Crystalline-polyester-containing toner

Abstract

Provided is a toner having excellent low-temperature adherence and excellent heat-resistant storage stability. The toner according to one embodiment includes a resin, a wax, and a pigment. The resin contains a crystalline polyester and an amorphous resin, and the crystalline polyester contains, as constituent materials, a C10-12 dicarboxylic acid component and a C2-8 diol component.

Description

Crystalline polyester-containing toner

[0001] The present invention relates to a crystalline polyester-containing toner.

[0002] Electrophotography is widely used as one of the image forming methods in copiers, printers, facsimiles, etc. Typical image formation using electrophotography involves irradiating a photoconductive insulator (photoreceptor) uniformly charged using a contact-type charging roller or a corona charger that utilizes corona discharge with laser light, LED light, or the like to form an electrostatic latent image, and then electrostatically attaching electrostatic image developing toner (hereinafter, simply referred to as toner) to the electrostatic latent image to form a toner image; a transfer process in which the toner image is transferred to a recording medium, such as a recording medium; and a fixing process in which the transferred toner image is melted on the recording medium by contact with a heat medium or by infrared radiation, and then fixed by heat dissipation. In recent years, technologies enabling low-temperature fixing have been developed to reduce energy consumption in the fixing process. However, such toners with excellent low-temperature fixing properties are prone to a blocking phenomenon, in which the toner particles solidify due to heat generated by the machine in use or during storage, resulting in poor heat-resistant storage stability. To address this issue, for example, a toner disclosed in Japanese Patent Application Laid-Open No. 2003-149999 has been proposed as a toner that can achieve both low-temperature fixability and heat-resistant storage stability.

[0003] Japanese Patent Application Laid-Open No. 2006-084743

[0004] Patent Document 1 discloses that when T1 is the glass transition temperature before thermal melting when heated from −20° C. to 150° C. at a temperature increase rate of 10° C. / min, and T2 is the glass transition temperature after thermal melting when heated from −20° C. to 150° C. at a temperature increase rate of 10° C. / min, cooled to −20° C. at a temperature decrease rate of 10° C. / min, and further heated at a temperature increase rate of 10° C. / min, a toner that satisfies 10° C.<(T1−T2)<60° C., a toner that satisfies 0<Q2 / Q1<2 / 3 when the endothermic heat of the melting point peak before thermal melting is Q1 and the endothermic heat of the melting point peak after thermal melting is Q2, and a toner that satisfies 10° C.<(T1−T2)<60° C. and 0<Q2 / Q1<2 / 3 can achieve both low temperature fixability and heat-resistant storage stability. However, since the toner of Patent Document 1 contains a resin with a low softening point and excellent low-temperature fixability, there is a risk that the toner may lack heat-resistant storage stability, although it has excellent low-temperature fixability.

[0005] Therefore, an object of the present invention is to provide a toner that has excellent low-temperature fixability and heat-resistant storage stability.

[0006] In order to solve the above problems, the toner of the present disclosure is characterized by containing a plurality of specific resins. That is, the disclosed technology is as follows. One aspect of the disclosed technology is a toner containing a resin, a wax, and a pigment, wherein the resin contains a crystalline polyester and an amorphous resin, and the crystalline polyester is made from a dicarboxylic acid component having 10 to 12 carbon atoms and a diol component having 2 to 8 carbon atoms as constituent raw materials. The content of the crystalline polyester is preferably 0.5 to 10.0 mass% based on the mass of the resin. The content of the crystalline polyester is preferably 2.0 to 4.0 mass% based on the mass of the resin. The toner further contains domains composed of the crystalline polyester and the wax, and the average diameter of the domains is preferably 75 nm or less. The molecular weight distribution curve of the toner measured by gel permeation chromatography (GPC) shows that the molecular weight (M) is 1 x 10 ５ ~1 x 10 ７ and the molecular weight distribution curve includes a peak Sp having a peak top at a molecular weight (M) of 1×10 ５When the value on the vertical axis in the graph is Pb, it is preferable that the ratio (Pt / Pb) of the height (maximum value) Pt of the peak top of peak Sp on the vertical axis to Pb is 1.3 or more. The horizontal axis of the molecular weight distribution curve represents the molecular weight, and the vertical axis of the molecular weight distribution curve represents the area %. The area % is the area % of each peak based on the total area of ​​all peaks in the spectrum obtained as the detection intensity by a differential refractive index detector, with the horizontal axis representing the retention time in GPC measurement of the toner. The GPC measurement conditions are as follows: Column temperature: 40°C Eluent composition: tetrahydrofuran Eluent flow rate: 1.0 mL / min Calibration standard reagent: standard polystyrene Detector: differential refractive index detector Detector temperature: room temperature

[0007] According to the present invention, by using a toner containing a plurality of specific resins, it is possible to provide a toner having excellent low-temperature fixability and heat-resistant storage stability.

[0008] FIG. 2 is an explanatory diagram illustrating a molecular weight distribution curve of a toner.

[0009] In the present disclosure, when a compound name is simply indicated, it is intended to include all isomers thereof.

[0010] In the present disclosure, when "(meth)acrylic", "(meth)acrylic acid", etc. are mentioned, it means "acrylic and / or methacrylic", "acrylic acid and / or methacrylic acid", etc.

[0011] The toner of the present disclosure preferably contains a resin, a wax, and a pigment. The resin preferably contains a crystalline polyester and an amorphous resin, and the crystalline polyester preferably contains a dicarboxylic acid component having 10 to 12 carbon atoms and a diol component having 2 to 8 carbon atoms as constituent raw materials.

[0012] The structure of the toner particles constituting the toner is not particularly limited, and examples thereof include toner particles having a core-shell structure in which a particulate core is made of a uniform toner component and the surface of the core is partially or entirely covered with a resin layer different from the toner component.

[0013] The average particle size of the toner particles is not particularly limited as long as it does not impair the effects of this embodiment, but is preferably 3 to 18 μm, more preferably 3 to 12 μm, and even more preferably 3 to 10 μm. When the average particle size of the toner particles is within this range, it is possible to obtain effects such as relatively easy production, reducing the amount of toner particles used during printing, and obtaining clear prints. Note that the average particle size of the toner particles is the volume average particle size, which can be measured using a commercially available device, such as a Coulter counter, and the volume average particle size means the diameter at 50% of the volume.

[0014] When the toner particles have a core-shell structure, the thickness of the resin layer serving as the shell is not particularly limited, and for example, the lower limit of the thickness of the resin layer may be 10 nm or more, 15 nm or more, 20 nm or more, 30 nm or more, 40 nm or more, 50 nm or more, or 100 nm or more, and the upper limit of the thickness of the resin layer may be 500 nm or less, 450 nm or less, 400 nm or less, 300 nm or less, or 200 nm or less.

[0015] When the toner particles have a core-shell structure, the material of the resin layer serving as the shell may be, for example, an amino resin, a urea-formaldehyde resin, a melamine resin, a benzoguanamine resin, a urea resin, a polyamide resin, an epoxy resin, a polyvinyl and polyvinylidene resin, an acrylic resin, a polymethyl methacrylate resin, a polyacrylonitrile resin, a polyvinyl acetate resin, a polyvinyl alcohol resin, a polyvinyl butyral resin, a polystyrene resin such as a styrene-acrylic copolymer resin, a halogenated resin such as polyvinyl chloride, or the like. Examples of resins that can be used include olefin resins, polyester resins such as polyethylene terephthalate resins and polybutylene terephthalate resins, polycarbonate resins, polyethylene resins, polyvinyl fluoride resins, polyvinylidene fluoride resins, polytrifluoroethylene resins, polyhexafluoropropylene resins, copolymers of vinylidene fluoride and an acrylic monomer, copolymers of vinylidene fluoride and vinyl fluoride, fluoro terpolymers such as terpolymers of tetrafluoroethylene, vinylidene fluoride and a non-fluorinated monomer, and silicone resins.

[0016] The molecular weight distribution curve (see FIG. 1) of the toner (including all of the toner components) measured by gel permeation chromatography (GPC) shows that the molecular weight (M) is 1×10 ５ ~1 x 10 ７ and the molecular weight distribution curve includes a peak Sp having a peak top in the range of 1×10 ５ When the value on the vertical axis in (a) is Pb, the ratio (Pt / Pb) of the vertical height (maximum value) Pt of the peak top of peak Sp to Pb is preferably 1.3 or more, more preferably 1.3 to 4.0, and even more preferably 1.3 to 3.0. When Pt / Pb is within this range, the fixability and heat-resistant storage stability of the toner are improved, and further, the moldability is improved. The horizontal axis of the molecular weight distribution curve is the molecular weight (M), and the vertical axis of the molecular weight distribution curve is the area %. Here, the area % is the area % of each peak based on the total area of ​​all peaks in the spectrum (GPC measurement result) obtained in GPC measurement of the toner, with the horizontal axis being the retention time and the vertical axis being the detection intensity by a differential refractive index detector. The GPC measurement conditions are as follows: Column temperature: 40°C Eluent composition: tetrahydrofuran Eluent flow rate: 1.0 mL / min Calibration standard reagent: standard polystyrene Detector: differential refractive index detector Temperature: room temperature

[0017] A more specific example of GPC measurement is as follows: 20.0 mg of toner is dissolved in 10.0 ml of tetrahydrofuran (THF), and the solution is centrifuged (4°C, 2000 rpm x 10 min) using a centrifuge, and the supernatant is removed. If the toner is difficult to dissolve in THF, the THF can be heated to promote dissolution of the toner. The heating temperature is not particularly limited, and can be, for example, 60°C. The resulting supernatant is subjected to GPC measurement under the above conditions, and a spectrum (GPC measurement result of the toner) is obtained, with the horizontal axis representing retention time and the vertical axis representing the detection intensity using a differential refractive index detector. Next, separate from the GPC measurement of the toner, GPC measurement is performed on several types of standard polystyrene with different molecular weights, and a graph of molecular weight (M) versus retention time is prepared. Using this prepared calibration curve, the horizontal axis of the spectrum (GPC measurement result of the toner) is converted from retention time to molecular weight (log M). Furthermore, the intensity detected by the differential refractive index detector, which is the vertical axis of the spectrum (results of GPC measurement of the toner), is converted into the area % of each peak based on the total area of ​​all peaks in the obtained spectrum (results of GPC measurement), to create a molecular weight distribution curve. Here, the molecular weight of the standard polystyrene used to create the calibration curve is not particularly limited, but for example, a combination of polystyrene having a molecular weight of 5,480,000, polystyrene having a molecular weight of 427,000, polystyrene having a molecular weight of 96,400, polystyrene having a molecular weight of 16,200, and polystyrene having a molecular weight of 2,630 can be used.

[0018] The GPC device used for the GPC measurement is not particularly limited, but for example, an EXTREMA GPLC system (manufactured by JASCO Corporation) can be used. The column used for the GPC measurement is not particularly limited, but two connected Shodex 806L columns (manufactured by Showa Denko K.K.) can be used.

[0019] The toner of the present disclosure preferably further contains domains made of crystalline polyester and wax, where the domains refer to a state in which a sea-island structure is formed in which the crystalline polyester and wax form islands in a sea of ​​amorphous polyester.

[0020] The average diameter of the domains in the toner is preferably 50 nm or more, 53 nm or more, 55 nm or more, and is preferably 80 nm or less, 78 nm or less, 75 nm or less, etc. The average area of ​​the domains in the toner is 1,700,000 nm ２ Above, 1,800,000nm ２ Above, 1,900,000nm ２ More than 5,000,000 nm is preferred. ２ Below, 2,300,000nm ２ Below, 2,200,000nm ２ The average area of ​​the domains multiplied by the average number of domains per unit area is preferably 4,200 (nm ２ / μm ２ ) or less.

[0021] By setting the average diameter and average area of ​​the domains in the toner, and the average value of the product of the average area of ​​the domains and the number of domains per unit area, within the above numerical ranges, the exposure of the low-melting-point materials, crystalline polyester and wax, to the surface is suppressed, making it difficult for the glass transition point to decrease, and resulting in a toner with excellent heat-resistant storage stability.

[0022] The method for measuring the average diameter, average area, and average number of domains per unit area in a toner will be described. First, a slice sample is prepared by embedding the toner in a room-temperature curing resin. Scanning transmission electron microscope (STEM) analysis is performed on the slice sample. The obtained SEM image is binarized into crystalline and non-crystalline portions using image analysis software. From the crystalline portion of the binarized image, the average diameter, average area, and average number of domains per unit area are calculated.

[0023] 1-1. Resin 1-1-1. Crystalline Polyester The toner preferably contains a crystalline polyester. The crystalline polyester preferably has a crystallinity of 10% or more, and exhibits a clearly observable endothermic peak due to the melting of the crystalline component in differential scanning calorimetry (DSC).

[0024] The crystalline polyester preferably contains, as constituent raw materials, a dicarboxylic acid component having 10 to 12 carbon atoms and a diol component having 2 to 8 carbon atoms. That is, the crystalline polyester is preferably one obtained by reacting a dicarboxylic acid component having 10 to 12 carbon atoms with a diol component having 2 to 8 carbon atoms.

[0025] The dicarboxylic acid component having 10 to 12 carbon atoms is not particularly limited, and examples thereof include aliphatic dicarboxylic acids, aromatic dicarboxylic acids, alicyclic carboxylic acids, and derivatives thereof. These dicarboxylic acids may be either saturated or unsaturated dicarboxylic acids. These may be used alone or in combination in any ratio.

[0026] Of these dicarboxylic acids, aliphatic dicarboxylic acids are preferred, 1,8-octanedicarboxylic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, structural isomers of these dicarboxylic acids, and derivatives of these dicarboxylic acids are more preferred, 1,8-octanedicarboxylic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, and derivatives of these dicarboxylic acids are even more preferred, and 1,8-octanedicarboxylic acid, 1,9-nonanedicarboxylic acid, and 1,10-decanedicarboxylic acid are particularly preferred.

[0027] The diol component having 2 to 8 carbon atoms is not particularly limited, and examples thereof include aliphatic diols, aromatic diols, alicyclic diols, aliphatic ether diols, 1,4-bis(hydroxymethyl)cyclohexane; etherified bisphenols such as bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A, and polyoxypropylenated bisphenol A; and other dihydric alcohol monomers and derivatives thereof. These diols may be either saturated or unsaturated diols. These may be used alone or in combination in any ratio.

[0028] Of these diols, aliphatic diols and aliphatic ether diols are preferred, and 1,2-ethanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-septanediol, 1,8-octanediol, neopentyl glycol, structural isomers of these diols, and derivatives of these diols are more preferred, and 1,2-ethanediol, 1,3-propanediol, 1,4- Butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-septanediol, 1,8-octanediol, neopentyl glycol, and derivatives of these diols are more preferred, and 1,2-ethanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-septanediol, 1,8-octanediol, and neopentyl glycol are particularly preferred.

[0029] The weight average molecular weight (Mw) of the crystalline polyester is preferably 10,000 to 30,000, and more preferably 10,000 to 21,000. The weight average molecular weight (Mw) of the crystalline polyester can be determined by the GPC measurement described above. When the weight average molecular weight (Mw) of the crystalline polyester is within this range, the toner has good fixability and heat-resistant storage stability, and further has good moldability.

[0030] The weight average molecular weight (Mw) of the crystalline polyester can be measured in the same manner as in the GPC measurement of the toner, except that centrifugation is performed.

[0031] The melting point of the crystalline polyester is preferably 50° C. or higher and lower than 100° C., more preferably 60° C. or higher and lower than 90° C., and even more preferably 70° C. or higher and lower than 85° C. When the melting point of the crystalline polyester is within this range, the toner has good fixability and heat-resistant storage stability, and further has good moldability.

[0032] The melting point of the crystalline polyester is determined using a DSC curve and is defined as follows. The DSC curve is obtained during temperature rise when DSC measurement is performed in accordance with ASTM D3418-82 or JIS K7121-1987. Specifically, the measurement method is as follows: first, about 10 mg of a sample is placed in an aluminum cell, and the cell is placed in a differential scanning calorimeter (manufactured by Seiko Instruments Inc., product name: SCC-6200), and 50 ml of N is added per minute. ２ Measurements are performed while blowing in gas. The sample is then heated from 20°C to 110°C at a rate of 10°C per minute and held at 110°C for 10 minutes to remove thermal history below the glass transition temperature (Tg) of the crystalline polyester. Next, the sample is cooled from 110°C to 20°C at a rate of 10°C per minute and held at 20°C for 10 minutes. Next, the sample is heated a second time from 20°C to 250°C at a rate of 10°C per minute, and the apex temperature of the endothermic peak associated with the melting of the crystalline component in the DSC heating curve observed at this time is taken as the melting point.

[0033] The glass transition temperature (Tg) of the crystalline polyester is not particularly limited, but is preferably 40 to 100° C., more preferably 50 to 90° C., and even more preferably 60 to 80° C. When the glass transition temperature (Tg) of the crystalline polyester is within this range, the toner has good anti-fusing properties, and the toner has good fixing strength and moldability.

[0034] The Tg of the crystalline polyester can be measured by the following method: About 10 mg of a sample is placed in an aluminum cell, and the cell is placed in a differential scanning calorimeter (manufactured by Seiko Instruments Inc., trade name: SCC-6200), and 50 ml of N ２Measurements are performed in accordance with JIS K 7121-1987 while blowing in gas. First, the sample is heated between -20 and 110°C at a rate of 10°C per minute, and then held at 110°C for 10 minutes (leaving the sample at or below the glass transition temperature (Tg) of the sample) to remove thermal history. Next, the sample is cooled from 110°C to -20°C at a rate of 10°C per minute, and then held at -20°C for 10 minutes. Next, the sample is heated from -20°C to 110°C at a rate of 10°C per minute for a second heating. The midpoint glass transition temperature (Tmg) described in 9.3 of JIS K 7121-1987 is determined from the DSC heating curve observed at this time, and this temperature is designated as Tg in this embodiment.

[0035] The degree of crystallinity of the crystalline polyester is not particularly limited as long as it is 10% or more, but from the viewpoints of improving fixing properties and moldability, it is preferably 20 to 70%, more preferably 30 to 80%. The degree of crystallinity can be increased by adjusting molding conditions or using a crystal nucleating agent. The degree of crystallinity can also be determined by X-ray diffraction.

[0036] 1-1-2. Amorphous Resin The amorphous resin can be a known toner resin, and is not particularly limited, and examples thereof include polyester; styrene-(meth)acrylic acid copolymer resin; styrene-based resins such as polystyrene, poly-α-methylstyrene, polychlorostyrene, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, and styrene-acrylonitrile-acrylic acid ester copolymer; (meth)acrylic acid resin; rosin-modified maleic acid resin; olefin-based resins such as polyethylene and polypropylene; polycarbonate; polyether-based resin; (modified) polyphenylene ether; vinyl-based resins such as polyvinyl chloride and polyvinylidene chloride; urethane-based resin; phenolic resin; epoxy-based resin; polyphenylene oxide-based resin; terpene phenolic resin; polylactic acid resin; hydrogenated rosin; cyclized rubber; ionomer resin; silicone resin; ketone resin; xylene resin; ABS resin; cycloolefin-based copolymer resin; petroleum-based resin; and hydrogenated petroleum-based resin. These amorphous resins can be used alone or in combination in any ratio. Among these, polyester and styrene-(meth)acrylic acid copolymer resins are preferred from the viewpoint of being able to satisfy the requirements for the toner image quality, durability, productivity, etc. in a well-balanced manner.

[0037] The weight average molecular weight (Mw) of the amorphous resin is preferably 5,000 to 60,000, more preferably 8,000 to 40,000. The weight average molecular weight (Mw) of the amorphous resin can be determined by the GPC measurement described above. In addition, in the molecular weight distribution curve of the amorphous resin measured by GPC, the molecular weight (Mw) of the amorphous resin is 1×10 ５ ~1 x 10 ７ In this case, it is preferable that the peak top of the peak Sp in the molecular weight distribution curve of the toner is in the range of 1×10 ５ ~1 x 10 ７ It is easy to adjust the range of

[0038] The melting point of the amorphous resin is preferably 50°C or higher and lower than 180°C, more preferably 60°C or higher and lower than 170°C, and even more preferably 70°C or higher and lower than 160°C. When the melting point of the amorphous resin is within this range, the fixing property and anti-fusing property are good, and further, the moldability is also good. The melting point of the amorphous resin can be determined in the same manner as the melting point of the crystalline polyester.

[0039] The glass transition temperature (Tg) of the amorphous resin is preferably 30 to 80°C, more preferably 40 to 70°C. When the glass transition temperature (Tg) of the amorphous resin is within this range, the anti-fusing property and heat storage stability are good, and the fixing strength is also excellent. The glass transition temperature (Tg) of the amorphous resin can be determined in the same manner as the glass transition temperature (Tg) of the crystalline polyester.

[0040] 1-2. Wax The toner may contain a wax. The wax is not particularly limited as long as it provides good dispersibility between the crystalline polyester and the amorphous resin. Examples of the wax include polyolefin waxes such as polyethylene wax, polypropylene wax, and modified polyethylene wax; synthetic waxes such as Fischer-Tropsch wax and polyester-based synthetic wax; petroleum waxes such as paraffin wax and microcrystalline wax; animal waxes such as beeswax and spermaceti; plant waxes such as carnauba wax, candelilla wax, and rice wax; hydrogenated oils such as hydrogenated castor oil; and mineral waxes such as montan wax, ozokerite, and ceresin. These waxes can be used alone or in combination in any ratio. Of these, animal waxes and plant waxes with low melting points are preferred from the viewpoint of low-temperature fixability. However, from the viewpoint of heat-resistant storage stability of the toner, rice wax and carnauba wax, which have not too low a melting point, are more preferred. Furthermore, rice wax is even more preferred from the viewpoint of offset resistance.

[0041] The melting point of the wax is preferably 50 to 120° C., more preferably 50 to 100° C., and even more preferably 50 to 85° C. When the melting point of the wax is within this range, the toner has good melting resistance and heat storage stability, and also good fixability and fixation strength.

[0042] The melting point of the wax is measured in accordance with ASTM D3418-82 as follows: Approximately 10 mg of sample is weighed and placed in an aluminum cell. The cell is then placed in a differential scanning calorimeter (DSC) (Seiko Instruments Inc., trade name: SCC-6200), and 50 ml of N2 gas is blown in per minute. The sample is then heated from 20°C to 200°C at a rate of 10°C per minute, held at 200°C for 10 minutes, and then cooled from 200°C to 20°C at a rate of 10°C per minute. A second heating cycle is then performed under the same conditions, and the temperature at the apex of the maximum endothermic peak is taken as the melting point.

[0043] The toner preferably contains a pigment. Examples of pigments for black toner include black pigments, and examples of pigments for color toner include magenta pigments, cyan pigments, yellow pigments, and full-color toners.

[0044] Examples of black pigments include carbon black, iron oxide, magnetite, and ferrite, and carbon black is preferred. The number-average particle size, oil absorption, pH, and other properties of the carbon black are not particularly limited. Commercially available carbon black products include, for example, REGAL 400, REGAL 660, REGAL 330, REGAL 300, REGAL SRF-S, STERLING SO, STERLING V, STERLING NS, and STERLING R manufactured by Cabot Corporation; and RAVEN H20 and RAVEN 10 manufactured by Columbia Carbon Japan. Examples of carbon black include MT-P, RAVEN 410, RAVEN 420, RAVEN 430, RAVEN 450, RAVEN 500, RAVEN 760, RAVEN 780, RAVEN 1000, RAVEN 1035, RAVEN 1060, and RAVEN 1080; and #5B, #10B, #40, #2400B, and MA-100 manufactured by Mitsubishi Chemical Corporation. These carbon blacks can be used alone or in combination in any desired ratio.

[0045] Examples of magenta pigments include C.I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48, 49, 50, 51, 52, 53, 54, 55, 57, 58, 60, 63, 64, 68, 81, 83, 87, 88, 89, 90, 112, 114, 122, 123, 163, 202, 206, 207, 209, 269; C.I. Pigment Violet 19; C.I. Bat Red 1, 2, 10, 13, 15, 23, 29, 35, and the like. These magenta pigments can be used alone or in combination in any desired ratio.

[0046] Examples of cyan pigments include C.I. Pigment Blue 2, 3, 15, 16, and 17; C.I. Vat Blue 6; and C.I. Acid Blue 45. These cyan pigments can be used alone or in combination in any ratio.

[0047] Examples of yellow pigments include C.I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 23, 65, 73, 74, 83, 93, 94, 97, 155, and 180. These yellow pigments can be used alone or in combination in any ratio.

[0048] As color pigments for full-color toners, from the viewpoint of color mixing ability and color reproducibility, it is preferable to use C.I. Pigment Red 57 and 122 as magenta pigments, C.I. Pigment Blue 15 as cyan pigments, and C.I. Pigment Yellow 17, 93, 155, and 180 as yellow pigments.

[0049] 1-4. Other Components The toner may contain various additives as needed. Examples of other components include a charge control agent, a magnetic powder, a crystal nucleating agent, externally added fine particles, a stabilizer (e.g., an ultraviolet absorber, an antioxidant, a heat stabilizer, etc.), a flame retardant, an antifogging agent, a dispersant, a plasticizer (e.g., a phthalate ester, a fatty acid-based plasticizer, a phosphate-based plasticizer, etc.), a polymer antistatic agent, a low-molecular-weight antistatic agent, a compatibilizer, a conductive agent, a filler, a flowability improver, etc.

[0050] 1-4-1. Charge Control Agent The toner for developing electrostatic images of the present embodiment may contain a charge control agent, if necessary.

[0051] Examples of positively charging charge control agents include nigrosine and its modified products with fatty acid metal salts; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate and tetrabutylammonium tetrafluoroborate; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, and dicyclohexyltin oxide; diorganotin borates such as dibutyltin borate, dioctyltin borate, and dicyclohexyltin borate; pyridinium salts, azines, triphenylmethane compounds, and low-molecular-weight polymers having cationic functional groups. These positively charging charge control agents may be used alone or in combination of two or more. Among these positively charging charge control agents, nigrosine compounds and quaternary ammonium salts are preferred.

[0052] Examples of negatively chargeable charge control agents include organometallic compounds such as acetylacetone metal complexes, monoazo metal complexes, naphthoic acid or salicylic acid-based metal complexes or metal salts, chelate compounds, and low-molecular-weight polymers having anionic functional groups. These negatively chargeable charge control agents can be used alone or in combination of two or more. Among these negatively chargeable charge control agents, salicylic acid-based metal complexes and monoazo metal complexes are preferably used.

[0053] 2. Toner Manufacturing Method 2-1. Toner Manufacturing Method The toner manufacturing method of the present embodiment is not particularly limited, but examples thereof include a method of mixing and kneading a crystalline polyester, an amorphous resin, a wax, and a pigment, and then pulverizing and classifying the resulting resin composition.

[0054] As a mixing method, known methods can be used, and examples include methods of obtaining a mixture using a mixing device such as a double cone mixer, a V-type mixer, a drum type mixer, a super mixer, a Henschel mixer, or a Nauta mixer.

[0055] The resulting mixture is kneaded to uniformly disperse the pigment and optional components in the resin, yielding a kneaded product. As a kneading method, a batch-type (e.g., pressure kneader, Banbury mixer, etc.) or continuous-type hot melt kneader can be used, but a single-screw or twin-screw continuous extruder is preferred due to its advantages, such as continuous production. A more specific hot melt kneading method involves, for example, hot melt kneading the mixture in a twin-screw extruder and extruding it from a die at the tip of the twin-screw extruder to obtain a kneaded product. The kneading temperature in a twin-screw extruder is typically 70 to 250°C, preferably 70 to 200°C, and more preferably about 90 to 200°C.

[0056] In order to sufficiently melt the crystalline polyester and improve moldability, the kneading temperature is preferably set to a temperature that is 20° C. lower than the melting point of the crystalline polyester and 30° C. higher than the melting point.

[0057] The pulverization method may include a method in which the toner is first coarsely pulverized using a crusher, hammer mill, feather mill, or the like, and then finely pulverized using a jet mill, counter jet mill, high-speed rotor rotary mill, or the like, and gradually pulverized to a predetermined toner particle size.

[0058] Examples of classification methods include methods for classifying the toner using an inertial classification method such as an elbow jet, a centrifugal classification method such as a microplex, a DS separator, or a dry air classifier to obtain a classified toner having a predetermined volume average particle size.

[0059] The inorganic fine particles and resin fine powder may be attached to the toner surface by stirring using a stirrer such as a turbine stirrer, a Henschel mixer, or a super mixer.

[0060] The content of the crystalline polyester in the toner is preferably 0.1 to 20.0% by mass, more preferably 0.5 to 15.0% by mass, and even more preferably 1.0 to 10.0% by mass, based on the total mass of the toner. Furthermore, the content of the crystalline polyester in the toner is preferably 0.5 to 10.0% by mass, based on the mass of the resin (the sum of the mass of the crystalline polyester and the mass of the amorphous resin), more preferably 1.0 to 5.0% by mass, more preferably 2.0 to 4.0% by mass, and even more preferably 2.0 to 3.0% by mass. When the content of the crystalline polyester is within this range, the fixing properties, resin strength, and anti-fusing properties are improved, and the moldability of the toner is also improved. Furthermore, since the mechanical strength of the resin is appropriate, the toner is easily pulverized and other processable, and various properties such as image quality and charging properties can be improved.

[0061] The content of the amorphous resin in the toner is preferably 50 to 90% by mass, more preferably 55 to 85% by mass, and even more preferably 60 to 80% by mass, based on the total mass of the toner. By adjusting the content of the amorphous resin, it is possible to easily control the peak top position (molecular weight (M)) of the peak Sp, the peak top height (Pt) of the peak Sp, and the molecular weight (M) of the molecular weight distribution curve of the toner. ５ The height (Pb) at the time of the toner particle size change can be adjusted. When the content of the amorphous resin is within this range, the fixing property, resin strength, and anti-fusing property are improved, and the moldability of the toner is also improved. Furthermore, since the mechanical strength of the resin is appropriate, the processability of the toner, such as pulverization, is also good, and various properties such as image quality and charging properties can be improved.

[0062] The pigment content in the toner is preferably 0.1 to 30.0% by mass, more preferably 1.0 to 25.0% by mass, and even more preferably 5.0 to 20.0% by mass, based on the mass of the total amount of the toner. When the pigment content is within this range, the image density, image quality, and toner moldability become better.

[0063] The wax content in the toner is preferably 0.1 to 30.0% by mass, more preferably 1.0 to 25.0% by mass, and even more preferably 5.0 to 20.0% by mass, based on the total mass of the toner. By adjusting the wax content, it is possible to obtain a toner having a molecular weight (M) of 1×10 ５ When the wax content is within this range, the fixing property and anti-fusing property are improved, and the moldability of the toner is also improved. Furthermore, a synergistic effect is achieved to obtain a toner that is remarkably excellent in anti-fusing property, heat storage stability, etc.

[0064] When a charge control agent is used, the content thereof is preferably 0.1 to 5.0% by mass, more preferably 0.5 to 4.0% by mass, and even more preferably 1.0 to 4.0% by mass, based on the total mass of the toner.

[0065] 2-2. Coating Resin (Shell) Formation Method The following describes a method for forming a coating resin that coats part or all of the surface of core particles, using the toner particles obtained by the above-described production method, etc. as core particles. The coating method can be a known method, such as coating the resin to be used as the coating resin by a brush coating method, a dry method, a spray drying method using a fluidized bed, a rotary drying method, or an immersion drying method using a universal mixer.

[0066] 3. Uses of the Toner The toner of the present disclosure described above has excellent fixing properties and heat-resistant storage properties, and therefore can be suitably used in various image forming devices.

[0067] <Toner Preparation> (Preparation of Crystalline Polyester) In a reaction vessel equipped with a cooling tube, heating / cooling device, thermometer, stirrer, and nitrogen inlet tube, 50.0 mol % of each of the dicarboxylic acid and diol combinations for each crystalline polyester shown in Table 1 and 1.5 parts of titanium dihydroxybis(triethanolamine) as a condensation catalyst were placed and reacted for 8 hours at 180°C under a nitrogen stream while distilling off the water produced. The dicarboxylic acids and diols used as raw materials are listed below. The temperature was then gradually raised to 220°C, and the reaction was continued for 4 hours under a nitrogen stream while distilling off the water produced, and the reaction was continued under a reduced pressure of 0.5 to 10.0 kPa to obtain the desired crystalline polyester. (Raw Materials) Dicarboxylic Acid Component Dicarboxylic Acid 1:1,10-decanedicarboxylic acid (C １２ H ２２ O ４ ) Dicarboxylic acid 2: 1,7-heptanedicarboxylic acid (C ９ H １６ O ４ ) Dicarboxylic acid 3: 1,11-undecanedicarboxylic acid (C １３ H ２４ O ４ ) Dicarboxylic acid 4: 1,8-octanedicarboxylic acid (C １０ H １８ O ４ ) Dicarboxylic acid 5: 1,9-nonanedicarboxylic acid (C １１ H ２０ O ４ ) Diol component Diol 1: 1,6-hexanediol (C ６ H １４ O ２ ) Diol 2: Methanediol (CH ４ O ２ ) Diol 3: 1,9-nonanediol (C ９ H ２０ O ２ ) Diol 4: 1,2-ethanediol (C ２ H ６ O ２ ) Diol 5: 1,3-propanediol (C ３ H ８ O ２ )

[0068] (Amorphous Resin) Polyester 1 is a polyester resin that uses terephthalic acid and trimellitic acid as the polycarboxylic acid component, bisphenol A as the diol component, and has a softening point of 145° C., an acid value of 22.0 mg KOH / g, a weight average molecular weight (Mw) of 28,000, and a Tg (shoulder) of 60° C. Polyester 2 is a polyester resin that uses terephthalic acid as the polycarboxylic acid component and bisphenol A as the diol component, and has a softening point of 95° C., an acid value of 22.0 mg KOH / g, a weight average molecular weight (Mw) of 9,400, and a Tg (shoulder) of 52° C.

[0069] (Toner Manufacturing Method) The crystalline polyester and amorphous resin obtained by the above method, wax, pigment, and charge control agent were weighed out in the amounts shown in Table 1. The components were uniformly mixed using a Henschel mixer (Mitsui Mining Co., Ltd., 20L Henschel mixer) for 2 minutes at 1500 rpm (mixing step). The resulting mixture was then melt-mixed using a twin-screw extruder (PCM-30, Ikegai Corporation) at a mixing temperature of 70 to 180°C, a rotation speed of 150 rpm, and a discharge rate of 3.5 kg / hr to obtain a plate-shaped resin composition. The cooled mixture was then coarsely pulverized using a hammer mill and finely pulverized using a jet mill (Hosokawa Micron Corporation, product name: "200APG"). The mixture was then classified using a dry air classifier (Hosokawa Micron Corporation, product name: "100ATP") to obtain classified toners of each example and comparative example having an average particle size of 6 to 8 μm. (Raw materials) Wax: Rice Wax SS-1 (manufactured by BOSO Oil & Fats Co., Ltd., melting point 77 to 86°C) Pigment: Carbon black (manufactured by CABOT Corporation, ELFTEX 430) Charge control agent: T-77 (manufactured by Hodogaya Chemical Co., Ltd.)

[0070] (GPC Analysis Method, Particularly, Method for Preparing a Molecular Weight Distribution Curve) 20.0 mg of toner was dissolved in 10.0 ml of tetrahydrofuran (THF), and the solution was centrifuged (4°C, 2000 rpm x 10 min) using a centrifuge, and the supernatant was removed. The resulting supernatant was subjected to GPC measurement under the following conditions, and a spectrum (GPC measurement results of the toner) was obtained, with the horizontal axis representing retention time and the vertical axis representing the intensity detected by a differential refractive index detector. Subsequently, separate from the GPC measurement of the toner, GPC measurement was performed on several standard polystyrenes with different molecular weights. A graph of molecular weight (M) versus retention time was prepared, and a calibration curve was prepared. The horizontal axis of the spectrum (GPC measurement results of the toner) was converted from retention time to molecular weight (log M). Furthermore, the intensity detected by the differential refractive index detector, which is the vertical axis of the spectrum (GPC measurement results of the toner), was converted into the area percentage of each peak relative to the total area of ​​all peaks in the obtained spectrum (GPC measurement results), to prepare a molecular weight distribution curve. Here, the molecular weights of the standard polystyrenes used to prepare the calibration curve were a combination of polystyrene with a molecular weight of 5,480,000, polystyrene with a molecular weight of 427,000, polystyrene with a molecular weight of 96,400, polystyrene with a molecular weight of 16,200, and polystyrene with a molecular weight of 2,630. Pt / Pb was calculated from the obtained molecular weight distribution curve. GPC measurement conditions GPC device: EXTREMA GPLC system (manufactured by JASCO Corporation) Column: Two connected Shodex 806L (manufactured by Showa Denko K.K.) Column temperature: 40°C Eluent composition: tetrahydrofuran Eluent flow rate: 1.0 mL / min Calibration standard reagent: standard polystyrene Detector: differential refractive index detector Detector temperature: room temperature

[0071] (Method for measuring the average diameter and average area of ​​domains) The toner obtained in each example and comparative example was embedded in a room temperature curing resin and cured for approximately 3 days. Section samples were prepared using an ultramicrotome EM UC6 (manufactured by Leica). After vapor phase electron staining with ruthenium tetroxide (3 hours), the sections were observed with a scanning transmission electron microscope (STEM) (JSM-7001F, manufactured by JEOL Ltd.). The observed STEM images were binarized into crystalline and amorphous portions using image analysis software (Winroof 2003). STEM measurement conditions: Acceleration voltage: 30 kV, Vacuum level: High vacuum, Analysis magnification: ×30,000, Image detector: Scanning transmission electron detector (BF mode), Sample tilt: 0°

[0072] The absolute maximum length of the crystalline portion of the binarized image was measured, and the average value was taken as the average diameter of the domain. The average area of ​​the domain was calculated by assuming the average diameter to be the equivalent circle diameter r and applying the formula for the area of ​​a circle (πr ２ ) was calculated.

[0073] (Evaluation) Low-temperature fixability The toners obtained in each example and comparative example were used as the measurement object, and unfixed images were photographed using a commercially available copier (LaserJet MFP M436n manufactured by HP). The fixing machine, which rotates in pairs, is a heat fixing roll with a surface layer made of fluororesin and a pressure fixing roll with a surface layer made of silicone rubber, and is operated at a roll pressure of 1 kg / cm. ２ The rotational speed was adjusted to 150 rpm, and the surface temperature of the heat fixing roll was changed from 90 to 120°C, and the toner image on the transfer paper having the unfixed image was fixed at each surface temperature. The fixing ability was evaluated based on the temperature at which low-temperature offset of the resulting fixed image occurred. The evaluation criteria were as follows. The results are shown in Table 1. A: Low-temperature offset occurred at less than 100°C B: Low-temperature offset occurred at 100°C or higher but less than 110°C C: Low-temperature offset occurred at 110°C or higher

[0074] Heat-Resistant Storage Properties: 10 g of the toner obtained in each Example and Comparative Example was placed in a 200 mL plastic container and placed in a thermo-hygrostat (PR-3J, manufactured by Espec Corporation) set at 50°C and 80% humidity for 48 hours, after which the container was removed. Next, three sieves with mesh sizes of 150 μm, 75 μm, and 45 μm were attached to a powder tester (PT-S, manufactured by Hosokawa Micron Corporation), and 2 g of the toner was placed on the 150 μm sieve. The vibration amplitude was adjusted to 1.0 mm using the knob on the powder tester body, and the toner was sieved for 10 seconds. The weight of the toner remaining on the sieve was measured, and the a, b, c, and cohesion values ​​were calculated using the following formulas. The results are shown in Table 1. Cohesion degree (%) = a + b + c a = (weight of toner remaining on a sieve with 150 μm openings / 2) × 100 b = (weight of toner remaining on a sieve with 75 μm openings / 2) × 100 × (3 / 5) c = (weight of toner remaining on a sieve with 45 μm openings / 2) × 100 × (1 / 5) The evaluation criteria were as follows: A: Cohesion degree is 75% or more and less than 80% B: Cohesion degree is 80% or more and less than 85% C: Cohesion degree is 85% or more

[0075] Overall Evaluation The toners of each Example and Comparative Example were evaluated overall according to the following evaluation criteria. The results are shown in Table 1. A: Both the low-temperature fixability evaluation and the heat-resistant storage stability evaluation were rated A. B: One of the low-temperature fixability evaluation and the heat-resistant storage stability evaluation was rated A and the other was rated B. C: Both the low-temperature fixability evaluation and the heat-resistant storage stability evaluation were rated B. D: Either the low-temperature fixability evaluation or the heat-resistant storage stability evaluation was rated C.

[0076] CROSS-REFERENCE TO RELATED APPLICATIONS

[0077] This application claims priority based on Japanese Patent Application No. 2023-170757, filed with the Japan Patent Office on September 29, 2023, the entire disclosure of which is incorporated herein by reference in its entirety.

Claims

1. A toner comprising a resin, a wax, and a pigment, wherein the resin comprises a crystalline polyester and an amorphous resin, and the crystalline polyester is made of a dicarboxylic acid component having 10 to 12 carbon atoms and a diol component having 2 to 8 carbon atoms as constituent raw materials.

2. The toner according to claim 1, wherein the content of the crystalline polyester is 0.5 to 10.0% by mass based on the mass of the resin.

3. The toner according to claim 1, wherein the content of the crystalline polyester is 2.0 to 4.0% by mass based on the mass of the resin.

4. The toner according to claim 1, further comprising domains consisting of said crystalline polyester and said wax, said domains having an average diameter of 75 nm or less.

5. The molecular weight distribution curve of the toner measured by gel permeation chromatography (GPC) is 1×10 ５ ~1×10 ７ and the molecular weight distribution curve includes a peak Sp having a peak top in the range of 1×10 ５ 5. The toner according to claim 1, wherein the ratio (Pt / Pb) of the height (maximum value) Pt of the peak top of the peak Sp on the vertical axis to Pb is 1.3 or more, where Pb is the vertical axis value in the molecular weight distribution curve. Note that the horizontal axis of the molecular weight distribution curve represents the molecular weight (M), and the vertical axis of the molecular weight distribution curve represents area %. The area % is the area % of each peak based on the total area of ​​all peaks in the spectrum obtained in the GPC measurement of the toner, with the horizontal axis representing the retention time and the vertical axis representing the detection intensity by a differential refractive index detector. The GPC measurement conditions are as follows: Column temperature: 40° C. Eluent composition: tetrahydrofuran Eluent flow rate: 1.0 mL / min Calibration standard reagent: standard polystyrene Detector: differential refractive index detector Detector temperature: room temperature

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