toner

Abstract

To provide a toner that attains a low temperature fixation property and a resistance to degradation and can output images with less unevenness of gloss.SOLUTION: The present invention relates to a toner including a binder resin and an ester compound, the binder resin containing a styrene-acrylic resin having a unit derived from a macro-monomer and a unit with long-chain alkyl in a side chain, the SP values of the unit derived from the macro monomer, the unit with a long-chain alkyl in a side chain, and the ester compound being in a special relation.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a toner used in a recording method utilizing electrophotography or electrostatic recording. [Background technology]

[0002] Electrophotographic image forming apparatuses are increasingly required to have high image quality, long life, and energy savings, and toner performance improvements are being sought to meet these demands. Furthermore, in recent years, there has been a growing demand for high image quality even in monochrome image forming apparatuses. This is due to the fact that the output of high-resolution text and photographs, even in black images, has become increasingly common worldwide. Regarding the performance improvement of monochrome image forming devices, there is a strong demand for improved low-temperature fixability in order to save energy. Various technologies have been proposed, and toners with improved low-temperature fixability are already on the market. Meanwhile, improvements have also been made to improve image quality, including improvements in character sharpness, density unevenness, gloss unevenness, and the reproducibility of fine images. In particular, when outputting high-resolution images in black, gloss unevenness is easily noticeable, so extremely high levels of gloss unevenness are required. One cause of gloss unevenness is the difference in light reflection between areas where the toner has melted and areas where agglomerates remain, due to differences in the amount of localized toner deformation during fixing. In other words, to resolve this gloss unevenness, it is necessary to improve low-temperature fixability while minimizing the difference in the amount of toner deformation during fixation. From the perspective of long life, recent trends have led to demands for longer cartridge life through reduced toner consumption and increased toner capacity within cartridges, enabling the same cartridge to be used for longer periods of time, from the perspective of ease of maintenance. When the same cartridge is used for extended periods, the toner is subject to friction with cartridge components, making it more susceptible to deterioration. In addition to changes in the properties of the toner surface, cracking and chipping due to high shear are often the cause of this deterioration. These changes can lead to contamination of components and a decrease in the toner's fluidity and charging properties, ultimately resulting in image defects. As demands for toner become more sophisticated, it is necessary to address these issues at a high level. As a specific solution, with regard to low-temperature fixability, it is important to first make the binder resin of the toner plasticized during fixing, creating a state in which it is easy to fuse. In particular, there are various means for improving low-temperature fixability, and it is generally possible to improve low-temperature fixability by using a toner having a binder resin designed to be easily plasticized. However, this method results in a small portion of the resin remaining fluid even when not being fixed, posing problems with storage stability and toner degradation over long-term use. Patent Document 1 proposes a toner that improves low-temperature fixability by adding a crystalline material to the toner, while incorporating a long-chain alkyl monomer into the binder resin (binder) to increase the compatibility between the binder and the crystalline material during fixation. From the perspective of extending product life, hardening the toner can make it more resistant to degradation. However, simply hardening the toner tends to deteriorate low-temperature fixability. Patent Document 2 proposes a toner that improves hot offset resistance and low-temperature fixability by using a specific monoester compound, while introducing a radical-reactive polymer called a macromonomer into the binder to improve cracking resistance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-035506 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-198569 Summary of the Invention [Problem to be solved by the invention]

[0004] Through our research, we have found that toners designed to promote binder plasticity by using a crystalline material as a plasticizer, as described in Patent Document 1, have problems with degradation. This is due to the fact that long-term use in printers designed for high-speed image output places a heavy load on the toner, making it prone to cracking. Furthermore, the toner described in Patent Document 2 achieves both low-temperature fixability and crack prevention, but gloss unevenness was observed during fixation in models designed for high-speed image output and monochrome printers with low fixing pressure. This is thought to be due to uneven melting caused by the presence of a melt-promoting component called a monoester and a curing component called a macromonomer during fixation. Therefore, an object of the present invention is to provide a toner that can output an image with little gloss unevenness while satisfying both low-temperature fixability and resistance to deterioration. [Means for solving the problem]

[0005] The present inventors have discovered that the above problem can be solved by a toner using a binder that uses an ester compound and a macromonomer that have a binder plasticizing effect, while also incorporating a long-chain alkyl monomer that is compatible with both the ester compound and the macromonomer. That is, the present invention provides a binder resin and an ester compound. (excluding polymers) 1. A toner having toner particles having The binder resin contains a styrene-acrylic resin having a unit derived from a macromonomer and a monomer unit represented by the following formula (1):

[0006] [ka] (In formula (1), R 1 represents a hydrogen atom or a methyl group, and R 2 represents a linear alkyl group having 10 to 14 carbon atoms. the ester compound is at least one ester compound selected from the group consisting of an ester compound represented by the following formula (2), an ester compound represented by the following formula (3), and an ester compound represented by the following formula (4),

[0007] [ka] (In formula (2), formula (3) and formula (4), 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 independently represents a linear alkyl group having 14 to 24 carbon atoms. The SP value of the macromonomer-derived unit is SPa (J / cm 3 ) 1 / 2 The SP value of the monomer unit represented by formula (1) is SPb (J / cm 3 ) 1 / 2 The SP value of the ester compound is SPc (J / cm 3 ) 1 / 2 When The SPa is 19.50 or more and 20.50 or less, The toner is characterized in that the SPa, the SPb, and the SPc satisfy the following relational formula (a), the following relational formula (b), and the following relational formula (c). SPa-SPb≦2.0 (a) SPb-SPc≦1.5 (b) SPa-SPc≧2.0 (c) [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a toner that can output an image with little gloss unevenness while achieving both low-temperature fixability and resistance to deterioration. DETAILED DESCRIPTION OF THE INVENTION

[0009] In the present disclosure, unless otherwise specified, the expressions "XX or more and YY or less" and "XX to YY" representing a numerical range mean a numerical range including the endpoints, that is, the lower limit and the upper limit.

[0010] A monomer unit is a reacted form of a monomer substance in a polymer. For example, one section of carbon-carbon bond in the main chain of a polymer formed by polymerizing a vinyl monomer in a polymer is considered to be one unit.

[0011] The crystalline resin and crystalline material refer to a resin or material that shows a clear endothermic peak in differential scanning calorimetry.

[0012] Furthermore, the “macromonomer-derived unit” according to the present invention will be referred to as unit A, the “monomer unit represented by formula (1)” as unit B, and the “ester compound selected from formulae (2) to (4)” as compound C.

[0013] Hereinafter, embodiments of the present invention will be described in more detail, but the present invention is not limited to these.

[0014] The present inventors have discovered a method for solving the above problems by using a toner that uses a binder that uses an ester compound and a macromonomer that have a binder plasticizing effect, and also introduces a long-chain alkyl monomer that is compatible with both the ester compound and the macromonomer.

[0015] That is, the toner of the present invention is a toner having toner particles containing a binder resin and an ester compound, The binder resin contains a styrene-acrylic resin having a unit derived from a macromonomer and a monomer unit represented by the following formula (1):

[0016] [ka] (In formula (1), R 1 represents a hydrogen atom or a methyl group, and R 2 represents a linear alkyl group having 10 to 14 carbon atoms.

[0017] the ester compound is at least one ester compound selected from the group consisting of an ester compound represented by the following formula (2), an ester compound represented by the following formula (3), and an ester compound represented by the following formula (4),

[0018] [ka] (In formula (2), formula (3) and formula (4), 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 independently represents a linear alkyl group having 14 to 24 carbon atoms.

[0019] The SP value of the macromonomer-derived unit is SPa (J / cm 3 ) 1 / 2 The SP value of the monomer unit represented by formula (1) is SPb (J / cm 3 ) 1 / 2 The SP value of the ester compound is SPc (J / cm 3 ) 1 / 2 When The SPa is 19.50 or more and 20.50 or less, The SPa, SPb, and SPc are characterized in that they satisfy the following relational formula (a), the following relational formula (b), and the following relational formula (c). SPa-SPb≦2.0 (a) SPb-SPc≦1.5 (b) SPa-SPc≧2.0 (c)

[0020] The binder resin in the toner of the present invention must contain a styrene-acrylic resin having a unit derived from a macromonomer and a monomer unit represented by the formula (1).

[0021] The macromonomer in the present invention refers to a high molecular weight monomer having a reactive functional group, and is a monomer having a unit formed by polymerizing a polymerizable monomer.

[0022] Styrene-acrylic resins having units derived from macromonomers have a branched structure, which increases stress against impact. As a result, the toner has crack-resistant properties. Furthermore, the toner of the present invention must contain an ester compound (compound C) of the above formulas (2) to (4). The inclusion of an ester compound having a specific structure promotes plasticization of the toner during fixing, improving low-temperature fixing properties.

[0023] The monomer unit (unit B) represented by the formula (1) has an alkyl group. The styrene-acrylic resin has a structure similar to those of the formulae (2) to (4) when the styrene-acrylic resin has an alkyl group on its side chain, which promotes the plasticizing effect of the styrene-acrylic resin when the compound C melts during fixing.

[0024] In the toner of the present invention, the unit B has a structure of the following formula (1).

[0025] [ka] (In formula (1), R 1 represents a hydrogen atom or a methyl group, and R 2 represents a linear alkyl group having 10 to 14 carbon atoms.

[0026] R 2 It is more preferable that the carbon number is 12 (lauryl acrylate). If the carbon number is less than 10, the affinity with the unit A is impaired, causing uneven melting during fixation and uneven gloss. If the carbon number is more than 14, the affinity with the ester compound is impaired, making it difficult for the resin to be plasticized during fixation. Furthermore, the mobility of unit A during fixation is impaired, causing uneven gloss.

[0027] The styrene-acrylic resin is preferably a styrene-acrylic resin having the unit B in an amount of 1% by mass to 15% by mass. This range allows for the plasticizing effect of compound C and the associated induction of molecular motion of unit A, resulting in good low-temperature fixability and the production of images with reduced gloss unevenness. Furthermore, the styrene-acrylic resin is more preferably a styrene-acrylic resin having the unit B in an amount of 2% by mass to 10% by mass.

[0028] The content of the unit B in the styrene-acrylic resin can be adjusted by the amount of the precursor monomer having an unsaturated bond added during polymerization.

[0029] The styrene-acrylic resin contains the unit A.

[0030] Specific examples of macromonomers that serve as precursors of unit A include polymers obtained by polymerizing styrene, styrene derivatives, methacrylic acid esters, acrylic acid esters, acrylonitrile, methacrylonitrile, etc., either alone or in combination, and macromonomers having a polysiloxane skeleton. Among these, polymers having a glass transition temperature higher than that of the binder resin are preferred, and copolymer macromonomers of styrene and methacrylic acid esters and / or acrylic acid esters, and polymethacrylic acid ester macromonomers are preferred. In particular, macromonomers having a unit represented by formula (3) in the main chain portion of the macromonomer are preferred.

[0031] [ka] (Equation (3) is R 1 and R 2 indicates a methyl group.)

[0032] From the viewpoint of imparting elasticity and polymerizability, the macromonomer is preferably a monomer having a number average molecular weight of 1,000 to 30,000, more preferably 2,000 to 10,000, and particularly preferably 5,000 to 10,000. The glass transition temperature of the macromonomer is preferably 60°C to 110°C, and more preferably 70°C to 105°C.

[0033] The styrene-acrylic resin preferably contains the unit A in an amount of 0.01% by mass or more and 10.00% by mass or less, more preferably 0.05% by mass or more and 1.00% by mass or less.

[0034] In the toner of the present invention, compound C is at least one ester compound selected from the group consisting of ester compounds represented by the following formula (2), ester compounds represented by the following formula (3), and ester compounds represented by the following formula (4).

[0035] [ka] (In formula (2), formula (3) and formula (4), 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 independently represents a linear alkyl group having 14 to 24 carbon atoms.

[0036] In the above formulas (2), (3), and (4), ethylene glycol distearate (R 31 =-C2H4-, R 32 =R 33 =-C 17 H 35 ), ethylene glycol dipalmitate (R 31 =-C2H4-, R 32 =R 33 =-C 15 H 31), ethylene glycol dibehenate (R 31 =-C2H4-, R 32 =R 33 =-C 21 H 43 ), Dibehenyl Sebacate (R 41 =-C8H 16 -, R 42 =R 43 =-C 21 H 43 ), Behenyl stearate (R 51 =C 17 H 35 , R 52 =C 22 H 45 ), Stearyl Behenate (R 51 =C 21 H 43、 R 52 =C 18 H 37 ), Behenyl Behenate (R 51 =C 21 H 43 , R 52 =C 22 H 45 ), is preferred.

[0037] The content of compound C contained in the ester compound in the toner of the present invention is preferably 50% by mass or more and 100% by mass or less, and more preferably 95% by mass or more and 100% by mass or less.

[0038] The content of the ester compound in the toner of the present invention is preferably 5 parts by mass or more and 30 parts by mass or less, and more preferably 10 parts by mass or more and 30 parts by mass or less, relative to 100 parts by mass of the binder resin. By including 5 parts by mass or more, the effects of the present invention can be stably obtained. On the other hand, by including 30 parts by mass or less, it becomes easier to achieve both storage stability and stability.

[0039] The acid value of compound C is preferably 0.01 mgKOH / g or more and 2.0 mgKOH / g or less, more preferably 0.03 mgKOH / g or more and 1.0 mgKOH / g or less, and even more preferably 0.05 mgKOH / g or more and 0.5 mgKOH / g or less. The acid value of compound C is a value measured in accordance with JIS K 0070 using the test method for acid value of chemical products established by the Japanese Industrial Standards. The measurement method will be described in detail below.

[0040] When the acid value of compound C is 0.01 mgKOH / g or more and 2.0 mgKOH / g or less, the compound contains an appropriate amount of carboxylic acid groups derived from unreacted fatty acids, which tends to facilitate stable formation of droplets of the polymerizable monomer composition in the droplet formation step, and as a result, the particle size of the toner particles tends to be uniform.

[0041] The hydroxyl value of compound C is preferably 0.1 mgKOH / g or more and 15 mgKOH / g or less, more preferably 0.3 mgKOH / g or more and 10 mgKOH / g or less, even more preferably 0.5 mgKOH / g or more and 5.0 mgKOH / g or less, and particularly preferably 1.0 mgKOH / g or more and 4.0 mgKOH / g or less. The hydroxyl value of compound C is a value measured in accordance with JIS K 0070 using the test method for hydroxyl values ​​of chemical products established by the Japanese Industrial Standards.

[0042] When the hydroxyl value of compound C is 0.1 mgKOH / g or more and 15 mgKOH / g or less, a suitable amount of hydroxyl groups derived from unreacted raw materials is present in the wax, which tends to facilitate stable formation of droplets of the polymerizable monomer composition in the droplet formation step, and as a result, the particle size of the toner particles tends to be uniform.

[0043] The method for producing compound C is not particularly limited, but examples thereof include a synthesis method using an oxidation reaction, synthesis from a carboxylic acid or a derivative thereof, an ester group introduction reaction represented by a Michael addition reaction, a method using a dehydration condensation reaction from a carboxylic acid compound and an alcohol compound, a reaction from an acid halide and an alcohol compound, and a transesterification reaction.

[0044] A catalyst can be used appropriately in the production of compound C. As the catalyst, a general acidic or alkaline catalyst used in esterification reactions, such as zinc acetate or a titanium compound, is preferred. After the esterification reaction, the target product may be purified by recrystallization, distillation, or the like.

[0045] Specific examples of the preparation of compound C are shown below, but the present invention is not limited to these examples.

[0046] First, the raw materials, alcohol monomer and carboxylic acid monomer, are added to a reaction vessel. The molar ratio of the alcohol monomer to the carboxylic acid monomer is adjusted appropriately according to the chemical structure of the target monoester compound. That is, the alcohol monomer and the carboxylic acid monomer are mixed so that the molar ratio of alcohol monomer to carboxylic acid monomer is 1:1. Note that, taking into consideration the reactivity in the dehydration condensation reaction, either the alcohol monomer or the carboxylic acid monomer may be added in a slight excess over the above ratio.

[0047] Next, the mixture of alcohol monomer and carboxylic acid monomer is heated appropriately to carry out a dehydration condensation reaction. A basic aqueous solution and an appropriate organic solvent are added to the esterified crude product obtained by the dehydration condensation reaction, and the unreacted alcohol monomer and carboxylic acid monomer are deprotonated and separated into an aqueous phase. Compound C can then be obtained by appropriate water washing, solvent distillation, and filtration.

[0048] The toner of the present invention may contain a hydrocarbon wax. Specific examples include the following.

[0049] Examples of the wax include aliphatic hydrocarbons such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax.

[0050] The melting point of the wax is preferably from 60° C. to 85° C., more preferably from 65° C. to 80° C. By setting the melting point within this range, it becomes easier to achieve both storage stability and low-temperature fixability of the toner.

[0051] The SP value of the toner of the present invention was determined in the following manner according to the calculation method proposed by Fedors.

[0052] For low molecular weight compounds, the evaporation energy (Δei) (J / mol) and molar volume (Δvi) (cm) are calculated from the table in "Polym. Eng. Sci., 14(2), 147-154 (1974)." 3 / mol) and calculate using the following formula (5). Equation (5): σ m =(ΣΔei / ΣΔvi) 1 / 2

[0053] Next, the SP value of the repeating unit constituting the binder resin or resin (hereinafter also referred to as "resin, etc.") is determined as follows: Here, when the binder resin or resin is a vinyl resin (when a polymer constituting the resin is produced by the polymerization reaction of a vinyl monomer), the repeating unit constituting the resin means a molecular structure in a state in which the double bond of the vinyl monomer is cleaved by polymerization.

[0054] For example, the SP value of the repeating unit (σ m )(J / cm 3 ) 1 / 2 When calculating the evaporation energy (Δei) (J / mol) and molar volume (Δvi) (cm) for the atom or atomic group in the molecular structure of the repeating unit, refer to the table in "Polym. Eng. Sci., 14(2), 147-154 (1974)". 3 / mol) and calculate using the following formula (6). Equation (6): σ m=(ΣΔei / ΣΔvi) 1 / 2

[0055] In the toner of the present invention, the SP value of the macromonomer-derived unit is SPa (J / cm 3 ) 1 / 2 The SP value of the monomer unit represented by formula (1) is SPb (J / cm 3 ) 1 / 2 The SP value of the ester compound is SPc (J / cm 3 ) 1 / 2 where SPa is 19.50 or more and 20.50 or less, and SPa, SPb, and SPc satisfy the following relational formulas (a), (b), and (c). SPa-SPb≦2.0 (a) SPb-SPc≦1.5 (b) SPa-SPc≧2.0 (c)

[0056] Conventional toners containing macromonomers and ester compounds have an SP value difference of 2.0 (J / cm 3 ) 1 / 2 As a result, compatibility tends to be low. Therefore, the ester compound domain and the macromonomer unit are likely to phase-separate during toner production. As a result, when the ester compound domain melts during fixing, plasticization of the binder resin tends to progress locally. Meanwhile, the vicinity of the macromonomer unit is insufficient in ester compound, and the plasticization effect cannot be obtained during fixing. As a result, uneven melting of the toner occurs, resulting in uneven gloss.

[0057] In contrast, by introducing the unit B of the present invention into the resin together with the unit A, the performance can be significantly changed. Specifically, the unit B having an SP value intermediate between that of the unit A and the ester compound is introduced. First, the SP value difference between the ester compound and the unit B is 1.5 (J / cm 3 ) 1 / 2 By setting the SP value difference between unit A and unit B to 2.0 (J / cm 3 ) 1 / 2This results in a structure in which unit A and unit B tend to be close to each other in the resin. This allows the ester compound to be present in the vicinity of unit A in the toner during toner production due to the effect of unit B. As a result, the ester compound allows the entire toner to be plasticized uniformly, making it possible to suppress uneven gloss.

[0058] The SP value of unit B is SPb (J / cm 3 ) 1 / 2 , the SP value of compound C is SPc (J / cm 3 ) 1 / 2 When SPb-SPc≦1.5, the structure becomes easily miscible.

[0059] The SP value of the unit (unit A) derived from the macromonomer is SPa (J / cm 3 ) 1 / 2 must be 19.50 or more and 20.50 or less, SPa - SPb ≦ 2.0, and SPa - SPc ≧ 2.0. When the SP values ​​of unit A and compound C are 2.0 or more, the plasticizing effect of compound C can be suppressed from affecting unit A except during fixing. This maintains the elasticity of the toner during long-term use and suppresses cracking. Meanwhile, when the SP values ​​of unit A and unit B are close to each other, they can be located close to each other in the resin or molecule. Being located close to each other makes unit B more likely to be plasticized by the plasticizing effect of compound C during fixing. As a result, molecular motion is induced in unit A located nearby, making unit A more likely to move only during fixing. This reduces the likelihood of uneven melting on the image during fixing, thereby improving gloss unevenness.

[0060] SPa-SPb is preferably 1.7 (J / cm 3 ) 1 / 2 It is preferably 1.5 (J / cm 3 ) 1 / 2 The smaller the difference, the higher the affinity between unit A and unit B, which leads to the suppression of gloss unevenness. SPb-SPc is preferably 1.3 (J / cm 3 ) 1 / 2More preferably, it is 1.1 (J / cm 3 ) 1 / 2 The smaller the difference, the higher the affinity between unit B and compound C, leading to improved low-temperature fixability and suppression of gloss unevenness. SPa-SPc is preferably 2.5 (J / cm 3 ) 1 / 2 More preferably, 2.7 (J / cm 3 ) 1 / 2 The larger the difference, the less affinity there is between unit A and compound C, making it possible to suppress cracking of the toner during long-term use.

[0061] SPa, SPb, and SPc can be adjusted by the molecular structure. Specifically, they can be controlled by selecting the macromonomer that serves as the precursor of unit A, the precursor of unit B, and compound C.

[0062] The toner is not particularly limited as long as the toner particles contain a styrene-acrylic resin and an ester compound, and there is no particular limitation on the method of production thereof.

[0063] The toner particles can be produced by a pulverization method, or by a method of producing toner particles in an aqueous medium, such as a dispersion polymerization method, an association aggregation method, a solution suspension method, a suspension polymerization method, or an emulsion aggregation method.

[0064] However, from the viewpoint of controlling the state of existence of the ester compound, a method of producing toner particles in an aqueous medium is preferred, and from the viewpoint of controlling the toner shape, a suspension polymerization method is more preferred for producing toner particles.

[0065] The suspension polymerization method will be described below.

[0066] The suspension polymerization method involves uniformly dissolving or dispersing a polymerizable monomer and wax (and, if necessary, a colorant, polymerization initiator, crosslinking agent, charge control agent, and other additives) to obtain a polymerizable monomer composition. This polymerizable monomer composition is then dispersed in a continuous layer (e.g., an aqueous phase) containing a dispersant using an appropriate stirrer, and a polymerization reaction is simultaneously carried out to obtain toner particles having a desired particle size. The toner particles obtained by this suspension polymerization method (hereinafter also referred to as "polymerized toner particles") have an approximately spherical shape, and therefore the charge distribution is relatively uniform, which is expected to improve image quality.

[0067] In the production of polymerized toner particles, examples of the polymerizable monomer that constitutes the polymerizable monomer composition include the following.

[0068] It is preferable to use a monovinyl monomer as the polymerizable monomer. Examples of the monovinyl monomer include styrene, styrene derivatives such as vinyltoluene and α-methylstyrene, acrylic acid and methacrylic acid, acrylic acid esters such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and dimethylaminoethyl acrylate, methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, and dimethylaminoethyl methacrylate, nitrile compounds such as acrylonitrile and methacrylonitrile, amide compounds such as acrylamide and methacrylamide, and olefins such as ethylene, propylene, and butylene.

[0069] Among these, it is preferable that the monovinyl monomer contains at least one selected from the group consisting of styrene, a styrene derivative, an acrylic acid ester, and a methacrylic acid ester, and more preferably contains at least one selected from the group consisting of styrene and a styrene derivative, and at least one selected from the group consisting of an acrylic acid ester and a methacrylic acid ester, as the monovinyl monomer.

[0070] These monovinyl monomers can be used either alone or in combination of two or more.

[0071] The polymerizable monomer preferably contains the monovinyl monomer as a main component. Specifically, the content of the monovinyl monomer in the polymerizable monomer is preferably 50% by mass or more and 100% by mass or less.

[0072] Examples of polymerization initiators used in the polymerization production of toner particles include persulfates such as potassium persulfate and ammonium persulfate; azo compounds such as 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(2-methyl-N-(2-hydroxyethyl)propionamide), 2,2'-azobis(2-amidinopropane) dihydrochloride, 2,2'-azobis(2,4-dimethylvaleronitrile), and 2,2'-azobisisobutyronitrile; and organic peroxides such as di-t-butyl peroxide, benzoyl peroxide, t-butylperoxy-2-ethylhexanoate, t-butylperoxydiethylacetate, t-hexylperoxy-2-ethylbutanoate, diisopropyl peroxydicarbonate, di-t-butylperoxyisophthalate, and t-butylperoxyisobutyrate. These can be used alone or in combination of two or more. Among these, it is preferable to use organic peroxides, since they can reduce the amount of residual polymerizable monomers and provide excellent print durability.

[0073] Among organic peroxides, peroxyesters are preferred because they have good initiator efficiency and can reduce the amount of residual polymerizable monomers, and non-aromatic peroxyesters, i.e., peroxyesters without an aromatic ring, are more preferred.

[0074] As described above, the polymerization initiator may be added after the polymerizable monomer composition is dispersed in an aqueous medium and before droplets are formed, or may be added to the polymerizable monomer composition before it is dispersed in an aqueous medium.

[0075] The amount of the polymerization initiator used for polymerizing the polymerizable monomer composition is preferably 0.1 parts by mass or more and 20 parts by mass or less, more preferably 0.3 parts by mass or more and 15 parts by mass or less, and particularly preferably 1 part by mass or more and 10 parts by mass or less, relative to 100 parts by mass of the polymerizable monomer.

[0076] When the toner particles are produced by a polymerization method, a crosslinking agent may be added. The amount of the crosslinking agent added is preferably 0.001 to 15 parts by mass per 100 parts by mass of the polymerizable monomer.

[0077] The crosslinking agent is mainly a compound having two or more polymerizable double bonds. Specific examples include aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene, and derivatives thereof; ester compounds in which two or more carboxylic acids having carbon-carbon double bonds are ester-bonded to alcohols having two or more hydroxyl groups, such as ethylene glycol dimethacrylate and diethylene glycol dimethacrylate; other divinyl compounds such as N,N-divinylaniline and divinyl ether; and compounds having three or more vinyl groups.

[0078] These crosslinking agents can be used either alone or in combination of two or more.

[0079] The toner particles may also contain colorants. When color toners are produced, black, cyan, yellow, and magenta colorants can be used.

[0080] As the black colorant, for example, carbon black, titanium black, and magnetic powders such as iron zinc oxide and iron nickel oxide can be used.

[0081] Examples of cyan colorants that can be used include copper phthalocyanine compounds, their derivatives, and anthraquinone compounds, etc. Specific examples include CI Pigment Blue 2, 3, 6, 15, 15:1, 15:2, 15:3, 15:4, 16, 17:1, and 60.

[0082] Examples of yellow colorants that can be used include azo pigments such as monoazo pigments and disazo pigments, and condensed polycyclic pigments. Specific examples include CI Pigment Yellow 3, 12, 13, 14, 15, 17, 62, 65, 73, 74, 83, 93, 97, 120, 138, 155, 180, 181, 185, 186, and 213.

[0083] Examples of magenta colorants that can be used include azo pigments such as monoazo pigments and disazo pigments, and condensed polycyclic pigments, such as CI Pigment Red 31, 48, 57:1, 58, 60, 63, 64, 68, 81, 83, 87, 88, 89, 90, 112, 114, 122, 123, 144, 146, 149, 150, 163, 170, 184, 185, 187, 202, 206, 207, 209, 237, 238, 251, 254, 255, 269, and CI Pigment Violet 19.

[0084] Each colorant may be used alone or in combination of two or more. The amount of the colorant is preferably 1 part by mass or more and 10 parts by mass or less per 100 parts by mass of the polymerizable monomer.

[0085] As other additives, a positively or negatively chargeable charge control agent can be used to improve the chargeability of the toner.

[0086] The charge control agent is not particularly limited as long as it is a charge control agent generally used for toner. Among the charge control agents, a positively or negatively charged charge control resin is preferred because it has high compatibility with polymerizable monomers and can impart stable chargeability (charge stability) to toner particles. Furthermore, from the viewpoint of obtaining a positively charged toner, a positively charged charge control resin is more preferably used.

[0087] Examples of positively chargeable charge control agents include nigrosine dyes, quaternary ammonium salts, triaminotriphenylmethane compounds, and imidazole compounds, as well as preferably used charge control resins such as polyamine resins, quaternary ammonium group-containing copolymers, and quaternary ammonium base-containing copolymers. An example of a commercially available charge control resin is FCA-592P manufactured by Fujikura Chemical Co., Ltd.

[0088] Examples of negatively chargeable charge control agents include azo dyes containing metals such as Cr, Co, Al, and Fe, metal salicylate compounds, and metal alkylsalicylate compounds, as well as sulfonic acid group-containing copolymers, sulfonate salt group-containing copolymers, carboxylic acid group-containing copolymers, and carboxylic acid salt group-containing copolymers, which are preferably used as charge control resins.

[0089] The charge control agent is used in an amount of preferably 0.01 to 10 parts by mass, more preferably 0.03 to 8 parts by mass, per 100 parts by mass of the polymerizable monomer. When the amount of charge control agent added is 0.01 part by mass or more, fogging is less likely to occur. On the other hand, when the amount of charge control agent added is 10 parts by mass or less, print smearing is less likely to occur.

[0090] As other additives, it is preferable to use a molecular weight modifier when polymerizing the polymerizable monomer that becomes the binder resin after polymerization.

[0091] The molecular weight modifier is not particularly limited as long as it is one generally used as a molecular weight modifier for toners, but a molecular weight modifier having a sulfide group is preferred. Examples include mercaptans such as t-dodecyl mercaptan, n-dodecyl mercaptan, n-octyl mercaptan, and 2,2,4,6,6-pentamethylheptane-4-thiol; and thiuram disulfides such as tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, N,N'-dimethyl-N,N'-diphenylthiuram disulfide, and N,N'-dioctadecyl-N,N'-diisopropylthiuram disulfide. These molecular weight modifiers may be used alone or in combination of two or more.

[0092] The molecular weight modifier is used in a proportion of preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, relative to 100 parts by mass of the polymerizable monomer.

[0093] In a method for producing toner particles by polymerization, the above-mentioned raw materials for the toner particles are generally added appropriately, and the polymerizable monomer composition is uniformly dissolved or dispersed using a dispersing machine such as a homogenizer, a ball mill, or an ultrasonic dispersing machine, and then suspended in an aqueous medium containing a dispersing agent. At this time, if a high-speed dispersing machine such as a high-speed stirrer or an ultrasonic dispersing machine is used to quickly obtain the desired toner particle size, the particle size of the obtained toner particles will become sharper.

[0094] The polymerization initiator may be added simultaneously with the addition of other additives to the polymerizable monomer, or may be mixed immediately before suspending the polymerizable monomer in an aqueous medium. Alternatively, the polymerization initiator dissolved in the polymerizable monomer or solvent may be added immediately after granulation and before starting the polymerization reaction.

[0095] After granulation, a conventional stirrer may be used to stir the mixture to such an extent that the particle state is maintained and the particles are prevented from floating or settling.

[0096] When producing toner particles, known surfactants, organic dispersants, and inorganic dispersants can be used as dispersants. In particular, inorganic dispersants are preferred because they provide dispersion stability through their steric hindrance, which means they are resistant to changes in reaction temperature and are easy to wash away, without adversely affecting the toner. Examples of such inorganic dispersants include sulfates such as barium sulfate and calcium sulfate; carbonates such as barium carbonate, calcium carbonate, and magnesium carbonate; phosphates such as calcium phosphate; metal oxides such as aluminum oxide and titanium oxide; and metal hydroxides such as aluminum hydroxide, magnesium hydroxide, sodium hydroxide, and ferric hydroxide.

[0097] These inorganic dispersants are preferably used in an amount of 0.2 to 20 parts by mass per 100 parts by mass of the polymerizable monomer. The dispersants may be used alone or in combination. Furthermore, a surfactant may be used in an amount of 0.001 to 0.1 parts by mass.

[0098] In the step of polymerizing the polymerizable monomer, the polymerization temperature is preferably 50° C. or higher, more preferably 60 to 95° C. The polymerization reaction time is preferably 1 to 20 hours, more preferably 2 to 15 hours.

[0099] The toner particles are so-called core-shell type (also called "capsule type") polymer particles obtained by forming a core layer of polymer particles and a shell layer different from the core layer on the outside of the core layer. Core-shell type polymer particles can achieve a balance between lowering the fixing temperature and preventing aggregation during storage by coating the core layer made of a material with a low softening point with a material with a higher softening point.

[0100] The method for producing the core-shell type polymer particles using the above-mentioned polymer particles is not particularly limited, and they can be produced by a conventionally known method. Among them, an in situ polymerization method or a phase separation method is preferred from the viewpoint of production efficiency.

[0101] The method for producing core-shell type polymer particles by in situ polymerization will be described below.

[0102] Core-shell type polymer particles can be obtained by adding a polymerizable monomer for forming a shell layer (polymerizable monomer for shell) and a polymerization initiator to an aqueous medium in which polymer particles are dispersed, and polymerizing them.

[0103] As the polymerizable monomer for the shell, the same polymerizable monomers as those described above can be used. Among them, it is preferable to use monomers that can give polymers with a glass transition temperature (Tg) exceeding 80°C, such as styrene, acrylonitrile, and methyl methacrylate, either alone or in combination of two or more. Of these, it is preferable to use at least methyl methacrylate as the polymerizable monomer for the shell.

[0104] Examples of polymerization initiators used in the polymerization of the shell polymerizable monomer include water-soluble polymerization initiators such as metal persulfates, such as potassium persulfate and ammonium persulfate; and azo initiators, such as 2,2'-azobis(2-methyl-N-(2-hydroxyethyl)propionamide), 2,2'-azobis-(2-methyl-N-(1,1-bis(hydroxymethyl)2-hydroxyethyl)propionamide), 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine], and hydrates thereof. These initiators may be used alone or in combination of two or more. The amount of the polymerization initiator is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass, per 100 parts by mass of the shell polymerizable monomer.

[0105] When the phase separation method is used, it is preferable to add a polymer obtained by prepolymerizing a substance that forms the shell to the polymerizable monomer that forms the core. When a prepolymerized polymer is used, it is more preferable that the prepolymer is a reactive polymer having an unsaturated bond.

[0106] The polymerization temperature for the shell layer is preferably 50° C. or higher, more preferably 60 to 95° C. The polymerization reaction time is preferably 1 to 20 hours, more preferably 2 to 15 hours.

[0107] The resulting polymer particles can be filtered, washed, and dried as needed by known methods to obtain toner particles. If necessary, a classification step can be performed to remove coarse particles and fine particles contained in the toner particles.

[0108] The obtained toner particles can be used as they are, or the toner can be obtained by mixing the toner particles with an external additive as needed and allowing the additive to adhere to the surface of the toner particles.

[0109] The agitator used for the mixing process is not particularly limited as long as it is a stirring device that can adhere external additives to the surfaces of toner particles, and the external addition process can be performed using an agitator that can mix and stir, such as FM Mixer (trade name, manufactured by Nippon Coke and Engineering Co., Ltd.), Super Mixer (trade name, manufactured by Kawada Manufacturing Co., Ltd.), Q Mixer (trade name, manufactured by Nippon Coke and Engineering Co., Ltd.), Mechanofusion System (trade name, manufactured by Hosokawa Micron Corporation), and Mechano Mill (trade name, manufactured by Okada Seiko Co., Ltd.).

[0110] Examples of external additives include inorganic fine particles such as silica, titanium oxide, aluminum oxide, zinc oxide, tin oxide, calcium carbonate, calcium phosphate, and cerium oxide; and organic fine particles such as polymethyl methacrylate resin, silicone resin, and melamine resin. Among these, inorganic fine particles are preferred, and among inorganic fine particles, silica and titanium oxide are preferred, with silica being more preferred.

[0111] These external additives can be used either alone or in combination of two or more.

[0112] The content of the external additive is preferably 0.05 parts by mass or more and 6 parts by mass or less, and more preferably 0.2 parts by mass or more and 5 parts by mass or less, relative to 100 parts by mass of the toner particles.

[0113] The glass transition temperature (Tg) of the toner is preferably 45.0°C to 65.0°C, and more preferably 50.0°C to 65.0°C.

[0114] When the glass transition temperature of the toner is within the above range, it is possible to achieve both high storage stability and low-temperature fixability. The glass transition temperature can be controlled by the composition of the binder resin, the type of crystalline polyester, and the molecular weight of the binder resin.

[0115] The volume average particle size (Dv) of the toner is preferably 3.00 μm or more and 9.00 μm or less, and more preferably 5.00 μm or more and 8.00 μm or less.

[0116] By setting the volume average particle diameter (Dv) of the toner within the above range, the handleability of the toner can be improved, and dot reproducibility can be fully satisfied.

[0117] Furthermore, the ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) of the toner is preferably 1.25 or less, and more preferably less than 1.25.

[0118] The Dv and Dv / Dn of the toner can be controlled by the amount of dispersant, the type of agitator, the rotation speed, and the like.

[0119] The average circularity of the toner is preferably 0.970 or more, more preferably 0.975 or more. There is no particular upper limit to the average circularity, but it is, for example, 0.995 or less.

[0120] By setting the average circularity within the above range, the toner has good fluidity and can reduce toner deterioration during long-term printing. The average circularity can be controlled by the amount of material used to form the shell layer, the amount of dispersant used, etc.

[0121] The weight-average molecular weight (Mw) of the binder resin is preferably 10,000 to 300,000, more preferably 15,000 to 260,000, and even more preferably 20,000 to 230,000. When the weight-average molecular weight of the binder resin is 300,000 or less, low-temperature fixability tends to be improved. When the weight-average molecular weight of the binder resin (B) is 10,000 or more, heat-resistant storage stability tends to be improved.

[0122] The molecular weight distribution (Mw / Mn) of the binder resin is preferably 2 to 40, more preferably 3 to 35, and even more preferably 3 to 23. When the molecular weight distribution is 40 or less, low-temperature fixability and storage stability tend to be improved. When the molecular weight distribution is 2 or more, hot offset resistance tends to be improved.

[0123] The loss modulus of the toner was measured by dynamic viscoelasticity measurement, and the loss modulus G" at 100°C was 3.0 x 10 5 (dyn / cm 2 ) or less. The loss modulus of the toner is preferably 3.0×10 5 (dyn / cm 2 ) or less, the low-temperature fixability is improved. 5 (dyn / cm 2 ) is as follows.

[0124] Control of the loss modulus can be broadly divided into control of the binder resin and control of the ester compound. With regard to the binder resin, it can be controlled by adjusting the molecular weight and the type of monomer that makes up the binder resin, such as the amount of Unit A and Unit B introduced. With regard to the ester compound, it can be controlled by the content in the toner and the type of ester compound.

[0125] When the toner particle is observed with a scanning transmission electron microscope, domains of compound C are present in the cross section of the toner particle, and the average number of the domains in the cross section is 100 or more, and when the average major axis of the domains is r1 (μm), preferably, r1 is 1.0 μm or less. More preferably, the average number of the domains is 150 or more. Furthermore, more preferably, the average major axis of the domains is 0.5 μm or less.

[0126] When the average number of the domains in the cross section is 100 or more, the contact area of ​​the compound C with the binder resin increases, improving the low-temperature fixability. When the r1 is 1.0 μm or less, the contact area with the binder resin increases, improving the low-temperature fixability.

[0127] The methods for measuring the various physical properties according to the present disclosure are described below.

[0128] <Volume Average Particle Size Dv and Particle Size Distribution Dv / Dn of Toner> The volume average particle diameter Dv, number average particle diameter Dn, and particle size distribution Dv / Dn of the toner are measured using a particle size analyzer (manufactured by Beckman Coulter, Inc., trade name: Multisizer). Measurements using this Multisizer are performed under the following conditions: aperture diameter: 100 μm, dispersion medium: Isoton II (trade name), concentration: 10%, number of particles measured: 100,000.

[0129] Specifically, 0.2 g of toner is placed in a beaker, and an alkylbenzene sulfonic acid aqueous solution (manufactured by Fujifilm Corporation, product name: Drywell) is added as a dispersant. 2 mL of dispersion medium is then added to moisten the toner, after which 10 mL of dispersion medium is added, and the toner is dispersed in an ultrasonic disperser for 1 minute before measurement using the particle size measuring instrument described above.

[0130] <Method for measuring the melting point of wax> 6 to 8 mg of wax is weighed into a sample holder and measured using a differential scanning calorimeter (Seiko Instruments Inc., product name: RDC-220) under conditions of heating from -200°C to 1,000°C at a rate of 100°C / min to obtain a DSC curve. The peak temperature of the endothermic peak in the DSC curve is taken as the melting point.

[0131] <Method for measuring the glass transition temperature of toner or macromonomer> The glass transition temperature of the toner or macromonomer is measured in accordance with ASTM D3418-97.

[0132] Specifically, 10 mg of the toner obtained by drying is weighed out and placed in an aluminum pan. An empty aluminum pan is used as a reference. The glass transition temperature of the weighed toner or macromonomer is measured using a differential scanning calorimeter (manufactured by SII NanoTechnology, Inc., product name: DSC6220) in accordance with ASTM D 3418-97 at a temperature range of 0°C to 150°C and a heating rate of 10°C / min.

[0133] <Method for measuring weight average molecular weight (Mw) and peak molecular weight (Mp) of resins, etc.> The weight average molecular weight (Mw) and peak molecular weight (Mp) of a resin are measured using gel permeation chromatography (GPC) as follows.

[0134] (1) Preparation of measurement samples The sample and tetrahydrofuran (THF) are mixed at a concentration of 5.0 mg / mL, left at room temperature for 5 to 6 hours, and then shaken thoroughly to thoroughly mix the THF and sample until the sample no longer combines. The mixture is then left at room temperature for at least 12 hours. The time from the start of mixing the sample and THF to the end of the standing period is set at at least 72 hours, and the tetrahydrofuran (THF)-soluble portion of the sample is obtained.

[0135] Thereafter, the solution is filtered through a solvent-resistant membrane filter (pore size 0.45 μm to 0.50 μm, Myshoridisc H-25-2 [manufactured by Tosoh Corporation]) to obtain a sample solution.

[0136] (2) Measurement of the sample Using the obtained sample solution, measurements are carried out under the following conditions. Apparatus: High-speed GPC apparatus LC-GPC 150C (Waters) Column: Shodex GPC KF-801, 802, 803, 804, 805, 806, 807 (Showa Denko Co., Ltd.) in 7-unit series Mobile phase: THF Flow rate: 1.0mL / min Column temperature: 40℃ Sample injection volume: 100 μL Detector: RI (refractive index) detector

[0137] When measuring the molecular weight of a sample, the molecular weight distribution of the sample is calculated from the relationship between the logarithm of the calibration curve prepared using several monodisperse polystyrene standard samples and the count number.

[0138] The standard polystyrene samples used to create the calibration curve were those manufactured by Pressure Chemical Co. or Toyo Soda Kogyo Co., Ltd., with a molecular weight of 6.0 × 10 2 , 2.1×10 3 , 4.0×10 3 , 1.75×10 4 , 5.1×10 4 , 1.1×10 5 , 3.9 × 10 5 , 8.6×10 5 , 2.0×10 6 , 4.48×10 6 Use the following.

[0139] <Method for measuring the area occupied by wax domains in a toner cross section using a transmission electron microscope> Cross-sectional observation of the toner using a transmission electron microscope (TEM) and evaluation of the wax domains are carried out as follows.

[0140] Ruthenium dyeing of the toner cross section provides a clear contrast between crystalline materials, which are dyed less strongly than amorphous materials. This is thought to be because the dye penetrates less deeply into crystalline materials than amorphous materials due to differences in density.

[0141] The amount of ruthenium atoms varies depending on the strength of the staining, so areas that are strongly stained have many ruthenium atoms, making it difficult for the electron beam to penetrate, and appear black in the image.On the other hand, areas that are weakly stained have few ruthenium atoms, making it easy for the electron beam to penetrate, and appear white in the image.

[0142] Using an osmium plasma coater (Filgen, OPC80T), a protective film of osmium (5 nm) and a naphthalene film (20 nm) were applied to the toner, which was then embedded in photocurable resin D800 (JEOL). A toner cross section with a thickness of 60 nm was then prepared using an ultrasonic ultramicrotome (Leica, UC7) at a cutting speed of 1 mm / s.

[0143] The obtained cross section is stained for 15 minutes in a 500 Pa atmosphere of RuO4 gas using a vacuum electron staining device (VSC4R1H, Filgen), and then subjected to STEM observation using the STEM mode of a TEM (JEOL, JEM2800).

[0144] The STEM probe size is 1 nm, and the image size is acquired at 1024 pixels x 1024 pixels.

[0145] The obtained images are binarized (threshold 120 / 255 levels) using the image processing software "Image-Pro Plus (Media Cybernetics)". By binarizing, the crystalline domains can be extracted.

[0146] <Method for calculating the average number of domains of ester compounds and the average major axis r1 (μm) of domains of ester compounds> Using the toner cross-section observation method described above, 50 toner particles within ±2.0 μm of the weight average particle diameter were randomly selected and photographed to obtain cross-sectional images. Compared to amorphous resins and magnetic materials, crystalline materials are less susceptible to Ru staining, and appear white to gray in the cross-sectional images.

[0147] The average number of domains of the ester compound is determined by counting the number of domains with a major axis of 20 nm or more in the above-mentioned 50 toner cross-sectional images, and the average value among the 50 toner particles is taken as the average number of domains of the ester compound.

[0148] Furthermore, the average major axis r1 (μm) of the ester compound domains is measured by randomly selecting 10 cross sections from the above-mentioned toner cross-sectional image, then randomly selecting 100 domains of the ester compound from the 10 cross sections, and measuring the major axis. The average value of these is taken as the average major axis r1 (μm) of the ester compound domains in the toner cross section.

[0149] <Method for measuring average circularity of toner> The average circularity of the toner is measured using a flow particle image analyzer "FPIA-3000" (manufactured by Sysmex Corporation) under the measurement and analysis conditions used during the calibration process.

[0150] The specific measurement method is as follows.

[0151] First, about 20 mL of ion-exchanged water, from which impurities such as solids have been removed, is placed in a glass container. About 0.2 mL of a solution prepared by diluting Contaminon N (a 10% aqueous solution of a pH 7 neutral detergent for cleaning precision measuring instruments, consisting of a nonionic surfactant, anionic surfactant, and organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) approximately three times by mass with ion-exchanged water is added as a dispersant.

[0152] Approximately 0.02 g of the sample to be measured was then added and dispersed for 2 minutes using an ultrasonic disperser to obtain a dispersion for measurement. The dispersion was then cooled appropriately so that the temperature was between 10°C and 40°C. A tabletop ultrasonic cleaner disperser "VS-150" (manufactured by Vervoclear) with an oscillation frequency of 50 kHz and an electrical output of 150 W was used as the ultrasonic disperser. A predetermined amount of ion-exchanged water was placed in the water tank, and approximately 2 mL of Contaminon N was added to the water tank.

[0153] For the measurement, the flow particle image analyzer described above equipped with the "LUCPLFLN" objective lens (magnification 20x, numerical aperture 0.40) was used, and the particle sheath "PSE-900A" (manufactured by Sysmex Corporation) was used as the sheath liquid. The dispersion prepared according to the above procedure was introduced into the flow particle image analyzer, and 2,000 magnetic toner particles were counted in HPF measurement mode and total count mode. The average circularity of the toner was calculated from the results.

[0154] The secondary ion intensity at the outermost surface of the toner (ie, at t=0) is the value of secondary ion mass / secondary ion charge number (m / z) measured without sputtering the toner.

[0155] <Measurement of dynamic viscoelasticity of toner> The measuring device used is a rotating plate type rheometer "ARES" (manufactured by TA INSTRUMENTS).

[0156] The measurement sample is prepared by press-molding the toner into a disk shape with a diameter of 7.9 mm and a thickness of 2.0±0.3 mm using a tablet press in an environment of 25° C.

[0157] The sample is attached to a parallel plate, and the temperature is raised from room temperature (25°C) to the measurement start temperature for viscoelasticity (50°C), and measurement is started under the following conditions.

[0158] The measurement conditions are as follows: (1) Set the sample so that the initial normal force is 0. (2) Use parallel plates with a diameter of 7.9 mm. (3) The frequency is 1.0 Hz. (4) The initial applied strain (Strain) is set to 0.1%. (5) Measurements are performed between 50°C and 160°C at a temperature ramp rate of 2.0°C / min and a sampling frequency of 1 time / °C.

[0159] The measurements are performed under the following automatic adjustment mode settings.

[0160] Measurements are performed in the Auto Strain mode. (6) Set the maximum applied strain to 20.0%. (7) Set the maximum torque (Max Allowed Torque) to 200.0 g·cm and the minimum torque (Min Allowed Torque) to 0.2 g·cm. (8) Set the strain adjustment to 20.0% of the current strain. The measurement is performed in the auto tension adjustment mode. (9) Set Auto Tension Direction to Compression. (10) Set the initial static force to 10.0 g and the auto tension sensitivity to 40.0 g. (11) The operating condition for the auto tension is that the sample modulus is 1.0 x 103 (Pa) or more.

[0161] From the loss modulus G" value at 100°C in this measurement, the loss modulus G" (dyn / cm) at 100°C in the dynamic viscoelasticity measurement 2 ) is found. [Example]

[0162] The present disclosure will be specifically described below with reference to examples, but the present disclosure is not limited to these examples. Note that the number of parts in the examples is based on mass unless otherwise specified.

[0163] <Method of producing ester compound C1> Into a reaction vessel equipped with a thermometer, a nitrogen inlet tube, a stirrer, a Dean-Stark trap, and a Dimroth condenser, 100 parts of behenyl alcohol as an alcohol monomer and 80 parts of stearic acid as a carboxylic acid monomer were added, and an esterification reaction was carried out at 200°C for 15 hours.

[0164] To the resulting ester compound, 20 parts of toluene and 25 parts of isopropanol were added, and 190 parts of a 10% aqueous potassium hydroxide solution, in an amount equivalent to 1.5 times the acid value of the ester compound, was added, followed by stirring at 70°C for 4 hours. The water tank was then removed. 20 parts of ion-exchanged water was then added, followed by stirring at 70°C for 1 hour, after which the water tank was removed and washed. The above washing process was repeated until the pH of the removed water tank became neutral.

[0165] The solvent was then removed under reduced pressure at 200°C and 1 kPa to obtain the final product, behenyl stearate (ester compound C1), an ester compound of behenyl alcohol and stearic acid. The physical properties of the obtained ester compound C1 are shown in Table 1.

[0166] <Method of Producing Ester Compounds C2 to C4> Ester compounds C2 to C5 were obtained in the same manner as in the production method of ester compound C1, except that the monomers were changed as shown in Table 1. Table 1 shows the physical properties of the obtained ester compounds C2 to C5.

[0167] [Table 1]

[0168] <Macromonomer> The monomers listed in Table 2 were prepared as macromonomers that serve as precursors of the macromonomer-derived units to be contained in the styrene-acrylic resin in the binder resin.

[0169] [Table 2]

[0170] <Method for producing decyl acrylate> 288 g of acrylic acid, 160 g of decanol, 0.2 g of copper chloride, 0.14 g of hydroquinone monomethyl ether as a polymerization inhibitor, and 300 g of toluene were mixed in a reaction vessel equipped with a thermometer, a nitrogen inlet tube, a stirrer, a Dean-Stark trap, and a Dimroth condenser, and an esterification reaction was carried out for 10 hours at a reaction temperature of about 80°C while removing condensed water.

[0171] 100 parts of isopropanol was added, and 190 parts of a 10% aqueous potassium hydroxide solution was added, followed by stirring at 70°C for 4 hours. The aqueous layer was then removed. 20 parts of ion-exchanged water was added, followed by stirring at 70°C for 1 hour, after which the aqueous layer was removed and washing was carried out. The above washing process was repeated until the pH of the removed aqueous layer became neutral.

[0172] Thereafter, the solvent was removed under reduced pressure at 70°C and 1 kPa to obtain the final target product, decyl acrylate (b3).

[0173] <Long-chain alkyl monomer> The monomers listed in Table 3 were prepared as precursors of the units derived from long-chain alkyl monomers to be contained in the styrene-acrylic resin in the binder resin.

[0174] [Table 3]

[0175] <Method of manufacturing styrene-acrylic resin 1> 74 parts styrene 26 parts n-butyl acrylate Lauryl acrylate (b1) 8 parts Macromonomer a1: 0.25 parts of polymethacrylate macromonomer (manufactured by Toagosei Chemical Industry Co., Ltd., product name: AA6, Tg = 94°C) 200.0 parts toluene Polymerization initiator: azobisisobutyronitrile (AIBN) 0.16 parts The above mixture was placed in a reaction vessel equipped with a stirrer and a thermometer while the atmosphere was replaced with nitrogen. After heating to 65°C, polymerization was carried out for 5 hours. After cooling to room temperature, the toluene solvent was distilled off to obtain styrene-acrylic resin 1 (binder resin for toner 13).

[0176] <Method of manufacturing toner 1> Polymerizable monomers: 74 parts styrene, 26 parts n-butyl acrylate Lauryl acrylate (b1) 8 parts Colorant: Carbon black (Mitsubishi Chemical, product name: #25B) 7 parts Crosslinking agent: 0.74 parts divinylbenzene Charge control agent: 0.37 parts styrene / acrylic resin (manufactured by Fujikura Kasei Co., Ltd., product name: FCA-592P) Molecular weight regulator: 1 part tetraethyl thiuram disulfide Macromonomer a1: 0.25 parts of polymethacrylate macromonomer (manufactured by Toagosei Chemical Industry Co., Ltd., product name: AA6, Tg = 94°C) The above materials were stirred and mixed using a conventional stirring device, then uniformly dispersed using a media-type disperser and heated to 63°C.

[0177] To this, 20 parts of ester compound C1 was added, mixed, and dissolved to obtain a polymerizable monomer composition.

[0178] On the other hand, in a stirring tank at room temperature, an aqueous solution prepared by dissolving 7.4 parts of magnesium chloride in 250 parts of ion-exchanged water was gradually added with stirring to prepare a magnesium hydroxide colloidal dispersion (3.0 parts of magnesium hydroxide).

[0179] The polymerizable monomer composition was added to the magnesium hydroxide colloidal dispersion obtained above at room temperature, the temperature was raised to 60°C, and the mixture was stirred until the droplets were stabilized. Five parts of t-butylperoxy-2-ethylhexanoate (manufactured by NOF Corporation, trade name: Perbutyl O) was added as a polymerization initiator, and then the mixture was stirred at a high shear rate of 15,000 rpm using an in-line emulsifying disperser (manufactured by Pacific Machinery Works, trade name: Milder) to form droplets of the polymerizable monomer composition.

[0180] The magnesium hydroxide colloidal dispersion containing droplets of the polymerizable monomer composition was placed in a reactor equipped with a stirring blade. The temperature was raised to 89°C and maintained constant, allowing for polymerization. Next, when the polymerization conversion reached 98%, the system temperature was cooled to 75°C. 15 minutes after reaching 75°C, 3 parts of methyl methacrylate as a shell polymerizable monomer and 0.36 parts of 2,2'-azobis[2-methyl-N-(1,1-bis(hydroxymethyl)2-hydroxyethyl)propionamide] tetrahydrate (manufactured by Wako Pure Chemical Industries, Ltd., trade name: VA086) dissolved in 10 parts of ion-exchanged water were added. After continuing the polymerization for another 3 hours, the reaction was stopped, yielding an aqueous dispersion of colored resin particles with a pH of 9.5.

[0181] After this, the aqueous dispersion of colored resin particles was heated to 90°C and passed through a nitrogen gas flow rate of 0.6 m 3 The suspension was stripped at 100°C / hr·kg for 5 hours. The suspension was then cooled from 98.0°C to 30°C at a rate of 100°C / min, then heated to 50°C and held there for 6 hours. The suspension was then cooled naturally to 25°C at room temperature at a cooling rate of 1°C / min. The resulting aqueous dispersion was then acid washed with sulfuric acid while stirring to a pH of 6.5 or less. The water was then separated by filtration, and 500 parts of ion-exchanged water was added to re-slurry the suspension and washed with water. The dehydration and washing were then repeated several times. The solids were then filtered and separated, then placed in a dryer and dried at 40°C for 12 hours to obtain toner particles 1.

[0182] To the toner particles 1 (100 parts) obtained above, 0.7 parts of hydrophobicized silica fine particles having a number average primary particle size of 7 nm and 1 part of hydrophobicized silica fine particles having a number average primary particle size of 50 nm were added and mixed using a high-speed mixer (manufactured by Nippon Coke & Engineering Co., Ltd., product name: FM Mixer) to produce toner 1. The physical properties of the obtained toner 1 are shown in Tables 5 and 6.

[0183] <Method of manufacturing toners 2 to 12 and 14 to 21> Toners 2 to 12 and 14 to 21 were produced in the same manner as Toner 1, except that the toner composition and toner production method were changed as shown in Table 4. The physical properties of Toners 2 to 12 and 14 to 21 are shown in Tables 5 and 6.

[0184] <Method of manufacturing toner 13> The following materials were mixed for 4 minutes using an FM mixer ("FM-20" manufactured by Nippon Coke and Engineering Co., Ltd.) at a rotation speed of 2000 rpm. Binder resin: styrene-acrylic resin 1 90 parts Charge control agent: styrene / acrylic resin ("FCA-207P" manufactured by Fujikura Kasei Co., Ltd.) 3 parts Colorant: Carbon black (Mitsubishi Chemical, product name: #25B) 4 parts Ester compound C1 3 parts The resulting mixture was melt-kneaded in a twin-screw extruder ("PCM-30" manufactured by Ikegai Corporation) under conditions of a melt-kneading temperature (cylinder temperature) of 120°C, a rotation speed of 150 rpm, and a processing speed of 100 g / min. The resulting melt-kneaded product was coarsely pulverized to approximately 2 mm using a Rotoplex pulverizer (manufactured by Alpine Co., Ltd.) and then pulverized using a mechanical pulverizer ("Turbo Mill T250" manufactured by Freund-Turbo Corporation). The pulverized product was classified using an air classifier ("EJ-L3" manufactured by Nittetsu Mining Co., Ltd.) to obtain toner particles 13 with an average particle size of 8.5 μm.

[0185] The obtained toner particles 13 (100 parts), 0.8 parts of silica microparticles ("RA200" manufactured by Nippon Aerosil Co., Ltd.), and 0.8 parts of titanium oxide ("EC100" manufactured by Titanium Kogyo Co., Ltd.) were mixed for 5 minutes in an FM mixer ("FM-20" manufactured by Nippon Coke and Engineering Co., Ltd.) at a rotation speed of 2000 rpm to obtain toner 13.

[0186] The physical properties of Toner 13 are shown in Tables 5 and 6.

[0187] [Table 4]

[0188] [Table 5]

[0189] [Table 6]

[0190] Example 1 The following evaluations were carried out on Toner 1. The evaluation results are shown in Table 7.

[0191] [Rating 1: Gloss unevenness] The evaluation of gloss unevenness was carried out in a low-temperature, low-humidity environment (temperature 15°C, humidity 5% RH) using a HL-5470DW (monochrome laser printer manufactured by Brother Industries) and a cartridge with the paper dust collection roller removed. The paper used was rough FOX RIVER BOND paper (110 g / m 2 ) and printed a solid black image with a printing ratio of 100%.

[0192] The gloss was measured using a handheld gloss meter PG-1 (manufactured by Nippon Denshoku Industries Co., Ltd.). The projection angle and reception angle were both set to 75° for the measurement. The image gloss was measured at 10 points randomly selected from the printed image, and the gloss unevenness was evaluated based on the difference between the highest and lowest gloss values. The evaluation criteria were as follows: A: The gross difference is less than 2.00%. B: The gross difference is 2.00% or more and less than 3.00%. C: The gloss difference is 3.00% or more and less than 5.00%. D: Gross difference is 5.00% or more.

[0193] [Evaluation 2: Toner Deterioration Evaluation] The evaluation procedure involved using an HL-5470DW (Brother Industries monochrome laser printer) and a cartridge with the paper dust collection roller removed, leaving the toner together with the image forming device in a high-temperature, high-humidity environment (temperature 32.5°C, humidity 80% RH) for one day, and then printing 15,000 sheets of horizontal line images with a printing rate of 1% in intermittent mode under the above environment, and then printing three solid images. For image quality evaluation, the density of the four corners of the last three solid images was measured using a Macbeth reflection densitometer, and these 12 values ​​were evaluated according to the following criteria. A: The difference between the maximum and minimum image density values ​​is less than 0.10 B: The difference between the maximum and minimum image density values ​​is 0.10 or more and less than 0.20 C: The difference between the maximum and minimum image density values ​​is 0.20 or more and less than 0.25 D: The difference between the maximum and minimum image density values ​​is 0.25 or more

[0194] [Evaluation 3: Evaluation of low-temperature fixability] The evaluation of low-temperature fixability was carried out in a low-temperature, low-humidity environment (temperature 15°C, humidity 5% RH) using an HL-5470DW (monochrome laser printer manufactured by Brother Industries) and a cartridge with the paper dust collection roller removed. The image forming apparatus was modified so that the fixing temperature of the fixing unit could be set as desired.

[0195] Using this device, the fixing temperature of the fixing unit was adjusted in 5°C increments within the range of 180°C to 230°C, and the image was printed on rough FOX RIVER BOND paper (110 g / m 2 A solid black image with a printing ratio of 100% was output using a printer. The presence or absence of white spots in the solid image was visually evaluated, and the lowest temperature at which white spots appeared was used to evaluate the low-temperature fixability. A: White spots occurred at temperatures below 200°C. B: White spots occurred at temperatures between 200°C and 210°C. C: White spots occurred at temperatures between 210°C and 220°C. D: White spots occurred at 220°C or higher.

[0196] [Evaluation 4: Evaluation of storage stability] The storage stability was evaluated according to the following procedure.

[0197] Using a HL-5470DW (Brother Industries monochrome laser printer) and a cartridge with the paper dust collection roller removed, one solid image was printed in a room temperature and humidity environment (temperature 25.0°C, relative humidity 60%), and then stored with the developing device in a harsh environment (temperature 40.0°C, relative humidity 95%) for 40 days. After storage, one solid image was printed in a room temperature and humidity environment (temperature 25.0°C, relative humidity 60%), and the image density before and after storage was compared and evaluated. The density of the solid image was measured using a Macbeth reflection densitometer (Macbeth). A: The density difference is less than 0.05 B: Density difference is 0.05 or more and less than 0.10 C: Density difference is 0.10 or more and less than 0.20 D: Density difference is 0.20 or more

[0198] [Examples 2 to 15, Comparative Examples 1 to 5] Examples 2 to 15 and Comparative Examples 1 to 5 were evaluated in the same manner as in Example 1, except that the combination of toner and photoreceptor was changed as shown in Table 5. Table 7 shows the evaluation results.

[0199] [Table 7]

Claims

1. A toner having toner particles having a binder resin and an ester compound (excluding polymers), the binder resin contains a styrene-acrylic resin having a unit derived from a macromonomer and a monomer unit represented by the following formula (1), 【Chemistry 1】 (In formula (1), R 1 represents a hydrogen atom or a methyl group, and R 2 represents a linear alkyl group having 10 to 14 carbon atoms. the ester compound is at least one ester compound selected from the group consisting of an ester compound represented by the following formula (2), an ester compound represented by the following formula (3), and an ester compound represented by the following formula (4), 【Chemistry 2】 (In formula (2), formula (3) and formula (4), R 31 and R 41 each independently represents an alkylene group having 2 to 8 carbon atoms; R 32 , R 33 , R 42 , R 43 , R 51 and R 52 each independently represents a linear alkyl group having 14 to 24 carbon atoms. The SP value of the macromonomer-derived unit is SPa (J / cm 3 ) 1 / 2 The SP value of the monomer unit represented by formula (1) is SPb (J / cm 3 ) 1 / 2 The SP value of the ester compound is SPc (J / cm 3 ) 1 / 2 When The SPa is 19.50 or more and 20.50 or less, The toner is characterized in that the SPa, SPb, and SPc satisfy the following relational formula (a), the following relational formula (b), and the following relational formula (c). SPa-SPb≦2.0 (a) SPb-SPc≦1.5 (b) SPa-SPc≧2.0 (c)

2. 2. The toner according to claim 1, wherein the styrene-acrylic resin contains 1% by mass or more and 15% by mass or less of the unit represented by formula (1).

3. 3. The toner according to claim 1, wherein the unit represented by formula (1) is a unit represented by the following formula (1'): 【Transformation 3】 (In formula (1'), R 1 represents a hydrogen atom or a methyl group, and R 2 represents a linear alkyl group having 12 carbon atoms.

4. 4. The toner according to claim 1, wherein the styrene-acrylic resin has a sulfide group.

5. The loss modulus G″ at 100° C. in the dynamic viscoelasticity measurement of the toner is 3.0×10 5 (dyn / cm 2 5. The toner according to claim 1, wherein the toner has a particle size of 0.1 or less.

6. 6. The toner according to claim 1, wherein the macromonomer has a unit represented by the following formula (3) in the main chain portion of the macromonomer: 【Chemistry 4】 (Equation (3) is R 1 and R 2 indicates a methyl group.)

7. 7. The toner according to claim 1, wherein the average circularity of the toner is 0.975 or more and 0.995 or less.

8. a domain of the ester compound is present in a cross section of the toner particle observed with a scanning transmission electron microscope, the average number of the domains in the cross section is 100 or more; When the average major axis of the domain is r1 (μm), r1 is 1.0 μm or less. The toner according to any one of claims 1 to 7.

9. 9. The toner according to claim 1, wherein the macromonomer that is a precursor of the macromonomer-derived unit has a glass transition temperature of 60° C. or higher.

10. 10. The toner according to claim 1, wherein the macromonomer that is a precursor of the macromonomer-derived unit has a number average molecular weight of 5,000 or more.

Images