuation in glossiness, and stability. It turns out to be expensive.

Claims (6)

A toner for developing an electrostatic charge image containing toner particles,
The toner particles contain at least a binder resin,
The binder resin contains an amorphous polyester resin, an amorphous vinyl resin and a crystalline polyester resin,
The crystalline polyester resin is a polyester resin showing crystallinity among polyester resins obtained only by polycondensation of a carboxylic acid monomer having a valence of 2 or more and an alcohol monomer having a valence of 2 or more,
The weight average molecular weight (Mw) of the crystalline polyester resin is in the range of 80,000 to 150,000,
A toner for developing an electrostatic charge image, wherein the content of the crystalline polyester resin in the binder resin is in the range of 5 to 30% by mass.   The toner for developing an electrostatic charge image according to claim 1, wherein the content of the amorphous polyester resin in the binder resin is 60% by mass or more.   The electrostatic charge image developing toner according to claim 1 or 2, wherein a mass ratio of the amorphous vinyl resin and the crystalline polyester resin is within a range of 20:80 to 80:20. . The amorphous vinyl resin has a structure derived from a monomer having at least an acid group,
The content of the portion having a structure derived from the monomer having an acid group in the amorphous vinyl resin is in the range of 1 to 10% by mass. The toner for developing an electrostatic charge image according to any one of items 1 to 6 above.   The electrostatic charge image developing toner according to any one of claims 1 to 4, wherein the crystalline polyester resin has an acid value within a range of 10 to 25 mgKOH / g.   The electrostatic image developing toner according to any one of claims 1 to 5, wherein the crystalline polyester resin has a melting point in the range of 65 to 85 ° C.