Toner

Abstract

The invention relates to a toner. The toner includes toner particles including a resin component. Toner particles contain, as a resin component, a crystalline vinyl resin having a unit (a) represented by formula (1). The resin component contains the unit (a) in an amount of from 15.0% by mass to 40.0% by mass (inclusive) based on the mass of the resin component. The content of the unit (a) in a component separated by gradient LC analysis of an acetonitrile / chloroform eluted component of a chloroform-soluble substance W of the toner particle has a specific relationship with a storage elastic modulus at 100 DEG C.

Description

Technical Field

[0001] The present disclosure relates to toners. Background Art

[0002] In the field of electrophotographic apparatuses, energy saving is regarded as a major technical issue, and significant reduction of heat related to a fixing device has been studied. For toners, there is an increasing need for so-called "low-temperature fixability" that enables fixing at low energy.

[0003] As a method capable of fixing at low temperature, International Publication No. 2013 / 047296 discloses a toner containing a plasticizer. The plasticizer increases the softening rate of the binder resin while maintaining the glass transition temperature (Tg) of the toner, and can improve the low-temperature fixability. However, since the toner softens through a process in which the binder resin is plasticized after the plasticizer melts, there is a limit to the melting rate of the toner, and thus further improvement of the low-temperature fixability is desired.

[0004] Therefore, a method of using a crystalline resin as the binder resin has been studied. An amorphous resin commonly used as a binder resin for toners does not exhibit a distinct endothermic peak in differential scanning calorimetry (DSC), but when the toner contains a crystalline resin component, an endothermic peak (melting point) appears in DSC.

[0005] A crystalline resin in which molecular chains are regularly arranged has a property of hardly softening at a temperature lower than its melting point. On the other hand, at a temperature higher than its melting point, the crystal rapidly melts, accompanied by a rapid decrease in viscosity. A crystalline resin having such excellent rapid melting property has attracted attention as a useful material for improving the low-temperature fixability of toners.

[0006] In some toners, a crystalline vinyl resin having a long-chain alkyl group as a side chain in its molecule is used as the crystalline resin. Generally, a crystalline vinyl resin has a structure in which a long-chain alkyl group as a side chain is bonded to the main chain, and the crystallization of the long-chain alkyl group as a side chain causes the crystalline vinyl resin to function as a crystalline resin.

[0007] Japanese Patent Laid-Open No. 2022-162968 discloses, as a toner using a crystalline vinyl resin, a toner using a crystalline vinyl resin obtained by copolymerizing a polymerizable monomer having a long-chain alkyl group with an amorphous polymerizable monomer having a different SP value.

[0008] However, the disadvantage of crystalline vinyl resins is that at high temperatures, their viscosity tends to decrease, making them prone to thermal fouling. To overcome this disadvantage, Japanese Patent Laid-Open No. 2021-096463 discloses a toner in which a domain-matrix structure including a non-crystalline resin in addition to the crystalline vinyl resin is formed.

[0009] However, as a result, toners that combine crystalline vinyl resins and non-crystalline resins tend to experience a decrease in gloss during fixing. During fixing, the crystalline vinyl resin becomes molten and undergoes a rapid decrease in viscosity. In contrast, the non-crystalline resin is not in a molten state, or even if molten, its viscosity decreases slowly, resulting in the formation of regions with relatively high viscosity and regions with relatively low viscosity inside the toner. As a result, thermal fouling is likely to occur, and minute irregularities are formed on the surface of the fixed image, leading to a decrease in gloss. It has been found that this phenomenon occurs significantly in low-temperature fixing and high-speed printing systems where the molten states of the resins tend to be different from each other.

[0010] The present disclosure aims to provide a toner excellent in low-temperature fixability and heat-resistant fouling property. Summary of the Invention

[0011] The present disclosure provides a toner including toner particles containing a resin component, wherein the resin component contains a crystalline vinyl resin having a unit (a) represented by formula (1).

[0012]

[0013] In the above formula (1), R 1represents a hydrogen atom or a methyl group, n represents an integer of 15 to 35, the resin component contains unit (a) in an amount of 15.0% by mass or more and 40.0% by mass or less based on the mass of the resin component. When the toner particles are subjected to Soxhlet extraction with chloroform for 18 hours to obtain chloroform-soluble substances, and the components with a molecular weight of 2,000 or less are removed from them by recycling HPLC to obtain chloroform-soluble substance W, for chloroform-soluble substance W, when acetonitrile is used as the poor solvent and chloroform is used as the good solvent, and at the same time the mobile phase is linearly changed from 100% by volume of acetonitrile to 100% by volume of chloroform, and gradient LC analysis is performed on the eluted components, in the graph where the horizontal axis represents the percentage of chloroform (volume%) in the mobile phase and the vertical axis represents the signal intensity (μA) of the eluted components detected by a charged particle detector, there are multiple local maximal values. When among the multiple local maximal values, the local maximal value with a smaller percentage of chloroform in the mobile phase between the local maximal value with the largest intensity and the local maximal value with the second largest intensity is local maximal value PA, and the local maximal value with a larger percentage of chloroform in the mobile phase is local maximal value PB, and the local minimum value with the smallest intensity existing between local maximal value PA and local maximal value PB is local minimum value BAB, and the percentage of chloroform at local minimum value BAB is VAB volume% (20.0 < VAB < 95.0), the component with a percentage of chloroform in the mobile phase of 20.0% by volume or more and less than VAB volume% is component A, and the component with a percentage of chloroform in the mobile phase of VAB volume% or more and 95.0% by volume or less is component B, the resin component contains component B in an amount of 40.0% by mass or more and 80.0% by mass or less based on the mass of the resin component. When the content of unit (a) in chloroform-soluble substance W is WC mass%, and the content of unit (a) in component B is WB mass%, WC and WB satisfy formula (2),

[0014] WB / WC ≥ 0.70 (2), and

[0015] When the storage elastic modulus of the toner particles at 100 °C is G'(T), and the storage elastic modulus of component B at 100 °C is G'(B), G'(T) and G'(B) satisfy formula (3) and formula (4).

[0016] 5.0 × 10 3 Pa ≤ G'(T) ≤ 1.0 × 10 5 Pa (3)

[0017] 2.0 × 10 3 Pa ≤ G'(T) - G'(B) ≤ 6.0 × 10 3 Pa (4).

[0018] The further features of the present invention will become apparent from the following description of exemplary embodiments. Detailed Description

[0019] In the present disclosure, unless otherwise specified, the phrases "XX or more and YY or less" and "XX to YY" indicating a numerical range each refer to a numerical range including its endpoints, i.e., the lower limit and the upper limit. When describing a numerical range in a stepwise manner, the upper limit of each numerical range can be combined with the lower limit of any other numerical range.

[0020] The term "(meth)acrylate" means acrylate and / or methacrylate.

[0021] The term "monomer unit" refers to the reaction form of a monomer substance in a polymer. For example, in a polymer, one carbon-carbon bond portion in the main chain formed by the polymerization of a polymerizable monomer is one unit. The polymerizable monomer can be represented by, for example, the following formula (C).

[0022]

[0023] In the above formula (C), R A represents a hydrogen atom or an alkyl group (preferably an alkyl group having 1 to 3 carbon atoms, more preferably a methyl group), and R B represents a monovalent group.

[0024] The term "crystalline resin" refers to a resin that exhibits a distinct endothermic peak in differential scanning calorimetry (DSC).

[0025] The present inventors have found that the above disadvantages can be solved by appropriately controlling the viscoelasticity of the resin component in the toner particles containing a large amount of crystalline vinyl resin and the viscoelasticity of the toner particles (the entire toner particles).

[0026] The toner according to the present disclosure is a toner including toner particles, and the toner particles contain a resin component.

[0027] wherein the toner particles contain a crystalline vinyl resin having a unit (a) represented by the following formula (1) as the resin component.

[0028]

[0029] In the above formula (1), R 1 represents a hydrogen atom or a methyl group, n represents an integer of 15 to 35, and the resin component contains unit (a) in an amount of 15.0% by mass or more and 40.0% by mass or less based on the mass of the resin component.

[0030] When the toner particles are subjected to Soxhlet extraction with chloroform for 18 hours to obtain chloroform-soluble substances, and the components having a molecular weight of 2,000 or less are removed therefrom by recycling HPLC to obtain chloroform-soluble substances W,

[0031] For the chloroform-soluble substances W, when acetonitrile is used as a poor solvent and chloroform is used as a good solvent, and the mobile phase is linearly changed from 100% by volume of acetonitrile to 100% by volume of chloroform, and gradient LC analysis is performed on the eluted components,

[0032] In a graph in which the horizontal axis represents the percentage of chloroform (volume%) in the mobile phase and the vertical axis represents the signal intensity (μA) of the eluted components detected using an electrified particle detector, there are a plurality of maxima,

[0033] When, among the maxima having the largest intensity and the second largest intensity among the plurality of maxima, the maximum having a smaller percentage of chloroform in the mobile phase is maximum PA, and

[0034] the maximum having a larger percentage of chloroform in the mobile phase is maximum PB, and the minimum having the smallest intensity existing between maximum PA and maximum PB is minimum BAB,

[0035] The percentage of chloroform at minimum BAB is VAB volume% (20.0 < VAB < 95.0),

[0036] The components having a percentage of chloroform in the mobile phase of 20.0% by volume or more and less than VAB volume% are components A, and

[0037] when the components having a percentage of chloroform in the mobile phase of VAB volume% or more and 95.0% by volume or less are components B,

[0038] The resin component contains component B in an amount of 40.0% by mass or more and 80.0% by mass or less based on the mass of the resin component,

[0039] When the content of unit (a) in the chloroform-soluble substances W is WC mass%, and

[0040] the content of unit (a) in component B is WB mass%,

[0041] WC and WB satisfy the following formula (2),

[0042] WB / WC ≥ 0.70 (2), and

[0043] When the storage elastic modulus of the toner particles at 100°C is G'(T), and

[0044] the storage elastic modulus of component B at 100°C is G'(B),

[0045] G'(T) and G'(B) satisfy the following formulas (3) and (4),

[0046] 5.0 × 10 3 Pa ≤ G'(T) ≤ 1.0 × 10 5 Pa (3)

[0047] 2.0 × 10 3 Pa ≤ G'(T) - G'(B) ≤ 6.0 × 10 3 Pa (4).

[0048] The toner according to the present disclosure is a toner including toner particles, and the toner particles include a resin component. The toner particles include a crystalline vinyl resin having a unit (a) represented by the following formula (1) as the resin component.

[0049]

[0050] In the above formula (1), R 1 represents a hydrogen atom or a methyl group, and n represents an integer of 15 to 35.

[0051] Unit (a) represents a unit having a long-chain alkyl group. Due to the presence of unit (a), the resin component acts as a crystalline vinyl resin. When n in the above formula (1) is 15 to 35, the crystallinity of the crystalline vinyl resin is likely to be exhibited. n is preferably an integer of 17 to 29.

[0052] The resin component according to the present disclosure includes unit (a) in an amount of 15.0% by mass or more and 40.0% by mass or less based on the mass of the resin component. When the amount of unit (a) is within this range, the amount of crystals in the toner is appropriate and provides good low-temperature fixability. When the amount of unit (a) is less than 15.0% by mass, the amount of crystals in the toner is small, resulting in low low-temperature fixability. When the amount of unit (a) is greater than 40.0% by mass, the amount of crystals in the toner (toner particles) is too large, and the melt viscosity of the toner during fixing is too low, resulting in low heat stain resistance. The preferred range of unit (a) in the resin component is 20.0% by mass or more and 35.0% by mass or less.

[0053] Gradient LC analysis will be described. Unless otherwise specified, gradient LC analysis is performed as follows.

[0054] The toner particles were subjected to Soxhlet extraction with chloroform solvent for 18 hours to obtain soluble substances, and the components with a molecular weight of 2,000 or less were removed therefrom by recycling HPLC to obtain chloroform-soluble substance W, which was used as a sample. For the chloroform-soluble substance extracted from the toner particles, acetonitrile was used as a poor solvent and chloroform was used as a good solvent, and at the same time, the mobile phase was linearly changed from 100% by volume of acetonitrile to 100% by volume of chloroform.

[0055] Gradient LC analysis was performed on the eluted components obtained during this change.

[0056] As a result, a graph was obtained in which the horizontal axis represents the percentage of chloroform (volume %) in the mobile phase and the vertical axis represents the signal intensity (μA) of the eluted components detected using an electrified particle detector. Acetonitrile is a solvent with high polarity, and the components with high polarity are eluted first. As the percentage of chloroform increases, the components with low polarity are gradually eluted. Therefore, in this analysis, separation can be performed according to the polarity in the chloroform-soluble substance W. The toner according to the present disclosure exhibits multiple maxima in this analysis. Among the maxima with the largest intensity and the second largest intensity among the multiple maxima, the maximum with a relatively small percentage of chloroform in the mobile phase, that is, the maximum with a relatively high polarity here, is maximum PA. The maximum with a relatively large percentage of chloroform in the mobile phase, that is, the maximum with a relatively low polarity here, is maximum PB. The minimum with the smallest intensity existing between maximum PA and maximum PB is minimum BAB, and the percentage of chloroform at minimum BAB is VAB volume % (20.0 < VAB < 95.0). The components with a chloroform percentage in the mobile phase of 20.0% by volume or more and less than VAB volume % are component A, and the components with a chloroform percentage in the mobile phase of VAB volume % or more and 95.0% by volume or less are component B.

[0057] The resin component according to the present disclosure contains component B in an amount of 40.0% by mass or more and 80.0% by mass or less based on the mass of the resin component. When the content of unit (a) in the chloroform-soluble substance W is WC mass %, and the content of unit (a) in component B is WB mass %, WC and WB satisfy the following formula (2).

[0058] WB / WC ≥ 0.70 (2)

[0059] Unit (a) has relatively low polarity due to having a long-chain alkyl group. Therefore, satisfying the above formula (2) means that component A and component B are clearly separated from each other, and most of the crystalline vinyl resin, that is, unit (a) exhibiting crystallinity, exists in component B.

[0060] Containing component B in an amount of 40.0 mass% or more and 80.0 mass% or less based on the mass of the resin component means that the component having crystallinity is present in an appropriate amount, thereby providing good low-temperature fixability. When the amount of component B is less than 40.0 mass%, the amount of the component exhibiting crystallinity is too small, resulting in poor low-temperature fixability. When the amount of component B exceeds 80.0 mass%, the amount of the component exhibiting crystallinity is too large, resulting in low heat stain resistance. The preferred range of component B in the resin component is 50.0 mass% or more and 75.0 mass% or less, more preferably 55.0 mass% or more and 70.0 mass% or less. The content of component B in the resin component can be controlled by the content of the crystalline vinyl resin in the resin component, the content of unit (a) in the crystalline vinyl resin, etc.

[0061] In the toner according to the present disclosure, when the storage modulus of elasticity at 100 °C of the toner particles is G'(T), G'(T) satisfies the following formula (3).

[0062] 5.0 × 10 3 Pa ≤ G'(T) ≤ 1.0 × 10 5 Pa (3)

[0063] The storage modulus of elasticity at 100 °C represents the viscosity of the toner particles after melting. When G'(T) is within the above range, the penetration of the toner particles into the paper and the peeling from the fixing film can be effectively achieved, and good low-temperature fixability can be provided. When G'(T) is less than 5.0×10 3 Pa, the viscosity of the toner particles after melting is too low, so that the toner is likely to migrate to the fixing member (such as the fixing film) during fixing, resulting in low heat stain resistance. When G'(T) is greater than 1.0×10 5 Pa, the viscosity of the toner particles after melting is too high, so that the penetration of the toner particles into the paper is not likely to occur during fixing, resulting in poor low-temperature fixability. The preferred range of G'(T) is 8.0×10 3 Pa or more and 8.0×10 4 Pa or less, more preferably 9.0×10 3 Pa or more and 5.0×10 4 Pa or less. G'(T) can be controlled by the content of unit (a) in the resin component in the toner particles, the molecular weight of the resin component, the content of component B, etc.

[0064] In the toner particles according to the present disclosure, when the storage modulus of elasticity at 100 °C of component B is G'(B), the following formula (4) is satisfied.

[0065] 2.0 × 10 3Pa ≤ G'(T) - G'(B) ≤ 6.0 × 10 3 Pa (4)

[0066] As described above, most of the unit (a) showing crystallinity in the resin component is present in component B. Therefore, the storage elastic modulus of component B at 100°C is relatively low compared to the storage elastic modulus of toner particles at 100°C. On the other hand, if a component having a significantly different storage elastic modulus at 100°C is present in the toner particles, a region having a relatively high viscosity and a region having a relatively low viscosity are formed inside the toner particles at the time of fixing, so that minute concavoconvexities are formed on the surface of the fixed image, thereby causing a decrease in glossiness. This phenomenon significantly occurs in low-temperature fixing and high-speed printing systems in which the melting states of the resins tend to be different from each other.

[0067] When the above formula (4) is satisfied, the relative difference in storage elastic modulus is within an appropriate range, and thus high gloss can be achieved even at high-speed and low-temperature fixing.

[0068] When G'(T)-G'(B) is less than 2.0×10 3 Pa, penetration into paper is less likely to occur during fixing, resulting in a fixed image with low scratch resistance. 3 When the glossiness is less than 0.05 Pa, the glossiness is low during high-speed and low-temperature fixing.

[0069] G'(T)-G'(B) can be controlled by the content of the crystalline vinyl resin occupying most of component B, the ratio of the unit (a) in the crystalline vinyl resin, the molecular weight of the crystalline vinyl resin, and the like.

[0070] Component B according to the present disclosure will be described.

[0071] In component B, most of the crystalline vinyl resin is present as described above.

[0072] Component B may contain unit (a) in an amount of 25.0% by mass or more and 50.0% by mass or less based on the mass of component B. Within this range, the content of unit (a) in the toner particles tends to be in an appropriate range, and low temperature fixability and hot offset resistance tend to be well balanced. The amount of unit (a) is preferably 30.0% by mass or more and 45.0% by mass or less.

[0073] In Component B, the weight-average molecular weight (Mw) of the tetrahydrofuran (THF)-soluble matter measured by gel permeation chromatography (GPC) is preferably 30,000 or more and 200,000 or less. When Mw is within this range, G'(T) - G'(B) tends to be within an appropriate range. The preferred range of Mw is 40,000 or more and 180,000 or less, more preferably 60,000 or more and 150,000 or less.

[0074] A crystalline vinyl resin according to the present disclosure will be described.

[0075] The crystalline vinyl resin is a component that mostly exists in Component B as described above.

[0076] The crystalline vinyl resin contains Unit (a), and an example of a method for introducing Unit (a) is to polymerize the (meth)acrylates listed below. Examples include (meth)acrylic acid comparison esters, (meth)acrylic acid nonadecyl esters, (meth)acrylic acid eicosyl esters, (meth)acrylic acid heneicosyl esters, (meth)acrylic acid behenyl esters, (meth)acrylic acid tetracosyl esters, (meth)acrylic acid hexacosyl esters, (meth)acrylic acid dico comparison esters, (meth)acrylic acid triacontyl esters, (meth)acrylic acid dotriacontyl esters, and (meth)acrylic acid 2-decyltetradecyl esters.

[0077] The Unit (a) contained in the crystalline vinyl resin may be a single type or two or more types.

[0078] The content percentage of Unit (a) in the crystalline vinyl resin is preferably 40.0% by mass or more and 90.0% by mass or less, more preferably 45.0% by mass or more and 85.0% by mass or less, still more preferably 50.0% by mass or more and 80.0% by mass or less. Within this range, a better balance between low-temperature fixability and heat stain resistance is provided.

[0079] The crystalline vinyl resin may have other units in addition to Unit (a). An example of a method for introducing other units into the crystalline vinyl resin is to polymerize any of the above (meth)acrylates with other vinyl monomers.

[0080] Examples of other vinyl monomers include the following:

[0081] Styrene, α-methylstyrene, and (meth)acrylate esters such as (meth)acrylic acid methyl ester, (meth)acrylic acid ethyl ester, (meth)acrylic acid n-butyl ester, (meth)acrylic acid tert-butyl ester, and (meth)acrylic acid 2-ethylhexyl ester;

[0082] Monomers having a urea group, for example, monomers obtained by reacting an amine having 3 to 22 carbon atoms [such as primary amines (e.g., n-butylamine, tert-butylamine, propylamine, and isopropylamine), secondary amines (e.g., di-n-ethylamine, di-n-propylamine, and di-n-butylamine), aniline, and cyclohexylamine] with an isocyanate having an ethylenically unsaturated bond and having 2 to 30 carbon atoms by means of a known method;

[0083] Monomers having a carboxyl group, such as methacrylic acid, acrylic acid, and 2-carboxyethyl (meth)acrylate;

[0084] Monomers having a hydroxyl group, such as 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate;

[0085] Monomers having an amide group, such as acrylamide and monomers obtained by reacting an amine having 1 to 30 carbon atoms with a carboxylic acid having an ethylenically unsaturated bond and having 2 to 30 carbon atoms (such as acrylic acid and methacrylic acid) by means of a known method; and

[0086] Monomers having a lactam structure, such as N-vinyl-2-pyrrolidone.

[0087] Among them, monomers having a lactam structure are preferred, a lactam structure having a five-membered ring is more preferred, and N-vinyl-2-pyrrolidone is even more preferred. The percentage of units having a lactam structure contributes to improving the affinity between the crystalline vinyl resin and the paper, thereby providing a fixed image having improved rub resistance.

[0088] The content percentage of units having a lactam structure in the crystalline vinyl resin is preferably 2.0% by mass or more and 15.0% by mass or less.

[0089] The crystalline vinyl resin can also be synthesized by copolymerizing a (meth)acrylate for introducing unit (a) with other vinyl-based monomers to obtain a crystalline vinyl resin, and then further reacting other vinyl-based monomers by a hydrogen abstraction reaction. The hydrogen abstraction reaction is a reaction in which a hydrogen atom bonded to a carbon atom is abstracted to generate a radical, and the other vinyl-based monomers can further react with the generated radical. This enables the formation of a state in which unit (a) in the crystalline vinyl resin is more aggregated in the molecule and contributes to improving crystallinity. This also helps to satisfy the above formula (4).

[0090] In the crystalline vinyl resin, the weight average molecular weight (Mw) of the tetrahydrofuran (THF) soluble matter measured by gel permeation chromatography (GPC) is preferably 30,000 or more and 200,000 or less. When Mw is within this range, G'(T) - G'(B) tends to be within an appropriate range. The preferred range of Mw is 40,000 or more and 180,000 or less, more preferably 60,000 or more and 150,000 or less.

[0091] Regarding the content of the crystalline vinyl resin in the toner particles according to the present disclosure, based on the mass of the toner particles, it is preferably 30.0% by mass or more and 80.0% by mass or less. Within this range, the crystalline components in the toner particles tend to be present in an appropriate amount, and low-temperature fixability and heat-resistant stain resistance tend to be achieved simultaneously. The content of the crystalline vinyl resin is more preferably 40.0% by mass or more and 75.0% by mass or less, still more preferably 50.0% by mass or more and 70.0% by mass or less.

[0092] In the toner particles according to the present disclosure, in differential scanning calorimetry (DSC), the melting point derived from the crystalline vinyl resin is preferably 50°C or more and 80°C or less. When the melting point derived from the crystalline vinyl resin is within this range, low-temperature fixability tends to be improved. The preferred range of the melting point is 55°C or more and 75°C or less, and the more preferred range is 57°C or more and 70°C or less.

[0093] Component A according to the present disclosure will be described.

[0094] Component A is a component with a higher polarity than component B, and most of the crystalline vinyl resin is present in component B; therefore, most of the other resin components are present in component A. Examples of the other resin components include non-crystalline resins.

[0095] The resin component may contain component A in an amount of 10.0% by mass or more and 60.0% by mass or less based on the mass of the resin component. Within this range, the crystalline components in the toner particles tend to be present in an appropriate amount, and low-temperature fixability and heat-resistant stain resistance tend to be achieved simultaneously. The amount of component A is more preferably 15.0% by mass or more and 55.0% by mass or less, still more preferably 20.0% by mass or more and 50.0% by mass or less.

[0096] In component A, the weight average molecular weight (Mw) of the tetrahydrofuran (THF) soluble matter measured by gel permeation chromatography (GPC) is preferably 20,000 or more and 200,000 or less, more preferably 25,000 or more and 150,000 or less.

[0097] The amorphous resin is, for example, a vinyl resin, a polyester resin, a polyurethane resin, or an epoxy resin, and may be a vinyl resin or a polyester resin.

[0098] When the amorphous resin is a vinyl resin, vinyl monomers that can be used for crystalline vinyl resins can be used. (Meth)acrylates for introducing unit (a) can also be used as long as the amorphous resin does not exhibit crystallinity.

[0099] So-called crosslinking agents in which each monomer has multiple vinyl groups can also be used. Examples of the crosslinking agents include the following: diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, 1,6 - hexanediol diacrylate, neopentyl glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, 2,2’-bis(4-(acryloyloxy diethoxy)phenyl)propane, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, 1,3 - butanediol dimethacrylate, 1,6 - hexanediol dimethacrylate, neopentyl glycol dimethacrylate, polypropylene glycol dimethacrylate, 2,2’-bis(4-(methacryloyloxy diethoxy)phenyl)propane, 2,2’-bis(4-(methacryloyloxypolyethoxy)phenyl)propane, trimethylolpropane trimethacrylate, pentaerythritol tetramethacrylate, divinylbenzene, divinylnaphthalene, divinyl ether, and 4,4’-divinylbiphenyl.

[0100] When the amorphous resin is a polyester resin, a polyester resin obtained by the reaction of a polycarboxylic acid having 2 or more carbon atoms with a polyol can be used.

[0101] Examples of the polycarboxylic acid include the following: dibasic acids such as succinic acid, adipic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, malonic acid, and dodecenyl succinic acid, and their acid anhydrides and lower alkyl esters; aliphatic unsaturated dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, and citraconic acid; and 1,2,4 - benzenetricarboxylic acid, 1,2,5 - benzenetricarboxylic acid, and their acid anhydrides and lower alkyl esters. These can be used alone or in combination of two or more.

[0102] Examples of the polyol include the following: alkylene diols (ethylene glycol, 1,2 - propylene glycol, and 1,3 - propylene glycol); alkylene ether diols (polyethylene glycol and polypropylene glycol); alicyclic diols (1,4 - cyclohexanedimethanol); bisphenols (bisphenol A); and adducts of alicyclic diols and alkylene oxides (ethylene oxide and propylene oxide). The alkyl moieties of the alkylene diols and alkylene ether diols may be linear or branched. Further examples include glycerol, trimethylolethane, trimethylolpropane, and pentaerythritol. These may be used alone or in combination of two or more.

[0103] For the purpose of adjusting the acid value or hydroxyl value, monocarboxylic acids such as acetic acid or benzoic acid or monohydric alcohols such as cyclohexanol or benzyl alcohol may also be used as needed.

[0104] As a method for producing the polyester resin, for example, the transesterification method and the direct polycondensation method may be used alone or in combination.

[0105] The resin component according to the present disclosure contains chloroform - insoluble matter, and the content of the chloroform - insoluble matter is preferably 3.0% by mass or more and 15.0% by mass or less based on the mass of the resin component. Within this range, the toner tends to effectively provide elasticity, and low - temperature fixability and heat - stain resistance tend to be achieved simultaneously.

[0106] The toner particles according to the present disclosure may have a core - shell structure, which includes a core particle containing a resin and a shell covering the core particle. From the viewpoint of charging stability, the resin forming the shell is preferably a vinyl resin or a polyester resin, more preferably an amorphous polyester resin. The shell does not have to cover the entire core, and the core may be partially exposed. As the vinyl resin and polyester resin constituting the shell, the vinyl resins and polyester resins usable in the above - mentioned component A and component B may be used.

[0107] The toner particles may contain wax. The wax is at least one selected from the group consisting of hydrocarbon waxes and ester waxes. Using hydrocarbon waxes and / or ester waxes helps to provide effective releasability.

[0108] Examples of the hydrocarbon waxes include the following:

[0109] Aliphatic hydrocarbon waxes, such as low - molecular - weight polyethylene, low - molecular - weight polypropylene, low - molecular - weight olefin copolymers, Fischer - Tropsch waxes, and waxes obtained by oxidation or acid addition of these waxes.

[0110] The ester wax is not particularly limited as long as it has at least one ester bond in one molecule, and may be a natural ester wax or a synthetic ester wax.

[0111] Examples of the ester waxes include the following:

[0112] Esters of monohydric alcohols and monocarboxylic acids, such as behenyl behenate, stearyl stearate, and palmitoyl palmitate;

[0113] Esters of dibasic carboxylic acids and monohydric alcohols, such as behenyl sebacate;

[0114] Esters of dihydric alcohols and monobasic carboxylic acids, such as ethylene glycol distearate and hexylene glycol dibehenate;

[0115] Esters of trihydric alcohols and monobasic carboxylic acids, such as glyceryl tribehenate;

[0116] Esters of tetrahydric alcohols and monobasic carboxylic acids, such as pentaerythritol tetrastearate and pentaerythritol tetrapalmitate;

[0117] Esters of hexahydric alcohols and monobasic carboxylic acids, such as dipentaerythritol hexastearate, dipentaerythritol hexapalmitate and dipentaerythritol hexabehenate;

[0118] Esters of polyhydric alcohols and monobasic carboxylic acids, such as polyglyceryl behenate; and

[0119] Natural ester waxes, such as carnauba wax and rice wax.

[0120] Among them, ester waxes that are preferably esters of alcohols with 4 or more and 8 or less carbon atoms and aliphatic monobasic carboxylic acids, or esters of carboxylic acids with 4 or more and 8 or less carbon atoms and aliphatic monohydric alcohols. The presence of such waxes reduces the compatibility with crystalline vinyl resins during fixing, making the releasability during low-temperature fixing tend to be improved, resulting in higher low-temperature fixability.

[0121] More preferably, esters of tetrahydric alcohols and monobasic carboxylic acids, such as pentaerythritol tetrastearate, pentaerythritol tetrapalmitate and pentaerythritol tetrabehenate; esters of hexahydric alcohols and monobasic carboxylic acids, such as dipentaerythritol hexastearate, dipentaerythritol hexapalmitate and dipentaerythritol hexabehenate; and esters of octahydric alcohols and monobasic carboxylic acids, such as tripentaerythritol octastearate, tripentaerythritol octapalmitate and tripentaerythritol octabehenate.

[0122] The content of wax in the toner particles is preferably 1.0% by mass or more and 30.0% by mass or less, more preferably 2.0% by mass or more and 25.0% by mass or less. When the content of wax in the toner particles is within this range, it is easier to provide releasability during fixing.

[0123] The melting point of the wax is preferably 60°C or more and 120°C or less. When the melting point of the wax is within this range, the wax is easily melted during fixing, so that it oozes out to the surface of the toner particles, making the wax easily volatilized. The melting point of the wax is more preferably 70°C or more and 100°C or less.

[0124] Toner particles may contain a colorant. Examples of colorants include known organic pigments, organic dyes, inorganic pigments, carbon black as a black colorant, and magnetic particles. Additionally, colorants conventionally used in toners may be used.

[0125] Examples of yellow colorants include the following: condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complex compounds, methylene compounds, and allylamide compounds. Among them, C.I. Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 109, 110, 111, 128, 129, 147, 155, 168, and 180 are suitable for use.

[0126] Examples of magenta colorants include the following: condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. Among them, C.I. Pigment Red 2, 3, 5, 6, 7, 23, 48:2, 48:3, 48:4, 57:1, 81:1, 122, 144, 146, 166, 169, 177, 184, 185, 202, 206, 220, 221, and 254 are suitable for use.

[0127] Examples of cyan colorants include the following: copper phthalocyanine compounds and their derivatives, anthraquinone compounds, and basic dye lake compounds, etc. Among them, C.I. Pigment Blue 1, 7, 15, 15:1, 15:2, 15:3, 15:4, 60, 62, and 66 are suitable for use.

[0128] Colorants are selected from the viewpoints of hue angle, color saturation, lightness value, lightfastness, OHP transparency, and dispersibility in the toner.

[0129] The content of the colorant in the toner particles is preferably 1.0 part by mass or more and 20.0 parts by mass or less with respect to 100.0 parts by mass of the toner particles. When magnetic particles are used as the colorant, its content is preferably 40.0 parts by mass or more and 150.0 parts by mass or less with respect to 100.0 parts by mass of the toner particles.

[0130] Toner particles may contain a charge control agent. Optionally, the charge control agent may be externally added to the toner particles. The use of the charge control agent stabilizes the charge characteristics and enables control of the optimum triboelectric charge amount according to the developing system.

[0131] The charge control agent may be a charge control agent having a high charging speed and capable of stably maintaining a constant charge amount.

[0132] Examples of charge control agents for controlling the toner to be negatively charged include the following. Organometallic compounds and chelates are effective, and examples include monoazo metal compounds, metal acetylacetonate compounds, and metal compounds of aromatic oxycarboxylic acid series, aromatic dicarboxylic acid series, hydroxycarboxylic acid series, and dicarboxylic acid series.

[0133] Examples of charge control agents for controlling the toner to be positively charged include the following: aniline black, quaternary ammonium salts, metal salts of higher fatty acids, diorganotin borates, guanidine compounds, and imidazole compounds.

[0134] The content of the charge control agent in the toner particles is preferably 0.01 part by mass or more and 20.0 parts by mass or less, more preferably 0.5 part by mass or more and 10.0 parts by mass or less, relative to 100.0 parts by mass of the toner particles.

[0135] The toner particles can be used as a toner without any treatment or with external additives or the like added as needed and attached to the surface of the toner particles.

[0136] Examples of the external additives include inorganic fine particles selected from the group consisting of fine silica particles, fine alumina particles, and fine titanium dioxide particles, and their composite oxides. Examples of the composite oxides include fine silica-alumina particles and fine strontium titanate particles.

[0137] The content of the external additives is preferably 0.01 part by mass or more and 8.0 parts by mass or less, more preferably 0.1 part by mass or more and 4.0 parts by mass or less, relative to 100 parts by mass of the toner particles.

[0138] The toner particles according to the present disclosure can be produced by any known method such as suspension polymerization method, emulsion aggregation method, dissolution suspension method, or pulverization method, and can be produced by the suspension polymerization method.

[0139] The suspension polymerization method will be described in detail.

[0140] For example, a pre-synthesized crystalline vinyl resin is added to a mixture of polymerizable monomers, and other materials such as a colorant, wax, and charge control agent are added as needed and uniformly dissolved or dispersed to prepare a polymerizable monomer composition.

[0141] Thereafter, the polymerizable monomer composition is dispersed in an aqueous medium using a stirrer or the like to prepare suspended particles of the polymerizable monomer composition. Thereafter, the polymerizable monomers contained in the particles are polymerized using an initiator or the like to obtain toner particles. By utilizing the hydrogen abstraction reaction during this polymerization reaction, a certain amount of the polymerizable monomer reacts with the pre-polymerized crystalline vinyl resin, making it easy to control the crystalline vinyl resin to have desired physical properties.

[0142] After the polymerization is completed, the toner particles are filtered, washed, and dried, and external additives are added as needed, whereby toner can be obtained.

[0143] Examples of polymerization initiators include azo-based or diazo-based polymerization initiators such as 2,2'-azobis-(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, and azobisisobutyronitrile; and peroxide-based polymerization initiators such as benzoyl peroxide, tert-butyl peroxy-2-ethylhexanoate, t-butylperoxy pivalate, tert-butyl peroxyisobutyrate, tert-butyl peroxycaprylate, tert-butyl peroxyneodecanoate, methyl ethyl ketone peroxide, diisopropyl peroxydicarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, and lauroyl peroxide. Polymerization initiators that easily cause hydrogen abstraction reactions are peroxide-based polymerization initiators, which are suitable for use. Among them, initiators such as tert-butyl peroxy-2-ethylhexanoate, t-butylperoxy pivalate, tert-butyl peroxyisobutyrate, tert-butyl peroxycaprylate, and tert-butyl peroxyneodecanoate are more suitable for use.

[0144] The temperature during the polymerization reaction can be 15°C to 25°C higher than the 10-hour half-life temperature of the initiator. Within this range, hydrogen abstraction reactions tend to occur moderately, making it easy to control the crystalline vinyl resin to have the desired physical properties.

[0145] A chain transfer agent and / or a polymerization inhibitor can also be used.

[0146] The aqueous medium can contain inorganic and / or organic dispersion stabilizers.

[0147] Examples of inorganic dispersion stabilizers include phosphates such as hydroxyapatite, tricalcium phosphate, dicalcium phosphate, magnesium phosphate, aluminum phosphate, and zinc phosphate; carbonates such as calcium carbonate and magnesium carbonate; metal hydroxides such as calcium hydroxide, magnesium hydroxide, and aluminum hydroxide; sulfates such as calcium sulfate and barium sulfate; calcium metasilicate; bentonite; silica; and alumina.

[0148] Examples of organic dispersion stabilizers include polyvinyl alcohol, gelatin, methylcellulose, methylhydroxypropylcellulose, ethylcellulose, sodium carboxymethylcellulose, polyacrylic acid and its salts, and starch.

[0149] When an inorganic compound is used as a dispersion stabilizer, a commercially available product can be directly used, or in order to obtain finer particles, the above inorganic compound can be generated and used in the aqueous medium.

[0150] For example, in the case of calcium phosphates such as hydroxyapatite or tricalcium phosphate, an aqueous phosphate solution and an aqueous calcium solution can be mixed under vigorous stirring.

[0151] The aqueous medium may contain a surfactant. Examples of surfactants include anionic surfactants such as sodium dodecylbenzenesulfonate and sodium oleate; cationic surfactants; amphoteric surfactants; and nonionic surfactants.

[0152] The following describes methods for calculating and measuring various physical properties of toners and toner materials. <Separation of toner particles from toner>

[0153] Toner particles and external additives are separated from each other in the following manner, and the resulting toner particles can be used for analysis.

[0154] An amount of 160 g of sucrose (manufactured by Kishida Chemical Co., Ltd.) is added to 100 mL of deionized water and dissolved in a hot water bath to prepare an aqueous sucrose solution. An amount of 31 g of the aqueous sucrose solution and 6 mL of Contaminon N (a 10 mass% aqueous solution of a neutral detergent for cleaning precision measuring instruments, which is composed of a nonionic surfactant, an anionic surfactant, and an organic builder and has a pH value of 7, manufactured by FUJIFILM Wako Pure Chemical Corporation) are placed in a centrifuge tube to prepare a dispersion. To this dispersion, 1 g of toner is added, and the lumps of the toner are loosened with a spatula or the like.

[0155] The centrifuge tube is placed in a "KM Shaker" (model: V.SX) manufactured by Iwaki Industry Co., Ltd. and vibrated for 20 min under the condition of 350 reciprocating cycles per minute. After vibration, the solution is transferred to a glass tube (50 mL) for a swinging rotor and centrifuged with a centrifuge under the conditions of 3,500 rpm and 30 min.

[0156] In the glass tube that has been centrifuged, the toner particles are present in the uppermost layer, and external additives such as fine silica particles are present on the lower aqueous solution side. The toner particles in the upper layer are collected, filtered, washed with 2 L of flowing deionized water heated to 40°C, and the washed toner particles are taken out.

[0157] <Separation of chloroform-insoluble substances from components A, B, and resin in toner particles and measurement of the percentage content>

[0158] Precisely weigh 1.5 g of toner particles (W1 [g]) and place them in a pre-precisely weighed extraction thimble (trade name: No. 86R, size 28×100 mm, manufactured by Advantec Toyo Kaisha, Ltd.), and place the extraction thimble in a Soxhlet extractor. Use 200 mL of chloroform as the solvent and perform extraction for 18 hours at a reflux rate such that one solvent extraction cycle ends within approximately 5 minutes.

[0159] After the extraction is completed, take out the extraction thimble and air-dry it, then vacuum-dry it at 40 °C for 8 hours. Weigh the mass of the extraction thimble including the extraction residue, and subtract the mass of the extraction thimble to calculate the mass of the extraction residue (chloroform-insoluble matter) (W3 [g]). When recovering the chloroform-soluble matter (W2 [g]), it can be recovered by thoroughly distilling off the chloroform from the soluble matter in chloroform using an evaporator.

[0160] Next, determine the content of the resin component (W4 [g]) in the chloroform-insoluble matter by the following steps.

[0161] In a pre-weighed 30 mL magnetic crucible, precisely weigh 2 g of the chloroform-insoluble matter of the toner particles (Wa' [g]).

[0162] Place the magnetic crucible in an electric furnace, heat it at approximately 900 °C for 3 hours, and let it cool in the electric furnace. At room temperature, let the magnetic crucible cool in a desiccator for more than 1 hour. Weigh the mass of the crucible including the incineration residual ash, and subtract the mass of the crucible to calculate the mass of the incineration residual ash (Wb' [g]).

[0163] The mass (W5 [g]) of the incineration residual ash in the sample W1 [g] is calculated by the following formula.

[0164] W5 = W1 × (Wb' / Wa')

[0165] Next, the mass (W4 [g]) of resin C, which is the resin component excluding the incineration residual ash in the chloroform-insoluble matter of the toner particles, is calculated by the following formula.

[0166] W4 = W1 - W5

[0167] When the toner particles contain wax, the resin and wax must be separated from each other.

[0168] Separation of resin and wax is carried out by recycling HPLC, and components with a molecular weight of 2,000 or less are regarded as wax. The measurement method is described below. First, chloroform-soluble substances are separated by the above method and dissolved in chloroform. Then, the resulting solution is filtered through a solvent-resistant membrane filter "Maishori Disc" with a pore size of 0.2 μm (manufactured by Tosoh Corporation) to obtain a sample solution. The sample solution is adjusted so that the concentration of components soluble in chloroform is 1.0 mass%. Using this sample solution, measurement is carried out under the following conditions.

[0169] · Equipment: LC-Sakura NEXT (manufactured by Japan Analytical Industry Co., Ltd.)

[0170] · Column: JAIGEL 2H, 4H (manufactured by Japan Analytical Industry Co., Ltd.)

[0171] · Eluent: Chloroform

[0172] · Flow rate: 10.0 mL / min

[0173] · Oven temperature: 40.0 °C

[0174] · Sample injection volume: 1.0 mL

[0175] When calculating the molecular weight of the sample, a molecular weight calibration curve made using standard polystyrene resin (for example, trade names "TSK Standard Polystyrene F-850, F-450, F-288, F-128, F-80, F-40, F-20, F-10, F-4, F-2, F-1, A-5000, A-2500, A-1000 or A-500", manufactured by Tosoh Corporation) is used.

[0176] Based on the molecular weight curve thus obtained, the components with a molecular weight of 2,000 or less are repeatedly recovered to separate the resin component (W) and the wax component (Wd) in the chloroform-soluble substances of the toner. Then, the content (W6 [g]) of the resin component in the chloroform-soluble substances (W2) in the toner particles W1 [g] is calculated by the following formula.

[0177] W2 = W1 - W3

[0178] W6 = W2 × (Wc / (W + Wd)) × W1 × 0.01

[0179] When separating component A and component B from toner particles, the above resin component (W) in the chloroform-soluble matter of the toner particles is used as a sample. The sample is adjusted to a sample concentration of 0.1% by mass with chloroform. The solution is filtered through a 0.45 μm PTFE filter, and the residue on the filter is measured. The gradient polymer LC measurement conditions are as follows.

[0180] Equipment: UlTIMATE 3000 (manufactured by Thermo Fisher Scientific)

[0181] Mobile phase: A, chloroform (HPLC); B, acetonitrile (HPLC)

[0182] Gradient: 2 min (A / B = 0 / 100) → 25 min (A / B = 100 / 0) (the gradient change in the mobile phase is controlled linearly)

[0183] Flow rate: 1.0 mL / min

[0184] Injection: 1.0% by mass × 20 μL

[0185] Column: Tosoh TSKgel ODS (diameter 4.6 mm × length 150 mm × 5 μm)

[0186] Column temperature: 40 °C

[0187] Detector: Corona charged particle detector (Corona-CAD) (manufactured by Thermo Fisher Scientific)

[0188] For the time-signal intensity (μA) graph obtained by measurement, the time is converted into chloroform percentage (volume %). Thereafter, from the observed maxima, the maximum with the largest signal intensity and the maximum with the second largest signal intensity are selected. Among these two maxima, the maximum with a smaller chloroform percentage in the mobile phase is determined as maximum PA, and the maximum with a larger chloroform percentage in the mobile phase is determined as maximum PB. In addition, the minimum minimum value existing between PA and PB is determined as BAB, and the chloroform percentage at BAB is determined as VAB (volume %).

[0189] Thereafter, the above measurement is repeated 50 times. The region where the proportion of the mobile phase is 20.0% by volume or more and less than VAB volume % is recovered as the acetonitrile / chloroform solution of component A, and the region where the proportion of the mobile phase is VAB volume % or more and 95.0% or less is recovered as the acetonitrile / chloroform solution of component B. The acetonitrile / chloroform is distilled off sufficiently with an evaporator to collect component A (We [g]) and component B (Wf [g]).

[0190] The content (W7 [g]) of component A and the content (W8 [g]) of component B in the chloroform-soluble substance (W2) of the toner particles W1 [g] are calculated by the following formula.

[0191] W7 = W6 × We / (1.484 × 1.0 × 0.01 × 20 × 0.001 × 50)

[0192] W8 = W7 × Wf / (1.484 × 1.0 × 0.01 × 20 × 0.001 × 50)

[0193] Based on the mass of the resin component of the present disclosure, the content percentage (W9 [mass%]) of component A, the content percentage (W10 [mass%]) of component B, and the content percentage (W11 [mass%]) of the chloroform-insoluble substance of the resin component are calculated by the following formula.

[0194] W9 = W7 / (W6 + W4)

[0195] W10 = W8 / (W6 + W4)

[0196] W11 = W4 / (W6 + W4)

[0197] <Method for Measuring the Content Percentage of Unit (a) in the Resin Component, Chloroform-Soluble Substance W, and Component B>

[0198] The measurement of the content percentage of unit (a) in the resin component, chloroform-soluble substance W, and component B is carried out 1 by 1H-NMR under the following conditions.

[0199] Measuring device: FT NMR device JNM-EX400 (manufactured by JEOL Ltd.)

[0200] Measuring frequency: 400 MHz

[0201] Pulse condition: 5.0 μs

[0202] Frequency range: 10,500 Hz

[0203] Number of scans: 64

[0204] Measuring temperature: 30 °C

[0205] Sample: Prepared as follows

[0206] Put 50 mg of the sample to be measured into a sample tube with an inner diameter of 5 mm, add deuterated chloroform (CDCl3) as a solvent, and dissolve the resulting mixture in a thermostat at 40 °C to prepare the sample.

[0207] Analyze the obtained 1H-NMR spectra are used to identify the structure of the units. Here, the measurement of the percentage content of unit (a) in component B is described as an example. From the peaks attributable to the elements of unit (a) in the obtained 1 H-NMR spectrum, peaks that are independent of the peaks attributable to the elements of other units are selected, and the integral value S1 of this peak is calculated. For each of the other units contained in the resin, the integral value is calculated in the same manner.

[0208] When component B consists of unit (a) and other units, the percentage content of unit (a) is determined as follows using the integral value S1 and the integral value S2 of the peaks of the other units. n1 and n2 each represent the number of hydrogen atoms in the element to which the target peak of each unit belongs.

[0209] Percentage content of unit (a) (mol%) = { (S1 / n1) / ((S1 / n1) + (S2 / n2))} × 100

[0210] Also, when there are two or more other units, the percentage content of unit (a) can be calculated in the same manner (using S3... Sx and n3... nx).

[0211] When using a monomer that does not contain hydrogen atoms as a constituent element other than vinyl, 13 C-NMR is measured in a single-pulse mode, where the nucleus to be measured is 13 C, and the percentage content is calculated in the same manner as through 1 H-NMR. Multiply the percentage (mol%) of each unit calculated by the above method by the molecular weight of each unit to convert the percentage content of each unit to a mass percentage. <Measurement of the storage modulus of the toner particles and Group B at 100 °C>

[0212] The storage modulus is measured using an MCR302 (manufactured by Anton Paar GmbH). The measurement method for the storage modulus of the toner particles at 100 °C will be described below.

[0213] Weigh 120 mg of toner particles and use a tablet press to form them at 20 kN for 1 minute to obtain a disc-shaped sample with a diameter of 8 mm.

[0214] Place the obtained sample in the measuring tool under the following conditions.

[0215] Measuring tool name: Measuring plate PP08 / SD: 8 mm, sandblasted Set conditions: 80 °C, 0.1 N

[0216] Next, measure the viscoelasticity under the following conditions.

[0217] Frequency: 1 Hz

[0218] Normal force: 100 mN

[0219] Applied strain: changing from 0.5% to 7.0% at 0.22% / min

[0220] Measurement was carried out for 30 minutes while increasing the temperature from 70 °C to 130 °C at 2 °C / min. The sampling pitch at this time was 1 point / 0.5 min.

[0221] During measurement, the calculated storage modulus (Pa) at 100 °C was determined as the storage modulus G'(T) of the toner particles at 100 °C. Similarly, the storage modulus at 100 °C obtained when component B was used as the sample was determined as the storage modulus G'(B).

[0222] <Method for measuring the molecular weight (weight-average molecular weight Mw) of component B>

[0223] The molecular weight (weight-average molecular weight Mw) of the THF-soluble matter of component B was measured by gel permeation chromatography (GPC) as follows.

[0224] First, component B was dissolved in tetrahydrofuran (THF) at room temperature for 24 hours. The resulting solution was filtered through a solvent-resistant membrane filter "Maishori Disc" with a pore size of 0.2 μm (manufactured by Tosoh Corporation) to obtain a sample solution. The sample solution was adjusted so that the concentration of the components soluble in THF was 0.8 mass%. Using this sample solution, measurements were carried out under the following conditions.

[0225] · Equipment: HLC8120 GPC (detector: RI) (manufactured by Tosoh Corporation)

[0226] · Column: Shodex KF-801, 802, 803, 804, 805, 806 and 807, seven-column set (manufactured by Resonac Holdings Corporation)

[0227] · Eluent: tetrahydrofuran (THF)

[0228] · Flow rate: 1.0 mL / min

[0229] · Oven temperature: 40.0 °C

[0230] · Sample injection volume: 0.10 mL

[0231] When calculating the molecular weight (weight-average molecular weight Mw) of a sample, a molecular weight calibration curve prepared using a standard polystyrene resin (e.g., trade names "TSK Standard Polystyrene F-850, F-450, F-288, F-128, F-80, F-40, F-20, F-10, F-4, F-2, F-1, A-5000, A-2500, A-1000, or A-500" manufactured by Tosoh Corporation) is used.

[0232] Example

[0233] More specific descriptions will be given below with reference to examples. In the following formulations, "parts" means "parts by mass" unless otherwise specified.

[0234] (Preparation of Resin A1)

[0235] The following materials were added to an autoclave equipped with a decompression device, a water separation device, a nitrogen introduction device, a temperature measurement device, and a stirring device.

[0236] · Terephthalic acid 25.3 parts

[0237] · Propylene oxide (2 mol) adduct of bisphenol A 74.7 parts

[0238] · Potassium titanyl oxalate (catalyst) 0.02 parts

[0239] Subsequently, the materials were reacted at 220 °C for 5 hours under normal pressure in a nitrogen atmosphere, and then reacted at 220 °C for 3 hours under reduced pressure. After cooling, the resulting product was pulverized to obtain Resin A1. The weight-average molecular weight (Mw) of Resin A1 was 10,280.

[0240] (Preparation of Resin A2)

[0241] 50.0 parts of xylene were charged into an autoclave, purged with nitrogen, and then stirred and heated to 185 °C in a closed state. A mixed solution of 79.0 parts of styrene, 17.0 parts of n-butyl acrylate, 3.1 parts of divinylbenzene, 0.9 parts of acrylic acid, and 1.0 part of di-tert-butyl peroxide and 20.0 parts of xylene was continuously added dropwise to the autoclave over 3 hours, thereby performing polymerization while controlling the temperature inside the autoclave at 185 °C. Further, the polymerization was completed by maintaining the temperature at this level for 1 hour, and the solvent was removed to obtain Resin A2. The weight-average molecular weight (Mw) of Resin A2 was 60,000.

[0242] (Preparation of Resin B1)

[0243] In a reaction vessel equipped with a reflux condenser, a stirrer, a thermometer, and a nitrogen inlet tube, the following materials were charged in a nitrogen atmosphere.

[0244] · 100.0 parts of toluene

[0245] · 100.0 parts of monomer composition

[0246] (The monomer composition is a mixture of the following monomers in the following proportions)

[0247] · 60.0 parts of behenyl acrylate

[0248] · 20.0 parts of styrene

[0249] · 10.0 parts of methacrylonitrile

[0250] · 10.0 parts of N-vinyl-2-pyrrolidone

[0251] · The polymerization initiator tert-butyl peroxyneodecanoate (Perbutyl PV, manufactured by NOF Corporation), 0.5 parts by mass

[0252] The above materials were stirred in a reaction vessel at 200 rpm and subjected to a polymerization reaction at an elevated temperature of 70 °C for 12 hours to obtain a solution in which the polymer in the monomer composition was dissolved in toluene. Subsequently, the solution was cooled to 25 °C and then poured into 1000.0 parts of methanol with stirring to precipitate methanol-insoluble substances. The resulting insoluble substances were separated by filtration, further washed with methanol, and then vacuum-dried at 40 °C for 24 hours to obtain Resin B1. The physical properties of Resin B1 are shown in Table 1.

[0253] (Preparation of Resins B2 to B6)

[0254] Crystalline Resins B2 to B6 were prepared in the same manner as Resin B1 except that the addition amounts of the monomer composition were changed as shown in Table 1. The physical properties of Resins B2 to B6 are shown in Table 1.

[0255] Table 1

[0256]

[0257] Polymerization initiator: tert-butyl peroxyneodecanoate (Perbutyl PV, manufactured by NOF Corporation)

[0258] <Example 1>

[0259] [Production of toner by suspension polymerization method]

[0260] (Production of toner particles 1)

[0261] Prepare a mixture of the following materials.

[0262] · 45.0 parts of styrene

[0263] · 15.0 parts of n-butyl acrylate

[0264] · 6.5 parts of Pigment Blue 15:3 (colorant)

[0265] The mixture was placed in a grinder (manufactured by Nippon Coke & Engineering Co., Ltd.) and dispersed for 2 hours at 200 rpm using zirconia beads with a diameter of 5 mm to obtain a raw material dispersion liquid.

[0266] Separately, 735.0 parts of deionized water and 16.0 parts of trisodium phosphate (dodecahydrate) were added to a container equipped with a high-speed stirring device HOMO MIXER (manufactured by PRIMIX Corporation) and a thermometer, and heated to 60 °C with stirring at 12,000 rpm. An aqueous calcium chloride solution in which 9.0 parts of calcium chloride (dihydrate) was dissolved in 65.0 parts of deionized water was put therein, and stirred at 12,000 rpm for 30 minutes while maintaining the temperature at 60 °C. 10% hydrochloric acid was added to the mixture to adjust the pH to 6.0, thereby obtaining an aqueous medium in which an inorganic dispersion stabilizer containing hydroxyapatite was dispersed in water.

[0267] Subsequently, the raw material dispersion liquid was transferred to a container equipped with a stirring device and a thermometer, and heated to 60 °C with stirring at 100 rpm. The following materials were added thereto.

[0268]

[0269] The mixture was stirred at 100 rpm for 30 minutes while maintaining the temperature at 60 °C, then 8.0 parts of tert-butyl peroxyneodecanoate (Perbutyl PV, manufactured by NOF Corporation) was added as a polymerization initiator and stirred for 1 minute. Thereafter, the resulting mixture was put into an aqueous medium stirred at 12,000 rpm with a high-speed stirring device. While maintaining the temperature at 60 °C, stirring was continued at 12,000 rpm with the high-speed stirring device for 20 minutes to obtain a granulation liquid.

[0270] The granulation liquid was transferred to a reaction vessel equipped with a reflux condenser, a stirrer, a thermometer and a nitrogen inlet tube, and heated to 76 °C with stirring at 150 rpm under a nitrogen atmosphere. While maintaining the temperature at 76 °C, a polymerization reaction was carried out at 150 rpm for 6 hours to obtain a toner particle dispersion liquid.

[0271] The obtained toner particle dispersion was cooled to 45°C while stirring at 150 rpm, and then heat-treated for 5 hours while maintaining the temperature at 45°C. Thereafter, while continuing to stir, dilute hydrochloric acid was added until the pH reached 1.5 to dissolve the dispersion stabilizer. The solid was separated by filtration, washed thoroughly with deionized water, and then vacuum-dried at 30°C for 24 hours to obtain toner particles 1.

[0272] (Preparation of Toner 1)

[0273] To 98.0 parts of toner particles 1, 2.0 parts of fine silica particles (hydrophobized with hexamethyldisilazane; number-average primary particle size of 10 nm; BET specific surface area of 170 m 2 / g) were added as an external additive, and the mixture was mixed at 3,000 rpm for 15 minutes using a Henschel mixer (manufactured by Nippon Coke & Engineering Co., Ltd.) to obtain toner 1. The physical properties, etc. of the obtained toner 1 are shown in Table 3.

[0274] <Examples 2 to 23>

[0275] Except for changing the types and addition amounts of the polymerizable monomers used, the addition amount of the polymerization initiator, the types and addition amounts of the release agents, other additives, the reaction temperature, and the reaction time as shown in Table 2, toner particles 2 to 23 were obtained in the same manner as in Example 1.

[0276] Furthermore, the same external addition as in Example 1 was performed to obtain toners 2 to 23. The physical properties of the toners are shown in Table 3.

[0277] <Comparative Examples 1 to 6>

[0278] Except for changing the types and addition amounts of the polymerizable monomers used, the addition amount of the polymerization initiator, the types and addition amounts of the release agents, other additives, the reaction temperature, and the reaction time as shown in Table 2, comparative toner particles 1 to 6 were obtained in the same manner as in Example 1.

[0279] Furthermore, the same external addition as in Example 1 was performed to obtain comparative toners 1 to 6. The physical properties of the toners are shown in Table 3.

[0280] <Comparative Example 7>

[0281] (Production of Comparative Toner Particles 7)

[0282] A mixture of the following materials was prepared.

[0283]

[0284] The mixture was placed in a grinder (manufactured by Nippon Coke & Engineering Co., Ltd.) and dispersed for 2 hours at 200 rpm using zirconia beads with a diameter of 5 mm to obtain a raw material dispersion. Separately, 735.0 parts of deionized water and 16.0 parts of trisodium phosphate (dodecahydrate) were added to a container equipped with a high-speed stirring device HOMO MIXER (manufactured by PRIMIX Corporation) and a thermometer, and heated to 60 °C with stirring at 12,000 rpm. An aqueous calcium chloride solution in which 9.0 parts of calcium chloride (dihydrate) was dissolved in 65.0 parts of deionized water was put therein, and the mixture was stirred at 12,000 rpm for 30 minutes while maintaining the temperature at 60 °C. 10% hydrochloric acid was added to the mixture to adjust the pH to 6.0, thereby obtaining an aqueous medium in which an inorganic dispersion stabilizer containing hydroxyapatite was dispersed in water.

[0285] Subsequently, the raw material dispersion was transferred to a container equipped with a stirring device and a thermometer, and heated to 60 °C with stirring at 100 rpm. The following materials were added thereto.

[0286] · 50.0 parts of behenyl acrylate

[0287] · 10.0 parts of DP18

[0288] The mixture was stirred at 100 rpm for 30 minutes while maintaining the temperature at 60 °C. Thereafter, 7.0 parts of tert-butyl peroxyneodecanoate (Perbutyl PV, manufactured by NOF Corporation) and 1.0 part of tert-butyl peroxyisobutyrate (L80, manufactured by ARKEMA Yoshitomi, Ltd.) were added as polymerization initiators, and the resulting mixture was stirred for 1 minute. Thereafter, the resulting mixture was put into an aqueous medium stirred at 12,000 rpm with a high-speed stirring device. While maintaining the temperature at 60 °C, stirring was continued at 12,000 rpm with the high-speed stirring device for 20 minutes to obtain a granulation liquid.

[0289] The granulation liquid was transferred to a reaction vessel equipped with a reflux condenser, a stirrer, a thermometer, and a nitrogen inlet tube, and heated to 70 °C with stirring at 150 rpm under a nitrogen atmosphere, and a first-stage polymerization reaction was carried out at 150 rpm for 5 hours. Thereafter, the temperature was raised to 90 °C, and a second-stage polymerization reaction was carried out for 5 hours while maintaining the temperature at 90 °C to obtain a toner particle dispersion liquid.

[0290] The obtained toner particle dispersion was cooled to 45°C while stirring at 150 rpm, and then heat-treated for 5 hours while maintaining the temperature at 45°C. Thereafter, while continuing to stir, dilute hydrochloric acid was added until the pH reached 1.5 to dissolve the dispersion stabilizer. The solid was separated by filtration, thoroughly washed with deionized water, and then vacuum-dried at 30°C for 24 hours to obtain comparative toner particles 7. Further, the same external addition as in Example 1 was performed to obtain comparative toner 7. The physical properties of the obtained comparative toner 7 are shown in Table 3.

[0291] <Comparative Example 8>

[0292] (Production Example of Comparative Toner Particles 8)

[0293] Mix the following materials.

[0294] · 40 parts of Resin A2

[0295] · 60 parts of Resin B6

[0296] The mixture was fed into a twin-screw kneader (manufactured by Kurimoto, Ltd., S5KRC kneader) at 1 kg / h, while 4.0 parts of isopropyl peroxy monocarbonate tert-butyl was fed as a radical reaction initiator at 0.1 kg / h. Kneading and extrusion were carried out at 160°C at 100 rpm for 5 minutes to carry out the reaction. Further, nitrogen was fed through the exhaust port, and mixing was carried out while removing the organic solvent. The kneaded product obtained by kneading was cooled to obtain comparative resin 8. Measurement using gel permeation chromatography (GPC) showed that Resin A2 and Resin B6 were partially reacted, resulting in an increase in the weight-average molecular weight. The content of the reacted resin in comparative resin 8 was 5% by mass.

[0297] Using a Henschel mixer (FM-75 type, manufactured by Nippon Coke & Engineering Co., Ltd.), the following materials were mixed at a rotation speed of 20 s -1 and a rotation time of 5 minutes.

[0298] · 100 parts of comparative resin 8

[0299] · 5.0 parts of hydrocarbon wax (Fischer-Tropsch wax: the peak temperature of the maximum endothermic peak of DSC is 90°C)

[0300] · 6.5 parts of C.I. Pigment Blue 15:3

[0301] Thereafter, the mixture was kneaded using a twin-screw kneader (PCM-30 type, manufactured by Ikegai Corporation) set at 130°C, a screw rotation speed of 250 rpm, and a discharge temperature of 130°C. The obtained kneaded product was cooled and coarsely pulverized to less than 1 mm using a hammer mill to obtain a pulverized product. The obtained pulverized product was finely pulverized using a mechanical pulverizer (T-250, manufactured by FREUND-TURBO CORPORATION).

[0302] Further, classification was performed using Faculty F-300 (manufactured by Hosokawa Micron Corporation) to obtain comparative toner particles 8 having a weight average particle diameter of about 6.0 μm. The operating conditions were as follows: classification rotor rotation speed, 130 s -1 ; dispersion rotor rotation speed, 120 s -1 .

[0303] Using a Henschel mixer type FM-10C (manufactured by Chemical Machinery Division of Nippon Coke & Engineering Co., Ltd.), the following materials were mixed under the conditions of a rotation speed of 30 s -1 and a rotation time of 10 minutes to obtain comparative toner 8.

[0304] · 100 parts of comparative toner particles 8

[0305] · 0.5 part of hydrophobized silica fine particles having a number average primary particle diameter of 15 nm

[0306] · 1.0 part of hydrophobized silica fine particles having a number average primary particle diameter of 80 nm

[0307] The physical properties of the obtained comparative toner 8 are shown in Table 3.

[0308]

[0309]

[0310] Table 3-1

[0311]

[0312] Table 3-2

[0313]

[0314] <Evaluation method of toner>

[0315] The toners of Examples 1 to 23 and Comparative Examples 1 to 8 were each evaluated as follows.

[0316] <1>Low-temperature fixing property

[0317] A processing cartridge filled with toner (a processing cartridge for a laser beam printer (LBP-712Ci, manufactured by CANON KABUSHIKI KAISHA)) was placed at 25 °C and 40% RH for 48 hours. Using a modified machine based on a laser beam printer (LBP-712Ci, manufactured by CANON KABUSHIKI KAISHA) modified to operate without a fixing unit, an unfixed image of an image pattern in which 10 mm × 10 mm square images are uniformly arranged at 9-point intervals over the entire recording paper was output. The toner loading on the recording paper was set to 0.80 mg / cm 2 and the fixing start temperature was evaluated. As the recording paper, A4 paper (Plover Bond paper: 105 g / m 2 , manufactured by Fox River Paper Company) was used.

[0318] As the fixing unit, an external fixing unit obtained by removing the fixing unit of a laser beam printer (LBP-712Ci, manufactured by CANON KABUSHIKI KAISHA) and modifying the fixing unit to operate outside the laser beam printer was used. While the fixing temperature of the external fixing unit was increased in 5 °C increments starting from 90 °C, fixing was performed at a processing speed of 360 mm / s.

[0319] The fixed image was visually observed, and the lowest temperature at which no cold smudging occurred was used as the fixing start temperature to evaluate the low-temperature fixing property. The evaluation results are shown in Table 4.

[0320] <2>Adhesion to paper (scrub resistance of the fixed image)

[0321] A fixed image was printed in the same manner as the evaluation in <1> above. The fixing temperature was set to a temperature 5 °C higher than the fixing start temperature. A soft thin paper (Dusper, manufactured by Ozu Corporation) was placed on the image area of the obtained fixed image, and the image area was rubbed back and forth five times while applying a load of 4.9 kPa from above the thin paper. The image density before and after rubbing was measured, and the decrease rate ΔD (%) of the image density was calculated by the following formula. ΔD (%) was used as an index of scrub resistance.

[0322] ΔD (%) = {(image density before rubbing - image density after rubbing) / image density before rubbing} × 100

[0323] The image density was measured using a color reflection densitometer (X-Rite 404A, manufactured by X-Rite Inc.). The evaluation results are shown in Table 4.

[0324] <3>Heat stain resistance

[0325] The highest temperature at which no heat stain is observed under the same conditions as the evaluation of <1> above is determined as the maximum fixing temperature, and the difference between the maximum fixing temperature and the minimum fixing temperature is determined as the fixable region. The evaluation results are shown in Table 4.

[0326] <4>Evaluation of glossiness

[0327] Use the fixed image at the fixing start temperature in the above <1> evaluation. Measure the glossiness value using a handheld glossiness meter PG-1 (manufactured by Nippon Denshoku Industries Co., Ltd.). Under the measurement conditions where the light emission angle and the light reception angle are set to 75° respectively, measure the image patterns of all images arranged at 9-point intervals, and evaluate their average value. The evaluation results are shown in Table 4. In the table, C.O. represents cold stain, and H.O. represents heat stain.

[0328] Table 4

[0329]

[0330] 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 accorded the broadest interpretation so as to cover all such modifications as well as equivalent structures and functions.

Claims

1. A toner, comprising: Toner particles containing a resin component, wherein the resin component contains a crystalline vinyl resin having a unit a represented by formula (1), the resin component contains the unit a in an amount of 15.0% by mass or more and 40.0% by mass or less based on the mass of the resin component, In formula (1), R 1 represents a hydrogen atom or a methyl group, and n represents an integer from 15 to 35, when the toner particles are subjected to Soxhlet extraction with chloroform for 18 hours to obtain chloroform-soluble substances, and components having a molecular weight of 2,000 or less are removed therefrom by recycling HPLC to obtain chloroform-soluble substances W, for the chloroform-soluble substances W, when acetonitrile is used as a poor solvent and chloroform is used as a good solvent, and the mobile phase is linearly changed from 100% by volume of acetonitrile to 100% by volume of chloroform, and gradient LC analysis is performed on the eluted components, in a graph in which the horizontal axis represents the percentage of chloroform in the mobile phase and the vertical axis represents the signal intensity of the eluted components detected by a charged particle detector, there are a plurality of maxima, the unit of the chloroform percentage is % by volume, and the unit of the signal intensity is μA, when among the maxima having the largest intensity and the second largest intensity in the plurality of maxima, the maximum having a smaller chloroform percentage in the mobile phase is maximum PA, the maximum having a larger chloroform percentage in the mobile phase is maximum PB, the minimum having the smallest intensity existing between maximum PA and maximum PB is minimum BAB, the chloroform percentage at minimum BAB is VAB % by volume, 20.0 < VAB < 95.0, the components having a chloroform percentage in the mobile phase of 20.0% by volume or more and less than VAB % by volume are component A, and the components having a chloroform percentage in the mobile phase of VAB % by volume or more and 95.0% by volume or less are component B, the resin component contains the component B in an amount of 40.0% by mass or more and 80.0% by mass or less based on the mass of the resin component, when the content of the unit a in the chloroform-soluble substances W is WC % by mass and the content of the unit a in the component B is WB % by mass, WC and WB satisfy formula (2), WB / WC ≥ 0.70 (2), and when the storage elastic modulus of the toner particles at 100°C is G'(T) and the storage elastic modulus of the component B at 100°C is G'(B), G'(T) and G'(B) satisfy formulas (3) and (4), 5.0 × 10 3 Pa ≤ G'(T) ≤ 1.0 × 10 5 Pa (3) 2.0 × 10 3 Pa ≤ G'(T) - G'(B) ≤ 6.0 × 10 3 Pa (4)。 2. The toner according to claim 1, wherein the component B contains the unit a in an amount of 25.0% by mass or more and 50.0% by mass or less based on the mass of the component B.

3. The toner according to claim 1 or 2, wherein the weight average molecular weight Mw of the component B is 30,000 or more and 200,000 or less.

4. The toner according to claim 1 or 2, wherein the resin component contains the component A in an amount of 10.0% by mass or more and 60.0% by mass or less based on the mass of the resin component. 5 . The toner according to claim 1 , wherein the resin component contains a chloroform-insoluble matter in an amount of 3.0% by mass or more and 15.0% by mass or less based on the mass of the resin component.

6. The toner according to claim 1 or 2, wherein the toner particles contain wax, and The wax is at least one selected from the group consisting of esters of alcohols having a valence of not less than 4 and not more than 8 and aliphatic monocarboxylic acids and ester waxes of carboxylic acids having a valence of not less than 4 and not more than 8 and aliphatic monoalcohols. 7 . The toner according to claim 1 , wherein the toner particles have a core-shell structure including a core comprising the crystalline vinyl resin and a shell comprising a non-crystalline resin. 8 . The toner according to claim 1 , wherein the component B has a lactam structure. 9 . The toner according to claim 8 , wherein the lactam structure comprises a unit having a five-membered ring lactam structure.

10. The toner according to claim 1 or 2, wherein the crystalline vinyl resin comprises a crystalline vinyl resin obtained by polymerizing a vinyl monomer including a (meth)acrylate for introducing the unit a, and then further reacting other vinyl monomers by a hydrogen abstraction reaction.

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