Toner for electrostatic image development, electrostatic image developer, toner cartridge, process cartridge, image forming apparatus, and image forming method.

Abstract

To provide a toner for electrostatic charge image development that reduces the difference in glossiness between a fixed image in a low temperature and low pressure condition and a fixed image in a high temperature and high pressure condition, while allowing acquisition of good fixability.SOLUTION: A toner for electrostatic charge image development includes toner particles containing a binder resin. In dynamic viscoelasticity measurement, when the loss tangent tanδ at a temperature of 90°C and a strain amount of 1% is defined as D1(90), the loss tangent tanδ at a temperature of 90°C and a strain amount of 50% as D50(90), the loss tangent tanδ at a temperature of 150°C and a strain amount of 1% as D1(150), and the loss tangent tanδ at a temperature of 150°C and a strain amount of 50% as D50(150), D1(90), D50(90), D1(150), and D50(150) are each 0.5 or more and 2.5 or less, the value of D50(150)-D1(150) is less than 1.5, and the value of D50(90)-D1(90) is less than 1.0. The toner particles further contain resin particles. The number average molecular weight of a THF soluble matter in the toner particles is 5000 or more and 15000 or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a toner for electrostatic image development, an electrostatic image developer, a toner cartridge, a process cartridge, an image forming apparatus, and an image forming method. [Background technology]

[0002] Patent Document 1 discloses an electrostatic latent image developing toner containing toner particles containing a binder resin, wherein the binder resin contains an amorphous resin and a crystalline resin, and when dynamic viscoelastic strain dispersion measurement is performed under conditions of a temperature of 130°C, a frequency of 1 Hz, and a strain amplitude of 1.0 to 500%, and the integral value of the stress in the stress-strain curve at a strain amplitude of 100% is defined as S130 and the slope of the major axis as θ130, S130 is greater than 0 Pa and less than or equal to 350,000 Pa, and θ130 is greater than 22° and less than 90°.

[0003] Patent Document 2 discloses a toner for developing electrostatic images, comprising at least a binder resin and a release agent, wherein the binder resin comprises at least a crystalline resin, and the toner is characterized in that the storage modulus of elasticity, measured at a frequency of 1 Hz and 150°C with strain varying from 0.01% to 1000%, satisfies a specific relationship.

[0004] Patent Document 3 discloses an electrostatic latent image developing toner containing toner particles containing a binder resin, wherein the binder resin contains an amorphous vinyl resin and a crystalline resin, and when dynamic viscoelastic strain dispersion measurement is performed under conditions of a temperature of 130°C, a frequency of 1Hz, and a strain amplitude of 1.0 to 500%, and the integral value of the stress in the stress-strain curve at a strain amplitude of 100% is defined as S130 and the slope of the major axis as θ130, S130 is greater than 0 Pa and less than or equal to 350,000 Pa, and θ130 is greater than or equal to 0° and less than 10°.

[0005] Patent Document 4 discloses an electrostatic charge image developing toner containing at least toner base particles containing a binder resin and a release agent, and an external additive, wherein the binder resin contains at least a crystalline resin, and in the electrostatic charge image developing toner, the value tanδ6℃ / min of the peak top of the loss tangent measured from 25°C to 100°C under the conditions of a frequency of 1 Hz and a temperature rising rate of 6°C / min, and the value tanδ3℃ / min of the peak top of the loss tangent measured from 25°C to 100°C under the conditions of a frequency of 1 Hz and a temperature rising rate of 3°C / min satisfy a specific relationship.

[0006] Patent Document 5 discloses an electrostatic charge image developing toner containing at least a binder resin, a colorant, and a release agent, and for these toners, the change rate γG’ of the storage elastic modulus G’ is 50% < γG’ < 86%, and the change rate γG” of the loss elastic modulus G” is greater than 50%, and the storage elastic modulus G’ of the toner in the range of 1 to 50% strain at a temperature of 150°C is 5×10 2 ~3.5×10 3 Pa·s, and the binder resin includes an amorphous resin and a crystalline resin.

[0007] Patent Documents 6 and 7 disclose an electrostatic charge image developing toner composed of toner particles containing a binder resin. In the elastic image obtained by an atomic force microscope (AFM) of the cross-section of the toner particles, the binder resin has a domain-matrix structure composed of a high-elasticity resin constituting the domain and a low-elasticity resin constituting the matrix, and the arithmetic mean value of the ratio (L / W) of the major axis L to the minor axis W of each domain is within the range of 1.5 to 5.0, and domains with the major axis L within the range of 60 to 500 nm are present at 80% or more, and domains with the minor axis W within the range of 45 to 100 nm are present at 80% or more. This is the electrostatic charge image developing toner characterized by the above.

Prior Art Documents

Patent Documents

[0008] [Patent Document 1] Japanese Patent Publication No. 2020-042122 [Patent Document 2] Japanese Patent Publication No. 2020-106685 [Patent Document 3] Japanese Patent Publication No. 2020-042121 [Patent Document 4] Japanese Patent Publication No. 2019-144368 [Patent Document 5] Japanese Patent Publication No. 2013-160886 [Patent Document 6] Japanese Patent Publication No. 2011-237793 [Patent Document 7] Japanese Patent Publication No. 2011-237792 [Overview of the project] [Problems that the invention aims to solve]

[0009] In image formation using electrostatic image developing toner, for example, the toner image transferred to the recording medium is fixed to the recording medium by heating and pressurizing. Here, if an electrostatic image developing toner containing toner particles that melt easily when heated is used to obtain good fixation, the difference in gloss between the fixed image fixed under high temperature and high pressure conditions and the fixed image fixed under low temperature and low pressure conditions may become large.

[0010] The object of the present invention is to provide a toner for electrostatic image development that provides good fixability while having a small difference in gloss between the image fixed under low temperature and low pressure conditions and the image fixed under high temperature and high pressure conditions, compared to cases where any of D1(90), D50(90), D1(150), and D50(150) is less than 0.5 or greater than 2.5, where the value of D50(150)-D1(150) is 1.5 or greater, where the toner particles do not contain resin particles, or where the number average molecular weight of the tetrahydrofuran soluble components in the toner particles is less than 5000 or greater than 15000. [Means for solving the problem]

[0011] The above problems will be solved by the following means:

[0012] <1> A toner for developing electrostatic images, comprising toner particles containing a binder resin, In the dynamic viscoelasticity measurement of the electrostatic image developing toner, when the loss tangent tanδ at a temperature of 90°C and a strain of 1% is D1(90), the loss tangent tanδ at a temperature of 90°C and a strain of 50% is D50(90), the loss tangent tanδ at a temperature of 150°C and a strain of 1% is D1(150), and the loss tangent tanδ at a temperature of 150°C and a strain of 50% is D50(150), D1(90), D50(90), D1(150), and D50(150) are each between 0.5 and 2.5. The value of D50(150)-D1(150) is less than 1.5. The value of D50(90)-D1(90) is less than 1.0. The toner particles further contain resin particles, A toner for developing electrostatic images, wherein the number-average molecular weight of the tetrahydrofuran-soluble components in the toner particles is 5,000 or more and 15,000 or less.

[0013] <2> The glass transition temperature Tg, determined from the dynamic viscoelasticity measurement of the resin particles, is between 10°C and 45°C. <1> Toner for developing electrostatic images as described above. <3> In the dynamic viscoelasticity measurement of the resin particles during a temperature increase of 2°C / min, the loss tangent tanδ in the range of 30°C to 150°C is 0.01 to 2.5. <1> or <2> Toner for developing electrostatic images as described above. <4> The number-average particle size of the aforementioned resin particles is between 60 nm and 300 nm. <1> ~ <3> A toner for developing electrostatic images, as described in one of the following. <5> The content of the aforementioned resin particles is 2% by mass or more and 30% by mass or less relative to the total amount of toner particles. <1> ~ <4> A toner for developing electrostatic images, as described in one of the following.

[0014] <6> The aforementioned resin particles are crosslinked resin particles. <1> ~ <5> A toner for developing electrostatic images, as described in one of the following. <7> The aforementioned crosslinked resin particles are styrene (meth)acrylic resin particles. <6> Toner for developing electrostatic images as described above. <8> The difference between the solubility parameter SP value (S) of the resin particles and the solubility parameter SP value (R) of the binder resin (SP value (S) - SP value (R)) is between -0.32 and -0.12. <1> ~ <7> A toner for developing electrostatic images, as described in one of the following.

[0015] <9> In a dynamic viscoelasticity measurement of the component obtained by removing the resin particles from the toner particles during a temperature increase of 2°C / min, the storage modulus G' in the range of 30°C to 50°C is 1 × 10⁻⁶. 8 The Pa value is greater than or equal to the storage modulus G' of 1 × 10⁻⁶. 5 The temperature at which it reaches below Pa is between 65°C and 90°C. <1> ~ <8> A toner for developing electrostatic images, as described in one of the following. <10> In a dynamic viscoelasticity measurement of the component obtained by removing the resin particles from the toner particles during a temperature increase of 2°C / min, the storage modulus G' was 1 × 10⁻⁶. 5 The loss tangent tanδ at temperatures below Pa is between 0.8 and 1.6. <9> Toner for developing electrostatic images as described above.

[0016] <11> In dynamic viscoelasticity measurements during a 2°C / min temperature increase, when the storage modulus of the resin particles is G'(p90-150), the storage modulus of the toner particles is G'(t90-150), and the storage modulus of the component obtained by removing the resin particles from the toner particles is G'(r90-150), then 1 × 10⁻¹⁰ 4 Pa≦G'(p90-150)≦1×10 6The toner for electrostatic charge image development according to any one of <1> to <10>, wherein Pa and 1.0 ≦ logG’(t90-150) - logG’(r90-150) ≦ 4.0. <12> In the dynamic viscoelasticity measurement of the toner for electrostatic charge image development during temperature increase at 2 °C / min, the storage elastic modulus G’ in the range of 30 °C or higher and 50 °C or lower is 1×10 8 Pa or more, and the temperature at which the storage elastic modulus G’ reaches less than 1×10 5 Pa is 65 °C or higher and 90 °C or lower, the toner for electrostatic charge image development according to any one of <1> to <11>.

[0017] <13> The binder resin contains a crystalline resin, The content of the crystalline resin is 4% by mass or more and 50% by mass or less with respect to the entire binder resin, the toner for electrostatic charge image development according to any one of <1> to <12>. <14> The binder resin contains a polyester resin, the toner for electrostatic charge image development according to any one of <1> to <13>. [[ID=二十一]] <15> The binder resin includes an amorphous polyester resin having an aliphatic dicarboxylic acid unit and a crystalline polyester resin having an aliphatic dicarboxylic acid unit, the toner for electrostatic charge image development according to <14>. <16> The resin particles have a bifunctional alkyl acrylate as a structural unit, and the number of carbon atoms in the alkylene chain in the bifunctional alkyl acrylate is 6 or more, the toner for electrostatic charge image development according to any one of <1> to <15>.

[0018] <17> An electrostatic charge image developer containing the toner for electrostatic charge image development according to any one of <1> to <16>. <18> Accommodating the toner for electrostatic charge image development according to any one of <1> to <16>, A toner cartridge that is detachable from an image forming apparatus. <19> <17> The development means contains the electrostatic image developer described above, and develops the electrostatic image formed on the surface of the image holder as a toner image using the electrostatic image developer, A process cartridge that is attached to and detached from an image forming apparatus. <20> Image holder and, A charging means for charging the surface of the image holder, A means for forming an electrostatic image on the surface of the charged image holder, <17> A developing means containing the electrostatic image developer described above, and developing the electrostatic image formed on the surface of the image holder as a toner image using the electrostatic image developer, A transfer means for transferring a toner image formed on the surface of the image holder to the surface of a recording medium, Fixing means for fixing the toner image transferred to the surface of the recording medium, An image forming apparatus equipped with the following features. <21> A charging step in which the surface of the image holder is charged, A step of forming an electrostatic image on the surface of the charged image holder, <17> A developing step in which the electrostatic image formed on the surface of the image holder is developed as a toner image using the electrostatic image developer described above, A transfer step of transferring the toner image formed on the surface of the image holder to the surface of the recording medium, A fixing step for fixing the toner image transferred to the surface of the recording medium, An image forming method having the following characteristics. [Effects of the Invention]

[0019] <1> According to the invention, compared to cases where any of D1(90), D50(90), D1(150), and D50(150) is less than 0.5 or greater than 2.5, where the value of D50(150)-D1(150) is 1.5 or greater, or where the value of D50(90)-D1(90) is 1.0 or greater, where the toner particles do not contain resin particles, or where the number average molecular weight of the tetrahydrofuran soluble components in the toner particles is less than 5000 or greater than 15000, a toner for electrostatic image development is provided that achieves good fixation while having a small difference in gloss between the image fixed under low temperature and low pressure conditions and the image fixed under high temperature and high pressure conditions.

[0020] <2> According to the invention, compared to cases where the glass transition temperature Tg, determined from dynamic viscoelasticity measurement of resin particles, is less than 10°C or more than 45°C, a toner for developing electrostatic images is provided that achieves good fixability while having a small difference in gloss between the image fixed under low temperature and low pressure conditions and the image fixed under high temperature and high pressure conditions. <3> According to the invention, a toner for developing electrostatic images is provided in which the difference in gloss between an image fixed under low temperature and low pressure conditions and an image fixed under high temperature and high pressure conditions is small, compared to the case where the loss tangent tanδ of resin particles at 150°C exceeds 2.5. <4> According to the invention, a toner for developing electrostatic images is provided in which the difference in gloss between an image fixed under low temperature and low pressure conditions and an image fixed under high temperature and high pressure conditions is smaller compared to the case where the number-average particle size of the resin particles exceeds 300 nm. <5> According to the invention, a toner for developing electrostatic images is provided in which the difference in gloss between an image fixed under low temperature and low pressure conditions and an image fixed under high temperature and high pressure conditions is smaller compared to the case in which the resin particle content is less than 2% by mass. <6> According to the invention, a toner for developing electrostatic images is provided in which the difference in gloss between an image fixed under low temperature and low pressure conditions and an image fixed under high temperature and high pressure conditions is smaller compared to the case where the resin particles are non-crosslinked resin particles. <7> According to the invention, a toner for developing electrostatic images is provided in which the difference in gloss between an image fixed under low temperature and low pressure conditions and an image fixed under high temperature and high pressure conditions is smaller compared to the case where the resin particles are polyester resin particles.

[0021] <8> According to the invention, a toner for developing electrostatic images is provided in which the difference in gloss between an image fixed under low temperature and low pressure conditions and an image fixed under high temperature and high pressure conditions is smaller compared to the case where the difference (SP value (S) - SP value (R)) is less than -0.32. <9> According to the invention, the storage modulus G' of the component obtained by removing resin particles from toner particles is 1 × 10 5 Compared to cases where the temperature at which Pa is reached exceeds 90°C, a toner for developing electrostatic images with better fixing properties is provided. <10> According to the invention, the storage modulus G' of the component obtained by removing resin particles from toner particles is 1 × 10 5 A toner for developing electrostatic images is provided that exhibits a smaller difference in gloss between images fixed under low-temperature, low-pressure conditions and images fixed under high-temperature, high-pressure conditions, compared to cases where the loss tangent tanδ at temperatures below Pa exceeds 1.6.

[0022] <11> According to the invention, G'(p90-150) is 1 × 10 4 Less than Pa or 1 x 10 6 A toner for developing electrostatic images is provided that exhibits a smaller difference in gloss between images fixed under low temperature and low pressure conditions and images fixed under high temperature and high pressure conditions, compared to cases where the Pa value exceeds Pa, or where logG'(t90-150)-logG'(r90-150) is less than 1.0 or greater than 4.0. <12> According to the invention, the storage modulus G' of the toner for electrostatic image development is 1 × 10 5 Compared to cases where the temperature at which Pa is reached exceeds 90°C, a toner for developing electrostatic images with better fixing properties is provided. <13> According to the invention, a toner for developing electrostatic images is provided in which the difference in gloss between an image fixed under low temperature and low pressure conditions and an image fixed under high temperature and high pressure conditions is smaller compared to the case where the crystalline resin content exceeds 50% by mass. <14> According to the invention, a toner for developing electrostatic images with better fixing properties is provided compared to the case where the binder resin is made of styrene acrylic resin. <15> According to the invention, a toner for developing electrostatic images is provided in which the difference in gloss between an image fixed under low temperature and low pressure conditions and an image fixed under high temperature and high pressure conditions is smaller compared to cases in which the binder resin does not contain an amorphous polyester resin having aliphatic dicarboxylic acid units or a crystalline polyester resin having aliphatic dicarboxylic acid units. <16> According to the invention, a toner for developing electrostatic images is provided that exhibits a smaller difference in gloss between an image fixed under low temperature and low pressure conditions and an image fixed under high temperature and high pressure conditions, compared to cases where a difunctional alkyl acrylate is not used as a constituent unit, or where a difunctional alkyl acrylate is used as a constituent unit and the number of carbon atoms in the alkylene chain of the difunctional alkyl acrylate is 5 or less.

[0023] <17> , <18> , <19> , <20> , or <21> According to the present invention, when an electrostatic image developing toner is applied in which any of D1(90), D50(90), D1(150), and D50(150) is less than 0.5 or greater than 2.5, the value of D50(150)-D1(150) is 1.5 or greater, or the value of D50(90)-D1(90) is 1.0 or greater, when an electrostatic image developing toner is applied in which the toner particles do not contain resin particles, or when an electrostatic image developing toner is applied in which the number average molecular weight of the tetrahydrofuran soluble components in the toner particles is less than 5000 or greater than 15000, the difference in gloss between the image fixed under low temperature and low pressure conditions and the image fixed under high temperature and high pressure conditions is small, while obtaining good fixing performance. [Brief explanation of the drawing]

[0024] [Figure 1] This is a schematic diagram showing an example of an image forming apparatus according to this embodiment. [Figure 2] This is a schematic diagram showing an example of a process cartridge that can be attached to and detached from the image forming apparatus according to this embodiment. [Modes for carrying out the invention]

[0025] The following describes an example embodiment of the present invention. These descriptions and examples are illustrative and do not limit the scope of the invention. In numerical ranges described stepwise within this specification, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range described stepwise. Furthermore, in numerical ranges described within this specification, the upper or lower limit of that range may be replaced with the values ​​shown in the examples. In this specification, (meth)acrylic means both acrylic and methacrylic.

[0026] In this specification, the term "process" refers not only to an independent process but also to a process that is clearly distinguished from other processes. Even if it is not possible to distinguish between them, if the intended purpose of the process is achieved, it is included in this term. Each component may contain multiple types of the relevant substance. When referring to the amount of each component in a composition, if there are multiple substances corresponding to each component in the composition, unless otherwise specified, it refers to the total amount of those multiple substances present in the composition.

[0027] [Toner for developing electrostatic images] The electrostatic image developing toner according to this embodiment (hereinafter also referred to as "toner") is an electrostatic image developing toner containing toner particles containing a binder resin, wherein in the dynamic viscoelasticity measurement of the electrostatic image developing toner, the loss tangent tanδ at a temperature of 90°C and a strain of 1% is D1(90), the loss tangent tanδ at a temperature of 90°C and a strain of 50% is D50(90), the loss tangent tanδ at a temperature of 150°C and a strain of 1% is D1(150), and the loss tangent tanδ at a temperature of 150°C and a strain of 50% When the loss tangent tanδ is D50(150), D1(90), D50(90), D1(150), and D50(150) are each between 0.5 and 2.5, the value of D50(150)-D1(150) is less than 1.5, the value of D50(90)-D1(90) is less than 1.0, the toner particles further contain resin particles, and the number-average molecular weight of the tetrahydrofuran-soluble components in the toner particles is between 5000 and 15000. Hereinafter, tetrahydrofuran-soluble components will also be referred to as "THF-soluble components." Furthermore, toners in which D1(90), D50(90), D1(150), and D50(150) are each between 0.5 and 2.5, D50(150)-D1(150) is less than 1.5, D50(90)-D1(90) is less than 1.0, the toner particles further contain resin particles, and the number-average molecular weight of the THF-soluble components in the toner particles is between 5000 and 15000 will also be referred to as "specific toners."

[0028] The toner according to this embodiment, with the above configuration, achieves good fixation while reducing the difference in gloss between the image fixed under low temperature and low pressure conditions and the image fixed under high temperature and high pressure conditions. The reason for this is presumed to be as follows. Hereinafter, the difference in gloss between the image fixed under low temperature and low pressure conditions and the image fixed under high temperature and high pressure conditions will also be referred to as the "gloss condition difference".

[0029] As mentioned above, in order to obtain good fixation, it is conceivable to use a toner for electrostatic image development that contains toner particles that melt easily when heated. On the other hand, when image formation is performed using a toner containing toner particles that melt easily when heated, the difference in gloss conditions may become large. This is presumed to be because the amount of deformation of the toner particles at high temperature and high distortion is larger than the amount of deformation of the toner particles at low temperature and low distortion.

[0030] Here, a strain of 1% in dynamic viscoelasticity measurement means applying a displacement of 1% relative to the height (i.e., gap) of the sample. In other words, a strain of 1% applies a small displacement and corresponds to low fuser pressure in the toner fixing process. On the other hand, a strain of 50% corresponds to high fuser pressure in the toner fixing process. Furthermore, a temperature of 90°C and a strain of 1% corresponds to fixing conditions at low temperature and low pressure, and a temperature of 150°C and a strain of 50% corresponds to fixing conditions at high temperature and high pressure. Each loss tangent tanδ corresponds to the amount of toner deformation under each fixing condition. It is presumed that by controlling the difference between the loss tangent tanδ at a strain of 1% and the loss tangent tanδ at a strain of 50% to be within a certain range, it is possible to suppress the amount of toner deformation within a certain range and suppress the difference in glossiness even when the fuser pressure is changed.

[0031] Furthermore, the toner of this embodiment is the specific toner described above. That is, D1(90), D50(90), D1(150), and D50(150) are all between 0.5 and 2.5, the value of D50(150)-D1(150) is less than 1.5, the value of D50(90)-D1(90) is less than 1.0, the toner particles further contain resin particles, and the number-average molecular weight of the THF-soluble components in the toner particles is between 5000 and 15000. In the specific toner described above, the change in the loss tangent with respect to the change in strain is small at both 90°C and 150°C. Therefore, it is presumed that because the toner has similar viscoelasticity at high temperature and high strain, and low temperature and low strain, even when fixing an image under high temperature and high pressure conditions, a fixed image with a small difference in glossiness compared to an image fixed under low temperature and low pressure conditions can be obtained. Furthermore, in this embodiment, since D1(90), D50(90), D1(150), and D50(150) are all 0.5 or greater, they melt more easily when heated during fixing compared to cases where any of them are less than 0.5, resulting in better fixing properties.

[0032] Furthermore, it is presumed that the inclusion of resin particles in the toner particles suppresses the deformation of the toner-fixed image in response to the fixing pressure, resulting in a fixed image with less difference in glossiness. In addition, when the number-average molecular weight of the THF-soluble components in the toner particles is between 5,000 and 15,000, the change in the loss tangent with respect to changes in strain is small, and high fixability can be obtained even with a highly viscoelastic toner in which deformation is suppressed. Specifically, when the number-average molecular weight of the THF-soluble components is within the above range, compared to when it is too small, the large amount of deformation of the toner particles and the resulting large difference in glossiness under high temperature and high pressure fixing conditions, which are caused by the presence of many low molecular weight components in the toner particles, are suppressed. Also, when the number-average molecular weight of the THF-soluble components is within the above range, compared to when it is too large, the amount of deformation of the toner particles is suppressed, while the difficulty in obtaining low-temperature fixability, which is caused by the presence of many high molecular weight components in the toner particles, is suppressed. It is even more preferable that the number-average molecular weight of the THF-soluble components be between 7,000 and 10,000.

[0033] As described above, in this embodiment, it is presumed that good fixation is achieved while reducing the difference in gloss between the image fixed under low temperature and low pressure conditions and the image fixed under high temperature and high pressure conditions.

[0034] The loss tangent of the above toner can be calculated as follows. Specifically, the toner to be measured is molded into a tablet shape using a press molding machine at room temperature (25°C) to prepare the sample for measurement. Then, using this sample for measurement, rheome Dynamic viscoelasticity measurements were performed under the following conditions using the provided data. From the obtained storage modulus and loss modulus curves, the loss tangent tanδ at temperatures of 90°C or 150°C and strain amounts of 1% or 50% was determined, yielding D1(90), D50(90), D1(150), and D50(150). -Measurement conditions- Measuring device: Rheometer ARES-G2 (manufactured by T.A. Instruments Co., Ltd.) Measuring jig: 8mm parallel plate Gap: Adjusted to 3mm Frequency: 1Hz

[0035] The number-average molecular weight of the THF-soluble component in the above-mentioned toner particles is determined by preparing the THF-soluble component of the toner particles using two "HLC-8120GPC, SC-8020 (6.0mm ID × 15cm manufactured by Tosoh Corporation)" vials and tetrahydrofuran (THF) as the eluent. Specifically, 0.5 mg of the toner particles to be measured are dissolved in 1 g of THF, ultrasonically dispersed, and then adjusted to a concentration of 0.5% by mass. Measurements were performed using an RI detector under the following conditions: sample concentration 0.5% by mass, flow rate 0.6 ml / min, sample injection volume 10 μl, and measurement temperature 40°C. Furthermore, the calibration curve will be prepared from 10 samples of "Polystyrene standard samples TSK standard" manufactured by Tosoh Corporation: "A-500", "F-1", "F-10", "F-80", "F-380", "A-2500", "F-4", "F-40", "F-128", and "F-700".

[0036] When obtaining toner particles from externally added toner, for example, the toner is dispersed in an aqueous solution of 0.2% by mass of polyoxyethylene (10) octylphenyl ether to a concentration of 10% by mass. The external additive is then released by applying ultrasonic vibration (frequency 20kHz, output 30W) for 60 minutes while maintaining a temperature of 30°C or lower. The toner particles are then filtered and washed from the resulting dispersion to obtain toner particles from which the external additive has been removed.

[0037] Furthermore, there are no particular limitations on how to obtain specific toner cartridges. One method for obtaining a specific toner is, for example, to measure the storage modulus G' in the range of 90°C to 150°C in dynamic viscoelasticity measurements at a temperature increase of 2°C / min, where G' is 1 × 10⁻⁶. 4 Pa or more 1×10 6 One method involves evenly distributing resin particles with a Pa level of less than or equal to Pa in both the region near the surface of the toner particle and the region near the center of the toner particle. Below, the storage modulus G' in the range of 90°C to 150°C is 1 × 10⁻⁶. 4 Pa or more 1×10 6 Resin particles with a Pa level of less than or equal to Pa are also called "specific resin particles." The reason why evenly dispersing specific resin particles in both the area near the surface and the area near the center of the toner particles makes it easier to obtain a specific toner is not entirely clear, but it is speculated to be as follows.

[0038] As described above, the storage modulus G' of the specific resin particles remains at 1 × 10⁻⁶ even when the temperature is raised to 150°C. 4 These are particles with an elastic modulus of Pa or higher. In other words, these specific resin particles are particles with a high elastic modulus at high temperatures. Therefore, it is presumed that the inclusion of these specific resin particles in the toner particles makes it less likely for the overall loss tangent of the toner to be high at high temperatures and high strain, and reduces the difference between this and the overall loss tangent of the toner at low temperatures and low strain. In particular, by evenly dispersing specific resin particles in both the region near the surface of the toner particles and the region near the center of the toner particles, the toner loss tangent is reduced at both low temperatures with low strain and high temperatures with high strain, and the difference between them also becomes smaller, making it easier to obtain the specific toner.

[0039] In order to encapsulate specific resin particles within toner particles, it is preferable that the specific resin particles have a high affinity for the binder resin. Specific methods for increasing this affinity include controlling the SP value and using a surfactant as a dispersant for the specific resin particles. However, when using specific resin particles with high affinity for the binder resin, unlike inorganic fillers, carbon black, and metal particles, these particles are composed of organic polymers, making them more compatible with the binder resin and potentially reducing their dispersibility. On the other hand, if specific resin particles with low affinity to the binder resin are used, they may not be easily encapsulated within the toner particles and may be discharged onto the surface of the toner particles or outside of the toner particles.

[0040] By using specific resin particles with an intermediate affinity between those with high affinity and those with low affinity to the binder resin, it becomes possible to encapsulate these specific resin particles within the toner particles to some extent. However, regardless of the toner manufacturing method, such as emulsification and agglomeration or kneading and grinding, when specific resin particles come into contact with each other, they tend to remain in contact and become unevenly distributed due to their high affinity as they are made of the same material. This makes it difficult to evenly distribute the specific resin particles within the toner particles. One reason why specific resin particles remain in contact with each other is thought to be that the polymer chains of the polymer components constituting the specific resin particles become entangled upon contact. Therefore, by using cross-linked resin particles as the specific resin particles, entanglement of polymer chains is suppressed, making it less likely for them to remain in contact and enabling them to be evenly distributed within the toner particles.

[0041] The storage modulus G' of the resin particles, as well as the loss tangent tanδ and glass transition temperature Tg (described later), are determined as follows. Specifically, by applying pressure to the resin particles to be measured, a disc-shaped sample with a thickness of 2 mm and a diameter of 8 mm is prepared and used as the measurement sample. When measuring resin particles contained in toner particles, the resin particles are extracted from the toner particles before preparing the measurement sample. Methods for extracting resin particles from toner particles include, for example, immersing the toner particles in a solvent that dissolves the binder resin but not the resin particles, and then dissolving the binder resin in the solvent to extract the resin particles. The obtained disc-shaped sample for measurement is then sandwiched between 8 mm diameter parallel plates, and the measurement temperature is increased from 10°C to 150°C at a rate of 2°C / min with a strain of 0.1 to 100%, and dynamic viscoelasticity measurements are performed under the following conditions. From the storage modulus and loss modulus curves obtained from the measurement, the storage modulus G' and loss tangent tanδ are determined. The peak temperature of the loss tangent tanδ is defined as the glass transition temperature Tg. -Measurement conditions- Measuring device: Rheometer ARES-G2 (manufactured by T.A. Instruments Co., Ltd.) Gap: Adjusted to 3mm Frequency: 1Hz

[0042] The following describes the details of the toner according to this embodiment.

[0043] The toner according to this embodiment comprises toner particles and, if necessary, an external additive.

[0044] (Toner particles) The toner particles contain at least a binder resin and may contain other components as needed. Furthermore, as mentioned above, from the viewpoint of obtaining a specific toner, it is preferable that the toner particles further contain specific resin particles. The following describes toner particles containing binder resin and specific resin particles as an example of toner particles contained in a specific toner. Toner particles are composed of, for example, a binder resin, specific resin particles, and, if necessary, a colorant, a release agent, and other additives.

[0045] -Binding resin- Examples of binder resins include vinyl resins consisting of monomers such as styrenes (e.g., styrene, parachlorostyrene, α-methylstyrene, etc.), (meth)acrylic acid esters (e.g., methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, etc.), ethylenically unsaturated nitriles (e.g., acrylonitrile, methacrylonitrile, etc.), vinyl ethers (e.g., vinyl methyl ether, vinyl isobutyl ether, etc.), vinyl ketones (vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone, etc.), and olefins (e.g., ethylene, propylene, butadiene, etc.), or copolymers of two or more of these monomers. Examples of binder resins include non-vinyl resins such as epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, and modified rosin; mixtures of these with the aforementioned vinyl resins; and graft polymers obtained by polymerizing vinyl monomers in the presence of these. These binding resins may be used individually or in combination of two or more types.

[0046] The binder resin preferably contains polyester resin. By including polyester resin as the binder resin, when styrene (meth)acrylic resin particles are used as the specific resin particles, the difference between the solubility parameter SP value (S) of the specific resin particles and the solubility parameter SP value (R) of the binder resin (SP value (S) - SP value (R)) tends to fall within a favorable range. This makes it easier for the specific resin particles to disperse in the toner particles, resulting in a reduction in the difference in gloss conditions. When the difference (SP value (S) - SP value (R)) is within the above range, the affinity between the binder resin and the specific resin particles is higher compared to when it is too small, which suppresses partial compatibility and a decrease in dispersibility. Also, when the difference (SP value (S) - SP value (R)) is within the above range, the affinity between the binder resin and the specific resin particles is lower compared to when it is too large, which suppresses the specific resin particles from being encapsulated within the toner particles and being discharged onto the surface of the toner particles or outside the toner particles.

[0047] The binder resin preferably contains both crystalline and amorphous resins. Here, a crystalline resin refers to a material that exhibits a clear endothermic peak in differential scanning calorimetry (DSC), rather than a stepwise change in endothermic heat. On the other hand, amorphous resins are those that, in thermal analysis measurements using differential scanning calorimetry (DSC), exhibit only a stepwise endothermic change rather than a clear endothermic peak, are solid at room temperature, and become thermoplastic at temperatures above their glass transition temperature. Specifically, for example, a crystalline resin means that the full width at half maximum (FWHM) of the endothermic peak measured at a heating rate of 10°C / min is within 10°C, while an amorphous resin means a resin whose FWHM exceeds 10°C, or a resin in which no clear endothermic peak is observed.

[0048] This section will explain crystalline resins. Examples of crystalline resins include known crystalline resins such as crystalline polyester resins and crystalline vinyl resins (e.g., polyalkylene resins, long-chain alkyl (meth)acrylate resins, etc.). Among these, crystalline polyester resin is preferred in terms of the mechanical strength and low-temperature fixability of the toner.

[0049] • Crystalline polyester resin Crystalline polyester resins include, for example, polycondensates of polycarboxylic acids and polyhydric alcohols. Commercially available crystalline polyester resins may be used, or synthesized resins may be used. Here, in order to easily form a crystalline structure, polycondensates using polymerizable monomers having linear aliphatic structures are preferred over polymerizable monomers having aromatic structures.

[0050] Examples of polycarboxylic acids include aliphatic dicarboxylic acids (e.g., oxalic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, etc.), aromatic dicarboxylic acids (e.g., phthalic acid, isophthalic acid, terephthalic acid, dibasic acids such as naphthalene-2,6-dicarboxylic acid, etc.), their anhydrides, or their lower alkyl esters (e.g., having 1 to 5 carbon atoms). Polycarboxylic acids may be used in combination with dicarboxylic acids, or with trivalent or higher carboxylic acids that have a crosslinked or branched structure. Examples of trivalent carboxylic acids include aromatic carboxylic acids (e.g., 1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,2,4-naphthalentricarboxylic acid, etc.), their anhydrides, or their lower alkyl esters (e.g., having 1 to 5 carbon atoms). In addition to these dicarboxylic acids, polycarboxylic acids with sulfonic acid groups and dicarboxylic acids with ethylenic double bonds may also be used in combination. Polycarboxylic acids may be used individually or in combination of two or more.

[0051] Examples of polyhydric alcohols include aliphatic diols (for example, linear aliphatic diols with 7 to 20 carbon atoms in the main chain). Examples of aliphatic diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, and 1,14-eicosandecanediol. Among these, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferred as aliphatic diols. Polyhydric alcohols may be used in combination with diols, including trihydric or higher alcohols that have a cross-linked or branched structure. Examples of trihydric or higher alcohols include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol. Polyhydric alcohols may be used individually or in combination of two or more types.

[0052] Here, the polyhydric alcohol is preferably composed of 80 mol% or more of aliphatic diols, and more preferably 90 mol% or more.

[0053] The melting temperature of the crystalline polyester resin is preferably 50°C to 100°C, more preferably 55°C to 90°C, and even more preferably 60°C to 85°C. The melting temperature is determined from the DSC curve obtained by differential scanning calorimetry (DSC) using the "melting peak temperature" described in JIS K7121-1987 "Method for determining the transition temperature of plastics".

[0054] The weight-average molecular weight (Mw) of crystalline polyester resin is between 6,000 and 35,000. The bottom is preferable.

[0055] Crystalline polyester resins can be obtained, for example, by well-known manufacturing methods, similar to amorphous polyesters.

[0056] When toner particles contain crystalline resin, the content of crystalline resin relative to the total binder resin is preferably 4% by mass or more and 50% by mass or less, more preferably 6% by mass or more and 30% by mass or less, and even more preferably 8% by mass or more and 20% by mass or less. Having a crystalline resin content within the above range makes it easier to obtain better adhesion compared to when the content is lower. Furthermore, having a crystalline resin content within the above range suppresses the excessive increase in gloss of the fixed image under high temperature and pressure conditions, which can occur due to an excess of relatively low-elasticity crystalline resin, compared to when the content is higher. This reduces the difference in gloss levels.

[0057] This section will explain amorphous resins. Examples of amorphous resins include known amorphous resins such as amorphous polyester resin, amorphous vinyl resin (e.g., styrene-acrylic resin), epoxy resin, polycarbonate resin, and polyurethane resin. Among these, amorphous polyester resin and amorphous vinyl resin (particularly styrene-acrylic resin) are preferred, and amorphous polyester resin is more preferred.

[0058] Amorphous polyester resin Examples of amorphous polyester resins include condensation polymers of polycarboxylic acids and polyhydric alcohols. The amorphous polyester resin may be a commercially available product or a synthesized one.

[0059] Examples of polycarboxylic acids include aliphatic dicarboxylic acids (e.g., oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, alkenylsuccinic acid, adipic acid, sebacic acid, etc.), alicyclic dicarboxylic acids (e.g., cyclohexanedicarboxylic acid, etc.), aromatic dicarboxylic acids (e.g., terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, etc.), their anhydrides, or their lower alkyl esters (e.g., with 1 to 5 carbon atoms). Among these, aromatic dicarboxylic acids are preferred as polycarboxylic acids. Polycarboxylic acids may be used in combination with dicarboxylic acids, or with trivalent or higher carboxylic acids that have a cross-linked or branched structure. Examples of trivalent or higher carboxylic acids include trimellitic acid, pyromellitic acid, their anhydrides, or their lower alkyl esters (e.g., having 1 to 5 carbon atoms). Polycarboxylic acids may be used individually or in combination of two or more.

[0060] Examples of polyhydric alcohols include aliphatic diols (e.g., ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, etc.), alicyclic diols (e.g., cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, etc.), and aromatic diols (e.g., ethylene oxide adducts of bisphenol A, propylene oxide adducts of bisphenol A, etc.). Among these, aromatic diols and alicyclic diols are preferred as polyhydric alcohols, and aromatic diols are more preferred. As for the polyhydric alcohol, a trihydric or higher polyhydric alcohol with a cross-linked or branched structure may be used in combination with the diol. Examples of trihydric or higher polyhydric alcohols include glycerin, trimethylolpropane, and pentaerythritol. Polyhydric alcohols may be used individually or in combination of two or more types.

[0061] The glass transition temperature (Tg) of amorphous polyester resin is preferably 50°C to 80°C, and more preferably 50°C to 65°C. The glass transition temperature is determined from the DSC curve obtained by differential scanning calorimetry (DSC), and more specifically, it is determined by the "extracorporeal glass transition onset temperature" described in the method for determining the glass transition temperature in JIS K 7121-1987 "Method for Measuring the Transition Temperature of Plastics".

[0062] The weight-average molecular weight (Mw) of the amorphous polyester resin is preferably 5,000 to 1,000,000, and more preferably 7,000 to 500,000. The number-average molecular weight (Mn) of the amorphous polyester resin is preferably between 2,000 and 100,000. The molecular weight distribution (Mw / Mn) of the amorphous polyester resin is preferably 1.5 to 100, and more preferably 2 to 60. The weight-average molecular weight and number-average molecular weight are measured by gel permeation chromatography (GPC). GPC molecular weight measurement is performed using a Tosoh GPC-HLC-8120GPC analyzer, a Tosoh TSKgel SuperHM-M (15cm) column, and THF solvent. The weight-average molecular weight and number-average molecular weight are calculated from these measurement results using a molecular weight calibration curve prepared with monodisperse polystyrene standard samples.

[0063] Amorphous polyester resins can be obtained by well-known manufacturing methods. Specifically, for example, they can be obtained by a method in which the polymerization temperature is set to 180°C or higher and 230°C or lower, and the reaction system is subjected to reduced pressure as needed, while removing water and alcohol generated during condensation. If the monomers of the raw materials do not dissolve or become miscible at the reaction temperature, a high-boiling point solvent may be added as a solubilizer to dissolve them. In this case, the polycondensation reaction should be carried out while distilling off the solubilizer. If there are monomers with poor miscibility, it is advisable to condense the poorly miscible monomers with the acid or alcohol to be polycondensed with them beforehand, and then polycondense them together with the main component.

[0064] The binder resin preferably contains a polyester resin having aliphatic dicarboxylic acid units (i.e., structural units derived from aliphatic dicarboxylic acids). When the polyester resin used as the binder has aliphatic dicarboxylic acid units, the flexibility of the binder resin is increased compared to when it has only aromatic dicarboxylic acid units, which allows for a more uniform dispersion of specific resin particles and reduces the range of change in the loss tangent tanδ.

[0065] Furthermore, it is preferable that the binder resin includes an amorphous polyester resin having aliphatic dicarboxylic acid units and a crystalline polyester resin having aliphatic dicarboxylic acid units. When the binder resin includes both amorphous and crystalline polyester resins, the presence of aliphatic dicarboxylic acid units in both allows for more uniform dispersion of specific resin particles.

[0066] For example, an aliphatic dicarboxylic acid is one with the general formula "HOOC-(CH2) n A saturated aliphatic dicarboxylic acid represented by "-COOH" can be preferably used. In the above general formula, n is preferably 4 to 20, and more preferably 4 to 12.

[0067] The binder resin content is preferably 40% to 95% by mass, more preferably 50% to 90% by mass, and even more preferably 60% to 85% by mass, relative to the total toner particles.

[0068] The ratio of the crystalline resin content to the specific resin particle content is preferably 0.2 to 10, and more preferably 1 to 5, when the specific resin particle content is set to 1. When the ratio of crystalline resin content to specific resin particle content is within the above range, compared to when it is less than 0.2, the amount of low-viscosity components in the toner at temperatures between 90°C and 150°C is reduced, and the contribution of specific resin particles, which are high-elasticity components, becomes larger. This suppresses the decrease in toner melting properties and improves fixability. Furthermore, by keeping the ratio of crystalline resin content to specific resin particle content within the above range, compared to cases where the ratio exceeds 10, the excess reduction component is suppressed, which leads to increased toner deformation due to heat and pressure from the fuser, and the difference in glossiness depending on the fixing conditions becomes smaller. Furthermore, the ratio of amorphous resin content to specific resin particle content is preferably 1.3 to 45, and more preferably 3 to 15, when the specific resin particle content is set to 1.

[0069] -Specific resin particles- The specific resin particles exhibited a storage modulus G' of 1 × 10 in the range of 90°C to 150°C in dynamic viscoelasticity measurements during a 2°C / min temperature increase. 4 Pa or more 1×10 6 Any resin particle with a Pa value of less than or equal to Pa will suffice; there are no particular limitations. The storage modulus G' of a specific resin particle in the range of 90°C to 150°C is 1 × 10⁻⁶ 5 Pa or more 8×10 5 It is preferable that the Pa is less than or equal to 1 × 10 5 Pa or more 6×10 5 It is more preferable that the value be Pa or less. By using resin particles whose storage modulus G' in the range of 90°C to 150°C is within the above range, the excessive increase in glossiness of the fixed image fixed under high temperature and high pressure conditions is suppressed compared to when using resin particles with a lower storage modulus G'. This reduces the difference in glossiness conditions. Furthermore, by using resin particles whose storage modulus G' in the range of 90°C to 150°C is within the above range, the decrease in fixability caused by excessively high elasticity of the toner particles is suppressed compared to when using resin particles with a higher storage modulus G', making it easier to obtain good fixability.

[0070] The specified resin particles have a loss tangent tanδ of 0.01 to 2.5 in the range of 30°C to 150°C in dynamic viscoelasticity measurements at a heating rate of 2°C / min. Preferred. The specific resin particles are more preferably such that the loss tangent tanδ in the range of 65°C to 150°C is 0.01 to 1.0, and even more preferably 0.01 to 0.5. When the loss tangent tanδ of specific resin particles in the range of 30°C to 150°C is within the above range, the toner particles deform more easily during fixing compared to when the temperature is lower than the above range, making it easier to obtain good fixing performance. Furthermore, when the loss tangent tanδ of specific resin particles in the range of 65°C to 150°C, which is a temperature in which toner particles are more easily deformed, is within the above range, the excessive increase in glossiness of the fixed image fixed under high temperature and high pressure conditions is suppressed compared to when the temperature is higher than the above range. As a result, the difference in glossiness conditions is reduced.

[0071] The specific resin particles are preferably crosslinked resin particles. Here, "crosslinked resin particles" refers to resin particles that have a crosslinking structure between specific atoms in the polymer structure contained within the resin particles.

[0072] By using cross-linked resin particles, it becomes easier to obtain specific resin particles whose storage modulus G' in the range of 90°C to 150°C falls within the aforementioned range, thus making it easier to obtain specific toner.

[0073] Examples of crosslinked resin particles include crosslinked resin particles crosslinked by ionic bonds (ionic crosslinked resin particles) and crosslinked resin particles crosslinked by covalent bonds (covalently crosslinked resin particles). Among these, crosslinked resin particles crosslinked by covalent bonds are preferred.

[0074] Examples of resins used in crosslinked resin particles include polyolefin resins (polyethylene, polypropylene, etc.), styrene resins (polystyrene, α-polymethylstyrene, etc.), (meth)acrylic resins (polymethyl methacrylate, polyacrylonitrile, etc.), epoxy resins, polyurethane resins, polyurea resins, polyamide resins, polycarbonate resins, polyether resins, polyester resins, and copolymers thereof. These resins may be used individually or in mixtures of two or more types as needed.

[0075] Among the resins mentioned above, styrene-(meth)acrylic copolymer resins are preferred as the resin used for the crosslinked resin particles. In other words, styrene-(meth)acrylic copolymer resin particles are preferred as the crosslinked resin particles.

[0076] Because the crosslinked resin particles are styrene-(meth)acrylic copolymer resin particles, the storage modulus G' in the range of 90°C to 150°C is more likely to be within the specified range, making it easier to obtain a specific toner.

[0077] Examples of styrene-(meth)acrylic copolymer resins include resins obtained by polymerizing the following styrene monomers and (meth)acrylic acid monomers by radical polymerization.

[0078] Examples of styrene monomers include styrene, α-methylstyrene, vinylnaphthalene, alkyl-substituted styrenes having alkyl chains such as 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, and 4-ethylstyrene, halogen-substituted styrenes such as 2-chlorostyrene, 3-chlorostyrene, and 4-chlorostyrene, and fluorine-substituted styrenes such as 4-fluorostyrene and 2,5-difluorostyrene. Among these, styrene and α-methylstyrene are preferred.

[0079] Examples of (meth)acrylic acid monomers include (meth)acrylic acid, n-methyl (meth)acrylate, n-ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, n-lauryl (meth)acrylate, n-tetradecyl (meth)acrylate, n-hexadecyl (meth)acrylate, n-octadecyl (meth)acrylate, isopropyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, isopentyl (meth)acrylate, amyl (meth)acrylate, (meth)acrylate Examples include neopentyl acrylate, isohexyl methacrylate, isoheptyl methacrylate, isooctyl methacrylate, 2-ethylhexyl methacrylate, phenyl methacrylate, biphenyl methacrylate, diphenylethyl methacrylate, t-butylphenyl methacrylate, terphenyl methacrylate, cyclohexyl methacrylate, t-butylcyclohexyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, methoxyethyl methacrylate, 2-hydroxyethyl methacrylate, 2-carboxyethyl methacrylate, acrylonitrile, and methacrylamide. Among these, n-butyl methacrylate and 2-carboxyethyl methacrylate are preferred.

[0080] In crosslinked resin particles, crosslinking agents for crosslinking the resin include, for example, aromatic polyvinyl compounds such as divinylbenzene and divinylnaphthalene; polyvinyl esters of aromatic polycarboxylic acids such as divinyl phthalate, divinyl isophthalate, divinyl terephthalate, divinyl homophthalate, divinyl trimesicate, trivinyl trimesicate, divinyl naphthalenedicarboxylate, and divinyl biphenylcarboxylate; divinyl esters of nitrogen-containing aromatic compounds such as divinyl pyridinedicarboxylate; vinyl esters of unsaturated heterocyclic compound carboxylic acids such as vinyl pyromutinate, vinyl furanate, vinyl pyrrole-2-carboxylate, and vinyl thiophenecarboxylate; butanediol diacrylate, butanediol dimethacrylate, hexanediol diacrylate, hexanediol dimethacrylate, octanediol diacrylate, octanediol dimethacrylate, nonanediol diacrylate, nonanediol dimethacrylate, decanediol diacrylate, decanediol diacrylate (Meth)acrylic acid esters of linear polyhydric alcohols such as diol dimethacrylate, dodecanediol diacrylate, and dodecanediol dimethacrylate; (Meth)acrylic acid esters of branched and substituted polyhydric alcohols such as neopentyl glycol dimethacrylate and 2-hydroxy,1,3-diacryloxypropane; polyethylene glycol di(meth)acrylate, polypropylene polyethylene glycol di(meth)acrylates, divinyl succinate, divinyl fumarate, and maleic acid Examples include polyvinyl esters of polycarboxylic acids such as vinyl, divinyl maleate, divinyl diglycolate, vinyl itaconate, divinyl itaconate, divinyl acetonedicarboxylate, divinyl glutarate, divinyl 3,3'-thiodipropionate, divinyl trans-aconitate, trivinyl trans-aconitate, divinyl adipicate, divinyl pimephosphate, divinyl suberate, divinyl azelaate, divinyl sebacate, divinyl dodecanediate, and divinyl brassylate. The crosslinking agent may be used alone or in combination of two or more types.

[0081] Among these, it is preferable to use a difunctional alkyl acrylate having an alkylene chain with 6 or more carbon atoms as a crosslinking agent for crosslinking the resin. In other words, it is preferable that the crosslinked resin particles have a difunctional alkyl acrylate as a constituent unit, and that the alkylene chain in the difunctional alkyl acrylate has 6 or more carbon atoms. Using crosslinked resin particles that have a bifunctional alkyl acrylate as a constituent unit and whose alkylene chain has 6 or more carbon atoms makes it easier to obtain a specific toner. In specific toners, it is important to suppress the deformation of the toner particles within a certain range even under high-pressure fixing conditions in order to suppress the difference in gloss. If the difference in elasticity between the specific resin particles, which are crosslinked resin particles, and the binder resin is too large, it may be difficult to obtain the effect of suppressing the change in loss tangent tanδ by the specific resin particles. For this reason, it is preferable to control the elasticity of the specific resin particles so that it does not become too high. When the crosslinking density of the specific resin particles is high (i.e., the distance between crosslinking points is short), the elasticity becomes too high. However, when a bifunctional acrylate with a long-chain alkylene chain is used as the crosslinking agent, the crosslinking density becomes low (i.e., the distance between crosslinking points is long), and it is possible to suppress the elasticity of the specific resin particles from becoming too high. As a result, the difference in gloss can be further suppressed.

[0082] From the viewpoint of adjusting the crosslinking density to an appropriate range, the number of carbon atoms in the alkylene chain of the difunctional alkyl acrylate is preferably 6 or more, more preferably 6 to 12, and even more preferably 8 to 12. More specific examples of difunctional alkyl acrylates include 1,6-hexanediol acrylate, 1,6-hexanediol methacrylate, 1,8-octanediol diacrylate, 1,8-octanediol dimethacrylate, 1,9-nonanediol diacrylate, 1,9-nonanediol dimethacrylate, 1,10-decanediol diacrylate, 1,10-decanediol dimethacrylate, 1,12-dodecanediol diacrylate, and 1,12-dodecanediol dimethacrylate, among which 1,10-decanediol diacrylate and 1,10-decanediol dimethacrylate are preferred.

[0083] Furthermore, if the specific resin particles are polymers of a composition for forming specific resin particles containing a styrene monomer, a (meth)acrylic acid monomer, and a crosslinking agent, the viscoelasticity of the specific resin particles may be controlled by adjusting the amount of crosslinking agent contained in the composition. For example, increasing the amount of crosslinking agent contained in the composition makes it easier to obtain resin particles with a high storage modulus G'. The crosslinking agent content in the composition for forming specific resin particles is preferably 0.3 parts by mass or more and 5.0 parts by mass or less, more preferably 0.5 parts by mass or more and 2.5 parts by mass or less, and even more preferably 1.0 part by mass or more and 2.0 parts by mass or less, per 100 parts by mass of the total of the styrene monomer, (meth)acrylic acid monomer, and crosslinking agent.

[0084] The glass transition temperature Tg, determined from dynamic viscoelasticity measurements of specific resin particles, is preferably between 10°C and 45°C. When the glass transition temperature Tg of the specific resin particles is between 10°C and 45°C, the toner achieves better fixation while reducing the difference in gloss between the image fixed under low-temperature, low-pressure conditions and the image fixed under high-temperature, high-pressure conditions. Furthermore, the glass transition temperature Tg of the specific resin particles is preferably 15°C to 40°C, and more preferably 20°C to 35°C. When the glass transition temperature (Tg) of the specific resin particles is within the above range, compared to when the Tg is too low, the large difference in Tg between the specific resin particles and the binder resin, which tends to cause uneven distribution of resin particles within the toner particles, is suppressed. This makes it easier to maintain a nearly uniform dispersion state of the specific resin particles, resulting in a greater effect in suppressing deformation under pressure during fixing and reducing the difference in gloss. Furthermore, when the glass transition temperature (Tg) of the specific resin particles is within the above range, compared to when the Tg is too high, the deterioration of low-temperature fixing performance caused by the deterioration of the binder resin's melting properties is suppressed.

[0085] The number-average particle size of the specific resin particles is preferably 60 nm to 300 nm, more preferably 100 nm to 200 nm, and even more preferably 130 nm to 170 nm. When the number-average particle size of the specific resin particles is within the above range, the decrease in fixation due to the toner particles being more susceptible to the high elasticity of the specific resin particles is suppressed compared to when it is smaller than the above range, resulting in good fixation. Furthermore, when the number-average particle size of the specific resin particles is within the above range, the specific resin particles tend to disperse more uniformly within the toner particles compared to when it is larger than the above range, making it easier to obtain a toner with similar viscoelasticity at high temperature and high strain, and low temperature and low strain. As a result, the difference in gloss conditions is reduced.

[0086] The number-average particle size of a specific resin particle is a value measured using a transmission electron microscope (TEM). As a transmission electron microscope, for example, the JEM-1010 manufactured by JEOL Datum Ltd. can be used. The following describes in detail the method for measuring the number-average particle size of specific resin particles. The toner particles are cut into pieces approximately 0.3 μm thick using a microtome. A 4500x magnification image of the cross-section of the toner particles is taken using a transmission electron microscope. For 1000 resin particles dispersed within the toner particles, the equivalent diameter of each circle is calculated from the cross-sectional area of ​​each particle, and the arithmetic mean of these values ​​is used as the number-average particle size. Furthermore, the number-average particle size of the specific resin particles may be a value measured using a laser diffraction particle size distribution analyzer (for example, LA-700 manufactured by Horiba, Ltd.) with a dispersion of the specific resin particles.

[0087] It is preferable that the specific resin particles are evenly distributed in both the region near the surface of the toner particle (hereinafter also referred to as the "surface region") and the region near the center of the toner particle (hereinafter also referred to as the "center region"). By including the specific resin particles in both the surface region and the center region, the difference in gloss level conditions is reduced compared to the case where the specific resin particles are included in only one of the two regions. For example, if specific resin particles are contained only in the surface region, under low temperature and low pressure conditions, the deformation of the toner particles will be small due to the viscoelasticity of the surface region, whereas under high temperature and high pressure conditions, the deformation of the toner particles will be large due to the viscoelasticity of the central region. Therefore, the difference in gloss conditions may be large. Also, if specific resin particles are contained only in the central region, under low temperature and low pressure conditions, the deformation of the toner particles will be small, and the dispersion of the specific resin particles in the fixed image will be poor (unevenly distributed), whereas under high temperature and high pressure conditions, the deformation of the toner particles will be large, and the dispersion of the specific resin particles in the fixed image will be good (nearly uniform). If the dispersion of the specific resin particles in the fixed image is poor, the areas where the specific resin particles are present will be less deformable and become convex, while the areas where the specific resin particles are absent will be more deformable and become concave, thus reducing the gloss. If the dispersion is good, the above conditions are suppressed, and the gloss increases. Therefore, the difference in gloss conditions may be large. In contrast, when specific resin particles are contained in both the surface and central regions, it is presumed that the difference in gloss conditions will be reduced, unlike when they are contained only in the surface region or only in the central region.

[0088] The content of specific resin particles is preferably 2% by mass or more and 30% by mass or less, more preferably 5% by mass or more and 25% by mass or less, and even more preferably 8% by mass or more and 20% by mass or less, relative to the total toner particles. By having a specific resin particle content within the above range, the toner tends to have similar viscoelasticity at high temperatures and low temperatures compared to when the content is lower than the above range, thus reducing the difference in gloss conditions. Furthermore, by having a specific resin particle content within the above range, the decrease in fixation due to excessively high elasticity of the toner particles is suppressed compared to when the content is higher than the above range, resulting in good fixation.

[0089] -Colorants- Examples of colorants include carbon black, chrome yellow, Hansa yellow, benzidine yellow, surene yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, balkan orange, Watch Young red, permanent red, brilliant carmine 3B, brilliant carmine 6B, DuPont oil red, pyrazolone red, risole red, rhodamine B lake, lake red C, pigment red, rose bengal, aniline blue, and ultramarine. Examples include various pigments such as phosphorus blue, chalcioyl blue, methylene blue chloride, phthalocyanine blue, pigment blue, phthalocyanine green, and malachite green oxalate, as well as various dyes such as acridine, xanthene, azo, benzoquinone, azine, anthraquinone, thioindico, dioxazine, thiazine, azomethine, indico, phthalocyanine, aniline black, polymethine, triphenylmethane, diphenylmethane, and thiazole. Colorants may be used individually or in combination of two or more types.

[0090] The coloring agent may be a surface-treated coloring agent as needed, and may be used in combination with a dispersant. Furthermore, multiple types of coloring agents may be used in combination.

[0091] The colorant content is preferably 1% to 30% by mass, and more preferably 3% to 15% by mass, relative to the total toner particles.

[0092] -Release agent- Examples of release agents include hydrocarbon waxes; natural waxes such as carnauba wax, rice wax, and candelilla wax; synthetic or mineral / petroleum-based waxes such as montan wax; and ester waxes such as fatty acid esters and montanic acid esters. However, the release agents are not limited to these.

[0093] The melting temperature of the release agent is preferably 50°C to 110°C, and more preferably 60°C to 100°C. The melting temperature is determined from the DSC curve obtained by differential scanning calorimetry (DSC) using the "melting peak temperature" described in JIS K 7121-1987 "Method for determining the transition temperature of plastics".

[0094] The release agent content is preferably 1% to 20% by mass, and more preferably 5% to 15% by mass, relative to the total toner particles.

[0095] -Other additives- Other additives include well-known additives such as magnetic materials, charge control agents, and inorganic powders. These additives are included in the toner particles as internal additives.

[0096] -Relationships of composition in toner particles- Difference (SP value (S) - SP value (R)) The difference between the solubility parameter SP value (S) of the specific resin particles and the solubility parameter SP value (R) of the binder resin (SP value (S) - SP value (R)) is preferably between -0.32 and -0.12.

[0097] When the difference (SP value (S) - SP value (R)) is within the above range, the affinity between the binder resin that makes up the majority of the toner particles and the specific resin particles is appropriately maintained compared to when it is smaller than the above range, and the specific resin particles are more easily dispersed in a nearly uniform state within the toner particles. As a result, the toner tends to have similar viscoelasticity at high temperature and high strain and low temperature and low strain, and the difference in gloss conditions is reduced. In other words, compared to when the difference (SP value (S) - SP value (R)) is smaller than the above range, it becomes less likely that the affinity between the binder resin and the specific resin particles will be too high, causing the specific resin particles to move easily within the toner particles, resulting in some of the specific resin particles agglomerating and reducing the effect of the specific resin particles. Furthermore, if the difference (SP value (S) - SP value (R)) is within the above range, then if it is greater than the above range... Compared to conventional methods, this method suppresses the increase in the overall melt viscosity of the toner caused by excessive mixing and compatibility of specific resin particles and binder resin during toner melting. As a result, the decrease in fixation performance caused by excessively high viscoelasticity is suppressed, and good fixation performance is achieved. If the binder resin is a mixed resin, the solubility parameter of the resin with the highest content ratio in the binder resin is defined as the SP value (R).

[0098] The difference (SP value (S) - SP value (R)) is more preferably between -0.32 and -0.12, and even more preferably between -0.29 and -0.18.

[0099] The solubility parameter SP value (S) of the specific resin particles is preferably 9.00 or more and 9.15 or less, more preferably 9.03 or more and 9.12 or less, and even more preferably 9.06 or more and 9.10 or less.

[0100] Here, the solubility parameter SP value (S) of the specific resin particles and the solubility parameter SP value (R) of the binder resin (unit: (cal / cm)) are given. 3 ) 1 / 2 The calculation is performed using the Okitsu method. The Okitsu method is described in detail in "Journal of the Adhesion Society of Japan, Vol. 29, No. 5 (1993)".

[0101] • Viscoelasticity of components excluding specific resin particles (excluded components) The storage modulus G' of the component obtained by removing specific resin particles from toner particles is 1 × 10 in the range of 30°C to 50°C. 8 The Pa value is greater than or equal to the storage modulus G' of 1 × 10⁻⁶. 5 It is preferable that the temperature at which Pa falls below 65°C is between 65°C and 90°C. Hereinafter, the components obtained by removing specific resin particles from the toner particles will also be called "excluded components," and their storage modulus G' is 1 × 10⁻⁶ 5The temperature at which the storage modulus G' reaches less than Pa is also called the "temperature at which the specific modulus is reached." Exclusion components whose storage modulus G' satisfies the above conditions have a high modulus at low temperatures and a low modulus between 65°C and 90°C. Therefore, when the storage modulus G' of an exclusion component satisfies the above conditions, the storage modulus G' becomes 1 × 10⁻⁶ 5 Compared to cases where the temperature below Pa exceeds 90°C, heating makes the toner particles melt more easily, resulting in better fixation.

[0102] The storage modulus G' for the excluded components at temperatures between 30°C and 50°C is 1 × 10⁻⁶ 8 Preferably Pa or higher, 1 × 10 8 Pa or more 1×10 9 It is more preferable that it be less than or equal to Pa, 2 × 10 8 Pa or more 6×10 8 It is even more preferable that it be Pa or less. Because the storage modulus G' of the excluded components at temperatures between 30°C and 50°C is within the above range, the storage stability of the toner is better compared to cases where the value is lower than the above range, and better fixation is more easily obtained compared to cases where the value is higher than the above range.

[0103] Furthermore, the temperature at which the specific elastic modulus is reached in the excluded components is preferably 65°C to 90°C, more preferably 68°C to 80°C, and even more preferably 70°C to 75°C. Because the temperature at which the specific elastic modulus is reached in the excluded components is within the above range, the storage stability of the toner is better compared to when it is lower than the above range, and better fixing performance is more easily obtained compared to when it is higher than the above range.

[0104] The loss tangent tanδ of the excluded component at the temperature at which the specific elastic modulus is reached is preferably 0.8 or more and 1.6 or less, more preferably 0.9 or more and 1.5 or less, and even more preferably 1.0 or more and 1.4 or less. Because the loss tangent tanδ at the temperature at which the specific elastic modulus of the excluded component is reached is within the above range, better adhesion is more easily obtained compared to when it is lower than the above range. Furthermore, because the loss tangent tanδ at the temperature at which the specific elastic modulus of the excluded component is reached is within the above range, the difference in gloss conditions is reduced compared to when it is higher than the above range.

[0105] The storage modulus G' and loss tangent tanδ of the excluded components are determined as follows. Specifically, the process involves first removing the resin particles from the toner particles to extract only the excluded components, and then molding these excluded components into tablets at 25°C using a press molding machine to prepare a sample for measurement. Methods for removing the resin particles from the toner particles to extract only the excluded components include, for example, immersing the toner particles in a solvent that dissolves the binder resin but not the resin particles, and then extracting the excluded components. The obtained sample for measurement is then sandwiched between 8 mm diameter parallel plates, and dynamic viscoelasticity measurements are performed under the following conditions, with a strain of 0.1 to 100% and the measurement temperature increased from 30°C to 150°C at a rate of 2°C / min. From the storage modulus and loss modulus curves obtained from the measurement, the storage modulus G' and loss tangent tanδ are determined. -Measurement conditions- Measuring device: Rheometer ARES-G2 (manufactured by T.A. Instruments Co., Ltd.) Measuring jig: 8mm parallel plate Gap: Adjusted to 3mm Frequency: 1Hz

[0106] • Relationship between specific resin particles, toner particles, and excluded components In the range of 90°C to 150°C, when the storage modulus of a specific resin particle is G'(p90-150), the storage modulus of a toner particle is G'(t90-150), and the storage modulus of the component obtained by removing the specific resin particle from the toner particle is G'(r90-150), then G'(p90-150) is 1 × 10⁻⁶. 4 Pa or more 1×10 6 It is preferable that the pressure is less than or equal to Pa, and that logG'(t90-150)-logG'(r90-150) is between 1.0 and 4.0. Furthermore, the value of logG'(t90-150)-logG'(r90-150) is more preferably between 1.0 and 3.5, even more preferably between 1.1 and 3.4, and particularly preferably between 1.2 and 3.3. The value of logG'(t90-150)-logG'(r90-150) represents the difference in viscoelasticity of toner particles with and without the addition of specific resin particles. By dispersing and encapsulating the specific resin particles in a nearly uniform manner within the toner particles, the influence of the viscoelasticity of the specific resin particles on the overall viscoelasticity of the toner particles is suppressed. By controlling the value of logG'(t90-150)-logG'(r90-150) within the above range, both good adhesion and reduced differences in gloss conditions are achieved compared to cases where the value is smaller or larger than the above range.

[0107] -Characteristics of toner particles, etc.- The toner particles may be single-layer toner particles, or they may be toner particles with a so-called core-shell structure, consisting of a core (core particle) and a coating layer (shell layer) that covers the core. Here, the toner particles of the core-shell structure preferably consist of a core portion comprising a binder resin, specific resin particles, and other additives such as colorants and release agents as needed, and a coating layer comprising a binder resin and specific resin particles.

[0108] When toner particles have a core-shell structure, it is preferable that specific resin particles are contained in both the core particles and the shell layer. By containing specific resin particles in both the core particles and the shell layer, the specific resin particles are contained in both the surface and central regions of the toner particles, further reducing the difference in gloss conditions.

[0109] The volume-average particle size (D50v) of the toner particles is preferably 2 μm or more and 10 μm or less, more preferably 4 μm or more and 8 μm or less, and even more preferably 4 μm or more and 6 μm or less.

[0110] The average particle size and particle size distribution indices of the toner particles are measured using the Coulter Multisizer II (manufactured by Beckman Coulter), and the electrolyte is measured using the ISOTON-II (manufactured by Beckman Coulter). For measurement, add 0.5 mg to 50 mg of the sample to be measured in 2 ml of a 5% aqueous solution of a surfactant (preferably sodium alkylbenzenesulfonate) as a dispersant. Add this to 100 ml to 150 ml of electrolyte. The electrolyte containing the suspended sample was dispersed in an ultrasonic disperser for 1 minute, and then subjected to Coulter MultiSyne. Using the ZAR II system, the particle size distribution of particles with a diameter of 2 μm to 60 μm will be measured using an aperture with a diameter of 100 μm. The number of particles to be sampled will be 50,000. Based on the measured particle size distribution, a cumulative distribution of volume and number is drawn for each divided particle size range (channel) from the smallest diameter side. The particle size at which the cumulative total reaches 16% is defined as the volume particle size D16v and the number particle size D16p, the particle size at which the cumulative total reaches 50% is defined as the volume average particle size D50v and the cumulative number average particle size D50p, and the particle size at which the cumulative total reaches 84% ​​is defined as the volume particle size D84v and the number particle size D84p. Using these, the volume particle size distribution index (GSDv) is (D84v / D16v) 1 / 2 The GSDp index is (D84p / D16p) 1 / 2 It is calculated as follows.

[0111] The average circularity of the toner particles is preferably 0.94 to 1.00, and more preferably 0.95 to 0.98.

[0112] The average circularity of toner particles is determined by (circular equivalent perimeter) / (perimeter) [(perimeter of a circle with the same projected area as the particle image) / (perimeter of the particle projection image)]. Specifically, it is a value measured by the following method. First, the toner particles to be measured are collected by suction, a flattened flow is formed, and a still image of the particles is captured by instantaneous strobe flashing. This particle image is then analyzed using a flow-type particle image analyzer (FPIA-3000 manufactured by Sysmex Corporation). The number of samples used to determine the average circularity is 3500. If the toner contains external additives, the toner (developer) to be measured is dispersed in water containing a surfactant, and then ultrasonic treatment is performed to obtain toner particles from which the external additives have been removed.

[0113] (External additive) Examples of external additives include inorganic particles. Examples of such inorganic particles include SiO2, TiO2, Al2O3, CuO, ZnO, SnO2, CeO2, Fe2O3, MgO, BaO, CaO, K2O, Na2O, ZrO2, CaO·SiO2, K2O·(TiO2)n, Al2O3·2SiO2, CaCO3, MgCO3, BaSO4, MgSO4, and the like.

[0114] The surface of the inorganic particles used as an external additive should preferably be hydrophobic. Hydrophobic treatment is carried out, for example, by immersing the inorganic particles in a hydrophobic agent. The hydrophobic agent is not particularly limited, but examples include silane-based coupling agents, silicone oil, titanate-based coupling agents, and aluminum-based coupling agents. These may be used individually or in combination of two or more. The amount of hydrophobic treatment agent is typically, for example, 1 to 10 parts by mass per 100 parts by mass of inorganic particles.

[0115] Examples of external additives include resin particles (such as polystyrene, polymethyl methacrylate (PMMA), and melamine resin), and cleaning activators (for example, metal salts of higher fatty acids represented by zinc stearate, and fluorine-based high molecular weight particles).

[0116] The amount of external additive added is preferably 0.01% by mass or more and 5% by mass or less relative to the toner particles, and more preferably 0.01% by mass or more and 2.0% by mass or less.

[0117] (Toner characteristics) - Viscoelastic properties of toner - As described above, the toner according to this embodiment is a specific toner. That is, D1(90), D50(90), D1(150), and D50(150) are all between 0.5 and 2.5, the value of D50(150)-D1(150) is less than 1.5, and the value of D50(90)-D1(90) is less than 1.0. In a specific toner, D1(90), D50(90), D1(150), and D50(150) are each between 0.5 and 2.5, preferably between 0.5 and 2.0, more preferably between 0.6 and 1.8, and even more preferably between 0.8 and 1.6. When D1(90), D50(90), D1(150), and D50(150) are all within the above range, better fixation is obtained compared to when they are smaller than the above range, and the difference in gloss conditions is reduced compared to when they are larger than the above range.

[0118] The value of D50(150)-D1(150) for a specific toner is less than 1.5, preferably 1.2 or less, and more preferably 1.0 or less. When the value of D50(150)-D1(150) is within the above range, the difference in glossiness conditions is reduced compared to when it is greater than the above range. From the viewpoint of reducing the difference in glossiness conditions, the smaller the value of D50(150)-D1(150), the better. Furthermore, there is no particular limit to the lower limit of the value of D50(150)-D1(150).

[0119] The D50(90)-D1(90) value for a specific toner is less than 1.0, preferably less than 0.5, more preferably 0.4 or less, and even more preferably 0.3 or less. When the D50(90)-D1(90) value is within the above range, the difference in glossiness conditions is reduced compared to when it is greater than the above range. From the viewpoint of reducing the difference in glossiness conditions, the smaller the D50(90)-D1(90) value, the better. Furthermore, there is no particular limit to the lower limit of the value of D50(90)-D1(90).

[0120] The storage modulus G' of the toner in the range of 30°C to 50°C is 1 × 10⁻⁶ 8 The Pa value is greater than or equal to the storage modulus G' of 1 × 10⁻⁶. 5 It is preferable that the temperature at which the storage modulus G' reaches less than Pa (i.e., the temperature at which the specific modulus is reached) is between 65°C and 90°C. Toners whose storage modulus G' satisfies the above conditions have a high modulus at low temperatures and a low modulus at temperatures between 65°C and 90°C. Therefore, when the storage modulus G' of the toner satisfies the above conditions, the storage modulus G' becomes 1 × 10⁻⁶. 5 Compared to cases where the temperature below Pa exceeds 90°C, heating makes the toner more easily melted, resulting in better fixation.

[0121] The storage modulus G' of toner at temperatures between 30°C and 50°C is 1 × 10⁻⁶ 8 Preferably Pa or higher, 1 × 10 8 Pa or more 1×10 9 It is more preferable that it be Pa, 2 × 10 8 Pa or more 6×10 8 It is even more preferable that it be Pa or less. When the storage modulus G' of the toner at temperatures between 30°C and 50°C is within the above range, the storage stability of the toner is better compared to when it is lower than the above range, and better fixing performance is more easily obtained compared to when it is higher than the above range.

[0122] Furthermore, the temperature at which the specific elastic modulus of the toner is reached is preferably 65°C to 90°C, more preferably 70°C to 87°C, and even more preferably 75°C to 84°C. Because the temperature at which the specific elastic modulus of the toner is reached is within the above range, the storage stability of the toner is better compared to when it is below this range, and better fixing performance is more easily obtained compared to when it is above this range.

[0123] The storage modulus G' and the temperature at which the toner reaches its specific modulus are determined as follows. Specifically, the toner to be measured is molded into a tablet shape using a press molding machine at room temperature (25°C) to prepare a sample for measurement. Then, the obtained sample is sandwiched between 8 mm diameter parallel plates, and dynamic viscoelasticity measurements are performed under the following conditions, with the measurement temperature increased from 30°C to 150°C at a rate of 2°C / min while maintaining a strain of 0.1 to 100%. The results obtained from the measurement are... The storage modulus G' is determined from the curves of the storage modulus and the loss modulus. -Measurement conditions- Measuring device: Rheometer ARES-G2 (manufactured by T.A. Instruments Co., Ltd.) Measuring jig: 8mm parallel plate Gap: Adjusted to 3mm Frequency: 1Hz

[0124] (Toner manufacturing method) Next, a description of the toner manufacturing method according to this embodiment will be given. The toner according to this embodiment is obtained by manufacturing toner particles and then, if necessary, adding an external additive to the toner particles.

[0125] Toner particles may be manufactured by either a dry process (e.g., kneading and grinding method) or a wet process (e.g., agglomeration, suspension polymerization, dissolution and suspension method). There are no particular restrictions on the manufacturing method of toner particles, and any well-known method may be used. Among these methods, obtaining toner particles by the aggregation and coalescence method is preferable.

[0126] Specifically, for example, when manufacturing toner particles by an aggregation and coalescence method, Toner particles are manufactured through the following steps: a resin particle dispersion in which resin particles that will become a binder are dispersed, and a specific resin particle dispersion in which specific resin particles will become specific resin particles (resin particle dispersion preparation step); a step of agglomerating resin particles (and other particles as needed) in the resin particle dispersion (and in the dispersion after mixing with other particle dispersions as needed) to form aggregated particles (aggregated particle formation step); and a step of heating the aggregated particle dispersion in which the aggregated particles are dispersed to fuse and combine the aggregated particles to form toner particles (fusion and combination step).

[0127] The details of each step are explained below. The following explanation describes a method for obtaining toner particles containing a colorant and a release agent, but the colorant and release agent are used only as needed. Of course, other additives besides colorants and release agents may also be used.

[0128] -Resin particle dispersion preparation process- First, a resin particle dispersion containing resin particles that will act as a binder is prepared, along with, for example, a coloring agent particle dispersion containing coloring agent particles and a release agent particle dispersion containing release agent particles.

[0129] Here, the resin particle dispersion is prepared, for example, by dispersing resin particles in a dispersion medium with a surfactant.

[0130] Examples of dispersion media used in resin particle dispersions include aqueous media. Examples of aqueous media include water such as distilled water and deionized water, and alcohols. These may be used individually or in combination of two or more.

[0131] Examples of surfactants include anionic surfactants such as sulfate esters, sulfonates, phosphates, and soaps; cationic surfactants such as amine salts and quaternary ammonium salts; and nonionic surfactants such as polyethylene glycol, alkylphenol ethylene oxide adducts, and polyhydric alcohols. Among these, anionic surfactants and cationic surfactants are particularly noteworthy. Nonionic surfactants may be used in combination with anionic or cationic surfactants. Surfactants may be used individually or in combination of two or more types.

[0132] In resin particle dispersions, common dispersion methods for dispersing resin particles in a dispersion medium include, for example, rotary shear homogenizers, ball mills with media, sand mills, and dyno mills. Depending on the type of resin particles, the resin particles may also be dispersed in the resin particle dispersion using, for example, a phase inversion emulsification method. Phase inversion emulsification is a method in which the resin to be dispersed is dissolved in a hydrophobic organic solvent in which the resin is soluble, a base is added to the organic continuous phase (O phase) to neutralize it, and then an aqueous medium (W phase) is added. This causes a conversion of the resin from W / O to O / W (so-called phase inversion), resulting in a discontinuous phase, and the resin is dispersed in the aqueous medium in particulate form.

[0133] The volume-average particle size of the resin particles dispersed in the resin particle dispersion is preferably 0.01 μm or more and 1 μm or less, more preferably 0.08 μm or more and 0.8 μm or less, and even more preferably 0.1 μm or more and 0.6 μm or less. The volume-average particle size of the resin particles is measured using a laser diffraction particle size distribution analyzer (e.g., LA-700, manufactured by Horiba, Ltd.). The particle size distribution is obtained by subtracting the cumulative distribution from the smallest particle size side for each divided particle size range (channel), and the particle size that accounts for 50% of the total particle size is measured as the volume-average particle size D50v. The volume-average particle size of particles in other dispersions is measured in the same manner.

[0134] The resin particle content in the resin particle dispersion is preferably, for example, 5% by mass or more and 50% by mass or less, and more preferably 10% by mass or more and 40% by mass or less.

[0135] Furthermore, colorant particle dispersions and release agent particle dispersions are prepared in the same manner as resin particle dispersions. In other words, the volume average particle size, dispersion medium, dispersion method, and particle content of the resin particle dispersions are the same for colorant particles dispersed in colorant particle dispersions and release agent particles dispersed in release agent particle dispersions.

[0136] Preparation of a specific resin particle dispersion As a method for preparing a dispersion of specific resin particles, known methods such as emulsion polymerization, melt kneading using a Banbury mixer or kneader, suspension polymerization, and spray drying can be applied, but emulsion polymerization is preferred.

[0137] From the viewpoint of keeping the storage modulus G' and loss tangent tanδ of specific resin particles within a preferred range, it is preferable to use styrene-based monomers and (meth)acrylic acid-based monomers as monomers and polymerize them in the presence of a crosslinking agent. Furthermore, it is preferable to carry out multiple emulsion polymerization steps in the production of specific resin particles. The following provides a more detailed explanation of the manufacturing method for specific resin particles.

[0138] The method for preparing a dispersion of specific resin particles is: A step to obtain an emulsion containing monomers, a crosslinking agent, a surfactant, and water (emulsifier preparation step), The process involves adding a polymerization initiator to an emulsion and heating it to polymerize the monomer (first emulsion polymerization step), Preferably, the process includes a step (second emulsion polymerization step) in which an emulsion containing monomers and a crosslinking agent is added to the reaction solution after the first emulsion polymerization step, and the monomers are polymerized by heating.

[0139] -Emulsion preparation process- This is a process to obtain an emulsion containing monomers, a crosslinking agent, a surfactant, and water. It is preferable to obtain an emulsion by emulsifying the monomer, crosslinking agent, surfactant, and water using an emulsifier. Examples of emulsifiers include rotary stirrers equipped with propeller-type, anchor-type, paddle-type, or turbine-type stirring blades, static mixers such as static mixers, homogenizers, Examples include rotor / stator type emulsifiers such as Creamix, mill type emulsifiers with grinding functions, high-pressure emulsifiers such as Manton-Gorin type pressure emulsifiers, high-pressure nozzle type emulsifiers that generate cavitation under high pressure, high-pressure impact type emulsifiers such as microfluidizers that apply shear force by causing liquids to collide under high pressure, ultrasonic emulsifiers that generate cavitation with ultrasound, and membrane emulsifiers that perform uniform emulsification through pores.

[0140] It is preferable to use styrene-based monomers and (meth)acrylic acid-based monomers as monomers. The crosslinking agents described above are applicable.

[0141] Examples of surfactants include anionic surfactants such as sulfate esters, sulfonates, phosphates, and soaps; cationic surfactants such as amine salts and quaternary ammonium salts; and nonionic surfactants such as polyethylene glycol, alkylphenol ethylene oxide adducts, and polyhydric alcohols. Nonionic surfactants may be used in combination with anionic or cationic surfactants. Among these, anionic surfactants are preferred. Surfactants may be used individually or in combination of two or more.

[0142] The emulsified solution may contain a chain transfer agent. There are no particular restrictions on the chain transfer agent, but compounds having a thiol component can be used. Specifically, alkyl mercaptans such as hexyl mercaptan, heptyl mercaptan, octyl mercaptan, nonyl mercaptan, decyl mercaptan, and dodecyl mercaptan are preferred.

[0143] From the viewpoint of keeping the storage modulus G' and loss tangent tanδ of the specific resin particles within a preferred range, the mass ratio of styrene monomers and (meth)acrylic acid monomers in the emulsion (styrene monomers / (meth)acrylic acid monomers) is preferably 0.2 or more and 1.1 or less. Furthermore, from the viewpoint of keeping the storage modulus G' and loss tangent tanδ of the specific resin particles within a favorable range, it is preferable that the crosslinking agent content relative to the entire emulsion is 0.5% by mass or more and 3% by mass or less.

[0144] -First emulsion polymerization process- This process involves adding a polymerization initiator to an emulsified solution and heating it to polymerize the monomers. Here, during polymerization, it is preferable to stir the emulsion (reaction solution) containing the polymerization initiator with a stirrer. Examples of agitators include rotary agitators equipped with propeller-type, anchor-type, paddle-type, or turbine-type agitators. Ammonium persulfate is preferred as the polymerization initiator. Furthermore, when using polymerization initiators, the viscoelasticity of the resulting specific resin particles can be controlled by adjusting the amount of polymerization initiator added. For example, reducing the amount of polymerization initiator makes it easier to obtain resin particles with a high storage modulus G'.

[0145] -Second emulsion polymerization process- This step involves adding an emulsion containing monomers to the reaction solution after the first emulsion polymerization step and heating it to polymerize the monomers. During polymerization, it is preferable to stir the reaction solution in the same manner as in the first emulsion polymerization step. In this process, the viscoelasticity of the resulting specific resin particles may be controlled by adjusting the time spent adding the emulsion containing monomers. For example, increasing the time spent adding the emulsion containing monomers makes it easier to obtain resin particles with a high storage modulus G'. The time spent adding the emulsion containing monomers can be, for example, in the range of 2 hours to 5 hours. Furthermore, in this process, by adjusting the temperature when stirring the reaction solution, the specific resin obtained can be controlled. The viscoelasticity of the particles may be controlled. For example, lowering the temperature during stirring of the reaction solution makes it easier to obtain resin particles with a high storage modulus G'. Examples of temperatures for stirring the reaction solution include a range of 55°C to 75°C. For emulsions containing monomers, it is preferable to obtain the emulsion by emulsifying the monomer, surfactant, and water using an emulsifier.

[0146] -Agglomerated particle formation process- Next, the resin particle dispersion is mixed with the coloring agent particle dispersion, the mold release agent particle dispersion, and the specific resin particle dispersion. Then, in the mixed dispersion, the resin particles, colorant particles, release agent particles, and specific resin particles are heteroaggregated to form aggregated particles containing resin particles, colorant particles, release agent particles, and specific resin particles, which have a diameter close to the diameter of the target toner particles.

[0147] Specifically, for example, a coagulant is added to a mixed dispersion, the pH of the mixed dispersion is adjusted to be acidic (for example, pH 2 to 5), a dispersion stabilizer is added as needed, and then the mixture is heated to a temperature of the glass transition temperature of the resin particles (specifically, for example, above the glass transition temperature of the resin particles -30°C or below the glass transition temperature of -10°C) to agglomerate the particles dispersed in the mixed dispersion and form agglomerated particles. In the agglomerated particle formation step, for example, the mixed dispersion may be stirred in a rotary shear homogenizer, the above-mentioned flocculant may be added at room temperature (e.g., 25°C), the pH of the mixed dispersion may be adjusted to acidic (e.g., pH 2 to 5), a dispersion stabilizer may be added as needed, and then the above-mentioned heating may be performed.

[0148] In this process, the dispersion state of specific resin particles in the resulting toner particles may be controlled by adjusting the temperature of the mixed dispersion when adding the flocculant. For example, lowering the temperature of the mixed dispersion improves the dispersibility of the specific resin particles. Examples of suitable temperatures for the mixed dispersion include a range of 5°C to 40°C. Furthermore, in this process, the dispersion state of specific resin particles in the resulting toner particles may be controlled by adjusting the stirring speed after the addition of the flocculant. For example, increasing the stirring speed after the addition of the flocculant improves the dispersibility of the specific resin particles.

[0149] Examples of flocculants include surfactants with opposite polarity to the surfactant used as a dispersant added to a mixed dispersion, inorganic metal salts, and metal complexes with a valency of 2 or higher. In particular, when a metal complex is used as a flocculant, the amount of surfactant used is reduced and the electrostatic properties are improved. Additives that form complexes or similar bonds with the metal ions of the flocculant may be used as needed. Chelating agents are preferably used as such additives.

[0150] Examples of inorganic metal salts include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate, as well as inorganic metal salt polymers such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. As a chelating agent, a water-soluble chelating agent may be used. Examples of chelating agents include oxycarboxylic acids such as tartaric acid, citric acid, and gluconic acid, as well as iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), and ethylenediaminetetraacetic acid (EDTA). The amount of chelating agent to be added is preferably 0.01 parts by mass or more and 5.0 parts by mass or less per 100 parts by mass of resin particles, and more preferably 0.1 parts by mass or more and less than 3.0 parts by mass.

[0151] -Fusion / unification process- Next, the dispersion of aggregated particles is heated to, for example, a temperature above the glass transition temperature of the resin particles (for example, a temperature 10 to 30°C higher than the glass transition temperature of the resin particles). Then, the aggregated particles fuse and combine to form toner particles.

[0152] Toner particles are obtained through the above process. Furthermore, after obtaining an aggregated particle dispersion in which aggregated particles are dispersed, toner particles may be manufactured by further mixing the aggregated particle dispersion, a resin particle dispersion in which resin particles are dispersed, and a specific resin particle dispersion in which specific resin particles are dispersed, and agglomerating the aggregated particles so that the resin particles and specific resin particles adhere to the surface of the aggregated particles to form second aggregated particles; and heating the second aggregated particle dispersion in which the second aggregated particles are dispersed to fuse and combine the second aggregated particles to form toner particles with a core / shell structure.

[0153] In the step of forming the second aggregated particles, the addition of the resin particle dispersion and the specific resin particle dispersion, and the attachment of the resin particles and specific resin particles to the surface of the aggregated particles may be repeated multiple times. By repeating this process multiple times, toner particles can be obtained in which the specific resin particles are evenly distributed in both the surface and central regions of the toner particles.

[0154] After the fusion and combination process is complete, the toner particles formed in the solution are subjected to known washing, solid-liquid separation, and drying processes to obtain dried toner particles. The washing process should be thoroughly performed using ion-exchanged water for displacement washing, considering the electrostatic charge. The solid-liquid separation process is not particularly restricted, but suction filtration, pressure filtration, etc., are preferable for productivity. The drying process is also not particularly restricted, but freeze-drying, air-flow drying, fluidized bed drying, vibratory fluidized bed drying, etc., are preferable for productivity.

[0155] The toner according to this embodiment is manufactured, for example, by adding an external additive to the obtained dried toner particles and mixing them. Mixing can be performed using, for example, a V-blender, a Henschel mixer, a Redigge mixer, etc. Furthermore, if necessary, coarse particles of the toner may be removed using a vibrating screen separator, a wind screen separator, etc.

[0156] <Electrostatic Image Developer> The electrostatic image developer according to this embodiment includes at least the toner according to this embodiment. The electrostatic image developer according to this embodiment may be a one-component developer containing only the toner according to this embodiment, or it may be a two-component developer mixed with the toner and a carrier.

[0157] There are no particular restrictions on the carriers, and known carriers can be used. Examples of carriers include coated carriers in which a coating resin is applied to the surface of a core material made of magnetic powder; magnetic powder dispersed carriers in which magnetic powder is dispersed and blended in a matrix resin; and resin-impregnated carriers in which resin is impregnated into porous magnetic powder. Furthermore, magnetic powder dispersed carriers and resin-impregnated carriers may be carriers in which the constituent particles of the carrier are used as a core material and coated with a coating resin.

[0158] Examples of magnetic powders include magnetic metals such as iron, nickel, and cobalt, and magnetic oxides such as ferrite and magnetite.

[0159] Examples of coating resins and matrix resins include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic acid ester copolymer, straight silicone resin or modified thereof containing organosiloxane bonds, fluororesin, polyester, polycarbonate, phenolic resin, epoxy resin, and the like. Furthermore, the coating resin and matrix resin contain conductive particles and other additives. That's good too. Examples of conductive particles include metals such as gold, silver, and copper, as well as carbon black, titanium oxide, zinc oxide, tin oxide, barium sulfate, aluminum borate, and potassium titanate.

[0160] To coat the surface of the core material with a coating resin, one method is to coat it with a coating layer-forming solution prepared by dissolving the coating resin and, if necessary, various additives in a suitable solvent. The solvent is not particularly limited and should be selected considering the coating resin used, its suitability for coating, etc. Specific resin coating methods include the immersion method, in which the core material is immersed in a coating layer forming solution; the spray method, in which the coating layer forming solution is sprayed onto the surface of the core material; the fluidized bed method, in which the coating layer forming solution is sprayed onto the core material while it is suspended by fluidized air; and the kneader coater method, in which the carrier core material and the coating layer forming solution are mixed in a kneader coater and the solvent is removed.

[0161] In a two-component developer, the mixing ratio (mass ratio) of toner and carrier is preferably toner:carrier = 1:100 to 30:100, and more preferably 3:100 to 20:100.

[0162] <Image forming device / image forming method> An image forming apparatus / image forming method according to this embodiment will be described. The image forming apparatus according to this embodiment comprises an image holder, a charging means for charging the surface of the image holder, an electrostatic image forming means for forming an electrostatic image on the charged surface of the image holder, a developing means for containing an electrostatic image developer and developing the electrostatic image formed on the surface of the image holder as a toner image using the electrostatic image developer, a transfer means for transferring the toner image formed on the surface of the image holder to the surface of a recording medium, and a fixing means for fixing the toner image transferred to the surface of the recording medium. The electrostatic image developer according to this embodiment is applied as the electrostatic image developer.

[0163] The image forming apparatus according to this embodiment implements an image forming method (image forming method according to this embodiment) comprising: a charging step of charging the surface of an image holder; an electrostatic image forming step of forming an electrostatic image on the charged surface of the image holder; a developing step of developing the electrostatic image formed on the surface of the image holder as a toner image using an electrostatic image developer according to this embodiment; a transfer step of transferring the toner image formed on the surface of the image holder to the surface of a recording medium; and a fixing step of fixing the toner image transferred to the surface of the recording medium.

[0164] The image forming apparatus according to this embodiment may be a direct transfer type apparatus that directly transfers a toner image formed on the surface of an image holder to a recording medium; an intermediate transfer type apparatus that first transfers a toner image formed on the surface of an image holder to the surface of an intermediate transfer body, and secondarily transfers the toner image transferred to the surface of the intermediate transfer body to the surface of a recording medium; an apparatus equipped with cleaning means for cleaning the surface of the image holder before charging after the transfer of the toner image; or an apparatus equipped with static elimination means for irradiating the surface of the image holder with static elimination light before charging after the transfer of the toner image. In the case of an intermediate transfer method apparatus, the transfer means may include, for example, an intermediate transfer body on which a toner image is transferred; a primary transfer means for primaryly transferring the toner image formed on the surface of the image holder to the surface of the intermediate transfer body; and a secondary transfer means for secondary transferring the toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium.

[0165] In the image forming apparatus according to this embodiment, for example, the part including the developing means may be a cartridge structure (process cartridge) that can be attached to and detached from the image forming apparatus. As the process cartridge, for example, a process cartridge equipped with a developing means containing the electrostatic image developer according to this embodiment is preferably used.

[0166] The following is an example of an image forming apparatus according to this embodiment, but it is not limited to this example. The main parts shown in the figure will be described, and other parts will be omitted from the explanation.

[0167] Figure 1 is a schematic diagram showing the image forming apparatus according to this embodiment. The image forming apparatus shown in Figure 1 is equipped with first to fourth electrophotographic image forming units 10Y, 10M, 10C, and 10K (image forming means) that output images of yellow (Y), magenta (M), cyan (C), and black (K) based on color-separated image data. These image forming units (hereinafter sometimes simply referred to as "units") 10Y, 10M, 10C, and 10K are arranged side by side at predetermined distances from each other in the horizontal direction. These units 10Y, 10M, 10C, and 10K may also be process cartridges that can be attached to and detached from the image forming apparatus.

[0168] In the drawings of each unit 10Y, 10M, 10C, and 10K, an intermediate transfer belt 20 is extended through each unit as an intermediate transfer body. The intermediate transfer belt 20 is wound around drive rolls 22 and support rolls 24 that are spaced apart from each other from left to right in the drawing and are in contact with the inner surface of the intermediate transfer belt 20, and is configured to travel in the direction from the first unit 10Y to the fourth unit 10K. The support rolls 24 are subjected to a force that moves away from the drive rolls 22 by a spring or the like (not shown), and tension is applied to the intermediate transfer belt 20 wound around both. In addition, an intermediate transfer body cleaning device 30 is provided on the side of the image holder of the intermediate transfer belt 20, facing the drive rolls 22. Furthermore, each of the developing devices (developing means) 4Y, 4M, 4C, and 4K for each unit 10Y, 10M, 10C, and 10K is supplied with toner containing four colors of toner: yellow, magenta, cyan, and black, contained in toner cartridges 8Y, 8M, 8C, and 8K.

[0169] Since the first to fourth units 10Y, 10M, 10C, and 10K have equivalent configurations, the first unit 10Y, which forms the yellow image and is located on the upstream side in the direction of travel of the intermediate transfer belt, will be described as a representative example. The descriptions of the second to fourth units 10M, 10C, and 10K will be omitted by assigning reference numerals to parts equivalent to the first unit 10Y, with magenta (M), cyan (C), and black (K) instead of yellow (Y).

[0170] The first unit 10Y has a photoreceptor 1Y that acts as an image holder. Around the photoreceptor 1Y are, in order, a charging roll (an example of a charging means) 2Y that charges the surface of the photoreceptor 1Y to a predetermined potential, an exposure device (an example of a charge image forming means) 3 that exposes the charged surface with a laser beam 3Y based on a color-separated image signal to form a charge image, a developing device (an example of a developing means) 4Y that supplies charged toner to the charge image to develop the charge image, a primary transfer roll 5Y (an example of a primary transfer means) that transfers the developed toner image onto an intermediate transfer belt 20, and a photoreceptor cleaning device (an example of a cleaning means) 6Y that removes toner remaining on the surface of the photoreceptor 1Y after primary transfer. The primary transfer roll 5Y is positioned inside the intermediate transfer belt 20, facing the photoreceptor 1Y. Furthermore, each of the primary transfer rolls 5Y, 5M, 5C, and 5K is connected to a bias power supply (not shown) that applies a primary transfer bias. Each bias power supply varies the transfer bias applied to each primary transfer roll through control by a control unit (not shown).

[0171] The following describes the process of forming the yellow image in the first unit 10Y. First, prior to operation, the surface of the photoreceptor 1Y is charged to a potential of -600V to -800V by the charging roll 2Y. The photoreceptor 1Y is conductive (e.g., volume resistivity at 20°C: 1 × 10⁻⁶). -6The photosensitive layer is formed by laminating a photosensitive layer on a substrate (less than Ωcm). This photosensitive layer normally has high resistance (resistance of general resin), but when irradiated with a laser beam 3Y, the resistivity of the irradiated area changes. Therefore, a laser beam 3Y is output to the surface of the charged photoreceptor 1Y via the exposure device 3 according to image data for yellow sent from a control unit (not shown). The laser beam 3Y irradiates the photosensitive layer on the surface of the photoreceptor 1Y, thereby forming an electrostatic image of the yellow image pattern on the surface of the photoreceptor 1Y.

[0172] A static charge image is an image formed on the surface of a photoreceptor 1Y due to charging. It is a so-called negative latent image formed when the resistivity of the irradiated portion of the photoreceptor layer decreases due to the laser beam 3Y, causing the charged material on the surface of the photoreceptor 1Y to flow, while the charge remains in the portion not irradiated by the laser beam 3Y. The electrostatic charge image formed on the photoreceptor 1Y is rotated to a predetermined development position as the photoreceptor 1Y moves. At this development position, the electrostatic charge image on the photoreceptor 1Y is made visible as a toner image (developed image) by the developing device 4Y.

[0173] The developing device 4Y contains, for example, an electrostatic image developer including at least yellow toner and a carrier. The yellow toner is triboelectrically charged by being agitated inside the developing device 4Y and is held on the developer roll (an example of a developer holder) with a charge of the same polarity (negative polarity) as the static charge on the photoreceptor 1Y. As the surface of the photoreceptor 1Y passes through the developing device 4Y, the yellow toner electrostatically adheres to the discharged latent image on the surface of the photoreceptor 1Y, and the latent image is developed by the yellow toner. The photoreceptor 1Y, on which the yellow toner image has been formed, continues to move at a predetermined speed, and the toner image developed on the photoreceptor 1Y is transported to a predetermined primary transfer position.

[0174] When the yellow toner image on the photoreceptor 1Y is conveyed to the primary transfer position, a primary transfer bias is applied to the primary transfer roll 5Y, and an electrostatic force directed from the photoreceptor 1Y toward the primary transfer roll 5Y acts on the toner image, causing the toner image on the photoreceptor 1Y to be transferred onto the intermediate transfer belt 20. The transfer bias applied at this time has a polarity (+) opposite to the polarity (-) of the toner. For example, in the first unit 10Y, it is controlled to +10 μA by a control unit (not shown). On the other hand, the toner remaining on the photoreceptor 1Y is removed and recovered by the photoreceptor cleaning device 6Y.

[0175] Also, the primary transfer biases applied to the primary transfer rolls 5M, 5C, and 5K after the second unit 10M are also controlled in accordance with the first unit. Thus, the intermediate transfer belt 20 onto which the yellow toner image has been transferred in the first unit 10Y is sequentially conveyed through the second to fourth units 10M, 10C, and 10K, and the toner images of each color are overlapped and multi-transferred.

[0176] The intermediate transfer belt 20 onto which the four-color toner images have been multi-transferred through the first to fourth units reaches a secondary transfer section composed of the intermediate transfer belt 20, a support roll 24 in contact with the inner surface of the intermediate transfer belt, and a secondary transfer roll (an example of secondary transfer means) 26 disposed on the image holding surface side of the intermediate transfer belt 20. On the other hand, the recording paper (an example of a recording medium) P is fed at a predetermined timing into the gap where the secondary transfer roll 26 and the intermediate transfer belt 20 are in contact via a feeding mechanism, and a secondary transfer bias is applied to the support roll 24. The transfer bias applied at this time has the same polarity (-) as the polarity (-) of the toner, and an electrostatic force directed from the intermediate transfer belt 20 toward the recording paper P acts on the toner image, causing the toner image on the intermediate transfer belt 20 to be transferred onto the recording paper P. The secondary transfer bias at this time is determined according to the resistance detected by a resistance detection means (not shown) for detecting the resistance of the secondary transfer section and is voltage-controlled.

[0177] Thereafter, the recording paper P is fed into the pressure contact portion (nip portion) of a pair of fixing rolls in the fixing device (an example of the fixing means) 28, and the toner image is fixed onto the recording paper P, thereby forming a fixed image.

[0178] Examples of the recording paper P for transferring the toner image include plain paper used in electrophotographic copiers, printers, etc. Recording media other than the recording paper P also include OHP sheets, etc. In order to further improve the smoothness of the image surface after fixing, the surface of the recording paper P is preferably smooth. For example, coated paper obtained by coating the surface of plain paper with resin or the like, art paper for printing, etc. are preferably used.

[0179] The recording paper P on which the fixing of the color image has been completed is carried out toward the discharge portion, and a series of color image forming operations are terminated.

[0180] <Process cartridge / Toner cartridge> The process cartridge according to the present embodiment will be described. The process cartridge according to the present embodiment houses the electrostatic charge image developer according to the present embodiment, and includes developing means for developing the electrostatic charge image formed on the surface of the image carrier as a toner image, and is a process cartridge that is detachable from the image forming apparatus.

[0181] Note that the process cartridge according to the present embodiment is not limited to the above configuration, and may be configured to include a developing device and at least one selected from other means such as an image carrier, charging means, electrostatic charge image forming means, and transfer means, etc., as necessary.

[0182] Hereinafter, an example of the process cartridge according to the present embodiment will be shown, but it is not limited thereto. Note that the main parts shown in the figure will be described, and the description of the others will be omitted.

[0183] FIG. 2 is a schematic configuration diagram showing the process cartridge according to the present embodiment. The process cartridge 200 shown in Figure 2 is constructed by integrally holding a photoreceptor 107 (an example of an image holder), a charging roll 108 (an example of a charging means) provided around the photoreceptor 107, a developing device 111 (an example of a developing means), and a photoreceptor cleaning device 113 (an example of a cleaning means) within a housing 117 equipped with a mounting rail 116 and an opening 118 for exposure, and is then formed into a cartridge. In Figure 2, 109 represents an exposure apparatus (an example of electrostatic image formation means), 112 represents a transfer apparatus (an example of a transfer means), 115 represents a fixing apparatus (an example of a fixing means), and 300 represents recording paper (an example of a recording medium).

[0184] Next, the toner cartridge according to this embodiment will be described. The toner cartridge according to this embodiment is a toner cartridge that contains the toner according to this embodiment and is attached to and detached from an image forming apparatus. The toner cartridge contains replenishment toner for supply to a developing means provided within the image forming apparatus.

[0185] The image forming apparatus shown in Figure 1 is an image forming apparatus with removable toner cartridges 8Y, 8M, 8C, and 8K. The developing units 4Y, 4M, 4C, and 4K are connected to toner cartridges corresponding to each developing unit (color) by toner supply pipes (not shown). When the toner contained in a toner cartridge becomes low, the toner cartridge is replaced. [Examples]

[0186] Examples are described below, but the present invention is not limited to these examples. In the following description, unless otherwise specified, "parts" and "%" all refer to mass.

[0187] [Preparation of specific resin particle dispersion and comparative resin particle dispersion] <Preparation of Specific Resin Particle Dispersion 1> Styrene: 47.9 parts • n-butyl acrylate: 51.8 parts • 2-carboxyethyl acrylate: 0.3 parts • Anionic surfactant (Dow Chemical, Dowfax 2A1): 0.8 parts • 1,10-Decanediol diacrylate: 1.65 parts The above raw materials were mixed and dissolved, and 60 parts of ion-exchanged water were added to disperse and emulsify in a flask to prepare an emulsion. Next, 1.3 parts of anionic surfactant (Dowfax 2A1, manufactured by Dow Chemical) were dissolved in 90 parts of deionized water, 1 part of the emulsion was added to it, and then 10 parts of deionized water in which 5.4 parts of ammonium persulfate was dissolved was added. Subsequently, the remaining emulsion was added over 180 minutes, and the flask was purged with nitrogen. The solution in the flask was then heated in an oil bath to 65°C while stirring, and emulsion polymerization was continued for 500 minutes to obtain a specific resin particle dispersion 1 with a solid content of 24.5% by mass.

[0188] <Preparation of specific resin particle dispersions 2-14 and C1-C2> Except for the amounts of styrene added, n-butyl acrylate added, acrylic acid added, 2-carboxyethyl acrylate added, total amount of anionic surfactant added, amount of crosslinking agent added, type of crosslinking agent (crosslinking agent type in the table), amount of ammonium peroxide added, temperature when heated in the oil bath (polymerization temperature in the table), time when the remaining emulsion was added (addition time in the table), and time when emulsion polymerization was continued after heating (holding time in the table), specific resin particle dispersions 2 to 14 and C1 to C2 were obtained in the same manner as specific resin particle dispersion 1. Table 1 also shows the number of carbon atoms in the alkylene chain of the added crosslinking agent (the number of carbon atoms in the table).

[0189] [Table 1]

[0190] For the resin particles contained in the obtained specific resin particle dispersion and the comparative resin particle dispersion, the glass transition temperature Tg (\"Tg\" in the table) determined from dynamic viscoelasticity measurement, the minimum value (\"G’(small) 90~150°C\" in the table) and the maximum value (\"G’(large) 90~150°C\") of the storage modulus G’ (p90-150) at 90°C or higher and 150°C or lower, the minimum value (\"tanδ(small)\" in the table) and the maximum value (\"tanδ(large)\" in the table) of the loss tangent tanδ in the range of 30°C or higher and 150°C or lower, the minimum value (\"tanδ small 65~150°C\" in the table) and the maximum value (\"tanδ large 65~150°C\") of the loss tangent tanδ in the range of 65°C or higher and 150°C or lower, the number average particle diameter (\"number average diameter\" in the table), and the SP value (S), the results obtained by the above-mentioned method are shown in Table 2.

[0191]

Table 2

[0192] <Preparation of Amorphous Resin Particle Dispersion 1> · Terephthalic acid: 28 parts · Fumaric acid: 164 parts · Adipic acid: 10 parts · Bisphenol A ethylene oxide 2 mol adduct: 26 parts · Bisphenol A propylene oxide 2 mol adduct: 542 parts The above materials were charged into a reaction vessel equipped with a stirring device, a nitrogen inlet tube, a temperature sensor and a rectification column, the temperature was raised to 190°C over 1 hour, and 1.2 parts of dibutyltin oxide was added to 100 parts of the above materials. While distilling off the generated water, the temperature was raised to 240°C over 6 hours, and after maintaining at 240°C and continuing the dehydration condensation reaction for 3 hours, the reaction product was cooled.

[0193] While the reaction product was in a molten state, it was transferred to a Cavitron CD101 (manufactured by Eurotech) at a rate of 100 g per minute. At the same time, separately prepared ammonia water with a concentration of 0.37% by mass was transferred to the Cavitron CD101 at a rate of 0.1 liter per minute while heating it to 120°C with a heat exchanger. The rotational speed of the rotor was 60 Hz, and the pressure was 5 kg / cm2 The Cavitron CD1010 was operated under the specified conditions to obtain a resin particle dispersion containing amorphous polyester resin particles with a volume-average particle size of 169 nm. Ion-exchanged water was added to the resin particle dispersion to adjust the solid content to 20% by mass to obtain amorphous resin particle dispersion 1. The obtained amorphous polyester resin had an SP value (R) of 9.41.

[0194] <Preparation of amorphous resin particle dispersion 2> Styrene: 72 units n-butyl acrylate: 27 parts • 2-carboxyethyl acrylate: 1.3 parts Dodecanethiol: Part 2 The mixture obtained by mixing and dissolving the above materials is an anionic surfactant (TaycaPowe r (manufactured by Teika Co., Ltd.) was dissolved in 100 parts by mass of ion-exchanged water to form a surfactant solution, which was then dispersed and emulsified in a flask. Next, while stirring the flask, an aqueous solution of 6 parts by mass of ammonium persulfate dissolved in 50 parts by mass of ion-exchanged water was added over 20 minutes. After purging with nitrogen, the contents of the flask were heated in an oil bath while stirring until they reached 75°C, and emulsion polymerization was continued by maintaining the temperature at 75°C for 4 hours. In this way, a resin particle dispersion was obtained in which amorphous styrene acrylic resin particles with a volume-average particle size of 160 nm and a weight-average molecular weight of 56000 were dispersed. Ion-exchanged water was added to this resin particle dispersion to adjust the solid content to 31.4% by mass to obtain amorphous resin particle dispersion 2. The obtained amorphous styrene-acrylic resin had an SP value (R) of 9.14.

[0195] <Preparation of amorphous resin particle dispersion 3> Terephthalic acid: 28 parts • Fumaric acid: 174 parts • Bisphenol A ethylene oxide 2 molar adduct: 26 parts • Bisphenol A propylene oxide 2 molar adduct: 542 parts The above materials were placed in a reaction vessel equipped with a stirrer, nitrogen inlet tube, temperature sensor, and rectification column. The temperature was raised to 190°C over 1 hour, and 1.2 parts of dibutyltin oxide were added for every 100 parts of the above materials. The temperature was raised to 240°C over 6 hours while distilling off the generated water, and the dehydration condensation reaction was continued at 240°C for 3 hours, after which the reaction product was cooled.

[0196] The reaction product was transferred in a molten state to a Cavitron CD1010 (manufactured by Eurotech) at a rate of 100 g per minute. Simultaneously, a separately prepared 0.37 mass% ammonia solution was transferred to the Cavitron CD1010 at a rate of 0.1 liters per minute while being heated to 120°C in a heat exchanger. The Cavitron CD1010 was operated under conditions of a rotor rotation speed of 60 Hz and a pressure of 5 kg / cm² to obtain a resin particle dispersion containing amorphous polyester resin particles with a volume-average particle size of 175 nm. Ion-exchanged water was added to the resin particle dispersion to adjust the solid content to 20 mass%, resulting in amorphous resin particle dispersion 3. The obtained amorphous polyester resin had an SP value (R) of 9.43.

[0197] <Preparation of crystalline resin particle dispersion> • 1,10-Dodecanedioic acid: 225 parts • 1,6-Hexanediol: 143 parts The above materials were placed in a reaction vessel equipped with a stirrer, nitrogen inlet tube, temperature sensor, and rectification column. The temperature was raised to 160°C over 1 hour, and 0.8 parts by mass of dibutyltin oxide were added. The temperature was raised to 180°C over 6 hours while distilling off the generated water, and the dehydration condensation reaction was continued at 180°C for 5 hours. After that, the temperature was gradually raised to 230°C under reduced pressure, and the mixture was stirred at 230°C for 2 hours. The reaction mixture was then cooled. After cooling, solid-liquid separation was performed, and the solid was dried to obtain a crystalline polyester resin.

[0198] • Crystalline polyester resin: 100 units • Methyl ethyl ketone: 40 parts • Isopropyl alcohol: 30 parts • 10% ammonia aqueous solution: 6 parts The above materials were added to a 3-liter jacketed reaction vessel (Tokyo Rikakikai Co., Ltd.: BJ-30N) equipped with a condenser, thermometer, water dropper, and anchor vanes. The resin was dissolved while stirring at 100 rpm in a water-circulating constant-temperature bath, maintaining the temperature at 80°C. Subsequently, the water-circulating constant-temperature bath was set to 50°C, and 400 parts of ion-exchanged water, kept at 50°C, were added dropwise at a rate of 7 parts by mass / min to invert the phase and obtain an emulsion. 576 parts by mass of the obtained emulsion and 500 parts by mass of ion-exchanged water were placed in a 2-liter round-bottom flask and set in an evaporator (Tokyo Rikakikai Co., Ltd.) equipped with a vacuum control unit via a trap bulb. The flask was heated in a 60°C water bath while rotating, and the solvent was removed by reducing the pressure to 7 kPa while taking care to prevent bumping. The volume-average particle size D50v of the resin particles in this dispersion was 185 nm. Subsequently, deionized water was added to obtain a dispersion of crystalline resin particles with a solid content concentration of 22.1% by mass.

[0199] <Preparation of colorant dispersion> • Cyan pigment (manufactured by Dainichi Seika Co., Ltd., Pigment Blue 15:3 (copper phthalocyanine)): 98 parts • Anionic surfactant (TaycaPower, manufactured by Teika Co., Ltd.): 2 parts • Ion-exchanged water: 420 units The above ingredients were mixed and dissolved, and dispersed for 10 minutes using a homogenizer (IKA Ultra-Turrax) to obtain a colorant dispersion with a median particle size of 164 nm and a solid content of 21.1% by mass.

[0200] <Preparation of mold release agent dispersion> • Synthetic wax (manufactured by Nippon Seiro Co., Ltd., FNP92, melting point Tw: 92℃): 50 units • Anionic surfactant (TaycaPower, manufactured by Teika Co., Ltd.): 1 part • Ion-exchanged water: 200 bottles The above materials were mixed and heated to 130°C, dispersed using a homogenizer (IKA Ultra-Turrax T50), and then heated in a Manton-Gorin high-pressure homogenizer (Gorin). The release agent particles were dispersed using a dispersion treatment to obtain a release agent dispersion (solid content 20% by mass). The volume-average particle size of the release agent particles was 214 nm.

[0201] <Example 1> ·Amorphous resin particle dispersion 1: 169 parts ·Specified resin particle dispersion liquid 1: 33 parts ·Crystalline resin particle dispersion: 53 parts • Release agent dispersion: 25 parts • Colorant dispersion: 33 parts • Anionic surfactant (Dow Chemical, Dowfax 2A1): 4.8 parts The above raw materials, whose liquid temperature was adjusted to 10°C, were placed in a 3L cylindrical stainless steel container and mixed by dispersing them for 2 minutes while applying shear force at 4000 rpm using a homogenizer (IKA Ultra-Turrax T50). Next, 1.75 parts of a 10% aqueous solution of aluminum sulfate in nitric acid was gradually added dropwise as a flocculant, and the mixture was dispersed and mixed for 10 minutes at a homogenizer rotation speed of 10,000 rpm to obtain the raw material dispersion.

[0202] Subsequently, the raw material dispersion was transferred to a polymerization vessel equipped with a stirring device using two paddle blades and a thermometer. The stirring speed was set to 550 rpm and heating was started with a mantle heater to promote the growth of aggregated particles at 40°C. At this time, the pH of the raw material dispersion was controlled to a range of 2.2 to 3.5 using 0.3 M nitric acid and 1 M sodium hydroxide aqueous solution. The mixture was maintained within this pH range for about 2 hours to form aggregated particles. Next, a dispersion prepared by mixing 1:21 parts amorphous resin particle dispersion and 1:8 parts specific resin particle dispersion was added, and the mixture was held for 60 minutes to allow the binder resin particles and specific resin particles to adhere to the surface of the aggregated particles. The temperature was then raised to 53°C, and then 1:21 parts amorphous resin particle dispersion was added, and the mixture was held for 60 minutes to allow the binder resin particles to adhere to the surface of the aggregated particles.

[0203] The aggregated particles were sorted while checking their size and morphology using an optical microscope and a multisizer 3. Then, the pH was adjusted to 7.8 using a 5% sodium hydroxide aqueous solution and held for 15 minutes. Subsequently, the pH was raised to 8.0 to fuse the aggregated particles, and then the temperature was increased to 85°C. After confirming the fusion of the aggregated particles using an optical microscope, heating was stopped after 2 hours, and the mixture was cooled at a rate of 1.0°C / min. The mixture was then sieved with a 20 μm mesh, washed repeatedly with water, and dried in a vacuum dryer to obtain toner particles 1 with a volume-average particle size of 5.3 μm.

[0204] 100 parts of the obtained toner particles and 0.7 parts of dimethyl silicone oil-treated silica particles (RY200, manufactured by Nippon Aerosil Co., Ltd.) were mixed in a Henschel mixer to obtain toner 1.

[0205] <Examples 2-11, Examples 29-32, and Comparative Examples C1-C2> Toners 2-11, 29-32, and C1-C2 were obtained in the same manner as Toner 1, except that instead of Specific Resin Particle Dispersion 1, a Specific Resin Particle Dispersion or Comparative Resin Particle Dispersion of the types shown in Table 3 was used in an amount such that the content of resin particles (i.e., Specific Resin Particles or Comparative Resin Particles) relative to the total toner particles was the value shown in Table 3.

[0206] <Example 12> Toner 12 was obtained in the same manner as toner 1, except that the amount of specific resin particle dispersion 1 used was such that the content of specific resin particles relative to the total toner particles was as shown in Table 3, and the amount of crystalline resin particle dispersion added was adjusted so that the content of crystalline resin relative to the total binder resin was as shown in Table 3.

[0207] <Example 13> Toner 13 was obtained in the same manner as toner 1, except that the amount of crystalline resin particle dispersion added was adjusted so that the content of crystalline resin relative to the total binder resin was the value shown in Table 3.

[0208] Toner 14 was obtained in the same manner as toner 1, except that instead of specific resin particle dispersion 1, a specific resin particle dispersion of the type shown in Table 3 or a comparative resin particle dispersion was used in an amount such that the content of resin particles (i.e., specific resin particles or comparative resin particles) relative to the total toner particles was the value shown in Table 3, and the crystalline resin particle dispersion was not converted.

[0209] <Examples 15 and 28> Toners 15 and 28 were obtained in the same manner as toner 1, except that amorphous resin particle dispersions of the types shown in Table 3 were used in the amounts shown in Table 3 instead of amorphous resin particle dispersion 1.

[0210] <Example 16> Toner 16 was obtained in the same manner as toner 1, except that the rotation speed of the homogenizer was changed from 10,000 rpm to 5,000 rpm.

[0211] <Example 17> Toner 17 was obtained in the same manner as toner 1, except that the amount of crystalline resin particle dispersion added was adjusted so that the content of crystalline resin relative to the total binder resin was the value shown in Table 3.

[0212] <Example 18> Toner 18 was obtained in the same manner as toner 1, except that the amount of specific resin particle dispersion 1 used was such that the content of specific resin particles relative to the total toner particles was as shown in Table 3, and the amount of crystalline resin particle dispersion added was adjusted so that the content of crystalline resin relative to the total binder resin was as shown in Table 3.

[0213] <Example 19> Toner 19 was obtained in the same manner as toner 1, except that the pH at the time of fusion of aggregated particles was changed from 8.0 to 9.0.

[0214] <Example 20> Toner 20 was obtained in the same manner as toner 1, except that the pH at the time of fusion of aggregated particles was changed from 8.0 to 5.5.

[0215] <Example 21> Toner 21 was obtained in the same manner as toner 1, except that specific resin particle dispersion 1 was used in an amount such that the content of specific resin particles relative to the total toner particles was the value shown in Table 3, and the pH at the time of fusion of aggregated particles was changed from 8.0 to 9.5.

[0216] <Example 22> Toner 22 was obtained in the same manner as toner 1, except that the specific resin particle dispersion 1 was used in an amount such that the content of specific resin particles relative to the total toner particles was the value shown in Table 3, the amount of specific resin particles 1 was changed from 10 to 19, and the pH at the time of fusion of aggregated particles was changed from 8.0 to 6.0.

[0217] <Examples 23-27> Toners 23 to 27 were obtained in the same manner as toner 1, except that instead of specific resin particle dispersion 1, a specific resin particle dispersion of the type shown in Table 3 was used in an amount such that the content of specific resin particles relative to the total toner particles was the value shown in Table 3, and the amount of crystalline resin particle dispersion added was adjusted so that the content of crystalline resin relative to the total binder resin was the value shown in Table 3.

[0218] <Comparative Example C3> ·Amorphous resin particle dispersion 1: 169 parts ·Specified resin particle dispersion liquid 1: 33 parts ·Crystalline resin particle dispersion: 53 parts • Release agent dispersion: 25 parts • Colorant dispersion: 33 parts • Anionic surfactant (Dow Chemical, Dowfax 2A1): 4.8 parts The above raw materials, whose liquid temperature has been adjusted to 30°C, are placed in a 3L cylindrical stainless steel container, and a homogenizer (IKA Ultra-Turrax T50) is used to apply a shearing force at 4000 rpm. Then, the mixture was dispersed and mixed for 2 minutes. Next, 1.75 parts of a 10% aqueous solution of aluminum sulfate in nitric acid was gradually added dropwise as a flocculant, and the mixture was dispersed and mixed for 3 minutes at a homogenizer rotation speed of 4000 rpm to obtain the raw material dispersion.

[0219] Subsequently, the raw material dispersion was transferred to a polymerization vessel equipped with a stirring device using two paddle blades and a thermometer. The stirring speed was set to 550 rpm and heating was started with a mantle heater to promote the growth of aggregated particles at 40°C. At this time, the pH of the raw material dispersion was controlled to a range of 2.2 to 3.5 using 0.3 M nitric acid and 1 M sodium hydroxide aqueous solution. The mixture was maintained within this pH range for about 2 hours to form aggregated particles. Next, a dispersion prepared by mixing 1 part amorphous resin particle dispersion and 1 part specific resin particle dispersion was added, and the mixture was held for 60 minutes to allow the binder resin particles and specific resin particles to adhere to the surface of the aggregated particles. The temperature was then raised to 53°C, and then 21 parts amorphous resin particle dispersion was added, and the mixture was held for 60 minutes to allow the binder resin particles to adhere to the surface of the aggregated particles.

[0220] The aggregated particles were sorted while checking their size and morphology using an optical microscope and a multisizer 3. Then, the pH was adjusted to 7.8 using a 5% sodium hydroxide aqueous solution and held for 15 minutes. Subsequently, the pH was raised to 8.0 to fuse the aggregated particles, and then the temperature was increased to 85°C. After confirming the fusion of the aggregated particles using an optical microscope, heating was stopped after 2 hours, and the mixture was cooled at a rate of 1.0°C / min. The mixture was then sieved with a 20 μm mesh, washed repeatedly with water, and dried in a vacuum dryer to obtain toner particles C3.

[0221] 100 parts of the obtained toner particles and 0.7 parts of dimethyl silicone oil-treated silica particles (RY200, manufactured by Nippon Aerosil Co., Ltd.) were mixed in a Henschel mixer to obtain toner C3.

[0222] <Comparative example C4> ·Amorphous resin particle dispersion 1: 169 parts ·Specified resin particle dispersion 1: 41 parts ·Crystalline resin particle dispersion: 53 parts • Release agent dispersion: 25 parts • Colorant dispersion: 33 parts • Anionic surfactant (Dow Chemical, Dowfax 2A1): 4.8 parts The above raw materials, whose liquid temperature was adjusted to 30°C, were placed in a 3L cylindrical stainless steel container and mixed by dispersing them for 2 minutes while applying shear force at 4000 rpm using a homogenizer (IKA Ultra-Turrax T50). Next, 1.75 parts of a 10% aqueous solution of aluminum sulfate in nitric acid was gradually added dropwise as a flocculant, and the mixture was dispersed and mixed for 3 minutes at a homogenizer rotation speed of 4000 rpm to obtain the raw material dispersion.

[0223] Subsequently, the raw material dispersion was transferred to a polymerization vessel equipped with a stirring device using two paddle blades and a thermometer. The stirring speed was set to 550 rpm and heating was started with a mantle heater to promote the growth of aggregated particles at 40°C. At this time, the pH of the raw material dispersion was controlled to a range of 2.2 to 3.5 using 0.3 M nitric acid and 1 M sodium hydroxide aqueous solution. The mixture was maintained within this pH range for about 2 hours to form aggregated particles. Next, 1:42 parts of amorphous resin particle dispersion were added, and the mixture was held for 60 minutes to allow the resin particles of the binder resin to adhere to the surface of the aggregated particles.

[0224] The aggregated particles were sorted while checking their size and morphology using an optical microscope and a multi-sizer 3. The pH was then adjusted to 7.8 using a 5% sodium hydroxide solution and maintained for 15 minutes. Subsequently, the pH was raised to 8.0 to fuse the aggregated particles, and then the temperature was increased to 85°C. After confirming the fusion of the aggregated particles using an optical microscope, heating was stopped after 2 hours, and the mixture was cooled at a rate of 1.0°C / min. The mixture was then sieved with a 20 μm mesh, washed repeatedly with water, and dried in a vacuum dryer to obtain toner particles C4.

[0225] 100 parts of the obtained toner particles and 0.7 parts of dimethyl silicone oil-treated silica particles (RY200, manufactured by Nippon Aerosil Co., Ltd.) were mixed in a Henschel mixer to obtain toner C4.

[0226] <Comparative example C5> ·Amorphous resin particle dispersion 1: 169 parts ·Crystalline resin particle dispersion: 53 parts • Release agent dispersion: 25 parts • Colorant dispersion: 33 parts • Anionic surfactant (Dow Chemical, Dowfax 2A1): 4.8 parts The above raw materials, whose liquid temperature was adjusted to 30°C, were placed in a 3L cylindrical stainless steel container and mixed by dispersing them for 2 minutes while applying shear force at 4000 rpm using a homogenizer (IKA Ultra-Turrax T50). Next, 1.75 parts of a 10% aqueous solution of aluminum sulfate in nitric acid was gradually added dropwise as a flocculant, and the mixture was dispersed and mixed for 3 minutes at a homogenizer rotation speed of 4000 rpm to obtain the raw material dispersion.

[0227] Subsequently, the raw material dispersion was transferred to a polymerization vessel equipped with a stirring device using two paddle blades and a thermometer. The stirring speed was set to 550 rpm and heating was started with a mantle heater to promote the growth of aggregated particles at 40°C. At this time, the pH of the raw material dispersion was controlled to a range of 2.2 to 3.5 using 0.3 M nitric acid and 1 M sodium hydroxide aqueous solution. The mixture was maintained within this pH range for about 2 hours to form aggregated particles. Next, a dispersion was prepared by mixing 1:42 parts amorphous resin particle dispersion and 1:41 parts specific resin particle dispersion. This dispersion was divided in half and added in two separate additions. The mixture was then held for 60 minutes to allow the binder resin particles and specific resin particles to adhere to the surface of the aggregated particles.

[0228] The aggregated particles were sorted while checking their size and morphology using an optical microscope and a multisizer 3. Then, the pH was adjusted to 7.8 using a 5% sodium hydroxide aqueous solution and held for 15 minutes. Subsequently, the pH was raised to 8.0 to fuse the aggregated particles, and the temperature was increased to 85°C. After confirming the fusion of the aggregated particles using an optical microscope, heating was stopped after 2 hours, and the mixture was cooled at a rate of 1.0°C / min. The mixture was then sieved with a 20 μm mesh, washed repeatedly with water, and dried in a vacuum dryer to obtain toner particles C5.

[0229] 100 parts of the obtained toner particles and 0.7 parts of dimethyl silicone oil-treated silica particles (RY200, manufactured by Nippon Aerosil Co., Ltd.) were mixed in a Henschel mixer to obtain toner C5.

[0230] <Comparative example C6> Toner C6 was obtained in the same manner as toner 1, except that specific resin particle dispersion 1 was not added.

[0231] <Comparative Example C7> Toner C7 was obtained in the same manner as Toner 1, except that the pH at the time of fusion of aggregated particles was changed from 8.0 to 6.5, the temperature after heating was changed from 85°C to 75°C, and 5.2 parts of an anionic surfactant (Dowfax 2A1, manufactured by Dow Chemical) were added when the temperature reached 75°C.

[0232] <Comparative Example C8> Toner C8 was obtained in the same manner as toner 1, except that the pH at the time of fusion of aggregated particles was changed from 8.0 to 10.0 and the temperature after heating was changed from 85°C to 95°C.

[0233] Table 3 shows the type of specific resin particle dispersion or comparative resin particle dispersion in the obtained toner ("Particle Type" in the table), the content of specific resin particles or comparative resin particles relative to the total toner particles ("Particle Content (%)" in the table), the content of crystalline resin relative to the total binder resin ("Crystalline Resin Content (%)" in the table), and the type of amorphous resin particle dispersion ("Amorphous Resin Type" in the table). Furthermore, Table 3 shows the ratio of crystalline resin content to specific resin particle content ("Crystalline content ratio vs. particles" in the table) and the ratio of amorphous resin content to specific resin particle content ("Amorphous content ratio vs. particles" in the table) in the obtained toner. Furthermore, Table 3 shows the volume-average particle size of the toner particles in the obtained toner.

[0234] Furthermore, the storage modulus G' of the excluded component in the range of 30°C to 50°C ("30-50°C G'(Pa)" in the table), the temperature at which the specific modulus of the excluded component is reached ("Target Temperature (°C)" in the table), and the loss tangent tanδ at the temperature at which the specific modulus is reached ("Target Temperature tanδ" in the table) were determined using the method described above, and these results are shown in Tables 4 and 5. Furthermore, Tables 4 and 5 show the results obtained by the aforementioned method for the following values ​​of the obtained toner: D1(90), D50(90), D1(150), D50(150), D50(150)-D1(150) (labeled "Difference (150)" in the table), D50(90)-D1(90) (labeled "Difference (90)" in the table), the number-average molecular weight of the THF-soluble components in the toner particles (labeled "Mn" in the table), the storage modulus G' in the range of 30°C to 50°C (labeled "30-50 G'(Pa)" in the table), the temperature at which the specific modulus is reached (labeled "Target Temperature (°C)" in the table), the value of logG'(t90-150)-logG'(r90-150) (labeled "Viscoelastic Difference" in the table), and the difference (SP value (S)-SP value (R)) (labeled "SP Value Difference" in the table).

[0235] [Preparation of developer] Eight portions of the obtained toner were mixed with 100 portions of the carrier described below to obtain a developer.

[0236] -Creating a Career- • Ferrite particles (average particle size 50 μm) 100 units • Toluene 14 parts • Styrene / methyl methacrylate copolymer (copolymerization ratio 15 / 85) 3 parts • Carbon black 0.2 parts The above components, excluding ferrite particles, were dispersed in a sand mill to prepare a dispersion. This dispersion was then placed together with ferrite particles in a vacuum-degassed kneader and dried under reduced pressure while stirring to obtain a carrier.

[0237] [evaluation] <Glossiness difference> The developer obtained was used to fill the developer unit of the ApeosPortIV C3370 color copier (manufactured by Fujifilm Business Innovation Co., Ltd.) from which the fuser unit had been removed, resulting in a toner load of 0.45 mg / cm². 2 The unfixed image was output after adjustments were made to achieve the desired result. Fujifilm Business Innovation Co., Ltd.'s OS Coat W paper, A4 size (basis weight 127 gsm), was used as the recording medium. The output image is 50 mm x 50 mm in size with 100% image density.

[0238] For the fixation evaluation, a modified ApeosPortIV C3370 manufactured by Fujifilm Business Innovation Co., Ltd. was used, with the fuser removed and the nip pressure and fixation temperature modified to allow for adjustment. The process speed was 175 mm / sec. Under these conditions, the unfixed image was processed under low temperature and low pressure conditions (specifically, fuser temperature 120 degrees Celsius, nip pressure 1.6 kgf / cm²). 2 ) and under high temperature and high pressure conditions (specifically, fuser temperature 180 degrees Celsius, nip pressure 6.0 kgf / cm²) 2 The images were fixed under two conditions, and a fixed image was obtained. The glossiness of the fixed image portion was measured using a BYK Microtrigloss gloss meter at 60° gloss, and the difference in glossiness (i.e., difference in glossiness conditions) between the fixed image under low temperature and low pressure conditions and the fixed image under high temperature and high pressure conditions was determined. The results are shown in Tables 4-5. Furthermore, if the gloss difference is less than 5, it is difficult to visually perceive the difference in gloss; if the gloss difference is between 5 and 10, the difference in gloss is visible but minor; if the gloss difference is between 10 and 15, the difference in gloss is visible but within an acceptable range; and if the gloss difference is 15 or more, the difference in gloss is large and outside an acceptable range.

[0239] <Persistency> For evaluating the difference in glossiness, fixed images under low temperature and low pressure conditions were bent using weights, and image quality was evaluated based on the degree of image loss in that area. The evaluation criteria are as follows, and the results are shown in Tables 4-5. G1: No image defects were observed. G2: Image defects were observed, but they were minor. G3: Slight image defects were observed, but within acceptable limits. G4: Image loss was observed.

[0240] [Table 3]

[0241] [Table 4]

[0242] [Table 5]

[0243] From the above results, it can be seen that the toner of this embodiment achieves good fixation while showing a small difference in gloss between the image fixed under low temperature and low pressure conditions and the image fixed under high temperature and high pressure conditions.

[0244] This embodiment includes the following aspects. (((1))) A toner for developing electrostatic images, comprising toner particles containing a binder resin, In the dynamic viscoelasticity measurement of the electrostatic image developing toner, when the loss tangent tanδ at a temperature of 90°C and a strain of 1% is D1(90), the loss tangent tanδ at a temperature of 90°C and a strain of 50% is D50(90), the loss tangent tanδ at a temperature of 150°C and a strain of 1% is D1(150), and the loss tangent tanδ at a temperature of 150°C and a strain of 50% is D50(150), D1(90), D50(90), D1(150), and D50(150) are each between 0.5 and 2.5. The value of D50(150)-D1(150) is less than 1.5. The value of D50(90)-D1(90) is less than 1.0. The toner particles further contain resin particles, A toner for developing electrostatic images, wherein the number-average molecular weight of the tetrahydrofuran-soluble components in the toner particles is 5,000 or more and 15,000 or less.

[0245] (((2))) The electrostatic image developing toner according to (((1))), wherein the glass transition temperature Tg determined from the dynamic viscoelasticity measurement of the resin particles is 10°C or more and 45°C or less. (((3))) The electrostatic image developing toner according to (((1))) or (((2))), wherein, in the dynamic viscoelasticity measurement of the resin particles when the temperature is increased by 2°C / min, the loss tangent tanδ in the range of 30°C to 150°C is 0.01 to 2.5. (((4))) The toner for developing electrostatic images according to any one of (((1))) to (((3))), wherein the number-average particle size of the resin particles is 60 nm or more and 300 nm or less. (((5))) The toner for developing electrostatic images according to any one of (((1))) to (((4))), wherein the content of the resin particles is 2% by mass or more and 30% by mass or less of the total toner particles.

[0246] (((6))) The aforementioned resin particles are cross-linked resin particles, an electrostatic image developing toner as described in any one of (((1))) to (((5))). (((7))) The toner for developing electrostatic images according to (((6))), wherein the crosslinked resin particles are styrene (meth)acrylic resin particles. (((8))) The difference between the solubility parameter SP value (S) of the resin particles and the solubility parameter SP value (R) of the binder resin (SP value (S) - SP value (R)) is -0.32 or more and -0.12 or less, as described in any one of (((1))) to (((7))) for developing electrostatic images.

[0247] (((9))) In a dynamic viscoelasticity measurement of the component obtained by removing the resin particles from the toner particles during a temperature increase of 2°C / min, the storage modulus G' in the range of 30°C to 50°C is 1 × 10⁻⁶. 8 The Pa value is greater than or equal to the storage modulus G' of 1 × 10⁻⁶. 5A toner for developing electrostatic images, as described in any one of (((1))) to (((8))), wherein the temperature at which it reaches below Pa is 65°C or higher and 90°C or lower. (((10))) In a dynamic viscoelasticity measurement of the component obtained by removing the resin particles from the toner particles during a temperature increase of 2°C / min, the storage modulus G' was 1 × 10⁻⁶. 5 The toner for developing electrostatic images as described in (((9))), wherein the loss tangent tanδ at temperatures below Pa is 0.8 or more and 1.6 or less.

[0248] (((11))) In dynamic viscoelasticity measurements during a 2°C / min temperature increase, when the storage modulus of the resin particles is G'(p90-150), the storage modulus of the toner particles is G'(t90-150), and the storage modulus of the component obtained by removing the resin particles from the toner particles is G'(r90-150), then 1 × 10⁻¹⁰ 4 Pa≦G'(p90-150)≦1×10 6 A toner for developing electrostatic images, as described in any one of (((1))) to (((10))), where Pa and 1.0 ≤ logG'(t90-150) - logG'(r90-150) ≤ 4.0. (((12))) In the dynamic viscoelasticity measurement of the electrostatic image developing toner during a temperature increase of 2°C / min, the storage modulus G' in the range of 30°C to 50°C was 1 × 10⁻¹⁰. 8 The Pa value is greater than or equal to the storage modulus G' of 1 × 10⁻⁶. 5 A toner for developing electrostatic images, as described in any one of (((1))) to (((11))), wherein the temperature at which it reaches below Pa is 65°C or higher and 90°C or lower.

[0249] (((13))) The aforementioned binder resin contains a crystalline resin, The toner for developing electrostatic images according to any one of (((1))) to (((12))), wherein the content of the crystalline resin is 4% by mass or more and 50% by mass or less with respect to the total amount of the binder resin. (((14))) The aforementioned binder resin contains a polyester resin, and is a toner for developing electrostatic images according to any one of (((1))) to (((13))). (((15))) The toner for developing electrostatic images according to (((14))), wherein the binder resin comprises an amorphous polyester resin having aliphatic dicarboxylic acid units and a crystalline polyester resin having aliphatic dicarboxylic acid units. (((16))) The resin particles have a bifunctional alkyl acrylate as a constituent unit, and the number of carbon atoms in the alkylene chain of the bifunctional alkyl acrylate is 6 or more, as described in any one of (((1))) to (((15))).

[0250] (((17))) A electrostatic image developer containing the toner for electrostatic image development described in any one of (((1))) to (((16))). (((18))) It contains the electrostatic image developing toner described in any one of (((1))) to (((16))), A toner cartridge that is attached to and detached from an image forming machine. (((19))) The developing means contains the electrostatic image developer described in (((17))) and develops the electrostatic image formed on the surface of the image holder as a toner image using the electrostatic image developer, A process cartridge that is attached to and detached from an image forming apparatus. (((20))) Image holder and, A charging means for charging the surface of the image holder, A means for forming an electrostatic image on the surface of the charged image holder, A developing means containing the electrostatic image developer described in (((17))) and developing the electrostatic image formed on the surface of the image holder as a toner image using the electrostatic image developer, A transfer means for transferring a toner image formed on the surface of the image holder to the surface of a recording medium, Fixing means for fixing the toner image transferred to the surface of the recording medium, An image forming apparatus equipped with the following features. (((twenty one))) A charging step in which the surface of the image holder is charged, A step of forming an electrostatic image on the surface of the charged image holder, A developing step in which the electrostatic image formed on the surface of the image holder is developed as a toner image using the electrostatic image developer described in (((17))), A transfer step of transferring the toner image formed on the surface of the image holder to the surface of the recording medium, A fixing step for fixing the toner image transferred to the surface of the recording medium, An image forming method having the following characteristics.

[0251] According to the invention of (((1))), when any of D1(90), D50(90), D1(150), and D50(150) is less than 0.5 or greater than 2.5, when the value of D50(150)-D1(150) is 1.5 or greater, or when the value of D50(90)-D1(90) is 1.0 or greater, when the toner particles do not contain resin particles, or when the number average molecular weight of the tetrahydrofuran soluble components in the toner particles is less than 5000 or greater than 15000, a toner for electrostatic image development is provided that provides good fixability while having a small difference in gloss between the fixed image under low temperature and low pressure conditions and the fixed image under high temperature and high pressure conditions.

[0252] According to the invention of (((2))), compared to cases where the glass transition temperature Tg determined from the dynamic viscoelasticity measurement of resin particles is less than 10°C or more than 45°C, a toner for developing electrostatic images is provided that provides good fixability while having a small difference in gloss between the image fixed under low temperature and low pressure conditions and the image fixed under high temperature and high pressure conditions. According to the invention of (((3))), a toner for developing electrostatic images is provided in which the difference in gloss between an image fixed under low temperature and low pressure conditions and an image fixed under high temperature and high pressure conditions is small, compared to the case where the loss tangent tanδ of resin particles at 150°C exceeds 2.5. According to the invention of (((4))), a toner for developing electrostatic images is provided in which the difference in gloss between an image fixed under low temperature and low pressure conditions and an image fixed under high temperature and high pressure conditions is smaller compared to the case where the number average particle size of the resin particles exceeds 300 nm. According to the invention of (((5))), a toner for developing electrostatic images is provided in which the difference in gloss between an image fixed under low temperature and low pressure conditions and an image fixed under high temperature and high pressure conditions is smaller compared to the case in which the resin particle content is less than 2% by mass. According to the invention of (((6))), a toner for developing electrostatic images is provided in which the difference in gloss between the image fixed under low temperature and low pressure conditions and the image fixed under high temperature and high pressure conditions is smaller compared to the case in which the resin particles are non-crosslinked resin particles. According to the invention of (((7))), a toner for developing electrostatic images is provided in which the difference in gloss between the image fixed under low temperature and low pressure conditions and the image fixed under high temperature and high pressure conditions is smaller compared to the case in which the resin particles are polyester resin particles.

[0253] According to the invention of (((8))), a toner for developing electrostatic images is provided in which the difference in gloss between an image fixed under low temperature and low pressure conditions and an image fixed under high temperature and high pressure conditions is smaller compared to the case where the difference (SP value (S) - SP value (R)) is less than -0.32. According to the invention of (((9))), the storage modulus G' of the component obtained by removing resin particles from toner particles is 1 × 10 5 Compared to cases where the temperature at which Pa is reached exceeds 90°C, a toner for developing electrostatic images with better fixing properties is provided. According to the invention of (((10))), the storage modulus G' of the component obtained by removing resin particles from toner particles is 1 × 10 5 A toner for developing electrostatic images is provided that exhibits a smaller difference in gloss between images fixed under low-temperature, low-pressure conditions and images fixed under high-temperature, high-pressure conditions, compared to cases where the loss tangent tanδ at temperatures below Pa exceeds 1.6.

[0254] According to the invention of (((11))), G'(p90-150) is 1 × 10 4 Less than Pa or 1 x 10 6A toner for developing electrostatic images is provided that exhibits a smaller difference in gloss between images fixed under low temperature and low pressure conditions and images fixed under high temperature and high pressure conditions, compared to cases where the Pa value exceeds Pa, or where logG'(t90-150)-logG'(r90-150) is less than 1.0 or greater than 4.0. According to the invention of (((12))), the storage modulus G' of the toner for electrostatic image development is 1 × 10 5 Compared to cases where the temperature at which Pa is reached exceeds 90°C, a toner for developing electrostatic images with better fixing properties is provided. According to the invention of (((13))), a toner for developing electrostatic images is provided in which the difference in gloss between an image fixed under low temperature and low pressure conditions and an image fixed under high temperature and high pressure conditions is smaller compared to the case in which the crystalline resin content exceeds 50% by mass. According to the invention of (((14))), a toner for developing electrostatic images with better fixing properties is provided compared to the case where the binder resin is made of styrene acrylic resin. According to the invention of (((15))), a toner for developing electrostatic images is provided in which the difference in gloss between the image fixed under low temperature and low pressure conditions and the image fixed under high temperature and high pressure conditions is smaller compared to the case in which the binder resin does not contain an amorphous polyester resin having aliphatic dicarboxylic acid units or a crystalline polyester resin having aliphatic dicarboxylic acid units. According to the invention of (((16))), a toner for developing electrostatic images is provided that has a smaller difference in gloss between an image fixed under low temperature and low pressure conditions and an image fixed under high temperature and high pressure conditions compared to a case in which a difunctional alkyl acrylate is not used as a constituent unit, or a case in which a difunctional alkyl acrylate is used as a constituent unit and the number of carbon atoms in the alkylene chain of the difunctional alkyl acrylate is 5 or less.

[0255] According to the inventions of (((17))), (((18))), (((19))), (((20))), or (((21))), when a toner for electrostatic image development is applied in which any of D1(90), D50(90), D1(150), and D50(150) is less than 0.5 or greater than 2.5, the value of D50(150)-D1(150) is 1.5 or more, or the value of D50(90)-D1(90) is 1.0 or more, the toner particles become resin particles Compared to using an electrostatic image developing toner that does not contain, or using an electrostatic image developing toner in which the number average molecular weight of tetrahydrofuran-soluble components in the toner particles is less than 5,000 or more than 15,000, the present invention provides an electrostatic image developing agent, toner cartridge, process cartridge, image forming apparatus, or image forming method that achieves good fixing performance while minimizing the difference in gloss between images fixed under low temperature and low pressure conditions and images fixed under high temperature and high pressure conditions. [Explanation of Symbols]

[0256] 1Y, 1M, 1C, 1K photoreceptors (examples of image retainers) 2Y, 2M, 2C, 2K Charging Rolls (Example of Charging Method) 3. Exposure apparatus (an example of electrostatic image formation means) 3Y, 3M, 3C, 3K laser beam 4Y, 4M, 4C, 4K developing apparatus (an example of a developing method) 5Y, 5M, 5C, 5K Primary Transfer Rolls (Example of Primary Transfer Method) 6Y, 6M, 6C, 6K Photoreceptor Cleaning Device (Example of Cleaning Method) 8Y, 8M, 8C, 8K Toner Cartridges 10Y, 10M, 10C, 10K Image Forming Units 20. Intermediate transfer belt (an example of an intermediate transfer material) 22 Drive Roll 24 Support Rolls 26. Secondary transfer roll (an example of a secondary transfer means) 28 Fixing device (an example of a fixing means) 30 Intermediate Transfer Body Cleaning Apparatus 107 Photoreceptor (an example of an image-retaining element) 108 Charging Roll (Example of Charging Method) 109 Exposure apparatus (an example of a means for forming electrostatic images) 111 Developing apparatus (an example of a developing means) 112 Transfer device (an example of a transfer means) 113 Photoreceptor cleaning device (an example of a cleaning method) 115 Fixing device (an example of a fixing means) 116 Mounting Rail 117 cabinets 118 Aperture for exposure 200 Process Cartridges 300 Recording paper (an example of a recording medium) P Recording paper (an example of a recording medium)

Claims

1. A toner for developing electrostatic images, comprising toner particles containing polyester resin as a binder resin, In the dynamic viscoelasticity measurement of the electrostatic image developing toner, when the loss tangent tanδ at a temperature of 90°C and a strain of 1% is D1(90), the loss tangent tanδ at a temperature of 90°C and a strain of 50% is D50(90), the loss tangent tanδ at a temperature of 150°C and a strain of 1% is D1(150), and the loss tangent tanδ at a temperature of 150°C and a strain of 50% is D50(150), D1(90), D50(90), D1(150), and D50(150) are each between 0.5 and 2.

5. The value of D50(150) - D1(150) is less than 1.

5. The value of D50(90) - D1(90) is less than 1.

0. The toner particles further contain crosslinked resin particles, which are styrene (meth)acrylic resin particles, and these resin particles are contained in both the surface region and the central region of the toner particles. A toner for developing electrostatic images, wherein the number-average molecular weight of the tetrahydrofuran-soluble components in the toner particles is 5,000 or more and 15,000 or less.

2. The electrostatic image developing toner according to claim 1, wherein the glass transition temperature Tg determined from the dynamic viscoelasticity measurement of the resin particles is 10°C or more and 45°C or less.

3. The electrostatic image developing toner according to claim 1, wherein in the dynamic viscoelasticity measurement of the resin particles when the temperature is increased by 2°C / min, the loss tangent tanδ in the range of 30°C to 150°C is 0.01 to 2.

5.

4. The toner for developing electrostatic images according to claim 1, wherein the number-average particle size of the resin particles is 60 nm or more and 300 nm or less.

5. The toner for developing electrostatic images according to claim 1, wherein the content of the resin particles is 2% by mass or more and 30% by mass or less with respect to the total amount of toner particles.

6. The toner for developing electrostatic images according to claim 1, wherein the difference between the solubility parameter SP value (S) of the resin particles and the solubility parameter SP value (R) of the binder resin (SP value (S) - SP value (R)) is -0.32 or more and -0.12 or less.

7. In a dynamic viscoelasticity measurement of the component obtained by removing the resin particles from the toner particles during a temperature increase of 2°C / min, the storage modulus G' in the range of 30°C to 50°C is 1 × 10⁻⁶. ８ The pressure is greater than or equal to Pa, and the storage modulus G' is 1 × 10⁻⁶. ５ The electrostatic image developing toner according to claim 1, wherein the temperature at which the pressure drops below Pa is 65°C or higher and 90°C or lower.

8. In a dynamic viscoelasticity measurement of the component obtained by removing the resin particles from the toner particles during a temperature increase of 2°C / min, the storage modulus G' was 1 × 10⁻⁶. ５ The toner for developing electrostatic images according to claim 7, wherein the loss tangent tanδ at temperatures below Pa is 0.8 or more and 1.6 or less.

9. In dynamic viscoelasticity measurements during a 2°C / min temperature increase, when the storage modulus of the resin particles is G'(p90-150), the storage modulus of the toner particles is G'(t90-150), and the storage modulus of the component obtained by removing the resin particles from the toner particles is G'(r90-150), 1 x 10 ４ Pa≦G'(p90-150)≦1×10 ６ Pa, and, The electrostatic image developing toner according to claim 1, wherein 1.0 ≤ logG'(t90-150) - logG'(r90-150) ≤ 4.

0.

10. In the dynamic viscoelasticity measurement of the electrostatic image developing toner during a temperature increase of 2°C / min, the storage modulus G' in the range of 30°C to 50°C was 1 × 10⁻¹⁰. ８ The pressure is greater than or equal to Pa, and the storage modulus G' is 1 × 10⁻⁶. ５ The electrostatic image developing toner according to claim 1, wherein the temperature at which the pressure drops below Pa is 65°C or higher and 90°C or lower.

11. The aforementioned binder resin contains a crystalline resin, The toner for developing electrostatic images according to claim 1, wherein the content of the crystalline resin is 4% by mass or more and 50% by mass or less with respect to the total amount of the binder resin.

12. The toner for developing electrostatic images according to claim 1, wherein the binder resin contains an amorphous polyester resin having aliphatic dicarboxylic acid units and a crystalline polyester resin having aliphatic dicarboxylic acid units.

13. The toner for developing electrostatic images according to claim 1, wherein the resin particles have a difunctional alkyl acrylate as a constituent unit, and the number of carbon atoms in the alkylene chain of the difunctional alkyl acrylate is 6 or more.

14. The glass transition temperature Tg, determined from the dynamic viscoelasticity measurement of the resin particles, is between 10°C and 45°C. In the dynamic viscoelasticity measurement of the resin particles during a temperature increase of 2°C / min, the loss tangent tanδ in the range of 30°C to 150°C is 0.01 to 2.

5. In the measurement of the dynamic viscoelasticity of the toner for electrostatic charge image development during temperature increase at 2°C / min, the storage elastic modulus G' in the range of 30°C or higher and 50°C or lower is 1×10 ８ Pa or higher, and the temperature at which the storage elastic modulus G' reaches less than 1×10 ５ Pa is 65°C or higher and 90°C or lower. The toner for electrostatic charge image development according to claim 1.

15. The glass transition temperature Tg, determined from the dynamic viscoelasticity measurement of the resin particles, is between 10°C and 45°C. In the dynamic viscoelasticity measurement of the resin particles during a temperature increase of 2°C / min, the loss tangent tanδ in the range of 30°C to 150°C is 0.01 to 2.

5. The toner for developing electrostatic images according to claim 1, wherein the resin particles have a difunctional alkyl acrylate as a constituent unit, and the number of carbon atoms in the alkylene chain of the difunctional alkyl acrylate is 6 or more.

16. A electrostatic image developer comprising the electrostatic image developing toner according to any one of claims 1 to 15.

17. A toner for electrostatic image development according to any one of claims 1 to 15 is contained, A toner cartridge that is attached to and detached from an image forming machine.

18. The development means comprises a static charge image developer according to claim 16, and develops a static charge image formed on the surface of an image holder as a toner image using the static charge image developer, A process cartridge that is attached to and detached from an image forming apparatus.

19. Image holder and, A charging means for charging the surface of the image holder, A means for forming an electrostatic image on the surface of the charged image holder, A developing means comprising: containing the electrostatic image developer described in claim 16; and developing the electrostatic image formed on the surface of the image holder as a toner image using the electrostatic image developer; A transfer means for transferring a toner image formed on the surface of the image holder to the surface of a recording medium, Fixing means for fixing the toner image transferred to the surface of the recording medium, An image forming apparatus equipped with the following features.

20. A charging step in which the surface of the image holder is charged, A step of forming an electrostatic image on the surface of the charged image holder, A developing step of developing the electrostatic image formed on the surface of the image holder as a toner image using the electrostatic image developer described in claim 16, A transfer step of transferring the toner image formed on the surface of the image holder to the surface of the recording medium, A fixing step for fixing the toner image transferred to the surface of the recording medium, An image forming method having the following characteristics.

Images