Toner, toner cartridge, and image forming apparatus

Abstract

To provide a toner excellent in low-temperature fixability, preservability and adhesiveness.SOLUTION: A toner comprising at least a base particle and an external additive, wherein the base particle contains an amorphous polyester resin and a crystalline polyester resin, and a volume V of an overlapping portion of Hansen solubility spheres of the amorphous polyester resin and the crystalline polyester resin based on the theory of Hansen solubility parameters is from 200 (J / cm3) 3 / 2 to 800 (J / cm3) 3 / 2. Alternatively, a value (V·X) / 100 of 1 / 100 of a product of a volume V (J / cm3) 3 / 2 of the overlapping portion and the content ratio X mass% of the crystalline polyester resin in the toner base particles is from 20 (J / cm3) 3 / 2 to 80 (J / cm3) 3 / 2.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a toner having excellent low-temperature fixability, storage stability and adhesion, a toner cartridge filled with the toner, and an image forming apparatus. [Background technology]

[0002] Electrostatic image developing toners are used in image forming devices such as printers, copiers, and facsimiles to visualize electrostatic images. For example, in electrophotographic image formation, an electrostatic latent image is first formed on a photoreceptor drum. This electrostatic latent image is then developed with toner, transferred to a printing medium such as transfer paper, and the toner is heated to fix the image.

[0003] In recent years, toner-based machines have been used not only in printers and copiers for office and home printing, but also in commercial printing machines such as label printing machines, and their applications are expanding.

[0004] Toners used for developing electrostatic images generally have a structure in which solid fine particles such as silica are attached as an external additive to the surfaces of toner base particles containing a binder resin, a colorant, a wax, etc. Styrene-acrylic resins or polyester resins are usually used as the binder resin for the toner base particles.

[0005] When forming an image on a print medium, the toner is heated to fix it. However, since the electricity required for this heating accounts for the majority of the power consumption of image forming devices such as copiers, toner is required to have the ability to fix at lower temperatures (low-temperature fixability).

[0006] Furthermore, in the aforementioned commercial printing, the printing medium is often not only conventional paper but also plastic films such as polypropylene (PP) and polyethylene terephthalate (PET), and since the film will deteriorate if exposed to too much heat, even better low-temperature fixability than that of conventional paper media is required.

[0007] Patent Document 1 proposes a toner for developing electrostatic images that has excellent low-temperature fixing properties, the toner having a core-shell structure in which a shell is provided on the surface of a core particle, in which a styrene acrylic resin is used as the binder resin for the core and an amorphous polyester resin is used as the binder resin for the shell, and the binder resin for the shell has a predetermined low viscosity, specifically, a storage modulus at 70°C (G'(70°C)) of 500,000 Pa or more and a storage modulus at 100°C (G'(100°C)) of 5,000 Pa or less.

[0008] Furthermore, Patent Document 2 discloses an electrophotographic toner that can be fixed at low temperatures and can obtain an appropriate amount of triboelectric charge, and that contains a crystalline resin in an amount of 50% by weight or more and has a specific electrical resistance and a specific amount of triboelectric charge. Specific examples of the crystalline resin include crystalline polyesters that use aliphatic dicarboxylic acids such as sebacic acid and 1,10-decanedicarboxylic acid as raw carboxylic acid components. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 2023-147690 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-191623 Summary of the Invention [Problem to be solved by the invention]

[0010] The toner of Patent Document 1 has insufficient low-temperature fixability for use in printing on plastic films. Furthermore, when the low-temperature fixing property of a toner resin containing a crystalline polyester is increased, the resin tends to stick and its storage stability decreases. However, Patent Document 2 does not disclose any of the above problems or means for solving them.

[0011] SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a toner that has excellent storage stability while maintaining excellent low-temperature fixability and adhesion. [Means for solving the problem]

[0012] The present inventors have conducted extensive research to solve the above-mentioned problems, and have found that the above-mentioned problems can be solved by providing a toner containing at least base particles and external additives, in which the amorphous polyester resin and crystalline polyester resin contained in the base particles satisfy a specific relationship in the volume V of the overlapping portion of each Hansen solubility sphere based on the Hansen solubility parameter theory. That is, the present invention is summarized as follows.

[0013] [1] A toner comprising at least base particles and an external additive, the base particles contain an amorphous polyester resin and a crystalline polyester resin, Based on the Hansen solubility parameter theory, the volume V of the overlapping portion of the Hansen solubility spheres of the amorphous polyester resin and the crystalline polyester resin is 200 (J / cm 3 ) 3 / 2 More than 800(J / cm 3 ) 3 / 2 The toner is as follows:

[0014] [2] A toner comprising at least base particles and an external additive, the base particles contain an amorphous polyester resin and a crystalline polyester resin, Based on the Hansen solubility parameter theory, the volume V (J / cm) of the overlapping area of ​​the Hansen solubility spheres of the amorphous polyester resin and the crystalline polyester resin 3 ) 3 / 2 and the content ratio X mass % of the crystalline polyester resin in the toner base particles, the value (V·X) / 100 being 1 / 100, is 20 (J / cm 3 ) 3 / 2 Above, 80(J / cm 3 ) 3 / 2 The toner is as follows:

[0015] [3] The crystalline polyester resin is a polycondensate of a carboxylic acid component and an alcohol component, The toner according to [1] or [2], wherein the carboxylic acid component contains at least sebacic acid, and the alcohol component contains at least ethylene glycol and propylene glycol.

[0016] [4] Based on the Hansen solubility parameter theory of the amorphous polyester resin, the values ​​of the dispersion term δD, polar term δP, and hydrogen bond term δH are in the range of 6 (J / cm 3 ) 1 / 2 ~12(J / cm 3 ) 1 / 2 , the range of polarity term δP is 15 (J / cm 3 ) 1 / 2 ~22(J / cm 3 ) 1 / 2 , the range of the hydrogen bond term δH is 6 (J / cm 3 ) 1 / 2 ~12(J / cm 3 ) 1 / 2 The toner according to any one of [1] to [3], wherein

[0017] [5] The base particle has a core-shell structure, and the amorphous polyester resin and the crystalline polyester resin contained in the core of the core-shell structure have a volume V of the overlapping portion or a volume V (J / cm 3 ) 3 / 2 and a content ratio X mass % of the crystalline polyester resin in the toner base particles, (V·X) / 100, which is 1 / 100 of the product.

[0018] [6] The toner according to any one of [1] to [5], wherein the total content of bisphenol A and other compounds having a bisphenol structure in the toner is less than 100 ppm.

[0019] [7] The toner according to any one of [1] to [6], wherein the total content of trimellitic anhydride and trimellitic acid in the toner is less than 1000 ppm.

[0020] [8] The toner according to any one of [1] to [7], wherein the melting point of the crystalline polyester resin is 62° C. or higher and 90° C. or lower.

[0021] [9] The toner according to any one of [1] to [8], wherein the base particles further contain a colorant.

[0022]

[10] The toner according to any one of [1] to [9], which has a volume median particle size (Dv50) of 3.0 μm or more and 7.0 μm or less.

[0023]

[11] The toner according to any one of [1] to

[10] , having an average circularity of 0.92 or more and 0.99 or less.

[0024]

[12] A toner cartridge filled with the toner according to any one of [1] to

[11] .

[0025]

[13] An image forming apparatus using the toner according to any one of [1] to

[11] . [Effects of the Invention]

[0026] According to the present invention, there are provided a toner that has excellent storage stability while maintaining excellent low-temperature fixability and adhesion, and a toner cartridge and an image forming apparatus that use this toner. DETAILED DESCRIPTION OF THE INVENTION

[0027] The following describes in detail the mode for carrying out the present invention (hereinafter referred to as "embodiments of the invention"). Note that the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the invention.

[0028] In this specification, when the expression "X to Y" (X and Y are any numbers) is used, unless otherwise specified, it means "X or more and Y or less," and also includes the meaning of "preferably larger than X" or "preferably smaller than Y." Furthermore, when it is expressed as "X or more" (X is any number) or "Y or less" (Y is any number), it also includes the intention that "it is preferable that it is greater than X" or "it is preferable that it is less than Y."

[0029] [toner] The toner of the present invention is a toner containing at least base particles (hereinafter sometimes referred to as "the toner base particles") and an external additive, and the toner base particles contain an amorphous polyester resin and a crystalline polyester resin.

[0030] The toner according to one embodiment of the present invention (hereinafter, sometimes referred to as "Toner I of the present invention" or "Toner I") has a volume V of the overlapping portion of the Hansen solubility spheres of the amorphous polyester resin and the crystalline polyester resin in the toner base particles (hereinafter, sometimes simply referred to as "overlapping volume V of the solubility spheres") of 200 (J / cm) based on the Hansen solubility parameter theory. 3 ) 3 / 2 More than 800(J / cm 3 ) 3 / 2 The present invention is characterized by the following: The toner according to another embodiment of the present invention (hereinafter, sometimes referred to as "toner II of the present invention" or "present toner II") has a volume V (J / cm) of the overlapping part of the Hansen solubility spheres of the amorphous polyester resin and the crystalline polyester resin in the present toner base particles, which is based on the Hansen solubility parameter theory. 3 ) 3 / 2 and the content ratio X mass% of the crystalline polyester resin in the toner base particles, which is 1 / 100 of the product (V·X) / 100 (hereinafter, simply referred to as "(V·X) / 100"), is 20 (J / cm 3 ) 3 / 2 Above, 80(J / cm 3 ) 3 / 2 The present invention is characterized by the following:

[0031] The overlap volume V of the dissolving spheres and the values ​​of the dispersion term δD, polar term δP, and hydrogen bond term δH described below can be determined according to the method described in the Examples section below. Hereinafter, "Toner I" and "Toner II" will be collectively referred to as "Toner" or "Toner of the present invention." The toner base particles containing the amorphous polyester resin and the crystalline polyester resin may further contain a colorant and / or a wax, and preferably contain a colorant. The toner base particles may also contain a charge control agent and other components as needed.

[0032] <Overlap volume of melting spheres V> In this toner I, the overlap volume V of the melting sphere is 200 (J / cm 3 ) 3 / 2 More than 800(J / cm 3 ) 3 / 2 The overlapping volume V of the melting sphere is 200 (J / cm 3 ) 3 / 2 If the viscosity of the toner is lower than 800 (J / cm), excellent low-temperature fixability and adhesion can be obtained. 3 ) 3 / 2 If the melting sphere volume V is less than 300 to 700 (J / cm), the storage stability will not be impaired. 3 ) 3 / 2 The range is preferably 400 to 600 (J / cm 3 ) 3 / 2 It is preferable that the range is:

[0033] In order for the amorphous polyester resin and the crystalline polyester resin to fill the overlap volume V of the dissolved spheres, methods for this toner I include controlling the crystallinity of the crystalline polyester resin relative to the structure of the amorphous polyester resin to make the amorphous portion in the crystalline structure more compatible, or combining a monomer component of the amorphous polyester with a monomer component of the crystalline polyester, such as ethylene glycol as an alcohol component.

[0034] <(V·X) / 100> In this toner II, (V·X) / 100 is 20(J / cm 3 ) 3 / 2Above, 80(J / cm 3 ) 3 / 2 (V·X) / 100 is 20(J / cm 3 ) 3 / 2 If the toner viscosity is lower than this, excellent low-temperature fixability and adhesion can be obtained. On the other hand, if (V·X) / 100 is 80 (J / cm 3 ) 3 / 2 If it is less than this, the storage stability will not be impaired. From the viewpoint of achieving both low-temperature fixability, adhesion, and storage stability, (V·X) / 100 is 30 to 70 (J / cm 3 ) 3 / 2 The range is preferably 40 to 60 (J / cm 3 ) 3 / 2 It is preferable that the range is:

[0035] In order to satisfy the above (V·X) / 100, one method is to control the crystallinity of the crystalline polyester resin relative to the structure of the amorphous polyester resin in Toner II, making it easier for the amorphous component in the crystal to blend in, and to adjust the content ratio X mass% of the crystalline polyester resin in the toner base particles; in other words, to reduce the amount of crystalline polyester added when combining an amorphous polyester and a crystalline polyester with a large overlap volume, and to increase the amount added when combining an amorphous polyester and a crystalline polyester with a small overlap volume.

[0036] <Hansen solubility parameters> The compatibility of amorphous polyester and crystalline polyester can be explained using Hansen solubility parameters. The Hansen solubility parameters are the solubility parameters introduced by Hildebrand, divided into three components: dispersion term (δD), polar term (δP), and hydrogen bonding term (δH), and are expressed in three-dimensional space. The dispersion term (δD) indicates the effect of dispersion forces, the polar term (δP) indicates the effect of dipole-dipole forces, and the hydrogen bonding term (δH) indicates the effect of hydrogen bonding forces.

[0037] The definition and calculation of the Hansen solubility parameter are described in Charles M. Hansen, Hansen Solubility Parameters: A Users Handbook (CRC Press, 2007). Furthermore, by using the computer software Hansen Solubility Parameters in Practice (HSPiP), the Hansen solubility parameter can be easily estimated from the chemical structure of compounds for which literature values ​​are unknown. Furthermore, for compounds for which literature values ​​are unknown, the Hansen solubility parameter can also be calculated using the dissolving sphere method described below. In this invention, HSPiP version 5.4.08 was used, and the registered Hansen solubility parameter values ​​were used for solvents registered in the database. The Hansen solubility parameter of each resin was calculated using the dissolving sphere method described below.

[0038] The dissolving sphere method is a method for calculating the Hansen solubility parameter of a target substance. The Hansen solubility parameter is determined by a solubility test in which the target substance is dissolved or dispersed in a number of different solvents for which the Hansen solubility parameter has been established, and the solubility or dispersibility of the target substance in a specific solvent is evaluated. The types of solvents used in the solubility test are preferably selected so that the sum of the dispersion term, polarity term, and hydrogen bonding term of the HSP of each solvent varies widely among the solvents. More specifically, it is preferable to evaluate using at least seven, more preferably at least ten, and even more preferably at least fifteen different solvents. Specifically, among the solvents used in the solubility test, a sphere with the smallest radius (dissolving sphere) is found, such that all three-dimensional points of the solvent that dissolved or dispersed the target substance are contained within the sphere, and points of the solvent that did not dissolve the target substance are outside the sphere. The central coordinates of this sphere are used as the Hansen solubility parameter of the target substance. The radius of the dissolving sphere is used as the interaction radius R. Solubility and dispersibility are evaluated by determining whether the target substance is dissolved or dispersed in the solvent. The specific method for the solubility test will be described in detail in the Examples section.

[0039] For example, the closer the coordinate point indicated by the Hansen solubility parameters of one substance a is to the coordinate point indicated by the Hansen solubility parameters of another substance b, the more compatible the substances are considered to be. Also, if the solubility sphere of one substance a is enclosed inside the solubility sphere of substance b, it is considered that substance a will easily dissolve or disperse in substance b. On the other hand, the less overlapping the solubility spheres are, the more difficult it is considered that dissolution and dispersion will be.

[0040] <Dispersion term δD, polarity term δP, hydrogen bond term δH> Of the dispersion term δD, polar term δP, and hydrogen bond term δH based on the Hansen solubility parameter theory of the amorphous polyester resin contained in the toner of the present invention, the dispersion term δD is 6 (J / cm 3 ) 1 / 2 ~12(J / cm 3 ) 1 / 2 The range is preferably 7 to 11 (J / cm 3 ) 1 / 2 More preferably, it is 8 to 10 (J / cm 3 ) 1 / 2 If the value of the dispersion term ΔD is equal to or greater than the above lower limit, the affinity of the crystalline polyester with the amorphous portion increases, and the effect of reducing the viscosity when the crystalline polyester is melted at high temperatures becomes significant, whereas if the value is equal to or less than the above upper limit, the affinity of the crystalline polyester with the amorphous portion decreases appropriately, and the crystalline polyester becomes more easily dispersed at low temperatures, resulting in high storage stability.

[0041] Of the dispersion term δD, polar term δP, and hydrogen bond term δH based on the Hansen solubility parameter theory of the amorphous polyester resin contained in the toner of the present invention, the polar term δP is 15 (J / cm 3 ) 1 / 2 ~22(J / cm 3 ) 1 / 2 The range is preferably 16 to 21 (J / cm 3 ) 1 / 2 More preferably, it is 17 to 20 (J / cm 3 ) 1 / 2If the value of the polarity term ΔP is equal to or greater than the above lower limit, the stability of the resin solution increases, and the affinity of the crystalline polyester with the resin solution increases during primary aggregation to form base particles, thereby improving dispersibility, whereas if the value is equal to or less than the above upper limit, the emulsion aggregation properties increase, and the amorphous polyester and the crystalline polyester are less likely to separate during melting to form base particles.

[0042] Of the dispersion parameter δD, polar parameter δP, and hydrogen bond parameter δH based on the Hansen solubility parameter theory of the amorphous polyester resin contained in the toner of the present invention, the hydrogen bond parameter δH is 6 (J / cm 3 ) 1 / 2 ~12(J / cm 3 ) 1 / 2 The range is preferably 7 to 11 (J / cm 3 ) 1 / 2 More preferably, it is 8 to 10 (J / cm 3 ) 1 / 2 If the value of the hydrogen bond parameter δH is equal to or higher than the above lower limit, the affinity of the crystalline polyester to the crystalline portion increases, making it easier to retain the crystalline polyester inside the particle, and if it is equal to or lower than the above upper limit, the affinity of the crystalline polyester to the crystalline portion decreases appropriately, making it easier for the crystalline polyester to disperse at low temperatures, thereby improving storage stability.

[0043] An amorphous polyester resin satisfying the above values ​​of dispersion parameter ΔD, polar parameter ΔP, and hydrogen bond parameter ΔH can be produced, for example, by combining an alcohol monomer component and a carboxylic acid monomer component, which will be described later.

[0044] <Regarding environmental impact> Toners for developing electrostatic images in commercial label printing machines and other printers are often required to have low-temperature fixability and low environmental impact. For food packaging applications, environmental hormones, which disrupt the natural hormone functions of living organisms, are particularly problematic. In polyester toner, bisphenol A derivatives are commonly used as polyester resin monomers from the perspectives of offset resistance, low-temperature fixability, and control of charging characteristics. However, bisphenol A has been found to exhibit estrogen-like effects (estrogen: female hormone), and it has been pointed out that it specifically binds to certain receptors and acts as a substance that activates them. It is now considered an endocrine disruptor and an environmental hormone, and in recent years, there has been a growing movement around the world to restrict its use. For example, in Europe, it was added to the list of substances of very high concern (SVHC) under the European REACH regulation in 2017. There is also a movement to restrict the use of trimellitic anhydride, which is commonly used as an acid monomer for polyester resins, due to its toxicity to the human body (respiratory sensitization). Furthermore, it is desirable to minimize contamination with heavy metals originating from heavy metal catalysts used as catalysts for polyester resins.

[0045] For these reasons, the total content of bisphenol A and other compounds having a bisphenol structure in the present toner is preferably less than 100 ppm, more preferably less than 50 ppm, and even more preferably less than 10 ppm. Therefore, in producing the present toner, it is preferable to avoid using bisphenol A and other compounds having a bisphenol structure as much as possible.

[0046] Furthermore, in the present toner, the total content of trimellitic anhydride and compounds containing trimellitic acid is preferably less than 1000 ppm, more preferably less than 500 ppm, and even more preferably less than 100 ppm. Therefore, in producing the present toner, it is preferable to avoid using trimellitic anhydride, trimellitic acid, and derivative compounds thereof as much as possible.

[0047] <Toner base particles> The base particles of the toner (the toner base particles) contain an amorphous polyester resin and a crystalline polyester resin. In order to obtain the effects of the present invention more effectively, it is preferable that the toner base particles have a core-shell structure, and it is more preferable that the core binder resin contains an amorphous polyester resin and a crystalline polyester, and the shell binder resin contains an amorphous polyester resin. In this case, the amorphous polyester resin and crystalline polyester resin contained in the core need only satisfy the above-mentioned melt sphere overlap volume V or (V·X) / 100, and there are no particular restrictions on the amorphous polyester resin contained in the shell. It is also preferable that the amorphous polyester resin of the core also satisfies the above-mentioned preferred ranges for the dispersion term δD, polarity term δP, and hydrogen bond term δH, and there are no particular restrictions on the amorphous polyester resin of the shell.

[0048] In the present invention, the term "core-shell structure" refers to a structure in which the surface of a core component is covered with a shell component, but is not limited to a structure in which the core component is completely covered with the shell component, and the surface of the core component may be partially exposed, or may be partially dispersed in the shell component.

[0049] In any of the methods for preparing toner base particles described below, the shell component refers to a component that is unevenly distributed on the surface of the toner base particle. The shape of the shell component when made into a toner may be a fine particle or a thin film, and further, the shell component may cover the core component continuously or discontinuously.

[0050] When toner base particles are produced in a wet medium having an aqueous and / or organic solvent as a continuous phase, there are two methods: one is to add shell particles simultaneously with the core components and thermodynamically arrange the shell particles at the interface between the core components and the wet medium (method to control polarity), and the other is to add shell particles after the core components and physically arrange them on the surface of the core components.Furthermore, it is also possible to combine the method of thermodynamically arranging shell particles at the interface between the core components and the wet medium (method to control polarity) and the method of adding shell particles after the core components and physically arrange them on the surface of the core components.

[0051] In addition, when adding shell microparticles after the core component, a method of adding them after the composition and / or shape of the core component has been determined (the shape, physical properties, compatibility, etc. of the core component may change due to subsequent heating, aging, stirring, etc.) can also be used.

[0052] As described above, the toner base particles may further contain a colorant, a wax, a charge control agent, and other components as necessary. When the toner base particles have a core-shell structure, these components may be contained in either the core or the shell, but are preferably contained in the core.

[0053] <Amorphous polyester resin> Amorphous polyester resin refers to a polyester resin that has a glass transition point (Tg) in an endothermic curve obtained by differential scanning calorimetry (DSC), but exhibits amorphous properties with no clear endothermic peak at the melting point, i.e., when the temperature rises.

[0054] The amorphous polyester resin is obtained by polycondensation reaction of raw materials, a carboxylic acid component containing a polycarboxylic acid monomer (derivative) and an alcohol component containing a polyhydric alcohol monomer (derivative), in the presence of an appropriate polymerization catalyst. Examples of the polycarboxylic acid monomer derivatives that can be used include alkyl esters, acid anhydrides, and acid chlorides of polycarboxylic acid monomers, and examples of the polyhydric alcohol monomer derivatives that can be used include esters of polyhydric alcohol monomers and hydroxycarboxylic acids.

[0055] Examples of polycarboxylic acid monomers include oxalic acid, succinic acid, maleic acid, adipic acid, β-methyladipic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, fumaric acid, citraconic acid, diglycolic acid, cyclohexane-3,5-diene-1,2-dicarboxylic acid, malic acid, citric acid, hexahydroterephthalic acid, malonic acid, pimelic acid, tartaric acid, mucic acid, phthalic acid, isophthalic acid, terephthalic acid, tetrachlorophthalic acid, chlorophthalic acid, nitrophthalic acid, p-caprylic acid, benzoic ... Examples of suitable carboxylic acids include dicarboxylic acids such as carboxyphenylacetic acid, p-phenylenediacetic acid, m-phenylenediglycolic acid, p-phenylenediglycolic acid, o-phenylenediglycolic acid, diphenylacetic acid, diphenyl-p,p'-dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, anthracenedicarboxylic acid, and dodecenylsuccinic acid; and tricarboxylic acids such as naphthalenetricarboxylic acid, naphthalenetetracarboxylic acid, pyrenetricarboxylic acid, and pyrenetetracarboxylic acid. These may be used alone or in combination of two or more. Among these, from the viewpoints of storage stability, handling properties, cost, and supply amount of the toner, preferred dicarboxylic acids are maleic acid, adipic acid, fumaric acid, cyclohexane-3,5-diene-1,2-dicarboxylic acid, isophthalic acid, and terephthalic acid, more preferred are adipic acid, isophthalic acid, and terephthalic acid, and even more preferred are isophthalic acid and terephthalic acid.

[0056] Examples of polyhydric alcohol monomers include dihydric alcohols such as ethylene glycol, neopentyl glycol, propylene glycol, butanediol, diethylene glycol, hexanediol, cyclohexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, octanediol, decanediol, and dodecanediol; and trihydric or higher polyols such as glycerin, pentaerythritol, trimethylolpropane, hexamethylolmelamine, hexaethylolmelamine, tetramethylolbenzoguanamine, and tetraethylolbenzoguanamine. These may be used alone or in combination of two or more. Among these, as the dihydric alcohol, ethylene glycol, neopentyl glycol, and 1,4-cyclohexanedimethanol are preferred, and ethylene glycol and neopentyl glycol are more preferred, from the viewpoints of reducing the colorability of the resin, ease of availability of raw materials, and charging properties. As the trivalent or higher polyol, from the viewpoint of ease of adjusting the polymerization rate, glycerin, pentaerythritol, and trimethylolpropane are preferred, and trimethylolpropane is more preferred.

[0057] To ensure that the amorphous polyester resin satisfies the aforementioned values ​​for the melt sphere overlap volume V, (V·X) / 100, as well as the dispersion parameter δD, polar parameter δP, and hydrogen bond parameter δH, it is preferable that the amorphous polyester resin used for the core of the core-shell structure be made from a combination of terephthalic acid and isophthalic acid as dicarboxylic acids, a combination of ethylene glycol and neopentyl glycol as dihydric alcohols, and trimethylolpropane as a trihydric polyol, with appropriate crosslinking.

[0058] The ratio of polycarboxylic acid monomer (derivative) and polyhydric alcohol monomer (derivative) to be subjected to the polycondensation reaction when producing the amorphous polyester resin is preferably such that the equivalent ratio (OH) / (COOH) of the hydroxyl group (OH) of the polyhydric alcohol to the carboxyl group (COOH) of the polycarboxylic acid is within the range of 1.5 / 1 to 1 / 1.5.

[0059] From the viewpoint of achieving both high strength and low-temperature fixability of the printed image, it is preferable that the glass transition temperature (Tg) of the amorphous polyester resin is within the range of 45°C or higher and 65°C or lower. However, the more preferable range of the glass transition temperature (Tg) of the amorphous polyester resin for core use differs slightly from that for shell use, as described below.

[0060] The glass transition temperature (Tg) of the amorphous polyester resin for core use is preferably within the range of 45 to 60°C. If the glass transition temperature of the amorphous polyester resin is above the lower limit, a toner with high storage stability and excellent practicality can be obtained. If the glass transition temperature of the amorphous polyester resin is below the upper limit, the target low-temperature fixability can be achieved by combining it with an appropriate crystalline polyester. The glass transition temperature is more preferably 50°C or higher, even more preferably 53°C or higher, and more preferably 58°C or lower, even more preferably 56°C or lower.

[0061] The glass transition temperature (Tg) of the amorphous polyester resin used for the shell is preferably in the range of 53 to 65°C. If the glass transition temperature of the amorphous polyester resin is at or above the lower limit, the storage stability is high and a toner with excellent practicality can be obtained. If the glass transition temperature of the amorphous polyester resin is at or below the upper limit, the low-temperature fixability is not significantly deteriorated. The glass transition temperature is more preferably 54°C or higher, even more preferably 58°C or higher, and more preferably 62°C or lower.

[0062] The glass transition temperature of the amorphous polyester resin is measured by the method described in the Examples section below.

[0063] The softening temperature of the amorphous polyester resin for core use is preferably in the range of 95 to 130°C. If the softening temperature is above the lower limit, a toner with high storage stability and excellent practicality can be obtained. If the softening temperature is below the upper limit, low-temperature fixability is not significantly deteriorated. The softening temperature is more preferably 100°C or higher, even more preferably 105°C or higher, and more preferably 125°C or lower, even more preferably 120°C or lower.

[0064] The softening temperature of the amorphous polyester resin for the shell is preferably in the range of 105 to 140°C. If the softening temperature is above the lower limit, a toner with high storage stability and excellent practicality can be obtained. If the softening temperature is below the upper limit, the target low-temperature fixability can be achieved by combining it with an appropriate crystalline polyester. The softening temperature is more preferably 110°C or higher, even more preferably 115°C or higher, and more preferably 135°C or lower, even more preferably 130°C or lower.

[0065] The softening temperature of the amorphous polyester resin is measured by the method described in the Examples section below.

[0066] The acid value of the amorphous polyester resin is preferably 4 mgKOH / g or more. If the acid value is equal to or greater than the lower limit, the polyester dispersion can be sufficiently stable for use in the aggregation process of toner base particle production. On the other hand, an acid value of 20 mg KOH / g or less is preferred from the viewpoint of ease of production of aggregated particles. If the acid value is higher than 20 mg KOH / g, the dispersion is highly stable and aggregation is difficult. The acid value of the amorphous polyester resin is more preferably 5 mgKOH / g or more, and even more preferably 6 mgKOH / g or more, and is more preferably 18 mgKOH / g or less, and even more preferably 15 mgKOH / g or less.

[0067] The acid value of the amorphous polyester resin is measured by the method described in the Examples section below.

[0068] The amorphous polyester resin preferably has a polystyrene-equivalent weight average molecular weight (Mw) of 5,000 to 30,000 as measured by gel permeation chromatography (GPC). High storage stability can be achieved by making the mass average molecular weight (Mw) of the amorphous polyester resin 5,000 or more, and complex viscosity can be reduced by making the mass average molecular weight (Mw) of the amorphous polyester resin 30,000 or less. The method for measuring the mass average molecular weight (Mw) of the amorphous polyester resin is as described in the Examples section below.

[0069] The toner base particles may contain only one type of amorphous polyester resin in each of the core and shell, or may contain two or more types with different monomer compositions, physical properties, etc. Furthermore, the amorphous polyester resin in the core and the amorphous polyester resin in the shell may be the same or different.

[0070] The amorphous polyester resin constituting the core is preferably contained in a proportion of 60% by mass or more and 85% by mass or less relative to the total mass of the toner base particles. If the content of the amorphous polyester resin constituting the core in the toner base particles is 60% by mass or more, a toner with excellent fixability to printed matter can be obtained. From this perspective, the content of the amorphous polyester resin constituting the core in the toner base particles is particularly preferably 63% by mass or more, and even more preferably 65% ​​by mass or more. On the other hand, if the content of the amorphous polyester resin constituting the core in the toner base particles is 85% by mass or less, a toner with excellent storage stability can be obtained. From this perspective, the content of the amorphous polyester resin constituting the core in the toner base particles is particularly preferably 83% by mass or less, and even more preferably 80% by mass or less.

[0071] Furthermore, the amorphous polyester resin constituting the shell is preferably contained in a proportion of 5% by mass or more and 20% by mass or less relative to the total mass of the toner base particles. If the content of the amorphous polyester resin constituting the shell in the toner base particles is 5% by mass or more, a toner with excellent storage stability is obtained. From this perspective, the content of the amorphous polyester resin constituting the shell in the toner base particles is particularly preferably 7% by mass or more, and even more preferably 10% by mass or more. On the other hand, if the content of the amorphous polyester resin constituting the shell in the toner base particles is 20% by mass or less, a toner with excellent fixability to printed matter is obtained. From this perspective, the content of the amorphous polyester resin constituting the shell in the toner base particles is particularly preferably 17% by mass or less, and even more preferably 15% by mass or less.

[0072] The total content of the amorphous polyester resin in the toner base particles is preferably 65% ​​by mass or more and 90% by mass or less, based on the total mass of the toner base particles. If the total content of the amorphous polyester resin in the toner base particles is 65% by mass or more, a toner with excellent fixability to printed matter can be obtained. From this perspective, the total content of the amorphous polyester resin in the toner base particles is particularly preferably 70% by mass or more, and even more preferably 75% by mass or more. On the other hand, if the total content of the amorphous polyester resin in the toner base particles is 90% by mass or less, it is possible to add a sufficient amount of wax or crystalline polyester to achieve functionality. From this perspective, the total content of the amorphous polyester resin in the toner base particles is particularly preferably 85% by mass or less, and even more preferably 80% by mass or less.

[0073] <Crystalline polyester resin> The crystalline polyester resin means a polyester resin that has a crystalline melting peak when measured by a differential scanning calorimeter (DSC).

[0074] The crystalline polyester resin is obtained by a polycondensation reaction in the presence of an appropriate polymerization catalyst using as raw materials a carboxylic acid component containing a dicarboxylic acid monomer (including derivatives; hereinafter, sometimes referred to as a "dicarboxylic acid component") and an alcohol component containing an aliphatic dialcohol monomer (including derivatives; hereinafter, sometimes referred to as an "aliphatic dialcohol component").

[0075] In the present toner, it is preferable to use, as the crystalline polyester resin, a polycondensation product of an alcohol component containing ethylene glycol and propylene glycol and a carboxylic acid component containing sebacic acid. In other words, by using ethylene glycol and propylene glycol as the alcohol component and sebacic acid as the carboxylic acid component, the crystallinity of the crystalline polyester resin is adjusted to a suitable level, increasing its solubility in the solvent. This makes it easier to satisfy the aforementioned values ​​for the overlap volume V and (V·X) / 100 of the dissolved spheres, while also improving the stability of the emulsion during production, resulting in a toner with excellent low-temperature fixing properties, adhesion, and storage stability. From this viewpoint, the total content of ethylene glycol and propylene glycol in the alcohol component is preferably 50 to 100 mol %, more preferably 70 to 100 mol %, and even more preferably 90 to 100 mol %. Furthermore, the content of ethylene glycol in the alcohol component is preferably 80 to 98.5 mol % and the content of propylene glycol is preferably 1.5 to 20 mol %, more preferably 90 to 97 mol % and 3 to 10 mol %, and even more preferably 93 to 96 mol % and 4 to 7 mol %. If the amount of propylene glycol is less and the amount of ethylene glycol is more than the above range, the effect of using propylene glycol to reduce crystallinity and increase solubility in solvents and emulsion stability cannot be fully obtained. Conversely, if the amount of propylene glycol is more and the amount of ethylene glycol is less than the above range, the crystallinity will be too low, the melting point will be lowered, and the storage stability of the toner will tend to deteriorate.

[0076] The content of sebacic acid in the carboxylic acid component is preferably 80 to 100 mol%, particularly 90 to 100 mol%, and especially 95 to 100 mol%. By using sebacic acid in an amount equal to or greater than the lower limit, the carbon chain length increases, increasing crystallinity and improving dispersibility within the core resin.

[0077] When an alcohol component other than ethylene glycol and propylene glycol is used in the production of the crystalline polyester resin, examples of the other alcohol component include one or more aliphatic dialcohols such as 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,15-pentadecanediol, and 1,16-hexadecanediol. Furthermore, when a carboxylic acid component other than sebacic acid is used, examples of the other carboxylic acid component include one or more dicarboxylic acids such as fumaric acid, succinic acid, adipic acid, sebacic acid, dodecanedioic acid, tetradecanedioic acid, terephthalic acid, and isophthalic acid.

[0078] The ratio of the dicarboxylic acid component and the aliphatic dialcohol component to be subjected to the polycondensation reaction when producing the crystalline polyester resin is preferably such that the equivalent ratio (OH) / (COOH) of the hydroxy group (OH) of the aliphatic alcohol component to the carboxy group (COOH) of the dicarboxylic acid component is within the range of 1.5 / 1 to 1 / 1.5.

[0079] The melting point (Tm) of the crystalline polyester resin is preferably in the range of 62 to 90°C, particularly 66 to 86°C. If the melting point is above the lower limit, blocking of the toner particles is not significantly worsened and storage stability is maintained. If the melting point is below the upper limit, the target low-temperature fixability can be achieved by adding an appropriate amount of the crystalline polyester resin.

[0080] The acid value of the crystalline polyester resin is preferably 80 mgKOH / g or less from the viewpoint of ease of forming aggregated particles. If the acid value is higher than 80 mgKOH / g, the dispersion liquid becomes highly stable and aggregation becomes difficult. The acid value of the crystalline polyester resin is more preferably 75 mgKOH / g or less, and even more preferably 70 mgKOH / g or less.

[0081] The acid value of the crystalline polyester resin is measured by the method described in the Examples section below.

[0082] The toner base particles may contain only one type of crystalline polyester resin in the core, or may contain two or more types of resins with different monomer compositions, physical properties, and the like.

[0083] The crystalline polyester resin is preferably contained in a proportion of 3% by mass or more and 20% by mass or less relative to the total mass of the toner base particles. If the content of the crystalline polyester resin in the toner base particles is 3% by mass or more, a toner with excellent low-temperature fixability can be obtained. From this perspective, the content of the crystalline polyester resin in the toner base particles is particularly preferably 5% by mass or more, and even more preferably 8% by mass or more. On the other hand, if the content of the crystalline polyester resin in the toner base particles is 20% by mass or less, a toner with sufficient storage stability can be obtained. From this perspective, the content of the crystalline polyester resin in the toner base particles is particularly preferably 18% by mass or less, and even more preferably 15% by mass or less.

[0084] From the viewpoint of the balance between complex viscosity and residual rate, the content ratio of the amorphous polyester resin and the crystalline polyester resin constituting the core is preferably amorphous polyester resin:crystalline polyester resin (mass ratio) = 97:3 to 80:20, more preferably 95:5 to 85:15, and even more preferably 93:7 to 90:10, relative to a total of 100 parts by mass.

[0085] <Method of manufacturing polyester resin> The method for producing the crystalline polyester resin and the amorphous polyester resin is not particularly limited, and they can be produced using known methods for producing polyester resins. For example, a monomer mixture containing an acid component, an alcohol component, etc. is charged into a reaction vessel, heated to an elevated temperature, and an esterification reaction or an ester exchange reaction is carried out, followed by removal of the water or alcohol produced by the reaction. The polycondensation reaction is then carried out, during which the pressure inside the reaction vessel is gradually reduced, and the polycondensation is carried out while the alcohol component is distilled off under a vacuum of 150 mmHg (20 kPa) or less, preferably 15 mmHg (2 kPa) or less.

[0086] Catalysts used in the esterification reaction, transesterification reaction, and polycondensation include titanium-based catalysts, tin-based catalysts such as dibutyltin oxide, calcium acetate, calcium acetate hydrate, tin acetate, tin disulfide, tin oxide, and 2-ethylhexanetin, zinc acetate, antimony trioxide, and germanium dioxide. Of these, titanium-based catalysts are preferred because they make it easier to obtain polyester resins with reduced VOC total amounts (TVOC: Total Volatile Organic Compounds). From the viewpoint of environmental impact, it is also desirable to minimize heavy metal contamination originating from heavy metal catalysts used as catalysts for polyester resins. From this viewpoint, it is preferable to minimize the use of antimony, tin, and other heavy metal components when producing amorphous polyester resins and crystalline polyester resins.

[0087] Examples of titanium catalysts include titanium alkoxide compounds having an alkoxy group, titanium carboxylate compounds, titanyl carboxylate, titanyl carboxylate salts, and titanium chelate compounds. Examples of titanium alkoxide compounds having an alkoxy group include tetramethoxytitanium, tetraethoxytitanium, tetrapropoxytitanium, tetrabutoxytitanium, tetrapentoxytitanium, and tetraoctoxytitanium. Examples of titanium carboxylate compounds include titanium formate, titanium acetate, titanium propionate, titanium octanoate, titanium oxalate, titanium succinate, titanium maleate, titanium adipate, titanium sebacate, titanium hexanetricarboxylate, titanium isooctanetricarboxylate, titanium octanetetracarboxylate, titanium decanetetracarboxylate, titanium benzoate, titanium phthalate, titanium terephthalate, titanium isophthalate, titanium 1,3-naphthalenedicarboxylate, titanium 4,4-biphenyldicarboxylate, titanium 2,5-toluenedicarboxylate, titanium anthracenedicarboxylate, titanium trimellitate, titanium 2,4,6-naphthalenetricarboxylate, titanium pyromellitate, and titanium 2,3,4,6-naphthalenetetracarboxylate. Of these, titanium tetrabutoxide is preferred. The titanium catalyst may be used alone or in combination of two or more kinds.

[0088] <Coloring agent> The toner may contain a colorant. Any known colorant can be used as the colorant contained in the toner of the present invention. Specific examples of the colorant include carbon black, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa yellow, rhodamine dyes and pigments, chrome yellow, quinacridone dyes, benzidine yellow, rose bengal, triallylmethane dyes, monoazo dyes, disazo dyes, and condensed azo dyes and pigments, and any known dyes and pigments can be used alone or in combination. In the case of full-color toners, it is preferable to use monoazo-, disazo-, polyazo-, or condensed azo-based dyes and pigments for yellow, quinacridone- and / or monoazo-based dyes and pigments for magenta, phthalocyanine-based dyes and pigments for cyan, and carbon black for black. As a combination of toner sets, it is preferable that the magenta toner contains a quinacridone-based dyes and pigments and / or monoazo-based dyes and pigments, the black toner contains carbon black, the cyan toner contains a copper phthalocyanine-based dyes and pigments, and the yellow toner contains at least one dyes and pigments selected from monoazo-, disazo-, and condensed azo-based dyes and pigments. Specific examples of cyan include CI Pigment Blue 15:3 and CI Pigment Blue 15:4; examples of yellow include CI Pigment Yellow 74, CI Pigment Yellow 83, which is a disazo dye / pigment, and CI Pigment Yellow 93, CI Pigment Yellow 155, CI Pigment Yellow 180, and CI Pigment Yellow 185, which are condensed azo dye / pigment; and examples of magenta include CI Pigment Red 48:1, CI Pigment Red 53:1, CI Pigment Red 57:1, CI Pigment Red 5, CI Pigment Red 122 and CI Pigment Red 209, which are quinacridone dye / pigment, and CI Pigment Red 269(238), which is a monoazo dye / pigment.

[0089] The colorant is preferably used in an amount of 3 to 20% by mass relative to the total mass (100% by mass) of the toner base particles.

[0090] <Wax> The toner may further contain a wax, and by containing a wax, it is possible to improve low-temperature fixability and high-temperature offset property. The wax may be contained in any form in the toner, and for example, the wax may be present in a form in which the binder resin and the wax are partially or entirely compatible with each other, or the wax may be separated and encapsulated as a domain in the core, or the wax may be separated and encapsulated as a domain in the shell, or the wax may be present separated and encapsulated on the surface of the toner.

[0091] The type of wax contained in the present toner is not limited, but it is preferable that the toner contains an ester wax.

[0092] (ester wax) Examples of ester waxes include ester waxes having a long-chain aliphatic group, such as behenyl behenate, montanic acid ester, stearyl stearate, and erythritol tetrabehenate. Among these, monoester waxes containing primarily C18 and / or C22 hydrocarbons are more preferred, and among these, behenyl behenate, stearyl behenate, behenyl stearate, and those containing primarily these are particularly preferred from the viewpoints of low dust and low-temperature fixation. From the viewpoint of low dust, the number of carbon atoms in one molecule of the ester wax is preferably 36 or more, and more preferably 40 or more. On the other hand, from the viewpoint of low temperature fixation, the number of carbon atoms in one molecule of the ester wax is preferably 95 or less, more preferably 60 or less, even more preferably 48 or less, and particularly preferably 44 or less.

[0093] (Other waxes) The toner may contain other waxes in addition to the ester wax, or other waxes may be used in combination with the ester wax. Examples include olefin waxes such as low-molecular-weight polyethylene, low-molecular-weight polypropylene, and copolymerized polyethylene; paraffin wax; vegetable waxes such as hydrogenated castor oil and carnauba wax; ketones having a long-chain alkyl group such as distearyl ketone; silicones having an alkyl group; higher fatty acids such as stearic acid; higher fatty acid amides such as oleic acid amide and stearic acid amide; etc. Preferred examples include hydrocarbon waxes such as paraffin wax and Fischer-Tropsch wax; and silicone waxes.

[0094] (amount of wax) When the toner contains wax, the amount of wax contained in the toner is preferably 3 to 20% by mass, more preferably 5 to 10% by mass, relative to the total mass (100% by mass) of the toner base particles.

[0095] <Charge control agent> The present toner may contain a charge control agent to improve the charging characteristics of the toner. Any known charge control agent can be used. Specific examples of charge control agents include nigrosine dyes, amino group-containing vinyl copolymers, quaternary ammonium salt compounds, polyamine resins, etc. for positively chargeable agents, and metal-containing azo dyes containing metals such as chromium, zinc, iron, cobalt, and aluminum, as well as salts and metal complexes of salicylic acid or alkylsalicylic acid with the above-mentioned metals, etc. for negatively chargeable agents.

[0096] The amount of the charge control agent is preferably 0.1 to 25% by mass, more preferably 1 to 15% by mass, based on the total mass (100% by mass) of the toner. The charge control agent may be mixed inside the toner base particles, or may be attached to the surface of the toner base particles.

[0097] <External additives> The toner contains an external additive to improve the fluidity and charge controllability of the toner. The external additive is usually attached to the surface of the toner base particles, but the degree to which the external additive is embedded in the base particles may be in any state. That is, a part or all of the external additive may be attached so as to be in contact with the surface of the base particles, or may be embedded in the surface, and a part or all of the external additive may be present in a dispersed or aggregated state on the surface of the base particles. The particle size of the external additive particles is preferably such that the ratio (particle size of external additive particles) / (average particle size of toner base particles) is in the range of 0.1% to 5% of the average particle size of the toner base particles.

[0098] The external additive may be selected from various inorganic or organic fine particles and used in combination. Two or more types of external additives may also be used in combination.

[0099] Examples of inorganic fine particles that can be used include various carbides such as silicon carbide, boron carbide, titanium carbide, zirconium carbide, hafnium carbide, vanadium carbide, tantalum carbide, niobium carbide, tungsten carbide, chromium carbide, molybdenum carbide, and calcium carbide; various nitrides such as boron nitride, titanium nitride, and zirconium nitride; various borides such as zirconium boride; various oxides such as titanium oxide, calcium oxide, magnesium oxide, zinc oxide, copper oxide, aluminum oxide, cerium oxide, silica, and colloidal silica; various titanate compounds such as calcium titanate, magnesium titanate, and strontium titanate; phosphate compounds such as calcium phosphate; sulfides such as molybdenum disulfide; fluorides such as magnesium fluoride and carbon fluoride; various metal soaps such as aluminum stearate, calcium stearate, zinc stearate, and magnesium stearate; talc, bentonite, various carbon blacks, conductive carbon blacks, magnetite, and ferrite.

[0100] Examples of organic fine particles that can be used include fine particles of styrene-based resins, acrylic-based resins, epoxy-based resins, and melamine-based resins. Fluorine-containing fine particles can also be used to improve charging stability. Among these external additives, silica, titanium oxide, alumina, zinc oxide, various carbon blacks, and conductive carbon black are particularly preferred. Furthermore, the external additives used may include inorganic or organic fine particles whose surfaces have been subjected to a surface treatment, such as hydrophobic treatment, using a treatment agent, such as a silane coupling agent (e.g., hexamethyldisilazane (HMDS) or dimethyldichlorosilane (DMDS)), a titanate-based coupling agent, a silicone oil treatment agent (e.g., silicone oil, dimethylsilicone oil, modified silicone oil, or amino-modified silicone oil), a silicone varnish, a fluorine-based silane coupling agent, a fluorine-based silicone oil, or a coupling agent having an amino group or a quaternary ammonium base. Two or more of these treatment agents can also be used in combination.

[0101] The amount of the external additive added is preferably 1.0 part by mass or more, particularly preferably 1.5 parts by mass or more, and is preferably 6.5 parts by mass or less, particularly preferably 5.5 parts by mass or less, relative to 100 parts by mass of the toner base particles.

[0102] In the present toner, from the viewpoint of charge control, conductive fine particles may be used as an external additive. Examples of conductive fine particles include metal oxides such as conductive titanium oxide, silica, and magnetite, or those doped with a conductive substance, organic fine particles obtained by doping a polymer having conjugated double bonds such as polyacetylene, polyphenylacetylene, and poly-p-phenylene with a conductive substance such as a metal, and carbon such as carbon black and graphite. However, from the viewpoint of imparting conductivity without impairing the fluidity of the toner, conductive titanium oxide or those doped with a conductive substance are more preferred.

[0103] The content of the conductive fine particles is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, and particularly preferably 0.2 parts by mass or more, relative to 100 parts by mass of the toner base particles, and the upper limit of the content of the conductive fine particles is preferably 3 parts by mass or less, more preferably 2 parts by mass or less, and particularly preferably 1 part by mass or less.

[0104] <Toner complex viscosity> The complex viscosity of this toner at 110°C, measured at a measurement frequency of 6.28 rad / sec and a heating rate of 4°C / min, is preferably less than 900 Pa·s. With a complex viscosity at 110°C in this range, the toner will fuse quickly onto the medium when exposed to a specified temperature, providing sufficient low-temperature fixability, particularly when printing on film. From the viewpoint of low-temperature fixability, the complex viscosity of the toner at 110°C is preferably less than 900 Pa·s, more preferably less than 700 Pa·s, and even more preferably less than 500 Pa·s. On the other hand, from the viewpoint of storage stability, the complex viscosity at 110°C is preferably 200 Pa·s or more, and more preferably 300 Pa·s or more. The complex viscosity at 110°C can be measured by the method described in the Examples below.

[0105] As a method for adjusting the complex viscosity of the present toner to fall within the above-mentioned preferred range, for example, the following measures can be taken during the production of the present toner or in the component composition of the present toner. Examples of methods include reducing the molecular weight or crosslinking rate of the amorphous polyester resin, increasing the proportion of the core in the case of a core-shell toner, dispersing a crystalline polyester in the core, dispersing a wax with a low melting point in the core, or dispersing a plasticizer in the core.

[0106] <Sieve retention rate> When 20 g of the toner is placed in a thermo-hygrostat at a temperature of 50°C and a relative humidity of 40%, and is held for 20 hours, and then passed through a 60-mesh sieve, it is preferable that the remaining rate on the sieve is less than 10%, since this prevents blocking of toner particles during storage. From the viewpoint of storage stability, the residual rate of the present toner is preferably less than 10%, more preferably less than 5%, even more preferably less than 1%, and particularly preferably less than 0.5%. From the same viewpoint, it is most preferable that the residual rate is 0%, i.e., no toner remains on the sieve.

[0107] As a method for making the residual ratio of the present toner less than the above upper limit, for example, the following measures can be taken during the production of the present toner or in the component composition of the present toner. Examples of measures include increasing the molecular weight or crosslinking rate of the amorphous polyester, increasing the proportion of the shell in the case of a core-shell toner, selecting a crystalline polyester that separates from the amorphous polyester for the core at room temperature when dispersing the crystalline polyester in the core, dispersing a wax with a high melting point in the core, and increasing the amount of external additives.

[0108] <Form of this toner> From the viewpoint of image reproducibility and toner consumption, the volume median particle size (Dv50) of the present toner is preferably 7.0 μm or less, more preferably 6.5 μm or less, and even more preferably 6.3 μm or less. On the other hand, from the viewpoint of environmental safety with respect to dust, the volume median particle diameter (Dv50) of the present toner is preferably 3.0 μm or more, more preferably 4.0 μm or more, even more preferably 4.5 μm or more, even more preferably 5.0 μm or more, even more preferably 5.5 μm or more. In the present invention, the "volume median particle diameter (Dv50)" is measured by the method described in the Examples section below and is defined as the value measured in this manner, and is also defined as the value measured on toner particles finally obtained in the production process, which include toner base particles and, if necessary, external additives.

[0109] The shape of the toner has an average circularity of preferably 0.92 or more, more preferably 0.95 or more, and even more preferably 0.96 or more, as measured using a flow particle image analyzer FPIA-3000 (manufactured by Malvern Instruments), while the average circularity is preferably 0.99 or less, more preferably 0.98 or less, and even more preferably 0.97 or less.

[0110] [Toner manufacturing method] The present toner can be produced by producing the present toner base particles by a known method and externally adding an external additive to the present toner base particles.

[0111] <Method of manufacturing the toner base particles> A method can be used in which each raw material is prepared as particles smaller than the toner base particles, and these are mixed, aggregated, and aged to obtain toner base particles. For example, toner base particles can be obtained by mixing fine particles of binder resin and, if necessary, colorant particles, wax, charge control agent, etc., and aggregating and aging (thermal fusion), followed by filtering, washing, and drying. The binder resin fine particles can be obtained by polycondensing raw material monomers to obtain a binder resin, and then mixing and emulsifying the obtained binder resin with an aqueous medium. From the viewpoint that aggregating particles by an emulsion aggregation method performed in an aqueous system makes it easy to control the circularity of the final base particles, it is preferable to obtain the polyester resin fine particles as an aqueous emulsion by emulsification.

[0112] (A method in which the binder resin is obtained and then mixed with an aqueous medium to emulsify it) After obtaining a binder resin by any polymerization method, the binder resin is mixed with an aqueous medium and emulsified by applying shear force, whereby primary polymer particles of the binder resin can be obtained.

[0113] Examples of emulsifiers for applying shear force include homogenizers, homomixers, pressure kneaders, extruders, and media dispersers. If the viscosity of the binder resin during emulsification is high and the primary resin particles do not become small enough to reach the desired particle size, an emulsifier capable of pressurizing the resin to atmospheric pressure or higher can be used to raise the temperature to the higher of either the melting point or the glass transition temperature of the resin, thereby emulsifying the resin in a state where the viscosity of the resin is reduced, thereby obtaining primary particles of the desired particle size.

[0114] Another method for reducing the resin viscosity is to premix an organic solvent with the binder resin. The organic solvent used is not particularly limited as long as it dissolves the styrene-acrylic resin. Examples of suitable organic solvents include ketone-based solvents such as tetrahydrofuran (THF), methyl acetate, ethyl acetate, and methyl ethyl ketone, and benzene-based solvents such as benzene, toluene, and xylene. Furthermore, alcohol-based solvents such as ethanol and isopropyl alcohol may be added to the water or resin to improve compatibility with aqueous media and control particle size distribution. When an organic solvent is added, it must be removed from the emulsion after emulsification. Methods for removing the organic solvent include volatilizing the organic solvent at room temperature or under reduced pressure with heating.

[0115] For the purpose of controlling particle size distribution, salts such as sodium chloride and potassium chloride, ammonia, etc. may be added, and an emulsifier or dispersant may also be added. Examples of the emulsifier and dispersant used here include water-soluble polymers such as polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, and sodium polyacrylate; the emulsifiers mentioned above; and inorganic compounds such as tricalcium phosphate, aluminum hydroxide, calcium sulfate, calcium carbonate, and barium carbonate. The amount used is preferably 0.01 to 20 parts by mass per 100 parts by mass of the binder resin.

[0116] In addition to the above-mentioned methods, a phase inversion emulsification method may be used as a method for emulsifying a binder resin obtained by any polymerization method by mixing it with an aqueous medium. The phase inversion emulsification method involves adding an organic solvent, a neutralizing agent, and a dispersion stabilizer to the binder resin as needed, adding an aqueous medium dropwise under stirring to obtain emulsified particles, and then removing the organic solvent from the resin dispersion to obtain an emulsion. The organic solvent may be the same as the organic solvent described above. The neutralizing agent may be a common acid or alkali such as nitric acid, hydrochloric acid, sodium hydroxide, or ammonia.

[0117] (Particle size of primary polymer particles of binder resin) The median diameter (D50) of the polymer primary particles of the binder resin (hereinafter also referred to as resin primary particles) is preferably 100 nm or more, more preferably 150 nm or more, and even more preferably 180 nm or more, and is preferably 350 nm or less, more preferably 300 nm or less, and even more preferably 280 nm or less. The median diameter (D50) of the primary particles of the binder resin is measured by the method described in the Examples section below.

[0118] (Agglutination process) In the aggregation step, the resin primary particles, and if necessary, colorant particles, a charge control agent, wax, etc. are mixed simultaneously or sequentially. From the viewpoint of uniformity of composition and particle size, it is preferable to prepare dispersions of the respective components in advance, i.e., a resin primary particle dispersion, if necessary, a colorant particle dispersion, a charge control agent dispersion, and a wax microparticle dispersion, and then mix them to obtain a mixed dispersion.

[0119] When the toner base particles have a core-shell structure, the primary particles of the binder resin for the core and the primary particles of the binder resin for the shell may be charged at the same time, or some or all of the primary particles of the binder resin for the core may be aggregated with other components, and then the primary particles of the binder resin for the shell may be added.

[0120] When primary particles of a core binder resin (also referred to as a core component) and primary particles of a shell binder resin (also referred to as a shell component) are charged simultaneously, the shell component will spontaneously adhere to the periphery of the core component if the polarity of the shell component is designed so that it is thermodynamically intermediate between the polarity of the core component and that of the medium (for example, water). When the shell component is adhered in a wet medium such as water and / or an organic solvent, it is preferable to add the shell component after the composition of the raw material of the core component has been determined (when toner base particles are produced by aggregating particles smaller than the toner base particles, part or all of the core component has been aggregated), from the viewpoint of arranging the shell component more closely on the surface of the core component.

[0121] The shell component may be added once or multiple times. The shell component added in the first addition may be different from the shell component added in the subsequent additions, and any combination may be used. In order to increase the stability of the core-shell structured particle aggregates obtained in the aggregation step, it is preferable to fuse the aggregated particles in the aging step after the aggregation step.

[0122] The colorant particles are preferably used in a state dispersed in water in the presence of an emulsifier, and the volume average particle size of the colorant particles is preferably 0.01 μm or more, particularly preferably 0.05 μm or more, and preferably 3 μm or less, particularly preferably 1 μm or less.

[0123] In the aggregation step, aggregation is usually carried out in a tank equipped with a stirring device, and there are methods of aggregation by heating, aggregation by adding an electrolyte, and a combination of these methods.

[0124] When an electrolyte is added to perform aggregation, the electrolyte may be any of an acid, alkali, or salt, and may be either organic or inorganic, but specific examples include acids such as hydrochloric acid, nitric acid, sulfuric acid, citric acid, etc.; alkalis such as sodium hydroxide, potassium hydroxide, aqueous ammonia, etc.; and salts such as NaCl, KCl, LiCl, Na2SO4, K2SO4, Li2SO4, MgCl2, CaCl2, MgSO4, CaSO4, ZnSO4, Al2(SO4)3, Fe2(SO4)3, CH3COONa, CH5SO3Na, etc. Among these, inorganic salts having a divalent or higher polyvalent metal cation are preferred.

[0125] The amount of electrolyte added varies depending on the type of electrolyte, the target particle size, etc., but is preferably 0.02 parts by mass or more, more preferably 0.05 parts by mass or more, relative to 100 parts by mass of the solid components of the mixed dispersion, and is preferably 25 parts by mass or less, more preferably 15 parts by mass or less, and particularly preferably 10 parts by mass or less. When aggregation is carried out by adding an electrolyte, the aggregation temperature is preferably 20°C or higher, particularly preferably 30°C or higher, and preferably 70°C or lower, particularly preferably 60°C or lower.

[0126] The time required for aggregation is optimized depending on the shape of the apparatus and the processing scale, but in order for the particle size of the toner base particles to reach the target particle size, it is preferable to maintain the temperature at the above-mentioned predetermined temperature for at least 30 minutes. The temperature may be increased at a constant rate or increased in stages until the predetermined temperature is reached.

[0127] (ripening process) In the aging step, the mixed dispersion obtained in the aggregation step is heated under sufficient stirring conditions. In the case of a core-shell structure, the temperature in the aging step is preferably equal to or higher than the Tg of the primary particles of the shell binder resin, more preferably equal to or higher than the Tg of the primary particles of the shell binder resin by 5° C. The time required for the aging step varies depending on the shape of the target toner base particles, but it is desirable to maintain the temperature for preferably 0.1 to 10 hours, particularly preferably 0.5 to 5 hours, after the temperature reaches equal to or higher than the Tg of the primary particles of the shell binder resin.

[0128] After the aggregation step, preferably before or during the aging step, it is preferable to add a surfactant, adjust the pH, or use both. The surfactant used here can be one or more selected from emulsifiers that can be used in producing primary particles of a resin, and it is particularly preferable to use the same emulsifier as that used in producing the primary particles.

[0129] The amount of surfactant to be added is not limited, but is preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, and is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 10 parts by mass, relative to 100 parts by mass of the solid components of the mixed dispersion. The following is the result.

[0130] By adding a surfactant or adjusting the pH after the aggregation step and before the completion of the aging step, it is possible to suppress aggregation of the particle aggregates obtained in the aggregation step, and in some cases it is possible to suppress the generation of coarse particles in the aging step.

[0131] By controlling the time of the aging process, it is possible to produce toner base particles of various shapes depending on the purpose, such as grape-shaped particles in which the aggregated shape of the polymer primary particles is maintained, potato-shaped particles in which fusion has progressed, and spherical particles in which fusion has progressed even further.

[0132] <Method of adding external additives> Examples of methods for adding external additives include a method using a high-speed mixer such as a Henschel mixer, and a method using a device capable of applying compressive shear stress. The toner can be produced by a one-stage external addition method in which all external additives are added to the toner base particles at the same time, or by a separate-stage external addition method in which the external additives are added separately. To prevent the temperature from rising during the external addition, a cooling device may be installed in the vessel, or external addition may be carried out in stages.

[0133] [Usage form] The present toner may be used in either the form of a two-component developer in which a toner is used together with a carrier, or a magnetic or non-magnetic one-component developer in which no carrier is used. When used as a two-component developer, the carrier may be a magnetic substance such as iron powder, magnetite powder, ferrite powder, or the like, or a known substance such as a magnetic carrier or a resin-coated magnetic substance. The coating resin of the resin-coated carrier may be a commonly known styrene resin, acrylic resin, styrene-acrylic copolymer resin, silicone resin, modified silicone resin, fluororesin, or a mixture thereof.

[0134] [Cartridges and image forming devices] Next, an embodiment of an image forming apparatus using the toner (image forming apparatus of the present invention) will be described. However, the embodiment is not limited to the following description, and can be modified as desired without departing from the gist of the present invention.

[0135] The image forming apparatus is configured to include an electrophotographic photosensitive member, a charging device, an exposure device, a developing device, and a toner, and may further include a transfer device, a cleaning device, and a fixing device as required.

[0136] The electrophotographic photosensitive member is not particularly limited, but for example, a drum-shaped photosensitive member having the above-described photosensitive layer formed on the surface of a cylindrical conductive support can be used. The charging device is a device for uniformly charging the surface of the electrophotographic photosensitive member to a predetermined potential. Typical charging devices include non-contact corona charging devices such as corotrons and scorotrons, and contact charging devices.

[0137] The type of the exposure device is not particularly limited as long as it can expose an electrophotographic photosensitive member to light to form an electrostatic latent image on the photosensitive surface of the electrophotographic photosensitive member. The transfer device applies a predetermined voltage (transfer voltage) with a polarity opposite to the charged potential of the toner, and transfers the toner image formed on the electrophotographic photosensitive member onto recording paper (paper, medium). There are no particular limitations on the type of transfer device, and any device using any method, such as corona transfer or roller transfer, can be used. The cleaning device scrapes off residual toner adhering to the electrophotographic photosensitive member with a cleaning member and collects the residual toner. However, if there is little or almost no toner remaining on the surface of the electrophotographic photosensitive member, a cleaning device may not be necessary. There are no particular restrictions on the cleaning device, and any cleaning device such as a brush cleaner, a magnetic roller cleaner, or a blade cleaner can be used.

[0138] In the image forming apparatus configured as above, an image is recorded as follows.

[0139] First, the surface (photosensitive surface) of the electrophotographic photoreceptor is charged to a predetermined potential by a charging device. At this time, charging may be performed by a DC voltage or by superimposing an AC voltage on the DC voltage. Next, the charged photosensitive surface of the electrophotographic photoreceptor is exposed by an exposure device in accordance with the image to be recorded, forming an electrostatic latent image on the photosensitive surface, and then the electrostatic latent image formed on the photosensitive surface of the electrophotographic photoreceptor is developed by a development device. The developing device forms a thin layer of toner using a regulating member such as a developing blade, frictionally charges the toner to a predetermined polarity, and transports the toner while carrying it on a developing roller, bringing it into contact with the surface of an electrophotographic photosensitive member.

[0140] When the charged toner carried on the developing roller comes into contact with the surface of the electrophotographic photosensitive member, a toner image corresponding to the electrostatic latent image is formed on the photosensitive surface of the electrophotographic photosensitive member. This toner image is then transferred onto recording paper or the like by a transfer device. After this, toner that has not been transferred and remains on the photosensitive surface of the electrophotographic photosensitive member is removed by a cleaning device. After the toner image is transferred to a printing medium such as recording paper, the toner image is passed through a fixing device to be thermally fixed to the printing medium such as recording paper, thereby obtaining a final image. In addition to the above-described configuration, the image forming apparatus may be configured to be capable of performing, for example, a charge removal process. The charge removal process is a process of removing charge from an electrophotographic photosensitive member by exposing the electrophotographic photosensitive member to light.

[0141] Furthermore, the image forming apparatus may be further modified and configured, for example, to be capable of performing processes such as a pre-exposure process and an auxiliary charging process, to be configured to perform offset printing, or to be configured as a full-color tandem system using multiple types of toner.

[0142] In addition, a member for storing toner may be combined with one or more of a charging device, an exposure device, a developing device, a transfer device, a cleaning device, and a fixing device to form an integrated cartridge (hereinafter referred to as a "toner cartridge" as appropriate), and this toner cartridge may be configured to be detachable from the main body of an image forming device such as a copier or laser beam printer. The toner is applied to this toner cartridge to constitute the toner cartridge of the present invention.

[0143] [Print media] There are no particular restrictions on the printing media that can be printed on using this toner, and any media commonly used in image forming devices can be used, including general printing paper (including cardboard, postcards, envelopes, plain paper, thin paper, etc.), resin (plastic) such as PET or metal coated paper, OHP sheets, OHP film, tracing paper, etc. In particular, since the toner has excellent low-temperature fixability, it is effective when the printing medium is a plastic film, which requires even higher low-temperature fixability. [Example]

[0144] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to the following examples as long as the gist of the present invention is not exceeded. In the following examples and comparative examples, "parts" simply means "parts by mass." Furthermore, the unit "%" in solid content concentration and aqueous solution concentration means "% by mass."

[0145] The methods for measuring various physical properties are as follows.

[0146] <Medium diameter (D50)> The median diameter (D50) of particles with a median diameter of less than 1 micron was measured using a Microtrac Nanotrac 150 (hereinafter referred to as Nanotrac) manufactured by Nikkiso Co., Ltd. and the company's analysis software, Microtrac Particle Analyzer Ver. 10.1.2-0.19EE. The measurement was performed using ion-exchanged water with an electrical conductivity of 0.5 μS / cm as the solvent, with a solvent refractive index of 1.333, a measurement time of 120 seconds, and five measurements, according to the method described in the instruction manual, and the average value was calculated. Other setting conditions were particle refractive index of 1.59, transparency, shape: spherical, and density: 1.04.

[0147] <Volume median particle size (Dv50)> The volume median particle size (Dv50) of particles with a volume median particle size (Dv50) of 1 micron or greater was measured using a Beckman Coulter Multisizer III (aperture diameter: 100 μm or less, abbreviated as Multisizer). The particles were dispersed in Beckman Coulter's Isoton II as the dispersion medium, with the dispersoid concentration set to 0.03% by mass.

[0148] <Average circularity> The average circularity was measured by dispersing the dispersoid in a dispersion medium (Celsius, manufactured by Malvern Instruments) to a concentration of 5720 to 7140 particles / μL, and using a flow particle analyzer (FPIA3000, manufactured by Malvern Instruments) in HPF mode under conditions of an HPF analysis volume of 0.35 μL and an HPF detection volume of 2,000 to 2,500 particles.

[0149] <Mass average molecular weight (Mw)> The Mw of the polyester resin was determined by the GPC method from the retention time corresponding to the peak value of the elution curve obtained, in terms of standard styrene. Equipment: Tosoh GPC equipment HLC-8320 Column: TOSOH TSKgel SuperHM-H (diameter 6 m x length 150 mm x 2) Solvent: THF Column temperature: 40℃ Flow rate: 1mL / min Sample concentration: 4mg / 10mg Calibration curve: Standard polystyrene

[0150] <Emulsion solids concentration> The solid content concentration of the emulsion was determined by heating a 2 g sample at 195°C for 90 minutes to evaporate the water using an infrared moisture meter FD-610 manufactured by Kett Electric Laboratory.

[0151] <Glass transition temperature (Tg)> The glass transition temperature of the amorphous polyester resin was measured using a differential scanning calorimeter (Shimadzu Corporation, "DSC-60") from the intersection of the baseline of the chart and the tangent to the endothermic curve at a heating rate of 5°C / min. 10 mg ± 0.5 mg of the sample was weighed into an aluminum pan, melted at 100°C (above the glass transition temperature) for 10 minutes, and then rapidly cooled using dry ice.

[0152] <Softening temperature (T4)> The softening temperature of the polyester resin was measured using a flow tester (Shimadzu Corporation, "CFT-500D") with a 1 mm diameter x 10 mm nozzle, a load of 294 N, and a uniform temperature increase rate of 3°C / min, at which the temperature at which half of a 1.0 g resin sample flowed out was measured, and this was taken as the softening temperature.

[0153] <Melting point (Tm)> The melting point of the crystalline polyester resin was measured using a differential scanning calorimeter (Shimadzu Corporation, "DSC-60"), and the temperature of the endothermic peak with the largest peak area was taken as the melting point at a heating rate of 5°C / min. 10 mg ± 0.5 mg of the sample was weighed into an aluminum pan, melted at 100°C (above the glass transition temperature) for 10 minutes, and then rapidly cooled using dry ice.

[0154] <Acid value> The acid value of the polyester resin was measured as follows. Approximately 0.2 g of the sample to be measured was accurately weighed into a sidearm Erlenmeyer flask (a(g)), 20 mL of benzyl alcohol was added, and the mixture was heated in a nitrogen atmosphere using a heater at 230°C for 15 minutes to dissolve the sample. After cooling to room temperature, 20 mL of chloroform and a few drops of cresol red solution were added, and the mixture was titrated with 0.02 N KOH solution (titer = b (mL), titer of KOH solution = p). A blank measurement was performed in the same manner (titer = c (mL)), and the acid value was calculated according to the following formula. Acid value (mgKOH / g)={(bc)×0.02×56.11×p} / a

[0155] <Calculation of Hansen melting ball for polyester resin> The Hansen Solubility Sphere of the polyester resin was calculated using the solubility parameter calculation software HSPiP (Hansen Solubility Parameters in Practice 5th Edition 5.4.08 (available from https: / / www.hansen-solubility.com / HSPiP / )). The detailed calculation method will be explained below. The Hansen Sphere can be calculated using the "Sphere" software program. Select any solvent group and enter the results of the resin's solubility test (described below) in each solvent into a table. The evaluation results are assigned a score of 1, 2, 3, 4, 5, and 6, with insoluble solvents being assigned a score of "0" and soluble solvents being assigned a score of "1 to 6" (1 being the most soluble and 6 being the least soluble). After entering the scores in the table, check the "Genetic Algorithm" fitting method and click the "Calculate the Best HSP" button to calculate the Hansen Sphere. The Hansen Sphere is numerically expressed using three-dimensional coordinates (δP, δD, δH) consisting of polarity, dispersion, and hydrogen bonding terms, and a radius R.

[0156] <Solubility test> The solubility test for calculating the Hansen Solubility Ball can be performed using the following method. Depending on the form of the resin, crush the solid resin into small pieces using a mortar or scissors, measure out 0.05 parts, and place it in a vial. Add 1.0 part of any solvent to this, seal with a lid, and let it stand at room temperature for 24 hours. After leaving it, observe the sample and give it a score according to the following evaluation criteria. 0: No dissolution at all, and no swelling of the resin is observed 1: Completely dissolved, no cloudy liquid 2: 90% or more by mass of the resin is dissolved, or the resin is completely dissolved but the liquid is cloudy 3: 80% or more but less than 90% by mass of the resin dissolves 4: 50% or more but less than 80% of the resin dissolves 5: 20% by mass or more but less than 50% by mass of the resin dissolves 6: Less than 20% by mass of the resin is dissolved, or the resin is not dissolved but is swollen

[0157] <Calculating the overlap volume of Hansen melting spheres> For two or more Hansen melting spheres, it is possible to calculate the overlapping volume of the spheres. Consider the case of two melting spheres (say, melting sphere 1 and melting sphere 2), (1) When melting ball 1 and melting ball 2 do not overlap at all, (2) When one of the molten spheres is completely contained within the other molten sphere, (3) When dissolving sphere 1 and dissolving sphere 2 have both parts that share volume and parts that do not, i.e., when dissolving sphere 1 and dissolving sphere 2 partially overlap, The cases can be divided into three patterns: (1) the overlapping volume is zero, (2) the overlapping volume is equal to the volume of the enclosed molten sphere, and (3) it is the volume of the overlapping part of each molten sphere.

[0158] A more detailed calculation method for cases (2) and (3) is as follows.

[0159] ((2) When one of the molten spheres is completely contained within the other molten sphere) Let the radius of dissolving sphere 1 be R1 and the radius of dissolving sphere 2 be R2. In this case, the volume of the smaller sphere is the volume of the overlapping part. If the smaller dissolving sphere is dissolving sphere 1 and the larger dissolving sphere is dissolving sphere 2, the volume of the overlapping part is V = 4 / 3π × R1 3 This becomes:

[0160] ((3) When two melting spheres partially overlap) In this case, it is possible to calculate the volume V of the entire overlapping area by calculating the volumes V1 and V2 cut out in the overlapping parts of each sphere and adding them together. Let R1 be the radius of melting sphere 1, R2 be the radius of melting sphere 2, and D be the distance between the centers of the overlapping melting spheres 1 and 2. V1=(π×(R1+R2-D) 2 ×(D 2 +2×D×R2-3×R1 2 +2×R2×R1+2×R2 2 )) / (12×D) V2=(π×(R1+R2-D) 2 ×(D 2+2×D×R1-3×R2 2 +2×R1×R2+2×R1 2 )) / (12×D) V=V1+V2

[0161] Next, the pigment dispersion, polymer primary particle dispersion, amorphous polyester resin dispersion, and crystalline polyester resin dispersion used in the examples and comparative examples will be described.

[0162] <Pigment dispersion G1> A pigment premix was prepared by pre-dispersing 20 parts of carbon black (Regal 330R, manufactured by Cabot Specialty Chemicals, Inc.), 1 part of a 20% aqueous solution of sodium dodecylbenzenesulfonate (hereinafter referred to as "20% DBS aqueous solution"), 4 parts of a nonionic surfactant (Emulgen 120, manufactured by Kao Corporation), and 75 parts of ion-exchanged water with a conductivity of 2 μS / cm in a propeller-equipped mixer vessel. This premix was then fed as a raw material slurry into a wet bead mill for dispersion. The wet bead mill's stator had an inner diameter of 120 mm and a separator diameter of 60 mm. Zirconia beads with a diameter of 0.1 mm were used as dispersion media. The effective internal volume of the stator was approximately 2 liters, and the media filling volume was 1.4 liters, resulting in a media filling rate of 70%. The rotor rotation speed was kept constant (the peripheral speed of the rotor tip was approximately 11 m / sec), and the raw material slurry was supplied from the supply port at a supply rate of approximately 40 liters / hr using a non-pulsating metering pump.When the predetermined particle size was reached, dispersion was stopped, and pigment dispersion G1 was obtained from the discharge port. During operation, cooling water at about 10° C. was circulated from the jacket. The median diameter (D50) of the dispersed pigment was 157 nm, and the pigment solids concentration was 24.6%.

[0163] <Amorphous polyester resin> Amorphous polyester resins A and B were produced as follows. A polycarboxylic acid component, a polyhydric alcohol component, and a polymerization catalyst were charged into a reaction vessel equipped with a distillation column, with the charge compositions shown in Table 1. The amount of the polymerization catalyst is the amount (ppm) relative to the polycarboxylic acid component. Next, the rotation speed of the stirring blade in the reaction vessel was maintained at 120 rpm, and the temperature was started to rise until the temperature in the reaction system reached 265°C, and the esterification reaction was carried out by maintaining this temperature. After the distillation of water from the reaction system ceased and the esterification reaction was completed, the temperature in the reaction system was lowered to 240°C, and the pressure in the reaction vessel was reduced over approximately 40 minutes to a vacuum degree of 133 Pa, and a polycondensation reaction was carried out while distilling the alcohol component from the reaction system. The viscosity of the reaction system increased with the reaction, and the degree of vacuum was increased as the viscosity increased, and the condensation reaction was carried out until the torque of the stirring blade reached a value indicating the desired softening temperature. When the predetermined torque was reached, the stirring was stopped, the reaction system was returned to normal pressure, and pressurized with nitrogen to remove (discharge) the reaction product from the reaction vessel, thereby obtaining each amorphous polyester resin. The physical properties (glass transition temperature, softening temperature, mass average molecular weight, acid value) of the obtained amorphous polyester resins A and B were measured. The results are shown in Table 1. The Hansen solubility parameter of the obtained amorphous polyester resin B is also shown in Table 1. The results of the solubility tests carried out to calculate the Hansen solubility parameters are shown in Tables 3A to 3C.

[0164] [Table 1]

[0165] <Amorphous polyester resin dispersion P1> 25 parts of amorphous polyester resin A was dissolved in 75 parts of methyl ethyl ketone (MEK), and 0.437 g of dimethylaminoethanol was added thereto, followed by stirring uniformly with a stirrer to prepare a resin solution. Next, 100 parts of demineralized water was placed in a round-bottom flask, and the prepared resin solution was further added thereto, followed by dispersion with a homogenizer (T25 model, manufactured by IKA) at a rotation speed of 8,000 rpm for 10 minutes. Thereafter, the solvent was removed by distillation under reduced pressure at 80°C using an aspirator, to obtain amorphous polyester resin dispersion P1. The median diameter (D50) of the amorphous polyester resin particles in amorphous polyester resin dispersion P1 was measured using a Nanotrac and was found to be 180 nm.

[0166] <Amorphous polyester resin dispersion P2> 25 parts of amorphous polyester resin B was dissolved in 75 parts of methyl ethyl ketone (MEK), and 0.376 g of dimethylaminoethanol was added thereto, followed by stirring uniformly with a stirrer to prepare a resin solution. Next, 100 parts of demineralized water was placed in a round-bottom flask, and the prepared resin solution was further added thereto, followed by dispersion with a homogenizer (T25 model, manufactured by IKA) at a rotation speed of 8,000 rpm for 10 minutes. Thereafter, the solvent was removed by vacuum distillation at 80°C using an aspirator to obtain amorphous polyester resin dispersion P2. The median diameter (D50) of the amorphous polyester resin particles in amorphous polyester resin dispersion P2 was measured using Nanotrac and was found to be 190 nm.

[0167] <Crystalline polyester resin> Crystalline polyester resins A, B, C, D, and E were produced as follows. A polycarboxylic acid component, a polyhydric alcohol component, and a polymerization catalyst were charged into a reaction vessel equipped with a distillation column, with the charging compositions shown in Table 2. The amount of the polymerization catalyst is the amount (ppm) relative to the polycarboxylic acid component. Next, the rotation speed of the stirring blade in the reaction vessel was maintained at 120 rpm, and the temperature was started to rise until the temperature in the reaction system reached 265°C, and the esterification reaction was carried out by maintaining this temperature. After the distillation of water from the reaction system ceased and the esterification reaction was completed, the temperature in the reaction system was lowered to 240°C, and the pressure in the reaction vessel was reduced over approximately 40 minutes to a vacuum degree of 133 Pa, and a polycondensation reaction was carried out while distilling the alcohol component from the reaction system. The viscosity of the reaction system increased with the reaction, and the degree of vacuum was increased as the viscosity increased, and the condensation reaction was carried out until the torque of the stirring blade reached a value indicating the desired softening temperature. Then, when the predetermined torque was reached, the stirring was stopped, the reaction system was returned to normal pressure, and pressurized with nitrogen to remove (discharge) the reaction product from the reaction vessel, and each crystalline polyester resin was obtained. The physical properties (melting point, acid value) of the obtained crystalline polyester resins A, B, C, D, and E were measured. The results are shown in Table 2. The Hansen solubility parameters of the obtained crystalline polyester resins A, B, C, D, and E are also shown in Table 2. The results of the solubility tests conducted to calculate the Hansen solubility parameters are shown in Tables 3A to 3C.

[0168] [Table 2]

[0169] <Crystalline polyester resin dispersion C1> 54 parts of crystalline polyester resin A was dissolved in 306 parts of chloroform, and 9.0 parts of a 20% DBS aqueous solution and 531 parts of demineralized water were added. This mixture was premixed in a homomixer for 3 minutes at 5,200 rpm, and then dispersed in one pass at 20,000 psi using a high-pressure homogenizer (Microfluidizer, manufactured by Powrex Corporation). Thereafter, the solvent was removed by vacuum distillation at 80°C using an aspirator to obtain crystalline polyester resin dispersion C1. The median diameter (D50) of the crystalline polyester resin particles in crystalline polyester resin dispersion C1 was measured using a Nanotrac and was found to be 185 nm.

[0170] <Crystalline polyester resin dispersion C2> 54 parts of crystalline polyester resin B was dissolved in 306 parts of chloroform, and 9.0 parts of a 20% DBS aqueous solution and 531 parts of demineralized water were added. This mixture was premixed in a homomixer for 3 minutes at 5,200 rpm, and then dispersed in one pass at 20,000 psi using a high-pressure homogenizer (Microfluidizer, manufactured by Powrex Corporation). Thereafter, the solvent was removed by vacuum distillation at 80°C using an aspirator to obtain crystalline polyester resin dispersion C2. The median diameter (D50) of the crystalline polyester resin particles in crystalline polyester resin dispersion C2 was measured using Nanotrac and was found to be 180 nm.

[0171] <Crystalline polyester resin dispersion C3> 54 parts of crystalline polyester resin C was dissolved in 306 parts of chloroform, and 9.0 parts of a 20% DBS aqueous solution and 531 parts of demineralized water were added. This mixture was premixed in a homomixer for 3 minutes at 5,200 rpm, and then dispersed in one pass at 20,000 psi using a high-pressure homogenizer (Microfluidizer, manufactured by Powrex Corporation). Thereafter, the solvent was removed by vacuum distillation at 80°C using an aspirator to obtain crystalline polyester resin dispersion C3. The median diameter (D50) of the crystalline polyester resin particles in crystalline polyester resin dispersion C3 was measured using a Nanotrac and was found to be 191 nm.

[0172] <Crystalline polyester resin dispersion C4> 54 parts of crystalline polyester resin D was dissolved in 306 parts of chloroform, and 9.0 parts of a 20% DBS aqueous solution and 531 parts of demineralized water were added. This mixture was premixed in a homomixer for 3 minutes at 5,200 rpm, and then dispersed in one pass at 20,000 psi using a high-pressure homogenizer (Microfluidizer, manufactured by Powrex Corporation). Thereafter, the solvent was removed by vacuum distillation at 80°C using an aspirator to obtain crystalline polyester resin dispersion C4. The median diameter (D50) of the crystalline polyester resin particles in crystalline polyester resin dispersion C4 was measured using a Nanotrac and was found to be 184 nm.

[0173] <Crystalline polyester resin dispersion C5> 54 parts of crystalline polyester resin E was dissolved in 306 parts of chloroform, and 9.0 parts of a 20% DBS aqueous solution and 531 parts of demineralized water were added. This mixture was premixed in a homomixer for 3 minutes at 5,200 rpm, and then dispersed in one pass at 20,000 psi using a high-pressure homogenizer (Microfluidizer, manufactured by Powrex Corporation). Thereafter, the solvent was removed by vacuum distillation at 80°C using an aspirator to obtain crystalline polyester resin dispersion C5. The median diameter (D50) of the crystalline polyester resin particles in crystalline polyester resin dispersion C5 was measured using Nanotrac and was found to be 188 nm.

[0174] In the following Tables 3A to 3C, the abbreviations for each solvent are as follows: THF: tetrahydrofuran TOL: Toluene HEX: Hexane BuOH: 1-butanol Ace: Acetone MEK: Methyl ethyl ketone MIBK: Methyl isobutyl ketone BzOH: benzyl alcohol MAC: Methyl acetate EAC: Ethyl acetate BuAC: n-butyl acetate PhF: Fluorobenzene CLF: chloroform ChBz: chlorobenzene BrNAPH: 1-bromonaphthalene VAM: vinyl acetate monomer GBI: gamma-butyrolactone DMC: Dimethyl carbonate Py: pyridine NMP: N-methyl-2-pyrrolidone DMF: N,N-dimethylformamide DMSO: dimethyl sulfoxide FA: Formic acid

[0175] [Table 3]

[0176] [Example 1] Toner T1 was prepared as follows.

[0177] A mixer equipped with a stirrer, a heating / cooling device, and a raw material / auxiliary feeder was charged with the following: amorphous polyester resin dispersion P2 (75 parts solids), 20% DBS aqueous solution (0.05 parts solids), crystalline polyester resin dispersion C2 (10 parts solids), 135 parts demineralized water, 10% magnesium sulfate heptahydrate aqueous solution (3.047 parts solids), 1% aluminum sulfate aqueous solution (0.082 parts solids), and pigment dispersion G1 (5 parts solids). The internal temperature was raised to 34.0°C over 40 minutes, and then to 37.0°C over 90 minutes. The volume median particle size (Dv50) was measured using a Multisizer and found to be 5.50 μm. Next, a mixture of 10 parts of amorphous polyester resin dispersion P1 for the shell and 0.2 parts of a 20% DBS aqueous solution (2 parts solids per 100 parts of polyester) was added dropwise over 30 minutes. 30 minutes after the dropwise addition was complete, 232 parts of demineralized water and 5.0 parts of a 10% EDTA aqueous solution were added. The pH of the system was adjusted to 8.4 using a 4.8% potassium hydroxide aqueous solution, and the temperature was raised to 63°C over 90 minutes, and then to 67°C over 60 minutes. The mixture was then cooled to 30°C over 30 minutes.

[0178] The resulting dispersion was extracted and filtered using a No. 5C filter paper manufactured by Toyo Roshi Kaisha, Ltd., under suction with an aspirator. The cake remaining on the filter paper was transferred to a stainless steel container equipped with a stirrer (propeller blade), and ion-exchanged water with an electrical conductivity of 1 μS / cm was added and stirred to uniformly disperse the mixture. This process was repeated until the electrical conductivity of the filtrate reached 2 μS / cm. The resulting cake was then dried for 48 hours in a fan dryer set at 30°C, yielding toner base particles B1.

[0179] To the toner base particles B1 (100 parts) prepared in this manner, 1.5 parts of large particle silica RX50 (manufactured by Nippon Aerosil Co., Ltd.), 2.0 parts of large particle silica NAX50 (manufactured by Nippon Aerosil Co., Ltd.), and 0.6 parts of small particle silica R812 (manufactured by Nippon Aerosil Co., Ltd.) were added, and the mixture was stirred and mixed in a Henschel mixer at 5000 rpm for 1 minute, and then sieved to obtain toner T1. The core / shell structure of this toner T1 is as shown in Table 4. The volume median particle size (Dv50) and average circularity of the obtained toner T1 were measured. The results are shown in Table 5. The toner T1 obtained in Example 1 does not contain bisphenol A derivatives, trimellitic anhydride components, antimony, or tin in its manufacturing process, and therefore does not contain these components. The same applies to the toners T2 and T3 in Examples 2 and 3 described below.

[0180] [Example 2] Toner T2 was prepared in the same manner as Toner T1 in Example 1, except that the crystalline polyester resin dispersion C2 was changed to crystalline polyester C3. The core / shell structure of this toner T2 is as shown in Table 4. The volume median particle diameter (Dv50) and average circularity of the obtained toner T2 were measured. The results are shown in Table 5.

[0181] [Example 3] Toner T3 was prepared in the same manner as toner T1 in Example 1, except that crystalline polyester resin dispersion C2 was replaced with crystalline polyester resin C4. The core / shell structure of this toner T3 is as shown in Table 4. The volume median particle diameter (Dv50) and average circularity of the obtained toner T3 were measured. The results are shown in Table 5.

[0182] [Comparative Example 1] Toner T4 was prepared in the same manner as toner T1 in Example 1, except that crystalline polyester resin dispersion C2 was replaced with crystalline polyester C1. The core / shell structure of this toner T4 is as shown in Table 4. The volume median particle diameter (Dv50) and average circularity of the obtained toner T4 were measured. The results are shown in Table 5.

[0183] Comparative Example 2 Toner T5 was prepared in the same manner as toner T1 in Example 1, except that crystalline polyester resin dispersion C2 was replaced with crystalline polyester C5. The core / shell structure of this toner T5 is as shown in Table 4. The volume median particle diameter (Dv50) and average circularity of the obtained toner T5 were measured. The results are shown in Table 5.

[0184] [Table 4]

[0185] [Table 5]

[0186] <Overlap volume of melting spheres V> The overlap volume V of the Hansen melting spheres of the amorphous polyester resin core and the crystalline polyester resin was calculated using the method described above. The data for each Hansen melting sphere used in the calculation is shown in Tables 1 and 2. Table 6 shows the overlap volume V of the Hansen melting spheres of the amorphous polyester resin and crystalline polyester resin cores contained in the toners of the examples and comparative examples.

[0187] <(V·X) / 100> The value of (V·X) / 100 was calculated by multiplying the volume V of the overlapping area of ​​the Hansen melting spheres of the amorphous polyester resin and crystalline polyester resin in the core by the content X (mass%) of crystalline polyester resin in the toner base particles and dividing the result by 100. (V·X) / 100 is shown in Table 6.

[0188] <Complex viscosity> The complex viscosity was measured using a rheometer ARES manufactured by TA Instruments as follows. Approximately 1.3 g of the toner sample was placed in a 25 mm diameter jig and pressed for 10 minutes with a 30 kg load using a press heated to 50°C to form a pellet. The resulting pellet was placed in a measuring device equipped with circular parallel plates with a diameter of 25 mm, and the upper plate was lowered while the temperature was raised to 120°C to adjust the thickness of the pellet to 3.0 to 3.5 mm. After that, the temperature was lowered, and the measurement frequency was set to 6.28 rad / s, the initial temperature to 40°C, the delay time before measurement to 3 minutes, the automatic tension adjustment (pulling direction, initial force is 0, automatic tension sensitivity is 2.0 g, automatic tension switching elastic modulus is 1.0 × 10 8 The measurements were performed under the conditions of: (Pa), final temperature 150°C, heating rate 4°C / min, measurement cycle time 1 min, initial strain 0.1%, and automatic strain adjustment. The complex viscosity value at 110°C was calculated by reading the complex viscosity value at each point on a graph created from the obtained data. The complex viscosity was evaluated according to the following criteria. Table 6 shows the complex viscosity and evaluation results of each toner. (Evaluation criteria) 〇: Complex viscosity at 110℃ is less than 500 Pa·s △: Complex viscosity at 110°C is 500 Pa·s or more but less than 900 Pa·s ×: Complex viscosity at 110°C is 900 Pa·s or more

[0189] <Sieve retention rate> The remaining rate on the sieve was measured by the following method. 20 g of toner was placed in a plastic container and placed in a thermo-hygrostat at a temperature of 50°C and a relative humidity of 40% for 20 hours. After removing the container from the thermo-hygrostat, the toner was taken out and sieved through a 60-mesh sieve. The weight of the toner remaining on the sieve was measured, and the remaining rate (mass %), which is the ratio of this weight to the total weight of the toner, was calculated. The calculation results were shown as "sieve retention rate." The sieve retention rate was evaluated according to the following criteria. Table 6 shows the sieving residual rate and evaluation results for each toner. (Evaluation criteria) Yes:0% △: More than 0% and less than 10% ×: 10% or more

[0190] [Table 6]

[0191] <Consideration> From the above examples and comparative examples, it was found that by selecting amorphous polyester and crystalline polyester resins with appropriate solubility, the present toner is an excellent toner that has excellent low viscosity performance, low temperature fixing properties and adhesion, and does not impair the storage stability of the toner. In contrast, toners that do not satisfy the requirements of the present invention are inferior in either viscosity reduction ability or storage stability.

Claims

1. A toner comprising at least base particles and an external additive, the base particles contain an amorphous polyester resin and a crystalline polyester resin, Based on the Hansen solubility parameter theory, the volume V of the overlapping portion of the Hansen solubility spheres of the amorphous polyester resin and the crystalline polyester resin is 200 (J / cm ３ ) ３／２ Above, 800 (J / cm ３ ) ３／２ The toner is as follows:

2. A toner comprising at least base particles and an external additive, the base particles contain an amorphous polyester resin and a crystalline polyester resin, Based on the Hansen solubility parameter theory, the volume V (J / cm) of the overlapping area of ​​the Hansen solubility spheres of the amorphous polyester resin and the crystalline polyester resin ３ ) ３／２ and the content ratio X mass % of the crystalline polyester resin in the toner base particles, the value (V·X) / 100 being 1 / 100, is 20 (J / cm ３ ) ３／２ Above, 80 (J / cm ３ ) ３／２ The toner is as follows:

3. the crystalline polyester resin is a polycondensate of a carboxylic acid component and an alcohol component, 3. The toner according to claim 1, wherein the carboxylic acid component includes at least sebacic acid, and the alcohol component includes at least ethylene glycol and propylene glycol.

4. The values ​​of the dispersion parameter δD, polar parameter δP, and hydrogen bond parameter δH based on the Hansen solubility parameter theory of the amorphous polyester resin are in the range of 6 (J / cm ３ ) １／２ ~12 (J / cm ３ ) １／２ , the range of the polar term δP is 15 (J / cm ３ ) １／２ ~22 (J / cm ３ ) １／２ , the range of the hydrogen bond term δH is 6 (J / cm ３ ) １／２ ~12 (J / cm ３ ) １／２ 3. The toner according to claim 1, wherein

5. The base particle has a core-shell structure, and the amorphous polyester resin and the crystalline polyester resin contained in the core of the core-shell structure have a volume V of the overlapping portion or a volume V (J / cm ３ ) ３／２ and the content X% by mass of the crystalline polyester resin in the toner base particles, satisfies (V·X) / 100, which is 1 / 100 of the product.

6. 3. The toner according to claim 1, wherein the total content of bisphenol A and other compounds having a bisphenol structure in the toner is less than 100 ppm.

7. 3. The toner according to claim 1, wherein the total content of trimellitic anhydride and trimellitic acid in the toner is less than 1,000 ppm.

8. 3. The toner according to claim 1, wherein the melting point of the crystalline polyester resin is 62° C. or higher and 90° C. or lower.

9. 3. The toner according to claim 1, wherein the base particles further contain a colorant.

10. 3. The toner according to claim 1, wherein the volume median particle size (Dv50) is 3.0 μm or more and 7.0 μm or less.

11. 3. The toner according to claim 1, wherein the average circularity is 0.92 or more and 0.99 or less.

12. A toner cartridge filled with the toner according to claim 1 or 2.

13. An image forming apparatus using the toner according to claim 1 or 2.

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