Toner for developing electrostatic images, electrostatic image developer, toner cartridge, process cartridge, image forming apparatus, and image forming method

Abstract

To provide a toner for electrostatic charge image development that reduces the degree of uneven brightness of an image when an image with a large placement amount of the toner is formed.SOLUTION: A toner has toner particles in which at least two domains of a crystalline resin satisfy the following (A), the following (B1) or (B2), the following (C), and the following (D). (A) The aspect ratio of the domains of the crystalline resin is 5 or more and 40 or less. (B1) The major axis length of the domains of the crystalline resin is 0.5 μm or more and 1.5 μm or less. (B2) The ratio of the major axis length of the domains of the crystalline resin to the maximum diameter of the toner particle is 10% or more and 30% or less. (C) The angle formed by an extended line of the major axis of the domains of the crystalline resin and a tangent line at a contact where the extended line is in contact with a surface of the toner particle is 60 degrees or more and 90 degrees or less. (D) The intersection angle of the extended lines of the major axes in the two domains of the crystalline resin is 45 degrees or more and 90 degrees of less.SELECTED DRAWING: Figure 3

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 technology]

[0002] Methods for visualizing image information, such as electrophotography, are currently used in a variety of fields. In electrophotography, an electrostatic image is formed as image information on the surface of an image carrier by charging and forming an electrostatic image. Then, a toner image is formed on the surface of the image carrier using a developer containing toner. This toner image is then transferred to a recording medium, and the toner image is then fixed to the recording medium. Through these steps, the image information is visualized as an image.

[0003] For example, Patent Document 1 discloses "a toner including a plurality of toner particles each having a toner core and a shell layer covering the surface of the toner core, wherein the toner core contains a melt-kneaded mixture of an amorphous resin and a crystalline resin, the shell layer contains a thermosetting resin, the melt-kneaded mixture contains a plurality of crystalline resin domains, and the proportion of domains that satisfy the conditions of a minor axis diameter of 50 nm or more and 200 nm or less and an aspect ratio of 4.0 or more and 20.0 or less is 80% or more by number."

[0004] Furthermore, Patent Document 2 discloses "a toner having toner particles containing an amorphous polyester resin, a crystalline polyester resin, and a wax, wherein in a cross section of the toner observed with a transmission electron microscope (TEM), domains of the wax and crystals of the crystalline polyester resin are present, the area of ​​the cross section of the toner occupied by the wax domains is 0.5% to 8.0% and the area occupied by the crystalline polyester resin crystals is 0.5% to 8.0%, the number average diameter (Dw) of the wax domains is 60 nm to 240 nm, the aspect ratio of the crystalline polyester resin crystals is 5.0 to 25.0, and the number average diameter (Dc) of the major axis length of the crystalline polyester resin crystals is 0.8 to 2.0 times the number average diameter (Dw) of the wax domains." [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-40024 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-003990 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a toner for developing electrostatic images, which has toner particles containing an amorphous resin and a crystalline resin, and which, when a cross section of the toner particle is observed, reduces the degree of uneven gloss in an image that occurs when an image with a large toner coverage is formed, compared to a case in which at least two crystalline resin domains have only toner particles that do not satisfy the following conditions (A), (B1), (C), and (D), or a case in which only toner particles do not satisfy the following conditions (A), (B2), (C), and (D): [Means for solving the problem]

[0007] Means for solving the above problems include the following aspects. <1> A toner for developing electrostatic images, comprising toner particles (hereinafter also referred to as first toner particles) that contain an amorphous resin and a crystalline resin, and in which, when a cross section of the toner particle is observed, at least two domains of the crystalline resin satisfy the following conditions (A), (B1), (C), and (D): Condition (A): The aspect ratio of the domain of the crystalline resin is 5 or more and 40 or less. Condition (B1): The length of the major axis of the domain of the crystalline resin is 0.5 μm or more and 1.5 μm or less. Condition (C): The angle formed by the extension of the long axis of the domain of the crystalline resin and the tangent at the point where the extension comes into contact with the surface of the toner particle is 60 degrees or more and 90 degrees or less. Condition (D): The crossing angle between the extensions of the long axes of the two domains of the crystalline resin is 45 degrees or more and 90 degrees or less. <2> A toner for developing electrostatic images, comprising toner particles (hereinafter also referred to as second toner particles) that contain an amorphous resin and a crystalline resin, and in which, when a cross section of the toner particle is observed, at least two domains of the crystalline resin satisfy the following conditions (A), (B2), (C), and (D): Condition (A): The aspect ratio of the domain of the crystalline resin is 5 or more and 40 or less. Condition (B2): In at least one of the two domains of the crystalline resin, the ratio of the major axis length to the maximum diameter of the toner particle is 10% or more and 30% or less. Condition (C): The angle formed by the extension of the long axis of the domain of the crystalline resin and the tangent at the point where the extension comes into contact with the surface of the toner particle is 60 degrees or more and 90 degrees or less. Condition (D): The crossing angle between the extensions of the long axes of the two domains of the crystalline resin is 45 degrees or more and 90 degrees or less. <3> The toner particles contain a release agent, and when a cross section of the toner particles is observed, a domain of the release agent is present at a depth of 50 nm or more from the surface of the toner particles. <1> or <2> 2. The toner for developing electrostatic images according to claim 1. <4> The release agent is an ester wax. <3> 2. The toner for developing electrostatic images according to claim 1. <5> The content of the toner particles is 40% by number or more of the total toner particles. <1> ~ <4> 10. The toner for developing electrostatic images according to claim 9. <6> The content of the toner particles is 70% or more by number of the total toner particles. <5> 2. The toner for developing electrostatic images according to claim 1. <7> <1> ~ <6> 10. An electrostatic image developer comprising the toner for developing electrostatic images according to any one of claims 1 to 9. <8> <1> ~ <6> The toner for developing electrostatic images according to any one of the above items is contained, A toner cartridge that is detachably attached to an image forming device. <9> <7> and a developing means for developing an electrostatic image formed on the surface of an image carrier into a toner image by using the electrostatic image developer, A process cartridge is detachably mounted in an image forming apparatus. <10> an image carrier; a charging means for charging the surface of the image carrier; an electrostatic image forming means for forming an electrostatic image on the charged surface of the image carrier; <7> a developing means for developing the electrostatic image formed on the surface of the image carrier into a toner image by using the electrostatic image developer; a transfer means for transferring the toner image formed on the surface of the image carrier to the surface of a recording medium; a fixing means for fixing the toner image transferred onto the surface of the recording medium; An image forming apparatus comprising: <11> a charging step of charging the surface of the image carrier; an electrostatic image forming step of forming an electrostatic image on the charged surface of the image carrier; <7> a developing step of developing the electrostatic image formed on the surface of the image carrier as a toner image using the electrostatic image developer according to claim 1; a transfer step of transferring the toner image formed on the surface of the image carrier to the surface of a recording medium; a fixing step of fixing the toner image transferred onto the surface of the recording medium; An image forming method comprising the steps of: [Effects of the Invention]

[0008] <1> According to the invention, there is provided a toner for developing electrostatic images that has toner particles containing an amorphous resin and a crystalline resin, and that, when a cross section of the toner particle is observed, at least two crystalline resin domains suppress the degree of uneven gloss in an image that occurs when an image with a large toner loading is formed, compared to a case in which the toner has only toner particles that do not satisfy the above conditions (A), (B1), (C), and (D).

[0009] <2> According to the invention, there is provided a toner for developing electrostatic images, which has toner particles containing an amorphous resin and a crystalline resin, and when a cross section of the toner particle is observed, at least two crystalline resin domains suppress the degree of uneven gloss in an image that occurs when an image with a large toner loading is formed, compared to a case in which the toner has only toner particles that do not satisfy the above conditions (A), (B2), (C), and (D). <3> According to the invention, there is provided a toner for developing electrostatic images that suppresses the degree of uneven gloss of an image that occurs when an image with a large toner loading is formed, compared to when the domains of the release agent are present at a depth of less than 50 nm from the surface of the toner particle. <4> According to the present invention, there is provided a toner for developing electrostatic images that suppresses the degree of uneven gloss in an image that occurs when an image with a large toner loading is formed, compared to when the release agent is a polyethylene wax or a paraffin wax.

[0010] <5> , or <6> According to the invention, a toner for developing electrostatic images is provided that suppresses the degree of uneven gloss in an image that occurs when an image with a high toner loading is formed, compared to when the content of first toner particles and second toner particles is less than 40% by number or less than 70% by number.

[0011] <7> , <8> , <9> , <10> or <11> According to the invention, in a toner for developing electrostatic images having toner particles containing an amorphous resin and a crystalline resin, when a cross section of the toner particle is observed, at least two crystalline resin domains have only toner particles that do not satisfy the above conditions (A), (B1), (C), and (D), and compared to a case where a toner for developing electrostatic images having only toner particles that do not satisfy the above conditions (A), (B2), (C), and (D) is used, an electrostatic image developer, toner cartridge, process cartridge, image forming apparatus, or image forming method is provided that suppresses the degree of uneven gloss in an image that occurs when an image with a large toner loading is formed. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram illustrating an example of a process cartridge according to the present exemplary embodiment. [Figure 3] 1 is a schematic diagram illustrating a cross section of a toner particle in a toner for developing an electrostatic image according to an exemplary embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, an embodiment of the present invention will be described in detail. In addition, in numerical ranges described in stages, the upper limit or lower limit value described in a certain numerical range may be replaced with the upper limit or lower limit value of another numerical range described in stages. Furthermore, in a numerical range, the upper limit or lower limit value described in a certain numerical range may be replaced with a value shown in the examples. When a plurality of substances corresponding to each component are present in the composition, the amount of each component in the composition means the total amount of the plurality of substances present in the composition, unless otherwise specified. The term "process" includes not only an independent process but also a process that cannot be clearly distinguished from other processes as long as the intended purpose of the process is achieved.

[0014] <Toner for developing electrostatic images> (First embodiment) The toner for developing electrostatic images according to the first embodiment (hereinafter referred to as "toner") is The toner particles include an amorphous resin and a crystalline resin, and when a cross section of the toner particle is observed, at least two crystalline resin domains satisfy the following conditions (A), (B1), (C), and (D): Condition (A): The aspect ratio of the domain of the crystalline resin is 5 or more and 40 or less. Condition (B1): The length of the major axis of the domain of the crystalline resin is 0.5 μm or more and 1.5 μm or less. Condition (C): The angle formed by the extension of the long axis of the crystalline resin domain and the tangent at the point where the extension comes into contact with the surface of the toner particle is 60 degrees or more and 90 degrees or less. Condition (D): The crossing angle between the extensions of the long axes of the two crystalline resin domains is 45 degrees or more and 90 degrees or less.

[0015] The toner according to the first embodiment, due to the above-described configuration, suppresses the degree of uneven glossiness of an image that occurs when an image with a large amount of toner is formed. The reason for this is presumed to be as follows.

[0016] A three-dimensional image called a thick print is sometimes formed to impart a three-dimensional texture to an image. Thick prints are typically performed by printing multiple times, but the more times the prints are performed, the longer the time required and the more likely the prints are to become misaligned. Therefore, there is a need for a method to reduce the number of prints by increasing the amount of toner applied. In this context, a technology is known in which crystalline resin domains in toner particles are elliptical, allowing the amorphous resin and crystalline resin to be compatible with each other when the toner image is fixed, making it easier for the toner particles to melt (see, for example, Patent Document 1). However, in the toner of this technology, the domains of the crystalline resin in the toner particles all face in the same direction. This can lead to unevenness in the presence of the crystalline resin on the toner particle surface. This can lead to problems when the toner load is increased (for example, when the toner load is 10.0 g / m). 2 When the temperature is increased above 100°C, the heat is not uniformly transferred to the entire toner particle, which can cause uneven melting of the toner particles when fixing the toner image, resulting in uneven gloss of the image.

[0017] In contrast, the first toner particles that satisfy the above conditions allow heat to be transmitted more uniformly throughout the toner particles, and uneven melting of the toner particles is less likely to occur when the toner image is fixed. Here, the first toner particles satisfying the above conditions means that the first toner particles are elliptical or needle-shaped with a large aspect ratio, and two crystalline resin domains with long major axes extend from the surface side of the toner particles toward the inside and are arranged in an intersecting manner (see Figure 3). When heat is applied to the first toner particles during fixing of a toner image having the first toner particles that satisfy the above conditions, the ellipsoidal or needle-shaped crystalline resin melts, facilitating rapid transfer of heat from the surface to the interior of the first toner particles, thereby transferring heat almost uniformly throughout the entire interior of the toner particles, and making it easier for the entire interior of the toner particles to melt in an almost uniform manner.

[0018] Therefore, even when the toner amount is increased (for example, when the toner amount is increased to 10.0 g / m 2Even when the amount of the toner particles is increased to above 1000 ppm, uneven melting of the toner particles is unlikely to occur when the toner image is fixed.

[0019] From the above, it is presumed that the toner according to the first embodiment suppresses the degree of uneven glossiness in an image that occurs when an image with a large amount of toner is formed.

[0020] Second Embodiment The toner for developing electrostatic images according to the second embodiment (hereinafter referred to as "toner") is A toner for developing electrostatic images, comprising an amorphous resin and a crystalline resin, and having second toner particles in which, when a cross section of the toner particle is observed, at least two domains of the crystalline resin satisfy the following conditions (A), (B2), (C), and (D): Condition (A): The aspect ratio of the domain of the crystalline resin is 5 or more and 40 or less. Condition (B2): In at least one of the two domains of the crystalline resin, the ratio of the major axis length to the maximum diameter of the toner particle is 10% or more and 30% or less. Condition (C): The angle formed by the extension of the long axis of the crystalline resin domain and the tangent at the point where the extension comes into contact with the surface of the toner particle is 60 degrees or more and 90 degrees or less. Condition (D): The crossing angle between the extensions of the long axes of the two crystalline resin domains is 45 degrees or more and 90 degrees or less.

[0021] The toner according to the second embodiment, due to the above-described configuration, suppresses the degree of uneven glossiness of an image that occurs when an image with a large amount of toner is formed. The reason for this is presumed to be as follows.

[0022] The second toner particles that satisfy the above conditions allow heat to be transmitted more uniformly throughout the toner particles, and uneven melting of the toner particles is less likely to occur when the toner image is fixed. Here, the second toner particles satisfying the above conditions means that, similar to the first toner particles in the first embodiment, the second toner particles have an elliptical or needle shape with a large aspect ratio, and two crystalline resin domains with long major axes extend from the surface side of the toner particles toward the inside and are arranged in an intersecting manner (see Figure 3). Therefore, similarly to the first toner particles in the first embodiment, even when the toner amount is increased (for example, when the toner amount is increased to 10.0 g / m 2 Even when the amount of the toner particles is increased to 1000 ppm, uneven melting of the toner particles is less likely to occur when the toner image is fixed.

[0023] When heat is applied to the second toner particles during fixing of a toner image having the second toner particles that satisfy the above conditions, the ellipsoidal or needle-shaped crystalline resin melts, facilitating rapid heat transfer from the surface to the interior of the second toner particles, thereby allowing heat to be transferred almost uniformly throughout the toner particles, and making it easier for the entire toner particles to melt in an almost uniform manner.

[0024] From the above, it is presumed that the toner according to the second embodiment suppresses the degree of uneven glossiness in an image that occurs when an image with a large amount of toner is formed.

[0025] Here, the symbols shown in FIG. TN: Toner particles Amo: Amorphous resin Cry: crystalline resin L cry : Long axis length of the domain of the crystalline resin L T : Maximum diameter of toner particles θ A : The angle between the extension of the long axis of the crystalline resin domain and the tangent at the point where the extension touches the surface of the toner particle θ B : The crossing angle between the extension lines of the long axes of two crystalline resin domains Shows.

[0026] Hereinafter, a toner corresponding to both the toner according to the first and second embodiments (hereinafter also referred to as "toner according to the present embodiment") will be described in detail. However, an example of the toner of the present invention may be a toner corresponding to either the toner according to the first or second embodiments. Note that the first toner particles and the second toner particles will also be referred to as toner particles.

[0027] The toner according to the exemplary embodiment includes toner particles, and may include an external additive.

[0028] (toner particles) The toner particles contain an amorphous resin and a crystalline resin as binder resins, and may also contain a colorant, a release agent, and other additives.

[0029] - Domain morphology of crystalline resin in toner particles - When a cross section of a toner particle is observed, at least two crystalline resin domains (preferably at least three crystalline resin domains) satisfy conditions (A), (B1), (B2), (C), and (D), provided that the at least two crystalline resin domains only need to satisfy at least one of conditions (B1) and (B2).

[0030] From the viewpoint of suppressing uneven glossiness of an image, the toner particles satisfying each of the conditions preferably account for 40% or more by number of all toner particles, more preferably 70% or more by number, even more preferably 80% or more by number, and particularly preferably 90% or more by number. Ideally, the proportion of toner particles satisfying each of the above conditions is 100% by number. The more toner particles that satisfy the above conditions, the easier it is for the toner particles as a whole to melt in a nearly uniform state, and the easier it is to suppress uneven gloss in the image.

[0031] Similarly to the above, from the viewpoint of suppressing the degree of gloss unevenness in an image, the proportion of toner particles that satisfy the preferred ranges of the conditions described below is preferably 40% by number or more, more preferably 70% by number or more, even more preferably 80% by number or more, and particularly preferably 90% by number or more, relative to all toner particles. Ideally, the proportion of toner particles that satisfy each of the above conditions is 100% by number.

[0032] Each condition will be explained below.

[0033] Condition (A) The aspect ratio of the domain of the crystalline resin is 5 or more and 40 or less. From the viewpoint of suppressing uneven glossiness of an image, the aspect ratio of the domain of the crystalline resin is preferably 10 or more and 40 or less. Here, the aspect ratio of the domain of the crystalline resin means the ratio of the major axis length to the minor axis length (major axis length / minor axis length) in the domain of the crystalline resin. The long axis length of the domain of the crystalline resin means the maximum length of the domain of the crystalline resin. The minor axis length of the domain of the crystalline resin means the maximum length among the lengths in the direction perpendicular to the extension line of the major axis length of the domain of the crystalline resin.

[0034] ·Conditions (B1) The long axis length of the domain of the crystalline resin (L in Figure 3) cry The particle size is between 0.5 μm and 1.5 μm. From the viewpoint of suppressing uneven glossiness of an image, the major axis length of the domain of the crystalline resin is preferably 0.8 μm or more and 1.5 μm or less.

[0035] ·Conditions (B2) In at least one of the two domains of the crystalline resin, the major axis length (L in FIG. 3) relative to the maximum diameter (Lt in FIG. 3) of the toner particle is cry The proportion of those who are not eligible for the 2016 FIFO (see reference) is between 10% and 30%. From the viewpoint of suppressing uneven glossiness of an image, the ratio of the major axis length of the crystalline resin domain to the maximum diameter of the toner particle is preferably 13% or more and 30% or less, and more preferably 17% or more and 30% or less. The maximum diameter of a toner particle means the maximum length of a straight line drawn between any two points on the contour line of the cross section of a toner particle (so-called major axis).

[0036] ·Condition (C) The angle (θ in Figure 3) between the extension of the long axis of the crystalline resin domain and the tangent at the point where the extension touches the surface of the toner particle (i.e., the outer edge of the toner particle) A (see reference) is between 60 and 90 degrees. From the viewpoint of suppressing uneven glossiness of an image, the angle formed by the extension of the long axis of the crystalline resin domain and the tangent at the point where the extension comes into contact with the surface of the toner particle is preferably 75 degrees or more and 90 degrees or less.

[0037] Condition (D) The crossing angle between the extension lines of the long axes of the two crystalline resin domains (θ B (see reference) is between 45 degrees and 90 degrees. From the viewpoint of suppressing uneven gloss of the image, the crossing angle of the extension lines of the long axes of the two crystalline resin domains (θ B The angle (see reference) is preferably between 60 degrees and 90 degrees. Here, even if there are three or more crystalline resin domains that satisfy conditions (A), (B1), and (C) in the toner particles, or three or more crystalline resin domains that satisfy conditions (A), (B2), and (C), any two of the crystalline resin domains may satisfy condition (D).

[0038] -Method for observing the cross section of a toner particle The method for observing the cross section of a toner particle to determine whether the toner particle satisfies the conditions (A), (B1), (B2), (C) and (D) is as follows. Toner particles (or toner particles with external additives attached) are mixed and embedded in epoxy resin, and the epoxy resin is solidified. The solidified material is cut using an ultramicrotome (Leica Ultracut UCT) to prepare thin section samples with thicknesses of 80 nm to 130 nm. The obtained thin section samples are then stained with ruthenium tetroxide for 3 hours in a desiccator at 30°C. An ultra-high-resolution field emission scanning electron microscope (FE-SEM, Hitachi High-Technologies Corporation S-4800) is then used to obtain STEM observation images (accelerating voltage: 30 kV, magnification: 20,000x) in transmission image mode of the stained thin section samples. The crystalline polyester resin and release agent are identified from the contrast and shape of the toner particles. In the SEM image, binder resins other than the release agent have many double bonds and are stained with ruthenium tetroxide, so the release agent portion can be distinguished from the resin portion other than the release agent. That is, the release agent is the domain that is dyed lightest with ruthenium, followed by the crystalline resin (e.g., crystalline polyester resin). The amorphous resin (for example, amorphous polyester resin) is dyed the darkest. By adjusting the contrast, the release agent can be observed as a white domain, the amorphous resin as a black domain, and the crystalline resin as a light gray domain.

[0039] Then, the area of ​​the ruthenium-dyed crystalline resin is subjected to image analysis to determine whether the toner particles satisfy the conditions (A), (B1), (B2), (C) and (D). In addition, when determining the proportion of toner particles that satisfy each of the above conditions, 100 toner particles are observed, and the proportion of toner particles that satisfy each of the above conditions is calculated.

[0040] Note that, since SEM images contain toner particle cross sections of various sizes, toner particle cross sections whose diameter is 85% or more of the volume average particle diameter of the toner particles are selected as the toner particles to be observed. Here, the diameter of the toner particle cross section refers to the longest length (so-called major axis) of a line drawn between any two points on the outline of the toner particle cross section.

[0041] -Binder resin- The binder resin may be an amorphous resin or a crystalline resin. However, the mass ratio of the amorphous resin to the crystalline resin (crystalline resin / amorphous resin) is preferably 3 / 97 or more and 50 / 50 or less, and more preferably 7 / 93 or more and 30 / 70 or less.

[0042] Here, the term "amorphous resin" refers to a resin that, in thermal analysis measurement using differential scanning calorimetry (DSC), does not show a clear endothermic peak but only a stepwise endothermic change, is solid at room temperature, and becomes thermoplastic at a temperature equal to or higher than the glass transition temperature. On the other hand, a crystalline resin is one that shows a clear endothermic peak rather than a stepwise change in endothermic amount in differential scanning calorimetry (DSC). Specifically, for example, a crystalline resin means a resin whose half-width of the endothermic peak when measured at a heating rate of 10°C / min is within 10°C, and an amorphous resin means a resin whose half-width exceeds 10°C or a resin in which no clear endothermic peak is observed.

[0043] The amorphous resin will be described. Examples of amorphous resins include known amorphous resins such as amorphous polyester resins, amorphous vinyl resins (e.g., styrene-acrylic resins), epoxy resins, polycarbonate resins, polyurethane resins, etc. Among these, amorphous polyester resins and amorphous vinyl resins (particularly styrene-acrylic resins) are preferred, and amorphous polyester resins are more preferred. In addition, it is also a preferred embodiment to use an amorphous polyester resin and a styrene-acrylic resin in combination as the amorphous resin.

[0044] Examples of the amorphous polyester resin include a condensation polymer of a polycarboxylic acid and a polyhydric alcohol. Note that, as the amorphous polyester resin, a commercially available product or a synthesized product may be used.

[0045] Examples of polycarboxylic acids include aliphatic dicarboxylic acids (such as oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, alkenylsuccinic acid, adipic acid, and sebacic acid), alicyclic dicarboxylic acids (such as cyclohexanedicarboxylic acid), aromatic dicarboxylic acids (such as terephthalic acid, isophthalic acid, phthalic acid, and naphthalenedicarboxylic acid), anhydrides thereof, and lower alkyl esters thereof (e.g., having 1 to 5 carbon atoms). Among these, aromatic dicarboxylic acids are preferred as polycarboxylic acids. The polycarboxylic acid may be a trivalent or higher carboxylic acid having a crosslinked or branched structure in combination with a dicarboxylic acid. Examples of the trivalent or higher carboxylic acid include trimellitic acid, pyromellitic acid, anhydrides thereof, and lower alkyl esters thereof (e.g., having 1 to 5 carbon atoms). The polycarboxylic acids may be used alone or in combination of two or more.

[0046] Examples of polyhydric alcohols include aliphatic diols (e.g., ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, etc.), alicyclic diols (e.g., cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, etc.), and aromatic diols (e.g., ethylene oxide adducts of bisphenol A, propylene oxide adducts of bisphenol A, etc.). Among these, preferred polyhydric alcohols are aromatic diols and alicyclic diols, and more preferred are aromatic diols. As the polyhydric alcohol, a trihydric or higher polyhydric alcohol having a crosslinked or branched structure may be used in combination with the diol. Examples of trihydric or higher polyhydric alcohols include glycerin, trimethylolpropane, and pentaerythritol. The polyhydric alcohols may be used alone or in combination of two or more.

[0047] The amorphous polyester resin can be obtained by a known manufacturing method, for example, by carrying out the reaction at a polymerization temperature of 180°C or higher and 230°C or lower, reducing the pressure in the reaction system as necessary, and removing water and alcohol generated during the condensation. If the raw material monomer is not soluble or compatible at the reaction temperature, a high-boiling solvent may be added as a solubilizer to dissolve it. In this case, the polycondensation reaction is carried out while distilling off the solubilizer. If a monomer with poor compatibility is present, it is advisable to first condense the poorly compatible monomer with the acid or alcohol to be polycondensed, and then polycondense the monomer with the main component.

[0048] Here, examples of the amorphous polyester resin include not only the unmodified amorphous polyester resin described above, but also modified amorphous polyester resins. Modified amorphous polyester resins include amorphous polyester resins containing bonding groups other than ester bonds, and amorphous polyester resins in which a resin component different from the amorphous polyester resin component is bonded by a covalent bond, an ionic bond, or the like. Examples of modified amorphous polyester resins include amorphous polyester resins in which a functional group such as an isocyanate group reactive with an acid group or a hydroxyl group is introduced at the terminal, and resins in which the terminals are modified by reacting the resin with an active hydrogen compound.

[0049] Styrene-acrylic resins are copolymers obtained by copolymerizing at least a styrene-based monomer (a monomer having a styrene skeleton) and a (meth)acrylic-based monomer (a monomer having a (meth)acrylic group, preferably a monomer having a (meth)acryloxy group). The styrene-acrylic resins include, for example, copolymers of a styrene monomer and a (meth)acrylic acid ester monomer. The acrylic resin portion of the styrene-acrylic resin is a partial structure formed by polymerizing either an acrylic monomer or a methacrylic monomer, or both. Furthermore, the term "(meth)acrylic" includes both "acrylic" and "methacrylic."

[0050] Specific examples of styrene-based monomers include styrene, alkyl-substituted styrenes (e.g., α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, etc.), halogen-substituted styrenes (e.g., 2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, etc.), vinylnaphthalene, etc. The styrene-based monomers may be used alone or in combination of two or more. Of these, styrene is preferred as the styrene-based monomer in terms of ease of reaction, ease of reaction control, and availability.

[0051] Specific examples of (meth)acrylic monomers include (meth)acrylic acid and (meth)acrylic acid esters. Examples of (meth)acrylic acid esters include (meth)acrylic acid alkyl esters (e.g., methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, n-lauryl (meth)acrylate, n-tetradecyl (meth)acrylate, n-hexadecyl (meth)acrylate, n-octadecyl (meth)acrylate, isopropyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, isopentyl (meth)acrylate, amyl (meth)acrylate, and (meth) Examples of the (meth)acrylic acid monomer include neopentyl acrylate, isohexyl (meth)acrylate, isoheptyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, etc.), aryl (meth)acrylate esters (e.g., phenyl (meth)acrylate, biphenyl (meth)acrylate, diphenylethyl (meth)acrylate, t-butylphenyl (meth)acrylate, terphenyl (meth)acrylate, etc.), dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, methoxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, β-carboxyethyl (meth)acrylate, and (meth)acrylamide. The (meth)acrylic acid monomers may be used alone or in combination of two or more. Among these (meth)acrylic esters among the (meth)acrylic monomers, (meth)acrylic acid esters having an alkyl group with 2 to 14 carbon atoms (preferably 2 to 10 carbon atoms, more preferably 3 to 8 carbon atoms) are preferred from the viewpoint of fixability. Of these, n-butyl (meth)acrylate is preferred, and n-butyl acrylate is particularly preferred.

[0052] The copolymerization ratio of the styrene-based monomer to the (meth)acrylic monomer (based on mass, styrene-based monomer / (meth)acrylic monomer) is not particularly limited, but is preferably 85 / 15 to 70 / 30.

[0053] The styrene-acrylic resin may have a crosslinked structure. Preferred examples of the styrene-acrylic resin having a crosslinked structure include copolymers of at least a styrene-based monomer, a (meth)acrylic acid-based monomer, and a crosslinkable monomer.

[0054] Examples of the crosslinkable monomer include bifunctional or higher functional crosslinking agents. Examples of bifunctional crosslinking agents include divinylbenzene, divinylnaphthalene, di(meth)acrylate compounds (e.g., diethylene glycol di(meth)acrylate, methylene bis(meth)acrylamide, decanediol diacrylate, glycidyl (meth)acrylate, etc.), polyester-type di(meth)acrylate, 2-([1'-methylpropylideneamino]carboxyamino)ethyl methacrylate, etc. Examples of polyfunctional crosslinking agents include tri(meth)acrylate compounds (e.g., pentaerythritol tri(meth)acrylate, trimethylolethane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, etc.), tetra(meth)acrylate compounds (e.g., pentaerythritol tetra(meth)acrylate, oligoester (meth)acrylate, etc.), 2,2-bis(4-methacryloxy, polyethoxyphenyl)propane, diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, triallyl trimellitate, diallyl chlorendate, etc. Among these, as the crosslinkable monomer, from the viewpoint of suppressing the occurrence of a decrease in image density and the occurrence of image density unevenness, and also from the viewpoint of fixability, a bifunctional or higher (meth)acrylate compound is preferred, a bifunctional (meth)acrylate compound is more preferred, a bifunctional (meth)acrylate compound having an alkylene group with 6 to 20 carbon atoms is even more preferred, and a bifunctional (meth)acrylate compound having a linear alkylene group with 6 to 20 carbon atoms is particularly preferred.

[0055] The copolymerization ratio of the crosslinkable monomer to the total monomers (based on mass, crosslinkable monomer / total monomers) is not particularly limited, but is preferably 2 / 1,000 to 20 / 1,000.

[0056] The method for producing the styrene-acrylic resin is not particularly limited, and various polymerization methods (e.g., solution polymerization, precipitation polymerization, suspension polymerization, bulk polymerization, emulsion polymerization, etc.) are applied. In addition, the polymerization reaction is carried out by a known operation (e.g., batchwise, semi-continuous, continuous, etc.).

[0057] The characteristics of the amorphous resin will be explained. The glass transition temperature (Tg) of the amorphous resin is preferably 50°C or higher and 80°C or lower, and more preferably 50°C or higher and 65°C or lower. The glass transition temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC), more specifically, from the "extrapolated glass transition onset temperature" described in JIS K 7121-1987 "Method for measuring transition temperatures of plastics."

[0058] The weight average molecular weight (Mw) of the amorphous resin is preferably 5,000 or more and 1,000,000 or less, and more preferably 7,000 or more and 500,000 or less. The number average molecular weight (Mn) of the amorphous resin is preferably 2,000 or more and 100,000 or less. The molecular weight distribution Mw / Mn of the amorphous resin is preferably 1.5 or more and 100 or less, and more preferably 2 or more and 60 or less. The weight-average molecular weight and number-average molecular weight are measured by gel permeation chromatography (GPC). Molecular weight measurements by GPC are performed using a Tosoh GPC HLC-8120GPC measuring device and a Tosoh TSKgel SuperHM-M (15 cm) column in THF solvent. The weight-average molecular weight and number-average molecular weight are calculated from the measurement results using a molecular weight calibration curve prepared with monodisperse polystyrene standard samples.

[0059] Here, as the amorphous resin, a hybrid resin having a polyester resin segment and a styrene-acrylic copolymer segment (hereinafter also simply referred to as a "hybrid resin" or a "styrene-acrylic modified polyester resin") may be used.

[0060] The polyester resin segment of the hybrid resin is preferably, for example, an amorphous polyester resin segment, and the hybrid resin has a polyester resin segment, which makes it possible to obtain a toner having excellent low-temperature fixing properties. The amorphous polyester resin constituting the amorphous polyester resin segment is as described above.

[0061] On the other hand, the styrene-acrylic copolymer segment is a copolymer segment of a styrene-based compound and a (meth)acrylic compound.

[0062] Examples of styrene compounds include substituted or unsubstituted styrene, and examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a halogen atom, an alkoxy group having 1 to 5 carbon atoms, a sulfonic acid group, or a salt thereof. Examples of the styrene-based compound include styrenes such as styrene, methylstyrene, α-methylstyrene, β-methylstyrene, tert-butylstyrene, chlorostyrene, chloromethylstyrene, methoxystyrene, styrenesulfonic acid, and salts thereof. Of these, styrene is preferred. From the viewpoint of suppressing the degree of gloss unevenness, the amount of the styrene-based compound, preferably styrene, in the raw material monomers of the styrene-acrylic copolymer segment is preferably 50% by mass or more and 95% by mass or less, more preferably 55% by mass or more and 90% by mass or less, and particularly preferably 60% by mass or more and 85% by mass or less. Furthermore, from the viewpoint of suppressing the degree of gloss unevenness, the content of the styrene-based compound, preferably the monomer unit derived from styrene (also referred to as "monomer unit formed by styrene"), is preferably from 50% by mass to 95% by mass, more preferably from 55% by mass to 90% by mass, and particularly preferably from 60% by mass to 85% by mass, relative to the total mass of the styrene-acrylic copolymer segment. Furthermore, from the viewpoint of suppressing the degree of gloss unevenness, the content of styrene-derived structural units in the hybrid resin is preferably from 1% by mass to 50% by mass, more preferably from 3% by mass to 40% by mass, even more preferably from 5% by mass to 35% by mass, and particularly preferably from 8% by mass to 30% by mass, relative to the total mass of the hybrid resin.

[0063] Preferred (meth)acrylic compounds used to form the styrene-acrylic copolymer segment include (meth)acrylate compounds, (meth)acrylamide compounds, (meth)acrylic acid, and (meth)acrylonitrile, more preferred are (meth)acrylate compounds, and particularly preferred are alkyl esters of (meth)acrylic acid. In the case of alkyl esters of (meth)acrylic acid, the hydrocarbon group is the alcohol residue of the ester. Examples of alkyl esters of (meth)acrylic acid include (iso)propyl (meth)acrylate, (iso)butyl (meth)acrylate, (iso)hexyl (meth)acrylate, cyclohexyl (meth)acrylate, (iso)octyl (meth)acrylate (hereinafter also referred to as 2-ethylhexyl (meth)acrylate), (iso)decyl (meth)acrylate, (iso)dodecyl (meth)acrylate (hereinafter also referred to as (iso)lauryl (meth)acrylate), (iso)palmityl (meth)acrylate, (iso)stearyl (meth)acrylate, and (iso)behenyl (meth)acrylate. Among these, 2-ethylhexyl (meth)acrylate, (iso)decyl (meth)acrylate, (iso)dodecyl (meth)acrylate, (iso)stearyl (meth)acrylate, and (iso)behenyl (meth)acrylate are preferred, 2-ethylhexyl (meth)acrylate, (iso)dodecyl (meth)acrylate, and (iso)stearyl (meth)acrylate are more preferred, (iso)dodecyl (meth)acrylate and (iso)stearyl (meth)acrylate are even more preferred, and (iso)stearyl (meth)acrylate is still more preferred. Here, "alkyl (meth)acrylate" refers to alkyl acrylate or alkyl methacrylate. Furthermore, "(iso)" in the alkyl moiety refers to normal alkyl or isoalkyl.

[0064] From the viewpoint of suppressing the degree of gloss unevenness, the amount of the (meth)acrylic compound is preferably 5% by mass or more and 50% by mass or less, more preferably 10% by mass or more and 45% by mass or less, and particularly preferably 15% by mass or more and 40% by mass or less, of the raw material monomers of the styrene-acrylic copolymer segment. From the viewpoint of suppressing the degree of gloss unevenness, the content of the monomer units derived from the (meth)acrylic compound is preferably 5% by mass or more and 50% by mass or less, more preferably 10% by mass or more and 45% by mass or less, and particularly preferably 15% by mass or more and 40% by mass or less, relative to the total mass of the styrene-acrylic copolymer segment.

[0065] Examples of other raw material monomers include ethylenically unsaturated monoolefins such as ethylene and propylene; conjugated dienes such as butadiene; halovinyl compounds such as vinyl chloride; vinyl esters such as vinyl acetate and vinyl propionate; aminoalkyl (meth)acrylate esters such as dimethylaminoethyl (meth)acrylate; vinyl ethers such as methyl vinyl ether; vinylidene halides such as vinylidene chloride; and N-vinyl compounds such as N-vinylpyrrolidone.

[0066] From the viewpoint of image density, the hybrid resin preferably contains a unit derived from a bireactive monomer. When a bireactive monomer is used as a raw material monomer for the hybrid resin, the bireactive monomer reacts with a polyester resin segment, a styrene-acrylic copolymer segment, or each of these raw material monomers to form a bonding point between the polyester resin segment and the styrene-acrylic copolymer segment. The term "unit derived from a bireactive monomer" refers to a unit in which the functional group, vinyl moiety of a bireactive monomer, has reacted. Examples of the bireactive monomer include vinyl monomers having at least one functional group selected from the group consisting of a hydroxy group, a carboxy group, an epoxy group, a primary amino group, and a secondary amino group in the molecule. Among these, from the viewpoint of reactivity, vinyl monomers having a hydroxy group or a carboxy group are preferred, and vinyl monomers having a carboxy group are more preferred. Examples of the bireactive monomer include acrylic acid, methacrylic acid, fumaric acid, maleic acid, etc. Among these, from the viewpoint of reactivity in both the polycondensation reaction and the addition polymerization reaction, acrylic acid and methacrylic acid are preferred, and acrylic acid is more preferred.

[0067] From the viewpoint of further improving image density, the content of the unit derived from the bireactive monomer is preferably 1 part by mol or more, more preferably 5 parts by mol or more, even more preferably 8 parts by mol or more, and is preferably 30 parts by mol or less, more preferably 25 parts by mol or less, even more preferably 20 parts by mol or less, relative to 100 parts by mol of the alcohol component of the polyester resin segment of the hybrid resin. When a bireactive monomer is used and the amount of each segment in the hybrid resin is calculated, the structural unit derived from the bireactive monomer is calculated as being contained in the polyester resin segment.

[0068] From the viewpoint of suppressing the degree of gloss unevenness, the amount of polyester resin segments in the hybrid resin is preferably 40% by mass or more, more preferably 50% by mass or more, and even more preferably 55% by mass or more, relative to the total mass of the hybrid resin, and is preferably 95% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less. From the viewpoint of suppressing the degree of gloss unevenness, the amount of the styrene-acrylic copolymer segment in the hybrid resin is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more, relative to the total mass of the hybrid resin, and is preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 45% by mass or less. From the viewpoint of suppressing the degree of gloss unevenness, the total amount of the polyester resin segment and the styrene-acrylic copolymer segment in the hybrid resin is preferably 80% by mass or more and 100% by mass or less, more preferably 90% by mass or more and 100% by mass or less, even more preferably 93% by mass or more and 100% by mass or less, and particularly preferably 95% by mass or more and 100% by mass or less, based on the total mass of the hybrid resin.

[0069] From the viewpoint of suppressing the degree of gloss unevenness, the softening temperature Tm of the hybrid resin is preferably 70°C or higher, more preferably 90°C or higher, even more preferably 100°C or higher, and is preferably 140°C or lower, more preferably 130°C or lower, even more preferably 125°C or lower. The softening temperature Tm of the resin was measured using a flow tester (Shimadzu Corporation: CFT-500C) under a load of 10 kgf / cm 2 The nozzle diameter is 1 mm, the nozzle length is 1 mm, the sample is preheated to 80°C for 5 minutes, the temperature is increased at a rate of 6°C / min, and 1 g of sample is measured and recorded. The softening temperature is the temperature at 1 / 2 the height of the S-shaped curve in the plunger depression amount-temperature curve of the flow tester (1 / 2 outflow temperature).

[0070] From the viewpoint of suppressing the degree of gloss unevenness in the obtained image, the glass transition temperature of the hybrid resin is preferably 30°C or higher, more preferably 35°C or higher, even more preferably 40°C or higher, and is preferably 70°C or lower, more preferably 60°C or lower, even more preferably 55°C or lower. The glass transition temperature Tg of the resin is measured by the method described below.

[0071] From the viewpoint of suppressing the degree of gloss unevenness, the acid value of the hybrid resin is preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g or more, even more preferably 15 mgKOH / g or more, and is preferably 40 mgKOH / g or less, more preferably 35 mgKOH / g or less, even more preferably 30 mgKOH / g or less. The acid value represents the number of milligrams of potassium hydroxide required to neutralize acid groups (e.g., carboxy groups) in 1 g of sample. The acid value in this embodiment is measured in accordance with the method (potentiometric titration) defined in JIS K0070-1992. For neutralized samples, the neutralizing agent is removed under reduced pressure (and heating may be used), or the sample is treated with an acid to return it to an acid group (e.g., a carboxy group) before measurement. If the sample is insoluble, a solvent such as dioxane or tetrahydrofuran (THF) is used.

[0072] The softening point, glass transition temperature, and acid value of the hybrid resin can be appropriately adjusted by adjusting the types and amounts of raw material monomers used, as well as production conditions such as reaction temperature, reaction time, and cooling rate, and these values ​​can be determined by the methods described in the examples. When two or more hybrid resins are used in combination, the softening point, glass transition temperature, and acid value of the resulting mixture are preferably within the above-mentioned ranges.

[0073] Methods for producing the hybrid resin include, for example, polycondensation of a polycarboxylic acid and a polyhydric alcohol, and addition polymerization of raw material monomers of a styrene-acrylic copolymer segment and a bireactive monomer. More specifically, the following methods (i) to (iii) can be mentioned. (i) A method in which a polycondensation reaction of a polycarboxylic acid and a polyhydric alcohol is followed by an addition polymerization reaction of a raw material monomer for a styrene-acrylic copolymer segment and a bireactive monomer. From the viewpoint of reactivity, it is preferable that a bireactive monomer is supplied to the reaction system together with the raw material monomers of the styrene-acrylic copolymer segment. From the viewpoint of reactivity, a catalyst such as an esterification catalyst or an esterification promoter may be used, and further, a radical polymerization initiator and a radical polymerization inhibitor may be used. From the viewpoint of further promoting the polycondensation reaction and, if necessary, the reaction with the bireactive monomer, it is preferred that a part of the carboxylic acid component is subjected to the polycondensation reaction, and then an addition polymerization reaction is carried out, after which the reaction temperature is increased again, and the remainder is added to the reaction system.

[0074] It can also be produced by the following method (ii) or (iii). (ii) A method in which an addition polymerization reaction is carried out using raw material monomers for the styrene-acrylic copolymer segment and a bireactive monomer, followed by a polycondensation reaction using raw material monomers for the polyester resin segment. (iii) A method in which a polycondensation reaction of a polycarboxylic acid and a polyhydric alcohol and an addition polymerization reaction of a raw material monomer for a styrene-acrylic copolymer segment and a bireactive monomer are carried out in parallel. The polycondensation reaction and the addition polymerization reaction in the above methods (i) to (iii) are preferably carried out in the same vessel. The hybrid resin can be produced by the above method (i) or (ii) by polycondensation. The above method (i) is more preferred because it provides a high degree of freedom in the reaction temperature.

[0075] In the polycondensation reaction, polycarboxylic acids and polyhydric alcohols are polycondensed. If necessary, polycondensation may be carried out using an esterification catalyst such as tin(II) di(2-ethylhexanoate), dibutyltin oxide, or titanium diisopropyl bistriethanolamine in an amount of 0.01 to 5 parts by mass per 100 parts by mass of the total amount of polycarboxylic acids and polyhydric alcohols; an esterification promoter such as gallic acid (equivalent to 3,4,5-trihydroxybenzoic acid) in an amount of 0.001 to 0.5 parts by mass per 100 parts by mass of the total amount of polycarboxylic acids and polyhydric alcohols; and, if necessary, a radical polymerization inhibitor such as 4-tert-butylcatechol in an amount of 0.001 to 0.5 parts by mass per 100 parts by mass of the total amount of polycarboxylic acids and polyhydric alcohols. The temperature of the polycondensation reaction is preferably 120°C or higher, more preferably 160°C or higher, and even more preferably 180°C or higher, and is preferably 250°C or lower, and more preferably 230°C or lower. The polycondensation may be carried out in an inert gas atmosphere.

[0076] In the addition polymerization reaction, raw material monomers for the styrene-acrylic copolymer segment and a bireactive monomer are addition polymerized. The temperature of the addition polymerization reaction is preferably 110° C. or higher, more preferably 130° C. or higher, and preferably 220° C. or lower, more preferably 200° C. or lower. It is also preferable to reduce the pressure of the reaction system in the latter half of the polymerization to promote the reaction.

[0077] As the polymerization initiator for the addition polymerization reaction, known radical polymerization initiators such as peroxides such as dibutyl peroxide, persulfates such as sodium persulfate, and azo compounds such as 2,2'-azobis(2,4-dimethylvaleronitrile) can be used. The amount of the radical polymerization initiator used is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and preferably 20 parts by mass or less, more preferably 15 parts by mass or less, relative to 100 parts by mass of the raw material monomers of the styrene-acrylic copolymer segment.

[0078] The crystalline resin will now be described. 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, etc.) Among these, crystalline polyester resins are preferred in terms of the mechanical strength and low-temperature fixability of the toner.

[0079] The crystalline polyester resin may be, for example, a polycondensate of a polycarboxylic acid and a polyhydric alcohol. Note that, as the crystalline polyester resin, a commercially available product or a synthesized product may be used. Here, the crystalline polyester resin is preferably a polycondensate using a polymerizable monomer having a linear aliphatic group rather than a polymerizable monomer having an aromatic group, since it easily forms a crystalline structure.

[0080] Examples of polycarboxylic acids include aliphatic dicarboxylic acids (e.g., oxalic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, etc.), aromatic dicarboxylic acids (e.g., dibasic acids such as phthalic acid, isophthalic acid, terephthalic acid, and naphthalene-2,6-dicarboxylic acid), anhydrides thereof, and lower alkyl esters thereof (e.g., having 1 to 5 carbon atoms). The polycarboxylic acid may be a tricarboxylic or higher carboxylic acid having a crosslinked or branched structure in combination with a dicarboxylic acid. Examples of the tricarboxylic acid include aromatic carboxylic acids (e.g., 1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, etc.), anhydrides thereof, and lower alkyl esters thereof (e.g., having 1 to 5 carbon atoms). As the polycarboxylic acid, a dicarboxylic acid having a sulfonic acid group and a dicarboxylic acid having an ethylenic double bond may be used in combination with these dicarboxylic acids. The polycarboxylic acids may be used alone or in combination of two or more.

[0081] Examples of polyhydric alcohols include aliphatic diols (for example, straight-chain aliphatic diols having 7 to 20 carbon atoms in the main chain). Examples of aliphatic diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, and 1,14-eicosanedecanediol. Among these, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferred as aliphatic diols. The polyhydric alcohol may be a trihydric or higher alcohol having a crosslinked or branched structure, such as glycerin, trimethylolethane, trimethylolpropane, or pentaerythritol, in combination with the diol. The polyhydric alcohols may be used alone or in combination of two or more.

[0082] Here, the polyhydric alcohol has an aliphatic diol content of 80 mol % or more, preferably 90 mol % or more.

[0083] The crystalline polyester resin can be obtained by a known manufacturing method, for example, in the same manner as the amorphous polyester.

[0084] The characteristics of the crystalline resin will be explained. The melting temperature of the crystalline resin is preferably 50°C or higher and 100°C or lower, more preferably 55°C or higher and 90°C or lower, and even more preferably 60°C or higher and 85°C or lower. The melting temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC) using the "melting peak temperature" described in the method for determining the melting temperature in JIS K7121-1987 "Method for measuring transition temperatures of plastics."

[0085] The weight average molecular weight (Mw) of the crystalline resin is preferably 6,000 or more and 35,000 or less.

[0086] The content of the binder resin is, for example, preferably 40% by mass to 95% by mass, more preferably 50% by mass to 90% by mass, and even more preferably 60% by mass to 85% by mass, based on the total mass of the toner particles.

[0087] -Coloring agent- Examples of colorants include carbon black, chrome yellow, Hansa Yellow, benzidine yellow, threne yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, Balkan orange, watch young red, permanent red, brilliant carmine 3B, brilliant carmine 6B, DuPont oil red, pyrazolone red, lithol red, rhodamine B lake, lake red C, pigment red, rose bengal, aniline blue, ultramarine blue, and the like. Examples of the dye include various pigments such as phosphorus blue, chalco 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, aniline black-based, polymethine-based, triphenylmethane-based, diphenylmethane-based, and thiazole-based dyes. The colorant may be used alone or in combination of two or more kinds.

[0088] The colorant may be surface-treated as needed, or may be used in combination with a dispersant. Furthermore, a plurality of colorants may be used in combination.

[0089] The content of the colorant is, for example, preferably from 1% by mass to 30% by mass, and more preferably from 3% by mass to 15% by mass, based on the total mass of the toner particles.

[0090] -Mold release agent- Examples of release agents 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.

[0091] The melting temperature of the release agent is preferably 50°C or higher and 110°C or lower, and more preferably 60°C or higher and 100°C or lower. The melting temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC) by using the "melting peak temperature" as described in the method for determining the melting temperature in JIS K 7121-1987 "Method for measuring transition temperatures of plastics."

[0092] In particular, it is preferable to use an ester-based wax as the release agent from the viewpoint of suppressing uneven gloss of the image. The ester wax is a wax having an ester bond. The ester wax may be any of a monoester, diester, triester, and tetraester, and any known natural or synthetic ester wax can be used. Examples of ester waxes include ester compounds of higher fatty acids (such as fatty acids having 10 or more carbon atoms) and monohydric or polyhydric aliphatic alcohols (such as aliphatic alcohols having 8 or more carbon atoms), and have a melting temperature of 60°C or higher and 110°C or lower (preferably 65°C or higher and 100°C or lower, more preferably 70°C or higher and 95°C or lower). Examples of ester waxes include ester compounds of higher fatty acids (caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, oleic acid, etc.) with alcohols (monohydric alcohols such as methanol, ethanol, propanol, isopropanol, butanol, capryl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, and oleyl alcohol; and polyhydric alcohols such as glycerin, ethylene glycol, propylene glycol, sorbitol, and pentaerythritol). Specific examples include carnauba wax, rice wax, candelilla wax, jojoba oil, Japan wax, beeswax, privet wax, lanolin, and montan acid ester wax.

[0093] In toner particles in which at least two crystalline resin domains satisfy conditions (A), (B1), (B2), (C), and (D), it is preferable that, when the cross section of the toner particle is observed, the domain of the release agent is present inside the toner particle to a depth of 50 nm or more from the surface of the toner particle. In other words, when the cross section of the toner particle is observed, the shortest distance between the domain of the release agent present in the toner particle and the surface (i.e., the outer edge) of the toner particle is 50 nm or more. The presence of a domain of the release agent at a depth of 50 nm or more from the surface of the toner particle means that the domain of the release agent is not exposed on the surface of the toner particle. If the domain of the release agent is exposed on the surface of the toner particle, the external additive will be unevenly distributed and adhere to the exposed position of the release agent. Therefore, if the domain of the release agent is present at a depth of 50 nm or more from the surface of the toner particle, the external additive will be more easily adhered in a nearly uniform state, which will help to suppress uneven melting of the toner particles during fixing. This will help to suppress uneven gloss of the image.

[0094] The presence of the domain of the release agent at a depth of 50 nm or more from the surface of the toner particle can be confirmed by the above-described method for observing the cross section of the toner particle.

[0095] From the viewpoint of suppressing the degree of gloss unevenness in an image, the proportion of toner particles in which at least two crystalline resin domains satisfy the above conditions and the release agent domains exist at a depth of 50 nm or more from the surface of the toner particles is preferably 40% by number or more, more preferably 70% by number or more, even more preferably 80% by number or more, and particularly preferably 90% by number or more, of all toner particles. Ideally, the proportion of toner particles satisfying each of the above conditions is 100% by number.

[0096] The content of the release agent is, for example, preferably 1% by mass or more and 20% by mass or less, and more preferably 5% by mass or more and 15% by mass or less, based on the total mass of the toner particles.

[0097] -Other additives- Examples of other additives include well-known additives such as magnetic materials, charge control agents, inorganic powders, etc. These additives are contained in the toner particles as internal additives.

[0098] -Characteristics of toner particles, etc.- 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 part (core particle) and a coating layer (shell layer) that coats the core part. Here, the toner particles having a core-shell structure may be composed of, for example, a core containing a binder resin and, if necessary, other additives such as a colorant and a release agent, and a coating layer containing the binder resin.

[0099] The volume average particle size (D50v) of the toner particles is preferably 2 μm or more and 15 μm or less, and more preferably 4 μm or more and 8 μm or less.

[0100] The various average particle sizes and particle size distribution indices of the toner particles are measured using a Coulter Multisizer II (manufactured by Beckman Coulter), and the electrolyte is measured using an ISOTON-II (manufactured by Beckman Coulter). For the measurement, 0.5 mg to 50 mg of the sample to be measured is added to 2 ml of a 5% aqueous solution of a surfactant (preferably sodium alkylbenzene sulfonate) as a dispersant, and this is then added to 100 ml to 150 ml of the electrolyte. The electrolyte solution containing the suspended sample is dispersed for 1 minute using an ultrasonic disperser, and the particle size distribution of particles with a particle size range of 2 μm to 60 μm is measured using a Coulter Multisizer II with an aperture diameter of 100 μm. The number of particles sampled is 50,000. Based on the particle size distribution measured, cumulative distributions of volume and number are drawn for each divided particle size range (channel) from the smallest diameter side, and the particle size at 16% of the cumulative total is defined as the volume particle size D16v, the number particle size D16p, the particle size at 50% of the cumulative total as the volume average particle size D50v, the cumulative number average particle size D50p, and the particle size at 84% of the cumulative total as the volume particle size D84v and the number particle size D84p. Using these, the volumetric particle size distribution index (GSDv) is (D84v / D16v) 1 / 2 , the number particle size distribution index (GSDp) is (D84p / D16p) 1 / 2 It is calculated as:

[0101] The average circularity of the toner particles is preferably 0.94 or more and 1.00 or less, and more preferably 0.95 or more and 0.98 or less.

[0102] The average circularity of toner particles is calculated by (circular equivalent perimeter) / (perimeter) [(perimeter of a circle having the same projected area as the particle image) / (perimeter of the particle projected image)]. Specifically, this value is measured by the following method. First, the toner particles to be measured are sucked and collected, forming a flat flow, and a still image of the particles is captured by instantaneously activating a strobe light, and the particle image is analyzed using a flow-type particle image analyzer (FPIA-3000 manufactured by Sysmex Corporation).The number of samples to be sampled when calculating the average circularity is 3,500. When the toner contains external additives, the toner (developer) to be measured is dispersed in water containing a surfactant, and then ultrasonic treatment is performed to obtain toner particles from which the external additives have been removed.

[0103] (external additives) Examples of external additives include inorganic particles such as SiO2, TiO2, Al2O3, CuO, ZnO, SnO2, CeO2, Fe2O3, MgO, BaO, CaO, KO, Na2O, ZrO2, CaO·SiO2, KO·(TiO2)n, Al2O3·2SiO2, CaCO3, MgCO3, BaSO4, and MgSO4.

[0104] The surfaces of inorganic particles as external additives are preferably subjected to a hydrophobic treatment. The hydrophobic treatment is carried out, for example, by immersing the inorganic particles in a hydrophobic treatment agent. The hydrophobic treatment agent is not particularly limited, and examples thereof include silane coupling agents, silicone oils, titanate coupling agents, and aluminum coupling agents. These may be used alone or in combination of two or more. The amount of the hydrophobic treatment agent is usually, for example, 1 part by mass or more and 10 parts by mass or less per 100 parts by mass of the inorganic particles.

[0105] Examples of external additives include resin particles (resin particles such as polystyrene, polymethyl methacrylate (PMMA), and melamine resin), cleaning agents (for example, metal salts of higher fatty acids such as zinc stearate, and particles of fluorine-based polymers).

[0106] The amount of the external additive added is, for example, preferably 0.01% by mass or more and 5% by mass or less, and more preferably 0.01% by mass or more and 2.0% by mass or less, based on the toner particles.

[0107] (Toner characteristics) In the toner according to this embodiment, the maximum endothermic peak temperature during the first temperature rise measured by a differential scanning calorimeter (DSC) is preferably 58° C. or more and 75° C. or less. By setting the maximum endothermic peak temperature of the toner to 58° C. or more and 75° C. or less, the low-temperature fixability of the toner is improved.

[0108] The maximum endothermic peak temperature of the toner during the first temperature rise is measured by a differential scanning calorimeter (DSC) as follows. A PerkinElmer DSC-7 differential scanning calorimeter is used, and the melting points of indium and zinc are used to correct the temperature of the detector, and the heat of fusion of indium is used to correct the heat quantity. An aluminum pan is used for the sample, and an empty pan is set as a control. The temperature is raised from room temperature to 150°C at a rate of 10°C / min. The temperature at which the maximum endothermic peak occurs is then determined in the resulting endothermic curve.

[0109] (Toner manufacturing method) Next, a method for producing the toner according to this embodiment will be described. The toner according to this exemplary embodiment is obtained by producing toner particles and then externally adding an external additive to the toner particles.

[0110] The toner particles may be produced by any of a dry production method (for example, a kneading and pulverization method) and a wet production method (for example, an aggregation and coalescence method, a suspension polymerization method, a dissolution and suspension method). The method for producing the toner particles is not particularly limited, and any well-known production method may be used. Among these, from the viewpoint of making the domains of the crystalline resin satisfy the above conditions, it is preferable to obtain toner particles by the aggregation and coalescence method.

[0111] Specifically, for example, when toner particles are produced by the aggregation and coalescence method, a step of preparing an amorphous resin particle dispersion liquid in which amorphous resin particles are dispersed and a crystalline resin particle dispersion liquid in which crystalline resin particles are dispersed (a resin particle dispersion liquid preparation step); a step of aggregating amorphous resin particles (and, if necessary, a colorant, a release agent, etc.) in an amorphous resin particle dispersion (in a dispersion obtained by mixing, if necessary, a colorant dispersion and a release agent dispersion) to form first aggregated particles (first aggregated particle forming step); a step of forming second aggregated particles by repeating an operation of mixing the aggregated particle dispersion with an amorphous resin particle dispersion and a crystalline resin particle dispersion (or mixing the aggregated particle dispersion with a mixed liquid of the amorphous resin particle dispersion and the crystalline resin particle dispersion) two or more times to form second aggregated particles (second aggregated particle forming step), after obtaining the aggregated particle dispersion in which the first aggregated particles are dispersed; a step of forming third aggregated particles by mixing the aggregated particle dispersion liquid with an amorphous resin particle dispersion liquid after obtaining the aggregated particle dispersion liquid in which the second aggregated particles are dispersed, and aggregating the second aggregated particles so that the amorphous resin particles adhere to the surfaces of the second aggregated particles (third aggregated particle forming step); a step of heating the aggregated particle dispersion in which the third aggregated particles are dispersed to fuse and coalesce the aggregated particles, and then sequentially performing rapid cooling, reheating, and slow cooling to form toner particles (fusion and coalescence step); Toner particles are produced through the above steps.

[0112] Each step will be described in detail below. In the following description, a method for obtaining toner particles containing a colorant and a release agent will be described, but the colorant and the release agent are used as needed. Of course, additives other than the colorant and the release agent may also be used.

[0113] -Resin particle dispersion preparation process- First, along with each resin particle dispersion liquid (amorphous resin particle dispersion liquid and crystalline resin particle dispersion liquid) in which each resin particle that will become the binder resin is dispersed, for example, a colorant particle dispersion liquid in which colorant particles are dispersed and a release agent particle dispersion liquid in which release agent particles are dispersed are prepared.

[0114] Here, the resin particle dispersion liquid is prepared, for example, by dispersing resin particles in a dispersion medium using a surfactant.

[0115] Examples of the dispersion medium used in the resin particle dispersion include aqueous media. Examples of aqueous media include water such as distilled water and ion-exchanged water, alcohols, etc. These may be used alone or in combination of two or more.

[0116] Examples of surfactants include anionic surfactants such as sulfate ester salts, sulfonate salts, phosphate esters, and soaps; cationic surfactants such as amine salts and quaternary ammonium salts; and nonionic surfactants such as polyethylene glycols, alkylphenol ethylene oxide adducts, and polyhydric alcohols. Among these, anionic surfactants and cationic surfactants are particularly preferred. Nonionic surfactants may be used in combination with anionic surfactants or cationic surfactants. The surfactants may be used alone or in combination of two or more.

[0117] In the resin particle dispersion, resin particles can be dispersed in a dispersion medium by a general dispersion method such as a rotary shear homogenizer, a ball mill having a medium, a sand mill, a dyno mill, etc. Depending on the type of resin particles, the resin particles may be dispersed in the resin particle dispersion by, for example, a phase inversion emulsification method. The phase inversion emulsification method involves dissolving the resin to be dispersed in a hydrophobic organic solvent in which the resin is soluble, adding a base to the organic continuous phase (O phase) to neutralize it, and then adding an aqueous medium (W phase), thereby converting the resin from W / O to O / W (so-called phase inversion) and forming a discontinuous phase, and dispersing the resin in particulate form in the aqueous medium.

[0118] The volume average particle size of the resin particles dispersed in the resin particle dispersion is, for example, preferably from 0.01 μm to 1 μm, more preferably from 0.08 μm to 0.8 μm, and even more preferably from 0.1 μm to 0.6 μm. The volume average particle size of the resin particles is measured using a particle size distribution obtained by measurement with a laser diffraction particle size distribution analyzer (e.g., LA-700 manufactured by Horiba, Ltd.), and the cumulative distribution for the volume of the divided particle size range (channel) is subtracted from the small particle size side, and the particle size at which the cumulative 50% of all particles is measured is defined as the volume average particle size D50v. The volume average particle sizes of particles in other dispersions are also measured in the same way.

[0119] The content of resin particles contained in the resin particle dispersion is, for example, preferably from 5% by mass to 50% by mass, and more preferably from 10% by mass to 40% by mass.

[0120] Note that, for example, a colorant particle dispersion and a release agent particle dispersion are also prepared in the same manner as the resin particle dispersion. That is, the volume average particle size, dispersion medium, dispersion method, and particle content of the particles in the resin particle dispersion are the same for the colorant particles dispersed in the colorant particle dispersion and the release agent particles dispersed in the release agent particle dispersion.

[0121] -First agglomerated particle formation process- Next, the colorant particle dispersion and the release agent particle dispersion are mixed together with the amorphous resin particle dispersion. Then, in the mixed dispersion, the amorphous resin particles, the colorant particles, and the release agent particles are hetero-aggregated to form first aggregate particles containing the amorphous resin particles, the colorant particles, and the release agent particles and having a diameter close to that of the target toner particles.

[0122] Specifically, for example, an aggregating agent is added to the mixed 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), and a dispersion stabilizer is added as necessary.Then, the mixed dispersion is heated to the glass transition temperature of the resin particles (specifically, for example, a temperature between the glass transition temperature of the resin particles -30°C and the glass transition temperature -10°C), and the particles dispersed in the mixed dispersion are aggregated to form first aggregated particles. In the first aggregate particle formation step, for example, the mixed dispersion may be stirred with a rotary shear homogenizer, the aggregating agent may be added at room temperature (e.g., 25°C), the pH of the mixed dispersion may be adjusted to an acidic value (e.g., a pH of 2 or more and 5 or less), a dispersion stabilizer may be added as needed, and then the heating may be carried out.

[0123] Examples of the flocculant include a surfactant having a polarity opposite to that of the surfactant used as the dispersant added to the mixed dispersion, an inorganic metal salt, and a divalent or higher metal complex. In particular, when a metal complex is used as the flocculant, the amount of surfactant used can be reduced and the charging characteristics can be improved. If necessary, an additive that forms a complex or a similar bond with the metal ions of the flocculant may be used, and a chelating agent is preferably used as this additive.

[0124] Examples of inorganic metal salts include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate, as well as inorganic metal salt polymers such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. The chelating agent may be a water-soluble chelating agent, such as hydroxycarboxylic acid (e.g., tartaric acid, citric acid, gluconic acid), iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA), etc. The amount of the chelating agent added is, for example, preferably 0.01 parts by mass or more and 5.0 parts by mass or less, and more preferably 0.1 parts by mass or more and less than 3.0 parts by mass, per 100 parts by mass of the amorphous resin particles.

[0125] -Second agglomerated particle formation process- Next, after obtaining an aggregated particle dispersion in which the first aggregated particles are dispersed, the aggregated particle dispersion is mixed with an amorphous resin particle dispersion and a crystalline resin particle dispersion, or the aggregated particle dispersion may be mixed with a mixed liquid of the amorphous resin particle dispersion and the crystalline resin particle dispersion.

[0126] Then, in the dispersion liquid in which the first aggregated particles, amorphous resin particles, and crystalline resin particles are dispersed, the amorphous resin particles and crystalline resin particles are aggregated on the surfaces of the first aggregated particles. Specifically, for example, in the first aggregate particle formation step, when the first aggregate particles reach a target particle size, an amorphous resin particle dispersion and a crystalline resin particle dispersion are added to the first aggregate particle dispersion, and the dispersion is heated at a temperature equal to or lower than the glass transition temperature of the amorphous resin particles. This aggregation operation is repeated two or more times to form second aggregate particles.

[0127] -Third agglomerated particle formation process- After obtaining the aggregated particle dispersion in which the second aggregated particles are dispersed, the aggregated particle dispersion and the amorphous resin particle dispersion are mixed.

[0128] Then, in the dispersion liquid in which the second aggregated particles and the amorphous resin particles are dispersed, the amorphous resin particles are aggregated on the surfaces of the second aggregated particles. Specifically, for example, in the second aggregate particle formation step, when the second aggregate particles reach a target particle size, an amorphous resin particle dispersion is added to the second aggregate particle dispersion, and this dispersion is heated at a temperature equal to or lower than the glass transition temperature of the amorphous resin particles. Then, the pH of the dispersion is adjusted to stop the progress of aggregation.

[0129] -Fusion / coalescence process- Next, the third aggregate particle dispersion liquid in which the third aggregate particles are dispersed is heated, for example, to a temperature equal to or higher than the glass transition temperature of the amorphous resin particles (for example, a temperature 10 to 30°C higher than the glass transition temperature of the amorphous resin particles), to fuse and coalesce the aggregated particles and form toner particles.

[0130] Here, after fusing and coalescing the aggregated particles by heating, it is advisable to cool them to 30°C at a cooling rate of 5°C / min to 40°C / min. Rapid cooling after carrying out the third aggregate particle formation step makes the toner particle surface more likely to shrink, making them more susceptible to cracking. It is presumed that carrying out the rapid cooling step under the above conditions makes it easier for cracks to form from the inside of the toner particle toward the toner surface. Next, the temperature is raised again at a rate of 0.1°C / min to 2°C / min, and maintained at a temperature of at least 5°C below the melting temperature of the crystalline resin for 10 minutes or more. After that, by gradually cooling at a rate of 0.1°C / min to 1°C / min, the crystalline resin domains grow in the crack direction, from the inside of the toner particle toward the surface, and the crystalline resin domains satisfy the above conditions. Furthermore, for example, if the temperature is increased again to a temperature equal to or higher than the melting temperature of the release agent, there is a high possibility that domains of the release agent will grow up to the vicinity of the toner particle surface. Therefore, the heating temperature after the temperature is increased again is preferably at least 5°C higher than the melting temperature of the crystalline resin but equal to or lower than the melting temperature of the release agent.

[0131] Through the above steps, toner particles are obtained. In addition to the above-mentioned aggregation-coalescence method, if the rapid cooling, reheating, and slow cooling are carried out after the toner particles are produced, the domains of the crystalline resin will satisfy the above-mentioned conditions.

[0132] After the fusion and coalescence process, the toner particles formed in the solution are subjected to a known washing process, a solid-liquid separation process, and a drying process to obtain dry toner particles. In the washing step, it is preferable to carry out sufficient replacement washing with ion-exchanged water from the viewpoint of electrostatic chargeability. Furthermore, the solid-liquid separation step is not particularly limited, but from the viewpoint of productivity, it is preferable to carry out suction filtration, pressure filtration, etc. Furthermore, in the drying step, there is no particular limitation on the method, but from the viewpoint of productivity, it is preferable to carry out freeze drying, flash drying, fluidized drying, vibration-type fluidized drying, etc.

[0133] The toner according to this embodiment is produced by, for example, adding an external additive to the obtained dry toner particles and mixing them. The mixing can be carried out using, for example, a V blender, a Henschel mixer, a Loedige mixer, or the like. Furthermore, if necessary, coarse particles may be removed from the toner using a vibrating sieve, an air sieve, or the like.

[0134] <Electrostatic image developer> The electrostatic image developer according to this embodiment contains at least the toner according to this embodiment. The electrostatic image developer according to this embodiment may be a one-component developer containing only the toner according to this embodiment, or may be a two-component developer containing the toner mixed with a carrier.

[0135] The carrier is not particularly limited, and examples thereof include known carriers, such as coated carriers in which the surface of a core material made of magnetic powder is coated with a coating resin, magnetic powder dispersion carriers in which magnetic powder is dispersed and blended in a matrix resin, and resin-impregnated carriers in which porous magnetic powder is impregnated with a resin. The magnetic powder dispersion type carrier and the resin impregnated type carrier may be a carrier in which the constituent particles of the carrier are used as a core material and are coated with a coating resin.

[0136] Examples of magnetic powder include magnetic metals such as iron, nickel, and cobalt, and magnetic oxides such as ferrite and magnetite.

[0137] Examples of coating resins and matrix resins include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic acid ester copolymer, straight silicone resins containing organosiloxane bonds or modified products thereof, fluororesins, polyesters, polycarbonates, phenolic resins, and epoxy resins. The coating resin and the matrix resin may contain other additives such as conductive particles. Examples of 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.

[0138] Here, the method of coating the surface of the core material with a coating resin includes a method of coating with a solution for forming a coating layer in which the coating resin and, if necessary, various additives are dissolved in an appropriate solvent. The solvent is not particularly limited and may be selected taking into consideration the coating resin to be used, its applicability, etc. Specific resin coating methods include an immersion method in which the core material is immersed in a solution for forming a coating layer, a spray method in which the solution for forming a coating layer is sprayed onto the surface of the core material, a fluidized bed method in which the solution for forming a coating layer is sprayed onto the core material while it is suspended in flowing air, and a kneader coater method in which the core material of the carrier and the solution for forming a coating layer are mixed in a kneader coater and the solvent is removed.

[0139] In the two-component developer, the mixing ratio (mass ratio) of toner to carrier is preferably toner:carrier=1:100 to 30:100, and more preferably 3:100 to 20:100.

[0140] <Image forming device / image forming method> An image forming apparatus and an image forming method according to this embodiment will be described. The image forming apparatus according to the present embodiment includes an image carrier, a charging unit that charges the surface of the image carrier, an electrostatic image forming unit that forms an electrostatic image on the surface of the charged image carrier, a developing unit that contains an electrostatic image developer and develops the electrostatic image formed on the surface of the image carrier as a toner image using the electrostatic image developer, a transfer unit that transfers the toner image formed on the surface of the image carrier to the surface of a recording medium, and a fixing unit that fixes the toner image transferred to the surface of the recording medium. The electrostatic image developer according to the present embodiment is used as the electrostatic image developer.

[0141] The image forming apparatus according to this embodiment carries out an image forming method (the image forming method according to this embodiment) that includes a charging step of charging the surface of an image carrier, an electrostatic image forming step of forming an electrostatic image on the surface of the charged image carrier, a developing step of developing the electrostatic image formed on the surface of the image carrier as a toner image using the electrostatic image developer according to this embodiment, a transfer step of transferring the toner image formed on the surface of the image carrier to the surface of a recording medium, and a fixing step of fixing the toner image transferred to the surface of the recording medium.

[0142] The image forming apparatus according to the present embodiment may be any of known image forming apparatuses, such as a direct transfer type apparatus that directly transfers a toner image formed on the surface of an image carrier to a recording medium; an intermediate transfer type apparatus that primarily transfers a toner image formed on the surface of an image carrier to the surface of an intermediate transfer medium, and then secondarily transfers the toner image transferred to the surface of the intermediate transfer medium to the surface of a recording medium; an apparatus equipped with a cleaning means that cleans the surface of the image carrier after the transfer of the toner image but before charging; and an apparatus equipped with a discharging means that irradiates the surface of the image carrier with discharging light to discharge it after the transfer of the toner image but before charging. In the case of an intermediate transfer type device, the transfer means is configured to have, for example, an intermediate transfer body onto whose surface a toner image is transferred, a primary transfer means which primarily transfers the toner image formed on the surface of the image carrier onto the surface of the intermediate transfer body, and a secondary transfer means which secondarily transfers the toner image transferred onto the surface of the intermediate transfer body onto the surface of the recording medium.

[0143] In the image forming apparatus according to the present embodiment, for example, a portion including the developing means may have a cartridge structure (process cartridge) that is detachably attached to the image forming apparatus. As the process cartridge, for example, a process cartridge equipped with developing means that accommodates the electrostatic image developer according to the present embodiment is preferably used.

[0144] An example of an image forming apparatus according to the present embodiment will be described below, but the present invention is not limited to this. Note that only the main parts shown in the drawings will be described, and descriptions of other parts will be omitted.

[0145] FIG. 1 is a schematic diagram showing the configuration of an image forming apparatus according to this embodiment. The image forming apparatus shown in Figure 1 includes first through fourth electrophotographic image forming units 10Y, 10M, 10C, and 10K (image forming means) that output images in the colors 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 horizontally spaced a predetermined distance apart from one another. Note that these units 10Y, 10M, 10C, and 10K may also be process cartridges that are detachable from the image forming apparatus.

[0146] Above each of the units 10Y, 10M, 10C, and 10K in the drawing, an intermediate transfer belt 20 serving as an intermediate transfer body extends through each unit. The intermediate transfer belt 20 is wound around a drive roll 22 and a support roll 24 that are spaced apart from each other and arranged from left to right in the drawing, and is configured to run in a direction from the first unit 10Y to the fourth unit 10K. A force is applied to the support roll 24 in a direction away from the drive roll 22 by a spring or the like (not shown), thereby applying tension to the intermediate transfer belt 20 wound around them. In addition, an intermediate transfer body cleaning device 30 is provided on the image carrier side of the intermediate transfer belt 20, facing the drive roll 22. In addition, the developing devices (developing means) 4Y, 4M, 4C, and 4K of the units 10Y, 10M, 10C, and 10K are supplied with toner including four colors of toner, yellow, magenta, cyan, and black, contained in toner cartridges 8Y, 8M, 8C, and 8K, respectively.

[0147] Since the first to fourth units 10Y, 10M, 10C, and 10K have the same configuration, the first unit 10Y, which forms a yellow image and is disposed upstream in the direction of travel of the intermediate transfer belt, will be described here as a representative. Note that parts equivalent to those of the first unit 10Y are given reference numerals with magenta (M), cyan (C), and black (K) instead of yellow (Y), and descriptions of the second to fourth units 10M, 10C, and 10K will be omitted.

[0148] The first unit 10Y has a photoreceptor 1Y that acts as an image carrier. Around the photoreceptor 1Y, there are arranged in this order: a charging roll (an example of a charging means) 2Y that charges the surface of the photoreceptor 1Y to a predetermined potential; an exposure device (an example of an electrostatic image forming means) 3 that exposes the charged surface to a laser beam 3Y based on a color-separated image signal to form an electrostatic image; a developing device (an example of a developing means) 4Y that supplies charged toner to the electrostatic image to develop it; a primary transfer roll 5Y (an example of a primary transfer means) that transfers the developed toner image onto an intermediate transfer belt 20; and a photoreceptor cleaning device (an example of a cleaning means) 6Y that removes toner remaining on the surface of the photoreceptor 1Y after the primary transfer. The primary transfer roll 5Y is disposed inside the intermediate transfer belt 20 and is positioned opposite the photoreceptor 1Y. Furthermore, a bias power supply (not shown) that applies a primary transfer bias is connected to each of the primary transfer rolls 5Y, 5M, 5C, and 5K. Each bias power supply varies the transfer bias applied to each primary transfer roll under the control of a control unit (not shown).

[0149] The operation of forming a yellow image in first unit 10Y will be described below. First, prior to operation, the surface of the photosensitive member 1Y is charged to a potential of −600V to −800V by the charging roll 2Y. The photoconductor 1Y has conductivity (for example, volume resistivity at 20°C: 1×10 -6 The photosensitive layer is formed by laminating a photosensitive layer on a substrate with a resistivity of Ωcm or less. This photosensitive layer normally has a high resistance (the resistance of ordinary resins), but when irradiated with a laser beam 3Y, the resistivity of the irradiated portion changes. Therefore, a laser beam 3Y is output to the charged surface of the photosensitive element 1Y via an exposure device 3 in accordance with image data for yellow sent from a control unit (not shown). The laser beam 3Y is irradiated onto the photosensitive layer on the surface of the photosensitive element 1Y, thereby forming an electrostatic charge image of a yellow image pattern on the surface of the photosensitive element 1Y.

[0150] An electrostatic image is an image formed on the surface of the photosensitive element 1Y by charging it; the laser beam 3Y reduces the resistivity of the irradiated portion of the photosensitive layer, causing the charged charges on the surface of the photosensitive element 1Y to flow, while the charges remain in the portions not irradiated by the laser beam 3Y, forming a so-called negative latent image. The electrostatic image formed on the photoreceptor 1Y is rotated to a predetermined development position as the photoreceptor 1Y travels. At this development position, the electrostatic image on the photoreceptor 1Y is made visible as a toner image (developed image) by the developing device 4Y.

[0151] The developing device 4Y contains an electrostatic image developer containing, for example, at least yellow toner and a carrier. The yellow toner is frictionally charged by being stirred inside the developing device 4Y, and is held on a developer roll (an example of a developer holder) with a charge of the same polarity (negative polarity) as the charge on the photoreceptor 1Y. As the surface of the photoreceptor 1Y passes through the developing device 4Y, the yellow toner electrostatically adheres to the discharged latent image portion on the surface of the photoreceptor 1Y, and the latent image is developed with the yellow toner. The photoreceptor 1Y on which the yellow toner image has been formed continues to travel at a predetermined speed, and the toner image developed on the photoreceptor 1Y is transported to a predetermined primary transfer position.

[0152] When the yellow toner image on the photoreceptor 1Y is transported to the primary transfer, a primary transfer bias is applied to the primary transfer roll 5Y, and an electrostatic force from the photoreceptor 1Y to the primary transfer roll 5Y acts on the toner image, causing the toner image on the photoreceptor 1Y to be transferred onto the intermediate transfer belt 20. The transfer bias applied at this time has a (+) polarity opposite to the (-) polarity of the toner, and in the first unit 10Y, for example, it is controlled to +10 μA by a control unit (not shown). On the other hand, the toner remaining on the photoreceptor 1Y is removed and collected by the photoreceptor cleaning device 6Y.

[0153] Furthermore, the primary transfer bias applied to the primary transfer rolls 5M, 5C, and 5K of the second unit 10M and subsequent units is also controlled in accordance with the first unit. In this way, the intermediate transfer belt 20 onto which the yellow toner image has been transferred by the first unit 10Y is conveyed sequentially through the second to fourth units 10M, 10C, and 10K, and the toner images of each color are transferred onto the intermediate transfer belt 20 in a superimposed manner.

[0154] The intermediate transfer belt 20, onto which the four-color toner images have been multiplex-transferred through the first to fourth units, reaches a secondary transfer section composed of the intermediate transfer belt 20, a support roll 24 in contact with the inner surface of the intermediate transfer belt, and a secondary transfer roll (an example of a secondary transfer means) 26 arranged on the image bearing surface side of the intermediate transfer belt 20. Meanwhile, recording paper (an example of a recording medium) P is fed via a supply mechanism into the gap between the secondary transfer roll 26 and the intermediate transfer belt 20 at a predetermined timing, and a secondary transfer bias is applied to the support roll 24. The transfer bias applied at this time has a negative polarity, the same as the negative polarity of the toner. Electrostatic force from the intermediate transfer belt 20 toward the recording paper P acts on the toner image, transferring the toner image on the intermediate transfer belt 20 onto the recording paper P. The secondary transfer bias at this time is determined according to resistance detected by resistance detection means (not shown) that detects resistance in the secondary transfer section, and is voltage-controlled.

[0155] Thereafter, the recording paper P is sent to the pressure contact portion (nip portion) of a pair of fixing rolls in a fixing device (an example of fixing means) 28, where the toner image is fixed onto the recording paper P, forming a fixed image.

[0156] Examples of the recording paper P onto which the toner image is transferred include plain paper used in electrophotographic copying machines, printers, etc. In addition to the recording paper P, examples of the recording medium include overhead projector sheets and the like. To further improve the smoothness of the image surface after fixing, it is preferable that the surface of the recording paper P is also smooth. For example, coated paper in which the surface of plain paper is coated with resin or the like, or art paper for printing, is preferably used.

[0157] The recording paper P on which the color image has been fixed is conveyed toward the discharge section, and the series of color image forming operations is completed.

[0158] <Process cartridges / toner cartridges> The process cartridge according to this embodiment will be described. The process cartridge according to this embodiment is a process cartridge that is detachably attached to an image forming apparatus and that contains the electrostatic image developer according to this embodiment and is equipped with a developing means that develops an electrostatic image formed on the surface of an image carrier using the electrostatic image developer into a toner image.

[0159] The process cartridge according to this embodiment is not limited to the above configuration, but may also be configured to include a developing device and, if necessary, at least one other means selected from an image carrier, a charging means, an electrostatic image forming means, and a transfer means.

[0160] An example of a process cartridge according to the present embodiment will be described below, but the present invention is not limited to this. Note that only the main parts shown in the drawings will be described, and descriptions of other parts will be omitted.

[0161] FIG. 2 is a schematic diagram showing the configuration of the process cartridge according to the present embodiment. The process cartridge 200 shown in FIG. 2 is configured to integrally combine and hold a photosensitive member 107 (an example of an image carrier), a charging roll 108 (an example of a charging means) provided around the photosensitive member 107, a developing device 111 (an example of a developing means), and a photosensitive member cleaning device 113 (an example of a cleaning means), which are held by a housing 117 provided with, for example, mounting rails 116 and an opening 118 for exposure, and is made into a cartridge. In FIG. 2, 109 denotes an exposure device (an example of an electrostatic image forming means), 112 denotes a transfer device (an example of a transfer means), 115 denotes a fixing device (an example of a fixing means), and 300 denotes recording paper (an example of a recording medium).

[0162] Next, the toner cartridge according to this embodiment will be described. The toner cartridge according to the present embodiment is a toner cartridge that contains the toner according to the present embodiment and is detachably attached to an image forming apparatus. The toner cartridge contains replenishment toner to be supplied to a developing unit provided in the image forming apparatus.

[0163] 1 is an image forming apparatus having a configuration in which toner cartridges 8Y, 8M, 8C, and 8K can be attached and detached, and developing devices 4Y, 4M, 4C, and 4K are connected to the toner cartridges corresponding to each developing device (color) by toner supply pipes (not shown). When the toner stored in a toner cartridge runs low, the toner cartridge is replaced. [Example]

[0164] Hereinafter, the present embodiment will be described in more detail with reference to examples and comparative examples, but the present embodiment is not limited to these examples. Note that "parts" and "%" indicating amounts are based on mass unless otherwise specified.

[0165] <Preparation of amorphous resin> (Preparation of amorphous polyester resin (A)) Terephthalic acid: 70 parts Fumaric acid: 30 parts Ethylene glycol: 41 parts 1,5-pentanediol: 48 parts The above materials were placed in a 5-liter flask equipped with a stirrer, nitrogen inlet tube, temperature sensor, and distillation column. The temperature was raised to 220°C over 1 hour under a nitrogen gas stream, and 1 part of titanium tetraethoxide was added for every 100 parts of the above materials. The temperature was raised to 240°C over 0.5 hours while distilling off the resulting water. The dehydration condensation reaction was continued at that temperature for 1 hour, and then the reaction mixture was cooled. In this way, an amorphous polyester resin (A) with a weight-average molecular weight of 96,000 and a glass transition temperature of 61°C was synthesized.

[0166] <Preparation of amorphous resin particle dispersion> (Preparation of amorphous polyester resin particle dispersion (A1)) A vessel equipped with a temperature control device and a nitrogen purge device was charged with 40 parts of ethyl acetate and 25 parts of 2-butanol to form a mixed solvent. Then, 100 parts of amorphous polyester resin (A) was gradually added and dissolved. A 10% aqueous ammonia solution (equivalent to three times the molar amount of the resin's acid value) was added and stirred for 30 minutes. The vessel was then purged with dry nitrogen, the temperature was maintained at 40°C, and 400 parts of ion-exchanged water was added dropwise at a rate of 2 parts / min while stirring the mixed solution, resulting in emulsification. After the addition was completed, the emulsion was returned to 25°C, yielding a resin particle dispersion containing dispersed resin particles with a volume average particle size of 190 nm. Ion-exchanged water was added to the resin particle dispersion to adjust the solids content to 20%, yielding amorphous polyester resin particle dispersion (A1).

[0167] (Preparation of styrene acrylic resin particle dispersion (SA1)) Styrene: 308 parts n-Butyl acrylate: 100 parts Acrylic acid: 4 parts Dodecanethiol: 3 parts Propanediol diacrylate: 1.5 parts The above components were mixed and dissolved, and the resulting mixture was added to an aqueous solution of 4 parts anionic surfactant (Neogen SC, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) in 550 parts ion-exchanged water, followed by emulsification in a reaction vessel. Next, while mixing for 10 minutes, an aqueous solution of 6 parts ammonium persulfate in 350 parts ion-exchanged water was added, and after nitrogen substitution, the contents of the reaction vessel were heated in an oil bath with stirring until the temperature reached 75°C, and maintained for 5 hours to continue emulsion polymerization. After emulsion polymerization was completed, ion-exchanged water was added to adjust the resin particle concentration to 20%, yielding a styrene-acrylic resin dispersion (SA1) containing dispersed resin particles with an average particle size of 195 nm and a weight-average molecular weight (Mw) of 41,000. The glass transition temperature of the amorphous styrene-acrylic resin was 52°C.

[0168] [Preparation of styrene acrylic modified polyester resin particle dispersion (HB1)] The inside of a four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple was replaced with nitrogen. 5,670 parts of polyoxypropylene(2.2)-2,2-bis(4-hydroxyphenyl)propane, 585 parts of polyoxyethylene(2.0)-2,2-bis(4-hydroxyphenyl)propane, 2,450 parts of terephthalic acid, and 44 parts of tin(II) di(2-ethylhexanoate) were added. The mixture was heated to 235°C under a nitrogen atmosphere with stirring and maintained for 5 hours. The pressure in the flask was then further reduced and maintained at 8.0 kPa for 1 hour. After returning to atmospheric pressure, the mixture was cooled to 190°C, and 42 parts of fumaric acid and 207 parts of trimellitic acid were added. The mixture was maintained at 190°C for 2 hours, and then heated to 210°C over 2 hours. The pressure in the flask was further reduced and maintained at 8.0 kPa for 4 hours to obtain amorphous polyester resin A (polyester resin segment). Next, 800 parts of amorphous polyester resin A was added to a four-neck flask equipped with a condenser, a stirrer, and a thermocouple, and the mixture was stirred at 200 rpm under a nitrogen atmosphere. After that, 100 parts of styrene, 82 parts of butyl acrylate, 16 parts of acrylic acid, 2 parts of 1,10-decanediol diacrylate, and 1.00 parts of toluene were added as addition-polymerizable monomers, and the mixture was mixed for an additional 30 minutes. Furthermore, 6 parts of polyoxyethylene alkyl ether (nonionic surfactant, trade name: Emulgen 430, manufactured by Kao Corporation), 40 parts of a 15% aqueous solution of sodium dodecylbenzenesulfonate (anionic surfactant, trade name: Neopelex G-15, manufactured by Kao Corporation), and 233 parts of 5% potassium hydroxide were added, and the mixture was heated to 95°C with stirring to melt, and mixed at 95°C for 2 hours to obtain a resin mixture solution. Next, while stirring the resin mixture solution, 1,145 parts of ion-exchanged water was added dropwise at a rate of 6 parts / min to obtain an emulsion. Next, the obtained emulsion was cooled to 25°C, passed through a 200-mesh wire screen, and ion-exchanged water was added to adjust the solid content to 20%, thereby obtaining a styrene acrylic-modified polyester resin particle dispersion (HB1). The "mass ratio of the styrene-acrylic copolymer segment to the polyester resin segment (styrene-acrylic copolymer segment / polyester resin segment)" of the synthesized styrene-acrylic modified polyester resin was 10 / 90.

[0169] <Preparation of crystalline resin> (Preparation of Crystalline Polyester Resin (B)) 1,10-decanedicarboxylic acid: 265 parts 1,6-Hexanediol: 168 parts Dibutyltin oxide (catalyst): 0.3 parts by mass The above ingredients were placed in a heated and dried three-necked flask, and the air in the vessel was evacuated to an inert atmosphere with nitrogen gas. The mixture was then mechanically stirred and refluxed at 180°C for 5 hours. The temperature was then gradually increased to 230°C under reduced pressure and stirred for 2 hours. When the mixture became viscous, it was air-cooled to terminate the reaction. Molecular weight measurement (polystyrene equivalent) showed that the weight-average molecular weight (Mw) of the resulting "crystalline polyester resin (B)" was 12,700, and the melting temperature was 73°C.

[0170] <Preparation of Crystalline Polyester Resin Particle Dispersion> (Preparation of Crystalline Polyester Resin Particle Dispersion (B1)) 90 parts by mass of crystalline polyester resin (B), 1.8 parts by mass of ionic surfactant Neogen RK (Dai-ichi Kogyo Seiyaku), and 210 parts by mass of ion-exchanged water were heated to 120°C and thoroughly dispersed using an IKA Ultra-Turrax T50. After that, a dispersion treatment was carried out for 1 hour using a pressure discharge Gaulin homogenizer to obtain a crystalline polyester resin particle dispersion (B1) with a volume average particle size of 190 nm and a solid content of 20 parts by mass.

[0171] (Preparation of Colorant Particle Dispersion) Carbon black (Cabot, Regal 330): 50 parts Ionic surfactant Neogen RK (Dai-ichi Kogyo Seiyaku): 5 parts Ion-exchanged water: 193 parts The above components were mixed and treated for 10 minutes at 240 MPa using an Ultimizer (manufactured by Sugino Machine Co., Ltd.) to prepare a colorant particle dispersion (solid content concentration: 20%).

[0172] <Preparation of Release Agent Particle Dispersion> (Preparation of Release Agent Particle Dispersion (W1)) Ester wax (NOF Corporation WEP-5, melting temperature 85°C): 100 parts Anionic surfactant (Neogen RK, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 1 part Ion-exchanged water: 350 parts The above materials were mixed and heated to 100°C, dispersed using a homogenizer (Ultra Turrax T50 manufactured by IKA), and then dispersed using a Manton-Gaulin high-pressure homogenizer (manufactured by Gaulin) to obtain a release agent particle dispersion (W1) (solid content 20%) in which release agent particles with a volume average particle size of 220 nm were dispersed.

[0173] (Preparation of Release Agent Particle Dispersion (W2)) Paraffin wax (Nippon Seiro Co., Ltd. HNP-0190, melting point 89°C): 100 parts Anionic surfactant (Neogen RK, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 1 part Ion-exchanged water: 350 parts The above materials were mixed and heated to 100°C, dispersed using a homogenizer (Ultra Turrax T50 manufactured by IKA), and then dispersed using a Manton-Gaulin high-pressure homogenizer (manufactured by Gaulin). This gave a release agent particle dispersion (W2) (solid content 20%) in which release agent particles with a volume average particle size of 220 nm were dispersed.

[0174] (Preparation of Release Agent Particle Dispersion (W3)) Polyethylene wax (Toyo ADL PW600, melting temperature 91°C): 100 parts Anionic surfactant (Neogen RK, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 1 part Ion-exchanged water: 350 parts The above materials were mixed and heated to 100°C, dispersed using a homogenizer (Ultra Turrax T50 manufactured by IKA), and then dispersed using a Manton-Gaulin high-pressure homogenizer (manufactured by Gaulin). This gave a release agent particle dispersion (W3) (solid content 20%) in which release agent particles with a volume average particle size of 220 nm were dispersed.

[0175] Example 1 -Production of toner particles- Ion-exchanged water: 215 parts Amorphous polyester resin particle dispersion (A1): 167 parts Crystalline polyester resin particle dispersion (B1): 27 parts Release agent dispersion (W1): 40 parts Colorant dispersion: 20 parts Anionic surfactant (Dai-ichi Kogyo Seiyaku Co., Ltd.: Neogen RK, 20%): 2.8 parts The above components were placed in a 3-liter reaction vessel equipped with a thermometer, pH meter, and stirrer, and the temperature was controlled externally with a mantle heater while maintaining the temperature at 30°C and the stirring speed at 150 rpm for 30 minutes. Then, a 0.3N aqueous nitric acid solution was added to adjust the pH to 3.0 for the coagulation process.

[0176] While dispersing with a homogenizer (Ultra Turrax T50, manufactured by IKA Japan), an aqueous PAC solution prepared by dissolving 0.7 parts of PAC (30% powder, manufactured by Oji Paper Co., Ltd.) in 7 parts of ion-exchanged water was added. The temperature was then raised to 50°C while stirring to produce aggregated particles that would become the cores (hereinafter also referred to as "core aggregated particles"). The particle size of the core aggregated particles was measured using a Coulter Multisizer II (aperture diameter: 50 μm, manufactured by Coulter), and the volume average particle size (D50v) was determined to be 4.9 μm. Subsequently, a mixture of 10 parts of amorphous polyester resin particle dispersion (A1) and 10 parts of crystalline polyester resin particle dispersion (B1) was added. After 30 minutes, a mixture of 10 parts of amorphous polyester resin dispersion (A1) and 10 parts of crystalline polyester resin particle dispersion (B1) was further added. This additional addition was repeated a total of four times, that is, the additional addition of the mixed liquid of 10 parts of the amorphous polyester resin particle dispersion (A1) and 10 parts of the crystalline polyester resin particle dispersion (B1) was carried out four times. Finally, 20 parts of the amorphous polyester resin particle dispersion (A1) was added to adhere the amorphous polyester resin particles to the surfaces of the aggregated particles.

[0177] Next, 20 parts of a 10% NTA (nitrilotriacetic acid) metal salt aqueous solution (Chilest 70, manufactured by Chelest Corporation) was added, and the pH was adjusted to 9.0 with 1N sodium hydroxide solution. The mixture was then heated to 90°C at a rate of 0.05°C / min, held at 90°C for 3 hours, and then cooled to 30°C at a rate of 15°C / min (first cooling). The mixture was then heated again at a rate of 0.2°C / min to 80°C, a temperature above the melting temperature of the crystalline resin minus 5°C, held for 30 minutes, and then slowly cooled to 30°C at a rate of 0.5°C / min (second cooling). The mixture was then filtered to obtain coarse toner particles. The toner particles were then redispersed in ion-exchange water and repeatedly filtered. The filtrate was washed until its electrical conductivity reached 20 μS / cm or less, and then vacuum-dried in a 40°C oven for 5 hours to obtain toner particles with a volume average particle size (D50v) of 5.8 μm.

[0178] -Toner production- 100 parts of the obtained toner particles were mixed with 1.5 parts of hydrophobic silica (RY50, manufactured by Nippon Aerosil Co., Ltd.) using a sample mill at 10,000 rpm for 30 seconds, and then sieved using a vibrating sieve with 45 μm openings to obtain a toner.

[0179] <Examples 2 to 27> Toner particles were prepared in the same manner as in Example 1, except that when the core aggregated particles reached the volume average particle size shown in Table 1, the amorphous polyester resin particle dispersion (A1) and the crystalline polyester resin particle dispersion (B1) were added. However, the cooling rate for the first cooling, the holding temperature after reheating, and the cooling rate for the second cooling were as shown in Table 1. In Example 3, the release agent particle dispersion liquid (W2) was used instead of the release agent particle dispersion liquid (W1) used in Example 1 to prepare toner particles. In Example 4, the release agent particle dispersion liquid (W3) was used instead of the release agent particle dispersion liquid (W1) used in Example 1 to prepare toner particles.

[0180] Example 28 680 parts of amorphous polyester resin (A), 200 parts of crystalline polyester resin (B), 40 parts of carbon black (Regal 330), and 80 parts of ester wax (WEP-5) were thoroughly pre-mixed in a Henschel mixer, melt-kneaded in a two-screw roll mill, cooled, and then finely pulverized in a jet mill. Further, the mixture was classified twice in an air classifier to obtain toner particles. The toner particles were heated to 70°C, which is a temperature 5°C above the melting temperature of the crystalline resin, and held at that temperature for 20 minutes. They were then rapidly cooled to 30°C by air cooling at a rate of 15°C / min. They were then heated again to 70°C, held at that temperature for 30 minutes, and gradually cooled to 30°C by air cooling at a rate of 0.5°C / min to obtain toner particles.

[0181] Example 29 (Preparation of polyester prepolymer) Bisphenol A-ethylene oxide adduct: 182 parts Bisphenol A-propylene oxide adduct: 21 parts Terephthalic acid: 7 parts Isophthalic acid: 85 parts The above monomers were placed in a well-dried, N-purged three-neck flask, heated to 180°C while blowing in N2, and dissolved, then thoroughly mixed. After adding 0.4 parts of dibutyltin oxide, the temperature in the system was raised to 205°C and the reaction was allowed to proceed while maintaining that temperature. During the reaction, small amounts of samples were taken to measure the molecular weight, and the reaction progress was controlled by adjusting the temperature and recovering water under a reduced pressure atmosphere, thereby obtaining the desired condensation product. Next, the temperature was lowered to 175°C, and 8 parts of phthalic anhydride were added, and the reaction was allowed to proceed with stirring under a reduced pressure atmosphere for 3 hours. Into another three-neck flask that had been thoroughly dried and purged with N2, 330 parts of the condensate obtained above, 25 parts of isophorone diisocyanate, and 410 parts of ethyl acetate were placed, and this mixture was heated at 70°C for 5 hours while blowing N2 into it, to obtain a polyester prepolymer having an isocyanate group (hereinafter referred to as "isocyanate-modified polyester prepolymer") as an amorphous resin.

[0182] (Preparation of ketimine compounds) Methyl ethyl ketone: 20 parts Isophoronediamine: 15 parts The above materials were placed in a container and stirred under heating at 58°C to obtain a ketimine compound. (Preparation of black pigment dispersion for oil phase liquid) Carbon black (Cabot, Regal 330): 15 parts Ethyl acetate: 65 parts Solsperse 5000 (Zeneca): 1.2 parts The above components were mixed and dissolved / dispersed using a sand mill to obtain a black pigment dispersion for an oil phase liquid. (Preparation of release agent dispersion for oil phase liquid) 20 parts ester wax (NOF Corporation, WEP-5, melting temperature 85°C) Ethyl acetate: 220 parts The above components were cooled to 18° C. and then wet-pulverized using a microbead type disperser (DCP mill) to obtain a release agent dispersion for the oil phase liquid.

[0183] (Preparation of oil phase liquid) Black pigment dispersion for oil phase: 32 parts Bentonite (Wako Pure Chemical Industries): 8 parts Ethyl acetate: 58 parts The above ingredients were placed in a container and thoroughly mixed. Amorphous polyester resin A: 112 parts Crystalline polyester resin B: 28 parts Release agent dispersion for oil phase: 75 parts The mixture was added and thoroughly stirred to prepare an oil phase liquid.

[0184] (Preparation of styrene acrylic resin particle dispersion (2)) Styrene: 75 parts n-Butyl acrylate: 115 parts Methacrylic acid: 75 parts 8 parts of sodium methacrylate polyoxyalkylene sulfate (Eleminol RS-30, manufactured by Sanyo Chemical Industries, Ltd.) Dodecanethiol: 4 parts The above components were placed in a refluxable reaction vessel and thoroughly mixed with stirring. 800 parts of ion-exchanged water and 1.2 parts of ammonium persulfate were quickly added to the mixture, and while maintaining the temperature below room temperature, the mixture was dispersed and emulsified using a homogenizer (Ultra Turrax T50, manufactured by IKA) to produce a white emulsion. The temperature inside the system was raised to 70°C while stirring and blowing in N2, and emulsion polymerization was continued for 5 hours. After slowly adding 18 parts of a 1% aqueous ammonium persulfate solution, the mixture was maintained at 70°C for 2 hours to complete the polymerization.

[0185] (Preparation of aqueous phase liquid) Styrene acrylic resin particle dispersion (2): 50 parts 170 parts of 2% aqueous solution of Cellogen BS-H (CMC, Daiichi Kogyo Seiyaku Co., Ltd.) Anionic surfactant (Dowfax2A1, manufactured by Dow): 3 parts Ion-exchanged water: 230 parts The above ingredients were thoroughly mixed and stirred to prepare an aqueous phase liquid.

[0186] ·Oil phase liquid: 370 parts Isocyanate-modified polyester prepolymer: 25 parts Ketimine compound: 1.5 parts The above ingredients were placed in a round-bottom stainless steel flask and stirred for 2 minutes using a homogenizer (Ultra Turrax, manufactured by IKA) to prepare a mixed oil phase liquid. 900 parts of the aqueous phase liquid was then added to the flask and quickly emulsified for approximately 2 minutes using a homogenizer (8500 rpm). The emulsion was then stirred using a paddle stirrer at room temperature or below and at normal pressure (1 atmosphere) for approximately 15 minutes to promote particle formation and the urea modification reaction of the polyester resin. After that, nitrogen was introduced into the suspension at 2 m 3 The mixture was stirred at 75°C for 8 hours while blowing in the mixture at a rate of 1 / hour and distilling off the solvent under reduced pressure or removing it under normal pressure, to complete the urea modification reaction. After that, it was rapidly cooled to 30°C at 15°C / min, then heated again to 90°C and held there for 30 minutes, and then gradually cooled to 30°C at 0.5°C / min. After cooling, the suspension of the produced particles was taken out, thoroughly washed with ion-exchanged water, and subjected to solid-liquid separation using Nutsche suction filtration. Next, the particles were redispersed in ion-exchanged water at 35°C and washed with stirring for 15 minutes. This washing procedure was repeated several times, after which solid-liquid separation was performed using Nutsche suction filtration and freeze-dried under vacuum to obtain toner particles. 100 parts by mass of the obtained toner particles were mixed and blended with 1.5 parts by mass of hydrophobic silica (manufactured by Nippon Aerosil Co., Ltd., RY50) and 1.0 part by mass of hydrophobic titanium oxide (manufactured by Nippon Aerosil Co., Ltd., T805) using a sample mill at 10,000 rpm for 30 seconds, and then sieved using a vibrating sieve with 45 μm openings to prepare toner particles.

[0187] Example 30 Particles were prepared in the same manner as in Example 1, except that the amorphous polyester resin particle dispersion (A1) used in Example 1 was replaced with a styrene acrylic resin particle dispersion (SA1).

[0188] Example 31 Particles were prepared in the same manner as in Example 1, except that the amorphous polyester resin particle dispersion (A1) used in Example 1 was replaced with the styrene acrylic modified polyester resin particle dispersion (HB1).

[0189] <Comparative Example 1: Normal Toner> -Production of toner particles- Ion-exchanged water: 215 parts Amorphous polyester resin particle dispersion (A1): 127 parts Crystalline polyester resin particle dispersion (B1): 67 parts Release agent dispersion (W1): 40 parts Colorant dispersion: 20 parts Anionic surfactant (Dai-ichi Kogyo Seiyaku Co., Ltd.: Neogen RK, 20%): 2.8 parts The above components were placed in a 3-liter reaction vessel equipped with a thermometer, pH meter, and stirrer, and the temperature was controlled externally with a mantle heater while maintaining the temperature at 30°C and the stirring speed at 150 rpm for 30 minutes. Then, a 0.3N aqueous nitric acid solution was added to adjust the pH to 3.0 for the coagulation process.

[0190] While dispersing with a homogenizer (IKA Japan: Ultra Turrax T50), an aqueous PAC solution prepared by dissolving 0.7 parts of PAC (Oji Paper Co., Ltd.: 30% powder product) in 7 parts of ion-exchanged water was added. The mixture was then heated to 50°C while stirring, and the particle size was measured with a Coulter Multisizer II (aperture diameter: 50 μm, Coulter), revealing a volume average particle size of 4.9 μm. Subsequently, 100 parts of the amorphous polyester resin particle dispersion (A1) was added, and the amorphous polyester resin particles were adhered to the surfaces of the aggregated particles.

[0191] Next, 20 parts of a 10% NTA (nitrilotriacetic acid) metal salt aqueous solution (Chilest 70, manufactured by Chelest Corporation) was added, and the pH was adjusted to 9.0 with 1N sodium hydroxide solution. The mixture was then heated to 90°C at a rate of 0.05°C / min, held at 90°C for 3 hours, and then cooled to 30°C at a rate of 15°C / min. The mixture was then heated to 80°C, a temperature 5°C above the melting temperature of the crystalline resin, at a rate of 0.2°C / min, and held for 30 minutes. It was then rapidly cooled to 30°C at a rate of 15°C / min and filtered to obtain coarse toner particles. This was then redispersed in ion-exchange water and repeatedly filtered. The filtrate was washed until its electrical conductivity reached 20 μS / cm or less, and then vacuum-dried in a 40°C oven for 5 hours to obtain toner particles with a volume average particle size of 5.8 μm.

[0192] -Toner production- 100 parts of the obtained toner particles were mixed with 1.5 parts of hydrophobic silica (RY50, manufactured by Nippon Aerosil Co., Ltd.) using a sample mill at 10,000 rpm for 30 seconds, and then sieved using a vibrating sieve with 45 μm openings to obtain a toner.

[0193] <Comparative Example 2> 680 parts of amorphous polyester resin (A), 200 parts of crystalline polyester resin (B), 40 parts of carbon black (Regal 330), and 80 parts of ester wax (WEP-5) were thoroughly premixed in a Henschel mixer and melt-kneaded in a twin-screw roll mill. The melt-kneaded mixture was then discharged through a twin-screw extruder, and a sheet-like melt-kneaded product was produced using a rolling mill installed near the twin-screw extruder and cooled at 1°C / min. The sheet-like molten kneaded product was finely pulverized using a jet mill and further classified twice using an air classifier to obtain toner particles.

[0194] <Characteristics> The toner of each example was measured for the following properties according to the methods already described. Aspect ratio of the domain of the crystalline resin (referred to as aspect ratio AR in the table) The long axis length of the domain of the crystalline resin (long axis length L cry(denoted as) The long axis length of the crystalline resin domain relative to the maximum diameter of the toner particle (L cry (denoted as) The angle between the extension of the long axis of the crystalline resin domain and the tangent at the point where the extension touches the toner particle surface (in the table, the angle θ between the long axis and the tangent A (denoted as) The crossing angle of the extension lines of the long axes of the two crystalline resin domains (in the table, the crossing angle θ B (denoted as)

[0195] The shortest distance between the domain of the release agent present in the toner particle and the surface (i.e., the outer edge) of the toner particle (in the table, this is referred to as the shortest distance between the domain and the toner particle surface)

[0196] The ratio (number %) of first toner particles A that meet the following conditions to all toner particles Condition (A): The aspect ratio of the domain of the crystalline resin is 5 or more and 40 or less. Condition (B1): The length of the major axis of the domain of the crystalline resin is 0.5 μm or more and 1.5 μm or less. Condition (C): The angle formed by the extension of the long axis of the crystalline resin domain and the tangent at the point where the extension comes into contact with the surface of the toner particle is 60 degrees or more and 90 degrees or less. Condition (D): The crossing angle between the extensions of the long axes of the two crystalline resin domains is 45 degrees or more and 90 degrees or less.

[0197] The ratio (number %) of first toner particles A that further satisfies the following condition (E) to all toner particles Condition (E): The domain of the release agent is present at a depth of 50 nm or more from the surface of the toner particle.

[0198] The ratio (number %) of first toner particles B that meet the following conditions to all toner particles Condition (A'): The aspect ratio of the domain of the crystalline resin is 10 or more and 40 or less. Condition (B1'): The length of the major axis of the domain of the crystalline resin is 0.8 μm or more and 1.5 μm or less. Condition (C'): The angle formed by the extension of the long axis of the crystalline resin domain and the tangent at the point where the extension comes into contact with the surface of the toner particle is 75 degrees or more and 90 degrees or less. Condition (D'): The crossing angle between the extensions of the long axes of the two crystalline resin domains is 60 degrees or more and 90 degrees or less.

[0199] The proportion (number %) of first toner particles B that further satisfies the following condition (E) to all toner particles Condition (E): The domain of the release agent is present at a depth of 50 nm or more from the surface of the toner particle.

[0200] The ratio (number %) of second toner particles A that meet the following conditions to all toner particles Condition (A): The aspect ratio of the domain of the crystalline resin is 5 or more and 40 or less. Condition (B2): In at least one of the two domains of the crystalline resin, the ratio of the major axis length to the maximum diameter of the toner particle is 10% or more and 30% or less. Condition (C): The angle formed by the extension of the long axis of the crystalline resin domain and the tangent at the point where the extension comes into contact with the surface of the toner particle is 60 degrees or more and 90 degrees or less. Condition (D): The crossing angle between the extensions of the long axes of the two crystalline resin domains is 45 degrees or more and 90 degrees or less.

[0201] The proportion (number %) of second toner particles A that further satisfy the following condition (E) to all toner particles Condition (E): The domain of the release agent is present at a depth of 50 nm or more from the surface of the toner particle.

[0202] The ratio (number %) of second toner particles B that meet the following conditions to all toner particles Condition (A'): The aspect ratio of the domain of the crystalline resin is 10 or more and 40 or less. Condition (B2'): In at least one of the two domains of the crystalline resin, the ratio of the major axis length to the maximum diameter of the toner particle is 13% or more and 30% or less. Condition (C'): The angle formed by the extension of the long axis of the crystalline resin domain and the tangent at the point where the extension comes into contact with the surface of the toner particle is 75 degrees or more and 90 degrees or less. Condition (D'): The crossing angle between the extensions of the long axes of the two crystalline resin domains is 60 degrees or more and 90 degrees or less.

[0203] The proportion (number %) of second toner particles B that further satisfy the following condition (E) to all toner particles Condition (E): The domain of the release agent is present at a depth of 50 nm or more from the surface of the toner particle.

[0204] The morphology of domains A and B of the crystalline resin and domains of the release agent of a typical toner particle (hereinafter referred to as a typical toner) is shown in Table 2. Specifically, it is as follows. 100 toner particles of each example are observed, and among the 100 toner particles observed, the toner particle having the crystalline resin domain with the largest angle (condition (C)) between the extension line of the long axis of the crystalline resin domain and the tangent line at the point where the extension line touches the toner particle surface is designated as the representative toner particle. In the representative toner particle, the crystalline resin domain having the largest angle (condition (C)) between the extension of the long axis of the crystalline resin domain and the tangent at the point where the extension meets the toner particle surface is designated as crystalline resin domain A (see A in Figure 3), and the shape of crystalline resin domain A is shown in Table 2. In the representative toner particle, the crystalline resin domain having the largest crossing angle (condition (D)) with respect to the extension line of the long axis of the crystalline resin domain A is designated as the crystalline resin domain B (see B in Figure 3), and the shape of the crystalline resin domain B is shown in Table 2. Table 2 shows the crossing angle of the extension lines of the major axes of the crystalline resin domains A and B in the representative toner particles. Table 2 shows the domain morphology of the release agent in the representative toner particles.

[0205] <Evaluation> (Preparation of developer) Using the toners of each example, developers were obtained as follows. 500 parts of spherical magnetite powder particles (volume average particle diameter: 0.55 μm) were thoroughly stirred in a Henschel mixer, and then 5.0 parts of a titanate coupling agent were added, the temperature was raised to 100°C, and the mixture was mixed and stirred for 30 minutes to obtain spherical magnetite particles coated with a titanate coupling agent. Next, 6.25 parts of phenol, 9.25 parts of 35% formalin, 500 parts of the magnetite particles, 6.25 parts of 25% aqueous ammonia, and 425 parts of water were mixed and stirred in a four-neck flask. After reacting for 120 minutes at 85°C with stirring, the mixture was cooled to 25°C, 500 parts of water was added, the supernatant was removed, and the precipitate was washed with water. This was dried under reduced pressure at 150°C to 180°C to obtain a carrier with an average particle size of 35 μm. The toner of each example and the obtained carrier were then placed in a V blender at a mass ratio of toner:carrier=5:95, and stirred for 20 minutes to obtain a developer.

[0206] (uneven gloss) The resulting developer was used to evaluate uneven gloss as follows. The developers obtained in each example and comparative example were filled into the developing machine of an image forming apparatus "DocuCentrecolor 400 manufactured by Fuji Xerox Co., Ltd." Using this image forming apparatus, in an environment of a temperature of 28°C and a humidity of 85% RH, the Electrophotography Society of Japan Test Chart No. 5-1 was printed on OS coated paper (manufactured by Fujifilm Business Innovation Co., Ltd., basis weight 127 g / m) at a process speed of 228 mm / s. 2 Product name: OS coated paper W) with a toner mass (TMA) of 10.0 g / m2 in a solid image area with an image density of 100% 2 After that, the toner mass (TMA) in the solid image area with an image density of 100% was adjusted to 14.4 g / m 2The image was adjusted to the following: 1,000 sheets were printed on OS coated paper at a fixing temperature of 190° C. and a process speed of 90 m / s. The gloss of the black portion of Electrophotography Society Test Chart No. 5-1 when the first sheet of OS coated paper was printed and Electrophotography Society Test Chart No. 5-1 after 1,000 sheets were printed was measured by the following method. The gloss was measured at 60° at five locations using a portable gloss meter (BYK Gardner Micro Trigloss, manufactured by Toyo Seiki Seisakusho Co., Ltd.). The difference between the gloss measurements was determined and evaluated according to the following criteria. A: The difference between the maximum and minimum gloss values ​​of the output image on 1,001 sheets is less than 3° B: The difference between the maximum and minimum gloss values ​​of the output image on 1,001 sheets is less than 4° C: The difference between the maximum and minimum gloss values ​​of the output image on 1,001 sheets is less than 6° D: The difference between the maximum and minimum gloss values ​​of the output image on 1,001 sheets is less than 8° E: The difference between the maximum and minimum gloss values ​​of the output image on 1,001 sheets is less than 10° F: The difference between the maximum and minimum gloss values ​​of the output image on 1,001 sheets is 10° or more

[0207] [Table 1]

[0208] [Table 2]

[0209] [Table 3]

[0210] From the above results, it can be seen that the present embodiment suppresses the degree of uneven glossiness of an image that occurs when an image with a large amount of toner is formed, compared to the comparative example. [Explanation of symbols]

[0211] 1Y, 1M, 1C, 1K Photoconductor (an example of an image carrier) 2Y, 2M, 2C, 2K Charging roll (an example of charging means) 3. Exposure device (an example of an electrostatic image forming means) 3Y, 3M, 3C, 3K laser beam 4Y, 4M, 4C, 4K developing device (an example of developing means) 5Y, 5M, 5C, 5K Primary transfer roll (an example of a primary transfer means) 6Y, 6M, 6C, 6K: Photoconductor cleaning device (an example of a cleaning means) 8Y, 8M, 8C, 8K toner cartridges 10Y, 10M, 10C, 10K image forming units 20 Intermediate transfer belt (an example of an intermediate transfer body) 22 Drive Roll 24 Support Roll 26 Secondary transfer roll (an example of a secondary transfer means) 30 Intermediate transfer body cleaning device 107 Photosensitive body (an example of an image carrier) 108 Charging roll (an example of charging means) 109 Exposure device (an example of electrostatic image forming means) 111 Developing device (an example of developing means) 112 Transfer device (an example of transfer means) 113 Photosensitive drum cleaning device (an example of cleaning means) 115 Fixing device (an example of fixing means) 116 Mounting Rail 118 Exposure opening 117 Cabinet 200 Process Cartridge 300 Recording paper (an example of a recording medium) P Recording paper (an example of a recording medium)

Claims

1. The toner particles contain an amorphous resin and a crystalline resin, and when a cross section of the toner particle is observed, at least two domains of the crystalline resin satisfy the following conditions (A), (B1), (C), and (D): The toner for developing electrostatic images, wherein the content of the toner particles is 70% or more by number based on the total number of toner particles. Condition (A): The aspect ratio of the domain of the crystalline resin is 5 or more and 40 or less. Condition (B1): The length of the major axis of the domain of the crystalline resin is 0.5 μm or more and 1.5 μm or less. Condition (C): The angle formed by the extension of the long axis of the domain of the crystalline resin and the tangent at the point where the extension comes into contact with the surface of the toner particle is 60 degrees or more and 90 degrees or less. Condition (D): The crossing angle between the extensions of the long axes of the two domains of the crystalline resin is 45 degrees or more and 90 degrees or less.

2. The toner particles contain an amorphous resin and a crystalline resin, and when a cross section of the toner particle is observed, at least two domains of the crystalline resin satisfy the following conditions (A), (B2), (C), and (D): The toner for developing electrostatic images, wherein the content of the toner particles is 70% or more by number based on the total number of toner particles. Condition (A): The aspect ratio of the domain of the crystalline resin is 5 or more and 40 or less. Condition (B2): In at least one of the two domains of the crystalline resin, the ratio of the major axis length to the maximum diameter of the toner particle is 10% or more and 30% or less. Condition (C): The angle formed by the extension of the long axis of the domain of the crystalline resin and the tangent at the point where the extension comes into contact with the surface of the toner particle is 60 degrees or more and 90 degrees or less. Condition (D): The crossing angle between the extensions of the long axes of the two domains of the crystalline resin is 45 degrees or more and 90 degrees or less.

3. 3. The toner for developing electrostatic images according to claim 1, wherein the toner particles contain a release agent, and when a cross section of the toner particles is observed, a domain of the release agent is present at a depth of 50 nm or more from the surface of the toner particles.

4. 4. The toner for developing electrostatic images according to claim 3, wherein the release agent is an ester wax.

5. 5. The toner for developing electrostatic images according to claim 1, wherein the content of the toner particles is 80% or more by number of the total toner particles.

6. 6. An electrostatic image developer comprising the toner for developing electrostatic images according to claim 1.

7. A toner for developing electrostatic images according to any one of claims 1 to 5 is contained therein, A toner cartridge that is detachably attached to an image forming device.

8. a developing unit containing the electrostatic image developer according to claim 6 and developing an electrostatic image formed on the surface of an image carrier into a toner image by using the electrostatic image developer, A process cartridge is detachably mounted in an image forming apparatus.

9. an image carrier; a charging means for charging the surface of the image carrier; an electrostatic image forming means for forming an electrostatic image on the charged surface of the image carrier; The electrostatic image developer according to claim 6 is contained, and the electrostatic image developer is applied to the image carrier. a developing means for developing the electrostatic image formed on the surface of the image forming member into a toner image; a transfer means for transferring the toner image formed on the surface of the image carrier to the surface of a recording medium; a fixing means for fixing the toner image transferred onto the surface of the recording medium; An image forming apparatus comprising:

10. a charging step of charging the surface of the image carrier; an electrostatic image forming step of forming an electrostatic image on the charged surface of the image carrier; a developing step of developing the electrostatic image formed on the surface of the image carrier into a toner image by using the electrostatic image developer according to claim 6; a transfer step of transferring the toner image formed on the surface of the image carrier to the surface of a recording medium; a fixing step of fixing the toner image transferred onto the surface of the recording medium; An image forming method comprising the steps of:

Images