Toner for developing electrostatic images and electrostatic image developers

Abstract

To provide a toner for electrostatic charge image development and an electrostatic charge image developer which have good low temperature fixation properties and hardly cause tacking.SOLUTION: A toner particle included in the toner for electrostatic charge image development contains an amorphous vinyl resin, an amorphous polyester resin, a crystalline polyester resin and an ester wax, wherein the crystalline polyester resin is a crystalline polyester resin obtained by polycondensation of a dicarboxylic acid having 9-14 carbon atoms with a dialcohol having 9-14 carbon atoms, the amorphous polyester resin is an amorphous polyester resin that includes a constitutional unit derived from a dicarboxylic acid having 9-14 carbon atoms or dialcohol having 9-14 carbon atoms, and wherein the sum total of the carbon atoms of the dicarboxylic acid and the carbon atoms of dialcohol is in the range of 18-24.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a toner for developing electrostatic images and an electrostatic image developer. More specifically, the present invention relates to a toner for developing electrostatic images which has good low-temperature fixability and is less likely to cause tacking. [Background technology]

[0002] In recent years, electrophotographic image forming apparatuses have been in demand for toners for developing electrostatic images (hereinafter simply referred to as "toners") that can be thermally fixed at low temperatures. Toners have been proposed that improve low-temperature fixability by adding crystalline substances or waxes with high plasticizing effects as fixing aids and lowering the melting temperature and melt viscosity of the binder resin (see, for example, Patent Document 1). While toners containing such fixing aids have good low-temperature fixability, the toner itself and the fixed image are vulnerable to thermal stress. In particular, when images with a large amount of toner adhesion are continuously printed, the images accumulate while retaining latent heat, which can cause a problem of image areas adhering to the paper or image areas adhering to each other, known as "tacking." This problem can occur.

[0003] Patent Document 2 proposes a toner containing a crystalline polyester resin, in which the top temperature of the exothermic peak and the half-width of the exothermic peak during cooling measured by differential scanning calorimetry (DSC) of the toner are within a certain range. Although this toner has a high crystallization temperature, it does not take into consideration the proportion of crystallized crystalline polyester resin and release agent added relative to their amounts. Even if the toner has a high crystallization temperature, if the proportion of crystallized crystalline polyester resin and release agent added is low, the resin layer will not solidify sufficiently, resulting in tacking, so there is room for improvement. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-045850 [Patent Document 2] Japanese Patent Application Publication No. 2018-087901 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in consideration of the above problems and circumstances, and the problem to be solved is to provide a toner for developing electrostatic images and an electrostatic image developer that have good low-temperature fixing properties and are less likely to cause tacking. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the present inventors have investigated the causes of the above-mentioned problems, and as a result, have found that when the toner particles contained in the toner for developing electrostatic images of the present invention contain an amorphous vinyl resin, an amorphous polyester resin, a crystalline polyester resin, and an ester wax, and the crystalline polyester resin is a crystalline polyester resin obtained by polycondensation of a dicarboxylic acid and a dialcohol having a carbon atom number within a specific range, and the amorphous polyester resin is an amorphous polyester resin containing a structural unit derived from a dicarboxylic acid or a dialcohol having a carbon atom number within the specific range, the toner has good low-temperature fixability and is less likely to cause tacking, thereby arriving at the present invention. That is, the above-mentioned problems of the present invention are solved by the following means.

[0007] 1. A toner for developing electrostatic images, comprising at least toner particles, the toner particles contain an amorphous vinyl resin, an amorphous polyester resin, a crystalline polyester resin, and an ester wax; the crystalline polyester resin contains at least one crystalline polyester resin A obtained by polycondensation of a dicarboxylic acid having at least 9 to 14 carbon atoms and a dialcohol having at least 9 to 14 carbon atoms; the amorphous polyester resin is an amorphous polyester resin containing a structural unit derived from a dicarboxylic acid having 9 to 14 carbon atoms or a dialcohol having 9 to 14 carbon atoms, The structural units contained in the amorphous polyester resin include a structural unit derived from the same dicarboxylic acid or dialcohol as a raw material monomer of the crystalline polyester resin A, and the total number of carbon atoms of the dicarboxylic acid and the dialcohol to be polycondensed to obtain the crystalline polyester resin A is within a range of 18 to 24; The amorphous polyester resin contains a structural unit derived from a dicarboxylic acid having 9 to 14 carbon atoms or a dialcohol having 9 to 14 carbon atoms. , relative to the total amount of the amorphous polyester resin 1. A toner for developing electrostatic images, comprising an amorphous polyester resin contained in an amount of 1 to 20 mol %.

[0008] 2. A crystalline polyester resin in which 50% by mass or more of the total amount of the crystalline polyester resin is obtained by polycondensation of the dicarboxylic acid having 9 to 14 carbon atoms and the dialcohol having 9 to 14 carbon atoms. A 2. The toner for developing electrostatic images according to claim 1, wherein:

[0009] 3. All of the crystalline polyester resins are obtained by polycondensation of the dicarboxylic acid having 9 to 14 carbon atoms and the dialcohol having 9 to 14 carbon atoms. A 3. The toner for developing electrostatic images according to claim 1 or 2, wherein:

[0010] 4. The toner for developing electrostatic images according to any one of items 1 to 3, wherein the acid value of the crystalline polyester resin is within the range of 20 to 30 mgKOH / g.

[0014] 5The crystalline polyester resin is a hybrid crystalline polyester resin in which a crystalline polyester polymer segment and a vinyl polymer segment having a styrene-derived structural unit are chemically bonded. 4 Item 1. The toner for developing electrostatic images according to any one of items 1 to 9.

[0015] 6 The amorphous polyester resin is a hybrid amorphous polyester resin in which an amorphous polyester polymer segment and a vinyl polymer segment having a styrene-derived structural unit are chemically bonded. 5 Item 1. The toner for developing electrostatic images according to any one of items 1 to 9.

[0016] 7 Item 1 to Item 3, characterized in that the cellulose further contains Fischer-Tropsch wax. 6 Item 1. The toner for developing electrostatic images according to any one of items 1 to 9.

[0017] 8 The content W of the amorphous polyester resin ap and the content W of the crystalline polyester resin cp Ratio of W ap / W cp The first to third items are characterized in that the value of is in the range of 0.5 to 1.5. 7 Item 1. The toner for developing electrostatic images according to any one of items 1 to 9.

[0018] 9 .Items 1 to 5 8 1. An electrostatic image developer comprising the toner for developing electrostatic images according to any one of claims 1 to 9. [Effects of the Invention]

[0019] The above-described means of the present invention can provide a toner for developing electrostatic images and an electrostatic image developer which have good low-temperature fixability and are less likely to cause tacking.

[0020] The mechanism by which the effects of the present invention are manifested or the mechanism of action is not clear, but is speculated as follows.

[0021] Tacking occurs when the crystalline substances (crystalline polyester resin and wax) in the toner do not fully crystallize before the high-temperature images are stacked after fixing, causing the viscosity of the resin layer to decrease, resulting in images adhering to each other. Therefore, tacking can be suppressed when the crystalline substances in the toner crystallize at high temperatures and at a high rate relative to the amount added after fixing.

[0022] The crystallization temperature and degree of crystallization after fixing can be controlled by the chain length (number of carbon atoms) of the dialcohol and dicarboxylic acid that make up the crystalline polyester resin. The larger the carbon number, the higher the crystallization temperature and the greater the rate of crystallization. However, at the same time, compatibility with the binder resin also deteriorates, so the viscosity of the binder resin does not decrease sufficiently during fixing, resulting in poor low-temperature fixability. Therefore, to solve this problem, it is necessary to facilitate crystallization without reducing the compatibility between the crystalline substance and the binder resin.

[0023] As in the present invention, by including an amorphous polyester resin having structural units similar to those constituting the crystalline polyester resin in the binder resin of the toner, compatibility with the crystalline polyester resin during fixing and ease of crystallization after fixing can both be achieved. This is thought to be because, during fixing, the crystalline polyester resin selectively dissolves in structural unit sites of the amorphous polyester resin similar to those of the crystalline polyester resin, reducing the viscosity of the binder resin, and further, after fixing, the selective compatibility results in a locally high concentration of the crystalline polyester resin, creating a state in which crystallization is likely to occur easily.

[0024] Furthermore, it was found that the effects of the present invention are particularly excellent when the chain lengths (number of carbon atoms) of the dialcohol and dicarboxylic acid constituting the crystalline polyester resin are both within the range of 9 to 14. This is thought to be because the uniformity of the ester group distribution makes crystallization easier. It was also found that if the total number of carbon atoms of the dialcohol and dicarboxylic acid used in the crystalline polyester resin is less than 18, tacking is likely to occur, and if it is more than 24, compatibility is poor and fixability deteriorates.

[0025] It is believed that these mechanisms of expression or action make it possible to provide a toner for developing electrostatic images that has good low-temperature fixability and is less likely to cause tacking. DETAILED DESCRIPTION OF THE INVENTION

[0026] The electrostatic image developing toner of the present invention is a toner for developing electrostatic images containing at least toner particles, the toner particles containing an amorphous vinyl resin, an amorphous polyester resin, a crystalline polyester resin, and an ester wax, the crystalline polyester resin being at least A crystalline polyester resin obtained by polycondensation of a dicarboxylic acid having 9 to 14 carbon atoms and a dialcohol having 9 to 14 carbon atoms. Contains one or more types of A the amorphous polyester resin contains a structural unit derived from a dicarboxylic acid having 9 to 14 carbon atoms or a dialcohol having 9 to 14 carbon atoms, the structural units contained in the amorphous polyester resin include structural units derived from the same dicarboxylic acid or dialcohol as raw material monomers of the crystalline polyester resin A, and, To obtain the crystalline polyester resin A, polycondensation is carried out. The total number of carbon atoms of the dicarboxylic acid and the dialcohol is in the range of 18 to 24. This feature is a technical feature common to or corresponding to the following embodiments.

[0027] In an embodiment of the electrostatic image developing toner of the present invention, 50% by mass or more of the total amount of the crystalline polyester resin is a crystalline polyester resin obtained by polycondensation of the dicarboxylic acid having 9 to 14 carbon atoms and the dialcohol having 9 to 14 carbon atoms. A is preferable from the viewpoint of achieving both low-temperature fixability and suppressing tacking.

[0028] In an embodiment of the electrostatic image developing toner of the present invention, all of the crystalline polyester resins are crystalline polyester resins obtained by polycondensation of the dicarboxylic acid having 9 to 14 carbon atoms and the dialcohol having 9 to 14 carbon atoms. A is preferable from the viewpoint of achieving both low-temperature fixability and suppressing tacking.

[0029] In an embodiment of the electrostatic image developing toner of the present invention, the acid value of the crystalline polyester resin is preferably within a range of 20 to 30 mgKOH / g from the viewpoint of low-temperature fixability and production stability.

[0030] In an embodiment of the toner for developing electrostatic images of the present invention, the amorphous polyester resin is preferably an amorphous polyester resin containing 1 to 20 mol % of structural units derived from a dicarboxylic acid having 9 to 14 carbon atoms or a dialcohol having 9 to 14 carbon atoms, from the viewpoint of achieving both low-temperature fixability and suppressing tacking.

[0031] In an embodiment of the toner for developing electrostatic images of the present invention, it is preferred that the number of carbon atoms of the dicarboxylic acid having 9 to 14 carbon atoms is the same as the number of carbon atoms of the dialcohol having 9 to 14 carbon atoms, from the viewpoint of achieving both low-temperature fixability and suppressing tacking.

[0032] In an embodiment of the toner for developing electrostatic images of the present invention, it is preferred that the dicarboxylic acid having 9 to 14 carbon atoms is sebacic acid and the dialcohol having 9 to 14 carbon atoms is 1,10-decanediol, from the viewpoint of achieving both low-temperature fixability and suppressing tacking.

[0033] In an embodiment of the toner for developing electrostatic images of the present invention, it is preferred from the viewpoint of low-temperature fixability that the crystalline polyester resin is a hybrid crystalline polyester resin in which a crystalline polyester polymer segment and a vinyl polymer segment having a styrene-derived structural unit are chemically bonded.

[0034] In an embodiment of the toner for developing electrostatic images of the present invention, it is preferable from the viewpoint of low-temperature fixability that the amorphous polyester resin is a hybrid amorphous polyester resin in which an amorphous polyester polymer segment and a vinyl polymer segment having a styrene-derived structural unit are chemically bonded.

[0035] In an embodiment of the toner for developing electrostatic images of the present invention, the content W of the amorphous polyester resin is ap and the content W of the crystalline polyester resin cp Ratio of W ap / W cp It is preferable that the value of is within the range of 0.5 to 1.5 from the viewpoint of achieving both low-temperature fixability and suppressing tacking.

[0036] In an embodiment of the toner for developing electrostatic images of the present invention, it is preferred from the viewpoint of suppressing tacking that it further contains a Fischer-Tropsch wax.

[0037] The electrostatic image developer of the present invention (hereinafter also simply referred to as "developer") is characterized by containing the electrostatic image developing toner of the present invention.

[0038] The present invention, its components, and embodiments for carrying out the present invention will be described in detail below. In this application, the symbol "to" is used to mean that the numerical values ​​before and after it are included as lower and upper limits.

[0039] <<Outline of toner for developing electrostatic images>> The electrostatic image developing toner of the present invention is a toner for developing electrostatic images containing at least toner particles, the toner particles containing an amorphous vinyl resin, an amorphous polyester resin, a crystalline polyester resin, and an ester wax, the crystalline polyester resin being at least A crystalline polyester resin obtained by polycondensation of a dicarboxylic acid having 9 to 14 carbon atoms and a dialcohol having 9 to 14 carbon atoms. Contains one or more types of A the amorphous polyester resin contains a structural unit derived from a dicarboxylic acid having 9 to 14 carbon atoms or a dialcohol having 9 to 14 carbon atoms, the structural units contained in the amorphous polyester resin include structural units derived from the same dicarboxylic acid or dialcohol as raw material monomers of the crystalline polyester resin A, and, To obtain the crystalline polyester resin A, polycondensation is carried out. The total number of carbon atoms of the dicarboxylic acid and the dialcohol is in the range of 18 to 24.

[0040] If the total number of carbon atoms in the dialcohol and dicarboxylic acid used in the crystalline polyester resin is less than 18, tacking is likely to occur, whereas if it is more than 24, compatibility is poor and fixability deteriorates. Furthermore, the smaller the difference in the number of carbon atoms between the dialcohol and dicarboxylic acid, the more uniform the distribution of ester groups becomes and the easier crystallization becomes. Therefore, tacking can be suppressed by ensuring that the number of carbon atoms in each is within the range of 9 to 14.

[0041] In the present invention, the term "toner for developing electrostatic images" refers to toner base particles or an aggregate of toner particles. Here, the "toner particles" preferably refer to toner base particles to which an external additive has been added, but the toner base particles can also be used as they are as toner particles. In the present invention, there is no need to particularly distinguish between toner base particles, toner particles, and toner. If not, it is simply called "toner."

[0042] <Binder resin> The toner particles of the present invention contain, as binder resins, an amorphous vinyl resin, an amorphous polyester resin, and a crystalline polyester resin.

[0043] The content of the binder resin in the toner particles is preferably 70 to 95% by mass with respect to the total amount of the toner particles.

[0044] The content of the amorphous vinyl resin in the binder resin is preferably 10 to 90% by mass with respect to the total amount of the binder resin.

[0045] The content of the amorphous polyester resin in the binder resin is preferably 10 to 90% by mass with respect to the total amount of the binder resin.

[0046] The content of the crystalline polyester resin in the binder resin is preferably 1 to 20% by mass relative to the total amount of the binder resin.

[0047] Amorphous polyester resin content in toner particles W ap and the content of crystalline polyester resin W cp Ratio of W ap / W cp It is preferable that the value of is within the range of 0.5 to 1.5 from the viewpoint of achieving both low-temperature fixability and suppressing tacking.

[0048] <Crystalline polyester resin> The crystalline polyester resin refers to a polyester resin that exhibits crystallinity and is obtained by a polycondensation reaction between a polycarboxylic acid and a polyhydric alcohol.

[0049] "Exhibiting crystallinity" means that the endothermic curve obtained by DSC has a clear endothermic peak rather than a stepwise change at the melting point, i.e., when the temperature is increased. A clear endothermic peak is a peak with a half-width of 15°C or less in the endothermic curve when the temperature is increased at a rate of 10°C / min.

[0050] (Crystalline polyester resin A) The crystalline polyester resin according to the present invention is a crystalline polyester resin obtained by polycondensation of a dicarboxylic acid having 9 to 14 carbon atoms and a dialcohol having 9 to 14 carbon atoms, characterized in that the total number of carbon atoms of the dicarboxylic acid and the dialcohol is in the range of 18 to 24. Hereinafter, a crystalline polyester resin satisfying this condition will be referred to as "crystalline polyester resin A." Note that crystalline polyester resin A may use, as raw material monomers, components other than the dicarboxylic acid and dialcohol having 9 to 14 carbon atoms.

[0051] Furthermore, it is preferable that the total number of carbon atoms of the dialcohol and dicarboxylic acid used in the crystalline polyester resin A is within the range of 18 to 22, in terms of improving low-temperature fixability.

[0052] Of the total amount of crystalline polyester resins contained in the toner particles according to the present invention, the proportion of crystalline polyester resin A is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more. Furthermore, of the total amount of crystalline polyester resins contained in the toner particles according to the present invention, it is most preferable that all of the crystalline polyester resins are crystalline polyester resin A. The higher the proportion of crystalline polyester resin A, the greater the effect of the present invention.

[0053] From the viewpoint of achieving both low-temperature fixability and suppression of tacking, the crystalline polyester resin A preferably contains, in the polycarboxylic acid raw material monomer, a dicarboxylic acid having 9 to 14 carbon atoms in a proportion as high as possible, specifically, 90 mol % or more. Also, in the polyhydric alcohol raw material monomer, the crystalline polyester resin A preferably contains, in the polycarboxylic acid raw material monomer, a dicarboxylic acid having 9 to 14 carbon atoms in a proportion as high as possible, specifically, 90 mol % or more.

[0054] As the dicarboxylic acid having 9 to 14 carbon atoms, the following straight-chain dicarboxylic acids are preferred. 9 carbon atoms: Azelaic acid (nonanedioic acid, 1,7-heptanedicarboxylic acid) 10 carbon atoms: Sebacic acid (decanedioic acid, 1,8-octanedicarboxylic acid) Carbon atoms: 11: Undecanedionic acid (undecane diacid, 1,9-nonanedicarboxylic acid) 12 carbon atoms: Dodecanedioic acid (dodecanedioic acid, 1,10-decanedicarboxylic acid) 13 carbon atoms: Tridecanedioic acid (tridecanedioic acid, 1,11-undecanedicarboxylic acid) 14 carbon atoms: tetradecanedioic acid (tetradecanedioic acid, 1,12-dodecanedicarboxylic acid)

[0055] As the dialcohol having 9 to 14 carbon atoms, the following straight-chain dialcohols are preferred. Carbon number 9: 1,9-nonanediol Carbon number 10: 1,10-decanediol Carbon number 11: 1,11-undecanediol Carbon number 12: 1,12-dodecanediol Carbon number 13: 1,13-tridecanediol Carbon number 14: 1,14-tetradecanediol

[0056] From the viewpoint of achieving both low-temperature fixability and suppression of tacking, the crystalline polyester resin A preferably contains, among the polycarboxylic acids that are raw material monomers to be polycondensed, a higher proportion of dicarboxylic acids having 9 to 14 carbon atoms. Furthermore, it is preferable that, in the crystalline polyester resin, 90 mol % or more of the polyhydric alcohols that are raw material monomers to be polycondensed are dicarboxylic acids having 9 to 14 carbon atoms.

[0057] From the viewpoint of achieving both low-temperature fixability and suppressing tacking, the crystalline polyester resin A preferably has the same number of carbon atoms in the dicarboxylic acid and the dialcohol used as raw monomers to be polymerized. Furthermore, the crystalline polyester resin A is particularly preferably a crystalline polyester resin obtained by polycondensation of sebacic acid and 1,10-decanediol.

[0058] (Other crystalline polyester resins) With respect to the crystalline polyester resins other than the crystalline polyester resin A that may be contained in the toner particles according to the present invention, there are no particular limitations on the raw material monomers to be polycondensed.

[0059] Examples of polycarboxylic acids that can be used include aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, n-dodecylsuccinic acid, nonanedicarboxylic acid, decanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, and tetradecanedicarboxylic acid, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid, and trivalent or higher polycarboxylic acids such as trimellitic acid and pyromellitic acid, as well as anhydrides of these carboxylic acid compounds and alkyl esters having 1 to 3 carbon atoms. These may be used alone or in combination of two or more.

[0060] Examples of polyhydric alcohols that can be used include aliphatic diols such as 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, dodecanediol, neopentyl glycol, and 1,4-butenediol, and trihydric or higher polyhydric alcohols such as glycerin, pentaerythritol, trimethylolpropane, and sorbitol. These may be used alone or in combination of two or more.

[0061] (Method for synthesizing crystalline polyester resin) The method for synthesizing the crystalline polyester resin is not particularly limited, and the resin can be synthesized by polycondensing (esterifying) the polyhydric alcohol component and the polycarboxylic acid component using a known esterification catalyst.

[0062] The ratio of the polyhydric alcohol component to the polycarboxylic acid component used is preferably such that the equivalent ratio of the hydroxyl groups of the polyhydric alcohol component to the carboxyl groups of the polycarboxylic acid component is within a range of 1.5 / 1 to 1 / 1.5, more preferably within a range of 1.2 / 1 to 1 / 1.2.

[0063] Catalysts that can be used in the synthesis of crystalline polyester resins 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, phosphorous compounds, phosphate compounds, and amine compounds. Examples of tin compounds include dibutyltin oxide, tin octoate, tin dioctoate, and salts thereof. Examples of titanium compounds include titanium alkoxides such as tetra-n-butyl titanate, tetraisopropyl titanate, tetramethyl titanate, and tetrastearyl titanate, titanium acylates such as polyhydroxytitanium stearate, and titanium chelates such as titanium tetraacetylacetonate, titanium lactate, and titanium triethanolamine. Examples of germanium compounds include germanium dioxide. Examples of aluminum compounds include oxides such as polyaluminum hydroxide, aluminum alkoxides, and tributylaluminate. These compounds may be used alone or in combination of two or more.

[0064] The polymerization temperature and polymerization time are not particularly limited, and the pressure in the reaction system may be reduced during the polymerization, if necessary.

[0065] (Acid value of crystalline polyester resin) The acid value of the crystalline polyester resin in the present invention is preferably within the range of 20 to 30 mgKOH / g from the viewpoint of low-temperature fixability and production stability.

[0066] The acid value is the mass of potassium hydroxide (KOH) required to neutralize the acid contained in 1 g of a sample, expressed in mg. The acid value of a resin is measured according to the following procedure in accordance with JIS K0070-1966.

[0067] [Reagent preparation] Dissolve 1.0 g of phenolphthalein in 90 mL of ethyl alcohol (95% by volume) and add ion-exchanged water to make 100 mL to prepare a phenolphthalein solution. Dissolve 7 g of JIS special grade potassium hydroxide in 5 mL of ion-exchanged water and add ethyl alcohol (95% by volume) to make 1 liter. Place in an alkali-resistant container to avoid contact with carbon dioxide and leave for 3 days, then filter to prepare a potassium hydroxide solution. Standardization follows the instructions in JIS K0070-1966.

[0068] [Actual exam] Accurately weigh 2.0 g of the crushed sample into a 200 mL Erlenmeyer flask, add 100 mL of a toluene / ethanol (2:1) mixture, and dissolve for 5 hours. Next, add a few drops of the prepared phenolphthalein solution as an indicator, and titrate with the prepared potassium hydroxide solution. The endpoint of the titration is when the indicator's light red color lasts for approximately 30 seconds.

[0069] [Blank test] The same procedure as in the main test above is carried out, except that no sample is used (i.e., only the toluene / ethanol (2:1) mixed solution is used).

[0070] [calculation] The titration results of the main test and the blank test are substituted into the following formula (1) to calculate the acid value. Formula (1) A=[(BC)×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 during this test (mL) f: Factor of 0.1 mol / L potassium hydroxide ethanol solution S: mass of sample (g)

[0071] (Weight average molecular weight of crystalline polyester resin) The weight average molecular weight of the crystalline polyester resin is preferably within the range of 1,000 to 29,000. When the molecular weight is 1,000 or more, the crystalline polyester resin is not excessively miscible after melting, crystallization proceeds, and tacking suppression is excellent.When the molecular weight is 29,000 or less, the crystalline polyester resin is easily miscible when melting, and low-temperature fixability is excellent.

[0072] The weight average molecular weight of the crystalline polyester resin is measured by the following method. Gel permeation chromatography (HLC-8320GPC: Tosoh Corporation) Measurement can be performed using a column consisting of one "TSKgel guard column SuperHZ-L" and three "TSKgel SuperHZM-M" columns (all manufactured by Tosoh Corporation) connected together. The column (TSK-) was stabilized at 40°C, and tetrahydrofuran (THF) was applied as a carrier solvent at a flow rate of 0.35 mL / min. A THF sample solution containing the resin sample, adjusted to a sample concentration of 1 mg / mL, was treated with a roll mill at room temperature for 10 minutes, and then filtered through a 0.2 μm pore membrane filter to obtain a sample solution. 10 μL of this sample solution was injected into the instrument along with the carrier solvent and detected using a refractive index detector (RI detector). The molecular weight distribution of the measured sample is calculated based on a calibration curve created using a polystyrene standard sample with a monodisperse molecular weight distribution. The calibration curve is created from 10 samples of "Polystylene Standard Sample TSK Standard" manufactured by Tosoh Corporation: "A-500," "F-1," "F-10," "F-80," "F-380," "A-2500," "F-4," "F-40," "F-128," and "F-700." The data collection interval for sample analysis is 300 ms.

[0073] The weight-average molecular weight of the crystalline polyester resin can be calculated by the above-mentioned measurement method after separating the crystalline polyester resin and the release agent in the toner as follows. First, the toner is dispersed in ethanol, which is a poor solvent for the toner, and the temperature is raised to a temperature above the melting points of the crystalline polyester resin and the wax. At this time, pressure may be applied if necessary. At this point, the crystalline polyester resin and the wax, which have exceeded their melting points, are melted. Then, a mixture of the crystalline polyester resin and the wax can be extracted from the toner by solid-liquid separation. The crystalline polyester resin and the wax can be separated by classifying this mixture according to molecular weight.

[0074] (Melting point of crystalline polyester resin) The melting point (Tm) of the crystalline polyester resin is preferably in the range of 55 to 90°C, more preferably 70 to 85°C, from the viewpoint of obtaining sufficient low-temperature fixability and excellent hot offset resistance. The melting point of the crystalline polyester resin can be controlled by the resin composition.

[0075] The melting point (Tm) is the temperature at the top of the endothermic peak, and can be measured by DSC. Specifically, the sample was sealed in an aluminum pan (KIT NO. B0143013) and placed in the sample holder of a thermal analyzer, Diamond DSC (PerkinElmer). The temperature was then cycled through a series of cycles: heating, cooling, and heating. The first heating cycle was from room temperature (25°C), and the second heating cycle was from 0°C. The temperature was increased to 150°C at a rate of 10°C / min and held at 150°C for 5 minutes. The cooling cycle was performed by decreasing the temperature from 150°C to 0°C at a rate of 10°C / min and holding at 0°C for 5 minutes. The melting point was determined as the temperature at the top of the endothermic peak in the endothermic curve obtained during the second heating cycle.

[0076] (Hybrid crystalline polyester resin) The crystalline polyester resin A contained in the toner particles according to the present invention is preferably a hybrid crystalline polyester resin in which a crystalline polyester polymer segment and an amorphous polymer segment are chemically bonded, from the viewpoint of low-temperature fixability. It is particularly preferred that the amorphous polymer segment is a vinyl polymer segment having a structural unit derived from styrene.

[0077] The term "crystalline polyester polymer segment" refers to a portion derived from a crystalline polyester resin. That is, it refers to a molecular chain having the same chemical structure as the molecular chain constituting the aforementioned crystalline polyester resin. The term "amorphous polymer segment" refers to a portion derived from an amorphous resin. That is, it refers to a molecular chain having the same chemical structure as the molecular chain constituting the amorphous resin.

[0078] The chemically bonded structure is not particularly limited, and may be a block copolymer or a graft copolymer. It is preferable that the crystalline polyester polymerized segment is grafted to the amorphous polymerized segment as the main chain. That is, the hybrid crystalline polyester resin is preferably a graft copolymer having the amorphous polymerized segment as the main chain and the crystalline polyester polymerized segment as the side chain.

[0079] The crystalline polyester polymer segment is the same as the crystalline polyester resin described above, and is a portion derived from the polyester resin obtained by the polycondensation reaction of the polycarboxylic acid and the polyhydric alcohol described above. The crystalline polyester polymer segment can be synthesized from the polycarboxylic acid and the polyhydric alcohol in the same manner as the crystalline polyester resin described above.

[0080] The content of the crystalline polyester polymer segment is preferably 80% by mass or more and 98% by mass or less, and more preferably 90% by mass or more and 95% by mass or less, based on the total amount of the hybrid crystalline polyester resin. By setting the content within this range, sufficient crystallinity can be imparted to the hybrid crystalline polyester resin.

[0081] The amorphous polymer segment is preferably composed of the same type of resin as the amorphous resin (e.g., amorphous vinyl resin, amorphous polyester resin) contained in the toner particles as the binder resin, from the viewpoint of increasing affinity with the binder resin and improving the uniformity of toner charging. By adopting such a configuration, the affinity between the hybrid crystalline polyester resin and the amorphous resin is further improved. "Same type of resin" means resins having characteristic chemical bonds in the repeating units.

[0082] The "characteristic chemical bonds" are based on the "polymer classification" listed in the National Institute for Materials Science (NIMS) Materials Database (http: / / polymer.nims.go.jp / PoLyInfo / guide / jp / term_polymer.html). Specifically, the chemical bonds that make up polymers classified into 22 types, including polyacrylic, polyamide, polyanhydride, polycarbonate, polydienes, polyesters, polyhaloolefins, polyimides, polyimines, polyketones, polyolefins, polyethers, polyphenylenes, polyphosphazenes, polysiloxanes, polystyrenes, polysulfides, polysulfones, polyurethanes, polyureas, polyvinyls, and other polymers, are called "characteristic chemical bonds."

[0083] Furthermore, when the resin is a copolymer, "same type of resin" refers to resins that share a characteristic chemical bond when the monomer species having the above-mentioned chemical bond are used as constituent units in the chemical structures of the multiple monomer species that make up the copolymer. Therefore, even if the properties exhibited by the resins themselves are different from each other or the molar ratios of the monomer species that make up the copolymer are different from each other, they are considered to be the same type of resin as long as they share the characteristic chemical bond.

[0084] For example, a resin (or polymerized segment) formed from styrene, butyl acrylate, and acrylic acid and a resin (or polymerized segment) formed from styrene, butyl acrylate, and methacrylic acid have at least a chemical bond constituting polyacrylic, and therefore, they are the same type of resin. Further, for example, a resin (or polymerized segment) formed from styrene, butyl acrylate, and acrylic acid and a resin (or polymerized segment) formed from styrene, butyl acrylate, acrylic acid, terephthalic acid, and fumaric acid have at least a chemical bond constituting polyacrylic as a mutually shared chemical bond. Therefore, they are the same type of resin.

[0085] The amorphous polymerized segment preferably further contains an amphoteric compound as a monomer, from the viewpoint of introducing a chemical bonding site with the crystalline polyester polymerized segment into the amorphous polymerized segment. The content of the structural unit derived from the amphoteric compound in the amorphous polymerized segment is preferably 0.5% by mass or more and 20% by mass or less.

[0086] The "amphoteric compound" in the present invention is a monomer that bonds a crystalline polyester polymerized segment and an amorphous polymerized segment, and has, in its molecule, a substituent such as a hydroxy group, a carboxy group, an epoxy group, a primary amino group, or a secondary amino group that can react with the crystalline polyester polymerized segment, and an ethylenically unsaturated group that can react with the amorphous polymerized segment. Among these, vinyl carboxylic acids having a hydroxy group or a carboxy group and an ethylenically unsaturated group are preferred.

[0087] Examples of amphoteric compounds that can be used include (meth)acrylic acid, fumaric acid, and maleic acid, and hydroxyalkyl (having 1 to 3 carbon atoms) esters of these acids may also be used. From the viewpoint of reactivity, acrylic acid, methacrylic acid, and fumaric acid are preferred.

[0088] From the viewpoint of imparting sufficient crystallinity to the hybrid crystalline polyester resin, the content of the amorphous polymerized segment in the hybrid crystalline polyester resin is preferably 2% by mass or more and 20% by mass or less, more preferably 3% by mass or more and 15% by mass or less, even more preferably 5% by mass or more and 10% by mass or less, and particularly preferably 7% by mass or more and 9% by mass or less.

[0089] The resin component constituting the amorphous polymerized segment is not particularly limited, and examples thereof include a vinyl polymerized segment, a urethane polymerized segment, a urea polymerized segment, etc. Among these, a vinyl polymerized segment is preferred because it is easy to control the thermoplasticity.

[0090] The vinyl polymerized segment is not particularly limited as long as it is a polymerized vinyl compound, and examples thereof include an acrylate polymerized segment, a styrene-acrylate polymerized segment, an ethylene-vinyl acetate polymerized segment, etc. These may be used alone or in combination of two or more.

[0091] Among the vinyl polymer segments, those having a styrene-derived structural unit are preferred in consideration of plasticity during thermal fixation. Hereinafter, a styrene-acrylic polymer segment will be described as an amorphous polymer segment having a styrene-derived structural unit.

[0092] The styrene-acrylic polymerization segment is formed by addition polymerization of at least a styrene monomer and a (meth)acrylic acid ester monomer. The styrene monomer referred to here includes not only styrene represented by the structural formula CH2=CH-C6H5, but also those having a structure in which a known side chain or functional group is present in the styrene structure. The (meth)acrylic acid ester monomer referred to here includes not only acrylic acid ester compounds represented by CH2=CHCOOR (R is an alkyl group) and methacrylic acid ester compounds, but also ester compounds having a known side chain or functional group in the structure of acrylic acid ester derivatives, methacrylic acid ester derivatives, etc.

[0093] Specific examples of styrene monomers and (meth)acrylic acid ester monomers that can form styrene-acrylic polymerized segments are shown below, but those that can be used to form the styrene-acrylic polymerized segments used in the present invention are not limited to the following.

[0094] Specific examples of styrene monomers include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, etc. These styrene monomers can be used alone or in combination of two or more.

[0095] Specific examples of (meth)acrylic acid ester monomers include acrylic acid ester monomers such as methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, and phenyl acrylate; and methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, and dimethylaminoethyl methacrylate. Among these, it is preferable to use long-chain acrylic acid ester monomers. Specifically, methyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate are preferred.

[0096] The constituent components (chemical structure) and content of each segment in the hybrid crystalline polyester resin (or toner) can be identified by using known analytical methods such as nuclear magnetic resonance (NMR) measurement and methylation reaction pyrolysis gas chromatography / mass spectrometry (Py-GC / MS).

[0097] The method for synthesizing the hybrid crystalline polyester resin is not particularly limited as long as it is a method capable of forming a polymer having a structure in which the above-mentioned crystalline polyester polymerized segment and the amorphous polymerized segment are chemically bonded. Specific methods for synthesizing the hybrid crystalline polyester resin include, for example, the following first to third synthesis methods.

[0098] [First synthesis method] The first synthesis method is a method of synthesizing a hybrid crystalline polyester resin by carrying out a polymerization reaction to synthesize a crystalline polyester polymer segment in the presence of a previously synthesized amorphous polymer segment.

[0099] [Second synthesis method] The second synthesis method is a method in which a crystalline polyester polymer segment and an amorphous polymer segment are formed in advance, and then these are bonded to synthesize a hybrid crystalline polyester resin.

[0100] [Third synthesis method] The third synthesis method is a method of synthesizing a hybrid crystalline polyester resin by carrying out a polymerization reaction to synthesize an amorphous polymer segment in the presence of a crystalline polyester polymer segment.

[0101] Among the first to third synthesis methods, the first synthesis method is preferred because it is easy to synthesize a hybrid crystalline polyester resin having a structure in which a crystalline polyester polymer chain (crystalline polyester resin chain) is grafted to an amorphous polymer chain (amorphous resin chain) and because it simplifies the production process. The first production method forms an amorphous polymer segment beforehand and then bonds the crystalline polyester polymer segment, which makes it easy to achieve uniform orientation of the crystalline polyester polymer segment. Therefore, it is preferred from the viewpoint of reliably synthesizing a hybrid crystalline polyester resin suitable for the toner.

[0102] <Amorphous polyester resin> The amorphous polyester resin refers to a polyester resin that exhibits amorphous properties and is obtained by a polycondensation reaction between a polycarboxylic acid and a polyhydric alcohol.

[0103] "Exhibiting amorphousness" means that the material has a glass transition point (Tg) in an endothermic curve obtained by differential scanning calorimetry (DSC), but does not have a melting point, i.e., a clear endothermic peak, when heated. A clear endothermic peak is an endothermic peak with a half-width of 15°C or less in an endothermic curve when heated at a heating rate of 10°C / min.

[0104] The toner particles according to the present invention are characterized by containing an amorphous polyester resin containing a structural unit derived from a dicarboxylic acid having 9 to 14 carbon atoms or a dialcohol having 9 to 14 carbon atoms. This makes it possible to achieve both compatibility with the crystalline polyester resin during fixing and ease of crystallization after fixing.

[0105] Furthermore, from the viewpoint of achieving both low-temperature fixability and suppressing tacking, it is preferable that the toner particles contain structural units derived from dicarboxylic acids having 9 to 14 carbon atoms or dialcohols having 9 to 14 carbon atoms in an amount of 1 to 20 mol %, more preferably 4 to 16 mol %, relative to the total amount of amorphous polyester resin contained in the toner particles.

[0106] From the viewpoint of the effects of the present invention, the structural units derived from a dicarboxylic acid having 9 to 14 carbon atoms or a dialcohol having 9 to 14 carbon atoms contained in the amorphous polyester resin are preferably structural units derived from the same dicarboxylic acid or dialcohol as the raw material monomers of the crystalline polyester resin A. For example, when the raw material monomers of the crystalline polyester resin A are sebacic acid and 1,10-decanediol, the amorphous polyester resin preferably contains structural units derived from at least either sebacic acid or 1,10-decanediol.

[0107] Examples of polycarboxylic acids other than dicarboxylic acids from which the structural units are derived include phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, naphthalene-2,6-dicarboxylic acid, malonic acid, mesaconic acid, dimethyl isophthalate, fumaric acid, and dodecenylsuccinic acid.

[0108] Examples of polyhydric alcohols other than dicarboxylic acids from which the structural units are derived include ethylene glycol, propylene glycol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, ethylene oxide adduct of bisphenol A (BPA-EO), propylene oxide adduct of bisphenol A (BPA-PO), glycerin, sorbitol, 1,4-sorbitan, and trimethylolpropane.

[0109] (Method for synthesizing amorphous polyester resin) The method for synthesizing the amorphous polyester resin is not particularly limited, and the resin can be synthesized by polycondensing (esterifying) the polyhydric alcohol component and the polycarboxylic acid component using a known esterification catalyst such as those described above.

[0110] The polymerization temperature and polymerization time are not particularly limited, and the pressure in the reaction system may be reduced during the polymerization, if necessary.

[0111] (Weight average molecular weight of amorphous polyester resin) The weight average molecular weight (Mw) of the amorphous polyester resin is preferably within the range of 10,000 to 100,000. The weight average molecular weight of the amorphous polyester resin can be measured in the same manner as the weight average molecular weight of the crystalline polyester resin described above.

[0112] (Glass transition temperature of amorphous polyester resin) The glass transition point (Tg) of the amorphous polyester resin is preferably within the range of 25 to 60°C from the viewpoint of achieving both sufficient low-temperature fixability and heat-resistant storage stability.

[0113] The glass transition temperature (Tg) can be measured using a differential scanning calorimeter, such as a Diamond DSC (PerkinElmer). Specifically, 3.0 mg of sample is sealed in an aluminum pan and the temperature is changed in the following order: heating, cooling, and heating. The first heating was from room temperature (25°C), and the second heating was from 0°C. The temperature was increased to 200°C at a rate of 10°C / min, and then held at 150°C for 5 minutes. The cooling was performed by decreasing the temperature from 200°C to 0°C at a rate of 10°C / min and holding at 0°C for 5 minutes. The baseline shift in the measurement curve obtained during the second heating was observed, and the intersection of the extension of the baseline before the shift and the tangent line showing the maximum slope of the shifted baseline was taken as the glass transition temperature (Tg). An empty aluminum pan was used as a reference.

[0114] (Hybrid amorphous polyester resin) From the viewpoint of low-temperature fixability, the amorphous polyester resin contained in the toner particles according to the present invention is preferably a hybrid crystalline polyester resin in which an amorphous polyester polymer segment and an amorphous polymer segment other than the amorphous polyester are chemically bonded. It is particularly preferred that the amorphous polymer segment other than the amorphous polyester is a vinyl polymer segment having a structural unit derived from styrene.

[0115] The amorphous polyester polymer segment refers to a portion derived from an amorphous polyester resin, that is, a molecular chain having the same chemical structure as the molecular chain constituting the amorphous polyester resin described above.

[0116] The content of the amorphous polyester polymer segment is preferably 50 to 99.9% by mass, more preferably 70 to 95% by mass, based on the total amount of the hybrid amorphous polyester resin. By setting the content within this range, it is possible to achieve lower temperature fixation while maintaining heat resistance, and it is possible to achieve a balanced affinity with the amorphous vinyl resin.

[0117] Other aspects of the hybrid amorphous polyester resin (constituent components, synthesis method, etc.) are the same as those of the hybrid crystalline polyester resin described above, except that the crystalline polyester polymerized segment and the amorphous polyester polymerized segment are different.

[0118] <Amorphous vinyl resin> The amorphous vinyl resin refers to a polymer of a monomer having a vinyl group (hereinafter referred to as a vinyl monomer) that exhibits amorphous properties.

[0119] Examples of vinyl resins that can be used include styrene-acrylic resins, styrene resins, and acrylic resins, and among these, styrene-acrylic resins are preferred because of their excellent heat resistance.

[0120] Usable vinyl monomers include the following, and one of these may be used alone or two or more may be used in combination.

[0121] (1) Styrene-based monomers Monomers having a styrene structure, such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, and derivatives thereof (2) (Meth)acrylic acid ester monomers Monomers having a (meth)acrylic group, such as methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isopropyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, stearyl (meth)acrylate, lauryl (meth)acrylate, phenyl (meth)acrylate, diethylaminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, and derivatives thereof. (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, etc. (7) Other Vinyl compounds such as vinylnaphthalene and vinylpyridine, acrylic acid derivatives such as acrylonitrile, methacrylonitrile, and acrylamide, and methacrylic acid derivatives, etc.

[0122] As the vinyl monomer, it is preferable to use a monomer having an ionically dissociable group such as a carboxy group, a sulfonic acid group, or a phosphoric acid group, since this makes it easier to control the affinity with the crystalline resin. 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 styrene sulfonic acid, allyl sulfosuccinic acid, and 2-acrylamido-2-methylpropane sulfonic acid. Examples of the monomer having a phosphoric acid group include acidophosphooxyethyl methacrylate.

[0123] Furthermore, a polymer having a crosslinked structure can be obtained by using a polyfunctional vinyl as the vinyl monomer. Examples of 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, and neopentyl glycol diacrylate.

[0124] The preferred weight average molecular weight (Mw) and glass transition temperature (Tg) of the amorphous vinyl resin are the same as those of the amorphous polyester resin described above.

[0125] <Method for analyzing resin composition> The composition of each resin contained in the toner particles can be analyzed by, for example, pyrolysis gas chromatography mass spectrometry (GC / MS). Specifically, the amount can be determined by the standard addition method using a column and a detector that have been confirmed to be capable of detecting a monomer having a specific structure.

[0126] An example of detailed pyrolysis conditions and GC / MS measurement conditions is shown below. (Pyrolysis conditions) Measurement device: PY-2020iD (Frontier Labs) Measurement mass: 0.1 mg Heating temperature: 550℃ Heating time: 0.5 minutes (GC / MS measurement conditions) Measuring device: QP2010 manufactured by Shimadzu Corporation Column: UltraALLOY-5 (inner diameter: 0.25 mm, length: 30 m, thickness: 0.25 μm, manufactured by Frontier Labs) Temperature range: 40℃ to 320℃ (maintain at 320℃) Heating rate: 20°C / min

[0127] <Release agent> The toner particles according to the present invention are characterized by containing an ester wax as a release agent, which can suppress tacking. The toner particles according to the present invention may contain a release agent other than the ester wax, but the content of the ester wax is preferably 20% by mass or more of the total content of the release agents, and the total content of the release agents is preferably within the range of 3 to 15% by mass of the toner particles.

[0128] The ester wax may be any of monoester wax, diester wax, triester wax, tetraester wax, and wax having five or more ester bonds.

[0129] Examples of ester waxes include monoesters obtained by reacting higher fatty acids with higher alcohols, diesters obtained by reacting higher fatty acids with dihydric alcohols or higher alcohols with dicarboxylic acids, triesters of trimethylolpropane and higher fatty acids, triesters of glycerin and higher fatty acids, tetraesters of pentaerythritol and higher fatty acids, esters obtained by reacting hydroxy acids such as citric acid with higher fatty acids or higher alcohols, and esters obtained by reacting aromatic carboxylic acids or alcohols such as cyclic acids with higher fatty acids or higher alcohols.

[0130] The hydrocarbon chains of the higher fatty acids and higher alcohols are preferably hydrocarbon chains having from 13 to 30 carbon atoms, and more preferably hydrocarbon chains having from 17 to 22 carbon atoms. The dihydric alcohols and dicarboxylic acids are preferably compounds having two hydroxy groups or two carboxy groups at both ends of a hydrocarbon group having from 1 to 30 carbon atoms.

[0131] Each of the hydrocarbon groups may be substituted with a linear or branched alkyl group, alkenyl group, alkynyl group, aromatic hydrocarbon ring group, aromatic heterocyclic group, non-aromatic hydrocarbon ring group, non-aromatic heterocyclic group, alkoxy group, cycloalkoxy group, aryloxy group, alkylthio group, cycloalkylthio group, arylthio group, alkoxycarbonyl group, aryloxycarbonyl group, sulfamoyl group, acyl group, acyloxy group, amido group, carbamoyl group, ureido group, sulfinyl group, alkylsulfonyl group, arylsulfonyl group or heteroarylsulfonyl group, amino group, halogen atom, fluorohydrocarbon group, cyano group, nitro group, hydroxy group, thiol group, silyl group, deuterium atom, or the like.

[0132] Specific examples of the ester wax include behenyl behenate, triglycerol behenate, pentaerythritol tetrastearate, stearyl stearate, pentaerythritol tetrabehenate, ethylene glycol stearate, ethylene glycol behenate, neopentyl glycol stearate, neopentyl glycol behenate, 1,6-hexanediol stearate, 1,6-hexanediol behenate, glycerin stearate, glycerin behenate, stearyl citrate, behenyl citrate, stearyl phosphate, behenyl phosphate, etc. The ester wax may be a natural wax such as carnauba wax.

[0133] From the viewpoint of suppressing tacking, the toner particles according to the present invention preferably further contain Fischer-Tropsch wax. Fischer-Tropsch wax is a hydrocarbon compound having 16 to 78 carbon atoms obtained from the distillation residue of hydrocarbons synthesized from a synthesis gas consisting of carbon monoxide and hydrogen, or obtained by hydrogenating such a hydrocarbon. The content of the Fischer-Tropsch wax is preferably within a range of 10 to 50 mass % of the total content of the release agent.

[0134] Other releasing agents may be contained, for example, low molecular weight polyethylene wax, low molecular weight polypropylene wax, microcrystalline wax, paraffin wax, etc.

[0135] <Coloring agent> The colorant contained in the toner base particles according to the present invention may be any known inorganic or organic colorant, including carbon black, magnetic powder, and various organic or inorganic pigments and dyes. The content of the colorant is in the range of 1 to 20% by mass, preferably 2 to 10% by mass, based on the toner particles.

[0136] <Charge control agent> The charge control agent that can be contained in the toner particles according to the present invention includes known compounds such as nigrosine dyes, metal salts of naphthenic acid or higher fatty acids, alkoxylated amines, quaternary ammonium salts, azo metal complexes, and metal salicylate salts. The charge control agent can provide a toner with excellent charging properties. The content of the charge control agent can usually be set within a range of 0.1 to 5.0 parts by mass with respect to 100 parts by mass of the binder resin.

[0137] <External additives> The toner particles can be used as they are, but may be treated with external additives such as a fluidizing agent and a cleaning aid in order to improve the flowability, chargeability, cleaning properties, and the like.

[0138] Examples of external additives include inorganic oxide fine particles such as silica fine particles, alumina fine particles, and titanium oxide fine particles, inorganic stearic acid compound fine particles such as aluminum stearate fine particles and zinc stearate fine particles, and inorganic titanic acid compound fine particles such as strontium titanate and zinc titanate, etc. These may be used alone or in combination of two or more. From the viewpoint of improving heat-resistant storage stability and environmental stability, it is preferable that these inorganic particles are subjected to a gloss treatment using a silane coupling agent, a titanium coupling agent, a higher fatty acid, a silicone oil, or the like.

[0139] The amount of external additive added (the total amount when multiple external additives are used) is preferably within a range of 0.05 to 5 parts by mass, more preferably within a range of 0.1 to 3 parts by mass, per 100 parts by mass of toner.

[0140] <Core-shell structure> The toner particles can be used as a toner as they are, but they may also be toner particles with a multilayer structure such as a core-shell structure, in which the toner particles are used as core particles and a shell layer covering the surface of the core particles. The shell layer does not have to cover the entire surface of the core particles, and the core particles may be partially exposed. The cross section of the core-shell structure can be confirmed by known observation means, such as a transmission electron microscope (TEM) or a scanning probe microscope (SPM).

[0141] In the case of a core-shell structure, the core particle and the shell layer can be made to have different properties such as glass transition point, melting point, and hardness, making it possible to design toner particles according to the purpose. For example, a shell layer can be formed by aggregating and fusing a resin with a relatively high glass transition point (Tg) to the surface of a core particle containing a binder resin, colorant, release agent, etc. and having a relatively low glass transition point (Tg). The shell layer preferably contains an amorphous resin.

[0142] <Toner particle size> The average particle size of the toner particles is the volume-based median diameter (d 50 ) is preferably in the range of 3 to 10 μm, more preferably in the range of 5 to 8 μm. Within the above range, high reproducibility can be obtained even for extremely minute dot images at the 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 organic solvent added, the fusion time, the composition of the binder resin, and the like.

[0143] The volume-based median diameter of the toner particles (d 50 For the measurement of ), a measuring device consisting of a Multisizer 3 (manufactured by Beckman Coulter) connected to a computer system equipped with data processing software Software V3.51 can be used. Specifically, the measurement sample (toner) is added to a surfactant solution (for example, a surfactant solution prepared by diluting a neutral detergent containing surfactant components 10 times with pure water in order to disperse toner particles), and then ultrasonic dispersion is performed to prepare a toner particle dispersion. This toner particle dispersion is then pipetted into a beaker containing an ISOTON II (manufactured by Beckman Coulter) in a sample stand until the concentration displayed on the measuring device reaches 8%. By achieving this concentration, reproducible measurement values ​​can be obtained. Then, with the measuring device, the measurement particle count is set to 25,000 particles and the aperture diameter is set to 100 μm. The measurement range of 2 to 60 μm is divided into 256 parts, and frequency values ​​are calculated. The particle sizes of the largest 50% of the particle sizes are taken as the volume-based median diameter (d 50 ) is obtained.

[0144] <Average circularity of toner particles> From the viewpoint of improving the stability of charging characteristics and low-temperature fixability, the toner particles preferably have an average circularity in the range of 0.930 to 1.000, and more preferably in the range of 0.950 to 0.995. If the average circularity is within the above range, the individual toner particles are less likely to be crushed, which can suppress contamination of the frictional charging member, stabilize the chargeability of the toner, and improve the quality of the formed image.

[0145] The average circularity of the toner particles can be measured using an FPIA-3000 (manufactured by Sysmex Corporation). Specifically, the measurement sample (toner) is soaked in an aqueous solution containing a surfactant and dispersed by ultrasonic dispersion for 1 minute. Then, using an FPIA-3000 (manufactured by Sysmex Corporation), images are taken using the measurement conditions HPF (high magnification imaging) mode at an appropriate density of 3,000 to 10,000 HPF detections. If the HPF detection count is within the above range, reproducible measurements can be obtained. From the captured particle images, the circularity of each toner particle is calculated according to the following formula (I), and the average circularity is obtained by adding up the circularity of each toner particle and dividing by the total number of toner particles. Formula (I) Circularity = (perimeter of a circle with the same projected area as the particle image) / (perimeter of the projected particle image)

[0146] <Method for manufacturing toner for developing electrostatic images> The method for producing the toner for developing electrostatic images of the present invention is not particularly limited, and examples thereof include known methods such as a kneading and pulverization method, a suspension polymerization method, an emulsion aggregation method, a solution suspension method, a polyester elongation method, and a dispersion polymerization method. Among these, it is preferable to employ the emulsion aggregation method from the viewpoint of uniformity of particle size and controllability of shape.

[0147] <Emulsification aggregation method> The emulsion aggregation method is a method for producing toner particles by mixing a dispersion of binder resin particles (hereinafter also referred to as "binder resin particles") dispersed with a surfactant or a dispersion stabilizer with a dispersion of colorant particles (hereinafter also referred to as "colorant particles") as needed, aggregating them to a desired toner particle size, and further controlling the shape by fusing the binder resin particles together. Here, the binder resin particles contain ester wax, other release agents, charge control agents, etc. as needed. As a preferred method for producing the toner according to the present invention, an example of obtaining toner particles having a core-shell structure by emulsion aggregation will be described below.

[0148] (1) A step of preparing a colorant particle dispersion in which colorant particles are dispersed in an aqueous medium. (2) A step of preparing a resin particle dispersion (core / shell resin particle dispersion) in which binder resin particles containing internal additives (such as a release agent) as needed are dispersed in an aqueous medium. (3) A step of mixing a colorant particle dispersion and a core resin particle dispersion to obtain a resin particle dispersion for aggregation, and aggregating and fusing the colorant particles and binder resin particles in the presence of an aggregating agent to form aggregated particles as core particles (aggregation and fusion step). (4) A process of adding a dispersion of shell resin particles containing binder resin particles for the shell layer to a dispersion containing core particles, and aggregating and fusing the particles for the shell layer onto the surface of the core particles to form toner base particles with a core-shell structure (aggregation and fusion process). (5) A process of filtering the toner base particles from the toner base particle dispersion (toner base particle dispersion) and removing surfactants, etc. (washing process) (6) Step of drying the toner base particles (drying step) (7) A step of adding an external additive to the toner base particles (an external additive treatment step)

[0149] Toner particles having a core-shell structure can be obtained by first preparing core particles by aggregating and fusing binder resin particles for the core particles and colorant particles, then adding binder resin particles for the shell layer to a dispersion of the core particles and aggregating and fusing the binder resin particles for the shell layer to the surface of the core particles to form a shell layer that covers the surface of the core particles. However, toner particles formed from a single layer of particles can also be produced in the same way, for example, without adding a dispersion of shell resin particles in the above step (4).

[0150] <External additive treatment> The external additives can be mixed with the toner base particles using a mechanical mixer. Examples of mechanical mixers that can be used include a Henschel mixer, a Nauta mixer, and a Turbula mixer. Among these, a mixer capable of applying shear force to the particles to be mixed, such as a Henschel mixer, may be used, and the mixing process may be performed by lengthening the mixing time or increasing the rotational peripheral speed of the stirring blades. When multiple types of external additives are used, all of the external additives may be mixed with the toner base particles at once, or may be mixed in multiple batches depending on the external additive.

[0151] The degree of disintegration and adhesion strength of the external additive can be adjusted by controlling the mixing intensity, that is, the peripheral speed of the stirring blade, the mixing time, the mixing temperature, etc., using the mechanical mixer.

[0152] <Electrostatic image developer> The toner for developing electrostatic images of the present invention can be used as a magnetic or non-magnetic one-component electrostatic image developer. It can also be used as a two-component electrostatic image developer by mixing it with a carrier. When the toner is used as a two-component electrostatic image developer, magnetic particles made of a conventionally known material such as a metal such as iron, ferrite, or magnetite, or an alloy of such a metal with a metal such as aluminum or lead can be used as the carrier, and ferrite particles are particularly preferred.

[0153] The carrier may be a coated carrier in which the surface of magnetic particles is coated with a coating agent such as resin, or a dispersion type carrier in which magnetic powder is dispersed in a binder resin. The volume-based median diameter of the carrier (d 50 ) 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 of the carrier (d 50 ) can be measured, for example, by a laser diffraction particle size distribution measuring device HELOS (manufactured by SYMPATEC) equipped with a wet disperser. [Example]

[0154] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these. In the examples, the terms "parts" and "%" are used, but unless otherwise specified, they represent "parts by mass" or "% by mass."

[0155] <Preparation of Colorant Particle Dispersion (Cyan)> 90 parts by weight of sodium dodecyl sulfate was added to 1,600 parts by weight of ion-exchanged water, and while stirring the solution, 420 parts by weight of the colorant "CI Pigment Blue 15:3" was gradually added. A colorant particle dispersion was prepared by dispersing the solution using a stirring device CLEARMIX (manufactured by M Technique Co., Ltd., "CLEARMIX" is a registered trademark of the company).

[0156] The colorant particles in the dispersion had a volume-based median diameter of 110 nm. The volume-based median diameter of the colorant particles was measured using a Microtrac particle size distribution analyzer "UPA-150" (manufactured by Nikkiso Co., Ltd.). Hereinafter, in this example, the particle size of each particle was measured in the same manner.

[0157] <Synthesis of crystalline polyester resin 1 (CP1)> The following raw material monomers for the styrene-acrylic polymerized segment, an amphoteric compound, and a radical polymerization initiator were placed in a dropping funnel. Styrene 36 parts by mass n-Butyl acrylate 13 parts by mass Acrylic acid (amphoteric compound) 2 parts by mass Di-t-butyl peroxide radical (polymerization initiator) 7 parts by mass

[0158] Furthermore, the raw material monomers for the crystalline polyester polymer segment described below were placed in a four-neck flask equipped with a nitrogen gas inlet tube, a dehydration tube, a stirrer and a thermocouple, and heated to 170° C. to dissolve them. Sebacic acid 344 parts by mass 1,10-Decanediol 296 parts by mass

[0159] Next, the raw materials placed in the dropping funnel were added dropwise to the four-neck flask over a period of 90 minutes while stirring. After that, the mixture was aged for 60 minutes, and unreacted monomer was removed under reduced pressure (8 kPa). The amount of monomer removed was very small compared to the amount of monomer charged.

[0160] Next, 0.8 parts by mass of titanium tetrabutoxide (Ti(On-Bu)4) was added as an esterification catalyst, the temperature was raised to 235°C, and the reaction was carried out under normal pressure (101.3 kPa) for 5 hours and then under reduced pressure (8 kPa) for 1 hour.

[0161] The mixture was then cooled to 200° C. and reacted for an additional hour under reduced pressure (20 kPa), after which the solvent was removed to obtain a crystalline polyester resin 1 (CP1) which was a hybrid crystalline polyester resin.

[0162] Crystalline polyester resin 1 (CP1) had a weight average molecular weight of 21,600, a melting point of 77° C., and an acid value of 18 mgKOH / g.

[0163] <Synthesis of Crystalline Polyester Resins 2 to 13 (CP2 to CP13)> Crystalline polyester resins 2 to 13 (CP2 to CP13) were obtained in the same manner as in the synthesis of crystalline polyester resin 1 (CP1), except that the types and amounts of dicarboxylic acid monomers and dialcohol monomers were changed as shown in Table I.

[0164] The weight average molecular weight, melting point and acid value of crystalline polyester resins 2 to 13 (CP2 to CP13) are as shown in Table 1.

[0165] <Preparation of Crystalline Polyester Resin Particle Dispersion> 100 parts by weight of each synthesized crystalline polyester resin was dissolved in 400 parts by weight of ethyl acetate and mixed with 638 parts by weight of a 0.26% by weight sodium dodecyl sulfate solution. While stirring, the resulting mixture was subjected to ultrasonic dispersion treatment at V-LEVEL 300 μA for 30 minutes using an ultrasonic homogenizer US-150T (manufactured by Nippon Seiki Seisakusho Co., Ltd.).

[0166] Next, while heating to 40°C, the ethyl acetate was completely removed by stirring under reduced pressure for 3 hours using a diaphragm vacuum pump V-700 (manufactured by BUCHI), to obtain each crystalline polyester resin particle dispersion liquid with a solid content of 13.5 mass%.

[0167] The crystalline polyester resin particles in the dispersion had a volume-based median diameter of 160 nm.

[0168] <Synthesis of amorphous polyester resin 1 (AP1)> A mixture of the following raw material monomers for the styrene-acrylic polymerized segment, an amphoteric compound, and a radical polymerization initiator was placed in a dropping funnel. Styrene 80 parts by mass n-Butyl acrylate 20 parts by mass Acrylic acid (amphoteric compound) 10 parts by mass Di-t-butyl peroxide radical (polymerization initiator) 16 parts by mass

[0169] Furthermore, the raw material monomers for the amorphous polyester polymer segment described below were placed in a four-neck flask equipped with a nitrogen gas inlet tube, a dehydration tube, a stirrer and a thermocouple, and heated to 170° C. to dissolve them. Bisphenol A propylene oxide 2 mole adduct 284.3 parts by mass 1,10-decanediol 0.7 parts by mass Terephthalic acid 66.2 parts by mass Fumaric acid 47.4 parts by mass Sebacic acid 0.8 parts by mass

[0170] Next, the raw materials placed in the dropping funnel were added dropwise to the four-neck flask over a period of 90 minutes while stirring. After that, the mixture was aged for 60 minutes, and unreacted monomer was removed under reduced pressure (8 kPa). The amount of monomer removed was very small compared to the amount of monomer charged.

[0171] Next, 0.4 parts by mass of titanium tetrabutoxide (Ti(On-Bu)4) was added as an esterification catalyst, the temperature was raised to 235°C, and the reaction was carried out under normal pressure (101.3 kPa) for 5 hours and then under reduced pressure (8 kPa) for 1 hour.

[0172] Next, the mixture was cooled to 200° C., and the reaction was continued for another hour under reduced pressure (20 kPa), after which the solvent was removed to obtain Amorphous Polyester Resin 1 (AP1), which was a hybrid amorphous polyester resin.

[0173] Amorphous polyester resin 1 (AP1) had a weight average molecular weight of 25,000 and a glass transition point of 60°C.

[0174] <Synthesis of amorphous polyester resins 2 to 9 (AP2 to 9)> Amorphous polyester resins 2 to 9 (AP2 to AP9) were obtained in the same manner as in the synthesis of amorphous polyester resin 1 (AP1), except that the types and amounts of dicarboxylic acid monomers and dialcohol monomers were changed as shown in Table II.

[0175] The weight average molecular weights and glass transition points of amorphous polyester resins 2 to 9 (AP2 to AP9) are as shown in Table 2.

[0176] <Preparation of Amorphous Polyester Resin Particle Dispersion> 100 parts by mass of each of the synthesized amorphous polyester resins was dissolved in 400 parts by mass of ethyl acetate and mixed with 638 parts by mass of a 0.26% by mass sodium dodecyl sulfate solution. While stirring the resulting mixture, ultrasonic dispersion treatment was performed for 30 minutes at V-LEVEL 300 μA using an ultrasonic homogenizer US-150T (manufactured by Nippon Seiki Seisakusho Co., Ltd.).

[0177] Next, while heating to 40°C, the ethyl acetate was completely removed by stirring under reduced pressure for 3 hours using a diaphragm vacuum pump V-700 (manufactured by BUCHI), to obtain each amorphous polyester resin particle dispersion liquid with a solid content of 13.5 mass%.

[0178] The amorphous polyester resin particles in the dispersion had a volume-based median diameter of 160 nm.

[0179] <Preparation of amorphous vinyl resin (SP1) particle dispersion> (First stage polymerization) A 5 L reaction vessel equipped with a stirrer, a temperature sensor, a condenser, and a nitrogen introducing device was charged with 8 parts by mass of sodium dodecyl sulfate and 3,000 parts by mass of ion-exchanged water, and the internal temperature was raised to 80° C. while stirring at a stirring speed of 230 rpm under a nitrogen stream. After the temperature was raised, a solution prepared by dissolving 10 parts by mass of potassium persulfate in 200 parts by mass of ion-exchanged water was added, the liquid temperature was again raised to 80° C., and a mixed liquid of the following monomers was added dropwise over 1 hour. Styrene 570 parts by mass n-Butyl acrylate 165 parts by mass Methacrylic acid 68 parts by mass

[0180] After the dropwise addition of the mixed liquid, polymerization was carried out by heating and stirring at 80° C. for 2 hours to prepare an amorphous vinyl resin particle dispersion liquid (1-a).

[0181] (Second stage polymerization) A solution of 3 parts by mass of sodium polyoxyethylene (2) dodecyl ether sulfate dissolved in 1,210 parts by mass of ion-exchanged water was placed in a reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introducing device, and heated to 80° C. After heating, 60 parts by mass, calculated as solid content, of the amorphous vinyl resin particle dispersion (1-a) prepared by the first-stage polymerization described above and a mixed solution prepared by dissolving the following monomers, chain transfer agent, and release agent at 80° C. were added. Styrene 245 parts by mass 2-Ethylhexyl acrylate 97 parts by mass Methacrylic acid 30 parts by mass n-Octyl-3-mercaptopropionate 4 parts by mass Behenic acid behenate 170 parts by mass

[0182] The melting point of the behenic acid behenate used as the release agent is 73°C.

[0183] A dispersion containing emulsified particles (oil droplets) was prepared by mixing and dispersing for one hour using a CLEARMIX agitator (manufactured by M-Technique Co., Ltd., "CLEARMIX" is a registered trademark of the company) with a circulation path. A polymerization initiator solution of 5.2 parts by mass of potassium persulfate dissolved in 200 parts by mass of ion-exchanged water and 1,000 parts by mass of ion-exchanged water were added to this dispersion, and the system was heated and stirred at 84°C for one hour to polymerize, preparing amorphous vinyl resin particle dispersion (1-b).

[0184] (Third stage polymerization) A solution of 7 parts by mass of potassium persulfate dissolved in 130 parts by mass of ion-exchanged water was added to the amorphous vinyl resin particle dispersion (1-b) obtained by the second-stage polymerization. Further, a mixed solution of the following monomers and chain transfer agent was added dropwise over 1 hour at a temperature of 82°C. Styrene 350 parts by mass Methyl methacrylate 50 parts by mass n-Butyl acrylate 170 parts by mass Methacrylic acid 35 parts by mass n-Octyl-3-mercaptopropionate 8 parts by mass

[0185] After the dropwise addition was completed, polymerization was carried out by heating and stirring for 2 hours, and then the mixture was cooled to 28° C. to obtain a particle dispersion of amorphous vinyl resin 1 (SP1).

[0186] The volume-based median diameter of the amorphous vinyl resin 1 (SP1) particles in the dispersion was 145 nm. The weight-average molecular weight of the resulting amorphous vinyl resin 1 (SP1) was 35,000, and the glass transition temperature was 37°C.

[0187] Amorphous vinyl resin 2 (SP2) particle dispersion was obtained in the same manner as in the preparation of amorphous vinyl resin 1 (SP1) particle dispersion, except that the type and amount of release agent used in the second-stage polymerization was changed as follows: Behenic acid behenate 136 parts by mass Fischer-Tropsch wax 34 parts by mass

[0188] The melting point of the behenic acid behenate used as the release agent is 73°C, and the melting point of the Fischer-Tropsch wax is 90°C.

[0189] <Manufacturing the No. 1 toner> A reaction vessel equipped with a stirrer, temperature sensor, and cooling tube was charged with 527 parts by weight (solids content) of the amorphous vinyl resin particle dispersion (SP1) prepared above, 33 parts by weight (solids content) of the colorant particle dispersion, and 500 parts by weight of ion-exchanged water. A 5 mol / L aqueous solution of sodium hydroxide was added to adjust the pH to 10. Further, a solution of 60.8 parts by weight of magnesium chloride hexahydrate diluted two-fold with ion-exchanged water was added over 10 minutes at 30°C while stirring. After allowing to stand for 3 minutes, the mixture was heated to 80°C over 60 minutes. After reaching 80°C, a solution of 10 parts by weight of magnesium chloride hexahydrate diluted two-fold with ion-exchanged water was added over 10 minutes at 30°C while stirring, and the mixture was allowed to stand for 5 minutes.

[0190] Next, a dispersion of the following components was added to the above mixed dispersion over 30 minutes. The parts by mass shown below are calculated as solid content. Crystalline polyester resin 1 (CP1) particle dispersion 35 parts by mass Crystalline polyester resin 2 (CP2) particle dispersion 35 parts by mass Dodecyldiphenyletherdisulfonic acid sodium salt 10 parts by mass

[0191] When the supernatant of the reaction solution became transparent, the stirring speed was adjusted so that the particle size growth rate was 0.02 μm / min. When the volume-based median diameter measured using a Coulter Multisizer 3 (Beckman Coulter) reached 5.8 μm, the stirring speed was adjusted to stop the particle size growth.

[0192] Next, 70 parts by mass (solid content equivalent) of the amorphous polyester resin (AP1) particle dispersion was added over 30 minutes, and when the supernatant of the reaction solution became transparent, an aqueous solution in which 80 parts by mass of sodium chloride was dissolved in 320 parts by mass of ion-exchanged water was added to stop the growth of particle size.

[0193] Next, the temperature was raised to 80°C and the mixture was stirred. Using a flow particle image analyzer "FPIA-3000" (manufactured by Sysmex Corporation), when the average circularity of the toner base particles reached 0.970, the reaction liquid was cooled to 25°C at a cooling rate of 10°C / min, thereby obtaining a dispersion of toner base particles.

[0194] Next, solid-liquid separation was performed, and the dehydrated cake of toner base particles was redispersed in ion-exchanged water and washed by repeating the solid-liquid separation operation three times. After washing, the toner base particles were obtained by drying at 35°C for 24 hours.

[0195] To 100 parts by mass of the obtained toner base particles, 0.6 parts by mass of hydrophobic silica particles (number average primary particle size: 12 nm, hydrophobicity: 68), 1.0 part by mass of hydrophobic titanium oxide particles (number average primary particle size: 20 nm, hydrophobicity: 63), and 1.0 part by mass of sol-gel silica (number average primary particle size: 110 nm, hydrophobicity: 63) were added, and mixed in a Henschel mixer (manufactured by Nippon Coke and Engineering Co., Ltd.) at a rotor peripheral speed of 40 m / s and 32°C for 20 minutes. After mixing, coarse particles were removed using a sieve with 45 μm openings, and toner No. 1 was obtained.

[0196] The obtained toner No. 1 had a volume-based median diameter of the toner particles of 5.9 μm.

[0197] <Production of Toner Nos. 2 to 29> Toners Nos. 2 to 29 were obtained in the same manner as in the production of Toner No. 1, except that the types and amounts of the amorphous vinyl resin particle dispersion, amorphous polyester resin particle dispersion, and crystalline polyester resin particle dispersion were changed to those shown in Table III.

[0198] <Production of Developers No. 1 to 29> The toner thus produced was mixed with an acrylic resin-coated ferrite carrier having a volume average particle size of 32 μm so that the toner concentration was 6 mass %. In this way, two-component developers Nos. 1 to 29 containing toner Nos. 1 to 29, respectively, were produced.

[0199] <Evaluation of low-temperature fixability> The fixing device of the multifunction printer "bizhub PRESS (registered trademark) C1070" (manufactured by Konica Minolta, Inc.) was modified to be able to change the surface temperatures of the upper fixing belt and the lower fixing roller, and two-component developers were loaded sequentially. The device was also modified to be able to freely set the fixing temperature, toner adhesion amount, and system speed. Under normal temperature and humidity conditions (temperature 20°C, humidity 50% RH), A4 size high-quality paper "NPI high-quality (127.9 g / m 2 ) (Nippon Paper Industries Co., Ltd.) with a deposition rate of 11.3 g / m 2 The fixing temperature was set to 110°C. A fixing experiment was then conducted to fix a 100mm x 100mm image, with the set fixing temperature being increased in 2°C increments from 110°C up to 180°C. The lowest fixing temperature at which image staining due to fixing offset was not visually confirmed was defined as the minimum fixing temperature (UO avoidance temperature). The low-temperature fixability was then evaluated according to the following evaluation criteria. The evaluation results are shown in Table IV.

[0200] (Evaluation criteria) ◎: Minimum fixing temperature is less than 135°C (excellent toner with excellent low-temperature fixing properties) ○: Minimum fixing temperature is 135°C or higher and lower than 140°C (a level that is practically acceptable) ×: Minimum fixing temperature is 140°C or higher (not sufficiently fixed at the target paper feed speed, a level that is problematic for practical use)

[0201] <Tacking evaluation> The fixing device of the multifunction printer "bizhub PRESS (registered trademark) C1070" (manufactured by Konica Minolta, Inc.) was modified so that the surface temperatures of the upper fixing belt and the lower fixing roller could be changed, and two-component developers were loaded sequentially. The above device was also modified so that the fixing temperature, toner adhesion amount, system speed, and paper discharge air could be freely set. In an environment of normal temperature and humidity (temperature 20°C, humidity 50% RH), A4 size coated paper "OK ​​Topcoat+ (157.0 g / m 2 ) (Oji Paper Co., Ltd.) with a deposition rate of 10.2 g / m 2A fixing experiment was carried out on 800 sheets at a fixing temperature of 180°C to output a solid image.

[0202] To record the paper surface temperature, a thermocouple molded surface sensor: MF-OK (Toa Kiki) was attached to the center of the paper for the 1st, 100th, 200th, 300th, 400th, 500th, 600th, and 700th images ejected. After all 800 sheets of fixed images were loaded onto the ejection tray, the paper was left for 8 hours to cool down. The highest temperature reached from the time the paper was ejected until it cooled down was recorded as the measured temperature for that paper.

[0203] After leaving it for 8 hours, the degree to which the overlapping images were stuck together was evaluated for the 1st, 100th, 200th, 300th, 400th, 500th, 600th, and 700th images.

[0204] The measured temperature at the image that was judged to be OK according to the following evaluation criteria was taken as the tacking removal temperature. The measured temperature could be controlled by changing the volume of the discharge air, and if the 1st, 100th, 200th, 300th, 400th, 500th, 600th, and 700th images all failed, the volume of the discharge air was increased and the same experiment was repeated until an OK-level image was obtained.

[0205] (Evaluation criteria) OK: The toner image can be easily peeled off by hand and the toner image surface is not rough. NG: The toner image surface is rough after peeling.

[0206] The tacking-removal temperatures are shown in Table 4. The higher the tacking-removal temperature, the less likely the toner is to cause tacking, with 56°C or higher being the acceptable level.

[0207] [Table 1]

[0208] [Table 2]

[0209] [Table 1]

[0210] [Table 2]

[0211] As shown by the above results, it is clear that the toner of the present invention is superior to the toner of the comparative example in terms of low-temperature fixability and suppression of tacking. In Tables III and IV, "the present invention" in the remarks column for each Toner No. 10 should be read as "Reference Example."

Claims

1. A toner for developing electrostatic images, comprising at least toner particles, the toner particles contain an amorphous vinyl resin, an amorphous polyester resin, a crystalline polyester resin, and an ester wax; the crystalline polyester resin contains at least one crystalline polyester resin A obtained by polycondensation of a dicarboxylic acid having at least 9 to 14 carbon atoms and a dialcohol having at least 9 to 14 carbon atoms; the amorphous polyester resin is an amorphous polyester resin containing a structural unit derived from a dicarboxylic acid having 9 to 14 carbon atoms or a dialcohol having 9 to 14 carbon atoms, The structural units contained in the amorphous polyester resin include a structural unit derived from the same dicarboxylic acid or dialcohol as a raw material monomer of the crystalline polyester resin A, and the total number of carbon atoms of the dicarboxylic acid and the dialcohol to be polycondensed to obtain the crystalline polyester resin A is within the range of 18 to 24, the amorphous polyester resin contains structural units derived from a dicarboxylic acid having 9 to 14 carbon atoms or a dialcohol having 9 to 14 carbon atoms in an amount of 1 to 20 mol % relative to the total amount of the amorphous polyester resin.

2. 2. The toner for developing electrostatic images according to claim 1, wherein 50% by mass or more of the total amount of the crystalline polyester resin is crystalline polyester resin A obtained by polycondensation of the dicarboxylic acid having 9 to 14 carbon atoms and the dialcohol having 9 to 14 carbon atoms.

3. 3. The toner for developing electrostatic images according to claim 1, wherein all of the crystalline polyester resins are crystalline polyester resins A obtained by polycondensation of the dicarboxylic acid having 9 to 14 carbon atoms and the dialcohol having 9 to 14 carbon atoms.

4. 4. The toner for developing electrostatic images according to claim 1, wherein the crystalline polyester resin has an acid value in the range of 20 to 30 mgKOH / g.

5. 5. The toner for developing electrostatic images according to claim 1, wherein the crystalline polyester resin is a hybrid crystalline polyester resin in which a crystalline polyester polymer segment and a vinyl polymer segment having a styrene-derived structural unit are chemically bonded to each other.

6. 6. The toner for developing electrostatic images according to claim 1, wherein the amorphous polyester resin is a hybrid amorphous polyester resin in which an amorphous polyester polymer segment and a vinyl polymer segment having a styrene-derived structural unit are chemically bonded to each other.

7. 7. The toner for developing electrostatic images according to claim 1, further comprising a Fischer-Tropsch wax.

8. The content W of the amorphous polyester resin ａｐ and the content W of the crystalline polyester resin ｃｐ Ratio of W ａｐ / W ｃｐ 8. The toner for developing electrostatic images according to claim 1, wherein the value of (I) is in the range of 0.5 to 1.

5.

9. An electrostatic image developer comprising the toner for developing electrostatic images according to any one of claims 1 to 8.

Images