Electrostatic charge image developing toner, electrostatic charge image developer, toner cartridge, process cartridge, and image forming apparatus and method

Abstract

An electrostatic image developing toner, an electrostatic image developer, a toner cartridge, a process cartridge, and an image forming apparatus and method. The toner includes toner particles including an amorphous polyester resin and a crystalline resin, the toner particles including, as the amorphous polyester resin, an amorphous polyester resin (S) having at least one of a structural unit derived from an aliphatic dicarboxylic acid represented by formula (A) and a structural unit derived from an aliphatic diol represented by formula (B), the ratio of the total of the two types of structural units in the total of all structural units constituting the amorphous polyester resin is 0.5% to 10.0% in terms of molar ratio, and the toner particles have a minimum value tan [delta] (min) of loss tangent of 0.50 to 1.00 at 50 to 80 DEG C in a dynamic viscoelasticity measurement when the temperature is raised from 30 DEG C to 120 DEG C in the toner particles. And nA and nB each independently represent an integer of 2-12 (inclusive).

Description

Technical Field

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

[0002] Patent Document 1 discloses a toner for electrostatic image development, comprising toner particles containing a binder resin, wherein, in a dynamic viscoelasticity measurement of the toner for electrostatic image development, a loss tangent tanδ at a temperature of 90°C and a strain of 1% is set as D1(90), a loss tangent tanδ at a temperature of 90°C and a strain of 50% is set as D50(90), a loss tangent tanδ at a temperature of 150°C and a strain of 1% is set as D1(150), and a loss tangent tanδ at a temperature of 150°C and a strain of 1% is set as D2(150). When the loss tangent tanδ at 50% of the toner volume is set to D50(150), D1(90), D50(90), D1(150) and D50(150) are respectively 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, and the number average molecular weight of the tetrahydrofuran-soluble component in the toner particles is 5000 or more and 15000 or less.

[0003] Patent Document 2 discloses "a toner for electrostatic image development, comprising at least a binder resin, a colorant, and a wax, wherein the binder resin component comprises, as main components, a non-crystalline polyester resin and a crystalline polyester resin, and the crystalline polyester resin is contained in an amount of 1 part by mass or more and 15 parts by mass or less per 100 parts by mass of the binder resin, and the melting point A and the temperature B at which the storage modulus G' of the crystalline polyester resin becomes 20,000 Pa satisfy the following formula (1): BA<20, and the loss tangent at 80°C or above is 1 or less."

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 2023-48127

[0005] Patent Document 2: Japanese Patent Application Laid-Open No. 2012-93704 Summary of the Invention

[0006] An object of the present invention is to provide a toner for developing electrostatic images, wherein, compared to toner particles comprising an amorphous polyester resin as a binder resin and a crystalline resin, the toner particles comprise an amorphous polyester resin (S) as the amorphous polyester resin, the amorphous polyester resin (S) comprising at least one of a structural unit derived from an aliphatic dicarboxylic acid represented by the structural formula (A) and a structural unit derived from an aliphatic diol represented by the structural formula (B), the toner has low-temperature fixing properties and can suppress edge contamination of a recording medium when the total molar ratio of the structural unit derived from the aliphatic dicarboxylic acid represented by the structural formula (A) and the structural unit derived from the aliphatic diol represented by the structural formula (B) in all structural units constituting the amorphous polyester resin is less than 0.5% or exceeds 10.0%, or when the minimum value of the loss tangent, tan δ (min), existing at 50°C or higher and 80°C or lower in a dynamic viscoelasticity measurement at a temperature of 30°C to 120°C in the toner particles is less than 0.5 or exceeds 1.0.

[0007] Means for solving the above-mentioned problems include the following.

[0008] <1>

[0009] A toner for developing electrostatic images, comprising toner particles containing an amorphous polyester resin as a binder resin and a crystalline resin,

[0010] The toner particles contain an amorphous polyester resin (S) as the amorphous polyester resin, wherein the amorphous polyester resin (S) has at least one of a structural unit derived from an aliphatic dicarboxylic acid represented by the following structural formula (A) and a structural unit derived from an aliphatic diol represented by the following structural formula (B).

[0011] The total proportion of the structural unit derived from an aliphatic dicarboxylic acid represented by the following structural formula (A) and the structural unit derived from an aliphatic diol represented by the following structural formula (B) in all the structural units constituting the amorphous polyester resin is 0.5% or more and 10.0% or less by mole,

[0012] In a dynamic viscoelasticity measurement of the toner particles when the temperature is increased from 30° C. to 120° C., a minimum loss tangent tan δ (min) exists at 50° C. to 80° C., and the minimum loss tangent tan δ (min) is 0.50 to 1.00.

[0013] [Chemical Formula 1]

[0014]

[0015] In structural formulae (A) and (B), nA and nB each independently represent an integer of 2 or more and 12 or less.

[0016] <2>

[0017] The electrostatic image developing toner according to <1>, wherein

[0018] The amorphous polyester resin (S) comprises only the structural unit derived from an aliphatic dicarboxylic acid represented by the structural formula (A) and the structural unit derived from an aliphatic diol represented by the structural formula (B).

[0019] The proportion of the structural unit derived from an aliphatic dicarboxylic acid represented by the structural formula (A) in all the structural units derived from carboxylic acid constituting the amorphous polyester resin is 2.0% or more and 15.0% or less in terms of molar ratio.

[0020] <3>

[0021] The electrostatic image developing toner according to <2>, wherein

[0022] The proportion of the structural unit derived from an aliphatic dicarboxylic acid represented by the structural formula (A) in all the structural units derived from carboxylic acid constituting the amorphous polyester resin is 3.0% or more and 10.0% or less by mole.

[0023] <4>

[0024] The electrostatic image developing toner according to any one of <1> to <3>, wherein

[0025] The minimum value of the loss tangent, tan δ (min), is 0.60 or more and 0.90 or less.

[0026] <5>

[0027] The electrostatic image developing toner according to any one of <1> to <4>, wherein

[0028] The ratio of the minimum value of the loss tangent tanδ(min) to the loss tangent tanδ(90) at a temperature of 90°C, tanδ(90) / tanδ(min), is 2.5 or less.

[0029] <6>

[0030] The electrostatic image developing toner according to any one of <1> to <5>, wherein

[0031] The toner particles include internally added crosslinked resin particles.

[0032] <7>

[0033] The electrostatic image developing toner according to <6>, wherein

[0034] The glass transition temperature Tg of the internally added cross-linked resin particles is 0° C. or higher and 40° C. or lower.

[0035] <8>

[0036] The electrostatic image developing toner according to any one of <1> to <7>, wherein

[0037] The crystalline resin is a crystalline polyester resin,

[0038] The content of the crystalline polyester resin relative to the binder resin is 10% by mass or more and 30% by mass or less.

[0039] <9>

[0040] The electrostatic image developing toner according to any one of <1> to <8>, wherein

[0041] The toner particles contain one or more metal ions selected from the group consisting of Al, Mg, and Ca.

[0042] The ratio of the amount of the metal ion M1 to the acid value AV1 of the binder resin is 1.0×10 3 Above and 4.0×10 3 the following.

[0043] <10>

[0044] The electrostatic image developing toner according to <9>, wherein

[0045] The ratio of the amount of the metal ion M1 to the acid value AV1 of the binder resin is 2.0×10 3 Above and 3.5×10 3 the following.

[0046] <11>

[0047] An electrostatic image developer comprising the electrostatic image developing toner according to any one of <1> to <10>.

[0048] <12>

[0049] A toner cartridge containing the electrostatic image developing toner described in any one of <1> to <10>,

[0050] The image forming apparatus is mounted and removed from the image forming apparatus.

[0051] <13>

[0052] A process cartridge comprising a developing device that contains the electrostatic image developer described in <11> and develops an electrostatic image formed on a surface of an image holding member into a toner image using the electrostatic image developer.

[0053] The process cartridge is attachable to and detachable from the image forming apparatus.

[0054] <14>

[0055] An image forming apparatus comprising:

[0056] Image holding body;

[0057] a charging device for charging the surface of the image holding member;

[0058] an electrostatic image forming device for forming an electrostatic image on the charged surface of the image holding member;

[0059] a developing device that accommodates the electrostatic image developer described in <11> and develops the electrostatic image formed on the surface of the image holding member into a toner image using the electrostatic image developer;

[0060] a transfer device that transfers the toner image formed on the surface of the image holding member to the surface of a recording medium; and

[0061] The fixing device fixes the toner image transferred onto the surface of the recording medium.

[0062] <15>

[0063] An image forming method comprising:

[0064] a charging process for charging the surface of the image holding member;

[0065] an electrostatic image forming step of forming an electrostatic image on the charged surface of the image holding member;

[0066] a developing step of developing the electrostatic image formed on the surface of the image holding member into a toner image using the electrostatic image developer described in <11>;

[0067] a transfer step of transferring the toner image formed on the surface of the image holding member to the surface of a recording medium; and

[0068] The fixing step fixes the toner image transferred onto the surface of the recording medium.

[0069] Effects of the Invention

[0070] According to the invention according to <1>, there is provided a toner for developing an electrostatic image: compared to a toner having toner particles containing an amorphous polyester resin as a binder resin and a crystalline resin, the toner particles contain an amorphous polyester resin (S) as the amorphous polyester resin, the amorphous polyester resin (S) having at least one of a structural unit derived from an aliphatic dicarboxylic acid represented by structural formula (A) and a structural unit derived from an aliphatic diol represented by structural formula (B), When the total molar ratio of the structural units of the carboxylic acid and the structural units derived from the aliphatic diol represented by the structural formula (B) in all the structural units constituting the amorphous polyester resin is less than 0.5% or exceeds 10.0%, or when the minimum value of the loss tangent tanδ(min) existing at 50°C to 80°C in the dynamic viscoelasticity measurement at a temperature rise from 30°C to 120°C in the toner particles is less than 0.50 or exceeds 1.00, the toner has low-temperature fixing ability and can suppress contamination of the edge of the recording medium.

[0071] According to the invention <2>, there is provided a toner for developing electrostatic images having low-temperature fixing properties and capable of suppressing edge contamination of a recording medium, compared to a case where the molar ratio of the structural unit derived from an aliphatic dicarboxylic acid represented by structural formula (A) in all the structural units derived from carboxylic acid constituting the amorphous polyester resin is less than 2.0% or exceeds 15.0%.

[0072] According to the invention according to <3>, there is provided a toner for developing electrostatic images, which has low-temperature fixing properties and can suppress contamination of the edge of a recording medium, compared to a case where the proportion of the structural unit derived from an aliphatic dicarboxylic acid represented by structural formula (A) in all the structural units derived from carboxylic acid constituting the amorphous polyester resin is less than 3.0% or exceeds 10.0% by mole.

[0073] According to the invention according to <4>, there is provided a toner for electrostatic image development, wherein, in a measurement of dynamic viscoelasticity of toner particles when the temperature is increased from 30°C to 120°C, a minimum value of loss tangent tanδ(min) is present at a temperature of 50°C to 80°C, and the minimum value of loss tangent tanδ(min) is less than 0.60 or exceeds 0.90, the toner has low-temperature fixing properties, and can suppress contamination of the edge of a recording medium.

[0074] According to the invention described in <5>, there is provided a toner for electrostatic image development having low-temperature fixability and capable of suppressing contamination of the edge of a recording medium, as compared to a case where the ratio of the loss tangent tanδ(90) / tanδ(min) (the ratio of the loss tangent tanδ(90) to the loss tangent tanδ(90) at a temperature of 90°C exceeds 2.5.

[0075] According to the invention according to <6>, there is provided a toner for developing electrostatic images that has low-temperature fixing properties compared to a case where toner particles do not contain internally added crosslinked resin particles and can suppress contamination of the edge of a recording medium.

[0076] According to the invention <7>, there is provided a toner for developing electrostatic images having low-temperature fixability compared to a case where the glass transition temperature Tg of the internally added crosslinked resin particles is less than 0°C or exceeds 40°C and capable of suppressing edge contamination of a recording medium.

[0077] According to the invention <8>, there is provided a toner for developing electrostatic images having low-temperature fixability and capable of suppressing edge contamination of a recording medium compared to a case where the content of the crystalline polyester resin relative to the binder resin is less than 10% by mass or exceeds 30% by mass.

[0078] According to the invention according to <9>, there is provided a toner for developing an electrostatic image, wherein the ratio AV1 / M1 of the amount of metal ions M1 to the acid value AV1 of the binder resin is less than 1.0×10 3 or more than 4.0×10 3 In the case of the above, it has low-temperature fixing properties and can suppress contamination of the end portions of the recording medium.

[0079] According to the invention according to <10>, there is provided a toner for developing an electrostatic image, wherein the ratio AV1 / M1 of the amount of metal ions M1 to the acid value AV1 of the binder resin is less than 2.0×10 3 or more than 3.5×10 3 In the case of the above, it has low-temperature fixing properties and can suppress contamination of the end portions of the recording medium.

[0080] According to the invention according to <11>, <12>, <13>, <14> or <15>, there is provided an electrostatic image developing agent, a toner cartridge, a process cartridge, an image forming apparatus or an image forming method: compared to toner particles containing an amorphous polyester resin as a binder resin and a crystalline resin, the toner particles contain an amorphous polyester resin (S) as the amorphous polyester resin, the amorphous polyester resin (S) having at least one of a structural unit derived from an aliphatic dicarboxylic acid represented by structural formula (A) and a structural unit derived from an aliphatic diol represented by structural formula (B); In the toner, when the total molar ratio of the structural units derived from aliphatic dicarboxylic acid represented by structural formula (A) and the structural units derived from aliphatic diol represented by structural formula (B) in all the structural units constituting the amorphous polyester resin is less than 0.5% or exceeds 10.0%, or when the minimum value of the loss tangent tanδ (min) existing at 50°C to 80°C in the dynamic viscoelasticity measurement at a temperature of 30°C to 120°C in the toner particles is less than 0.50 or exceeds 1.00, the toner has low-temperature fixing properties and can suppress contamination of the edge of the recording medium. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] Embodiments of the present invention will be described in detail with reference to the following drawings.

[0082] Figure 1 FIG. 1 is a schematic structural diagram showing an example of an image forming apparatus according to the present embodiment;

[0083] Figure 2 This is a schematic structural diagram showing an example of a process cartridge that is attached to and detached from the image forming apparatus according to the present embodiment.

[0084] Explanation of symbols

[0085] 1Y, 1M, 1C, 1K - photoreceptor (an example of an image holding member), 2Y, 2M, 2C, 2K - charging roller (an example of a charging device), 3 - exposure device (an example of an electrostatic image forming device), 3Y, 3M, 3C, 3K - laser beam, 4Y, 4M, 4C, 4K - developing device (an example of a developing device), 5Y, 5M, 5C, 5K - primary transfer roller (an example of a primary transfer device), 6Y, 6M, 6C, 6K - photoreceptor cleaning device (an example of a cleaning device), 8Y, 8M, 8C, 8K - toner cartridge, 10Y, 10M, 10C, 10K - image forming unit, 20 - intermediate transfer belt (an example of an intermediate transfer member), 22 - drive roller, 24 - backup roller, 26 - Secondary transfer roller (an example of a secondary transfer device), 28-fixing device (an example of a fixing device), 30-intermediate transfer body cleaning device, 107-photoreceptor (an example of an image holding body), 108-charging roller (an example of a charging device), 109-exposure device (an example of an electrostatic image forming device), 111-developing device (an example of a developing device), 112-transfer device (an example of a transfer device), 113-photoreceptor cleaning device (an example of a cleaning device), 115-fixing device (an example of a fixing device), 116-mounting guide, 118-opening portion for exposure, 117-housing, 200-processing box, 300-recording paper (an example of a recording medium), P-recording paper (an example of a recording medium). DETAILED DESCRIPTION

[0086] Hereinafter, an embodiment of the present invention will be described. These descriptions and examples illustrate the embodiment and do not limit the scope of the invention.

[0087] In the numerical ranges described in stages in this specification, the upper limit or lower limit described in one numerical range may be replaced by the upper limit or lower limit of another numerical range described in stages. Furthermore, in the numerical ranges described in this specification, the upper limit or lower limit of the numerical range may also be replaced by the value shown in the Examples.

[0088] In this specification, (meth)acrylic acid refers to both acrylic acid and methacrylic acid.

[0089] In this specification, the term "process" includes not only independent processes but also processes that cannot be clearly distinguished from other processes as long as the intended purpose of the process can be achieved.

[0090] Each component may contain multiple corresponding substances.

[0091] 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, the amount refers to the total amount of the multiple substances present in the composition.

[0092] [Toner for electrostatic image development]

[0093] The electrostatic image developing toner (hereinafter also referred to as “toner”) according to the present embodiment includes toner particles containing an amorphous polyester resin as a binder resin and a crystalline resin.

[0094] The toner particles contain an amorphous polyester resin (S) as the amorphous polyester resin, wherein the amorphous polyester resin (S) has at least one of a structural unit derived from an aliphatic dicarboxylic acid represented by structural formula (A) and a structural unit derived from an aliphatic diol represented by structural formula (B), and the total proportion of the structural unit derived from the aliphatic dicarboxylic acid represented by structural formula (A) and the structural unit derived from the aliphatic diol represented by structural formula (B) in all structural units constituting the amorphous polyester resin is 0.5% or more and 10.0% or less in terms of molar ratio.

[0095] In a dynamic viscoelasticity measurement of the toner particles when heated from 30°C to 120°C, a minimum loss tangent tanδ(min) exists at 50°C to 80°C, and the minimum loss tangent tanδ(min) is 0.50 to 1.00.

[0096] The above-described structure enables the toner according to this embodiment to have low-temperature fixing properties and suppress contamination of the edge of the recording medium. The reason for this is presumably as follows.

[0097] Toners are required to have low-temperature fixing properties from the viewpoints of energy conservation and high-speed image formation. By using a crystalline resin, sharp melt properties can be imparted to toner particles, thereby ensuring low-temperature fixing properties.

[0098] On the other hand, the viscoelasticity of melted toner typically reaches a high loss tangent (tan δ), making it viscous. This increases the adhesion between the toner and the fixing member compared to the adhesion between the toner and the recording medium, causing some of the melted toner to adhere to the fixing member. This phenomenon is particularly prone to occur with isolated toner particles, where the cohesive forces between toner particles are ineffective. Although no defects are observed in the image, isolated toner particles may adhere to the fixing member (so-called invisible offset: NVO).

[0099] If the invisible offset occurs repeatedly, the adhered toner accumulates and contaminates the recording medium transport roller, thereby causing contamination at the end of the recording medium.

[0100] Therefore, in the toner involved in this embodiment, an amorphous polyester resin (S) is used, in which the amorphous polyester resin (S) contains at least one of the structural units derived from aliphatic dicarboxylic acid represented by structural formula (A) and the structural units derived from aliphatic diol represented by structural formula (B) at a specific molar ratio relative to all the structural units of all the amorphous polyester resins contained in the toner particles.

[0101] The structural unit derived from an aliphatic dicarboxylic acid represented by the structural formula (A) and the structural unit derived from an aliphatic diol represented by the structural formula (B) are relatively soft sites and can provide relatively soft sites inside the toner particles.

[0102] Therefore, even if there are irregularities on the recording medium surface, the relatively soft areas allow the toner particles to follow the pressure during fixing and easily deform, thereby suppressing invisible offset.

[0103] However, increasing the amount of the structural unit derived from an aliphatic dicarboxylic acid represented by structural formula (A) and the structural unit derived from an aliphatic diol represented by structural formula (B) can provide a large number of soft sites in the toner particles. However, if the amount is increased too much, the soft sites become excessive, increasing adhesion to the fixing member and causing invisible offset. Furthermore, the glass transition temperature (Tg) of the toner particles is excessively lowered, degrading other properties such as thermal stability. Therefore, the total molar ratio of these structural units to all structural units is set to 10% or less.

[0104] Furthermore, in the structural unit derived from an aliphatic dicarboxylic acid represented by the structural formula (A) and the structural unit derived from an aliphatic diol represented by the structural formula (B), "(-CH2-) n The number "n" in the toner is 2 to 12, and the carbon chain length is an appropriate length, which can provide a soft portion in the toner particles and improve the affinity with the crystalline resin. Therefore, low-temperature fixing property and invisible offset suppression become good.

[0105] Furthermore, in dynamic viscoelasticity measurements of toner particles at temperatures rising from 30°C to 120°C, the minimum loss tangent (tan δ (min)) between 50°C and 80°C is set to 0.5 or more and 1.0 or less. This allows for flexible control of toner properties within the 50°C to 80°C temperature range, where toner melting begins. Specifically, by elastically controlling the toner's viscoelasticity during melting at a low loss tangent (tan δ), the adhesion of isolated toner particles to the fixing member can be further reduced, further improving releasability from the fixing member. This suppresses invisible offset and reduces contamination of the edges of the recording medium.

[0106] Based on the above, it is presumed that the toner according to the present embodiment has low-temperature fixing properties and can suppress contamination of the edge of the recording medium due to the above-mentioned configuration.

[0107] Hereinafter, the toner according to this embodiment will be described in detail.

[0108] The toner according to this embodiment includes toner particles and external additives.

[0109] (Dynamic Viscoelasticity of Toner Particles)

[0110] In the dynamic viscoelasticity measurement when the temperature of the toner particles is raised from 30°C to 120°C, a minimum value of the loss tangent tanδ(min) exists at a temperature of 50°C to 80°C, and the minimum value of the loss tangent tanδ(min) is 0.50 to 1.00, for example, preferably 0.60 to 0.90, and more preferably 0.70 to 0.90.

[0111] If the minimum loss tangent value, tanδ(min), is less than 0.50, the viscoelasticity of the melted toner becomes sticky, increasing the adhesion of the isolated toner to the fixing member and reducing its releasability from the fixing member. This results in invisible offset and contamination of the edge of the recording medium.

[0112] If the minimum value of the loss tangent, tan δ (min), exceeds 1.00, the viscoelasticity of the toner during melting becomes excessively elastic, and thus the low-temperature fixing property is deteriorated.

[0113] The ratio of the minimum loss tangent tanδ(min) in the toner particles to the loss tangent tanδ(90) at a temperature of 90°C, tanδ(90) / tanδ(min), is preferably 2.5 or less, more preferably 2.2 or less, and further preferably 2.0 or less.

[0114] When the ratio tan δ(90) / tan δ(min) is 2.5 or less, even when heating is uneven during fixing due to unevenness of the paper, adhesion of isolated toner to the fixing member can be suppressed, thereby suppressing the occurrence of invisible offset.

[0115] Therefore, if the ratio tan δ(90) / tan δ(min) is set within the above range, low-temperature fixing properties are improved and contamination of the edge of the recording medium can be easily suppressed.

[0116] As methods for setting the minimum value of the loss tangent tanδ(min) and the ratio tanδ(90) / tanδ(min) within the above-mentioned range, there can be cited: 1) a method of adding internally added cross-linked resin particles (especially internally added cross-linked resin particles having a specific glass transition temperature) into the toner particles; 2) a method of adjusting the amount of metal ions selected from the group consisting of Al, Mg and Ca in the toner particles to control the amount of cross-linking of the binding resin based on the metal ions, etc.

[0117] The loss tangent tan δ of the toner particles is obtained by measuring the dynamic viscoelasticity when the temperature is increased from 30° C. to 120° C. The details are as follows.

[0118] The toner particles to be measured were formed into tablets at room temperature (25°C) using a press molding machine to prepare a measurement sample. This measurement sample was placed in a rheometer and allowed to stand at 120°C for 20 minutes. The sample was then cooled to 60°C and held at 60°C for 1 hour before being cooled to room temperature. Dynamic viscoelasticity measurements were then performed under the following measurement conditions. The loss tangent (tan δ) was calculated from the storage modulus and loss modulus curves obtained from the measurements.

[0119] -Measurement conditions-

[0120] Measuring device: Rheometer ARES (manufactured by TA Instruments)

[0121] Measuring fixture: 8mm parallel plate

[0122] Gap: Adjust to 3mm

[0123] Frequency: 6.28 rad / s

[0124] Heating conditions: starting temperature = 30°C, ending temperature = 120°C, heating rate = 2°C / min

[0125] Furthermore, since the loss tangent tan δ in toner particles is not affected by external additives, the loss tangent tan δ can be measured by subjecting the toner to dynamic viscoelasticity measurement.

[0126] (Composition of Toner Particles)

[0127] The toner particles contain an amorphous resin and a crystalline resin as a binder resin, and may contain a colorant, a release agent, internally added crosslinked resin particles, and other additives.

[0128] In particular, it is preferable to include internally added crosslinked resin particles in the toner particles because, for example, the above-mentioned loss tangent characteristic can be easily obtained.

[0129] -Binding resin-

[0130] As the binder resin, amorphous polyester resin and crystalline resin are suitable.

[0131] The "crystallinity" of a resin refers to the presence of a clear endothermic peak in differential scanning calorimetry (DSC) rather than a step-like change in endothermic value. Specifically, it refers to the half-width of the endothermic peak being within 10°C when measured at a heating rate of 10°C / min.

[0132] On the other hand, the "amorphous nature" of a resin means that the half-value width exceeds 10° C., a step-like change in endothermic value is observed, or a clear endothermic peak cannot be confirmed.

[0133] The amorphous polyester resin will be described.

[0134] The amorphous polyester resin is a condensation polymer of a polycarboxylic acid and a polyol, that is, an amorphous polyester resin having structural units PC derived from a polycarboxylic acid and structural units PA derived from a polyol.

[0135] Furthermore, the amorphous polyester resin includes a polyester resin (S) having at least one of a structural unit derived from an aliphatic dicarboxylic acid represented by the following structural formula (A) and a structural unit derived from an aliphatic diol represented by the following structural formula (B) as a part of the structural unit PC derived from a polycarboxylic acid and the structural unit PA derived from a polyol.

[0136] [Chemical Formula 2]

[0137]

[0138] In structural formulae (A) and (B), nA and nB each independently represent an integer of 2 or more and 12 or less.

[0139] The total proportion of the structural units derived from aliphatic dicarboxylic acid represented by structural formula (A) and the structural units derived from aliphatic diol represented by structural formula (B) in all the structural units constituting the amorphous polyester resin contained in the toner particles is 0.5% or more and 10.0% or less, for example, preferably 1.5% or more and 8.0% or less, and more preferably 2.5% or more and 6.0% or less, in terms of molar ratio.

[0140] If the combined proportion of these structural units is less than 0.5%, the relatively soft areas within the toner particles are reduced, making it difficult for the toner particles to deform in response to the pressure during fixing. Consequently, invisible offset cannot be suppressed, leading to contamination of the edges of the recording medium. Furthermore, the affinity for crystalline resins decreases, impairing low-temperature fixing performance.

[0141] If the total proportion of the structural units is 10.0% or more, too many relatively soft regions are provided inside the toner particles, thereby increasing adhesion to the fixing member and causing invisible offset.

[0142] The ratio of the total of the structural units derived from an aliphatic dicarboxylic acid represented by the structural formula (A) and the structural units derived from an aliphatic diol represented by the structural formula (B) in all the structural units constituting the amorphous polyester resin is measured as follows.

[0143] The toner is dissolved in a solvent such as tetrahydrofuran (THF) in which the binder resin is soluble to remove insoluble components, and then dried. Furthermore, the amorphous polyester resin and the crystalline resin contained in the binder resin are separated using a solvent in which the amorphous polyester resin is soluble and the crystalline resin is insoluble, utilizing the difference in solubility between the amorphous polyester resin and the crystalline resin in the solvent. After confirming the absence of an endothermic peak derived from the crystalline resin in the obtained amorphous polyester resin using a DSC (differential scanning calorimeter), the amorphous polyester resin is subjected to a separation process. 1 H-NMR measurement. The obtained NMR spectrum is analyzed to determine the chemical shift and integrated value ratio. Based on the chemical shift and integrated value ratio, the total ratio (molar ratio) of the structural units derived from the aliphatic dicarboxylic acid represented by structural formula (A) and the structural units derived from the aliphatic diol represented by structural formula (B) in the amorphous polyester resin is determined.

[0144] From the viewpoint of easy availability and low cost, the amorphous polyester resin (S) is preferably a resin having, for example, only the structural unit derived from an aliphatic dicarboxylic acid represented by the structural formula (A) among the structural units derived from an aliphatic diol represented by the structural formula (B).

[0145] The proportion of the structural unit derived from an aliphatic dicarboxylic acid represented by structural formula (A) in all the structural units derived from carboxylic acid constituting all the amorphous polyester resins contained in the toner particles is, for example, preferably from 2.0% to 15.0% in terms of molar ratio, more preferably from 3.0% to 10.0%, and even more preferably from 3.2% to 9.5%.

[0146] If the proportion of structural units derived from aliphatic dicarboxylic acids represented by structural formula (A) is 2.0% or greater, the relatively soft regions within the toner particles make them more susceptible to deformation due to the pressure during fixation. This makes it difficult to suppress invisible offset, leading to contamination of the edges of the recording medium. Furthermore, the affinity for crystalline resins is enhanced, resulting in improved low-temperature fixability.

[0147] When the proportion of the structural units derived from aliphatic dicarboxylic acid represented by structural formula (A) is 15.0% or less, the relatively soft regions within the toner particles are not excessively imparted, thereby suppressing an excessive decrease in the glass transition temperature (Tg) of the toner particles. Consequently, excessive melting of the toner particles during fixing is suppressed, resulting in improved low-temperature fixing properties.

[0148] The ratio of the structural unit derived from an aliphatic dicarboxylic acid represented by the structural formula (A) is measured as follows.

[0149] The toner is dissolved in a solvent such as tetrahydrofuran (THF) in which the binder resin is soluble to remove insoluble components, and then dried. Furthermore, the amorphous polyester resin and the crystalline resin contained in the binder resin are separated using a solvent in which the amorphous polyester resin is soluble and the crystalline resin is insoluble, utilizing the difference in solubility between the amorphous polyester resin and the crystalline resin in the solvent. After confirming the absence of an endothermic peak derived from the crystalline resin in the obtained amorphous polyester resin using a DSC (differential scanning calorimeter), the amorphous polyester resin is subjected to a separation process. 1 H-NMR measurement: The obtained NMR spectrum is analyzed to determine the chemical shift and the integrated value ratio. From the chemical shift and the integrated value ratio, the proportion (molar ratio) of the structural units derived from the aliphatic dicarboxylic acid represented by the structural formula (A) in the entire amorphous polyester resin is determined.

[0150] From the viewpoint of low-temperature fixing properties and suppression of contamination of the edge of the recording medium, in the amorphous polyester resin (S), the structural unit PA derived from a polycarboxylic acid and the structural unit PC derived from a polyol other than the structural unit derived from an aliphatic dicarboxylic acid represented by the structural formula (A) and the structural unit derived from an aliphatic diol represented by the structural formula (B) are preferably, for example, a structural unit PA derived from an aromatic polycarboxylic acid and a structural unit PC derived from an aromatic polyol, respectively.

[0151] Specifically, from the viewpoint of low-temperature fixing property and suppression of edge contamination of the recording medium, the amorphous polyester resin (S) is preferably a resin having, for example, a structural unit derived from an aliphatic dicarboxylic acid represented by structural formula (A), a structural unit derived from an aromatic polycarboxylic acid, and a structural unit derived from an aromatic polyol. The amorphous polyester resin (S) is particularly preferably a resin having a structural unit derived from an aliphatic dicarboxylic acid represented by structural formula (A), a structural unit derived from an aliphatic diol represented by structural formula (B), a structural unit derived from terephthalic acid, and a structural unit derived from an aromatic polyol.

[0152] Examples of the aliphatic dicarboxylic acid represented by the structural formula (A) include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, sebacic acid, azelaic acid, dodecanedioic acid, and the like, and anhydrides thereof.

[0153] Examples of the aromatic polycarboxylic acid include terephthalic acid, isophthalic acid, phthalic acid, naphthalene dicarboxylic acid, and the like, and anhydrides or lower (for example, having 1 to 5 carbon atoms) alkyl esters thereof.

[0154] Regarding polycarboxylic acids, trivalent or higher carboxylic acids having a cross-linked structure or a branched structure may be used in combination with dicarboxylic acids. Examples of trivalent or higher carboxylic acids include trimellitic acid, pyromellitic acid, anhydrides thereof, or lower (e.g., carbon number 1 to 5) alkyl esters thereof.

[0155] The polyvalent carboxylic acid may be used alone or in combination of two or more.

[0156] Examples of the aliphatic diol represented by the structural formula (B) include ethylene glycol, butanediol, pentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, and undecanediol.

[0157] Examples of the aromatic polyol include ethylene oxide adducts of bisphenol A and propylene oxide adducts of bisphenol A.

[0158] As the polyol, a trivalent or higher polyol having a cross-linked structure or a branched structure may be used in combination with a diol. Examples of the trivalent or higher polyol include glycerin, trimethylolpropane, and pentaerythritol.

[0159] The polyols may be used alone or in combination of two or more.

[0160] The glass transition temperature (Tg) of the amorphous polyester resin is, for example, preferably 50° C. or higher and 80° C. or lower, and more preferably 50° C. or higher and 65° C. or lower.

[0161] The glass transition temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC), more specifically, according to the "extrapolated glass transition onset temperature" method described in JIS K 7121-1987 "Plastics - Determination of Transition Temperatures".

[0162] The weight average molecular weight (Mw) of the amorphous polyester resin is, for example, preferably 5,000 or more and 1,000,000 or less, and more preferably 7,000 or more and 500,000 or less.

[0163] The number average molecular weight (Mn) of the amorphous polyester resin is preferably, for example, 2,000 or more and 100,000 or less.

[0164] The molecular weight distribution Mw / Mn of the amorphous polyester resin is, for example, preferably 1.5 or more and 100 or less, and more preferably 2 or more and 60 or less.

[0165] The weight-average molecular weight and number-average molecular weight were measured by gel permeation chromatography (GPC). GPC-based molecular weight determinations were performed using a TOSOH Corporation GPC HLC-8120GPC as a measuring apparatus and a TOSOH Corporation column TSKgel SuperHM-M (15 cm) in a THF solvent. The weight-average molecular weight and number-average molecular weight were calculated using a molecular weight calibration curve prepared from the measurement results using monodisperse polystyrene standard samples.

[0166] The amorphous polyester resin is obtained by a known production method. Specifically, for example, the polymerization temperature is set to 180° C. to 230° C., and the pressure in the reaction system is reduced as needed to allow the reaction to proceed while removing water or alcohol generated during condensation.

[0167] Furthermore, if the raw monomers are insoluble or incompatible under the reaction temperature conditions, a high-boiling-point solvent may be added as a cosolvent to dissolve them. In this case, the polycondensation reaction proceeds while the cosolvent is distilled off. If a poorly miscible monomer is present, for example, the poorly miscible monomer can be pre-condensed with an acid or alcohol intended to be polycondensed with the monomer, and then polycondensed with the main component.

[0168] Here, the amorphous polyester resin may be used alone or in combination of two or more.

[0169] For example, it is preferable to use two or more amorphous polyester resins having different molecular weights in combination. An example of using two amorphous polyester resins in combination is a low molecular weight form (L form) of the amorphous polyester resin and a high molecular weight form (H form) of the amorphous polyester resin.

[0170] The low molecular weight form (L-form) is preferably an amorphous polyester resin having a weight average molecular weight of 9000 to 20000 as measured by GPC. If the molecular weight is less than 9000, displacement of the high temperature portion is likely to occur, while if the molecular weight is 20000 or more, gloss in the low temperature portion is less likely to appear.

[0171] The high molecular weight body (H body) is preferably an amorphous polyester resin having a polymerization average molecular weight of 25000 to 70000 as measured by GPC. A molecular weight of 70000 or more reduces glossiness in high temperature areas and reduces the increase in fixing temperature.

[0172] The acid value of the amorphous polyester resin used in combination is preferably, for example, about 13 mgKOH / g to 20 mgKOH / g for the low molecular weight form (L form) and about 10 mgKOH / g to 15 mgKOH / g for the high molecular weight form (H form).

[0173] The crystalline resin will be described.

[0174] Examples of the crystalline resin include known crystalline resins such as crystalline polyester resins and crystalline vinyl resins (e.g., polyalkylene resins, long-chain alkyl (meth)acrylate resins). Among these, crystalline polyester resins are preferred from the perspective of ensuring low-temperature fixing properties.

[0175] Examples of the crystalline polyester resin include polycondensates of polycarboxylic acids and polyols. A commercially available crystalline polyester resin may be used, or a synthetic resin may be used.

[0176] Here, in order to easily form a crystal structure, the crystalline polyester resin is preferably a polycondensate of a polymerizable monomer having a linear aliphatic group, rather than a polycondensate of a polymerizable monomer having an aromatic group.

[0177] Examples of the polycarboxylic acid 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., dibasic acids such as phthalic acid, isophthalic acid, terephthalic acid, and naphthalene-2,6-dicarboxylic acid), anhydrides thereof, or lower (e.g., having 1 to 5 carbon atoms) alkyl esters thereof.

[0178] Regarding polycarboxylic acids, trivalent or higher carboxylic acids that have a cross-linked or branched structure may be used in combination with dicarboxylic acids. Examples of trivalent carboxylic acids include aromatic carboxylic acids (e.g., 1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, etc.), their anhydrides, or their lower (e.g., carbon number 1 to 5) alkyl esters.

[0179] As the polycarboxylic acid, a dicarboxylic acid having a sulfonic acid group or a dicarboxylic acid having an ethylenic double bond may be used in combination with these dicarboxylic acids.

[0180] The polyvalent carboxylic acid may be used alone or in combination of two or more.

[0181] Examples of the polyol include aliphatic diols (e.g., linear aliphatic diols having a main chain portion with 7 to 20 carbon atoms). Examples of the aliphatic diol include ethylene glycol, 1,3-propylene glycol, 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-eicosanediol. Among these, preferred aliphatic diols include 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol.

[0182] Regarding the polyol, a trivalent or higher alcohol having a cross-linked structure or a branched structure may be used in combination with the diol. Examples of the trivalent or higher alcohol include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol.

[0183] The polyols may be used alone or in combination of two or more.

[0184] Here, regarding the polyol, for example, the content of the aliphatic diol is preferably 80 mol% or more, and more preferably 90 mol% or more.

[0185] The melting temperature of the crystalline polyester resin is, for example, preferably 50° C. or higher and 100° C. or lower, more preferably 55° C. or higher and 90° C. or lower, and further preferably 60° C. or higher and 85° C. or lower.

[0186] The melting temperature is determined based on the “melting peak temperature” described in the method for determining the melting temperature in JIS K7121-1987 “Methods for determining transition temperatures of plastics” from a DSC curve obtained by differential scanning calorimetry (DSC).

[0187] The weight average molecular weight (Mw) of the crystalline polyester resin is preferably, for example, 6,000 or more and 35,000 or less.

[0188] Similar to the amorphous polyester resin, the crystalline polyester resin can be obtained by, for example, a well-known production method.

[0189] The content of the binder resin is, for example, preferably 40 mass % to 95 mass % inclusive, more preferably 50 mass % to 90 mass % inclusive, and further preferably 60 mass % to 85 mass % inclusive, based on the entire toner particles.

[0190] Furthermore, from the viewpoint of ensuring low-temperature fixing properties and suppressing contamination of the end portions of the recording medium, the content of the crystalline resin relative to the binder resin is, for example, preferably greater than 2 mass % and less than 40 mass %, more preferably greater than 5 mass % and less than 35 mass %, further preferably greater than 10 mass % and less than 30 mass %, and particularly preferably greater than 15 mass % and less than 30 mass %.

[0191] -Colorant-

[0192] Examples of the colorant include carbon black, chrome yellow, Hansa yellow, benzidine yellow, vat yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, vulcan orange, magenta carmine, permanent red, brilliant carmine 3B, brilliant carmine 6B, Dupont Oil Red, pyrazolone red, litho red, rhodamine B Lake, Red Lake C, pigment red, rose Bengal, aniline blue, ultramarine blue, copper oil blue, methylene blue chloride, phthalocyanine blue, pigment blue, phthalocyanine green, and malachite green oxalate; and various dyes such as acridine-based, xanthene-based, azo-based, benzoquinone-based, azine-based, anthraquinone-based, thioindigo-based, dioxazine-based, thiazine-based, azomethine-based, indigo-based, phthalocyanine-based, nigrosine-based, polymethine-based, triphenylmethane-based, diphenylmethane-based, and thiazole-based dyes.

[0193] The coloring agents may be used alone or in combination of two or more.

[0194] The colorant may be a surface-treated colorant as needed, and may be used in combination with a dispersant. Furthermore, multiple colorants may be used in combination.

[0195] The content of the colorant is, for example, preferably 1 mass % or more and 30 mass % or less, and more preferably 3 mass % or more and 15 mass % or less, based on the total mass of the toner particles.

[0196] -Release agent-

[0197] Examples of the release agent include hydrocarbon waxes, natural waxes such as carnauba wax, rice wax, and candelilla wax, synthetic or mineral / petroleum waxes such as montan wax, and ester waxes such as fatty acid esters and montanic acid esters. The release agent is not limited thereto.

[0198] The melting temperature of the release agent is, for example, preferably 50° C. or higher and 110° C. or lower, and more preferably 60° C. or higher and 100° C. or lower.

[0199] The melting temperature is determined based on the “melting peak temperature” described in the method for determining the melting temperature in JIS K7121-1987 “Determination of Transition Temperatures of Plastics” from a DSC curve obtained by differential scanning calorimetry (DSC).

[0200] The content of the releasing agent is, for example, preferably 1 mass % or more and 20 mass % or less, and more preferably 5 mass % or more and 15 mass % or less, based on the total mass of the toner particles.

[0201] -Internally added cross-linked resin particles-

[0202] Internally added crosslinked resin particles are resin particles contained inside toner particles, and refer to resin particles having a bridge structure between specific atoms in the polymer structure of the resin particles.

[0203] The internally added crosslinked resin particles are particles that exist in the toner particles in a state of being incompatible with the binder resin, for example.

[0204] Examples of internally added crosslinked resin particles include crosslinked resin particles crosslinked by ionic bonds (i.e., ionically crosslinked resin particles) and crosslinked resin particles crosslinked by covalent bonds (i.e., covalently crosslinked resin particles). Among these, internally added crosslinked resin particles are preferably crosslinked resin particles crosslinked by covalent bonds.

[0205] Examples of the resin used for internally added 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 alone or in combination of two or more, as needed.

[0206] Among the above resins, the resin used for internally added crosslinked resin particles includes a styrene-(meth)acrylic acid copolymer. Specifically, for example, the resin particles contain 50% or more of a styrene-(meth)acrylic acid copolymer as the main component, preferably 80% or more, more preferably 90% or more, and particularly preferably substantially all of the styrene-(meth)acrylic acid copolymer. Furthermore, the total amount of styrene monomers and (meth)acrylic acid monomers constituting the copolymer is preferably 80% or more, more preferably 90% or more, and particularly preferably 95% or more. The remainder is a crosslinking agent, described below.

[0207] Examples of the styrene-(meth)acrylic acid-based copolymer include resins obtained by polymerizing the following styrene-based monomers and (meth)acrylic acid-based monomers by radical polymerization.

[0208] Examples of the styrene-based monomer include styrene, α-methylstyrene, vinylnaphthalene, alkyl-substituted styrenes having an alkyl chain 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.

[0209] Examples of the (meth)acrylic acid monomer 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, tert-butyl (meth)acrylate, isoamyl (meth)acrylate, and (meth)acrylate. Examples of the present invention include pentyl (meth)acrylate, neopentyl (meth)acrylate, isohexyl (meth)acrylate, isoheptyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, phenyl (meth)acrylate, biphenyl (meth)acrylate, diphenylethyl (meth)acrylate, tert-butylphenyl (meth)acrylate, terphenyl (meth)acrylate, cyclohexyl (meth)acrylate, tert-butylcyclohexyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, methoxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-carboxyethyl (meth)acrylate, (meth)acrylonitrile, and (meth)acrylamide. Among these, for example, n-butyl (meth)acrylate and 2-carboxyethyl (meth)acrylate are preferred.

[0210] In the internally added cross-linked resin particles, examples of the cross-linking agent for cross-linking the resin include 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 trimesic acid, trivinyl trimesic acid, divinyl naphthalate, and divinyl biphenylcarboxylate; divinyl esters of nitrogen-containing aromatic compounds such as divinyl pyridinedicarboxylate; vinyl esters of unsaturated heterocyclic carboxylic acid compounds such as vinyl pyromucate, vinyl furancarboxylate, vinyl pyrrole-2-carboxylate, and vinyl thiophenecarboxylate; butanediol diacrylate, butanediol dimethacrylate, hexanediol diacrylate, hexanediol dimethacrylate, octanediol diacrylate, octanediol dimethacrylate, nonanediol diacrylate, nonanediol dimethacrylate, decanediol di ...acrylate, decanediol diacrylate, decanediol dimethacrylate, decanediol diacrylate, de (Meth)acrylates of linear polyols such as glycol dimethacrylate, dodecanediol diacrylate, and dodecanediol dimethacrylate; (meth)acrylates of branched and substituted polyols such as neopentyl glycol dimethacrylate, 2-hydroxy, and 1,3-diacryloxypropane; polyethylene glycol di(meth)acrylate, polypropylene polyethylene glycol di(meth)acrylates, divinyl succinate, divinyl fumarate, vinyl maleate, and divinyl maleate , divinyl diglycolate, vinyl itaconate, divinyl itaconate, divinyl acetone dicarboxylate, divinyl glutarate, divinyl 3,3'-thiodipropionate, trans-aconitic acid divinyl ester, trans-aconitic acid trivinyl ester, divinyl adipate, divinyl pimelate, divinyl suberate, divinyl azelate, divinyl sebacate, divinyl dodecanedioate, tridecane divinyl ester and the like. The cross-linking agent may be used alone or in combination of two or more.

[0211] Among these, bifunctional alkyl acrylates having an alkylene chain with 6 or more carbon atoms are preferably used as crosslinking agents for crosslinking the resin. That is, the internally added crosslinked resin particles preferably have bifunctional alkyl acrylates as structural units, and the alkylene chain in the bifunctional alkyl acrylate has 6 or more carbon atoms.

[0212] By using internally added crosslinked resin particles having a bifunctional alkyl acrylate as a structural unit and an alkylene chain having 6 or more carbon atoms, a toner can be easily obtained that exhibits appropriate toner deformation during fixing and exhibits particularly good low-temperature fixability. While the internally added crosslinked resin particles have a high crosslink density (i.e., a short distance between crosslinks), their elasticity tends to be excessively high. In contrast, using a bifunctional acrylate having a long alkylene chain as a crosslinking agent results in a low crosslink density (i.e., a long distance between crosslinks), which can prevent the elasticity of the internally added crosslinked resin particles from becoming excessively high.

[0213] From the viewpoint of adjusting the crosslinking density within an appropriate range, the number of carbon atoms in the alkylene chain in the bifunctional alkyl acrylate is, for example, preferably 6 or more, more preferably 6 or more and 12 or less, and even more preferably 8 or more and 12 or less. More specific examples of the bifunctional alkyl acrylate 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 them, 1,10-decanediol diacrylate and 1,10-decanediol dimethacrylate are preferred.

[0214] As another crosslinking agent, for example, 2-carboxyethyl acrylate can be mentioned, and it is preferable to use at least one of the above-mentioned bifunctional alkyl acrylate and 2-carboxyethyl acrylate.

[0215] In addition, when the internally added cross-linked resin particles are polymer particles of a resin particle-forming composition comprising a styrene-based monomer, a (meth) acrylic acid-based monomer, and a cross-linking agent, the fixing properties of the internally added cross-linked resin particles can be controlled by adjusting the amount of the cross-linking agent contained in the composition. For example, by increasing the amount of the cross-linking agent contained in the composition, internally added cross-linked resin particles with good fixing properties can be easily obtained. The content of the cross-linking agent in the composition for forming the internally added cross-linked resin particles is preferably, for example, 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 3.0 parts by mass or less, and even more preferably 0.8 parts by mass or more and 2.5 parts by mass or less, relative to 100 parts by mass of the total of the styrene-based monomer, the (meth) acrylic acid-based monomer, and the cross-linking agent.

[0216] The glass transition temperature Tg of the internally added cross-linked resin particles is, for example, preferably 0° C. or higher and 40° C. or lower, and more preferably 5° C. or higher and 35° C. or lower.

[0217] By setting the glass transition temperature (Tg) of the internally added crosslinked resin particles within the above range, it is easier to control the loss tangent (tan δ) of each toner particle within the above range. As a result, it is easier to suppress contamination of the edge of the recording medium. In addition, low-temperature fixing properties are improved.

[0218] The glass transition temperature Tg of the internally added cross-linked resin particles is determined from a DSC curve obtained by differential scanning calorimetry (DSC). More specifically, it is determined according to the "extrapolated glass transition onset temperature" method described in JIS K 7121-1987, "Plastics - Determination of Transition Temperatures."

[0219] Alternatively, the internally added crosslinked resin particles can be extracted from the toner by dissolving the toner in a solvent such as tetrahydrofuran (THF) in which the binder resin is soluble, recovering the insoluble portion, and then drying the toner.

[0220] In the internally added cross-linked resin particles composed of a styrene-(meth)acrylic acid copolymer, the Tg can be adjusted by adjusting the polymerization conditions of the copolymer.

[0221] The content of the internally added crosslinked resin particles relative to the entire toner is, for example, preferably 2 mass % or more and 20 mass % or less, and more preferably 5 mass % or more and 15 mass % or less.

[0222] By keeping the content of the internally added crosslinked resin particles within the above range, it is easy to control the loss tangent tanδ of each toner particle within the above range. As a result, it is easy to suppress contamination of the edge of the recording medium. In addition, low-temperature fixing properties are improved.

[0223] The average dispersion diameter of the internally added cross-linked resin particles is, for example, preferably 50 nm to 300 nm, more preferably 80 nm to 300 nm, and further preferably 100 nm to 250 nm.

[0224] If the average dispersion diameter of the internally added crosslinked resin particles is within the above range, it is easy to control the loss tangent tanδ of each toner particle within the above range. As a result, it is easy to suppress contamination of the edge of the recording medium. In addition, low-temperature fixing performance is improved.

[0225] The method for measuring the average dispersion diameter of the internally added cross-linked resin particles is as follows.

[0226] The toner particles or toner are mixed with epoxy resin and embedded to solidify the epoxy resin. The obtained solidified material is cut using an ultrathin sectioning device (Ultracut UCT manufactured by Leica) to produce a thin sheet sample having a thickness of more than 80 nm and less than 130 nm. Next, the obtained thin sheet sample is stained with ruthenium tetroxide in a desiccator at 30°C for 3 hours. Then, an SEM image of the stained thin sheet sample is obtained using an ultra-high resolution field emission scanning electron microscope (FE-SEM, manufactured by Hitachi High-Technologies Corporation, S-4800). Since the ease of staining with ruthenium tetroxide is different in the order of release agent, styrene-(meth) acrylic resin, and polyester resin, each component is identified based on the depth caused by the degree of staining. If it is difficult to distinguish the depth based on the state of the sample, the staining time is adjusted.

[0227] In addition, in the cross section of the toner particles, the domain of the colorant is smaller than the domain of the release agent and the domain of the resin particles, and thus can be distinguished based on size.

[0228] In the SEM image, 30 toner cross sections with a maximum length of at least 85% of the toner particle volume average particle diameter were selected, and a total of 100 dyed internally added cross-linked resin particles (i.e., their domains) were observed. The maximum length of each domain was measured, and the maximum length was considered the domain diameter. The average equivalent circle diameter was calculated by arithmetic averaging these diameters. The obtained average equivalent circle diameter was then used as the average dispersed diameter of the internally added cross-linked resin particles.

[0229] The adjustment of the average dispersion diameter of the internally added cross-linked resin particles can be achieved, for example, by controlling the following steps: producing toner particles by agglomeration, adjusting the volume average particle size of the internally added cross-linked resin particles contained in the internally added cross-linked resin particle dispersion used during the production; preparing a plurality of internally added cross-linked resin particle dispersions having different volume average particle sizes and using them in combination.

[0230] -Method for producing internally added cross-linked resin particles-

[0231] As a method for producing internally added cross-linked resin particles, for example, known methods such as emulsion polymerization, melt kneading using a Banbury mixer or kneader, suspension polymerization, and spray drying can be used. However, in order to make the units derived from the styrene-based monomers unevenly present on the particle surface, emulsion polymerization is preferred.

[0232] In the method for producing internally added crosslinked resin particles, for example, it is preferred to use a styrene-based monomer and a (meth)acrylic-based monomer as monomers and polymerize them in the presence of a crosslinking agent.

[0233] In the method for producing internally added crosslinked resin particles, for example, it is preferable to carry out emulsion polymerization multiple times.

[0234] Hereinafter, the method for producing the internally added cross-linked resin particles will be described in more detail.

[0235] The method for producing internally added cross-linked resin particles preferably includes, for example:

[0236] a step of obtaining an emulsion containing a monomer, a cross-linking agent, a surfactant, and water (emulsion preparation step);

[0237] a step of polymerizing the monomers by adding a polymerization initiator to the emulsion and heating the emulsion (a first emulsion polymerization step); and

[0238] A step of polymerizing the monomer by adding an emulsion containing a monomer and a cross-linking agent to the reaction solution after the first emulsion polymerization step and heating the mixture (second emulsion polymerization step).

[0239] Furthermore, in the second emulsion polymerization step, in order to adjust the composition of the particle surface, the ratio of the styrene-based monomer to the (meth)acrylic-based monomer may be changed to prepare an emulsion, and then the emulsion may be added multiple times.

[0240] --Emulsion preparation process--

[0241] This is a step of obtaining an emulsion containing monomers, a crosslinking agent, a surfactant, and water.

[0242] For example, it is preferred to obtain an emulsion by emulsifying a monomer, a crosslinking agent, a surfactant, and water using an emulsifier.

[0243] Examples of emulsifiers include rotary stirrers with propeller-type, anchor-type, paddle-type, or turbine-type stirring blades; static mixers such as static mixers; rotor / stator emulsifiers such as homogenizers and CERAMIX; mill-type emulsifiers with a grinding function; high-pressure emulsifiers such as a Manton-Gaulin pressure emulsifier; high-pressure nozzle-type emulsifiers that generate cavitation under high pressure; high-pressure collision-type emulsifiers such as a microfluidizer that apply shear force by causing liquids to collide with each other under high pressure; ultrasonic emulsifiers that generate cavitation using ultrasonic waves; membrane emulsifiers that emulsify through fine pores, etc.

[0244] As the monomer, for example, a styrene-based monomer and a (meth)acrylic-based monomer are preferably used.

[0245] As the cross-linking agent, the cross-linking agents already described are suitable.

[0246] 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 glycols, alkylphenol ethylene oxide adducts, and polyols. Nonionic surfactants can be used in combination with anionic or cationic surfactants. Among these, anionic surfactants are preferred. Surfactants can be used alone or in combination of two or more.

[0247] The emulsion may contain a chain transfer agent. As the chain transfer agent, there is no particular limitation, and compounds having a mercaptan component can be used. Specifically, for example, alkyl mercaptans such as hexyl mercaptan, heptyl mercaptan, octyl mercaptan, nonyl mercaptan, decyl mercaptan, and dodecyl mercaptan are preferred.

[0248] The mass ratio of the styrene-based monomer to the (meth)acrylic-based monomer in the emulsion (styrene-based monomer / (meth)acrylic-based monomer) is preferably, for example, 0.2 or more and 1.1 or less.

[0249] Furthermore, the content of the cross-linking agent relative to the entire emulsion is preferably, for example, 0.5% by mass or more and 3% by mass or less.

[0250] --First emulsion polymerization step--

[0251] This is a step of adding a polymerization initiator to the emulsion and heating it to polymerize the monomers.

[0252] Here, when performing polymerization, it is preferred that the emulsion (reaction solution) containing the polymerization initiator is stirred using, for example, a stirrer.

[0253] Examples of the stirrer include a rotary stirrer equipped with a propeller-type, anchor-type, paddle-type, or turbine-type stirring blade.

[0254] As the polymerization initiator, for example, ammonium persulfate is preferably used.

[0255] --Second emulsion polymerization step--

[0256] This is a step of polymerizing the monomers by adding an emulsion containing the monomers to the reaction solution after the first emulsion polymerization step and heating the mixture.

[0257] During the polymerization, for example, the reaction solution is preferably stirred in the same manner as in the first emulsion polymerization step.

[0258] In this step, the ratio of the styrene-based monomer to the (meth)acrylic-based monomer in the emulsion containing monomers may be changed, and the emulsion may be added in multiple batches.

[0259] The emulsion containing the monomer is preferably obtained by emulsifying the monomer, a surfactant, and water using an emulsifier, for example.

[0260] -Other additives-

[0261] Examples of other additives include well-known additives such as magnetic materials, charge control agents, and inorganic powders. These additives are contained in the toner particles as internal additives.

[0262] - Characteristics of toner particles, etc. -

[0263] The toner particles preferably contain at least one metal ion selected from the group consisting of Al, Mg, and Ca. The ratio AV1 / M1 of the amount M1 of the metal ions to the acid value AV1 of the binder resin is preferably 1.0×10 3 Above and 4.0×10 3 Below, more preferably 1.5×10 3 Above and 3.8×10 3 Below, more preferably 2.0×10 3 Above and 3.5×10 3 the following.

[0264] By setting AV1 / M1 within the above range, the binder resin is given an appropriate crosslinking structure, making it easier to control the loss tangent tanδ of each toner particle within the above range. As a result, contamination of the edge of the recording medium is easily suppressed. In addition, low-temperature fixability is improved.

[0265] The amount of metal ions relative to the toner particles is, for example, preferably not less than 0.0015 mass % and not more than 0.0150 mass %, and more preferably not less than 0.0020 mass % and not more than 0.0100 mass %.

[0266] Examples of metal ion sources (compounds included as additives in toner particles) include metal salts, inorganic metal salt polymers, and metal complexes. When toner particles are produced by a coagulation method, the metal salts and inorganic metal salt polymers are added to the toner particles as, for example, a coagulant.

[0267] Examples of the metal salt include aluminum sulfate, aluminum chloride, magnesium chloride, magnesium sulfate, calcium chloride, and calcium sulfate.

[0268] Examples of the inorganic metal salt polymer include polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide.

[0269] Examples of the metal complex include metal salts of aminocarboxylic acids. Specific examples of the metal complex include metal salts (e.g., calcium salts, magnesium salts, and aluminum salts) based on known chelating agents such as ethylenediaminetetraacetic acid, propylenediaminetetraacetic acid, nitrilotriacetic acid, triethylenetetraaminehexaacetic acid, and diethylenetriaminepentaacetic acid.

[0270] Furthermore, the source of these metal ions may be added simply as an additive, rather than as a coagulant.

[0271] As metal ions, Al ions are preferred, for example. That is, as a source of metal ions, aluminum salts (for example, aluminum sulfate, aluminum chloride, etc.) and aluminum salt polymers (for example, polyaluminum chloride, polyaluminum hydroxide, etc.) are preferred. Among the sources of metal ions, inorganic metal salt polymers are particularly preferred. Therefore, as a source of metal ions, aluminum salt polymers (for example, polyaluminum chloride, polyaluminum hydroxide, etc.) are particularly preferred.

[0272] The amount of metal ions is determined by quantitatively analyzing the intensity of the fluorescent X-rays of the toner particles. Specifically, for example, a resin and a source of metal ions are first mixed to obtain a resin mixture with a known metal ion concentration. A tablet forming machine with a diameter of 13 mm is used to obtain a particle sample using 200 mg of the resin mixture. The mass of the particle sample is accurately weighed, and the fluorescent X-ray intensity of the particle sample is measured to determine the peak intensity. Similarly, particle samples with a changed amount of the source of metal ions are also measured, and a calibration curve is prepared based on the results. Then, the calibration curve is used to quantitatively analyze the content of metal ions in the toner particles to be measured. In this embodiment, metal ions are not limited to metals in an ionized state in the resin or toner particles, but refer to metal elements measured as fluorescent X-ray intensity.

[0273] Examples of methods for adjusting the amount of metal ions include: 1) adjusting the amount of a metal ion source; 2) when toner particles are produced by a coagulation method, adding a coagulant (e.g., a metal salt or a metal salt polymer) as a metal ion source in the coagulation step, and then adding a chelating agent (e.g., EDTA (ethylenediaminetetraacetic acid), DTPA (diethylenetriaminepentaacetic acid), NTA (nitrilotriacetic acid), etc.) at the end of the coagulation step, forming a metal ion and a complex using the chelating agent, and adjusting the metal ion content by removing the formed complex salt in a subsequent washing step.

[0274] The acid value of the binder resin is measured in accordance with "JIS K 0070 1992 - Test methods for acid value, saponification value, ester value, iodine value, hydroxyl value and unsaponifiable matter of chemical products."

[0275] Alternatively, the binder resin component can be extracted from the toner by dissolving the toner in a solvent such as tetrahydrofuran (THF) in which the binder resin is soluble to remove insoluble components and then drying the toner.

[0276] The toner particles may be toner particles of a single-layer structure, or may be toner particles of a so-called core-shell structure composed of a core (core particle) and a coating layer (shell layer) that covers the core.

[0277] Here, the core-shell toner particles preferably include, for example, a core portion containing a binder resin and internally added crosslinked resin particles and, if necessary, other additives such as a colorant and a release agent, and a coating layer containing a binder resin.

[0278] The volume average particle diameter (D50v) of the toner particles is, for example, preferably 2 μm or more and 10 μm or less, and more preferably 4 μm or more and 8 μm or less.

[0279] Various average particle sizes and various particle size distribution indices of the toner particles are measured using Coulter Multisizer II (manufactured by Beckman Coulter) and ISOTON-II (manufactured by Beckman Coulter) as the electrolyte.

[0280] During measurement, 0.5 mg to 50 mg of a sample is added to 2 ml of a 5% aqueous solution of a surfactant (e.g., preferably sodium alkylbenzenesulfonate) as a dispersant, and this is added to 100 ml to 150 ml of the electrolyte.

[0281] The electrolyte solution containing the sample was dispersed for 1 minute using an ultrasonic disperser, and the particle size distribution of particles with a diameter of 2 μm to 60 μm was measured using a Coulter Multisizer II with a pore diameter of 100 μm. 50,000 particles were sampled.

[0282] For the particle size range (interval) divided based on the particle size distribution to be measured, the volume cumulative distribution and the number cumulative distribution are respectively drawn from the smaller diameter side, and the particle size that will become 16% of the cumulative is defined as the volume particle size D16v and the number particle size D16p, the particle size that will become 50% of the cumulative is defined as the volume average particle size D50v and the cumulative number average particle size D50p, and the particle size that will become 84% of the cumulative is defined as the volume particle size D84v and the number particle size D84p.

[0283] Use these, by (D84v / D16v) 1 / 2 Calculate the volume particle size distribution index (GSDv) by (D84p / D16p)1 / 2 Calculate the particle size distribution index (GSDp).

[0284] The average circularity of the toner particles is, for example, preferably 0.90 or more and 1.00 or less, and more preferably 0.92 or more and 0.98 or less.

[0285] The average circularity of the toner particles is calculated as (circle-equivalent circumference) / (circumference) [(circumference of a circle having the same projected area as the particle image) / (circumference of the particle projected image)]. Specifically, it is a value measured by the following method.

[0286] First, the toner particles to be measured were collected by suction, forming a flattened flow. This flow was then momentarily stroboscoped to capture a particle image as a still image. This particle image was then analyzed using a flow particle image analyzer (FPIA-3000, manufactured by Sysmex Corporation). The average circularity was determined using a sample count of 3500.

[0287] When the toner contains an external additive, the toner (developer) to be measured is dispersed in water containing a surfactant and then subjected to ultrasonic treatment to obtain toner particles from which the external additive has been removed.

[0288] (External additives)

[0289] Examples of external additives include inorganic particles. Examples of inorganic particles include SiO2, TiO2, Al2O3, SrTiO3, CuO, ZnO, SnO2, CeO2, Fe2O3, MgO, BaO, CaO, K2O, Na2O, ZrO2, CaO·SiO2, K2O·(TiO2) n , Al2O3·2SiO2, CaCO3, MgCO3, BaSO4, MgSO4 and other particles.

[0290] As the surface of the inorganic particles of the external additive, for example, hydrophobization treatment is preferably implemented.Hydrophobic treatment is carried out, for example, by impregnating the inorganic particles in a hydrophobization treatment agent.The hydrophobization treatment agent is not particularly limited, and for example, silane coupling agents, silicone oils, titanate coupling agents, aluminum coupling agents, etc. can be cited. They can be used alone or in combination of two or more.

[0291] The amount of the hydrophobizing agent is usually, for example, 1 part by mass or more and 10 parts by mass or less relative to 100 parts by mass of the inorganic particles.

[0292] Examples of external additives include resin particles (polystyrene, polymethyl methacrylate (PMMA), melamine resin, and the like), cleaning activators (for example, metal salts of higher fatty acids such as zinc stearate, and particles of fluorine-based high molecular weight substances).

[0293] The amount of the external additive added is, for example, preferably 0.01% by mass or more and 10% by mass or less, and more preferably 0.01% by mass or more and 6.0% by mass or less, based on the toner particles.

[0294] (Toner Manufacturing Method)

[0295] Next, a method for producing a toner according to this embodiment will be described.

[0296] The toner according to this embodiment is obtained by manufacturing toner particles and then adding an external additive to the toner particles.

[0297] Toner particles can be produced by any of dry methods (e.g., kneading and pulverization methods) or wet methods (e.g., coagulation, suspension polymerization, and dissolution suspension methods). The method for producing toner particles is not particularly limited to these methods, and well-known methods may also be used.

[0298] Among these, for example, it is preferable to obtain toner particles by an aggregation method.

[0299] Specifically, for example, when toner particles are produced by an aggregation method, the toner particles are produced through the following steps:

[0300] a step of mixing a first amorphous resin particle dispersion containing first amorphous resin particles as a binder resin, a crystalline resin particle dispersion containing crystalline resin particles as a binder resin, an internally added crosslinked resin particle dispersion containing internally added crosslinked resin particles, a colorant dispersion containing a colorant, and a release agent particle dispersion containing particles of a release agent (hereinafter also referred to as "release agent particles"), and aggregating the particles and the colorant in the obtained dispersion to form first aggregated particles (a first aggregated particle forming step);

[0301] After obtaining a first aggregated particle dispersion in which first aggregated particles are dispersed, second amorphous resin particles serving as a binder resin are added to the first aggregated particle dispersion to aggregate the second amorphous resin particles on surfaces of the first aggregated particles to form second aggregated particles (a second aggregated particle forming step); and

[0302] A step of heating the second aggregated particle dispersion in which the second aggregated particles are dispersed to fuse and unify the second aggregated particles to form toner particles (fusing and unifying step).

[0303] Here, amorphous polyester resin particles are preferably used as the first amorphous resin particles and the second amorphous resin particles.

[0304] Furthermore, although the present aggregation method is described as a method for producing toner particles containing a binder resin, a colorant, and a release agent, the colorant and the release agent are components contained in the toner particles as necessary.

[0305] Hereinafter, the details of each step will be described.

[0306] -Dispersion Preparation Steps-

[0307] First, various dispersions used in the cohesion method are prepared. Specifically, a first amorphous resin particle dispersion containing first amorphous resin particles as a binder resin, a crystalline resin particle dispersion containing crystalline resin particles, an internally added crosslinked resin particle dispersion containing internally added crosslinked resin particles, a colorant dispersion containing a colorant, a second amorphous resin particle dispersion containing second amorphous resin particles as a binder resin, and a release agent particle dispersion containing release agent particles are prepared.

[0308] In addition, in each dispersion preparation step, the first amorphous resin particles, the second amorphous resin particles, and the crystalline resin particles are referred to as “resin particles” in the description.

[0309] Here, the resin particle dispersion is prepared by, for example, dispersing the resin particles in a dispersion medium using a surfactant.

[0310] Examples of the dispersion medium used for the resin particle dispersion include aqueous media.

[0311] Examples of the aqueous medium include water such as distilled water and ion-exchanged water, and alcohols, etc. These may be used alone or in combination of two or more.

[0312] 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 glycols, alkylphenol ethylene oxide adducts, and polyols. Among these, anionic surfactants and cationic surfactants are particularly useful. Nonionic surfactants can be used in combination with anionic or cationic surfactants.

[0313] The surfactant may be used alone or in combination of two or more.

[0314] In a resin particle dispersion, the resin particles may be dispersed in a dispersion medium using, for example, a general dispersion method such as a rotary shearing homogenizer, a ball mill equipped with media, a sand mill, or a dyno-mill. Depending on the type of resin particles, the resin particles may be dispersed in the resin particle dispersion using, for example, a phase inversion emulsification method.

[0315] The phase inversion emulsification method refers to 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) for neutralization, and then an aqueous medium (W phase) is added to convert the resin from W / O to O / W (so-called phase inversion) to form a discontinuous phase, thereby dispersing the resin into particles in the aqueous medium.

[0316] The volume average particle size of the resin particles dispersed in the resin particle dispersion is, for example, 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 further preferably 0.1 μm or more and 0.6 μm or less.

[0317] The volume average particle size of the resin particles is determined by dividing the particle size distribution obtained by measurement using a laser diffraction particle size distribution analyzer (e.g., LA-700, manufactured by HORIBA, Ltd.) into the resulting particle size ranges (intervals). The cumulative distribution is plotted toward the smaller particle size side, and the particle size at which the cumulative distribution of all particles reaches 50% is determined as the volume average particle size D50v. The volume average particle size of particles in other dispersions is also measured in the same manner.

[0318] The content of the resin particles in the resin particle dispersion is, for example, preferably 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.

[0319] In addition, a colorant dispersion, a release agent particle dispersion, and an internally added crosslinked resin particle dispersion are also prepared in the same manner as the resin particle dispersion. Specifically, the volume average particle size of the particles in the resin particle dispersion, the dispersion medium, the dispersion method, and the particle content are the same for the colorant dispersed in the colorant dispersion, the release agent particles dispersed in the release agent particle dispersion, and the internally added crosslinked resin particles dispersed in the internally added crosslinked resin particle dispersion.

[0320] -First Agglomerated Particle Formation Step-

[0321] Next, the first amorphous resin particle dispersion, the crystalline resin particle dispersion, the internally added crosslinked resin particle dispersion, the colorant dispersion, and the release agent particle dispersion are mixed.

[0322] Then, the first amorphous resin, crystalline resin particles, internally added crosslinked resin particles, colorant and release agent particles are heterogeneously aggregated in the mixed dispersion to form first aggregated particles containing the first amorphous resin, internally added crosslinked resin particles, colorant and release agent particles.

[0323] Specifically, for example, a coagulant is added to a dispersion obtained by mixing a first amorphous resin particle dispersion, a crystalline resin particle dispersion, an internally added cross-linked resin particle dispersion, a colorant dispersion, and a release agent particle dispersion, and the pH of the mixed dispersion is adjusted to be acidic (for example, a pH of 2 or more and 5 or less). After adding a dispersion stabilizer as needed, the temperature is set to a range of 20°C or more and 50°C or less, so that the particles dispersed in the mixed dispersion are agglomerated, thereby forming first agglomerated particles.

[0324] In the first condensed particle formation process, for example, the above-mentioned coagulant can be added at room temperature (for example, 25°C) while stirring the mixed dispersion using a rotary shearing homogenizer, and the pH of the mixed dispersion is adjusted to acidic (for example, pH is greater than 2 and less than 5), and the above-mentioned heating is performed after adding a dispersion stabilizer as needed.

[0325] Examples of coagulants include surfactants with opposite polarity to the surfactant used as a dispersant added to the mixed dispersion, inorganic metal salts, and divalent or higher metal complexes. In particular, when a metal complex is used as a coagulant, the amount of surfactant used is reduced, and the charging characteristics are improved.

[0326] If necessary, an additive that forms a complex or similar bond with the metal ion of the coagulant may be used. As such an additive, a chelating agent may be used.

[0327] Examples of the inorganic metal salt include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate; and inorganic metal salt polymers such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide.

[0328] As the chelating agent, a water-soluble chelating agent can be used. Examples of the chelating agent include hydroxycarboxylic acids such as tartaric acid, citric acid, and gluconic acid, iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), and ethylenediaminetetraacetic acid (EDTA).

[0329] The amount of the chelating agent added is preferably 0.01 to 5.0 parts by mass, and more preferably 0.1 to less than 3.0 parts by mass, relative to 100 parts by mass of the resin particles (first amorphous resin particles, crystalline resin particles, and internally added crosslinked resin particles).

[0330] -Second Agglomerated Particle Formation Step-

[0331] Next, after obtaining the first aggregated particle dispersion in which the first aggregated particles are dispersed, the second amorphous resin particle dispersion in which the second amorphous resin particles are dispersed is added to the first aggregated particle dispersion.

[0332] The second amorphous resin particles may be of the same kind as the first amorphous resin or may be of a different kind.

[0333] Next, in a dispersion of the first agglomerated particles and the second amorphous resin particles, the second amorphous resin particles are agglomerated on the surfaces of the first agglomerated particles. At this time, a dispersion of release agent particles may be added to agglomerate the second amorphous resin particles and the release agent particles on the surfaces of the first agglomerated particles. Specifically, for example, in the first agglomerated particle formation step, when the first agglomerated particles have reached a target particle size, the second amorphous resin particle dispersion is added to the first agglomerated particle dispersion, and the mixture is heated below the glass transition temperature of the second amorphous resin particles.

[0334] Then, by adjusting the pH of the dispersion liquid to a range of approximately 6.5 or higher and 8.5 or lower, the aggregation is stopped.

[0335] In this manner, second aggregated particles are obtained in which the second amorphous resin particles are aggregated so as to adhere to the surfaces of the first aggregated particles.

[0336] -Fusion / unification process-

[0337] Next, the second agglomerated particle dispersion in which the second agglomerated particles are dispersed is heated, for example, to a temperature above the glass transition temperature of the first and second amorphous resin particles (for example, a temperature 10 to 30°C higher than the glass transition temperature of the first and second amorphous resin particles) to fuse / unify the second agglomerated particles, thereby forming toner particles.

[0338] Through the above steps, toner particles can be obtained.

[0339] In the above-described aggregation and unification method, the first aggregated particles may be fused and unified to form toner particles without performing the second aggregated particle formation step. Furthermore, the second aggregated particle formation step may be repeated multiple times.

[0340] Furthermore, in the second aggregated particle forming step, a crystalline resin particle dispersion may be used, and an internally added cross-linked resin particle dispersion may also be used.

[0341] Here, after the fusion / unification step is completed, the toner particles formed in the solution are subjected to a known washing step, a solid-liquid separation step, and a drying step to obtain dry toner particles.

[0342] The washing step is not particularly limited, but from the perspective of chargeability, it is preferred to fully perform displacement washing with ion-exchanged water. Furthermore, the solid-liquid separation step is not particularly limited, but from the perspective of productivity, suction filtration, pressure filtration, etc. are preferably performed. Furthermore, the drying method is not particularly limited, but from the perspective of productivity, freeze drying, airflow drying, fluidized bed drying, vibrating fluidized bed drying, etc. are preferably performed.

[0343] The toner according to this embodiment is produced, for example, by adding an external additive to the obtained dry toner particles and mixing them. Mixing is preferably performed using, for example, a V-blender, Henschel mixer, or Lödige mixer. Furthermore, if necessary, a vibrating screen or pneumatic screen can be used to remove coarse toner particles.

[0344] <Electrostatic image developer>

[0345] The electrostatic image developer according to this embodiment includes at least the toner according to this embodiment.

[0346] The electrostatic image developer according to the present embodiment may be a one-component developer containing only the toner according to the present embodiment, or a two-component developer in which the toner and a carrier are mixed.

[0347] The carrier is not particularly limited, and known carriers may be used. Examples of the carrier include coated carriers in which a core material composed of magnetic powder is coated with a coating resin; magnetic powder-dispersed carriers in which magnetic powder is dispersed or blended in a matrix resin; and resin-impregnated carriers in which porous magnetic powder is impregnated with a resin.

[0348] Furthermore, the magnetic powder dispersed carrier and the resin impregnated carrier may be a carrier in which the constituent particles of the carrier serve as a core material and the core material is coated with a coating resin.

[0349] Examples of the magnetic powder include magnetic metals such as iron, nickel, and cobalt, and magnetic oxides such as ferrite and magnetite.

[0350] Examples of the coating resin and matrix resin include styrene-(meth)acrylic resin; polyolefin resins such as polyethylene resin and polypropylene resin; polyvinyl or polyvinylidene resins such as polystyrene, (meth)acrylic resin, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether, and polyvinyl ketone; vinyl chloride-vinyl acetate copolymer; linear silicone resin composed of an organic siloxane bond or a modified product thereof; fluororesins such as polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, and polychlorotrifluoroethylene; polyester; polyurethane; polycarbonate; amino resins such as urea-formaldehyde resin; epoxy resin, etc.

[0351] The coating resin and the matrix resin preferably contain, for example, a (meth)acrylic resin, more preferably contain 50% by mass or more of the (meth)acrylic resin relative to the total mass of the resin, and even more preferably contain 80% by mass or more of the (meth)acrylic resin relative to the total mass of the resin.

[0352] In particular, the coating resin and the matrix resin preferably contain, for example, an alicyclic (meth)acrylic resin as the (meth)acrylic resin.

[0353] Furthermore, the coating resin and the matrix resin may contain other additives such as conductive particles.

[0354] Examples of the conductive particles include particles of metals such as gold, silver, and copper, carbon black, titanium oxide, zinc oxide, tin oxide, barium sulfate, aluminum borate, and potassium titanate.

[0355] Here, in order to coat the surface of the core material with a coating resin, a coating method using a coating layer forming solution prepared by dissolving the coating resin and various additives added as needed in an appropriate solvent can be cited. The solvent is not particularly limited and can be selected taking into account the coating resin used, coating suitability, etc.

[0356] Specific resin coating methods include an immersion method in which the core material is immersed in a coating layer forming solution, a spraying method in which the coating layer forming solution is sprayed onto the surface of the core material, a fluidized bed method in which the coating layer forming solution is sprayed while the core material is floating using flowing air, and a kneading coating method in which the core material of the carrier and the coating layer forming solution are mixed in a kneading coater and the solvent is removed.

[0357] The mixing ratio (mass ratio) of the toner and the carrier in the two-component developer is, for example, preferably toner:carrier=1:100 to 30:100, and more preferably 3:100 to 20:100.

[0358] <Image Forming Apparatus / Image Forming Method>

[0359] The image forming apparatus and image forming method according to this embodiment will be described.

[0360] The image forming apparatus according to this embodiment includes: an image holder; a charging device for charging the surface of the image holder; an electrostatic image forming device for forming an electrostatic image on the charged surface of the image holder; a developing device for storing an electrostatic image developer and developing the electrostatic image formed on the surface of the image holder into a toner image using the electrostatic image developer; a transfer device for transferring the toner image formed on the surface of the image holder to the surface of a recording medium; and a fixing device for fixing the toner image transferred to the surface of the recording medium. The electrostatic image developer according to this embodiment is used as the electrostatic image developer.

[0361] In the image forming device involved in this embodiment, an image forming method (the image forming method involved in this embodiment) is implemented, which includes the following processes: a charging process, in which the surface of the image retaining body is charged; an electrostatic image forming process, in which an electrostatic image is formed on the surface of the charged image retaining body; a developing process, in which the electrostatic image formed on the surface of the image retaining body is developed into a toner image using the electrostatic image developer involved in this embodiment; a transfer process, in which the toner image formed on the surface of the image retaining body is transferred to the surface of the recording medium; and a fixing process, in which the toner image transferred to the surface of the recording medium is fixed.

[0362] The image forming device involved in this embodiment is applicable to the following well-known image forming devices: a device of a direct transfer method in which a toner image formed on the surface of an image retaining body is directly transferred to a recording medium; a device of an intermediate transfer method in which a toner image formed on the surface of an image retaining body is transferred to the surface of an intermediate transfer body for the first time, and the toner image transferred to the surface of the intermediate transfer body is transferred to the surface of a recording medium for the second time; a device having a cleaning device for cleaning the surface of the image retaining body after transferring the toner image but before charging; a device having an electrostatic elimination device for eliminating static electricity by irradiating the surface of the image retaining body with electrostatic elimination light after transferring the toner image and before charging, etc.

[0363] In the case of an intermediate transfer method device, the transfer device may, for example, have the following structure: an intermediate transfer body, on the surface of which a toner image is transferred; a primary transfer device, which transfers the toner image formed on the surface of the image retaining body to the surface of the intermediate transfer body for the primary transfer; and a secondary transfer device, which transfers the toner image transferred to the surface of the intermediate transfer body for the secondary transfer to the surface of the recording medium.

[0364] In addition, in the image forming apparatus involved in this embodiment, for example, the portion including the developing device may be a cartridge structure (processing cartridge) that is detachably mounted on the image forming apparatus. As the processing cartridge, for example, a processing cartridge having a developing device that accommodates the electrostatic image developer involved in this embodiment may be preferably used.

[0365] Hereinafter, an example of the image forming apparatus according to the present embodiment is shown, but the present invention is not limited thereto. In addition, the main parts shown in the drawings will be described, and the description of the other parts will be omitted.

[0366] Figure 1 FIG. 1 is a diagram schematically showing the configuration of an image forming apparatus according to this embodiment.

[0367] Figure 1 The image forming apparatus shown includes first to fourth electrophotographic image forming units 10Y, 10M, 10C, and 10K that output images in 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, separated from each other by a predetermined distance in the horizontal direction. Alternatively, these units 10Y, 10M, 10C, and 10K may be process cartridges that are attachable to and detachable from the image forming apparatus.

[0368] An intermediate transfer belt 20, serving as an intermediate transfer member, extends above each unit 10Y, 10M, 10C, and 10K in the drawing. The intermediate transfer belt 20 is wound around a drive roller 22 and a support roller 24, which are arranged to be spaced apart from each other in the left-to-right direction in the drawing, and travels from the first unit 10Y toward the fourth unit 10K. The support roller 24 is biased away from the drive roller 22 by a spring (not shown), thereby applying tension to the intermediate transfer belt 20 wound around the drive roller 22. Furthermore, an intermediate transfer member cleaning device 30 is provided on the outer circumference of the intermediate transfer belt 20, facing the drive roller 22.

[0369] In addition, the toners including the four colors of yellow, magenta, cyan and black contained in the toner cartridges 8Y, 8M, 8C and 8K are supplied to the developing devices (an example of a developing device) 4Y, 4M, 4C and 4K of each unit 10Y, 10M, 10C and 10K respectively.

[0370] The first to fourth units 10Y, 10M, 10C, and 10K have the same structure. Therefore, the first unit 10Y, which forms a yellow image and is located upstream in the direction of travel of the intermediate transfer belt, will be described as a representative unit. Components identical to those of the first unit 10Y will be designated with magenta (M), cyan (C), and black (K) instead of yellow (Y), and the description of the second to fourth units 10M, 10C, and 10K will be omitted.

[0371] The first unit 10Y includes a photoreceptor 1Y, which functions as an image holder. Sequentially arranged around the photoreceptor 1Y are: a charging roller (an example of a charging device) 2Y, which charges the surface of the photoreceptor 1Y to a predetermined potential; an exposure device (an example of an electrostatic image forming device) 3, which exposes the charged surface to a laser beam 3Y based on a color-decomposed image signal to form an electrostatic image; a developing device (an example of a developing device) 4Y, which supplies charged toner to the electrostatic image to develop the electrostatic image; a primary transfer roller (an example of a primary transfer device) 5Y, which transfers the developed toner image to the intermediate transfer belt 20; and a photoreceptor cleaning device (an example of a cleaning device) 6Y, which removes toner remaining on the surface of the photoreceptor 1Y after the primary transfer.

[0372] The primary transfer roller 5Y is disposed inside the intermediate transfer belt 20 and is positioned opposite the photoreceptor 1Y. Furthermore, each of the primary transfer rollers 5Y, 5M, 5C, and 5K is connected to a bias power supply (not shown) for applying a primary transfer bias. Each bias power supply is controlled by a control unit (not shown) to vary the transfer bias applied to each primary transfer roller.

[0373] Next, the operation of forming a yellow image in the first unit 10Y will be described.

[0374] First, before the operation, the surface of the photoreceptor 1Y is charged to a potential of -600 V to -800 V by the charging roller 2Y.

[0375] The photoreceptor 1Y is conductive (e.g., volume resistivity at 20°C: 1×10 -6 The photosensitive layer is formed by laminating a photosensitive layer on a substrate (with a resistance of 100 Ω·cm or less). This photosensitive layer typically has a high electrical resistance (the resistance of a typical resin), but when irradiated with laser beam 3Y, the specific electrical resistance of the portion irradiated by the laser beam changes. Therefore, based on yellow image data sent from a control unit (not shown), laser beam 3Y is output via exposure device 3 to the surface of the charged photoreceptor 1Y. Laser beam 3Y irradiates the photosensitive layer on the surface of photoreceptor 1Y, forming an electrostatic image of a yellow image pattern on the surface of photoreceptor 1Y.

[0376] An electrostatic image refers to an image formed on the surface of the photoreceptor 1Y by charging, and is a so-called negative latent image. It is formed by the resistivity of the irradiated portion of the photosensitive layer being reduced by the laser beam 3Y, and the charged charge on the surface of the photoreceptor 1Y flowing, while on the other hand, the charge on the portion not irradiated by the laser beam 3Y remains.

[0377] As the photoreceptor 1Y travels, the electrostatic image formed on the photoreceptor 1Y rotates to a predetermined developing position, where the developing device 4Y converts the electrostatic image on the photoreceptor 1Y into a visible image (developed image) as a toner image.

[0378] The developing device 4Y contains, for example, an electrostatic image developer containing at least yellow toner and a carrier. The yellow toner is triboelectrically charged by being stirred within the developing device 4Y, resulting in a charge of the same polarity (negative) as the charge on the photoreceptor 1Y and being retained on the developer roller (an example of a developer retainer). The surface of the photoreceptor 1Y then passes through the developing device 4Y, whereupon the yellow toner electrostatically adheres to the de-electrostaticized latent image on the surface of the photoreceptor 1Y, thereby developing the latent image with the yellow toner. The photoreceptor 1Y, with the yellow toner image formed on it, continues to travel at a predetermined speed, and the toner image developed on the photoreceptor 1Y is transported to a predetermined primary transfer position.

[0379] When the yellow toner image on the photoreceptor 1Y is transported to the primary transfer position, a primary transfer bias is applied to the primary transfer roller 5Y. Electrostatic force from the photoreceptor 1Y toward the primary transfer roller 5Y acts on the toner image, transferring the toner image on the photoreceptor 1Y to the intermediate transfer belt 20. The transfer bias applied at this time has a polarity (+) opposite to the polarity (-) of the toner, and is controlled to, for example, +10 μA by a control unit (not shown) in the first unit 10Y.

[0380] On the other hand, the toner remaining on the photoreceptor 1Y is removed and recovered by the photoreceptor cleaning device 6Y.

[0381] Furthermore, the primary transfer bias applied to the primary transfer rollers 5M, 5C, and 5K in and after the second unit 10M is also controlled in accordance with the first unit.

[0382] In this manner, the intermediate transfer belt 20 to which the yellow toner image has been transferred by the first unit 10Y is sequentially transported through the second to fourth units 10M, 10C, and 10K, so that the toner images of the respective colors are superimposed and multi-transferred.

[0383] The intermediate transfer belt 20, to which the four-color toner images have been multiply transferred by the first through fourth units, reaches the secondary transfer section, which is comprised of the intermediate transfer belt 20, a backup roller 24 in contact with the inner surface of the intermediate transfer belt, and a secondary transfer roller (an example of a secondary transfer device) 26 disposed on the outer circumference of the intermediate transfer belt 20. Meanwhile, recording paper (an example of recording medium) P is fed into the gap between the secondary transfer roller 26 and the intermediate transfer belt 20 via a feed mechanism at a predetermined timing, and a secondary transfer bias is applied to the backup roller 24. The applied transfer bias has a (-) polarity, the same as the polarity of the toner (-). Electrostatic force from the intermediate transfer belt 20 toward the recording paper P acts on the toner images, transferring the toner images on the intermediate transfer belt 20 to the recording paper P. The secondary transfer bias is determined by the resistance detected by a resistance detection device (not shown) that detects the resistance of the secondary transfer section and is voltage-controlled.

[0384] Then, the recording paper P is fed into a pressure-contact portion (nip portion) of a pair of fixing rollers in a fixing device (an example of a fixing device) 28 , where the toner image is fixed on the recording paper P, thereby forming a fixed image.

[0385] Examples of the recording paper P to which the toner image is transferred include plain paper used in electrophotographic copy machines, printers, etc. Examples of the recording medium include OHP sheets and the like in addition to the recording paper P.

[0386] 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 a resin or coated paper for printing can be preferably used.

[0387] The recording paper P on which the color image has been fixed is conveyed toward the discharge portion, thereby completing a series of color image forming operations.

[0388] <Process Cartridge / Toner Cartridge>

[0389] The process cartridge according to this embodiment will be described.

[0390] The process cartridge according to this embodiment is provided with a developing device and is detachably mounted on an image forming apparatus. The developing device accommodates the electrostatic image developer according to this embodiment and develops the electrostatic image formed on the surface of the image holder into a toner image using the electrostatic image developer.

[0391] The process cartridge according to this embodiment is not limited to the above-described structure, and may include a developing device and, if necessary, at least one other device selected from an image holder, a charging device, an electrostatic image forming device, and a transfer device.

[0392] Hereinafter, an example of the process cartridge according to the present embodiment is shown, but the present invention is not limited thereto.

[0393] Figure 2 It is a diagram schematically showing the structure of a process cartridge according to this embodiment.

[0394] Figure 2 The processing box 200 shown is constructed by, for example, integrally combining and holding a photosensitive body 107 (an example of an image holding body), a charging roller 108 (an example of a charging device) provided around the photosensitive body 107, a developing device 111 (an example of a developing device), and a photosensitive body cleaning device 113 (an example of a cleaning device) using a housing 117 having a mounting guide 116 and an opening 118 for exposure, and is made into a box.

[0395] in addition, Figure 2 109 denotes an exposure device (an example of an electrostatic image forming device), 112 denotes a transfer device (an example of a transfer device), 115 denotes a fixing device (an example of a fixing device), and 300 denotes recording paper (an example of a recording medium).

[0396] Next, the toner cartridge according to this embodiment will be described.

[0397] The toner cartridge according to the present embodiment contains the toner according to the present embodiment and is attachable to and detachable from an image forming apparatus. The toner cartridge contains replenishing toner for supplying to a developing device provided in the image forming apparatus.

[0398] in addition, Figure 1 The image forming apparatus shown has a structure in which toner cartridges 8Y, 8M, 8C, and 8K are detachably mounted. The developing devices 4Y, 4M, 4C, and 4K are connected to the toner cartridges corresponding to the respective developing devices (colors) via toner supply tubes (not shown). When the toner contained in a toner cartridge becomes low, the toner cartridge is replaced.

[0399] Example

[0400] Hereinafter, examples will be described, but the present invention is not limited to these examples. In the following description, "parts" and "%" are all based on mass unless otherwise specified.

[0401] [Preparation of emulsions (1-1) to (1-2)]

[0402] <Emulsion (1-1)>

[0403] Styrene: 80 parts

[0404] n-Butyl acrylate: 120 parts

[0405] 1,10-Decanediol diacrylate (crosslinking agent): 4 parts

[0406] Anionic surfactant (NEWCOL271A, manufactured by Nippon Nyukazai Co., Ltd.): 2.2 parts

[0407] Ion exchange water: 197.8 parts

[0408] The above materials were placed in a mixing container equipped with a stirring device and stirred to prepare an emulsion (1-1).

[0409] <Emulsion (1-2)>

[0410] Styrene: 75 parts

[0411] n-Butyl acrylate: 25 parts

[0412] 1,10-Decanediol diacrylate (crosslinking agent): 1.0 part

[0413] Anionic surfactant (NEWCOL271A): 1.1 parts

[0414] Ion exchange water: 97.7 parts

[0415] The above materials were placed in a mixing container equipped with a stirring device and stirred to prepare an emulsion (1-2).

[0416] [Preparation of internally added cross-linked resin particle dispersion (1)]

[0417] After nitrogen was purged in the reaction vessel via a nitrogen inlet tube, 0.5 parts of anionic surfactant (NEWCOL 271A) and 200 parts of ion-exchanged water were added to the reaction vessel equipped with a stirrer and nitrogen inlet tube. The reaction solution was heated in an oil bath while stirring to a temperature of 65°C. After adding 10 parts of emulsion (1-1), 10 parts of an aqueous ammonium persulfate solution adjusted to a concentration of 10% by mass was further added and maintained for 30 minutes.

[0418] Then, while maintaining the temperature of the reaction solution at 65° C., 390 parts of the emulsion (1-1) were gradually added dropwise to the reaction container using a pump over 60 minutes. Furthermore, 200 parts of the emulsion (1-2) were added dropwise over 30 minutes.

[0419] After the addition was completed, the mixture was maintained for 60 minutes, and then 2 parts of 10% by mass ammonium persulfate were added. The mixture was maintained for another 3 hours and then cooled to room temperature. Deionized water was then added to give a solid content concentration of 20% by mass to prepare an internally added crosslinked resin particle dispersion (1).

[0420] The volume average particle size of the obtained resin particles was 165 nm, and the glass transition temperature measured by a differential scanning calorimeter was 17°C.

[0421] [Preparation of dispersions of internally added cross-linked resin particles (2) to (7)]

[0422] Internally added crosslinked resin particle dispersions (2) to (7) were prepared in the same manner as the internally added crosslinked resin particle dispersion (1) except that the conditions were changed to those shown in Table 1.

[0423] [Preparation of amorphous polyester resin particle dispersion (1)]

[0424] Terephthalic acid: 25 parts by mole

[0425] Isophthalic acid: 19 parts by mole

[0426] Adipic acid: 3 molar parts

[0427] Trimellitic anhydride: 2 mol parts

[0428] Bisphenol A propylene oxide 2 mole adduct: 31 moles

[0429] Bisphenol A propylene oxide 3 mole adduct: 20 moles

[0430] The above materials were placed in a reaction vessel equipped with a stirring device, a nitrogen inlet pipe, a temperature sensor, and a distillation 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. Subsequently, a dehydration condensation reaction was continued at 240°C for 3 hours, and then cooled to obtain an amorphous polyester resin (1).

[0431] The amorphous polyester resin (1) had an acid value of 10, a glass transition temperature of 61° C., and a weight average molecular weight Mw of 25,000.

[0432] Amorphous polyester resin (1): 100 parts

[0433] Methyl ethyl ketone: 60 parts

[0434] Isopropyl alcohol: 10 parts

[0435] 10% ammonia solution: 3.5 parts

[0436] The above materials were placed in a jacketed reaction vessel equipped with a condenser, a thermometer, a water dripping device, and an anchor wing. The amorphous polyester resin (1) was dissolved while being stirred and mixed at 100 rpm in a water-circulating thermostatic bath while maintaining the liquid temperature at 50°C. Subsequently, the water-circulating thermostatic bath was set to 40°C, and a total of 300 parts of ion-exchanged water maintained at 40°C was added dropwise at a rate of 3 parts / minute to effect phase inversion, thereby producing an emulsion.

[0437] The obtained emulsion was placed in an eggplant-shaped flask and placed in an evaporator equipped with a vacuum control unit via a trap ball. The eggplant-shaped flask was heated in a 60°C hot water bath while rotating, and the pressure was reduced to 7 kPa while paying attention to boiling. After removing the solvent, the pressure was returned to normal pressure and the eggplant-shaped flask was water-cooled to obtain a dispersion. Ion-exchanged water was added to the obtained dispersion to obtain an amorphous polyester resin particle dispersion (1) with a solid content of 20% by mass. The volume average particle size of the amorphous polyester resin particles in the amorphous polyester resin particle dispersion (1) was 180 nm.

[0438] [Preparation of Amorphous Polyester Resin Particle Dispersions (2) to (19)]

[0439] Amorphous polyester resin particle dispersions (2) to (19) were prepared in the same manner as in the amorphous polyester resin particle dispersion (1), except that the conditions were changed to those shown in Table 2.

[0440] In addition, the details of the abbreviations in Table 2 are as follows.

[0441] TPA: terephthalic acid

[0442] IPA: Isophthalic acid

[0443] TMA: trimellitic anhydride

[0444] BPA-2PO: Bisphenol A propylene oxide 2 mole adduct

[0445] BPA-3PO: Bisphenol A propylene oxide 3 mole adduct

[0446] BPA-2EO: Bisphenol A ethylene oxide 2 mole adduct

[0447] Structure A: A monomer for forming the structural unit derived from an aliphatic dicarboxylic acid represented by the structural formula (A) (i.e., an aliphatic dicarboxylic acid)

[0448] Structure B: Monomer for forming the structural unit derived from an aliphatic diol represented by structural formula (B) (i.e., aliphatic diol)

[0449] [Preparation of Crystalline Polyester Resin Particle Dispersion (1)]

[0450] Dodecanedioic acid: 50 mol parts

[0451] 1,6-Hexanediol: 50 parts by mole

[0452] The above materials were placed in a reaction vessel equipped with a stirring device, a nitrogen inlet pipe, a temperature sensor, and a distillation column. The temperature was raised to 160°C over 1 hour, and 0.8 parts of dibutyltin oxide were added relative to 100 parts of the above materials. While distilling off the generated water, the temperature was raised to 180°C over 6 hours, maintained at 180°C, stirred for 5 hours, and refluxed in the vessel to react. Then, the temperature was gradually raised to 230°C under reduced pressure (3 kPa), maintained at 230°C, and stirred for 2 hours. Then, the reactant was cooled. After cooling, solid-liquid separation was performed, and the solid matter was dried to obtain a crystalline polyester resin (1). The acid value of the crystalline polyester resin (1) was 8.8, and the weight-average molecular weight was 29,000.

[0453] Crystalline polyester resin (1): 100 parts

[0454] Methyl ethyl ketone: 70 parts

[0455] Isopropyl alcohol: 12 parts

[0456] 10% ammonia solution: 3 parts

[0457] The above materials were placed in a jacketed reaction vessel equipped with a condenser, a thermometer, a water dripping device, and an anchor wing. While maintaining the liquid temperature at 80°C in a water-circulating thermostatic bath, the crystalline polyester resin (1) was dissolved while being stirred and mixed at 100 rpm. Subsequently, the water-circulating thermostatic bath was set to 60°C, and a total of 300 parts of ion-exchanged water maintained at 60°C was added dropwise at a rate of 3 parts / minute to effect phase inversion, thereby obtaining an emulsion.

[0458] The obtained emulsion was placed in an eggplant-shaped flask and placed in an evaporator equipped with a vacuum control unit via a trap ball. The eggplant-shaped flask was heated in a 60°C hot water bath while rotating, and the pressure was reduced to 7 kPa while paying attention to boiling. After removing the solvent, the pressure was returned to normal pressure and the eggplant-shaped flask was water-cooled to obtain a dispersion. Ion-exchanged water was added to the dispersion to obtain a crystalline polyester resin particle dispersion (1) having a solid content of 20% by mass. The volume average particle size of the crystalline polyester resin particles in the crystalline polyester resin particle dispersion (1) was 160 nm.

[0459] [Preparation of Colorant Dispersion]

[0460] Carbon black (Regel 330, manufactured by Cabot Corporation): 110 parts

[0461] Anionic surfactant (NEOPELEX G-65, Kao Corporation): 6 parts

[0462] Ion exchange water: 300 parts

[0463] The above materials were mixed and dispersed for 10 minutes using a homogenizer (ULTRA TURRAX T50, manufactured by IKA). Ion-exchanged water was added to the resulting dispersion to obtain a colorant dispersion having a solids content of 20% by mass. The volume average particle size of the colorant particles in the colorant dispersion was 220 nm.

[0464] [Preparation of Release Agent Particle Dispersion]

[0465] Fischer-Tropsch wax (SASOLWAX H1, SASOL): 100 parts

[0466] Anionic surfactant (NEOPELEX G-65): 6 parts

[0467] Ion exchange water: 300 parts

[0468] The above materials were mixed, heated to 100°C, and dispersed using a homogenizer (ULTRA TURRAX T50). Furthermore, the mixture was dispersed using a Manton-Gaulin high-pressure homogenizer (manufactured by Gaulin). Ion-exchanged water was added to the dispersion to obtain a release agent particle dispersion having a solid content of 20% by mass.

[0469] The volume average particle size of the release agent particles in the release agent particle dispersion was 230 nm.

[0470] [Example 1]

[0471] (Preparation of Toner 1)

[0472] Amorphous polyester resin particle dispersion (1) (solid content 20% by mass): 61.7 parts

[0473] Internally added cross-linked resin particle dispersion (1) (solid content 20% by mass): 10 parts

[0474] Crystalline polyester resin particle dispersion (1) (solid content 20% by mass): 15.4 parts

[0475] Colorant dispersion (solid content 20% by mass): 6.9 parts

[0476] Release agent particle dispersion (solid content 20% by mass): 6 parts

[0477] Anionic surfactant (ELEMINOL MON-2): 1.6 parts

[0478] Ion exchange water: 80 parts

[0479] The above materials were placed in a reaction vessel equipped with a thermometer, pH meter, and stirrer. The mixture was stirred at 150 rpm for 30 minutes while maintaining the temperature of the reaction vessel at 20°C. Subsequently, 0.3N nitric acid aqueous solution was added to adjust the pH to 5.0. After dispersion using a homogenizer (ULTRA TURRAX T50), 12 parts of a 1% aluminum sulfate aqueous solution was added. The mixture was then heated to 45°C at a rate of 0.4°C / min while stirring and maintained for 30 minutes.

[0480] Next, 29 parts of amorphous polyester resin particle dispersion (1) were added and the mixture was maintained for 30 minutes. Subsequently, 0.62 parts of CHELEST 40 (manufactured by CHELEST CORPORATION, content 40%) were added. A 0.1N sodium hydroxide aqueous solution was then added to adjust the pH to 8.5, and the mixture was maintained for 15 minutes. The mixture was then heated to 80°C at a rate of 1°C / min while continuously stirring and maintained at 80°C for 5 hours. The mixture was then cooled, solid-liquid separated, and the solid matter was washed with ion-exchanged water. The mixture was then dried in a freeze vacuum dryer for 24 hours to obtain toner particles (1) having a volume average particle size of 5.5 μm.

[0481] Toner 1 was obtained by mixing 100 parts of the toner particles (1) and 2.0 parts of hydrophobic silica (manufactured by NIPPON AEROSIL CO., LTD.: trade name RY200) using a Henschel mixer.

[0482] [Examples 2 to 38 and Comparative Examples 1 to 6]

[0483] (Production of Toners 2 to 38 and Toners C1 to C6)

[0484] Toners 2 to 38 and C1 to C6 were obtained in the same manner as in the preparation of Toner 1, except that the types and loading amounts of the resin particle dispersions were changed as shown in Table 3. The solid content of each resin particle dispersion was set to 20% by mass.

[0485] In addition, the amorphous polyester resin particle dispersion liquid added later was also changed as shown in Table 3.

[0486] The following parameters are shown for the toners obtained in Examples 1 to 38 and Comparative Examples 1 to 6. The method for measuring the characteristics of the toners is as described above.

[0487] Minimum value of the loss tangent tanδ (min) at 50°C or higher and 80°C or lower in the toner particles

[0488] Loss tangent tanδ(90) at 90°C in toner particles

[0489] The ratio of the total of the structural units derived from an aliphatic dicarboxylic acid represented by the structural formula (A) and the structural units derived from an aliphatic diol represented by the following structural formula (B) to all the structural units constituting the amorphous polyester resin (denoted as "Ratio of Structures A+B")

[0490] The ratio of the structural unit derived from an aliphatic dicarboxylic acid represented by the structural formula (A) in all the structural units derived from carboxylic acid constituting the amorphous polyester resin (denoted as "ratio of structure A")

[0491] ·The content of crystalline resin relative to binder resin

[0492] Glass transition temperature Tg of added cross-linked resin particles

[0493] Amount M1 of one or more metal ions selected from the group consisting of Al, Mg, and Ca in the toner particles

[0494] The ratio of the amount of metal ions M1 to the acid value AV1 of the binder resin AV1 / M1

[0495] [evaluate]

[0496] (Production of Developer)

[0497] 8 parts of each toner obtained in each example and 92 parts of the following carrier were mixed to obtain a developer. The obtained developer was used in the evaluation described below.

[0498] (Carrier Preparation)

[0499] Ferrite particles (average particle size 35 μm): 100 parts

[0500] Toluene: 14 parts

[0501] Styrene / methyl methacrylate copolymer (copolymer ratio 15 / 85): 3 parts

[0502] Carbon black: 0.2 parts

[0503] The above components except the ferrite particles were dispersed in a sand mill to prepare a dispersion, and the dispersion was placed in a vacuum degassing kneader together with the ferrite particles, and dried under reduced pressure while stirring to obtain a carrier.

[0504] (Low-temperature fixability)

[0505] The developer obtained was filled into the developing unit of a color copier Apeos C6570 (manufactured by FUJIFILM Business Innovation Corp.) with the fixing unit removed, and the toner load was adjusted to 9.0 g / cm 2 Colotech 90 paper (manufactured by Xerox Corporation / basis weight 90 gsm) was used as the recording medium. The output image had a size of 50 mm x 50 mm and an image density of 100%.

[0506] The unfixed images were then fixed using a fixing evaluation device, and low-temperature fixing properties were evaluated. A fixing device was used, which had been modified from the fixing unit of a FUJIFILM Business Innovation Corp. Apeos C6570, manufactured by FUJIFILM Business Innovation Corp., to allow for variable fixing temperatures. The fixing temperature was increased in 5°C increments from 120°C to 190°C. The temperature at which image defects caused by offset (a phenomenon in which toner does not sufficiently melt and adheres to the fixing component) ceased to occur was defined as the minimum fixing temperature, and the images were classified as follows.

[0507] A: The minimum fixing temperature is below 145°C

[0508] B: The minimum fixing temperature is more than 145°C and less than 155°C

[0509] C: The minimum fixing temperature is higher than 155°C and lower than 165°C

[0510] D: The minimum fixing temperature exceeds 165°C

[0511] (Contamination of the end of the recording medium)

[0512] Each of the prepared developers was filled in a developing device of a color copier Apeos C6570 (manufactured by FUJIFILM Business Innovation Corp.), which is an apparatus for image evaluation.

[0513] Using an image evaluation device, 50,000 sheets of A3 Business 80 paper were continuously printed with a full-surface halftone image at 50% image density at 10°C and 15% density. The last 1,000 printed sheets were then overlaid, and the reflection density at the edge of the stacked sheets was measured at 20 points using a reflection spectrophotometer (Xrite-939, manufactured by X-Rite, Inc.). 1,000 unprinted sheets were then overlaid, and the density at the edge of the stacked sheets was measured in the same manner. The difference in density before and after printing was used to evaluate edge contamination of the recording medium. The evaluation criteria are as follows.

[0514] A+: The maximum and average values ​​of the 20 points are both less than 0.01

[0515] A: The maximum value of 20 is 0.01 or more and less than 0.02 and the average value is less than 0.01

[0516] B: The maximum value of the 20 points is 0.02 or more and less than 0.04, and the average value is less than 0.02

[0517] C: The maximum value of the 20 points is 0.04 or more and the average value is less than 0.04

[0518] D: The maximum value and average value of the 20 points are both 0.04 or higher

[0519]

[0520]

[0521] [Table 3-1]

[0522]

[0523] [Table 3-2]

[0524]

[0525] [Table 3-3]

[0526]

[0527] From the above results, it is understood that the toner of this embodiment has a better low-temperature fixability than the toner of the comparative example and can suppress contamination of the edge of the recording medium.

[0528] This embodiment includes the following aspects. (1)

[0530] A toner for developing electrostatic images, comprising toner particles containing an amorphous polyester resin as a binder resin and a crystalline resin,

[0531] The toner particles contain an amorphous polyester resin (S) as the amorphous polyester resin, wherein the amorphous polyester resin (S) has at least one of a structural unit derived from an aliphatic dicarboxylic acid represented by the following structural formula (A) and a structural unit derived from an aliphatic diol represented by the following structural formula (B).

[0532] The total proportion of the structural unit derived from an aliphatic dicarboxylic acid represented by the following structural formula (A) and the structural unit derived from an aliphatic diol represented by the following structural formula (B) in all the structural units constituting the amorphous polyester resin is 0.5% or more and 10.0% or less by mole,

[0533] In a dynamic viscoelasticity measurement of the toner particles when the temperature is increased from 30° C. to 120° C., a minimum loss tangent tan δ (min) exists at 50° C. to 80° C., and the minimum loss tangent tan δ (min) is 0.50 to 1.00.

[0534] [Chemical Formula 3]

[0535]

[0536] In structural formulae (A) and (B), nA and nB each independently represent an integer of 2 or more and 12 or less. (2)

[0538] The electrostatic image developing toner according to (1), wherein

[0539] The amorphous polyester resin (S) comprises only the structural unit derived from an aliphatic dicarboxylic acid represented by the structural formula (A) and the structural unit derived from an aliphatic diol represented by the structural formula (B).

[0540] The proportion of the structural unit derived from an aliphatic dicarboxylic acid represented by the structural formula (A) in all the structural units derived from carboxylic acid constituting the amorphous polyester resin is 2.0% or more and 15.0% or less in terms of molar ratio. (3)

[0542] The electrostatic image developing toner according to (2), wherein

[0543] The proportion of the structural unit derived from an aliphatic dicarboxylic acid represented by the structural formula (A) in all the structural units derived from carboxylic acid constituting the amorphous polyester resin is 3.0% or more and 10.0% or less by mole. (4)

[0545] The electrostatic image developing toner according to any one of (1) to (3), wherein

[0546] The minimum value of the loss tangent, tan δ (min), is 0.60 or more and 0.90 or less. (5)

[0548] The electrostatic image developing toner according to any one of (1) to (4), wherein

[0549] The ratio of the minimum value of the loss tangent tanδ(min) to the loss tangent tanδ(90) at a temperature of 90°C, tanδ(90) / tanδ(min), is 2.5 or less. (6)

[0551] The electrostatic image developing toner according to any one of (1) to (5), wherein

[0552] The toner particles include internally added crosslinked resin particles. (7)

[0554] The electrostatic image developing toner according to (6), wherein

[0555] The glass transition temperature Tg of the internally added cross-linked resin particles is 0° C. or higher and 40° C. or lower. (8)

[0557] The electrostatic image developing toner according to any one of (1) to (7), wherein

[0558] The crystalline resin is a crystalline polyester resin,

[0559] The content of the crystalline polyester resin relative to the binder resin is 10% by mass or more and 30% by mass or less. (9)

[0561] The electrostatic image developing toner according to any one of (1) to (8), wherein

[0562] The toner particles contain one or more metal ions selected from the group consisting of Al, Mg, and Ca.

[0563] The ratio of the amount of the metal ion M1 to the acid value AV1 of the binder resin is 1.0×10 3 Above and 4.0×10 3 the following. (10)

[0565] The electrostatic image developing toner according to (9), wherein

[0566] The ratio of the amount of the metal ion M1 to the acid value AV1 of the binder resin is 2.0×10 3 Above and 3.5×10 3 the following. (11)

[0568] An electrostatic image developer comprising the electrostatic image developing toner according to any one of (1) to (10). (12)

[0570] A toner cartridge containing the electrostatic image developing toner described in any one of (1) to (10),

[0571] The image forming apparatus is mounted and removed from the image forming apparatus. (13)

[0573] A process cartridge comprising a developing device that accommodates the electrostatic image developer described in (11) and develops an electrostatic image formed on a surface of an image holding member into a toner image using the electrostatic image developer.

[0574] The process cartridge is attachable to and detachable from the image forming apparatus. (14)

[0576] An image forming apparatus comprising:

[0577] Image holding body;

[0578] a charging device for charging the surface of the image holding member;

[0579] an electrostatic image forming device for forming an electrostatic image on the charged surface of the image holding member;

[0580] a developing device that accommodates the electrostatic image developer described in (11) and develops the electrostatic image formed on the surface of the image holding member into a toner image using the electrostatic image developer;

[0581] a transfer device that transfers the toner image formed on the surface of the image holding member to the surface of a recording medium; and

[0582] The fixing device fixes the toner image transferred onto the surface of the recording medium. (15)

[0584] An image forming method comprising:

[0585] a charging process for charging the surface of the image holding member;

[0586] an electrostatic image forming step of forming an electrostatic image on the charged surface of the image holding member;

[0587] a developing step of developing the electrostatic image formed on the surface of the image holding member into a toner image using the electrostatic image developer described in (11);

[0588] a transfer step of transferring the toner image formed on the surface of the image holding member to the surface of a recording medium; and

[0589] The fixing step fixes the toner image transferred onto the surface of the recording medium.

[0590] The effects of the above method are as follows.

[0591] According to the invention according to (1), there is provided a toner for electrostatic image development as follows: compared to a toner having toner particles containing an amorphous polyester resin as a binder resin and a crystalline resin, in which the toner particles contain an amorphous polyester resin (S) as the amorphous polyester resin, wherein the amorphous polyester resin (S) has at least one of a structural unit derived from an aliphatic dicarboxylic acid represented by the structural formula (A) and a structural unit derived from an aliphatic diol represented by the structural formula (B), When the total molar ratio of the structural units of the carboxylic acid and the structural units derived from the aliphatic diol represented by the structural formula (B) in all the structural units constituting the amorphous polyester resin is less than 0.5% or exceeds 10.0%, or when the minimum value of the loss tangent tanδ(min) existing at 50°C to 80°C in the dynamic viscoelasticity measurement at a temperature rise from 30°C to 120°C in the toner particles is less than 0.50 or exceeds 1.00, the toner has low-temperature fixing ability and can suppress contamination of the edge of the recording medium.

[0592] According to the invention according to (2), there is provided a toner for developing electrostatic images having low-temperature fixing properties and capable of suppressing contamination of the edge of a recording medium, compared to a case where the proportion of the structural unit derived from an aliphatic dicarboxylic acid represented by the structural formula (A) in all the structural units derived from carboxylic acid constituting the amorphous polyester resin is less than 2.0% or exceeds 15.0% by mole.

[0593] According to the invention according to (3), there is provided a toner for electrostatic image development having low-temperature fixing properties and capable of suppressing contamination of the edge of a recording medium, compared to a case where the proportion of the structural unit derived from an aliphatic dicarboxylic acid represented by the structural formula (A) in all the structural units derived from carboxylic acid constituting the amorphous polyester resin is less than 3.0% or exceeds 10.0% by mole.

[0594] According to the invention involved in (4), the following electrostatic image developing toner is provided: compared with the dynamic viscoelasticity measurement when the temperature in the toner particles is increased from 30°C to 120°C, a minimum value of the loss tangent tanδ(min) exists at 50°C or above and 80°C or below, and the minimum value of the loss tangent tanδ(min) is less than 0.60 or exceeds 0.90, the toner has low-temperature fixing properties, and can suppress contamination of the edge of the recording medium.

[0595] According to the invention involved in (5), the following electrostatic image developing toner is provided: compared with the case where the ratio of the loss tangent tanδ(90) / tanδ(min) of the minimum value of the loss tangent tanδ(min) to the loss tangent tanδ(90) at a temperature of 90°C exceeds 2.5, the toner has low-temperature fixing properties and can suppress contamination of the edge of the recording medium.

[0596] According to the invention according to (6), there is provided a toner for developing electrostatic images that has low-temperature fixing properties and can suppress contamination of the edge of a recording medium compared to a case where toner particles do not contain internally added crosslinked resin particles.

[0597] According to the invention described in (7), there is provided a toner for electrostatic image development that has low-temperature fixability compared to a case where the glass transition temperature Tg of the internally added cross-linked resin particles is less than 0°C or exceeds 40°C and can suppress contamination of the edge of a recording medium.

[0598] According to the invention described in (8), there is provided a toner for developing electrostatic images that has low-temperature fixing properties and can suppress contamination of the edge of a recording medium compared to a case where the content of the crystalline polyester resin relative to the binder resin is less than 10% by mass or exceeds 30% by mass.

[0599] According to the invention described in (9), there is provided a toner for developing an electrostatic image in which the ratio AV1 / M1 of the amount of metal ions M1 to the acid value AV1 of the binder resin is less than 1.0×10 3 or more than 4.0×10 3 In the case of the above, it has low-temperature fixing properties and can suppress contamination of the end portions of the recording medium.

[0600] According to the invention of (10), there is provided a toner for developing an electrostatic image in which the ratio AV1 / M1 of the amount of metal ions M1 to the acid value AV1 of the binder resin is less than 2.0×10 3 or more than 3.5×10 3 In the case of the above, it has low-temperature fixing properties and can suppress contamination of the end portions of the recording medium.

[0601] According to the invention of (11), (12), (13), (14) or (15), there is provided an electrostatic image developing agent, a toner cartridge, a process cartridge, an image forming apparatus or an image forming method: compared to a toner particle having an amorphous polyester resin as a binder resin and a crystalline resin, the toner particle contains an amorphous polyester resin (S) as the amorphous polyester resin, the amorphous polyester resin (S) having at least one of a structural unit derived from an aliphatic dicarboxylic acid represented by structural formula (A) and a structural unit derived from an aliphatic diol represented by structural formula (B) In the toner, when the total molar ratio of the structural units derived from aliphatic dicarboxylic acid represented by structural formula (A) and the structural units derived from aliphatic diol represented by structural formula (B) in all the structural units constituting the amorphous polyester resin is less than 0.5% or exceeds 10.0%, or when the minimum value of the loss tangent tanδ (min) existing at 50°C to 80°C in the dynamic viscoelasticity measurement at a temperature of 30°C to 120°C in the toner particles is less than 0.50 or exceeds 1.00, the toner has low-temperature fixing properties and can suppress contamination of the edge of the recording medium.

[0602] The above-described embodiments of the present invention are provided for the purpose of illustration and explanation. In addition, the embodiments of the present invention do not fully and exhaustively include the present invention, and do not limit the present invention to the disclosed embodiments. It is obvious that various modifications and variations are self-evident to those skilled in the art to which the present invention belongs. The present embodiment is selected and described in order to most easily explain the principles of the present invention and its application. Thus, other technical personnel in this field can understand the present invention through various modifications optimized for specific uses of the assumed various embodiments. The scope of the present invention is defined by the above claims and their equivalents.

Claims

1. A toner for developing electrostatic images, comprising toner particles containing an amorphous polyester resin as a binder resin and a crystalline resin, The toner particles contain an amorphous polyester resin (S) as the amorphous polyester resin, wherein the amorphous polyester resin (S) has at least one of a structural unit derived from an aliphatic dicarboxylic acid represented by the following structural formula (A) and a structural unit derived from an aliphatic diol represented by the following structural formula (B). The total proportion of the structural unit derived from an aliphatic dicarboxylic acid represented by the following structural formula (A) and the structural unit derived from an aliphatic diol represented by the following structural formula (B) in all the structural units constituting the amorphous polyester resin is 0.5% or more and 10.0% or less by mole, In a dynamic viscoelasticity measurement of the toner particles when the temperature is increased from 30° C. to 120° C., a minimum loss tangent value tan δ (min) exists at 50° C. to 80° C., and the minimum loss tangent value tan δ (min) is 0.50 to 1.

00. [Chemical Formula 1] In structural formulae (A) and (B), nA and nB each independently represent an integer of 2 or more and 12 or less.

2. The electrostatic image developing toner according to claim 1, wherein The amorphous polyester resin (S) comprises only the structural unit derived from an aliphatic dicarboxylic acid represented by the structural formula (A) and the structural unit derived from an aliphatic diol represented by the structural formula (B). The proportion of the structural unit derived from an aliphatic dicarboxylic acid represented by the structural formula (A) in all the structural units derived from carboxylic acid constituting the amorphous polyester resin is 2.0% or more and 15.0% or less in terms of molar ratio.

3. The electrostatic image developing toner according to claim 2, wherein The proportion of the structural unit derived from an aliphatic dicarboxylic acid represented by the structural formula (A) in all the structural units derived from carboxylic acid constituting the amorphous polyester resin is 3.0% or more and 10.0% or less by mole. 4 . The electrostatic image developing toner according to claim 1 , wherein The minimum value of the loss tangent, tan δ (min), is 0.60 or more and 0.90 or less. 5 . The electrostatic image developing toner according to claim 1 , wherein The ratio of the minimum value of the loss tangent tanδ(min) to the loss tangent tanδ(90) at a temperature of 90°C, tanδ(90) / tanδ(min), is 2.5 or less. 6 . The electrostatic image developing toner according to claim 1 , wherein: The toner particles include internally added crosslinked resin particles.

7. The electrostatic image developing toner according to claim 6, wherein The glass transition temperature Tg of the internally added cross-linked resin particles is 0° C. or higher and 40° C. or lower. 8 . The electrostatic image developing toner according to claim 1 , wherein The crystalline resin is a crystalline polyester resin, The content of the crystalline polyester resin relative to the binder resin is 10% by mass or more and 30% by mass or less. 9 . The electrostatic image developing toner according to claim 1 , wherein The toner particles contain one or more metal ions selected from the group consisting of Al, Mg, and Ca. The ratio of the amount of the metal ion M1 to the acid value AV1 of the binder resin is 1.0×10 3 Above and 4.0×10 3 the following.

10. The electrostatic image developing toner according to claim 9, wherein The ratio of the amount of the metal ion M1 to the acid value AV1 of the binder resin is 2.0×10 3 Above and 3.5×10 3 the following. 11 . An electrostatic image developer comprising the electrostatic image developing toner according to claim 1 .

12. A toner cartridge containing the electrostatic image developing toner according to any one of claims 1 to 10, The image forming apparatus is mounted and removed from the image forming apparatus.

13. A process cartridge comprising a developing device, the developing device housing the electrostatic image developer according to claim 11 and developing an electrostatic image formed on a surface of an image holding member into a toner image using the electrostatic image developer, The process cartridge is attachable to and detachable from the image forming apparatus.

14. An image forming apparatus comprising: Image holding body; a charging device for charging the surface of the image holding member; an electrostatic image forming device for forming an electrostatic image on the charged surface of the image holding member; a developing device that accommodates the electrostatic image developer according to claim 11 and develops the electrostatic image formed on the surface of the image holding member into a toner image using the electrostatic image developer; a transfer device for transferring the toner image formed on the surface of the image holding member to the surface of a recording medium; and The fixing device fixes the toner image transferred onto the surface of the recording medium.

15. An image forming method comprising: a charging process for charging the surface of the image holding member; an electrostatic image forming step of forming an electrostatic image on the charged surface of the image holding member; a developing step of developing the electrostatic image formed on the surface of the image holding member into a toner image using the electrostatic image developer according to claim 11; a transfer step of transferring the toner image formed on the surface of the image holding member to the surface of a recording medium; and The fixing step fixes the toner image transferred onto the surface of the recording medium.

Images