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

Abstract

To provide a toner for electrostatic charge image development that improves transferability to thick paper in a high temperature and high humidity environment.SOLUTION: A toner for electrostatic charge image development includes toner particles. The number average particle diameter of the toner for electrostatic charge image development is 5 μm or more and 8 μm or less. Of the toner for electrostatic charge image development with a particle diameter of 4.5 μm or less, the abundance of particles with a circularity of 0.96 or less is 10 number% or more and 40 number% or less.SELECTED DRAWING: None

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] Patent Document 1 discloses a developer containing a toner in which the proportion of particles having a circularity of 0.93 or less is 21% or less and which contains a binder resin, a colorant, and a non-heavy metal charge control agent, and a carrier. Patent Document 2 discloses a toner for electrostatic development that is characterized by containing a metal fluoride compound. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-221880 [Patent Document 2] Japanese Patent Application Publication No. 2-137855 Summary of the Invention [Problem to be solved by the invention]

[0004] The object of the present invention is to provide a toner for developing electrostatic images having a number average particle diameter of 5 μm or more and 8 μm or less, and which has improved transferability to cardboard in a high-temperature, high-humidity environment compared to a toner having a particle diameter of 4.5 μm or less, in which the proportion of particles having a circularity of 0.96 or less is less than 10% by number or more than 40% by number. [Means for solving the problem]

[0005] Means for solving the above problems include the following aspects. <1> A toner for developing electrostatic images, comprising toner particles, the number average particle diameter of the toner for developing electrostatic images is 5 μm or more and 8 μm or less, the proportion of particles having a circularity of 0.96 or less among the particles of the toner for developing electrostatic images having a particle size of 4.5 μm or less is 10% by number or more and 40% by number or less; Toner for developing electrostatic images. <2> The toner particles contain a halogen element. <1> 2. The toner for developing electrostatic images according to claim 1. <3> the amount of the halogen element present is 0.25 millimoles or more and 0.90 millimoles or less per 100 g of the toner for developing electrostatic images; <2> 2. The toner for developing electrostatic images according to claim 1. <4> The halogen element includes bromine. <2> or <3> 2. The toner for developing electrostatic images according to claim 1. <5> the amount of bromine present is 0.02% by mass or more and 0.07% by mass or less with respect to the entire toner for developing electrostatic images; <4> 2. The toner for developing electrostatic images according to claim 1. <6> The halogen element includes chlorine. <2> ~ <5> 10. The toner for developing electrostatic images according to claim 9, wherein the toner is a toner for developing electrostatic images. <7> the amount of chlorine present is 0.01% by mass or more and 0.03% by mass or less with respect to the entire toner for developing electrostatic images; <6> 2. The toner for developing electrostatic images according to claim 1. <8> the average circularity of the toner for developing electrostatic images is more than 0.96 and not more than 0.99; <1> ~ <7> 10. The toner for developing electrostatic images according to claim 9, wherein the toner is a toner for developing electrostatic images. <9> the proportion of particles having a circularity of 0.96 or less among the particles of the toner for developing electrostatic images having a particle size of more than 4.5 μm is 10% by number or more and 30% by number or less; <1> ~ <8> 10. The toner for developing electrostatic images according to claim 9, wherein the toner is a toner for developing electrostatic images. <10> the ratio of particles having a circularity of 0.96 or less among the particles of the toner for developing electrostatic images having a particle size of 4.5 μm or less is 0.6 to 2 times the ratio of particles having a circularity of 0.96 or less among the particles of the toner for developing electrostatic images having a particle size of more than 4.5 μm; <1> ~ <9> 10. The toner for developing electrostatic images according to claim 9, wherein the toner is a toner for developing electrostatic images. <11> <1> ~ <10> 10. An electrostatic image developer comprising the toner for developing electrostatic images according to any one of claims 1 to 9. <12> <1> ~ <10> 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. <13> <11> a developing device that contains the electrostatic image developer according to claim 1 and develops an electrostatic image formed on a 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. <14> an image carrier; a charging device that charges the surface of the image carrier; an electrostatic image forming device for forming an electrostatic image on the charged surface of the image carrier; <11> a developing device that contains the electrostatic image developer according to claim 1 and develops the electrostatic image formed on the surface of the image carrier into a toner image by using the electrostatic image developer; a transfer device that transfers the toner image formed on the surface of the image carrier to the surface of a recording medium; a fixing device for fixing the toner image transferred onto the surface of the recording medium; An image forming apparatus comprising: <15> 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; <11> 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]

[0006] <1> According to the invention, there is provided a toner for developing electrostatic images having a number average particle diameter of 5 μm or more and 8 μm or less, which has improved transferability to cardboard in a high-temperature, high-humidity environment compared to a toner for developing electrostatic images having a particle diameter of 4.5 μm or less, in which the proportion of particles having a circularity of 0.96 or less is less than 10% by number or more than 40% by number. <2> According to the invention, there is provided a toner for developing electrostatic images which has improved transferability to cardboard in a high-temperature, high-humidity environment compared to toner particles which do not contain a halogen element. <3> According to the invention, there is provided a toner for developing electrostatic images which has improved transferability to cardboard in a high-temperature, high-humidity environment compared to when the amount of halogen element present is less than 0.25 mmol or more than 0.90 mmol per 100 g of the toner for developing electrostatic images. <4> According to the invention, there is provided a toner for developing electrostatic images which has improved transferability to cardboard in a high-temperature, high-humidity environment compared to a toner containing only iodine as a halogen element. <5> According to the invention, a toner for developing electrostatic images is provided which has improved transferability to cardboard in a high-temperature, high-humidity environment compared to when the amount of bromine present is less than 0.02% by mass or more than 0.07% by mass of the entire toner for developing electrostatic images. <6> According to the invention, there is provided a toner for developing electrostatic images which has improved transferability to cardboard in a high-temperature, high-humidity environment compared to a toner containing only iodine as a halogen element. <7> According to the invention, a toner for developing electrostatic images is provided which has improved transferability to cardboard in a high-temperature, high-humidity environment compared to when the amount of chlorine present is less than 0.01% by mass or more than 0.03% by mass of the entire toner for developing electrostatic images. <8> According to the invention, there is provided a toner for developing electrostatic images that has improved transferability to cardboard in a high-temperature, high-humidity environment compared to toners for developing electrostatic images having an average circularity of 0.96 or less or exceeding 0.99. <9> According to the invention, there is provided a toner for developing electrostatic images which has improved transferability to cardboard in a high-temperature, high-humidity environment compared to a toner for developing electrostatic images having a particle diameter of more than 4.5 μm and in which the proportion of particles having a circularity of 0.96 or less is less than 10% by number or more than 30% by number. <10> According to the invention, there is provided a toner for developing electrostatic images which has improved transferability to cardboard in a high-temperature, high-humidity environment, compared to a case where the proportion of particles having a circularity of 0.96 or less among particles for developing electrostatic images which have a particle size of 4.5 μm or less is less than 0.6 times or more than 2 times the proportion of particles having a circularity of 0.96 or less among particles for developing electrostatic images which have a particle size of more than 4.5 μm. <11> , <12> , <13> , <14> , or <15> According to the invention, there is provided an electrostatic image developer, a toner cartridge, a process cartridge, an image forming apparatus, or an image forming method which has improved transferability to cardboard in a high-temperature, high-humidity environment compared to when an electrostatic image developing toner having a number average particle diameter of 5 μm or more and 8 μm or less, and in which the proportion of particles having a circularity of 0.96 or less among particles having a particle diameter of 4.5 μm or less is less than 10% by number or more than 40% by number. [Brief explanation of the drawings]

[0007] [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] 1 is a schematic diagram illustrating an example of a process cartridge that is detachably mounted to an image forming apparatus according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0008]

[0023] The following describes embodiments of the present disclosure. These descriptions and examples are intended to illustrate the embodiments and are not intended to limit the scope of the embodiments.

[0009] In the present disclosure, a numerical range indicated using "to" indicates a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively.

[0010] In the numerical ranges described in stages in this disclosure, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Furthermore, in the numerical ranges described in this disclosure, the upper or lower limit value of that numerical range may be replaced with a value shown in the examples.

[0011] In the present disclosure, 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.

[0012] When embodiments of the present disclosure are described with reference to the drawings, the configuration of the embodiment is not limited to the configuration shown in the drawings. Furthermore, the sizes of the components in each drawing are conceptual, and the relative size relationships between the components are not limited to these.

[0013] In the present disclosure, each component may contain multiple corresponding substances. When referring to the amount of each component in a composition in the present disclosure, if multiple substances corresponding to each component are present in the composition, the total amount of the multiple substances present in the composition is meant unless otherwise specified.

[0014] In the present disclosure, the composition may contain multiple types of particles corresponding to each component. When multiple types of particles corresponding to each component are present in the composition, the particle size of each component means the value for a mixture of the multiple types of particles present in the composition, unless otherwise specified.

[0015] In the present disclosure, "(meth)acrylic" means at least one of acrylic and methacrylic, and "(meth)acrylate" means at least one of acrylate and methacrylate.

[0016] [Electrostatic image developing toner] The toner for developing electrostatic images according to this embodiment (hereinafter simply referred to as "toner") contains toner particles, the number average particle diameter of the toner is 5 μm or more and 8 μm or less, and the proportion of particles having a circularity of 0.96 or less among the toner particles having a particle diameter of 4.5 μm or less is 10% by number or more and 40% by number or less. Hereinafter, toner particles having a particle size of 4.5 μm or less will be referred to as "small diameter particles," particles having a circularity of 0.96 or less will be referred to as "irregular shaped particles," and the proportion of irregular shaped particles in small diameter particles will be referred to as "small diameter irregular shaped proportion."

[0017] In this embodiment, by setting the small diameter irregularity ratio within the above range, the transferability to cardboard in a high temperature and high humidity environment (hereinafter also referred to as "high temperature and high humidity cardboard transferability") is improved. The reason for this is not clear, but is presumed to be as follows.

[0018] In forming an image using toner, for example, a toner image formed on the surface of an image carrier is transferred to an intermediate transfer member as needed, and then transferred to the surface of a recording medium. In conventional toners, small-diameter particles are nearly spherical and have a low proportion of small-diameter irregular particles, which means that the toner particles tend to be closely packed in the toner image before being transferred to the surface of the recording medium. When the toner particles are closely packed, there are many points where the toner particles come into contact with each other, making it easy for charge leakage paths to form between the contact points between the particles. Furthermore, when thick paper with a high basis weight, such as embossed paper, is used as the recording medium, the recording medium tends to retain moisture in a high-temperature, high-humidity environment. If charge leakage paths are formed, the charge in the toner will leak during transfer, which can easily reduce transfer efficiency.

[0019] In contrast, in this embodiment, the small diameter irregular shape ratio is 10% by number or more and 40% by number or less. When 10% or more of the small-diameter particles are irregular-shaped particles, the toner particles are less likely to be closely packed in the toner image, and charge leakage paths are less likely to occur. This is thought to suppress the decrease in transfer efficiency caused by charge leakage and improve transferability on high-temperature, high-humidity cardboard. In addition, in this embodiment, the transferability of thick paper under high temperature and humidity conditions is improved compared to when the proportion of small diameter irregular particles exceeds 40% by number. Among small diameter particles, irregular shaped particles tend to have a large contact area with the surface that the toner comes into contact with before the toner image is transferred to the surface of the recording medium (e.g., the surface of an image carrier or the surface of an intermediate transfer body), and are therefore likely to reduce transfer efficiency due to the influence of non-electrostatic adhesion. Particularly under high temperature and humidity conditions, electrostatic adhesion is reduced due to the tendency for charge leakage, and the influence of non-electrostatic adhesion becomes relatively greater. In this embodiment, it is estimated that by having the proportion of irregular shaped particles, which tend to have a large contact area with the surface, of the small diameter particles be 40% by number or less, the decrease in transfer efficiency due to non-electrostatic adhesion is suppressed, and the transferability of thick paper under high temperature and humidity conditions is improved. For the above reasons, it is presumed that the transferability to thick paper under high temperature and humidity conditions is improved in this embodiment.

[0020] <Toner particle size and circularity> Here, the particle size and circularity of the toner are measured using a flow particle image analyzer FPIA-3000 (manufactured by Sysmex Corporation). The number of toner samples is 4,500, the particle size measurement range is 0.5 μm to 200 μm, and the circularity measurement range is 0.200 to 1.000. The average circle-equivalent diameter in the projected image of the particle is defined as the toner particle size, and the number average of the particle sizes of 4,500 toner particles is defined as the number-average particle size of the toner. The circularity of the toner is calculated by (circular equivalent perimeter) / (perimeter), i.e., (perimeter of a circle with the same projected area as the projected image of the particle) / (perimeter of the projected image of the particle), and the number average of the circularities of 4,500 toner particles is defined as the average circularity of the toner. The proportion of particles in each particle size and circularity range is determined by distribution analysis of the measurement data. When the toner has an external additive attached to the surface of the toner particles, the particle size and circularity of the toner are values ​​measured for the toner having the external additive attached to the toner particles.

[0021] As mentioned above, the proportion of small diameter irregular particles is 10% by number or more and 40% by number or less, and from the viewpoint of improving transferability to high temperature and high humidity cardboard, it is preferably 15% by number or more and 35% by number or less, and more preferably 18% by number or more and 30% by number or less. The method for controlling the small diameter irregular particle ratio within the above range is not particularly limited. For example, when toner particles are produced by the aggregation-coalescence method described below, the small diameter irregular particle ratio may be controlled by adjusting the stirring speed in the aggregate particle formation step and the holding time in the fusion-coalescence step. Furthermore, the small diameter irregular particle ratio may be controlled by adding small diameter particles with adjusted circularity (for example, toner particles that are small diameter particles and irregular-shaped particles).

[0022] The proportion of particles having a circularity of 0.96 or less (i.e., irregularly shaped particles) among toner particles having a particle size of more than 4.5 μm (hereinafter also referred to as "large diameter particles") (hereinafter also referred to as "large diameter irregularly shaped particles proportion") is not particularly limited. From the viewpoint of improving transferability to high-temperature, high-humidity cardboard, the proportion of large diameter irregular particles is preferably 10% by number or more and 30% by number or less, more preferably 12% by number or more and 28% by number or less, and even more preferably 14% by number or more and 26% by number or less. The reason why the transferability of high-temperature, high-humidity cardboard improves when the large-diameter irregularity ratio is equal to or greater than the lower limit is presumed to be because the toner is less likely to be densely packed in the toner image, making it less likely that a charge leakage path will occur, thereby suppressing a decrease in transfer efficiency due to charge leakage.Furthermore, the reason why the transferability of high-temperature, high-humidity cardboard improves when the large-diameter irregularity ratio is equal to or less than the upper limit is presumed to be because the contact area between the toner and the surface of the member that it comes into contact with before the toner image is transferred to the surface of the recording medium is reduced, making it less susceptible to the effects of non-electrostatic adhesion. The method for controlling the ratio of large-diameter irregular particles to the above method is not particularly limited. For example, when toner particles are produced by the aggregation-coalescence method described later, the ratio of large-diameter irregular particles may be controlled by adjusting the stirring speed in the aggregate particle formation process and the holding time in the fusion-coalescence process, as in the case of the ratio of small-diameter irregular particles. In addition, the ratio of large-diameter irregular particles may be controlled by adding large-diameter particles with adjusted circularity.

[0023] From the viewpoint of improving transferability on high-temperature, high-humidity cardboard, the small diameter irregularity ratio is preferably 0.6 to 2 times the large diameter irregularity ratio, more preferably 0.7 to 1.9 times, and even more preferably 0.8 to 1.8 times. In other words, the ratio of the small diameter irregularity ratio to the large diameter irregularity ratio (small diameter irregularity ratio / large diameter irregularity ratio) is preferably 0.6 to 2, more preferably 0.7 to 1.9, and even more preferably 0.8 to 1.8. The reason why the transferability of high-temperature, high-humidity cardboard improves when the ratio (small diameter irregular particle ratio / large diameter irregular particle ratio) is equal to or greater than the above lower limit is presumably because the toner is less likely to be closely packed in the toner image, making it less likely that charge leakage paths will occur, thereby suppressing a decrease in transfer efficiency due to charge leakage.Furthermore, the reason why the transferability of high-temperature, high-humidity cardboard improves when the ratio (small diameter irregular particle ratio / large diameter irregular particle ratio) is equal to or less than the above upper limit is presumably because the contact area between the toner and the surface of the member that it comes into contact with before the toner image is transferred to the surface of the recording medium is reduced, making it less susceptible to the effects of non-electrostatic adhesion.

[0024] The number average particle diameter of the toner is 5 μm or more and 8 μm or less, and from the viewpoint of transferability, it is preferably 5.2 μm or more and 7.8 μm or less, and more preferably 5.4 μm or more and 7.6 μm or less. The proportion of small diameter particles in the entire toner is, for example, 10% by number or more and 38% by number or less, and from the viewpoint of transferability, 12% by number or more and 37% by number or less is preferable, and 15% by number or more and 36% by number or less is more preferable.

[0025] Furthermore, from the viewpoint of improving transferability on high-temperature, high-humidity cardboard, the average circularity of the toner is preferably greater than 0.96 and not greater than 0.99, more preferably 0.96 to 0.98, and even more preferably 0.96 to 0.97. It is presumed that the reason why transferability on high-temperature, high-humidity cardboard is improved when the average circularity of the toner is equal to or greater than the above-mentioned lower limit is that the contact area of ​​the toner with the surface of the member with which it comes into contact before the toner image is transferred to the recording medium surface is reduced, making it less susceptible to the effects of non-electrostatic adhesion. It is presumed that the reason why transferability on high-temperature, high-humidity cardboard is improved when the average circularity of the toner is equal to or less than the above-mentioned upper limit is that the toner is less likely to be closely packed in the toner image, making it less likely for charge leakage paths to occur, thereby relatively reducing the effects of non-electrostatic adhesion and suppressing a decrease in transfer efficiency caused by non-electrostatic adhesion.

[0026] <Halogen elements> In this embodiment, it is preferable that the toner particles contain a halogen element. When the number average particle diameter and the small diameter irregularity ratio of the toner are within the above ranges and the toner particles contain a halogen element, the transferability on thick paper at high temperature and high humidity is further improved. The reason why the inclusion of halogen elements in toner particles improves transferability on high-temperature, high-humidity cardboard is presumably because the presence of halogen elements increases the electron retention power of the toner particles, thereby suppressing a decrease in transfer efficiency due to charge leakage during transfer.

[0027] Examples of halogen elements include bromine, chlorine, iodine, and fluorine. The toner particles may contain only one halogen element or two or more halogen elements. From the viewpoint of improving electron retention, the toner particles preferably contain at least one of bromine and chlorine as the halogen element, and more preferably contain bromine. It is presumed that the toner particles containing at least one of bromine and chlorine have a greater effect of improving the electron retention of the toner particles than toner particles containing only iodine as the halogen element, and that the transferability on high-temperature, high-humidity cardboard is further improved. Furthermore, the toner particles containing at least one of bromine and chlorine are less likely to excessively increase the polarity of the toner than toner particles containing only fluorine as the halogen element. Furthermore, it is presumed that the charge leakage during transfer, which is likely to occur due to the attraction of moisture due to the high polarity of the toner, is suppressed, and that the transferability on high-temperature, high-humidity cardboard is further improved.

[0028] The amount of halogen element present per 100 g of toner (hereinafter also referred to as "halogen amount") is preferably 0.25 mmol or more and 0.90 mmol or less, more preferably 0.28 mmol or more and 0.85 mmol or less, and even more preferably 0.30 mmol or more and 0.80 mmol or less, from the viewpoint of improving transferability on high-temperature, high-humidity cardboard. The reason why the transferability to high-temperature, high-humidity cardboard improves when the halogen content is equal to or greater than the lower limit is presumably because the electron retention effect of the halogen element is more readily obtained than when the halogen content is less than the lower limit. Also, the reason why the transferability to high-temperature, high-humidity cardboard improves when the halogen content is equal to or less than the upper limit is presumably because the polarity of the toner is less likely to be excessively increased than when the halogen content exceeds the upper limit. When the toner particles contain two or more halogen elements, the halogen amount refers to the total amount of the two or more halogen elements contained in the toner particles.

[0029] The amount of bromine present in the entire toner (hereinafter also referred to as "bromine amount") is preferably 0.02% by mass or more and 0.07% by mass or less, more preferably 0.03% by mass or more and 0.07% by mass or less, and even more preferably 0.04% by mass or more and 0.06% by mass or less, from the viewpoint of improving transferability on high-temperature, high-humidity cardboard. When the amount of bromine is equal to or greater than the lower limit, the effect of improving the electron retention power of bromine is easily obtained, and when the amount of bromine is equal to or less than the upper limit, the polarity of the toner is less likely to be excessively increased, which is presumably why the transferability on thick paper at high temperatures and high humidity is improved.

[0030] The amount of chlorine present in the entire toner (hereinafter also referred to as "chlorine amount") is preferably 0.01% by mass or more and 0.03% by mass or less, more preferably 0.015% by mass or more and 0.03% by mass or less, and even more preferably 0.015% by mass or more and 0.025% by mass or less, from the viewpoint of improving transferability on high-temperature, high-humidity cardboard. When the amount of chlorine is equal to or greater than the lower limit, the effect of improving the electron retention power due to chlorine is easily obtained, and when the amount of chlorine is equal to or less than the upper limit, the polarity of the toner is less likely to be excessively increased, which is presumably why the transferability on thick paper at high temperatures and high humidity is improved.

[0031] The amount of each element present in the toner is determined by measurement using a fluorescent X-ray analyzer (ZSX Primus2 manufactured by Rigaku Co., Ltd.). The measurement sample is prepared by pressurizing 4 g of the toner to be measured in a pressure molding machine under conditions of 10 t and 1 minute, and molding into a disk shape of Φ50 mm. The measurement conditions are selected for each element based on the tube voltage, tube current, analyzing crystal, and slit specified for the device. The quantitative values ​​of the abundance of each element are determined by creating a calibration curve from the measurement values ​​of the calibration samples. For example, to measure the abundance of bromine, potassium bromide is thoroughly ground in an agate bowl, and toners are prepared by uniformly mixing three different mass ratios of potassium bromide to create the calibration samples. Then, using 4 g of each of these calibration samples, measurement samples are prepared using the method described above, and measurement is performed under the same conditions as the measurement samples for the toner to be measured, thereby obtaining a calibration curve of X-ray detection intensity and bromine content. Reference materials for measuring the abundance of bromine include, but are not limited to, salts such as potassium bromide and alkylammonium bromide, as well as reagents with specified purity.

[0032] As a method for controlling the amount of halogen in a toner, for example, a method of adding a compound containing a halogen element (hereinafter also referred to as a "halogen-containing compound") during the toner manufacturing process and adjusting the amount of the compound added can be mentioned. Among halogen-containing compounds, the amount of a compound containing bromine (hereinafter also referred to as a "bromine-containing compound") can be adjusted to control the amount of halogen and bromine. Similarly, among halogen-containing compounds, the amount of a compound containing chlorine (hereinafter also referred to as a "chlorine-containing compound") can be adjusted to control the amount of halogen and chlorine. Examples of the bromine-containing compound include ammonium salts such as dodecyltrimethylammonium bromide, benzyldodecyldimethylammonium bromide and ammonium bromide; and metal salts such as potassium bromide, aluminum bromide and magnesium bromide. Examples of the chlorine-containing compound include ammonium salts such as dodecyltrimethylammonium chloride, benzyldodecyldimethylammonium chloride, and ammonium chloride; and metal salts such as potassium chloride, aluminum chloride, and magnesium chloride. Examples of the iodine-containing compound include ammonium salts such as dodecyltrimethylammonium iodide, benzyldodecyldimethylammonium iodide, and ammonium iodide; and metal salts such as potassium iodide, aluminum iodide, and magnesium iodide. Examples of the fluorine-containing compound include metal salts such as sodium monofluorophosphate and sodium fluoride.

[0033] The toner according to this embodiment will be described in detail below.

[0034] The toner according to the present embodiment includes toner particles and may include an external additive.

[0035] (toner particles) The toner particles contain, for example, a resin, and may also contain a colorant, a release agent, and other additives.

[0036] -resin- Examples of the resin include vinyl resins made of homopolymers of monomers such as styrenes (e.g., styrene, parachlorostyrene, α-methylstyrene, etc.), (meth)acrylic acid esters (e.g., methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, etc.), ethylenically unsaturated nitriles (e.g., acrylonitrile, methacrylonitrile, etc.), vinyl ethers (e.g., vinyl methyl ether, vinyl isobutyl ether, etc.), vinyl ketones (vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone, etc.), and olefins (e.g., ethylene, propylene, butadiene, etc.), or copolymers of two or more of these monomers. Examples of the resin include non-vinyl resins such as epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, and modified rosin, mixtures of these with the vinyl resins, and graft polymers obtained by polymerizing vinyl monomers in the presence of these. These resins may be used alone or in combination of two or more.

[0037] The resin is preferably a polyester resin. Examples of polyester resins include known amorphous polyester resins. The polyester resin may be used in combination with a crystalline polyester resin. However, the content of the crystalline polyester resin is preferably in the range of 2% by mass to 40% by mass (preferably 2% by mass to 25% by mass) relative to the total resin.

[0038] The "crystalline" nature of a resin refers to the presence of a clear endothermic peak rather than a stepwise change in endothermic heat in differential scanning calorimetry (DSC). Specifically, this refers to the half-width of the endothermic peak being within 10°C when measured at a heating rate of 10°C / min. On the other hand, the term "amorphous" for a resin means that the half-width exceeds 10°C, that the endothermic amount exhibits a stepwise change, or that no clear endothermic peak is observed.

[0039] Amorphous polyester resin 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.

[0040] 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, orthophthalic 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.

[0041] 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.

[0042] The glass transition temperature (Tg) of the amorphous polyester 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."

[0043] The weight average molecular weight (Mw) of the amorphous polyester 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 polyester resin is preferably 2,000 or more and 100,000 or less. The molecular weight distribution Mw / Mn of the amorphous polyester 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.

[0044] 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.

[0045] Crystalline polyester resin 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.

[0046] 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.

[0047] 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.

[0048] Here, the polyhydric alcohol has an aliphatic diol content of 80 mol % or more, preferably 90 mol % or more.

[0049] The melting temperature of the crystalline polyester 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."

[0050] The weight average molecular weight (Mw) of the crystalline polyester resin is preferably 6,000 or more and 35,000 or less.

[0051] The crystalline polyester resin can be obtained by a known manufacturing method, for example, in the same manner as the amorphous polyester.

[0052] When the resin contains a polyester resin, the content of the polyester resin relative to the total resin is, for example, 20% by mass or more and 100% by mass or less, and preferably 40% by mass or more and 100% by mass or less.

[0053] Suitable resins also include vinyl-based resins. The vinyl resin will now be described. Examples of vinyl resins include homopolymers of monomers such as styrenes (e.g., styrene, parachlorostyrene, α-methylstyrene, etc.), (meth)acrylic acid esters (e.g., methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, etc.), ethylenically unsaturated nitriles (e.g., acrylonitrile, methacrylonitrile, etc.), vinyl ethers (e.g., vinyl methyl ether, vinyl isobutyl ether, etc.), vinyl ketones (e.g., vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone, etc.), and olefins (e.g., ethylene, propylene, butadiene, etc.), or vinyl resins made of copolymers of two or more of these monomers. These vinyl resins may be used alone or in combination of two or more.

[0054] As the vinyl resin, a styrene acrylic resin is preferred from the viewpoint of excellent environmental stability of toner charging. Styrene-acrylic resin is a copolymer 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)acryloyl group, preferably a monomer having a (meth)acryloyloxy group). Styrene-acrylic resin includes, for example, a copolymer of a styrene monomer and the above-mentioned (meth)acrylic acid ester monomer. The acrylic resin portion in the styrene-acrylic resin is either an acrylic monomer or a methacrylic monomer, or a partial structure obtained by polymerizing them. Furthermore, the term "(meth)acrylic" includes both "acrylic" and "methacrylic."

[0055] 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.

[0056] 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, from the viewpoint of improving the fixability of the toner, (meth)acrylic esters having an alkyl group having 2 to 14 carbon atoms (preferably 2 to 10 carbon atoms, more preferably 3 to 8 carbon atoms) are preferred. Among these, n-butyl (meth)acrylate is preferred, and n-butyl acrylate is particularly preferred.

[0057] 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 98 / 2 to 60 / 40.

[0058] The glass transition temperature (Tg) of the styrene acrylic resin is preferably 40° C. or more and 75° C. or less, and more preferably 50° C. or more and 65° C. or less, from the viewpoint of improving the fixability of the toner.

[0059] The glass transition temperature of the resin is determined from a DSC curve obtained by differential scanning calorimetry (DSC). More specifically, the glass transition temperature of the resin is determined by the "extrapolated glass transition onset temperature" described in JIS K 7121:1987 "Method for measuring the transition temperature of plastics."

[0060] From the viewpoint of storage stability of the toner, the weight average molecular weight of the styrene acrylic resin is preferably from 5,000 to 200,000, more preferably from 10,000 to 100,000, and particularly preferably from 20,000 to 80,000.

[0061] 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.).

[0062] The toner particles preferably contain at least one selected from the group consisting of polyester resin and vinyl resin, and may contain both a polyester resin and a vinyl resin, or only one of them. When the toner particles contain both a polyester resin and a vinyl resin, the toner particles may contain both a polyester resin and a vinyl resin as binder resins, or may contain one of a polyester resin and a vinyl resin as binder resin and the other as resin particles. When the toner particles contain one of a polyester resin and a vinyl resin as resin particles, the resin particles may have a crosslinked structure. When the toner particles contain both a polyester resin and a vinyl resin, the mass ratio C of the polyester resin to the vinyl resin is, for example, in the range of 0.7 or more and 10 or less, or may be 2 or more and 6 or less, or 3 or more and 5 or less.

[0063] An example of a resin containing both a polyester resin and a vinyl resin is a resin in which a styrene-acrylic resin and a polyester resin coexist. Here, the coexistence of styrene-acrylic resin and polyester resin can be achieved not only by mixing the respective resins, but also as a chemically bonded hybrid resin having a styrene-acrylic resin segment and a polyester resin segment (so-called styrene-acrylic modified polyester resin). Specifically, a hybrid resin can be obtained by polymerizing a polyester monomer having an unsaturated structure such as fumaric acid or succinic acid or a resin containing such a monomer structure as a prepolymer with a vinyl monomer such as styrene or acrylic. When a hybrid resin (a so-called styrene-acrylic modified polyester resin) is used, the mass ratio C of the polyester resin to the vinyl resin is measured and calculated as the mass ratio of the polyester segment to the vinyl resin segment (e.g., styrene-acrylic resin segment) of the hybrid resin. When a hybrid resin, a vinyl resin (e.g., styrene-acrylic resin), and a polyester resin are used in combination, the mass ratio C is measured and calculated as the mass ratio of the sum of the polyester resin segment and the polyester resin of the hybrid resin to the sum of the vinyl resin segment and the vinyl resin of the hybrid resin.

[0064] The resin content 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 88% by mass, based on the total mass of the toner particles.

[0065] -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 dyes 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.

[0066] 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.

[0067] The content of the colorant is, for example, preferably 1% by mass or more and 30% by mass or less, and more preferably 3% by mass or more and 15% by mass or less, based on the total mass of the toner particles.

[0068] -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. However, the release agent is not limited to these. Ester waxes and hydrocarbon waxes are preferred, and hydrocarbon waxes are more preferred.

[0069] 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 105°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."

[0070] The content of the release agent is, for example, preferably 1% by mass or more and 20% by mass or less, and more preferably 4% by mass or more and 15% by mass or less, based on the total mass of the toner particles.

[0071] -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.

[0072] -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.

[0073] (external additives) Examples of external additives include inorganic particles, such as SiO2, TiO2, Al2O3, SrTiO3, CuO, ZnO, SnO2, CeO2, Fe2O3, MgO, BaO, CaO, K2O, Na2O, ZrO2, CaO·SiO2, and K2O·(TiO2). n , Al2O3·2SiO2, CaCO3, MgCO3, BaSO4, MgSO4, etc.

[0074] 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.

[0075] 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).

[0076] The amount of the external additive added is, for example, preferably 0.01% by mass or more and 10% by mass or less, and more preferably 0.01% by mass or more and 6.0% by mass or less, based on the toner particles.

[0077] (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.

[0078] 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, it is preferable to obtain toner particles by the aggregation and coalescence method.

[0079] Specifically, for example, when toner particles are produced by the aggregation and coalescence method, for example, a step of mixing a first resin particle dispersion liquid in which first resin particles serving as a binder resin are dispersed, a colorant dispersion liquid in which a colorant is dispersed, and a release agent particle dispersion liquid in which particles of a release agent (hereinafter also referred to as "release agent particles") are dispersed, and aggregating the particles and the colorant in the obtained dispersion liquid to form first aggregated particles (first aggregated particle forming step); a step of adding second resin particles serving as a binder resin to the first aggregated particle dispersion liquid after obtaining the first aggregated particle dispersion liquid in which the first aggregated particles are dispersed, and aggregating the second resin particles onto the surfaces of the first aggregated particles to form second aggregated particles (second aggregated particle forming step); a step of heating the second aggregate particle dispersion liquid in which the second aggregate particles are dispersed to fuse and coalesce the second aggregate particles to form toner particles (fusion and coalescence step); Toner particles are produced through the above steps. The aggregation-coalescence method will be described as a method for producing toner particles containing a binder resin, a colorant, and a release agent, but the colorant and release agent are components that are contained in the toner particles as needed.

[0080] In the aggregation-coalescence method, the ratio of small diameter irregular particles and the ratio of large diameter irregular particles may be controlled by adjusting the stirring speed in the first aggregated particle formation step, which is part of the aggregated particle formation step, and the holding time in the fusion-coalescence step. The amount of halogen may be controlled by adding a halogen-containing compound and adjusting the amount added. When a halogen-containing compound is added to control the amount of halogen in the aggregation-coalescence method, the halogen-containing compound may be added, for example, after the second aggregated particle formation step and before the fusion-coalescence step. The timing of adding the halogen-containing compound is not limited thereto, and the halogen-containing compound may be added in the resin particle dispersion preparation step, the aggregated particle formation step, or the fusion-coalescence step.

[0081] Each step will be described in detail below.

[0082] -Each dispersion preparation process- First, the various dispersions to be used in the aggregation-coalescence method are prepared: a first resin particle dispersion in which first resin particles that will become the binder resin are dispersed, a colorant dispersion in which a colorant is dispersed, a second resin particle dispersion in which second resin particles that will become the binder resin are dispersed, and a release agent particle dispersion in which release agent particles are dispersed. In each dispersion preparation step, the first resin particles and the second resin particles will be referred to as "resin particles."

[0083] Here, the resin particle dispersion liquid is prepared, for example, by dispersing resin particles in a dispersion medium using a surfactant.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] Note that, for example, a colorant 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 dispersed in the colorant dispersion and the release agent particles dispersed in the release agent particle dispersion.

[0090] -First agglomerated particle formation process- Next, the first resin particle dispersion liquid, the colorant dispersion liquid, and the release agent particle dispersion liquid are mixed together. Then, in this mixed dispersion, the first resin particles, the colorant, and the release agent particles are hetero-aggregated to form first aggregated particles containing the first resin particles, the colorant, and the release agent particles.

[0091] Specifically, for example, an aggregating agent is added to a dispersion liquid obtained by mixing a first resin particle dispersion liquid, a colorant dispersion liquid, and a release agent particle dispersion liquid, and the pH of the mixed dispersion liquid 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.After that, the temperature is set to a range of 20°C or more and 50°C or less, and the particles dispersed in the mixed dispersion liquid 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.

[0092] The heating may be performed while stirring. The ratio of small-diameter irregular particles and the ratio of large-diameter irregular particles may be controlled by adjusting the stirring speed during heating (i.e., the stirring speed in the first aggregate particle formation step). Specifically, the ratio of small-diameter irregular particles and the ratio of large-diameter irregular particles are increased by slowing the stirring speed in the first aggregate particle formation step. Furthermore, the ratio of small-diameter irregular particles and the ratio of large-diameter irregular particles can also be increased by applying an intermittent cycle in the first aggregate particle formation step in which stirring is continued for a certain period of time and then stopped. In the first aggregate particle formation process, resin particles aggregate and become closer to spherical when heated while stirring. Lowering the stirring speed during heating makes it difficult for the first aggregate particles to incorporate fine particles, and the system as a whole becomes less uniform, broadening the particle size distribution and increasing the proportions of small and large irregular particles. Furthermore, applying an intermittent cycle increases the degree of non-uniformity when stirring is stopped. Small particles, which are particularly susceptible to physical stress, are less likely to become rounded, leaving unevenness and increasing the proportion of small and large irregular particles.

[0093] 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.

[0094] 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, relative to 100 parts by mass of the first resin particles.

[0095] -Second agglomerated particle formation process- Next, after obtaining the first aggregated particle dispersion liquid in which the first aggregated particles are dispersed, the second resin particle dispersion liquid in which the second resin particles are dispersed is added to the first aggregated particle dispersion liquid. The second resin particles may be of the same type as the first resin particles, or may be of a different type.

[0096] Then, in the dispersion of the first aggregated particles and the second resin particles, the second resin particles are aggregated on the surfaces of the first aggregated particles. At this time, a release agent particle dispersion may also be added to aggregate the second resin particles and the release agent particles on the surfaces of the first aggregated particles. Specifically, for example, in the first aggregated particle forming step, when the first aggregated particles reach a target particle size, the second resin particle dispersion is added to the first aggregated particle dispersion, and the mixture is heated at a temperature equal to or lower than the glass transition temperature of the second resin particles. Then, the pH of the dispersion is adjusted to, for example, a range of about 6.5 to 8.5, thereby stopping the progress of aggregation. In this manner, the second aggregated particles are obtained by aggregating the first aggregated particles so that the second resin particles adhere to the surfaces of the first aggregated particles.

[0097] After the second aggregate particle formation step, a halogen-containing compound may be added as needed before the fusion / coalescence step described below. The amount of halogen and the amount of each halogen element, such as bromine or chlorine, present in the toner may be controlled by adjusting the type and amount of the halogen-containing compound added. The halogen-containing compound may be added as it is or as an aqueous solution of the halogen-containing compound. When an aqueous solution of the halogen-containing compound is used, the concentration of the halogen-containing compound relative to the entire aqueous solution is not particularly limited, and may be, for example, in the range of 2% by mass to 8% by mass.

[0098] -Fusion / unification process- Next, the second aggregate particle dispersion liquid in which the second aggregate particles are dispersed is heated, for example, to a temperature equal to or higher than the glass transition temperature of the first and second resin particles (for example, a temperature 10 to 30°C higher than the glass transition temperature of the first and second resin particles) to fuse and coalesce the second aggregate particles and form toner particles.

[0099] In the fusion / coalescence process, the proportion of small-diameter irregular particles and the proportion of large-diameter irregular particles may be controlled by adjusting the time for which the resin particles are heated to a temperature above the glass transition temperature (hereinafter also referred to as the "fusion / coalescence time"). Specifically, the proportion of small-diameter irregular particles and the proportion of large-diameter irregular particles increase by shortening the fusion / coalescence time. During the fusion and coalescence process, maintaining the temperature above the glass transition temperature of the resin particles makes it easier for the resin to move, and it is thought that over time the toner particles become closer to spherical. Therefore, if the fusion and coalescence time is shortened, the toner particles tend to remain irregularly shaped, and the proportions of small and large irregular particles increase. The fusion / coalescence time may be, for example, in the range of 1 hour to 5 hours, and from the viewpoint of controlling the small diameter irregularity ratio within the above range, it is preferably in the range of 2 hours to 4 hours.

[0100] Through the above steps, toner particles are obtained. In the above-described aggregation and coalescence method, the first aggregated particles may be fused and coalesced to form toner particles without performing the second aggregated particle forming step. Also, the second aggregated particle forming step may be repeatedly performed multiple times.

[0101] 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.

[0102] 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.

[0103] <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 and a carrier mixed therewith.

[0104] 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.

[0105] Examples of magnetic powder include magnetic metals such as iron, nickel, and cobalt, and magnetic oxides such as ferrite and magnetite.

[0106] Examples of coating resins and matrix resins include styrene-(meth)acrylic acid resins; polyolefin resins such as polyethylene resins and polypropylene resins; polyvinyl or polyvinylidene resins such as polystyrene, (meth)acrylic resins, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether, and polyvinyl ketone; vinyl chloride-vinyl acetate copolymers; straight silicone resins or modified silicone resins consisting of organosiloxane bonds; fluororesins such as polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, and polychlorotrifluoroethylene; polyesters; polyurethanes; polycarbonates; amino resins such as urea-formaldehyde resins; and epoxy resins. The coating resin and the matrix resin preferably contain a (meth)acrylic resin, more preferably contain 50% by mass or more of the (meth)acrylic resin relative to the total mass of the resin, and even more preferably contain 80% by mass or more of the (meth)acrylic resin relative to the total mass of the resin. In particular, the coating resin and the matrix resin preferably contain an alicyclic (meth)acrylic resin as the (meth)acrylic resin. 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.

[0107] 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.

[0108] 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.

[0109] <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 device that charges the surface of the image carrier, an electrostatic image forming device that forms an electrostatic image on the surface of the charged image carrier, a developing device 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 device that transfers the toner image formed on the surface of the image carrier to the surface of a recording medium, and a fixing device 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.

[0110] 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.

[0111] 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 device that cleans the surface of the image carrier after the transfer of the toner image but before charging; and an apparatus equipped with a static elimination device that irradiates the surface of the image carrier with static elimination light to eliminate static after the transfer of the toner image but before charging. In the case of an intermediate transfer type device, the transfer device is configured to have, for example, an intermediate transfer body onto whose surface a toner image is transferred, a primary transfer device that performs primary transfer of the toner image formed on the surface of the image carrier onto the surface of the intermediate transfer body, and a secondary transfer device that performs secondary transfer of the toner image transferred onto the surface of the intermediate transfer body onto the surface of the recording medium.

[0112] In the image forming apparatus according to the present embodiment, for example, the portion including the developing device 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 a developing device that accommodates the electrostatic image developer according to the present embodiment is preferably used.

[0113] 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.

[0114] FIG. 1 is a schematic diagram showing the configuration of an image forming apparatus according to this embodiment. The image forming apparatus shown in Fig. 1 includes first through fourth electrophotographic image forming units 10Y, 10M, 10C, and 10K 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.

[0115] 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. Note that 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 outer circumferential surface of the intermediate transfer belt 20, facing the drive roll 22. In addition, the developing devices (examples of developing devices) 4Y, 4M, 4C, and 4K of each unit 10Y, 10M, 10C, and 10K are each supplied with toner including four colors of toner: yellow, magenta, cyan, and black, contained in toner cartridges 8Y, 8M, 8C, and 8K.

[0116] 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.

[0117] 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 device) 2Y that charges the surface of the photoreceptor 1Y to a predetermined potential; an exposure device (an example of an electrostatic image forming device) 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 device) 4Y that supplies charged toner to the electrostatic image to develop it; a primary transfer roll (an example of a primary transfer device) 5Y that transfers the developed toner image onto the intermediate transfer belt 20; and a photoreceptor cleaning device (an example of a cleaning device) 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).

[0118] 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 -6The 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.

[0119] 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 (developed) as a toner image by the developing device 4Y.

[0120] 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 stirring 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 with the yellow toner image formed thereon continues to travel at a predetermined speed, and the toner image developed on the photoreceptor 1Y is transported to a predetermined primary transfer position.

[0121] When the yellow toner image on the photoreceptor 1Y is transported to the primary transfer position, a primary transfer bias is applied to the primary transfer 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.

[0122] 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.

[0123] 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 made up 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 device) 26 arranged on the outer circumferential surface of the intermediate transfer belt 20. Meanwhile, recording paper (an example of a recording medium) P is fed via a feed 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 the resistance detected by a resistance detection device (not shown) that detects the resistance of the secondary transfer section, and is voltage-controlled.

[0124] 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 a fixing device) 28, where the toner image is fixed onto the recording paper P, forming a fixed image.

[0125] 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.

[0126] 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.

[0127] <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 device that develops an electrostatic image formed on the surface of an image carrier using the electrostatic image developer into a toner image.

[0128] 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 device selected from an image carrier, a charging device, an electrostatic image forming device, and a transfer device.

[0129] 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.

[0130] 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 device) provided around the photosensitive member 107, a developing device 111 (an example of a developing device), and a photosensitive member cleaning device 113 (an example of a cleaning device), which are held by a housing 117 having, for example, a mounting rail 116 and an opening 118 for exposure, and is formed into a cartridge. In FIG. 2, 109 denotes an exposure device (an example of an electrostatic image forming device), 112 denotes a transfer device (an example of a transfer device), 115 denotes a fixing device (an example of a fixing device), and 300 denotes recording paper (an example of a recording medium).

[0131] 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 device provided in the image forming apparatus.

[0132] 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]

[0133] Hereinafter, embodiments of the present invention will be described in detail with reference to examples, but the embodiments of the present invention are not limited to these examples. In the following description, unless otherwise specified, "parts" and "%" are based on mass.

[0134] <Preparation of various dispersions> (Preparation of amorphous polyester resin) First, in order to prepare an amorphous polyester resin, the following monomers were prepared. Bisphenol A ethylene oxide 2.2 mole adduct: 230 parts by weight Bisphenol A propylene oxide 2.2 mole adduct: 367 parts by mass Dimethyl terephthalate: 163 parts by mass Dimethyl fumarate: 12 parts by weight Dodecenyl succinic anhydride: 227 parts by mass Trimellitic anhydride: 20 parts by weight

[0135] Next, 2.2 moles of ethylene oxide adduct of bisphenol A, 2.2 moles of propylene oxide adduct of bisphenol A, dimethyl terephthalate, and dodecenylsuccinic anhydride were added to the vessel, and 2.55 parts by mass of tin dioctanoate was added. The added samples were then reacted for 6 hours at 235°C under a nitrogen gas flow, after which dimethyl fumarate and trimellitic anhydride were added and reacted for 1 hour at 200°C. The temperature was then raised to 220°C over 5 hours, and the monomers were polymerized under a pressure of 10 kPa to obtain a transparent, pale yellow amorphous polyester resin. The prepared amorphous polyester resin had a weight average molecular weight (Mw) of 35,000, a number average molecular weight (Mn) of 8,000, and a glass transition temperature (Tg) of 59°C.

[0136] (Preparation of Crystalline Polyester Resin) First, in order to prepare a crystalline polyester resin, the following monomers were prepared. 1,10-dodecanedioic acid: 225 parts by mass 1,6-Hexanediol: 118 parts by mass

[0137] Next, the two monomers were added to a vessel, the air in the vessel was replaced with dry nitrogen gas, and then 0.86 parts by mass of titanium tetrabutoxide was added. The mixture was then stirred at 170°C for 3 hours under a nitrogen gas flow. The temperature was then raised to 210°C over 1 hour, the pressure in the vessel was reduced to 3 kPa, and the mixture was stirred for 13 hours to obtain a crystalline polyester resin. The prepared crystalline polyester resin had a weight average molecular weight (Mw) of 25,000, a number average molecular weight (Mn) of 10,500, an acid value of 10.1 mgKOH / g, and a melting temperature of 73.6°C calculated by DSC.

[0138] (Preparation of amorphous polyester resin particle dispersion) 100 parts by mass of the above amorphous polyester resin was put into a disperser, which was a Cavitron CD1010 manufactured by Eurotec Co., Ltd., which had been modified to a high-temperature, high-pressure type. Next, ion-exchanged water was added until the mass percent concentration of the sample added to the disperser became 1 / 5, and the pH was adjusted to 8.5 using ammonia. The rotor rotation speed was set to 60 Hz and the pressure was set to 5 kg / cm. 2 The dispersion was prepared by operating the disperser at a temperature of 140°C. The volume average particle size of the resin particles in the prepared liquid was 130 nm. Ion-exchanged water was added to this prepared liquid to adjust the solid content to 20 mass %, thereby obtaining an amorphous polyester resin particle dispersion liquid in which amorphous polyester resin particles were dispersed.

[0139] (Preparation of Crystalline Polyester Resin Particle Dispersion) A crystalline polyester resin particle dispersion containing dispersed crystalline polyester resin particles was prepared in the same manner as in the preparation of the amorphous polyester resin particle dispersion, except that 100 parts by mass of crystalline polyester resin was used instead of the amorphous polyester resin. The volume average particle size of the resin particles in the resulting crystalline polyester resin particle dispersion was 130 nm, and the solid content was 20% by mass.

[0140] (Preparation of styrene acrylic resin particle dispersion) Styrene: 375 parts by weight n-Butyl acrylate: 25 parts by mass Acrylic acid: 2 parts by weight Dodecanethiol: 24 parts by mass ·Carbon tetrabromide: 4 parts by mass The mixture obtained by mixing and dissolving the above materials was dispersed and emulsified in a flask with a surfactant solution prepared by dissolving 6 parts by weight of a nonionic surfactant (Nonipol 400, manufactured by Sanyo Chemical Industries) and 10 parts by weight of an anionic surfactant (TaycaPower, manufactured by Tayca Corporation, 12% solids, sodium dodecylbenzenesulfonate) in 550 parts by weight of ion-exchanged water. Next, an aqueous solution prepared by dissolving 4 parts by weight of ammonium persulfate in 50 parts by weight of ion-exchanged water was added to the flask over a period of 20 minutes while stirring. After nitrogen substitution, the contents of the flask were heated in an oil bath with stirring until the temperature reached 70°C, and the temperature was maintained at 70°C for 5 hours to allow emulsion polymerization to continue. This resulted in a resin particle dispersion containing dispersed resin particles with a volume average particle size of 150 nm, a weight average molecular weight (Mw) of 33,000, and a glass transition temperature (Tg) of 63°C. Ion-exchanged water was added to this resin particle dispersion to adjust the solids content to 20% by weight, yielding a styrene-acrylic resin particle dispersion containing dispersed styrene-acrylic resin particles.

[0141] (Preparation of styrene acrylic modified polyester resin particle dispersion) 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 by weight of polyoxypropylene(2.2)-2,2-bis(4-hydroxyphenyl)propane, 585 parts by weight of polyoxyethylene(2.0)-2,2-bis(4-hydroxyphenyl)propane, 2,450 parts by weight of terephthalic acid, and 44 parts by weight 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 by weight of fumaric acid and 207 parts by weight 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 segment). Next, 800 parts by mass 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 a stirring speed of 200 rpm under a nitrogen atmosphere. After that, 100 parts by mass of styrene, 82 parts by mass of ethyl acrylate, 16 parts by mass of acrylic acid, 2 parts by mass of 1,10-decanediol diacrylate, and 1.00 parts by mass of toluene were added as addition polymerizable monomers, and the mixture was mixed for an additional 30 minutes. Furthermore, 6 parts by mass of polyoxyethylene alkyl ether (nonionic surfactant, trade name: Emulgen 430, manufactured by Kao Corporation), 40 parts by mass of 15% by mass aqueous solution of sodium dodecylbenzenesulfonate (anionic surfactant, trade name: Neopelex G-15, manufactured by Kao Corporation), and 233 parts by mass of 5% by mass potassium hydroxide were added, and the mixture was heated to 95°C while 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 by mass of deionized water was added dropwise at a rate of 6 parts by mass / min to obtain an emulsion. Next, the obtained emulsion was cooled to 25°C, passed through a 200-mesh wire screen, and deionized water was added to adjust the solid content to 20% by mass, thereby obtaining a styrene-acrylic-modified polyester resin particle dispersion in which styrene-acrylic-modified polyester resin particles were dispersed. The synthesized styrene-acrylic modified polyester resin had a mass ratio of styrene-acrylic resin segment to polyester resin segment (styrene-acrylic resin segment / polyester resin segment) of 20 / 80, a glass transition temperature (Tg) of 56°C, and a weight average molecular weight (Mw) of 33,000.

[0142] (Preparation of Black Pigment Dispersion) First, in order to prepare a black pigment dispersion, which is an example of a colorant particle dispersion, the following samples were prepared. Carbon black (Regal 330 manufactured by Cabot Corporation): 250 parts by weight Anionic surfactant (Neogen (registered trademark) SC manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 33 parts by mass Ion-exchanged water: 750 parts by weight

[0143] Next, 280 parts by weight of ion-exchanged water and 33 parts by weight of anionic surfactant were added to the container. After dissolving the surfactant, 250 parts by weight of carbon black (Regal 330) was added, and the mixture was stirred and degassed using a mixer until no unwetted pigment remained. After degassing, the remaining ion-exchanged water was added, and the mixture was stirred at 5000 rpm for 10 minutes using a homogenizer (Ultra-Turrax (registered trademark) T50 manufactured by IKA Japan Co., Ltd.) to disperse the carbon black (Regal 330), and then stirred and degassed for 1 day using a mixer. After degassing, the mixture was again stirred at 6000 rpm for 10 minutes using a homogenizer (Ultra-Turrax T50) to disperse the carbon black (Regal 330), and then stirred and degassed for 1 day using a mixer.

[0144] Next, carbon black (Regal 330) was dispersed at a pressure of 240 MPa using a high-pressure impact disperser, Ultimizer (HJP30006, manufactured by Sugino Machine Co., Ltd.) to obtain a mixed liquid. The resulting mixed liquid was left to stand for 72 hours to remove precipitate, and ion-exchanged water was added to obtain a black pigment dispersion adjusted to a solids concentration of 15% by mass. The volume average particle size of the particles in the obtained black pigment dispersion was 135 nm.

[0145] (Preparation of Release Agent Particle Dispersion) First, in order to prepare a release agent particle dispersion liquid, the following samples were prepared. Polyethylene wax (hydrocarbon wax, Baker Petrolite's Polywax (registered trademark) 725, melting temperature 104°C): 270 parts by mass Anionic surfactant (Neogen RK manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 13.5 parts by mass Ion-exchanged water: 21.6 parts by weight

[0146] Next, the above three samples were mixed, and a polyethylene wax (Polywax 725) was dissolved using a pressure discharge homogenizer (Gaulin Homogenizer manufactured by Gaulin Co., Ltd.), and the polyethylene wax (Polywax 725) was dispersed for 120 minutes at a pressure of 5 MPa, and then dispersed for 360 minutes at 40 MPa to obtain a mixed liquid. The obtained mixed liquid was cooled, and ion-exchanged water was added to obtain a release agent particle dispersion liquid adjusted to a solids concentration of 20.0 mass%. The volume average particle size of the particles in the resulting release agent particle dispersion was 225 nm.

[0147] (Preparation of aqueous halogen solution Br) 31 parts by mass of dodecyltrimethylammonium bromide (formula weight 308), which is a bromine-containing compound, and 500 parts by mass of ion-exchanged water were mixed and dissolved to prepare an aqueous halogen solution Br.

[0148] (Preparation of halogen aqueous solution Cl) 26 parts by mass of dodecyltrimethylammonium chloride (formula weight 263), which is a chlorine-containing compound, and 500 parts by mass of ion-exchanged water were mixed and dissolved to prepare an aqueous halogen solution Cl.

[0149] (Preparation of Aqueous Halogen Solution I) An aqueous halogen solution I was prepared by mixing and dissolving 36 parts by mass of dodecyltrimethylammonium iodide (formula weight: 355), an iodine-containing compound, and 500 parts by mass of ion-exchanged water.

[0150] <Toner Production> (Preparation of Toner 1) Amorphous polyester resin particle dispersion: 950 parts by weight Crystalline polyester resin particle dispersion: 300 parts by weight Black pigment dispersion: 160 parts by weight Release agent particle dispersion: 60 parts by weight Ion-exchanged water: 600 parts by weight Anionic surfactant (Dowfax® 2A1 manufactured by The Dow Chemical Company): 2.9 parts by weight The above components were placed in a 3-liter reaction vessel equipped with a thermometer, pH meter, and motor-driven stirring blade, and a heater bath was placed outside, and the temperature was adjusted with ice and a heater to maintain the temperature at 25°C. Next, 1.0% by mass of nitric acid was added to adjust the pH to 3.0, and then 130 parts by mass of an aqueous solution containing aluminum sulfate at a concentration of 2.0% by mass was added and dispersed for 6 minutes while dispersing at 5,000 rpm using a homogenizer (Ultra Turrax T50, manufactured by IKA Japan Co., Ltd.).

[0151] The stirring speed (i.e., the stirring speed in the first aggregate particle formation step) was then set to 60 rpm using the stirring blades provided in the reaction vessel instead of the homogenizer, and stirring was performed in an intermittent cycle of 9 minutes of stirring and 1 minute of stirring cessation. The temperature of the reaction vessel was raised at a rate of 0.2°C / min up to 40°C, and then at a rate of 0.05°C / min after exceeding 40°C. The particle size was measured every 10 minutes using a Multisizer II (aperture diameter: 50 μm, manufactured by Coulter). When the volume average particle size exceeded 5.0 μm, the temperature was maintained, and 50 parts by mass of the amorphous polyester resin dispersion was added over 5 minutes. The temperature was then adjusted to 50°C, and the mixture was maintained for 30 minutes while stirring at 60 rpm (second aggregate particle formation step).

[0152] After the second aggregate particle formation step was completed, the stirring blade speed was set to 100 rpm for continuous operation, and 50 parts by weight of a 10% by weight aqueous solution of the chelating agent Chelest 70 (manufactured by Chelest Corporation) was added dropwise. Then, 30 parts by weight of an aqueous halogen solution Br was added dropwise. The pH was adjusted to 9.0 using a 1.0% by weight aqueous sodium hydroxide solution. The temperature was then raised to 90°C at a rate of 1°C / min, while adjusting the pH to 9.0 every 5°C. While maintaining the temperature at 90°C, 10 g of 0.3 N nitric acid was added over 1 hour, and the mixture was maintained for 2 hours (i.e., the fusion and coalescence time was 2 hours). The liquid temperature was then cooled to 30°C over 20 minutes to obtain a toner slurry.

[0153] After cooling, the toner slurry was passed through a 15 μm nylon mesh to remove coarse particles and foreign matter. The passed toner slurry was then filtered under reduced pressure with an aspirator using a Nutsche with 5A filter paper. The toner cake remaining on the filter paper was removed from the bucket and its mass was measured. Ten times the mass of the toner cake was added to the 30°C ion-exchanged water, stirred for 30 minutes, and then similarly filtered using the Nutsche. The toner cake was then loosened and filtered using ten times the amount of ion-exchanged water, and this procedure was repeated three times for washing. The washed toner cake was then dried under reduced pressure at 30°C in a vacuum freeze dryer, removed, and thoroughly loosened with a spatula to obtain toner particles. To 100 parts by mass of the obtained toner particles, 1.5 parts by mass of hydrophobic silica (RY200S, manufactured by Nippon Aerosil Co., Ltd.) was added, and the mixture was mixed and blended using a sample mill at 13,000 rpm for 30 seconds. The mixture was then sieved using a vibrating sieve with 45 μm openings to obtain Toner 1.

[0154] (Production of Toners 2 to 11, 14 to 24, and C1 to C3) Toners 2 to 11, Toners 14 to 24, and Toners C1 to C3 were obtained in the same manner as Toner 1, except that the stirring speed in the first aggregate particle formation step ("Stirring speed (rpm)" in the table), whether or not an intermittent cycle of repeatedly stirring for 9 minutes and stopping stirring for 1 minute was applied in the first aggregate particle formation step ("Intermittent or continuous" in the table), the type and amount of the aqueous halogen solution added dropwise, and the fusion and coalescence time were set as shown in Table 1. In Table 1, "intermittent" means that an intermittent cycle of 9 minutes of stirring and 1 minute of stopping stirring was applied in the first flocculated particle formation step, "continuous" means that the first flocculated particle formation step was performed continuously without applying an intermittent cycle, and "-" means that the aqueous halogen solution was not added dropwise.

[0155] (Preparation of Toner 12) Amorphous polyester resin particle dispersion: 950 parts by weight Crystalline polyester resin particle dispersion: 50 parts by mass Styrene acrylic resin particle dispersion: 250 parts by weight Black pigment dispersion: 160 parts by weight Release agent particle dispersion: 60 parts by weight Ion-exchanged water: 600 parts by weight Anionic surfactant (Dowfax® 2A1 manufactured by The Dow Chemical Company): 2.9 parts by weight Toner 12 was obtained in the same manner as Toner 1, except that the components placed in a 3 liter reaction vessel equipped with a thermometer, a pH meter, and a motor-driven stirring blade were changed to the above components.

[0156] (Production of Toner 13) Crystalline polyester resin particle dispersion: 50 parts by weight Styrene acrylic modified polyester resin particle dispersion: 1200 parts by weight Black pigment dispersion: 160 parts by weight Release agent particle dispersion: 60 parts by weight Ion-exchanged water: 600 parts by weight Anionic surfactant (Dowfax® 2A1 manufactured by The Dow Chemical Company): 2.9 parts by weight Toner 13 was obtained in the same manner as Toner 1, except that the components placed in a 3-liter reaction vessel equipped with a thermometer, a pH meter, and a motor-driven stirring blade were changed to the above components, and the amorphous polyester resin dispersion liquid added in the second aggregate particle formation step was changed to a styrene-acrylic-modified polyester resin particle dispersion liquid.

[0157] <Measurement and Evaluation of Toner> The small diameter irregular particle ratio, large diameter irregular particle ratio, ratio (small diameter irregular particle ratio / large diameter irregular particle ratio) ("Ratio (small diameter / large diameter)" in the table), number average particle diameter, small diameter particle ratio, average circularity, halogen content, bromine content, and chlorine content of the obtained toner were determined using the methods described above, and the results are shown in Tables 2 to 4. In the table, "-" means that the corresponding halogen element is not contained.

[0158] (Preparation of developer) Each toner and a carrier obtained by the method described below were placed in a V blender at a mass ratio (toner / carrier) of 5 / 95 and stirred for 20 minutes to obtain each developer.

[0159] -Creating a carrier- A carrier was obtained by dispersing and mixing 100 parts by mass of ferrite cores with a volume average particle diameter of 35 μm, 2.0 parts by mass of cyclohexyl methacrylate resin (weight average molecular weight: 150,000), 0.6 parts by mass of carbon black (VXC72), and 0.3 parts by mass of melamine beads (Eposter S) in 10 parts by mass of toluene, and coating the mixture using a kneader.

[0160] (Evaluation of transferability) The evaluation printer used was a modified "700 Digital Color Press (manufactured by Fujifilm Business Innovation Co., Ltd.)." Each level of developer was filled into the developing unit, and transferability was evaluated. The paper (recording medium) was embossed cardboard (manufactured by Tokai Paper Co., Ltd., Lezac 66 white, basis weight 203.6 g / m 2 Embossed cardboard was left in a high-temperature, low-humidity environment (30°C, 20% RH) for 24 hours and then left in a high-temperature, high-humidity environment (30°C, 85% RH) for 48 hours, and then placed in a printer tray for use. The evaluation environment was a high temperature and humidity environment (30°C, 85% RH). 48 hours after the printer was installed, a 5 x 10 cm rectangular solid image was printed on the embossed cardboard with a toner loading of 5 g / m. 2 After adjusting and forming the image, an image quality evaluation (presence or absence of color loss due to poor transfer) was performed. The resulting image was visually inspected and the transferability grade was determined according to the following criteria. The results are shown in Tables 2 to 4.

[0161] -Evaluation criteria for transferability- A: No color loss is observed on the image on the embossed paper. B: There is a gap in the image on the embossed paper within 2% of the image area. C: Missing areas exist on the image on the embossed paper in the range of more than 2% but not more than 4% of the image area. D: Missing areas exist on the image on embossed paper in the range of more than 4% but not more than 6% of the image area. E: Missing areas exist on the image on the embossed paper in the range of more than 6% but not more than 8% of the image area. F: There is a gap in the image on embossed paper that is between 8% and 10% of the image area. G: There are gaps in the image on embossed paper that are between 10% and 12% of the image area. H: There is a gap in the image on embossed paper that is between 12% and 15% of the image area. I: There are gaps in the image on embossed paper that cover more than 15% of the image area.

[0162] [Table 1]

[0163] [Table 2]

[0164] [Table 3]

[0165] [Table 4]

[0166] From the above results, it can be seen that the present example has higher transferability on thick paper under high temperature and humidity conditions than the comparative example.

[0167] This embodiment includes the following aspects. (((1))) A toner for developing electrostatic images, comprising toner particles, the number average particle diameter of the toner for developing electrostatic images is 5 μm or more and 8 μm or less, the proportion of particles having a circularity of 0.96 or less among the particles of the toner for developing electrostatic images having a particle size of 4.5 μm or less is 10% by number or more and 40% by number or less; Toner for developing electrostatic images. (((2))) The toner for developing electrostatic images according to (((1))), wherein the toner particles contain a halogen element. (((3))) The electrostatic image developing toner according to (((2))), wherein the amount of the halogen element present is 0.25 millimoles or more and 0.90 millimoles or less per 100 g of the electrostatic image developing toner. (((4))) The toner for developing electrostatic images according to (((2))) or (((3))), wherein the halogen element includes bromine. (((5))) The toner for developing electrostatic images according to (((4))), wherein the amount of bromine present is 0.02% by mass or more and 0.07% by mass or less based on the total amount of the toner for developing electrostatic images. (((6))) The toner for developing electrostatic images according to any one of (((2))) to (((5))), wherein the halogen element includes chlorine. (((7))) The toner for developing electrostatic images according to (((6))), wherein the amount of chlorine present is 0.01% by mass or more and 0.03% by mass or less with respect to the entire toner for developing electrostatic images. (((8))) The toner for developing electrostatic images according to any one of (((1))) to (((7))), wherein the average circularity of the toner for developing electrostatic images is more than 0.96 and 0.99 or less. (((9))) The toner for developing electrostatic images according to any one of (((1))) to (((8))), wherein the proportion of particles having a circularity of 0.96 or less among the particles of the toner for developing electrostatic images having a particle size of more than 4.5 μm is 10% by number or more and 30% by number or less. (((10))) The electrostatic image developing toner according to any one of (((1))) to (((9))), wherein the proportion of particles having a circularity of 0.96 or less among the particles of the electrostatic image developing toner having a particle size of 4.5 μm or less is 0.6 to 2 times the proportion of particles having a circularity of 0.96 or less among the particles of the electrostatic image developing toner having a particle size of more than 4.5 μm. (((11))) An electrostatic image developer comprising the toner for developing electrostatic images according to any one of (((1))) to (((10))). (((12))) The toner for developing electrostatic images according to any one of (((1))) to (((10))) is contained, A toner cartridge that is detachably attached to an image forming device. (((13))) a developing device that contains the electrostatic image developer according to (((11))) and develops 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. (((14))) an image carrier; a charging device that charges the surface of the image carrier; an electrostatic image forming device for forming an electrostatic image on the charged surface of the image carrier; a developing device that contains the electrostatic image developer according to (((11))) and develops the electrostatic image formed on the surface of the image carrier into a toner image by using the electrostatic image developer; a transfer device that transfers the toner image formed on the surface of the image carrier to the surface of a recording medium; a fixing device for fixing the toner image transferred onto the surface of the recording medium; An image forming apparatus comprising: (((15))) 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 as a toner image using the electrostatic image developer according to (((11))); 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:

[0168] According to the invention related to (((1))), there is provided a toner for developing electrostatic images which has a number average particle diameter of 5 μm or more and 8 μm or less, and which has improved transferability to cardboard in a high-temperature, high-humidity environment compared to a toner having a particle diameter of 4.5 μm or less, in which the proportion of particles having a circularity of 0.96 or less is less than 10% by number or more than 40% by number. According to the invention related to (((2))), there is provided a toner for developing electrostatic images which has improved transferability to cardboard in a high-temperature, high-humidity environment compared to toner particles which do not contain a halogen element. According to the invention related to (((3))), there is provided a toner for developing electrostatic images which has improved transferability to cardboard in a high-temperature, high-humidity environment compared to when the amount of halogen element present is less than 0.25 mmol or more than 0.90 mmol per 100 g of the toner for developing electrostatic images. According to the invention related to (((4))), there is provided a toner for developing electrostatic images which has improved transferability to cardboard in a high-temperature, high-humidity environment compared to when the halogen element is only iodine. According to the invention related to (((5))), there is provided a toner for developing electrostatic images which has improved transferability to cardboard in a high-temperature, high-humidity environment compared to when the amount of bromine present is less than 0.02% by mass or more than 0.07% by mass of the entire toner for developing electrostatic images. According to the invention related to (((6))), there is provided a toner for developing electrostatic images which has improved transferability to cardboard in a high-temperature, high-humidity environment compared to when the halogen element is only iodine. According to the invention related to (((7))), there is provided a toner for developing electrostatic images which has improved transferability to cardboard in a high-temperature, high-humidity environment compared to when the amount of chlorine present is less than 0.01% by mass or more than 0.03% by mass of the entire toner for developing electrostatic images. According to the invention related to (((8))), there is provided a toner for developing electrostatic images which has improved transferability to cardboard in a high-temperature, high-humidity environment compared to toners for developing electrostatic images having an average circularity of 0.96 or less or exceeding 0.99. According to the invention related to (((9))), there is provided a toner for developing electrostatic images which has improved transferability to cardboard in a high-temperature, high-humidity environment, compared to a toner for developing electrostatic images having a particle diameter of more than 4.5 μm and in which the proportion of particles having a circularity of 0.96 or less is less than 10% by number or more than 30% by number. According to the invention related to (((10))), there is provided a toner for developing electrostatic images which has improved transferability to cardboard in a high-temperature, high-humidity environment, compared to a case where the proportion of particles having a circularity of 0.96 or less among particles for developing electrostatic images which have a particle size of 4.5 μm or less is less than 0.6 times or more than 2 times the proportion of particles having a circularity of 0.96 or less among particles for developing electrostatic images which have a particle size of more than 4.5 μm. According to the inventions of (((11))), (((12))), (((13))), (((14))), or (((15))), there is provided an electrostatic image developer, toner cartridge, process cartridge, image forming apparatus, or image forming method which has improved transferability to cardboard in a high-temperature, high-humidity environment compared to when an electrostatic image developing toner having a number average particle size of 5 μm or more and 8 μm or less and a particle size of 4.5 μm or less contains less than 10% by number or more than 40% by number of particles having a circularity of 0.96 or less. [Explanation of symbols]

[0169] 1Y, 1M, 1C, 1K Photoconductor (an example of an image carrier) 2Y, 2M, 2C, 2K Charging roll (example of charging device) 3. Exposure device (an example of an electrostatic image forming device) 3Y, 3M, 3C, 3K laser beam 4Y, 4M, 4C, 4K developing device (example of developing device) 5Y, 5M, 5C, 5K Primary transfer roll (an example of a primary transfer device) 6Y, 6M, 6C, 6K Photoconductor cleaning device (example of cleaning device) 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 device) 28 Fixing device (example of fixing device) 30 Intermediate transfer body cleaning device 107 Photosensitive body (an example of an image carrier) 108 Charging roll (an example of a charging device) 109 Exposure device (an example of an electrostatic image forming device) 111 Developing device (an example of a developing device) 112 Transcription device (an example of a transcription device) 113 Photosensitive drum cleaning device (an example of a cleaning device) 115 Fixing device (an example of a fixing device) 116 Mounting Rail 117 Cabinet 118 Exposure opening 200 Process Cartridge 300 Recording paper (an example of a recording medium) P Recording paper (an example of a recording medium)

Claims

1. A toner for developing electrostatic images, comprising toner particles, the number average particle diameter of the electrostatic image developing toner is 5 μm or more and 8 μm or less, the proportion of particles having a circularity of 0.96 or less among the particles of the toner for developing electrostatic images having a particle size of 4.5 μm or less is 10% by number or more and 40% by number or less; Toner for developing electrostatic images.

2. 2. The toner for developing electrostatic images according to claim 1, wherein the toner particles contain a halogen element.

3. 3. The toner for developing electrostatic images according to claim 2, wherein the amount of the halogen element present is 0.25 millimoles or more and 0.90 millimoles or less per 100 g of the toner for developing electrostatic images.

4. 3. The toner for developing electrostatic images according to claim 2, wherein said halogen element comprises bromine.

5. 5. The toner for developing electrostatic images according to claim 4, wherein the amount of bromine present is 0.02% by mass or more and 0.07% by mass or less based on the total amount of the toner for developing electrostatic images.

6. 3. The toner for developing electrostatic images according to claim 2, wherein said halogen element includes chlorine.

7. 7. The toner for developing electrostatic images according to claim 6, wherein the amount of chlorine present is 0.01% by mass or more and 0.03% by mass or less based on the total amount of the toner for developing electrostatic images.

8. 2. The toner for developing electrostatic images according to claim 1, wherein the average circularity of the toner for developing electrostatic images is more than 0.96 and not more than 0.

99.

9. 2. The toner for developing electrostatic images according to claim 1, wherein the proportion of particles having a circularity of 0.96 or less among particles having a particle size of more than 4.5 μm is 10% by number or more and 30% by number or less.

10. 2. The toner for developing electrostatic images according to claim 1, wherein the proportion of particles having a circularity of 0.96 or less among the particles of the toner for developing electrostatic images having a particle size of 4.5 μm or less is 0.6 to 2 times the proportion of particles having a circularity of 0.96 or less among the particles of the toner for developing electrostatic images having a particle size of more than 4.5 μm.

11. An electrostatic image developer comprising the toner for developing electrostatic images according to any one of claims 1 to 10.

12. A toner for developing electrostatic images according to any one of claims 1 to 10 is contained therein, A toner cartridge that is detachably attached to an image forming device.

13. a developing device containing the electrostatic image developer according to claim 11 and developing an electrostatic image formed on a 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.

14. an image carrier; a charging device that charges the surface of the image carrier; an electrostatic image forming device for forming an electrostatic image on the charged surface of the image carrier; a developing device containing the electrostatic image developer according to claim 11 and developing the electrostatic image formed on the surface of the image carrier into a toner image by the electrostatic image developer; a transfer device that transfers the toner image formed on the surface of the image carrier to the surface of a recording medium; a fixing device for fixing the toner image transferred onto the surface of the recording medium; An image forming apparatus comprising:

15. 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 11; 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