Manufacturing method of electrostatic charge image developing toner

Abstract

To provide a manufacturing method of an electrostatic charge image developing toner excellent in heat-resistant storage stability.SOLUTION: A manufacturing method of an electrostatic charge image developing toner includes a process of fusing and kneading a mixture which contains a binder resin, colorant, and a release agent. The binder resin contains a crystalline polyester resin with ester group concentration of 5.0 mmol / g or more and 10.0 mmol / g or less. When a value obtained by dividing the total number of -NH-groups and -NH2 groups in one molecule by molecular weight is set as NH group amount, the colorant contains an organic yellow pigment with the NH group amount of 3.0 mmol / g or more. The release agent contains a paraffin wax. The fusion and kneading of the mixture are performed by using an open-roll kneader.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for manufacturing 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, or the like.

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 that can cope with higher image quality and higher speed. For example, due to the higher 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, a crystalline polyester resin has been studied as a binder resin effective for improving the low-temperature fixability of the toner (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, toners containing a crystalline polyester resin have a problem that the heat-resistant storage stability is not stable.

[0006] The present invention relates to a method for manufacturing an electrostatic charge image developing toner having excellent heat-resistant storage stability.

Means for Solving the Problems

[0007] The present invention relates to a method for manufacturing an electrostatic charge image developing toner having a step of melt-kneading a mixture containing a binder resin, a colorant, and a release agent, wherein the binder resin contains a crystalline polyester resin having an ester group concentration of 5.0 mmol / g or more and 10.0 mmol / g or less, and the colorant contains an organic yellow pigment having an NH group amount of 3.0 mmol / g or more when the total number of -NH- groups and -NH 2 groups in one molecule divided by the molecular weight is defined as the NH group amount, and the release agent contains paraffin wax, and the melt-kneading of the mixture is performed using an open roll type kneader.

Advantages of the Invention

[0008] By the method of the present invention, an electrostatic charge image developing toner excellent in heat storage stability can be obtained.

Embodiments for Carrying Out the Invention

[0009] The present invention is a method for manufacturing an electrostatic charge image developing toner (hereinafter also simply referred to as "toner") through a step of melt-kneading a mixture containing a binder resin, a colorant, and a release agent, and is a method of melt-kneading a mixture containing a specific crystalline polyester resin, an organic yellow pigment, and a release agent using an open roll type kneader. The reason why a toner excellent in heat storage stability can be obtained by the method of the present invention is not clear, but it is presumed as follows. The following mechanism is a presumption and is not limited thereto.

[0010] As a result of intensive studies by the present inventors, it was considered that the decrease in heat storage stability was due to insufficient control of the formation of crystal domains of the crystalline polyester resin in the toner after melt-kneading (such as domain enlargement and poor dispersion). Therefore, by using an open roll kneader with a strong kneading share for melting and kneading the raw materials, and enhancing the dispersibility of the hydrophobic components, i.e., the crystalline polyester resin and wax (release agent), into the toner particles, the domain of the hydrophobic components in the toner particles can be refined. As a result, the refined crystalline polyester resin aggregates on the surface (hydrophobic field) of the wax domain enlarged by refinement, promoting crystallization. Therefore, as the wax, paraffin wax with higher hydrophobicity is preferred. Furthermore, by using an organic yellow pigment with a large amount of amino groups and controlling the ester group concentration of the crystalline polyester resin within a specific range, the interaction between the ester group of the crystalline polyester resin and the amino group of the yellow pigment works significantly, improving the affinity between the crystalline polyester resin and the yellow pigment. Thus, the yellow pigment is also finely dispersed in the toner together with the crystalline polyester resin. And this yellow pigment acts as a crystal nucleating agent, further promoting the crystal recovery of the crystalline polyester resin. Due to these effects, it is considered that the heat-resistant storage stability of the resulting toner is improved by quickly forming the crystal domain of the fine crystalline polyester resin.

[0011] In the present invention, the binder resin contains a crystalline polyester resin having a specific ester group concentration from the viewpoint of interaction with the organic yellow pigment as described above.

[0012] The ester group concentration of the crystalline polyester resin is 5.0 mmol / g or more, preferably 5.3 mmol / g or more, more preferably 5.6 mmol / g or more, and 10.0 mmol / g or less, preferably 9.5 mmol / g or less, more preferably 9.0 mmol / g or less. When using two or more kinds of crystalline polyester resins, the weighted average value of the ester group concentrations of each crystalline polyester resin is taken as the ester group concentration of the crystalline polyester resin.

[0013] In the present invention, the ester group concentration of the polyester resin is calculated from the following formula.

[0014]

Equation

[0015] [In the formula, A is the total amount (mol) of all ester bonds formed when all the raw material monomers of the polyester resin have reacted, and B is the total mass (g) of the raw material monomers constituting the polyester resin. In addition, the parentheses in the formula indicate the units of the respective numerical values.]

[0016] In the present invention, the crystalline polyester resin is preferably a polycondensate of an alcohol component containing an aliphatic diol and a carboxylic acid component containing an aliphatic dicarboxylic acid compound.

[0017] Examples of the aliphatic diol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-butenediol, 1,7-heptanediol, 1,8-octanediol, neopentyl glycol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol and the like.

[0018] The aliphatic diol has 2 or more carbon atoms, and from the viewpoint of adjusting the ester group concentration, it is preferably 14 or less, more preferably 10 or less, and still more preferably 8 or less.

[0019] From the viewpoint of improving the low-temperature fixability of the toner, the aliphatic diol preferably has a hydroxyl group at the end of the carbon chain, and is more preferably an α,ω-linear alkanediol.

[0020] The content of the aliphatic diol in the alcohol component is preferably 80 mol% or more, more preferably 90 mol% or more, still more preferably 95 mol% or more, and 100 mol% or less.

[0021] Examples of alcohol components other than aliphatic diols include alkylene oxide adducts of bisphenol A, aromatic diols such as bisphenol A, hydrogenated bisphenol A, sorbitol, pentaerythritol, glycerin, and polyhydric alcohols with three or more hydroxyl groups such as trimethylolpropane.

[0022] 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), anhydrides of these acids, and alkyl esters of these acids with an alkyl group having 1 to 3 carbon atoms. 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.

[0023] The carbon number of the aliphatic dicarboxylic acid compound is preferably 4 or more, more preferably 6 or more, still more preferably 8 or more, and from the viewpoint of adjusting the ester group concentration, it is preferably 14 or less.

[0024] The content of the aliphatic dicarboxylic acid compound is preferably 50 mol% or more, more preferably 60 mol% or more, still more preferably 70 mol% or more, and even more preferably 80 mol% or more from the viewpoint of hydrophobicity in the carboxylic acid component, and is 100 mol% or less.

[0025] Examples of other carboxylic acid components include aromatic dicarboxylic acid compounds such as phthalic acid, isophthalic acid, and terephthalic acid, and polycarboxylic acid compounds with three or more carboxyl groups such as trimellitic acid and pyromellitic acid.

[0026] Furthermore, from the viewpoint of durability, it is preferable that the alcohol component and / or carboxylic acid component of the crystalline polyester resin contains a monofunctional monomer.

[0027] Examples of the monofunctional monomers contained in the alcohol component include aliphatic monoalcohols such as capryl alcohol, lauryl alcohol, myristyl alcohol, palmityl alcohol, stearyl alcohol, and behenyl alcohol.

[0028] From the viewpoint of hydrophobicity, the number of carbon atoms of the aliphatic monoalcohol is preferably 10 or more, more preferably 12 or more, still more preferably 14 or more, and from the viewpoint of low-temperature fixability, it is preferably 22 or less, more preferably 20 or less, still more preferably 18 or less.

[0029] Examples of the monofunctional monomers contained in the carboxylic acid component include aliphatic monocarboxylic acids such as capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, and behenic acid, and aliphatic monocarboxylic acid-based compounds such as alkyl esters in which the number of carbon atoms of the alkyl group of these acids is 1 or more and 3 or less.

[0030] From the viewpoint of hydrophobicity, the number of carbon atoms of the aliphatic monocarboxylic acid-based compound is preferably 10 or more, more preferably 12 or more, still more preferably 14 or more, and from the viewpoint of low-temperature fixability, it is preferably 22 or less, more preferably 20 or less, still more preferably 18 or less. Here, when the aliphatic monocarboxylic acid-based compound is an alkyl ester, the number of carbon atoms of the alkyl group is not included in the above number of carbon atoms.

[0031] The content of the monofunctional monomer is preferably 1 mol% or more, more preferably 3 mol% or more, still more preferably 5 mol% or more in the total amount of the alcohol component and the carboxylic acid component, and from the viewpoint of low-temperature fixability, it is preferably 30 mol% or less, more preferably 20 mol% or less, still more preferably 15 mol% or less.

[0032] In addition, in this specification, macromonomers and hydroxycarboxylic acids are not included in the alcohol component and the carboxylic acid component.

[0033] 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 more, more preferably 0.9 or more, from the viewpoint of charge stability, and preferably 1.2 or less, more preferably 1.1 or less, from the viewpoint of low-temperature fixability.

[0034] The crystalline polyester resin 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 higher, more preferably 180°C or higher, and preferably 230°C or lower, more preferably 220°C or lower.

[0035] 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 0.05 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.

[0036] 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.

[0037] From the viewpoint of durability, the softening point of the crystalline polyester resin is preferably 50°C or higher, more preferably 55°C or higher, still more preferably 65°C or higher, and from the viewpoint of low-temperature fixability, it is preferably 140°C or lower, more preferably 120°C or lower, still more preferably 100°C or lower.

[0038] 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., the value of [softening point / maximum peak temperature of endotherm]. The crystalline resin has a crystallinity index of 0.6 or higher, preferably 0.7 or higher, more preferably 0.9 or higher, and is a resin of 1.4 or lower, preferably 1.2 or lower, more preferably 1.1 or lower. 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 higher, or is a resin of less than 0.6, preferably 0.5 or lower. 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.

[0039] From the perspective of durability, the melting point of the crystalline polyester resin is preferably 50 °C or higher, more preferably 55 °C or higher, still more preferably 65 °C or higher, and from the perspective of low-temperature fixability, it is preferably 130 °C or lower, more preferably 120 °C or lower, still more preferably 100 °C or lower.

[0040] From the perspective of low-temperature fixability, the acid value of the crystalline polyester resin is preferably 1 mgKOH / g or higher, more preferably 3 mgKOH / g or higher, and from the perspective of durability, it is preferably 20 mgKOH / g or lower, more preferably 15 mgKOH / g or lower.

[0041] From the perspective of low-temperature fixability, the content of the crystalline polyester resin in the binder resin is preferably 5% by mass or higher, more preferably 10% by mass or higher, still more preferably 15% by mass or higher, and from the perspective of durability, it is preferably 35% by mass or lower, more preferably 30% by mass or lower, still more preferably 25% by mass or lower.

[0042] From the perspective of heat-resistant storage stability, the binder resin preferably further contains an amorphous polyester resin.

[0043] As the amorphous polyester resin, an amorphous polyester resin or an amorphous composite resin in which a polyester resin and a styrene resin are bonded is preferable.

[0044] 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 preferable.

[0045] As the alkylene oxide adduct of bisphenol A, formula (I):

[0046]

Chemical formula

[0047] (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 positive numbers respectively. 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, still more preferably 4 or less.) The compound represented by is preferred.

[0048] From the viewpoint of low-temperature fixing property, the content of the alkylene oxide adduct of bisphenol A in the alcohol component is preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, still more preferably 95 mol% or more, and still more preferably 100 mol%.

[0049] Examples of other alcohol components include aliphatic diols, bisphenol A, hydrogenated bisphenol A, sorbitol, pentaerythritol, glycerin, and polyhydric alcohols having three or more valences such as trimethylolpropane.

[0050] Examples of the carboxylic acid component include aromatic dicarboxylic acid compounds, aliphatic dicarboxylic acid compounds, and polycarboxylic acid compounds having three or more valences.

[0051] 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.

[0052] 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, and alkyl esters of these acids having 1 to 3 carbon atoms.

[0053] Examples of the polycarboxylic acid compounds having three or more valences include trimellitic acid, pyromellitic acid, anhydrides of these acids, and alkyl esters of these acids having 1 to 3 carbon atoms.

[0054] In addition, the alcohol component may appropriately contain a monohydric alcohol, and the carboxylic acid component may appropriately contain a monohydric carboxylic acid compound.

[0055] 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 0.6 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.

[0056] 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 more, more preferably 180°C or more, and 250°C or less, more preferably 240°C or less.

[0057] The polyester resin in the composite resin is the same as the amorphous polyester resin described above. 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").

[0058] The content of the styrene compound, preferably styrene, in the raw material monomer of the styrene resin is preferably 50% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, from the viewpoint of storage stability, and preferably 95% by mass or less, more preferably 93% by mass or less, still more preferably 90% by mass or less, from the viewpoint of low-temperature fixability.

[0059] In addition, the styrene resin may contain an alkyl (meth)acrylate having 7 or more carbon atoms in the alkyl group as a raw material monomer. Examples of the alkyl (meth)acrylate 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” means acrylic acid, methacrylic acid, or both of them.

[0060] From the viewpoint of improving the low-temperature fixability of the toner, the number of carbon atoms in the alkyl group of the alkyl (meth)acrylate as a raw material monomer of the styrene resin is preferably 7 or more, more preferably 8 or more, and preferably 12 or less, more preferably 10 or less. The number of carbon atoms of the alkyl ester refers to the number of carbon atoms derived from the alcohol component constituting the ester.

[0061] The raw material monomers of the styrene resin may include raw material monomers other than styrene compounds and alkyl (meth)acrylates, for example, ethylenically unsaturated monoolefins such as ethylene and propylene; diolefins such as butadiene; halovinyls such as vinyl chloride; vinyl esters such as vinyl acetate and vinyl propionate; ethylenically 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, and the like.

[0062] The addition polymerization reaction of the raw material monomers of the styrene resin can be carried out by a conventional method in the presence of a polymerization initiator such as dibutyl peroxide, 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.

[0063] When using an organic solvent during 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.

[0064] The composite resin is preferably a resin in which a polyester resin and a styrene resin are bonded, and more preferably a resin in which the polyester resin and the styrene resin are chemically bonded via 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.

[0065] The bifunctional monomer preferably has 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 in the molecule, preferably a hydroxyl group and / or a carboxyl group, more preferably a carboxyl group, and an ethylenically unsaturated bond. A compound having these is preferred, and at least one selected from the group consisting of acrylic acid, methacrylic acid, fumaric acid, maleic acid, and maleic anhydride is more preferred. From the viewpoint of the reactivity of the polycondensation reaction and the addition polymerization reaction, at least one selected from the group consisting of acrylic acid, methacrylic acid, and fumaric acid is even more preferred. However, when used together with a polymerization inhibitor, a polycarboxylic acid-based 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, etc. are not bifunctional monomers but raw material monomers of the polyester resin.

[0066] The amount of the bifunctional monomer used is preferably 1 mol or more, more preferably 2 mol or more, based on 100 mol in total of the alcohol components of the polyester resin, from the viewpoint of enhancing the dispersibility between the styrene resin and the polyester resin and improving the dispersibility of the raw materials in the toner, and is preferably 30 mol or less, more preferably 20 mol or less, still more preferably 10 mol or less, from the viewpoint of improving the low-temperature fixability of the toner.

[0067] Specifically, it is preferable to produce the composite resin by the following method. When using the bifunctional monomer, the bifunctional monomer is preferably used together with the raw material monomers of the polyester resin from the viewpoint of improving the dispersibility of the pigment and the crystalline polyester resin in the toner.

[0068] (i) A method in which after the step (A) of polycondensation reaction with the raw material monomers of the polyester resin, the step (B) of addition polymerization reaction with the raw material monomers of the styrene resin is carried out In this method, step (A) is carried out under temperature conditions suitable for the polycondensation reaction, the 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. After step (B), the 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 are added to the polymerization system, and the polycondensation reaction in step (A) and the reaction with the bifunctional monomer can be further advanced.

[0069] (ii) A method in which after the step (B) of addition polymerization reaction with the raw material monomers of the styrene resin, the step (A) of polycondensation reaction with the raw material monomers of the polyester resin is carried out In this method, step (B) is carried out under temperature conditions suitable for the addition polymerization reaction, the temperature is raised, and the polycondensation reaction of step (A) is carried out under temperature conditions suitable for 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.

[0070] (iii) A method of performing a reaction under conditions where the polycondensation reaction step (A) of the raw material monomers of the polyester resin and the addition polymerization reaction step (B) of 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 temperature conditions suitable for the addition polymerization reaction, the temperature is raised, and under temperature conditions suitable for the polycondensation reaction, a raw material monomer of a polyester resin having a trivalent or higher valence serving as a crosslinking agent is added to the polymerization system as needed, and it is preferable to further carry out the polycondensation reaction of step (A). 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.

[0071] In the method of (i) above, instead of the step (A) of performing the polycondensation reaction, a previously polymerized polyester resin may be used. In the method of (iii) above, when performing the reaction under conditions where step (A) and step (B) proceed in parallel, a mixture containing the raw material monomers of the styrene resin can also be dropped into the mixture containing the raw material monomers of the polyester resin and reacted.

[0072] The methods of (i) to (iii) above are preferably carried out in the same container.

[0073] 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 calculations, the mass of the polyester resin is the amount obtained by subtracting the amount of the reaction water (calculated value) dehydrated by the polycondensation reaction from the mass of the raw material monomers of the polyester resin used, and the amounts of both reactive monomers are included in the amount of the raw material monomers of the polyester resin. Also, the amount of the styrene resin is the total amount of the raw material monomers of the styrene resin.

[0074] The softening point of the amorphous polyester resin is preferably 70°C or higher, more preferably 90°C or higher, still more preferably 100°C or higher from the viewpoint of charge stability, and preferably 170°C or lower, more preferably 160°C or lower, still more preferably 150°C or lower from the viewpoint of low-temperature fixability.

[0075] Note that the amorphous polyester resin may be composed of resins having different softening points from the viewpoints of low-temperature fixability and fixing width. The difference in the softening points of the two resins is preferably 10°C or more, more preferably 20°C or more, and preferably 60°C or less, more preferably 40°C or less.

[0076] The softening point of the amorphous polyester resin with the higher softening point (resin AH) is preferably 100°C or higher, more preferably 110°C or higher, still more preferably 120°C or higher from the viewpoint of fixing width, and preferably 170°C or lower, more preferably 160°C or lower, still more preferably 150°C or lower from the viewpoint of low-temperature fixability.

[0077] Also, from the viewpoint of charge stability, the softening point of the amorphous polyester resin (resin AL) with the lower softening point is preferably 70°C or higher, more preferably 90°C or higher, still more preferably 100°C or higher, and from the viewpoint of low-temperature fixability, it is preferably 130°C or lower, more preferably 125°C or lower, still more preferably 120°C or lower.

[0078] The mass ratio of resin AH to resin AL (resin AH / resin AL) is preferably 10 / 90 or higher, more preferably 20 / 80 or higher, still more preferably 30 / 70 or higher, and preferably 90 / 10 or lower, more preferably 80 / 20 or lower, still more preferably 75 / 25 or lower.

[0079] From the viewpoint of heat-resistant storage stability, the glass transition temperature of the amorphous polyester resin is preferably 40°C or higher, more preferably 50°C or higher, and from the viewpoint of low-temperature fixability, it is preferably 80°C or lower, more preferably 70°C or lower.

[0080] From the viewpoint of pigment dispersibility, the acid value of the amorphous polyester resin is preferably 5 mgKOH / g or higher, more preferably 10 mgKOH / g or higher, and from the viewpoint of charge stability, it is preferably 50 mgKOH / g or lower, more preferably 40 mgKOH / g or lower.

[0081] From the viewpoint of charge stability, the content of the amorphous polyester resin in the total amount of the crystalline polyester resin and the amorphous polyester resin is preferably 65% by mass or higher, more preferably 70% by mass or higher, still more preferably 75% by mass or higher, and preferably 95% by mass or lower, more preferably 90% by mass or lower, still more preferably 85% by mass or lower.

[0082] The mass ratio of the amorphous polyester resin to the crystalline polyester resin (amorphous polyester resin / crystalline polyester resin) is preferably 65 / 35 or more, more preferably 70 / 30 or more, still more preferably 75 / 25 or more, and preferably 95 / 5 or less, more preferably 90 / 10 or less, still more preferably 85 / 15 or less, from the viewpoints of low-temperature fixability and heat-resistant storage stability.

[0083] 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.

[0084] The total content of the crystalline polyester resin and the amorphous polyester resin 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.

[0085] 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, and preferably less than 100% by mass, more preferably 98% by mass or less, still more preferably 95% by mass or less in the toner.

[0086] The colorant contains an organic yellow pigment having a specific NH group amount from the viewpoint of the interaction with the crystalline polyester resin.

[0087] The NH group amount of the organic yellow pigment is 3.0 mmol / g or more, preferably 5.0 mmol / g or more, more preferably 7.0 mmol / g or more, still more preferably 10.0 mmol / g or more, and preferably 15.0 mmol / g or less, more preferably 13.0 mmol / g or less, still more preferably 12.5 mmol / g or less. Here, the NH group amount is the value obtained by dividing the total number of -NH- groups and -NH 2 groups in one molecule by the molecular weight.

[0088] As the organic yellow pigment, at least one selected from the group consisting of benzimidazolone pigments, isoindoline-based pigments, and condensed disazo pigments is preferred.

[0089] Examples of benzimidazolone pigments include C.I. Pigment Yellow 180 (total number of -NH- groups and -NH groups in one molecule = 6, molecular weight = 733, NH group amount = 8.2 mmol / g), etc. 2 Examples thereof include C.I. Pigment Yellow 180 (total number of -NH- groups and -NH groups in one molecule = 6, molecular weight = 733, NH group amount = 8.2 mmol / g), etc.

[0090] Examples of isoindoline-based pigments include C.I. Pigment Yellow 185 (total number of -NH- groups and -NH groups in one molecule = 4, molecular weight = 337, NH group amount = 11.9 mmol / g), etc. 2 Examples thereof include C.I. Pigment Yellow 185 (total number of -NH- groups and -NH groups in one molecule = 4, molecular weight = 337, NH group amount = 11.9 mmol / g), etc.

[0091] Examples of condensed disazo pigments include C.I. Pigment Yellow 93 (total number of -NH- groups and -NH groups in one molecule = 4, molecular weight = 937, NH group amount = 4.3 mmol / g), C.I. Pigment Yellow 95 (total number of -NH- groups and -NH groups in one molecule = 4, molecular weight = 917, NH group amount = 4.4 mmol / g), etc. 2 Examples thereof include C.I. Pigment Yellow 93 (total number of -NH- groups and -NH groups in one molecule = 4, molecular weight = 937, NH group amount = 4.3 mmol / g), C.I. Pigment Yellow 95 (total number of -NH- groups and -NH groups in one molecule = 4, molecular weight = 917, NH group amount = 4.4 mmol / g), etc. 2 Examples thereof include C.I. Pigment Yellow 93 (total number of -NH- groups and -NH groups in one molecule = 4, molecular weight = 937, NH group amount = 4.3 mmol / g), C.I. Pigment Yellow 95 (total number of -NH- groups and -NH groups in one molecule = 4, molecular weight = 917, NH group amount = 4.4 mmol / g), etc.

[0092] From the viewpoint of the heat storage stability of the toner, the organic yellow pigment used in the present invention is preferably at least one selected from benzimidazolone pigments and isoindoline-based pigments, more preferably at least one selected from C.I. Pigment Yellow 180 (PY180) and C.I. Pigment Yellow 185 (PY185), and even more preferably C.I. Pigment Yellow 185.

[0093] The content of the organic yellow pigment is preferably 1 part by mass or more, more preferably 3 parts by mass or more, even more preferably 5 parts by mass or more, and preferably 15 parts by mass or less, more preferably 12 parts by mass or less, even more preferably 10 parts by mass or less, based on 100 parts by mass of the binder resin.

[0094] Also, the mass ratio of the crystalline polyester resin to the organic yellow pigment (crystalline polyester resin / organic yellow pigment) is preferably 20 / 80 or more, more preferably 40 / 60 or more, still more preferably 50 / 50 or more, and preferably 90 / 10 or less, more preferably 85 / 15 or less, still more preferably 80 / 20 or less.

[0095] The colorant may contain other colorants as long as the effects of the present invention are not impaired. However, the content of the organic yellow pigment is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and still more preferably 100% by mass in the colorant. Examples of other colorants include carbon black, phthalocyanine blue, permanent brown FG, brilliant fast scarlet, pigment red 122, pigment green B, rhodamine-B base, solvent red 49, solvent red 146, solvent blue 35, quinacridone, carmine 6B, disazo yellow, and the like.

[0096] The content of the colorant is preferably 1 part by mass or more, more preferably 3 parts by mass or more, still more preferably 5 parts by mass or more, and preferably 15 parts by mass or less, more preferably 12 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.

[0097] The release agent contains paraffin wax. In the present invention, the paraffin wax refers to the paraffin wax defined in JIS K2235. The paraffin wax in the present invention may be either one made from petroleum (petroleum-based paraffin wax) or one made from coal (coal-based paraffin wax). For example, as the paraffin wax made from petroleum, paraffin wax obtained by refining petroleum such as highly purified paraffin wax obtained by further separating and purifying petroleum wax extracted from petroleum by vacuum distillation distillate oil to increase the ratio of linear hydrocarbons can be mentioned. On the other hand, as the paraffin wax made from coal, Fischer-Tropsch wax obtained by hydrogenating the distillation components by-produced during the production of synthetic petroleum by the Fischer-Tropsch method to remove unsaturated hydrocarbons and oxygen compounds can be mentioned. In the present invention, from the viewpoint of heat-resistant storage stability, paraffin wax obtained by refining petroleum is preferred.

[0098] From the viewpoints of heat-resistant storage stability and low-temperature fixing property, the melting point of the paraffin wax is preferably 60 °C or higher, more preferably 65 °C or higher, and preferably 110 °C or lower, more preferably 100 °C or lower.

[0099] The mass ratio of the crystalline polyester resin to the paraffin wax (crystalline polyester resin / paraffin wax) is preferably 10 / 90 or more, more preferably 30 / 70 or more, still more preferably 40 / 60 or more, and preferably 95 / 5 or less, more preferably 90 / 10 or less, still more preferably 85 / 15 or less.

[0100] The content of the paraffin wax is preferably 0.5 part by mass or more, more preferably 1 part by mass or more, still more preferably 1.5 part by mass or more, and preferably 15 parts by mass or less, more preferably 12 parts by mass or less, still more preferably 9 parts by mass or less with respect to 100 parts by mass of the binder resin.

[0101] The release agent may contain other release agents as long as the effects of the present invention are not impaired. However, the content of paraffin wax is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and even more preferably 100% by mass in the release agent. Examples of other release agents include polypropylene wax, polyethylene wax, ethylene-propylene copolymer wax; aliphatic hydrocarbon waxes such as microcrystalline wax and Fischer-Tropsch wax or their oxides; ester waxes such as carnauba wax, montan wax or their deacidified waxes, fatty acid ester waxes; fatty acid amides, fatty acids, higher alcohols, fatty acid metal salts, etc.

[0102] 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 part by mass or more, and preferably 15 parts by mass or less, more preferably 12 parts by mass or less, still more preferably 9 parts by mass or less with respect to 100 parts by mass of the binder resin.

[0103] In addition to the binder resin, colorant and release agent, the mixture to be melt-kneaded may contain additives such as charge control agents, magnetic powders, fluidity improvers, conductivity adjusters, reinforcing fillers such as fibrous substances, antioxidants, and cleaning property improvers.

[0104] 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.

[0105] 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.).

[0106] 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.

[0107] From the perspective 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 with respect to 100 parts by mass of the binder resin.

[0108] The mixture to be subjected to melt-kneading is preferably mixed in advance with a mixer such as a Henschel mixer or a ball mill and then supplied to an open-roll type kneader.

[0109] The open-roll type kneader refers to one in which the kneading part is not sealed but open, and the kneading heat generated during melt-kneading can be easily dissipated. The open-roll type kneader used in the present invention is provided with a raw material supply port and a kneaded product discharge port provided along the axial direction of the roll, and from the perspective of production efficiency, it is preferably a continuous open-roll type kneader.

[0110] The open-roll type kneader used in the present invention is preferably a kneader equipped with two rolls having different peripheral speeds, that is, two rolls of a roll with a high peripheral speed (high-speed rotating roll) and a roll with a low peripheral speed (low-speed rotating roll). In the present invention, from the perspective of the dispersibility of the kneaded product, it is preferable that the high-speed rotating roll functions as a heating roll and the low-speed rotating roll functions as a cooling roll, that is, it is preferable that the set temperature of the high-speed rotating roll is higher than the set temperature of the low-speed rotating roll. When the set temperatures of the rolls are different on the raw material input side and the kneaded product discharge side, it is preferable that at least on the raw material input side, the set temperature of the high-speed rotating roll is higher than the set temperature of the low-speed rotating roll, and it is more preferable that on both the raw material input side and the kneaded product discharge side, the set temperature of the high-speed rotating roll is higher than the set temperature of the low-speed rotating roll.

[0111] The temperature of the roll can be adjusted, for example, by the temperature of the heat medium passed through the inside of the roll, and for each roll, the inside of the roll may be divided into two or more parts and heat media with different temperatures may be passed through.

[0112] From the perspective of reducing the mechanical force during melt kneading and suppressing heat generation, the temperature on the raw material input side of the high-speed roll is preferably 80°C or higher, more preferably 100°C or higher, still more preferably 120°C or higher, and is preferably 160°C or lower, more preferably 150°C or lower. From the same perspective, the temperature on the raw material input side of the low-speed roll is preferably 25°C or higher, more preferably 40°C or higher, and is preferably 90°C or lower, more preferably 80°C or lower.

[0113] For both the high-speed roll and the low-speed roll, it is preferable that the temperature on the raw material input side is higher than that on the kneaded product discharge side. From the perspective of preventing the kneaded product from detaching from the roll and reducing the mechanical force and suppressing heat generation during melt kneading, the temperature difference between the raw material input side and the kneaded product discharge side is preferably 20°C or higher, more preferably 30°C or higher, and is preferably 60°C or lower, more preferably 50°C or lower.

[0114] The temperature on the raw material input side of the high-speed roll and the low-speed roll refers to the set temperature at the end of the raw material input side, and the temperature on the kneaded product discharge side refers to the set temperature at the end of the kneaded product discharge side, respectively.

[0115] From the perspective of reducing the mechanical force during kneading and suppressing heat generation, the peripheral speed of the high-speed roll is preferably 2 m / min or higher, more preferably 10 m / min or higher, still more preferably 25 m / min or higher, and is preferably 100 m / min or lower, more preferably 75 m / min or lower, still more preferably 50 m / min or lower. From the same perspective, the peripheral speed of the low-speed roll is preferably 1 m / min or higher, more preferably 5 m / min or higher, still more preferably 15 m / min or higher, and is preferably 90 m / min or lower, more preferably 60 m / min or lower, still more preferably 30 m / min or lower. Also, the ratio of the peripheral speeds of the two rolls (low-speed roll / high-speed roll) is preferably 1 / 10 or higher, more preferably 3 / 10 or higher, and is preferably 9.9 / 10 or lower, more preferably 8 / 10 or lower.

[0116] In addition, there are no particular limitations on the structure, size, material, etc. of each roll. The roll surface has grooves used for kneading, and examples of this shape include linear, spiral, corrugated, and uneven shapes.

[0117] After melt-kneading, it is preferable to appropriately cool the kneaded material until it reaches a hardness that can be pulverized, and then perform a pulverization and classification process to obtain toner particles. Here, cooling means cooling the kneaded material to 0°C or higher and 50°C or lower, or cooling it to below the glass transition temperature of the binder resin in the kneaded material.

[0118] In the pulverization of the kneaded material, the kneaded material may be pulverized at once to a desired particle size or pulverized step by step. However, from the viewpoint of efficient and more uniform pulverization, it is preferable to perform it in two stages: coarse pulverization and fine pulverization.

[0119] Examples of the pulverizer used for coarse pulverization include hammer mills, cutter mills, atomizers, rotorplexes, etc.

[0120] In coarse pulverization, the kneaded material is appropriately coarsely pulverized until the particle size becomes about 0.1 to 3 mm, and then passed through a sieve with an aperture of about 2 to 3 mm. It is preferable that the pulverized material passing through the sieve is used for fine pulverization as a pulverized material with a maximum diameter of 2 to 3 mm or less.

[0121] Examples of the pulverizer used for fine pulverization include jet mills such as fluidized bed jet mills and impact plate jet mills, and mechanical mills.

[0122] The degree of fine pulverization is preferably adjusted as appropriate according to the particle size of the target toner particles.

[0123] Examples of the classifier used for classification include air classifiers, inertial classifiers, sieve classifiers, etc. During the classification process, the pulverized material that was not sufficiently pulverized and removed may be returned to the pulverization process, and the pulverization process and the classification process may be repeated as necessary.

[0124] In the present invention, from the viewpoint of improving transferability, it is preferable to perform a step of mixing the obtained toner particles with an external additive.

[0125] Examples of the external additive used in the external addition step 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 these may be used in combination. Among these, silica is preferable, and from the viewpoint of the transferability of the toner, hydrophobic silica that has been hydrophobically treated is more preferable.

[0126] 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.

[0127] 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 even more preferably 90 nm or less.

[0128] The mixing of the toner particles and the external additive can be performed according to a conventional method, and a mixer such as a Henschel mixer can be used.

[0129] From the viewpoints of the chargeability, fluidity, and transferability of the toner, the content of the external additive is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, and even more preferably 0.3 parts by mass or more with respect to 100 parts by mass of the toner particles before being treated with the external additive, and preferably 5 parts by mass or less, more preferably 3 parts by mass or less.

[0130] The volume median particle diameter (D 50) is preferably 3 μm or more, more preferably 4 μm or more, and preferably 15 μm or less, more preferably 10 μm or less. In the present specification, the volume median particle diameter (D 50 ) means the particle diameter at which the cumulative volume frequency calculated by the volume fraction becomes 50% when calculated from the smaller particle diameter. When the toner is treated with an external additive, the volume median particle diameter of the toner particles before being treated with the external additive is defined as the volume median particle diameter of the toner.

[0131] The toner obtained by the method 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, in an image forming apparatus using a one-component development system or a two-component development system, respectively.

Examples

[0132] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited by these examples. Physical properties such as those of the resin were measured by the following methods.

[0133] 〔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 defined as the softening point.

[0134] 〔Maximum peak temperature of endotherm of resin〕 Using a differential scanning calorimeter "Q-100" (manufactured by TA Instruments Japan Co., Ltd.), 0.01 to 0.02 g of the sample is weighed into an aluminum pan, cooled from room temperature (25 °C) to 0 °C at a cooling rate of 10 °C / min, and maintained at 0 °C for 1 minute. Then, it is measured 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 peak temperature of the endotherm. In the case of a crystalline resin, the maximum peak temperature of the endotherm is defined as the melting point.

[0135] 〔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 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 peak temperature of the endotherm and the tangent line showing the maximum slope from the rising part of the peak to the apex of the peak is defined as the glass transition temperature.

[0136] 〔Acid value of resin〕 Measure based on the method of JIS K 0070:1992. However, only for the measurement solvent, change from the mixed solvent of ethanol and ether 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, respectively.

[0137] 〔Melting point of release agent〕 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 at a heating rate of 10 °C / min, and then cool it from that temperature to 0 °C at a cooling rate of 10 °C / min. Next, heat the sample at a heating rate of 10 °C / min up to 200 °C for measurement, and define the maximum peak temperature of the endotherm as the melting point.

[0138] 〔Average particle diameter of external additive〕 The average particle diameter refers to the number average particle diameter. Measure the particle diameters (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.

[0139] 〔Volume median diameter (D 50 ) of toner〕 · Measuring instrument: “Coulter Multisizer (registered trademark) III” (manufactured by Beckman Coulter, Inc.) · Aperture diameter: 100 μm · Analysis software: "Multi-Sizer (registered trademark) III version 3.51" (manufactured by Beckman Coulter, Inc.) · Electrolyte: "Isoton (registered trademark) II" (manufactured by Beckman Coulter, Inc.) · Dispersion liquid: Prepared by dissolving polyoxyethylene lauryl ether "Emulgen (registered trademark) 109P" [manufactured by Kao Corporation, HLB (Griffin) = 13.6] in the electrolyte to adjust to 5% by mass · Dispersion conditions: Add 10 mg of the measurement sample to 5 mL of the dispersion liquid, disperse it with an ultrasonic disperser (machine name: US-1 manufactured by SND Co., Ltd., output: 80 W) for 1 minute, then add 25 mL of the electrolyte, and further disperse it with the ultrasonic disperser for 1 minute to prepare a sample dispersion liquid. · Measurement conditions: After adjusting the concentration of the sample dispersion liquid added to 100 mL of the electrolyte to a concentration at which the particle size of 30,000 particles can be measured in 20 seconds, measure 30,000 particles, and determine the volume median diameter (D 50 ) from its particle size distribution.

[0140] Resin production example 1 Put the alcohol component, fumaric acid, esterification catalyst, and polymerization inhibitor shown in Table 1 into a 10-liter four-necked flask equipped with a nitrogen introduction tube, a dehydrating tube, a stirrer, and a thermocouple, heat it to 230°C in a mantle heater under a nitrogen atmosphere, and perform polycondensation for 7 hours. Then, cool it down to 200°C, add trimellitic anhydride, then heat it to 210°C, and perform a polycondensation reaction to obtain an amorphous polyester resin (resin A1). The physical properties of the obtained resin are shown in Table 1.

[0141]

Table 1

[0142] Resin production example 2 The raw material monomers, both reactive monomers, and esterification catalysts of the polyester resin other than trimellitic anhydride shown in Table 2 were placed in a 10-liter four-necked flask equipped with a dehydration tube equipped with a nitrogen introduction tube, a stirrer, and a thermocouple, and heated to 160 °C in a mantle heater under a nitrogen atmosphere. Then, a mixture of the raw material monomers of the styrene resin and a polymerization initiator was added dropwise over 1 hour to carry out polymerization. Then, the temperature was raised to 200 °C and aged for 1 hour to produce a styrene resin in the reaction system. Then, the temperature was raised to 230 °C over 1 hour, and after confirming that all the solid monomers had melted and reacted, the pressure was reduced to 8 kPa and dehydration condensation was carried out for 1 hour. Then, the temperature was lowered to 210 °C, trimellitic anhydride was added, and after reacting for another 1 hour, the pressure was reduced to 8 kPa, and the reaction was carried out until the softening point shown in Table 2 was reached to obtain an amorphous composite resin (Resin A2). The physical properties of the obtained resin are shown in Table 2.

[0143]

Table 2

[0144] Resin Production Example 3 The alcohol component, carboxylic acid component, and esterification catalyst shown in Tables 3 and 4 were placed in a 10-liter four-necked flask equipped with a dehydration tube equipped with a nitrogen introduction tube, a stirrer, and a thermocouple, and heated in a mantle heater under a nitrogen atmosphere to 200 °C over 8 hours. Then, the reaction was carried out at 8 kPa until the softening point shown in Tables 3 and 4 was reached to obtain crystalline polyester resins (Resins C1 to C4, C6, C7, C9). The physical properties of the obtained resins are shown in Tables 3 and 4.

[0145] Resin Production Example 4 The alcohol component, carboxylic acid component, esterification catalyst, and polymerization inhibitor shown in Tables 3 and 4 were placed in a 10-liter four-necked flask equipped with a dehydration tube equipped with a nitrogen introduction tube, a stirrer, and a thermocouple, and heated in a mantle heater under a nitrogen atmosphere to 200 °C over 8 hours. Then, the reaction was carried out at 8 kPa until the softening point shown in Tables 3 and 4 was reached to obtain crystalline polyester resins (Resins C5, C8). The physical properties of the obtained resins are shown in Tables 3 and 4.

[0146]

Table 3

[0147]

Table 4

[0148] Examples 1 to 8 and Comparative Examples 1 to 3 40 parts by mass of Resin A1, 40 parts by mass of Resin A2, 20 parts by mass of the crystalline polyester resin shown in Table 5, the colorant shown in Table 5, 4 parts by mass of the mold release agent "HNP-9" (manufactured by Nippon Seiro Co., Ltd., paraffin wax, melting point: 80°C), and 0.5 parts by mass of the charge control agent "Bontron E-304" (manufactured by Orient Chemical Industries, Ltd.) were thoroughly mixed with a Henschel mixer and then melt-kneaded under the conditions shown below.

[0149] A continuous open-roll type twin-screw kneader "Neidex" (manufactured by Mitsui Mining Co., Ltd., roll outer diameter: 14 cm, effective roll length: 80 cm) was used. The operating conditions of the continuous open-roll type twin-screw kneader were a peripheral speed of the high-speed roll (front roll) of 32.4 m / min, a peripheral speed of the low-speed roll (back roll) of 21.7 m / min, and a roll gap of 0.1 mm. The temperature of the heating medium and the cooling medium inside the roll were 145°C on the raw material input side and 100°C on the kneaded product discharge side of the high-speed roll, and 75°C on the raw material input side and 35°C on the kneaded product discharge side of the low-speed roll. Also, the supply rate of the raw material mixture was 10 kg / h, and the average residence time was about 3 minutes.

[0150] The obtained kneaded product was cooled and roughly pulverized by a pulverizer "Rotoplex" (manufactured by Hosokawa Micron Corporation) to obtain a roughly pulverized product with a maximum diameter of 2 mm or less using a sieve with an opening of 2 mm. The obtained roughly pulverized product was finely pulverized by adjusting the pulverization pressure so that the volume median diameter (D 50 ) became 5.5 μm using an air classifier "DS2 type" (impact plate type, manufactured by Nippon Pneumatic Mfg. Co., Ltd.). The obtained finely pulverized product was classified using an air classifier "DSX2 type" (manufactured by Nippon Pneumatic Mfg. Co., Ltd.) so that the volume median diameter (D50 ) The classification was carried out by adjusting the static pressure (internal pressure) so that

[0151] To 100 parts by mass of the obtained toner particles, 1.0 part by mass of "R972" (hydrophobic silica, manufactured by Nippon Aerosil Co., Ltd., hydrophobizing agent: DMDS, average particle diameter: 16 nm) and 1.0 part by mass of "RX50" (hydrophobic silica, manufactured by Nippon Aerosil Co., Ltd., hydrophobizing agent: HMDS, average particle diameter: 40 nm) were added as external additives, and the mixture was mixed with a Henschel mixer at 3700 r / min for 3 minutes to perform external additive treatment, thereby obtaining toner.

[0152] Comparative Example 4 In the melt-kneading step, a toner was obtained in the same manner as in Example 3 except that 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 of the twin-screw extruder 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.

[0153] Comparative Example 5 A crystalline polyester resin and a colorant were preliminarily melt-kneaded using a continuous open-roll type twin-screw kneader "Neodeck" (manufactured by Mitsui Mining Co., Ltd., roll outer diameter: 14 cm, effective roll length: 80 cm) (the melt-kneading conditions were the same as above) to prepare a pigment masterbatch. Then, a toner was obtained in the same manner as in Comparative Example 4 except that the pigment masterbatch was used instead of the crystalline resin and the colorant.

[0154] Comparative Example 6 A toner was obtained in the same manner as in Example 3 except that 4 parts by mass of carnauba wax (manufactured by Kato Yoko Co., Ltd., carnauba wax No. 1, melting point: 88°C) was used instead of paraffin wax as the release agent.

[0155] The colorants used in the examples are as follows. C.I. Pigment Yellow 180: "TONER YELLOW HG" (manufactured by Hoechst Color Japan Co., Ltd.) C.I. Pigment Yellow 185: "Pariole Yellow D1155" (manufactured by DIC Corporation (BASF Color & Effect Japan Co., Ltd.)) C.I. Pigment Yellow 155: "TONER YELLOW 3GP-CT" (manufactured by Hoechst Color Japan Co., Ltd.)

[0156] Test Example [Heat Resistance and Storage Stability] 5 g of toner was placed in a 20 mL polypropylene container. The container with the toner was placed in a thermo-hygrostat at 48°C and 60% relative humidity and stored for 120 hours with the lid of the container open. The degree of aggregation of the toner after storage was measured by the following method and used as an index of heat resistance and storage stability. The results are shown in Table 5. The smaller this value, the better the heat resistance and storage stability.

[0157] (Degree of Aggregation) The degree of aggregation is measured using a powder tester (manufactured by Hosokawa Micron Corporation). Sieves with mesh openings of 150 μm, 75 μm, and 45 μm are stacked, 5 g of toner is placed on top, and it is vibrated for 60 seconds with a vibration amplitude of 1 mm. After vibration, the amount of toner remaining on the sieve is measured, and the degree of aggregation is calculated using the following formula.

[0158]

Equation

[0159]

Table 5

[0160] From the above results, it can be seen that the toners of Examples 1 to 8 have good heat resistance and storage stability compared with Comparative Examples 1 to 6. The decrease in heat resistance and storage stability in Comparative Example 5 is considered to be due to insufficient refinement of the wax domain and the lack of promotion of crystallization of the crystalline polyester resin because no wax (release agent) was added at this time even though the crystalline polyester resin and the colorant were pre-kneaded in a continuous open roll type twin-screw kneader.

Industrial Applicability

[0161] The electrostatic charge image developing toner obtained by the method of the present invention is suitably used for developing a latent image formed in an electrostatic charge image developing method, an electrostatographic method, an electrophotographic method, or the like.

Claims

1. A method for manufacturing an electrostatic charge image developing toner having a step of melt-kneading a mixture containing a binder resin, a colorant, and a release agent, wherein the binder resin contains a crystalline polyester resin having an ester group concentration of 5.0 mmol / g or more and 10.0 mmol / g or less, and the colorant has a total number of —NH— groups and —NH ２ groups in one molecule, and when the value obtained by dividing the total number by the molecular weight is defined as the amount of NH groups, contains an organic yellow pigment having an NH group amount of 3.0 mmol / g or more, the release agent contains paraffin wax, and the melt-kneading of the mixture is performed using an open roll kneader. A method for manufacturing an electrostatic charge image developing toner.

2. The method for producing a toner for electrostatic charge image development according to claim 1, wherein the content of the crystalline polyester resin is 5% by mass or more and 35% by mass or less in the binder resin.

3. The method for producing a toner for electrostatic charge image development according to claim 1 or 2, wherein the mass ratio of the crystalline polyester resin to the paraffin wax is 10 / 90 or more and 95 / 5 or less.

4. The method for producing a toner for electrostatic charge image development according to any one of claims 1 to 3, wherein the mass ratio of the crystalline polyester resin to the organic yellow pigment is 20 / 80 or more and 90 / 10 or less.

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