Toner for developing electrostatic images

Abstract

To provide toner for electrostatic charge image development which achieves both low temperature fixability and heat-resistant storage property.SOLUTION: Toner for electrostatic charge image development contains a binder resin containing an amorphous resin and a crystalline resin, wherein the amorphous resin contains an amorphous polyester resin A which is a polycondensation product of an alcohol component that contains 50 mol% or more and 99 mol% or less of aliphatic diol and 1 mol% or more and 50 mol% or less of diol having a fluorene skeleton and has a content of diol having a bisphenol A skeleton of less than 10 mol% and a carboxylic acid component, and the crystalline resin contains a crystalline polyester resin C which is a polycondensation product of an alcohol component containing aliphatic diol and a carboxylic acid component containing an aliphatic dicarboxylic acid-based compound.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. [Background technology]

[0002] While alkylene oxide adducts of bisphenol A have been commonly used as the alcohol component of polyester resins, there have also been reports of the use of bisphenol A having a fluorene skeleton (see Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2007-310257 [Overview of the project] [Problems that the invention aims to solve]

[0004] Crystalline polyester resins are known to be effective in improving the low-temperature fixation of toner as a binder resin, and their use in combination with amorphous resins is being considered. However, conventionally, in order to ensure the heat resistance of toner during storage, it is necessary to improve the degree of recrystallization of the crystalline resin in the amorphous resin, and one way to do this is to reduce the compatibility between the resins. On the other hand, in order to improve low-temperature fixation, it is necessary to improve the compatibility between the resins, so there is a trade-off relationship between heat resistance and low-temperature fixation.

[0005] This invention relates to a toner for electrostatic image development that achieves both low-temperature fixation and heat-resistant storage. [Means for solving the problem]

[0006] The present invention relates to an electrostatic charge image developing toner containing a binder resin containing an amorphous resin and a crystalline resin, wherein the amorphous resin contains 50 mol% or more and 99 mol% or less of an aliphatic diol and 1 mol% or more and 50 mol% or less of a diol having a fluorene skeleton, and has a content of a diol having a bisphenol A skeleton of less than 10 mol%. The toner contains an amorphous polyester resin A which is a polycondensate of an alcohol component and a carboxylic acid component, and the crystalline resin contains a crystalline polyester resin C which is a polycondensate of an alcohol component containing an aliphatic diol and a carboxylic acid component containing an aliphatic dicarboxylic acid compound.

Effects of the Invention

[0007] The electrostatic charge image developing toner of the present invention exhibits excellent effects in achieving both low-temperature fixing property and heat-resistant storage property.

Embodiments for Carrying Out the Invention

[0008] The electrostatic charge image developing toner of the present invention contains a binder resin containing an amorphous resin and a crystalline resin. The amorphous resin contains a predetermined amount of an aliphatic diol and a diol having a fluorene skeleton as an alcohol component, while having a large feature in that the content of the diol having a bisphenol A skeleton is limited. Although the details of the reason for the effects of the present invention are not clear, it is推测 as follows.

[0009] The fluorene skeleton contained in the amorphous polyester resin A is more planar than the benzene ring, so it is easy to stack and becomes a crystal nucleus by π-π interaction. Thus, while maintaining the compatibility with the crystalline resin, it can promote the recrystallization of the crystalline resin. That is, by using a monomer having a fluorene skeleton for the amorphous resin, it is possible to achieve both low-temperature fixing property and heat-resistant storage property. However, if amorphous polyester resin contains a large amount of easily rotating benzene rings, it inhibits stacking of fluorene skeletons. In contrast, in the present invention, by using an aliphatic diol as the main alcohol component of amorphous polyester resin A and limiting the amount of diol having a bisphenol A skeleton, the effect of diol having a fluorene skeleton can be significantly enhanced.

[0010] Amorphous polyester resin A is a polycondensate of an alcohol component and a carboxylic acid component, containing predetermined amounts of aliphatic diols and diols having a fluorene skeleton, with a limited content of diols having a bisphenol A skeleton, as described above.

[0011] The crystallinity of a resin is expressed by a crystallinity index, which is defined by the ratio of the softening point to the maximum endothermic peak temperature measured by a differential scanning calorimeter, i.e., the value of [softening point / maximum endothermic peak temperature]. The crystalline resin is a resin having a crystallinity index of 0.6 or higher, preferably 0.7 or higher, more preferably 0.9 or higher, and 1.4 or lower, preferably 1.2 or lower, more preferably 1.1 or lower. On the other hand, amorphous resins are those in which no endothermic peak is observed, or, if observed, those with a crystallinity index greater than 1.4, preferably greater than 1.5, more preferably 1.6 or higher, or less than 0.6, preferably 0.5 or lower. The crystallinity of a resin can be adjusted by the type and ratio of raw material monomers, as well as the manufacturing conditions (e.g., reaction temperature, reaction time, cooling rate). The maximum endothermic peak temperature refers to the temperature of the peak with the largest peak area among the observed endothermic peaks. In crystalline resins, the maximum endothermic peak temperature is defined as the melting point.

[0012] Examples of aliphatic diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,2-pentanediol, 1,3-pentanediol, 2,3-pentanediol, 2,4-pentanediol, 1,6-hexanediol, 1,4-butenediol, 1,3-butanediol, neopentyl glycol, and others.

[0013] From the viewpoint of low-temperature fixability, the carbon number of the aliphatic diol is preferably 2 or more, more preferably 3 or more, and from the viewpoint of heat-resistant storage, it is preferably 6 or less, more preferably 5 or less.

[0014] From the viewpoint of heat-resistant storage, aliphatic diols are preferred that have a hydroxyl group bonded to a secondary carbon atom, such as 1,2-propanediol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 1,2-pentanediol, 1,3-pentanediol, 2,3-pentanediol, and 2,4-pentanediol, with 1,2-propanediol being more preferred.

[0015] The aliphatic diol content is 50 mol% or more of the alcohol component, preferably 60 mol% or more, more preferably 70 mol% or more, and 99 mol% or less, preferably 90 mol% or less, and more preferably 85 mol% or less.

[0016] In diols having a fluorene skeleton, the fluorene skeleton is defined by formula (I):

[0017] [ka]

[0018] (In the formula, R 1 and R 2 (where is a monovalent substituent, and m and n are between 0 and 4.) This refers to a structure represented by [this symbol].

[0019] In formula (I), R 1 and R 2 are each independently a monovalent substituent. Examples of the monovalent substituent include a halogen atom, an alkyl group, an alkoxy group, a cycloalkyl group, an aryl group, an aralkyl group, a -NO2 group, etc. Among these, an alkyl group, an aryl group or an aralkyl group is preferable, and an alkyl group is more preferable.

[0020] Examples of the alkyl group include linear or branched alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, t-butyl group, etc. The number of carbon atoms of the alkyl group is preferably 1 or more, and preferably 7 or less, more preferably 6 or less, and still more preferably 4 or less. As the alkyl group, an alkyl group having 1 to 4 carbon atoms is preferable, and a methyl group is more preferable.

[0021] Examples of the aryl group include aryl groups having 6 to 12 carbon atoms such as phenyl group, naphthyl group, etc.

[0022] Examples of the aralkyl group include benzyl group, etc. An aralkyl group composed of an aryl group having 6 to 12 carbon atoms and an alkyl group having 1 to 4 carbon atoms is preferable.

[0023] m R 1 and n R 2 can each be independently selected. The substitution positions of R 1 and R 2 are not particularly limited, but m and n are preferably 3 or less, more preferably 2 or less, and it is even more preferable that they are 0, that is, R 1 and R 2 are not present.

[0024] From the viewpoint of reactivity with the carboxylic acid component, as the diol having a fluorene skeleton, a compound having an alkylene oxide chain in addition to the fluorene skeleton is preferable. For example, formula (II):

[0025] [ka]

[0026] (In the formula, R 3 and R 4 is an alkylene group, R 5 ~R 8 R is a hydrogen atom or a monovalent substituent, p and q represent the average number of moles added, each being a positive number, and the sum of p and q is between 1 and 8. 1 , R 2 (m and n are the same as above) Compounds represented by are preferred.

[0027] In equation (II), R 3 and R 4 Each of these is an alkylene group independently. Preferably, the alkylene group is a linear or branched group with 1 to 4 carbon atoms, more preferably a methylene group, an ethylene group, a propylene group, or a butylene group, even more preferably an ethylene group or a propylene group, and even more preferably an ethylene group.

[0028] p and q are alkylene oxide groups (-OR 3 -), (-OR 4 This represents the average number of moles added. The sum of p and q is 1 or more, preferably 1.5 or more, and 8 or less, preferably 4 or less. p and q are preferably between 1 and 4, more preferably 2 or less, and even more preferably 1. Also, p and q can be selected independently, but it is preferable that p and q are the same, and more preferably that p and q are 1. That is, it is preferable that the compound represented by formula (II) has two ethylene oxide chains.

[0029] -O-(R 3 O) pH, -O-(R 4 The substitution position of O)qH is not particularly limited, but substitution at position 4 is preferred.

[0030] R 5 ~R8 Each of these is independently a hydrogen atom or a monovalent substituent. Examples of monovalent substituents include halogen atoms, alkyl groups, alkoxy groups, cycloalkyl groups, aryl groups, aralkyl groups, -NO2 groups, etc., and these groups may further have substituents such as alkyl groups, cycloalkyl groups, aryl groups, halogen atoms, etc. 5 ~R 8 As such, hydrogen atoms, alkyl groups, aryl groups, or aralkyl groups are preferred, hydrogen atoms or alkyl groups are more preferred, and hydrogen atoms are even more preferred. For alkyl groups, aryl groups, and aralkyl groups, R 1 and R 2 This is the same as what was written about.

[0031] R 5 ~R 8 The substitution positions are not particularly limited, but positions 2, 3, 4, 2 and 6, and positions 3 and 5 are preferred.

[0032] Specific examples of compounds represented by formula (II) include 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3-methylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3,5-dimethylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3-ethylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3,5-diethylphenyl]fluorene, and 9,9-bis[4-(2-hydroxyethoxy)-3,5-diethylphenyl]fluorene. [Droxyethoxy)-3-propylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3,5-dipropylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3-isopropylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3,5-diisopropylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3-n-butylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3,5-di-n-butylphenyl]fluorene Fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3-isobutylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3,5-diisobutylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3-(1-methylpropyl)phenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3,5-bis(1-methylpropyl)phenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3-phenylphenyl]fluorene Examples include orene, 9,9-bis[4-(2-hydroxyethoxy)-3,5-diphenylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3-benzylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3,5-dibenzylphenyl]fluorene, 9,9-bis[4-(3-hydroxypropoxy)phenyl]fluorene, and 9,9-bis[4-(4-hydroxybutoxy)phenyl]fluorene, which may be used individually or in combination of two or more. Among these, 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene (hereinafter also referred to as bisphenoxyethanol fluorene (BPEF)) is preferred.

[0033] 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene is obtained, for example, by adding ethylene oxide (hereinafter abbreviated as EO) to 9,9-bis(4-hydroxyphenyl)fluorene. In this case, in addition to the 2EO adduct (9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene), in which one molecule of ethylene oxide is added to each of the hydroxyl groups of phenol, impurities such as 3EO adducts and 4EO adducts may be present, which are formed by adding several molecules in excess. That is, the added ethylene oxide has a distribution, and the 2EO adduct is defined as one in which the maximum value of that distribution is 2EO adduct. In order to improve the heat resistance of the polyester resin, the purity of the 2EO adduct is preferably 85% or higher, and more preferably 95% or higher.

[0034] The content of diols having a fluorene skeleton is 1 mol% or more, preferably 5 mol% or more, more preferably 10 mol% or more, and 50 mol% or less, preferably 40 mol% or less, and more preferably 30 mol% or less, in the alcohol component.

[0035] In a diol having a bisphenol A skeleton, the bisphenol A skeleton is defined by formula (III):

[0036] [ka]

[0037] This refers to a structure represented by [this symbol].

[0038] Diols having a bisphenol A skeleton include those of formula (IV):

[0039] [ka]

[0040] (In the formula, OR 9 and R 10O is an oxyalkylene group, R 9 and R 10 (where x is an ethylene group 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.) Examples include alkylene oxide adducts of bisphenol A, such as ethylene oxide adducts of bisphenol A and propylene oxide adducts of bisphenol A, and bisphenol A itself.

[0041] The content of diols having a bisphenol A skeleton is less than 10 mol% of the alcohol component, preferably 8 mol% or less, more preferably 5 mol% or less, and even more preferably 3 mol% or less, and even more preferably 0 mol%, i.e., the alcohol component does not contain diols having a bisphenol A skeleton.

[0042] Furthermore, the diol having the fluorene skeleton does not have a bisphenol A skeleton, and the diol having the bisphenol A skeleton is a diol that does not have a fluorene skeleton.

[0043] From the viewpoint of heat resistance and storage properties, aromatic dicarboxylic acid compounds are preferred as the carboxylic acid component.

[0044] Examples of aromatic dicarboxylic acid compounds include phthalic acid, isophthalic acid, terephthalic acid, anhydrides of these acids, and alkyl esters with one to three carbon atoms in the alkyl group. Among these, terephthalic acid or isophthalic acid is preferred from the viewpoint of low-temperature fixability, and terephthalic acid is more preferred.

[0045] The content of aromatic dicarboxylic acid compounds in the carboxylic acid component 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 even more preferably 100 mol% from the viewpoint of low-temperature fixability.

[0046] Other carboxylic acid components include fumaric acid, maleic acid, succinic acid, succinic acid derivatives substituted with hydrocarbon groups, aliphatic dicarboxylic acids such as glutaric acid, adipic acid, and sebacic acid, trivalent or higher carboxylic acids such as trimellitic acid and pyromellitic acid, anhydrides of these acids, and alkyl esters of these acids with 1 to 3 carbon atoms.

[0047] The alcohol component may contain a monohydric alcohol, and the carboxylic acid component may contain a monohydric carboxylic acid compound, as appropriate.

[0048] In this specification, macromonomers and hydroxycarboxylic acids are not included in the alcohol and carboxylic acid components.

[0049] 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 0.3 or higher, more preferably 0.4 or higher, even more preferably 0.45 or higher, and preferably 0.9 or lower, more preferably 0.7 or lower, and even more preferably 0.6 or lower, from the viewpoint of adjusting the softening point of the polyester resin.

[0050] Amorphous polyester resin A can be produced, for example, by polycondensing an alcohol component and a carboxylic acid component 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.

[0051] Examples of esterification catalysts include tin compounds such as dibutyltin oxide and tin(II) 2-ethylhexanoate, and titanium compounds such as titanium diisopropylate bistriethanolamine. 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 the total amount of alcohol and carboxylic acid components. 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 the total amount of alcohol and carboxylic acid components. 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, based on 100 parts by mass of the total amount of alcohol and carboxylic acid components.

[0052] In this invention, the polyester resin may be a polyester resin that has been modified to such an extent that its properties are not substantially impaired. Examples of modified polyester resins include 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. Among modified polyester resins, urethane-modified polyester resins obtained by urethane elongation of polyester resin with a polyisocyanate compound are preferred.

[0053] The softening point of amorphous polyester resin A is preferably 90°C or higher, more preferably 100°C or higher, from the viewpoint of heat-resistant storage, and preferably 150°C or lower, more preferably 140°C or lower, from the viewpoint of low-temperature fixing properties.

[0054] The glass transition temperature of amorphous polyester resin A is preferably 40°C or higher, more preferably 50°C or higher, and even more preferably 60°C or higher, from the viewpoint of heat-resistant storage, and preferably 80°C or lower, more preferably 70°C or lower, from the viewpoint of low-temperature fixing properties.

[0055] From the viewpoint of electrostatic stability, the acid value of amorphous polyester resin A is preferably 1 mg KOH / g or more, more preferably 3 mg KOH / g or more, and preferably 20 mg KOH / g or less, more preferably 15 mg KOH / g or less.

[0056] The hydroxyl value of amorphous polyester resin A is preferably 100 mg KOH / g or more, more preferably 200 mg KOH / g or more, and preferably 270 mg KOH / g or less, more preferably 230 mg KOH / g or less, from the viewpoint of electrostatic stability.

[0057] The weight-average molecular weight of amorphous polyester resin A is preferably 2000 or more, more preferably 2500 or more, and even more preferably 3000 or more, from the viewpoint of heat-resistant storage properties, and preferably 8000 or less, more preferably 7000 or less, even more preferably 5000 or less, and even more preferably 4000 or less, from the viewpoint of low-temperature fixation properties.

[0058] The content of amorphous polyester resin A is preferably 50% by mass or more, more preferably 60% by mass or more, and from the viewpoint of hot offset resistance, preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 75% by mass or less.

[0059] Preferably, the amorphous resin further contains amorphous polyester resin B, which has a higher softening point than amorphous polyester resin A.

[0060] As the amorphous polyester resin B, a polycondensate of an alcohol component containing an aliphatic diol and a carboxylic acid component containing an aromatic dicarboxylic acid compound is preferred.

[0061] Examples of aliphatic diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,2-pentanediol, 1,3-pentanediol, 2,3-pentanediol, 2,4-pentanediol, 1,6-hexanediol, 1,4-butenediol, 1,3-butanediol, neopentyl glycol, and others.

[0062] The number of carbon atoms in the aliphatic diol is preferably 2 or more from the viewpoint of low-temperature fixability, and preferably 8 or less, more preferably 6 or less, from the viewpoint of heat-resistant storage.

[0063] In the alcohol component of amorphous polyester resin B, the content of the diol having the fluorene skeleton is less than 1 mol%, preferably 0 mol%.

[0064] Examples of aromatic dicarboxylic acid compounds include phthalic acid, isophthalic acid, terephthalic acid, anhydrides of these acids, and alkyl esters with one to three carbon atoms in the alkyl group. Among these, terephthalic acid or isophthalic acid is preferred from the viewpoint of low-temperature fixability, and terephthalic acid is more preferred.

[0065] The content of aromatic dicarboxylic acid compounds is preferably 40 mol% or more, more preferably 50 mol% or more, even more preferably 60 mol% or more, and preferably 90 mol% or less, more preferably 80 mol% or less, and even more preferably 75 mol% or less, in the carboxylic acid component.

[0066] From the viewpoint of adjusting the softening point, it is preferable that the carboxylic acid component further contains a carboxylic acid compound with a valency of 3 or higher.

[0067] 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.

[0068] The content of trivalent or higher carboxylic acid compounds is preferably 5 mol% or more, more preferably 15 mol% or more, and even more preferably 20 mol% or more of the carboxylic acid component, and from the viewpoint of low-temperature fixability, it is preferably 50 mol% or less, more preferably 40 mol% or less, and even more preferably 35 mol% or less.

[0069] Other carboxylic acid components include fumaric acid, maleic acid, succinic acid, succinic acid derivatives substituted with hydrocarbon groups, aliphatic dicarboxylic acids such as glutaric acid, adipic acid, and sebacic acid, anhydrides of these acids, and alkyl esters of these acids with 1 to 3 carbon atoms.

[0070] The alcohol component may appropriately contain a monohydric alcohol, and the carboxylic acid component may appropriately contain a monohydric carboxylic acid compound.

[0071] 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.

[0072] The polycondensation reaction conditions between the alcohol component and the carboxylic acid component are the same as those for amorphous polyester resin A.

[0073] The softening point of amorphous polyester resin B is preferably 120°C or higher, more preferably 130°C or higher, from the viewpoint of hot offset resistance, and preferably 165°C or lower, more preferably 150°C or lower, from the viewpoint of low-temperature fixing properties.

[0074] The difference in softening points between amorphous polyester resin A and amorphous polyester resin B is preferably 15°C or higher, more preferably 20°C or higher, even more preferably 25°C or higher, and preferably 55°C or lower, more preferably 45°C or lower, and even more preferably 35°C or lower.

[0075] The glass transition temperature of amorphous polyester resin B is preferably 40°C or higher, more preferably 50°C or higher, from the viewpoint of heat-resistant storage, 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 fixing properties.

[0076] From the viewpoint of electrostatic stability, the acid value of amorphous polyester resin B is preferably 5 mg KOH / g or more, more preferably 10 mg KOH / g or more, and preferably 50 mg KOH / g or less, more preferably 45 mg KOH / g or less.

[0077] The hydroxyl value of amorphous polyester resin B is preferably 40 mg KOH / g or more, more preferably 50 mg KOH / g or more, and preferably 65 mg KOH / g or less, more preferably 60 mg KOH / g or less, from the viewpoint of electrostatic stability.

[0078] The weight-average molecular weight of amorphous polyester resin B is preferably 50,000 or more, more preferably 100,000 or more, and even more preferably 120,000 or more, from the viewpoint of hot offset resistance, and preferably 200,000 or less, more preferably 175,000 or less, and even more preferably 160,000 or less, from the viewpoint of low-temperature fixation.

[0079] The content of amorphous polyester resin B is preferably 10% by mass or more, more preferably 20% by mass or more, and from the viewpoint of low-temperature fixability, preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 35% by mass or less.

[0080] The mass ratio of amorphous polyester resin A to amorphous polyester resin B (amorphous polyester resin A / amorphous polyester resin B) is preferably 50 / 50 or more, more preferably 60 / 40 or more, and even more preferably 65 / 35 or more, from the viewpoint of low-temperature fixing properties, and preferably 90 / 10 or less, more preferably 80 / 20 or less, and even more preferably 75 / 25 or less, from the viewpoint of hot offset resistance.

[0081] The total content of amorphous polyester resin A and amorphous polyester resin B is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 100% by mass of the amorphous resin.

[0082] Other amorphous resins include amorphous polyester resins other than amorphous polyester resin A and amorphous polyester resin B, vinyl resins such as styrene-acrylic resin, epoxy resins, polycarbonate, polyurethane, and composite resins containing two or more of these resins.

[0083] The amorphous resin content in the binder resin is preferably 70% by mass or more, more preferably 80% by mass or more, from the viewpoint of heat-resistant storage, and preferably 98% 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 fixing properties.

[0084] Crystalline polyester resin C is a polycondensate of an alcohol component containing an aliphatic diol and a carboxylic acid component containing an aliphatic dicarboxylic acid compound.

[0085] Examples of aliphatic diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, neopentyl glycol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, and 1,12-dodecanediol. One or more of these may be used in combination. Among these, 1,10-decanediol is preferred.

[0086] From the viewpoint of low-temperature fixation, the aliphatic diol is preferably an α,ω-aliphatic diol having a hydroxyl group at the end of the carbon chain, and more preferably an α,ω-linear alkanediol.

[0087] The number of carbon atoms in the aliphatic diol is preferably 2 or more, more preferably 6 or more, from the viewpoint of dispersibility of the colorant, and preferably 14 or less, more preferably 12 or less, and even more preferably 10 or less, from the viewpoint of storage stability.

[0088] The aliphatic diol content 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 even more preferably 100 mol% of the alcohol component.

[0089] Other alcohol components include aromatic diols such as alkylene oxide adducts of bisphenol A, sorbitol, pentaerythritol, glycerin, trivalent or higher alcohols such as trimethylolpropane, and others.

[0090] Examples of aliphatic dicarboxylic acid compounds include succinic acid (4 carbon atoms), fumaric acid (4 carbon atoms), adipic acid (6 carbon atoms), suberic acid (8 carbon atoms), azelaic acid (9 carbon atoms), sebacic acid (10 carbon atoms), dodecanediic acid (12 carbon atoms), tetradecanediic acid (14 carbon atoms), succinic acid having an alkyl or alkenyl group in its side chain, anhydrides of these acids, and alkyl esters of these acids with 1 to 3 carbon atoms.

[0091] From the viewpoint of low-temperature fixability, the carbon number of the aliphatic dicarboxylic acid compound is preferably 4 or more, more preferably 6 or more, and from the viewpoint of storage stability, it is preferably 14 or less, more preferably 12 or less, and even more preferably 10 or less.

[0092] The content of the aliphatic dicarboxylic acid compound 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 even more preferably 100 mol% of the carboxylic acid component.

[0093] Other carboxylic acid components include aromatic dicarboxylic acid compounds, aliphatic dicarboxylic acid compounds, and trivalent or higher carboxylic acid compounds.

[0094] The equivalent ratio of the carboxyl group of the carboxylic acid component to the hydroxyl group of the alcohol component (COOH group / OH group) is preferably 0.8 or higher, more preferably 0.9 or higher, from the viewpoint of preservation, and preferably 1.2 or lower, more preferably 1.1 or lower, from the viewpoint of low-temperature fixation.

[0095] The polycondensation reaction conditions between the alcohol component and the carboxylic acid component are the same as those for amorphous polyester resin A, except that the preferred reaction temperature is between 120°C and 230°C.

[0096] The softening point of the crystalline polyester resin C is preferably 60°C or higher, more preferably 70°C or higher, from the viewpoint of durability, and preferably 110°C or lower, more preferably 100°C or lower, from the viewpoint of low-temperature fixability.

[0097] The melting point of the crystalline polyester resin C is preferably 50°C or higher, more preferably 60°C or higher, from the viewpoint of durability, and preferably 110°C or lower, more preferably 100°C or lower, from the viewpoint of low-temperature fixability.

[0098] The acid value of the crystalline polyester resin C is preferably 3 mg KOH / g or more, more preferably 5 mg KOH / g or more, from the viewpoint of durability, and preferably 35 mg KOH / g or less, more preferably 30 mg KOH / g or less, from the viewpoint of low-temperature fixability.

[0099] The content of crystalline polyester resin C in the crystalline resin is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 100% by mass, from the viewpoint of low-temperature fixability.

[0100] The crystalline resin content in the binder resin is preferably 2% by mass or more, more preferably 5% by mass or more, from the viewpoint of low-temperature fixation, and preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less, from the viewpoint of heat-resistant storage.

[0101] Other crystalline resins include crystalline polyester resins other than crystalline polyester resin C, polyethylene, polypropylene, and crystalline vinyl resins such as crystalline styrene-acrylic resin.

[0102] The mass ratio of amorphous resin to crystalline resin (amorphous resin / crystalline resin) is preferably 70 / 30 or more, more preferably 80 / 20 or more, and even more preferably 85 / 15 or more, from the viewpoint of heat-resistant storage, and preferably 98 / 2 or less, more preferably 95 / 5 or less, and even more preferably 92 / 8 or less, from the viewpoint of low-temperature fixation.

[0103] Furthermore, the mass ratio of amorphous polyester resin A to crystalline polyester resin C (amorphous polyester resin A / crystalline polyester resin C) is preferably 60 / 40 or more, more preferably 70 / 30 or more, and even more preferably 80 / 20 or more, from the viewpoint of heat-resistant storage, and preferably 98 / 2 or less, more preferably 95 / 5 or less, and even more preferably 90 / 10 or less, from the viewpoint of low-temperature fixation.

[0104] The binder resin content in the toner is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, and preferably 99% by mass or less, more preferably 98% by mass or less, and even more preferably 95% by mass or less.

[0105] The electrostatic image developing toner of the present invention may contain additives other than the binder resin, such as colorants, release agents, charge control agents, magnetic powders, flowability enhancers, conductivity modifiers, reinforcing fillers such as fibrous materials, antioxidants, and cleaning properties enhancers.

[0106] As colorants, dyes, pigments, magnetic materials, etc., used as colorants for toners can be used. Examples include carbon black, phthalocyanine blue, permanent brown FG, brilliant first scarlet, pigment red 122, pigment green B, rhodamine-B base, solvent red 49, solvent red 146, solvent blue 35, quinacridone, carmine 6B, isoindoline, disazoel, etc. In this invention, the toner may be either black toner or color toner.

[0107] From the viewpoint of improving the image density of the toner and its low-temperature fixability, the amount of 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 10 parts by mass or less, per 100 parts by mass of the binder resin.

[0108] 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.

[0109] 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 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.

[0110] The release agent content is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, 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, per 100 parts by mass of binder resin, from the viewpoint of low-temperature fixation and offset resistance of the toner and dispersibility in the binder resin.

[0111] 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.

[0112] 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.).

[0113] 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.

[0114] 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, per 100 parts by mass of the binder resin.

[0115] 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, but from the viewpoint of productivity and dispersibility of the colorant, pulverized toner obtained by the melt-kneading method is preferred. In the case of pulverized toner obtained by the melt-kneading method, for example, it is obtained by a method that includes a step of melt-kneading a mixture containing a binder resin and, if necessary, additives such as a colorant, release agent, and charge control agent (melt-kneading step).

[0116] 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.

[0117] 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.

[0118] The melting and mixing temperature is not particularly limited as long as it is the temperature at which the resin melts and mixes together.

[0119] 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.

[0120] 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.

[0121] Examples of hydrophobic agents used to hydrophobize the surface of silica particles include hexamethyldisilazane (HMDS), dimethyldichlorosilane (DMDS), cyclic silazane, silicone oil, aminosilane, octyltriethoxysilane (OTES), and methyltriethoxysilane.

[0122] 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.

[0123] A mixer such as a Henschel mixer can be used to mix the toner particles with the external additive.

[0124] 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.

[0125] The volume-intermediate particle size (D) of the toner of the present invention 50 The 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.

[0126] The toner of the present invention can be used as is as a one-component developing toner, or as a two-component developing toner used in combination with a carrier, in image forming apparatuses using either a one-component developing method or a two-component developing method, respectively. [Examples]

[0127] 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.

[0128] [Softening point of resin] 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.

[0129] [Maximum peak temperature of endothermic resin] 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 at a heating rate of 10°C / min, and then cooled to 0°C at a cooling rate of 10°C / min. Next, the sample is heated to 180°C at a heating rate of 10°C / min and measured. From the endothermic peaks observed in the resulting melting endothermic curve, the temperature of the peak with the largest peak area is defined as the maximum endothermic peak temperature.

[0130] [Glass transition temperature of resins] Using a differential scanning calorimeter "Q-20" (manufactured by T.A. Instruments Japan), 0.01 to 0.02 g of the sample is weighed into an aluminum pan and heated from room temperature (20°C) to 200°C at a heating rate of 10°C / min, and then cooled to 0°C at a cooling rate of 10°C / min. Next, the sample is heated to 180°C at a heating rate of 10°C / min and the endothermic peak is measured. 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 is defined as the glass transition temperature.

[0131] [Acid value of resins] Measurements will be performed according to the method of JIS K 0070:1992. However, the measurement solvent will be changed from the ethanol and ether mixed solvent specified in JIS K 0070 to a mixed solvent of acetone and toluene (acetone:toluene = 1:1 (volume ratio)) for amorphous resins, and to a mixed solvent of chloroform and dimethylformamide (chloroform:dimethylformamide = 7:3 (volume ratio)) for crystalline resins.

[0132] [Hydroxyl value of resins] The measurement will be performed according to the method of JIS K 0070:1992. However, the measurement solvent will be changed from the mixed solvent of ethanol and ether specified in JIS K 0070 to tetrahydrofuran.

[0133] [Weight-average molecular weight of resins] The molecular weight distribution was measured by gel permeation chromatography (GPC), obtained using the following method, and the weight-average molecular weight was determined. (1) Preparation of sample solution The sample was dissolved in tetrahydrofuran (for amorphous polyester resin) or chloroform (for crystalline polyester resin) at 25°C to a concentration of 0.5 g / 100 mL. This solution was then filtered using a fluoropolymer filter "DISMIC-25JP" (manufactured by ADVANTEC) with a pore size of 0.2 μm (for amorphous polyester resin) or a fluoropolymer filter "FP-200" (manufactured by Sumitomo Electric Industries, Ltd.) with a pore size of 2 μm (for crystalline polyester resin) to remove undissolved material and obtain the sample solution. (2) Molecular weight measurement Using the measurement apparatus and analytical column described below, tetrahydrofuran (for amorphous polyester resins) or chloroform (for crystalline polyester resins) is flowed as the eluent at a flow rate of 1 mL / min, and the column is stabilized in a constant temperature bath at 40°C. 100 μL of the sample solution is then injected, and the measurement is performed. The molecular weight of the sample is calculated based on a calibration curve prepared in advance. The calibration curve at this time includes several types of monodisperse polystyrene "A-500" (5.0 × 10⁻¹⁰). 2 ), "A-1000" (1.01 x 10 3 ), "A-2500" (2.63 x 10 3 ), "A-5000" (5.97 x 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 The following samples were prepared using the following product (manufactured by Tosoh Corporation) as a standard sample. The values ​​in parentheses indicate the molecular weight. Measuring device: "HLC-8220CPC" (manufactured by Tosoh Corporation) (for amorphous polyester resins) or "CO-8010" (manufactured by Tosoh Corporation) (for crystalline polyester resins) Analysis column: "GMH XL "+"G3000H XL(Manufactured by Tosoh Corporation)

[0134] [Melting point of release agent] 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 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 release agent.

[0135] [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.

[0136] [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 )

[0137] Resin manufacturing example 1 The alcohol component, carboxylic acid component, and esterification catalyst shown in Table 1 were placed in a 10-liter four-necked flask equipped with a thermometer, stainless steel stirring rod, fractionation column, dehydration tube, condenser, and nitrogen inlet tube. The flask was then heated in a mantle heater under a nitrogen atmosphere at 180°C for 1 hour, after which the temperature was increased from 180°C to 230°C at a rate of 10°C / h. After confirming that the reaction rate reached 95% at 230°C, the reaction was carried out at 8 kPa until the desired softening point was reached, yielding amorphous polyester resins (resins A1 to A5). In this specification, the reaction rate refers to the value of (mol) of water produced / (mol) of theoretical water produced × 100.

[0138] Resin manufacturing example 2 The alcohol component, carboxylic acid component, and esterification catalyst shown in Table 1 were placed in a 10-liter four-necked flask equipped with a thermometer, stainless steel stirring rod, fractionation column, dehydration tube, 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 95% at 235°C, the reaction was carried out at 8 kPa until the desired softening point was reached, yielding an amorphous polyester resin (resin A6).

[0139] Resin manufacturing example 3 The alcohol components, carboxylic acid components other than trimellitic anhydride, and esterification catalyst shown in Table 1 were placed in a 10-liter four-necked flask equipped with a thermometer, stainless steel stirring rod, fractionation column, dehydration tube, condenser, and nitrogen inlet tube. The mixture was kept warm at 180°C for 1 hour in a mantle heater under a nitrogen atmosphere, and then the temperature was increased from 180°C to 230°C at a rate of 10°C / h. After confirming that the reaction rate reached 95% at 235°C, the mixture was cooled to 180°C, and trimellitic anhydride shown in Table 1 was added. The mixture was then heated to 220°C over 2 hours. After reacting at 220°C for 1 hour, the reaction was continued at 8 kPa until the desired softening point was reached, yielding an amorphous polyester resin (resin B1).

[0140] [Table 1]

[0141] Resin manufacturing example 4 The alcohol and carboxylic acid components shown in Table 2 were placed in a 10-liter four-necked flask equipped with a thermometer, stainless steel stirring rod, distillation column, dehydration tube, condenser, and nitrogen inlet tube. The flask was then heated in a mantle heater under a nitrogen atmosphere at 130°C for 1 hour, after which the temperature was increased from 130°C to 200°C at a rate of 10°C / h. The mixture was then reacted at 200°C for 2 hours, after which an esterification catalyst was added, and the reaction was carried out at 8 kPa until the desired softening point was reached, yielding crystalline polyester resins (resins C1-C3).

[0142] [Table 2]

[0143] Examples 1-6 and Comparative Examples 1-3 100 parts by mass of the binder resin shown in Table 3, 1 part by mass of the negative charge control agent "Bontron E-81" (manufactured by Orient Chemical Industry Co., Ltd.), 5 parts by mass of the coloring agent "Pigment blue 15:3" (manufactured by Dainichi Seika Kogyo Co., Ltd., phthalocyanine blue), and 2 parts by mass of the release agent "HNP-9" (manufactured by Nippon Seiro Co., Ltd., paraffin wax, melting point: 75°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 roll rotation speed of 200 r / min and a heating temperature of 100°C inside the rolls. 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 volume particle size (D 50 ) yielded toner particles with a diameter of 8 μm.

[0144] Toner was obtained by adding 1.0 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) as an external additive to 100 parts by mass of the obtained toner particles and mixing them in a Henschel mixer.

[0145] Test Example 1 [Low Temperature Fixation] A modified fuser unit of the "AR-505" copier (manufactured by Sharp Corporation) was modified to allow for fixing outside the unit. Each toner was mounted on this modified unit, and a printout was obtained in an unfixed state (print area: 2cm x 12cm, adhesion amount: 0.5mg / cm²). 2 Subsequently, using a fuser (fixing speed 300 mm / sec) adjusted to a total fixing pressure of 40 kgf, fixing tests were performed on unfixed printed materials at each temperature while sequentially increasing the temperature of the fixing roll from 80°C to 240°C in 5°C increments. Cellophane adhesive tape "UNICEF Cellophane" (manufactured by Mitsubishi Pencil Co., Ltd., width: 18 mm, JIS Z1522) was attached to the image portion of the obtained printed material, and after passing it through a fixing roller set to 30°C, the tape was peeled off. The optical reflectance density before and after tape application was measured using a reflectance densitometer "RD-915" (manufactured by Gretag Macbeth Co., Ltd.), and the temperature of the fixing roll at which the ratio of the two (after peeling / before application × 100) first exceeded 90% was defined as the minimum fixing temperature, and the low-temperature fixing performance was evaluated. The lower the minimum fixing temperature, the better the low-temperature fixing performance. The results are shown in Table 3.

[0146] Test Example 2 [Heat Resistance and Storage Properties] Each toner (5g) was placed in a 50mL polyethylene container and left for 48 hours at a temperature of 50°C and a relative humidity of 60%. The toner was then sieved through a 100μm mesh, and the remaining toner on the mesh was weighed. The heat resistance was then evaluated according to the following criteria. The results are shown in Table 3. [Evaluation Criteria] A: Remaining toner is less than 0.5g B: Remaining toner is between 0.5g and less than 1g C: Remaining toner is between 1g and 1.5g D: Remaining toner is 1.5g or more

[0147] [Table 3]

[0148] From the results above, it can be seen that Examples 1 to 6 achieve both low-temperature fixation and heat-resistant storage. Furthermore, a comparison of Comparative Examples 1-3 with Example 1 shows that using crystalline polyester resin improves low-temperature fixability, and that combining a diol having a fluorene skeleton with an aliphatic diol, rather than a diol having a bisphenol A skeleton, improves heat-resistant storage. [Industrial applicability]

[0149] 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, comprising an amorphous resin and a binder resin containing a crystalline resin, wherein the amorphous resin contains amorphous polyester resin A, which is a polycondensate of an alcohol component and a carboxylic acid component, and the amorphous resin contains 50 mol% to 99 mol% of aliphatic diol and 1 mol% to 50 mol% of a diol having a fluorene skeleton, and the content of a diol having a bisphenol A skeleton is less than 10 mol%, and the crystalline resin contains crystalline polyester resin C, which is a polycondensate of an alcohol component containing an aliphatic diol and a carboxylic acid component containing an aliphatic dicarboxylic acid compound.

2. The electrostatic image developing toner according to claim 1, wherein the weight-average molecular weight of amorphous polyester resin A is 7,000 or less.

3. The electrostatic image developing toner according to claim 1 or 2, wherein the content of a diol having a fluorene skeleton is 5 mol% or more and 40 mol% or less in the alcohol component of amorphous polyester resin A.

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