Method for producing toner for electrostatic charge image development

Abstract

To provide a method for manufacturing electrostatic charge image development toner excellent in low temperature fixability and durability.SOLUTION: A method for manufacturing electrostatic charge image development toner comprises the step of melting and mixing the mixture of a raw material including an amorphous resin, a crystalline polyester resin and a release agent by a twin screw extruder. In one or more material supply ports included at each of a position f1 having less than 0.3 L from the entrance side end of a barrel and a position f2 having 0.3 L or more and 0.9 L or less when setting the length of the barrel of the twin screw extruder to L. A raw material including the amorphous resin is supplied from a material supply port F1 at the position f1, and a raw material including the crystalline polyester resin and the release agent is supplied from a material supply port F2 at the second position f2.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 recent years, with the increasing speed, miniaturization, and high image quality of printers and copiers, there has been a need for toners that can meet these demands.

[0003] Conventionally, various studies have been made on toner manufacturing methods in order to design arbitrary toners. For example, in Patent Document 1, in a method of manufacturing a toner by melt-kneading a composition composed of a resin and an additive, cooling, solidifying, pulverizing, and classifying, the additive concentration in the resin (hereinafter referred to as the front-half additive concentration) is 10 to 50% by weight from at least one raw material supply port provided at a position within 0.3L from the inlet side of a kneading extruder having an extrusion flowability and a barrel length L. A mixed raw material is continuously supplied, and from one to five raw material supply ports provided at positions from 0.3L to 0.9L from the inlet side, a raw material of resin alone or having an additive concentration in the resin of 20% by weight or less and lower than the above front-half additive concentration is continuously supplied. And the ratio of the supply flow rates of the raw material supplied to the raw material supply port at a position within 0.3L and the raw material supplied to the raw material supply port at a position from 0.3L to 0.9L is set to 10:1 to 1:5 (weight ratio), and the kneaded product is continuously taken out from the outlet of the kneading extruder. It is described that a toner excellent in dispersibility of the additive in the resin, with less molecular cleavage of the resin, and excellent quality can be obtained by the continuous manufacturing method of the toner.

[0004] Also, Patent Document 2 describes a method for manufacturing an electrostatic charge image developing toner in which at least a resin and a colorant are blended and mixed, then kneaded, and then pulverized and classified to obtain a toner. In this method, toner fine powder is supplied during the kneading process. By this method, even a large amount of toner fine powder can be recycled into the manufacturing process with good productivity, the performance deterioration of the toner with recycled fine powder is small, the fixing performance is good, and the image and image quality characteristics are stable even during continuous use, and a toner with excellent durability can be obtained.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, the toners described in Patent Documents 1 and 2 do not yet have sufficient low-temperature fixability and durability, and there is room for improvement.

[0007] The present invention relates to a method for manufacturing an electrostatic charge image developing toner excellent in low-temperature fixability and durability.

Means for Solving the Problems

[0008] The present invention relates to a method for producing an electrostatic charge image developing toner including a step of melt-kneading a mixture of raw materials containing an amorphous resin, a crystalline polyester resin, and a release agent using a twin-screw extruder. When the length of the barrel of the twin-screw extruder is L, at least one raw material supply port is provided at a position f1 less than 0.3L from the inlet side end of the barrel and at a position f2 of 0.3L or more and 0.9L or less, respectively. A raw material containing an amorphous resin is supplied from the raw material supply port F1 at f1, and a raw material containing a crystalline polyester resin and a release agent is supplied from the raw material supply port F2 at f2.

Effect of the Invention

[0009] By the method of the present invention, an electrostatic charge image developing toner excellent in low-temperature fixability and durability can be obtained.

Embodiments for Carrying Out the Invention

[0010] The present invention is a method for producing an electrostatic charge image developing toner including a step of melt-kneading a mixture of raw materials containing an amorphous resin, a crystalline polyester resin, and a release agent using a twin-screw extruder. When melt-kneading the mixture of raw materials using a twin-screw extruder, the amorphous resin, the crystalline polyester resin, and the release agent are each supplied to the twin-screw extruder from a predetermined position, whereby an electrostatic charge image developing toner (hereinafter also simply referred to as toner) excellent in low-temperature fixability and durability is obtained. The present invention has been completed upon finding this.

[0011] Although the details of the reason why the effect of the present invention is achieved are unclear, it is presumed to be due to the following mechanism. Although the crystalline polyester resin is excellent in low-temperature fixability, when melt-kneaded using a twin-screw extruder excellent in productivity and versatility, it separates from the amorphous binder resin which is the main component of the toner and easily forms coarse domains together with the release agent. As the addition amount is increased, there is a problem that the durability in a high-temperature and high-humidity environment tends to decrease. For example, in Patent Document 1, in the melt-kneading process of a kneading extruder, in order to improve the dispersion state and maintain an appropriate dispersion diameter by kneading an object to be dispersed such as a pigment for a long time, and also to perform short-time kneading to avoid molecular cleavage of the resin, it is known to divide the raw material supply port. However, as a result of the study by the present inventors, it has become clear that this is not the case in the dispersion of crystalline polyester resins. In the melt-kneading process of a twin-screw extruder, the raw material mixture is heated by being rubbed against the barrel, and the melt-kneading proceeds. However, when a crystalline polyester resin is added in addition to the mold release agent, the mold release agent and the crystalline polyester resin melt and have a lower viscosity in the barrel prior to the amorphous binder resin, so that the friction with the barrel required for the main component, the amorphous binder resin, to melt becomes insufficient. As a result, it is necessary to disperse the crystalline polyester resin and the mold release agent in a state where the main component, the amorphous binder resin serving as the dispersion medium, remains insufficiently melted, and an attempt is made to disperse the crystalline polyester resin and the mold release agent at a higher concentration than designed. As a result, sufficient kneading strength is not imparted, and coarse domains of the crystalline polyester resin and the mold release agent are formed. On the other hand, in the present invention, a raw material containing an amorphous resin is supplied from a raw material supply port F1 close to the inlet-side end of the barrel of the twin-screw extruder, and a raw material containing a crystalline polyester resin and a mold release agent is supplied from a raw material supply port F2 farther from the inlet-side end of the barrel than the raw material supply port F1, and melt-kneading is performed, whereby sufficient friction between the amorphous binder resin and the barrel can be ensured. Thereby, the amorphous binder resin serving as the dispersion medium can be sufficiently melted, a good dispersion state of the crystalline polyester resin and the mold release agent can be achieved, and a toner capable of achieving both low-temperature fixability and durability in a high-temperature and high-humidity environment can be obtained.

[0012] Examples of the amorphous resin include amorphous polyester resins, vinyl resins such as styrene resins, epoxy resins, polycarbonate resins, polyurethane resins, and composite resins containing two or more of these resins. Among these, polyester resins are preferred from the viewpoint of low-temperature fixability. Examples of the polyester resin include polyester resins and composite resins containing a polyester resin and a styrene resin.

[0013] Note that 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]. A crystalline resin has a crystallinity index of 0.6 or more, preferably 0.7 or more, more preferably 0.9 or more, and is a resin of 1.4 or less, preferably 1.2 or less, more preferably 1.1 or less. On the other hand, an amorphous resin is a resin in which no endothermic peak is observed, or if an endothermic peak is observed, the crystallinity index exceeds 1.4, preferably exceeds 1.5, more preferably is 1.6 or more, or is a resin of less than 0.6, preferably 0.5 or less. The crystallinity of the resin can be adjusted by the type and ratio of the raw material monomers, and manufacturing conditions (e.g., reaction temperature, reaction time, cooling rate), etc. Note that the maximum peak temperature of endotherm refers to the temperature of the peak with the largest peak area among the observed endothermic peaks. In a crystalline resin, the maximum peak temperature of endotherm is taken as the melting point.

[0014] 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.

[0015] Examples of the alkylene oxide adduct of bisphenol A include the formula (I):

[0016]

Chemical formula

[0017] (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, and even more preferably 4 or less.) The compound represented by is preferred.

[0018] 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, even more preferably 90 mol% or more, even more preferably 95 mol% or more, and even more preferably 100 mol%.

[0019] Examples of other alcohol components include aliphatic diols, bisphenol A, hydrogenated bisphenol A, sorbitol, pentaerythritol, glycerin, and polyhydric alcohols such as trimethylolpropane with 3 or more valences.

[0020] Examples of the carboxylic acid component include aliphatic dicarboxylic acid compounds, aromatic dicarboxylic acid compounds, and polyhydric carboxylic acid compounds with 3 or more valences.

[0021] 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 with 1 to 3 carbon atoms.

[0022] Examples of the aromatic dicarboxylic acid compounds include phthalic acid, isophthalic acid, terephthalic acid, anhydrides of these acids, and alkyl esters of these acids with 1 to 3 carbon atoms.

[0023] Examples of the polyhydric carboxylic acid compounds with 3 or more valences include trimellitic acid, pyromellitic acid, anhydrides of these acids, and alkyl esters of these acids with 1 to 3 carbon atoms.

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

[0025] The equivalent ratio (COOH group / OH group) of the carboxylic acid component to the alcohol component is preferably 0.6 or more, more preferably 0.7 or more, still more preferably 0.75 or more, and preferably 1.2 or less, more preferably 1.16 or less, from the viewpoint of adjusting the softening point of the polyester resin.

[0026] The amorphous 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 an esterification cocatalyst, a polymerization inhibitor, etc., preferably at a temperature of 160°C or higher, more preferably 200°C or higher, and preferably 250°C or lower, more preferably 240°C or lower.

[0027] Examples of the esterification catalyst include tin compounds such as dibutyltin oxide and tin(II) 2-ethylhexanoate, and titanium compounds such as titanium diisopropylate bistriethanolamineate. 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 esterification cocatalyst include gallic acid. The amount of the esterification 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 t-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.

[0028] 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.

[0029] In the amorphous composite resin having the polyester resin and the styrene resin, the polyester 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").

[0030] 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.

[0031] In addition, the styrenic 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 this specification, “(iso)” means including both the case where this group is present and the case where it is not present, and when these groups are not present, it indicates normal. Further, “(meth)acrylic acid” means acrylic acid, methacrylic acid, or both of them.

[0032] 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 styrenic resin is preferably 7 or more, more preferably 8 or more, and preferably 12 or less, more preferably 10 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.

[0033] The raw material monomers of the styrenic 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.

[0034] 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, etc., a polymerization inhibitor, 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.

[0035] 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.

[0036] The amorphous composite resin is preferably a resin in which a polyester resin and a styrene resin are bonded, and more preferably a resin 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.

[0037] 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 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-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. is not a bifunctional monomer but a raw material monomer of the polyester resin.

[0038] The amount of the bifunctional monomer used is preferably 1 mol or more, more preferably 2 mol or more, per 100 mol of the total alcohol components of the polyester resin, from the viewpoint of charge stability under high temperature and high humidity, and is preferably 30 mol or less, more preferably 20 mol or less, still more preferably 10 mol or less, from the viewpoint of enhancing the dispersibility between the styrene resin and the polyester resin and improving the transferability of the toner. Also, the amount of the bifunctional monomer used is preferably 1 part by mass or more, more preferably 2 parts by mass or more, per 100 parts by mass of the total raw material monomers of the styrene resin, from the viewpoint of charge stability under high temperature and high humidity, and is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, still more preferably 10 parts by mass or less, from the viewpoint of enhancing the dispersibility between the styrene resin and the polyester resin and improving the transferability of the toner. Here, the polymerization initiator is included in the total of the raw material monomers of the styrene resin.

[0039] The amorphous composite resin can be produced, for example, by a method including a step (A) of polycondensation reaction using the raw material monomers of the polyester resin and a step (B) of addition polymerization reaction using the raw material monomers of the styrene resin. (i) Step (B) may be carried out after step (A), (ii) Step (A) may be carried out after step (B), or (iii) Steps (A) and (B) may be carried out simultaneously. Note that the bifunctional monomer is preferably used together with the raw material monomers of the styrene resin.

[0040] In the method of (i), after step (B), the reaction temperature may be raised again, and if necessary, raw material monomers of a trivalent or higher amorphous polyester resin that serves as a crosslinking agent and the like may be added to the reaction system to further proceed with the polycondensation reaction in step (A) and the reaction with the bifunctional monomer. Also, instead of the step (A) of carrying out the polycondensation reaction, a pre-polymerized polycondensation resin may be used. When steps (A) and (B) proceed in parallel, a mixture containing the raw material monomers of the styrene resin may be dropped into a mixture containing the raw material monomers of the polyester resin for reaction.

[0041] Step (A) and step (B) are preferably carried out in the same container.

[0042] The mass ratio of the polyester resin to the styrene resin in the amorphous 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 charge stability under high temperature and high humidity, and is 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 excluding the amount of 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.

[0043] The softening point of the amorphous resin is preferably 90°C or higher, more preferably 100°C or higher, from the viewpoint of storage stability, and is preferably 160°C or lower, more preferably 140°C or lower, from the viewpoint of low-temperature fixability.

[0044] Note that the amorphous 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 higher, more preferably 20°C or higher, still more preferably 30°C or higher, and is preferably 60°C or lower, more preferably 50°C or lower.

[0045] The softening point of the amorphous resin with a higher softening point (resin AH) is preferably 110°C or higher, more preferably 120°C or higher, still more preferably 140°C or higher, from the viewpoint of fixing width, and is preferably 180°C or lower, more preferably 160°C or lower, from the viewpoint of low-temperature fixability.

[0046] Also, from the perspective of storage stability, the softening point of the amorphous 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 perspective of low-temperature fixing property, it is preferably 130°C or lower, more preferably 125°C or lower, still more preferably 120°C or lower.

[0047] 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 70 / 30 or lower.

[0048] From the perspective of storage stability, the glass transition temperature of the amorphous resin is preferably 40°C or higher, more preferably 50°C or higher, and from the perspective of low-temperature fixing property, it is preferably 80°C or lower, more preferably 70°C or lower, still more preferably 65°C or lower.

[0049] From the perspective of low-temperature fixing property, the acid value of the amorphous resin is preferably 1 mgKOH / g or higher, more preferably 3 mgKOH / g or higher, and from the perspective of hygroscopicity, it is preferably 20 mgKOH / g or lower, more preferably 15 mgKOH / g or lower.

[0050] From the perspective of transfer efficiency, the content of the amorphous resin in the total amount of the amorphous resin and the crystalline polyester resin is preferably 55% by mass or higher, more preferably 60% by mass or higher, still more preferably 70% by mass or higher, still more preferably 80% by mass or higher, and from the perspective of low-temperature fixing property, it is preferably 99% by mass or lower, more preferably 97% by mass or lower, still more preferably 96% by mass or lower.

[0051] Examples of the crystalline polyester resin include crystalline polyester resins and crystalline composite resins having a polyester resin and a styrene resin.

[0052] As the crystalline polyester resin, for example, a polycondensate of an alcohol component containing an aliphatic diol and a carboxylic acid component containing an aliphatic dicarboxylic acid compound is preferable.

[0053] Examples of the aliphatic diol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, neopentyl glycol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, etc. One kind may be used alone, or two or more kinds may be used in combination.

[0054] From the viewpoint of low-temperature fixing property, the aliphatic diol is preferably an α,ω-aliphatic diol having a hydroxyl group at the terminal of the carbon chain, and more preferably an α,ω-straight-chain alkanediol.

[0055] From the viewpoint of the dispersibility of the colorant, the number of carbon atoms of the aliphatic diol is preferably 6 or more, more preferably 10 or more, and from the viewpoint of storage stability, it is preferably 14 or less, more preferably 12 or less.

[0056] The content of the aliphatic diol in the alcohol component is preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, and still more preferably 95 mol% or more.

[0057] Examples of other alcohol components include aromatic diols such as alkylene oxide adducts of bisphenol A, and polyhydric alcohols having three or more valences such as sorbitol, pentaerythritol, glycerin, and trimethylolpropane.

[0058] Examples of the aliphatic dicarboxylic acid compounds include succinic acid (number of carbon atoms: 4), fumaric acid (number of carbon atoms: 4), adipic acid (number of carbon atoms: 6), suberic acid (number of carbon atoms: 8), azelaic acid (number of carbon atoms: 9), sebacic acid (number of carbon atoms: 10), dodecanedioic acid (number of carbon atoms: 12), tetradecanedioic acid (number of carbon atoms: 14), succinic acid having an alkyl group or alkenyl group in the side chain, anhydrides of these acids, alkyl esters of these acids having 1 to 3 carbon atoms, and the like.

[0059] From the viewpoint of low-temperature fixability, the number of carbon atoms of the aliphatic dicarboxylic acid compound is preferably 4 or more, more preferably 8 or more, and from the viewpoint of storage stability, it is preferably 14 or less, more preferably 12 or less.

[0060] The content of the aliphatic dicarboxylic acid compound is preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, and still more preferably 95 mol% or more in the carboxylic acid component.

[0061] Examples of the other carboxylic acid components include aromatic dicarboxylic acid compounds, aliphatic dicarboxylic acid compounds, and carboxylic acid compounds having a trivalent or higher valence.

[0062] The alcohol component may appropriately contain a monohydric alcohol, and the carboxylic acid component may appropriately contain a monohydric carboxylic acid compound.

[0063] From the viewpoint of storage stability, the equivalent ratio (COOH group / OH group) of the carboxylic acid component to the alcohol component is preferably 0.8 or more, more preferably 0.9 or more, and from the viewpoint of low-temperature fixability, it is preferably 1.2 or less, more preferably 1.1 or less.

[0064] The polycondensation reaction conditions of the alcohol component and the carboxylic acid component of the crystalline polyester resin are the same as those of the amorphous polyester resin except that the suitable reaction temperatures are different. The reaction temperature is preferably 120°C or higher, more preferably 180°C or higher, and preferably 230°C or lower, more preferably 220°C or lower.

[0065] In the crystalline composite resin having the polyester resin and the styrene resin, the polyester resin is the same as the crystalline 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").

[0066] From the viewpoint of storage stability, the content of the styrene compound, preferably styrene, in the raw material monomer of the styrene resin 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.

[0067] The raw material monomer of the styrene resin may contain raw material monomers other than the styrene compound, for example, (meth)acrylic acid alkyl esters, 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, etc.

[0068] The addition polymerization reaction of the raw material monomer 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 or dicumyl peroxide, a polymerization inhibitor, 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.

[0069] 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 monomer of the styrene resin.

[0070] The crystalline composite resin is preferably a resin in which a polyester resin and a styrene-based resin are combined, and more preferably a resin chemically bonded through a bifunctional monomer capable of reacting with any of the raw material monomers of the polyester resin and the raw material monomers of the styrene-based resin.

[0071] The method for producing the bifunctional monomer and the crystalline composite resin is the same as that of the composite resin described as the amorphous resin.

[0072] The mass ratio of the polyester resin to the styrene-based resin (polyester resin / styrene-based resin) in the crystalline composite resin is preferably 98 / 2 or less, more preferably 95 / 5 or less, still more preferably 90 / 10 or less from the viewpoint of charge stability under high temperature and high humidity, 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 removing the amount of reaction water (calculated value) dehydrated by the polycondensation reaction from the mass of the raw material monomers of the polyester resin used, and the amount of the bifunctional monomer is included in the amount of the raw material monomers of the polyester resin. The amount of the styrene-based resin is the total amount of the raw material monomers of the styrene-based resin.

[0073] The softening point of the crystalline polyester-based resin is preferably 50°C or higher, more preferably 65°C or higher, still more preferably 70°C or higher from the viewpoint of storage stability, and preferably 120°C or lower, more preferably 110°C or lower from the viewpoint of low-temperature fixability.

[0074] The melting point of the crystalline polyester-based resin is preferably 60°C or higher, more preferably 70°C or higher from the viewpoint of storage stability, and preferably 130°C or lower, more preferably 120°C or lower from the viewpoint of low-temperature fixability.

[0075] The content of the crystalline polyester resin is preferably 1% by mass or more, more preferably 3% by mass or more, still more preferably 4% by mass or more, from the viewpoint of low-temperature fixability, in the total amount of the amorphous resin and the crystalline polyester resin, and preferably 45% by mass or less, more preferably 40% by mass or less, still more preferably 30% by mass or less, still more preferably 20% by mass or less, from the viewpoint of transfer efficiency.

[0076] The mass ratio of the amorphous resin to the crystalline polyester resin (amorphous resin / crystalline polyester resin) is preferably 60 / 40 or more, more preferably 65 / 35 or more, still more preferably 70 / 30 or more, from the viewpoint of low-temperature fixability, and preferably 99 / 1 or less, more preferably 97 / 3 or less, still more preferably 95 / 5 or less, from the viewpoint of transfer efficiency.

[0077] In the toner, the amorphous resin and the crystalline polyester resin are contained as a binder resin.

[0078] The total content of the amorphous resin and the crystalline 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, still more preferably 100% by mass, in the binder resin.

[0079] 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.

[0080] Examples of the release agent include hydrocarbon waxes such as polypropylene wax, polyethylene wax, polypropylene polyethylene 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.

[0081] From the viewpoint of transferability, 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 yet more preferably 100°C or lower.

[0082] From the viewpoints of the low-temperature fixability and transferability 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 2 parts by mass or more, and preferably 10 parts by mass or less, more preferably 8 parts by mass or less, still more preferably 7 parts by mass or less, and yet more preferably 4 parts by mass or less, based on 100 parts by mass of the binder resin.

[0083] From the viewpoint of low-temperature fixability, the total amount of the crystalline polyester resin and the release agent is preferably 5 parts by mass or more, more preferably 7 parts by mass or more, still more preferably 9 parts by mass or more, and preferably 40 parts by mass or less, more preferably 30 parts by mass or less, still more preferably 20 parts by mass or less, based on 100 parts by mass of the amorphous resin.

[0084] As toner raw materials, in addition to the amorphous resin and the crystalline polyester resin as the binder resin and the release agent, additives such as colorants, charge control agents, magnetic powders, fluidity improvers, conductivity adjusters, reinforcing fillers such as fibrous substances, antioxidants, and cleaning property improvers may be used.

[0085] As the colorant, dyes, pigments, magnetic materials, etc. that are used as colorants for toner 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.

[0086] From the viewpoint of improving the image density and low-temperature fixability of the toner, the content of the colorant is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and preferably 40 parts by mass or less, more preferably 20 parts by mass or less, still more preferably 10 parts by mass or less with respect to 100 parts by mass of the binder resin.

[0087] The charge control agent is not particularly limited, and may contain either a positive charge control agent or a negative charge control agent.

[0088] Examples of the positive charge control agent 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" (manufactured by Orient Chemical Industries, Ltd.); triphenylmethane dyes containing a tertiary amine as a side chain; quaternary ammonium salt compounds such as "bontron P-51" (manufactured by Orient Chemical Industries, 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.).

[0089] In addition, examples of the negatively chargeable charge control agent 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.), "Eisen Spilon Black TRH", "T-77" (manufactured by Hodogaya Chemical Co., Ltd.), etc.; metal compounds of benzoic acid compounds such as "LR-147", "LR-297" (manufactured by Nippon Carlit Co., Ltd.), etc.; 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.), etc.; copper phthalocyanine dyes; quaternary ammonium salts such as "COPY CHARGE NX VP434" (manufactured by Clariant), nitroimidazole derivatives, etc.; and organometallic compounds, etc.

[0090] 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 with respect to 100 parts by mass of the binder resin.

[0091] In the present invention, an amorphous resin, a crystalline polyester resin, a release agent, and further, if necessary, additives such as a colorant and a charge control agent are subjected to a step of melt-kneading using a twin-screw kneader.

[0092] The twin-screw kneader is a kneader that kneads and discharges the supplied raw materials while extruding them by the rotation of two screw shafts inside a cylinder (barrel). The twin-screw kneader used in the present invention is provided with two or more raw material supply ports. When the length of the barrel of the twin-screw extruder is L, one or more raw material supply ports are provided at positions f1 less than 0.3L and f2 greater than or equal to 0.3L and less than or equal to 0.9L from the inlet-side end of the barrel, respectively. The number of raw material supply ports is not particularly limited, but usually, the standard specification for the raw material supply port of the twin-screw kneader is one. Considering the cost of adding a raw material supply port and the corresponding effect, it is preferable that there are two or less at each of f1 and f2.

[0093] f1 is preferably 0.01L or more, more preferably 0.02L or more, still more preferably 0.03L or more, and is preferably 0.3L or less, more preferably 0.2L or less, still more preferably 0.1L or less.

[0094] f2 is preferably 0.3L or more, more preferably 0.35L or more, still more preferably 0.4L or more, and is preferably 0.9L or less, more preferably 0.8L or less, still more preferably 0.7L or less.

[0095] The interval between the raw material supply port F1 of f1 and the raw material supply port F2 of f2 is preferably 0.1L or more, more preferably 0.2L or more, still more preferably 0.3L or more, and is preferably 0.9L or less, more preferably 0.7L or less, still more preferably 0.5L or less. When there are a plurality of raw material supply ports F1 and raw material supply ports F2, it is preferable that the distance between the closest raw material supply port F1 and raw material supply port F2 is within the above range.

[0096] Supply the raw material containing the amorphous resin from the raw material supply port F1 of f1.

[0097] The amorphous resin supplied from the raw material supply port F1 is preferably 60% 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 of the amorphous resin contained in the toner. Here, when the raw material supply port F1 is provided with two or more raw material supply ports, the amount of the amorphous resin supplied from the raw material supply port F1 means the total of the amorphous resins supplied from those raw material supply ports.

[0098] In the raw material supplied from the raw material supply port F1, the content of the amorphous resin is preferably 60% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, and 100% by mass or less, preferably 98% by mass or less, and more preferably 96% by mass or less.

[0099] A raw material containing a crystalline polyester resin and a release agent is supplied from the raw material supply port F2 of f2.

[0100] The crystalline polyester resin supplied from the raw material supply port F2 is preferably 60% 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 of the crystalline polyester resin contained in the toner. Here, when the raw material supply port F2 is provided with two or more raw material supply ports, the amount of the crystalline polyester resin supplied from the raw material supply port F2 means the total of the crystalline polyester resins supplied from those raw material supply ports.

[0101] The release agent supplied from the raw material supply port F2 is preferably 60% 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 of the release agent contained in the toner. Here, when the raw material supply port F2 is provided with two or more raw material supply ports, the amount of the release agent supplied from the raw material supply port F2 means the total of the release agents supplied from those raw material supply ports.

[0102] Additives such as colorants and charge control agents may be supplied from either one of the raw material supply ports F1 and F2 or may be supplied separately. However, from the viewpoint of improving dispersibility, it is preferable to supply from the raw material supply port F1.

[0103] The total amount of the amorphous resin and the crystalline polyester resin supplied from the raw material supply port F2 is preferably less than 50% by mass, more preferably 40% by mass or less, still more preferably 30% by mass or less, and still more preferably 15% by mass or less, and preferably 3% by mass or more, more preferably 5% by mass or more, still more preferably 7% by mass or more, based on the total amount of the amorphous resin and the crystalline polyester resin contained in the toner.

[0104] The raw materials supplied to each raw material supply port are preferably supplied after being mixed in advance by a mixer such as a Henschel mixer or a ball mill.

[0105] The set temperature of the barrel is preferably 70°C or higher, more preferably 80°C or higher, still more preferably 90°C or higher, from the viewpoint of the fixing width, and preferably 160°C or lower, more preferably 150°C or lower, still more preferably 140°C or lower, from the viewpoint of durability.

[0106] Twin-screw extruders are classified into co-rotating type and counter-rotating type according to the rotation direction of the screw shafts. In the present invention, the co-rotating type is preferable from the viewpoints of ensuring kneading strength and material dispersibility.

[0107] After melt-kneading by a twin-screw extruder, it is preferable to appropriately cool the kneaded product until it reaches a hardness that can be pulverized, and, if necessary, perform a pulverization step and a classification step to obtain toner particles. Here, cooling means cooling the kneaded product to 0°C or higher and 50°C or lower, or cooling the kneaded product to a temperature below the glass transition temperature of the binder resin in the kneaded product.

[0108] In the pulverization step, the kneaded product may be pulverized at once to a desired particle size or may be pulverized stepwise. However, from the viewpoints of efficient and more uniform pulverization, it is preferable to perform the pulverization in two stages of coarse pulverization and fine pulverization.

[0109] Examples of the crusher used for coarse crushing include hammer mills, cutter mills, atomizers, rotorplex, etc.

[0110] In coarse crushing, it is preferable to crush until the maximum diameter becomes 3 mm or less. For example, a crushed product with a maximum diameter of 3 mm or less can be obtained by appropriately coarsely crushing 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.

[0111] Examples of the crusher used for fine crushing include jet mills such as fluidized bed jet mills and impact plate jet mills, and mechanical mills.

[0112] The degree of fine crushing is preferably adjusted as appropriate according to the particle size of the target toner particles.

[0113] Examples of the classifier used in the classification step include air classifiers, inertial classifiers, sieve classifiers, etc. During the classification step, the crushed product that has not been sufficiently crushed and removed may be returned to the crushing step, and the crushing step and the classification step may be repeated as necessary.

[0114] In the present invention, it is preferable to further have an external addition step of mixing the obtained toner particles with an external additive. A mixer such as a Henschel mixer can be used for mixing the toner particles and the external additive.

[0115] 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 kinds may be used in combination. Among these, silica is preferable, and hydrophobic silica that has been hydrophobically treated is more preferable from the viewpoint of the transferability of the toner.

[0116] Examples of the hydrophobizing agent for hydrophobizing the surface of silica particles include hexamethyldisilazane (HMDS), dimethyldichlorosilane (DMDS), cyclic silazane, silicone oil, aminosilane, octyltriethoxysilane (OTES), methyltriethoxysilane, and the like.

[0117] From the viewpoints of the chargeability, fluidity, and transferability of the toner, the average particle diameter of the external additive is preferably 5 nm or more, more preferably 10 nm or more, still more preferably 15 nm or more, and preferably 250 nm or less, more preferably 200 nm or less, still more preferably 90 nm or less.

[0118] 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, still more preferably 0.3 part by mass or more, and preferably 5 parts by mass or less, more preferably 3 parts by mass or less, based on 100 parts by mass of the toner particles before being treated with the external additive.

[0119] The volume median diameter (D 50 ) of the toner obtained by the method of the present invention 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 this specification, the volume median 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 side. Further, when the toner is treated with an external additive, the volume median diameter of the toner particles before being treated with the external additive is defined as the volume median diameter of the toner.

[0120] 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

[0121] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Physical properties such as resins can be measured by the following methods.

[0122] 〔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. Plot the plunger descent amount of the flow tester against the temperature, and the temperature at which half of the sample flows out is defined as the softening point.

[0123] 〔Maximum peak temperature of endotherm of resin〕 Using a differential scanning calorimeter "Q-100" (manufactured by TA Instruments Japan Co., Ltd.), weigh 0.01 - 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 peak temperature of endotherm.

[0124] 〔Glass transition temperature of amorphous resin〕 Using a differential scanning calorimeter "Q-100" (manufactured by TA Instruments Japan Co., Ltd.), weigh 0.01 - 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 endotherm 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.

[0125] 〔Acid value of resin〕 Measure based on the method of JIS K0070:1992. However, change the measurement solvent from the mixed solvent of ethanol and ether specified in JIS K0070 to a mixed solvent of acetone and toluene (acetone:toluene = 1:1 (volume ratio)).

[0126] 〔Melting Point of Release Agent〕 Using a differential scanning calorimeter "DSC Q20" (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 -10°C at a cooling rate of 5°C / min. Next, heat the sample up to 180°C at a heating rate of 10°C / min and measure it. The maximum peak temperature of the endotherm observed from the resulting melting endotherm curve is defined as the melting point of the release agent.

[0127] 〔Average Particle Diameter of Externally Added Agent〕 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.

[0128] 〔Volume Median Diameter (D 50 ) of Toner〕 Measuring Instrument: Coulter Multisizer II (manufactured by Beckman Coulter, Inc.) Aperture Diameter: 100 μm Analysis Software: Coulter Multisizer AccuComp Version 1.19 (manufactured by Beckman Coulter, Inc.) Electrolyte: Isoton II (manufactured by Beckman Coulter, Inc.) Dispersion Liquid: A solution prepared by dissolving Emulgen 109P (manufactured by Kao Corporation, polyoxyethylene lauryl ether, HLB (Griffin): 13.6) in the electrolyte to a concentration of 5 mass%. Dispersion Conditions: Add 10 mg of the measurement sample to 5 mL of the above dispersion liquid, 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 above electrolyte, and further disperse it for 1 minute with an ultrasonic disperser to prepare a sample dispersion liquid. Measurement Conditions: Add the above sample dispersion liquid to 100 mL of the electrolyte so that the concentration is such that the particle diameters of 30,000 particles can be measured in 20 seconds, measure 30,000 particles, and determine the volume median diameter (D 50 ) from the particle size distribution.

[0129] Resin Production Example 1 The raw material monomers of the amorphous polyester resin other than trimellitic anhydride shown in Table 1 and the esterification catalyst were placed in a 10-liter four-necked flask equipped with a nitrogen inlet tube, a water removal tube, a stirrer, and a thermocouple. After reacting at 230°C for 12 hours, the reaction was carried out at 8.3 kPa for 1 hour. The temperature was lowered to 160°C, and the raw material monomers of the styrene resin, both reactive monomers, and dicumyl peroxide were added dropwise through a dropping funnel over 1 hour. After aging the addition polymerization reaction at 160°C for 1 hour while maintaining the temperature, the temperature was raised to 210°C, and the raw material monomers of the styrene resin were removed at 8.3 kPa for 1 hour. Further, at 210°C, trimellitic anhydride was added and reacted until the desired softening point was reached to obtain an amorphous composite resin (resins H1, H2). The physical properties of the obtained resins are shown in Table 1.

[0130]

Table 1

[0131] Resin Production Example 2 The alcohol component, carboxylic acid component other than trimellitic anhydride, and esterification catalyst shown in Table 2 were placed in a 10-liter four-necked flask equipped with a nitrogen inlet tube, a water removal tube, a stirrer, and a thermocouple. The temperature was raised to 200°C and reacted for 6 hours under a nitrogen atmosphere. After further raising the temperature to 210°C, trimellitic anhydride was added and reacted at normal pressure (101.3 kPa) for 1 hour, and further reacted at 40 kPa until the desired softening point was reached to obtain an amorphous polyester resin (resins A1 to A3). The physical properties of the obtained resins are shown in Table 2.

[0132] Resin Production Example 3 The alcohol component shown in Table 2, carboxylic acid components other than trimellitic anhydride, an esterification catalyst, and a polymerization inhibitor were placed in a 10-liter four-necked flask equipped with a nitrogen inlet tube, a water removal tube, a stirrer, and a thermocouple, and heated to 200°C under a nitrogen atmosphere and reacted for 6 hours. After further heating to 210°C, trimellitic anhydride was added and reacted at normal pressure (101.3 kPa) for 1 hour, and then reacted at 40 kPa until the desired softening point was reached to obtain an amorphous polyester resin (resin A4). The physical properties of the obtained resin are shown in Table 2.

[0133]

Table 2

[0134] Resin Production Example 4 The raw material monomers of the crystalline polyester resin shown in Table 3 and an esterification catalyst were placed in a 10-liter four-necked flask equipped with a nitrogen inlet tube, a water removal tube, a stirrer, and a thermocouple, heated to 160°C, and reacted for 6 hours. Then, the raw material monomers of the styrene-based resin shown in Table 3 and both reactive monomers were dropped by a dropping funnel over 1 hour. After aging the addition polymerization reaction for 1 hour while maintaining at 160°C, the raw material monomers of the styrene-based resin were removed at 8.3 kPa for 1 hour. Further, the temperature was raised to 200°C over 8 hours and reacted at 8.3 kPa for 2 hours to obtain crystalline composite resins (resins C1, C2). The physical properties of the obtained resins are shown in Table 3.

[0135] Resin Production Example 5 The raw material monomers of the crystalline polyester resin shown in Table 3, an esterification catalyst, and a polymerization inhibitor were placed in a 10-liter four-necked flask equipped with a nitrogen inlet tube, a water removal tube, a stirrer, and a thermocouple, and the temperature was raised from 130°C to 200°C over 10 hours under a nitrogen atmosphere and reacted at 200°C at 8 kPa for 1 hour to obtain a crystalline polyester resin (resin C3). The physical properties of the obtained resin are shown in Table 3.

[0136]

Table 3

[0137] Examples 1 to 18 The amorphous resin and mold release agent (only in Example 15) supplied from the raw material supply port F1 shown in Tables 4 and 5, 1.0 part by mass of the negative charge control agent "Bontron E-304" (manufactured by Orient Chemical Industries Co., Ltd.) and 6.0 parts by mass of the colorant "REGAL330R" (manufactured by Cabot Specialty Chemicals Inc.) were mixed for 2 minutes using a Henschel mixer to obtain a raw material mixture supplied from the raw material supply port F1.

[0138] The amorphous resin (only in Example 6), crystalline polyester resin, and mold release agent supplied from the raw material supply port F2 shown in Tables 4 and 5 were mixed for 2 minutes using a Henschel mixer to obtain a raw material mixture supplied from the raw material supply port F2.

[0139] The obtained raw material mixtures were supplied from the raw material supply ports F1 and F2, respectively, to a co-rotating twin-screw extruder "PCM-43" (manufactured by Ikegai Iron Works, Ltd., shaft diameter 4.2 cm) and melt-kneaded. The length L of the barrel of the secondary extruder was 1600 mm. The raw material supply port F1 was installed at a position 75 mm (0.05L) from the inlet side end of the barrel, the raw material supply port F2 was installed at a position 695 mm (0.43L), and the kneaded product discharge port was installed at a position 1560 mm (0.98L). The operating conditions of the twin-screw extruder were adjusted such that the barrel set temperature was 120 °C, the shaft rotation speed was 150 r / min, and the mixture supply rates from the raw material supply ports F1 and F2 were such that the discharge rate of the kneaded product having a desired composition ratio was 20 kg / h.

[0140] The obtained kneaded product was cooled, roughly pulverized by a pulverizer "Rotoplex" (manufactured by Hosokawa Micron Corporation), and a roughly pulverized product having a volume particle size of 2 mm or less was obtained 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 particle size became 7.0 μm using a DS2 type air classifier (impact plate type, manufactured by Nippon Pneumatic Mfg. Co., Ltd.). The obtained finely pulverized product was classified by adjusting the static pressure (internal pressure) so that the volume median particle size became 7.5 μm using a DSX2 type air classifier (manufactured by Nippon Pneumatic Mfg. Co., Ltd.) to obtain toner particles.

[0141] 100 parts by mass of the obtained toner particles, 1.0 part by mass of hydrophobic silica "R972" (manufactured by Nippon Aerosil Co., Ltd., hydrophobizing agent: DMDS, average particle diameter: 16 nm), and 1.0 part by mass of hydrophobic silica "RY-50" (manufactured by Nippon Aerosil Co., Ltd., hydrophobizing agent: silicone oil, average particle diameter: 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 a toner.

[0142] Comparative Examples 1 to 3 Using the binder resin and release agent shown in Tables 4 and 5, these were mixed with 1.0 part by mass of the negative charge control agent "Bontron E-304" (manufactured by Orient Chemical Industries Co., Ltd.) and 6.0 parts by mass of the colorant "REGAL 330R" (manufactured by Cabot Specialty Chemicals Ink Co., Ltd.) using a Henschel mixer for 2 minutes, and a toner was obtained in the same manner as in Example 1 except that it was supplied to a twin-screw extruder from the raw material supply port F1.

[0143] Test Example 1 [Low-temperature fixability] A printer "OKI MICROLINE 5400" (manufactured by Oki Data Corporation) modified to be able to take 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 external fixing device modified from a printer "OKI MICROLINE 3010" (manufactured by Oki Data Corporation), while raising the temperature of the fixing roll from 100°C to 200°C in 5°C increments at a rotation speed of the fixing roll of 180 mm / sec, the unfixed image was fixed at each temperature to obtain a fixed image. The image obtained at each fixing temperature was rubbed 5 times back and forth with a sanding rubber (manufactured by LION Corporation, ER-502R) with a load of 500 g, and the image density before and after rubbing was measured using an image density measuring instrument X-Rite eXact (manufactured by X-Rite). 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 of low-temperature fixability. The lower the minimum fixing temperature, the better the low-temperature fixability. The results are shown in Tables 4 and 5.

[0144] Test Example 2 [Hot Offset (HO) Resistance] In the same manner as in Test Example 1, an unfixed image of a solid image with a size of 2 cm square was printed. Using an external fixing device modified from the printer "OKI MICROLINE 3010" (manufactured by Oki Data Corporation), while increasing the temperature of the fixing roll from 100 °C to 200 °C in 5 °C increments at a rotational speed of the fixing roll of 90 mm / sec, the unfixed image was fixed at each temperature to obtain a fixed image. The obtained fixed image was visually inspected, and the highest temperature of the fixing roll at which no hot offset occurred was defined as the maximum fixing temperature. The higher the temperature, the better the hot offset resistance. The results are shown in Tables 4 and 5.

[0145] Test Example 3 [Durability] 120 g of toner was installed in the non-magnetic one-component developing device "MICROLINE 5400" (manufactured by Oki Data Corporation), and a durability test was conducted at a printing rate of 3% in an environment of 30 °C and 80% humidity. A solid image was printed every 500 sheets, and it was observed whether there was any printing defect, specifically, whether there was a white streak or a smear visible enough to show the white background of the paper. The test was terminated when a printing defect was confirmed. The larger the number of printed sheets until a printing defect occurred, the better the durability. The results are shown in Tables 4 and 5.

[0146] [Table 4]

[0147] [Table 5]

[0148] From the above results, it can be seen that compared with Comparative Examples 1 to 3 in which all raw materials were supplied to the twin-screw kneader at once, the toners of Examples 1 to 18 are excellent in all of low-temperature fixability, hot offset resistance, and durability.

Industrial Applicability

[0149] The toner for electrostatic charge image development obtained by the method of the present invention is suitably used for development of latent images formed in electrophotography, electrostatic recording, electrostatographic printing, and the like.

Claims

1. A method for producing an electrostatic charge image developing toner, comprising a step of melt-kneading a mixture of raw materials containing an amorphous resin, a crystalline polyester resin, and a release agent using a twin-screw extruder. When the length of the barrel of the twin-screw extruder is L, there are one or more raw material supply ports at positions f1 less than 0.3L and positions f2 greater than or equal to 0.3L and less than or equal to 0.9L from the inlet-side end of the barrel. A raw material containing an amorphous resin is supplied from the raw material supply port F1 at f1, and a raw material containing a crystalline polyester resin and a release agent is supplied from the raw material supply port F2 at f2. The amorphous resin supplied from the raw material supply port F1 is 60% by mass or more of the amorphous resin contained in the toner, and the crystalline polyester resin supplied from the raw material supply port F2 is 60% by mass or more of the crystalline polyester resin contained in the toner. A method for producing an electrostatic charge image developing toner.

2. The production method according to claim 1, wherein the release agent supplied from the raw material supply port F2 is 60% by mass or more of the release agent contained in the toner.

3. The production method according to claim 1 or 2, wherein the total amount of the amorphous resin and the crystalline polyester resin supplied from the raw material supply port F2 is less than 50% by mass of the total amount of the amorphous resin and the crystalline polyester resin contained in the toner.

4. The production method according to any one of claims 1 to 3, wherein the total amount of the crystalline polyester resin and the release agent is 5 parts by mass or more and 40 parts by mass or less with respect to 100 parts by mass of the amorphous resin.

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