Toner, toner cartridge, image-forming device, and method for producing toner

Abstract

Provided is a toner containing at least: mother particles and an external additive. The mother particles contain an amorphous polyester resin and a crystalline polyester resin. When the toner is analyzed at an analysis frequency of 6.28 rad / second and a temperature increase rate of 4°C / minute, the complex viscosity at 80°C is no greater than100000 Pa•s and the complex viscosity at 110°C is no greater than 2000 Pa•s. When 20 g of the toner is disposed inside a thermostatic chamber at a temperature of 50°C and relative humidity of 40%, left to stand for 20 hours, and then sifted through a 60 mesh sieve, the percentage remaining on the sieve is less than 5%.

Description

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

[0001] The present invention relates to a toner that has sufficient low-temperature fixability when printed on a film and also produces strong printed images, a toner cartridge and an image forming apparatus containing the toner, and a method for producing the toner.

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

[0005] When forming an image on a print medium, the toner is heated to fix it, and the power required for this heating accounts for the majority of the power consumption of image forming devices such as copiers. For this reason, toner is required to have the property of being fixed at a lower temperature (low-temperature fixability).

[0006] In the aforementioned commercial printing, the printing medium is often not only conventional paper but also plastic films such as polypropylene (PP) and polyethylene terephthalate (PET). These plastic films are prone to deterioration when exposed to excessive heat, so they require even better low-temperature fixability than conventional paper media. Furthermore, depending on the viscosity of the toner, the printed image may be weak and brittle.

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

[0008] Furthermore, in the aforementioned commercial printing, electrostatic image developing toners used in label printing machines for food packaging and the like are often required to have low environmental impact. Specifically, bisphenol A, known as an environmental hormone, is considered problematic, and toners that do not contain this substance are in demand. It is also desirable to minimize the content of other substances harmful to the human body and volatile organic compounds (VOCs) in toners.

[0009] JP 2023-147690 A

[0010] Conventionally, there are toners with excellent low-temperature fixability, such as those described in Patent Document 1, but the low-temperature fixability is insufficient for use in printing on plastic films. Also, printed images with higher strength are desired.

[0011] SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a toner that has sufficient low-temperature fixability when printing on film and also has excellent strength in printed images.

[0012] The present inventors have conducted extensive research to solve the above-mentioned problems, and have found that the above-mentioned problems can be solved by using a toner that contains at least base particles and an external additive, wherein the base particles contain an amorphous polyester resin and a crystalline polyester resin, and have 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 temperature rise rate of 4°C / min, and when 20 g of the toner is placed in a thermo-hygrostat kept at a temperature of 50°C and a relative humidity of 40%, and held for 20 hours, and then sieved through a 60-mesh sieve, the remaining percentage on the sieve is less than 5%.

[0013] [1] 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 wherein 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, and wherein when 20 g of the toner is placed in a thermo-hygrostat kept at a temperature of 50°C and a relative humidity of 40%, and is held therein for 20 hours, and then sieved, the remaining percentage on the sieve is less than 5%.

[0014] [2] The toner according to [1], wherein the base particles have a core-shell structure.

[0015] [3] The toner according to [1] or [2], wherein the total content of bisphenol A and other compounds having a bisphenol structure in the toner is less than 100 ppm.

[0016] [4] The toner according to any one of [1] to [3], wherein the total content of trimellitic anhydride and trimellitic acid in the toner is less than 1000 ppm.

[0017] [5] The toner according to any one of [1] to [4], wherein the total content of antimony and tin in the toner is less than 1000 ppm.

[0018] [6] The toner according to any one of [1] to [5], wherein the melting point of the crystalline polyester resin is 62° C. or higher and 90° C. or lower.

[0019] [7] The toner according to any one of [1] to [6], wherein the glass transition temperature of the amorphous polyester resin is 45° C. or higher and 65° C. or lower.

[0020] [8] The toner according to any one of [1] to [7], wherein the acid value of the amorphous polyester resin is 4 mgKOH / g or more and 20 mgKOH / g or less.

[0021] [9] The toner according to any one of [1] to [8], wherein the complex viscosity at 80° C. is 30,000 Pa·s or less.

[0022]

[10] The toner according to any one of [1] to [9], wherein the complex viscosity at 110° C. is 1000 Pa·s or less.

[0023]

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

[10] , wherein the crystalline polyester resin is a polyester resin other than polyethylene terephthalate.

[0024]

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

[11] , which does not have a crystal melting peak in a temperature range of 200° C. or higher in differential scanning calorimetry (DSC).

[0025]

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

[12] , wherein the amorphous polyester resin has a structure derived from two or more kinds of aliphatic polyhydric alcohols as a polyester-forming structure.

[0026]

[14] The toner according to

[13] , wherein the aliphatic polyhydric alcohol contains a branched-chain aliphatic polyhydric alcohol.

[0027]

[15] The toner according to

[13] or

[14] , wherein the aliphatic polyhydric alcohol contains a dihydric alcohol and a trihydric or higher alcohol.

[0028]

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

[15] , wherein the base particles further contain a colorant.

[0029]

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

[16] , wherein the volume median particle size (Dv50) is 3.0 μm or more and 7.0 μm or less.

[0030]

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

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

[0031]

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

[18] .

[0032]

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

[18] .

[0033]

[21] A method for producing a toner, the method comprising at least a step of producing primary polymer particles, an aggregation step, a ripening step, and an external addition step, wherein the toner comprises at least base particles and an external additive, the base particles contain an amorphous polyester resin, a crystalline polyester resin, and a colorant, 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, and when 20 g of the toner is placed in a thermo-hygrostat kept at a temperature of 50°C and a relative humidity of 40%, and is held therein for 20 hours, and then sieved, the residual rate on a 60-mesh sieve is less than 5%, and the primary polymer particles are obtained by emulsion polymerization.

[0034] According to the present invention, there are provided a toner that has sufficient low-temperature fixability when printing on a film and also has excellent printed image strength, a toner cartridge and an image forming apparatus that contain this toner, and a method for producing this toner.

[0035] The following describes in detail the mode for carrying out the present invention (hereinafter, "embodiments of the invention"). The present invention is not limited to the following embodiments, and various modifications can be made within the scope of the invention.

[0036] In this specification, when "X to Y" (X and Y are any numbers) is expressed, unless otherwise specified, it means "X or more and Y or less," and also includes the meaning "preferably larger than X" or "preferably smaller than Y." Furthermore, when "X or more" (X is any number) or "Y or less" (Y is any number), it also includes the meaning "preferably larger than X" or "preferably smaller than Y."

[0037] [Toner] The toner according to an embodiment of the present invention (hereinafter referred to as "the toner") is a toner containing at least base particles and external additives, wherein the base particles contain an amorphous polyester resin and a crystalline polyester resin, and when measured at a measurement frequency of 6.28 rad / sec and a temperature rise rate of 4°C / min, 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, and when 20 g of the toner is placed in a thermo-hygrostat kept at a temperature of 50°C and a relative humidity of 40%, and is held therein for 20 hours, and then sieved, the remaining percentage on the sieve is less than 5%.

[0038] 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.

[0039] <Complex Viscosity> When measured at a measurement frequency of 6.28 rad / sec and a temperature rise rate of 4°C / min, the complex viscosity of the present toner at 80°C is 100,000 Pa·s or less, and the complex viscosity at 110°C is 2,000 Pa·s or less. When both are within these ranges, the toner quickly fuses to a printing medium when a predetermined temperature is applied, resulting in a toner with sufficient low-temperature fixability, particularly when printing on film. From the viewpoint of fixing at a temperature of 100°C or less when printing on film, the complex viscosity of the present toner at 80°C is preferably 100,000 Pa·s or less, more preferably 50,000 Pa·s or less, and even more preferably 30,000 Pa·s or less. 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, and more preferably 20,000 Pa·s or more. From the viewpoint of low-temperature fixability, the complex viscosity of the toner at 110°C is preferably 2000 Pa·s or less, more preferably 1500 Pa·s or less, and even more preferably 1000 Pa·s or less. On the other hand, from the viewpoint of print image strength, the complex viscosity at 110°C is preferably 400 Pa·s or more, and 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.

[0040] Methods for adjusting the complex viscosity of the present toner to fall within the preferred range include, for example, taking the following measures (1) to (5) during the production of the present toner or in the component composition of the present toner: (1) Decreasing the molecular weight or crosslinking rate of the amorphous polyester; (2) Increasing the proportion of the core in the case of a core-shell toner; (3) Dispersing a crystalline polyester in the core; (4) Dispersing a wax with a low melting point in the core; (5) Dispersing a plasticizer in the core.

[0041] <Residual Rate> When 20 g of the toner is placed in a thermo-hygrostat at a temperature of 50°C and a relative humidity of 40%, and then passed through a 60-mesh sieve, the residual rate on the sieve is less than 5%. Having the residual rate within this range prevents a decrease in the strength of the printed image due to the brittleness of the binder resin when the toner is fixed. From the viewpoint of the strength of the printed image, the residual rate of the toner is preferably less than 5%, more preferably less than 1%, and even more preferably less than 0.5%. From the same viewpoint, it is most preferable that the residual rate is 0%, i.e., no toner remains on the sieve.

[0042] Methods for making the residual rate of the present toner less than the above upper limit include, for example, taking the following measures (1) to (5) during the production of the present toner or in the component composition of the present toner: (1) Increasing the molecular weight or crosslinking rate of the amorphous polyester; (2) Increasing the proportion of the shell in the case of a core-shell toner; (3) When dispersing a crystalline polyester in the core, selecting one that separates from the amorphous polyester for the core at room temperature; (4) Dispersing a wax with a high melting point in the core; (5) Increasing the amount of external additives.

[0043] <Mechanism> Toner melts and fuses to print media when heated to a certain temperature. However, to melt at lower temperatures, it must soften to a viscosity below a certain level even at low temperatures. On the other hand, if the overall viscosity of the toner is too low or soft components are unevenly distributed on the surface of toner particles, toner blocking and other problems are more likely to occur. Blocking is a phenomenon in which toner softens at a certain temperature, causing toner particles to adhere to each other. The occurrence of this phenomenon indicates that the binder resin is soft even at room temperature. Toner with extremely low resin viscosity exhibits poor adhesion between toner particles when printed, resulting in reduced print image strength. This toner contains an amorphous polyester resin and a crystalline polyester resin as the binder resin for the base particles. Even when the amorphous polyester resin is softened to a certain viscosity, the presence of intramolecular hydrogen bonds strengthens the molecular bonds, resulting in increased adhesion between toner particles, thereby preventing a decrease in print image strength. Furthermore, when an amorphous polyester resin and a crystalline polyester resin are used in combination, the crystalline polyester resin has a sharp melting property, which makes it compatible with the amorphous polyester resin, making it possible to rapidly reduce the viscosity of the toner. In other words, it is believed that by using an amorphous polyester resin and a crystalline polyester resin in combination, it is possible to improve the fixability in a specific temperature range without lowering the viscosity of the amorphous polyester resin more than necessary. Furthermore, when the toner base particles have a core-shell structure, it becomes easier to balance low-temperature fixability and printed image strength. Furthermore, this toner uses the above-mentioned amorphous polyester resin and crystalline polyester resin, 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. When 20 g of the toner is placed in a thermo-hygrostat kept at a temperature of 50°C and a relative humidity of 40%, and is held there for 20 hours, and then sieved, the remaining percentage on the sieve is less than 5%.By setting the complex viscosities at 80°C and 110°C within the above ranges, the toner can be fixed at low fixing temperatures (100°C or less) 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 less, and has sufficient adhesion to film media, which is thought to result in a toner that has sufficient fixability even in the low temperature range. Furthermore, by setting the residual rate below a certain value, the toner particles have a certain degree of viscosity, i.e., strength, even at room temperature after fixing, and adhesion between toner particles in the printed image is ensured, which is thought to result in a toner that is advantageous in adhesion tests and abrasion resistance tests of printed images.

[0044] <Environmental Impact> Toners for developing electrostatic images in commercial label printing machines and other applications often require low-temperature fixability and low environmental impact. In food packaging applications, environmental hormones, which disrupt the natural hormonal functions of living organisms, are particularly problematic. Polyester toners typically use bisphenol A derivatives 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 activity (estrogen: female hormone) and has been shown to specifically bind to and activate specific receptors. In recent years, there has been a growing movement around the world to restrict its use as an endocrine disruptor and environmental hormone. 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 human toxicity (respiratory sensitization). Furthermore, it is desirable to minimize heavy metal contamination from heavy metal catalysts used as catalysts for polyester resins.

[0045] For these reasons, the total content of bisphenol A and other compounds having a bisphenol structure in the present toner is preferably less than 100 ppm, more preferably less than 50 ppm, and even more preferably less than 10 ppm. Therefore, in producing the present toner, it is preferable to minimize the use of bisphenol A and other compounds having a bisphenol structure. Examples of other compounds having a bisphenol structure include alkylene oxide adducts of bisphenol A. In particular, ethylene oxide adducts (EO adducts) and propylene oxide adducts (PO adducts) are often used as polyester resin monomers for toners. The total content of bisphenol A and other compounds having a bisphenol structure, such as bisphenol A (EO adducts) and bisphenol A (PO adducts), in the present toner is measured by the method described in the Examples section below.

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

[0047] 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 using antimony, tin, and other heavy metal components as much as possible. The total content of tin and antimony in the present toner is measured by the method described in the Examples section below.

[0048] <Toner Base Particles> The base particles of the toner of the present invention (hereinafter also referred to as "toner base particles of the present invention") contain an amorphous polyester resin and a crystalline polyester resin. In order to further enjoy the effects of the present invention, the toner base particles of the present invention preferably have a core-shell structure, and more preferably contain an amorphous polyester resin and a crystalline polyester as the binder resin of the core, and contain an amorphous polyester resin as the binder resin of the shell.

[0049] 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. The core-shell structure is not limited to a structure in which the core component is completely covered with the shell component. The core-shell structure may be one in which the surface of the core component is partially exposed, or may be one in which the surface of the core component is partially dispersed in the shell component.

[0050] 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. The shell component may cover the core component continuously or discontinuously.

[0051] When toner base particles are prepared 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 (a method for controlling polarity), and the other is to add the 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 for thermodynamically arranging the shell particles at the interface between the core components and the wet medium (a method for controlling polarity) and the method for adding the shell particles after the core components and physically arrange them on the surface of the core components.

[0052] When adding the shell fine particles after the core component, a method of adding the shell fine particles after the composition and / or shape of the core component is determined (the shape, physical properties, compatibility, etc. of the core component may change due to subsequent heating, aging, stirring, etc.) may also be used.

[0053] 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.

[0054] <Amorphous polyester resin> The amorphous polyester resin refers to a polyester resin that exhibits amorphous properties and has a glass transition point (Tg) but no melting point, i.e., no clear endothermic peak upon heating, in an endothermic curve obtained by differential scanning calorimetry (DSC).

[0055] The amorphous polyester resin is obtained by polycondensation reaction of polycarboxylic acid monomers (derivatives) and polyhydric alcohol monomers (derivatives) in the presence of a suitable polymerization catalyst. Examples of the polycarboxylic acid monomer derivatives include alkyl esters, acid anhydrides, and acid chlorides of polycarboxylic acid monomers. Examples of the polyhydric alcohol monomer derivatives include esters of polyhydric alcohol monomers and hydroxycarboxylic acids.

[0056] Examples of polycarboxylic acid monomers include oxalic acid, succinic acid, maleic acid, adipic acid, β-methyladipic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, fumaric acid, citraconic acid, diglycolic acid, cyclohexane-3,5-diene-1,2-dicarboxylic acid, malic acid, citric acid, hexahydroterephthalic acid, malonic acid, pimelic acid, tartaric acid, mucic acid, phthalic acid, isophthalic acid, terephthalic acid, tetrachlorophthalic acid, chlorophthalic acid, nitrophthalic acid, p-calcium phosphate, methyl phthalic acid ... Examples of suitable dicarboxylic acids include dicarboxylic acids such as carboxyphenylacetic acid, p-phenylenediacetic acid, m-phenylenediglycolic acid, p-phenylenediglycolic acid, o-phenylenediglycolic acid, diphenylacetic acid, diphenyl-p,p'-dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, anthracenedicarboxylic acid, and dodecenylsuccinic acid; and tricarboxylic acids or higher such as naphthalenetricarboxylic acid, naphthalenetetracarboxylic acid, pyrenetricarboxylic acid, and pyrenetetracarboxylic acid. These may be used alone or in combination of two or more. Among these, from the viewpoints of toner storage stability, handleability, cost, and supply amount, preferred dicarboxylic acids are maleic acid, adipic acid, fumaric acid, cyclohexane-3,5-diene-1,2-dicarboxylic acid, isophthalic acid, and terephthalic acid, with adipic acid, isophthalic acid, and terephthalic acid being more preferred, and isophthalic acid and terephthalic acid being even more preferred.

[0057] Examples of polyhydric alcohol monomers include aliphatic polyhydric alcohol monomers (aliphatic polyhydric alcohol monomers, alicyclic polyhydric alcohol monomers), aromatic polyhydric alcohol monomers, etc. Among them, aliphatic polyhydric alcohols are preferred in terms of being able to reduce the melt viscosity when the molecular weight is increased.

[0058] Examples of aliphatic polyhydric alcohol monomers include dihydric alcohols such as ethylene glycol, neopentyl glycol, propylene glycol, butanediol, diethylene glycol, hexanediol, cyclohexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, octanediol, decanediol, dodecanediol, 1,4-benzenediol, and 1,3-benzenediol; and trihydric or higher alcohols (polyols) such as glycerin, pentaerythritol, trimethylolpropane, hexamethylolmelamine, hexaethylolmelamine, tetramethylolbenzoguanamine, tetraethylolbenzoguanamine, and 1,2,4-trihydroxybenzene. These may be used alone or in combination of two or more.

[0059] Among these, as dihydric alcohols, from the viewpoints of reducing the colorability of the resin, ease of raw material availability, and charging properties, ethylene glycol, neopentyl glycol, 1,4-cyclohexanedimethanol, and propylene glycol are preferred, with ethylene glycol and neopentyl glycol being more preferred, and ethylene glycol being even more preferred. As trihydric or higher alcohols, from the viewpoint of ease of adjusting the polymerization rate, glycerin, pentaerythritol, and trimethylolpropane are preferred, with trimethylolpropane being more preferred. Use of the above-mentioned aliphatic polyhydric alcohols is preferred in that it allows for lower viscosity without excessively reducing the molecular weight of the amorphous polyester resin compared to the use of aromatic polyhydric alcohols. This makes it possible to achieve low-temperature fixation while preventing a decrease in image strength of printed matter due to a decrease in molecular weight, thereby further enjoying the effects of the present invention.

[0060] In order to achieve a higher level of balance between viscosity characteristics and charging characteristics, the amorphous polyester resin preferably uses two or more aliphatic polyhydric alcohol monomers as the polyhydric alcohol monomer, and particularly preferably contains the above-mentioned dihydric alcohol and trihydric or higher alcohol. When the total moles of the dihydric alcohol and trihydric or higher alcohol in the polyhydric alcohol monomer is 100, the molar ratio of the dihydric alcohol to the trihydric or higher alcohol (dihydric alcohol / trihydric or higher alcohol) is preferably 50 / 50 to 99.9 / 0.1, more preferably 80 / 20 to 99.5 / 0.5, and even more preferably 90 / 10 to 99 / 1.

[0061] Furthermore, from the viewpoint of expecting improved storage stability as a result of increasing affinity with the crystalline polyester and making it easier to retain the crystalline polyester inside the toner base particles, it is preferable to include an aliphatic polyhydric alcohol having a branched chain structure, such as neopentyl glycol or propylene glycol, particularly an aliphatic dihydric alcohol, as the dihydric alcohol. From the above viewpoints, the content of the aliphatic polyhydric alcohol having a branched chain structure, particularly an aliphatic dihydric alcohol, in the polyhydric alcohol monomer is preferably 1 to 80 mol %, more preferably 10 to 70 mol %, and even more preferably 20 to 60 mol %.

[0062] The ratio of the polycarboxylic acid monomer (derivative) and the polyhydric alcohol monomer (derivative) to be subjected to the polycondensation reaction is preferably such that the equivalent ratio (OH) / (COOH) of the hydroxy group (OH) of the polyhydric alcohol to the carboxy group (COOH) of the polycarboxylic acid is within the range of 1.5 / 1 to 1 / 1.5.

[0063] From the viewpoint of achieving both strength of the printed image and low-temperature fixability, the glass transition temperature (Tg) of the amorphous polyester resin is preferably in the range of 45° C. to 65° C. The more preferable range of the glass transition temperature (Tg) of the amorphous polyester resin for the core application is slightly different from that for the shell application, as described below.

[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 equal to or higher than the lower limit, the image strength of the printed matter is maintained. If the glass transition temperature of the amorphous polyester resin is equal to or lower than the upper limit, the target low-temperature fixability can be achieved by combining it with an appropriate crystalline polyester. The glass transition temperature of the amorphous polyester resin for core use is more preferably 50°C or higher, even more preferably 53°C or higher, and is 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 in 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 of the amorphous polyester resin used for the shell is more preferably 54°C or higher, even more preferably 58°C or higher, and more preferably 62°C or lower.

[0066] The present toner may contain an amorphous polyester resin having a glass transition temperature of more than 65°C, particularly more than 70°C, within a range that does not impair the low-temperature fixability of the toner. However, when an amorphous polyester resin having a glass transition temperature of more than 70°C is contained, the content of the amorphous polyester resin having a glass transition temperature of 70°C or higher relative to the total mass of the present toner is preferably less than 30% by mass, more preferably less than 20% by mass, even more preferably less than 10% by mass, even more preferably less than 5% by mass, particularly preferably less than 1% by mass, and most preferably zero. In particular, the content of the crystalline polyester resin having a glass transition temperature of 70°C or higher relative to the total mass of the present toner is preferably less than 5% by mass, less than 1% by mass, and most preferably zero. When the present toner does not contain an amorphous polyester resin having a glass transition temperature of 70°C or higher, no glass transition peak is detected in the temperature range of 70°C or higher when measured using a differential scanning calorimeter (DSC). Examples of amorphous polyester resins having a glass transition temperature of 70°C or higher include polyethylene terephthalate (PET), which uses terephthalic acid as the dicarboxylic acid component and ethylene glycol as the aliphatic dialcohol component, and polybutylene terephthalate (PBT), which uses terephthalic acid as the dicarboxylic acid component and 1,4-butanediol as the aliphatic dialcohol component. That is, the amorphous polyester resin contained in the present toner is preferably composed of a polyester resin other than PET or PBT. Furthermore, the present toner preferably does not have a glass transition peak in a temperature range of 70°C or higher in DSC, and more preferably does not have a glass transition peak in a temperature range of 65°C or higher.

[0067] The glass transition temperature of the amorphous polyester resin is measured by the method described in the Examples section below.

[0068] The softening temperature of the amorphous polyester resin for core use is preferably in the range of 95 to 130°C. If the softening temperature is 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 of the amorphous polyester resin for core use is more preferably 100°C or higher, even more preferably 105°C or higher, and is more preferably 125°C or lower, even more preferably 120°C or lower.

[0069] 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 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 target low-temperature fixability can be achieved by combining it with an appropriate crystalline polyester. The softening temperature of the amorphous polyester resin used for the shell is more preferably 110°C or higher, even more preferably 115°C or higher, and is more preferably 135°C or lower, even more preferably 130°C or lower.

[0070] The softening temperature of the amorphous polyester resin is measured by the method described in the Examples section below.

[0071] 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 above lower limit, sufficient stability can be obtained for use as a polyester dispersion in the aggregation step when preparing toner base particles. On the other hand, an acid value of 20 mgKOH / g or less is preferred from the viewpoint of ease of preparation of aggregated particles. If the acid value is higher than 20 mgKOH / g, the dispersion tends to be highly stable and aggregation tends to be difficult. The acid value of the amorphous polyester resin is more preferably 5 mgKOH / g or more, even more preferably 6 mgKOH / g or more, and more preferably 18 mgKOH / g or less, even more preferably 15 mgKOH / g or less.

[0072] The acid value of the amorphous polyester resin is measured by the method described in the Examples section below.

[0073] 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). When the weight average molecular weight (Mw) of the amorphous polyester resin is 5,000 or more, high image strength can be obtained. When the weight average molecular weight (Mw) of the amorphous polyester resin is 30,000 or less, the complex viscosity can be reduced. The method for measuring the weight average molecular weight (Mw) of the amorphous polyester resin is as described in the Examples section below.

[0074] The toner base particles may contain only one type of amorphous polyester resin in each of the core and the shell, or may contain two or more types of amorphous polyester resins with different monomer compositions, physical properties, etc. The amorphous polyester resin in the core and the amorphous polyester resin in the shell may be the same or different.

[0075] 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.

[0076] 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 can be 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 can be 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.

[0077] The total content of the amorphous polyester resin in the toner base particles is preferably 65% ​​by mass or more and 90% by mass or less, based on the total mass of the toner base particles. If the total content of the amorphous polyester resin in the toner base particles is 65% by mass or more, a toner with excellent fixability to printed matter can be obtained. From this perspective, the total content of the amorphous polyester resin in the toner base particles is particularly preferably 70% by mass or more, and even more preferably 75% by mass or more. On the other hand, if the total content of the amorphous polyester resin in the toner base particles is 90% by mass or less, it is possible to add a sufficient amount of wax or crystalline polyester to achieve functionality. From this perspective, the total content of the amorphous polyester resin in the toner base particles is particularly preferably 85% by mass or less, and even more preferably 80% by mass or less.

[0078] <Crystalline Polyester Resin> The crystalline polyester resin means a polyester resin that has a crystalline melting peak when measured with a differential scanning calorimeter (DSC).

[0079] The crystalline polyester resin is obtained by a polycondensation reaction of a dicarboxylic acid monomer (including a derivative thereof; hereinafter, sometimes referred to as a "dicarboxylic acid component") and an aliphatic dialcohol monomer (including a derivative thereof; hereinafter, sometimes referred to as an "aliphatic dialcohol component") as raw materials in the presence of an appropriate polymerization catalyst.

[0080] 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, from the viewpoint of controlling crystallinity and melting point, adipic acid, sebacic acid, and dodecanedioic acid are preferred, adipic acid and sebacic acid are more preferred, and sebacic acid is even more preferred. These dicarboxylic acid components may be used alone or in combination.

[0081] The aliphatic dialcohol component is not particularly limited, and examples thereof include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,15-pentadecanediol, and 1,16-hexadecanediol. Among these, from the viewpoints of crystallinity control and melting point control, ethylene glycol, 1,3-propanediol, and 1,6-hexanediol are preferred, ethylene glycol and 1,6-hexanediol are more preferred, and ethylene glycol is even more preferred. These aliphatic alcohol components may be used alone or in combination.

[0082] 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.

[0083] The melting point (Tm) of the crystalline polyester resin is preferably in the range of 62 to 90°C. If the melting point is equal to or higher than the lower limit, significant blocking of toner particles does not occur, and image strength is maintained. If the melting point is equal to or lower than the upper limit, excellent low-temperature fixability can be achieved by adding an appropriate amount of crystalline polyester resin. The method for adjusting the melting point (Tm) of the crystalline polyester resin is not particularly limited, but examples include adjusting the combination of dicarboxylic acid components and aliphatic dialcohol components used, or appropriately adjusting the molecular weight, degree of crystallinity, etc.

[0084] The present toner may contain a crystalline polyester resin having a melting point of over 90°C to the extent that the low-temperature fixability of the toner is not impaired. When a crystalline polyester resin having a melting point of over 90°C is contained, the content of the crystalline polyester resin having a melting point of 90°C or higher relative to the total mass of the present toner is preferably less than 30% by mass, more preferably less than 20% by mass, even more preferably less than 10% by mass, even more preferably less than 5% by mass, particularly preferably less than 1% by mass, and most preferably zero. In particular, the content of the crystalline polyester resin having a melting point of 200°C or higher relative to the total mass of the present toner is preferably less than 5% by mass, less than 1% by mass, and most preferably zero. When the present toner does not contain a crystalline polyester resin having a melting point of 200°C or higher, no crystalline melting peak is detected in the temperature range of 200°C or higher in measurement by differential scanning calorimetry (DSC). Examples of crystalline polyester resins having a melting point of 200°C or higher include polyethylene terephthalate (PET), which uses terephthalic acid as the dicarboxylic acid component and ethylene glycol as the aliphatic dialcohol component, and polybutylene terephthalate (PBT), which uses terephthalic acid as the dicarboxylic acid component and 1,4-butanediol as the aliphatic dialcohol component. In other words, the crystalline polyester resin contained in the present toner is preferably composed of a polyester resin other than PET or PBT. Furthermore, the present toner preferably does not have a crystalline melting peak in a temperature range of 200°C or higher in DSC, and more preferably does not have a crystalline melting peak in a temperature range of 90°C or higher.

[0085] The acid value of the crystalline polyester resin is preferably 80 mgKOH / g or less from the viewpoint of ease of preparation of aggregated particles. If the acid value is higher than 80 mgKOH / g, the dispersion liquid is highly stable and aggregation is difficult. The acid value of the crystalline polyester resin is more preferably 75 mgKOH / g or less, and even more preferably 70 mgKOH / g or less.

[0086] The acid value of the crystalline polyester resin is measured by the method described in the Examples section below.

[0087] 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.

[0088] 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.

[0089] From the viewpoint of the balance between complex viscosity and residual rate, the content ratio of the amorphous polyester resin to the crystalline polyester resin constituting the core, relative to a total of 100 parts by mass, is preferably amorphous polyester resin:crystalline polyester resin (mass ratio) = 97:3 to 80:20, more preferably 95:5 to 85:15, and even more preferably 93:7 to 90:10.

[0090] As described above, a toner containing a crystalline polyester resin exhibits a clear crystalline melting peak derived from the crystalline polyester when measured by DSC. This melting peak in a toner may appear at a temperature different from the melting peak of the crystalline polyester resin alone, depending on the degree of compatibility with the binder resin component in the toner, i.e., the amorphous polyester resin. Furthermore, this melting peak is observed during the first temperature rise in DSC measurement, but is not observed during re-heating after cooling to room temperature after once heating. This is because the crystalline polyester resin is completely compatible with the amorphous polyester resin, which is the binder resin in the toner, when melted, and is also the principle behind the addition of a crystalline polyester resin to reduce the viscosity of the toner. Therefore, whether or not a toner contains a crystalline polyester resin can be confirmed by observing a melting peak during the first temperature rise and disappearing during the second temperature rise in DSC measurement.

[0091] <Method for Producing Polyester Resin> The method for producing polyester resins, which are crystalline polyester resins and amorphous polyester resins, 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, to carry out an esterification reaction or an ester exchange reaction, and water or alcohol generated by the reaction is removed. Subsequently, a polycondensation reaction is carried out, during which the pressure inside the reaction vessel is gradually reduced, and polycondensation is carried out while distilling off the alcohol component under a vacuum of 150 mmHg (20 kPa) or less, preferably 15 mmHg (2 kPa) or less.

[0092] 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. Among these, titanium-based catalysts are preferred because they make it easier to obtain polyester resins with reduced VOC total content (TVOC: Total Volatile Organic Compound). As mentioned above, the toner of the present invention preferably has a total antimony and tin content of less than 1,000 ppm, and therefore it is not preferable to use tin-based catalysts or antimony trioxide as the catalyst.

[0093] Examples of titanium catalysts include titanium alkoxide compounds having an alkoxy group, titanium carboxylate compounds, titanyl carboxylate, titanyl carboxylate salts, titanium chelate compounds, etc. Examples of titanium alkoxide compounds having an alkoxy group include tetramethoxytitanium, tetraethoxytitanium, tetrapropoxytitanium, tetrabutoxytitanium, tetrapentoxytitanium, tetraoctoxytitanium, etc. Examples of titanium carboxylate compounds include titanium formate, titanium acetate, titanium propionate, titanium octanoate, titanium oxalate, titanium succinate, titanium maleate, titanium adipate, titanium sebacate, titanium hexanetricarboxylate, titanium isooctanetricarboxylate, titanium octanetetracarboxylate, titanium decanetetracarboxylate, titanium benzoate, titanium phthalate, titanium terephthalate, titanium isophthalate, titanium 1,3-naphthalenedicarboxylate, titanium 4,4-biphenyldicarboxylate, titanium 2,5-toluenedicarboxylate, titanium anthracenedicarboxylate, titanium trimellitate, titanium 2,4,6-naphthalenetricarboxylate, titanium pyromellitate, and titanium 2,3,4,6-naphthalenetetracarboxylate. Of these, tetrabutoxytitanium is preferred. Titanium-based catalysts may be used alone or in combination of two or more.

[0094] <Colorant> The toner may contain a colorant. Any known colorant can be used as the colorant contained in the toner. 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, triarylmethane dyes, monoazo dyes, disazo dyes, and condensed azo dyes and pigments, and any known dyes and pigments can be used alone or in combination.

[0095] 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. The following toner set combinations are preferred: The magenta toner preferably contains a quinacridone-based dyes and pigments and / or monoazo-based dyes and pigments. The black toner preferably contains carbon black. The cyan toner preferably contains a copper phthalocyanine-based dyes and pigments. The yellow toner preferably contains at least one dyes and pigments selected from monoazo-, disazo-, and condensed azo-based dyes and pigments.

[0096] Specifically, for cyan, C.I. Pigment Blue 15:3, C.I. Pigment Blue 15:4; for yellow, C.I. Pigment Yellow 74, C.I. Pigment Yellow 83 which is a disazo dye / pigment, C.I. Pigment Yellow 93 which is a condensed azo dye / pigment, C.I. Pigment Yellow 155, C.I. Pigment Yellow 180, C.I. Pigment Yellow 185; for magenta, C.I. Pigment Red 48:1, C.I. Pigment Red 53:1, C.I. Pigment Red 57:1, C.I. Pigment Red 5, C.I. Pigment Red 122 which is a quinacridone dye / pigment, C.I. Pigment Red 209, and C.I. Pigment Red 122 which is a monoazo dye / pigment. Pigment Red 269 (238), and the like.

[0097] 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.

[0098] <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. 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.

[0099] The type of wax contained in the present toner is not limited, but it is preferable that the toner contains an ester wax.

[0100] (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 primarily containing C18 and / or C22 hydrocarbons are more preferred, and among these, behenyl behenate, stearyl behenate, behenyl stearate, and waxes primarily containing 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 per molecule of the ester wax is preferably 36 or more, more preferably 40 or more. On the other hand, from the viewpoint of low-temperature fixation, the number of carbon atoms per 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.

[0101] (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; and the like. Preferred examples include hydrocarbon waxes such as paraffin wax and Fischer-Tropsch wax; and silicone waxes.

[0102] (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.

[0103] <Charge Control Agent> The 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 for positive charging include nigrosine dyes, amino group-containing vinyl copolymers, quaternary ammonium salt compounds, polyamine resins, etc. Specific examples of charge control agents for negative charging include metal-containing azo dyes containing metals such as chromium, zinc, iron, cobalt, and aluminum, and salts and metal complexes of salicylic acid or alkylsalicylic acid with the above metals.

[0104] The amount of the charge control agent is preferably 0.1 to 25% by mass, and 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.

[0105] <External Additive> The present 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.

[0106] 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.

[0107] The external additive may be selected from various inorganic or organic fine particles and used. Two or more types of external additives may be used in combination.

[0108] 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.

[0109] As the organic fine particles, fine particles of styrene-based resin, acrylic-based resin, epoxy-based resin, melamine-based resin, etc. Also, the charging stability can be improved by using fine particles containing fluorine atoms.

[0110] Among these external additives, silica, titanium oxide, alumina, zinc oxide, various carbon blacks, conductive carbon blacks, etc. are particularly suitable.

[0111] The external additive may be the inorganic or organic fine particles whose surfaces have been subjected to a surface treatment such as hydrophobization with a treatment agent such as a silane coupling agent such as hexamethyldisilazane (HMDS) or dimethyldichlorosilane (DMDS), a titanate-based coupling agent, a silicone oil treatment agent such as 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 may also be used in combination.

[0112] 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, based on 100 parts by mass of the toner base particles.

[0113] In the present toner, conductive fine particles may be used as an external additive from the viewpoint of charge control. 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 in which a polymer having conjugated double bonds such as polyacetylene, polyphenylacetylene, and poly-p-phenylene is doped with a conductive substance such as a metal; and carbon such as carbon black and graphite. From the viewpoint of imparting conductivity without impairing the fluidity of the toner, conductive fine particles such as conductive titanium oxide or those doped with a conductive substance are more preferred.

[0114] 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.

[0115] <Form of the Toner> From the viewpoint of image reproducibility and toner consumption, the volume median particle diameter (Dv50) of the toner is preferably 7.0 μm or less, more preferably 6.5 μm or less, and even more preferably 6.3 μm or less. On the other hand, from the viewpoint of environmental safety against dust, the volume median particle diameter (Dv50) of the toner is preferably 3.0 μm or more, more preferably 4.0 μm or more, even more preferably 4.5 μm or more, even more preferably 5.0 μm or more, even more preferably 5.5 μm or more, and even more preferably 6.0 μm or more. In the present invention, the "volume median particle diameter (Dv50)" is measured by the method described in the Examples section below and is defined as the value measured in this manner. Furthermore, the volume median particle diameter (Dv50) is defined as the value measured on toner particles finally obtained in a manufacturing process comprising toner base particles and external additives.

[0116] The shape of the toner of the present invention has an average circularity of preferably 0.92 or more, more preferably 0.95 or more, and even more preferably 0.96 or more, as measured using a flow particle image analyzer FPIA-3000 (manufactured by Malvern Instruments). On the other hand, the average circularity is preferably 0.99 or less, more preferably 0.98 or less, and even more preferably 0.97 or less.

[0117] [Method for Producing Toner] 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.

[0118] <Method for producing 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 binder resin fine particles with, as needed, 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 binder resin with an aqueous medium. From the viewpoint that aggregating particles using an aqueous emulsion aggregation method makes it easier to control the circularity of the final base particles, it is preferable to obtain polyester resin fine particles as an aqueous emulsion by emulsification.

[0119] (Method of obtaining a binder resin and then mixing it with an aqueous medium to emulsify) After obtaining a binder resin by any polymerization method, the binder resin is mixed with an aqueous medium and emulsified by applying a shear force, thereby obtaining primary polymer particles of the binder resin.

[0120] Examples of emulsifiers for applying shear force include homogenizers, homomixers, pressure kneaders, extruders, media dispersers, etc. If the viscosity of the binder resin during emulsification is high and the primary resin particles do not become small enough to reach the desired particle size, an emulsifier capable of applying pressure equal to or higher than atmospheric pressure can be used to raise the temperature to the higher of either the melting point or the glass transition temperature of the resin, thereby emulsifying the resin in a state where the viscosity of the resin is reduced, thereby obtaining primary particles of the desired particle size.

[0121] Another method for reducing the resin viscosity may involve mixing an organic solvent into the binder resin in advance. The organic solvent used is not particularly limited as long as it dissolves the polyester resin, but examples 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 water or the resin for the purposes of improving affinity with the aqueous medium and controlling the particle size distribution. When an organic solvent is added, it is necessary to remove the organic solvent 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.

[0122] 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.

[0123] As the emulsifier, any known emulsifier can be used, but one or more emulsifiers selected from cationic surfactants, anionic surfactants, and nonionic surfactants can be used in combination. Among them, anionic surfactants are preferred from the viewpoints of ease of particle preparation, washability, and waste liquid treatment.

[0124] Examples of cationic surfactants include dodecyl ammonium chloride, dodecyl ammonium bromide, dodecyl trimethyl ammonium bromide, dodecyl pyridinium chloride, dodecyl pyridinium bromide, and hexadecyl trimethyl ammonium bromide.

[0125] Examples of anionic surfactants include fatty acid soaps such as sodium stearate and sodium dodecanoate, sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and sodium lauryl sulfate.

[0126] Examples of nonionic surfactants include polyoxyethylene dodecyl ether, polyoxyethylene hexadecyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl ether, polyoxyethylene sorbitan monooleate ether, and monodecanoyl sucrose.

[0127] Examples of dispersants include water-soluble polymers such as polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, and sodium polyacrylate; and inorganic compounds such as tricalcium phosphate, aluminum hydroxide, calcium sulfate, calcium carbonate, and barium carbonate.

[0128] The amount of the emulsifier and dispersant used is preferably 0.01 to 20 parts by mass per 100 parts by mass of the binder resin.

[0129] 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.

[0130] (Particle size of primary polymer particles of binder resin) The median diameter (D50) of the primary polymer particles of the binder resin (hereinafter also referred to as primary resin particles) is preferably 100 nm or more, more preferably 150 nm or more, and even more preferably 180 nm or more. On the other hand, the median diameter (D50) of the primary resin particles 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.

[0131] (Aggregation Step) 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 each component 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.

[0132] 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.

[0133] 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.

[0134] 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 thereof may be used. In order to increase the stability of the particle aggregates having a core-shell structure obtained in the aggregation step, it is preferable to fuse the aggregated particles in the aging step after the aggregation step.

[0135] The colorant particles are preferably used in a state of being 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.

[0136] 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.

[0137] When an electrolyte is added to perform coagulation, the electrolyte may be any of an acid, an alkali, and 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 NaCl, KCl, LiCl, and Na ２ SO ４ , K. ２ SO ４ , Li ２ SO ４ , MgCl ２ , CaCl ２ , MgSO ４ , CaSO ４ , ZnSO ４ , Al ２ (SO ４ ) ３ , Fe ２ (SO ４ ) ３ , C.H. ３ COONa, C ６ H ５ SO ３ Among these, inorganic salts having a polyvalent metal cation of divalent or higher are preferred.

[0138] 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, per 100 parts by mass of the solid components of the mixed dispersion. The amount of electrolyte added 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. The aggregation temperature when the electrolyte is added to aggregate is preferably 20° C. or more, particularly preferably 30° C. or more, and preferably 70° C. or less, particularly preferably 60° C. or less.

[0139] 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.

[0140] (Aging Step) 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 a temperature 5°C higher than the Tg of the primary particles of the shell binder resin. 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.

[0141] 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 when producing primary resin particles. In particular, it is preferable to use the same emulsifier as used when producing the primary particles.

[0142] When a surfactant is added, the amount 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 or less, relative to 100 parts by mass of the solid components of the mixed dispersion.

[0143] After the aggregation step, by adding a surfactant or adjusting the pH before the completion of the aging step, it is possible to suppress aggregation of the particle aggregates obtained in the aggregation step, and it may be possible to suppress the generation of coarse particles in the aging step.

[0144] 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.

[0145] <Method of Adding External Additives> Examples of methods for adding external additives include a method using a high-speed agitator such as a Henschel mixer, and a method using a device capable of applying compressive shear stress. The toner can be produced by a single-stage external addition method in which all external additives are added to the toner base particles at the same time. The toner can also be produced by a separate-stage external addition method in which external additives are added separately. In order to prevent a temperature rise during external addition, a cooling device can be installed in the container, or separate-stage external addition can be performed.

[0146] [Use Form] The present toner may be used in either the form of a two-component developer in which the toner is used together with a carrier, or a magnetic or non-magnetic one-component developer in which no carrier is used.

[0147] 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.

[0148] [Cartridge / Image Forming Apparatus] Next, an embodiment of an image forming apparatus (image forming apparatus of the present invention) using the toner 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.

[0149] 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.

[0150] The electrophotographic photoreceptor is not particularly limited, and for example, a drum-shaped photoreceptor having the above-described photosensitive layer formed on the surface of a cylindrical conductive support can be used. The charging device uniformly charges the surface of the electrophotographic photoreceptor to a predetermined potential. Common charging devices include non-contact corona charging devices such as corotrons and scorotrons, and contact charging devices.

[0151] The exposure device is not particularly limited in type as long as it can expose the electrophotographic photosensitive member to light and 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 toner charge potential, thereby transferring the toner image formed on the electrophotographic photosensitive member to recording paper (paper, medium). The transfer device is not particularly limited in type, and devices 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 be omitted. The cleaning device is not particularly limited, and any cleaning device, such as a brush cleaner, magnetic roller cleaner, or blade cleaner, can be used.

[0152] In the image forming apparatus configured as above, an image is recorded as follows.

[0153] First, the surface (photosensitive surface) of the electrophotographic photosensitive member 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 a DC voltage. Next, the charged photosensitive surface of the electrophotographic photosensitive member is exposed to light by an exposure device according to the image to be recorded, and an electrostatic latent image is formed on the photosensitive surface. Then, the electrostatic latent image formed on the photosensitive surface of the electrophotographic photosensitive member is developed by a developing device. In the developing device, the toner is formed into a thin layer by a regulating member such as a developing blade, and is triboelectrically charged to a predetermined polarity, and is carried on a developing roller while being transported and brought into contact with the surface of the electrophotographic photosensitive member.

[0154] 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 to recording paper or the like by a transfer device. After this, toner remaining on the photosensitive surface of the electrophotographic photosensitive member without being transferred is removed by a cleaning device. After the toner image is transferred to a print medium such as recording paper, the toner image is thermally fixed to the print medium such as recording paper by passing it through a fixing device, thereby obtaining a final image. Note that the image forming apparatus may be configured to be capable of performing, for example, a static elimination process in addition to the above-described configuration. The static elimination process is a process of eliminating static electricity from the electrophotographic photosensitive member by exposing the electrophotographic photosensitive member to light.

[0155] The image forming apparatus may be further modified and configured, for example, to be capable of performing processes such as a pre-exposure process and an auxiliary charging process, to be configured to perform offset printing, or to be configured as a full-color tandem system using multiple types of toner.

[0156] 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 apparatus such as a copier or a laser beam printer. The present toner is applied to this toner cartridge, thereby constituting the toner cartridge of the present invention.

[0157] [Printing Medium] There are no particular limitations on the printing medium on which printing is performed using the present toner, and it may be any medium generally used in image forming devices, such as 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 present toner has excellent low-temperature fixability, it is effective when the printing medium is a plastic film, which requires even greater low-temperature fixability.

[0158] The present invention will be explained in more detail below with reference to examples. However, the present invention is not limited to the following examples as long as it does not depart from the gist of the present invention. In the following examples and comparative examples, "parts" simply means "parts by mass."

[0159] The methods for measuring various physical properties are as follows.

[0160] <Median 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, under the following measurement conditions: solvent refractive index: 1.333, measurement time: 120 seconds, number of measurements: 5, according to the method described in the instruction manual, and the average value was calculated. Other setting conditions were particle refractive index: 1.59, transmittance: transparent, shape: spherical, and density: 1.04.

[0161] <Volume Median Particle Size (Dv50)> The volume median particle size (Dv50) was measured using a Multisizer III (aperture diameter: 100 μm or less, abbreviated as Multisizer) manufactured by Beckman Coulter. Isoton II manufactured by the same company was used as a dispersion medium, and the dispersion was dispersed so that the dispersoid concentration was 0.03 mass %. The measurement results were shown as "volume particle size."

[0162] <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.

[0163] <Weight average molecular weight (Mw)> The Mw of the polyester resin was determined by GPC from the retention time corresponding to the peak value of the obtained elution curve, in terms of standard styrene. Apparatus: GPC apparatus HLC-8320 manufactured by Tosoh Corporation Column: TOSOH TSKgel Super HM-H (diameter 6 m × length 150 mm × 2 columns) Solvent: THF Column temperature: 40°C Flow rate: 1 mL / min Sample concentration: 4 mg / 10 mg Calibration curve: Standard polystyrene

[0164] <Emulsion Solids Concentration> The emulsion solids 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.

[0165] <Glass Transition Temperature (Tg)> The glass transition temperature of the amorphous polyester resin was measured using a differential scanning calorimeter ("DSC-60" manufactured by Shimadzu Corporation) at a heating rate of 5°C / min, from the intersection of the baseline of the chart and the tangent to the endothermic curve. 10 mg±0.5 mg of the sample was weighed into an aluminum pan, melted at 100°C, which is equal to or higher than the glass transition temperature, for 10 minutes, and then rapidly cooled using dry ice.

[0166] <Softening Temperature (T4)> The softening temperature of the polyester resin was measured using a flow tester (manufactured by Shimadzu Corporation, "CFT-500D"), using a 1 mmφ×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 1.0 g of the resin sample flowed out was measured, and this was taken as the softening temperature.

[0167] <Melting Point (Tm)> The melting point of the crystalline polyester resin was measured using a differential scanning calorimeter ("DSC-60" manufactured by Shimadzu Corporation) at a heating rate of 5°C / min, and the temperature of the peak with the largest peak area among the endothermic peaks in the chart was taken as the melting point. 10 mg±0.5 mg of the sample was weighed into an aluminum pan, melted at 100°C, which is equal to or higher than the glass transition temperature, for 10 minutes, and then rapidly cooled using dry ice.

[0168] <Acid Value> The acid value of the polyester resin was measured as follows. Approximately 0.2 g of the measurement sample was accurately weighed (a(g)) into a side-arm Erlenmeyer flask, 20 mL of benzyl alcohol was added, and the sample was heated in a nitrogen atmosphere using a heater at 230°C for 15 minutes to dissolve the measurement 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 a 0.02 N KOH solution (titer amount = b(mL), titer of the KOH solution = p). A blank measurement was performed in the same manner (titer amount = c(mL)), and the acid value was calculated according to the following formula: Acid value (mgKOH / g) = {(b-c) x 0.02 x 56.11 x p} / a

[0169] <Quantitative Determination of Bisphenol A in Toner> The amount of bisphenol A remaining in the toner was measured by gas chromatography mass spectrometry (GC / MS). Details of the measurement method are described below. [Pretreatment] Bisphenol A-d16 (20 mg / L, 5 μL) was added to 0.01 g of a toner sample, and the mixture was dissolved in 5 mL of chloroform. 2 mL of methanol was added, and the mixture was extracted by shaking. This solution was concentrated by blowing nitrogen, and the sample was reprecipitated. The supernatant was then decanted, and the solvent was evaporated to dryness. The solution was then adjusted to volume with 1 mL of chloroform, and 50 μL of BSTFA (N,O-bis(trimethylsilyl)trifluoroacetamide) was added for derivatization. This solution was transferred to a vial, and measurement was performed by GC / MS. [Measurement conditions] (Apparatus) GC / MS: Agilent 7890B / 5977B manufactured by Agilent Technologies (GC) Column oven: 60°C (1 min) → 20°C / min → 325°C (20 min) Injection port: 280°C Injection volume: 1 μL Column: DB-17MS Length: 30 m, inner diameter: 250 μm, film thickness: 0.25 μm Column flow rate: 1.1 mL / min MSD transfer line: 290°C (MS) MS measurement mode: SIM m / z 357, 372, 368, 386 MS ion source: 230°C MS quadrupole: 150°C

[0170] <Quantification of Bisphenol A (EO Adduct) and Bisphenol A (PO Adduct) in Toner> The remaining amounts of bisphenol A (EO adduct) and bisphenol A (PO adduct) in the toner were measured by gas chromatography mass spectrometry (GC / MS). Details of the measurement method are described below. [Pretreatment] Bisphenol A-d16 (20 mg / L, 5 μL) was added to 0.01 g of a toner sample, and the mixture was dissolved in 5 mL of chloroform. 2 mL of methanol was added, and the mixture was extracted by shaking. This solution was concentrated by blowing nitrogen, and the sample was reprecipitated. The supernatant was then decanted, and the solvent was evaporated to dryness. The solution was then adjusted to volume with 1 mL of chloroform, and 50 μL of BSTFA (N,O-bis(trimethylsilyl)trifluoroacetamide) was added for derivatization. This solution was transferred to a vial, and measurement was performed by GC / MS. [Measurement conditions] (Apparatus) GC / MS: Agilent 7890B / 5977B manufactured by Agilent Technologies (GC) Column oven: 60°C (1 min) → 20°C / min → 325°C (20 min) Injection port: 280°C Injection volume: 1 μL Column: DB-17MS Length: 30 m, inner diameter: 250 μm, film thickness: 0.25 μm Column flow rate: 1.1 mL / min MSD transfer line: 290°C (MS) MS measurement mode: SIM m / z 445, 460, 489, 504, 368, 386 MS ion source: 230°C MS quadrupole: 150°C

[0171] <Quantification of Trimellitic Anhydride and Trimellitic Acid in Toner> [Pretreatment] 2 mL of methanol was added to 0.01 g of a toner sample, followed by ultrasonic extraction and concentration with nitrogen spray to a constant volume of 1 mL. This solution was transferred to a vial and measured using liquid chromatography tandem mass spectrometry (LC / MS / MS). [Measurement Conditions] (Apparatus) LC / MS / MS: Agilent 1260 / 6460 (LC) manufactured by Agilent Technologies, Inc. Column oven: 40°C Column: Inertsustain C18 (inner diameter 2.1 mm, length 10 cm, particle size 3 μm) Mobile phase A: 5 mM ammonium acetate aqueous solution Mobile phase B: methanol Flow rate: 0.2 mL / min Injection volume: 5 μL (MS / MS) Ion source: AJS ESI Mode: MRM Gradient: The gradient conditions shown in Table 1 were used.

[0172]

[0173] Gas temperature: 350°C Gas flow: 9 L / min Nebulizer: 50 psi Sheath gas temperature: 400°C Sheath gas flow: 10 L / min Capillary: -3000 V

[0174] <Quantitative Determination of Tin and Antimony in Toner> The quantitative determination of tin in the toner was carried out by ICP atomic emission spectrometry, and the quantitative determination of antimony in the toner was carried out by hydride generation atomic absorption spectrometry.

[0175] <Complex Viscosity> Complex viscosity was measured using an ARES rheometer manufactured by TA Instruments as follows. Approximately 1.3 g of a toner sample was placed in a jig for 25 mm diameter, and pressed with a press heated to 50°C under a load of 30 kg for 10 minutes to form a pellet. The obtained pellet was placed in a measurement device equipped with circular parallel plates with a diameter of 25 mm, and the temperature was raised to 120°C, and the upper plate was lowered to adjust the thickness of the pellet to 3.0 to 3.5 mm. Thereafter, the temperature was lowered, and the measurement was performed under the following conditions: measurement frequency 6.28 rad / s, initial temperature 40°C, pre-measurement delay time 3 minutes, automatic tension adjustment (pulling direction, initial force 0, automatic tension sensitivity 2.0 g, automatic tension switching elastic modulus 1.0 x 10 ８ 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.

[0176] <Remaining Rate on Sieve> The remaining rate on sieve was measured by the following method. 20 g of toner was placed in a plastic container, placed in a thermo-hygrostat at a temperature of 50°C and a relative humidity of 40%, and held for 20 hours. After removing the container from the thermo-hygrostat, the toner was taken out and sieved through a 60-mesh sieve. The weight of the toner remaining on the sieve was measured, and the remaining rate (mass %), which is the ratio of this weight to the total weight of the toner, was calculated. The calculation result was shown as the "remaining rate on sieve."

[0177] 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.

[0178] <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% DBS aqueous solution), and 68.7 parts of demineralized water were placed in a CSTR-type stirring vessel equipped with a 45-degree inclined three-stage paddle blade, heated to 90°C in the stirring vessel, and mixed for 20 minutes. Next, while the dispersion was still heated to 90°C, a circulating emulsification was performed under a pressure of 25 MPa using a valve homogenizer (Gaulin, 15-M-8PA type), and the particle size was measured with a Nanotrac and dispersed until the median diameter (D50) reached 245 nm, producing wax dispersion W1 (emulsion solids concentration: 30.5%).

[0179] <Pigment Dispersion G1> 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 were added to a propeller-equipped agitator container and pre-dispersed to obtain a pigment premix. This premix was fed as a raw material slurry to a wet bead mill 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 fed from the feed port at a feed 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. Note that operation was carried out while circulating cooling water at approximately 10°C from the jacket. The median diameter (D50) of the dispersed pigment was 157 nm, and the pigment solids concentration was 24.6%.

[0180] <Amorphous Polyester Resin> Amorphous polyester resins A, B, C, D, and E were produced as follows. The polycarboxylic acid component, polyhydric alcohol component, and polymerization catalyst, with the charge compositions shown in Table 2, were charged into a reaction vessel equipped with a distillation column. The amount of polymerization catalyst is the amount (ppm) relative to the acid component. Next, the rotation speed of the stirring blade in the reaction vessel was maintained at 120 rpm, and the temperature was raised. The reaction system was heated to a temperature of 265°C, and this temperature was maintained to carry out the esterification reaction. 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 of 133 Pa. The 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 vacuum was increased as the viscosity increased. The condensation reaction was carried out until the torque of the stirring blade reached a value indicating the desired softening temperature. The stirring was stopped when a predetermined torque was reached, the reaction system was returned to normal pressure, and the reaction product was removed (discharged) from the reaction vessel by pressurizing with nitrogen to obtain each amorphous polyester resin. The physical properties (glass transition temperature, softening temperature, mass average molecular weight, acid value) of the obtained amorphous polyester resins A, B, C, D, and E were measured. The results are shown in Table 2.

[0181]

[0182] <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 and stirred uniformly with a stirrer to prepare a resin solution. Next, 100 parts of demineralized water was added to a round-bottom flask, and the prepared resin solution was added. The mixture was then dispersed at 8,000 rpm for 10 minutes using a homogenizer (IKA T25 model). The solvent was then 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 found to be 180 nm.

[0183] <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 and stirred uniformly with a stirrer to prepare a resin solution. Next, 100 parts of demineralized water was added to a round-bottom flask, and the prepared resin solution was added. The mixture was then dispersed at 8,000 rpm for 10 minutes using a homogenizer (IKA T25). The solvent was then 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 found to be 190 nm.

[0184] <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 and stirred uniformly with a stirrer to prepare a resin solution. Next, 100 parts of demineralized water was added to a round-bottom flask, and the prepared resin solution was added. The mixture was then dispersed at 8,000 rpm for 10 minutes using a homogenizer (IKA T25 model). The solvent was then 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 found to be 200 nm.

[0185] <Amorphous Polyester Dispersion P4> 25 parts of amorphous polyester resin D was dissolved in 75 parts of methyl ethyl ketone (MEK), and 0.393 g of dimethylaminoethanol was added and stirred uniformly with a stirrer to prepare a resin solution. Next, 100 parts of demineralized water was added to a round-bottom flask, and the prepared resin solution was added. The mixture was then dispersed at 8,000 rpm for 10 minutes using a homogenizer (IKA T25 model). The solvent was then removed by vacuum distillation at 80 ° C using an aspirator to obtain Amorphous Polyester Dispersion P4. The median diameter (D50) of the amorphous polyester resin particles in Amorphous Polyester Dispersion P4 was measured using a Nanotrac and found to be 202 nm.

[0186] <Amorphous Polyester Dispersion P5> 25 parts of amorphous polyester resin E was dissolved in 75 parts of methyl ethyl ketone (MEK), and 0.795 g of dimethylaminoethanol was added and stirred uniformly with a stirrer to prepare a resin solution. Next, 100 parts of demineralized water was added to a round-bottom flask, and the prepared resin solution was added. The mixture was then dispersed at 8,000 rpm for 10 minutes using a homogenizer (IKA T25 model). The solvent was then removed by vacuum distillation at 80 °C using an aspirator to obtain Amorphous Polyester Dispersion P5. The median diameter (D50) of the amorphous polyester resin particles in Amorphous Polyester Dispersion P5 was measured using a Nanotrac and found to be 201 nm.

[0187] <Crystalline Polyester Resin Dispersion C1> 54 parts of crystalline polyester resin A (sebacic acid-ethylene glycol copolymer, melting point 72°C, acid value 65.4 mgKOH / g) were 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 a rotation speed of 5,200 rpm, and then dispersed in one pass at 20,000 psi using a high-pressure homogenizer (Powrex Corporation, Microfluidizer). 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.

[0188] <Crystalline Polyester Resin Dispersion C2> 72 parts of crystalline polyester resin B (adipic acid-terephthalic acid-1,6-hexanediol copolymer, melting point 80°C, acid value 1.0 mgKOH / g or less) were 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 a rotation speed of 5,200 rpm, and then dispersed in one pass at 20,000 psi using a high-pressure homogenizer (Powrex Corporation, Microfluidizer). The solvent was then removed by vacuum distillation at 80°C using an aspirator, yielding 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.

[0189] <Crystalline Polyester Resin Dispersion C3> 54 parts of crystalline polyester resin A (sebacic acid-ethylene glycol-propylene glycol copolymer, melting point 60.2°C, acid value 6.4 mgKOH / g) 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 a rotation speed of 5,200 rpm, and then dispersed in one pass at 20,000 psi using a high-pressure homogenizer (Powrex Corporation, Microfluidizer). 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 found to be 185 nm.

[0190] Example 1 Toner T1 was prepared as follows.

[0191] A mixer equipped with a stirring device, a heating / cooling device, and each raw material / auxiliary agent charging device, amorphous polyester dispersion P2 in an amount so that the solids content is 75 parts, a 20% DBS aqueous solution in an amount so that the solids content is 0.05 parts, a wax dispersion W1 in an amount so that the solids content is 7 parts, a crystalline polyester dispersion C1 in an amount so that the solids content is 3 parts, 135 parts of demineralized water, a 10% magnesium sulfate heptahydrate aqueous solution in an amount so that the solids content is 3.047 parts, a 1% aluminum sulfate aqueous solution in an amount so that the solids content is 0.082 parts, and a pigment dispersion G1 in an amount so that the solids content is 5 parts were added in sequence while stirring. The internal temperature was raised to 34.0 ° C. over 40 minutes, and then raised to 38.0 ° C. over 90 minutes. Here, the volume median particle size (Dv50) was measured using a Multisizer and was found to be 5.46 μm. Next, a mixture of amorphous polyester dispersion P2 for the shell in an amount to give a solids content of 10 parts and 0.2 parts of a 20% DBS aqueous solution (solids content (amount to give a solids content of 2 parts per 100 parts of polyester)) was added dropwise over 30 minutes. 30 minutes after the end of the dropwise addition, 232 parts of demineralized water and an amount of 10% EDTA aqueous solution to give a solids content of 5.0 parts were added. The pH of the system was adjusted to 8.4 using a 4.8% potassium hydroxide aqueous solution, and the temperature was raised to 63°C over 90 minutes, and then to 67°C over 60 minutes. The mixture was then cooled to 30°C over 30 minutes.

[0192] The resulting dispersion was extracted and filtered under suction with an aspirator using No. 5C filter paper manufactured by Toyo Roshi Kaisha, Ltd. 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, followed by stirring for 30 minutes. This process was repeated until the electrical conductivity of the filtrate reached 2 μS / cm, and the resulting cake was then dried for 48 hours in a blower dryer set at 30° C. to obtain toner base particles B1.

[0193] To the thus prepared toner base particles B1 (100 parts), 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 5,000 rpm for 1 minute, followed by sieving to obtain toner T1. The core / shell structure of this toner T1 is as shown in Table 3. Note that the toner T1 obtained in Example 1 does not contain bisphenol A derivatives or trimellitic anhydride components, nor does it contain antimony or tin in its manufacturing process, and therefore does not substantially contain these components. The same applies to toners T2 to T6 in Examples 2 to 6 below.

[0194] [Example 2] Toner T2 was produced in the same manner as Toner T1, except that Amorphous Polyester Dispersion P2 was used in an amount to give a solids content of 73 parts, Crystalline Polyester Dispersion C1 was used in an amount to give a solids content of 5 parts, and Amorphous Polyester Dispersion P2 for the shell was changed to Amorphous Polyester Dispersion P3 in Example 1. The core / shell structure of Toner T2 is as shown in Table 3.

[0195] [Example 3] Toner T3 was produced in the same manner as Toner T1, except that in Example 1, crystalline polyester dispersion C1 was used in an amount to give a solids content of 10 parts, wax dispersion W1 was used in an amount of 0.0 part (no addition), and amorphous polyester dispersion P2 for the shell was changed to amorphous polyester dispersion P1. The core / shell structure of Toner T3 is as shown in Table 3.

[0196] [Example 4] Toner T4 was produced in the same manner as Toner T1, except that Amorphous Polyester Dispersion P2 was used in an amount to give a solids content of 68 parts, Crystalline Polyester Dispersion C1 was used in an amount to give a solids content of 10 parts, and Amorphous Polyester Dispersion P2 for the shell was changed to Amorphous Polyester Dispersion P3 in Example 1. The core / shell structure of Toner T4 is shown in Table 3.

[0197] [Example 5] Toner T5 was produced in the same manner as Toner T1, except that in Example 1, Amorphous Polyester Dispersion P2 was used in an amount such that the solids content was 68 parts, Crystalline Polyester Dispersion C1 was used in an amount such that the solids content of Crystalline Polyester Dispersion C2 was 10 parts, and Amorphous Polyester Dispersion P2 for the shell was changed to Amorphous Polyester Dispersion P3. The core / shell structure of Toner T5 is as shown in Table 3.

[0198] [Example 6] Toner T6 was produced in the same manner as Toner T1, except that in Example 1, Amorphous Polyester Dispersion P2 was used in an amount such that the solids content of Amorphous Polyester Dispersion P1 was 68 parts, Crystalline Polyester Dispersion C1 was used in an amount such that the solids content was 10 parts, and Amorphous Polyester Dispersion P2 for the shell was replaced with Amorphous Polyester Dispersion P1. The core / shell structure of Toner T6 is as shown in Table 3.

[0199] Comparative Example 1 Toner T7 was produced in the same manner as Toner T1, except that Amorphous Polyester Dispersion P2 was added in an amount such that the solids content of Amorphous Polyester Dispersion P1 was 78 parts, Crystalline Polyester Dispersion C1 was added at 0.0 parts (no addition), and Amorphous Polyester Dispersion P2 for the shell was replaced with Amorphous Polyester Dispersion P1 in Example 1. The core / shell structure of Toner T7 is as shown in Table 3.

[0200] Comparative Example 2 Toner T8 was produced in the same manner as Toner T1, except that Amorphous Polyester Dispersion P2 was used in an amount to give a solids content of 78 parts, Crystalline Polyester Dispersion C1 was used in an amount of 0.0 parts (no addition), and Amorphous Polyester Dispersion P2 for the shell was replaced with Amorphous Polyester Dispersion P1 in Example 1. The core / shell structure of Toner T8 is shown in Table 3.

[0201] Comparative Example 3 Toner T9 was produced in the same manner as Toner T1, except that crystalline polyester dispersion C1 was replaced with crystalline polyester dispersion C2 and amorphous polyester dispersion P2 for the shell was replaced with amorphous polyester dispersion P1 in Example 1. The core / shell structure of this toner T9 is as shown in Table 3.

[0202] Comparative Example 4 Toner T10 was produced in the same manner as Toner T1, except that Amorphous Polyester Dispersion P2 was used in an amount such that the solids content was 73 parts, Crystalline Polyester Dispersion C1 was used in an amount such that the solids content of Crystalline Polyester Dispersion C3 was 5.0 parts, and Amorphous Polyester Dispersion P2 for the shell was changed to Amorphous Polyester Dispersion P3 in Example 1. The core / shell structure of Toner T10 is as shown in Table 3.

[0203] Comparative Example 5 Toner T11 was produced in the same manner as Toner T1, except that Amorphous Polyester Dispersion P2 was added in an amount such that the solids content of Amorphous Polyester Dispersion P5 was 78 parts, Crystalline Polyester Dispersion C1 was added at 0.0 parts (no addition), and Amorphous Polyester Dispersion P2 for the shell was replaced with Amorphous Polyester Dispersion P1 in Example 1. The core / shell structure of Toner T11 is as shown in Table 3.

[0204] Comparative Example 6 Toner T12 was produced in the same manner as Toner T1, except that Amorphous Polyester Dispersion P2 was added in an amount such that the solids content of Amorphous Polyester Dispersion P4 was 78 parts, Crystalline Polyester Dispersion C1 was added at 0.0 parts (no addition), and Amorphous Polyester Dispersion P2 for the shell was replaced with Amorphous Polyester Dispersion P1 in Example 1. The core / shell structure of Toner T12 is as shown in Table 3.

[0205] Comparative Example 7 Toner T13 was produced in the same manner as Toner T1, except that the amounts of Amorphous Polyester Dispersion P2 and Wax Dispersion W1 were changed to 85 parts solids, 0.0 parts (no addition), Crystalline Polyester Dispersion C1 to 10.0 parts solids, and Amorphous Polyester Dispersion P2 for the shell were changed to 0.0 parts (no addition) in Example 1. The core / shell structure of Toner T13 is shown in Table 3.

[0206] The toners T1 to T13 thus obtained were quantitatively analyzed for bisphenol A, bisphenol A (EO adduct), bisphenol A (PO adduct), trimellitic acid, tin, and antimony. The quantitative analysis method was as described above. The results showed that the total content of bisphenol A, bisphenol A (EO adduct), and bisphenol A (PO adduct) was 50 ppm or less. The total content of trimellitic anhydride and trimellitic acid was 10 ppm or less. The tin content was less than 10 ppm, and the antimony content was 1 ppm or less.

[0207] The volume median particle diameter (Dv50) and average circularity of the obtained toners T1 to T13 were measured, and the results are shown in Table 4. In addition, the complex viscosity and sieving residual ratio of the obtained toners T1 to T13 were measured, and the results are shown in Table 5.

[0208]

[0209]

[0210] [Printing Evaluation] <Low-Temperature Fixability Evaluation> The obtained toner was printed on a PET film (Diafoil T-600E, manufactured by Mitsubishi Chemical Corporation) at a printing speed of 16 ppm with a toner adhesion amount of about 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. ２An unfixed toner image of 100 mm was printed on the PET film of the evaluation sample. 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 was not coated with silicone oil. The roller surface temperature was set to 130°C, and the image was fixed 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 toner remaining on the PET film of the evaluation sample was measured, assuming the area with the Cellotape (registered trademark) adhered to it as 100%. The low-temperature fixability was evaluated from this area percentage using the following evaluation criteria. The evaluation results are shown in Table 5. (Evaluation Criteria) ◯: Toner remained on 70% or more of the PET film. Δ: Toner remained on 40% or more but less than 70% of the PET film. ×: Toner remained on less than 40% of the PET film. Alternatively, the fixed image was offset.

[0211] <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.) in an amount of adhesion of approximately 0.8 mg / cm using two toner cartridges, 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. ２ The heat roll fixing machine had a roller diameter of 27 mm, a nip width of 9 mm, a fixing speed of 95 mm / sec, a heater on the upper roller, and a roller surface made of PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) without silicone oil coating. The roller surface temperature was set to 150°C, and the adhesion amount was about 0.8 mg / cm. ２A recording sheet bearing an unfixed toner image was transported to the fixing nip section, and a fixed image was obtained. An abrasion test was performed by abrading 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 distance traveled was 2 cm, and a total of three back-and-forth abrasion tests were performed. The travel speed was approximately 1 cm / s, and the angle between the direction of travel and the tip of the flathead screwdriver was 90°. The degree of abrasion was visually observed and evaluated according to the following criteria. The evaluation results are shown in Table 5. (Evaluation Criteria) ○: No abrasion was observed, or one or less small white dots were left due to abrasion. △: The abrasion line was less than 3 mm long, or multiple small white dots were present. ×: The abrasion line was 3 mm or longer.

[0212]

[0213] <Discussion> From the above examples and comparative examples, it was found that the present toner is a toner that uses materials with low environmental impact, has excellent low-temperature fixing properties, and also has excellent printed image strength, by having an appropriate complex viscosity range and sieving retention rate.

[0214] Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications are possible within the scope of the effects of the invention. This application is based on Japanese Patent Application No. 2024-054130 filed on March 28, 2024, and is incorporated by reference in its entirety.

Claims

1. A toner comprising at least base particles and external additives, wherein the base particles contain an amorphous polyester resin and a crystalline polyester resin, and wherein, when measured at a measurement frequency of 6.28 rad / sec and a temperature rise rate of 4°C / min, the complex viscosity at 80°C is 100,000 Pa·s or less and the complex viscosity at 110°C is 2,000 Pa·s or less, and when 20 g of the toner is placed in a thermo-hygrostat kept at a temperature of 50°C and a relative humidity of 40%, and held for 20 hours, and then sieved through a 60-mesh sieve, the residual rate on the sieve is less than 5%.

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

3. The toner according to claim 1 or 2, wherein the total content of bisphenol A and other compounds having a bisphenol structure in the toner is less than 100 ppm.

4. The toner according to claim 1 or 2, wherein the total content of trimellitic anhydride and trimellitic acid in the toner is less than 1000 ppm.

5. The toner according to claim 1 or 2, wherein the total content of antimony and tin in said toner is less than 1000 ppm.

6. The toner according to claim 1 or 2, wherein the melting point of said crystalline polyester resin is 62°C or higher and 90°C or lower.

7. The toner according to claim 1 or 2, wherein the glass transition temperature of the amorphous polyester resin is 45°C or higher and 65°C or lower.

8. The toner according to claim 1 or 2, wherein the acid value of the amorphous polyester resin is 4 mgKOH / g or more and 20 mgKOH / g or less.

9. The toner according to claim 1 or 2, wherein the complex viscosity at 80° C. is 30,000 Pa·s or less.

10. The toner according to claim 1 or 2, wherein the complex viscosity at 110° C. is 1,000 Pa·s or less.

11. The toner according to claim 1 or 2, wherein the crystalline polyester resin is a polyester resin other than polyethylene terephthalate.

12. The toner according to claim 1 or 2, which does not exhibit a crystal melting peak in a temperature range of 200° C. or higher in differential scanning calorimetry (DSC).

13. The toner according to claim 1 or 2, wherein the amorphous polyester resin has a structure derived from two or more kinds of aliphatic polyhydric alcohols as a polyester-forming structure.

14. The toner according to claim 13, wherein the aliphatic polyhydric alcohol comprises a branched-chain aliphatic polyhydric alcohol.

15. The toner according to claim 13, wherein the aliphatic polyhydric alcohol comprises a dihydric alcohol and a trihydric or higher alcohol.

16. The toner according to claim 1 or 2, wherein the base particles further contain a colorant.

17. The toner according to claim 1 or 2, wherein the volume median particle diameter (Dv50) is 3.0 μm or more and 7.0 μm or less.

18. The toner according to claim 1 or 2, wherein the average circularity is 0.92 or more and 0.99 or less.

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

20. An image forming device containing the toner according to claim 1 or 2.

21. A method for producing a toner comprising at least a step of producing primary polymer particles, a aggregation step, a ripening step, and an external addition step, wherein the toner comprises at least base particles and an external additive, the base particles containing an amorphous polyester resin, a crystalline polyester resin, and a colorant, 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, and when 20 g of the toner is placed in a thermo-hygrostat kept at a temperature of 50°C and a relative humidity of 40%, and held for 20 hours and then sieved, the residual rate on the sieve is less than 5%, and the primary polymer particles are obtained by emulsion polymerization.

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