Toner

Abstract

This invention relates to a toner. This disclosure provides a toner that achieves both high image gloss and high image carrying capacity. The toner comprises toner particles, said toner particles comprising: a styrene-acrylic resin having units represented by formula (1); and an ester compound A, wherein ester compound A is an ester compound represented by formula (2) or formula (3); and SPb (J / cm²) as the SP value of the styrene-acrylic resin. 3 ) 1 / 2 And SPw1 (J / cm) as the SP value of ester compound A 3 ) 1 / 2 The absolute value of the difference is greater than 1.00 and less than 2.00.

Description

Technical Field

[0001] This disclosure relates to toners for recording methods such as electrophotography, electrostatic recording, and toner spraying recording. Background Technology

[0002] In recent years, image formation in electrophotography has expanded its applications from office printing to commercial printing. Commercial printing demands a wide variety of image qualities, but in particular, photophotographic printing requires high-speed output, high print rates, and high gloss images.

[0003] To achieve high-speed output of images with high print rates and high gloss, toners are required to have excellent melting properties that allow for sufficient viscosity reduction even with short-term heating.

[0004] To meet these requirements, various studies have been conducted on binder resins used in colorants. Among binder resins, styrene-acrylic resins incorporating long-chain (meth)acrylate alkyl esters have been investigated as binder resins with excellent melt properties.

[0005] Japanese Patent Application Publication No. 2014-035506 discloses a toner for developing electrostatically charged images, comprising: a styrene-acrylic resin as a binder resin having structural units derived from alkyl (meth)acrylate monomers having 8 or more and 22 or fewer carbon atoms and structural units derived from alkyl (meth)acrylate monomers having 1 or more and 7 or fewer carbon atoms; and a crystalline ester compound. It also discloses the use of pentaerythritol tetrabenzyl ester as a wax. In Japanese Patent Application Publication No. 2014-035506, a styrene-acrylic resin is used to control the affinity between the crystalline ester compound and the binder resin, thereby improving the melting characteristics of the toner. However, it becomes clear that when using the toner of Japanese Patent Application Publication No. 2014-035506 to continuously output images with high print rates, the images stick together, and there is an image bearing capacity problem. Furthermore, when pentaerythritol tetrabenzyl ester was used as a wax in the toner of Japanese Patent Application Publication No. 2014-035506, no improvement in image carrying capacity was observed.

[0006] Meanwhile, Japanese Patent Application Publication No. 2007-322477 discloses a binder resin for toners, comprising: a vinyl copolymer formed by copolymerization of a monomer component comprising 10 to 30% by mass of an alkyl (meth)acrylate monomer having 8 or more carbon atoms and 0.2 to 2% by mass of an alkylene glycol diacrylate monomer having 6 or more carbon atoms; and Fischer-Tropsch wax. In the binder resin described in Japanese Patent Application Publication No. 2007-322477, the viscosity of the image surface after fixing is increased due to the cross-linked structure formed by the alkylene glycol diacrylate monomer having 6 or more carbon atoms, and the adhesion of images to each other is inhibited. However, in the method described in Japanese Patent Application Publication No. 2007-322477, there is a problem that sufficient image gloss cannot be obtained during high-speed processing. As mentioned above, using a styrene-acrylic resin in which long-chain alkyl acrylates are introduced as a binder resin to achieve high image gloss, but it has the problem of image load-bearing capacity, and requires a high level of toner to achieve both. Summary of the Invention

[0007] This disclosure provides a toner that achieves both high image gloss and high image load.

[0008] This disclosure relates to a toner comprising toner particles, said toner particles comprising: a monostyrene-acrylic resin having a monostyrene-acrylic resin represented by formula (1); and an ester compound A, wherein the ester compound A is an ester compound represented by formula (2) or formula (3); and SPb (J / cm 3 ) 1 / 2 and SPw1 (J / cm 3 ) 1 / 2 The absolute value of the difference is greater than 1.00 and less than 2.00, SPb (J / cm 3 ) 1 / 2 SP value of styrene-acrylic resin, SPw1 (J / cm) 3 ) 1 / 2 The SP value of ester compound A is given.

[0009]

[0010] Where R 1 Represents a hydrogen atom or a methyl group, and R 2 It represents straight-chain alkyl groups with 10 to 14 carbon atoms, and

[0011]

[0012] Where R 11 To R 14 and R 21 To R 26Each of these terms independently represents a straight-chain alkyl group having 15 to 21 carbon atoms. Further features of this disclosure will become apparent from the following description of exemplary embodiments. Detailed Implementation

[0013] Preferred embodiments of this disclosure will now be described in detail.

[0014] In this disclosure, unless otherwise stated, the description of a numerical range having "to" between two numbers means a numerical range that includes the endpoints as the lower and upper limits.

[0015] The toner disclosed herein is a toner comprising toner particles, said toner particles comprising: a styrene-acrylic resin having units represented by the following formula (1); and an ester compound A, wherein

[0016] Ester compound A is an ester compound represented by formula (2) or formula (3): and

[0017] SPb(J / cm 3 ) 1 / 2 and SPw1 (J / cm 3 ) 1 / 2 The absolute value of the difference is greater than 1.00 and less than 2.00, SPb (J / cm 3 ) 1 / 2 SP value of styrene-acrylic resin, SPw1 (J / cm) 3 ) 1 / 2 The SP value of ester compound A is given.

[0018]

[0019] Where R 1 Represents a hydrogen atom or a methyl group, and R 2 It represents straight-chain alkyl groups with 10 to 14 carbon atoms, and

[0020]

[0021] Where R 11 To R 14 and R 21 To R 26 Each of the terms independently represents a straight-chain alkyl group having 15 to 21 carbon atoms. The reason why the toners of this disclosure can achieve both high image gloss and image load-bearing capacity is not yet clear, but the inventors speculate the reason is as follows.

[0022] In the unit represented by formula (1) (hereinafter also referred to as "long-chain acrylate site"), the molecular chain has high mobility. Therefore, the resin having the long-chain acrylate site has high freedom when melting and the viscosity tends to decrease easily. Therefore, when this resin is used as a binder resin for toners, the surface of the fixed image tends to become smooth easily and a high image gloss can be obtained. On the other hand, the molecular chains of the long-chain acrylate site present on the image surface after fixing have high mobility, and the part that comes into contact with the paper to be output next tends to stick to the paper easily, and in particular, in some cases, when high-speed output of high-print-rate images, the long-chain acrylate site causes image sticking. Generally, in order to suppress image sticking, it is effective to reduce the mobility of the molecular chain. Specifically, methods for reducing the mobility of the molecular chain by cross-linking between the main chain of the resin and the cross-linking agent are known.

[0023] However, resins with long-chain acrylate sites exhibit high side chain mobility, and therefore, in some cases, even with main chain crosslinking, the mobility of the side chains does not decrease, resulting in insufficient image carrying capacity. Furthermore, when image adhesion is suppressed through crosslinking between the resin main chains, the mobility of the molecular chains decreases regardless of the temperature range, and therefore tends to hinder viscosity reduction during fixing. Thus, a trade-off between image gloss and image carrying capacity has been found.

[0024] To resolve the trade-off, it is considered that structures with high degrees of freedom in the molecular chain during fixing and reduced degrees of freedom after fixing are effective.

[0025] In this disclosure, the above problems are solved by including a toner comprising: a specific styrene-acrylic resin having a long-chain acrylate moiety; and a specific ester compound A. The long-chain acrylate moiety is a unit having a straight-chain alkyl group having 10 or more but less than 14 carbon atoms, and ester compound A is an ester compound having 4 to 6 straight-chain alkyl groups having 15 or more but less than 21 carbon atoms in its molecule. Additionally, SPb (J / cm 3 ) 1 / 2 and SPw1 (J / cm 3 ) 1 / 2 The absolute value of the difference is greater than 1.00 and less than 2.00, SPb (J / cm 3 ) 1 / 2 SP value of styrene-acrylic resin, SPw1 (J / cm) 3 ) 1 / 2 is the SP value of ester compound A.

[0026] In the above structure, the SP value of the styrene-acrylic resin and ester compound A is controlled, thereby increasing the affinity between the styrene-acrylic resin and ester compound A. Therefore, the straight-chain alkyl groups present in ester compound A can interact with the straight-chain alkyl groups present in the long-chain acrylate site. The straight-chain alkyl groups present in the long-chain acrylate site and the straight-chain alkyl groups present in ester compound A have similar structures, and therefore the straight-chain alkyl groups have a structure in which they are oriented towards each other at room temperature, and the mobility of the straight-chain alkyl groups is low. Furthermore, ester compound A has multiple straight-chain alkyl groups, and therefore, the styrene-acrylic resin forms a pseudo-crosslinked structure via ester compound A, thereby reducing the mobility of the main chain. On the other hand, at high temperatures above the melting point of ester compound A, the orientation of the straight-chain alkyl groups is released, and the mobility of the straight-chain alkyl groups is high. As described above, according to the structure of this disclosure, the mobility of the straight-chain alkyl groups present in the long-chain acrylate site can be high at high temperatures, and the mobility of the straight-chain alkyl groups present in the long-chain acrylate site can be low at room temperature. In other words, the mobility of the straight-chain alkyl groups present in the long-chain acrylate site can be controlled by temperature.

[0027] As described above, in this disclosure, during fixing at higher temperatures, the linear alkyl groups present in the long-chain acrylate sites exhibit high mobility, and consequently, the viscosity of the entire resin decreases. Therefore, high image gloss can be obtained. On the other hand, when the temperature decreases after fixing, the linear alkyl groups present in the long-chain acrylate sites align with the linear alkyl groups present in ester compound A, thereby reducing the mobility of both the linear alkyl groups and the main chain. Therefore, image adhesion can be suppressed, and image load-bearing capacity is improved.

[0028] The structure of this disclosure will then be described in more detail below.

[0029] <Adhesive Resin>

[0030] The binder resin contained in the colorant particles comprises a styrene-acrylic resin having units represented by formula (1).

[0031]

[0032] Because the styrene-acrylic resin is included in the binder resin, the viscosity during fixing can be reduced, and the image gloss is improved. Furthermore, due to its combination with ester compound A (described later), image adhesion can be suppressed, and image load-bearing capacity is improved.

[0033] In equation (1), R 1 It can be a hydrogen atom or a methyl group. Additionally, in formula (1), R... 2 It is a straight-chain alkyl group with 10 to 14 carbon atoms. Because R 2The linear alkyl group is a straight-chain alkyl group, thus reducing resin viscosity. Furthermore, the straight-chain alkyl group can be oriented with the straight-chain alkyl group in ester compound A. Therefore, improved image gloss and image carrying capacity can be achieved. Additionally, when the number of carbon atoms is 10 or more, it becomes easier to achieve the effect of reducing resin viscosity and improving image gloss. When the number of carbon atoms is 14 or less, the orientation of the straight-chain alkyl group in the resin with the straight-chain alkyl group in ester compound A occurs preferentially over the orientation of the straight-chain alkyl group in the resin with each other, thus improving image carrying capacity. More preferably, R... 2 The straight-chain alkyl group represents 12 carbon atoms.

[0034] Preferably, the styrene-acrylic resin is a styrene-acrylic resin having 1 to 15% by mass of units represented by formula (1) based on the total mass of the styrene-acrylic resin. When the content of units represented by formula (1) is 1 to 15% by mass, a sufficient effect of reducing viscosity is obtained, and the image gloss is thereby improved. In addition, the orientation of the linear alkyl groups present in the long-chain acrylate sites is suppressed, and the image carrying capacity is thus improved. More preferably, the styrene-acrylic resin is a styrene-acrylic resin containing 2 to 10% by mass of units represented by formula (1) based on the total mass of the styrene-acrylic resin.

[0035] In addition to the unit represented by formula (1), the styrene-acrylic resin also contains the unit represented by formula (7). Preferably, the styrene-acrylic resin contains the unit represented by formula (7) in an amount of 1 to 99% by mass, and more preferably in an amount of 50 to 90% by mass.

[0036]

[0037] In equation (7), R 61 It represents a hydrogen atom or a methyl group.

[0038] When the SP value of styrene-acrylic resin is changed from SPb (J / cm) 3 ) 1 / 2 When expressed, from the viewpoint of facilitating increased affinity with ester compound A as will be described later, it is preferable that SPb is 19.50 or more and 20.40 or less. More preferably, SPb is 19.80 or more and 20.10 or less. SPb can be controlled by the type and amount of units constituting the styrene-acrylic resin, etc.

[0039] Preferably, the weight-average molecular weight of the styrene-acrylic resin is 10,000 or more and 500,000 or less. The weight-average molecular weight can be controlled by factors such as the reaction temperature and the amount of initiator during the production of the styrene-acrylic resin.

[0040] Preferably, the glass transition temperature of the styrene-acrylic resin is above 40°C and below 60°C. The glass transition temperature can be controlled by the type and amount of the units constituting the styrene-acrylic resin.

[0041] Preferably, the binder resin contained in the toner particles comprises 80% by weight or more of a styrene-acrylic resin. Additionally, the binder resin contained in the toner particles may be used in conjunction with conventionally known resins without particular limitation, as needed. Examples of binder resins that can be used with styrene-acrylic resins include vinyl resins, polyester resins, polyurethane resins, and polyamide resins, in addition to styrene-acrylic resins.

[0042] <polymerizable monomers>

[0043] Styrene-acrylic resins can be obtained by polymerization. Examples of polymerizable monomers that form units represented by formula (1) in styrene-acrylic resins include acrylates and methacrylates such as decyl acrylate, decyl methacrylate, lauryl acrylate, lauryl methacrylate, myristyl acrylate, and myristyl methacrylate. Among these esters, lauryl acrylate or lauryl methacrylate is preferred.

[0044] Furthermore, the polymerizable monomers forming the styrene-acrylic resin represented by formula (7) are styrene and α-methylstyrene. Styrene is preferred over styrene. In addition to the units represented by formulas (1) and (7), the styrene-acrylic resin may also have units derived from commonly known polymerizable monomers without particular limitation. Examples of polymerizable monomers include: monofunctional monomers having one polymerizable unsaturated bond in the molecule, including acrylates such as methyl acrylate and n-butyl acrylate; methacrylates such as methyl methacrylate, 2-hydroxyethyl methacrylate, tert-butyl methacrylate, and 2-ethylhexyl methacrylate; unsaturated carboxylic acids such as acrylic acid and methacrylic acid; unsaturated dicarboxylic acids such as maleic acid; unsaturated dicarboxylic anhydrides such as maleic anhydride; nitrile vinyl monomers such as acrylonitrile; halogenated vinyl monomers such as vinyl chloride; and nitro vinyl monomers such as nitrostyrene; and polyfunctional monomers having multiple polymerizable unsaturated bonds in the molecule, such as divinylbenzene, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, and trimethylolpropane tri(meth)acrylate. Among the monomers, acrylates or methacrylates are preferred, and n-butyl acrylate is more preferred.

[0045] <Ester compound A>

[0046] The toner particles comprise an ester compound A represented by formula (2) or formula (3).

[0047]

[0048]

[0049] In equations (2) and (3), R 11 To R 14 and R 21 To R 26 Each of these can be used independently to represent a straight-chain alkyl group having 15 to 21 carbon atoms.

[0050] The combination of ester compound A and styrene-acrylic resin can suppress image adhesion and improve image load-bearing capacity.

[0051] When the SP value of ester compound A is defined as SPw1 (J / cm) 3 ) 1 / 2 At that time, SPb(J / cm 3 ) 1 / 2 and SPw1 (J / cm 3 ) 1 / 2 The absolute value of the difference is greater than 1.00 and less than 2.00, SPb (J / cm 3 ) 1 / 2 SP value of styrene-acrylic resin, SPw1 (J / cm) 3 ) 1 / 2 The SP value of ester compound A is used. When the absolute value of this difference is 1.00 or more and 2.00 or less, the affinity between ester compound A and styrene-acrylic resin is increased, and ester compound A can interact with styrene-acrylic resin; thus, image carrying capacity is improved. The absolute value of the difference between SPw1 and SPb is more preferably 1.50 or more and 1.90 or less. On the other hand, when the absolute value of the difference between SPw1 and SPb is less than 1.00, the affinity between ester compound A and styrene-acrylic resin is too high, and therefore ester compound A does not separate during fixing; and the effect of reducing viscosity becomes insufficient. In addition, when the absolute value of the difference between SPw1 and SPb exceeds 2.00, ester compound A and styrene-acrylic resin do not interact with each other, and therefore, the effect of improving image carrying capacity cannot be obtained. Therefore, SPw1 is preferably 18.00 or more and 18.50 or less. More preferably, SPw1 is 18.10 or more and 18.40 or less. SPw1 can be controlled by the number of carbon atoms in the straight-chain alkyl group and the number of ester bonds present in ester compound A.

[0052] When the number of carbon atoms of the straight-chain alkyl group present in ester compound A is represented by C1, and the number of carbon atoms of the straight-chain alkyl group present in the unit represented by formula (1) is represented by C2, the following expression (a) is preferably satisfied.

[0053] 4≤C1-C2≤10 (a)

[0054] When C1 and C2 satisfy expression (a), even if the ester compound A is oriented with the styrene-acrylic resin before fixing, the orientation is easily released during the heating process during fixing, and the effect of reducing viscosity can be sufficiently obtained. Therefore, it becomes easier to obtain the effect of improving image gloss. In addition, orientation becomes easier to occur during cooling, and the image carrying capacity is further improved. More preferably, C1 and C2 satisfy the following expression (a').

[0055] 6≤C1-C2≤10(a')

[0056] Preferably, ester compound A is an ester compound represented by formula (2') or formula (3').

[0057]

[0058] In equations (2') and (3'), R 11 To R 14 and R 21 To R 26 Each of these can be used independently to represent a straight-chain alkyl group having 17 to 21 carbon atoms.

[0059] When ester compound A is an ester compound represented by formula (2') or formula (3'), ester compound A partially separates during fixing and acts as a release agent, thus improving the release properties of the image. More preferably, ester compound A is an ester compound represented by formula (2'). The ester compound represented by formula (2') has high mobility, and its dispersibility in the image is improved during the period from fixing to cooling. Therefore, styrene-acrylic resin can form a pseudo-crosslinked structure more uniformly via the ester compound represented by formula (2'). Consequently, the uniformity of image gloss is improved.

[0060] Examples of ester compound A include pentaerythritol tetrapalmitate, pentaerythritol tetrastearate, pentaerythritol tetraeicosanoate, pentaerythritol tetrabenzyl ester, dipentaerythritol hexapalmitate, dipentaerythritol hexastearate, dipentaerythritol hexaeicosanoate, and dipentaerythritol hexabenzyl ester.

[0061] The melting point of ester compound A is preferably 70°C or higher and 90°C or lower, more preferably 75°C or higher and 90°C or lower, and even more preferably 75°C or higher and 85°C or lower.

[0062] The molecular weight of ester compound A is preferably 1,000 or more and 2,200 or less, and more preferably 1,200 or more and 2,200 or less.

[0063] The content of ester compound A is preferably 1.0 part by weight or more and 20.0 part by weight or less of the binder resin contained in 100.0 parts by weight of the colorant particles, more preferably 2.0 part by weight or more and 15.0 part by weight or less, and even more preferably 3.0 part by weight or more and 12.0 part by weight or less.

[0064] <Ester compound B>

[0065] Preferably, the toner particles comprise an ester compound B as represented by formula (4), (5), or (6), and SPb (J / cm) 3 ) 1 / 2 and SPw2 (J / cm 3 ) 1 / 2 The absolute value of the difference is less than 2.10, SPb (J / cm 3 ) 1 / 2 SP value of styrene-acrylic resin, SPw2 (J / cm) 3 ) 1 / 2 The SP value of ester compound B is given.

[0066]

[0067] In equations (4), (5), and (6), R 31 and R 41 Each independently represents an alkylene group having 2 to 8 carbon atoms, and R 32 R 33 R 42 R 43 R 51 and R 52 Each can be used independently to represent a straight-chain alkyl group having 14 to 24 carbon atoms.

[0068] Ester compound B exhibits high compatibility with styrene-acrylic resins, and therefore can achieve a viscosity reduction effect at low temperatures. Consequently, high image gloss can be obtained even when the toner is fixed at low temperatures.

[0069] Examples of compounds represented by formula (4) include ethylene glycol dispalmitate, ethylene glycol distearate, ethylene glycol eicosanoate, ethylene glycol disabarate, ethylene glycol docosuccinate, butylene glycol distearate, butylene glycol disabarate, hexanediol distearate, hexanediol disabarate, octyl glycol distearate, and octyl glycol disabarate. Examples of compounds represented by formula (5) include distearate succinate, disabarate succinate, distearate adipate, disabarate adipate, distearate octanoate, disabarate octanoate, distearate sebacic acid, and disabarate sebacic acid. Examples of compounds represented by formula (6) include palmitate palmitate, stearate palmitate, benzyl palmitate, palmitate stearate, stearate stearate, benzyl stearate, palmitate benzyl palmitate, stearate benzyl palmitate, and benzyl palmitate.

[0070] Preferably, ester compound B is an ester compound represented by formula (4) or formula (5), because this ester compound readily improves compatibility with styrene-acrylic resins having units represented by formula (1). Ester compounds represented by formula (4) or formula (5) have a linear structure and therefore exhibit rapid melting characteristics; and have multiple ester bonds in the molecule, thus tending to readily control the difference in SP value with styrene-acrylic resins. Therefore, the effect of reducing the viscosity of the toner is further improved.

[0071] More preferably, ester compound B is an ester compound represented by formula (4') or formula (5').

[0072]

[0073] In equations (4') and (5'), R 31 and R 41 Represents ethylene, and R 32 R 33 R 42 and R 43 Each can be used independently to represent a straight-chain alkyl group having 16 to 22 carbon atoms.

[0074] Preferably, SPb (J / cm) 3 ) 1 / 2 and SPw2 (J / cm 3 ) 1 / 2 The absolute value of the difference between SPb and SPw2 is 2.10 or less. When the absolute value difference between SPb and SPw2 is 2.10 or less, ester compound B becomes readily compatible with styrene-acrylic resins, and therefore, high image gloss can be obtained even when the toner is fixed at low temperature. More preferably, the absolute value of the difference between SPb and SPw2 is 2.00 or less.

[0075] From the viewpoint of easily improving affinity with styrene-acrylic resins, it is preferable that SPw2 is 17.90 or higher and 18.50 or lower. More preferably, SPw2 is 18.00 or higher and 18.20 or lower.

[0076] Furthermore, it is preferable that SPw2 is lower than SPw1. When SPw2 is lower than SPw1, when the temperature decreases after fixing, the straight-chain alkyl groups present in the long-chain acrylate sites preferentially orient with ester compound A rather than ester compound B, and therefore, it becomes easier to obtain an effect that improves image carrying capacity. SPw2 can be controlled by the number of carbon atoms and the number of ester bonds of the straight-chain alkyl groups present in ester compound B.

[0077] The melting point of ester compound B is preferably 65°C or higher and 90°C or lower, and more preferably 70°C or higher and 85°C or lower.

[0078] Preferably, the melting point of ester compound B is lower than that of ester compound A. When the melting temperature of ester compound B is lower than that of ester compound A, ester compound B melts first during the heating process of fixing, and thus the effect of reducing viscosity is improved; and during the temperature reduction process after fixing, the mobility of ester compound A decreases first, and thus the effect of improving image carrying capacity is improved.

[0079] The molecular weight of ester compound B is more preferably 500 or more and 900 or less, and more preferably 550 or more and 850 or less.

[0080] As can be seen from the above, it is more preferable to use ethylene glycol distearate as ester compound B.

[0081] The content of ester compound B is preferably 1.0 part by weight or more and 40.0 part by weight or less of the binder resin contained in 100.0 parts by weight of the colorant particles, more preferably 3.0 part by weight or more and 30.0 part by weight or less, and even more preferably 5.0 part by weight or more and 25.0 part by weight or less.

[0082] Subsequently, in the materials that can be used for toner particles, internal additives other than those mentioned above will be described in detail.

[0083] <Mold Release Agent>

[0084] In addition to styrene-acrylic resins, ester compounds A and B having units represented by formula (1), the toner particles may also contain known waxes as release agents.

[0085] Examples of release agents include: petroleum-based waxes and their derivatives, represented by paraffin, microcrystalline wax, and petrolatum; lignite waxes and their derivatives; hydrocarbon waxes and their derivatives produced via the Fischer-Tropsch process; polyolefin waxes and their derivatives, represented by polyethylene; and natural waxes and their derivatives, represented by carnauba wax and candelilla wax, wherein the derivatives include oxides, block copolymers with vinyl monomers, and graft-modified products. These release agents can be used alone or in combination.

[0086] <Coloring agent>

[0087] Toner particles may contain colorants. As colorants, conventionally known pigments and dyes of black, yellow, magenta, and cyan, as well as other colors, and magnetic materials, can be used without particular limitation.

[0088] Examples of black colorants include black pigments such as carbon black.

[0089] Examples of yellow colorants include yellow pigments and dyes, such as monoazo compounds; diazo compounds; condensed azo compounds; isoindolinone compounds; benzimidazolone compounds; anthraquinone compounds; azo metal complexes; methine compounds; and allylamide compounds.

[0090] Specific examples include: CI Pigment Yellow 74, 93, 95, 109, 111, 128, 155, 174, 180 and 185; and CI Solvent Yellow 162.

[0091] Examples of magenta colorants include magenta pigments and dyes, such as monoazo compounds; condensed azo compounds; pyrrolopyrroledione compounds; anthraquinone compounds; quinacridone compounds; basic dye lake compounds; naphthol compounds; benzimidazolone compounds; indigo thiocyanate compounds; and perylene compounds.

[0092] Specific examples include: CI Pigment Red 2, 3, 5, 6, 7, 23, 48:2, 48:3, 48:4, 57:1, 81:1, 122, 144, 146, 150, 166, 169, 177, 184, 185, 202, 206, 220, 221, 238, 254 and 269; and CI Pigment Violet 19.

[0093] Examples of cyan colorants include cyan pigments and dyes, such as copper phthalocyanine compounds and their derivatives; anthraquinone compounds; and basic dye lake compounds.

[0094] Specific examples include CI Pigment Blue 1, 7, 15, 15:1, 15:2, 15:3, 15:4, 60, 62 and 66.

[0095] Preferably, the content of the colorant is 1.0 parts by weight or more and 20.0 parts by weight or less relative to 100.0 parts by weight of the binder resin contained in the colorant particles or the polymerizable monomer used to obtain the binder resin.

[0096] In addition, toners can be formed into magnetic toners by incorporating magnetic materials.

[0097] In this case, magnetic materials can also be used as colorants.

[0098] Examples of magnetic materials include: iron oxides represented by magnetite, hematite, and ferrite; metals represented by iron, cobalt, and nickel; alloys of these metals with metals such as aluminum, cobalt, copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, and vanadium; and mixtures thereof.

[0099] When magnetic materials are used as colorants, it is preferable that the content of magnetic materials is 30.0 parts by weight or more and 100.0 parts by weight or less of the binder resin contained in 100.0 parts by weight of the colorant particles.

[0100] <Charge Control Agent>

[0101] Toner particles may contain charge control agents. Known charge control agents can be used without any particular limitations.

[0102] Examples of negative charge control agents include: metal compounds of aromatic carboxylic acids such as salicylic acid, alkyl salicylic acid, dialkyl salicylic acid, naphtholic acid, and dicarboxylic acid, or polymers or copolymers of metal compounds having aromatic carboxylic acids; polymers or copolymers having sulfonic acid groups, sulfonate groups, or sulfonate groups; metal salts or metal complexes of azo dyes or azo pigments; and boron compounds, silicon compounds, and calixarenes. On the other hand, examples of positive charge control agents include: quaternary ammonium salts; polymeric compounds having quaternary ammonium salts in their side chains; guanidine compounds; aniline black compounds; and imidazole compounds. For reference, examples of usable polymers or copolymers having sulfonate groups or sulfonate groups include: homopolymers of vinyl monomers containing sulfonic acid groups, such as styrene sulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, 2-methacrylamido-2-methylpropanesulfonic acid, vinyl sulfonic acid, and methacrylic acid sulfonic acid; or copolymers of vinyl monomers and vinyl monomers containing sulfonic acid groups as described in the adhesive resin section.

[0103] Preferably, the charge control agent content is 0.01 parts by weight or more and 5.0 parts by weight or less relative to 100.0 parts by weight of binder resin contained in the colorant particles.

[0104] <External Additives>

[0105] The colorant disclosed herein may contain external additives.

[0106] As an external additive, conventionally known external additives can be used without particular restrictions.

[0107] Examples of external additives include: raw silica particles such as wet silica and dry silica, and surface-treated silica particles that have undergone surface treatment by agents such as silane coupling agents, titanium coupling agents, or silicone oil; metal oxide particles, represented by titanium oxide particles, aluminum oxide particles, and zinc oxide particles, or metal oxide particles that have undergone hydrophobic treatment; fatty acid metal salts, represented by zinc stearate and calcium stearate; metal complexes of aromatic carboxylic acids, represented by salicylic acid, alkyl salicylic acid, dialkyl salicylic acid, naphtholic acid, and dicarboxylic acid; clay minerals, represented by hydrotalcite; and fluorinated resin particles, represented by vinylidene fluoride particles and polytetrafluoroethylene particles.

[0108] Among the external additives, clay minerals, such as hydrotalcite, are preferred. Clay minerals have high water retention, and therefore, the presence of clay minerals on the image surface after fixing can inhibit the image surface from deteriorating due to drying, which becomes particularly significant in high-print-rate images. This effect is particularly easy to obtain when a highly hydrophobic resin, such as the styrene-acrylic resin disclosed herein, is used as the binder resin for the toner particles.

[0109] Furthermore, from the viewpoint of fluidity and electrical stability, it is preferable to use silica particles that have been treated with silicone oil as raw silica particles.

[0110] Preferably, the content of external additives in the colorant disclosed herein is 0.1 parts by mass or more and 5.0 parts by mass or less per 100 parts by mass of colorant particles.

[0111] <Average roundness of the toner>

[0112] Preferably, the average roundness of the toner is 0.940 or higher and 0.995 or lower. When the average roundness of the toner is within this range, the surface of the fixed image tends to become smoother easily, and the gloss of the fixed image is further improved. More preferably, the average roundness of the toner is 0.950 or higher and 0.995 or lower.

[0113] The method for measuring the average roundness of toners will be described later.

[0114] The method for obtaining the toner disclosed herein will then be described in detail below.

[0115] Production of Toner Granules

[0116] The colorant particles disclosed herein can be produced using known methods such as mixing and pulverizing, as well as wet production methods. From the viewpoint of particle size uniformity and shape control, wet production methods are preferred. Examples of wet production methods further include suspension polymerization, dissolution suspension polymerization, and emulsion polymerization; and emulsion polymerization is preferred because it can improve the dispersion state of ester compound A.

[0117] Specific examples of producing the colorant particles of this disclosure by emulsion aggregation include production examples having the steps (1) and (2).

[0118] (1) The preparation steps of the resin particle dispersion include polymerizing binder resin in an aqueous medium to form core particles of binder resin particles, and preparing a dispersion containing the binder resin particles.

[0119] (2) The step of forming toner particles by aggregating binder resin particles in an aqueous medium to form toner particles.

[0120] Steps (1) and (2) will be described in detail below.

[0121] (1) Preparation steps of resin particle dispersion

[0122] In the preparation step of the resin particle dispersion, binder resin particles are formed, and the binder resin particles are then used to form toner particles.

[0123] Specifically, binder resin particles are formed by the following steps: adding a monomer solution in which a polymerizable monomer for forming the binder resin, ester compound A, and, if necessary, internal additives such as ester compound B, a release agent, and a charge control agent are dissolved or dispersed in an aqueous medium containing a surfactant; applying mechanical energy thereto and forming droplets of the monomer solution; and subsequently adding a water-soluble free radical polymerization initiator thereto and causing a polymerization reaction to occur in the droplets of the monomer solution. For reference, an oil-soluble polymerization initiator may be included in the droplets of the monomer solution. During the polymerization of the binder resin, forced emulsification by applying mechanical energy can be performed. Examples of means of applying mechanical energy include means of applying strong stirring or ultrasonic vibration energy, such as homogenizers and ultrasound. When polyester resin particles are used as binder resin particles, it is acceptable to synthesize the polyester resin through a conventional polycondensation reaction and form particles from the synthesized polyester resin. Examples of methods for preparing polyester resin particle dispersions include: a method of mechanically pulverizing polyester resin and dispersing the pulverized polyester resin in an aqueous medium using a surfactant; and a phase inversion emulsification method, and any method may be used.

[0124] As the polymerizable monomer used to obtain a resin particle dispersion via emulsion polymerization, the polymerizable monomers shown in the section on polymerizable monomers above can be used. As the polymerization initiator, known polymerization initiators can be used. Details will be described in detail later.

[0125] When using surfactants in the preparation of resin particle dispersions, known surfactants can be used. Details will be described in detail later.

[0126] In addition to the binder resin and ester compound A, the toner particles may contain internal additives such as ester compound B, colorant, release agent, and charge control agent, as needed. These internal additives can be introduced into the toner particles, for example, by pre-dissolving or dispersing them in a monomer solution for binder resin formation during the preparation step of the resin particle dispersion.

[0127] In addition, such internal additives can also be introduced into the toner particles by separately preparing an internal additive particle dispersion formed solely by the internal additives during the toner particle formation step and then aggregating the internal additive particles together with the resin particles and colorant particles.

[0128] The above materials can be used as internal additives.

[0129] (2) Formation steps of toner particles

[0130] In the toner particle formation step, particles of other toner components, such as ester compound B, colorant, release agent, and charge control agent, may be aggregated together with binder resin particles and ester compound A particles, as needed.

[0131] Specific examples of methods for the aggregation and melt bonding of binder resin particles, ester compound A particles, and other internal additive particles include the following method: An agglomerant is added to an aqueous medium to a concentration above the critical aggregation concentration, and then heated to a temperature not lower than the glass transition point of the binder resin particles and ester compound A particles and not higher than the melting peak temperature of their mixture. This causes salting out of the binder resin particles, ester compound A particles, and other toner components such as colorant particles, while simultaneously, melt bonding occurs in parallel. When the toner particles grow to the desired particle size, an aggregation-stopping agent is added to stop particle growth. Furthermore, heating is continued as needed to control the particle shape.

[0132] In the toner particle formation step, it is preferable to minimize the standing time of the mixture after adding the agglomerating agent, and to rapidly heat the mixture to a temperature not lower than the glass transition point of the binder resin particles and ester compound A particles, and not higher than the melting peak temperature of the mixture. The reason for this is not yet clear, but it is believed that the state of the aggregated particles changes depending on the standing time after salting out, and problems arise such as unstable particle size distribution or changes in the surface properties of the melt-bonded particles. Preferably, the time taken to reach this temperature is typically within 30 minutes, and more preferably within 10 minutes. Furthermore, it is preferable that the heating rate is 1°C / min or higher. There is no particular upper limit to the heating rate, but from the viewpoint of suppressing the formation of coarse particles due to rapid melt bonding, it is preferable to be 15°C / min or lower. Moreover, after the reaction system temperature reaches a temperature above the glass transition point, it is important to maintain the temperature of the reaction system for a certain period of time, thereby continuing melt bonding. This allows for efficient growth and melt bonding of the core particles, and improves the durability of the finally obtained toner particles. As the agglomerating agent, known metal salts having divalent or higher metal ions can be used. The details will be described in detail below.

[0133] When a surfactant is used in the toner particle formation step, known surfactants can be used. Details will be described in detail later.

[0134] <Polymerization initiator>

[0135] When using emulsification polymerization as the polymerization initiator in the preparation step of resin particle dispersion, any known polymerization initiator can be used without particular limitation.

[0136] Examples of polymerization initiators include peroxide-based polymerization initiators represented by: hydrogen peroxide, acetyl peroxide, cumene peroxide, tert-butyl peroxide, propionyl peroxide, benzoyl peroxide, chlorobenzoyl peroxide, dichlorobenzoyl peroxide, bromomethylbenzoyl peroxide, lauroyl peroxide, ammonium persulfate, sodium persulfate, potassium persulfate, diisopropyl percarbonate, tetrahydronaphthalene hydroperoxide, 1-phenyl-2-methylpropyl-1-hydroperoxide, perphenylacetic acid-tert-butyl hydroperoxide, performic acid-tert-butyl, peracetic acid-tert-butyl, perbenzoic acid-tert-butyl, perphenylacetic acid-tert-butyl, perphenylacetic acid-tert-butyl, permethoxyacetic acid-tert-butyl, N-(3-methyl) Phenyl)perpalmitate-tert-butylbenzoyl peroxide, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxy-neopentanoate, tert-butyl peroxy-isobutyrate, tert-butyl peroxy-neopentanoate, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, and lauroyl peroxide; and azo or diazo polymerization initiators represented by: 2,2'-azobis-(2,4-dimethylpentanonitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis(cyclohexane-1-nitrile), 2,2'-azobis-4-methoxy-2,4-dimethylpentanonitrile, and azobisisobutyronitrile.

[0137] <surfactants>

[0138] As a surfactant used in the colorant particle formation step, known anionic surfactants, cationic surfactants, and nonionic surfactants can be used.

[0139] Examples of anionic surfactants include: alkyl sulfates such as sodium lauryl sulfate; polyoxyethylene alkyl ether sulfates such as sodium polyoxyethylene lauryl ether sulfate; sulfonates such as sodium dodecylbenzene sulfonate and sodium alkylnaphthalene sulfonate; and higher fatty acid salts such as sodium stearate and sodium laurylate. Examples of cationic surfactants include: quaternary ammonium salts such as dodecyl ammonium bromide, dodecyl trimethyl ammonium bromide, dodecyl pyridine chloride, dodecyl pyridine bromide, hexadecyl trimethyl ammonium bromide, lauryl trimethyl ammonium chloride, and alkylbenzyl dimethyl ammonium chloride.

[0140] Examples of nonionic surfactants include: polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether and polyoxyethylene oil-based ether; polyoxyethylene derivatives such as polyoxyethylene alkylene ether; sorbitol fatty acid esters such as sorbitol monolaurate and sorbitol monostearate; glycerol fatty acid esters such as glycerol monostearate; and polyoxyethylene fatty acid esters such as polyethylene glycol monolaurate.

[0141] The following will describe in detail examples of the measurement methods used in this specification.

[0142] <Calculation method of solubility parameter value (SP value)>

[0143] SPw1, which is the SP value of ester compound A of this disclosure, and SPw2, which is the SP value of ester compound B, are obtained in the following manner according to the calculation method proposed by Fedors.

[0144] For example, when calculating the SP value (SPw1) (J / cm) of ester compound A 3 ) 1 / 2 At that time, the evaporation energy (Δei) (J / mol) and molar volume (Δvi) (cm) of atoms and groups in the molecular structure of the ester compound. 3 The SP value ( / mol) is determined from the table in "Polym.Eng.Sci.,14(2),147-154(1974)" and calculated by the following expression (8).

[0145] Expression (8): SPw1=(ΣΔei / ΣΔvi) 1 / 2

[0146] SPb, which is the SP value of the styrene-acrylic resin disclosed herein, is obtained in the following manner according to the calculation method proposed by Fedors.

[0147] First, the SP value of the repeating unit constituting the styrene-acrylic resin is determined as follows. Here, the repeating unit constituting the styrene-acrylic resin refers to the molecular structure in which the double bonds of the styrene-acrylic monomer used in obtaining the styrene-acrylic resin by polymerization are broken.

[0148] For example, when calculating the SP value (σm) (J / cm) of a repeating unit. 3 ) 1 / 2 At that time, the evaporation energy (Δei) (J / mol) and molar volume (Δvi) (cm³) of atoms and groups in the molecular structure of the repeating unit. 3 The SP value ( / mol) is determined from the table in "Polym.Eng.Sci.,14(2),147-154(1974)" and calculated by the following expression (9).

[0149] Expression (9): σm=(ΣΔei / ΣΔvi) 1 / 2

[0150] To determine the SP value (SPb) of the styrene-acrylic resin, the evaporation energy (Δei) and molar volume (Δvi) of the repeating unit constituting the resin are determined for each repeating unit. Then, the product of each evaporation energy (Δei) and molar volume (Δvi) with the molar ratio (j) of each repeating unit in the resin is calculated, and the quotient is obtained by dividing the sum of the evaporation energies of each repeating unit by the sum of the molar volumes. The SP value is then calculated according to the following expression (10).

[0151] Expression (10): σp={(Σj×ΣΔei) / (Σj×ΣΔvi)} 1 / 2

[0152] For example, when assuming that the resin is formed from two repeating units X and Y, and when the composition ratio of the repeating units is represented by Wx and Wy (mass%), the molecular weight is represented by Mx and My respectively, the evaporation energy is represented by Δei(X) and Δei(Y), and the molar volume is represented by Δvi(X) and Δvi(Y) respectively, the molar ratio (j) of each repeating unit becomes Wx / Mx and Wy / My respectively, and the solubility parameter value (σp) of the resin is expressed by the following expression (11).

[0153] Expression (11): σp=[{(Wx / Mx)×Δei(X)+Wy / My×Δei(Y)} / {(Wx / Mx)×Δvi(X)+Wy / My×Δvi(Y)}] 1 / 2

[0154] Furthermore, when two or more resins are mixed, the SP value (σ) of the mixture... M The product of the mass composition ratio (Wi) of the mixture and the SP value (σi) of each resin is calculated and summed according to the following expression (12).

[0155] Expression (12): σ M =Σ(Wi×σi)

[0156] <Methods for separating adhesive resins and ester compounds from toners>

[0157] The toner was dissolved in tetrahydrofuran (THF); the solvent was distilled off from the obtained soluble component under reduced pressure; and the tetrahydrofuran (THF) soluble component of the toner was obtained. The obtained tetrahydrofuran (THF) soluble toner component was dissolved in chloroform, and a sample solution with a concentration of 25 mg / ml was prepared. The obtained sample solution was injected into the following apparatus in a volume of 3.5 ml, and the components were collected separately under the following conditions: the low molecular weight component derived from the release agent with a molecular weight less than 2000, and the high molecular weight component derived from the adhesive resin with a molecular weight greater than 2000.

[0158] Preparative GPC equipment: Preparative HPLC (trade name: LC-980, manufactured by Japan Analytical Industry Co., Ltd.)

[0159] Preparation columns: JAIGEL 3H and JAIGEL 5H (manufactured by Japan Analytical Industry Co., Ltd.)

[0160] Elution buffer: chloroform

[0161] Flow rate: 3.5 mL / min

[0162] After collection, the solvent was distilled off under reduced pressure, and the residue was further dried under reduced pressure at 90°C for 24 hours.

[0163] <Measuring the molecular weight of ester compounds by mass spectrometry>

[0164] • Separation of ester compounds from toners

[0165] The molecular weight of the ester compound in the toner can be determined by measuring the toner, but it is more preferable to measure it after the separation process.

[0166] The toner is dispersed in ethanol, a poor solvent for the toner, and the temperature is raised to above the melting point of the ester compound. Pressure can then be applied as needed. Through this process, the ester compound above its melting point melts and is extracted in the ethanol. When pressure is applied in addition to heating, the ester compound can be separated from the toner through solid-liquid separation under pressure.

[0167] The extract is then dried and cured, thereby obtaining the ester compound.

[0168] For example, the obtained ester compound can be pyrolyzed by GCMS using the following equipment and under the following measurement conditions; and the ester compound can be identified and its molecular weight can be measured.

[0169] Mass spectrometry analysis equipment: ISQ manufactured by Thermo Fisher Scientific KK

[0170] GC device: Focus GC manufactured by Thermo Fisher Scientific KK

[0171] Ion source temperature: 250℃

[0172] Ionization method: EI

[0173] Mass range: 50 to 1000 m / z

[0174] Column: HP-5MS [30m]

[0175] Pyrolysis equipment: JPS 700 manufactured by Japan Analytical Industry Co., Ltd.

[0176] A small amount of the ester compound, separated by extraction, and 1 μL of tetramethylammonium hydroxide (TMAH) were added to a hot foil at 590 °C. The resulting sample was subjected to pyrolysis GCMS under these conditions, and peaks of the alcohol and carboxylic acid components derived from the ester compound were obtained. At this point, the alcohol and carboxylic acid components were detected as methylated products by reaction with TMAH, which acts as a methylating agent. The molecular weight of the ester compound was determined by analyzing the obtained peaks and identifying the structure of the ester compound.

[0177] In addition, when identifying ester compounds and measuring their molecular weight by direct introduction, identification and molecular weight measurement can be performed, for example, by the following equipment and under the following measurement conditions.

[0178] Mass spectrometry analysis equipment: ISQ manufactured by Thermo Fisher Scientific KK

[0179] Ion source temperature: 250℃; Ion energy: 70eV

[0180] Mass range: 50 to 1000 m / z (CI).

[0181] Reagent gas: Methane (Cl)

[0182] Ionization method: Direct Exposure Probe (DEP) manufactured by Thermo Fisher Scientific KK, 0 mA (10 s) to 10 mA / s to 1000 mA (10 s).

[0183] The ester compounds separated by the extraction operation were placed directly onto the filament portion of the DEP unit and measured. The molecular ions of the mass spectra of the main component peaks obtained from the chromatograms at approximately 0.5 to 1 minute were examined; the ester compounds were identified, and their molecular weights were determined.

[0184] <Method for measuring the content of ester compounds in toners>

[0185] The content of ester compounds in toners can be measured using a thermal analysis device (trade name: DSC Q2000, manufactured by TA Instruments Japan Co., Ltd.).

[0186] Approximately 5.0 mg of toner sample was placed in a sample container (KITNO. 0219-0041) made of aluminum. The sample container was placed on a support unit, and the support unit was placed in an electric furnace. The sample was heated from 30°C to 200°C at a heating rate of 10°C / min under a nitrogen atmosphere. The DSC curve was measured using a differential scanning calorimeter (DSC), and the endothermic heat of the ester compound in the toner sample was calculated. Additionally, the endothermic heat of a sample containing approximately 5.0 mg of the ester compound alone was calculated using a similar method. Then, using the endothermic heat of the ester compound obtained from each measurement, the wax content was determined using the following expression.

[0187] The content (mass%) of ester compounds in a toner = (the heat endothermic of the ester compounds in the toner sample (J / g)) / (the heat endothermic of the ester compound alone (J / g)) × 100

[0188] <Compositional Analysis of Adhesive Resins>

[0189] Method for separating binder resin from toner

[0190] Dissolve 100 mg of the toner in 3 mL of chloroform. Then, filter the liquid using a syringe equipped with a sample preparation filter (pore size ≥ 0.2 μm and ≤ 0.5 μm, such as Myshori Disk H-25-2 (manufactured by Tosoh Corporation)) to remove insoluble substances.

[0191] The chloroform-soluble fraction obtained above was introduced into a preparative HPLC system (equipment: LC-9130NEXT manufactured by Japan Analytical Industry Co., Ltd., with a preparative column (60 cm) consisting of two columns connected together, with exclusion limits of 20,000 and 70,000 respectively), and chloroform was introduced as the eluent. When a peak could be detected in the obtained chromatogram, the fraction with a retention time corresponding to a molecular weight of 2000 or higher in the monodisperse polystyrene standard sample was collected separately. The obtained fraction solution was dried and cured to obtain the binder resin.

[0192] • Composition and weight ratios were measured using nuclear magnetic resonance spectroscopy (NMR).

[0193] Add 1 mL of dichloroform to 20 mg of colorant and measure the NMR spectrum of the protons of the dissolved binder resin. From the obtained NMR spectrum, calculate the molar and weight ratios of each monomer, and determine the content ratio of styrene-derived units. For example, in the case of styrene-acrylic copolymers, the composition and weight ratios can be calculated based on the peaks of styrene-derived monomers around 6.5 ppm and the peaks of acrylic monomers around 3.5 to 4.0 ppm.

[0194] For nuclear magnetic resonance spectroscopy (NMR), the following equipment and measurement conditions can be used.

[0195] NMR equipment: RESONANCE ECX500 manufactured by JEOL Ltd.

[0196] Observation nucleus: proton

[0197] Measurement mode: Single pulse

[0198] <Method for measuring the glass transition temperature (Tg) of styrene-acrylic resins>

[0199] The glass transition temperature (Tg) of the adhesive resin was measured according to ASTM D3418-82 using a differential scanning calorimeter (trade name: Q1000, manufactured by TA Instruments Com.). The melting points of indium and zinc were used for temperature calibration of the equipment's detection section, and the heat of solution of indium was used for thermal calibration. Specifically, 5 mg of styrene-acrylic resin was accurately weighed and placed in an aluminum pan, with an empty aluminum pan used as a reference. Measurements were taken over a measurement range of 30 to 200 °C at a heating rate of 1 °C / min. During this heating process, the change in specific heat was obtained in the temperature range of 40 °C to 100 °C. The glass transition temperature (Tg) of the styrene-acrylic resin was defined as the intersection of the differential thermal curve and the line connecting the baselines before and after the change in specific heat.

[0200] <Method for measuring the average roundness of toners and toner particles>

[0201] The average roundness of the toner and toner particles was measured and analyzed by a flow cytometer particle image analyzer (trade name: FPIA-3000, manufactured by Sysmex Corporation) under the following conditions.

[0202] The specific measurement method is as follows. First, put 20 ml of ion-exchanged water that has been pre-removed of impurities such as solid into a container made of glass. Add 0.2 ml of a dilution solution as a dispersant (trade name: Contaminon N, manufactured by Wako Pure Chemical Industries, Ltd.: an aqueous solution with a pH of 7 and containing 10% by mass of a neutral detergent for cleaning precision measuring instruments, which is formed by a nonionic surfactant, an anionic surfactant, and an organic co-aid) to the ion-exchanged water in a form of diluting it by 3 times the mass with the ion-exchanged water. In addition, add 0.02 g of the measurement sample thereto, and use an ultrasonic dispersion device to disperse the obtained liquid for 2 minutes to obtain a dispersion liquid for measurement. At this time, appropriately cool the dispersion liquid so that its temperature becomes 10 °C or higher and 40 °C or lower. As the ultrasonic dispersion device, use a tabletop ultrasonic cleaner dispersion device (e.g., "VS-150" (manufactured by Velvo-Clear Co., Ltd.)), whose oscillation frequency is 50 kHz and the electrical output is 150 W; and put a predetermined amount of ion-exchanged water into the water tank, and add approximately 2 ml of Contaminon N into the water tank.

[0203] For measurement, use a flow particle image analyzer equipped with "UPlanApro" (with a magnification of 10 times and a numerical aperture of 0.40) as the objective lens, and use a particle sheath (trade name: PSE-900A, manufactured by Sysmex Corporation) as the sheath liquid. Introduce the dispersion liquid prepared according to the foregoing steps into the flow particle image analyzer, and in the HPF measurement mode, measure 3000 toner particles in the total count mode. Then, set the binarization threshold at the time of particle analysis to 85%, limit the analysis particle size to a circular equivalent diameter of 1.985 μm or more and less than 39.69 μm, and obtain the average circularity of the toner and toner particles.

[0204] In the measurement, before starting the measurement, automatically adjust the focus using standard latex particles (e.g., diluting "RESEARCH AND TEST PARTICLES Latex Microsphere Suspensions 5200A" manufactured by Duke Scientific Corporation with ion-exchanged water).

[0205] <Measurement method of weight average particle size (D4)>

[0206] The weight average particle size (D4) of the toner particles is calculated in the following manner.

[0207] As a measuring device, a precision particle size distribution measuring device based on pore resistance and equipped with a 100 μm orifice tube is used (trade name: Coulter Counter Multisizer 3 (registered trademark), manufactured by Beckman Coulter, Inc.).

[0208] To set measurement conditions and analyze measurement data, the accompanying dedicated software (trade name: Beckman-Coulter Multisizer 3 Version 3.51, manufactured by Beckman Coulter Inc.) was used. For reference, measurements were performed with 25,000 effective measurement channels.

[0209] As the electrolyte aqueous solution used for measurement, solutions such as "ISOTON II" (manufactured by Beckman Coulter, Inc.) can be used, which are prepared by dissolving premium sodium chloride in ion-exchanged water to a concentration of 1.0% by mass.

[0210] For your reference, set up the dedicated software as follows before performing measurements and analyses.

[0211] In the dedicated software, on the "Change Standard Operating Measurement Method (SOMME)" screen, set the total count in the control mode to 50,000 particles, the number of measurements to 1, and the Kd value to the value obtained using "Standard Particle 10.0 μm" (manufactured by Beckman Coulter, Inc.). The threshold and noise level are automatically set by pressing the "Threshold / Noise Level Measurement Button". Additionally, set the current to 1600 μA, the gain to 2, the electrolyte solution to ISOTON II, and check "Flush the measuring tube after measurement".

[0212] In the "Pulse to Particle Size Conversion Setting" screen of the dedicated software, set the element spacing to logarithmic particle size, the particle size element to 256 particle size elements, and the particle size range to a value from 2μm to 60μm. The specific measurement method is as follows.

[0213] (1) Place 200.0 mL of electrolyte solution in a 250 mL round-bottom glass beaker for Multisizer 3. Place the beaker on the sample stage and rotate the stir bar counterclockwise at 24 rpm to stir the solution. Then, remove dirt and air bubbles from the nozzle using the "Venere Rinse" function of the dedicated software. (2) Place 30.0 mL of electrolyte solution in a 100 mL flat-bottom glass beaker. Add 0.3 mL of a diluted solution obtained by diluting "Contaminon N" (a 10% by mass aqueous solution of a neutral detergent for cleaning precision measuring instruments with pH 7, consisting of nonionic surfactants, anionic surfactants, and organic detergent builders) with 3 times the mass of ion-exchanged water as a dispersant. (3) Prepare an ultrasonic dispersion device "Ultrasonic Dispersion System Tetra 150" (manufactured by Nikkaki BiosCo.,Ltd.), which houses two oscillators with a phase shift of 180 degrees and an oscillation frequency of 50 kHz, and has an electrical output of 120 W. Place 3.3 L of ion-exchanged water in the water tank of the ultrasonic dispersion device, and add 2.0 mL of Contaminon N to the water tank.

[0214] (4) Place the beaker from (2) above into the beaker fixing hole of the ultrasonic dispersion device and start the ultrasonic dispersion device. Then, adjust the height of the beaker to maximize the surface resonance state of the electrolyte aqueous solution in the beaker.

[0215] (5) While the electrolyte solution in the beaker from step (4) is being irradiated with ultrasound, 10 mg of toner particles are gradually added to the electrolyte solution and dispersed therein. Then, the ultrasonic dispersion treatment continues for another 60 seconds. For reference, during ultrasonic dispersion, the water temperature in the tank should be appropriately adjusted to be above 10°C and below 40°C.

[0216] (6) Using a pipette, add the electrolyte aqueous solution of (5) above, which has dispersed the toner particles, dropwise into the round-bottom flask of (1) above placed on the sample stage, and adjust the measurement concentration to 5%. Then, perform the measurement until the number of particles measured reaches 50,000.

[0217] (7) Analyze the measurement data using the dedicated software attached to the equipment and calculate the weight-average particle size (D4). For reference, when the graph / volume % is set in the dedicated software, the "Average Size" on the "Analysis / Volume Statistics (Arithmetic Mean)" screen is the weight-average particle size (D4).

[0218] [Example]

[0219] In the following embodiments, the number of portions is based on mass portions.

[0220] <Example of preparation steps for resin particle dispersion>

[0221] <Preparation of Resin Particle Dispersion 1>

[0222] · 81.0 parts of styrene

[0223] 13.0 parts of n-butyl acrylate

[0224] ·6.0 parts lauryl acrylate

[0225] · 3.2 parts of lauryl mercaptan

[0226] The above materials were mixed and dissolved together. 1.5 parts of an aqueous solution of NEOGEN RK (manufactured by DKSCo., Ltd.) dissolved in 150 parts of ion-exchanged water was added and dispersed in this solution. Additionally, 0.3 parts of an aqueous solution of potassium persulfate dissolved in 10 parts of ion-exchanged water was added, while the mixture was slowly stirred for 10 minutes. After purging the system with nitrogen, emulsification polymerization was carried out at 70°C for 6 hours. After polymerization, the reaction solution was cooled to room temperature, and ion-exchanged water was added; a resin particle dispersion 1 was obtained, wherein the solid content concentration was 20.0% by mass and the median particle size based on volume was 0.2 μm. The SP value (SPb) of the obtained styrene-acrylic resin was 20.00 (J / cm²). 3 ) 1 / 2 Furthermore, its glass transition temperature (Tg) is 56℃.

[0227] <Preparation of Resin Particle Dispersions 2 to 11>

[0228] Except for the changes in materials used as shown in Table 1 below, resin particle dispersions 2 to 11 were obtained in the same manner as in the preparation example of resin particle dispersion 1.

[0229] [Table 1]

[0230]

[0231] In Table 1, St represents styrene, n-BA represents n-butyl acrylate, LA represents lauryl acrylate, n-OA represents n-octyl acrylate, n-DA represents n-decyl acrylate, MA represents myristyl acrylate, and PA represents palmitate acrylate; and the values ​​for these chemicals are expressed in parts.

[0232] <Example of preparation steps for ester compound A dispersion>

[0233] <Preparation of Ester Compound A Dispersion 1>

[0234] · Pentaerythritol tetrabenzyl ester 100.0 parts

[0235] ·NEOGEN RK 15.0 copies

[0236] · 385.0 parts of ion-exchanged water

[0237] The above materials were mixed and dispersed using a wet jet mill (trade name: JN100, manufactured by Jokoh Co., Ltd.) for approximately 1 hour to obtain ester compound A dispersion 1. The concentration of ester compound A dispersion 1 was 20% by mass.

[0238] <Preparation of Ester Compound A Dispersions 2 to 6>

[0239] Except for the changes in materials used as shown in Table 2 below, dispersions 2 to 6 of ester compound A were obtained in the same manner as in the preparation example of dispersion 1 of ester compound A. The concentration of any dispersion was 20% by mass.

[0240] [Table 2]

[0241] Ester compound A Abbreviation structure Alkyl carbon number <![CDATA[SP value (J / cm 3 ) 1 / 2 > Melting point (°C) Ester compound A dispersion 1 Pentaerythritol tetrasappan ester PE22 Equation (2') 21 18.15 82 Ester compound A dispersion 2 Pentaerythritol tetrastearate PE18 Equation (2') 17 18.27 77 Ester compound A dispersion 3 Dipentaerythritol hexasobate DP22 Equation (3') 21 18.21 87 Ester compound A dispersion 4 Pentaerythritol tetrapalmitate PE16 Equation (2) 15 18.40 74 Ester compound A dispersion 5 Dipentaerythritol hexastearate DP18 Equation (3') 17 18.35 78 Ester compound A dispersion 6 Dipentaerythritol hexapalmitate DP16 Equation (3) 15 18.44 73

[0242] <Preparation of Ester Compound B Dispersions 1 to 5>

[0243] Except for the changes in materials used as shown in Table 3 below, dispersions of ester compound B 1 to 5 were obtained in the same manner as in the preparation example of dispersion 1 of ester compound A. The concentration of any dispersion was 20% by mass.

[0244] [Table 3]

[0245] Ester compound B structure Alkyl carbon number <![CDATA[SP value (J / cm 3 ) 1 / 2 > Melting point (°C) Ester compound B dispersion 1 Glycol distearate Equation (4) 17 18.11 76 Ester compound B dispersion 2 Glycol dipalmitate Equation (4) 15 18.16 69 Ester compound B dispersion 3 Ethylene glycol disorbate Equation (4) 21 18.02 83 Ester compound B dispersion 4 Di-shamianite sebacic acid Equation (5) 22 17.94 73 Ester compound B dispersion 5 betaine betaine ester Equation (6) 22 17.56 73

[0246] <Example of Paraffin Dispersion Preparation>

[0247] Except that the pentaerythritol tetrastearate in the preparation example of ester compound A dispersion 1 was replaced with HNP-51 (manufactured by Nippon Seiro Co., Ltd.), the paraffin dispersion was prepared in the same manner as in the preparation example of ester compound A dispersion 1.

[0248] <Example of colorant dispersion preparation>

[0249] Carbon black (trade name: Nipex 35, manufactured by Orion Engineered Carbons SA) as a colorant in an amount of 100.0 parts, NEOGEN RK in an amount of 15 parts, and ion-exchanged water in an amount of 885.0 parts were mixed and dispersed using a wet jet mill (trade name: JN100, manufactured by Jokoh Co., Ltd.) for about 1 hour to obtain a colorant dispersion.

[0250] <Example of the formation steps of toner particles>

[0251] <Example of the formation of toner particles 1>

[0252] • Resin particle dispersion 1 100.0 parts

[0253] • Dispersion of ester compound A 1 8.0 parts

[0254] • Ester compound B dispersion 1 12.0 parts

[0255] · 8.0 parts of colorant dispersion

[0256] Using a homogenizer (product name: While stirring the above materials (T50, manufactured by IKA Company), the temperature in the container was adjusted to 30°C, and the pH of the dispersion was adjusted to 8.0 by adding a 1 mol / L sodium hydroxide aqueous solution. As an agglomerating agent, while stirring at 30°C, an aqueous solution of 0.3 parts magnesium sulfate dissolved in 10 parts ion-exchanged water was added to the dispersion over 10 minutes. After the liquid was left to stand for 3 minutes, its temperature was raised to 60°C, and associative particles were formed. In this state, the particle size of the associative particles was measured using a "Coulter Counter Multisizer 3" (manufactured by Beckman Coulter, Inc.). At the time point when the weight-average particle size (D4) of the associative particles reached 6.5 μm, 0.9 parts sodium chloride and 5.0 parts NEOGEN RK were added to stop particle growth, thereby obtaining toner particle dispersion 1.

[0257] Hydrochloric acid was added to the obtained toner particle dispersion 1 to adjust the pH of the dispersion to below 1.5. The dispersion was left to stand for 1 hour while stirring, and then solid-liquid separation was performed using a pressure filter to obtain a toner cake. The toner cake was re-slurryed with deionized water to form a dispersion again, and then solid-liquid separation was performed using a pressure filter. Re-slurrying and solid-liquid separation were repeated until the conductivity of the filtrate became below 5.0 μS / cm, and the resulting filtrate was finally subjected to solid-liquid separation to obtain a toner cake. The obtained toner cake was dried using an airflow dryer and a Flash Jet dryer (manufactured by Seishin Enterprise Co., Ltd.). The drying conditions were adjusted so that the blower temperature was 90°C and the dryer outlet temperature was 40°C, and the toner cake feed rate was adjusted according to the water content of the toner cake to a rate that did not deviate from the outlet temperature of 40°C. In addition, fine and coarse powders were cut using a multi-stage classifier utilizing the wall adhesion effect to obtain toner particles 1.

[0258] The weight-average particle size (D4) and average roundness of the toner particles 1 were measured using the methods described above, and the results showed that the weight-average particle size (D4) was 6.5 μm and the average roundness was 0.965.

[0259] <Examples of the formation of toner particles 2 to 15, 18, and 20 to 26>

[0260] Except that the material used in the toner particle 1 formation example is changed to the material described in Table 4, toner particles 2 to 15, 18 and 20 to 26 are formed in the same manner as in the toner particle 1 formation example. For reference, in the toner particle 18 formation example, associated particles are formed at a temperature raised to 75°C.

[0261] The weight-average particle size (D4) and average sphericity of toner particles 2 to 15, 18, and 20 to 26 were measured using the methods described above. The results showed that the weight-average particle size (D4) of toner particles 2 to 15 and 20 to 26 was 6.5 μm, and their average sphericity was 0.965. Additionally, the weight-average particle size (D4) of toner particle 18 was 6.5 μm, and its average sphericity was 0.980.

[0262] [Table 4]

[0263]

[0264] <Example of the formation of toner particles 19>

[0265] The colorant granules 19 were prepared by pulverization in the following manner.

[0266] • Adhesive resin: a copolymer of styrene / n-butyl acrylate / laurate acrylate

[0267] (Styrene: n-butyl acrylate: lauryl acrylate in a mass ratio of 81:13:6, and Tg = 56℃): 100.0 parts

[0268] • Carbon black (trade name: Nipex 35, manufactured by Orion Engineered Carbons): 8.0 parts

[0269] Ester compound A (dipentaerythritol hexasorbate, melting point 87°C): 8.0 parts

[0270] • Ester compound B (ethylene glycol distearate): 12.0 parts

[0271] The above materials were premixed using an FM mixer (manufactured by Nippon Coke & Engineering Co., Ltd.), and then melt-blended using a twin-screw extruder (trade name: PCM-30, manufactured by Ikegai Corporation) to obtain a compound. The obtained compound was cooled, coarsely pulverized using a hammer mill (manufactured by Hosokawa Micron Corporation), and then further pulverized using a mechanical pulverizer (trade name: T-250, manufactured by Turbo Kogyo Co., Ltd.) to obtain a fine powder. The fine powder was then classified using a multi-stage classifier utilizing the wall adhesion effect (trade name: EJ-L-3, manufactured by Nittetsu Mining Co., Ltd.) to obtain toner particles 19. The weight-average particle size (D4) of the toner particles 19 is 6.5 μm.

[0272] The average roundness of the toner particles 19 was measured using the method described above, and the result was that the average roundness of the toner particles 19 was 0.940.

[0273] <Example of the formation of toner particles 29>

[0274] The toner particles 29 are formed according to the embodiment in Japanese Patent Application Publication No. 2007-322477. Details are described below.

[0275] (1) Production of binder resins for colorants

[0276] A dispersion was prepared by adding 100 parts of a monomer component, consisting of 84.3 parts styrene, 14.9 parts lauryl methacrylate, 0.5 parts 1,6-hexanediol diacrylate, 0.3 parts trimethylolpropane trimethacrylate, and 3 parts benzoyl peroxide as a polymerization initiator, to a liquid containing 0.2 parts polyvinyl alcohol (PVA235 manufactured by Kuraray Co., Ltd.) as a dispersant, to 200 parts deionized water. Fischer-Tropsch wax was added to this dispersion to make it 9.9 parts relative to the vinyl copolymer formed by the copolymerization of the 100 parts monomer component; and the mixture was subjected to suspension polymerization at 125°C for 4 hours, followed by cooling. For reference, prior to cooling, a 25% aqueous sodium hydroxide solution, making up 2% of the dispersion volume, was added to adjust the pH of the dispersion to above 5.5, thereby neutralizing residual benzoic acid as a polymerization initiator. Subsequently, the resin particles are separated by filtration, and a binder resin for colorant is obtained.

[0277] (2) Production of colorant granules

[0278] 95 parts of the toner obtained were mixed with binder resin using a small pulverizer, along with 5 parts of colorant (trade name: Carbon Black MA-100, manufactured by Mitsubishi Chemical Corporation) and 1 part of charge control agent (trade name: BONTRONS-34, manufactured by Orient Chemical Industries Co., Ltd.). The mixture was then kneaded at 90°C for 10 minutes using a Labo Plastomill (manufactured by Toyo Seiki Seisaku-sho, Ltd., 100 ml capacity, 70 rpm). The mixture was then cooled to room temperature, pulverized using a laboratory jet mill (manufactured by Nippon Pneumatic Mfg. Co., Ltd.), and classified using an air classifier (manufactured by Nippon Pneumatic Mfg. Co., Ltd.). A toner with a weight-average particle size (D4) of 8.0 μm was obtained.

[0279] The average roundness of the toner particles 29 was measured using the above method, and the result was that the average roundness of the toner particles 29 was 0.940.

[0280] <Example of Toner Production>

[0281] <Production of Toner 1>

[0282] • Toner granules 1,100 parts

[0283] 1.5 parts hydrophobic silica

[0284] • Hydrotalcite (trade name: DHT-4A: manufactured by Kyowa Chemical Industry Co., Ltd.) 0.3 parts

[0285] The above materials were mixed and stirred at 3000 rpm for 10 minutes using an FM mixer (manufactured by Nippon Coke & Engineering Co., Ltd.). The mixture was passed through a 200-mesh sieve to obtain toner 1. The obtained toner was analyzed according to <Method for separating binder resin and ester compounds from toner>, <Measuring the molecular weight of ester compounds by mass spectrometry>, <Method for measuring the content of ester compounds in toner>, <Compositional analysis of binder resin>, and <Method for measuring the average roundness of toner and toner particles>. As a result, the ratio of the unit represented by formula (1), ester compound A, and ester compound B in the toner was the same as the ratio of the input components.

[0286] The physical properties of toner 1 are shown in Table 5.

[0287] Production of Toners 2 to 15, Toner 18, and Toners 21 to 24

[0288] Except that in the production example of toner 1, toner particles 1 are changed to toner particles 2 to 15, toner particles 18, and toner particles 20 to 23, toners 2 to 15, 18, and 21 to 24 are obtained in the same manner as in the production example of toner 1. The obtained toners are prepared according to <Method for separating binder resin and ester compound from toner>, <Measuring the molecular weight of ester compound by mass spectrometry>, <Method for measuring the content of ester compound in toner>, <Compositional analysis of binder resin>, and <Method for measuring the average roundness of toner and toner particles>. As a result, the ratio of the unit represented by formula (1), ester compound A, and ester compound B in the toner is the same as the ratio of the input components.

[0289] The physical properties of toners 2 to 15, toner 18 and toners 21 to 24 are shown in Table 5.

[0290] <Production of Toner 19>

[0291] • Toner granules 2,100 parts

[0292] 1.5 parts hydrophobic silica

[0293] The above materials were mixed and stirred at 3000 rpm for 10 minutes using an FM mixer (manufactured by Nippon Coke & Engineering Co., Ltd.). The mixture was passed through a 200-mesh sieve to obtain toner 19. The obtained toner was analyzed according to <Method for separating binder resin and ester compounds from toner>, <Measuring the molecular weight of ester compounds by mass spectrometry>, <Method for measuring the content of ester compounds in toner>, <Compositional analysis of binder resin>, and <Method for measuring the average roundness of toner and toner particles>. As a result, the ratio of the unit represented by formula (1), ester compound A, and ester compound B in the toner was the same as the ratio of the input components.

[0294] The physical properties of toner 19 are shown in Table 5.

[0295] <Production of Toner 20, Toners 25 to 27, and Toner 30>

[0296] Except for changing the toner particles 2 to toner particles 19, 24 to 26, and 29 in the production example of toner 19, toner particles 20, 25 to 27, and 30 were obtained in the same manner as in the production example of toner 19. The obtained toners were analyzed according to <Method for separating binder resin and ester compounds from toner>, <Measuring the molecular weight of ester compounds by mass spectrometry>, <Method for measuring the content of ester compounds in toner>, <Compositional analysis of binder resin>, and <Method for measuring the average roundness of toner and toner particles>. As a result, the ratio of the unit represented by formula (1), ester compound A, and ester compound B in the toner was the same as the ratio of the input components.

[0297] The physical properties of toners 20, 25 to 27 and 30 are shown in Table 5.

[0298] [Table 5]

[0299] In Table 5, under the category of adhesive resin, "Y" indicates that the adhesive resin contains a unit represented by formula (1), and "N" indicates that the adhesive resin does not contain a unit represented by formula (1). Additionally, under the categories of ester compound A and ester compound B, "Formula (2)" through "Formula (6)" indicate compounds represented by formulas (2) through (6); and "Y" indicates that the toner particles contain compounds represented by formulas (2) through (6), and "N" indicates that the toner particles do not contain compounds represented by formulas (2) through (6). "Ratio of Formula (1)" indicates the ratio of the mass of the unit represented by formula (1) to the mass of the adhesive resin. Under the category of hydrotalcite, "Y" indicates that the toner contains hydrotalcite as an external additive, and "N" indicates that the toner does not contain hydrotalcite.

[0300] [Examples and Comparative Examples]

[0301] Evaluations were conducted using toners 1 to 15, 18 to 27, and 30 in combinations shown in Table 6. The evaluation results are shown in Table 6.

[0302] The evaluation methods and evaluation criteria of this disclosure will be described below.

[0303] As an image forming apparatus, a modified machine using a commercially available laser printer LBP-712Ci (manufactured by Canon Inc.) with a processing speed set to 300 mm / s and variable temperature control of the fuser unit was used, along with a commercially available toner cartridge 040H (black) (manufactured by Canon Inc.) as the processing cartridge. Product toner was removed from the cartridge, the interior was cleaned by blowing air, and then 165 g of the disclosed toner was refilled. For reference, yellow, magenta, and cyan cartridges, respectively, with product toner removed and the toner remaining quantity detection mechanism disabled, were inserted into the yellow, magenta, and cyan stations, respectively; and evaluation was performed.

[0304] Image gloss was evaluated under normal temperature and humidity conditions (temperature 25.0℃ and relative humidity 50%).

[0305] The temperature of the fixing device is controlled in 5°C increments within a range of 160°C to 280°C. The 150g gloss paper used is BROCHURE PAPER (manufactured by Hewlett Packard Enterprise: 150g / m²). 2 The medium is used to output 50 solid black images with a 100% print rate. Image gloss is measured at five points: the top left, top right, center, bottom left, and bottom right of the first image. The average image gloss at which the average gloss at these five points reaches its highest value within a given temperature range is defined as the image gloss. The temperature at which the average gloss at the five points reaches its highest value is defined as the fixing temperature. The standard deviation of the image gloss at the five points is used as an indicator of image gloss uniformity. The evaluation criteria are as follows.

[0306] <Evaluation of Image Glossiness>

[0307] A: The image gloss level is 70 or higher.

[0308] B: Image gloss level is 60 or higher but lower than 70.

[0309] C: Image gloss level is 50 or higher but lower than 60.

[0310] D: Image glossiness is below 50.

[0311] <Evaluation of Low-Temperature Fixing Performance>

[0312] A: The fixing temperature is below 190℃.

[0313] B: Fixing temperature exceeds 190℃ but is below 200℃.

[0314] C: Fixing temperature exceeds 200℃ but is below 210℃.

[0315] D: Fixing temperature exceeds 210℃.

[0316] <Evaluation of Image Gloss Uniformity>

[0317] A: The standard deviation of image gloss is below 1.5.

[0318] B: The standard deviation of image glossiness exceeds 1.5 but is below 3.0.

[0319] C: The standard deviation of image glossiness is greater than 3.0 and less than 4.5.

[0320] D: The standard deviation of image gloss exceeds 4.5.

[0321] Additionally, it was checked whether the image obtained at the fixing temperature up to the 50th frame was pasted onto the previous image, and the result was used as an indicator of image loadability. The evaluation criteria are shown below.

[0322] <Evaluation of Image Carrying Capacity>

[0323] A: No image pasting was observed.

[0324] B: Slight sticking was observed between the first and tenth sheets.

[0325] C: Slight sticking was observed between the 10th and 20th images.

[0326] D: Slight pasting was observed after the 20th image.

[0327] Furthermore, in images obtained at temperatures between the fixing temperature and a temperature 10°C higher, the offset from the back end of the image to the non-image portion is examined, and this offset is used as an indicator of demolding performance. The evaluation criteria are shown below.

[0328] <Evaluation of release properties>

[0329] A: No offset was observed.

[0330] B: A slight shift was observed in images obtained at a fixing temperature 10°C higher than the fixing temperature.

[0331] C: A slight shift was observed in images obtained at a fixing temperature 5°C higher than the fixing temperature.

[0332] D: A slight shift was observed in the image obtained at the fixing temperature.

[0333] The image with the glossiness of the image checked was stored for 30 days in a low-temperature and low-humidity environment (15°C / 10% RH), and the stored image was observed by an optical microscope and visual inspection, and the results were used as an index for the image storage stability. The evaluation criteria are shown below.

[0334] <Evaluation of Image Storage Stability>

[0335] A: No change was observed in the image.

[0336] B: Slight cracks were observed with an optical microscope, but not visually detectable.

[0337] C: Cracks were observed with an optical microscope, but not visually detectable.

[0338] D: Cracks were visually identified.

[0339] [Table 6]

[0340]

[0341] According to the present disclosure, a toner capable of achieving both high image glossiness and image bearing property can be provided. Although the present disclosure has been described with reference to exemplary embodiments, it should be understood that the present invention is not limited to the disclosed exemplary embodiments. The scope of the appended claims should be construed in the broadest manner to cover all such modifications as well as equivalent structures and functions.

Claims

1. A toner comprising toner particles and external additives, wherein the toner particles comprise: Styrene-acrylic resin having units represented by the following formula (1); And ester compound A, The external additive contains hydrotalcite. The ester compound A is an ester compound represented by formula (2) or formula (3): and SPb(J / cm 3 ) 1 / 2 and SPw1 (J / cm 3 ) 1 / 2 The absolute value of the difference is greater than or equal to 1.00 and less than or equal to 2.00, wherein SPb (J / cm 3 ) 1 / 2 The SP value of the styrene-acrylic resin is defined as SPw1 (J / cm). 3 ) 1 / 2 The SP value of the ester compound A is given. Where R 1 Represents a hydrogen atom or a methyl group, and R 2 It represents straight-chain alkyl groups with 10 to 14 carbon atoms, and Where R 11 To R 14 and R 21 To R 26 Each of these can be used independently to represent a straight-chain alkyl group having 15 to 21 carbon atoms.

2. The colorant according to claim 1, wherein the styrene-acrylic resin comprises units represented by formula (1) in an amount of 1 to 15% by mass based on the total mass of the styrene-acrylic resin.

3. The toner according to claim 1, wherein... The toner particles comprise ester compound B, wherein The ester compound B is an ester compound represented by formula (4), formula (5), or formula (6); and The SPb (J / cm 3 ) 1 / 2 and SPw2 (J / cm 3 ) 1 / 2 The absolute value of the difference is less than 2.10, and the SPw2 (J / cm) 3 ) 1 / 2 The SP value of the ester compound B is given. Where R 31 and R 41 Each independently represents an alkylene group having 2 to 8 carbon atoms, and R 32 R 33 R 42 R 43 R 51 and R 52 Each can be used independently to represent a straight-chain alkyl group having 14 to 24 carbon atoms.

4. The toner according to claim 1, wherein... The ester compound A is an ester compound represented by the following formula (2') or the following formula (3'): Where R 11 To R 14 and R 21 To R 26 Each of these can be used independently to represent a straight-chain alkyl group having 17 to 21 carbon atoms.

5. The toner according to claim 4, wherein the ester compound A is an ester compound represented by formula (2').

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