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

Abstract

The present invention relates to a toner for electrostatic image development, an electrostatic image developer, a toner cartridge, a process cartridge, an image forming apparatus and an image forming method. The toner for electrostatic image development comprises toner particles, layered structure compound particles and inorganic particles, wherein the free rate Fa of the layered structure compound particles released from the toner particles is 5% by volume or more and 20% by volume or less.

Description

Technical Field

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

[0002] Japanese Patent Application Laid-Open No. 2006-317489 discloses a toner in which 0.1 to 2.0 parts by weight of melamine cyanurate powder having a volume average particle size of 3 to 9 μm is added to a base toner having an average circularity of 0.94 to 0.995 and a volume average particle size of 3 to 9 μm based on 100 parts by weight of the base toner.

[0003] Japanese Patent Application Laid-Open No. 2009-237274 discloses a positively chargeable toner, wherein 0.01 to 0.5 parts by weight of melamine cyanurate particles having a number average primary particle size of 0.05 μm to 1.5 μm are added to colored resin particles containing a binder resin, a colorant, and a positive charge control agent, relative to 100 parts by weight of the colored resin particles. Summary of the invention

[0004] Technical problem to be solved by the invention

[0005] The technical problem to be solved by the present invention is to provide a toner for electrostatic image development. Compared with the toner for electrostatic image development which contains toner particles, layered structure compound particles and inorganic particles and in which the free rate Fa of layered structure compound particles released from the toner particles is less than 5 volume % or greater than 20 volume %, the toner for electrostatic image development of the present invention can inhibit the generation of color stripes (color bars) caused by the wear of the image retaining body cleaning scraper when low image density image formation is repeatedly performed under a high temperature and high humidity environment (temperature 30°C and relative humidity 85%), and can inhibit the generation of color stripes caused by poor cleaning of the intermediate transfer body when low image density image formation is repeatedly performed under a low temperature and low humidity environment (temperature 10°C and relative humidity 10%).

[0006] The technical problem to be solved by the present invention is to provide a toner for electrostatic image development. Compared with a toner for electrostatic image development which contains toner particles, layered structure compound particles and inorganic particles and whose number particle size distribution of the layered structure compound particles has no peak in the range of particle size of 0.1 μm to 1.5 μm or has no peak in the range of particle size of 3 μm to 80 μm, the toner for electrostatic image development of the present invention can inhibit the generation of color stripes caused by the wear of the image retaining body cleaning scraper when low image density image formation is repeatedly performed in a high temperature and high humidity environment (temperature of 30°C and relative humidity of 85%), and can inhibit the generation of color stripes caused by poor cleaning of the intermediate transfer body when low image density image formation is repeatedly performed in a low temperature and low humidity environment (temperature of 10°C and relative humidity of 10%).

[0007] Means for solving technical problems

[0008] According to a first aspect of the present invention, there is provided a toner for electrostatic image development, comprising toner particles, layered compound particles and inorganic particles, wherein the free rate Fa of the layered compound particles released from the toner particles is 5 volume % or more and 20 volume % or less.

[0009] According to the second scheme of the present invention, a toner for electrostatic image development is provided, which comprises toner particles, layered structure compound particles and inorganic particles, wherein the number particle size distribution of the layered structure compound particles has at least one peak in the range of particle diameter greater than 0.1 μm and less than 1.5 μm and has at least one peak in the range of particle diameter greater than 3 μm and less than 80 μm.

[0010] According to the third aspect of the present invention, the rate Fa of liberation of the layered structure compound particles liberated from the toner particles is 5 volume % or more and 20 volume % or less.

[0011] According to the fourth aspect of the present invention, the rate Fa of liberation of the layered structure compound particles liberated from the toner particles is 5% by volume or more and 10% by volume or less.

[0012] According to the fifth aspect of the present invention, a rate Fb of the inorganic particles released from the toner particles is not less than 10% by volume and not more than 30% by volume.

[0013] According to a sixth aspect of the present invention, the above-mentioned free rate Fb is not less than 10 volume % and not more than 20 volume %.

[0014] According to a seventh aspect of the present invention, a ratio Fa / Fb of the above-mentioned free rate Fa to the above-mentioned free rate Fb is 0.20 or more and 0.50 or less.

[0015] According to an eighth aspect of the present invention, a ratio Fa / Fb of the above-mentioned free rate Fa to the above-mentioned free rate Fb is 0.20 or less and 0.35 or less.

[0016] According to a ninth aspect of the present invention, the content of the layered structure compound particles is 0.02 mass % or more and 0.50 mass % or less based on the entire electrostatic image developing toner.

[0017] According to a tenth aspect of the present invention, the content of the inorganic particles is 1.0 mass % or more and 7.0 mass % or less based on the entire electrostatic image developing toner.

[0018] According to an eleventh aspect of the present invention, the layered compound particles include at least one selected from the group consisting of melamine cyanurate particles, boron nitride particles, graphite fluoride particles, molybdenum disulfide particles, and mica particles.

[0019] According to a twelfth aspect of the present invention, the inorganic particles include silica particles.

[0020] According to a thirteenth aspect of the present invention, there is provided an electrostatic image developer comprising the above-mentioned electrostatic image developing toner.

[0021] According to a fourteenth aspect of the present invention, there is provided a toner cartridge that is detachably mounted in an image forming apparatus and stores the above-mentioned toner for developing an electrostatic image.

[0022] According to a fifteenth aspect of the present invention, there is provided a process cartridge that is detachably mounted in an image forming apparatus, the process cartridge comprising:

[0023] Image holding body;

[0024] a developing mechanism storing the electrostatic image developer and developing the electrostatic image formed on the surface of the image holding member into a toner image using the electrostatic image developer;

[0025] an intermediate transfer body to which the toner image formed on the surface of the image holding body is transferred;

[0026] an image holding body cleaning mechanism having a scraper in contact with the surface of the image holding body, and using the scraper to clean the toner remaining on the surface of the image holding body after the toner image is transferred; and

[0027] The intermediate transfer body cleaning mechanism includes a scraper in contact with the surface of the intermediate transfer body, and uses the scraper to clean the toner remaining on the surface of the intermediate transfer body after the toner image is transferred to the surface of the recording medium.

[0028] According to a 16th aspect of the present invention, there is provided an image forming apparatus comprising:

[0029] Image holding body;

[0030] A charging mechanism for charging the surface of the image holding body;

[0031] An electrostatic image forming mechanism for forming an electrostatic image on the charged surface of the image holding member;

[0032] a developing mechanism storing the electrostatic image developer and developing the electrostatic image formed on the surface of the image holding member into a toner image using the electrostatic image developer;

[0033] an intermediate transfer body to which the toner image formed on the surface of the image holding body is transferred;

[0034] a primary transfer mechanism for transferring the toner image formed on the surface of the image holding body to the surface of the intermediate transfer body;

[0035] a secondary transfer mechanism that transfers the toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium;

[0036] a fixing mechanism for fixing the toner image transferred to the surface of the recording medium;

[0037] an image holding body cleaning mechanism having a scraper in contact with the surface of the image holding body, and using the scraper to clean the toner remaining on the surface of the image holding body after the toner image is transferred; and

[0038] The intermediate transfer body cleaning mechanism includes a scraper in contact with the surface of the intermediate transfer body, and uses the scraper to clean the toner remaining on the surface of the intermediate transfer body after the toner image is transferred to the surface of the recording medium.

[0039] According to a seventeenth aspect of the present invention, there is provided an image forming method comprising:

[0040] Charging, charging the surface of the image holding body;

[0041] Electrostatic image formation, forming an electrostatic image on the charged surface of the image holding member;

[0042] developing, using the electrostatic image developer to develop the electrostatic image formed on the surface of the image holding member into a toner image;

[0043] primary transfer, transferring the toner image formed on the surface of the image holding body to the surface of the intermediate transfer body;

[0044] Secondary transfer, transferring the toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium;

[0045] Fixing, fixing the toner image transferred to the surface of the recording medium;

[0046] cleaning the image holding body, bringing the scraper into contact with the surface of the image holding body after the toner image is transferred, and cleaning the toner remaining on the surface of the image holding body; and

[0047] The intermediate transfer body cleaning is performed by bringing a scraper into contact with the surface of the intermediate transfer body after the toner image is transferred to the surface of the recording medium, thereby cleaning the toner remaining on the surface of the intermediate transfer body.

[0048] Effects of the Invention

[0049] According to the above-mentioned schemes 1, 3, 9, 10, 11 or 12, a toner for electrostatic image development is provided. Compared with a toner for electrostatic image development containing toner particles, layered structure compound particles and inorganic particles and with a free rate Fa of layered structure compound particles released from the toner particles being less than 5 volume % or greater than 20 volume %, the toner for electrostatic image development of this scheme can suppress the generation of color stripes caused by the wear of the image retaining body cleaning scraper when low image density image formation is repeatedly performed under a high temperature and high humidity environment, and can suppress the generation of color stripes caused by poor cleaning of the intermediate transfer body when low image density image formation is repeatedly performed under a low temperature and low humidity environment.

[0050] According to the above-mentioned second scheme, a toner for electrostatic image development is provided. Compared with a toner for electrostatic image development that contains toner particles, layered structure compound particles and inorganic particles and the number particle size distribution of the layered structure compound particles has no peak in the range of particle diameters of not less than 0.1 μm and not more than 1.5 μm or has no peak in the range of particle diameters of not less than 3 μm and not more than 80 μm, the toner for electrostatic image development of this scheme can suppress the generation of color stripes caused by the wear of the image retaining body cleaning scraper when low image density image formation is repeatedly performed under a high temperature and high humidity environment, and can suppress the generation of color stripes caused by poor cleaning of the intermediate transfer body when low image density image formation is repeatedly performed under a low temperature and low humidity environment.

[0051] According to the fourth scheme, a toner for electrostatic image development is provided. Compared with the case where the free rate Fa of layered structure compound particles released from the toner particles is less than 5 volume % or greater than 10 volume %, the toner for electrostatic image development of this scheme can suppress the generation of color stripes caused by the wear of the image retaining body cleaning scraper when low image density image formation is repeatedly performed under a high temperature and high humidity environment, and can suppress the generation of color stripes caused by poor cleaning of the intermediate transfer body when low image density image formation is repeatedly performed under a low temperature and low humidity environment.

[0052] According to the fifth embodiment, a toner for electrostatic image development is provided, which can suppress the reduction in toner image transferability compared with the case where the free rate Fb of inorganic particles released from the toner particles is less than 10 volume % or greater than 30 volume %.

[0053] According to the sixth embodiment, a toner for electrostatic image development is provided, which can suppress the reduction in toner image transferability compared to the case where the free rate Fb of inorganic particles released from the toner particles is less than 10 volume % or greater than 20 volume %.

[0054] According to the seventh aspect, there is provided a toner for developing an electrostatic image, which can suppress a decrease in toner image transferability compared with a case where the ratio Fa / Fb of the free rate Fa to the free rate Fb is less than 0.20 or greater than 0.50.

[0055] According to the eighth aspect, there is provided a toner for developing an electrostatic image, which can suppress a decrease in toner image transferability compared with a case where the ratio Fa / Fb of the free rate Fa to the free rate Fb is less than 0.20 or greater than 0.35.

[0056] According to the above-mentioned scheme 13, an electrostatic image developer is provided. Compared with the case where the electrostatic image developing toner contains toner particles, layered structure compound particles and inorganic particles and the free rate Fa of the layered structure compound particles released from the toner particles is less than 5 volume % or greater than 20 volume %, the electrostatic image developer of this scheme can suppress the generation of color stripes caused by the wear of the image retaining body cleaning scraper when the low image density image formation is repeatedly performed under a high temperature and high humidity environment, and can suppress the generation of color stripes caused by poor cleaning of the intermediate transfer body when the low image density image formation is repeatedly performed under a low temperature and low humidity environment.

[0057] According to the above-mentioned 14th scheme, a toner box is provided. Compared with the case where the toner for electrostatic image development contains toner particles, layered structure compound particles and inorganic particles, and the free rate Fa of layered structure compound particles released from the toner particles is less than 5 volume % or greater than 20 volume %, the toner box of this scheme can suppress the generation of color stripes caused by the wear of the image retaining body cleaning scraper when low image density image formation is repeatedly performed under a high temperature and high humidity environment, and can suppress the generation of color stripes caused by poor cleaning of the intermediate transfer body when low image density image formation is repeatedly performed under a low temperature and low humidity environment.

[0058] According to the above-mentioned scheme 15, a processing box is provided. Compared with the case where the electrostatic image developing toner constituting the electrostatic image developer contains toner particles, layered structure compound particles and inorganic particles, and the free rate Fa of the layered structure compound particles released from the toner particles is less than 5 volume % or greater than 20 volume %, the processing box of this scheme can inhibit the formation of a coating on the surface of the image retaining body, inhibit the generation of color stripes caused by the wear of the image retaining body cleaning scraper when low image density image formation is repeatedly performed under a high temperature and high humidity environment, and inhibit the generation of color stripes caused by poor cleaning of the intermediate transfer body when low image density image formation is repeatedly performed under a low temperature and low humidity environment.

[0059] According to the above-mentioned 16th scheme, an image forming device is provided. Compared with the case where the electrostatic image developing toner constituting the electrostatic image developer contains toner particles, layered structure compound particles and inorganic particles, and the free rate Fa of the layered structure compound particles released from the toner particles is less than 5 volume % or greater than 20 volume %, the image forming device of this scheme can inhibit the formation of a coating on the surface of the image retaining body, inhibit the generation of color stripes caused by the wear of the image retaining body cleaning scraper when low image density image formation is repeatedly performed under a high temperature and high humidity environment, and inhibit the generation of color stripes caused by poor cleaning of the intermediate transfer body when low image density image formation is repeatedly performed under a low temperature and low humidity environment.

[0060] According to the above-mentioned 17th scheme, an image forming method is provided. Compared with the case where the electrostatic image developing toner constituting the electrostatic image developer contains toner particles, layered structure compound particles and inorganic particles, and the free rate Fa of the layered structure compound particles released from the toner particles is less than 5 volume % or greater than 20 volume %, the image forming method of this scheme can inhibit the formation of a coating on the surface of the image retaining body, inhibit the generation of color stripes caused by the wear of the image retaining body cleaning scraper when low image density image formation is repeatedly performed under a high temperature and high humidity environment, and inhibit the generation of color stripes caused by poor cleaning of the intermediate transfer body when low image density image formation is repeatedly performed under a low temperature and low humidity environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 This is a schematic structural diagram showing an example of the image forming apparatus according to the present embodiment.

[0062] Figure 2 This is a schematic structural diagram showing an example of a process cartridge that is attached to and detached from the image forming apparatus according to the present embodiment. DETAILED DESCRIPTION

[0063] The following is a description of embodiments of the present invention. These descriptions and examples are intended to illustrate the embodiments and are not intended to limit the scope of the embodiments.

[0064] In the present invention, the numerical range expressed using "to" means a range including the numerical values ​​described before and after "to" as the minimum value and the maximum value, respectively.

[0065] In the numerical range recorded in stages among the present invention, the upper limit or lower limit recorded in a numerical range can be replaced by the upper limit or lower limit of the numerical range in other stages recorded. In addition, in the numerical range recorded in the present invention, the upper limit or lower limit of this numerical range can be replaced by the value shown in the embodiment.

[0066] The term "step" in the present invention includes not only an independent step but also a step that cannot be clearly distinguished from other steps as long as the intended purpose of the step can be achieved.

[0067] When the embodiments of the present invention are described with reference to the drawings, the configuration of the embodiments is not limited to the configuration shown in the drawings. In addition, the sizes of the components in the drawings are schematic, and the relative relationship between the sizes of the components is not limited to this.

[0068] Each component in the present invention may contain two or more corresponding substances. When referring to the amount of each component in the composition of the present invention, if there are two or more substances corresponding to each component in the composition, unless otherwise stated, it refers to the total amount of the two or more substances present in the composition.

[0069] The particles corresponding to each component in the present invention may include two or more kinds of particles. When two or more kinds of particles corresponding to each component are present in the composition, unless otherwise stated, the particle size of each component refers to the value for the mixture of the two or more kinds of particles present in the composition.

[0070] In the present invention, “toner for developing an electrostatic image” is also simply referred to as “toner”, and “developer for developing an electrostatic image” is also simply referred to as “developer”.

[0071] <Toner for Electrostatic Image Development>

[0072] The present invention discloses a toner comprising toner particles, layered compound particles and inorganic particles, wherein the rate of release Fa of the layered compound particles released from the toner particles is 5% by volume or more and 20% by volume or less. This toner is referred to as "toner of the first embodiment".

[0073] The present invention discloses a toner, which comprises toner particles, layered structure compound particles and inorganic particles, wherein the number particle size distribution of the layered structure compound particles has at least one peak in the range of particle diameters of 0.1 μm to 1.5 μm and at least one peak in the range of particle diameters of 3 μm to 80 μm. This toner is referred to as a "toner of the second embodiment".

[0074] Hereinafter, when describing matters common to the toner according to the first embodiment and the toner according to the second embodiment, both toners are collectively referred to as “toner according to the present embodiment”.

[0075] In this embodiment, the free rate Fa of the layered compound particles released from the toner particles and the free rate Fb of the inorganic particles released from the toner particles are obtained based on the area ratio of the layered compound particles or the inorganic particles before and after the toner is treated with a surfactant. Specifically, they are obtained according to the following process (1) to (3).

[0076] (1) The toner is photographed using a scanning electron microscope (SEM), and the resulting SEM image is introduced into an image analysis device (e.g., NIRECO Co., Ltd., Luzex AP), and the total area A of the layered compound particles (or inorganic particles) and the total area B of the toner particles present in the image are calculated. The total area A is divided by the total area B and the resulting value is converted into a percentage (%), which is used as the area ratio P (P = A ÷ B × 100). The area ratio P refers to the area ratio of the layered compound particles (or inorganic particles) as a whole relative to the toner particles. The area ratio P of the layered compound particles is referred to as Pa, and the area ratio P of the inorganic particles is referred to as Pb.

[0077] (2) Add 2 g of the toner to 40 mL of a 0.2 mass % aqueous solution of the surfactant Triton X-100, and stir at a rotation speed of 500 rpm for 30 seconds using a magnetic stirrer and a stirring bar. Then centrifuge at a rotation speed of 10,000 rpm for 2 minutes in a centrifuge with a 50 mL sedimentation tube, and remove the supernatant. Add 40 mL of ion exchange water to the precipitate to disperse it, and centrifuge again at a rotation speed of 10,000 rpm for 2 minutes to remove the supernatant. Take the precipitate out of the sedimentation tube, spread it on filter paper, and dry it at room temperature (25°C) for 20 hours to obtain a powder sample. The powder sample is photographed using a scanning electron microscope, and the obtained SEM image is introduced into an image analysis device to calculate the total area A' of the layered structure compound particles (or inorganic particles) and the total area B' of the toner particles in the image. The total area A' is divided by the total area B' and the obtained value is converted into a percentage (%), which is used as the area ratio Q (Q = A' ÷ B' × 100). The area ratio Q refers to the area ratio of the layered structure compound particles (or inorganic particles) that are not free from the toner particles relative to the toner particles. The area ratio Q of the layered structure compound particles is called Qa, and the area ratio Q of the inorganic particles is called Qb.

[0078] (3) The free rate Fa is obtained from the area ratio Pa and area ratio Qa of the layered compound particles by the following formula. The free rate Fb is obtained from the area ratio Pb and area ratio Qb of the inorganic particles by the following formula.

[0079] Fa=(Pa-Qa)÷Pa×100

[0080] Fb=(Pb-Qb)÷Pb×100

[0081] In (1) and (2) above, a sufficient number of particles are observed, and the number is sufficient so that the area ratio can be approximated to the volume ratio. For the total area A, the total area B, the total area A' and the total area B', more than 1000 particles are observed respectively. The SEM images for analysis can also be multiple.

[0082] In the present embodiment, the number particle size distribution of the layered structure compound is determined by the following measurement method.

[0083] The toner is photographed using a scanning electron microscope, and the obtained SEM image is introduced into an image analysis device (e.g., NIRECO Co., Ltd., Luzex AP). 1000 layered structure compound particles present in the image are randomly selected without distinguishing whether they are primary particles or aggregated particles, and their equivalent circle diameters (nm) are calculated. When the layered structure compound particles are aggregated particles, one aggregate is counted as one layered structure compound particle, and the equivalent circle diameter of the aggregate is calculated. The number-based particle size distribution is obtained based on the equivalent circle diameters of 1000 particles.

[0084] The toner of this embodiment can suppress the generation of color streaks due to the wear of the image holder cleaning blade when low-image-density image formation is repeatedly performed under a high-temperature and high-humidity environment, and can suppress the generation of color streaks due to poor cleaning of the intermediate transfer body when low-image-density image formation is repeatedly performed under a low-temperature and low-humidity environment. The mechanism is presumed to be as follows.

[0085] In the past, toners with added layered compound particles (e.g., melamine cyanurate particles, boron nitride particles) were well known. Layered compound particles are particles of a compound having a layered structure with an interlayer distance of angstroms, and it is believed that they exhibit lubrication through interlayer slippage. The layered compound particles added to the toner act as a lubricant at the contact portion between the image holder and the image holder cleaning blade and at the contact portion between the intermediate transfer body and the intermediate transfer body cleaning blade.

[0086] Since the layered compound particles are relatively hygroscopic, they are not easily deteriorated even when image formation is performed in a high temperature and high humidity environment (e.g., a temperature of 30° C. and a relative humidity of 85%) (i.e., a voltage is applied to the layered compound particles on the image holder in a high temperature and high humidity environment), and the lubricating effect is easily sustained. However, when image formation with a low image density is repeatedly performed in a high temperature and high humidity environment, the supply of the layered compound particles to the image holder is delayed, and the lubricating effect of the layered compound particles is lost, which may cause color streaks (vertical streaks) caused by the wear of the image holder cleaning blade.

[0087] On the other hand, it can be inferred that when a toner having a free rate Fa of layered structure compound particles released from toner particles of 5% by volume or more is used, it is easy to supply layered structure compound particles from the toner to the image holder, the wear of the image holder cleaning blade is suppressed, and the color streaks caused by the wear of the image holder cleaning blade are suppressed. From this point of view, the free rate Fa is more preferably 6% by volume or more, and further preferably 7% by volume or more.

[0088] On the other hand, when the layered compound particles attached to the toner that remains without being transferred to the recording medium are supplied to the intermediate transfer body, if the supply amount is insufficient, color streaks (horizontal streaks) may occur due to poor cleaning of the intermediate transfer body. This phenomenon is significant when low-image density image formation is repeatedly performed in a low-temperature and low-humidity environment (e.g., a temperature of 10° C. and a relative humidity of 10%) (i.e., the layered compound particles are easily separated from the toner before reaching the intermediate transfer body, and the toner is supplied to the intermediate transfer body less).

[0089] On the other hand, it is presumed that when a toner having a free rate Fa of layered structure compound particles released from toner particles of 20% by volume or less is used, the layered structure compound particles are sufficiently contained in the toner reaching the intermediate transfer body, a sufficient amount of layered structure compound particles are supplied to the intermediate transfer body, and color streaks caused by poor cleaning of the intermediate transfer body are suppressed. From this point of view, the free rate Fa is more preferably 15% by volume or less, and further preferably 10% by volume or less.

[0090] In the toner of the second embodiment, the number particle size distribution of the layered structure compound particles has at least one peak (first peak) in the range of particle diameters of 0.1 μm to 1.5 μm and at least one peak (second peak) in the range of particle diameters of 3 μm to 80 μm, so that the morphology in which the liberation rate Fa is 5% by volume or more and 20% by volume or less can be easily achieved. It is presumed that this is because the layered structure compound particles constituting the first peak are relatively difficult to be liberated from the toner particles, and the layered structure compound particles constituting the second peak are relatively easy to be liberated from the toner particles.

[0091] The mass ratio (first / second) of the layered compound particles constituting the first peak to the layered compound particles constituting the second peak is preferably 1 to 10, more preferably 2 to 8, and even more preferably 3 to 7.

[0092] In the toner of the present embodiment, the free rate Fb of inorganic particles released from the toner particles is preferably 10% by volume or more and 30% by volume or less in order to suppress a decrease in toner image transferability during repeated image formation over a long period of time.

[0093] It is estimated that when the free rate Fb is 10% by volume or more and 30% by volume or less, a sufficient amount of inorganic particles can be supplied to the intermediate transfer body, a cleaning effect is exhibited on the surface of the intermediate transfer body, and excessive coating of the layered compound particles is suppressed.

[0094] The free rate Fb is more preferably 10% by volume to 25% by volume, and even more preferably 10% by volume to 20% by volume.

[0095] The above effect is remarkable when image formation is repeatedly performed on embossed paper in a low temperature and low humidity environment (eg, temperature 10° C. and relative humidity 15%).

[0096] From the viewpoint of suppressing a decrease in toner image transferability during long-term repeated image formation, the ratio Fa / Fb of the free rate Fa to the free rate Fb is preferably 0.20 to 0.50, more preferably 0.20 to 0.40, and even more preferably 0.20 to 0.35.

[0097] The above effect is remarkable when image formation is repeatedly performed on embossed paper in a low temperature and low humidity environment (eg, temperature 10° C. and relative humidity 15%).

[0098] The components, structure, and characteristics of the toner according to this embodiment are described in detail below.

[0099] [Toner particles]

[0100] The toner particles contain, for example, a binder resin and, if necessary, a colorant, a release agent, and other additives.

[0101] - Adhesive resin -

[0102] Examples of the adhesive resin include vinyl resins formed by homopolymers of the following monomers or copolymers of two or more of these monomers: styrenes (e.g., styrene, p-chlorostyrene, α-methylstyrene, etc.), (meth)acrylates (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.), olefins (e.g., ethylene, propylene, butadiene, etc.), and the like.

[0103] Examples of the adhesive resin include non-vinyl resins such as epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, and modified rosins, mixtures of these resins with the above-mentioned vinyl resins, or graft polymers obtained by polymerizing vinyl monomers in the coexistence of these resins.

[0104] These adhesive resins may be used alone or in combination of two or more.

[0105] As the adhesive resin, a polyester resin is suitable.

[0106] As the polyester resin, for example, a known amorphous polyester resin can be cited. Among the polyester resins, an amorphous polyester resin and a crystalline polyester resin can also be used together. Among them, it is preferable to use the crystalline polyester resin in a content of 2 mass % to 40 mass % (preferably 2 mass % to 20 mass %) relative to the total binder resin.

[0107] The "crystallinity" of a resin means that there is no step-like change in endothermic value in differential scanning calorimetry (DSC) and that the resin has a clear endothermic peak. Specifically, the half-width of the endothermic peak is within 10°C when measured at a heating rate of 10 (°C / min).

[0108] On the other hand, the "amorphous" nature of a resin means that the half-peak width is larger than 10°C, the endothermic quantity changes stepwise, or no clear endothermic peak is observed.

[0109] Amorphous polyester resin

[0110] Examples of the non-crystalline polyester resin include polycondensates of polycarboxylic acids and polyols. As the non-crystalline polyester resin, a commercially available product may be used, or a synthetic product may be used.

[0111] Examples of the polycarboxylic acid include aliphatic dicarboxylic acids (e.g., oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, alkenyl succinic acid, adipic acid, sebacic acid, etc.), alicyclic dicarboxylic acids (e.g., cyclohexane dicarboxylic acid, etc.), aromatic dicarboxylic acids (e.g., terephthalic acid, isophthalic acid, phthalic acid, naphthalene dicarboxylic acid, etc.), and anhydrides thereof or lower (e.g., carbon number 1 to 5) alkyl esters thereof. Among these, aromatic dicarboxylic acids are preferred as the polycarboxylic acid.

[0112] Among the polycarboxylic acids, dicarboxylic acids and trivalent or higher carboxylic acids having a crosslinked structure or a branched structure may be used in combination. Examples of the trivalent or higher carboxylic acids include trimellitic acid, pyromellitic acid, their anhydrides, or their lower (e.g., carbon number 1 to 5) alkyl esters.

[0113] The polyvalent carboxylic acid may be used alone or in combination of two or more.

[0114] Examples of the polyol 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, the polyol is preferably an aromatic diol or an alicyclic diol, and more preferably an aromatic diol.

[0115] As the polyol, a diol may be used in combination with a trivalent or higher polyol having a cross-linked structure or a branched structure. Examples of the trivalent or higher polyol include glycerin, trimethylolpropane, and pentaerythritol.

[0116] The polyols may be used alone or in combination of two or more.

[0117] The glass transition temperature (Tg) of the amorphous polyester resin is preferably 50°C to 80°C, and more preferably 50°C to 65°C.

[0118] The glass transition temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC), more specifically, by "extrapolated glass transition start temperature" described in the method for measuring glass transition temperature of JIS K7121:1987 "Method for measuring transition temperature of plastics".

[0119] The weight average molecular weight (Mw) of the amorphous polyester resin is preferably 5,000 to 1,000,000, and more preferably 7,000 to 500,000.

[0120] The number average molecular weight (Mn) of the amorphous polyester resin is preferably 2,000 or more and 100,000 or less.

[0121] 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.

[0122] The weight average molecular weight and the number average molecular weight were measured by gel permeation chromatography (GPC). In the molecular weight measurement using GPC, a Tosoh GPC HLC-8120GPC was used as a measuring device, a Tosoh column TSKgel SuperHM-M (15 cm) was used, and the measurement was performed using THF solvent. The weight average molecular weight and the number average molecular weight were calculated based on the measurement results using a molecular weight calibration curve prepared from a monodisperse polystyrene standard sample.

[0123] The amorphous polyester resin is obtained by a known production method. Specifically, for example, the amorphous polyester resin is obtained by setting the polymerization temperature to 180° C. to 230° C., reducing the pressure in the reaction system as necessary, and reacting while removing water or alcohol generated during condensation.

[0124] When the monomer of the raw material is insoluble or incompatible at the reaction temperature, a high boiling point solvent can be added as a dissolving aid to dissolve it. In this case, the polycondensation reaction is carried out while distilling off the dissolving aid. When there are monomers with poor compatibility in the copolymerization reaction, the monomers with poor compatibility can be condensed in advance with an acid or alcohol to be polycondensed with the monomer, and then polycondensed with the main component.

[0125] Crystalline polyester resin

[0126] Examples of the crystalline polyester resin include polycondensates of polycarboxylic acids and polyols. As the crystalline polyester resin, a commercially available product may be used, or a synthetic product may be used.

[0127] Here, in order to make the crystalline polyester resin easily form a crystal structure, the crystalline polyester resin is preferably a polycondensate obtained using a linear aliphatic polymerizable monomer rather than a polycondensate obtained using a polymerizable monomer having an aromatic ring.

[0128] Examples of the polycarboxylic acid include aliphatic dicarboxylic acids (e.g., oxalic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, etc.), aromatic dicarboxylic acids (e.g., dibasic acids such as phthalic acid, isophthalic acid, terephthalic acid, and naphthalene-2,6-dicarboxylic acid, etc.), their anhydrides, or their lower (e.g., carbon number 1 to 5) alkyl esters.

[0129] Among the polycarboxylic acids, dicarboxylic acids and trivalent or higher carboxylic acids having a cross-linked structure or a branched structure may be used in combination. Examples of trivalent carboxylic acids include aromatic carboxylic acids (e.g., 1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, etc.), their anhydrides, or their lower (e.g., carbon number 1 to 5) alkyl esters.

[0130] As the polycarboxylic acid, these dicarboxylic acids may be used in combination with a dicarboxylic acid having a sulfonic acid group or a dicarboxylic acid having an ethylenic double bond.

[0131] The polyvalent carboxylic acid may be used alone or in combination of two or more.

[0132] Examples of the polyol include aliphatic diols (e.g., linear aliphatic diols having a main chain portion having carbon atoms of 7 or more and 20 or less). Examples of the aliphatic diols include ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, and 1,14-eicosandiol. Among these, preferred aliphatic diols include 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol.

[0133] Among the polyols, diols may be used in combination with trivalent or higher alcohols having a cross-linked structure or a branched structure. Examples of the trivalent or higher alcohols include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol.

[0134] The polyols may be used alone or in combination of two or more.

[0135] Here, the content of the aliphatic diol in the polyol is preferably 80 mol % or more, and preferably 90 mol % or more.

[0136] The melting temperature of the crystalline polyester resin is preferably 50°C to 100°C, more preferably 55°C to 90°C, and even more preferably 60°C to 85°C.

[0137] The melting temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC) by the “melting peak temperature” described in the method for measuring the melting temperature of JIS K7121:1987 “Method for measuring transition temperatures of plastics”.

[0138] The weight average molecular weight (Mw) of the crystalline polyester resin is preferably 6,000 or more and 35,000 or less.

[0139] The crystalline polyester resin can be obtained, for example, by a known production method similar to the amorphous polyester.

[0140] The content of the binder resin is preferably 40% by mass to 95% by mass, more preferably 50% by mass to 90% by mass, and further preferably 60% by mass to 85% by mass, based on the entire toner particles.

[0141] -Colorants-

[0142] Examples of the colorant include carbon black, chrome yellow, Hansa yellow, benzidine yellow, vat yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, sulfur-resistant orange, Vochug red, permanent red, brilliant carmine 3B, brilliant carmine 6B, DuPont Oil Red, pyrazolone red, litho red, rhodamine B lake, lake red C, pigment red, rose red, aniline blue, ultramarine blue, oil-soluble blue, methylene blue chloride, phthalocyanine blue, pigment blue, phthalocyanine green, malachite green oxalate and other pigments; and dyes such as acridine, xanthene, azo, benzoquinone, azine, anthraquinone, thioindigo, dioxazine, thiazine, azomethine, indigo, phthalocyanine, nigrosine, polymethine, triphenylmethane, diphenylmethane and thiazole.

[0143] The coloring agent may be used alone or in combination of two or more.

[0144] The colorant may be a colorant that has been subjected to surface treatment as required, or may be used in combination with a dispersant. In addition, two or more colorants may be used in combination.

[0145] The content of the colorant is preferably from 1 mass % to 30 mass % both inclusive, and more preferably from 3 mass % to 15 mass % both inclusive, based on the entire toner particles.

[0146] -Release agent-

[0147] Examples of the release agent include hydrocarbon waxes, natural waxes such as carnauba wax, rice wax, and candelilla wax, synthetic waxes such as montan wax, or mineral and petroleum waxes, and ester waxes such as fatty acid esters and montanic acid esters. The release agent is not limited thereto.

[0148] The melting temperature of the release agent is preferably 50°C to 110°C, more preferably 60°C to 100°C.

[0149] The melting temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC) by the “melting peak temperature” described in the method for measuring the melting temperature of JIS K7121:1987 “Method for measuring transition temperatures of plastics”.

[0150] The content of the release agent is preferably from 1 mass % to 20 mass % both inclusive, and more preferably from 5 mass % to 15 mass % both inclusive, based on the entire toner particles.

[0151] -Other additives-

[0152] Examples of other additives include known additives such as magnetic materials, charge control agents, and inorganic powders. These additives may be contained in the toner particles as internal additives.

[0153] -Characteristics of toner particles, etc.-

[0154] 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 portion (core particle) and a coating layer (shell layer) that covers the core portion.

[0155] The toner particles of a core-shell structure may be composed of, for example, a core portion including a binder resin and, if necessary, other additives such as a colorant and a release agent, and a coating layer including a binder resin.

[0156] The volume average particle diameter (D50v) of the toner particles is preferably from 2 μm to 10 μm, and more preferably from 4 μm to 8 μm.

[0157] The volume average particle size (D50v) of the toner particles is measured using Coulter Multisizer II (manufactured by Beckman Coulter) and the electrolyte is measured using ISOTON-II (manufactured by Beckman Coulter).

[0158] In the measurement, 0.5 mg to 50 mg of the measurement sample is added to 2 ml of a 5 mass % aqueous solution of a surfactant (preferably sodium alkylbenzene sulfonate) as a dispersant, and then added to 100 ml to 150 ml of the electrolyte.

[0159] The electrolyte in which the sample is suspended is dispersed for 1 minute using an ultrasonic disperser, and the particle size distribution of particles with a particle size of 2 μm or more and 60 μm or less is measured using a Coulter Multisizer II with a hole of 100 μm in diameter. The number of particles sampled is 50,000. The volume-based particle size distribution is drawn from the small diameter side, and the particle size at the cumulative 50% point is taken as the volume average particle size D50v.

[0160] The average circularity of the toner particles is preferably from 0.94 to 1.00, and more preferably from 0.95 to 0.98.

[0161] The average circularity of the toner particles is determined by (equivalent circular circumference) / (circumference) [(circumference of a circle having the same projected area as the particle image) / (circumference of the particle projected image)]. Specifically, it is a value measured by the following method.

[0162] First, the toner particles to be measured are collected by suction and formed into a flat flow, and the particles are momentarily strobed to obtain a particle image as a still image, and the particle image is analyzed by a flow particle image analyzer (FPIA-3000 manufactured by Sysmex) to obtain the average circularity. The number of samples for obtaining the average circularity is set to 3500.

[0163] When the toner has an external additive, the toner (developer) to be measured is dispersed in water containing a surfactant and then subjected to ultrasonic treatment to obtain toner particles from which the external additive has been removed.

[0164] [Layered compound particles]

[0165] The layered compound particles are particles of a compound having a layered structure. Examples of the layered compound particles include melamine cyanurate particles, boron nitride particles, graphite fluoride particles, molybdenum disulfide particles, and mica particles.

[0166] From the perspective of controlling the free rate Fa within the range of 5 volume % to 20 volume %, the number particle size distribution of the layered structure compound particles preferably has at least one peak in the range of particle size of 0.1 μm to 1.5 μm (first range) and at least one peak in the range of particle size of 3 μm to 80 μm (second range).

[0167] The first range is more preferably 0.2 μm to 1.2 μm, and even more preferably 0.3 μm to 1.0 μm.

[0168] The second range is more preferably 8 μm to 50 μm, and even more preferably 10 μm to 35 μm.

[0169] The number particle size distribution of the layered compound particles can be controlled by combining two or more layered compound particles having different particle sizes. The particle size of the layered compound particles can be controlled by pulverization, classification, or a combination of pulverization and classification.

[0170] The number average particle size of the layered compound particles (particle size at 50% cumulative points from the smaller diameter side of the number particle size distribution) is preferably 0.2 μm to 5.0 μm, more preferably 0.3 μm to 3.0 μm, and even more preferably 0.3 μm to 2.0 μm.

[0171] From the perspective of obtaining the lubricating effect of the layered structure compound particles, the content of the layered structure compound particles is preferably 0.02% by mass or more, more preferably 0.03% by mass or more, and further preferably 0.05% by mass or more relative to the entire toner. From the perspective of suppressing excessive aggregation of the layered structure compound particles, the content of the layered structure compound particles is preferably 0.50% by mass or less, more preferably 0.30% by mass or less, and further preferably 0.20% by mass or less relative to the entire toner.

[0172] [Inorganic particles]

[0173] Examples of inorganic particles include SiO2, TiO2, Al2O3, CuO, ZnO, SnO2, CeO2, Fe2O3, MgO, BaO, CaO, K2O, Na2O, ZrO2, CaO·SiO2, K2O·(TiO2) n , Al2O3·2SiO2, CaCO3, MgCO3, BaSO4, MgSO4, etc.

[0174] The surface of inorganic particles can be subjected to hydrophobic treatment. As hydrophobic treatment agent, for example, known organosilicon compounds with alkyl (such as methyl, ethyl, propyl, butyl, etc.) can be enumerated, and specific examples can enumerate alkoxysilane compounds, siloxane compounds, silazane compounds, etc. Among these, hydrophobic treatment agent is preferably silazane compound, more preferably hexamethyldisilazane. Hydrophobic treatment agent can be used alone or in combination of two or more.

[0175] As a method for hydrophobizing inorganic particles using a hydrophobizing agent, for example, there can be mentioned: a method of dissolving the hydrophobizing agent in supercritical carbon dioxide using supercritical carbon dioxide, so that the hydrophobizing agent adheres to the surface of the inorganic particles; a method of imparting (for example, spraying or coating) a solution containing a hydrophobizing agent and a solvent that dissolves the above-mentioned hydrophobizing agent to the surface of the inorganic particles in the atmosphere, so that the hydrophobizing agent adheres to the surface of the inorganic particles; a method of adding a solution containing a hydrophobizing agent and a solvent that dissolves the above-mentioned hydrophobizing agent to an inorganic particle dispersion in the atmosphere and maintaining it, and then drying a mixed solution of the inorganic particle dispersion and the above-mentioned solution.

[0176] From the perspective of controlling the free rate Fb within the range of 10% by volume to 30% by volume, the number average particle size of the inorganic particles (preferably silica particles) is preferably 40nm to 200nm, more preferably 50nm to 180nm, and further preferably 60nm to 160nm.

[0177] From the perspective of controlling the free rate Fb within the range of greater than 10 volume % and less than 30 volume %, the number particle size distribution of inorganic particles (preferably silica particles) preferably has at least one peak in the range of particle diameter greater than 40 nm and less than 80 nm (first range) and has at least one peak in the range of particle diameter greater than 80 nm and less than 200 nm (second range).

[0178] The first range is more preferably 40 nm to 70 nm, and even more preferably 40 nm to 60 nm.

[0179] The second range is more preferably from 90 nm to 180 nm, and even more preferably from 100 nm to 160 nm.

[0180] The number average particle size of the inorganic particles is determined by the following measurement method.

[0181] First, inorganic particles are separated from the toner. There is no limitation on the method for separating inorganic particles from the toner. For example, the toner is dispersed in water containing a surfactant and ultrasonic waves are applied to the obtained dispersion. The dispersion is then centrifuged at high speed to centrifuge the toner particles, inorganic particles, and other external additives according to their specific gravity. The fraction containing the inorganic particles is extracted and dried to obtain the inorganic particles.

[0182] Next, the inorganic particles are added to the electrolyte aqueous solution and ultrasonic waves are applied for more than 30 seconds to disperse them. The dispersion is used as a sample, and the particle size is measured using a laser diffraction scattering particle size distribution measuring device (e.g., Microtrac BEL, Microtrac MT3000II). At least 3000 inorganic particles are measured to obtain a number-based particle size distribution. The particle size at the cumulative 50% point from the small particle size side in the number particle size distribution is taken as the number average particle size.

[0183] From the perspective of controlling the free rate Fb to be greater than 10% by volume and less than 30% by volume, the content of inorganic particles (preferably silica particles) is preferably greater than 1.0% by mass and less than 7.0% by mass, more preferably greater than 1.5% by mass and less than 6.0% by mass, and further preferably greater than 2.0% by mass and less than 5.5% by mass, relative to the entire toner.

[0184] From the perspective of controlling the ratio Fa / Fb, the mass basis ratio (layered structure compound particles / inorganic particles) of the content of layered structure compound particles and the content of inorganic particles (preferably silica particles) contained in the toner of this embodiment is preferably 0.01 to 0.50, more preferably 0.015 to 0.30, and further preferably 0.02 to 0.10.

[0185] [Other additives]

[0186] The toner of this embodiment may contain other external additives in addition to the layered structure compound particles and the inorganic particles. Examples of other external additives include resin particles (resin particles such as polystyrene, polymethyl methacrylate, and melamine resin), detergent activators (such as metal salts of higher fatty acids represented by zinc stearate, and particles of fluorine-based high molecular weight bodies).

[0187] When the toner of this embodiment contains other external additives in addition to the layered structure compound particles and the inorganic particles, the total amount of other external additives added is preferably 0.01 mass % to 5.0 mass %, more preferably 0.01 mass % to 2.0 mass %, relative to the toner particles.

[0188] [Toner Manufacturing Method]

[0189] The toner according to the present embodiment is obtained by manufacturing toner particles and then adding an external additive to the toner particles.

[0190] The toner particles can be produced by any of dry methods (e.g., kneading and pulverization methods) and wet methods (e.g., aggregation and merging methods, suspension polymerization methods, dissolution and suspension methods, etc.). These methods are not particularly limited, and known methods can be used. Among these, it is preferable to obtain the toner particles by the aggregation and merging method.

[0191] Specifically, for example, in the case of manufacturing toner particles by an agglomeration and merging method, the toner particles are manufactured through the following steps: a step of preparing a resin particle dispersion in which resin particles serving as a binding resin are dispersed (resin particle dispersion preparation step); a step of agglomerating resin particles (and other particles if necessary) in the resin particle dispersion (in a dispersion after mixing other particle dispersions if necessary) to form agglomerated particles (agglomerated particle formation step); and a step of heating the agglomerated particle dispersion in which the agglomerated particles are dispersed to fuse / merge (fusion / unity) the agglomerated particles to form toner particles (fusion / merging step).

[0192] The details of each step are described below.

[0193] In the following description, a method for obtaining toner particles containing a colorant and a release agent is described, but the colorant and the release agent are additives used as needed. Of course, other additives besides the colorant and the release agent may also be used.

[0194] - Resin particle dispersion preparation step -

[0195] A resin particle dispersion in which resin particles as a binder resin are dispersed is prepared, and at the same time, for example, a colorant particle dispersion in which colorant particles are dispersed and a release agent particle dispersion in which release agent particles are dispersed are prepared.

[0196] The resin particle dispersion is prepared, for example, by dispersing the resin particles in a dispersion medium using a surfactant.

[0197] Examples of the dispersion medium used for the resin particle dispersion include aqueous media.

[0198] Examples of the aqueous medium include water such as distilled water and ion-exchanged water, alcohols, etc. These media may be used alone or in combination of two or more.

[0199] Examples of surfactants include anionic surfactants such as sulfate ester salts, sulfonates, phosphates, and soaps; cationic surfactants such as amine salts and quaternary ammonium salts; nonionic surfactants such as polyethylene glycols, alkylphenol ethylene oxide adducts, and polyols; and the like. Among these, anionic surfactants and cationic surfactants can be particularly mentioned. Nonionic surfactants can also be used in combination with anionic surfactants or cationic surfactants.

[0200] The surfactant may be used alone or in combination of two or more.

[0201] In the resin particle dispersion, as a method for dispersing the resin particles in the dispersion medium, for example, a common dispersion method using a rotary shearing homogenizer or a ball mill, sand mill, bead mill, etc. with a medium can be cited. In addition, depending on the type of resin particles, the resin particles can also be dispersed in the dispersion medium using a phase inversion emulsification method. The phase inversion emulsification method is a method in which the resin to be dispersed is dissolved in a hydrophobic organic solvent that can dissolve the resin, a base is added to the organic continuous phase (O phase) for neutralization, and then an aqueous medium (W phase) is added to thereby invert the phase from W / O to O / W, so that the resin is dispersed in the aqueous medium in a particle form.

[0202] The volume average particle size of the resin particles dispersed in the resin particle dispersion is, for example, preferably 0.01 μm or more and 1 μm or less, more preferably 0.08 μm or more and 0.8 μm or less, and further preferably 0.1 μm or more and 0.6 μm or less.

[0203] The volume average particle size of the resin particles is determined by using a particle size distribution obtained by measurement using a laser diffraction particle size distribution measuring device (e.g., LA-700 manufactured by Horiba, Ltd.). For the divided particle size range (segment), a cumulative distribution is plotted for volume from the small particle size side, and the particle size at the cumulative 50% point relative to all particles is measured, which is taken as the volume average particle size D50v. The volume average particle size of particles in other dispersions is measured in the same manner.

[0204] The content of the resin particles contained in the resin particle dispersion is preferably 5% by mass or more and 50% by mass or less, and more preferably 10% by mass or more and 40% by mass or less.

[0205] For example, a colorant particle dispersion and a release agent particle dispersion are prepared in the same manner as the resin particle dispersion. That is, the volume average particle size of the particles in the resin particle dispersion, the dispersion medium, the dispersion method, and the content of the particles are the same for the colorant particles dispersed in the colorant particle dispersion and the release agent particles dispersed in the release agent particle dispersion.

[0206] - Agglomerated Particle Formation Step-

[0207] Next, the resin particle dispersion, the colorant particle dispersion, and the release agent particle dispersion are mixed.

[0208] Then, the resin particles, the colorant particles, and the release agent particles are heterogeneously aggregated in the mixed dispersion to form aggregated particles containing the resin particles, the colorant particles, and the release agent particles and having a diameter close to that of the target toner particles.

[0209] Specifically, for example, a coagulant is added to the mixed dispersion, and the pH of the mixed dispersion is adjusted to acidity (for example, pH 2 to 5), a dispersion stabilizer is added as needed, and then heated to a temperature close to the glass transition temperature of the resin particles (specifically, for example, the glass transition temperature of the resin particles is -30°C to the glass transition temperature of -10°C), so that the particles dispersed in the mixed dispersion are agglomerated to form agglomerated particles.

[0210] In the aggregated particle forming step, for example, a coagulant may be added at room temperature (e.g., 25° C.) while the mixed dispersion is stirred using a rotary shearing homogenizer, the pH of the mixed dispersion is adjusted to acidic (e.g., pH 2 to 5), a dispersion stabilizer may be added as needed, and then the mixture may be heated.

[0211] Examples of the coagulant include surfactants having opposite polarity to the surfactant contained in the mixed dispersion, inorganic metal salts, and divalent or higher metal complexes. When a metal complex is used as the coagulant, the amount of surfactant used is reduced and the charging characteristics are improved.

[0212] If necessary, an additive that forms a complex or similar bond with the metal ion of the coagulant may be used together with the coagulant. As the additive, a chelating agent is preferably used.

[0213] Examples of the inorganic metal salt include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate; inorganic metal salt polymers such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide; and the like.

[0214] As the chelating agent, a water-soluble chelating agent can be used. Examples of the chelating agent include hydroxycarboxylic acids such as tartaric acid, citric acid, and gluconic acid; aminocarboxylic acids such as iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), and ethylenediaminetetraacetic acid (EDTA); and the like.

[0215] The amount of the chelating agent added is 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, based on 100 parts by mass of the resin particles.

[0216] - Fusion / Merge Steps-

[0217] Next, the aggregated particle dispersion containing the dispersed aggregated particles is heated to, for example, a temperature higher than the glass transition temperature of the resin particles (eg, 10° C. to 30° C. higher than the glass transition temperature of the resin particles) to fuse / combine the aggregated particles to form toner particles.

[0218] Through the above steps, toner particles are obtained.

[0219] After obtaining a dispersion of aggregated particles dispersed therein, toner particles can be manufactured by the following steps: further mixing the dispersion of aggregated particles with a dispersion of resin particles dispersed therein, agglomerating the resin particles so as to further adhere to the surfaces of the aggregated particles to form second aggregated particles; and heating the second dispersion of aggregated particles dispersed therein to fuse / merge the second aggregated particles to form toner particles with a core / shell structure.

[0220] After the fusion / merging step is completed, the toner particles formed in the solution are subjected to a known washing step, a solid-liquid separation step, and a drying step to obtain dry toner particles. Regarding the washing step, from the perspective of charging performance, replacement washing using ion exchange water can be fully implemented. Regarding the solid-liquid separation step, from the perspective of productivity, suction filtration, pressure filtration, etc. can be implemented. Regarding the drying step, from the perspective of productivity, freeze drying, airflow drying, fluidized bed drying, vibration fluidized bed drying, etc. can be implemented.

[0221] Thereafter, for example, an external additive is added to the obtained dry toner particles and mixed, thereby producing the toner of the present embodiment. The mixing can be performed using, for example, a V-type blender, a Henschel mixer, a Loedige mixer, etc. Furthermore, coarse particles of the toner can be removed using a vibration sieving machine, a wind sieving machine, etc. as needed.

[0222] In order to control the free rate Fa and the free rate Fb, the external additive can be added to the toner particles in multiple times (for example, twice). The earlier the external additive is added to the toner particles, the easier it is to adhere to the toner particles and the harder it is to be released from the toner particles.

[0223] <Electrostatic Image Developer>

[0224] The electrostatic image developer according to the present embodiment includes at least the toner according to the present embodiment.

[0225] The electrostatic image developer of the present embodiment may be a one-component developer containing only the toner of the present embodiment, or may be a two-component developer in which the toner and a carrier are mixed.

[0226] The carrier is not particularly limited, and known carriers can be cited. Examples of the carrier include: a coated carrier in which a core material formed of magnetic powder is coated with a resin; a magnetic powder dispersion carrier in which magnetic powder is dispersed and mixed in a matrix resin; a resin impregnated carrier in which a porous magnetic powder is impregnated with a resin; and the like. The magnetic powder dispersion carrier and the resin impregnated carrier may also be a carrier in which the constituent particles of the carrier are used as a core material and the surface thereof is coated with a resin.

[0227] Examples of the magnetic powder include magnetic metals such as iron, nickel, and cobalt; and magnetic oxides such as ferrite and magnetite.

[0228] Examples of the coating resin and base resin include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylate copolymer, pure silicone resin or modified products thereof containing organic siloxane bonds, fluororesins, polyesters, polycarbonates, phenolic resins, epoxy resins, etc. The coating resin and base resin may contain other additives such as conductive particles. Examples of the conductive particles include particles of metals such as gold, silver, and copper, carbon black, titanium oxide, zinc oxide, tin oxide, barium sulfate, aluminum borate, and potassium titanate.

[0229] When utilizing the surface of the resin coated core material, it is possible to cite a method of coating with a coating layer formed by dissolving the coating resin and various additives (used as needed) in a suitable solvent, etc. The solvent is not particularly limited and can be selected by considering the type of the resin used, coating suitability, etc.

[0230] Specific resin coating methods include: an immersion method, in which the core material is immersed in a coating layer forming solution; a spray method, in which the coating layer forming solution is sprayed onto the surface of the core material; a fluidized bed method, in which the coating layer forming solution is sprayed while the core material is suspended by flowing air; a kneading coater method, in which the core material of the carrier is mixed with the coating layer forming solution in a kneading coater and then the solvent is removed; and the like.

[0231] The mixing ratio (mass ratio) of the toner and the carrier in the two-component developer is preferably toner:carrier=1:100 to 30:100, and more preferably 3:100 to 20:100.

[0232] <Image Forming Apparatus, Image Forming Method>

[0233] The image forming device of the present embodiment comprises: an image holder; a charging mechanism that charges the surface of the image holder; an electrostatic image forming mechanism that forms an electrostatic image on the charged surface of the image holder; a developing mechanism that stores an electrostatic image developer and develops the electrostatic image formed on the surface of the image holder into a toner image using the electrostatic image developer; an intermediate transfer body to which the toner image formed on the surface of the image holder is transferred; a primary transfer mechanism that transfers the toner image formed on the surface of the image holder to the surface of the intermediate transfer body; and a secondary transfer mechanism. , which transfers the toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium; a fixing mechanism, which fixes the toner image transferred to the surface of the recording medium; an image holder cleaning mechanism, which has a scraper in contact with the surface of the image holder, and uses the scraper to clean the toner remaining on the surface of the image holder after the toner image is transferred; and an intermediate transfer cleaning mechanism, which has a scraper in contact with the surface of the intermediate transfer body, and uses the scraper to clean the toner remaining on the surface of the intermediate transfer body after the toner image is transferred to the surface of the recording medium. And, as an electrostatic image developer, the electrostatic image developer of this embodiment is applied.

[0234] An image forming method (image forming method of this embodiment) having the following steps is implemented using the image forming device of this embodiment: a charging step of charging the surface of an image holder; an electrostatic image forming step of forming an electrostatic image on the charged surface of the image holder; a developing step of developing the electrostatic image formed on the surface of the image holder into a toner image using the electrostatic image developer of this embodiment; a primary transfer step of transferring the toner image formed on the surface of the image holder to the surface of an intermediate transfer body; a secondary transfer step of transferring the toner image transferred to the surface of the intermediate transfer body to the surface of a recording medium; a fixing step of fixing the toner image transferred to the surface of the recording medium; an image holder cleaning step of bringing a scraper into contact with the surface of the image holder after the toner image is transferred to clean the toner remaining on the surface of the image holder; and an intermediate transfer body cleaning step of bringing a scraper into contact with the surface of the intermediate transfer body after the toner image is transferred to the surface of the recording medium to clean the toner remaining on the surface of the intermediate transfer body.

[0235] The image forming apparatus of the present embodiment may be a known image forming apparatus, for example, an apparatus including a static elimination mechanism for eliminating static electricity by irradiating a surface of an image holder with static elimination light after transfer of a toner image and before charging.

[0236] In the image forming apparatus of this embodiment, for example, the part including the developing mechanism may be a cartridge structure (processing cartridge) that is detachable from the image forming apparatus. As the processing cartridge, for example, a processing cartridge that stores the electrostatic image developer of this embodiment and has a developing mechanism is preferably used.

[0237] An example of the image forming apparatus according to the present embodiment is shown below, but the present invention is not limited thereto. In the following description, the main parts shown in the drawings are described, and the other descriptions are omitted.

[0238] Figure 1 2 is a diagram schematically showing the structure of the image forming apparatus according to the present embodiment.

[0239] Figure 1 The image forming apparatus shown in the figure is provided with first to fourth image forming units 10Y, 10M, 10C, 10K (image forming mechanism) of the electrophotographic method for outputting images of yellow (Y), magenta (M), cyan (C), and black (K) colors based on color separation image data. These image forming units (hereinafter sometimes referred to as "units") 10Y, 10M, 10C, 10K are arranged in parallel with each other at a predetermined distance in the horizontal direction. These units 10Y, 10M, 10C, 10K may be process cartridges that are detachable from the image forming apparatus.

[0240] Above each unit 10Y, 10M, 10C, 10K, an intermediate transfer belt (an example of an intermediate transfer body) 20 is extended through each unit. The intermediate transfer belt 20 is wound around a driving roller 22 and a supporting roller 24 so as to run in a direction from the first unit 10Y to the fourth unit 10K. The supporting roller 24 is forced in a direction away from the driving roller 22 by a spring (not shown) or the like, and tension is applied to the intermediate transfer belt 20 wound around the two. An intermediate transfer belt cleaning device 30 is provided on the image holding body side of the intermediate transfer belt 20 so as to face the driving roller 22.

[0241] The intermediate transfer belt 20 is, for example, a laminate of a base layer and a surface layer disposed on the outer peripheral surface of the base layer. The base layer includes, for example, a resin such as a polyimide resin, a polyamide resin, a polyamide-imide resin, a polyether ester resin, a polyarylate resin, a polyester resin, and a conductive agent. The surface layer includes, for example, at least one of the above resins, a fluororesin, and a conductive agent. The thickness of the intermediate transfer belt 20 is, for example, not less than 50 μm and not more than 100 μm.

[0242] Yellow, magenta, cyan and black toners stored in toner cartridges 8Y, 8M, 8C and 8K are supplied to developing devices (an example of developing mechanisms) 4Y, 4M, 4C and 4K of the respective units 10Y, 10M, 10C and 10K.

[0243] The first to fourth units 10Y, 10M, 10C, and 10K have the same configuration and operation, and therefore the first unit 10Y disposed on the upstream side in the running direction of the intermediate transfer belt and forming a yellow image will be described as a representative.

[0244] The first unit 10Y has a photoreceptor 1Y that functions as an image holder. The following are arranged in order around the photoreceptor 1Y: a charging roller (an example of a charging mechanism) 2Y that charges the surface of the photoreceptor 1Y to a preset potential; an exposure device (an example of an electrostatic image forming mechanism) 3 that forms an electrostatic image by exposing the charged surface using a laser beam 3Y based on a color separation image signal; a developing device (an example of a developing mechanism) 4Y that supplies the charged toner to the electrostatic image to develop the electrostatic image; a primary transfer roller 5Y (an example of a primary transfer mechanism) that transfers the developed toner image to the intermediate transfer belt 20; and a photoreceptor cleaning device (an example of an image holder cleaning mechanism) 6Y that removes the toner remaining on the surface of the photoreceptor 1Y after the primary transfer.

[0245] The primary transfer roller 5Y is arranged inside the intermediate transfer belt 20 and is provided at a position facing the photosensitive body 1Y. The primary transfer rollers 5Y, 5M, 5C, and 5K of each unit are connected to bias power supplies (not shown) for applying primary transfer bias. Each bias power supply changes the value of the transfer bias applied to each primary transfer roller under the control of a control unit (not shown).

[0246] The photoreceptor cleaning device 6Y includes a cleaning blade that contacts the surface of the photoreceptor 1Y. The cleaning blade contacts the surface of the photoreceptor 1Y that continues to rotate after the toner image is transferred to the intermediate transfer belt 20, and removes the toner remaining on the surface of the photoreceptor 1Y.

[0247] Downstream of the fourth unit 10K, there are provided a secondary transfer roller (an example of a secondary transfer mechanism) 26 and a support roller 24. The secondary transfer roller 26 is disposed on the image holding surface side of the intermediate transfer belt 20, and the support roller 24 is disposed in contact with the inner surface of the intermediate transfer belt 20, and the secondary transfer roller 26 and the support roller 24 constitute a secondary transfer section.

[0248] The intermediate transfer belt cleaning device 30 includes a cleaning blade that contacts the surface of the intermediate transfer belt 20. The cleaning blade contacts the surface of the intermediate transfer belt 20 that continues to run after transferring the toner image to the recording medium, and removes the toner remaining on the surface of the intermediate transfer belt 20. Examples of the material of the cleaning blade include thermosetting polyurethane rubber, silicone rubber, fluororubber, ethylene-propylene-diene rubber, and the like.

[0249] Next, the operation of forming a yellow image in the first unit 10Y will be described.

[0250] First, before the operation, the surface of the photoreceptor 1Y is charged to a potential of -600 V to -800 V by the charging roller 2Y.

[0251] The photoreceptor 1Y has a conductivity (e.g., a volume resistivity of 1×10 -6The photosensitive layer is formed by laminating a photosensitive layer on a substrate with a resistance of 100 Ωcm or less. The photosensitive layer generally has a high resistance (resistance of a common resin), but has a property that the resistivity of the portion irradiated with the laser beam changes when the laser beam is irradiated. Therefore, according to the yellow image data sent from the control unit (not shown), the laser beam 3Y is irradiated from the exposure device 3 to the charged surface of the photoreceptor 1Y. As a result, an electrostatic image of a yellow image pattern is formed on the surface of the photoreceptor 1Y.

[0252] The electrostatic image is an image formed on the surface of the photoreceptor 1Y by charging, which is a so-called negative latent image. The negative latent image is formed as follows: the resistivity of the irradiated portion of the photosensitive layer is reduced by using the laser beam 3Y, so that the charged charge on the surface of the photoreceptor 1Y flows; on the other hand, the charge of the portion not irradiated with the laser beam 3Y remains, thereby forming the negative latent image.

[0253] The electrostatic image formed on the photoreceptor 1Y rotates to a preset development position as the photoreceptor 1Y runs. At the development position, the electrostatic image on the photoreceptor 1Y is developed into a toner image by the developing device 4Y and visualized.

[0254] The developing device 4Y stores an electrostatic image developer containing, for example, at least a yellow toner and a carrier. The yellow toner is frictionally charged by being stirred inside the developing device 4Y, and has a charge of the same polarity (negative polarity) as the charge charged on the photoreceptor 1Y, and is held on the developer roller (an example of a developer holding member). After that, the surface of the photoreceptor 1Y passes through the developing device 4Y, whereby the yellow toner is electrostatically attached to the latent image portion on the surface of the photoreceptor 1Y that has been de-charged, and the latent image is developed using the yellow toner. The photoreceptor 1Y formed with the yellow toner image continues to run at a preset speed, and the toner image developed on the photoreceptor 1Y is conveyed to a preset primary transfer position.

[0255] When the yellow toner image on the photoreceptor 1Y is transported to the primary transfer position, a primary transfer bias is applied to the primary transfer roller 5Y, and the electrostatic force from the photoreceptor 1Y toward the primary transfer roller 5Y acts on the toner image, so that the toner image on the photoreceptor 1Y is transferred to the intermediate transfer belt 20. The transfer bias applied at this time has a polarity (+) opposite to the polarity (-) of the toner, and is controlled to, for example, +10 μA by a control section (not shown) in the first unit 10Y.

[0256] The photoreceptor 1Y, after transferring the toner image to the intermediate transfer belt 20, continues to rotate and contacts a cleaning blade provided in the photoreceptor cleaning device 6Y. The toner remaining on the photoreceptor 1Y is removed and recovered by the photoreceptor cleaning device 6Y.

[0257] The primary transfer bias applied to the primary transfer rollers 5M, 5C, and 5K after the second unit 10M is also controlled in accordance with the first unit.

[0258] In this way, the intermediate transfer belt 20 to which the yellow toner image has been transferred by the first unit 10Y is sequentially transported through the second to fourth units 10M, 10C, and 10K, and the toner images of the respective colors are multiply transferred in a superimposed manner.

[0259] The intermediate transfer belt 20 to which the four-color toner image has been multi-transferred by the first to fourth units arrives at the secondary transfer section, which is composed of the intermediate transfer belt 20, the support roller 24 in contact with the inner surface of the intermediate transfer belt, and the secondary transfer roller (an example of the secondary transfer mechanism) 26 arranged on the image holding surface side of the intermediate transfer belt 20. On the other hand, the recording paper (an example of the recording medium) P is fed to the gap between the secondary transfer roller 26 and the intermediate transfer belt 20 by the feeding member at a preset timing, and a secondary transfer bias is applied to the support roller 24. The transfer bias applied at this time has the same (-) polarity as the polarity (-) of the toner, and the electrostatic force from the intermediate transfer belt 20 to the recording paper P acts on the toner image, so that the toner image on the intermediate transfer belt 20 is transferred to the recording paper P. The secondary transfer bias at this time is determined based on the resistance detected by the resistance detection mechanism (not shown) that detects the resistance of the secondary transfer section, and the voltage is controlled.

[0260] After transferring the toner image to the recording paper P, the intermediate transfer belt 20 continues to run and contacts a cleaning blade provided in the intermediate transfer belt cleaning device 30. The toner remaining on the intermediate transfer belt 20 is removed and recovered by the intermediate transfer belt cleaning device 30.

[0261] The recording paper P to which the toner image has been transferred is fed to a pressure-contact portion (nip portion) of a pair of fixing rollers in a fixing device (an example of a fixing mechanism) 28 , and the toner image is fixed to the recording paper P, thereby forming a fixed image.

[0262] Examples of the recording paper P to which the toner image is transferred include plain paper used in electrophotographic copy machines, printers, and the like. Examples of the recording medium include, in addition to the recording paper P, OHP transparent films and the like.

[0263] In order to further improve the smoothness of the image surface after fixing, the surface of the recording paper P is preferably smooth. For example, coated paper obtained by coating the surface of ordinary paper with a resin or the like, art paper for printing, etc. are preferably used.

[0264] The recording paper P on which the color image has been fixed is sent to the discharge portion, and a series of color image forming operations are completed.

[0265] <Process Cartridge, Toner Cartridge>

[0266] The processing box of the present embodiment is a processing box that is loaded and unloaded in an image forming device, and comprises: an image retaining body; a developing mechanism that stores the electrostatic image developer of the present embodiment and uses the electrostatic image developer to develop the electrostatic image formed on the surface of the image retaining body into a toner image; an intermediate transfer body to which the toner image formed on the surface of the image retaining body is transferred; an image retaining body cleaning mechanism that has a scraper in contact with the surface of the image retaining body and uses the scraper to clean the toner remaining on the surface of the image retaining body after the toner image is transferred; and an intermediate transfer body cleaning mechanism that has a scraper in contact with the surface of the intermediate transfer body and uses the scraper to clean the toner remaining on the surface of the intermediate transfer body after the toner image is transferred to the surface of the recording medium.

[0267] The process cartridge of the present embodiment is not limited to the above-described configuration, and may be configured to further include at least one selected from a charging mechanism, an electrostatic image forming mechanism, and the like, for example.

[0268] An example of the process cartridge according to the present embodiment is shown below, but the present invention is not limited thereto. In the following description, the main parts shown in the drawings are described, and the description of other parts is omitted.

[0269] Figure 2 This is a schematic structural diagram showing an example of a process cartridge that is attached to and detached from the image forming apparatus according to the present embodiment. Figure 2 In the process cartridge 200 shown, a photosensitive body 107 (an example of an image holding body), a charging roller 108 (an example of a charging mechanism) arranged around the photosensitive body 107, a developing device 111 (an example of a developing mechanism), and a photosensitive body cleaning device 113 (an example of an image holding body cleaning mechanism) are integrated by a housing 117 having a mounting guide 116 and an opening 118 for exposure, and further an intermediate transfer belt 120 (an example of an intermediate transfer body), a primary transfer roller 121 (an example of a primary transfer mechanism), a secondary transfer roller 122 (an example of a secondary transfer mechanism), a support roller 123, a driving roller 124, and an intermediate transfer belt cleaning device 125 (an example of an intermediate transfer body cleaning mechanism) are combined. The photosensitive body cleaning device 113 has a scraper in contact with the photosensitive body 107. The intermediate transfer belt cleaning device 125 has a scraper in contact with the intermediate transfer belt 120. When the photoreceptor 107 is placed in an image forming apparatus and an image is formed, the photoreceptor 107 is exposed by an exposure device 109 (an example of an electrostatic image forming mechanism) to form an electrostatic image on the surface.

[0270] Next, the toner cartridge according to the present embodiment will be described.

[0271] The toner cartridge of the present embodiment stores the toner of the present embodiment and is attached to and detached from the image forming apparatus. The toner cartridge stores replenishment toner to be supplied to a developing mechanism provided in the image forming apparatus.

[0272] Figure 1 The image forming apparatus shown is an image forming apparatus having a structure of attaching and detaching toner cartridges 8Y, 8M, 8C, and 8K, and the developing devices 4Y, 4M, 4C, and 4K are connected to the toner cartridges corresponding to the respective developing devices (colors) by toner supply pipes not shown. In addition, when the toner stored in the toner cartridge is insufficient, the toner cartridge is replaced.

[0273] [Example]

[0274] The embodiments of the present invention are described in detail below by way of examples, but the embodiments of the present invention are not limited to these examples. In the following description, "parts" and "%" are based on mass unless otherwise specified.

[0275] <Preparation of Toner>

[0276] [Preparation of amorphous polyester resin dispersion (A1)]

[0277] Ethylene glycol: 37 parts

[0278] Neopentyl glycol: 65 parts

[0279] 1,9-nonanediol: 32 parts

[0280] Terephthalic acid: 96 parts

[0281] The above materials were put into a flask, and the temperature was raised to 200°C over 1 hour. After confirming that the reaction system was uniformly stirred, 1.2 parts of dibutyltin oxide were added. The temperature was raised to 240°C over 6 hours while distilling off the generated water. Stirring was continued at 240°C for 4 hours to obtain an amorphous polyester resin (acid value 9.4 mgKOH / g, weight average molecular weight 13,000, glass transition temperature 62°C). The amorphous polyester resin was kept in a molten state and conveyed to an emulsifier disperser (Cavitron CD1010, Eurotec) at a rate of 100 g per minute. A 0.37% concentration of dilute ammonia water prepared by diluting the reagent ammonia water with ion exchange water was added to a tank separately, heated to 120°C using a heat exchanger, and conveyed to the emulsifier disperser at a rate of 0.1 liter per minute together with the amorphous polyester resin. The emulsifier disperser was operated at a rotor rotation speed of 60 Hz and a pressure of 5 kg / cm 2 The reaction mixture was operated under the conditions of , to obtain an amorphous polyester resin dispersion (A1) having a volume average particle size of 160 nm and a solid content of 20%.

[0282] [Preparation of Crystalline Polyester Resin Dispersion (C1)]

[0283] Sebacic acid: 81 parts

[0284] Hexanediol: 47 parts

[0285] The above materials were placed in a flask, and the temperature was raised to 160°C over 1 hour. After confirming that the reaction system was uniformly stirred, 0.03 parts of dibutyltin oxide was added. The temperature was raised to 200°C over 6 hours while distilling off the generated water, and stirring was continued at 200°C for 4 hours. The reaction solution was then cooled, solid-liquid separation was performed, and the solid matter was dried at a temperature of 40°C / under reduced pressure to obtain a crystalline polyester resin (B1) (melting point 64°C, weight average molecular weight 15,000).

[0286] Crystalline polyester resin (B1): 50 parts

[0287] Anionic surfactant (made by Daiichi Kogyo Chemical Co., Ltd., NEOGENRK): 2 parts

[0288] Ion exchange water: 200 parts

[0289] The above materials were heated to 120°C, fully dispersed with a homogenizer (ULTRA-TURRAXT50, IKA), and then dispersed with a pressure discharge homogenizer. After the volume average particle size reached 180 nm, the particles were recovered to obtain a crystalline polyester resin dispersion (C1) with a solid content of 20%.

[0290] [Preparation of Release Agent Particle Dispersion (W1)]

[0291] Solid paraffin wax (HNP-9 manufactured by Nippon Seira Co., Ltd.): 100 parts

[0292] Anionic surfactant (made by Daiichi Kogyo Chemical Co., Ltd., NEOGENRK): 1 part

[0293] Ion exchange water: 350 parts

[0294] The above materials were mixed, heated to 100°C, dispersed using a homogenizer (ULTRA-TURRAXT50 manufactured by IKA), and then dispersed using a pressure-dispensing Gaulin homogenizer to obtain a release agent particle dispersion in which release agent particles having a volume average particle size of 200 nm were dispersed. Ion-exchanged water was added to the release agent particle dispersion to adjust the solid content to 20%, and the resulting dispersion was used as a release agent particle dispersion (W1).

[0295] [Preparation of Colorant Particle Dispersion (D1)]

[0296] Cyan pigment (Pigment Blue 15:3, Dainichi Seika Industries): 50 parts

[0297] Anionic surfactant (manufactured by Daiichi Kogyo Chemical Co., Ltd., NEOGENRK): 5 parts

[0298] Ion exchange water: 195 parts

[0299] The above materials were mixed and dispersed for 60 minutes using a high-pressure impact disperser (Ultimaizer HJP30006, Sugino Machine Co., Ltd.) to obtain a colorant particle dispersion (D1) having a solid content of 20%.

[0300] [Production of Cyan Toner Particles (E1)]

[0301] Ion exchange water: 200 parts

[0302] Amorphous polyester resin dispersion (A1): 150 parts

[0303] Crystalline polyester resin dispersion (C1): 10 parts

[0304] Release agent particle dispersion (W1): 10 parts

[0305] Colorant particle dispersion (D1): 15 parts

[0306] Anionic surfactant (TaycaPower): 2.8 parts

[0307] The above materials were placed in a round stainless steel flask, 0.1N nitric acid was added to adjust the pH to 3.5, and then an aqueous solution of polyaluminum chloride (manufactured by Oji Paper Co., Ltd., 30% powder) was added to dissolve 2 parts of polyaluminum chloride in 30 parts of ion exchange water. After dispersion at 30°C using a homogenizer (ULTRA-TURRAXT50 manufactured by IKA), it was heated to 45°C in a heating oil bath and maintained until the volume average particle size reached 4.9μm. Then, 60 parts of amorphous polyester resin dispersion (A1) were added and maintained for 30 minutes. Then, after the volume average particle size reached 5.2μm, 60 parts of amorphous polyester resin dispersion (A1) were further added and maintained for 30 minutes. Then, 20 parts of a 10% NTA (nitrilotriacetic acid) metal salt aqueous solution (Chelest70, manufactured by Chelest Co., Ltd.) were added, and a 1N sodium hydroxide aqueous solution was added to adjust the pH to 9.0. Then, 1 part of anionic surfactant (Tayca Power) was added, and the mixture was heated to 85° C. and maintained for 5 hours while being stirred. The mixture was then cooled to 20° C. at a rate of 20° C. / min. The mixture was filtered, washed thoroughly with ion exchange water, and dried to obtain cyan toner particles (E1) having a volume average particle size of 5.7 μm and an average circularity of 0.971.

[0308] <Preparation of Layered Structure Compound Particles>

[0309] [Production of melamine cyanurate granules]

[0310] Commercially available melamine cyanurate (MC-4500 manufactured by Nissan Chemical Industries, Ltd.) was pulverized with a jet mill and classified to obtain melamine cyanurate particles (1) to (6) having different average particle sizes.

[0311] Melamine cyanurate particles (1): primary particles having a number average particle size of 0.5 μm and monodispersed.

[0312] Melamine cyanurate particles (2): primary particles having a number average particle size of 0.2 μm and monodispersed.

[0313] Melamine cyanurate particles (3): primary particles having a number average particle size of 1.2 μm and monodispersed.

[0314] Melamine cyanurate particles (4): primary particles having a number average particle size of 5.0 μm and monodispersed.

[0315] Melamine cyanurate particles (5): primary particles having a number average particle size of 18.0 μm and monodispersed.

[0316] Melamine cyanurate particles (6): primary particles having a number average particle size of 65.0 μm and monodispersed.

[0317] <Preparation of carrier>

[0318] Mix 14 parts of toluene, 2 parts of styrene-methyl methacrylate copolymer (polymerization mass ratio 90:10, weight average molecular weight 80,000) and 0.2 parts of carbon black (R330 manufactured by Cabot Corporation), and stir with a stirrer for 10 minutes to prepare a dispersion. Next, load the dispersion and 100 parts of ferrite particles (volume average particle size 36 μm) into a vacuum degassing kneader, stir at 60°C for 30 minutes, then degas while heating and reducing pressure to dry. Next, use a sharp jet to classify and remove fine powder and coarse powder to obtain a resin-coated carrier. The volume average particle size of the resin-coated carrier is 36 μm.

[0319] <Example 1>

[0320] 100 parts by mass of cyan toner particles (E1), 2.00 parts by mass of first hydrophobic silica particles (silica particles obtained by hydrophobizing sol-gel silica with hexamethyldisilazane, with a number average particle size of 50 nm), and 1.00 parts by mass of second hydrophobic silica particles (silica particles obtained by hydrophobizing sol-gel silica with hexamethyldisilazane, with a number average particle size of 120 nm) were placed in a sample mill and mixed at 10,000 rpm for 30 seconds. Next, 0.100 parts by mass of melamine cyanurate particles (1) and 0.020 parts by mass of melamine cyanurate particles (5) were placed in a sample mill and mixed at 10,000 rpm for 30 seconds. After mixing, the mixture was sieved using a vibrating sieve with a mesh size of 45 μm to obtain a toner. The toner and the carrier were charged into a V-type blender at a ratio of toner:carrier=5:100 (mass ratio), and stirred for 20 minutes to obtain a developer.

[0321] <Examples 2 to 12, Comparative Examples 1 to 2>

[0322] A toner and a developer were obtained in the same manner as in Example 1 except that the type or addition amount of the layered structure compound particles or the number average particle size or addition amount of the silica particles were changed according to the specifications shown in Table 1.

[0323] <Performance Evaluation>

[0324] [Color streaks generated in a high temperature and high humidity environment (wear of the photoreceptor cleaning blade)]

[0325] In an environment of 30°C and 85% relative humidity, 100,000 images with an image density of 1.5% were output on A4-sized paper using a modified 700 Digital Color Press manufactured by Fuji Xerox. Then, one solid image with a toner loading of 0.1 mg / cm was output on A4-sized paper.2 The half-tone image was visually observed, and the contact portion of the photoreceptor cleaning blade was observed using a microscope (VH6200, manufactured by KEYENCE) at a magnification of 100 times. The number of color fringes generated in the half-tone image and the state of the contact portion of the photoreceptor cleaning blade were graded according to the following criteria.

[0326] G1: There are 0 color streaks and the photoreceptor cleaning blade has no notches.

[0327] G2: There are 0 color streaks and the photoconductor cleaning blade is notched.

[0328] G3: There are 1 to 5 color streaks and the photoreceptor cleaning blade has a chip. Permissible range.

[0329] G4: There are 6 or more color streaks and the photoreceptor cleaning blade has a chip. This is not acceptable in practice.

[0330] [Color streaks in low temperature and low humidity environments (poor cleaning of the intermediate transfer belt)]

[0331] In an environment of temperature 10°C and relative humidity 10%, a modified 700 Digital Color Press manufactured by Fuji Xerox was used to output 100,000 images with an image density of 25.0% on A4 size paper. Then, 500 solid images with a toner loading of 0.1 mg / cm were output on A4 size paper. 2 The 10th, 50th, 100th, and 500th images were visually observed, and the total number of color fringes generated in the halftone images was ranked according to the following criteria.

[0332] G1: 0

[0333] G2: 1

[0334] G3: 2 to 5. Permissible range.

[0335] G4: More than 6. This is not practically acceptable.

[0336] [Transferability]

[0337] 20,000 test charts with an image density of 35% were continuously output on A4-sized embossed paper (Tokuju Tokai Paper Co., Ltd., Lesac 66) using a modified 700 Digital Color Press manufactured by Fuji Xerox Co., Ltd. at a temperature of 10°C and a relative humidity of 15%. When forming the image, the fixing temperature was set to 190°C and the fixing pressure was set to 4.0 kg / cm 2The image portion of the 20,000th image was observed using a 100x magnifying glass with a scale, and graded according to the following criteria.

[0338] G1: There is no uneven transfer of the image.

[0339] G2: The image is slightly unevenly transferred, but there is no problem in practical use.

[0340] G3: The image is unevenly transferred, but within the allowable range.

[0341] G4: The image is unevenly transferred, which is not acceptable in practical use.

[0342]

Claims

1. A toner for developing electrostatic images, in, The toner comprises toner particles, melamine cyanurate particles and inorganic particles. The number particle size distribution of the melamine cyanurate particles has at least one peak in the range of particle diameters of 0.1 μm to 1.5 μm and at least one peak in the range of particle diameters of 3 μm to 80 μm. The rate Fa of release of the melamine cyanurate particles released from the toner particles is 5% by volume or more and 20% by volume or less.

2. The electrostatic image developing toner according to claim 1, in, The rate Fa of release of the melamine cyanurate particles released from the toner particles is 5% by volume or more and 10% by volume or less.

3. The electrostatic image developing toner according to claim 1, in, The free rate Fb of the inorganic particles released from the toner particles is 10% by volume or more and 30% by volume or less.

4. The electrostatic image developing toner according to claim 3, in, The above-mentioned free rate Fb is not less than 10 volume % and not more than 20 volume %.

5. The electrostatic image developing toner according to claim 3, in, The ratio Fa / Fb of the above-mentioned free rate Fa to the above-mentioned free rate Fb is 0.20 or more and 0.50 or less.

6. The electrostatic image developing toner according to claim 5, in, The ratio Fa / Fb of the above-mentioned free rate Fa to the above-mentioned free rate Fb is 0.20 or less and 0.35 or less.

7. The electrostatic image developing toner according to claim 1, in, The content of the melamine cyanurate particles is 0.02 mass % or more and 0.50 mass % or less based on the entire electrostatic image developing toner.

8. The electrostatic image developing toner according to claim 1, in, The content of the inorganic particles is 1.0 mass % or more and 7.0 mass % or less based on the entire electrostatic image developing toner.

9. The electrostatic image developing toner according to claim 1, in, The inorganic particles include silica particles. 10 . An electrostatic image developer comprising the electrostatic image developing toner according to claim 1 . 11 . A toner cartridge that is detachably mounted in an image forming apparatus, the toner storing the electrostatic image developing toner according to claim 1 .

12. A process cartridge to be loaded and unloaded in an image forming apparatus, comprising: Image holding body; a developing mechanism storing the electrostatic image developer according to claim 10 and developing the electrostatic image formed on the surface of the image holding member into a toner image using the electrostatic image developer; an intermediate transfer body to which the toner image formed on the surface of the image holding body is transferred; an image holding body cleaning mechanism having a scraper in contact with the surface of the image holding body, and using the scraper to clean the toner remaining on the surface of the image holding body after the toner image is transferred; and The intermediate transfer body cleaning mechanism includes a scraper in contact with the surface of the intermediate transfer body, and uses the scraper to clean the toner remaining on the surface of the intermediate transfer body after the toner image is transferred to the surface of the recording medium.

13. An image forming apparatus comprising: Image holding body; A charging mechanism for charging the surface of the image holding body; An electrostatic image forming mechanism for forming an electrostatic image on the charged surface of the image holding member; a developing mechanism storing the electrostatic image developer according to claim 10 and developing the electrostatic image formed on the surface of the image holding member into a toner image using the electrostatic image developer; an intermediate transfer body to which the toner image formed on the surface of the image holding body is transferred; a primary transfer mechanism for transferring the toner image formed on the surface of the image holding body to the surface of the intermediate transfer body; a secondary transfer mechanism that transfers the toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium; a fixing mechanism for fixing the toner image transferred to the surface of the recording medium; an image holding body cleaning mechanism having a scraper in contact with the surface of the image holding body, and using the scraper to clean the toner remaining on the surface of the image holding body after the toner image is transferred; and The intermediate transfer body cleaning mechanism includes a scraper in contact with the surface of the intermediate transfer body, and uses the scraper to clean the toner remaining on the surface of the intermediate transfer body after the toner image is transferred to the surface of the recording medium.

14. An image forming method comprising the following steps: Charging, charging the surface of the image holding body; Electrostatic image formation, forming an electrostatic image on the charged surface of the image holding member; Developing, using the electrostatic image developer according to claim 10 to develop the electrostatic image formed on the surface of the image holding member into a toner image; primary transfer, transferring the toner image formed on the surface of the image holding body to the surface of the intermediate transfer body; Secondary transfer, transferring the toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium; Fixing, fixing the toner image transferred to the surface of the recording medium; cleaning the image holding body, bringing the scraper into contact with the surface of the image holding body after the toner image is transferred, and cleaning the toner remaining on the surface of the image holding body; and The intermediate transfer body cleaning is performed by bringing a scraper into contact with the surface of the intermediate transfer body after the toner image is transferred to the surface of the recording medium, thereby cleaning the toner remaining on the surface of the intermediate transfer body.

Images