Toner, toner cartridge, image forming apparatus, and toner manufacturing method

Abstract

To provide toner excellent in low-temperature fixability, storability, and adhesiveness, and containing a resin derived from a recycled raw material and / or a resin derived from a plant raw material.SOLUTION: There is provided toner comprising at least base particles and an external additive. The base particles contain an amorphous polyester resin and a crystalline polyester resin. The amorphous polyester resin is produced from the following raw materials a, b, and c. The toner has a total content of resin derived from a recycled raw material and resin derived from a plant raw material of 35 mass% or more with respect to the total mass, has a complex viscosity of 100,000 Pa s or less at 80°C and a complex viscosity of 2,000 Pa s or less at 110°C when measured at a measurement frequency of 6.28 rad / s and a heating rate of 4°C / min, and has a volume median particle diameter of 4.8 μm to 6.6 μm and an average circularity of 0.960 to 0.980. a: Monofunctional or difunctional carboxylic acid. b: Aliphatic alcohol having 1 to 4 functional groups. c: Polyethylene terephthalate.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 and an image forming apparatus containing the toner, and a method for producing the toner. [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 photosensitive drum. This electrostatic latent image is then developed with toner, and transferred to a printing medium such as transfer paper. The toner is then heated and fixed to form an 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] Low-temperature fixing toners that can be used to develop electrostatic images in commercial printing machines, particularly label printing machines used for food packaging, are being developed that can print on heat-resistant resin sheets such as polypropylene at temperatures of around 100°C (Patent Document 1). Furthermore, in food packaging applications, low environmental impact is also required. Specifically, bisphenol A, known as an environmental hormone, is considered a problem, and toners that do not contain this substance are being sought and developed. It is also desirable to reduce the content of other substances harmful to the human body and volatile organic compounds (VOCs) in toner as much as possible. Furthermore, from the viewpoint of reducing the environmental impact and carbon dioxide emissions in the manufacturing process, it is desirable to be able to select plant-derived monomers as toner raw materials (Patent Document 2).

[0005] On the other hand, in recent years, the waste problem has become increasingly serious, and there has been a strong demand for the recycling of various types of waste, from paper, bottles, and cans to large-sized waste. Among these recycled products, particularly plastics, PET bottles made from polyethylene terephthalate (PET) are collected to a certain extent and processed into fibers, which are then used in clothing, carpets, fillers, and furniture. Furthermore, the reuse of these as toner raw materials is also being considered (Patent Documents 3 and 4). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2022-5448 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-98149 [Patent Document 3] Japanese Patent Application Laid-Open No. 2009-192856 [Patent Document 4] Japanese Patent Application Publication No. 2023-138234 Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a toner that is suitable for commercial printing applications such as label printing, has excellent low-temperature fixing properties, storage stability and adhesion, does not contain any components that may impose an environmental load during use, and contains a resin derived from recycled raw materials or plant raw materials. [Means for solving the problem]

[0008] The present inventors have conducted extensive studies to solve the above-mentioned problems, and have found that the above-mentioned problems can be solved by using a toner comprising at least base particles and an external additive, wherein the base particles contain an amorphous polyester resin and a crystalline polyester resin, and the amorphous polyester resin is made from the following a, b, and c: a total content of resins derived from recycled materials and resins derived from plant materials is 35% by mass or more relative to the total mass of the toner; a complex viscosity at 80°C of 100,000 Pa·s or less and a complex viscosity at 110°C of 2,000 Pa·s or less, measured at a measurement frequency of 6.28 rad / s and a heating rate of 4°C / min; a volume median particle size (Dv50) of 4.8 μm or more and 6.6 μm or less; and an average circularity of 0.960 or more and 0.980 or less. a: monofunctional or difunctional carboxylic acid b: monofunctional to tetrafunctional aliphatic alcohol c: Polyethylene terephthalate That is, the present invention is summarized as follows.

[0009] [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, The amorphous polyester resin is made from the following a, b, and c as raw materials: a: monofunctional or difunctional carboxylic acid b: monofunctional to tetrafunctional aliphatic alcohol c: Polyethylene terephthalate The total content of recycled resin and plant-derived resin is 35% by mass or more of the total mass of the toner, The toner has a complex viscosity of 100,000 Pa·s or less at 80°C and a complex viscosity of 2,000 Pa·s or less at 110°C when measured at a measurement frequency of 6.28 rad / sec and a temperature rise rate of 4°C / min, The toner has a volume median particle size of 4.8 μm or more and 6.6 μm or less, A toner having an average circularity of 0.960 or more and 0.980 or less.

[0010] [2] The toner according to [1], wherein 70% by mass or more of the raw materials of the crystalline polyester resin are monomers derived from recycled raw materials and / or plant raw materials.

[0011] [3] The toner according to [1] or [2], wherein the complex viscosity at 80°C is 50,000 Pa·s or less.

[0012] [4] The toner according to any one of [1] to [3], wherein the complex viscosity at 80° C. is 25,000 Pa·s or more.

[0013] [5] The toner according to any one of [1] to [4], wherein the complex viscosity at 110° C. is 500 Pa·s or more.

[0014] [6] The toner according to any one of [1] to [5], wherein the complex viscosity at 110° C. is 1000 Pa·s or less.

[0015] [7] The toner according to any one of [1] to [6], wherein the base particles have a core-shell structure.

[0016] [8] The toner according to any one of [1] to [7], wherein the melting point of the crystalline polyester resin is 67°C or higher and 75°C or lower.

[0017] [9] The toner according to any one of [1] to [8], wherein the content of the crystalline polyester resin relative to the total mass of the base particles is 3% by mass or more and 20% by mass or less.

[0018]

[10] The toner according to any one of [1] to [9], wherein the crystalline polyester resin is a resin derived from a plant material.

[0019]

[11] The toner according to

[10] , wherein the plant material of the plant-derived resin contains at least sebacic acid and ethylene glycol.

[0020]

[12] The toner according to

[11] , wherein the plant material of the plant-derived resin further contains propylene glycol.

[0021]

[13] A toner cartridge containing the toner according to any one of [1] to

[12] .

[0022]

[14] An image forming apparatus containing the toner according to any one of [1] to

[12] .

[0023]

[15] A method for producing a toner containing at least base particles and an external additive, the base particles contain an amorphous polyester resin and a crystalline polyester resin, The amorphous polyester resin is made from the following a, b, and c as raw materials: a: monofunctional or difunctional carboxylic acid b: monofunctional to tetrafunctional aliphatic alcohol c: Polyethylene terephthalate The total content of recycled resin and plant-derived resin is 35% by mass or more of the total mass of the toner, The toner has a complex viscosity of 100,000 Pa·s or less at 80°C and a complex viscosity of 2,000 Pa·s or less at 110°C when measured at a measurement frequency of 6.28 rad / sec and a temperature rise rate of 4°C / min, The method for producing a toner includes a step of mixing and emulsifying each resin contained in the toner with an aqueous medium, an aggregation step, and an aging step. [Effects of the Invention]

[0024] According to the present invention, there are provided a toner which has excellent low-temperature fixing properties, storage stability and adhesion and contains a resin derived from recycled raw materials or a resin derived from plant raw materials, a toner cartridge and an image forming device which contain this toner, and a method for producing this toner. DETAILED DESCRIPTION OF THE INVENTION

[0025] 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.

[0026] 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," as well as "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."

[0027] [toner] A toner according to an embodiment of the present invention (hereinafter also referred to as "the toner") is a toner including at least base particles and an external additive, the base particles including an amorphous polyester resin and a crystalline polyester resin, and the amorphous polyester resin is made from the following a, b, and c as raw materials: a: monofunctional or difunctional carboxylic acid b: monofunctional to tetrafunctional aliphatic alcohol c: Polyethylene terephthalate The combined content of resins derived from recycled materials and resins derived from plant materials is 35% by mass or more of the total mass of the toner; the toner has a complex viscosity of 100,000 Pa·s or less at 80°C and 2,000 Pa·s or less at 110°C when measured at a measurement frequency of 6.28 rad / sec and a heating rate of 4°C / min; the toner has a volume median particle size of 4.8 μm or more and 6.6 μm or less; and the toner has an average circularity of 0.960 or more and 0.980 or less.

[0028] The base particles may further contain a colorant and / or wax, preferably a colorant and a wax, and may further contain a charge control agent and other components as necessary.

[0029] <Complex viscosity> When measured at a measurement frequency of 6.28 rad / sec and a heating rate of 4°C / min, the complex viscosity of this toner is 100,000 Pa·s or less at 80°C, and 2,000 Pa·s or less at 110°C. With both values ​​in this range, the toner melts onto the medium in one go when the specified temperature is applied, resulting in a toner with sufficient low-temperature fixing properties, particularly when printing on film. The complex viscosity of the present toner at 80°C is 100,000 Pa·s or less, preferably 50,000 Pa·s or less, and more preferably 30,000 Pa·s or less, from the viewpoint of fixing at a temperature of 100°C or less when printing on a film. On the other hand, from the viewpoint of the strength of the printed image, the complex viscosity at 80°C is preferably 10,000 Pa·s or more, more preferably 20,000 Pa·s or more, and even more preferably 25,000 Pa·s or more. From the viewpoint of low-temperature fixability, the complex viscosity of the toner at 110°C is 2000 Pa·s or less, preferably 1500 Pa·s or less, and more preferably 1000 Pa·s or less. On the other hand, from the viewpoint of printed image strength, the complex viscosity at 110°C is preferably 400 Pa·s or more, more preferably 500 Pa·s or more, and even more preferably 600 Pa·s or more. The complex viscosity at 80°C to 110°C can be measured by the method described in the Examples below.

[0030] 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. By dispersing a certain amount of crystalline polyester inside the amorphous polyester core, the crystalline polyester becomes compatible with the amorphous polyester when melted.

[0031] <Mechanism> Toner melts and adheres to media when subjected to a certain amount of heat, but in order to melt at lower temperatures, it needs to soften to a certain level of viscosity even at low temperatures. On the other hand, if the viscosity of the toner as a whole is too low or soft components are unevenly distributed on the surface of toner particles, toner blocking and other problems are likely to occur. Blocking is a phenomenon in which toner softens when exposed to a certain temperature, causing toner particles to adhere to each other. The occurrence of this phenomenon means that the binder resin is soft even at room temperature. Toner with extremely low resin viscosity results in poor adhesion between toner particles when printed, resulting in reduced strength of the printed image. This toner contains an amorphous polyester resin and a crystalline polyester resin as binder resins for the base particles. Even when the amorphous polyester resin is softened to a certain viscosity or lower, the presence of intramolecular hydrogen bonds strengthens the bonds between molecules, resulting in increased adhesion between toner particles, thereby preventing a decrease in the strength of the printed image. Furthermore, when an amorphous polyester resin is used in combination with a crystalline polyester resin, the crystalline polyester resin has a sharp melting property, making it compatible with the amorphous polyester resin and enabling a rapid reduction in the viscosity of the toner. In other words, it is believed that the use of an amorphous polyester resin in combination with a crystalline polyester resin can improve fixability in a specific temperature range without unnecessarily lowering the viscosity of the amorphous polyester resin. In particular, when the toner base particles have a core-shell structure, it becomes easier to achieve a balance between low-temperature fixability and print image strength. Furthermore, this toner uses the above-mentioned amorphous polyester and crystalline polyester, and when measured at a measurement frequency of 6.28 rad / sec and a temperature rise rate of 4°C / min, has a complex viscosity of 100,000 Pa·s or less at 80°C and a complex viscosity of 2,000 Pa·s or less at 110°C. By setting the complex viscosities at 80°C and 110°C within the above ranges, fixing becomes possible at low fixing temperatures (100°C or lower) used in film printing and the like, and at low fixing temperatures (100 to 140°C) used in general paper printing. Specifically, when the complex viscosities at 80°C and 110°C are within the above ranges, the toner becomes sufficiently soft even in the low temperature range of 100°C or lower, and has sufficient adhesion to film media, and therefore it is thought that the toner has sufficient fixing properties even in the low temperature range.

[0032] Furthermore, the amorphous polyester resin contained in this toner is made from the following a, b, and c as raw materials, and the total content of recycled raw material-derived resin and plant raw material-derived resin is 35 mass% or more relative to the total mass of the toner. As a result, as described below, the toner does not contain any components that may cause an environmental burden during use. Furthermore, the use of recycled raw material-derived resin and plant raw material-derived resin is effective in reducing the environmental burden and carbon dioxide emissions. a: monofunctional or difunctional carboxylic acid b: monofunctional to tetrafunctional aliphatic alcohol c: Polyethylene terephthalate

[0033] Furthermore, this toner has a volume median particle size of 4.8 μm or more and 6.6 μm or less, which allows for excellent image reproduction of fine details, and an average circularity of 0.960 or more and 0.980 or less, which means that it is less likely to cause printing problems such as PCR contamination and OPC filming.

[0034] <Regarding environmental impact> Toners for developing electrostatic images in commercial label printing machines are often required to have low-temperature fixability and low environmental impact. In food packaging applications, environmental hormones, which disrupt the natural hormone functions of living organisms, are of particular concern. In polyester toner, bisphenol A derivatives have traditionally been used as polyester resin monomers to achieve 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 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.

[0035] In view of these, the present inventors have realized a toner that is substantially free of bisphenol A and other compounds having a bisphenol structure by using an amorphous polyester resin made from the following raw materials a, b, and c as the amorphous polyester resin contained in the base particles. a: monofunctional or difunctional carboxylic acid b: monofunctional to tetrafunctional aliphatic alcohol c: Polyethylene terephthalate

[0036] Here, "substantially free of bisphenol A and other compounds having a bisphenol structure" means that the total content of bisphenol A and other compounds having a bisphenol structure is less than 100 ppm. Furthermore, the total content of bisphenol A and other compounds having a bisphenol structure in the present toner is preferably less than 50 ppm, and 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.

[0037] Furthermore, the present toner preferably has a total content of trimellitic anhydride and compounds containing trimellitic acid of 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.

[0038] Furthermore, the total content of antimony and tin is preferably less than 1000 ppm, more preferably less than 500 ppm, and even more preferably less than 100 ppm. In particular, the total content of heavy metals including antimony and tin 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 the use of antimony, tin, and other heavy metal components as much as possible.

[0039] <Resins derived from recycled materials and plant-based materials> In the present toner, the total content of the resin derived from recycled raw materials and the resin derived from plant raw materials is 35% by mass or more, which provides the effects of excellent low-temperature fixability and storage stability. In other words, by using resin derived from recycled raw materials, the content of trace impurities, unreacted monomers, low molecular weight oligomers, etc. in the resin is reduced, thereby improving storage stability, and by using resin derived from plant raw materials, the resin is highly crystallized, which is thought to contribute to low-temperature fixation. From the viewpoint of achieving both low-temperature fixability and storage stability and reducing the environmental impact, the total content of the resin derived from recycled raw materials and the resin derived from plant raw materials in the present toner is preferably 35% by mass or more, more preferably 40% by mass or more, and even more preferably 50% by mass or more. On the other hand, the upper limit of the total content of the resin derived from recycled raw materials and the resin derived from plant raw materials in the present toner may be 100% by mass.

[0040] The recycled raw materials are not particularly limited as long as they are raw materials recovered from recycled products, but among them, polyester resins such as PET (polyethylene terephthalate) and PBT (polybutylene terephthalate) are preferred. The weight-average molecular weight (Mw) of the polyester resin is preferably 30,000 to 100,000. The intrinsic viscosity number of the polyester resin is preferably 0.70 dL / g or more and 0.90 dL / g or less, and more preferably 0.80 dL / g or more and 0.85 dL / g or less.

[0041] The recycled raw material may be, for example, a material processed into flakes. Note that the recycled raw material may also include materials that are not recovered from recycled products (non-recycled materials), such as off-specification fiber waste or pellets. In the present toner, the resin derived from recycled raw materials is preferably contained in the base particles, and more preferably contained as a binder resin of the base particles from the viewpoint of achieving both environmental friendliness (high environmental consideration) and toner quality.

[0042] The plant raw material is not limited as long as it is a component made from a plant-derived compound, and may be, for example, a monomer unit in a resin, or a substance extracted, synthesized, or produced from sugarcane, corn, perilla, or the like. The plant-derived resin may be a crystalline resin or an amorphous resin. In the present toner, the plant-derived resin is preferably contained in the base particles, and more preferably contained as a binder resin for the base particles from the viewpoint of achieving both environmental friendliness (high environmental consideration) and toner quality.

[0043] The plant material is radioactive carbon isotopes 14 C concentration (hereinafter simply referred to as " 14 The concentration of HCl (sometimes referred to as "HCl concentration") is preferably 10 pMC or more, and more preferably 20 pMC or more. 14If the C concentration is 10 pMC or more, a more environmentally friendly toner (highly environmentally responsive) can be obtained, and the burden on the environment can be reduced. Note that "pMC" is an abbreviation for percent modern carbon, and is the carbon content of plant-based materials in 1950. 14 C and 12 Ratio to C ( 14 C / 12 C) is defined as 100pMC.

[0044] 14 C exists in nature (in the atmosphere), and while plants are active, it is taken up into the plants through photosynthesis and 14 C concentrations exist in the atmosphere 14 However, from the stage when plants cease to function, the carbon dioxide produced by photosynthesis is released. 14 C uptake stops, 14 According to the half-life of C, 5730 years 14 The carbon concentration decreases. In addition, fossil resources derived from living organisms have been around for tens of thousands to hundreds of millions of years since life ceased. 14 C concentration is barely detectable.

[0045] 14 The C concentration can be expressed as the biomass degree using the following formula. Biomass ratio (%) = 14 C concentration (pMC)×0.935

[0046] 14 A carbon concentration of 10 pMC or more means that the biomass ratio is 10% or more, which is a preferable concentration from the viewpoint of carbon neutrality.

[0047] 14 There are no particular limitations on the method for measuring the C concentration, and it can be selected appropriately depending on the purpose, but radiocarbon dating is particularly preferred. The measurement procedure is shown below. First, the toner is burned, and the CO2 (carbon dioxide) is reduced to obtain C (graphite). 14The carbon concentration is measured by AMS (Accelerator Mass Spectroscopy). This AMS measurement method is disclosed in, for example, Japanese Patent No. 4050051.

[0048] In addition, the radioactive carbon isotopes of this toner itself 14 The C concentration is preferably 10.8 pMC or more, more preferably 20 pMC or more.

[0049] Furthermore, the plant-derived monomer can be synthesized, for example, by the following steps.

[0050] Ethylene glycol can be obtained from sugarcane [ka]

[0051] Sebacic acid can be obtained from castor beans. [ka]

[0052] Propylene glycol can be obtained by fermenting and separating Sugarcane, just like ethylene glycol. It can also be extracted and separated from the essential oils of trees such as Japanese cypress and hinoki cypress.

[0053] <Toner base particles> The base particles of the toner (hereinafter also referred to as "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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] The toner base particles may further contain a colorant, a wax, a charge control agent, and other components as needed. 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.

[0059] <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. The amorphous polyester resin used in the present invention is made from the following raw materials a, b, and c. a: monofunctional or difunctional carboxylic acid b: monofunctional to tetrafunctional aliphatic alcohol c: Polyethylene terephthalate

[0060] The amorphous polyester resin used in the present invention is obtained by polycondensation reaction of a: monofunctional or difunctional carboxylic acid, b: mono- to tetrafunctional aliphatic alcohol monomer, and recycled PET resin as raw materials in the presence of an appropriate polymerization catalyst. The production method is not particularly limited, and can be produced using known polyester resin production methods. For example, a monomer mixture containing an acid component, an alcohol component, etc., and recycled PET resin are placed in a reaction vessel, heated to an elevated temperature, to carry out an esterification reaction or an ester exchange reaction, and the water or alcohol produced by the reaction is removed. A polycondensation reaction is then carried out, during which the pressure inside the reaction vessel is gradually reduced to 150 mmHg (20 kPa) or less, preferably 15 mmHg (2 kPa) or less, while the alcohol component is distilled off and the polycondensation is carried out. a: As the monofunctional or difunctional carboxylic acid, monovalent or divalent, that is, monofunctional or difunctional carboxylic acid monomers, and alkyl esters and acid anhydrides thereof can be used. b: As the mono- to tetrafunctional aliphatic alcohol, mono- to tetrahydric, that is, mono- to tetrafunctional alcohol monomers, alkyl esters thereof, and hydroxycarboxylic acids can be used. c: Polyethylene terephthalate is preferably derived from recycled raw materials as described below.

[0061] Usable carboxylic acid monomers include, for example, 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, and terephthalic acid. Examples of suitable carboxylic acids include dicarboxylic acids such as tetrachlorophthalic acid, chlorophthalic acid, nitrophthalic acid, p-carboxyphenylacetic acid, p-phenylene diacetic 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, anthracene dicarboxylic acid, and dodecenyl succinic acid. These may be used alone or in combination of two or more. Among these, as the dicarboxylic acid, maleic acid, adipic acid, fumaric acid, cyclohexane-3,5-diene-1,2-dicarboxylic acid, isophthalic acid, and terephthalic acid are preferred from the viewpoints of storage stability, handling properties, cost, and supply amount of the toner, and adipic acid, isophthalic acid, and terephthalic acid are more preferred, with adipic acid and terephthalic acid being even more preferred from the viewpoint of being able to use recycled raw materials and plant-derived raw materials.

[0062] Examples of alcohol monomers that can be used include dihydric alcohols such as ethylene glycol, neopentyl glycol, propanediol, 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 dihydric alcohols, ethylene glycol, neopentyl glycol, and 1,4-cyclohexanedimethanol are preferred from the viewpoints of reducing the colorability of the resin, ease of obtaining raw materials, and charging properties, with ethylene glycol and neopentyl glycol being more preferred, and ethylene glycol being even more preferred from the viewpoint of being able to use recycled raw materials and plant-derived raw materials. 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.

[0063] The ratio of polycarboxylic acid to polyhydric alcohol 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.

[0064] 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, the image strength of the printed matter is maintained. 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.

[0065] The glass transition temperature (Tg) of the amorphous polyester resin used for the shell is preferably within the range of 53 to 65°C. When the glass transition temperature of the amorphous polyester resin is equal to or higher than the lower limit, the image strength of the printed matter is maintained. When the glass transition temperature of the amorphous polyester resin is equal to or lower than 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.

[0066] The glass transition temperature of the amorphous polyester resin is measured by the method described in the Examples section below.

[0067] The softening temperature of the amorphous polyester resin for core use is preferably within the range of 95 to 130°C. If the softening temperature is equal to or higher than the lower limit, the image strength of the printed matter is maintained. If the softening temperature is equal to or lower than the upper limit, the 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.

[0068] The softening temperature of the amorphous polyester resin used for the shell is preferably in the range of 105 to 140°C. If the softening temperature is above the lower limit, the image strength of the printed matter is maintained. 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.

[0069] The softening temperature of the amorphous polyester resin is measured by the method described in the Examples section below.

[0070] 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.

[0071] The acid value of the amorphous polyester resin is measured by the method described in the Examples section below.

[0072] 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 image strength can be obtained by making the mass average molecular weight (Mw) of the amorphous polyester resin 5000 or more, and complex viscosity can be reduced by making the mass average molecular weight (Mw) of the amorphous polyester resin 30000 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.

[0073] 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.

[0074] 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 print strength 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.

[0075] 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 print strength 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.

[0076] The total content of the amorphous polyester resin in the toner base particles is preferably 50% 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 50% by mass or more, a toner with excellent adhesion to a medium, printing durability, and flexibility can be obtained. From this perspective, the total content of the amorphous polyester resin in the toner base particles is particularly preferably 60% by mass or more, and even more preferably 70% 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, a toner with excellent low-temperature fixability and color development can be obtained. 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.

[0077] <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).

[0078] The crystalline polyester resin is obtained by a polycondensation reaction of raw materials, such as a dicarboxylic acid monomer (including derivatives; hereinafter, sometimes referred to as a "dicarboxylic acid component") and an aliphatic dialcohol monomer (including derivatives; hereinafter, sometimes referred to as an "aliphatic dialcohol component"), in the presence of an appropriate polymerization catalyst.

[0079] The dicarboxylic acid component is not particularly limited, and examples thereof include fumaric acid, succinic acid, adipic acid, sebacic acid, dodecanedioic acid, tetradecanedioic acid, terephthalic acid, and isophthalic acid. Among these, adipic acid, sebacic acid, and dodecanedioic acid are preferred, dodecanedioic acid and sebacic acid are more preferred, and sebacic acid is even more preferred, from the viewpoints of crystallinity control, melting point control, and the ability to use plant-derived raw materials. These dicarboxylic acid components may be used alone or in combination of two or more.

[0080] The aliphatic dialcohol component is not particularly limited, and examples thereof include ethylene glycol, 1,3-propanediol, 1,2-propanediol (propylene glycol), 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, 15-pentadecanediol, and 1,16-hexadecanediol. Among these, from the viewpoints of crystallinity control, melting point control, and the ability to use plant-derived raw materials, ethylene glycol, 1,2-propanediol (propylene glycol), 1,3-propanediol, and 1,6-hexanediol are preferred, ethylene glycol, 1,2-propanediol (propylene glycol), and 1,6-hexanediol are more preferred, and ethylene glycol and propylene glycol are even more preferred. These aliphatic alcohol components may be used alone or in combination of two or more.

[0081] The ratio of the dicarboxylic acid component and the aliphatic dialcohol component to be subjected to the polycondensation reaction 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.

[0082] From the viewpoint of reducing the environmental load and carbon dioxide emissions, it is preferable that 70 mass % or more of the raw materials for such a crystalline polyester resin are monomers derived from recycled raw materials and / or plant raw materials. This proportion is more preferably 80% by mass or more, particularly preferably 90% by mass or more, and may be 100% by mass. From the viewpoint of reducing the environmental load and reducing carbon dioxide emissions, it is most preferable that the crystalline polyester resin is a resin derived from a plant material. In this case, it is preferable that the plant material of the plant-derived resin contains at least sebacic acid and ethylene glycol from the viewpoint of maintaining high crystallinity, and it is even more preferable that the plant material further contains propylene glycol from the viewpoint of controlling dispersibility in the toner.

[0083] The melting point (Tm) of the crystalline polyester resin is preferably in the range of 62 to 90°C, particularly in the range of 67 to 75°C. If the melting point is above the lower limit, blocking of toner particles is not significantly worsened and image strength 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 crystalline polyester resin.

[0084] The acid value of the crystalline polyester resin is preferably 60 mgKOH / g or less from the viewpoint of ease of forming aggregated particles. If the acid value is higher than 60 mgKOH / g, the dispersion liquid becomes highly stable and aggregation becomes difficult. The acid value of the crystalline polyester resin is more preferably 30 mgKOH / g or less, and even more preferably 15 mgKOH / g or less.

[0085] The acid value of the crystalline polyester resin is measured by the method described in the Examples section below.

[0086] 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.

[0087] 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 image strength 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.

[0088] From the viewpoint of the balance between complex viscosity and toner surface properties, 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 88:12, relative to a total of 100 parts by mass.

[0089] <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.

[0090] 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). As described above, the toner of the present invention preferably has a total content of antimony and tin of less than 1000 ppm, and therefore it is not preferable to use a tin-based catalyst or antimony trioxide as the catalyst.

[0091] Examples of titanium catalysts include titanium alkoxide compounds having an alkoxy group, titanium carboxylate, titanyl carboxylate, titanyl carboxylate salts, and titanium chelate compounds. Examples of titanium alkoxide compounds having an alkoxy group include tetramethoxytitanium, tetraethoxytitanium, tetrapropoxytitanium, tetrabutoxytitanium, tetrapentoxytitanium, tetraoctoxytitanium, etc. Among these, tetrabutoxytitanium is preferred. The titanium catalyst may be used alone or in combination of two or more kinds.

[0092] <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.

[0093] 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.

[0094] <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, the core may be separated as a domain and encapsulated, the shell may be separated as a domain and encapsulated, or the wax may be present separated on the surface of the toner.

[0095] The type of wax contained in the present toner is not limited, but it is preferable that the toner contains an ester wax.

[0096] (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.

[0097] (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.

[0098] (amount of wax) The amount of wax contained in the present toner is preferably 3 to 20% by mass, more preferably 5 to 10% by mass, based on the total mass (100% by mass) of the present toner base particles.

[0099] <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.

[0100] 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.

[0101] <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 to the base particle surface in a point-contact manner or embedded therein, and a part or all of the external additive may be present in a dispersed or aggregated state on the base particle surface. 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.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] <Form of this toner> The volume median particle diameter (Dv50) of the present toner is 4.8 μm or more and 6.6 μm or less. From the viewpoint of image reproducibility and toner consumption, the volume median particle diameter (Dv50) of the present toner is 6.6 μm or less, preferably 6.4 μm or less, more preferably 6.2 μm or less, and even more preferably 6.0 μm or less. On the other hand, from the viewpoint of environmental safety against dust, the volume median particle diameter (Dv50) of the present toner is 4.8 μm or more, more preferably 4.9 μm or more, and particularly preferably 5.0 μm or more. In the present invention, the "volume median particle size (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 is such that the average circularity measured using a flow particle image analyzer FPIA-3000 (manufactured by Malvern Instruments) is 0.960 or more and 0.980 or less. From the viewpoint of image reproducibility, the average circularity is preferably 0.955 or more, more preferably 0.960 or more, and even more preferably 0.965 or more, while from the viewpoint of preventing OPC filming and in-machine scattering, the average circularity is preferably 0.990 or less, more preferably 0.985 or less, and even more preferably 0.980 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. When the viscosity of the binder resin during emulsification is high and the polymer primary particles do not become small enough to reach the desired particle size, an emulsifier capable of pressurizing the polymer to atmospheric pressure or higher is used to raise the temperature to the higher of either the melting point or the glass transition temperature of the resin, thereby emulsifying the polymer in a state where the viscosity of the resin is reduced, thereby obtaining primary particles having 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] (agglomeration 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 carry out coagulation, the electrolyte may be any of an acid, an alkali, or a salt, and may be either organic or inorganic. Specific examples of the electrolyte include acids such as hydrochloric acid, nitric acid, sulfuric acid, and citric acid; alkalis such as sodium hydroxide, potassium hydroxide, and aqueous ammonia; and salts such as sodium hydroxide, potassium hydroxide, and aqueous ammonia. , NaCl, KCl, LiCl, Na2SO4, K2SO4, Li2SO4, MgCl2, CaCl2, MgSO4, CaSO4, ZnSO4, Al2(SO4)3, Fe2(SO4)3, CH3COONa, C6H5SO3Na, 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, or to be configured to perform offset printing, or even 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."

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

[0146] <Medium diameter (D50)> The median diameter (D50) 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) 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 to a dispersoid concentration of 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 2000 to 2500 particles.

[0149] <Mass average molecular weight (Mw)> The Mw of the polyester resin was determined by standard styrene conversion from the retention time corresponding to the peak value of the elution curve obtained by GPC. 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 emulsion solid concentration (unit: mass %) 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] <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 6.28 rad / s, the initial temperature was 40°C, the delay time before measurement was 3 minutes, the automatic tension adjustment (pulling direction, initial force was 0, automatic tension sensitivity was 2.0 g, automatic tension switching elastic modulus was 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 values ​​at 80°C and 110°C were calculated by reading the complex viscosity values ​​at each point on a graph created from the obtained data.

[0156] Next, the wax dispersion, pigment dispersion, polymer primary particle dispersion, amorphous polyester dispersion, and crystalline polyester dispersion used in the examples and comparative examples will be described.

[0157] <Wax dispersion W1> 30 parts of ester wax 1 (stearyl behenate, melting point 67°C) as a wax, 1.93 parts of a 20% aqueous solution of sodium dodecylbenzenesulfonate (hereinafter referred to as 20% aqueous DBS solution), and 68.7 parts of demineralized water were placed in a CSTR-type agitator equipped with a 45-degree inclined three-stage paddle blade, heated to 90°C in the agitator, and mixed for 20 minutes. Next, while this dispersion was heated to 90°C, it was subjected to circulating emulsification under a pressure of 25 MPa using a valve homogenizer (Gaulin, 15-M-8PA type). The particle size was measured using a Nanotrac and the dispersion was continued until the median diameter (D50) reached 245 nm, producing wax dispersion W1 (emulsion solids concentration: 30.5%).

[0158] <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% 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. This premix was then fed into a wet bead mill as a raw slurry and dispersed. 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%.

[0159] <Amorphous polyester resin> Amorphous polyester resins A, B, and C were produced as follows. The polycarboxylic acid component, polyhydric alcohol component, recycled PET resin, and polymerization catalyst were charged into a reaction vessel equipped with a distillation column, with the charge compositions shown in Table 1. The amount of polymerization catalyst is the amount (ppm) relative to the total amount of the polycarboxylic acid component and terephthalic acid in the PET. 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 amorphous polyester resin was obtained. The physical properties (glass transition temperature, softening temperature, mass average molecular weight, acid value) of the obtained amorphous polyester resins A, B, and C were measured. The results are shown in Table 1.

[0160] [Table 1]

[0161] <Amorphous polyester 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 vacuum distillation at 80°C using an aspirator to obtain amorphous polyester dispersion P1. The median diameter (D50) of the amorphous polyester resin particles in amorphous polyester dispersion P1 was measured using a Nanotrac and was found to be 180 nm.

[0162] <Amorphous polyester 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 dispersion P2. The median diameter (D50) of the amorphous polyester resin particles in amorphous polyester dispersion P2 was measured using a Nanotrac and was found to be 190 nm.

[0163] <Amorphous polyester dispersion P3> 25 parts of amorphous polyester resin C 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 dispersion P3. The median diameter (D50) of the amorphous polyester resin particles in amorphous polyester dispersion P3 was measured using a Nanotrac and was found to be 200 nm.

[0164] <Crystalline polyester resin> Crystalline polyester resins A, B, and C 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. 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 resulting crystalline polyester resins A, B, and C were measured, and the results are shown in Table 2.

[0165] [Table 2]

[0166] <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). The solvent was then removed by vacuum distillation at 80°C using an aspirator to obtain crystalline polyester dispersion C1. The median diameter (D50) of the crystalline polyester resin particles in crystalline polyester dispersion C1 was measured using a Nanotrac and found to be 180 nm.

[0167] <Crystalline polyester resin dispersion C2> 72 parts of crystalline polyester resin B was dissolved in 408 parts of ethyl acetate, and 12.0 parts of a 20% DBS aqueous solution and 708 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). The solvent was then removed by vacuum distillation at 80°C using an aspirator to obtain crystalline polyester dispersion C2. The median diameter (D50) of the crystalline polyester resin particles in crystalline polyester dispersion C2 was measured using a Nanotrac and found to be 190 nm.

[0168] <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). The solvent was then removed by vacuum distillation at 80°C using an aspirator to obtain crystalline polyester dispersion C3. The median diameter (D50) of the crystalline polyester resin particles in crystalline polyester dispersion C3 was measured using a Nanotrac and was found to be 185 nm.

[0169] [Example 1] Toner T1 was prepared as follows.

[0170] A mixer equipped with a stirrer, a heating / cooling device, and various raw material and auxiliary feeders was charged with 73.0 parts (solids) of amorphous polyester dispersion P2, 0.05 parts (solids) of 20% DBS aqueous solution, 7.0 parts (solids) of wax dispersion W1, 5.0 parts (solids) of crystalline polyester dispersion C1, 135 parts of demineralized water, 3.047 parts (solids) of 10% magnesium sulfate heptahydrate aqueous solution, 0.082 parts (solids) of 1% aluminum sulfate aqueous solution, and 5.0 parts (solids) of pigment dispersion G1. The internal temperature was raised to 34.0°C over 40 minutes and then to 38.0°C over 90 minutes. The volume median particle size (Dv50) was measured using a Multisizer and found to be 5.46 μm. Next, a mixture of 10.0 parts (solids) of the amorphous polyester dispersion P3 for the shell and 0.2 parts (solids (2 parts per 100 parts of polyester)) of a 20% DBS aqueous solution was added dropwise over 30 minutes. 30 minutes after the completion of the dropwise addition, 232 parts of demineralized water and 5.0 parts (solids) 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 system was then cooled to 30°C over 30 minutes.

[0171] 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.

[0172] 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 composition of each material in this toner T1 is as shown in Table 3. The volume median particle diameter (Dv50) and average circularity of the obtained toner T1 were measured. The results are shown in Table 4. The complex viscosity of the toner T1 was also measured, and the results are shown in Table 4.

[0173] The toner T1 obtained in Example 1 does not contain any bisphenol A derivatives, trimellitic acid components, antimony, or tin in its manufacturing process, and therefore does not contain these components. The same applies to the toners T2 to T4 in Examples 2 to 4 below.

[0174] [Example 2] Toner T2 was prepared in the same manner as Toner T1 in Example 1, except that the amounts of Amorphous Polyester Dispersion P2 were changed to 75.0 parts (solid content), the Crystalline Polyester Dispersion C1 to 10.0 parts (solid content), the Wax Dispersion W1 to 0.0 parts (no addition), and the Amorphous Polyester Dispersion P1 for the shell to 10.0 parts (solid content). The core / shell structure of this toner T2 is as shown in Table 3. The volume median particle size (Dv50) and average circularity of the obtained toner T2 were measured. The results are shown in Table 4. The complex viscosity of toner T2 was also measured, and the results are shown in Table 4.

[0175] [Example 3] Toner T3 was produced in the same manner as Toner T1 in Example 1, except that the amounts of Amorphous Polyester Dispersion P2 were changed to 73.0 parts (solid content), Crystalline Polyester Dispersion C1 to 7.0 parts (solid content), Wax Dispersion W1 to 5.0 parts (solid content), and Amorphous Polyester Dispersion P3 for the shell were changed to 10.0 parts (solid content). The core / shell structure of this toner T3 is as shown in Table 3. The volume median particle diameter (Dv50) and average circularity of the obtained toner T3 were measured. The results are shown in Table 4. The complex viscosity of toner T3 was also measured, and the results are shown in Table 4.

[0176] [Example 4] Toner T4 was produced in the same manner as Toner T1 in Example 1, except that the amounts of Amorphous Polyester Dispersion P2 were changed to 73.0 parts (solid content), Crystalline Polyester Dispersion C3 to 7.0 parts (solid content), Wax Dispersion W1 to 5.0 parts (solid content), and Amorphous Polyester Dispersion P3 for the shell were changed to 10.0 parts (solid content). The core / shell structure of this toner T4 is as shown in Table 3. The volume median particle diameter (Dv50) and average circularity of the obtained toner T4 were measured. The results are shown in Table 4. The complex viscosity of toner T4 was also measured, and the results are shown in Table 4.

[0177] [Comparative Example 1] Toner T5 was produced in the same manner as Toner T1 in Example 1, except that the amounts of Amorphous Polyester Dispersion P2 were changed to 75.0 parts (solid content), the Crystalline Polyester Dispersion C2 to 3.0 parts (solid content), the Wax Dispersion W1 to 7.0 parts (solid content), and the Amorphous Polyester Dispersion P1 for the shell to 10.0 parts (solid content). The core / shell structure of this toner T5 is as shown in Table 3. The volume median particle diameter (Dv50) and average circularity of the obtained toner T5 were measured. The results are shown in Table 4. The complex viscosity of toner T5 was also measured, and the results are shown in Table 4.

[0178] Comparative Example 2 Toner T6 was produced in the same manner as Toner T1 in Example 1, except that the amounts of Amorphous Polyester Dispersion P2 were changed to 68.0 parts (solid content), Crystalline Polyester Dispersion C2 to 10.0 parts (solid content), Wax Dispersion W1 to 7.0 parts (solid content), and Amorphous Polyester Dispersion P3 for the shell to 10.0 parts (solid content). The core / shell structure of this toner T6 is as shown in Table 3. The volume median particle diameter (Dv50) and average circularity of the obtained toner T6 were measured. The results are shown in Table 4. The complex viscosity of toner T6 was also measured, and the results are shown in Table 4.

[0179] Comparative Example 3 Toner T7 was produced in the same manner as Toner T1 in Example 1, except that the amounts of amorphous polyester dispersion P1 and P2 were changed to 40.0 parts (solid content), 33.0 parts (solid content), crystalline polyester dispersion C1 to 5.0 parts (solid content), wax dispersion W1 to 7.0 parts (solid content), and amorphous polyester dispersion P1 for the shell to 10.0 parts (solid content). The core / shell structure of this toner T7 is as shown in Table 3. The volume median particle diameter (Dv50) and average circularity of the obtained toner T7 were measured. The results are shown in Table 4. The complex viscosity of toner T7 was also measured, and the results are shown in Table 4.

[0180] [Table 3]

[0181] [Evaluation of printability and storage stability] <Low temperature fixability evaluation> The obtained toner was applied to a PET film (Diafoil T-600E, manufactured by Mitsubishi Chemical Corporation) at a toner adhesion amount of approximately 0.6 mg / cm using a commercially available printer equipped with a non-magnetic single-component developing rubber roller, a metal blade, and an organic photoreceptor charged by a charging roller (PCR), with the fixing unit removed, at a printing speed of 16 ppm. 2An unfixed toner image was printed. The thermal roll fixing machine used had a roller diameter of 27 mm, a nip width of 9 mm, and a heater on the upper roller. The roller surface was made of PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), and silicone oil was not applied. The roller surface temperature was set to 130°C, and fixing was performed at a fixing speed of 229 mm / sec to prepare an evaluation sample. Cellotape (registered trademark) was adhered to the evaluation sample and then peeled off. The area percentage (%) of the toner remaining on the PET film of the evaluation sample was measured, assuming the area adhered with the Cellotape (registered trademark) was 100%. Low-temperature fixability was evaluated based on this area percentage using the following evaluation criteria. In this example, a grade of "Fair" or better was considered acceptable. The evaluation results are shown in Table 4. (Evaluation criteria) Good: Toner remained on 70% or more of the PET film. △: Toner remained on 40% or more and less than 70% of the PET film. x: Toner remained on less than 40% of the PET film, or the fixed image was offset.

[0182] <Storage evaluation> 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%, where it was kept for 20 hours. After removing the container from the thermo-hygrostat, the toner was taken out and sieved through a #60 sieve. The weight of the toner remaining on the sieve was measured to determine the residual rate. A low residual rate means that there are no problems such as sticking due to storage and the storage stability is good. The evaluation criteria for storage stability were as follows. In this example, a rating of "△" or better was considered to be acceptable. The results are shown in Table 4. (Evaluation criteria) ○: Residual rate less than 0.5% △: Residual rate 0.5% or more and less than 2.0% ×: Survival rate 2.0% or more

[0183] <Adhesion evaluation> The obtained toner was applied to a PET-coated glossy recording paper (water-resistant paper Kareka, manufactured by Kokusai Pulp & Paper Co., Ltd.) with a deposition amount of approximately 0.8 mg / cm using two toner cartridges in a commercially available printer with a printing speed of 16 ppm, a non-magnetic single-component developer rubber roller, a metal blade, and an organic photoreceptor charged by a charging roller (PCR), and the fixing unit removed. 2 An unfixed toner image was printed. The heat roll fixing machine used had a roller diameter of 27 mm, a nip width of 9 mm, and a fixing speed of 95 mm / sec. The upper roller had a heater, the roller surface was made of PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), and no silicone oil was applied. The roller surface temperature was set to 150°C, and the adhesion amount was approximately 0.8 mg / cm 2 The recording paper bearing the unfixed toner image was transported to the fixing nip section, and a fixed image was obtained. An abrasion test was performed by scraping the fixed image with a vertically placed flathead screwdriver. The tip width of the flathead screwdriver was 1 mm, and a weight of 250 g was applied to the tip. The scraping test was performed three times in total, with a movement distance of 2 cm. The movement speed was approximately 1 cm / s, and the angle between the movement direction and the tip of the flathead screwdriver was 90°. The degree of abrasion was visually observed and evaluated according to the following criteria. In this example, a grade of "△" or better was considered to be acceptable. The evaluation results are shown in Table 4. (Evaluation criteria) ○: No scraping was performed at all, or scraping left one or less small white dots. △: The length of the scraped line was less than 3 mm, or there were multiple small white dots. ×: The length of the scraped line was 3 mm or more.

[0184] Table 4 also lists the total content of recycled resin and plant-derived resin relative to the total mass of the toner, calculated from the content ratio of recycled resin and plant-derived resin in the crystalline polyester resin and amorphous polyester resin used.

[0185] [Table 4]

[0186] From the above examples and comparative examples, it was found that the toner contains an amorphous polyester resin made from a specific compound, and by adjusting the total content of the resin derived from recycled materials and the resin derived from plant materials, the complex viscosity at 80°C and 110°C, the volume median particle size, and the average circularity to appropriate ranges, the toner has excellent low-temperature fixing properties, storage stability, and adhesion. The reason for this is thought to be that the use of resin derived from recycled raw materials reduces the content of trace impurities, unreacted monomers, low molecular weight oligomers, etc. in the resin, improving storage stability, and that the use of resin derived from plant raw materials results in high crystallization of the resin, contributing to low-temperature fixation.

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, The amorphous polyester resin is made from the following a, b, and c as raw materials: a: monofunctional or difunctional carboxylic acid b: mono- to tetrafunctional aliphatic alcohol c: polyethylene terephthalate The total content of the resin derived from recycled materials and the resin derived from plant materials is 35% by mass or more relative to the total mass of the toner, the toner has a complex viscosity of 100,000 Pa s or less at 80°C and a complex viscosity of 2,000 Pa s or less at 110°C when measured at a measurement frequency of 6.28 rad / sec and a temperature rise rate of 4°C / min; The toner has a volume median particle size of 4.8 μm or more and 6.6 μm or less, A toner having an average circularity of 0.960 or more and 0.980 or less.

2. 2. The toner according to claim 1, wherein 70% by mass or more of raw materials for the crystalline polyester resin are monomers derived from recycled raw materials and / or plant raw materials.

3. 3. The toner according to claim 1, wherein the complex viscosity at 80°C is 50,000 Pa·s or less.

4. 3. The toner according to claim 1, wherein the complex viscosity at 80°C is 25,000 Pa·s or more.

5. 3. The toner according to claim 1, wherein the complex viscosity at 110°C is 500 Pa·s or more.

6. 3. The toner according to claim 1, wherein the complex viscosity at 110°C is 1000 Pa·s or less.

7. The toner according to claim 1 or 2, wherein the base particles have a core-shell structure.

8. 3. The toner according to claim 1, wherein the melting point of the crystalline polyester resin is 67°C or higher and 75°C or lower.

9. 3. The toner according to claim 1, wherein the content of the crystalline polyester resin relative to the total mass of the base particles is 3% by mass or more and 20% by mass or less.

10. 3. The toner according to claim 1, wherein the crystalline polyester resin is a resin derived from a plant material.

11. The toner according to claim 10 , wherein the plant material of the plant-derived resin contains at least sebacic acid and ethylene glycol.

12. The toner according to claim 11 , wherein the plant material of the plant-derived resin further contains propylene glycol.

13. A toner cartridge containing the toner according to claim 1 or 2.

14. An image forming apparatus containing the toner according to claim 1 or 2.

15. A method for producing a toner containing at least base particles and an external additive, the base particles contain an amorphous polyester resin and a crystalline polyester resin, The amorphous polyester resin is made from the following a, b, and c as raw materials: a: monofunctional or difunctional carboxylic acid b: mono- to tetrafunctional aliphatic alcohol c: polyethylene terephthalate The total content of the resin derived from recycled materials and the resin derived from plant materials is 35% by mass or more relative to the total mass of the toner, the toner has a complex viscosity of 100,000 Pa s or less at 80°C and a complex viscosity of 2,000 Pa s or less at 110°C when measured at a measurement frequency of 6.28 rad / sec and a temperature rise rate of 4°C / min; The method for producing a toner includes a step of mixing and emulsifying each resin contained in the toner with an aqueous medium, an aggregation step, and an aging step.

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