Toner containing crystalline polyester

Abstract

Provided is a toner having excellent low-temperature fixability and more excellent heat-resistant storability. A toner according to one embodiment contains a resin, a wax, and a pigment. Furthermore, the resin contains a crystalline polyester and an amorphous resin, and the crystalline polyester comprises a dicarboxylic acid component having 10-12 carbon atoms and a diol component having 2-8 carbon atoms as constituent raw materials.

Description

TECHNICAL FIELD

[0001] A toner containing a crystalline polyester is provided. BACKGROUND

[0002] An electrophotographic method is widely used as one of image forming methods in copiers, printers, facsimiles, and the like. A general image forming based on the electrophotographic method has the following processes: a developing process of forming an electrostatic latent image by irradiating a photoconductor (photoreceptor) with the same charge, which uses a contact charging roller or a corona charger utilizing corona discharge, with laser light or LED (light emitting diode) light or the like, and electrostatically adhering a toner (hereinafter, only toner is written, but the same meaning is applied) for electrostatic charge development to the electrostatic latent image to form a toner image; a transferring process of transferring the toner image to a recording medium such as a recording medium; and a fixing process of fixing the toner image after the transferring by melting the toner image on the recording medium through contact with a heat medium and infrared radiation or the like and then dissipating the heat. In recent years, in the fixing process, development of a technology capable of low-temperature fixing has been advanced from the viewpoint of energy saving. The toner excellent in low-temperature fixing property is likely to cause a blocking phenomenon in which the toner becomes hard due to heat generated from a machine used or heat during a storage period, and poor heat-resistant storage property is considered to be a problem. In view of such a problem, for example, a toner capable of balancing low-temperature fixing property and heat-resistant storage property disclosed in Patent Literature 1 has been proposed.

[0003] PRIOR ART DOCUMENT PATENT LITERATURE Patent Literature 1: Japanese Patent Application Laid-Open No. 2006-084743 SUMMARY PROBLEMS TO BE SOLVED BY THE INVENTION Patent Literature 1 discloses a toner satisfying 10°C < (T1-T2) < 60°C when a glass transition temperature before thermal fusion is set to T1 by heating from -20°C to 150°C at a temperature increase rate of 10°C / min, and a glass transition temperature after thermal fusion is set to T2 by cooling from 150°C to -20°C at a temperature decrease rate of 10°C / min and then heating at a temperature increase rate of 10°C / min, and / or satisfying 0 < Q2 / Q1 < 2 / 3 and 10°C < (T1-T2) < 60°C and 0 < Q2 / Q1 < 2 / 3 when an endothermic amount of a melting point peak before thermal fusion is set to Q1 and an endothermic amount of a melting point peak after thermal fusion is set to Q2, the toner being capable of balancing low-temperature fixing property and heat-resistant storage property. However, the toner of Patent Literature 1 contains a low-softening-point resin excellent in low-temperature fixing property or the like, and thus, although excellent in low-temperature fixing property, the heat-resistant storage property can be insufficient.

[0004] Therefore, an object of the present application is to provide a toner which is excellent in low-temperature fixing property and more excellent in heat-resistant storage property.

[0005] Means for solving the problem To solve the above-described problem to be solved, the toner of the present disclosure is characterized by containing a plurality of specific resins. That is, the present technology is as described below.

[0006] One embodiment of the present technology is: A toner containing a resin, a wax, and a pigment, the resin containing a crystalline polyester and an amorphous resin, the crystalline polyester using a dicarboxylic acid component having 10 to 12 carbon atoms and a diol component having 2 to 8 carbon atoms as a raw material.

[0007] Preferably, the content ratio of the crystalline polyester is 0.5 to 10.0% by mass based on the mass of the resin.

[0008] Preferably, the content ratio of the crystalline polyester is 2.0 to 4.0% by mass based on the mass of the resin.

[0009] Preferably, the toner further contains a domain composed of the crystalline polyester and the wax, the domain having an average diameter of 75 nm or less.

[0010] Preferably, the toner has a molecular weight distribution curve obtained by gel permeation chromatography (GPC) including a peak Sp having a peak top in a range of a molecular weight (M) of 1 x 10 5 ~1 x 10 7 , when a value of a molecular weight (M) of 1 x 10 5 of a vertical axis of the molecular weight distribution curve is set as Pb, a ratio (Pt / Pb) of a height of the peak top of the peak Sp of the vertical axis to Pb is 1.3 or more.

[0011] In addition, the horizontal axis of the molecular weight distribution curve is a molecular weight, and the vertical axis of the molecular weight distribution curve is an area%.

[0012] The area% is an area% of each peak when a total area of all peaks of a spectrum obtained in the GPC measurement of the toner is taken as a reference, the spectrum having a horizontal axis of a retention time and a vertical axis of a detection intensity obtained by a differential refractive detector.

[0013] The GPC measurement conditions are as follows: Temperature in column: 40°C Eluent component: tetrahydrofuran Eluent flow rate: 1.0 mL / min Standard reagent for calibration: standard polystyrene Detector: differential refractive detector Detector temperature: room temperature.

[0014] Effects of the Invention According to the present application, by using toner containing a plurality of specific resins, toner having excellent low-temperature fixing property and more excellent heat-resistant storage property can be provided. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 The graph is for explaining the molecular weight distribution curve of the toner. DETAILED DESCRIPTION

[0016] In the present disclosure, in the case where only the compound name is shown, all isomers thereof are included.

[0017] In the present disclosure, in the case where " (meth) acryl", " (meth) acrylic acid", and the like are shown, "acryl and / or methacryl", "acrylic acid and / or methacrylic acid", and the like are meant.

[0018] 1. Toner The toner of the present disclosure preferably contains a resin, a wax, and a pigment. In addition, the resin preferably contains a crystalline polyester and an amorphous resin, and more preferably the crystalline polyester contains a dicarboxylic acid component having 10 to 12 carbon atoms and a diol component having 2 to 8 carbon atoms as a raw material.

[0019] The structure of the toner particles constituting the toner is not particularly limited, and a toner particle of a core-shell structure, in which a particulate core of the same toner component is covered with a resin layer different from the above-mentioned toner component on part of the surface or the entire surface of the core, can be mentioned.

[0020] The average particle diameter of the toner particles is not particularly limited as long as the effects of the present embodiment are not impaired, and is preferably 3 to 18 μm, more preferably 3 to 12 μm, and further preferably 3 to 10 μm, for example. When the average particle diameter of the toner particles is in this range, the following effects can be obtained: the toner can be easily manufactured, the amount of the toner particles used at the time of printing can be suppressed, and clear printing can be obtained.

[0021] In addition, the average particle diameter of the toner particles means the volume average particle diameter, and can be measured using a commercially available device such as a Coulter Counter, and the volume average particle diameter means the 50% volume diameter.

[0022] The thickness of the shell, i.e., the resin layer, in the case where the toner particles are of a core-shell structure is not particularly limited, and for example, the lower limit of the thickness of the resin layer can 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. In addition, the upper limit of the thickness of the resin layer can be 500 nm or less, 450 nm or less, 400 nm or less, 300 nm or less, or 200 nm or less.

[0023] The material of the shell, i.e., the resin layer, in the case where the toner particles are of a core-shell structure can 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 a polyvinylidene-based 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 and a styrene-acrylic acid copolymer resin, a halogenated olefin resin such as polyvinyl chloride, a polyester resin such as a polyethylene terephthalate resin and a polybutylene terephthalate resin, a polycarbonate resin, a polyethylene resin, a polyfluorovinyl resin, a polyvinylidene fluoride resin, a polytrifluorovinyl resin, a polyhexafluoropropylene resin, a copolymer of vinylidene fluoride and an acrylic monomer, a copolymer of vinylidene fluoride and fluorovinyl, a terpolymer of tetrafluoroethylene, vinylidene fluoride and a non-fluorinated monomer, and a silicone resin.

[0024] The molecular weight distribution curve of the toner (including all components of the toner) measured by gel permeation chromatography (GPC) (refer to Figure 1 ) includes a peak Sp having a peak top in a range of a molecular weight (M) of 1 x 10 5 ~ 1 x 10 7 In a case where a value of the molecular weight (M) of the molecular weight distribution curve at 1 x 10 5 is set as Pb, a ratio (Pt / Pb) of a height of the peak top of the peak Sp to Pb is preferably 1.3 or more, more preferably 1.3 or more and 4.0 or less, and further preferably 1.3 or more and 3.0 or less. In a case where Pt / Pb is in this range, the fixing property, the heat storage property, and the moldability of the toner are good.

[0025] Further, 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 with respect to the total area of all peaks of a spectrum (a GPC measurement result) obtained in the GPC measurement of the toner, the horizontal axis of the spectrum is the retention time, and the vertical axis is the detection intensity obtained by a differential refractometer.

[0026] The GPC measurement conditions are as follows: Temperature in column: 40°C.

[0027] Eluent component: tetrahydrofuran.

[0028] Eluent flow rate: 1.0 mL / min.

[0029] Calibration standard reagent: standard polystyrene.

[0030] Detector: differential refractive index detector.

[0031] Temperature: room temperature.

[0032] A more specific example of the GPC measurement is as follows.

[0033] The 20.0 mg toner was dissolved in 10.0 mL of tetrahydrofuran (THF), and centrifugation was performed using a centrifuge (4°C, 2000 rpm x 10 minutes), and the supernatant was taken out. In the case where the toner is difficult to dissolve in THF, THF can be heated to promote dissolution of the toner. The heating temperature is not particularly limited, and can be, for example, 60°C.

[0034] The obtained supernatant was subjected to GPC measurement under the above conditions, and a spectrum (result of GPC measurement of the toner) was obtained, in which the horizontal axis was the retention time and the vertical axis was the detection intensity obtained by the differential refractive index detector.

[0035] Next, in addition to the GPC measurement of the toner, several standard polystyrenes having different molecular weights were subjected to GPC measurement, and using a calibration curve prepared by plotting the molecular weight (M) against the retention time, the horizontal axis of the spectrum (result of GPC measurement of the toner) was converted into the molecular weight (log M) according to the retention time. In addition, the vertical axis of the spectrum (result of GPC measurement of the toner), that is, the detection intensity obtained by the differential refractive index detector, was converted into the area % of each peak based on the total area of all peaks in the obtained spectrum (result of GPC measurement), and a molecular weight distribution curve was plotted.

[0036] The molecular weights of the standard polystyrenes used to plot the calibration curve are not particularly limited, and, for example, 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 in combination.

[0037] The GPC device used in the GPC measurement is not particularly limited, and, for example, an EXTREMA GPLC system (manufactured by Shimadzu Corporation) or the like can be used. In addition, the column used in the GPC measurement is not particularly limited, and a member in which two Shodex 806L (manufactured by Showa Denko K.K.) are connected can be used.

[0038] In the toner of the present disclosure, it is preferable that the toner further include domains composed of the crystalline polyester and the wax. The domains refer to a state in which the crystalline polyester and the wax form islands in the sea of the amorphous polyester to form a sea-island structure.

[0039] The average diameter of the domains in the toner is preferably 50 nm or more, 53 nm or more, 55 nm or more, etc., 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 preferably 1,700,000 nm 2 or more, 1,800,000 nm 2 or more, 1,900,000 nm 2 or more, 5,000,000 nm 2 or more, 2,300,000 nm 2 or more, 2,200,000 nm 2 or more, etc. The average area of the domains x the average number of the domains per unit area is preferably 4,200 (nm 2 / μm 2 ) or less.

[0040] By making the average diameter of the domains, the average area of the domains, and the average value of the average area of the domains x the average number of the domains per unit area in the toner within the above numerical ranges, the crystalline polyester and the wax as low-melting-point materials are suppressed from being exposed to the surface, and thus a toner having a glass transition point that is difficult to decrease and excellent heat-resistant storage properties can be obtained.

[0041] The measurement method of the average diameter of the domains, the average area of the domains, and the average value of the number of the domains per unit area in the toner will be described. First, the toner is embedded with a room-temperature curing resin to prepare a section sample. Scanning transmission electron microscope (STEM) analysis is performed on the section sample. The obtained SEM image is binarized into crystalline and amorphous portions using an image analysis software. From the crystalline portion of the binarized image, the average diameter of the domains, the average area of the domains, and the average value of the number of the domains per unit area are calculated.

[0042] 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 an endothermic peak due to melting of the crystalline component can be clearly observed in differential scanning calorimetry measurement (DSC).

[0043] The crystalline polyester preferably uses a dicarboxylic acid component having a carbon number of 10 to 12 and a diol having a carbon number of 2 to 8 as a raw material for the composition. That is, the crystalline polyester is preferably obtained by reacting a dicarboxylic acid component having a carbon number of 10 to 12 and a diol component having a carbon number of 2 to 8.

[0044] As the dicarboxylic acid component having 10 to 12 carbon atoms, no particular limitation is imposed, and aliphatic dicarboxylic acids, aromatic dicarboxylic acids, alicyclic carboxylic acids, and derivatives thereof can be given. Any one of saturated dicarboxylic acids and unsaturated dicarboxylic acids can be used. They can be used alone or in combination of a plurality of kinds in any ratio.

[0045] Among these dicarboxylic acids, aliphatic dicarboxylic acids are preferred, and 1,8-octane dicarboxylic acid, 1,9-nonane dicarboxylic acid, 1,10-decane dicarboxylic acid, structural isomers of these dicarboxylic acids, derivatives of these dicarboxylic acids are more preferred, and 1,8-octane dicarboxylic acid, 1,9-nonane dicarboxylic acid, 1,10-decane dicarboxylic acid, derivatives of these dicarboxylic acids are further preferred, and 1,8-octane dicarboxylic acid, 1,9-nonane dicarboxylic acid, 1,10-decane dicarboxylic acid are particularly preferred.

[0046] As the diol component having 2 to 8 carbon atoms, no particular limitation is imposed, and aliphatic diols, aromatic diols, alicyclic diols, aliphatic ether diols, 1,4-bis(hydroxymethyl)cyclohexane; bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A, polyoxypropylenated bisphenol A, and etherified bisphenols; other dihydric alcohol monomers and derivatives thereof; and the like can be given. Any one of saturated diols and unsaturated diols can be used. They can be used alone or in combination of a plurality of kinds in any ratio.

[0047] Among 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-heptanediol, 1,8-octanediol, neopentyl glycol, structural isomers of these diols, 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-heptanediol, 1,8-octanediol, neopentyl glycol, derivatives of these diols are further preferred, and 1,2-ethanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, neopentyl glycol are particularly preferred.

[0048] 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 found by the GPC measurement described above. In the case where the weight average molecular weight (Mw) of the crystalline polyester is in this range, the fixing property, the heat storage resistance of the toner are good, and the moldability is also good.

[0049] As for the measurement of the weight average molecular weight (Mw) of the crystalline polyester, the measurement can be performed in the same manner as the GPC measurement of the toner except that centrifugal separation is performed.

[0050] The melting point of the crystalline polyester is preferably 50°C or higher and less than 100°C, more preferably 60°C or higher and less than 90°C, and further preferably 70°C or higher and less than 85°C. In the case where the melting point of the crystalline polyester is in this range, the fixing property, heat-resistant storage property of the toner are good, and the moldability is also good.

[0051] The melting point of the crystalline polyester is determined using a DSC curve and defined in the following manner. The DSC curve is a curve at the time of temperature increase when DSC measurement is performed according to ASTM D3418-82 or JIS K7121-1987. As a specific measurement method, 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, trade name: SCC-6200), and measurement is performed while 50 ml of N2 gas is blown in for 1 minute. Then, the temperature is increased from 20°C to 110°C at a rate of 10°C per minute, and held at 110°C for 10 minutes, and the thermal history below the glass transition temperature (Tg) region of the crystalline polyester is removed. Next, the temperature is decreased from 110°C to 20°C at a rate of 10°C per minute, and held at 20°C for 10 minutes. Next, the temperature is increased from 20°C to 250°C at a rate of 10°C per minute for the second time, and the apex temperature of the endothermic peak accompanying the melting of the crystalline component is observed as the melting point in the DSC temperature increase curve at this time.

[0052] The glass transition temperature (Tg) of the crystalline polyester is not particularly limited, and is preferably 40 to 100°C, more preferably 50 to 90°C, and further preferably 60 to 80°C. In the case where the glass transition temperature (Tg) of the crystalline polyester is in this range, the fusion resistance of the toner is good, and the fixing strength and moldability of the toner are good.

[0053] The measurement of the Tg of the crystalline polyester can be performed by the following method.

[0054] About 10 mg of the sample was placed in an aluminum cell, and the cell was placed in a differential scanning calorimeter (manufactured by Seiko Instruments, product name: SCC-6200) and measured according to JIS K7121-1987 while blowing 50 ml of N2 gas for 1 minute. First, the temperature was increased at a rate of 10°C per minute between -20°C and 110°C, and the thermal history was removed by keeping the sample at 110°C for 10 minutes (to place the sample below the glass transition temperature (Tg)). Next, the temperature was decreased at a rate of 10°C per minute from 110°C to -20°C, and kept at -20°C for 10 minutes. Next, the temperature was increased at a rate of 10°C per minute from -20°C to 110°C for the second time, and the intermediate point glass transition temperature (Tmg) described in 9.3 of the above JIS K7121-1987 was calculated from the DSC temperature increase curve observed at this time, and this temperature was used as the Tg of the present embodiment.

[0055] The crystallinity of the crystalline polyester is not particularly limited as long as it is 10% or more, but from the viewpoint of improving fixing properties and moldability, it is preferably 20 to 70%, and more preferably 30 to 80%. The crystallinity can be increased by using molding conditions and a crystal nucleating agent. In addition, the crystallinity can be found by X-ray diffraction.

[0056] 1-1-2. Amorphous resin The amorphous resin can use a publicly known toner resin, and is not particularly limited, and for example, polyester resins; styrene-(meth)acrylic copolymer resins; polystyrene, poly-α-methylstyrene, polychlorostyrene, styrene-propylene copolymers, styrene-butadiene copolymers, styrene-vinyl chloride copolymers, styrene-vinyl acetate copolymers, styrene-maleic acid copolymers, styrene-acrylonitrile-acrylate copolymers, and the like styrene-based resins; (meth)acrylic resins; rosin-modified maleic acid resins; polyethylene, polypropylene, and the like olefin-based resins; polycarbonates; polyether-based resins; (modified) polyphenylene ether; polyvinyl chloride, polyvinylidene chloride resins, and the like vinyl-based resins; urethane-based resins; phenolic resins; epoxy-based resins; polyphenylene ether-based resins; terpene phenolic resins; polylactic acid resins; hydrogenated rosin; cyclized rubber; ionomer resins; silicone resins; ketone resins; xylene resins; ABS (acrylonitrile-butadiene-styrene) resins; cyclic olefin-based copolymer resins; petroleum-based resins; hydrogenated petroleum-based resins, and the like can be given. These amorphous resins can be used alone or in combination of a plurality of kinds at an arbitrary ratio. Among them, from the viewpoint of being able to balance the requirements of the toner in terms of image quality characteristics, durability, productivity, and the like, polyester, styrene-(meth)acrylic copolymer resins are preferred.

[0057] 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 described above. In addition, it is preferable that, in the molecular weight distribution curve of the amorphous resin determined by GPC, the peak top of the molecular weight (M) of the amorphous resin be in the range of 1 x 10 5 to 1 x 10 7 In this case, it is easy to adjust the peak top of the peak Sp in the molecular weight distribution curve of the toner so that the molecular weight (M) is in the range of 1 x 10 5 to 1 x 10 7

[0058] The melting point of the amorphous resin is preferably 50°C or higher and less than 180°C, more preferably 60°C or higher and less than 170°C, further preferably 70°C or higher and less than 160°C. In the case where the melting point of the amorphous resin is in this range, the fixing property, the fusion resistance, and the moldability are all good. The melting point of the amorphous resin can be determined in the same manner as the melting point of the crystalline polyester.

[0059] The glass transition temperature (Tg) of the amorphous resin is preferably 30 to 80°C, more preferably 40 to 70°C. In the case where the glass transition temperature (Tg) of the amorphous resin is in this range, the fusion resistance and the heat storage property 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.

[0060] 1-2. Wax The toner can contain a wax. As the wax, any one can be used as long as the dispersibility and the like of the crystalline polyester and the amorphous resin are good, and for example, polyolefin-based waxes such as polyethylene wax, polypropylene wax, and modified polyethylene wax; synthetic waxes such as Fischer-Tropsch wax and polyester-based synthetic wax; petroleum-based waxes such as paraffin wax and microcrystalline wax; animal-based waxes such as beeswax and whale wax; plant-based waxes such as carnauba wax, candelilla wax, and rice wax; hydrogenated oils such as hydrogenated castor oil; and mineral-based waxes such as montan wax, ozokerite, and refined ozokerite can be given. These waxes can be used alone or in combination of a plurality of kinds in any ratio. Among these waxes, from the viewpoint of low-temperature fixing property, animal-based waxes and plant-based waxes having a low melting point are preferable, from the viewpoint of heat storage property of the toner, rice wax and carnauba wax having a not-so-low melting point are more preferable, and from the viewpoint of offset resistance, rice wax is further preferable.

[0061] The melting point of the wax is preferably 50 to 120°C, more preferably 50 to 100°C, further preferably 50 to 85°C. In the case where the melting point of the wax is in this range, the fusion resistance and the heat storage property of the toner are good, and the fixing property and the fixing strength are also good.​

[0062] The melting point of the wax was measured according to ASTM D3418-82 and in the following manner.

[0063] About 10 mg of the sample was weighed into an aluminum cell and placed on a differential scanning calorimeter (DSC) (manufactured by Seiko Instruments, product name: SCC-6200) and 50 ml of N2gas was blown in for 1 minute. Then, the temperature was raised from 20°C to 200°C at a rate of 10°C per minute, held at 200°C for 10 minutes, then lowered from 200°C to 20°C at a rate of 10°C per minute, and then subjected to a second temperature rise under the above conditions, and the temperature at the top of the largest endothermic peak at this time was taken as the melting point.

[0064] 1-3. Pigment The toner preferably contains a pigment. As a pigment for a black toner, a black pigment can be given, and as a pigment for a color toner, a magenta pigment, a cyan pigment, a yellow pigment, a full-color toner, and the like can be given.

[0065] The black pigment can include carbon black, iron oxide, magnetite, ferrite, and preferably contains carbon black. The number average particle diameter, oil absorption, pH, and the like of the carbon black are not particularly limited. As commercially available products, for example, REGAL 400, REGAL 660, REGAL 330, REGAL 300, REGAL SRF-S, STERLING SO, STERLING V, STERLING NS, STERLING R manufactured by Cabot Corporation; RAVEN H20, RAVEN MT-P, RAVEN 410, RAVEN 420, RAVEN 430, RAVEN 450, RAVEN 500, RAVEN 760, RAVEN 780, RAVEN 1000, RAVEN 1035, RAVEN 1060, RAVEN 1080 manufactured by Columbia Carbon Japan; #5B, #10B, #40, #2400B, MA-100 manufactured by Mitsubishi Chemical; and the like can be given. These carbon blacks can be used alone or in combination of a plurality of them in any ratio.

[0066] As the magenta pigments, 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. Vat Red 1, 2, 10, 13, 15, 23, 29, 35, and the like can be given. These magenta pigments can be used alone or in combination of a plurality of kinds at an arbitrary ratio.

[0067] As the cyan pigments, C.I. Pigment Blue 2, 3, 15, 16, 17; C.I. Vat Blue 6; C.I. Acid Blue 45 can be given. These cyan pigments can be used alone or in combination of a plurality of kinds at an arbitrary ratio.

[0068] As the yellow pigments, 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, 180, and the like can be given. These yellow pigments can be used alone or in combination of a plurality of kinds at an arbitrary ratio.

[0069] As the color pigments for full-color toners, from the viewpoints of color mixing property and color reproducibility, C.I. Pigment Red 57, 122 is preferably used as the magenta pigments, C.I. Pigment Blue 15 is preferably used as the cyan pigments, and C.I. Pigment Yellow 17, 93, 155, 180 is preferably used as the yellow pigments.

[0070] 1-4. Other Components The toner can contain various additives as needed. As the other components, for example, charge control agents, magnetic powders, crystal nucleating agents, externally added fine particles, stabilizers (for example, ultraviolet absorbers, antioxidants, heat stabilizers, and the like), flame retardants, antifogging agents, dispersants, plasticizers (phthalic acid esters, fatty acid plasticizers, phosphoric acid plasticizers, and the like), high-molecular antistatic agents, low-molecular antistatic agents, phase solvents, conductive agents, fillers, flowability improvers, and the like are included.

[0071] 1-4-1. Charge Control Agent The electrostatic latent image developing toner of the present embodiment can contain a charge control agent as needed.

[0072] As the positively charged charge control agent, for example, nigrosin and a modified product thereof obtained from a fatty acid metal salt or the like; a quaternary ammonium salt such as tributylbenzylammonium-1-hydroxy-4-naphthalenesulfonate, tetrabutylammonium tetrafluoroborate; a diorganotin oxide such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide; a diorganotin borate such as dibutyltin borate, dioctyltin borate, dicyclohexyltin borate; a pyridine salt, an azine compound, a triphenylmethane compound, a low-molecular-weight polymer having a cationic functional group, and the like can be given. These positively charged charge control agents can be used alone or in combination with two or more kinds. Among these positively charged charge control agents, nigrosin compounds and quaternary ammonium salts are preferably used.

[0073] As the negatively charged charge control agent, for example, an organic metal compound such as an acetylacetone metal complex, a monoazo metal complex, a metal complex or a metal salt of naphthoic acid or salicylic acid; a chelate compound; and a low-molecular-weight polymer having an anionic functional group, and the like can be given. These negatively charged charge control agents can be used alone or in combination with two or more kinds. Among these negatively charged charge control agents, a salicylic acid metal complex and a monoazo metal complex are preferably used.

[0074] 2. Method for producing toner 2-1. Method for producing toner The method for producing toner of the present embodiment is not particularly limited, and a method in which a crystalline polyester, an amorphous resin, a wax, and a pigment are mixed and kneaded, and the obtained resin composition is pulverized and classified can be given.

[0075] As the mixing method, a publicly known method can be used, and a method in which a mixture is obtained using a double-cone mixer, a V-type mixer, a drum-type mixer, a super mixer, a Henschel mixer, a Nauta mixer, or the like can be given.

[0076] The obtained mixture is kneaded so that the pigment and the optional components are uniformly dispersed in the resin, and a kneaded product is obtained. As the kneading method, a batch type (for example, a pressurized kneader, a banbury mixer, or the like) or a continuous type hot melt kneader is preferably used, and from the viewpoint of advantages such as continuous production, a single- or double-shaft continuous extruder is preferably used.

[0077] As a more specific hot melt kneading method, for example, the mixture is hot melt-kneaded using a double-shaft extruder, and a kneaded product is obtained by extruding from a die at the front end portion of the double-shaft extruder. The kneading temperature of the double-shaft extruder is usually about 70 to 250°C, preferably 70 to 200°C, and more preferably about 90 to 200°C.

[0078] In order to sufficiently melt the crystalline polyester to improve moldability, the kneading temperature is preferably a temperature of 20°C or more lower than the melting point of the crystalline polyester and a temperature of 30°C or less higher than the melting point.

[0079] As the pulverization method, a method of first coarsely pulverizing using a crusher, a hammer mill, a feather pulverizer, or the like, and then finely pulverizing using a jet mill, a reverse jet mill, a high-speed rotor rotating mill, or the like, to pulverize the toner in stages to a prescribed toner particle size can be given.

[0080] As the classification method, a method of classifying the toner using a bend pipe jet of an inertia classification system, a Microplex classifier of a centrifugal force classification system, a DS separator, a dry-type air flow classifier, or the like, to obtain a classified toner having a prescribed volume average particle diameter can be given.

[0081] In addition, the inorganic fine particles and the resin fine powder can be made to adhere to the surface of the toner by stirring using a turbine stirrer, a Henschel stirrer, or a super stirrer, or the like.

[0082] The content rate 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 further preferably 1.0 to 10.0% by mass, based on the total mass of the toner. In addition, the content rate of the crystalline polyester in the toner is preferably 0.5 to 10.0% by mass, more preferably 1.0 to 5.0% by mass, more preferably 2.0 to 4.0% by mass, and further preferably 2.0 to 3.0% 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). In the case where the content of the crystalline polyester is in this range, the fixing property, the resin strength, the fusion resistance are more excellent, and the moldability of the toner is also more excellent. Also, since the mechanical strength of the resin is moderate, the processability such as pulverization of the toner is also good, and various properties such as the image quality property and the charging property are good.

[0083] The content rate of the amorphous resin in the toner is preferably 50 to 90% by mass, more preferably 55 to 85% by mass, and further preferably 60 to 80% by mass, based on the total mass of the toner. By adjusting the content of the amorphous resin, the position of the peak top of the peak Sp (molecular weight (M)), the height of the peak top of the peak Sp (Pt), the height of the molecular weight (M) of the molecular weight distribution curve of the toner at 1 x 10 5 In the case where the content of the amorphous resin is in this range, the fixing property, the resin strength, the fusion resistance are more excellent, and the moldability of the toner is also more excellent. Also, since the mechanical strength of the resin is moderate, the processability such as pulverization of the toner is also good, and various properties such as the image quality property and the charging property are good.

[0084] The content of the pigment in the toner is preferably 0.1 to 30.0% by mass, more preferably 1.0 to 25.0% by mass, and further preferably 5.0 to 20.0% by mass, based on the total mass of the toner. With the content of the pigment in this range, the image density, the image quality, and the toner formability are more excellent.

[0085] The content of the wax in the toner is preferably 0.1 to 30.0% by mass, more preferably 1.0 to 25.0% by mass, and further preferably 5.0 to 20.0% by mass, based on the total mass of the toner. By adjusting the content of the wax, the height (Pb) at the time when the molecular weight (M) of the molecular weight distribution curve of the toner is 1 x 10 5 With the content of the wax in this range, the fixing property and the fusion resistance are more excellent, and the toner formability is also more excellent. Furthermore, this synergistic effect can achieve a toner that is particularly excellent in the fusion resistance, the heat storage property, and the like.

[0086] In the case of using the charge control agent, the content of the charge control agent is preferably 0.1 to 5.0% by mass, more preferably 0.5 to 4.0% by mass, and further preferably 1.0 to 4.0% by mass, based on the total mass of the toner.

[0087] 2-2. Method for forming the coating resin (shell) A method for forming the coating resin that coats part or all of the surface of the toner particles obtained by the above production method or the like is described. As a method for coating the coating resin, a publicly known method can be used, such as a brushing method, a dry method, a spray drying method using a fluidized bed, a rotary drying method, a liquid immersion drying method using a universal mixer, or the like to coat the resin as the coating resin.

[0088] 3. Use of the toner The toner of the present disclosure described above is excellent in the fixing property and the heat storage property, and thus can be favorably used for various image forming apparatuses.

[0089] [Examples] <Preparation of toner> (Preparation of crystalline polyester) Into a reaction vessel equipped with a cooling tube, a heating and cooling device, a thermometer, a stirrer, and a nitrogen introduction tube, 50.0 mol% of each of the combinations of the dicarboxylic acid and the diol shown in Table 1 was added, and 1.5 parts of titanium bis(triethanolamine) dihydroxy as a condensation catalyst was added, and the reaction was performed at 180°C under a nitrogen stream while distilling off the generated water for 8 hours. The dicarboxylic acid and the diol used as the raw material are shown below.

[0090] Next, while slowly raising the temperature to 220°C, the generated water was distilled off under a stream of nitrogen gas, the reaction was further carried out under reduced pressure of 0.5 to 10.0 kPa for 4 hours, and a crystalline polyester of interest was obtained.

[0091] (raw material) dicarboxylic acid component dicarboxylic acid 1: 1,10-decanedicarboxylic acid (C 12 H 22 O4) dicarboxylic acid 2: 1,7-heptanedicarboxylic acid (C9H 16 O4) dicarboxylic acid 3: 1,11-undecanedicarboxylic acid (C 13 H 24 O4) dicarboxylic acid 4: 1,8-octanedicarboxylic acid (C 10 H 18 O4) dicarboxylic acid 5: 1,9-nonanedicarboxylic acid (C 11 H 20 O4) diol component diol 1: 1,6-hexanediol (C6H 14 O2) diol 2: methylenglycol (CH4O2) diol 3: 1,9-nonanediol (C9H 20 O2) diol 4: 1,2-ethanediol (C2H6O2) diol 5: 1,3-propanediol (C3H8O2) (amorphous resin) Polyester 1 is a polyester resin using terephthalic acid and trimellitic acid as a polycarboxylic acid component, using bisphenol A as a diol component, having a softening point of 145°C, an acid value of 22.0 mgKOH / g, a weight average molecular weight (Mw) of 28,000, and a Tg (shoulder) of 60°C.

[0092] Polyester 2 is a polyester resin using terephthalic acid as a polycarboxylic acid component, using bisphenol A as a diol component, having a softening point of 95°C, an acid value of 22.0 mgKOH / g, a weight average molecular weight (Mw) of 9,400, and a Tg (shoulder) of 52°C.

[0093] (method for producing toner) The crystalline polyester, the amorphous resin, the wax, the pigment, and the charge control agent obtained by the above method were weighed in the amounts described in Table 1, and the components were uniformly mixed using a Henschel mixer (manufactured by Mitsui Mining Co., Ltd., Henschel mixer 20L) under conditions of 2 minutes and 1500 rpm (mixing step). Thereafter, the resulting mixture was melt-mixed using a twin-screw extruder (PCM-30, manufactured by Kurimoto Co., Ltd.) under conditions of a kneading temperature of 70 to 180°C, a rotation speed of 150 rpm, and a discharge amount of 35 kg / hr, to obtain a resin composition in the form of a sheet.

[0094] Next, the kneaded product was coarsely pulverized using a hammer mill, and finely pulverized using a jet mill (manufactured by Hosokawa Micron Co., Ltd., trade name: "200APG"). Then, the pulverized product was classified using a dry-type air classifier (manufactured by Hosokawa Micron Co., Ltd., trade name: "100ATP"), to obtain a classified toner of the examples and the comparative examples having an average particle diameter of 6 to 8 μm.

[0095] (Starting materials) Wax: Rice wax SS-1 (manufactured by Boso oil and fat Co., Ltd., melting point 77 to 86°C) Pigment: Carbon black (manufactured by CABOT Co., Ltd., ELFTEX 430) Charge control agent: T-77 (manufactured by Hokuriko Chemical Industry Co., Ltd.) (Method for analyzing GPC. In particular, method for drawing molecular weight distribution curve) The 20.0 mg of the toner was dissolved in 10.0 ml of tetrahydrofuran (THF), and centrifuged using a centrifuge (4°C, 2000 rpm x 10 minutes), and the supernatant was taken out. The resulting supernatant was subjected to GPC measurement under the following conditions, to obtain a spectrum (result of GPC measurement of the toner), the horizontal axis of which was the retention time, and the vertical axis of which was the detection intensity obtained by a differential refractive detector.

[0096] Next, in addition to the GPC measurement of the toner, several kinds of standard polystyrenes having different molecular weights were subjected to GPC measurement, and a calibration curve prepared using a graph of the molecular weight (M) versus the retention time was used to convert the horizontal axis of the spectrum (result of GPC measurement of the toner) into the molecular weight (log M) based on the retention time. In addition, the vertical axis of the spectrum (result of GPC measurement of the toner), i.e., the detection intensity obtained by the differential refractive detector, was converted into the area % of each peak based on the total area of all peaks in the resulting spectrum (result of GPC measurement), and a molecular weight distribution curve was drawn.

[0097] The molecular weight combination of the standard polystyrene used for drawing the calibration curve was 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. The Pt / Pb was calculated from the obtained molecular weight distribution curve.

[0098] GPC measurement conditions GPC device: EXTREMA GPC system (manufactured by Shimadzu Corporation) Column: two Shodex 806L (manufactured by Showa Denko K.K.) were connected Column temperature: 40°C Eluent component: tetrahydrofuran Eluent flow rate: 1.0 mL / min Calibration standard reagent: standard polystyrene Detector: differential refractive index detector Detector temperature: room temperature (Method for measuring average diameter and average area of domains) The toner obtained in each of the examples and comparative examples was embedded with a room temperature curing resin and cured for about 3 days. A section sample was prepared by an ultramicrotome EM UC6 (manufactured by Leica). After gas phase electron staining with ruthenium tetroxide (3 hours), observation was performed using a scanning transmission electron microscope (STEM) (JSM-7001F, manufactured by JEOL Ltd.). The observed STEM image was binarized into crystalline parts and non-crystalline parts using image analysis software (Winroof 2003).

[0099] STEM measurement conditions Accelerating voltage: 30 kV Vacuum degree: high vacuum Magnification: x 30,000 Image detector: scanning transmission electron microscope (BF mode) Sample tilt: 0° The absolute maximum length of the crystalline parts of the binarized image was measured, and the average value thereof was taken as the average diameter of the domains. The average area of the domains was calculated from the average diameter assuming it as an equivalent circle diameter r according to the area formula of a circle (πr 2 ).

[0100] (Evaluation) Low temperature fixing property The toner obtained in each of the examples and comparative examples was used as a measurement object, and an unfixing image was taken using a commercially available copying machine (LaserJet MFP M436n manufactured by HP Inc.). A fixing machine in which a heat fixing roller having a surface layer formed of a fluororesin and a pressure fixing roller having a surface layer formed of silicone rubber were rotated in pairs was adjusted to a roller pressure of 1 Kg / cm2and a roller speed of 150 rpm, the surface temperature of the heat fixing roller was changed between 90°C and 120°C, and fixing of a toner image of a transfer paper having the unfixing image described above was performed at each surface temperature. The fixing property was evaluated in accordance with the occurrence temperature of low temperature offset of the fixed image obtained. The evaluation criteria were as follows. The results are shown in Table 1. A: low temperature offset occurred below 100°C; B: low temperature offset occurred above 100°C and below 110°C; C: low temperature offset occurred above 110°C. 2

[0101] Heat-resistant storage property 10 g of the toner obtained in each of the examples and comparative examples was respectively put in a plastic container having a capacity of 200 mL, and left to stand in a constant temperature and humidity chamber (PR-3J manufactured by ESPEC Corporation) set to a temperature of 50°C and a humidity of 80% for 48 hours and taken out. Next, sieves of three types having pore diameters of 150 μm, 75 μm, and 45 μm were sequentially installed to a powder tester (PT-S manufactured by Hosokawa Micron Corporation), and 2 g of the toner was put on the sieve having a pore diameter of 150 μm. The vibration amplitude was adjusted to 1.0 mm using a knob provided on the body of the powder tester, and the toner was sieved under conditions of a time of 10 seconds, and the weight of the toner remaining on the sieve was measured, and a, b, c, and the degree of aggregation were calculated in accordance with the following formula. The results are shown in Table 1.

[0102] Degree of aggregation (%) = a + b + c

[0103] a = (weight of toner remaining on the sieve having a pore diameter of 150 μm / 2) x 100 b = (weight of toner remaining on the sieve having a pore diameter of 75 μm / 2) x 100 x (3 / 5) c = (weight of toner remaining on the sieve having a pore diameter of 45 μm / 2) x 100 x (1 / 5) The evaluation criteria were as follows.

[0104] A: degree of aggregation was 75% or more and less than 80% B: degree of aggregation was 80% or more and less than 85% C: degree of aggregation was 85% or more Comprehensive evaluation The toner of each of the examples and comparative examples was comprehensively evaluated by the following evaluation criteria. The results are shown in Table 1.​

[0105] A: Both the low-temperature fixing property evaluation and the heat-resistant storage property evaluation are A B: One of the low-temperature fixing property evaluation and the heat-resistant storage property evaluation is A and the other is B C: Both the low-temperature fixing property evaluation and the heat-resistant storage property evaluation are B D: Either of the low-temperature fixing property evaluation and the heat-resistant storage property evaluation is C [Table 1]

[0106] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims priority based on Japanese Patent Application No. 2023-170757 filed on September 29, 2023, with the Japan Patent Office, the disclosure of which is incorporated herein in its entirety by reference.

Claims

1. A toner, wherein, contains a resin, a wax, and a pigment, the resin contains a crystalline polyester and an amorphous resin, the crystalline polyester uses a dicarboxylic acid component having 10 to 12 carbon atoms and a diol component having 2 to 8 carbon atoms as a raw material.

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

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

4. The toner according to claim 1, wherein, the toner further includes a domain composed of the crystalline polyester and the wax, the average diameter of the domain is 75 nm or less.

5. The toner according to any one of claims 1 to 4, wherein, The molecular weight distribution curve of the toner determined by gel permeation chromatography GPC comprises a peak Sp having a peak top in the range of a molecular weight M of 1 x 10 5 ~1 x 10 7 ~1 x 10 When the value of the molecular weight M of the molecular weight distribution curve at the longitudinal axis of 1 x 10 5 the peak top of the peak Sp is 1.3 or more, Furthermore, 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%, the area% is the area% of each peak when the total area of all peaks of a spectrum obtained in the GPC measurement of the toner is taken as a reference, the horizontal axis of the spectrum is the retention time, and the vertical axis is the detection intensity obtained by a differential refractometer, the GPC measurement conditions are as follows: temperature in the column: 40°C, eluent component: tetrahydrofuran, eluent flow rate: 1.0 mL / min, standard reagent for calibration: standard polystyrene, detector: differential refractometer, detector temperature: room temperature.

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