Toner for developing electrostatic images

Abstract

To provide toner for electrostatic charge image development including pigments having favorable color developability and having image scratch resistance, and manufacturing method of the toner.SOLUTION: Toner for electrostatic charge image development includes a binder resin, ester compositions (E) and a colorant. The ester compositions (E) are one or more types selected from: an ester composition (E1) containing a condensate of a carboxylic acid component (E1-ac) containing an aliphatic monocarboxylic acid compound with 10 or more and 30 or less carbon atoms, and an alcohol component (E1-al) containing a dihydric or higher aliphatic alcohol with 2 or more and 14 or less carbon atoms; and an ester composition (E2) containing a condensate of an alcohol component (E2-al) containing an aliphatic monoalcohol with 10 or more and 30 or less carbon atoms, and a carboxylic acid component (E2-ac) containing divalent or higher aliphatic carboxylic acid compound with 2 or more and 14 or less carbon atoms, where a sum of the acid value and hydroxyl value of the ester compositions (E) is 70 mgKOH / g or more and 400 mgKOH or less. A manufacturing method of the toner for electrostatic charge image development is also provided.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an electrostatic image developing toner used for developing latent images formed in methods such as electrophotography, electrostatic recording, and electrostatic printing, and to a method for manufacturing the same. [Background technology]

[0002] In recent years, the market has shifted from office printing to commercial printing, resulting in an increased demand for higher resolution and reliability in printed materials.

[0003] For example, Patent Document 1 describes an ester composition containing a condensate of a colorant, a resin composition obtained by condensing an amorphous polyester resin (A) having an acid group with an amine compound, and an ester composition containing a condensate of a carboxylic acid component (CI-ac) containing 20 mol% or more of an aliphatic monocarboxylic acid compound having 10 to 30 carbon atoms and an alcohol component (CI-al) containing 90 mol% or more of a divalent or higher aliphatic alcohol having 2 to 14 carbon atoms, or an ester composition containing a condensate of an alcohol component (CI-al) containing 20 mol% or more of aliphatic monoalcohol having 10 to 30 carbon atoms and a carboxylic acid component (CI-ac) containing 90 mol% or more of a divalent or higher aliphatic carboxylic acid compound having 2 to 14 carbon atoms, or both thereof. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2021-47403 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] However, it was found that while the image density of printed materials improved with the toner using the ester composition described in Patent Document 1, the low SP value and low molecular weight of the ester composition caused it to localize on the surface of the printed image, significantly reducing the image intensity. Furthermore, it was found that the low SP value of the ester composition resulted in insufficient dispersion of pigments containing many hydrophilic groups, such as yellow pigment and magenta pigment, and consequently, insufficient image density could not be obtained.

[0006] The present invention relates to a toner for electrostatic image development that exhibits good pigment color development and good image scratch resistance, and a method for manufacturing the same. [Means for solving the problem]

[0007] The present invention [1] A toner for developing electrostatic images containing a binder resin, an ester composition (E), and a colorant, wherein the ester composition (E) is An ester composition (E1) containing a condensate of a carboxylic acid component (E1-ac) containing 55 mol% or more of an aliphatic monocarboxylic acid compound having 10 to 30 carbon atoms, and an alcohol component (E1-al) containing 80 mol% or more of a divalent or higher aliphatic alcohol having 2 to 14 carbon atoms, and An ester composition (E2) containing a condensate of an alcohol component (E2-al) containing 55 mol% or more of an aliphatic monoalcohol having 10 to 30 carbon atoms, and a carboxylic acid component (E2-ac) containing 80 mol% or more of a divalent or higher aliphatic carboxylic acid compound having 2 to 14 carbon atoms. One or more selected from, A toner for developing electrostatic images, wherein the sum of the acid value and hydroxyl value of the ester composition (E) is 70 mg KOH / g or more and 400 mg KOH or less, and [2] A method for producing electrostatic image developing toner according to [1], comprising the steps of: melting and kneading a mixture containing a binder resin, an ester composition (E), and a colorant to obtain a molten kneaded product; and crushing and classifying the molten kneaded product to obtain toner particles. Regarding. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a toner for electrostatic image development that has good pigment color development and good image scratch resistance. [Modes for carrying out the invention]

[0009] The electrostatic image developing toner of the present invention (hereinafter also simply referred to as "the toner of the present invention") is an electrostatic image developing toner containing a binder resin, an ester composition (E), and a colorant, wherein the ester composition (E) is one or more selected from ester compositions (E1) containing a condensate of a carboxylic acid component mainly composed of an aliphatic monocarboxylic acid compound with a predetermined number of carbon atoms and an alcohol component mainly composed of an aliphatic alcohol with a predetermined number of carbon atoms and a carboxylic acid component mainly composed of an aliphatic monoalcohol with a predetermined number of carbon atoms and a carboxylic acid component mainly composed of an aliphatic carboxylic acid compound with a predetermined number of carbon atoms and a carboxylic acid component with a predetermined number of carbon atoms and a carboxylic acid compound with a predetermined number of carbon atoms and a carboxylic acid component, and is characterized in that the sum of the acid value and the hydroxyl value is within a predetermined range. According to the toner of the present invention, printed materials can be obtained that have good color development of yellow pigments and magenta pigments, as well as good image abrasion resistance.

[0010] The detailed reasons why the effects of this invention are obtained are not entirely clear, but they can be thought to be as follows. The toner of the present invention contains an ester composition (E) containing a long-chain monoalcohol or monocarboxylic acid in its molecular chain. This ester composition (E) has a high affinity for the hydrophobic surface of the colorant and contributes to the dispersion of the colorant as a wetting agent. Furthermore, by having a predetermined amount of carboxylic acid terminus, hydroxyl group terminus, or both, the ester composition (E) also has good affinity for the hydrophilic surface of the pigment and exhibits very high pigment dispersibility compared to conventional ester compositions. It is also presumed that having a predetermined amount of carboxylic acid terminus, hydroxyl group terminus, or both contributes to dispersion stabilization in the binder resin, suppressing localization on the image surface during heating and thus suppressing deterioration of image abrasion resistance.

[0011] In the present invention, the binder resin is not particularly limited as long as it is a resin used as the binder resin of the toner, and examples thereof include polyester resins, vinyl resins such as styrene-acrylic resins, epoxy resins, polycarbonates, polyurethanes, and composite resins containing two or more of these resins. However, in the present invention, from the viewpoint of fixing property, it is preferable to include polyester-based resins such as polyester resins and composite resins having a polyester resin and a styrene-based resin. The polyester-based resin is preferably amorphous, and as the amorphous polyester-based resin, an amorphous polyester resin is preferable.

[0012] Note that the crystallinity of the resin is represented by a crystallinity index defined by the ratio of the softening point to the maximum peak temperature of heat absorption measured by a differential scanning calorimeter, that is, the value of [softening point / maximum peak temperature of heat absorption]. The crystalline resin is a resin having a crystallinity index of 0.6 or more, preferably 0.7 or more, more preferably 0.9 or more, and 1.4 or less, preferably 1.2 or less, more preferably 1.1 or less. On the other hand, the amorphous resin is a resin in which no endothermic peak is observed, or if an endothermic peak is observed, the crystallinity index exceeds 1.4, preferably exceeds 1.5, more preferably is 1.6 or more, or is less than 0.6, preferably 0.5 or less. The crystallinity of the resin can be adjusted by the type and ratio of the raw material monomers, and manufacturing conditions (for example, reaction temperature, reaction time, cooling rate), etc. Note that the maximum peak temperature of heat absorption refers to the temperature of the peak having the largest peak area among the observed endothermic peaks. In the crystalline resin, the maximum peak temperature of heat absorption is taken as the melting point.

[0013] The amorphous polyester resin is preferably a polycondensate of an alcohol component containing an alkylene oxide adduct of bisphenol A and a carboxylic acid component.

[0014] The alkylene oxide adduct of bisphenol A has the formula (I):

[0015]

Chemical formula

[0016] (In the formula, OR and RO are oxyalkylene groups, R is an ethylene group and / or a propylene group, x and y represent the average number of moles of alkylene oxide added, each being a positive number, and the sum of x and y is 1 or greater, preferably 1.5 or greater, and 16 or less, preferably 8 or less, more preferably 6 or less, and even more preferably 4 or less.) Compounds represented by are preferred, including ethylene oxide adducts of bisphenol A and propylene oxide adducts of bisphenol A.

[0017] The content of the bisphenol A alkylene oxide adduct represented by formula (I) is preferably 70 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, and 100 mol% or less, and particularly preferably 100 mol%, in the alcohol component.

[0018] Other alcohol components include aliphatic diols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-butenediol, 1,3-butanediol, and neopentyl glycol, as well as trivalent or higher alcohols such as bisphenol A, hydrogenated bisphenol A, and glycerin.

[0019] Examples of carboxylic acid components include aromatic dicarboxylic acids, aliphatic dicarboxylic acids, trivalent or higher carboxylic acids, anhydrides of these acids, and alkyl esters of these acids with 1 to 3 carbon atoms.

[0020] Examples of aromatic dicarboxylic acid compounds include phthalic acid, isophthalic acid, terephthalic acid, anhydrides of these acids, and alkyl esters of these acids with 1 to 3 carbon atoms. Among these, terephthalic acid is preferred.

[0021] Examples of aliphatic dicarboxylic acid compounds include oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid and adipic acid which may be substituted with hydrocarbon groups having 1 to 20 carbon atoms, anhydrides of these acids, and alkyl esters of these acids with alkyl groups having 1 to 3 carbon atoms.

[0022] Examples of carboxylic acid compounds with a valency of 3 or higher include carboxylic acid compounds with a valency of 3 or higher such as 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalentricarboxylic acid, and pyromellitic acid, as well as anhydrides of these acids and alkyl esters of these acids with an alkyl group having 1 to 3 carbon atoms.

[0023] In this specification, macromonomers and hydroxycarboxylic acids are not included in the alcohol and carboxylic acid components.

[0024] Furthermore, the alcohol component may appropriately contain a monohydric alcohol, and the carboxylic acid component may appropriately contain a monohydric carboxylic acid compound.

[0025] The equivalent ratio (COOH group / OH group) of the carboxyl group of the carboxylic acid component to the hydroxyl group of the alcohol component is preferably 0.6 or higher, more preferably 0.7 or higher, even more preferably 0.75 or higher, and preferably 1.2 or lower, more preferably 1.15 or lower.

[0026] Amorphous polyester resins can be produced, for example, by polycondensing an alcohol component and a carboxylic acid component, which are raw material monomers, in an inert gas atmosphere, preferably in the presence of an esterification catalyst, and optionally in the presence of an esterification co-catalyst, polymerization inhibitor, etc., at a temperature preferably 160°C or higher, more preferably 200°C or higher, and preferably 250°C or lower, more preferably 240°C or lower.

[0027] Examples of esterification catalysts include tin compounds such as dibutyltin oxide and tin(II) 2-ethylhexanoate, and titanium compounds such as titanium diisopropylate bistriethanolamine, with tin compounds being preferred. The amount of esterification catalyst used is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, and preferably 1.5 parts by mass or less, and more preferably 1 part by mass or less, per 100 parts by mass of raw material monomer. Examples of esterification co-catalysts include gallic acid. The amount of esterification co-catalyst used is preferably 0.001 parts by mass or more, more preferably 0.01 parts by mass or more, and preferably 0.5 parts by mass or less, and more preferably 0.1 parts by mass or less, per 100 parts by mass of raw material monomer. Examples of polymerization inhibitors include tert-butylcatechol. The amount of polymerization inhibitor used is preferably 0.001 parts by mass or more, more preferably 0.01 parts by mass or more, and preferably 0.5 parts by mass or less, and more preferably 0.1 parts by mass or less, per 100 parts by mass of raw material monomer.

[0028] In this invention, the amorphous polyester resin may be an amorphous polyester resin that has been modified to such an extent that its properties are not substantially impaired. Examples of modified amorphous polyester resins include amorphous polyester resins that have been grafted or blocked with phenol, urethane, epoxy, etc., by methods described in Japanese Patent Publication No. 11-133668, Japanese Patent Publication No. 10-239903, Japanese Patent Publication No. 8-20636, etc.

[0029] The softening point of amorphous polyester resin is preferably 90°C or higher, more preferably 100°C or higher, from the viewpoint of durability, and preferably 150°C or lower, more preferably 140°C or lower, from the viewpoint of low-temperature fixability.

[0030] Furthermore, the amorphous polyester resin may be composed of resins with different softening points, from the viewpoint of low-temperature fixability and fixation width. The difference in softening points between the two resins is preferably 10°C or more, more preferably 20°C or more, and preferably 60°C or less, more preferably 50°C or less, and even more preferably 40°C or less.

[0031] The softening point of the amorphous resin (resin AH) with a higher softening point is preferably 100°C or higher, more preferably 110°C or higher, and even more preferably 120°C or higher, from the viewpoint of fixing width, and preferably 180°C or lower, more preferably 160°C or lower, and even more preferably 140°C or lower, from the viewpoint of low-temperature fixing properties.

[0032] Furthermore, the softening point of the amorphous resin (resin AL) with a lower softening point is preferably 70°C or higher, more preferably 90°C or higher, and even more preferably 100°C or higher, from the viewpoint of durability, and preferably 130°C or lower, more preferably 125°C or lower, and even more preferably 120°C or lower, from the viewpoint of low-temperature fixing properties.

[0033] The mass ratio of resin AH to resin AL (resin AH / resin AL) is preferably 10 / 90 or more, more preferably 20 / 80 or more, even more preferably 30 / 70 or more, and preferably 90 / 10 or less, more preferably 80 / 20 or less, and even more preferably 70 / 30 or less.

[0034] The glass transition temperature of amorphous polyester resins is preferably 40°C or higher, more preferably 50°C or higher, from the viewpoint of durability, and preferably 80°C or lower, more preferably 70°C or lower, and even more preferably 65°C or lower, from the viewpoint of low-temperature fixability. When amorphous polyester resins consist of two or more types of resins, it is preferable that the weighted average value is within the above range.

[0035] The acid value of the amorphous polyester resin is preferably 1 mg KOH / g or more, more preferably 3 mg KOH / g or more, from the viewpoint of low-temperature fixability, and preferably 20 mg KOH / g or less, more preferably 15 mg KOH / g or less, from the viewpoint of durability. If the amorphous polyester resin consists of two or more resins, it is preferable that the weighted average value is within the above range.

[0036] The content of amorphous polyester resin in the binder resin is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, and 100% by mass or less, and particularly preferably 100% by mass.

[0037] The ester composition (E) is one or more selected from ester composition (E1) and ester composition (E2). Ester composition (E1) contains a condensate of a carboxylic acid component (E1-ac) containing 55 mol% or more of an aliphatic monocarboxylic acid compound having 10 to 30 carbon atoms, and an alcohol component (E1-al) containing 80 mol% or more of a divalent or higher aliphatic alcohol having 2 to 14 carbon atoms. In the present invention, ester composition (E1) is preferred from the viewpoint of preservation, and ester composition (E2) is preferred from the viewpoint of fixation.

[0038] The carbon number of the aliphatic monocarboxylic acid compound is 10 or more, preferably 12 or more, more preferably 14 or more, and even more preferably 16 or more, from the viewpoint of further improving image density and gloss, and 30 or less, preferably 28 or less, more preferably 26 or less, even more preferably 24 or less, even more preferably 22 or less, and even more preferably 20 or less, from the viewpoint of low-temperature fixability. The carbon number of the alkyl ester portion when the aliphatic monocarboxylic acid compound is an alkyl ester of an aliphatic monocarboxylic acid is not included in the above carbon number.

[0039] The aliphatic monocarboxylic acid compound may be either a saturated aliphatic monocarboxylic acid compound or an unsaturated aliphatic monocarboxylic acid compound, but a saturated aliphatic monocarboxylic acid compound is preferred from the viewpoint of further improving image density and gloss.

[0040] Examples of saturated aliphatic monocarboxylic acid compounds include capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, and montanic acid. Among these, stearic acid or palmitic acid are preferred from the viewpoint of low-temperature fixability and further improvement of image density and gloss.

[0041] The carboxylic acid component (E1-ac) may include other carboxylic acid compounds other than aliphatic monocarboxylic acid compounds. Examples of other carboxylic acid compounds include linear or branched aliphatic dicarboxylic acid compounds, aromatic dicarboxylic acid compounds, alicyclic dicarboxylic acid compounds, and trivalent or higher carboxylic acid compounds.

[0042] The content of the aliphatic monocarboxylic acid compound is 55 mol% or more, preferably 60 mol% or more, more preferably 75 mol% or more, even more preferably 85 mol% or more, even more preferably 95 mol% or more, and 100 mol% or less, and particularly preferably 100 mol%, in the carboxylic acid component (E1-ac) from the viewpoint of further improving image density and gloss.

[0043] The number of carbon atoms in the divalent or higher aliphatic alcohol is 2 or more, preferably 3 or more, from the viewpoint of image density and gloss, and 14 or less, preferably 12 or less, and more preferably 10 or less, from the viewpoint of low-temperature fixability.

[0044] Examples of aliphatic alcohols with a valency of 2 or higher include straight-chain or branched aliphatic diols and aliphatic alcohols with a valency of 3 or higher.

[0045] The linear or branched aliphatic diol may be either a saturated aliphatic diol or an unsaturated aliphatic diol, but a saturated aliphatic diol is preferred from the viewpoint of further improving image density and gloss.

[0046] Examples of saturated aliphatic diols include ethylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,10-decanediol, 1,12-dodecanediol, and 1,14-tetradecanediol.

[0047] Examples of trivalent or higher aliphatic alcohols include glycerin, pentaerythritol, trimethylolpropane, and sorbitol, with glycerin being preferred among these.

[0048] From the viewpoint of pigment dispersibility, aliphatic alcohols with a valency of 3 or higher are preferred over those with a valency of 2 or higher.

[0049] The alcohol component (E1-al) may include alcohols other than dihydric or higher aliphatic alcohols. Examples of other alcohols include monoalcohols, aromatic diols, alicyclic diols, and trihydric or higher aromatic alcohols.

[0050] The content of divalent or higher aliphatic alcohols in the alcohol component (E1-al) is 80 mol% or more, preferably 90 mol% or more, more preferably 95 mol% or more, and 100 mol% or less, and particularly preferably 100 mol%, from the viewpoint of further improving image density and gloss.

[0051] The equivalent ratio (COOH group / OH group) of the carboxyl group of the carboxylic acid component (E1-ac) to the hydroxyl group of the alcohol component (E1-al) is preferably 0.1 or more, more preferably 0.2 or more, even more preferably 0.3 or more, and preferably 2 or less, more preferably 1 or less, and even more preferably 0.7 or less.

[0052] The ester composition (E1) preferably contains a condensate of an aliphatic monocarboxylic acid compound having 10 to 30 carbon atoms and a divalent or higher aliphatic alcohol having 2 to 14 carbon atoms; more preferably contains a condensate of an aliphatic monocarboxylic acid compound having 12 to 26 carbon atoms and a divalent or higher aliphatic alcohol having 2 to 10 carbon atoms; and even more preferably contains a condensate of an aliphatic monocarboxylic acid compound having 14 to 22 carbon atoms and a divalent or higher aliphatic alcohol having 2 to 4 carbon atoms.

[0053] The ester composition (E2) contains a condensate of an alcohol component (E2-al) containing 55 mol% or more of an aliphatic monoalcohol having 10 to 30 carbon atoms, and a carboxylic acid component (E2-ac) containing 80 mol% or more of a divalent or higher aliphatic carboxylic acid compound having 2 to 14 carbon atoms.

[0054] The carbon number of the aliphatic monoalcohol is 10 or more, preferably 12 or more, more preferably 14 or more, even more preferably 16 or more, and even more preferably 18 or more, from the viewpoint of further improving image density and gloss, and from the viewpoint of low-temperature fixability, it is 30 or less, preferably 28 or less, more preferably 26 or less, even more preferably 24 or less, and even more preferably 22 or less.

[0055] The aliphatic monoalcohol may be either a saturated aliphatic monoalcohol or an unsaturated aliphatic monoalcohol. From the viewpoint of further improving image density and gloss, a saturated aliphatic monoalcohol is preferred.

[0056] Examples of aliphatic monoalcohols include capric alcohol, lauryl alcohol, stearyl alcohol, palmityl alcohol, and behenyl alcohol. Of these, stearyl alcohol or behenyl alcohol is preferred, and stearyl alcohol is more preferred.

[0057] The alcohol component (E2-al) may include alcohols other than aliphatic monoalcohols. Examples of other alcohols include linear or branched aliphatic diols, alicyclic diols, and trivalent or higher alcohols.

[0058] The aliphatic monoalcohol content is 55 mol% or more, preferably 60 mol% or more, more preferably 75 mol% or more, even more preferably 85 mol% or more, even more preferably 95 mol% or more, and 100 mol% or less, and particularly preferably 100 mol%, in the alcohol component (E2-al) from the viewpoint of further improving image density and gloss.

[0059] Examples of aliphatic carboxylic acid compounds with a valency of 2 or higher include linear or branched aliphatic dicarboxylic acid compounds and aliphatic carboxylic acid compounds with a valency of 3 or higher.

[0060] The carbon number of the aliphatic carboxylic acid compound with two or more valent properties is 2 or more, preferably 4 or more, and more preferably 6 or more, from the viewpoint of further improving image density and gloss, and 14 or less, preferably 12 or less, from the viewpoint of low-temperature fixability. Note that the carbon number of the alkyl ester portion when the aliphatic carboxylic acid compound with two or more valent properties is an alkyl ester of an aliphatic carboxylic acid is not included in the above carbon number.

[0061] The aliphatic dicarboxylic acid compound may be either a saturated aliphatic dicarboxylic acid compound or an unsaturated aliphatic dicarboxylic acid compound.

[0062] Examples of aliphatic dicarboxylic acid compounds include succinic acid, fumaric acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, tetradecanedioic acid, anhydrides of these acids, and alkyl esters of these acids with 1 to 3 carbon atoms in the alkyl group. Among these, sebacic acid is preferred.

[0063] Examples of aliphatic carboxylic acid compounds with a valency of 3 or higher include aconitic acid, anhydrides of these acids, and alkyl esters of these acids with an alkyl group having 1 to 3 carbon atoms.

[0064] From the viewpoint of low-temperature fixability and further improvement of image density and gloss, saturated aliphatic dicarboxylic acid compounds are preferred among the aliphatic carboxylic acid compounds with a valency of 2 or higher, and sebacic acid is more preferred.

[0065] The carboxylic acid component (E2-ac) may include other carboxylic acid compounds other than aliphatic carboxylic acid compounds with a valency of 2 or higher. Examples of other carboxylic acid compounds include monocarboxylic acid compounds, aromatic dicarboxylic acid compounds, alicyclic dicarboxylic acid compounds, and aromatic carboxylic acid compounds with a valency of 3 or higher.

[0066] The content of divalent or higher aliphatic carboxylic acid compounds in the carboxylic acid component (E2-ac) is 80 mol% or more, preferably 90 mol% or more, more preferably 95 mol% or more, and 100 mol% or less, and particularly preferably 100 mol%, from the viewpoint of further improving image density and gloss.

[0067] The equivalent ratio (COOH group / OH group) of the carboxyl group of the carboxylic acid component (E2-ac) to the hydroxyl group of the alcohol component (E2-al) is preferably 1 or more, more preferably 1.2 or more, even more preferably 1.4 or more, and preferably 10 or less, more preferably 5 or less, and even more preferably 3.3 or less.

[0068] The ester composition (E2) preferably contains a condensate of an aliphatic monoalcohol having 10 to 30 carbon atoms and a divalent or higher aliphatic carboxylic acid compound having 2 to 14 carbon atoms; more preferably contains a condensate of an aliphatic monoalcohol having 12 to 26 carbon atoms and a divalent or higher aliphatic carboxylic acid compound having 2 to 12 carbon atoms; and even more preferably contains a condensate of an aliphatic monoalcohol having 18 to 22 carbon atoms and a divalent or higher aliphatic carboxylic acid compound having 2 to 10 carbon atoms.

[0069] Ester composition (E) can be produced by condensing raw material monomers containing an alcohol component and a carboxylic acid component. For example, ester composition (E1) can be produced by condensing raw material monomers containing an alcohol component (E1-al) and a carboxylic acid component (E1-ac) in an inert gas atmosphere, preferably in the presence of an esterification catalyst, and optionally in the presence of an esterification co-catalyst, polymerization inhibitor, etc., at a temperature preferably 130°C or higher, more preferably 170°C or higher, and preferably 250°C or lower, more preferably 240°C or lower. Ester composition (E2) can be produced in the same manner as ester composition (E1) using raw material monomers containing an alcohol component (E2-al) and a carboxylic acid component (E2-ac).

[0070] The esterification catalyst, esterification co-catalyst, and polymerization inhibitor used in the production of ester composition (E1) and ester composition (E2) are the same as those used in the production of amorphous polyester resins. In the production of ester composition (E1) and ester composition (E2), the amount of esterification catalyst used is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, and preferably 1 part by mass or less, and more preferably 0.5 parts by mass or less, per 100 parts by mass of raw material monomer. The amount of esterification co-catalyst used is preferably 0.001 parts by mass or more, more preferably 0.01 parts by mass or more, and preferably 0.5 parts by mass or less, and more preferably 0.1 parts by mass or less, per 100 parts by mass of raw material monomer. The amount of polymerization inhibitor used is preferably 0.001 parts by mass or more, more preferably 0.01 parts by mass or more, and preferably 0.5 parts by mass or less, and more preferably 0.1 parts by mass or less, per 100 parts by mass of raw material monomer.

[0071] The sum of the acid value and hydroxyl value of the ester composition (E) is, from the viewpoint of pigment dispersibility, 70 mg KOH / g or more, preferably 80 mg KOH / g or more, more preferably 90 mg KOH / g or more, and even more preferably 95 mg KOH / g or more, and from the viewpoint of preservation, 400 mg KOH or less, preferably 380 mg KOH / g or less, more preferably 350 mg KOH / g or less, and even more preferably 320 mg KOH / g or less.

[0072] From the viewpoint of preservation, the acid value of the ester composition (E1) is preferably 0.1 mg KOH / g or more, more preferably 0.5 mg KOH / g or more, and preferably 40 mg KOH / g or less, more preferably 20 mg KOH / g or less, and even more preferably 5 mg KOH / g or less.

[0073] The hydroxyl value of the ester composition (E1) is preferably 30 mg KOH / g or more, more preferably 70 mg KOH / g or more, even more preferably 80 mg KOH / g or more, and even more preferably 90 mg KOH / g or more, from the viewpoint of pigment dispersibility, and preferably 400 mg KOH or less, more preferably 360 mg KOH / g or less, and even more preferably 320 mg KOH / g or less, from the viewpoint of preservation.

[0074] The acid value of the ester composition (E2) is preferably 80 mg KOH / g or more, more preferably 90 mg KOH / g or more, and even more preferably 100 mg KOH / g or more, from the viewpoint of pigment dispersibility, and preferably 200 mg KOH / g or less, more preferably 180 mg KOH / g or less, and even more preferably 160 mg KOH / g or less, from the viewpoint of preservation.

[0075] From the viewpoint of preservation, the hydroxyl value of the ester composition (E2) is preferably 0.1 mg KOH / g or more, more preferably 0.5 mg KOH / g or more, and preferably 20 mg KOH / g or less, more preferably 10 mg KOH / g or less, and even more preferably 5 mg KOH / g or less.

[0076] The weight-average molecular weight of the ester composition (E) is preferably 100 or more, more preferably 150 or more, and even more preferably 200 or more, from the viewpoint of further improving image density and gloss, and preferably 2,000 or less, more preferably 1,500 or less, and even more preferably 1,000 or less, from the viewpoint of low-temperature fixability.

[0077] The softening point of the ester composition (E) is preferably 40°C or higher, more preferably 50°C or higher, even more preferably 60°C or higher, and preferably 90°C or lower, more preferably 80°C or lower, and even more preferably 70°C or lower.

[0078] The ester composition (E) is preferably a crystalline composition having a melting point, and the crystallinity index, defined by the value of [softening point / maximum endothermic peak temperature], is 0.6 or higher, preferably 0.7 or higher, more preferably 0.9 or higher, and more preferably 1.4 or lower, preferably 1.2 or lower, more preferably 1.1 or lower.

[0079] The melting point of the ester composition (E) is preferably 30°C or higher, more preferably 40°C or higher, and even more preferably 50°C or higher, from the viewpoint of preservation, and preferably 90°C or lower, more preferably 80°C or lower, and even more preferably 70°C or lower, from the viewpoint of fixation.

[0080] The acid value, hydroxyl value, weight-average molecular weight, softening point, and melting point of the ester composition (E) can be appropriately adjusted depending on the type and ratio of the raw material monomers, as well as the manufacturing conditions such as the reaction temperature, reaction time, and cooling rate. When two or more types of ester compositions (E) are used in combination, it is preferable that the physical properties obtained from the mixture thereof are within the aforementioned ranges.

[0081] In the toner of the present invention, the content of the ester compound (E) is preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 3% by mass or more, in the total amount of the binder resin and the ester compound (E), from the viewpoint of improving the dispersibility of the colorant and further improving image density and gloss, and from the viewpoint of storage, preferably 15% by mass or less, more preferably 10% by mass or less, and even more preferably 7% by mass or less.

[0082] The total content of the binder resin and ester composition (E) in the toner is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and preferably less than 100% by mass, more preferably 98% by mass or less, and even more preferably 95% by mass or less.

[0083] The coloring agent may be either a pigment or a dye, but a pigment is preferred from the viewpoint of significantly improving the dispersibility of the coloring agent. Examples of pigments include azo pigments, phthalocyanine pigments, condensed polycyclic pigments, and lake pigments. Examples of azo pigments include insoluble azo pigments such as CI Pigment Red 3, soluble azo pigments such as CI Pigment Red 48:1, and condensed azo pigments such as CI Pigment Red 144. Examples of phthalocyanine pigments include copper phthalocyanine pigments such as CI Pigment Blue 15:3 and zinc halide phthalocyanine pigments such as CI Pigment Green 58. Examples of condensed polycyclic pigments include anthraquinone pigments such as CI Pigment Red 177, perylene pigments such as CI Pigment Red 123, perinone pigments such as CI Pigment Orange 43, quinacridone pigments such as CI Pigment Red 122, naphthol pigments such as CI Pigment Red 269, dioxazine pigments such as CI Pigment Violet 23, isoindolinone pigments such as CI Pigment Yellow 139 and 185, isoindoline pigments such as CI Pigment Orange 66, quinophthalone pigments such as CI Pigment Yellow 138, nickel azo complex pigments such as CI Pigment Yellow 150, indigo pigments such as CI Pigment Red 88, metal complex pigments such as CI Pigment Green 8, and diketopyrrolopyrrole pigments such as CI Pigment Red 254, CI Pigment Red 255, and CI Pigment Orange 71. Examples of lake pigments include CI Pigment Red 57:1. Among these, from the viewpoint of color development and image scratch resistance, azo pigments, quinacridone pigments, isoindolinone pigments, naphthol pigments, anthraquinone pigments, or lake pigments are preferred, naphthol pigments, quinacridone pigments, or isoindolinone pigments are more preferred, and naphthol pigments or isoindolinone pigments are even more preferred. Two or more of these pigments may be used in combination.

[0084] From the viewpoint of improving the toner's image density and low-temperature fixability, the colorant content is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and preferably 40 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less, based on 100 parts by mass of the total of the binder resin and ester composition (E).

[0085] In addition to the binder resin, ester composition (E), and colorant, the toner of the present invention may also contain additives such as a mold release agent, charge control agent, magnetic powder, flowability improver, conductivity modifier, reinforcing filler such as a fibrous material, antioxidant, and cleaning performance improver.

[0086] Examples of mold release agents include hydrocarbon waxes and their oxides, such as polypropylene wax, polyethylene wax, polypropylene-polyethylene copolymer wax, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax; ester waxes such as carnauba wax, montane wax and their deoxidizing waxes, and fatty acid ester waxes; and fatty acid amides, fatty acids, higher alcohols, fatty acid metal salts, etc., which can be used individually or in combination of two or more.

[0087] The melting point of the release agent is preferably 60°C or higher, more preferably 70°C or higher, from the viewpoint of durability, and preferably 160°C or lower, more preferably 140°C or lower, even more preferably 120°C or lower, and even more preferably 110°C or lower, from the viewpoint of low-temperature fixation.

[0088] The amount of release agent is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 1.5 parts by mass or more, and preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and even more preferably 7 parts by mass or less, based on 100 parts by mass of the total of the binder resin and the ester composition (E), from the viewpoint of the low-temperature fixability and durability of the toner and dispersibility in the binder resin.

[0089] The charge control agent is not particularly limited and may contain either a positively charged charge control agent or a negatively charged charge control agent.

[0090] Positively charged charge control agents include nigrosine dyes, such as "Nigrosine Base EX," "Oil Black BS," "Oil Black SO," "Bontron N-01," "Bontron N-04," "Bontron N-07," "Bontron N-09," and "Bontron N-11" (all manufactured by Orient Chemical Industries, Ltd.); triphenylmethane-based dyes containing tertiary amines as side chains; quaternary ammonium salt compounds, such as "Bontron P-51" (manufactured by Orient Chemical Industries, Ltd.), cetyltrimethylammonium bromide, and "COPY CHARGE PX." Examples include VP435 (manufactured by Clariant), polyamine resins such as AFP-B (manufactured by Orient Chemical Industries, Ltd.), imidazole derivatives such as PLZ-2001 and PLZ-8001 (both manufactured by Shikoku Chemicals, Ltd.), and styrene-acrylic resins such as FCA-701PT and FCA-201-PS (manufactured by Fujikura Chemicals, Ltd.).

[0091] Furthermore, as negative charge control agents, metal-containing azo dyes, such as "Barifast Black 3804," "Bontron S-31," "Bontron S-32," "Bontron S-34," and "Bontron S-36" (all manufactured by Orient Chemical Industries, Ltd.), "Eisenspiron Black TRH," and "T-77" (manufactured by Hodogaya Chemical Co., Ltd.); metal compounds of benzyl acid compounds, such as "LR-147" and "LR-297" (both manufactured by Nippon Carlit Co., Ltd.); metal compounds of salicylic acid compounds, such as "Bontron E-81," "Bontron E-84," "Bontron E-88," and "Bontron E-304" (all manufactured by Orient Chemical Industries, Ltd.), and "TN-105" (manufactured by Hodogaya Chemical Co., Ltd.); copper phthalocyanine dyes; and quaternary ammonium salts, such as "COPY CHARGE NX" Examples include VP434 (manufactured by Clariant), nitroimidazole derivatives, organometallic compounds, etc.

[0092] From the viewpoint of the charge stability of the toner, the content of the charge control agent is preferably 0.01 parts by mass or more, more preferably 0.2 parts by mass or more, and preferably 10 parts by mass or less, more preferably 5 parts by mass or less, even more preferably 3 parts by mass or less, and even more preferably 2 parts by mass or less, based on 100 parts by mass of the total of the binder resin and ester composition (E).

[0093] The toner of the present invention may be obtained by any of the conventionally known methods, such as the melt-kneading method, the emulsification-phase inversion method, or the polymerization method. However, a pulverized toner obtained by the melt-kneading method is preferred because it exhibits a more pronounced effect in improving the dispersibility of the colorant.

[0094] Therefore, the toner of the present invention is preferably manufactured by a method comprising the steps of: melting and kneading a mixture containing a binder resin, an ester composition (E), a colorant, and optionally additives such as a mold release agent and a charge control agent to obtain a melted mixture (melt kneading step); and crushing and classifying the melted mixture to obtain toner particles (crushing and classification step).

[0095] The mixture to be subjected to melting and kneading may be kneaded all at once or in portions, but it is preferable to mix it beforehand in a mixer such as a Henschel mixer or ball mill before supplying it to the kneader.

[0096] Melt mixing can be carried out using known mixing machines such as closed-type kneaders, single-screw or twin-screw extruders, and open-roll type mixers.

[0097] The melting and mixing temperature is not particularly limited as long as it is the temperature at which the resin components melt and mix together.

[0098] After the melt-kneading process, it is preferable to cool the kneaded material appropriately until it reaches a hardness that allows for pulverization, and then, if necessary, perform a pulverization process and a classification process to obtain toner particles. Here, cooling refers to cooling the kneaded material to a temperature between 0°C and 50°C, or to a temperature below the glass transition temperature of the binder resin in the kneaded material.

[0099] The grinding and classification processes can be carried out as appropriate using conventional methods. In the grinding process, the kneaded material may be ground all at once to the desired particle size, or it may be ground in stages. In the classification process, any ground material that has been removed due to insufficient grinding may be subjected to the grinding process again, and the grinding and classification processes may be repeated as needed.

[0100] In order to improve the transferability of the toner of the present invention, it is preferable to use external additives. Examples of external additives include inorganic fine particles such as silica, alumina, titania, zirconia, tin oxide, and zinc oxide, and organic fine particles such as melamine resin fine particles and polytetrafluoroethylene resin fine particles, and two or more types may be used in combination. Among these, silica is preferred, and from the viewpoint of the transferability of the toner, hydrophobic silica that has been hydrophobized is more preferred.

[0101] Examples of hydrophobic agents used to hydrophobize the surface of silica particles include hexamethyldisilazane (HMDS), dimethyldichlorosilane (DMDS), silicone oil, octyltriethoxysilane (OTES), and methyltriethoxysilane.

[0102] The average particle size of the external additive is preferably 10 nm or larger, more preferably 15 nm or larger, and more preferably 250 nm or smaller, more preferably 200 nm or smaller, and even more preferably 90 nm or smaller, from the viewpoint of the toner's chargeability, fluidity, and transferability.

[0103] From the viewpoint of the toner's electrostatic properties, fluidity, and transferability, the content of the external additive is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, even more preferably 0.3 parts by mass or more, and preferably 5 parts by mass or less, and more preferably 3 parts by mass or less, per 100 parts by mass of toner particles before treatment with the external additive.

[0104] The volume-intermediate particle size (D) of the toner of the present invention 50The volume median particle size (D) is preferably 3 μm or more, more preferably 4 μm or more, and preferably 15 μm or less, more preferably 10 μm or less. 50 ) refers to the particle size at which the cumulative volume frequency calculated using volume fractions accounts for 50% when calculated from the smallest particle size. Furthermore, if the toner is treated with an external additive, the volume median particle size of the toner particles before treatment with the external additive is taken as the volume median particle size of the toner.

[0105] The toner of the present invention can be used as is as a one-component developing toner, or as a two-component developing toner mixed with a carrier, in image forming apparatuses using either a one-component developing method or a two-component developing method, respectively. [Examples]

[0106] The present invention will be specifically described below with reference to examples, but the present invention is not limited in any way by these examples. The physical properties of resins, etc., can be measured by the following methods.

[0107] [Softening point of resins and ester compositions] Using a flow tester "CFT-500D" (manufactured by Shimadzu Corporation), 1 g of sample is heated at a heating rate of 6°C / min while a load of 1.96 MPa is applied by a plunger, and the sample is extruded from a nozzle with a diameter of 1 mm and a length of 1 mm. The amount of plunger descent of the flow tester is plotted against temperature, and the temperature at which half of the sample has flowed out is defined as the softening point.

[0108] [Maximum peak temperature of endothermic resin] Using a differential scanning calorimeter "Q-20" (manufactured by T.A. Instruments Japan Co., Ltd.), a sample cooled from room temperature (20°C) to 0°C at a rate of 10°C / min was maintained at that temperature for 1 minute, and then the heat quantity was measured while the temperature was increased to 180°C at a rate of 10°C / min. Among the observed endothermic peaks, the temperature of the peak with the largest peak area was defined as the maximum endothermic peak temperature.

[0109] [Glass transition temperature of resins] Using a differential scanning calorimeter "Q-20" (manufactured by T.A. Instruments Japan Co., Ltd.), 0.01 to 0.02 g of the sample is weighed into an aluminum pan, heated to 200°C, and then cooled to 0°C at a rate of 10°C / min. Next, the sample is heated at a rate of 10°C / min, and the temperature at the intersection of the extension of the baseline below the maximum endothermic peak temperature and the tangent line showing the maximum slope from the rise of the peak to the peak apex is defined as the glass transition temperature.

[0110] [Acid value of resins] The measurement will be performed according to the method of JIS K0070:1992. However, the measurement solvent will be changed from the mixed solvent of ethanol and ether specified in JIS K0070:1992 to a mixed solvent of acetone and toluene (acetone:toluene = 1:1 (volume ratio)).

[0111] [Maximum peak temperature (melting point) of endothermic ester composition] Using a differential scanning calorimeter "Q-100" (manufactured by T.A. Instruments Japan Co., Ltd.), a sample cooled from room temperature (20°C) to 0°C at a rate of 10°C / min was maintained at that temperature for 1 minute, and then the heat quantity was measured while the temperature was increased to 180°C at a rate of 10°C / min. Among the observed endothermic peaks, the temperature of the peak with the largest peak area was defined as the maximum endothermic peak temperature and was defined as the melting point.

[0112] [Acid value and hydroxyl value of ester compositions] The measurement will be performed according to the method of JIS K0070:1992. However, the measurement solvent will be changed from the mixed solvent of ethanol and ether specified in JIS K0070:1992 to chloroform.

[0113] [Weight-average molecular weight of ester compositions] The molecular weight distribution is measured by gel permeation chromatography (GPC), obtained by the following method, and the weight-average molecular weight is determined. (1) Preparation of sample solution Dissolve the sample in chloroform at 25 °C so that the concentration becomes 0.5 g / 100 mL. Then, filter this solution using a fluororesin filter "FP-200" with a pore size of 2 μm (manufactured by Sumitomo Electric Industries, Ltd.) to remove insoluble matter, and obtain a sample solution. (2) Molecular weight measurement Using the following measuring device and analytical column, flow chloroform as an eluent at a flow rate of 1 mL per minute, and stabilize the column in a thermostat at 40 °C. Inject 100 μL of the sample solution there and conduct the measurement. The molecular weight of the sample was calculated based on a calibration curve prepared in advance. For this calibration curve, several types of monodisperse polystyrenes "A-500" (5.0×10 2 ), "A-1000" (1.01×10 3 ), "A-2500" (2.63×10 3 ), "A-5000" (5.97×10 3 ), "F-1" (1.02×10 4 ), "F-2" (1.81×10 4 ), "F-4" (3.97×10 4 ), "F-10" (9.64×10 4 ), "F-20" (1.90×10 5 ), "F-40" (4.27×10 5 ), "F-80" (7.06×10 5 ), "F-128" (1.09×10 6 ) (all manufactured by Tosoh Corporation) were used as standard samples. The values in parentheses indicate the molecular weights. Measuring device: "CO-8010" (manufactured by Tosoh Corporation) Analytical column: "GMHXL" + "G3000HXL" (manufactured by Tosoh Corporation)

[0114] 〔Melting point of the mold release agent〕 Using a differential scanning calorimeter "DSC Q-100" (manufactured by T.A. Instruments Japan Co., Ltd.), 0.01 to 0.02 g of the sample is weighed into an aluminum pan, heated to 200°C at a heating rate of 10°C / min, and then cooled to -10°C at a cooling rate of 5°C / min. Next, the sample is heated to 180°C at a heating rate of 10°C / min and measured. The maximum endothermic peak temperature observed from the resulting melting endothermic curve is defined as the melting point of the wax.

[0115] [Average particle size of external additives] The average particle diameter refers to the number-average particle diameter, which is calculated by measuring the particle size (average of the major and minor axes) of 500 particles from scanning electron microscope (SEM) images and using the number-average value of these measurements.

[0116] [Medium particle size in toner volume] • Measuring instrument: Coulter Multisizer III (manufactured by Beckman Coulter, Inc.) • Aperture diameter: 50 μm • Analysis software: Multisizer III version 3.51 (manufactured by Beckman Coulter, Inc.) • Electrolyte: "Isoton (registered trademark) II" (manufactured by Beckman Coulter, Inc.) • Dispersion: Prepared by dissolving polyoxyethylene lauryl ether "Emulgen (registered trademark) 109P" [manufactured by Kao Corporation, HLB (Griffin) = 13.6] in the electrolyte to adjust the concentration to 5% by mass. • Dispersion conditions: Add 10 mg of the sample to 5 mL of the dispersion and disperse for 1 minute using an ultrasonic disperser (machine name: US-1 manufactured by SND Corporation, output: 80W). Then, add 25 mL of electrolyte and disperse for another minute using the ultrasonic disperser to prepare the sample dispersion. • Measurement conditions: The sample dispersion is added to 100 mL of the electrolyte to adjust the concentration so that the particle size of 30,000 particles can be measured in 20 seconds. Then, the 30,000 particles are measured, and the volume median particle size (D) is determined from the particle size distribution. 50 )

[0117] Resin manufacturing example 1 The raw material monomers and esterification catalyst shown in Table 1 were placed in a 20-liter four-necked flask equipped with a thermometer, stainless steel stirring rod, a drop-through condenser, and a nitrogen inlet tube. The mixture was heated to 235°C over 2 hours in a mantle heater under a nitrogen atmosphere. After confirming that the reaction rate reached over 90% at 235°C, the reaction was carried out under reduced pressure of 40 kPa at 235°C until the desired softening point was reached, yielding an amorphous polyester resin (resin A1). The physical properties of the obtained resin are shown in Table 1.

[0118] Resin manufacturing example 2 Of the raw material monomers shown in Table 1, all raw material monomers except trimellitic anhydride and the esterification catalyst were placed in a 20-liter four-necked flask equipped with a thermometer, stainless steel stirring rod, drop-through condenser, and nitrogen inlet tube. The mixture was heated to 235°C over 2 hours in a mantle heater under a nitrogen atmosphere. After confirming that the reaction rate reached over 90% at 235°C, the mixture was cooled to 190°C, trimellitic anhydride (shown in Table 1) was added, and the mixture was heated to 210°C over 2 hours. After reacting at 210°C for 1 hour, the reaction was carried out under reduced pressure of 40 kPa until the desired softening point was reached, yielding an amorphous polyester resin (resin B1). The physical properties of the obtained resin are shown in Table 1.

[0119] [Table 1]

[0120] Examples of ester composition production The alcohol and carboxylic acid components shown in Tables 2-4 were placed in a 10-liter four-necked flask equipped with a thermometer, stainless steel stirring rod, fall-flow condenser, and nitrogen inlet tube. The mixture was heated in a mantle heater under a nitrogen atmosphere from 130°C to 200°C over 8 hours, then reacted at 200°C for 2 hours. After that, the esterification catalyst was added, and the reaction was carried out under reduced pressure of 8 kPa until the desired softening point was reached to obtain ester compositions (ester compositions E1-1 to E1-10, E2-1, E2-2). The physical properties of the obtained compositions are shown in Tables 2-4.

[0121] [Table 2]

[0122] [Table 3]

[0123] [Table 4]

[0124] Examples 1-12 and Comparative Examples 1 and 2 The resin components in the proportions shown in Table 5 totaled 100 parts by mass, the negative charge control agent "Bontron E-81" (manufactured by Orient Chemical Industry Co., Ltd.) 1 part by mass, and the coloring agent (magenta pigment "Permanent") shown in Table 5. Ten parts by mass of either "Carmine 3810" (manufactured by Sanyo Pigment Co., Ltd., Pigment Red 269) or the yellow pigment "Paliotoll Yellow D1155" (manufactured by BASF, Pigment Yellow 185), and two parts by mass of the release agent "HNP-9" (manufactured by Nippon Seiro Co., Ltd., paraffin wax, melting point: 80°C) were thoroughly mixed in a Henschel mixer. Then, using a twin-screw extruder with a total length of 1560 mm in the mixing section, a screw diameter of 42 mm, and a barrel inner diameter of 43 mm, the mixture was melt-kneaded at a screw rotation speed of 200 r / min and a barrel setting temperature of 100°C. The feed rate of the mixture was 20 kg / h, and the average residence time was approximately 18 seconds. The obtained molten mixture was cooled and coarsely ground, then ground in a jet mill and classified to obtain the medium particle size (D 50 ) yielded toner particles with a diameter of 8 μm.

[0125] To 100 parts by mass of the obtained toner particles, 1 part by mass of hydrophobic silica "AEROSIL NAX 50" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic treatment agent: HMDS, average particle size: approximately 30 nm) was added as an external additive and mixed in a Henschel mixer to perform the external additive treatment and obtain toner.

[0126] Test Example 1 [Image Density] Using high-quality paper "J Paper A4 size" (manufactured by Fuji Xerox Co., Ltd.) and a commercially available printer "Microline® 5400" (manufactured by OKI Data Corporation), the amount of toner adhering to the paper was 0.25-0.30 mg / cm². 2 A solid image was output, and a printed copy was obtained. Next, the fuser temperature was set to 150°C, and the toner was fixed at a rate of 1.5 seconds per sheet in the A4 portrait direction to obtain the printed material. The reflective image density of the fixed image portion of the printed output was measured using a colorimeter "SpectroEye" (manufactured by GretagMacbeth, light emission conditions: standard light source D). 50 Measurements were taken using a 2° field of view, DINNB density standard, and absolute white standard. A higher reflected image density value indicates better image density. The results are shown in Table 5.

[0127] Test Example 2 [Abrasion Resistance] The evaluation paper used was "Business4200" (weighing capacity 105g / m²). 2 Using a Xerox printer, the toner application rate was 0.50 mg / cm². 2 The solid image was fixed by passing it through a fuser machine heated to 180°C. The resulting fixed image was left for one month in an environment of 40°C and 80% relative humidity. After that, the fixed image was rubbed back and forth five times with a 15mm x 7.5mm sand eraser with a 500g load applied. The optical reflectance density before and after rubbing was measured using a reflectance densitometer "RD-915" (Macbeth Corporation), and the decrease rate (%) of the optical reflectance density was calculated using the following formula. The abrasion resistance of the fixed image was evaluated according to the following evaluation criteria. The results are shown in Table 5.

[0128] Percentage decrease in optical reflectance = [1 - (Optical reflectance after abrasion / Optical reflectance before abrasion)] × 100

[0129] [Evaluation Criteria] A: The decrease in optical reflectance is less than 15%, and no image changes due to abrasion are observed. B: The decrease in optical reflectance is between 15% and 20%, and slight blurring or smudging is visible in the image due to abrasion. C: The decrease in optical reflectance is between 20% and 25%, and the image shows blurring or other imperfections due to abrasion. D: The decrease in optical reflectance is 25% or more, and clear image defects are observed due to abrasion.

[0130] [Table 5]

[0131] From the above results, it can be seen that the toners of Examples 1 to 12 have higher image density and better scratch resistance compared to Comparative Examples 1 and 2. In contrast, in Comparative Example 1, where the sum of the acid value and hydroxyl value of the ester composition was small, the image density was low and the scratch resistance was insufficient, while in Comparative Example 2, which used an ester composition that did not use a monovalent monomer, the decrease in image density was significant. [Industrial applicability]

[0132] The electrostatic image developing toner of the present invention is suitably used for developing latent images formed in electrostatic image developing methods, electrostatic recording methods, electrostatic printing methods, and the like.

Claims

1. A toner for developing electrostatic images containing a binder resin, an ester composition (E), and a colorant, wherein the ester composition (E) is An ester composition (E1) containing a condensate of a carboxylic acid component (E1-ac) containing 55 mol% or more of an aliphatic monocarboxylic acid compound having 10 to 30 carbon atoms, and an alcohol component (E1-al) containing 80 mol% or more of a divalent or higher aliphatic alcohol having 2 to 14 carbon atoms, and An ester composition (E2) containing a condensate of an alcohol component (E2-al) containing 55 mol% or more of an aliphatic monoalcohol having 10 to 30 carbon atoms, and a carboxylic acid component (E2-ac) containing 80 mol% or more of a divalent or higher aliphatic carboxylic acid compound having 2 to 14 carbon atoms. One or more types selected from, A toner for developing electrostatic images, wherein the sum of the acid value and hydroxyl value of the ester composition (E) is 70 mg KOH / g or more and 400 mg KOH or less, the acid value of the ester composition (E1) is 0.1 mg KOH / g or more and 40 mg KOH / g or less, and the hydroxyl value is 30 mg KOH / g or more and 360 mg KOH or less, and the acid value of the ester composition (E2) is 80 mg KOH / g or more and 200 mg KOH / g or less, and the hydroxyl value is 0.1 mg KOH / g or more and 20 mg KOH / g or less.

2. The electrostatic image developing toner according to claim 1, wherein the ester composition (E) is the ester composition (E1).

3. The electrostatic image developing toner according to claim 1, wherein the ester composition (E) is ester composition (E2).

4. The toner for developing electrostatic images according to claim 2, wherein the hydroxyl value of the ester composition (E1) is 70 mg KOH / g or more and 360 mg KOH or less.

5. The toner for developing electrostatic images according to claim 1, wherein the weight-average molecular weight of the ester composition (E) is 2,000 or less.

6. The toner for developing electrostatic images according to claim 1, wherein the ester composition (E) is a crystalline ester composition having a melting point, and the melting point is 30°C or higher and 90°C or lower.

7. The toner for developing electrostatic images according to claim 1, wherein the binder resin contains an amorphous polyester resin.

8. The toner for developing electrostatic images according to claim 1, wherein the content of the ester compound (E) is 0.5% by mass or more and 15% by mass or less of the total amount of the binder resin and the ester compound (E).

9. The toner for developing electrostatic images according to claim 1, wherein the coloring agent is a pigment.

10. The electrostatic image developing toner according to claim 9, wherein the pigment is at least one selected from the group consisting of azo pigments, quinacridone pigments, isoindolinone pigments, naphthol pigments, anthraquinone pigments, and lake pigments.

11. A method for producing electrostatic image developing toner according to any one of claims 1 to 10, comprising the steps of: melting and kneading a mixture containing a binder resin, an ester composition (E), and a colorant to obtain a molten kneaded product; and crushing and classifying the molten kneaded product to obtain toner particles.

Images