Toner for developing electrostatic charge images

Abstract

To provide a toner for developing electrostatic charge images that exhibits superior low-temperature fixability and superior durability under high temperature and high humidity conditions, and a method for producing the same.SOLUTION: A toner for developing electrostatic charge images and a method for producing the same are provided, the toner comprising toner base particles that contain a crystalline polyester resin C and an amorphous polyester resin A, and an external additive, wherein the crystalline polyester resin C is a polycondensate of an alcohol component containing 60 mol% or more of ethylene glycol and a carboxylic acid component containing an aliphatic dicarboxylic acid compound, the number-based median particle diameter (D50) of the toner base particles, determined from the number particle size distribution, is 5.0 μm or more and 10.0 μm or less, and the proportion of particles in the range from 0 μm to (D50-2.0) μm is 9.5 number% or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an electrostatic charge image developing toner used for developing a latent image formed in an electrophotographic method, an electrostatic recording method, an electrostatic printing method, etc., and a method for manufacturing the same.

Background Art

[0002] In the field of electrophotography, with the development of electrophotographic systems, there is a demand for the development of an electrostatic charge image developing toner (hereinafter, also simply referred to as "toner") that can cope with high image quality and high speed. For example, due to the high speed of the machine, the amount of heat applied to the toner coated on the recording paper during fixing decreases, so the toner is required to have excellent low-temperature fixability.

[0003] Therefore, as a binder resin for the toner, it is known that a crystalline polyester resin is effective in improving the low-temperature fixability of the toner, and its combined use with an amorphous polyester resin has been studied (see Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when a crystalline polyester resin is used in combination with an amorphous polyester resin, there is a problem that the durability under high temperature and high humidity tends to decrease.

[0006] The present invention relates to an electrostatic charge image developing toner excellent in low-temperature fixability and durability under high temperature and high humidity, and a method for manufacturing the same.

Means for Solving the Problems

[0007] The present invention relates to [1] A toner for developing electrostatic images, comprising toner base particles containing a crystalline polyester resin C and an amorphous polyester resin A, and an external additive, wherein the crystalline polyester resin C is a polycondensate of an alcohol component containing 60 mol % or more of ethylene glycol and a carboxylic acid component containing an aliphatic dicarboxylic acid compound, and the number median particle diameter (D 50 ) is 5.0μm or more and 10.0μm or less, and 0μm to (D 50 -2.0) μm or less particles are 9.5% by number or less for electrostatic image development toner; [2] A method for producing the toner for developing electrostatic images according to the above [1], comprising the steps of melt-kneading a mixture containing a crystalline polyester resin C and an amorphous polyester resin A, pulverizing and classifying the resulting kneaded product to obtain toner base particles, and mixing the resulting toner base particles with an external additive. Regarding. Effect of the Invention

[0008] The toner for developing electrostatic images of the present invention exhibits excellent effects in terms of low-temperature fixing property and durability under high-temperature and high-humidity conditions. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The toner for developing electrostatic images of the present invention contains toner base particles containing crystalline polyester resin C obtained using ethylene glycol and amorphous polyester resin A, and an external additive, and the toner base particles have a specific particle size distribution. The reason why the toner for developing electrostatic images of the present invention has excellent low-temperature fixing property and durability under high-temperature and high-humidity conditions is not clear, but is presumed to be as follows. Note that the following mechanism is presumed and is not limited thereto.

[0010] Since a highly hydrophobic crystalline polyester resin has poor dispersibility in the toner component, it easily forms relatively large domains in the kneaded material of the raw materials during toner production, and is prone to cracking at the domain interfaces during pulverization, making it easy to be exposed on the surface of the toner particles. At the exposed portions of the crystalline polyester resin on the toner surface, the glass transition temperature becomes low. Therefore, especially under high temperature and high humidity, the toner easily adheres to the printer member, and the durability deteriorates. Furthermore, since the domains of the crystalline polyester resin form fine powder components, the crystalline polyester resin with poor dispersibility tends to be unevenly distributed on the side of the small particle size components of the toner mother particles. On the other hand, in the present invention, by using ethylene glycol as the main component of the alcohol component constituting the crystalline polyester resin C, a large number of ester groups adjacent to each other can be arranged in the main chain of the crystalline polyester resin C, and the affinity with a more polar amorphous polyester resin is improved, so that the crystalline polyester resin C can be finely dispersed in the toner particles. As a result, the exposure on the surface of the toner particles and the uneven distribution on the small particle size components are suppressed. Moreover, in the present invention, the small particle size components of the toner particles are reduced. Although the small particle size components are considered to easily adhere to the toner member, if the small particle size components are reduced in a state where the crystalline polyester resin is unevenly distributed in the small particle size components, the amount of the crystalline polyester resin contained in the whole toner decreases and the low temperature fixability deteriorates. However, in the present invention, since the uneven distribution of the crystalline polyester resin C in the small particle size components is suppressed, there is no uneven distribution of the component distribution, and it is considered that the low temperature fixability is maintained and the durability under high temperature and high humidity can be improved.

[0011] The number median particle size (D 50 ) is 5 μm or more, preferably 5.5 μm or more, more preferably 6.0 μm or more, and 10 μm or less, preferably 8.5 μm or less, more preferably 7.0 μm or less, from the viewpoints of low temperature fixability and durability under high temperature and high humidity. In the present specification, the number median particle size (D 50 ) means the particle size at which the cumulative number frequency calculated by the number fraction becomes 50% when calculated from the smaller particle size.

[0012] Also, in the number-based particle size distribution of the toner mother particles, the proportion of particles from 0 μm to (D 50 - 2.0) μm is 9.5% by number or less, preferably 7.0% by number or less, more preferably 6.0% by number or less, and still more preferably 5.5% by number or less.

[0013] The coefficient of variation (CV value) based on the volume-based particle size distribution of the toner mother particles is preferably 14.0% or more, more preferably 15.0% or more, still more preferably 15.5% or more from the viewpoint of improving toner productivity, and is preferably 18.0% or less, more preferably 17.5% or less, still more preferably 16.5% or less from the viewpoint of developability.

[0014] The particle size distribution of the toner mother particles can be appropriately adjusted according to the grinding conditions and classification conditions.

[0015] The crystalline polyester resin C is a polycondensate of an alcohol component containing ethylene glycol as a main component and a carboxylic acid component containing an aliphatic dicarboxylic acid compound.

[0016] The content of ethylene glycol is 60 mol% or more, preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, still more preferably 95 mol% or more in the alcohol component, and is 100 mol% or less. When the alcohol component contains a monoalcohol, it is preferably 98 mol% or less, more preferably 95 mol% or less.

[0017] Examples of other alcohol components include aliphatic diols other than ethylene glycol such as 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, 1,12-dodecanediol; alkylene oxide adducts of bisphenol A; aromatic diols such as bisphenol A; hydrogenated bisphenol A; polyhydric alcohols having three or more hydroxyl groups such as sorbitol, pentaerythritol, glycerin, trimethylolpropane, etc.

[0018] Examples of aliphatic dicarboxylic acid compounds include succinic acid (carbon number: 4), fumaric acid (carbon number: 4), adipic acid (carbon number: 6), suberic acid (carbon number: 8), azelaic acid (carbon number: 9), sebacic acid (carbon number: 10), dodecanedioic acid (carbon number: 12), tetradecanedioic acid (carbon number: 14), succinic acid having an alkyl group or alkenyl group in the side chain, anhydrides of these acids, and alkyl esters of these acids having 1 to 3 carbon atoms in the alkyl group. Here, when the aliphatic dicarboxylic acid compound is an alkyl ester, the carbon number of the alkyl group is not included in the above carbon numbers.

[0019] From the perspective of hydrophobicity, the carbon number of the aliphatic dicarboxylic acid compound is preferably 4 or more, more preferably 8 or more, still more preferably 10 or more, and even more preferably 12 or more. From the perspective of low-temperature fixing property, it is preferably 16 or less, and more preferably 14 or less.

[0020] The aliphatic dicarboxylic acid compound may be a saturated aliphatic dicarboxylic acid compound or an unsaturated aliphatic dicarboxylic acid compound, but from the perspective of storage stability, it is preferably a saturated aliphatic dicarboxylic acid compound.

[0021] The content of the aliphatic dicarboxylic acid-based compound is preferably 80 mol% or more, more preferably 90 mol% or more, and 100 mol% or less from the viewpoint of hydrophobicity in the carboxylic acid component. When the carboxylic acid component contains a monocarboxylic acid-based compound, it is preferably 98 mol% or less, more preferably 95 mol% or less.

[0022] Examples of other carboxylic acid components include aromatic dicarboxylic acid-based compounds such as phthalic acid, isophthalic acid, and terephthalic acid, and polyvalent carboxylic acid-based compounds such as trimellitic acid and pyromellitic acid.

[0023] Furthermore, the alcohol component and / or carboxylic acid component of the crystalline polyester resin C preferably contains a monofunctional monomer.

[0024] Examples of the monofunctional monomer contained in the alcohol component include aliphatic monoalcohols such as capryl alcohol, capric alcohol, lauryl alcohol, myristyl alcohol, palmityl alcohol, stearyl alcohol, and behenyl alcohol.

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

[0026] From the viewpoint of improving hydrophobicity, the monofunctional monomer preferably contains an aliphatic monocarboxylic acid-based compound and / or an aliphatic monoalcohol.

[0027] From the viewpoint of hydrophobicity, the number of carbon atoms of the aliphatic monoalcohol is preferably 6 or more, more preferably 9 or more, still more preferably 10 or more, still more preferably 12 or more, and from the viewpoint of low-temperature fixability, it is preferably 24 or less, more preferably 23 or less, still more preferably 22 or less.

[0028] From the perspective of hydrophobicity, the number of carbon atoms in the aliphatic monocarboxylic acid compound is preferably 6 or more, more preferably 9 or more, and still more preferably 10 or more. From the perspective of low-temperature fixability, it is preferably 24 or less, more preferably 23 or less, and still more preferably 22 or less. Here, when the aliphatic monocarboxylic acid compound is an alkyl ester, the number of carbon atoms in the alkyl group is not included in the above number of carbon atoms.

[0029] The content of the monofunctional monomer is preferably 2 mol% or more, more preferably 3 mol% or more, and still more preferably 5 mol% or more in the total amount of the alcohol component and the carboxylic acid component. From the perspective of low-temperature fixability, it is preferably 30 mol% or less, more preferably 25 mol% or less, and still more preferably 20 mol% or less.

[0030] In this specification, macromonomers and hydroxycarboxylic acids are not included in the alcohol component and the carboxylic acid component.

[0031] The equivalent ratio of the carboxy group of the carboxylic acid component to the hydroxy group of the alcohol component (COOH group / OH group) is preferably 0.8 or more, more preferably 0.9 or more from the perspective of storage stability. From the perspective of low-temperature fixability, it is preferably 1.2 or less, more preferably 1.1 or less.

[0032] The crystalline polyester resin C 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 further, if necessary, in the presence of a cocatalyst, a polymerization inhibitor, etc., preferably at a temperature of 120°C or more and 230°C or less.

[0033] Examples of the esterification catalyst include tin compounds such as dibutyltin oxide and tin(II) 2-ethylhexanoate, and titanium compounds such as titanium diisopropoxybis(triethanolamineate). The amount of the esterification catalyst used is preferably 0.01 part by mass or more, more preferably 0.1 part by mass or more, and preferably 1.5 parts by mass or less, more preferably 1 part by mass or less, based on 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. Examples of the cocatalyst for the esterification catalyst include gallic acid. The amount of the cocatalyst 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, based on 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. Examples of the polymerization inhibitor include tert-butylcatechol. The amount of the 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, based on 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component.

[0034] In the present invention, the polyester resin may be a polyester resin modified to such an extent that its properties are not substantially impaired. Examples of the modified polyester resin include polyester resins grafted or blocked with phenol, urethane, epoxy, etc. by the methods described in JP-A-11-133668, JP-A-10-239903, JP-A-8-20636, etc. Among the modified polyester resins, a urethane-modified polyester resin obtained by extending a polyester resin with a polyisocyanate compound is preferred.

[0035] From the viewpoint of storage stability, the softening point of the crystalline polyester resin C is preferably 50°C or higher, more preferably 65°C or higher, still more preferably 70°C or higher, and from the viewpoint of low-temperature fixability, it is preferably 120°C or lower, more preferably 110°C or lower.

[0036] The crystallinity of the resin is represented by a crystallinity index defined as the ratio of the softening point to the maximum peak temperature of endotherm measured by a differential scanning calorimeter, i.e., [softening point / maximum peak temperature of endotherm]. The crystalline resin is a resin having a crystallinity index of 0.6 or more, preferably 0.7 or more, more preferably 0.9 or more, and 1.4 or less, preferably 1.2 or less, more preferably 1.1 or less. On the other hand, the amorphous resin is a resin in which no endothermic peak is observed, or if an endothermic peak is observed, the crystallinity index exceeds 1.4, preferably exceeds 1.5, more preferably is 1.6 or more, or is less than 0.6, preferably 0.5 or less. The crystallinity of the resin can be adjusted by the type and ratio of the raw material monomers, and production conditions (e.g., reaction temperature, reaction time, cooling rate), etc. The maximum peak temperature of endotherm refers to the temperature of the peak with the largest peak area among the observed endothermic peaks. In the case of a crystalline resin, the maximum peak temperature of endotherm is taken as the melting point.

[0037] From the viewpoint of storage stability, the melting point of the crystalline polyester resin C is preferably 60°C or higher, more preferably 70°C or higher, and from the viewpoint of low-temperature fixability, it is preferably 130°C or lower, more preferably 120°C or lower.

[0038] From the viewpoint of low-temperature fixability, the content of the crystalline polyester resin C is preferably 3% by mass or more, more preferably 5% by mass or more, still more preferably 8% by mass or more in the total amount of the crystalline polyester resin C and the amorphous polyester resin A, and from the viewpoint of storage stability, it is preferably 40% by mass or less, more preferably 30% by mass or less, still more preferably 20% by mass or less.

[0039] As the amorphous polyester resin A, an amorphous polyester resin or an amorphous composite resin in which a polyester resin and a styrene resin are bonded is preferable.

[0040] As the amorphous polyester resin, a polycondensate of an alcohol component containing an alkylene oxide adduct of bisphenol A and a carboxylic acid component is preferred.

[0041] As the alkylene oxide adduct of bisphenol A, the formula (I):

[0042] [Chemical formula]

[0043] (In the formula, OR and RO are oxyalkylene groups, R is an ethylene group and / or a propylene group, x and y represent the average number of moles of alkylene oxide added, and are each a positive number. The value of 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 still more preferably 4 or less) The compound represented by is preferred.

[0044] From the viewpoint of low-temperature fixability, the content of the alkylene oxide adduct of bisphenol A is preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, still more preferably 95 mol% or more, and still more preferably 100 mol% in the alcohol component.

[0045] Examples of other alcohol components include aliphatic diols, diols such as bisphenol A and hydrogenated bisphenol A, and polyhydric alcohols having three or more hydroxyl groups such as sorbitol, pentaerythritol, glycerin, and trimethylolpropane.

[0046] Examples of the carboxylic acid component include aromatic dicarboxylic acid compounds, aliphatic dicarboxylic acid compounds, and polycarboxylic acid compounds having three or more carboxyl groups.

[0047] Examples of the 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.

[0048] Examples of the aliphatic dicarboxylic acid compounds include fumaric acid, maleic acid, succinic acid, succinic acid derivatives substituted with hydrocarbon groups, glutaric acid, adipic acid, sebacic acid, anhydrides of these acids, alkyl esters of these acids having 1 to 3 carbon atoms, and the like.

[0049] Examples of the carboxylic acid compounds having a valency of 3 or more include trimellitic acid, pyromellitic acid, anhydrides of these acids, alkyl esters of these acids having 1 to 3 carbon atoms, and the like.

[0050] Note that the alcohol component may appropriately contain a monohydric alcohol, and the carboxylic acid component may appropriately contain a monohydric carboxylic acid compound.

[0051] The equivalent ratio (COOH group / OH group) of the carboxy group of the carboxylic acid component to the hydroxyl group of the alcohol component is preferably 0.6 or more, more preferably 0.7 or more, still more preferably 0.8 or more, and preferably 1.3 or less, more preferably 1.2 or less, from the viewpoint of adjusting the softening point of the polyester resin and the like.

[0052] 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, except that a suitable reaction temperature is 160°C or higher, more preferably 180°C or higher, and 250°C or lower, more preferably 240°C or lower.

[0053] The polyester resin in the composite resin is the same as the amorphous polyester resin described above, and the styrene resin is an addition polymer of a raw material monomer 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").

[0054] A styrene compound, preferably the styrene content, from the viewpoint of storage stability, is preferably 50% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more in the raw material monomers of the styrene resin, and from the viewpoint of low-temperature fixability, is preferably 95% by mass or less, more preferably 93% by mass or less, still more preferably 90% by mass or less.

[0055] Further, the styrene resin may contain a (meth)acrylic acid alkyl ester having 7 or more carbon atoms in the alkyl group as a raw material monomer. Examples of the (meth)acrylic acid alkyl ester include 2-ethylhexyl (meth)acrylate, (iso)octyl (meth)acrylate, (iso)decyl (meth)acrylate, (iso)stearyl (meth)acrylate, and the like. It is preferable to use one or more of these. In the present specification, “(iso)” means including both the case where this group is present and the case where it is not, and when these groups are not present, it indicates normal. Further, “(meth)acrylic acid” indicates acrylic acid, methacrylic acid, or both of them.

[0056] The number of carbon atoms in the alkyl group of the (meth)acrylic acid alkyl ester as a raw material monomer of the styrene resin is preferably 7 or more, more preferably 8 or more, from the viewpoint of improving the low-temperature fixability of the toner, and is preferably 18 or less, more preferably 12 or less. Note that the number of carbon atoms of the alkyl ester refers to the number of carbon atoms derived from the alcohol component constituting the ester.

[0057] The raw material monomers of the styrene resin may include raw material monomers other than styrene compounds and (meth)acrylic acid alkyl esters, such as 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; N-vinyl compounds such as N-vinylpyrrolidone, etc.

[0058] The addition polymerization reaction of the raw material monomers of the styrene resin can be carried out by a conventional method, for example, in the presence of a polymerization initiator such as dibutyl peroxide and dicumyl peroxide, a chain transfer agent, a crosslinking agent, etc., in the presence of an organic solvent or without a solvent. As the temperature condition, it is preferably 110 °C or higher, more preferably 140 °C or higher, and preferably 200 °C or lower, more preferably 170 °C or lower.

[0059] 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 with respect to 100 parts by mass of the raw material monomers of the styrene resin.

[0060] The composite resin is preferably a resin in which a polyester resin and a styrene resin are combined, and more preferably a resin in which the polyester resin and the styrene resin are chemically bonded through a bifunctional monomer capable of reacting with both the raw material monomers of the polyester resin and the raw material monomers of the styrene resin.

[0061] The bifunctional monomer preferably is a compound having, in the molecule, at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an epoxy group, a primary amino group and a secondary amino group, preferably a hydroxyl group and / or a carboxyl group, more preferably a carboxyl group, and an ethylenically unsaturated bond. At least one selected from the group consisting of acrylic acid, methacrylic acid, fumaric acid, maleic acid and maleic anhydride is more preferable, and at least one selected from the group consisting of acrylic acid, methacrylic acid and fumaric acid is even more preferable from the viewpoint of the reactivity of the polycondensation reaction and the addition polymerization reaction. 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 of the polyester resin. In this case, fumaric acid or the like is not a bifunctional monomer but a raw material monomer of the polyester resin.

[0062] From the viewpoint of enhancing the dispersibility of the styrene resin and the polyester resin and improving the dispersibility of the raw materials in the toner, the amount of the bifunctional monomer used is preferably 1 mol or more, more preferably 2 mol or more, per 100 mol in total of the alcohol components of the polyester resin, and from the viewpoint of improving the low-temperature fixability of the toner, it is preferably 30 mol or less, more preferably 20 mol or less, and even more preferably 10 mol or less.

[0063] Specifically, the composite resin is preferably produced by the following method. When using a bifunctional monomer, the bifunctional monomer is preferably used together with the raw material monomer of the styrene resin from the viewpoint of improving the dispersibility of the raw materials in the toner and the low-temperature fixability of the toner.

[0064] (i) A method in which after the step (A) of the polycondensation reaction with the raw material monomer of the polyester resin, the step (B) of the addition polymerization reaction with the raw material monomer of the styrene resin is carried out In this method, step (A) is carried out under reaction temperature conditions suitable for the polycondensation reaction, the reaction temperature is lowered, and step (B) is carried out under temperature conditions suitable for the addition polymerization reaction. The raw material monomers of the styrene resin are preferably added into the reaction system at a temperature suitable for the addition polymerization reaction. When both reactive monomers are used together with the raw material monomers of the styrene resin, the both reactive monomers undergo an addition polymerization reaction and also react with the polyester resin. After step (B), the reaction temperature is raised again, and if necessary, raw material monomers of a polyester resin having a trivalent or higher valency serving as a crosslinking agent and the like are added to the polymerization system, and the polycondensation reaction in step (A) and the reaction with both reactive monomers can be further advanced.

[0065] (ii) A method in which, after step (B) of the addition polymerization reaction using the raw material monomers of the styrene resin, step (A) of the polycondensation reaction using the raw material monomers of the polyester resin is carried out In this method, step (B) is carried out under reaction temperature conditions suitable for the addition polymerization reaction, the reaction temperature is raised, and the polycondensation reaction of step (A) is carried out under temperature conditions suitable for the polycondensation reaction. When both reactive monomers are used together with the raw material monomers of the styrene resin, the both reactive monomers are involved in both the addition polymerization reaction and the polycondensation reaction. The raw material monomers of 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 adjusted by adding an esterification catalyst at a temperature suitable for the polycondensation reaction.

[0066] (iii) A method in which the reaction is carried out under conditions where step (A) of the polycondensation reaction using the raw material monomers of the polyester resin and step (B) of the addition polymerization reaction using the raw material monomers of the styrene resin proceed in parallel In this method, step (A) and step (B) are carried out in parallel under reaction temperature conditions suitable for addition polymerization reaction, the reaction temperature is raised, and under temperature conditions suitable for polycondensation reaction, a raw material monomer of a polyester resin having a trivalent or higher valency serving as a crosslinking agent is added to the polymerization system as needed, and the polycondensation reaction of step (A) is further carried out. At that time, under temperature conditions suitable for the polycondensation reaction, a polymerization inhibitor can also be added to proceed only with the polycondensation reaction. When both reactive monomers are used, both reactive monomers are involved in the polycondensation reaction as well as the addition polymerization reaction.

[0067] In the method of (i) above, instead of the step (A) of carrying out the polycondensation reaction, a previously polymerized polyester resin may be used. In the method of (iii) above, when the reaction is carried out under conditions where step (A) and step (B) proceed in parallel, a mixture containing a raw material monomer of a styrene resin can also be dropped into a mixture containing a raw material monomer of a polyester resin and reacted.

[0068] The methods of (i) to (iii) above are preferably carried out in the same container.

[0069] The mass ratio of the polyester resin to the styrene resin in the composite resin (polyester resin / styrene resin) is preferably 98 / 2 or less, more preferably 95 / 5 or less, still more preferably 90 / 10 or less from the viewpoint of improving the dispersibility of the raw materials in the toner, and preferably 60 / 40 or more, more preferably 70 / 30 or more, still more preferably 75 / 25 or more from the viewpoint of low-temperature fixability. In the above calculation, the mass of the polyester resin is the amount obtained by subtracting the amount of reaction water (calculated value) dehydrated by the polycondensation reaction from the mass of the raw material monomer of the polyester resin used, and the amount of both reactive monomers is included in the amount of the raw material monomer of the polyester resin. Also, the amount of the styrene resin is the total amount of the raw material monomers of the styrene resin.

[0070] From the perspective of charge stability, the softening point of the amorphous polyester resin A is preferably 70°C or higher, more preferably 90°C or higher, still more preferably 100°C or higher, and from the perspective of low-temperature fixability, it is preferably 150°C or lower, more preferably 130°C or lower, still more preferably 115°C or lower.

[0071] From the perspective of storage stability, the glass transition temperature of the amorphous polyester resin A is preferably 40°C or higher, more preferably 50°C or higher, and from the perspective of low-temperature fixability, it is preferably 80°C or lower, more preferably 70°C or lower.

[0072] From the perspective of charge stability, the content of the amorphous polyester resin A in the total amount of the crystalline polyester resin C and the amorphous polyester resin A is preferably 60% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, and preferably 97% by mass or less, more preferably 95% by mass or less, still more preferably 92% by mass or less.

[0073] From the perspective of durability, the mass ratio of the amorphous polyester resin A to the crystalline polyester resin C in the toner (amorphous polyester resin A / crystalline polyester resin C) is preferably 60 / 40 or more, more preferably 70 / 30 or more, still more preferably 80 / 20 or more, and preferably 97 / 3 or less, more preferably 95 / 5 or less, still more preferably 92 / 8 or less.

[0074] In the toner, the crystalline polyester resin C and the amorphous polyester resin A are contained as a binder resin.

[0075] Examples of other binder resins include vinyl resins such as styrene acrylic resins, epoxy resins, polycarbonates, polyurethanes, and composite resins containing two or more of these resins.

[0076] The total content of the crystalline polyester resin C and the amorphous polyester resin A is preferably 70% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, still more preferably 95% by mass or more, and still more preferably 100% by mass in the binder resin.

[0077] Also, the content of the binder resin is preferably 60% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more in the toner, and is preferably 99% by mass or less, more preferably 98% by mass or less, still more preferably 95% by mass or less.

[0078] In addition to the binder resin, the electrostatic charge image developing toner of the present invention may contain additives such as a colorant, a release agent, a charge control agent, magnetic powder, a fluidity improver, a conductivity adjuster, a reinforcing filler such as a fibrous substance, an antioxidant, and a cleaning property improver.

[0079] As the colorant, dyes, pigments, magnetic materials, etc. used as colorants for toners can be used. For example, 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. may be mentioned. In the present invention, the toner may be either a black toner or a color toner.

[0080] 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 is preferably 40 parts by mass or less, more preferably 20 parts by mass or less, still more preferably 10 parts by mass or less with respect to 100 parts by mass of the binder resin.

[0081] 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 their oxides; ester waxes such as carnauba wax, montan wax, and their deacidified waxes, and fatty acid ester waxes; fatty acid amides, fatty acids, higher alcohols, fatty acid metal salts, etc. These can be used alone or in combination of two or more.

[0082] From the viewpoint of charge stability, the melting point of the release agent is preferably 60°C or higher, more preferably 70°C or higher, and from the viewpoint of low-temperature fixability, it is preferably 160°C or lower, more preferably 140°C or lower, still more preferably 120°C or lower, and even more preferably 110°C or lower.

[0083] From the viewpoints of the charge stability of the toner and the dispersibility in the binder resin, the content of the release agent is preferably 0.5 part by mass or more, more preferably 1 part by mass or more, still more preferably 1.5 parts by mass or more, per 100 parts by mass of the binder resin, and is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, still more preferably 7 parts by mass or less.

[0084] The charge control agent is not particularly limited, and may contain either a positive charge control agent or a negative charge control agent.

[0085] Examples of positive 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", "Bontron N-11", "Bontron N-79" (manufactured by Orient Chemical Industries, Ltd.); triphenylmethane dyes containing a tertiary amine in the side chain; quaternary ammonium salt compounds such as "Bontron P-51" (manufactured by Orient Chemical Industries, Ltd.), cetyltrimethylammonium bromide, "COPY CHARGE PX VP435" (manufactured by Clariant); polyamine resins such as "AFP-B" (manufactured by Orient Chemical Industries, Ltd.); imidazole derivatives such as "PLZ-2001", "PLZ-8001" (manufactured by Shikoku Kasei Kogyo Co., Ltd.); styrene-acrylic resins such as "FCA-701PT", "FCA-201-PS" (manufactured by Fujikura Kasei Co., Ltd.).

[0086] Examples of negative charge control agents include metal-containing azo dyes such as "Vari Fast Black 3804", "Bontron S-31", "Bontron S-32", "Bontron S-34", "Bontron S-36" (manufactured by Orient Chemical Industries, Ltd.), "Eisenspirone Black TRH", "T-77" (manufactured by Hodogaya Chemical Co., Ltd.); metal compounds of benzoic acid compounds such as "LR-147", "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", "Bontron E-304" (manufactured by Orient Chemical Industries, Ltd.), "TN-105" (manufactured by Hodogaya Chemical Co., Ltd.); copper phthalocyanine dyes; quaternary ammonium salts such as "COPY CHARGE NX VP434" (manufactured by Clariant), nitroimidazole derivatives; and organometallic compounds.

[0087] From the viewpoint of the charging stability of the toner, the content of the charge control agent is preferably 0.01 part by mass or more, more preferably 0.2 part by mass or more, and preferably 10 parts by mass or less, more preferably 5 parts by mass or less, still more preferably 3 parts by mass or less, and still more preferably 2 parts by mass or less, based on 100 parts by mass of the binder resin.

[0088] 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 resin fine particles and polytetrafluoroethylene resin fine particles. Two or more of them may be used in combination. Among these, silica is preferable, and from the viewpoint of the transferability of the toner, hydrophobized hydrophobic silica is more preferable.

[0089] Examples of the hydrophobizing agent for hydrophobizing the surface of silica particles include hexamethyldisilazane (HMDS), dimethyldichlorosilane (DMDS), cyclic silazane, silicone oil, aminosilane, octyltriethoxysilane (OTES), and methyltriethoxysilane.

[0090] From the viewpoints of the chargeability, fluidity, and transferability of the toner, the average particle diameter of the external additive is preferably 10 nm or more, more preferably 15 nm or more, and preferably 250 nm or less, more preferably 200 nm or less, and still more preferably 90 nm or less.

[0091] From the viewpoints of the chargeability, fluidity, and transferability of the toner, the content of the external additive is preferably 0.05 part by mass or more, more preferably 0.1 part by mass or more, and still more preferably 0.3 part by mass or more, based on 100 parts by mass of the toner mother particles, and preferably 5 parts by mass or less, more preferably 3 parts by mass or less.

[0092] In the present invention, the toner mother particles may be toner obtained by any conventionally known method such as a melt-kneading method, an emulsion aggregation method, or a suspension polymerization method. However, from the viewpoint of more significantly exhibiting the effects of the present invention, it is preferable to manufacture by the melt-kneading method.

[0093] Therefore, the toner of the present invention is obtained by a method including a step of melt-kneading a mixture containing a crystalline polyester resin C, an amorphous polyester resin A, and, if necessary, additives such as a colorant, a release agent, and a charge control agent (melt-kneading step), a step of pulverizing and classifying the obtained kneaded product to obtain toner mother particles (pulverizing and classifying step), and a step of mixing the obtained toner mother particles with an external additive (external addition step).

[0094] The mixture to be melt-kneaded may be melt-kneaded all at once or dividedly, but it is preferably mixed in advance with a mixer such as a Henschel mixer or a ball mill and then supplied for melt-kneading.

[0095] For melt-kneading, known kneading machines such as a closed kneader, a single-screw or twin-screw extruder, and an open roll kneader can be used.

[0096] After melt-kneading, it is preferable to appropriately cool the kneaded product until it reaches a hardness that can be pulverized and then perform the pulverizing and classifying step to obtain toner mother particles. Here, cooling means cooling the kneaded product to 0°C or higher and 50°C or lower, or cooling it to a temperature equal to or lower than the glass transition temperature of the binder resin in the kneaded product.

[0097] In the pulverization of the kneaded product, the kneaded product may be pulverized at once to a desired particle size or stepwise, but from the viewpoints of efficient and more uniform pulverization, it is preferably performed in two stages of coarse pulverization and fine pulverization.

[0098] Examples of the pulverizer used for coarse pulverization include a hammer mill, a cutter mill, an atomizer, and a rotor plex.

[0099] In coarse pulverization, it is preferable to pulverize until the maximum diameter becomes 3 mm or less, more preferably 2 mm or less. For example, a pulverized product with a maximum diameter of 3 mm or less can be obtained by appropriately coarsely pulverizing the kneaded product until the particle size becomes about 0.05 mm or more and 3 mm or less and then passing it through a sieve with a mesh size of 3 mm.

[0100] Examples of the grinder used for fine grinding include jet mills such as fluidized bed jet mills and impact plate jet mills, and mechanical mills.

[0101] The degree of fine grinding is preferably adjusted as appropriate according to the particle size of the target toner mother particles.

[0102] Examples of the classifier used for classification include air classifiers, inertial classifiers, and sieve classifiers. During the classification process, the ground material that has not been sufficiently ground and removed may be returned to the grinding process, and the grinding process and the classification process may be repeated as necessary.

[0103] The external addition process of mixing the toner mother particles and the external additive can be performed according to a conventional method, and a mixer such as a Henschel mixer can be used.

[0104] The toner of the present invention can be used as a one-component developer toner as it is, or as a two-component developer toner mixed with a carrier, and can be used in an image forming apparatus using a one-component development method or a two-component development method, respectively.

Examples

[0105] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited by these examples. The physical properties of resins and the like can be measured by the following methods.

[0106] 〔Softening point of resin〕 Using a flow tester "CFT-500D" (manufactured by Shimadzu Corporation), while heating 1 g of the sample at a heating rate of 6°C / min, a load of 1.96 MPa is applied by a plunger and extruded from a nozzle with a diameter of 1 mm and a length of 1 mm. The plunger descent amount of the flow tester is plotted against the temperature, and the temperature at which half of the sample has flowed out is taken as the softening point.

[0107] 〔Maximum peak temperature of endotherm of resin〕 Using a differential scanning calorimeter "Q-100" (manufactured by TA Instruments Japan Co., Ltd.), weigh 0.01 to 0.02 g of the sample into an aluminum pan, cool it from room temperature (25°C) to 0°C at a cooling rate of 10°C / min, and maintain it at 0°C for 1 minute. Then, measure it at a heating rate of 10°C / min. Among the observed endothermic peaks, the temperature of the peak with the largest peak area is defined as the maximum endothermic peak temperature. For a crystalline resin, the maximum endothermic peak temperature is defined as the melting point.

[0108] 〔Glass transition temperature of resin〕 Using a differential scanning calorimeter "Q-100" (manufactured by TA Instruments Japan Co., Ltd.), weigh 0.01 to 0.02 g of the sample into an aluminum pan, heat it up to 200°C, and then cool it from that temperature to 0°C at a cooling rate of 10°C / min. Next, heat the sample up to 150°C at a heating rate of 10°C / min and measure the endothermic peak. The temperature at the intersection of the extension line 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.

[0109] 〔Melting point of release agent〕 Using a differential scanning calorimeter "Q-100" (manufactured by TA Instruments Japan Co., Ltd.), weigh 0.02 g of the sample into an aluminum pan, heat it up to 200°C, and then cool it from 200°C to 0°C at a cooling rate of 10°C / min. Then, heat the sample up at a heating rate of 10°C / min, measure the heat quantity, and define the maximum endothermic peak temperature as the melting point.

[0110] 〔Number particle size distribution, number median particle diameter (D 50 ) and coefficient of variation (CV value) of toner mother 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" (manufactured by Beckman Coulter, Inc.) · Electrolyte: "Isoton (registered trademark) II" (manufactured by Beckman Coulter, Inc.) · Dispersion: A solution prepared by dissolving polyoxyethylene lauryl ether "Emulgen (registered trademark) 109P" [manufactured by Kao Corporation, HLB (Griffin) = 13.6] in an electrolyte to adjust the concentration to 5% by mass. · Dispersion conditions: Add 10 mg of the measurement sample to 5 mL of the above dispersion, disperse it for 1 minute with an ultrasonic disperser (machine name: US-1 manufactured by SND Co., Ltd., output: 80 W), then add 25 mL of the electrolyte, and further disperse it for 1 minute with the ultrasonic disperser to prepare a sample dispersion. · Measurement conditions: By adding the sample dispersion to 100 mL of the electrolyte, adjust the concentration to a level where the particle size of 30,000 particles can be measured in 20 seconds, then measure 30,000 particles, and from the particle size distribution, determine the number median particle size (D 50 ) and the volume average particle size (D V ). Also, the coefficient of variation (CV) value (%) is calculated according to the following formula. CV value (%) = (standard deviation of the particle size distribution / volume average particle size (D V )) × 100

[0111] 〔Average particle size of the external additive〕 The average particle size refers to the number average particle size. Measure the particle sizes (average value of the major axis and minor axis) of 500 particles from a scanning electron microscope (SEM) photograph and take their number average value.

[0112] Production Example 1 of alkenyl succinic anhydride (1) Using propylene tetramer (manufactured by Nippon Oil Corporation, trade name: "Light Tetramer"), it was fractionated under heating conditions of 183 to 208 °C to obtain an alkylene compound (a). The obtained alkylene compound (a) had 40 peaks in the following gas chromatography-mass spectrometry. The distribution of the alkylene compound was measured according to the analysis by gas chromatography-mass spectrometry of alkylene compound A in JP-A-2014-013384, and C9H 18 : 0.5% by mass, C 10 H 20 : 4% by mass, C 11 H 22 : 20% by mass, C 12 H 24 : 66% by mass, C13 H 26 : 9 mass%, C 14 H 28 : 0.5 mass% (the number of peaks corresponding to an alkylene compound having 9 to 14 carbon atoms was 6).

[0113] (2) 542.4 g of alkylene compound (a), 157.2 g of maleic anhydride, 0.4 g of antioxidant "Chelex - O" (manufactured by SC Organic Chemical Co., Ltd., Triisooctyl phosphite), and 0.1 g of butylhydroquinone as a polymerization inhibitor were charged into a 1 L autoclave manufactured by Nitto Koki Co., Ltd. The pressure replacement with pressurized nitrogen (0.2 MPaG) was repeated three times. After starting stirring at 60°C, the temperature was raised to 230°C over 1 hour and reacted for 6 hours. The pressure at the time of reaching the reaction temperature was 0.3 MPaG. After the reaction was completed, it was cooled to 80°C, returned to normal pressure (101.3 kPa), and transferred to a 1 - liter four - necked flask. The temperature was raised to 180°C with stirring, and the remaining alkylene compound was distilled off at 1.3 kPa in 1 hour. Subsequently, after cooling to room temperature (25°C) and returning to normal pressure (101.3 kPa), 406.1 g of the target alkenyl succinic anhydride A was obtained. The average molecular weight of alkenyl succinic anhydride A determined from the acid value was 268.

[0114] Resin Production Example 1 The alcohol component, carboxylic acid component, and esterification catalyst shown in Table 1 were placed in a 5 - liter four - necked flask equipped with a nitrogen introduction tube, a stirrer, and a thermocouple. After raising the temperature to 235°C under a nitrogen atmosphere, polycondensation was carried out at 235°C for 6 hours. Then, the temperature was lowered to 210°C, and the reaction was carried out under a reduced pressure of 10 kPa until the softening point described in Table 1 was reached to obtain amorphous polyester resins (Resins A1, A2). The physical properties are shown in Table 1

[0115] Resin Production Example 2 The alcohol component, carboxylic acid component other than trimellitic anhydride, and esterification catalyst shown in Table 1 were placed in a 5-liter four-necked flask equipped with a nitrogen inlet tube, a stirrer, and a thermocouple. After heating to 235°C under a nitrogen atmosphere, polycondensation was carried out at 235°C for 6 hours. Then, the temperature was lowered to 210°C, and the trimellitic anhydride shown in Table 1 was added. After reacting 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 1 was reached, to obtain an amorphous polyester resin (Resin A3). The physical properties are shown in Table 1.

[0116] Resin Production Example 3 The alcohol component, carboxylic acid component other than fumaric acid, and esterification catalyst shown in Table 1 were placed in a 5-liter four-necked flask equipped with a dehydration tube equipped with a nitrogen inlet tube, a stirrer, and a thermocouple. After heating to 235°C under a nitrogen atmosphere, polycondensation was carried out at 235°C for 6 hours. Then, the temperature was lowered to 160°C, and a mixture of both reactive monomers, raw material monomers of the styrene resin, and a polymerization initiator shown in Table 1 was added dropwise over 1 hour using a dropping funnel. After the dropping, while maintaining the temperature at 160°C, the addition polymerization reaction was aged for 1 hour, then raised to 200°C, and the pressure was reduced to 10 kPa for 1 hour. After releasing the pressure, the temperature was lowered to 180°C, fumaric acid and a polymerization inhibitor shown in Table 1 were added, held at 180°C for 1 hour, then the temperature was raised from 180°C to 210°C at 10°C / h, and reacted at 210°C for 1 hour. Further, the reaction was carried out at 210°C under a reduced pressure of 10 kPa until the softening point shown in Table 1 was reached, to obtain an amorphous composite resin (Resin A4). The physical properties are shown in Table 1.

[0117]

Table 1

[0118] Resin Production Example 4 The alcohol component and carboxylic acid component shown in Table 2 were placed in a 5-liter four-necked flask equipped with a thermometer, a stainless steel stirring rod, a reflux condenser, and a nitrogen inlet tube, and heated in a mantle heater in a nitrogen atmosphere to 200°C over 8 hours. Thereafter, 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, to obtain a crystalline polyester resin (Resins C1 to C4). The physical properties are shown in Table 2.

[0119]

Table 2

[0120] Examples 1 to 12 and Comparative Examples 1 to 3 100 parts by mass of the binder resin shown in Table 3, 3 parts by mass of the release agent "Carnauba Wax C1" (manufactured by Kato Yoko Co., Ltd., melting point: 83°C), 5 parts by mass of the colorant "ECB-301" (manufactured by Dainichi Seika Co., Ltd., phthalocyanine blue (P.B.15:3)), and 0.5 parts by mass of the charge control agent "Bontron E-304" (manufactured by Orient Chemical Industries Co., Ltd.) were mixed for 1 minute using a Henschel mixer and then melt-kneaded under the conditions shown below.

[0121] A co-rotating twin-screw extruder "PCM-30" (manufactured by Ikegai Corporation, shaft diameter 2.9 cm, shaft cross-sectional area 7.06 cm 2 ) was used. The operating conditions were a barrel set temperature of 100°C, a shaft rotation speed of 200 r / min (circumferential speed of shaft rotation 0.30 m / sec), and a mixture supply rate of 10 kg / h (mixture supply amount per unit cross-sectional area of shaft 1.42 kg / h·cm 2 ).

[0122] After cooling the obtained kneaded product to about 25°C, it was roughly pulverized with a pulverizer "Rotoplex" (manufactured by Hosokawa Micron Corporation), and a roughly pulverized product with a maximum diameter of 2 mm or less was obtained by passing through a sieve with an opening of 2 mm. This roughly pulverized product was finely pulverized using a DS2 type air classifier (impact plate type, manufactured by Nippon Pneumatic Mfg. Co., Ltd.), and then using a DSX2 type air classifier (manufactured by Nippon Pneumatic Mfg. Co., Ltd.), the number median particle diameter (D 50 ) and from 0 μm to (D 50Classification was performed by adjusting the static pressure (internal pressure) so that the particle ratio reached up to -2.0) μm, and toner mother particles were obtained.

[0123] 100 parts by mass of the obtained toner mother particles, 0.5 part by mass of hydrophobic silica "R972" (manufactured by Nippon Aerosil Co., Ltd., hydrophobizing agent: DMDS, average particle size: 16 nm), and 1 part by mass of hydrophobic silica "RY50" (manufactured by Nippon Aerosil Co., Ltd., hydrophobizing agent: silicone oil, average particle size: 40 nm) as external additives were mixed in a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.) at 2100 r / min (peripheral speed 29 m / sec) for 3 minutes to obtain toner.

[0124] Test Example 1 [Low-temperature fixability] The printer "OKI MICROLINE 5400" (manufactured by Oki Electric Industry Co., Ltd.) modified to be able to obtain an unfixed image was filled with toner, and an unfixed image of a solid image with a size of 2 cm square was printed. Using an externally fixed device modified from "OKI MICROLINE 3010" (manufactured by Oki Electric Industry Co., Ltd.), while raising the temperature of the fixing roll from 100 °C to 230 °C in 5 °C increments at a rotational speed of the fixing roll of 120 mm / sec, the fixing process of this unfixed image was performed at each temperature to obtain a fixed image. The images obtained at each fixing temperature were rubbed 5 times back and forth with a sanding rubber (manufactured by LION Co., Ltd., ER-502R) with a load of 500 g, and the image densities before and after rubbing were measured using a reflection densitometer "RD-915" (manufactured by GretagMacbeth). The temperature at which the image density ratio after rubbing ([image density after rubbing / image density before rubbing] × 100) first exceeded 85% was defined as the minimum fixing temperature and used as an index for low-temperature fixability. The results are shown in Table 3. The lower the minimum fixing temperature, the better the low-temperature fixability.

[0125] Test Example 2 [Durability under high temperature and high humidity] Toner was installed in the non-magnetic single-component developing device "OKI MICROLINE 5400" (manufactured by Oki Electric Industry Co., Ltd.), and a solid image of A4 size was printed under the conditions of a temperature of 30°C and a relative humidity of 90%. Next, after printing 500 sheets at a printing rate of 1%, a solid image of A4 size was printed again. Note that J paper (manufactured by Fujifilm Business Innovation Co., Ltd.) was used as the printing medium. The image density (ID1) of the central part 5 cm from the lower part of the initial black solid image and the image density (ID2) of the central part 5 cm from the lower part of the solid image after printing 500 sheets were measured using a reflection densitometer "RD-915" (manufactured by GretagMacbeth), and the difference in image density between the two (ID1-ID2) was confirmed. Printing at a printing rate of 1% was performed in increments of 500 sheets until the difference in image density exceeded 0.4, and the difference in image density of the solid image was confirmed every 500 sheets. The results are shown in Table 3. The higher the number of printed sheets, the better the durability.

[0126]

Table 3

[0127] From the above results, it can be seen that in Examples 1 to 12, the low-temperature fixing property and the durability under high temperature and high humidity are excellent. On the other hand, Comparative Example 1 with a large amount of fine powder and Comparative Example 2 with too small toner particle size lack durability, and it can be seen that Comparative Example 3 containing a crystalline polyester resin without using ethylene glycol is insufficient in both low-temperature fixing property and durability.

Industrial Applicability

[0128] The toner for developing an electrostatic charge image of the present invention is suitably used for developing a latent image formed in an electrophotographic method, an electrostatic recording method, an electrostatic printing method, etc.

Claims

1. An electrostatic charge image developing toner containing toner mother particles containing a crystalline polyester resin C and an amorphous polyester resin A and an external additive, wherein the crystalline polyester resin C is a polycondensate of an alcohol component containing 60 mol% or more of ethylene glycol and a carboxylic acid component containing an aliphatic dicarboxylic acid compound, and the number median particle diameter (D ５０ ) is 5.0 μm or more and 10.0 μm or less, and the proportion of particles from 0 μm to (D ５０ - 2.0) μm is 9.5% by number or less. An electrostatic charge image developing toner.

2. The electrostatic charge image developing toner according to claim 1, wherein the coefficient of variation (CV value) based on the volume particle size distribution of the toner mother particles is 14.0% or more and 18.0% or less.

3. A method for producing the electrostatic charge image developing toner according to claim 1 or 2, comprising a step of melt-kneading a mixture containing a crystalline polyester resin C and an amorphous polyester resin A, a step of pulverizing and classifying the obtained kneaded product to obtain toner mother particles, and a step of mixing the obtained toner mother particles and an external additive.

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