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

Abstract

The present invention relates to a toner for developing electrostatic images, an electrostatic image developer, a toner cartridge, a process cartridge, an image forming apparatus, and a forming method. The toner for developing electrostatic images comprises toner particles, oil-treated agglomerated silica particles A, and silica particles B that have been subjected to a hydrophobic treatment other than the oil treatment and may be agglomerated or non-agglomerated. The average particle size Da of the agglomerated silica particles A and the average particle size Db of the silica particles B are in a relationship of Da≧Db. The toner contains no external additives other than the agglomerated silica particles A and the silica particles B, or contains an external additive other than the agglomerated silica particles A and the silica particles B, but the average particle size of the external additive is smaller than the average particle size Da.

Description

Technical Field

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

[0002] Japanese Patent Application Laid-Open No. 2014-114175 discloses surface-hydrophobic spherical silica particles having an average particle diameter of 0.01 μm to 5 μm in terms of volume-based median diameter and having at least a part of the surface hydrophobized, and a toner externally added with the surface-hydrophobic spherical silica particles. Summary of the Invention

[0003] Technical Problem to be Solved by the Invention

[0004] The technical problem to be solved by the present invention is to provide a toner for electrostatic image development which is more easily discharged from a supply toner storage unit as compared with a toner for electrostatic image development containing agglomerated silica particles A treated with oil and silica particles B which are hydrophobized by a treatment other than degreasing treatment and which may be either agglomerated or non-agglomerated, and having a relationship of average particle diameter Da of the agglomerated silica particles A and average particle diameter Db of the silica particles B of Da < Db.

[0005] Means for Solving the Technical Problem

[0006] According to a first aspect of the present invention, there is provided a toner for electrostatic image development, which contains: toner particles, agglomerated silica particles A treated with oil, and silica particles B which are hydrophobized by a treatment other than degreasing treatment and which may be either agglomerated or non-agglomerated; the average particle diameter Da of the agglomerated silica particles A and the average particle diameter Db of the silica particles B have a relationship of Da ≧ Db; the toner does not contain an external additive other than the agglomerated silica particles A and the silica particles B, or contains an external additive other than the agglomerated silica particles A and the silica particles B but the average particle diameter of the external additive is smaller than the average particle diameter Da.

[0007] According to a second aspect of the present invention, the ratio Da / Db of the average particle diameter Da to the average particle diameter Db is 1.0 or more and 2.0 or less.

[0008] According to a third aspect of the present invention, the mass-based ratio Ma / Mb of the content Ma of the agglomerated silica particles A to the content Mb of the silica particles B is 0.5 or more and 1.0 or less.

[0009] According to a fourth aspect of the present invention, the silica particles B include non-agglomerated particles of wet-process silica particles.

[0010] According to a fifth aspect of the present invention, the silica particles B include silica particles hydrophobized with 1,1,1,3,3,3-hexamethyldisilazane.

[0011] According to a sixth aspect of the present invention, the agglomerated silica particles A include agglomerated particles of fumed silica particles.

[0012] According to a seventh aspect of the present invention, the agglomerated silica particles A include agglomerated silica particles treated with silicone oil.

[0013] According to the eighth aspect of the present invention, the number-based frequency distribution of the particle size of the agglomerated silica particles A has two peaks: the first peak is in the particle size range of 80 nm to 110 nm, and the second peak is in the particle size range of 50 nm to 80 nm.

[0014] According to a ninth aspect of the present invention, the average particle diameter Da is not less than 70 nm and not more than 110 nm.

[0015] According to a tenth aspect of the present invention, the average particle size Db is not less than 20 nm and not more than 80 nm.

[0016] According to the eleventh aspect of the present invention, the coverage rate of the agglomerated silica particles A on the surfaces of the toner particles is 5% or more and 30% or less.

[0017] According to the twelfth aspect of the present invention, the coverage rate of all external additives on the surfaces of the toner particles is 60% or more and 100% or less.

[0018] According to the thirteenth aspect of the present invention, in the number-based frequency distribution of the particle sizes of all external additives, the proportion of particles in the range of 20 nm to 100 nm is 75% or more.

[0019] According to the fourteenth aspect of the present invention, tetrakis(trimethylsiloxy)silane is further contained.

[0020] According to the fifteenth aspect of the present invention, the content of tetrakis(trimethylsiloxy)silane is 0.01 ppm to 10 ppm on a mass basis.

[0021] According to a sixteenth aspect of the present invention, there is provided an electrostatic image developer comprising the above-mentioned electrostatic image developing toner.

[0022] According to a seventeenth aspect of the present invention, there is provided a toner cartridge storing the above-mentioned toner for developing an electrostatic image, the toner cartridge being attachable to and detachable from an image forming apparatus.

[0023] According to an eighteenth aspect of the present invention, in the rotary toner cartridge, a main body storing the electrostatic image developing toner rotates.

[0024] According to the 19th embodiment of the present invention, a processing box is provided, which is a processing box that is loaded and unloaded in an image forming device, and the processing box comprises: a developing mechanism that stores an electrostatic image developer and uses the above-mentioned electrostatic image developer to develop the electrostatic image formed on the surface of the image retaining body into a toner image; a toner box that stores the above-mentioned toner for electrostatic image development; and a toner supply path that connects the above-mentioned toner box and the above-mentioned developing mechanism and supplies the above-mentioned electrostatic image development toner in the above-mentioned toner box to the above-mentioned developing mechanism.

[0025] According to the 20th embodiment of the present invention, there is provided an image forming device comprising: an image retaining body; a charging mechanism for charging the surface of the image retaining body; an electrostatic image forming mechanism for forming an electrostatic image on the surface of the charged image retaining body; a developing mechanism for storing an electrostatic image developer and developing the electrostatic image formed on the surface of the image retaining body into a toner image using the electrostatic image developer; a transfer mechanism for transferring the toner image formed on the surface of the image retaining body to the surface of a recording medium; a fixing mechanism for fixing the toner image transferred to the surface of the recording medium; a replenishing toner storage section for storing the electrostatic image developing toner; and a toner replenishing path for connecting the replenishing toner storage section and the developing mechanism to replenish the electrostatic image developing toner in the replenishing toner storage section to the developing mechanism.

[0026] According to the 21st scheme of the present invention, an image forming method is provided, which has the following steps: a charging step of charging the surface of the image retaining body; an electrostatic image forming step of forming an electrostatic image on the surface of the charged image retaining body; a developing step of developing the electrostatic image formed on the surface of the image retaining body into a toner image using an electrostatic image developer; a transfer step of transferring the toner image formed on the surface of the image retaining body to the surface of the recording medium; a fixing step of fixing the toner image transferred to the surface of the recording medium; and a toner replenishing step of replenishing the electrostatic image developing toner in the replenishing toner storage section from a replenishing toner storage section storing the electrostatic image developing toner to the developing mechanism through a toner replenishing path connecting the replenishing toner storage section and the developing mechanism.

[0027] Effects of the Invention

[0028] According to the solutions of 1, 5, 6, 7, or 8 above, there is provided a toner for electrostatic image development, which has more excellent discharge property from the supply toner storage part as compared with a toner for electrostatic image development containing agglomerated silica particles A treated with oil and silica particles B which can be either agglomerated or non-agglomerated and are hydrophobized by a treatment other than degreasing treatment, and having a relationship of the average particle diameter Da of the agglomerated silica particles A and the average particle diameter Db of the silica particles B of Da < Db.

[0029] According to the second solution above, there is provided a toner for electrostatic image development, which has more excellent discharge property from the supply toner storage part as compared with the case where Da / Db is less than 1.0 or greater than 2.0.

[0030] According to the third solution above, there is provided a toner for electrostatic image development, which has more excellent discharge property from the supply toner storage part as compared with the case where the mass ratio Ma / Mb of the content Ma of the agglomerated silica particles A and the content Mb of the silica particles B is less than 0.5 or greater than 1.0.

[0031] According to the fourth solution above, there is provided a toner for electrostatic image development, which has more excellent discharge property from the supply toner storage part as compared with the case where the silica particles B are only fumed silica particles or only agglomerated silica particles.

[0032] According to the ninth solution above, there is provided a toner for electrostatic image development, which has more excellent discharge property from the supply toner storage part as compared with the case where the average particle diameter Da of the agglomerated silica particles A is less than 70 nm or greater than 110 nm.

[0033] According to the tenth solution above, there is provided a toner for electrostatic image development, which has more excellent discharge property from the supply toner storage part as compared with the case where the average particle diameter Db of the silica particles B is less than 20 nm or greater than 80 nm.

[0034] According to the eleventh solution above, there is provided a toner for electrostatic image development, which has more excellent discharge property from the supply toner storage part as compared with the case where the coverage rate of the agglomerated silica particles A on the toner particle surface is less than 5% or greater than 30%.

[0035] According to the twelfth solution above, there is provided a toner for electrostatic image development, which has more excellent discharge property from the supply toner storage part as compared with the case where the coverage rate of all the external additives on the toner particle surface is less than 60%.

[0036] According to the 13th aspect described above, there is provided a toner for electrostatic image development, which has more excellent discharge property from a supply toner storage part as compared with the case where the proportion included in the range of 20 nm or more and 100 nm or less in the number-based frequency distribution of the particle diameters of all external additives is less than 75%.

[0037] According to the 14th or 15th aspect described above, there is provided a toner for electrostatic image development, which has more excellent discharge property from a supply toner storage part as compared with the case where it does not contain tetrakis(trimethylsiloxy)silane.

[0038] According to the 16th aspect described above, there is provided an electrostatic image developer, which contains a toner for electrostatic image development. This toner for electrostatic image development has more excellent discharge property from a supply toner storage part as compared with a toner for electrostatic image development containing oil-treated aggregated silica particles A and silica particles B which are hydrophobicized by a treatment other than defatting treatment and can be either aggregated or non-aggregated, and having a relationship of average particle diameter Da of the aggregated silica particles A < average particle diameter Db of the silica particles B.

[0039] According to the 17th or 18th aspect described above, there is provided a toner cartridge. The toner cartridge according to the 17th or 18th aspect has more excellent discharge property of the toner for electrostatic image development as compared with a toner cartridge storing a toner for electrostatic image development containing oil-treated aggregated silica particles A and silica particles B which are hydrophobicized by a treatment other than defatting treatment and can be either aggregated or non-aggregated, and having a relationship of average particle diameter Da of the aggregated silica particles A < average particle diameter Db of the silica particles B.

[0040] According to the 19th aspect described above, there is provided a process cartridge. The toner for electrostatic image development according to the 19th aspect has more excellent discharge property from the toner cartridge as compared with the case where a toner for electrostatic image development containing oil-treated aggregated silica particles A and silica particles B which are hydrophobicized by a treatment other than defatting treatment and can be either aggregated or non-aggregated, and having a relationship of average particle diameter Da of the aggregated silica particles A < average particle diameter Db of the silica particles B is applied.

[0041] According to the 20th aspect described above, there is provided an image forming apparatus. The toner for electrostatic image development according to the 20th aspect has more excellent discharge property from a supply toner storage part as compared with the case where a toner for electrostatic image development containing oil-treated aggregated silica particles A and silica particles B which are hydrophobicized by a treatment other than defatting treatment and can be either aggregated or non-aggregated, and having a relationship of average particle diameter Da of the aggregated silica particles A < average particle diameter Db of the silica particles B is applied.

[0042] According to the 21st aspect described above, there is provided an image forming method. Compared with the case of an electrostatic image developing toner that uses aggregated silica particles A treated with oil and silica particles B that can be either aggregated or non-aggregated and are hydrophobized except for degreasing treatment, and the average particle diameter Da of the aggregated silica particles A and the average particle diameter Db of the silica particles B satisfy the relationship Da < Db, the electrostatic image developing toner of the 21st aspect has more excellent dischargeability from the replenishing toner storage unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 FIG. is a schematic configuration diagram showing an example of the toner cartridge of the present embodiment.

[0044] Figure 2 FIG. is a schematic configuration diagram showing an example of the processing cartridge of the present embodiment.

[0045] Figure 3 FIG. is a schematic configuration diagram showing an example of the image forming apparatus of the present embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0046] Embodiments of the present invention will be described below. These descriptions and examples are used to illustrate the embodiments and do not limit the scope of the embodiments.

[0047] In the present invention, the numerical range represented by "~" means a range that includes the values described before and after "~" as the minimum value and the maximum value, respectively.

[0048] In the numerical ranges described stepwise in the present invention, the upper limit value or the lower limit value described in one numerical range can be replaced with the upper limit value or the lower limit value of the other numerical range described in the other steps. In addition, in the numerical ranges described in the present invention, the upper limit value or the lower limit value of the numerical range can be replaced with the value shown in the examples.

[0049] The term "step" in the present invention includes not only independent steps but also, even when it cannot be clearly distinguished from other steps, as long as the desired purpose of the step can be achieved, it is also included in this term.

[0050] When describing the embodiments of the present invention with reference to the drawings, the configuration of the embodiment is not limited to the configuration shown in the drawings. In addition, the sizes of the components in each drawing are schematic, and the relative relationship of the sizes between the components is not limited thereto.

[0051] Each component in the present invention may include two or more corresponding substances. When referring to the amount of each component in the composition of the present invention, when there are two or more substances corresponding to each component in the composition, unless otherwise specified, it means the total amount of the two or more substances present in the composition.

[0052] The particles corresponding to each component in the present invention may include two or more types. When two or more types of particles corresponding to each component are present in the composition, the particle size of each component refers to the value for the mixture of the two or more types of particles present in the composition unless otherwise stated.

[0053] In the present invention, the “toner for developing an electrostatic image” is also simply referred to as the “toner”, and the “developer for developing an electrostatic image” is also simply referred to as the “developer”.

[0054] <Toner for Electrostatic Image Development>

[0055] The toner of this embodiment is supplied to an electrophotographic image forming apparatus as a replenishment toner to be supplied to a developing mechanism. The toner of this embodiment can also be used as a toner pre-loaded in a developing mechanism.

[0056] The toner of this embodiment includes toner particles, oil-treated agglomerated silica particles A, and silica particles B that have been subjected to a hydrophobic treatment other than oil removal treatment and may be either agglomerated or non-agglomerated. The relationship between the average particle size Da of the agglomerated silica particles A and the average particle size Db of the silica particles B is Da ≧ Db. Furthermore, the toner of this embodiment does not include any external additives other than the agglomerated silica particles A and B. Alternatively, even if it does include any external additives other than the agglomerated silica particles A and B, the average particle size of the external additives other than the agglomerated silica particles A and B is smaller than the average particle size Da of the agglomerated silica particles A.

[0057] The toner of this embodiment, due to the above-described configuration, exhibits excellent dischargeability from the replenishing toner storage unit within the image forming apparatus. The mechanism for this is presumed to be as follows. In the following description, the external additive other than the agglomerated silica particles A and silica particles B is referred to as "external additive C."

[0058] Toner adhering to the inner surface of a replenishing toner storage unit (e.g., a toner bottle) can reduce toner discharge efficiency. In particular, in rotary toner bottles, a spiral protrusion on the inner surface of the bottle typically moves toner toward the toner discharge port, with no other toner discharge mechanism (e.g., a propeller screw) inside the bottle. Therefore, toner adhering to the inner surface of the bottle significantly reduces toner discharge efficiency.

[0059] Therefore, in order to improve the discharge performance of toner from the replenishing toner storage portion, it is preferable to suppress the adhesion of toner to the inner surface of the replenishing toner storage portion.

[0060] Since the oil-treated agglomerated silica particles A are agglomerated silica particles, they have concave portions on their surface. Therefore, compared to non-oil-treated non-agglomerated silica particles, they have the following characteristics: (1) a large amount of oil on their surface; and (2) a greater number of contact points with the inner surface of the replenishing toner reservoir. Furthermore, since Da ≥ Db and the external additive C is absent or the average particle size of the external additive C is smaller than Da, the agglomerated silica particles A are the largest among the external additives, and thus form the outer edge of each toner.

[0061] Since the agglomerated silica particles A having the above-mentioned characteristics (1) and (2) form the outer edge of the toner, it is speculated that a relatively large amount of oil migrates from the agglomerated silica particles A to the inner surface of the replenishing toner storage portion, and it is speculated that the oil migrated to the inner surface of the replenishing toner storage portion will inhibit the toner from adhering to the inner surface of the replenishing toner storage portion.

[0062] If the silica particles used as the external additive are solely oil-treated, toner aggregation may be enhanced, potentially reducing the discharge efficiency of the replenished toner. In contrast, silica particles B, which are not oil-treated but have undergone a hydrophobic treatment other than oil treatment and have a Da ≥ Db relationship, are presumably formed by covering the toner particle surfaces in a manner that fills the spaces between the agglomerated silica particles A, thereby suppressing toner aggregation.

[0063] Presumably, due to the above-described mechanism, the toner of this embodiment can suppress adhesion to the inner surface of the replenishing toner storage portion and aggregation of toners, thereby achieving better discharge performance from the replenishing toner storage portion.

[0064] From the perspective of further optimizing the discharge performance of the toner from the replenishing toner storage portion, the agglomerated silica particles A and the silica particles B preferably satisfy a relationship of Da>Db.

[0065] From the perspective of further optimizing the discharge performance of the toner from the replenishing toner storage portion, the average particle size ratio Da / Db of the agglomerated silica particles A and the silica particles B is preferably greater than 1.0 and less than 2.0, more preferably greater than 1.0 and less than 2.0, and even more preferably greater than 1.2 and less than 1.8.

[0066] From the perspective of further optimizing the discharge performance of the toner from the replenishing toner storage portion, the mass basis ratio Ma / Mb of the content Ma of the agglomerated silica particles A to the content Mb of the silica particles B is preferably greater than or equal to 0.5 and less than or equal to 1.0, more preferably greater than or equal to 0.55 and less than or equal to 0.95, and even more preferably greater than or equal to 0.6 and less than or equal to 0.9.

[0067] The composition, structure, and characteristics of the toner according to this embodiment will be described in detail below.

[0068] [Toner particles]

[0069] The toner particles are composed of, for example, a binder resin and, if necessary, a colorant, a release agent, and other additives.

[0070] - Adhesive resin -

[0071] The toner particles preferably contain at least an amorphous resin and a crystalline polyester resin (referred to as a “specific crystalline polyester resin”) formed of a polycondensate of a linear dicarboxylic acid and a linear diol having 2 to 12 carbon atoms as a binding resin.

[0072] In the present invention, 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 15°C when measured at a heating rate of 10°C / min. The "amorphous" nature of a resin means that the resin has a half-width greater than 15°C, exhibits a step-like change in endothermic value, or lacks a clear endothermic peak.

[0073] The binder resin may contain other resins as needed. The total content of the amorphous resin and the specific crystalline polyester resin is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, relative to the total resins contained in the toner particles.

[0074] Amorphous polyester resin

[0075] Examples of the amorphous resin include amorphous polyester resins.

[0076] Examples of the amorphous polyester resin include polycondensates of polycarboxylic acids and polyols. A commercially available amorphous polyester resin may be used, or a synthetic amorphous polyester resin may be used.

[0077] Examples of polycarboxylic acids include aliphatic dicarboxylic acids (e.g., oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, alkenylsuccinic acid, adipic acid, and sebacic acid), alicyclic dicarboxylic acids (e.g., cyclohexanedicarboxylic acid), aromatic dicarboxylic acids (e.g., terephthalic acid, isophthalic acid, phthalic acid, and naphthalene dicarboxylic acid), anhydrides thereof, and lower (e.g., C1-5) alkyl esters thereof. Among these, aromatic dicarboxylic acids are preferred as polycarboxylic acids.

[0078] 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 trivalent or higher carboxylic acids include trimellitic acid, pyromellitic acid, their anhydrides, or their lower (e.g., C1-5) alkyl esters.

[0079] The polyvalent carboxylic acid may be used alone or in combination of two or more.

[0080] Examples of the polyol include aliphatic diols (e.g., ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, and neopentyl glycol), alicyclic diols (e.g., cyclohexanediol, cyclohexanedimethanol, and hydrogenated bisphenol A), and aromatic diols (e.g., ethylene oxide adducts of bisphenol A and propylene oxide adducts of bisphenol A). Among these, aromatic diols and alicyclic diols are preferred, and aromatic diols are more preferred.

[0081] As the polyol, a diol may be used in combination with a trivalent or higher polyol having a crosslinked structure or a branched structure. Examples of the trivalent or higher polyol include glycerin, trimethylolpropane, and pentaerythritol.

[0082] The polyols may be used alone or in combination of two or more.

[0083] The glass transition temperature (Tg) of the amorphous polyester resin is preferably 50°C or higher and 80°C or lower, and more preferably 50°C or higher and 65°C or lower.

[0084] The glass transition temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC), more specifically, by the "extrapolated glass transition onset temperature" method described in the glass transition temperature determination method in JIS K7121:1987 "Plastics - Determination of Transition Temperatures".

[0085] The weight average molecular weight (Mw) of the amorphous polyester resin is preferably 5,000 to 1,000,000, more preferably 7,000 to 500,000, and even more preferably 30,000 to 150,000.

[0086] The number average molecular weight (Mn) of the amorphous polyester resin is preferably 2,000 or more and 100,000 or less.

[0087] 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.

[0088] The weight-average molecular weight and number-average molecular weight were measured by gel permeation chromatography (GPC). Molecular weight measurements using GPC were performed using a Tosoh GPC HLC-8120GPC, a Tosoh TSKgel SuperHM-M (15 cm) column, and THF as a solvent. The weight-average molecular weight and number-average molecular weight were calculated from the measurement results using a molecular weight calibration curve prepared using monodisperse polystyrene standard samples.

[0089] The amorphous polyester resin is obtained by a known production method. Specifically, for example, the polymerization temperature is set at 180° C. to 230° C., and the pressure in the reaction system is reduced as needed to allow the reaction to proceed while removing water or alcohol generated during condensation.

[0090] If the raw monomers are insoluble or incompatible at the reaction temperature, a high-boiling-point solvent can be added as a dissolution aid to dissolve them. In this case, the polycondensation reaction is carried out while distilling off the dissolution aid. If a monomer with poor compatibility is present during the copolymerization reaction, the monomer with poor compatibility can be condensed with a specific acid or alcohol that is polycondensed with the monomer before polycondensation with the main component.

[0091] Crystalline polyester resin

[0092] 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.

[0093] Here, in order to facilitate the formation of a crystal structure of the crystalline polyester resin, a polycondensate obtained using a linear aliphatic polymerizable monomer is preferred over a polycondensate obtained using a polymerizable monomer having an aromatic ring.

[0094] Examples of the polycarboxylic acid include aliphatic dicarboxylic acids (e.g., oxalic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, etc.), aromatic dicarboxylic acids (e.g., dibasic acids such as phthalic acid, isophthalic acid, terephthalic acid, and naphthalene-2,6-dicarboxylic acid), anhydrides thereof, or lower (e.g., carbon number 1 to 5) alkyl esters thereof.

[0095] Among polycarboxylic acids, dicarboxylic acids may be used in combination with trivalent or higher carboxylic acids having a crosslinked structure or a branched structure. Examples of trivalent carboxylic acids include aromatic carboxylic acids (e.g., 1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, etc.), their anhydrides, or their lower (e.g., C1-5) alkyl esters.

[0096] As the polycarboxylic acid, these dicarboxylic acids can be used in combination with a dicarboxylic acid having a sulfonic acid group or a dicarboxylic acid having an ethylenic double bond.

[0097] The polyvalent carboxylic acid may be used alone or in combination of two or more.

[0098] Examples of the polyol include aliphatic diols (e.g., linear aliphatic diols having a main chain portion with 7 to 20 carbon atoms). Examples of the aliphatic diol include ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, and 1,14-eicosanediol. Among these, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferred.

[0099] Among the polyols, diols may be used in combination with trivalent or higher-valent alcohols having a cross-linked structure or a branched structure. Examples of the trivalent or higher-valent alcohols include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol.

[0100] The polyols may be used alone or in combination of two or more.

[0101] Here, the content of the aliphatic diol in the polyol is preferably 80 mol% or more, preferably 90 mol% or more.

[0102] 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.

[0103] The melting temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC) according to the “melting peak temperature” described in the method for measuring melting temperature in JIS K7121:1987 “Plastics - Determination of Transition Temperatures”.

[0104] The weight average molecular weight (Mw) of the crystalline polyester resin is preferably from 6,000 to 35,000, and more preferably from 7,000 to 15,000.

[0105] The crystalline polyester resin can be obtained, for example, by a known production method similar to the amorphous polyester.

[0106] The content of the binder resin relative to the entire toner particles is preferably 40% by mass or more and 95% by mass or less, more preferably 50% by mass or more and 90% by mass or less, and even more preferably 60% by mass or more and 85% by mass or less.

[0107] -Colorant-

[0108] 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, soluble blue, methylene blue chloride, phthalocyanine blue, pigment blue, phthalocyanine green, and malachite green oxalate; and dyes such as acridine-based, xanthene-based, azo-based, benzoquinone-based, azine-based, anthraquinone-based, thioindigo-based, dioxazine-based, thiazine-based, azomethine-based, indigo-based, phthalocyanine-based, nigrosine-based, polymethine-based, triphenylmethane-based, diphenylmethane-based, and thiazole-based dyes.

[0109] The coloring agents may be used alone or in combination of two or more.

[0110] The colorant may be surface-treated as needed, or may be used in combination with a dispersant. Furthermore, two or more colorants may be used in combination.

[0111] The content of the colorant is preferably from 1 mass % to 30 mass %, and more preferably from 3 mass % to 15 mass %, based on the total mass of the toner particles.

[0112] -Release agent-

[0113] Examples of release agents include hydrocarbon waxes, natural waxes such as carnauba wax, rice wax, and candelilla wax, synthetic waxes such as montan wax, and mineral / petroleum waxes, and ester waxes such as fatty acid esters and montanic acid esters. The release agent is not limited thereto.

[0114] The melting temperature of the release agent is preferably 50°C to 110°C, more preferably 60°C to 100°C.

[0115] The melting temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC) according to the “melting peak temperature” described in the method for measuring melting temperature in JIS K7121:1987 “Plastics - Determination of Transition Temperatures”.

[0116] The content of the release agent is preferably from 1 mass % to 20 mass %, and more preferably from 5 mass % to 15 mass %, based on the total amount of the toner particles.

[0117] -Other additives-

[0118] 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.

[0119] - Characteristics of toner particles, etc. -

[0120] The toner particles may be toner particles of a single-layer structure, or may be toner particles of a so-called core-shell structure composed of a core (core particle) and a coating layer (shell layer) covering the core.

[0121] The toner particles of a core-shell structure may be composed of, for example, a core portion comprising a binder resin and, if necessary, other additives such as a colorant and a release agent, and a coating layer comprising the binder resin.

[0122] The volume average particle diameter (D50v) of the toner particles is preferably 2 μm or more and 10 μm or less, and more preferably 4 μm or more and 8 μm or less.

[0123] Various average particle diameters and various particle size distribution indices of the toner particles are measured using Coulter Multisizer II (manufactured by Beckman Coulter) and ISOTON-II (manufactured by Beckman Coulter) for the electrolyte.

[0124] During measurement, 0.5 mg to 50 mg of the measurement sample is added to 2 ml of a 5% by mass aqueous solution of a surfactant (preferably sodium alkylbenzenesulfonate) as a dispersant, and this is added to 100 ml to 150 ml of the electrolyte.

[0125] The electrolyte solution containing the suspended sample was dispersed using an ultrasonic disperser for 1 minute, and the particle size distribution of particles with a diameter ranging from 2 μm to 60 μm was measured using a Coulter Multisizer II with an aperture of 100 μm. 50,000 particles were sampled.

[0126] Relative to the particle size range (interval) divided based on the measured particle size distribution, the volume and number are respectively drawn as cumulative distributions starting from the smaller diameter side, the particle size at the cumulative 16% point is defined as the volume particle size D16v and the number particle size D16p, the particle size at the cumulative 50% point is defined as the volume average particle size D50v and the cumulative number average particle size D50p, and the particle size at the cumulative 84% point is defined as the volume particle size D84v and the number particle size D84p.

[0127] Using these values, the volume particle size distribution index (GSDv) is calculated as (D84v / D16v) 1 / 2 Calculate the particle size distribution index (GSDp) by (D84p / D16p) 1 / 2 Calculated.

[0128] The average circularity of the toner particles is preferably from 0.94 to 1.00, and more preferably from 0.95 to 0.98.

[0129] [Agglomerated Silica Particles A]

[0130] Agglomerated silica particles A are oil-treated agglomerated silica particles.

[0131] Specific examples of the silica particles constituting the agglomerated silica particles A include fumed silica particles, wet-process silica particles, and fused silica particles.

[0132] The hydrophobizing agent for the agglomerated silica particles A is an oil. Examples of the oil include silicone oil, paraffin oil, fluorinated oil, and vegetable oil. One or more oils may be used. Among these, silicone oil is preferred, and dimethyl silicone oil is more preferred.

[0133] The oil treatment of the silica particles is performed, for example, by dissolving oil in alcohol and dispersing the silica particles therein, followed by distilling off the alcohol using an evaporator and drying the resulting particles.

[0134] Agglomerated silica particles A are preferably agglomerated particles of fumed silica particles because they have many concave portions serving as oil-retaining portions on the particle surface. Fumed silica particles can be produced, for example, by combusting silicon tetrachloride with hydrogen and oxygen.

[0135] The average particle diameter Da of the agglomerated silica particles A is preferably 70 nm or more and 110 nm or less. When the average particle diameter Da is 70 nm or more, the spacer effect of suppressing toner aggregation is excellent. From this perspective, the average particle diameter Da of the agglomerated silica particles A is more preferably 75 nm or more, and even more preferably 80 nm or more. When the average particle diameter Da is 110 nm or less, the agglomerated silica particles A are less likely to break. From this perspective, the average particle diameter Da of the agglomerated silica particles A is more preferably 105 nm or less, and even more preferably 100 nm or less.

[0136] The average particle size Da of the agglomerated silica particles A is determined by the following measuring method.

[0137] First, agglomerated silica particles are separated from the toner. This separation is achieved by exploiting the fact that agglomerated silica particles have weaker adhesion to toner particles than other external additives. For example, a dispersion of toner in water containing a surfactant is subjected to ultrasonic waves (65 μm, 1 minute, 20°C). The dispersion is then centrifuged at high speed, and the supernatant is dried at room temperature (23°C ± 2°C) to obtain agglomerated silica particles.

[0138] Next, the agglomerated silica particles are divided into oil-treated agglomerated silica particles (i.e., agglomerated silica particles A) and agglomerated silica particles that have undergone a hydrophobic treatment other than the oil treatment. For example, the agglomerated silica particles contained in the supernatant are washed with tetrahydrofuran (THF) and the difference in weight between the agglomerated silica particles before and after washing is used for identification. Assuming the weight before THF treatment is Wb and the weight after THF treatment is Wa, if (Wb - Wa) is 0.20% by mass or more of Wb, the agglomerated silica particles are identified as having been oil-treated.

[0139] The average particle size Da of the agglomerated silica particles A was determined by analyzing a scanning electron microscope (SEM) image, measuring the particle sizes (average of the major and minor diameters) of 500 agglomerated silica particles, and averaging the measured values.

[0140] An example embodiment of the agglomerated silica particles A includes an embodiment in which two peaks are present in the number-based frequency distribution of particle diameters, with the first peak being in the particle diameter range of 80 nm to 110 nm, and the second peak being in the particle diameter range of 50 nm to 80 nm. The agglomerated silica particles A in this embodiment are a mixture of first agglomerated silica particles (referred to as "agglomerated silica particles A1") having an average particle diameter of 80 nm to 110 nm, and second agglomerated silica particles (referred to as "agglomerated silica particles A2") having an average particle diameter of 50 nm to 80 nm.

[0141] The mixing ratio of the agglomerated silica particles A1 and the agglomerated silica particles A2 (based on mass, A1:A2) is preferably 20:80 to 70:30, more preferably 30:70 to 60:40, and even more preferably 40:60 to 50:50.

[0142] From the perspective of optimizing the discharge performance of the toner from the replenishing toner storage portion, the amount of agglomerated silica particles A added relative to the amount of toner particles is preferably not less than 0.1 mass % and not more than 4 mass %, more preferably not less than 0.3 mass % and not more than 2 mass %, and further preferably not less than 0.5 mass % and not more than 1 mass %.

[0143] From the perspective of optimizing the discharge performance of toner from the replenishing toner storage portion, the coverage of the toner particle surfaces with the aggregated silica particles A is preferably 5% to 30%, more preferably 8% to 28%, and even more preferably 10% to 25%.

[0144] The coverage of the toner particle surfaces with the aggregated silica particles A is determined by image analysis of an electron microscope image of the toner.

[0145] Specifically, the toner surface was observed in 100 fields at a magnification of 10,000x using a scanning electron microscope S-4700 (manufactured by Hitachi, Ltd.). The observed toner surface images were analyzed using the area analysis tool in the image processing and analysis software WinROOF (manufactured by Mitani Shoji Co., Ltd.). The coverage was calculated by calculating the area of the portion with attached agglomerated silica particles, the area of the portion with attached other external additives, and the area of the portion without attached external additives. Whether the particles were silica particles was determined by SEM-EDX. Agglomerated silica particles on oil-treated toner that were identified as agglomerated silica particles using the aforementioned method for measuring the average particle diameter Da can be referred to as agglomerated silica particles A.

[0146] [Silicon dioxide particles B]

[0147] Silica particles B are silica particles that have been subjected to a hydrophobic treatment other than oil treatment, and include both agglomerated silica particles and non-agglomerated silica particles. Silica particles B are silica particles that have not been subjected to an oil treatment.

[0148] The hydrophobizing agent for the silica particles B is not particularly limited as long as it is a treatment agent other than oil. Silazane compounds (e.g., dimethyldisilazane, trimethyldisilazane, tetramethyldisilazane, pentamethyldisilazane, hexamethyldisilazane, etc.) are preferred, with 1,1,1,3,3,3-hexamethyldisilazane (HMDS) being particularly preferred. These may be used alone or in combination of two or more.

[0149] From the perspective of suppressing toner aggregation, the silica particles B preferably have high roundness. Therefore, wet-process silica particles and non-agglomerated silica particles are preferred. The average roundness of the silica particles B is preferably 0.94 or greater. The roundness of the particles is calculated as 4π × (area of the particle image) ÷ (perimeter of the particle image). 1 / 2 , with a maximum value of 1, and the average roundness is determined by microscopic observation of at least 300 particles.

[0150] The silica particles B are more preferably non-agglomerated silica particles obtained by subjecting wet-process silica particles to a hydrophobicization treatment using 1,1,1,3,3,3-hexamethyldisilazane.

[0151] Wet-process silica particles can be obtained, for example, as follows.

[0152] Tetraalkoxysilane is added dropwise to an alkaline catalyst solution containing an alcohol compound and aqueous ammonia to hydrolyze and condense the tetraalkoxysilane, thereby obtaining a suspension containing sol-gel silica particles. The solvent is then removed from the suspension to obtain granules. The granules are then dried to obtain sol-gel silica particles. The average primary particle size of the sol-gel silica particles can be controlled by adjusting the amount of tetraalkoxysilane added relative to the amount of the alkaline catalyst solution.

[0153] The average particle diameter Db of the silica particles B is preferably 20 nm or more and 80 nm or less. When the average particle diameter Db is 20 nm or more, the silica particles B are less likely to be buried in the toner particles. For this reason, the average particle diameter Db of the silica particles B is more preferably 25 nm or more, and even more preferably 30 nm or more. When the average particle diameter Db is 80 nm or less, the silica particles B are less likely to roll on the toner particle surface and less likely to aggregate in recessed areas on the toner particle surface. For this reason, the average particle diameter Db of the silica particles B is more preferably 75 nm or less, and even more preferably 70 nm or less.

[0154] The average particle size Db of the silica particles B can be determined by the following measuring method.

[0155] First, agglomerated silica particles are separated from the toner. Separation of the agglomerated silica particles is achieved by utilizing the fact that the adhesion of the agglomerated silica particles to the toner particles is weaker than that of other external additives. For example, ultrasonic waves (65 μm, 1 minute, 20°C) are applied to a dispersion obtained by dispersing the toner in water containing a surfactant. The dispersion is then subjected to high-speed centrifugation, and the supernatant (1) is dried at room temperature (23°C ± 2°C) to obtain agglomerated silica particles.

[0156] Next, the agglomerated silica particles are divided into agglomerated silica particles that have been treated with oil (i.e., agglomerated silica particles A) and agglomerated silica particles that have been treated with hydrophobicity other than the oil treatment (i.e., agglomerated silica particles B). Regarding a method for distinguishing between the two, for example, the agglomerated silica particles contained in the supernatant (1) are washed with tetrahydrofuran (THF), and the difference in weight of the agglomerated silica particles before and after washing is used for discrimination. When the weight before THF treatment is defined as Wb and the weight after THF treatment is defined as Wa, if (Wb-Wa) is less than 0.20% by mass of Wb, it is determined that the agglomerated silica particles have not been treated with oil.

[0157] The average particle size of the agglomerated silica particles B was determined by analyzing a scanning electron microscope (SEM) image, measuring the particle sizes (average of the major and minor diameters) of 500 agglomerated silica particles, and averaging the measured values.

[0158] After the agglomerated silica particles are separated from the toner, the toner is further dispersed in water containing a surfactant and ultrasonic waves (160 μm, 60 min, 20° C.) are applied to the resulting dispersion. The dispersion is then centrifuged at high speed and the supernatant (2) is dried at room temperature (23° C.±2° C.) to obtain non-agglomerated silica particles.

[0159] Next, the non-agglomerated silica particles are divided into oil-treated non-agglomerated silica particles and non-agglomerated silica particles that have been subjected to a hydrophobic treatment other than the oil treatment (i.e., non-agglomerated silica particles B). Regarding a method for distinguishing between the two, for example, the non-agglomerated silica particles contained in the supernatant (2) are washed with THF, and the difference in weight of the non-agglomerated silica particles before and after washing is used for discrimination. When the weight before THF treatment is set as Wb and the weight after THF treatment is set as Wa, if (Wb-Wa) is less than 0.20% by mass of Wb, it is judged that the non-agglomerated silica particles have not been oil-treated.

[0160] The average particle size of the non-agglomerated silica particles B was determined by analyzing a scanning electron microscope (SEM) image, measuring the particle sizes (average of the major and minor diameters) of 500 silica particles, and averaging the measured values.

[0161] The average particle size Db of the silica particles B is obtained by weighting the average particle size of the agglomerated silica particles B and the average particle size of the non-agglomerated silica particles B in terms of number ratio.

[0162] The BET specific surface area of the silica particles B is preferably 100 m 2 / g above 240m 2 / g or less, more preferably 120m 2 / g above 220m 2 / g or less, more preferably 150m 2 / g above 200m 2 The BET specific surface area of the silica particles B is measured by a BET multipoint method using nitrogen gas.

[0163] From the perspective of optimizing the discharge performance of the toner from the replenishing toner storage portion, the amount of silica particles B added relative to the amount of toner particles is preferably not less than 0.1 mass % and not more than 5 mass %, more preferably not less than 0.3 mass % and not more than 3 mass %, and further preferably not less than 0.5 mass % and not more than 2 mass %.

[0164] [Other additives]

[0165] The toner of this embodiment does not contain any external additives other than the agglomerated silica particles A and the silica particles B, or even if it contains any external additives other than the agglomerated silica particles A and the silica particles B, the average particle size of the other external additives is smaller than the average particle size Da of the agglomerated silica particles A.

[0166] As other additives other than the agglomerated silica particles A and the silica particles B, for example, inorganic particles such as TiO2, Al2O3, CuO, ZnO, SnO2, CeO2, Fe2O3, MgO, BaO, CaO, K2O, Na2O, ZrO2, CaO·SiO2, K2O·(TiO2)n, Al2O3·2SiO2, CaCO3, MgCO3, BaSO4, and MgSO4 can be mentioned.

[0167] The surface of the inorganic particles as an external additive is preferably subjected to hydrophobization treatment. Hydrophobization treatment is carried out by, for example, immersing the inorganic particles in a hydrophobization treatment agent. The hydrophobization treatment agent is not particularly limited, and for example, silane coupling agents, silicone oils, titanate coupling agents, aluminum coupling agents, etc. can be enumerated. These treatment agents can be used alone or in combination with two or more. Typically, for example, relative to 100 mass parts of inorganic particles, the amount of the hydrophobization treatment agent is less than 10 mass parts by weight.

[0168] Other external additives besides the agglomerated silica particles A and the silica particles B include resin particles (resin particles such as polystyrene, polymethyl methacrylate, and melamine resin), detergent active agents (for example, metal salts of higher fatty acids represented by zinc stearate, and particles of fluorine-based high molecular weight bodies), etc.

[0169] When the toner of this embodiment contains external additives other than the agglomerated silica particles A and the silica particles B, the amount of the external additives added is preferably 0.01% by mass to 5% by mass, more preferably 0.01% by mass to 2.0% by mass, relative to the toner particles.

[0170] The toner of this embodiment may contain other external additives in addition to the agglomerated silica particles A and the silica particles B, but preferably does not contain other external additives.

[0171] From the perspective of optimizing the discharge performance of the toner from the replenishing toner storage portion, the total external additive coverage of the toner particle surface is preferably 60% to 100%, more preferably 70% to 100%, and even more preferably 80% to 100%.

[0172] The total external additive coverage of the toner particle surface is determined by the following measurement method.

[0173] (1) The toner is dispersed in an epoxy resin and allowed to cure overnight to prepare a measurement sample. For example, a two-component mixed epoxy resin may be used as the epoxy resin.

[0174] (2) A slice with a thickness of 100 nm was cut from the measurement sample using a microtome.

[0175] (3) The slice was placed on a copper grid and placed in a high-resolution electron microscope JEM-2010 (JEOL Ltd.) and photographed at a magnification of 500,000 times with an applied voltage of 200 kV.

[0176] (4) Enlarge the film to 3 to 10 times and print it.

[0177] (5) During printing using the process of (1) to (4), the surface of the toner particles with a diameter of 80% to 120% of the toner volume average particle size is observed, and the coating state of the toner particles with the external additive is evaluated. The coverage rate is calculated using the following formula.

[0178] Formula: Coverage rate = (covering length ÷ toner outer perimeter) × 100 (%)

[0179] Here, the coating length refers to the length of the external additive layer that is in direct contact with the surface of the toner particles.

[0180] In this embodiment, the average value of the coverage of ten toners is taken as the coverage.

[0181] From the perspective of optimizing the discharge performance of the toner from the replenishing toner storage unit, in the number-based frequency distribution of the particle sizes of all external additives, the proportion of particles in the range of 20 nm to 100 nm is preferably 75% to 100%, more preferably 80% to 100%, further preferably 85% to 100%, and even more preferably 90% to 100%.

[0182] [Low molecular weight siloxane with a molecular weight of 200 to 600]

[0183] The toner of this embodiment preferably contains a low-molecular-weight siloxane having a molecular weight of 200 to 600, which is composed only of a siloxane bond and an alkyl group.

[0184] Unless otherwise specified, the term "siloxane" in the present invention refers to siloxane consisting solely of siloxane bonds and alkyl groups. In the present invention, siloxanes with a molecular weight of less than 1000 fall within the category of low molecular weight siloxanes, while siloxanes with a molecular weight of 1000 or greater fall within the category of silicone oils.

[0185] It is preferred that a portion or all of the low molecular weight siloxane having a molecular weight of 200 to 600 is attached to a portion or all of the silica particles used as an external additive. When the silica particles are hydrophobic silica particles that have been subjected to a hydrophobic surface treatment, it is preferred that a portion or all of the low molecular weight siloxane having a molecular weight of 200 to 600 is attached to a portion or all of the hydrophobic silica particles.

[0186] It is presumed that the low-molecular-weight siloxane having a molecular weight of 200 to 600 plays a role in releasing oil on the surface of the aggregated silica particles A and causing the oil to migrate to the inner surface of the replenishing toner storage portion.

[0187] From the viewpoint of facilitating the migration of free oil, the molecular weight of the low-molecular-weight siloxane contained in the toner of this embodiment is preferably 200 or greater, more preferably 250 or greater, further preferably 280 or greater, and even more preferably 300 or greater.

[0188] Since silica particles tend to aggregate easily due to entanglement of siloxane molecules when the molecular weight is relatively large, the molecular weight of the low-molecular-weight siloxane contained in the toner of this embodiment is preferably 600 or less, more preferably 550 or less, further preferably 500 or less, and even more preferably 450 or less in order to suppress this phenomenon.

[0189] The toner of this embodiment may contain at least one selected from low molecular weight siloxanes with a molecular weight of less than 200, low molecular weight siloxanes with a molecular weight of greater than 600 and less than 1000, and silicone oils with a molecular weight of 1000 or greater, as long as the effects of the toner of this embodiment are not impaired.

[0190] In low-molecular-weight siloxanes having a molecular weight of 200 to 600, the number of Si atoms in one molecule is at least 2.

[0191] In low-molecular-weight siloxanes having a molecular weight of 200 to 600, the number of Si atoms in one molecule is preferably 3 or more, more preferably 4 or more, and even more preferably 5 or more, from the viewpoint of facilitating the migration of free oil.

[0192] In low-molecular-weight siloxanes having a molecular weight of 200 to 600, silica particles tend to aggregate due to entanglement between siloxane molecules. Therefore, to suppress this, the number of Si atoms in one molecule is preferably 7 or less, more preferably 6 or less, and even more preferably 5 or less.

[0193] From the above-mentioned two aspects, in the low molecular weight siloxane having a molecular weight of 200 to 600, the number of Si atoms in one molecule is particularly preferably 5.

[0194] From the perspective of facilitating the migration of free oil, the kinematic viscosity of low molecular weight siloxane with a molecular weight of 200 to 600 is preferably 2 mm at 25°C. 2 / s above 5mm 2 / s or less. The kinematic viscosity (mm) of the siloxane in this embodiment 2 The viscosity (in s) is a value obtained by dividing the viscosity at 25° C. measured using an Ostwald viscometer (a type of capillary viscometer) by the density.

[0195] An example of a low-molecular-weight siloxane having a molecular weight of 200 to 600 is a linear siloxane having an unbranched siloxane bond.

[0196] Examples of low molecular weight linear siloxanes having a molecular weight of 200 to 600 include hexaalkyldisiloxane, octaalkyltrisiloxane, decadecyltetrasiloxane, dodecylpentasiloxane, tetradecylhexasiloxane, and hexadecylheptasiloxane (wherein the molecular weight is 200 to 600).

[0197] Examples of the alkyl groups possessed by these low-molecular-weight linear siloxanes include linear alkyl groups having 1 to 10 carbon atoms (preferably 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms, and even more preferably 1 or 2 carbon atoms), branched alkyl groups having 3 to 10 carbon atoms (preferably 3 to 6 carbon atoms, more preferably 3 or 4 carbon atoms), and cyclic alkyl groups having 3 to 10 carbon atoms (preferably 3 to 6 carbon atoms, more preferably 3 or 4 carbon atoms). Of these, alkyl groups having 1 to 3 carbon atoms are preferred, with at least one of a methyl group and an ethyl group being preferred, and a methyl group being more preferred. The two or more alkyl groups possessed by a low-molecular-weight linear siloxane in one molecule may be the same or different.

[0198] Specific examples of the low-molecular linear siloxane having a molecular weight of 200 to 600 include octamethyltrisiloxane, decamethyltetrasiloxane, dodecamethylpentasiloxane, tetradecamethylhexasiloxane, and hexadecamethylheptasiloxane.

[0199] An example of a low-molecular-weight siloxane having a molecular weight of 200 to 600 is a branched-chain siloxane having a branched siloxane bond.

[0200] Examples of low-molecular-weight branched siloxanes having a molecular weight of 200 to 600 include branched siloxanes such as 1,1,1,3,5,5,5-heptadecyl-3-(trialkylsiloxy)trisiloxane, tetra(trialkylsiloxy)silane, and 1,1,1,3,5,5,7,7,7-nonadecyl-3-(trialkylsiloxy)tetrasiloxane (wherein the molecular weight is 200 to 600).

[0201] Examples of the alkyl groups contained in these low-molecular-weight branched siloxanes include linear alkyl groups having 1 to 10 carbon atoms (preferably 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms, and even more preferably 1 or 2 carbon atoms), branched alkyl groups having 3 to 10 carbon atoms (preferably 3 to 6 carbon atoms, more preferably 3 or 4 carbon atoms), and cyclic alkyl groups having 3 to 10 carbon atoms (preferably 3 to 6 carbon atoms, more preferably 3 or 4 carbon atoms). Of these, alkyl groups having 1 to 3 carbon atoms are preferred, with at least one of methyl and ethyl groups being preferred, and methyl being more preferred. The two or more alkyl groups contained in one molecule of the low-molecular-weight branched siloxane may be the same or different.

[0202] Specific examples of low molecular weight branched siloxanes having a molecular weight of 200 to 600 include methyltris(trimethylsiloxy)silane (molecular formula C 10 H 30 O3Si4), tetrakis(trimethylsiloxy)silane (molecular formula C 12 H 36 O4Si5), 1,1,1,3,5,5,7,7,7-nonamethyl-3-(trimethylsilyloxy)tetrasiloxane (molecular formula C 12 H 36 O4Si5).

[0203] An example of a low-molecular-weight siloxane having a molecular weight of 200 to 600 is a cyclic siloxane having a cyclic structure composed only of siloxane bonds.

[0204] Examples of low molecular weight cyclic siloxanes having a molecular weight of 200 to 600 include hexaalkylcyclotrisiloxane, octaalkylcyclotetrasiloxane, decadecylcyclopentasiloxane, dodecylcyclohexasiloxane, tetradecylcycloheptasiloxane, and hexadecylcyclooctasiloxane (wherein the molecular weight is 200 to 600).

[0205] Examples of the alkyl groups contained in these low molecular weight cyclic siloxanes include linear alkyl groups having 1 to 10 carbon atoms (preferably 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms, and even more preferably 1 or 2 carbon atoms), branched alkyl groups having 3 to 10 carbon atoms (preferably 3 to 6 carbon atoms, more preferably 3 or 4 carbon atoms), and cyclic alkyl groups having 3 to 10 carbon atoms (preferably 3 to 6 carbon atoms, more preferably 3 or 4 carbon atoms). Of these, alkyl groups having 1 to 3 carbon atoms are preferred, with at least one of a methyl group and an ethyl group being preferred, and a methyl group being more preferred. The two or more alkyl groups contained in one molecule of the low molecular weight cyclic siloxane may be the same or different.

[0206] Specific examples of the low-molecular-weight cyclic siloxane having a molecular weight of 200 to 600 include hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, tetradecamethylcycloheptasiloxane, and hexadecamethylcyclooctasiloxane.

[0207] As the low molecular weight siloxane having a molecular weight of 200 to 600, from the perspective of facilitating free oil migration, at least one selected from the group consisting of low molecular weight linear siloxanes and low molecular weight branched siloxanes is preferred. Low molecular weight branched siloxanes are more preferred, and low molecular weight siloxanes having a tetrakis structure are even more preferred. A tetrakis structured siloxane refers to a siloxane having at least one of the following structures (i.e., a tetrasiloxysilane structure) in its molecule.

[0208] [Chemistry 1]

[0209]

[0210] Examples of low molecular weight siloxanes with a molecular weight of 200 to 600 and a tetrakis(trialkylsiloxy)silane include, for example, linear alkyl groups having 1 to 10 carbon atoms (preferably 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms, and even more preferably 1 or 2 carbon atoms), branched alkyl groups having 3 to 10 carbon atoms (preferably 3 to 6 carbon atoms, more preferably 3 or 4 carbon atoms), and cyclic alkyl groups having 3 to 10 carbon atoms (preferably 3 to 6 carbon atoms, more preferably 3 or 4 carbon atoms). Of these, alkyl groups having 1 to 3 carbon atoms are preferred, with at least one of methyl and ethyl groups being preferred, and methyl being more preferred. The alkyl groups in a single molecule of a low molecular weight siloxane having a tetrakis(trialkylsiloxy)silane may be the same or different.

[0211] As the low-molecular-weight siloxane having a molecular weight of 200 to 600, tetrakis(trimethylsiloxy)silane is particularly preferred because it facilitates the migration of free oil.

[0212] From the perspective of facilitating the migration of free oil, the total content (by mass) of low molecular weight siloxanes having a molecular weight of 200 to 600 contained in the toner is preferably 0.01 ppm or more, more preferably 0.05 ppm or more, and even more preferably 0.1 ppm or more, relative to the mass of the toner.

[0213] Regarding the total content (by mass) of low-molecular-weight siloxanes having a molecular weight of 200 to 600 contained in the toner, since the silica particles are easily aggregated due to the entanglement of the siloxane molecules, from the perspective of suppressing this phenomenon, the total content is preferably 10 ppm or less, more preferably 5 ppm or less, further preferably 1 ppm or less, and even more preferably 0.5 ppm or less relative to the mass of the toner.

[0214] PPM is the abbreviation for parts per million.

[0215] The total content of low-molecular-weight siloxanes with a molecular weight of 200 to 600 contained in the toner was measured by the headspace method using a gas chromatograph-mass spectrometer (GCMS-QP2020, manufactured by Shimadzu Corporation) and a nonpolar column (Restek, Rtx-1, 10157, film thickness 1.00 μm, length 60 m, inner diameter 0.32 mm). The specific method is as follows.

[0216] The toner was weighed into a vial, sealed with a cap, and heated to 190° C. over 3 minutes. The volatile components in the vial were then introduced into a column to detect low molecular weight siloxanes with a molecular weight of 200 to 600 under the following conditions.

[0217] Carrier gas: Helium

[0218] Carrier gas pressure: 120kPa (constant pressure)

[0219] Oven temperature: 40°C (5 minutes) → (15°C / minute) → 250°C (6 minutes) (25 minutes total)

[0220] Ion source temperature: 260°C

[0221] Interface temperature: 260℃

[0222] A calibration curve was created using a standard solution of a reference substance (tetrakistrimethylsiloxysilane) diluted with ethanol to varying concentrations. The amount of low-molecular-weight siloxanes with a molecular weight of 200 to 600, as indicated by the peak area of the sample's chromatogram, was determined based on the calibration curve of the reference substance. If the sample's chromatogram showed two or more peaks corresponding to low-molecular-weight siloxanes with a molecular weight of 200 to 600, the total amount of these low-molecular-weight siloxanes was determined based on the sum of these peak areas and the calibration curve of the reference substance. Furthermore, the total content (ppm) of low-molecular-weight siloxanes with a molecular weight of 200 to 600 was calculated relative to the total amount of toner.

[0223] From the perspective of facilitating the migration of free oil, the total content (by mass) of low-molecular-weight siloxanes having a molecular weight of 200 to 600 contained in the toner is preferably 1 ppm or more, more preferably 5 ppm or more, further preferably 10 ppm or more, even more preferably 15 ppm or more, and even more preferably 20 ppm or more, relative to the total content of the agglomerated silica particles A and silica particles B contained in the toner.

[0224] Regarding the total content (mass basis) of low-molecular-weight siloxanes having a molecular weight of 200 to 600 contained in the toner, since silica particles are easily aggregated due to entanglement of siloxane molecules, from the perspective of suppressing this phenomenon, the total content of the agglomerated silica particles A and silica particles B contained in the toner is preferably 1000 ppm or less, more preferably 500 ppm or less, further preferably 200 ppm or less, further preferably 100 ppm or less, and further preferably 50 ppm or less.

[0225] The above-mentioned value is obtained by converting {the total content of low-molecular-weight siloxanes having a molecular weight of 200 to 600 contained in the toner / the total content of the aggregated silica particles A and the silica particles B contained in the toner} into parts per million.

[0226] The mass of the agglomerated silica particles A and the silica particles B refers to the mass of the silica particles after the hydrophobization treatment, and includes the mass of components derived from the hydrophobization agent.

[0227] The total content of the aggregated silica particles A and the silica particles B contained in the toner is determined by the following measurement method.

[0228] After the toner is dispersed in water containing a surfactant and ultrasonic waves are applied to the resulting dispersion, the dispersion is centrifuged at high speed, and the supernatant is dried at room temperature (23°C ± 2°C) to obtain agglomerated silica particles A and silica particles B. The agglomerated silica particles A and silica particles B obtained from the supernatant are weighed. Although low-molecular-weight siloxane may be attached to the surfaces of the agglomerated silica particles A and silica particles B obtained from the supernatant, the amount of the attached low-molecular-weight siloxane is negligible compared to the mass of the agglomerated silica particles A and silica particles B.

[0229] Low molecular weight siloxane with a molecular weight of 200 to 600 can be included in the toner by, for example, external addition to the toner particles; use as a surface treatment agent for agglomerated silica particles A or silica particles B (particularly silica particles B) which are external additives; and other methods.

[0230] [Toner Manufacturing Method]

[0231] The toner according to this embodiment is obtained by adding an external additive to the toner particles after producing the toner particles.

[0232] Toner particles can be produced by any of dry methods (e.g., kneading and pulverization methods) or wet methods (e.g., aggregation and coalescence methods, suspension polymerization methods, and dissolution and suspension methods). The method for producing toner particles is not particularly limited, and known methods can be employed. Among these, toner particles can be produced by the aggregation and coalescence method.

[0233] Specifically, for example, in the case of producing toner particles by an agglomeration and coalescence method, the toner particles are produced 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 and coalesce the agglomerated particles to form toner particles (fusion and coalescence step).

[0234] The details of each step are described below.

[0235] 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.

[0236] - Resin particle dispersion preparation step -

[0237] A resin particle dispersion in which resin particles serving 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.

[0238] The resin particle dispersion is prepared by, for example, dispersing the resin particles in a dispersion medium using a surfactant.

[0239] Examples of the dispersion medium used in the resin particle dispersion include aqueous media.

[0240] Examples of the aqueous medium include water such as distilled water and ion-exchanged water, and alcohols. These media may be used alone or in combination of two or more.

[0241] Examples of surfactants include anionic surfactants such as sulfate esters, sulfonates, phosphates, and soaps; cationic surfactants such as amine salts and quaternary ammonium salts; and nonionic surfactants such as polyethylene glycols, alkylphenol ethylene oxide adducts, and polyols. Among these, anionic surfactants and cationic surfactants are particularly useful. Nonionic surfactants can be used in combination with anionic or cationic surfactants.

[0242] The surfactant may be used alone or in combination of two or more.

[0243] In the resin particle dispersion, as a method for dispersing the resin particles in the dispersion medium, for example, common dispersion methods 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 the form of particles.

[0244] 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 even more preferably 0.1 μm or more and 0.6 μm or less.

[0245] The volume average particle size of the resin particles is determined using a particle size distribution obtained by measurement using a laser diffraction particle size analyzer (e.g., LA-700 manufactured by Horiba, Ltd.). For the defined particle size range (interval), a cumulative distribution is plotted with respect to volume, starting from the smaller particle size side. The particle size at the cumulative 50% point relative to all particles is measured, and this particle size is defined as the volume average particle size D50v. The volume average particle size of particles in other dispersions is measured in the same manner.

[0246] The content of the resin particles contained in the resin particle dispersion is preferably from 5% by mass to 50% by mass, and more preferably from 10% by mass to 40% by mass.

[0247] For example, a colorant particle dispersion and a release agent particle dispersion are prepared in the same manner as the resin particle dispersion. Specifically, the volume average particle size, dispersion medium, dispersion method, and particle content of the particles in the resin particle dispersion are the same for the colorant particles dispersed in the colorant particle dispersion and the release agent particles dispersed in the release agent particle dispersion.

[0248] - Agglomerated Particle Formation Step-

[0249] Next, the resin particle dispersion, the colorant particle dispersion, and the release agent particle dispersion are mixed.

[0250] Thereafter, 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.

[0251] Specifically, for example, a coagulant is added to the mixed dispersion, and the pH of the mixed dispersion is adjusted to acidic (for example, pH 2 or higher and pH 5 or lower), 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 not less than -30°C and the glass transition temperature is not more than -10°C), so that the particles dispersed in the mixed dispersion are agglomerated to form agglomerated particles.

[0252] In the aggregated particle formation step, for example, a coagulant can be added to the mixed dispersion at room temperature (e.g., 25° C.) while stirring the mixed dispersion using a rotary shearing homogenizer, the pH of the mixed dispersion can be adjusted to acidic (e.g., pH 2 to 5), and a dispersion stabilizer can be added as needed, followed by heating.

[0253] Examples of the coagulant include surfactants with 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 charging characteristics are improved.

[0254] If necessary, an additive that forms a complex or similar bond with the metal ion of the coagulant can be used together with the coagulant. As such an additive, a chelating agent is preferably used.

[0255] Examples of the inorganic metal salt include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate; and inorganic metal salt polymers such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide.

[0256] 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.

[0257] 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, relative to 100 parts by mass of the resin particles.

[0258] - Fusion and coalescence step -

[0259] Next, the aggregated particle dispersion containing the dispersed aggregated particles is heated to a temperature equal to or higher than the glass transition temperature of the resin particles (e.g., 10°C to 30°C higher than the glass transition temperature of the resin particles) to fuse and coalesce the aggregated particles to form toner particles.

[0260] After the above steps, toner particles are obtained.

[0261] After obtaining a dispersion of aggregated particles in which aggregated particles are dispersed, colorant particles can be manufactured by the following steps: further mixing the aggregated particle dispersion with a resin particle dispersion in which resin particles are dispersed, and agglomerating the resin particles so as to further adhere to the surface of the aggregated particles to form second aggregated particles; and heating the second aggregated particle dispersion in which the second aggregated particles are dispersed to fuse and aggregate the second aggregated particles to form colorant particles with a core-shell structure.

[0262] After the fusion and coalescence steps are completed, the toner particles formed in the solution are subjected to known washing, solid-liquid separation, and drying steps to obtain dry toner particles. For the washing step, displacement washing using ion-exchanged water is suitable for charging performance. For the solid-liquid separation step, suction filtration, pressure filtration, etc. are suitable for productivity. For the drying step, freeze drying, airflow drying, fluidized bed drying, vibrating fluidized bed drying, etc. are suitable for productivity.

[0263] The toner of this embodiment is then produced by, for example, adding an external additive to the resulting dried toner particles and mixing them. Mixing can be performed using, for example, a V-blender, Henschel mixer, or Loedige mixer. Furthermore, if necessary, coarse toner particles can be removed using a vibrating screen or pneumatic screen.

[0264] <Electrostatic Image Developer>

[0265] The electrostatic image developer according to the present embodiment includes at least the toner according to the present embodiment.

[0266] The electrostatic image developer of the present embodiment may be a one-component developer containing only the toner of the present embodiment, or a two-component developer in which the toner is mixed with a carrier.

[0267] The carrier is not particularly limited, and known carriers can be used. Examples of carriers include coated carriers in which a core material composed of magnetic powder is coated with a resin; magnetic powder-dispersed carriers in which magnetic powder is dispersed and mixed in a matrix resin; and resin-impregnated carriers in which porous magnetic powder is impregnated with a resin. Magnetic powder-dispersed carriers and resin-impregnated carriers may be carriers in which the constituent particles of the carrier serve as a core material and are coated with a resin.

[0268] Examples of the magnetic powder include magnetic metals such as iron, nickel, and cobalt; and magnetic oxides such as ferrite and magnetite.

[0269] 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, straight silicone resin containing an organosiloxane bond or its modified form, fluororesin, polyester, polycarbonate, phenol resin, epoxy resin, and the like. 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.

[0270] When utilizing the surface of the resin coating core material, can cite the method etc. of coating with the coating layer formation solution that utilizes coating resin and various additives (used as needed) dissolved in appropriate solvent.As solvent, there is no particular limitation, consider the kind of resin used, coating suitability etc. and select and get final product.

[0271] 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 the solvent is then removed; and the like.

[0272] 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, more preferably 3:100 to 20:100.

[0273] <Toner Cartridge>

[0274] The toner cartridge of this embodiment stores the toner of this embodiment and is attached to and detached from an image forming apparatus. The toner cartridge stores replenished toner for supply to a developing mechanism provided in the image forming apparatus.

[0275] One embodiment of the toner cartridge according to the present embodiment is a rotary toner cartridge in which a main body storing toner rotates. Figure 1 This is a schematic structural diagram showing a rotary toner bottle as an example of a rotary toner cartridge. Figure 1 The illustrated rotary toner bottle 200 includes a bottle body 202 , a cap 204 , and a gear 206 .

[0276] The bottle body 202 is cylindrical and has a concave-convex portion 220 on the side for moving the replenishing toner toward the discharge port. The convex portion 210 provided on the concave-convex portion 220 is continuously arranged in a spiral from near the bottom surface of the bottle body 202 toward the cover 204. The convex portion 210 is arranged in a manner that appears convex when viewed from the inside of the bottle body 202. The convex portion 210 can be a single spiral or two or more spirals. When viewed from the inside of the bottle body 202, the portion sandwiched by adjacent convex portions 210 appears concave. In order to facilitate the movement of the replenishing toner toward the cover 204 inside the bottle body 202, it is preferred that the width of the convex portion 210 (the length in the direction of the axis Q) is narrower than the width of the adjacent concave portion (the length in the direction of the axis Q).

[0277] The bottle body 202 is made of, for example, resin. Examples of the material of the bottle body 202 include polyethylene terephthalate, polyolefin, and polyester. The bottle body 202 and the gear 206 may be integrally molded, or they may be molded separately and combined into separate molded products.

[0278] The cap 204 is provided at one end of the rotary toner bottle 200 in the direction of the axis Q. The cap 204 is provided with a discharge port 209 for discharging replenishment toner and a shutter 208 for opening and closing the discharge port 209. The discharge port 209 is opened and closed by opening and closing the shutter 208.

[0279] The gear 206 is a gear (or wheel) that meshes with a drive gear provided in the toner cartridge mounting portion when the rotary toner bottle 200 is mounted in the toner cartridge mounting portion of the image forming apparatus and is driven by the drive gear. The gear 206 is provided concentrically with the bottle body 202 . Figure 1 The outer diameter of the gear 206 shown in the figure is smaller than the outer diameter of the bottle body 202. The outer diameter of the gear 206 may be the same as the outer diameter of the bottle body 202, or may be larger than the outer diameter of the bottle body 202.

[0280] Figure 1, the bottle body 202 is provided with the concave-convex portion 220, but the toner cartridge and the rotary toner bottle of this embodiment are not limited thereto. When viewed from the outside of the bottle body 202, the side surface of the bottle body 202 may be a flat curved surface without a concave portion.

[0281] in addition, Figure 1 , the convex portion 210 is shown as a part of the bottle body 202. However, the toner cartridge and the rotary toner bottle of this embodiment are not limited to this. The convex portion 210 may also be a component separate from the bottle body 202. For example, a coil-shaped component that is provided in contact with the inner surface of the bottle body 202 and spirally extends from near the bottom surface of the bottle body 202 toward the cap 204 can be used as a separate component.

[0282] The width of the protrusion 210 (the length in the direction of the axis Q) is, for example, 3 mm to 20 mm, preferably 8 mm to 14 mm. The height of the protrusion 210 is, for example, 5 mm to 20 mm, preferably 5 mm to 15 mm. The helical period of the protrusion 210 (the distance in the direction of the axis Q) is, for example, 10 mm to 70 mm, preferably 25 mm to 55 mm.

[0283] Next, an operation of mounting the rotary toner bottle 200 on the toner cartridge mounting portion of the image forming apparatus will be described.

[0284] The rotary toner bottle 200 is mounted on the toner cartridge mounting portion such that the gear 206 meshes with the drive gear of the toner cartridge mounting portion. At this point, the shutter 208 is opened, connecting the rotary toner bottle 200 to the toner supply path of the image forming device via the discharge port 209. By rotating the drive gear of the toner cartridge mounting portion, the gear 206 is driven to rotate, and the bottle body 202 is driven to rotate about the axis Q. The driven rotation of the bottle body 202 causes the replenishing toner to move from the bottom surface of the bottle body 202 toward the cover 204 via the concave-convex portion 220. The replenishing toner moved toward the cover 204 is discharged from the discharge port 209 and supplied to the toner supply path of the image forming device. The rotary toner bottle 200 is mounted on the toner cartridge mounting portion of the image forming device, for example, so that the axis Q is horizontal.

[0285] <Processing cartridge>

[0286] The processing box of this embodiment is a processing box that is loaded and unloaded in an image forming device, and is equipped with: a developing mechanism that stores an electrostatic image developer and uses the electrostatic image developer to develop the electrostatic image formed on the surface of the image retaining body into a toner image; a toner box that stores the toner for electrostatic image development of this embodiment; and a toner supply path that connects the toner box and the developing mechanism and supplies the toner for electrostatic image development in the toner box to the developing mechanism.

[0287] The process cartridge of this embodiment may include a developing mechanism, a toner cartridge, a toner supply path, and, if necessary, at least one selected from an image holding member, a charging mechanism, an electrostatic image forming mechanism, a transfer mechanism, and the like.

[0288] An example of the process cartridge according to the present embodiment is shown below, but the present embodiment is not limited thereto.

[0289] Figure 2 This is a schematic structural diagram showing an example of the process cartridge according to the present embodiment. Figure 2 The process cartridge 300 shown is mounted and dismounted, for example, Figure 3 In the image forming apparatus shown.

[0290] The process cartridge 300 includes a developing device 104 (an example of a developing mechanism), a toner supply passage 108 , and a toner cartridge 200 . Figure 2 1 and 2 also illustrate a photoreceptor 102 (an example of an image holding member) disposed around the process cartridge 300 when the process cartridge 300 is installed in the image forming apparatus.

[0291] The developing device 104 is divided into two chambers, for example, by a partition. One chamber is provided with an outlet for the toner supply passage 108, and the other chamber is provided with a developing roller facing the photoreceptor 102. The two chambers are partially connected, and each chamber includes a stirring member for stirring and conveying the developer. The developer (not shown) within the developing device 104 is stirred and conveyed by the two stirring members and then supplied to the developing roller.

[0292] One end of the toner supply passage 108 is connected to the toner cartridge mounting portion 106, and the other end is connected to the developing device 104. An augerscrew 110, an example of a toner transport member, is disposed within the toner supply passage 108. The rotation of the augerscrew 110 causes toner to flow through the toner supply passage 108. Alternatively, the toner supply passage 108 may not include a toner transport member such as an augerscrew. In this case, the toner flows through the toner supply passage 108 by, for example, free fall.

[0293] The toner cartridge mounting portion 106 is used to detachably mount the toner cartridge 200 in the image forming apparatus. A toner receiving port communicating with a toner discharge port of the toner cartridge 200 and a rotating member (eg, a gear) for rotating the toner cartridge 200 are provided in the toner cartridge mounting portion 106 .

[0294] The toner cartridge 200 internally stores the electrostatic image developing toner of this embodiment as replenishment toner for supplying to the developing device 104. The toner cartridge 200 is, for example, a rotary toner bottle (an example of a toner cartridge) and includes a bottle body 202, a cap 204, a gear 206, and a shutter 208 for opening and closing a toner discharge port. The specific configuration and preferred configurations of the toner cartridge 200 are the same as those of the rotary toner bottle 200 described above.

[0295] The toner cartridge 200 is mounted on the toner cartridge mounting portion 106 with its longitudinal axis oriented in the horizontal direction, for example. A rotating member (eg, a gear) included in the toner cartridge 106 rotates the toner cartridge 200 about a horizontal axis, for example.

[0296] <Image Forming Apparatus, Image Forming Method>

[0297] The image forming device of this embodiment includes: 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 uses the electrostatic image developer to develop the electrostatic image formed on the surface of the image holder into a toner image; a transfer mechanism that transfers the toner image formed on the surface of the image holder to the surface of the recording medium; a fixing mechanism that fixes the toner image transferred to the surface of the recording medium; a replenishing toner storage section, which is a replenishing toner storage section that stores the replenishing toner supplied to the developing mechanism, and stores the electrostatic image developing toner of this embodiment; and a toner supply path that connects the replenishing toner storage section and the developing mechanism, and supplies the electrostatic image developing toner in the replenishing toner storage section to the developing mechanism.

[0298] The image forming device of the present embodiment implements an image forming method (the image forming method of the present embodiment), which has the following steps: a charging step of charging the surface of the image retaining body; an electrostatic image forming step of forming an electrostatic image on the charged surface of the image retaining body; a developing step of developing the electrostatic image formed on the surface of the image retaining body into a toner image using the electrostatic image developer of the present embodiment; a transfer step of transferring the toner image formed on the surface of the image retaining body to the surface of the recording medium; a fixing step of fixing the toner image transferred to the surface of the recording medium; and a toner replenishing step of replenishing the electrostatic image developing toner in the replenishing toner storage part from a replenishing toner storage part storing the electrostatic image developing toner of the present embodiment to the developing mechanism through a toner replenishing path connecting the replenishing toner storage part and the developing mechanism.

[0299] The image forming device of this embodiment is applicable to the following well-known image forming devices: a device using a direct transfer method for directly transferring a toner image formed on the surface of an image retaining body to a recording medium; a device using an intermediate transfer method for transferring a toner image formed on the surface of an image retaining body to the surface of an intermediate transfer body for the first time, and transferring the toner image transferred to the surface of the intermediate transfer body to the surface of a recording medium for the second time; a device having a cleaning mechanism for cleaning the surface of an image retaining body after the toner image is transferred and before charging; a device having a static elimination mechanism for eliminating static by irradiating the surface of an image retaining body with static elimination light after the toner image is transferred and before charging; and the like.

[0300] When the image forming device of this embodiment is an intermediate transfer type device, the transfer mechanism used is, for example, a structure having the following components: an intermediate transfer body to the surface of which the toner image is transferred; a primary transfer mechanism that transfers the toner image formed on the surface of the image retaining body to the surface of the intermediate transfer body for the first time; and 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 for the second time.

[0301] In the image forming apparatus of this embodiment, the portion including the developing mechanism may be a cartridge structure (process cartridge) that is detachably mounted in the image forming apparatus. For example, a process cartridge that stores the electrostatic image developer of this embodiment and includes a developing mechanism may be used.

[0302] 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 parts are omitted.

[0303] Figure 3 2 is a diagram schematically showing the configuration of the image forming apparatus according to this embodiment.

[0304] Figure 3The image forming apparatus shown includes first to fourth electrophotographic image forming units 10Y, 10M, 10C, and 10K (image forming mechanisms) that output images of yellow (Y), magenta (M), cyan (C), and black (K) based on color-separated image data. These image forming units (hereinafter sometimes referred to as "units") 10Y, 10M, 10C, and 10K are arranged in parallel horizontally, spaced a predetermined distance apart from one another. These units 10Y, 10M, 10C, and 10K may be process cartridges that are attachable to and detachable from the image forming apparatus.

[0305] An intermediate transfer belt (an example of an intermediate transfer member) 20 is installed above each unit 10Y, 10M, 10C, and 10K, extending through each unit. The intermediate transfer belt 20 is wound around a drive roller 22 and a support roller 24, traveling from the first unit 10Y toward the fourth unit 10K. The support roller 24 is biased away from the drive roller 22 by a spring (not shown), thereby applying tension to the intermediate transfer belt 20 wound between the drive roller 22 and the support roller 24. An intermediate transfer member cleaning device 30 is provided on the image holder side of the intermediate transfer belt 20, facing the drive roller 22.

[0306] Figure 3 The image forming apparatus shown has a configuration in which toner cartridges 8Y, 8M, 8C, and 8K are detachably mounted as an example of a toner storage unit for replenishment. The developing devices 4Y, 4M, 4C, and 4K of the units 10Y, 10M, 10C, and 10K are connected to the toner cartridges 8Y, 8M, 8C, and 8K, respectively, via toner replenishment paths (not shown). Toner of each color is replenished from the toner cartridges 8Y, 8M, 8C, and 8K via the toner replenishment paths. When the toner stored in the toner cartridges is low, the toner cartridges are replaced.

[0307] Since the first to fourth units 10Y, 10M, 10C, and 10K have the same configuration and operation, the first unit 10Y disposed upstream in the traveling direction of the intermediate transfer belt and forming a yellow image will be described as a representative example.

[0308] The first unit 10Y includes a photoreceptor 1Y, which functions as an image holder. Sequentially arranged around the photoreceptor 1Y are: a charging roller (an example of a charging mechanism) 2Y, which charges the surface of the photoreceptor 1Y to a predetermined potential; an exposure device (an example of an electrostatic image forming mechanism) 3, which exposes the charged surface using laser light 3Y based on a color separation image signal to form an electrostatic image; a developing device (an example of a developing mechanism) 4Y, which supplies the charged toner to the electrostatic image to develop it; a primary transfer roller 5Y (an example of a primary transfer mechanism), which transfers the developed toner image to the intermediate transfer belt 20; and a photoreceptor cleaning device (an example of a cleaning unit) 6Y, which removes toner remaining on the surface of the photoreceptor 1Y after the primary transfer.

[0309] The primary transfer roller 5Y is disposed inside the intermediate transfer belt 20, positioned opposite the photoreceptor 1Y. Each of the primary transfer rollers 5Y, 5M, 5C, and 5K in each unit is connected to a bias power supply (not shown) for applying a primary transfer bias. Each bias power supply is controlled by a control unit (not shown) to change the value of the transfer bias applied to each primary transfer roller.

[0310] Next, the operation of forming a yellow image in the first unit 10Y will be described.

[0311] First, before operation, the surface of the photoreceptor 1Y is charged to a potential of -600V to -800V by the charging roller 2Y.

[0312] The photoreceptor 1Y has a conductivity (e.g., a volume resistivity of 1×10 -6 The photosensitive layer is formed by laminating a photosensitive layer on a substrate (with a resistance of Ωcm or less). This photosensitive layer normally has a high electrical resistance (commonly seen in resins), but when irradiated with laser light, the resistivity of the portion exposed to the laser light changes. Therefore, based on yellow image data sent from a control unit (not shown), laser light 3Y is irradiated from exposure device 3 onto the charged surface of photoreceptor 1Y. This forms an electrostatic image of a yellow image pattern on the surface of photoreceptor 1Y.

[0313] 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 by the laser beam 3Y remains, thereby forming the negative latent image.

[0314] The electrostatic image formed on the photoreceptor 1Y rotates to a predetermined development position as the photoreceptor 1Y travels. At the development position, the electrostatic image on the photoreceptor 1Y is developed into a toner image by the developing device 4Y and visualized.

[0315] The developing device 4Y stores an electrostatic image developer, for example, containing at least yellow toner and a carrier. The yellow toner is triboelectrically charged by agitation within the developing device 4Y, acquiring a charge of the same polarity (negative) as the charge on the photoreceptor 1Y and being retained on the developer roller (an example of a developer retainer). The yellow toner then passes through the developing device 4Y on the surface of the photoreceptor 1Y, where it electrostatically adheres to the de-electrified latent image on the surface of the photoreceptor 1Y, developing the latent image with the yellow toner. The photoreceptor 1Y, bearing the yellow toner image, continues to operate at a predetermined speed, transferring the developed toner image on the photoreceptor 1Y to a predetermined primary transfer position.

[0316] 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. The electrostatic force from the photoreceptor 1Y toward the primary transfer roller 5Y acts on the toner image, transferring the toner image on the photoreceptor 1Y to the intermediate transfer belt 20. The transfer bias applied at this time has a polarity (+) opposite to the polarity (-) of the toner and is controlled by a control unit (not shown) in the first unit 10Y to, for example, +10 μA.

[0317] On the other hand, the toner remaining on the photoreceptor 1Y is removed and recovered by the photoreceptor cleaning device 6Y.

[0318] The primary transfer bias applied to the primary transfer rollers 5M, 5C, and 5K in and after the second unit 10M is also controlled in accordance with the first unit.

[0319] In this manner, the intermediate transfer belt 20 to which the yellow toner image has been transferred by the first unit 10Y is sequentially conveyed through the second to fourth units 10M, 10C, and 10K, so that the toner images of the respective colors are multiply transferred in a superimposed manner.

[0320] After passing through the first through fourth units and having multiple-transferred four-color toner images, the intermediate transfer belt 20 reaches the secondary transfer section. This section consists of the intermediate transfer belt 20, a backup roller 24 in contact with the inner surface of the intermediate transfer belt, and a secondary transfer roller (an example of a secondary transfer mechanism) 26 positioned on the image-holding side of the intermediate transfer belt 20. Meanwhile, recording paper (an example of recording medium) P is fed by a feeding mechanism at a predetermined timing to the gap between the secondary transfer roller 26 and the intermediate transfer belt 20. A secondary transfer bias is applied to the backup roller 24. The applied transfer bias has the same (-) polarity as the toner (-). Electrostatic force from the intermediate transfer belt 20 toward the recording paper P acts on the toner image, transferring the toner image from the intermediate transfer belt 20 to the recording paper P. The secondary transfer bias is determined based on the resistance detected by a resistance detection mechanism (not shown) that detects the resistance of the secondary transfer section, and the voltage is controlled accordingly.

[0321] Thereafter, the recording paper P is fed into a pressure-contact portion (nip portion) of a pair of fixing rollers in a fixing device (an example of a fixing mechanism) 28 , whereby the toner image is fixed to the recording paper P to form a fixed image.

[0322] Examples of the recording paper P to which the toner image is transferred include plain paper used in electrophotographic copy machines, printers, etc. Examples of the recording medium include, in addition to the recording paper P, OHP transparent films and the like.

[0323] To further improve the smoothness of the image surface after fixing, the surface of the recording paper P is preferably smooth. For example, coated paper obtained by coating the surface of plain paper with resin or the like, or art paper for printing, is suitable.

[0324] The recording paper P on which the color image has been fixed is fed to the discharge portion, completing a series of color image forming operations.

[0325] [Example]

[0326] The following examples illustrate embodiments of the present invention in detail, but the present invention is not limited to these examples. In the following description, "parts" and "%" are based on mass unless otherwise specified.

[0327] <Production of Toner Particles (1)>

[0328] [Preparation of Polyester Resin Particle Dispersion (1)]

[0329] Ethylene glycol: 37 parts

[0330] Neopentyl glycol: 65 parts

[0331] 1,9-nonanediol: 32 parts

[0332] Terephthalic acid: 96 parts

[0333] The above materials were placed in a flask, and the temperature was raised to 200°C over 1 hour. The reaction system was stirred, and after confirming this, 1.2 parts of dibutyltin oxide was added. While distilling off the generated water, the temperature was raised from the above temperature to 240°C over 6 hours. A dehydration condensation reaction was continued at 240°C for 4 hours to obtain a polyester resin (1) having an acid value of 9.4 mgKOH / g, a weight-average molecular weight of 13,000, and a glass transition temperature of 62°C.

[0334] The polyester resin (1) was kept in a molten state and fed into a Cavitron CD1010 (manufactured by Eurotec) at a rate of 100 parts per minute. A separately prepared 0.37% dilute ammonia solution was heated to 120°C using a heat exchanger and fed into the Cavitron CD1010 at a rate of 0.1 liter per minute together with the polyester resin (1). The rotor was rotated at a speed of 60 Hz and a pressure of 5 kg / cm 2 Cavitron CD1010 was operated under the conditions of , to obtain a polyester resin particle dispersion (1) having a solid content of 30% by mass. The volume average particle size of the resin particles contained in the polyester resin particle dispersion (1) was 160 nm.

[0335] [Preparation of Colorant Particle Dispersion (1)]

[0336] Cyan pigment (copper phthalocyanine, CI Pigment Blue 15:3, manufactured by Dainichi Seika Co., Ltd.): 10 parts

[0337] Anionic surfactant (NEOGEN SC, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.): 2 parts

[0338] Ion exchange water: 80 parts

[0339] The above materials were mixed and dispersed for 1 hour using a high-pressure impact disperser (HJP30006, manufactured by Sugino Machine Co., Ltd.) to obtain a colorant particle dispersion (1) having a solid content of 20% by mass. The volume average particle size of the colorant particles contained in the colorant particle dispersion (1) was 180 nm.

[0340] [Preparation of Release Agent Particle Dispersion (1)]

[0341] Carnauba wax (RC-160, melting temperature 84°C, manufactured by Toa Chemical Co., Ltd.): 50 parts

[0342] Anionic surfactant (NEOGEN SC, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.): 2 parts

[0343] Ion exchange water: 200 parts

[0344] The above materials were heated to 120°C and dispersed using an ULTRA-TURRAXT50 manufactured by IKA, followed by a pressure-dispensing Gaulin homogenizer to obtain a release agent particle dispersion (1) having a solid content of 20% by mass. The release agent particles contained in the release agent particle dispersion (1) had a volume average particle size of 200 nm.

[0345] [Production of Toner Particles]

[0346] Polyester resin particle dispersion (1): 200 parts

[0347] Colorant particle dispersion (1): 25 parts

[0348] Release agent particle dispersion (1): 30 parts

[0349] Polyaluminium chloride: 0.4 parts

[0350] Ion exchange water: 100 parts

[0351] The above materials were placed in a stainless steel flask, dispersed using an ULTRA-TURRAX manufactured by IKA, and heated to 48° C. in a heating oil bath while stirring. After maintaining at 48° C. for 30 minutes, 70 parts of the polyester resin particle dispersion (1) was added.

[0352] Next, the pH in the system was adjusted to 8.0 using a 0.5 mol / L sodium hydroxide aqueous solution, the stainless steel flask was sealed, the seal of the stirring shaft was magnetically sealed, and the mixture was heated to 90°C while continuing to stir for 3 hours. The mixture was then cooled at a cooling rate of 2°C / min, filtered, and washed with ion exchange water, and then subjected to solid-liquid separation using a Buchner funnel. The solid component was redispersed in ion exchange water at 30°C and washed with stirring at a rotational speed of 300 rpm for 15 minutes. This washing operation was further repeated 6 times, and when the pH of the filtrate was 7.54 and the conductivity was 6.5 μS / cm, solid-liquid separation was performed using filter paper using a Buchner funnel. The solid component was vacuum dried to obtain toner particles (1). The volume average particle size of the toner particles (1) was 5.8 μm.

[0353] <Preparation of Agglomerated Silica Particles A>

[0354] [Preparation of Agglomerated Silica Particles A (1)]

[0355] -Production steps of fumed silica particles-

[0356] Silicon tetrachloride, hydrogen, and oxygen are mixed in a mixing chamber of a burner and burned at a temperature of 1000°C to 3000°C. Silica powder is extracted from the burned gas to obtain agglomerated silica particles (1). The size of the agglomerated particles is adjusted by the burning time.

[0357] -Surface treatment step of agglomerated silica particles-

[0358] 100 parts of agglomerated silica particles (1) and 500 parts of ethanol were placed in an evaporator and stirred for 15 minutes while maintaining the temperature at 40°C. Subsequently, 10 parts of dimethyl silicone oil was added, and the mixture was stirred for 15 minutes. Another 10 parts of dimethyl silicone oil was added, and the mixture was stirred for 15 minutes. The temperature was then raised to 90°C, and the ethanol was dried under reduced pressure. The treated product was removed and vacuum-dried at 120°C for 30 minutes to obtain oil-treated agglomerated silica particles A (1).

[0359] Agglomerated silica particles A(1) have two peaks in the number-based frequency distribution of particle diameters: the first peak is at a particle diameter of 90 nm, and the second peak is at a particle diameter of 65 nm.

[0360] [Preparation of Agglomerated Silica Particles A (2)]

[0361] 250 parts of agglomerated silica particles (1) and 100 parts of hexamethyldisilazane (HMDS) as a hydrophobizing agent were mixed, heated to 130°C for reaction for 2 hours, and then heated to 150°C for drying to obtain agglomerated silica particles A (2) hydrophobized with HMDS.

[0362] [Preparation of Agglomerated Silica Particles A (3)]

[0363] Agglomerated silica particles were prepared in the same manner as in the preparation of agglomerated silica particles (1), treated with dimethyl silicone oil, and then crushed into a desired size by stirring at room temperature to obtain agglomerated silica particles A (3).

[0364] <Preparation of Silica Particles B>

[0365] [Preparation of Silica Particles B (1)]

[0366] -Silica granule granulation step-

[0367] In a glass reaction vessel equipped with a stirrer, a dripper, and a thermometer, 300 parts of methanol and 70 parts of 10% ammonia water were added and mixed to obtain an alkali catalyst solution. After the alkali catalyst solution was adjusted to 30°C, 60 parts of tetramethoxysilane (TMOS) and 1.7 parts of 10% ammonia water were added dropwise while stirring the alkali catalyst solution to obtain a silica particle dispersion. TMOS and 10% ammonia water were added dropwise simultaneously, and the total amount of each was added dropwise over 3 minutes. Subsequently, the silica particle dispersion was concentrated using a rotary filter (R-Fine manufactured by Kotobuki Industry Co., Ltd.) to a solid content concentration of 40% by mass. The concentrated silica particle dispersion was referred to as silica particle dispersion (1).

[0368] -Surface treatment step of silica particles-

[0369] 100 parts of hexamethyldisilazane (HMDS) as a hydrophobizing agent was added to 250 parts of the silica particle dispersion (1), and the mixture was heated to 130°C for reaction for 2 hours, and then heated to 150°C for drying to obtain non-agglomerated silica particles B (1) that had been hydrophobized by HMDS.

[0370] [Preparation of Silica Particles B (2) to (3)]

[0371] The granulation procedure of the silica particles was changed as shown in Table 1, and non-agglomerated silica particles B(2) to (3) were obtained in the same manner as in the preparation of the silica particles B(1).

[0372] [Preparation of Silica Particles B (4)]

[0373] 100 parts of hexamethyldisilazane (HMDS) as a hydrophobizing agent was added to 250 parts of a silica particle dispersion (1), and the mixture was heated to 130°C for reaction for 2 hours, followed by drying at 150°C to obtain hydrophobic silica particles (S1). Subsequently, 0.020% by mass of tetrakis(trimethylsiloxy)silane relative to the silica particle dispersion (1) was prepared, diluted to 5 times the mass with methanol, and added to the hydrophobic silica particles (S1). The mixture was then dried while stirring the reaction system at 80°C to obtain non-agglomerated silica particles B (4).

[0374] [Preparation of Silica Particles B (5) to (6)]

[0375] The amount of low-molecular-weight siloxane added in the surface treatment step of the silica particles was changed as shown in Table 1, and non-agglomerated silica particles B(5) to (6) were obtained in the same manner as in the preparation of silica particles B(4).

[0376] [Preparation of Silica Particles B (7)]

[0377] The silica particle dispersion (1) was dried, and the silica particles were removed. 100 parts of silica particles and 500 parts of ethanol were added to an evaporator and stirred for 15 minutes while maintaining the temperature at 40°C. Then, 10 parts of dimethyl silicone oil was added and stirred for 15 minutes. Another 10 parts of dimethyl silicone oil was added and stirred for 15 minutes. The temperature was then raised to 90°C, and the ethanol was dried under reduced pressure. The treated product was removed and vacuum-dried at 120°C for 30 minutes to obtain oil-treated non-agglomerated silica particles B (7).

[0378] [Table 1]

[0379]

[0380] <Carrier Preparation>

[0381] Ferrite particles (volume average particle size 36 μm): 100 parts

[0382] Toluene: 14 parts

[0383] Styrene-methyl methacrylate copolymer: 2 parts

[0384] (Polymerization mass ratio 90:10, weight average molecular weight 80,000)

[0385] Carbon black (R330 manufactured by Cabot Corporation): 0.2 parts

[0386] Toluene, styrene-methyl methacrylate copolymer, and carbon black were mixed and stirred for 10 minutes using a stirrer to prepare a dispersion. The dispersion and ferrite particles were then added to a vacuum degassing kneader and stirred at 60°C for 30 minutes. The mixture was then degassed under reduced pressure while heating and dried to obtain a carrier.

[0387] <Example 1>

[0388] 100 parts of the toner particles (1) and the amounts of agglomerated silica particles A (1) and silica particles B (1) listed in Table 1 were added to a Henschel mixer and stirred at a peripheral stirring speed of 30 m / sec for 15 minutes to obtain a toner.

[0389] The toner and the carrier were added to a V-type blender at a mixing ratio of toner:carrier=10:100 (mass ratio), and stirred for 20 minutes to obtain a developer.

[0390] <Examples 2 to 10, Comparative Examples 1 to 4>

[0391] A toner and a developer were prepared in the same manner as in Example 1, except that the type or addition amount of the agglomerated silica particles A and / or the type or addition amount of the agglomerated silica particles B were changed as shown in Table 2.

[0392] <Performance Evaluation>

[0393] The toner discharge speed from the cartridge and the amount of toner remaining in the cartridge were evaluated using the following method and criteria.

[0394] A transparent toner cartridge made of polyethylene terephthalate (PET) was filled with 310 g of the toner being evaluated. The cartridge was then placed in an environment with a temperature of 28°C and a relative humidity of 85% for 17 hours. The cartridge was then installed in a replenishing device equipped with a transfer nozzle (a device that replenishes toner from the cartridge to a toner storage container) under an environment with a temperature of 22°C and a relative humidity of 15%. The toner storage container was rotated and the replenishing device operated for 50 minutes. The conditions for rotating the toner storage container and operating the replenishing device were as follows.

[0395] Toner storage container speed: 30rpm

[0396] Length of the delivery nozzle of the supply device: 70mm

[0397] Transmission path inner pitch: 12.5mm

[0398] Conveyor screw outer diameter: 10mm

[0399] Transmission screw shaft diameter: 4mm

[0400] Conveyor screw speed: 62.4rpm

[0401] The average discharge rate (mg / s) from 5 to 15 minutes after the start of the operation and the amount of toner remaining in the toner cartridge after 50 minutes were measured and ranked according to the following criteria.

[0402] [Average discharge speed]

[0403] A: 350mg / s or more

[0404] B: less than 350mg / s, 320mg / s or more

[0405] C: less than 320mg / s, 280mg / s or more

[0406] D: less than 280mg / s

[0407] [Remaining toner amount]

[0408] A: Less than 25g (no problem in actual use)

[0409] B: 25g or more, less than 50g (no problem in actual use)

[0410] C: 50g or more (problems in actual use)

[0411]

Claims

1. A toner for developing electrostatic images, wherein: This toner contains: Toner particles, Oil-treated agglomerated silica particles A, and Silica particles B, which have been subjected to a hydrophobic treatment other than oil removal treatment and may be either agglomerated silica particles or non-agglomerated silica particles, The ratio Da / Db of the average particle size Da of the agglomerated silica particles A to the average particle size Db of the silica particles B is 1.0 or more and 2.0 or less. The toner does not contain an external additive other than the agglomerated silica particles A and the silica particles B, or contains an external additive other than the agglomerated silica particles A and the silica particles B but the average particle diameter of the external additive is smaller than the average particle diameter Da.

2. The electrostatic image developing toner according to claim 1, wherein The mass-based ratio Ma / Mb of the content Ma of the agglomerated silica particles A to the content Mb of the silica particles B is 0.5 or more and 1.0 or less.

3. The electrostatic image developing toner according to claim 1, wherein The silica particles B include non-agglomerated particles of wet-process silica particles.

4. The electrostatic image developing toner according to claim 1, wherein The silica particles B include silica particles subjected to a hydrophobic treatment using 1,1,1,3,3,3-hexamethyldisilazane.

5. The electrostatic image developing toner according to claim 1, wherein The agglomerated silica particles A include agglomerated particles of fumed silica particles. 6 . The electrostatic image developing toner according to claim 1 , wherein the agglomerated silica particles A include agglomerated silica particles treated with silicone oil.

7. The electrostatic image developing toner according to claim 1, wherein There are two peaks in the number-based frequency distribution of the particle size of the agglomerated silica particles A. The first peak is in the range of particle size from 80 nm to 110 nm. The second peak is in the particle size range of 50 nm to 80 nm.

8. The electrostatic image developing toner according to claim 1, wherein The average particle diameter Da is not less than 70 nm and not more than 110 nm.

9. The electrostatic image developing toner according to claim 1, wherein The average particle size Db is not less than 20 nm and not more than 80 nm.

10. The electrostatic image developing toner according to claim 1, wherein The coverage rate of the agglomerated silica particles A on the surfaces of the toner particles is 5% or more and 30% or less.

11. The electrostatic image developing toner according to claim 1, wherein The coverage rate of all external additives on the surfaces of the toner particles is 60% or more and 100% or less.

12. The electrostatic image developing toner according to claim 1, wherein In the number-based frequency distribution of the particle sizes of all external additives, the proportion of particles falling within the range of 20 nm to 100 nm is 75% or more. 13 . The electrostatic image developing toner according to claim 1 , further comprising tetrakis(trimethylsiloxy)silane.

14. The electrostatic image developing toner according to claim 13, wherein The content of tetrakis(trimethylsiloxy)silane is 0.01 ppm or more and 10 ppm or less on a mass basis. 15 . An electrostatic image developer comprising the electrostatic image developing toner according to claim 1 . 16 . A toner cartridge storing the electrostatic image developing toner according to claim 1 , wherein the toner cartridge is attachable to and detachable from an image forming apparatus.

17. The toner cartridge according to claim 16, which is a rotary toner cartridge, wherein The main body storing the electrostatic image developing toner rotates.

18. A process cartridge that is detachably mounted in an image forming apparatus, the process cartridge comprising: a developing mechanism storing an 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; A toner cartridge storing the electrostatic image developing toner according to any one of claims 1 to 14, and The toner supply passage connects the toner cartridge and the developing mechanism, and supplies the electrostatic image developing toner in the toner cartridge to the developing mechanism.

19. An image forming apparatus comprising: Image holding body; a charging mechanism for charging the surface of the image holding member; an electrostatic image forming mechanism for forming an electrostatic image on the surface of the charged image holding member; a developing mechanism storing an 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; a transfer mechanism for transferring the toner image formed on the surface of the image holding member to the surface of the recording medium; a fixing mechanism for fixing the toner image transferred to the surface of the recording medium; a replenishing toner storage portion storing the electrostatic image developing toner according to any one of claims 1 to 14; as well as The toner supply passage connects the replenishing toner storage portion and the developing mechanism, and supplies the electrostatic image developing toner in the replenishing toner storage portion to the developing mechanism.

20. An image forming method comprising the following steps: a charging step of charging the surface of the image holding member; an electrostatic image forming step of forming an electrostatic image on the surface of the charged image holding member; a developing step of developing the electrostatic image formed on the surface of the image holding member into a toner image using an electrostatic image developer; a transfer step of transferring the toner image formed on the surface of the image holding member to the surface of a recording medium; a fixing step of fixing the toner image transferred to the surface of the recording medium; as well as The toner replenishing step replenishes the electrostatic image developing toner in the replenishing toner storage section from the replenishing toner storage section storing the electrostatic image developing toner according to any one of claims 1 to 14 to the developing mechanism through a toner replenishing path connecting the replenishing toner storage section and the developing mechanism.

Images