Electrostatic image developing toner

Abstract

To provide an electrostatic image developing toner which is superior in terms of heat-resistant storage stability and low-temperature fixability after storage.SOLUTION: An electrostatic image developing toner containing a crystalline polyester resin C and an amorphous resin A is provided, the crystalline polyester resin C being a polycondensate of an alcohol component, a carboxylic acid component, and a polyamide compound and having a melting point in the range of 50°C to 140°C, inclusive.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a toner for developing electrostatic images used in developing latent images formed in electrophotography, electrostatic recording, electrostatic printing, and the like. [Background technology]

[0002] Patent Document 1 discloses an invention relating to a toner containing a high-melting crystalline polymer and an amorphous polyester, which is excellent in low-temperature fixing property, high-temperature offset resistance, and blocking resistance, and is capable of good color development. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-189808 Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, the low-temperature fixability and heat-resistant storage stability of a toner are contradictory properties, and there is a trade-off relationship in which if one is excellent, the other is inferior, so it is difficult to achieve both. In order to improve the low-temperature fixability of the toner, a crystalline polyester resin with a relatively low melting point is used, but because of its low melting point, it partially melts during storage, which poses a problem of deterioration in the heat-resistant storage stability of the toner and the low-temperature fixability over time. Even with the technology of Patent Document 1, there is room for improvement in the low-temperature fixability after storage.

[0005] The present invention relates to a toner for developing electrostatic images, which has excellent heat-resistant storage stability and low-temperature fixability after storage. [Means for solving the problem]

[0006] The present invention relates to a toner for developing electrostatic images, which contains a crystalline polyester resin C and an amorphous resin A, wherein the crystalline polyester resin C is a polycondensate of an alcohol component, a carboxylic acid component, and a polyamide compound, and the melting point of the crystalline polyester resin C is 50°C or higher and 140°C or lower. [Effects of the Invention]

[0007] The toner for developing electrostatic images of the present invention exhibits excellent effects in terms of heat-resistant storage stability and low-temperature fixability after storage. DETAILED DESCRIPTION OF THE INVENTION

[0008] The electrostatic image developing toner of the present invention (hereinafter also simply referred to as "toner") contains an amorphous resin A and a crystalline polyester resin C having a specific melting point, and has a major characteristic in that the crystalline polyester resin C is obtained using a polyamide compound. The reason why the toner of the present invention has excellent heat-resistant storage stability and low-temperature fixability after storage is not clear, but is presumed as follows. Note that the following mechanism is presumed and is not limited thereto.

[0009] The toner of the present invention contains a crystalline polyester resin C, which is a polycondensate of an alcohol component, a carboxylic acid component, and a polyamide compound. Generally, amide bonds have a higher cohesive strength than ester bonds, and thus introducing a polyamide compound segment into the crystalline polyester resin improves the cohesive strength between the crystalline polyester resins. As a result, crystallization of the crystalline polyester resin is promoted, and the resulting crystalline domains are stabilized over time. In the present invention, even for crystalline polyester resins with melting points in a relatively low temperature range (50°C or higher and 140°C or lower) that is advantageous for low-temperature fixability, the state of the crystalline domains stabilizes during storage, resulting in a toner with excellent heat-resistant storage stability and excellent low-temperature fixability after storage.

[0010] The crystalline polyester resin C is a polycondensate of an alcohol component, a carboxylic acid component, and a polyamide compound.

[0011] From the viewpoint of durability, the alcohol component preferably contains an aliphatic diol.

[0012] Examples of aliphatic diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-butenediol, 1,7-heptanediol, 1,8-octanediol, neopentyl glycol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, and 1,12-dodecanediol.

[0013] The aliphatic diol has 2 or more carbon atoms, preferably 4 or more carbon atoms, and from the viewpoint of low-temperature fixability, preferably 14 or less, more preferably 12 or less, and even more preferably 10 or less carbon atoms.

[0014] From the viewpoint of improving the low-temperature fixability of the toner, the aliphatic diol preferably has a hydroxyl group at the end of the carbon chain, and is more preferably an α,ω-straight-chain alkanediol.

[0015] The content of the aliphatic diol in the alcohol component is preferably 80 mol % or more, more preferably 90 mol % or more, and even more preferably 95 mol % or more, and 100 mol % or less.

[0016] Examples of alcohol components other than aliphatic diols include alkylene oxide adducts of bisphenol A, aromatic diols such as bisphenol A, hydrogenated bisphenol A, trihydric or higher alcohols such as sorbitol, pentaerythritol, glycerin, and trimethylolpropane.

[0017] From the viewpoint of durability, the carboxylic acid component preferably contains an aliphatic dicarboxylic acid compound.

[0018] Examples of the aliphatic dicarboxylic acid compound include succinic acid (number of carbon atoms: 4), fumaric acid (number of carbon atoms: 4), adipic acid (number of carbon atoms: 6), suberic acid (number of carbon atoms: 8), azelaic acid (number of carbon atoms: 9), sebacic acid (number of carbon atoms: 10), dodecanedioic acid (number of carbon atoms: 12), tetradecanedioic acid (number of carbon atoms: 14), anhydrides of these acids, and alkyl esters of these acids having 1 to 3 carbon atoms.

[0019] The carbon number of the aliphatic dicarboxylic acid compound is preferably 4 or more, more preferably 6 or more, and even more preferably 8 or more, and from the viewpoint of low-temperature fixability, is preferably 14 or less, more preferably 12 or less. When the aliphatic dicarboxylic acid compound is an alkyl ester, the carbon number of the alkyl group is not included in the above carbon number.

[0020] The content of the aliphatic dicarboxylic acid compound in the carboxylic acid component is preferably 80 mol % or more, more preferably 90 mol % or more, and 100 mol % or less.

[0021] Examples of other carboxylic acid components include aromatic dicarboxylic acid compounds such as phthalic acid, isophthalic acid, and terephthalic acid, and trivalent or higher carboxylic acid compounds such as trimellitic acid and pyromellitic acid.

[0022] From the viewpoint of hydrophobicity, the alcohol component and / or the carboxylic acid component of the crystalline polyester resin C preferably further contains a monofunctional monomer.

[0023] Examples of monofunctional monomers contained in the alcohol component include aliphatic monoalcohols such as capryl alcohol, lauryl alcohol, myristyl alcohol, palmityl alcohol, stearyl alcohol, and behenyl alcohol.

[0024] The carbon number of the aliphatic monoalcohol is preferably 10 or more, more preferably 12 or more, and even more preferably 14 or more, from the viewpoint of hydrophobicity, and is preferably 22 or less, more preferably 20 or less, and even more preferably 18 or less, from the viewpoint of low-temperature fixability.

[0025] Examples of monofunctional monomers contained in the carboxylic acid component include aliphatic monocarboxylic acids such as capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, and behenic acid, and aliphatic monocarboxylic acid compounds such as alkyl esters of these acids in which the alkyl group has 1 to 3 carbon atoms.

[0026] From the viewpoint of hydrophobicity, the carbon number of the aliphatic monocarboxylic acid compound is preferably 10 or more, more preferably 12 or more, and even more preferably 14 or more, and from the viewpoint of low-temperature fixability, it is preferably 22 or less, more preferably 20 or less, and even more preferably 18 or less. When the aliphatic monocarboxylic acid compound is an alkyl ester, the carbon number of the alkyl group is not included in the above carbon number.

[0027] The content of the monofunctional monomer is preferably 1 mol% or more, more preferably 3 mol% or more, and even more preferably 5 mol% or more of the total amount of the alcohol component and the carboxylic acid component, and from the viewpoint of low-temperature fixability, it is preferably 30 mol% or less, more preferably 20 mol% or less, and even more preferably 15 mol% or less.

[0028] In this specification, macromonomers and hydroxycarboxylic acids are not included in the alcohol component and carboxylic acid component.

[0029] The equivalent ratio of the carboxyl groups of the carboxylic acid component to the hydroxyl groups of the alcohol component (COOH groups / OH groups) is preferably 0.8 or more, more preferably 0.9 or more, from the viewpoint of charging stability, and is preferably 1.2 or less, more preferably 1.1 or less, from the viewpoint of low-temperature fixability.

[0030] Examples of the polyamide compound include a polycondensation product of a diamine and a dicarboxylic acid (dibasic acid), a ring-opening polymerization product of a lactam, and a polycondensation product of an aminocarboxylic acid.

[0031] Examples of the diamine include aliphatic diamines and aromatic diamines.

[0032] Examples of the aliphatic diamine include tetramethylenediamine, hexamethylenediamine, octamethylenediamine, nonamethylenediamine, undecamethylenediamine, and dodecamethylenediamine.

[0033] Examples of aromatic diamines include metaxylylenediamine.

[0034] Examples of the dicarboxylic acid include aliphatic dicarboxylic acids and aromatic dicarboxylic acids.

[0035] Examples of the aliphatic dicarboxylic acid include adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, and tetradecanedioic acid.

[0036] Examples of the aromatic dicarboxylic acid include terephthalic acid and isophthalic acid.

[0037] Examples of lactams include lactams having 6 to 12 carbon atoms, and specific examples include α-pyrrolidone, ε-caprolactam, ω-laurolactam, ε-enantholactam, and undecanelactam.

[0038] The aminocarboxylic acid includes aminocarboxylic acids having 6 to 12 carbon atoms, and specific examples thereof include 6-aminocaproic acid, 7-aminoheptanoic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid.

[0039] Polyamide compounds can be classified into, for example, aliphatic polyamide compounds and aromatic polyamide compounds, but in the present invention, aliphatic polyamide compounds are preferred from the viewpoint of low-temperature fixability.

[0040] Examples of the aliphatic polyamide compound include polycondensates of aliphatic diamines and aliphatic dicarboxylic acids, ring-opening polymers of lactams, and polycondensates of aliphatic aminocarboxylic acids.

[0041] Specific examples of aliphatic polyamide compounds include homopolymers such as polyamide 6, polyamide 11, polyamide 12, polyamide 66, polyamide 46, polyamide 610, polyamide 612, polyamide 912, polyamide 1010, and polyamide 1212, and copolymers such as polyamide 6 / 66, polyamide 6 / 12, and polyamide 11 / 12. At least one selected from the group consisting of polyamide 6 (nylon 6), polyamide 11 (nylon 11), and polyamide 12 (nylon 12) is preferred, nylon 11 and / or nylon 12 is more preferred, and nylon 12 is even more preferred.

[0042] The melting point of the polyamide compound is preferably 100°C or higher, more preferably 120°C or higher, and even more preferably 140°C or higher, from the viewpoint of heat-resistant storage stability, and is preferably 250°C or lower, more preferably 200°C or lower, and even more preferably 180°C or lower, from the viewpoint of low-temperature fixability and reactivity.

[0043] The content of the polyamide compound is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, and even more preferably 8 parts by mass or more, per 100 parts by mass of the total of the alcohol component and the carboxylic acid component, and is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, and even more preferably 15 parts by mass or less.

[0044] Crystalline polyester resin C can be produced, for example, by polycondensing an alcohol component, a carboxylic acid component, and a polyamide compound in an inert gas atmosphere, preferably in the presence of an esterification catalyst, and optionally in the presence of a cocatalyst, a polymerization inhibitor, etc., at a temperature of preferably 120°C or higher, more preferably 180°C or higher, and preferably 230°C or lower, more preferably 220°C or lower.

[0045] Examples of esterification catalysts include tin compounds such as dibutyltin oxide and tin(II) 2-ethylhexanoate, and titanium compounds such as titanium diisopropoxybis(triethanolaminate). The amount of the 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, more preferably 1 part by mass or less, per 100 parts by mass of the total of the alcohol component, the carboxylic acid component, and the polyamide compound. Examples of co-catalysts for the esterification catalyst include gallic acid. The amount of the 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, more preferably 0.1 parts by mass or less, per 100 parts by mass of the total of the alcohol component, the carboxylic acid component, and the polyamide compound. Examples of polymerization inhibitors include tert-butylcatechol. The amount of polymerization inhibitor used is preferably 0.001 part by mass or more, more preferably 0.01 part by mass or more, and preferably 0.5 part by mass or less, more preferably 0.1 part by mass or less, per 100 parts by mass of the total amount of the alcohol component, the carboxylic acid component, and the polyamide compound.

[0046] In the present invention, the polyester resin may be modified to such an extent that its properties are not substantially impaired. Examples of modified polyester resins include polyester resins grafted or blocked with phenol, urethane, epoxy, or the like, by the methods described in JP-A Nos. 11-133668, 10-239903, and 8-20636. Among the modified polyester resins, urethane-modified polyester resins in which polyester resins are urethane-extended with a polyisocyanate compound are preferred.

[0047] The melting point of the crystalline polyester resin C is 50°C or higher, preferably 60°C or higher, more preferably 65°C or higher, from the viewpoint of heat-resistant storage stability, and 140°C or lower, preferably 115°C or lower, more preferably 100°C or lower, from the viewpoint of low-temperature fixability.

[0048] The crystallinity of a resin is expressed by a crystallinity index defined as the ratio of the softening point to the maximum endothermic peak temperature measured by a differential scanning calorimeter, that is, the value of [softening point / maximum endothermic peak temperature]. The crystalline resin has 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, an amorphous resin is a resin in which no endothermic peak is observed, or if an endothermic peak is observed, the resin has a crystallinity index of more than 1.4, preferably more than 1.5, more preferably 1.6 or more, or less than 0.6, preferably 0.5 or less. The crystallinity of a resin can be adjusted by the types and ratios of raw material monomers, and production conditions (e.g., reaction temperature, reaction time, cooling rate), etc. The maximum endothermic peak temperature refers to the temperature of the peak with the largest peak area among the observed endothermic peaks. For crystalline resins, the maximum endothermic peak temperature is the melting point.

[0049] The softening point of the crystalline polyester resin C is preferably 50°C or higher, more preferably 60°C or higher, and even more preferably 65°C or higher from the viewpoint of durability, and is preferably 140°C or lower, more preferably 125°C or lower, and even more preferably 100°C or lower from the viewpoint of low-temperature fixability.

[0050] The acid value of the crystalline polyester resin C is preferably 1 mgKOH / g or more, more preferably 3 mgKOH / g or more, from the viewpoint of low-temperature fixability, and is preferably 30 mgKOH / g or less, more preferably 20 mgKOH / g or less, from the viewpoint of durability.

[0051] The content of crystalline polyester resin C is preferably 3% by mass or more, more preferably 5% by mass or more, and even more preferably 8% by mass or more, of the total amount of crystalline polyester resin C and amorphous resin A, from the viewpoint of low-temperature fixability, and is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 15% by mass or less, from the viewpoint of durability.

[0052] Examples of the amorphous resin A include amorphous polyester resins, vinyl resins such as styrene-acrylic resins, amorphous polyamide resins, amorphous epoxy resins, amorphous polycarbonate resins, amorphous polyurethane resins, and composite resins containing two or more of these resins. In the present invention, from the viewpoint of low-temperature fixability, amorphous polyester resins are preferred, amorphous polyester resins or amorphous composite resins containing a polyester resin and a styrene-based resin are more preferred, and amorphous polyester resins are even more preferred.

[0053] As the amorphous polyester resin, a polycondensation product of an alcohol component and a carboxylic acid component, including an alkylene oxide adduct of bisphenol A, is preferred.

[0054] Examples of alkylene oxide adducts of bisphenol A include those represented by the formula (I):

[0055] [ka]

[0056] (wherein OR and RO are oxyalkylene groups, R is an ethylene group and / or a propylene group, x and y are the average number of moles of alkylene oxide added and are each a positive number, and the sum of x and y is 1 or more, preferably 1.5 or more, and 16 or less, preferably 8 or less, more preferably 6 or less, and even more preferably 4 or less.) A compound represented by the following formula is preferred.

[0057] From the viewpoint of low-temperature fixability, the content of the alkylene oxide adduct of bisphenol A in the alcohol component is preferably 70 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, and even more preferably 95 mol% or more, and is 100 mol% or less.

[0058] Examples of other alcohol components include aliphatic diols, bisphenol A, hydrogenated bisphenol A, sorbitol, pentaerythritol, glycerin, tri- or higher hydric alcohols such as trimethylolpropane, and the like.

[0059] Examples of the carboxylic acid component include aromatic dicarboxylic acid compounds, aliphatic dicarboxylic acid compounds, and trivalent or higher carboxylic acid compounds.

[0060] Examples of aromatic dicarboxylic acid compounds include phthalic acid, isophthalic acid, terephthalic acid, anhydrides of these acids, and alkyl esters of these acids having 1 to 3 carbon atoms.

[0061] Examples of the aliphatic dicarboxylic acid compound include fumaric acid, maleic acid, succinic acid, succinic acid derivatives substituted with a hydrocarbon group, glutaric acid, adipic acid, sebacic acid, anhydrides of these acids, and alkyl esters of these acids having 1 to 3 carbon atoms.

[0062] Examples of the trivalent or higher carboxylic acid compound include trimellitic acid, pyromellitic acid, anhydrides of these acids, and alkyl esters of these acids having 1 to 3 carbon atoms.

[0063] The alcohol component may contain a monohydric alcohol, and the carboxylic acid component may contain a monocarboxylic acid compound, as appropriate.

[0064] From the viewpoint of adjusting the softening point of the polyester resin, the equivalent ratio of the carboxyl groups of the carboxylic acid component to the hydroxyl groups of the alcohol component (COOH groups / OH groups) is preferably 0.6 or more, more preferably 0.7 or more, even more preferably 0.8 or more, and is preferably 1.3 or less, more preferably 1.2 or less.

[0065] The polycondensation reaction conditions of the alcohol component and the carboxylic acid component of the amorphous polyester resin are the same as those of the crystalline polyester resin C, except that the suitable reaction temperature is preferably 130°C or higher, more preferably 170°C or higher, and preferably 250°C or lower, more preferably 240°C or lower.

[0066] In the amorphous composite resin, the polyester resin is the same as the amorphous polyester resin, and the styrene-based resin is an addition polymerization product of raw material monomers containing at least styrene or a styrene derivative such as α-methylstyrene or vinyltoluene (hereinafter, styrene and styrene derivatives are collectively referred to as "styrene compounds").

[0067] The content of the styrene compound, preferably styrene, in the raw material monomers of the styrene-based resin is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, from the viewpoint of storage stability, and is 100% by mass or less, and is preferably 95% by mass or less, more preferably 90% by mass or less, from the viewpoint of low-temperature fixability.

[0068] The styrene-based resin may also contain, as a raw material monomer, a (meth)acrylic acid alkyl ester having an alkyl group with 7 or more carbon atoms. Examples of (meth)acrylic acid alkyl esters include 2-ethylhexyl (meth)acrylate, (iso)octyl (meth)acrylate, (iso)decyl (meth)acrylate, and (iso)stearyl (meth)acrylate. It is preferable to use one or more of these. In this specification, "(iso)" means both the presence and absence of this group, and indicates normal when this group is not present. Furthermore, "(meth)acrylic acid" refers to acrylic acid, methacrylic acid, or both.

[0069] From the viewpoint of improving the low-temperature fixability of the toner, the number of carbon atoms in the alkyl group in the (meth)acrylic acid alkyl ester as a raw material monomer for the styrene-based resin is preferably 7 or more, more preferably 8 or more, and preferably 12 or less, more preferably 10 or less. The number of carbon atoms in the alkyl ester refers to the number of carbon atoms derived from the alcohol component constituting the ester.

[0070] The raw material monomers for styrene-based resins may include raw material monomers other than styrene compounds and (meth)acrylic acid alkyl esters, for example, ethylenically unsaturated monoolefins such as ethylene and propylene; diolefins such as butadiene; halovinyls such as vinyl chloride; vinyl esters such as vinyl acetate and vinyl propionate; ethylenic monocarboxylic acid esters such as dimethylaminoethyl (meth)acrylate; vinyl ethers such as methyl vinyl ether; vinylidene halides such as vinylidene chloride; and N-vinyl compounds such as N-vinylpyrrolidone.

[0071] The addition polymerization reaction of raw material monomers for styrene-based resins can be carried out by a conventional method in the presence of a polymerization initiator such as dibutyl peroxide or dicumyl peroxide, a chain transfer agent, a crosslinking agent, etc., in the presence of an organic solvent or without a solvent. The temperature conditions are preferably 110°C or higher, more preferably 140°C or higher, and preferably 200°C or lower, more preferably 170°C or lower.

[0072] When an organic solvent is used in the addition polymerization reaction, xylene, toluene, methyl ethyl ketone, acetone, etc. can be used. The amount of the organic solvent used is preferably 10 parts by mass or more and 50 parts by mass or less per 100 parts by mass of the raw material monomer of the styrene-based resin.

[0073] The amorphous composite resin is preferably a resin in which a polyester resin and a styrene-based resin are bonded together, and more preferably a resin in which a polyester resin and a styrene-based resin are chemically bonded together via a bireactive monomer that can react with both the raw material monomers of the polyester resin and the raw material monomers of the styrene-based resin.

[0074] The bireactive monomer is preferably a compound having at least one functional group selected from the group consisting of hydroxyl, carboxyl, epoxy, primary amino, and secondary amino groups, preferably a hydroxyl and / or carboxyl group, more preferably a carboxyl group, and an ethylenically unsaturated bond in the molecule, more preferably at least one selected from the group consisting of acrylic acid, methacrylic acid, fumaric acid, maleic acid, and maleic anhydride, and from the viewpoint of the reactivity of polycondensation reactions and addition polymerization reactions, even more preferably at least one selected from the group consisting of acrylic acid, methacrylic acid, and fumaric acid. However, when used together with a polymerization inhibitor, a polycarboxylic acid compound having an ethylenically unsaturated bond, such as fumaric acid, functions as a raw material monomer for polyester resin. In this case, fumaric acid, etc., is not a bireactive monomer but a raw material monomer for polyester resin.

[0075] The amount of the bireactive monomer used is preferably 1 mol or more, more preferably 2 mol or more, relative to 100 mol of the alcohol component of the polyester resin, from the viewpoint of increasing the dispersibility of the styrene resin and the polyester resin and improving the dispersibility of the raw materials in the toner, and is preferably 30 mol or less, more preferably 20 mol or less, and even more preferably 10 mol or less, from the viewpoint of improving the low-temperature fixability of the toner.

[0076] Specifically, the amorphous composite resin is preferably produced by the following method: When a bireactive monomer is used, the bireactive monomer is preferably used together with a raw material monomer of a styrene-based resin from the viewpoint of improving the dispersibility of the raw material in the toner and the low-temperature fixability.

[0077] (i) A method in which step (A) of polycondensation reaction using raw material monomers for polyester resin is followed by step (B) of addition polymerization reaction using raw material monomers for styrene-based resin. In this method, step (A) is carried out under reaction temperature conditions suitable for polycondensation reaction, and then the reaction temperature is lowered and step (B) is carried out under temperature conditions suitable for addition polymerization reaction. The raw material monomer for the styrene-based resin is preferably added to the reaction system at a temperature suitable for addition polymerization reaction. When a bireactive monomer is used together with the raw material monomer for the styrene-based resin, the bireactive monomer undergoes addition polymerization reaction and also reacts with the polyester resin. After step (B), the reaction temperature is raised again, and if necessary, a raw material monomer of a trivalent or higher polyester resin that serves as a crosslinking agent is added to the polymerization system, thereby further promoting the polycondensation reaction of step (A) and the reaction with the bireactive monomer.

[0078] (ii) A method in which step (B) of an addition polymerization reaction using raw material monomers for a styrene-based resin is followed by step (A) of a polycondensation reaction using raw material monomers for a polyester resin. In this method, step (B) is carried out under reaction temperature conditions suitable for an addition polymerization reaction, and then the reaction temperature is raised to carry out the polycondensation reaction in step (A) under temperature conditions suitable for a polycondensation reaction. When a bireactive monomer is used together with the raw material monomer for the styrene resin, the bireactive monomer participates in both the addition polymerization reaction and the polycondensation reaction. The raw material monomers for the polyester resin may be present in the reaction system during the addition polymerization reaction, or may be added to the reaction system under temperature conditions suitable for the polycondensation reaction. In the former case, the progress of the polycondensation reaction can be controlled by adding an esterification catalyst at a temperature suitable for the polycondensation reaction.

[0079] (iii) A method in which the step (A) of polycondensation reaction of raw material monomers for polyester resin and the step (B) of addition polymerization reaction of raw material monomers for styrene resin are carried out under conditions in which the reactions proceed in parallel. In this method, it is preferable to carry out steps (A) and (B) in parallel under reaction temperature conditions suitable for the addition polymerization reaction, raise the reaction temperature, and add a raw material monomer of the trivalent or higher polyester resin that serves as a crosslinking agent to the polymerization system as needed under temperature conditions suitable for the polycondensation reaction, and then further carry out the polycondensation reaction of step (A). In this case, under temperature conditions suitable for the polycondensation reaction, it is also possible to add a polymerization inhibitor and proceed with just the polycondensation reaction. When a bireactive monomer is used, the bireactive monomer participates in both the addition polymerization reaction and the polycondensation reaction.

[0080] In the above method (i), a prepolymerized polyester resin may be used instead of the polycondensation reaction in step (A). In the above method (iii), when the reaction is carried out under conditions in which steps (A) and (B) proceed in parallel, the reaction can also be carried out by dropping a mixture containing raw material monomers for the styrene resin into a mixture containing raw material monomers for the polyester resin.

[0081] The above methods (i) to (iii) are preferably carried out in the same container.

[0082] The mass ratio of the polyester resin to the styrene-based resin in the composite resin (polyester resin / styrene-based resin) is preferably 60 / 40 or more, more preferably 70 / 30 or more, and even more preferably 75 / 25 or more, from the viewpoint of low-temperature fixability. Also, from the viewpoint of improving the dispersibility of the raw materials in the toner, it is preferably 98 / 2 or less, more preferably 95 / 5 or less, and even more preferably 90 / 10 or less. In the above calculation, the mass of the polyester resin is the mass of the raw material monomers of the polyester resin used, minus the amount of reaction water (calculated value) dehydrated by the polycondensation reaction, and the amount of the bireactive monomer is included in the amount of raw material monomers of the polyester resin. The amount of the styrene-based resin is the total amount of the raw material monomers of the styrene-based resin and the polymerization initiator.

[0083] The softening point of the amorphous resin A is preferably 70°C or higher, more preferably 90°C or higher, and even more preferably 100°C or higher from the viewpoint of charging stability, and is preferably 170°C or lower, more preferably 160°C or lower, and even more preferably 150°C or lower from the viewpoint of low-temperature fixability.

[0084] From the viewpoint of low-temperature fixability and fixation width, the amorphous resin A may be composed of two or more resins with different softening points. The difference in softening points between the two resins is preferably 5°C or more, more preferably 10°C or more, and is preferably 40°C or less, more preferably 30°C or less.

[0085] The softening point of the amorphous resin with the higher softening point (resin AH) 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 is preferably 170°C or lower, more preferably 160°C or lower, and even more preferably 150°C or lower, from the viewpoint of low-temperature fixability.

[0086] Furthermore, the softening point of the amorphous resin having the lower softening point (resin AL) is preferably 70°C or higher, more preferably 90°C or higher, and even more preferably 100°C or higher, from the viewpoint of charging stability, and is 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 fixability.

[0087] From the viewpoint of durability, the weight average molecular weight of Resin AH is preferably 30,000 or more, more preferably 40,000 or more, and even more preferably 50,000 or more, and from the viewpoint of low-temperature fixability, it is preferably 300,000 or less, more preferably 250,000 or less, and even more preferably 200,000 or less.

[0088] The weight average molecular weight of the resin AL is preferably 5,000 or more, more preferably 6,000 or more, and even more preferably 7,000 or more, from the viewpoint of charging stability, and is preferably 100,000 or less, more preferably 75,000 or less, and even more preferably 50,000 or less, from the viewpoint of low-temperature fixability.

[0089] 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 is preferably 90 / 10 or less, more preferably 80 / 20 or less, even more preferably 70 / 30 or less.

[0090] The glass transition temperature of the amorphous resin A is preferably 45°C or higher, more preferably 50°C or higher, from the viewpoint of storage stability and durability, and is preferably 80°C or lower, more preferably 75°C or lower, from the viewpoint of low-temperature fixability.

[0091] The acid value of the amorphous resin A is preferably 1 mgKOH / g or more, more preferably 3 mgKOH / g or more, from the viewpoint of low-temperature fixability, and is preferably 20 mgKOH / g or less, more preferably 18 mgKOH / g or less, from the viewpoint of charging stability.

[0092] The number average molecular weight of the amorphous resin A is preferably 1,000 or more, more preferably 1,500 or more, from the viewpoint of durability, and is preferably 6,000 or less, more preferably 5,500 or less, and even more preferably 5,000 or less, from the viewpoint of low-temperature fixability.

[0093] The content of amorphous resin A in the total amount of crystalline polyester resin C and amorphous resin A is preferably 70% by mass or more, more preferably 75% by mass or more, and even more preferably 85% by mass or more, from the viewpoint of durability, and is preferably 97% by mass or less, more preferably 95% by mass or less, and even more preferably 92% by mass or less, from the viewpoint of low-temperature fixability.

[0094] From the viewpoint of achieving both low-temperature fixability and durability, the mass ratio of amorphous resin A to crystalline polyester resin C (amorphous resin A / crystalline polyester resin C) is preferably 70 / 30 or more, more preferably 75 / 25 or more, even more preferably 85 / 15 or more, and is preferably 97 / 3 or less, more preferably 95 / 5 or less, even more preferably 92 / 8 or less.

[0095] In the toner of the present invention, the crystalline polyester resin C and the amorphous resin A are contained as binder resins.

[0096] The total content of the amorphous resin A and the crystalline polyester resin C 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, and even more preferably 95% by mass or more, and is 100% by mass or less.

[0097] The content of the binder resin in the toner is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 75% by mass or more, and is preferably less than 100% by mass, more preferably 98% by mass or less, even more preferably 95% by mass or less.

[0098] The toner of the present invention may contain additives such as a colorant, a release agent, a charge control agent, a magnetic powder, a flowability improver, a conductivity adjuster, a reinforcing filler such as a fibrous substance, an antioxidant, and a cleaning property improver, in addition to the binder resin (binder).

[0099] As the colorant, dyes, pigments, magnetic materials, etc. used as toner colorants can be used. Examples include carbon black, phthalocyanine blue, permanent brown FG, brilliant fast scarlet, pigment red 122, pigment green B, rhodamine-B base, solvent red 49, solvent red 146, solvent blue 35, quinacridone, carmine 6B, isoindoline, disazo yellow, etc. In the present invention, the toner may be either a black toner or a color toner.

[0100] From the viewpoint of improving the image density and low-temperature fixability of the toner, the content of the colorant 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, relative to 100 parts by mass of the binder resin.

[0101] Examples of the release agent include hydrocarbon waxes such as polypropylene wax, polyethylene wax, ethylene-propylene copolymer wax, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax, and oxides thereof; ester waxes such as carnauba wax, montan wax, and deacidified waxes thereof, and fatty acid ester wax; fatty acid amides, fatty acids, higher alcohols, and fatty acid metal salts, and these may be used alone or in combination of two or more.

[0102] The melting point of the release agent is preferably 60°C or higher, more preferably 70°C or higher, from the viewpoint of toner transferability, and is 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 fixability.

[0103] The content of the 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, relative to 100 parts by mass of the binder resin, from the viewpoints of the low-temperature fixability and offset resistance of the toner and the dispersibility in the binder resin, and is 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.

[0104] The charge control agent is not particularly limited, and may contain either a positively chargeable charge control agent or a negatively chargeable charge control agent.

[0105] Positively chargeable 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 Co., Ltd.); triphenylmethane dyes containing a tertiary amine as a side chain; quaternary ammonium salt compounds such as "Bontron P-51" (manufactured by Orient Chemical Industries Co., Ltd.), cetyltrimethylammonium bromide, and "COPY CHARGE PX Examples of suitable resins include polyamine resins such as "AFP-B" (manufactured by Orient Chemical Industries Co., Ltd.); imidazole derivatives such as "PLZ-2001" and "PLZ-8001" (both manufactured by Shikoku Chemical Industry Co., Ltd.); and styrene-acrylic resins such as "FCA-701PT" and "FCA-201-PS" (manufactured by Fujikura Chemical Industries Co., Ltd.).

[0106] Examples of negatively chargeable charge control agents include metal-containing azo dyes such as "Balifast 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 benzilic acid compounds such as "LR-147" and "LR-297" (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 VP434 (manufactured by Clariant), nitroimidazole derivatives, etc.; organometallic compounds, etc.

[0107] From the viewpoint of the charging 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, relative to 100 parts by mass of the binder resin.

[0108] The toner of the present invention may be a toner obtained by any conventionally known method such as a melt-kneading method, an emulsion aggregation method, or a suspension polymerization method, and may also be a toner having a core-shell structure, but from the viewpoint of the mixability of the toner components, a pulverized toner obtained by a melt-kneading method is preferred. In the case of a pulverized toner obtained by a melt-kneading method, for example, raw materials such as crystalline polyester resin C, amorphous resin A, and, if necessary, a colorant, a release agent, and a charge control agent are uniformly mixed in a mixer such as a Henschel mixer, and then melt-kneaded in an internal kneader, a single-screw or twin-screw extruder, an open-roll kneader, or the like, followed by cooling, pulverization, and classification to produce the toner.

[0109] In order to improve the transferability of the toner of the present invention, it is preferable to use an external additive. Examples of the external additive include inorganic fine particles such as silica, alumina, titania, zirconia, tin oxide, and zinc oxide, and organic fine particles such as melamine-based resin fine particles and polytetrafluoroethylene resin fine particles, and two or more of these 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 subjected to a hydrophobic treatment is more preferred.

[0110] Examples of hydrophobic treatment agents for hydrophobizing the surfaces of silica particles include hexamethyldisilazane (HMDS), dimethyldichlorosilane (DMDS), cyclic silazanes, silicone oils, aminosilanes, octyltriethoxysilane (OTES), and methyltriethoxysilane.

[0111] From the viewpoint of the chargeability, fluidity, and transferability of the toner, the average particle diameter of the external additive is preferably 5 nm or more, more preferably 10 nm or more, and even more preferably 15 nm or more, and is preferably 250 nm or less, more preferably 200 nm or less, and even more preferably 90 nm or less.

[0112] The external addition treatment by mixing the toner particles with the external additives can be carried out in accordance with a conventional method, and a mixer such as a Henschel mixer can be used.

[0113] From the viewpoint of the chargeability, fluidity, and transferability of the toner, the content of the external additive is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, and even more preferably 0.3 parts by mass or more, relative to 100 parts by mass of the toner particles before treatment with the external additive, and is preferably 5 parts by mass or less, and more preferably 3 parts by mass or less.

[0114] The volume median particle size (D 50 ) is preferably 3 μm or more, more preferably 4 μm or more, and is preferably 15 μm or less, more preferably 10 μm or less. 50 ) means the particle size at which the cumulative volume frequency calculated by volume fraction is 50% starting from the smallest particle size. In addition, when 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.

[0115] The toner of the present invention can be used as a toner for one-component development as it is, or as a toner for two-component development mixed with a carrier, in an image forming apparatus of a one-component development system or a two-component development system, respectively. [Example]

[0116] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Physical properties of resins and the like can be measured by the following methods.

[0117] [Melting point of polyamide compound] Using a differential scanning calorimeter "Q-100" (manufactured by TA Instruments Japan Co., Ltd.), 0.02 g of sample is weighed into an aluminum pan, heated to 300°C, and then cooled from 300°C to 0°C at a rate of 10°C / min. The sample is then heated at a rate of 10°C / min, and the calorific value is measured to determine the endothermic peak. The maximum endothermic peak temperature is taken as the melting point.

[0118] [Softening point of resin] Using a flow tester "CFT-500D" (Shimadzu Corporation), 1 g of sample is heated at a temperature increase rate of 6°C / min while applying a load of 1.96 MPa with the plunger, and extruding it from a nozzle 1 mm in diameter and 1 mm in length. The plunger depression distance of the flow tester is plotted against the temperature, and the temperature at which half of the sample flows out is taken as the softening point.

[0119] [Maximum endothermic peak temperature of resin] Using a differential scanning calorimeter "Q-100" (TA Instruments Japan Co., Ltd.), 0.02 g of sample is weighed into an aluminum pan, cooled from room temperature (25°C) to 0°C at a rate of 10°C / min, and maintained at 0°C for 1 minute. Then, measurements are taken at a rate of 10°C / min. The temperature of the peak with the largest peak area among the observed endothermic peaks is taken as the maximum endothermic peak temperature. For crystalline resins, the maximum endothermic peak temperature is taken as the melting point.

[0120] [Glass transition temperature of resin] Using a differential scanning calorimeter "Q-100" (TA Instruments Japan), 0.02 g of sample is weighed into an aluminum pan, heated from room temperature (20 °C) to 200 °C at a heating rate of 10 °C / min, and cooled from that temperature to 0 °C at a heating rate of 10 °C / min. Next, the sample is heated at a heating rate of 10 °C / min, and the endothermic peak is measured. The glass transition temperature is 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 rising part of the peak to the peak apex.

[0121] [Acid value of resin] Measurements are made based on the method of JIS K 0070:1992, except that the measurement solvent is changed from the ethanol and ether mixture specified in JIS K 0070 to a mixture of acetone and toluene (acetone:toluene = 1:1 (volume ratio)) for amorphous resins, and to a mixture of chloroform and dimethylformamide (chloroform:dimethylformamide = 7:3 (volume ratio)) for crystalline resins.

[0122] [Weight average molecular weight (Mw) and number average molecular weight (Mn) of resin] The molecular weight distribution is measured by gel permeation chromatography (GPC) according to the following method, and the weight average molecular weight and number average molecular weight are determined. (1) Preparation of sample solution The sample is dissolved in tetrahydrofuran at 40°C to a concentration of 0.5 g / 100 mL. Next, this solution is filtered using a PTFE-type membrane filter "DISMIC-25JP" (manufactured by Toyo Roshi Kaisha, Ltd.) with a pore size of 0.20 μm to remove insoluble components, and the resulting solution is used as the sample solution. (2) Molecular weight measurement The following measurement equipment and analytical column are used, and tetrahydrofuran is used as the eluent at a flow rate of 1 mL per minute. The column is stabilized in a thermostatic bath at 40°C. 100 μL of sample solution is injected into the column and measurement is performed. The molecular weight of the sample is calculated based on a calibration curve prepared in advance. The calibration curve used here is a series of monodisperse polystyrenes (A-500 (5.0 × 10) manufactured by Tosoh Corporation) 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(1.09×106 )) was used as a standard sample. The molecular weight is indicated in parentheses. Measuring device: HLC-8220GPC (manufactured by Tosoh Corporation) Analytical column: TSKgel GMH XL +TSKgel G3000H XL (Manufactured by Tosoh Corporation)

[0123] [Melting point of release agent] Using a differential scanning calorimeter "Q-100" (TA Instruments Japan), 0.02 g of sample is weighed into an aluminum pan, heated to 200°C, and then cooled from 200°C to 0°C at a rate of 10°C / min. The sample is then heated at a rate of 10°C / min, and the calorific value is measured. The maximum endothermic peak temperature is taken as the melting point.

[0124] [Solid Content Concentration of Resin Particle Dispersion, Colorant Particle Dispersion, and Release Agent Particle Dispersion] Using an infrared moisture meter "FD-230" (Kett Electric Laboratory Co., Ltd.), 5 g of the measurement sample is dried at a drying temperature of 150°C and measurement mode 96 (monitoring time 2.5 minutes, fluctuation range 0.05%), and the moisture content (mass%) of the dispersion is measured. The solid content concentration is calculated according to the following formula. Solid concentration (mass%) = 100-moisture (mass%)

[0125] [Volume Median Particle Size and CV Value of Resin Particles, Colorant Particles, and Release Agent Particles] (1) Measuring device: Laser diffraction particle size measuring instrument "LA-920" (manufactured by Horiba, Ltd.) (2) Measurement conditions: Put the sample dispersion in a measurement cell, add distilled water, and measure the volume median particle size (D 50 ) and volume average particle diameter are measured. The CV value is calculated according to the following formula. CV value (%) = (standard deviation of particle size distribution / volume average particle size) x 100

[0126] [Volume Median Particle Diameter of Agglomerated Particles] Measuring instrument: "Coulter Multisizer (registered trademark) III" (manufactured by Beckman Coulter, Inc.) Aperture diameter: 50 μm Analysis software: "Multisizer (registered trademark) III Version 3.51" (Beckman Coulter, Inc.) Electrolyte: "Isoton (registered trademark) II" (manufactured by Beckman Coulter, Inc.) 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, 30,000 particles are measured, and the volume median particle size (D 50 ) is found.

[0127] [Circularity of toner particles (fused particles)] The circularity of the toner particles is measured under the following conditions. Measurement equipment: Flow particle image analyzer "FPIA-3000" (Sysmex Corporation) Preparation of dispersion: A dispersion of toner particles is prepared by diluting it with deionized water so that the solid content concentration is 0.001 to 0.05% by mass. Measurement mode: HPF measurement mode

[0128] [Average particle size of external additives] The average particle size refers to the number-average particle size, and is calculated by measuring the particle sizes (average values of major and minor axes) of 500 particles in a scanning electron microscope (SEM) photograph and averaging these values by number.

[0129] [Volume median particle size of toner (D 50 ) and CV value] Measuring instrument: "Coulter Multisizer (registered trademark) III" (manufactured by Beckman Coulter, Inc.) Aperture diameter: 50 μm Analysis software: "Multisizer III (registered trademark) Version 3.51" (Beckman Coulter, Inc.) Electrolyte: "Isoton (registered trademark) II" (manufactured by Beckman Coulter, Inc.) Dispersion: Polyoxyethylene lauryl ether "Emulgen (registered trademark) 109P" (manufactured by Kao Corporation, HLB (Griffin) = 13.6) dissolved in the electrolyte to adjust the concentration to 5% by mass Dispersion conditions: 10 mg of the measurement sample was added to 5 mL of the dispersion, and the mixture was dispersed for 1 minute using an ultrasonic disperser (machine name: US-1 manufactured by SND Corporation, output: 80 W). 25 mL of electrolyte was then added, and the mixture was further dispersed for 1 minute using the ultrasonic disperser to prepare a sample dispersion. Measurement conditions: The sample dispersion was added to 100 mL of the electrolyte to adjust the concentration so that the particle size of 30,000 particles could be measured in 20 seconds. Then, 30,000 particles were measured, and the volume median particle size (D 50 ) and volume average particle diameter. The CV value is calculated according to the following formula. CV value (%) = (standard deviation of particle size distribution / volume average particle size) x 100

[0130] Resin manufacturing example 1 The alcohol component, carboxylic acid component, polyamide compound, and esterification catalyst shown in Tables 1 and 2 were placed in a 5-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a downflow condenser, and a nitrogen inlet tube, and the temperature was raised to 220°C over 10 hours in a nitrogen atmosphere in a mantle heater. The reaction was then continued at 8 kPa until the softening points shown in Tables 1 and 2 were reached, yielding crystalline polyester resins (resins C1, C2, C4 to C6). The physical properties are shown in Tables 1 and 2.

[0131] Resin manufacturing example 2 The alcohol component, carboxylic acid component, polyamide compound, esterification catalyst, and polymerization inhibitor shown in Tables 1 and 2 were placed in a 5-liter four-neck flask equipped with a thermometer, stainless steel stirring rod, downflow condenser, and nitrogen inlet tube, and the temperature was raised to 210°C over 8 hours in a nitrogen atmosphere in a mantle heater. The reaction was then continued at 8 kPa until the softening points shown in Tables 1 and 2 were reached, yielding crystalline polyester resins (resins C3 and C8). The physical properties are shown in Tables 1 and 2.

[0132] Resin manufacturing example 3 The alcohol component, carboxylic acid component, polyamide compound, and esterification catalyst shown in Table 2 were placed in a 5-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a downflow condenser, and a nitrogen inlet tube, and the temperature was raised to 230°C over 12 hours in a nitrogen atmosphere in a mantle heater. The reaction was then continued at 8 kPa until the softening point shown in Table 2 was reached, yielding crystalline polyester resins (resins C7 and C10). The physical properties are shown in Table 2.

[0133] Resin manufacturing example 4 The alcohol and carboxylic acid components shown in Table 2 were placed in a 5-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a downflow condenser, and a nitrogen inlet tube, and the temperature was raised to 200°C over 8 hours in a nitrogen atmosphere in a mantle heater. Then, the esterification catalyst shown in Table 2 was added, and the reaction was carried out at 8 kPa until the softening point shown in Table 2 was reached, yielding a crystalline polyester resin (Resin C9). The physical properties are shown in Table 2.

[0134] [Table 1]

[0135] [Table 2]

[0136] Resin manufacturing example 5 The raw material monomers for the polyester resin other than trimellitic anhydride shown in Table 3, the esterification catalyst, and the cocatalyst were placed in a 5-liter four-neck flask equipped with a nitrogen inlet tube, a stirrer, and a thermocouple. The mixture was heated to 235°C under a nitrogen atmosphere and then polycondensed at 235°C for 6 hours. The temperature was then lowered to 210°C, and the trimellitic anhydride shown in Table 3 was added. The mixture was reacted at 210°C for 1 hour, and then further reacted at 210°C under a reduced pressure of 10 kPa until the softening point shown in Table 3 was reached, yielding an amorphous polyester resin (Resin AH1). The physical properties are shown in Table 3.

[0137] Resin manufacturing example 6 The raw material monomers for polyester resin other than trimellitic anhydride and fumaric acid shown in Table 3, the esterification catalyst, and the cocatalyst were placed in a 5-liter four-neck flask equipped with a dehydration tube with a nitrogen inlet, a stirrer, and a thermocouple. The mixture was heated to 235°C under a nitrogen atmosphere and then subjected to polycondensation at 235°C for 6 hours. The temperature was then lowered to 160°C, and a mixture of the bireactive monomers, raw material monomers for styrene resin, and a polymerization initiator shown in Table 3 was added dropwise over 1 hour using a dropping funnel. After the dropwise addition, the temperature was maintained at 160°C and the addition polymerization reaction was allowed to proceed for 1 hour. The temperature was then raised to 200°C and the pressure was reduced to 10 kPa for 1 hour. After the pressure was released, the temperature was lowered to 180°C, and the trimellitic anhydride, fumaric acid, and polymerization inhibitor shown in Table 3 were added. The mixture was then maintained at 180°C for 1 hour, after which the temperature was increased from 180°C to 210°C at a rate of 10°C / h and the reaction was carried out at 210°C for 1 hour. The reaction was further carried out at 210° C. under a reduced pressure of 10 kPa until the softening point shown in Table 3 was reached, to obtain an amorphous composite resin (Resin AH2).

[0138] Resin manufacturing example 7 The raw material monomers for the polyester resin other than trimellitic anhydride and fumaric acid shown in Table 3, the esterification catalyst, and the cocatalyst were placed in a 5-liter four-neck flask equipped with a nitrogen inlet tube, a stirrer, and a thermocouple. The mixture was heated to 235°C under a nitrogen atmosphere and then subjected to polycondensation at 235°C for 6 hours. The temperature was then lowered to 180°C, and trimellitic anhydride, fumaric acid, and the polymerization inhibitor shown in Table 3 were added. The mixture was then held at 180°C for 1 hour, after which the temperature was increased from 180°C to 210°C at a rate of 10°C / h and reacted at 210°C for 1 hour. The reaction was then continued at 210°C under a reduced pressure of 10 kPa until the softening point shown in Table 3 was reached, yielding an amorphous polyester resin (Resin AH3). The physical properties are shown in Table 3.

[0139] Resin manufacturing example 8 The raw material monomers, esterification catalyst, and cocatalyst for the polyester resins shown in Table 4 were placed in a 5-liter four-neck flask equipped with a nitrogen inlet tube, a stirrer, and a thermocouple, and the temperature was raised to 235°C under a nitrogen atmosphere, after which polycondensation was carried out at 235°C for 6 hours. The temperature was then lowered to 210°C, and the reaction was continued under a reduced pressure of 10 kPa until the softening point shown in Table 4 was reached, yielding amorphous polyester resins (resins AL1 and AL3). The physical properties are shown in Table 4.

[0140] Resin manufacturing example 9 The raw material monomers for the polyester resin other than fumaric acid shown in Table 4, the esterification catalyst, and the cocatalyst were placed in a 5-liter four-neck flask equipped with a dehydration tube with a nitrogen inlet, a stirrer, and a thermocouple. The flask was heated to 235°C under a nitrogen atmosphere and then subjected to polycondensation at 235°C for 6 hours. The temperature was then lowered to 160°C, and a mixture of the ambidextrous monomer, raw material monomers for the styrene resin, and a polymerization initiator shown in Table 4 was added dropwise over 1 hour using a dropping funnel. After the addition, the temperature was maintained at 160°C and the addition polymerization reaction was allowed to proceed for 1 hour. The temperature was then raised to 200°C and the pressure was reduced to 10 kPa for 1 hour. After the pressure was released, the temperature was lowered to 180°C, and the fumaric acid and polymerization inhibitor shown in Table 4 were added. The flask was then maintained at 180°C for 1 hour, after which the temperature was increased from 180°C to 210°C at a rate of 10°C / h and the reaction was carried out at 210°C for 1 hour. Furthermore, the reaction was continued at 210° C. under a reduced pressure of 10 kPa until the softening point shown in Table 4 was reached, thereby obtaining an amorphous composite resin (resin AL2).

[0141] [Table 3]

[0142] [Table 4]

[0143] Examples 1 to 12 and Comparative Examples 1 and 2 [Melt-kneading method] 100 parts by mass of the binder resin shown in Table 5, 5 parts by mass of a colorant "ECB-301" (manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd., phthalocyanine blue (PB15:3)), 3 parts by mass of a release agent "Carnauba Wax C1" (manufactured by Kato Yoko Co., Ltd., melting point: 83°C), and 0.5 parts by mass of a negatively chargeable charge control agent "Bontron E-304" (manufactured by Orient Chemical Industries Co., Ltd.) were mixed in a Henschel mixer.

[0144] The resulting mixture was melt-kneaded using a co-rotating twin-screw extruder with a kneading section total length of 1560 mm, a screw diameter of 42 mm, and a barrel inner diameter of 43 mm at a screw rotation speed of 200 r / min and a barrel temperature setting of 100°C to obtain a kneaded product. The mixture was fed at a rate of 20 kg / h and had an average residence time of approximately 18 seconds.

[0145] The resulting melt-kneaded product was cooled and coarsely crushed, then crushed in a jet mill, and classified using an air classifier (manufactured by Nippon Pneumatic Mfg. Co., Ltd.) to obtain the volume median particle diameter (D 50 ) toner particles of 7.0 μm were obtained.

[0146] 100 parts by mass of the obtained toner particles and 1.0 part by mass of hydrophobic silica "R972" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic treatment agent: DMDS, average particle size: 16 nm) and 1.0 part by mass of hydrophobic silica "RY-50" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic treatment agent: silicone oil, average particle size: 40 nm) as external additives were mixed in a Henschel mixer (manufactured by Nippon Coke and Engineering Co., Ltd.) at a rotation speed of 3000 r / min (circumferential speed: 32 m / sec) for 3 minutes to obtain a toner.

[0147] Example 13 A toner was obtained in the same manner as in Example 1, except that a continuous twin-roll open-roll kneader "Kneedex" (manufactured by Nippon Coke and Engineering Co., Ltd.) was used for melt-kneading instead of a co-rotating twin-screw extruder. The continuous twin-roll open-roll kneader had an outer diameter of 0.14 m and an effective roll length of 0.8 m. The operating conditions were a rotation speed of the high-speed roll (front roll) of 75 r / min (circumferential speed of 33 m / min), a rotation speed of the low-speed roll (rear roll) of 50 r / min (circumferential speed of 22 m / min), and a roll gap of 0.1 mm. The heating and cooling medium temperatures within the rolls were set as follows: the temperature on the raw material inlet side of the high-speed roll was 140°C, and the temperature on the kneaded material outlet side was 110°C; and the temperature on the raw material inlet side of the low-speed roll was 65°C, and the temperature on the kneaded material outlet side was 30°C. The raw material mixture was supplied at a rate of 10 kg / h, and the average residence time was approximately 5 minutes.

[0148] Example 14 [Emulsion aggregation method] <Preparation of Resin Dispersion> (1) 200 g of Resin AH1 and 200 g of methyl ethyl ketone were placed in a 3-liter vessel equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen inlet tube, and dissolved at 73° C. for 2 hours. A 5% by mass aqueous solution of sodium hydroxide was added to the resulting solution so that the degree of neutralization relative to the acid value of the resin was 60 mol %, and the mixture was stirred for 30 minutes. Next, while maintaining the temperature at 73°C, 700 g of deionized water was added over 50 minutes while stirring at 200 r / min, causing phase inversion emulsification. While maintaining the temperature at 73°C, the methyl ethyl ketone was distilled off under reduced pressure to obtain a dispersion. Thereafter, while continuing to stir, the dispersion was cooled to 30°C, and deionized water was added so that the solids concentration became 20 mass% to obtain a resin dispersion (resin dispersion X1). The volume median particle diameter (D 50 ) was 150 nm and the CV value was 25%.

[0149] (2) A resin dispersion (resin dispersion X2) was obtained in the same manner as in resin dispersion X1, except that 200 g of resin AL1 was used instead of resin AH1. The volume median particle diameter (D 50) was 140 nm and the CV value was 24%.

[0150] (3) A resin dispersion (resin dispersion X3) was obtained in the same manner as in resin dispersion X1, except that 200 g of resin C1 was used instead of resin AH1. The volume median particle diameter (D 50 ) was 260 nm and the CV value was 28%.

[0151] <Preparation of Colorant Dispersion> In a 1-liter beaker, 116.2 g of colorant "ECB-301" (Dainichiseika Color & Chemicals Mfg. Co., Ltd., Phthalocyanine Blue (PB15:3)), 154.9 g of anionic surfactant "Neopelex (registered trademark) G-15" (Kao Corporation, 15% by mass aqueous solution of sodium dodecylbenzenesulfonate), and 260 g of deionized water were mixed and dispersed using a homogenizer at room temperature for 3 hours, and then deionized water was added to obtain a colorant dispersion so that the solids concentration became 20% by mass. The volume median particle diameter (D 50 ) was 118 nm and the CV value was 27%.

[0152] <Preparation of release agent dispersion> 50 g of a release agent (manufactured by Nippon Seiro Co., Ltd., trade name: FNP0090, Fischer-Tropsch wax, melting point: 90°C), 5 g of a cationic surfactant (manufactured by Kao Corporation, trade name: Sanisol B50), and 200 g of deionized water were heated to 95°C, and the release agent was dispersed using a homogenizer. The mixture was then dispersed using a pressure discharge homogenizer, and deionized water was added to obtain a release agent dispersion with a solids concentration of 20 mass%. The volume median particle diameter (D 50 ) was measured at 550 nm, and the CV value was 26%.

[0153] <Agglomeration process> 225 g of Resin Dispersion X1, 225 g of Resin Dispersion X2, 50 g of Resin Dispersion X3, 54 g of Colorant Dispersion, 35 g of Release Agent Dispersion, and 3.3 g of 15% by mass sodium dodecylbenzenesulfonate aqueous solution "Neopelex G-15" (Kao Corporation, anionic surfactant) were placed in a 3-liter four-neck flask equipped with a dehydration tube, a stirrer, and a thermocouple, and mixed at a temperature of 25°C. Next, while stirring the resulting mixture, a solution prepared by dissolving 43 g of ammonium sulfate in 980 g of deionized water and adding 4.8% by mass potassium hydroxide aqueous solution to adjust the pH to 8.2 was added dropwise over 10 minutes at 25°C, and the temperature was then raised to 58°C over 2 hours to measure the volume median particle diameter (D 50 The temperature was maintained at 58°C until the particle diameter reached 7.0 µm, thereby obtaining a dispersion of aggregated particles.

[0154] <Fusing process> To the obtained dispersion of aggregated particles, 22 g of sodium polyoxyethylene lauryl ether sulfate "EMAL E-27C" (manufactured by Kao Corporation, anionic surfactant, effective concentration 27% by mass) and 1,100 g of deionized water were added. The temperature was then raised to 75°C over 1 hour and maintained at 75°C until the circularity reached 0.970, thereby obtaining a dispersion of fused particles in which the aggregated particles were fused together.

[0155] The resulting dispersion of fused particles was cooled to 30°C, and the dispersion was subjected to suction filtration to separate the solid content. The solid content was then washed with deionized water at 25°C and suction filtration was carried out at 25°C for 2 hours. Thereafter, the solid content was vacuum dried at 33°C for 24 hours using a vacuum constant temperature dryer "DRV622DA" (manufactured by ADVANTEC Corporation) to determine the volume median particle diameter (D 50 ) toner particles of 7.0 μm were obtained.

[0156] <External addition process> 100 parts by mass of the obtained toner particles and 1.0 part by mass of hydrophobic silica "R972" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic treatment agent: DMDS, average particle size: 16 nm) and 1.0 part by mass of hydrophobic silica "RY-50" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic treatment agent: silicone oil, average particle size: 40 nm) as external additives were mixed in a Henschel mixer (manufactured by Nippon Coke and Engineering Co., Ltd.) at a rotation speed of 3000 r / min (circumferential speed: 32 m / sec) for 3 minutes to obtain a toner.

[0157] Test Example 1 [Heat-resistant storage stability] 10 g of toner was placed in a 50 mL polyethylene container and kept in an environment of 50°C and 60% RH for 24 hours. After that, three sieves, namely, sieve A (mesh size 250 μm), sieve B (mesh size 150 μm), and sieve C (mesh size 75 μm), were placed in a powder tester (manufactured by Hosokawa Micron Corporation) in stacked order from top to bottom, and 10 g of toner was placed on sieve A and vibrated for 60 seconds. The toner mass A (g) remaining on sieve A, the toner mass B (g) remaining on sieve B, and the toner mass C (g) remaining on sieve C were each measured, and the heat-resistant storage stability was evaluated based on the value (α) calculated using the following formula. The results are shown in Table 5. The larger the value, the higher the fluidity after storage and the better the heat-resistant storage stability. α=100-(A+B×0.6+C×0.2) / 10×100

[0158] Test Example 2 [Low temperature fixability] (1) Before storage The toner was loaded into a copy machine "AR-505" (manufactured by Sharp Corporation) whose fixing unit was modified to enable fixing outside the machine, and a printout was obtained in an unfixed state (print area: 2 cm × 12 cm, adhesion amount: 0.5 mg / cm 2). Then, using a fixing machine (fixing speed: 300 mm / sec) adjusted to a total fixing pressure of 40 kgf, the temperature of the fixing roll was raised in 5°C increments from 100°C to 200°C, and a fixing test was conducted on the unfixed print at each temperature. Cellophane adhesive tape "UNICEF Cellophane" (Mitsubishi Pencil Co., Ltd., width: 18 mm, JIS Z1522:2009) was applied to the image portion of the resulting print. The print was then passed through a fixing roller set at 30°C, separate from the fixing roll of the fixing machine, and the tape was then peeled off. The optical reflection density of the image before and after tape application was measured using a reflection densitometer "RD-915" (Gretag Macbeth). The fixing roll temperature at which the ratio (after peeling / before application x 100) first exceeded 90% was defined as the minimum fixing temperature. The results are shown in Table 5. A lower minimum fixing temperature indicates better low-temperature fixability. The fixing paper used was "CopyBond SF-70NA" (manufactured by Sharp Corporation, 75 g / m 2 ) was used.

[0159] (2) After saving 100 g of toner was placed in a 200 mL polyethylene container and left to stand for 24 hours in a high-temperature, high-humidity environment of 50°C and 60% RH. The minimum fixing temperature was then measured in the same manner as in (1) above, and the low-temperature fixing ability was evaluated. The results are shown in Table 5.

[0160] [Table 5]

[0161] From the above results, it is clear that Examples 1 to 14 are excellent in heat-resistant storage stability and low-temperature fixability after storage. In contrast, the toner of Comparative Example 1, which contains a crystalline polyester resin that does not use a polyamide compound, has excellent low-temperature fixability before storage, but is insufficient in low-temperature fixability and heat-resistant storage stability after storage.Furthermore, the toner of Comparative Example 2, which contains a crystalline polyester resin with an excessively high melting point, is insufficient in low-temperature fixability both before and after storage. [Industrial Applicability]

[0162] The toner for developing electrostatic images 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 crystalline polyester resin C and an amorphous resin A, wherein the crystalline polyester resin C is a polycondensate of an alcohol component, a carboxylic acid component, and a polyamide compound, and the melting point of the crystalline polyester resin C is 50°C or higher and 140°C or lower.

2. 2. The toner for developing electrostatic images according to claim 1, wherein the content of the crystalline polyester resin C is 3% by mass or more and 30% by mass or less of the total amount of the crystalline polyester resin C and the amorphous resin A.

3. 3. The toner for developing electrostatic images according to claim 1, wherein the carboxylic acid component of the crystalline polyester C contains an aliphatic dicarboxylic acid compound.

4. 3. The toner for developing electrostatic images according to claim 1, wherein the content of the polyamide compound is 3 parts by mass or more and 30 parts by mass or less per 100 parts by mass of the total of the alcohol component and the carboxylic acid component of the crystalline polyester resin C.

5. 3. The toner for developing electrostatic images according to claim 1, wherein the melting point of the polyamide compound is 100°C or higher and 200°C or lower.

Images