Toner, toner manufacturing method, toner storage unit, image forming apparatus, and image forming method

Abstract

To provide a toner that is excellent in low temperature fixability and cleaning properties.SOLUTION: A toner has a base particle. An aggregate formed of a plurality of aggregated organic fine particles is attached to the surface of the base particle. The major axis of the aggregate is three times or more the major axis of the organic fine particle. The aggregates occupy the surface of the base particle at a ratio of 10% or more. The aggregates have an average circularity of 0.9 or more.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a toner, a toner manufacturing method, a toner storage unit, an image forming apparatus, and an image forming method. [Background technology]

[0002] In recent years, toners have been required to have smaller particle size and high-temperature offset resistance for improving the quality of output images, low-temperature fixability for energy saving, and heat-resistant storage stability that can withstand high temperatures and humidity during storage and transportation after production. In particular, since the power consumption during fixation accounts for a large portion of the power consumption in the image formation process, improving low-temperature fixability is extremely important.

[0003] In order to improve the low-temperature fixability of a toner, it is necessary to use a material with a low melting point in the toner, but a toner produced using a material with a low melting point is likely to have poor heat-resistant storage stability. Therefore, in order to achieve both low-temperature fixability and heat-resistant storage stability, a method for producing composite resin particles has been proposed in which resin fine particles containing two types of resin as constituent components within the same particle are attached to the surface of resin particles, and then some or all of the resin fine particles are removed (see, for example, Patent Documents 1 to 3).

[0004] Furthermore, conventional toners have a problem in that small-particle external additives (e.g., silica) added to the surface of toner base particles separate from the toner and adhere to the photoreceptor, then aggregate and densify to form strongly adhered silica, resulting in abnormal images due to so-called filming. In response to this problem, toners containing silicone oil-treated silica particles have been proposed in order to prevent image quality defects while maintaining low-temperature fixability (see, for example, Patent Document 4).

[0005] Furthermore, in conventional toners, in order to achieve high heat-resistant storage stability and to suppress toner aggregation over long-term use, a toner has been proposed in which the core layer contains a styrene acrylic modified polyester resin and is coated with spherical particles for the shell covered with a styrene acrylic resin component (see, for example, Patent Document 5). Summary of the Invention [Problem to be solved by the invention]

[0006] However, while conventional toners can achieve both low-temperature fixability and heat-resistant storage stability, there is a problem that as the low-temperature fixability improves, the adhesive force of the toner increases, resulting in poor cleaning performance. Low-temperature fixability is in a trade-off relationship with such cleaning performance, and toners that require improved low-temperature fixability are also required to have improved cleaning performance due to adhesive force.

[0007] An object of the present invention is to provide a toner having excellent low-temperature fixability and cleanability. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, one aspect of the present invention is Toner related to is a toner having base particles, the base particles containing a crystalline polyester resin, and aggregates of a plurality of organic fine particles adhering to the surfaces of the base particles, the organic fine particles have a core resin and a shell resin that coats at least a part of the surface of the core resin, the shell resin containing a styrene-acrylic resin; The long diameter of the aggregates is at least three times the long diameter of the organic microparticles, the proportion of the aggregates on the surface of the base particle is at least 16%, the average circularity of the aggregates is at least 0.9, and the standard deviation of the distance between adjacent organic microparticles on the surface of the base particle is at most 500 nm. [Effects of the Invention]

[0009] According to one aspect of the present invention, a toner having excellent low-temperature fixability and cleanability can be provided. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a schematic diagram illustrating an example of a state of a toner surface. [Figure 2] FIG. 2 is a schematic view illustrating an example of a process cartridge. [Figure 3] FIG. 1 is a schematic diagram illustrating an example of an image forming apparatus. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described.

[0012] <Toner> The toner according to this embodiment has base particles, and aggregates of a plurality of organic fine particles adhere to the surfaces of the base particles.

[0013] [Base particle] In the toner according to this embodiment, the base particles refer to particles that constitute the base of the toner (hereinafter, may be referred to as toner base particles, toner base particles, or toner base). The base particles contain a binder resin, a colorant, and a wax as necessary.

[0014] The binder resin is not particularly limited and can be appropriately selected depending on the purpose. Examples of the binder resin include polyester resin, styrene-acrylic resin, polyol resin, vinyl resin, polyurethane resin, epoxy resin, polyamide resin, polyimide resin, silicon resin, phenol resin, melamine resin, urea resin, aniline resin, ionomer resin, and polycarbonate resin.

[0015] These binder resins may be used alone or in combination of two or more. Among these, polyester resins are preferred because they can impart flexibility to the toner.

[0016] The polyester resin is not particularly limited and can be appropriately selected depending on the purpose. Examples of the polyester resin include amorphous polyester resin, modified polyester resin, crystalline polyester resin, etc. These may be used alone or in combination of two or more.

[0017] Among these, the amorphous polyester resin (hereinafter sometimes referred to as amorphous polyester, non-crystalline polyester, amorphous polyester, amorphous polyester resin, unmodified polyester resin, or polyester resin component A) is not particularly limited and can be appropriately selected depending on the purpose. Examples of amorphous polyester resins include amorphous polyester resins obtained by reacting polyol with polycarboxylic acid.

[0018] In this specification, the amorphous polyester resin refers to a resin obtained by reacting a polyol with a polycarboxylic acid, as described above. Modified polyester resins (for example, prepolymers described below and modified polyester resins obtained by subjecting the prepolymers to a crosslinking and / or elongation reaction) are not included in the amorphous polyester resins described above, but are treated as modified polyester resins.

[0019] The amorphous polyester is a polyester resin component that is soluble in tetrahydrofuran (THF). As the amorphous polyester (polyester resin component A), a linear polyester resin is preferred.

[0020] Examples of polyols include diols.

[0021] Examples of the diol include alkylene (carbon number 2 to 3) oxide (average number of added moles 1 to 10) adducts of bisphenol A such as polyoxypropylene(2.2)-2,2-bis(4-hydroxyphenyl)propane and polyoxyethylene(2.2)-2,2-bis(4-hydroxyphenyl)propane; ethylene glycol, propylene glycol; hydrogenated bisphenol A, and alkylene (carbon number 2 to 3) oxide (average number of added moles 1 to 10) adducts of hydrogenated bisphenol A.

[0022] These diols may be used alone or in combination of two or more. Among these, those containing 40 mol % or more of alkylene glycol are preferred.

[0023] Examples of the polycarboxylic acid include dicarboxylic acids.

[0024] Examples of dicarboxylic acids include alkyl groups having 1 to 20 carbon atoms, such as adipic acid, phthalic acid, isophthalic acid, terephthalic acid, fumaric acid, maleic acid, dodecenylsuccinic acid, and octylsuccinic acid; and succinic acids substituted with alkenyl groups having 2 to 20 carbon atoms. These may be used alone or in combination of two or more. Among these, those containing 50 mol % or more of terephthalic acid are preferred.

[0025] The polyester resin component A (amorphous polyester resin) may contain a trivalent or higher carboxylic acid and / or a trivalent or higher alcohol, a trivalent or higher epoxy compound, or the like at the end of its resin chain in order to adjust the acid value and hydroxyl value.

[0026] Examples of trivalent or higher carboxylic acids include trimellitic acid, pyromellitic acid, and acid anhydrides thereof.

[0027] Examples of trihydric or higher alcohols include glycerin, pentaerythritol, and trimethylolpropane.

[0028] Of these, the polyester resin component A preferably contains a trihydric or higher aliphatic alcohol, from the viewpoint of preventing unevenness and achieving sufficient gloss and image density.

[0029] The molecular weight of the polyester resin component A is not particularly limited and can be appropriately selected depending on the purpose.

[0030] The weight average molecular weight (Mw) of the polyester resin component A is preferably from 3,000 to 10,000, and more preferably from 4,000 to 7,000.

[0031] The number average molecular weight (hereinafter sometimes abbreviated as Mn) of the polyester resin component A is preferably from 1,000 to 4,000, and more preferably from 1,500 to 3,000.

[0032] The molecular weight ratio (Mw / Mn) of the polyester resin component A is preferably from 1.0 to 4.0, more preferably from 1.0 to 3.5.

[0033] Here, the weight average molecular weight and the number average molecular weight can be measured, for example, by gel permeation chromatography (GPC).

[0034] If the weight average molecular weight and number average molecular weight are too low, the toner may have poor heat-resistant storage stability and poor durability against stress such as stirring in a developing machine, whereas if the weight average molecular weight and number average molecular weight are too high, the toner may have high viscoelasticity when melted, resulting in poor low-temperature fixability.

[0035] Furthermore, if the amount of components having a molecular weight of 600 or less is too large, the toner may have poor heat-resistant storage stability and poor durability against stress such as stirring in a developing machine, and if the amount of components having a molecular weight of 600 or less is too small, the toner may have poor low-temperature fixability.

[0036] The THF-soluble component with a molecular weight of 600 or less is preferably 2% by mass to 10% by mass. One method for adjusting the content of this component is to extract polyester resin component A with methanol, remove the component with a molecular weight of 600 or less, and purify the product.

[0037] The acid value of the polyester resin component A is not particularly limited and can be appropriately selected depending on the purpose. The acid value of the polyester resin component A is preferably 1 mgKOH / g to 50 mgKOH / g, and more preferably 5 mgKOH / g to 30 mgKOH / g.

[0038] When the acid value of polyester resin component A is 1 mgKOH / g or more, the toner tends to be negatively charged, and furthermore, the affinity between the toner and paper is improved during fixing to paper, thereby improving low-temperature fixability.On the other hand, when the acid value of polyester resin component A is 50 mgKOH / g or less, the problem of reduced charge stability, particularly charge stability against environmental fluctuations, can be prevented.

[0039] The hydroxyl value of the polyester resin component A is not particularly limited and can be appropriately selected depending on the purpose. The hydroxyl value of the polyester resin component A is preferably 5 mgKOH / g or more.

[0040] The glass transition temperature (hereinafter sometimes abbreviated as Tg) of the polyester resin component A is preferably 40°C to 65°C, more preferably 45°C to 65°C, and even more preferably 50°C to 60°C. When the Tg is 40°C or higher, the toner has improved heat-resistant storage stability and durability against stress such as stirring in a developing machine, and also has improved filming resistance. On the other hand, when the Tg is 65°C or lower, the toner is less susceptible to deformation due to heat and pressure during fixing, and low-temperature fixability is improved.

[0041] The content of the polyester resin component A is preferably 80 parts by mass to 90 parts by mass with respect to 100 parts by mass of the toner.

[0042] The modified polyester resin (hereinafter sometimes referred to as modified polyester or polyester resin component B) is not particularly limited and can be appropriately selected depending on the purpose. Examples of modified polyester resins include a reaction product of an active hydrogen group-containing compound and a polyester resin (hereinafter sometimes referred to as prepolymer or polyester prepolymer) having a site capable of reacting with the active hydrogen group-containing compound.

[0043] Modified polyester is a polyester resin that is insoluble in tetrahydrofuran (THF). The polyester resin component insoluble in tetrahydrofuran (THF) lowers the Tg and melt viscosity, ensuring low-temperature fixability, while having a branched structure in the molecular skeleton, resulting in a three-dimensional network structure of molecular chains, giving it rubber-like properties of deforming at low temperatures but not flowing.

[0044] Since polyester resin component B has an active hydrogen group-containing compound and a site capable of reacting with the active hydrogen group-containing compound, these sites behave like pseudo-crosslinking points, enhancing the rubber-like properties of amorphous polyester resin A. Therefore, by using polyester resin component B, it is possible to produce a toner with excellent heat-resistant storage stability and high-temperature offset resistance.

[0045] The active hydrogen group-containing compound is a compound that reacts with a polyester resin having a site capable of reacting with the active hydrogen group-containing compound.

[0046] The active hydrogen group is not particularly limited and can be appropriately selected depending on the purpose. Examples of the active hydrogen group include a hydroxyl group (alcoholic hydroxyl group and phenolic hydroxyl group), an amino group, a carboxyl group, and a mercapto group. These may be used alone or in combination of two or more.

[0047] The active hydrogen group-containing compound is not particularly limited and can be appropriately selected depending on the purpose. When the polyester resin having a site capable of reacting with the active hydrogen group-containing compound is a polyester resin containing an isocyanate group, the active hydrogen group-containing compound is preferably an amine, since it can increase the molecular weight of the polyester resin by elongation reaction, crosslinking reaction, etc. with the polyester resin.

[0048] The amines are not particularly limited and can be appropriately selected depending on the purpose. Examples of amines include diamines, trivalent or higher amines, amino alcohols, amino mercaptans, amino acids, and compounds in which the amino groups of these are blocked. These may be used alone or in combination of two or more. Among these, diamines and mixtures of diamines with a small amount of trivalent or higher amines are preferred.

[0049] The diamine is not particularly limited and can be appropriately selected depending on the purpose. Examples of the diamine include aromatic diamines, alicyclic diamines, and aliphatic diamines.

[0050] The aromatic diamine is not particularly limited and can be appropriately selected depending on the purpose. Examples of the aromatic diamine include phenylenediamine, diethyltoluenediamine, and 4,4'-diaminodiphenylmethane.

[0051] The alicyclic diamine is not particularly limited and can be appropriately selected depending on the purpose. Examples of the alicyclic diamine include 4,4'-diamino-3,3'-dimethyldicyclohexylmethane, diaminocyclohexane, and isophoronediamine.

[0052] The aliphatic diamine is not particularly limited and can be appropriately selected depending on the purpose. Examples of the aliphatic diamine include ethylenediamine, tetramethylenediamine, and hexamethylenediamine.

[0053] The trivalent or higher amine is not particularly limited and can be appropriately selected depending on the purpose. Examples of the trivalent or higher amine include diethylenetriamine and triethylenetetramine.

[0054] The amino alcohol is not particularly limited and can be appropriately selected depending on the purpose. Examples of the amino alcohol include ethanolamine and hydroxyethylaniline.

[0055] The amino mercaptan is not particularly limited and can be appropriately selected depending on the purpose. Examples of the amino mercaptan include aminoethyl mercaptan and aminopropyl mercaptan.

[0056] The amino acid is not particularly limited and can be appropriately selected depending on the purpose. Examples of the amino acid include aminopropionic acid and aminocaproic acid.

[0057] The compound having a blocked amino group is not particularly limited and can be appropriately selected depending on the purpose. Examples of the compound having a blocked amino group include ketimine compounds and oxazolizone compounds obtained by blocking the amino group with ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone.

[0058] The polyester resin having a site capable of reacting with an active hydrogen group-containing compound is not particularly limited and can be appropriately selected depending on the purpose. Examples of such polyester resins include polyester resins containing isocyanate groups (hereinafter, sometimes referred to as polyester prepolymers having isocyanate groups).

[0059] The polyester resin containing an isocyanate group is not particularly limited and can be appropriately selected depending on the purpose. Examples of the polyester resin containing an isocyanate group include a reaction product of a polyester resin having an active hydrogen group obtained by polycondensation of a polyol and a polycarboxylic acid with a polyisocyanate.

[0060] The polyol is not particularly limited and can be appropriately selected depending on the purpose. Examples of polyols include diols, trihydric or higher alcohols, and mixtures of diols and trihydric or higher alcohols. These may be used alone or in combination of two or more. Among these, diols and mixtures of diols and a small amount of trihydric or higher alcohols are preferred.

[0061] The diol is not particularly limited and can be appropriately selected depending on the purpose. Examples of the diol include linear alkylene glycols, diols having an oxyalkylene group, alicyclic diols, bisphenols, alkylene oxide adducts of alicyclic diols, and alkylene oxide adducts of bisphenols.

[0062] Examples of the chain alkylene glycol include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, and 1,6-hexanediol.

[0063] Examples of diols having an oxyalkylene group include diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

[0064] Examples of the alicyclic diol include 1,4-cyclohexanedimethanol and hydrogenated bisphenol A.

[0065] Examples of bisphenols include bisphenol A, bisphenol F, and bisphenol S.

[0066] Examples of alkylene oxides include ethylene oxide, propylene oxide, and butylene oxide.

[0067] The number of carbon atoms in the chain alkylene glycol is not particularly limited and can be appropriately selected depending on the purpose. The number of carbon atoms in the chain alkylene glycol is preferably 2 to 12.

[0068] Among these, the number of carbon atoms of the chain alkylene glycol is preferably at least one of a chain alkylene glycol having 2 to 12 carbon atoms and an alkylene oxide adduct of a bisphenol. Also, an alkylene oxide adduct of a bisphenol, or a mixture of an alkylene oxide adduct of a bisphenol and a chain alkylene glycol having 2 to 12 carbon atoms is more preferred.

[0069] The trihydric or higher alcohol is not particularly limited and can be appropriately selected depending on the purpose. Examples of the trihydric or higher alcohol include trihydric or higher aliphatic alcohols, trihydric or higher polyphenols, and alkylene oxide adducts of trihydric or higher polyphenols.

[0070] The trihydric or higher aliphatic alcohol is not particularly limited and can be appropriately selected depending on the purpose. Examples of the trihydric or higher aliphatic alcohol include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, and sorbitol.

[0071] The trivalent or higher polyphenols are not particularly limited and can be appropriately selected depending on the purpose. Examples of trivalent or higher polyphenols include trisphenol PA, phenol novolac, and cresol novolac.

[0072] Examples of alkylene oxide adducts of trivalent or higher polyphenols include those obtained by adding alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide to trivalent or higher polyphenols.

[0073] When a diol and a trihydric or higher alcohol are used in combination, the mass ratio of the trihydric or higher alcohol to the diol (trihydric or higher alcohol / diol) is not particularly limited and can be appropriately selected depending on the purpose. In this case, the mass ratio of the trihydric or higher alcohol to the diol is preferably 0.01% by mass to 10% by mass, more preferably 0.01% by mass to 1% by mass.

[0074] The polycarboxylic acid is not particularly limited and can be appropriately selected depending on the purpose. Examples of polycarboxylic acids include dicarboxylic acids, trivalent or higher carboxylic acids, and mixtures of dicarboxylic acids and trivalent or higher carboxylic acids. These may be used alone or in combination of two or more. Among these, dicarboxylic acids and mixtures of dicarboxylic acids and a small amount of trivalent or higher polycarboxylic acids are preferred.

[0075] The dicarboxylic acid is not particularly limited and can be appropriately selected depending on the purpose. Examples of the dicarboxylic acid include divalent alkanoic acids, divalent alkenoic acids, and aromatic dicarboxylic acids.

[0076] The divalent alkanoic acid is not particularly limited and can be appropriately selected depending on the purpose. Examples of the divalent alkanoic acid include succinic acid, adipic acid, and sebacic acid.

[0077] The divalent alkenoic acid is not particularly limited and can be appropriately selected depending on the purpose, but is preferably a divalent alkenoic acid having 4 to 20 carbon atoms. The divalent alkenoic acid having 4 to 20 carbon atoms is not particularly limited and can be appropriately selected depending on the purpose. Examples of divalent alkenoic acids having 4 to 20 carbon atoms include maleic acid and fumaric acid.

[0078] The aromatic dicarboxylic acid is not particularly limited and can be appropriately selected depending on the purpose, but aromatic dicarboxylic acids having 8 to 20 carbon atoms are preferred. The aromatic dicarboxylic acid having 8 to 20 carbon atoms is not particularly limited and can be appropriately selected depending on the purpose. Examples of aromatic dicarboxylic acids having 8 to 20 carbon atoms include phthalic acid, isophthalic acid, terephthalic acid, and naphthalenedicarboxylic acid.

[0079] The trivalent or higher carboxylic acid is not particularly limited and can be appropriately selected depending on the purpose. Examples of the trivalent or higher carboxylic acid include trivalent or higher aromatic carboxylic acids.

[0080] The trivalent or higher aromatic carboxylic acid is not particularly limited and can be appropriately selected depending on the purpose, but a trivalent or higher aromatic carboxylic acid having 9 to 20 carbon atoms is preferred. The trivalent or higher aromatic carboxylic acid having 9 to 20 carbon atoms is not particularly limited and can be appropriately selected depending on the purpose. Examples of the trivalent or higher aromatic carboxylic acid having 9 to 20 carbon atoms include trimellitic acid and pyromellitic acid.

[0081] As the polycarboxylic acid, an acid anhydride or a lower alkyl ester of any of dicarboxylic acids, tricarboxylic or higher carboxylic acids, and a mixture of a dicarboxylic acid and a tricarboxylic or higher carboxylic acid can also be used.

[0082] The lower alkyl ester is not particularly limited and can be appropriately selected depending on the purpose. Examples of the lower alkyl ester include methyl ester, ethyl ester, and isopropyl ester.

[0083] When a mixture of a dicarboxylic acid and a tricarboxylic or higher carboxylic acid is used, the mass ratio of the tricarboxylic or higher carboxylic acid to the dicarboxylic acid (tricarboxylic or higher carboxylic acid / dicarboxylic acid) is not particularly limited and can be appropriately selected depending on the purpose. In this case, the mass ratio of the tricarboxylic or higher carboxylic acid to the dicarboxylic acid is preferably 0.01% by mass to 10% by mass, more preferably 0.01% by mass to 1% by mass.

[0084] When polyol and polycarboxylic acid are polycondensed, the equivalent ratio of the hydroxyl groups of the polyol to the carboxyl groups of the polycarboxylic acid (hydroxyl groups of the polyol / carboxyl groups of the polycarboxylic acid) is not particularly limited and can be appropriately selected depending on the purpose. In this case, the equivalent ratio of the hydroxyl groups of the polyol to the carboxyl groups of the polycarboxylic acid is preferably 1 to 2, more preferably 1 to 1.5, and even more preferably 1.02 to 1.3.

[0085] The content of the polyol-derived structural unit in the polyester prepolymer having an isocyanate group is not particularly limited and can be appropriately selected depending on the purpose, and in this case, the content is preferably 0.5% by mass to 40% by mass, more preferably 1% by mass to 30% by mass, and even more preferably 2% by mass to 20% by mass.

[0086] In this case, if the content is less than 0.5% by mass, the hot offset resistance may decrease, making it difficult to achieve both heat-resistant storage stability and low-temperature fixability of the toner, and if the content exceeds 40% by mass, the low-temperature fixability may decrease.

[0087] The polyisocyanate is not particularly limited and can be appropriately selected depending on the purpose. Examples of the polyisocyanate include aliphatic diisocyanates, alicyclic diisocyanates, aromatic diisocyanates, araliphatic diisocyanates, isocyanurates, and those obtained by blocking these with phenol derivatives, oximes, caprolactam, etc.

[0088] The aliphatic diisocyanate is not particularly limited and can be appropriately selected depending on the purpose. Examples of the aliphatic diisocyanate include tetramethylene diisocyanate, hexamethylene diisocyanate, methyl 2,6-diisocyanatocaproate, octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, tetradecamethylene diisocyanate, trimethylhexane diisocyanate, and tetramethylhexane diisocyanate.

[0089] The alicyclic diisocyanate is not particularly limited and can be appropriately selected depending on the purpose. Examples of the alicyclic diisocyanate include isophorone diisocyanate and cyclohexylmethane diisocyanate.

[0090] The aromatic diisocyanate is not particularly limited and can be appropriately selected depending on the purpose. Examples of the aromatic diisocyanate include tolylene diisocyanate, diisocyanatodiphenylmethane, 1,5-naphthylene diisocyanate, 4,4'-diisocyanatodiphenyl, 4,4'-diisocyanato-3,3'-dimethyldiphenyl, 4,4'-diisocyanato-3-methyldiphenylmethane, and 4,4'-diisocyanato-diphenyl ether.

[0091] The araliphatic diisocyanate is not particularly limited and can be appropriately selected depending on the purpose. Examples of the araliphatic diisocyanate include α,α,α',α'-tetramethylxylylene diisocyanate.

[0092] The isocyanurates are not particularly limited and can be appropriately selected depending on the purpose. Examples of the isocyanurates include tris(isocyanatoalkyl)isocyanurate and tris(isocyanatocycloalkyl)isocyanurate. These may be used alone or in combination of two or more.

[0093] When polyisocyanate is reacted with a polyester resin having a hydroxyl group, the equivalent ratio (NCO / OH) of the isocyanate group of the polyisocyanate to the hydroxyl group of the polyester resin is not particularly limited and can be appropriately selected depending on the purpose.

[0094] In this case, the equivalent ratio of the isocyanate groups of the polyisocyanate to the hydroxyl groups of the polyester resin is preferably 1 to 5, more preferably 1.2 to 4, and even more preferably 1.5 to 2.5. If the equivalent ratio is less than 1, the hot offset resistance may decrease, and if it exceeds 5, the low-temperature fixability may decrease.

[0095] The content of the polyisocyanate-derived structural unit in the polyester prepolymer having an isocyanate group is not particularly limited and can be appropriately selected depending on the purpose.

[0096] The content of the polyisocyanate-derived structural unit in the polyester prepolymer having an isocyanate group is preferably 0.5% by mass to 40% by mass, more preferably 1% by mass to 30% by mass, and even more preferably 2% by mass to 20% by mass. If the content is less than 0.5% by mass, hot offset resistance may decrease, and if it exceeds 40% by mass, low-temperature fixability may decrease.

[0097] The average number of isocyanate groups per molecule of the polyester prepolymer having isocyanate groups is not particularly limited and can be appropriately selected depending on the purpose. In this case, the average number is preferably 1 or more, more preferably 1.5 to 3, and even more preferably 1.8 to 2.5. If the average number is less than 1, the molecular weight of the modified polyester resin will be low, and hot offset resistance may be reduced.

[0098] The modified polyester resin can be produced by a one-shot method, etc. As an example, a method for producing a urea-modified polyester resin will be described.

[0099] First, a polyol and a polycarboxylic acid are heated to 150°C to 280°C in the presence of a catalyst such as tetrabutoxy titanate or dibutyltin oxide, and the water produced is removed, if necessary, under reduced pressure, to obtain a polyester resin having hydroxyl groups.

[0100] Next, a polyester resin having a hydroxyl group is reacted with a polyisocyanate at 40°C to 140°C to obtain a polyester prepolymer having an isocyanate group.Furthermore, a polyester prepolymer having an isocyanate group is reacted with an amine at 0°C to 140°C to obtain a urea-modified polyester resin.

[0101] The number average molecular weight (Mn) of the modified polyester resin is not particularly limited and can be appropriately selected depending on the purpose. The number average molecular weight (Mn) of the modified polyester resin, as measured by GPC (gel permeation chromatography), is preferably 1,000 to 10,000, more preferably 1,500 to 6,000.

[0102] The weight-average molecular weight of the modified polyester resin is not particularly limited and can be appropriately selected depending on the purpose, but the weight-average molecular weight of the modified polyester resin is preferably 20,000 or more and 1,000,000 or less as measured by GPC (gel permeation chromatography).

[0103] If the weight average molecular weight is 20,000 or more, the toner tends to flow easily at low temperatures, which can prevent the problems of poor heat-resistant storage stability and low viscosity when melted, which can prevent the problems of poor high-temperature offset properties.

[0104] When a polyester resin having a hydroxyl group is reacted with a polyisocyanate, or when a polyester prepolymer having an isocyanate group is reacted with an amine, a solvent may be used as needed.

[0105] The solvent is not particularly limited and can be appropriately selected depending on the purpose. Examples of the solvent include those that are inactive to isocyanate groups, such as aromatic solvents, ketones, esters, amides, and ethers.

[0106] Examples of aromatic solvents include toluene and xylene. Examples of ketones include acetone, methyl ethyl ketone, and methyl isobutyl ketone. Examples of esters include ethyl acetate. Examples of amides include dimethylformamide and dimethylacetamide. Examples of ethers include tetrahydrofuran.

[0107] The glass transition temperature of the modified polyester resin is preferably -60°C or higher and 0°C or lower, and more preferably -40°C or higher and -20°C or lower.

[0108] If the glass transition temperature is -60°C or higher, the toner cannot be prevented from flowing at low temperatures, which can prevent problems such as deterioration of heat-resistant storage stability and filming resistance.If the glass transition temperature is 0°C or lower, the toner cannot be sufficiently deformed by heat and pressure during fixing, which can prevent problems such as insufficient low-temperature fixing ability.

[0109] The content of the modified polyester is not particularly limited and can be appropriately selected depending on the purpose. The content of the modified polyester is preferably 1 to 15 parts by mass, more preferably 5 to 10 parts by mass, per 100 parts by mass of the toner.

[0110] The molecular structures of polyester resin components A and B can be confirmed by nuclear magnetic resonance (NMR) measurements using a solution or solid, as well as by X-ray diffraction (XRD), gas chromatography-mass spectrometry (GC / MS), liquid chromatography-mass spectrometry (LC / MS), infrared spectroscopy (IR), and other measurements.

[0111] Conveniently, in the infrared absorption spectrum, 965±10 cm -1 and 990±10cm -1 One method is to detect amorphous polyester resins that do not have absorption due to olefin δCH (out-of-plane bending vibration).

[0112] The above-mentioned crystalline polyester resin (hereinafter sometimes referred to as crystalline polyester or polyester resin component C) is not particularly limited and can be appropriately selected depending on the purpose. Examples of the crystalline polyester resin include crystalline polyester resins obtained by reacting polyol with polycarboxylic acid.

[0113] Because crystalline polyester resins have high crystallinity, they exhibit heat melting properties that cause a rapid drop in viscosity near the fixing start temperature. By using crystalline polyester resins with such properties together with amorphous polyester resins, the heat resistance is good due to the crystallinity up to just before the melting start temperature, but at the melting start temperature, the crystalline polyester resin melts, causing a rapid drop in viscosity (sharp melt).

[0114] As a result, the toner is compatible with the amorphous polyester resin, and the viscosity of both resins drops sharply, resulting in a toner with excellent heat-resistant storage stability and low-temperature fixability. The toner also exhibits excellent release width (the difference between the minimum fixation temperature and the temperature at which high-temperature offset occurs).

[0115] In this specification, the term "crystalline polyester resin" refers to a resin obtained by reacting a polyol with a polycarboxylic acid, as described above. Modified polyester resins, such as prepolymers and resins obtained by crosslinking and / or elongating the prepolymers, are not included in the crystalline polyester resin category.

[0116] The polyol is not particularly limited and can be appropriately selected depending on the purpose. Examples of the polyol include diols and trihydric or higher alcohols.

[0117] Examples of diols include saturated aliphatic diols. Examples of saturated aliphatic diols include linear saturated aliphatic diols and branched saturated aliphatic diols. These may be used alone or in combination of two or more. Among these, linear saturated aliphatic diols are preferred, and linear saturated aliphatic diols having 2 to 12 carbon atoms are more preferred, as they can improve crystallinity and prevent a decrease in melting point.

[0118] Examples of saturated aliphatic diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, and 1,14-eicosanediol.

[0119] Among these, the saturated aliphatic diols are preferably ethylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, and 1,12-dodecanediol, because they provide a crystalline polyester resin with high crystallinity and excellent sharp melt properties.

[0120] Examples of trihydric or higher alcohols include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol.

[0121] The polycarboxylic acid is not particularly limited and can be appropriately selected depending on the purpose. Examples of the polycarboxylic acid include dicarboxylic acids and tricarboxylic or higher carboxylic acids.

[0122] Examples of dicarboxylic acids include saturated aliphatic dicarboxylic acids such as 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, and 1,18-octadecanedicarboxylic acid; aromatic dicarboxylic acids such as dibasic acids such as phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid, malonic acid, and mesaconic acid; and anhydrides thereof or lower (C1 to C3) alkyl esters thereof.

[0123] Examples of trivalent or higher carboxylic acids include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, and anhydrides or lower (C1 to C3) alkyl esters of these.

[0124] The polycarboxylic acid may contain a dicarboxylic acid having a sulfonic acid group in addition to a saturated aliphatic dicarboxylic acid or an aromatic dicarboxylic acid. Furthermore, a dicarboxylic acid having a double bond in addition to a saturated aliphatic dicarboxylic acid or an aromatic dicarboxylic acid may be contained. These may be used alone or in combination of two or more.

[0125] The crystalline polyester resin is preferably composed of a linear saturated aliphatic dicarboxylic acid having 4 to 12 carbon atoms and a linear saturated aliphatic diol having 2 to 12 carbon atoms.

[0126] That is, the crystalline polyester resin preferably has a constituent unit derived from a saturated aliphatic dicarboxylic acid having from 4 to 12 carbon atoms and a constituent unit derived from a saturated aliphatic diol having from 2 to 12 carbon atoms. This is preferable in that the resin has high crystallinity and excellent sharp melting properties, and can therefore exhibit excellent low-temperature fixability.

[0127] The presence or absence of crystallinity of the crystalline polyester resin (polyester resin component C) in this embodiment can be confirmed by a crystal analysis X-ray diffractometer (X'Pert Pro MRD, manufactured by Philips). The measurement method will be described below.

[0128] First, the target sample is ground in a mortar to prepare a sample powder, which is then evenly applied to a sample holder. The sample holder is then placed in the diffractometer, measurements are performed, and a diffraction spectrum is obtained. A sample is considered to be crystalline if the peak half-width of the peak with the greatest intensity among the peaks obtained in the range of 20°<2θ<25° is 2.0 or less.

[0129] In this embodiment, a polyester resin that does not exhibit the above-described state is referred to as an amorphous polyester resin, in contrast to a crystalline polyester resin.

[0130] The conditions for measuring the X-ray diffraction are as follows. Tension kV: 45kV Current: 40mA MPSS Upper Gonio Scan mode: continuous Start angle: 3° End angle: 35° Angle Step: 0.02° Lucident beam optics ·Divergence slit: Div slit 1 / 2 Diffraction beam optics ·Anti scatter slit: As fixed 1 / 2 ·Receiving slit: Prog rec slit

[0131] The melting point of the crystalline polyester resin is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 60° C. or higher and 80° C. or lower. If the melting point is 60° C. or higher, the crystalline polyester resin is likely to melt at low temperatures, preventing the problem of a decrease in the heat-resistant storage stability of the toner, while if the melting point is 80° C. or lower, the problem of a decrease in low-temperature fixability due to insufficient melting of the crystalline polyester resin due to heating during fixing can be prevented.

[0132] The molecular weight of the crystalline polyester resin is not particularly limited and can be appropriately selected depending on the purpose.

[0133] The orthodichlorobenzene soluble portion of the crystalline polyester resin preferably has a weight average molecular weight (Mw) of 3,000 to 30,000, more preferably 5,000 to 15,000, as measured by GPC.

[0134] The orthodichlorobenzene soluble portion of the crystalline polyester resin preferably has a number average molecular weight (Mn) of 1,000 to 10,000, more preferably 2,000 to 10,000, as measured by GPC.

[0135] The molecular weight ratio (Mw / Mn) of the crystalline polyester resin is preferably 1.0 to 10, more preferably 1.0 to 5.0, because a resin having a sharp molecular weight distribution and a low molecular weight has excellent low-temperature fixability, and the presence of a large amount of low-molecular-weight components reduces heat-resistant storage stability.

[0136] The acid value of the crystalline polyester resin is not particularly limited and can be appropriately selected depending on the purpose. From the viewpoint of the affinity between paper and resin, in order to achieve the desired low-temperature fixability, the acid value of the crystalline polyester resin is preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g or more. On the other hand, in order to improve the high-temperature offset resistance, the acid value is preferably 45 mgKOH / g or less.

[0137] The hydroxyl value of the crystalline polyester resin is not particularly limited and can be appropriately selected depending on the purpose. In order to achieve the desired low-temperature fixability and good charging characteristics, the hydroxyl value of the crystalline polyester resin is preferably 0 mgKOH / g to 50 mgKOH / g, more preferably 5 mgKOH / g to 50 mgKOH / g.

[0138] The molecular structure of crystalline polyester resin can be confirmed by NMR measurement in solution or solid, as well as by X-ray diffraction, GC / MS, LC / MS, IR, etc. In the infrared absorption spectrum, the -1 or 990±10cm -1 One example is a method for detecting a crystalline polyester resin that has absorption based on the δCH (out-of-plane bending vibration) of olefin.

[0139] The content of the crystalline polyester resin (polyester resin component C) is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 3 to 20 parts by mass, more preferably 5 to 15 parts by mass, per 100 parts by mass of the toner.

[0140] When the content of the crystalline polyester resin is 3 parts by mass or more, the problem of poor low-temperature fixability due to insufficient sharp melting by the crystalline polyester resin can be prevented, and when the content of the crystalline polyester resin is 20 parts by mass or less, the problem of reduced heat-resistant storage stability and increased image fogging can be prevented.

[0141] The colorant contained in the base particles is not particularly limited and can be appropriately selected depending on the purpose.

[0142] Examples of colorants include carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, yellow ochre, yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR), permanent yellow (NCG), Balkan fast yellow (5G, R), tartrazine lake, quinoline yellow lake, anthrazan yellow BGL, isoindolinone yellow, red iron oxide, red lead, vermilion, cadmium Red, Cadmium Mercury Red, Antimony Vermilion, Permanent Red 4R, Para Red, Faise Red, Parachlor Orthonitroaniline Red, Lithol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Lithol Rubin GX, Permanent Red F5R, Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Tor Ijin Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thioindigo Red B, Thioindigo Maroon, Oil Red, Quinacridone Red, Pyrazolone Red, Polyazo Red, Chrome Vermilion, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkali Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal-free Phthalo Cyanine blue, phthalocyanine blue, fast sky blue, indanthrene blue (RS, BC), indigo, ultramarine, Prussian blue, anthraquinone blue, fast violet B, methyl violet lake, cobalt purple, manganese purple, dioxane violet, anthraquinone violet, chrome green, zinc green, chromium oxide, pyridian, emerald green, pigment green B, naphthol green B, green gold, acid green lake, malachite green lake, phthalocyanine green, anthraquinone green,Examples include titanium oxide, zinc oxide, and lithopone.

[0143] The content of the colorant is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 1 to 15 parts by mass, more preferably 3 to 10 parts by mass, per 100 parts by mass of the toner.

[0144] The colorant can also be used as a masterbatch in which it is combined with a resin.

[0145] Examples of resins to be used in the production of a masterbatch or to be kneaded with a masterbatch include, in addition to polyester resins, polymers of styrene or its substitution products such as polystyrene, poly-p-chlorostyrene, and polyvinyltoluene; styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, and styrene-α-chloromethyl methacrylate copolymer. Examples of suitable styrene copolymers include polymers, styrene-acrylonitrile copolymers, styrene-vinyl methyl ketone copolymers, styrene-butadiene copolymers, styrene-isoprene copolymers, styrene-acrylonitrile-indene copolymers, styrene-maleic acid copolymers, and styrene-maleic acid ester copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, epoxy resins, epoxy polyol resins, polyurethanes, polyamides, polyvinyl butyral, polyacrylic acid resins, rosin, modified rosin, terpene resins, aliphatic or alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffin, and paraffin wax.

[0146] These resins may be used alone or in combination of two or more.

[0147] The masterbatch can be obtained by mixing and kneading a resin for the masterbatch and a colorant under high shear force, and an organic solvent can be used to enhance the interaction between the colorant and the resin.

[0148] Alternatively, a masterbatch may be produced using a method known as the flushing method, in which an aqueous paste containing a colorant and water is mixed and kneaded with a resin and an organic solvent, the colorant is transferred to the resin, and the water and organic solvent components are removed. This method is preferred because it does not require drying, since the wet cake of the colorant can be used as is. A high-shear dispersing device such as a three-roll mill is preferably used for mixing and kneading.

[0149] The wax contained in the base particles can function as a release agent in the toner. The wax is not particularly limited and can be appropriately selected depending on the purpose. Examples of waxes include natural waxes and synthetic waxes. These may be used alone or in combination of two or more.

[0150] Examples of natural waxes include plant waxes such as carnauba wax, cotton wax, and rice wax; animal waxes such as beeswax and lanolin; mineral waxes such as ozokerite and cerusin; and petroleum waxes such as paraffin, microcrystalline, and petrolatum.

[0151] Examples of synthetic waxes include synthetic hydrocarbon waxes such as Fischer-Tropsch wax, polyethylene, and polypropylene; fatty acid amide compounds such as esters, ketones, ethers, 12-hydroxystearic acid amide, stearic acid amide, phthalimide anhydride, and chlorinated hydrocarbons; low-molecular-weight crystalline polymer resins such as polyacrylate homopolymers and copolymers (e.g., n-stearyl acrylate-ethyl methacrylate copolymers) such as poly-n-stearyl methacrylate and poly-n-lauryl methacrylate; and crystalline polymers with long alkyl groups in the side chains.

[0152] Among these, preferred waxes are hydrocarbon waxes such as paraffin wax, microcrystalline wax, Fischer-Tropsch wax, polyethylene wax, and polypropylene wax.

[0153] The melting point of the release agent is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 60°C or higher and 80°C or lower. If the melting point is 60°C or higher, the release agent tends to melt at low temperatures, preventing the problem of poor heat-resistant storage stability. If the melting point is 80°C or lower, even when the resin melts and is in the fixing temperature range, the release agent does not melt sufficiently, causing fixing offset and preventing the problem of image defects.

[0154] The content of the release agent is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 2 to 10 parts by mass, and more preferably 3 to 8 parts by mass, relative to 100 parts by mass of toner. When the content of the release agent is 2 parts by mass or more, problems such as poor high-temperature offset resistance during fixing and poor low-temperature fixing ability can be prevented, and when it is 10 parts by mass or less, problems such as a decrease in heat-resistant storage stability and a tendency for image fogging to occur can be prevented.

[0155] The base particles are not particularly limited as long as they are those used in ordinary toner base particles, and may contain other components appropriately selected depending on the purpose. The content of other components is not particularly limited as long as they do not impair the properties of the toner, and can be appropriately selected depending on the purpose.

[0156] The other components are not particularly limited as long as they are those used in ordinary toners, and can be appropriately selected depending on the purpose. Examples of the other components include a charge control agent, an external additive, a flowability improver, a cleaning property improver, and a magnetic material.

[0157] The charge control agent is not particularly limited and can be appropriately selected depending on the purpose.

[0158] Examples of charge control agents include nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxyamines, quaternary ammonium salts (including fluorine-modified quaternary ammonium salts), alkylamides, phosphorus simple substance or compounds, tungsten simple substance or compounds, fluorine-based activators, metal salicylate salts, and metal salts of salicylic acid derivatives.

[0159] Commercially available charge control agents include, for example, the nigrosine dye BONTRON (registered trademark) 03, the quaternary ammonium salt BONTRON P-51, the metal-containing azo dye BONTRON S-34, the oxynaphthoic acid metal complex BONTRON E-82, the salicylic acid metal complex BONTRON E-84, and the phenolic condensate BONTRON E-89 (all manufactured by Orient Chemical Industry Co., Ltd.), the quaternary ammonium salt molybdenum complexes TP-302 and TP-415 (all manufactured by Hodogaya Chemical Co., Ltd.), and LRA-901, and the boron complex LR-147 (all manufactured by Nippon Carlit Co., Ltd.).

[0160] The content of the charge control agent is determined by the type of binder resin, the presence or absence of additives used as needed, and the toner production method including the dispersion method, and is not uniquely limited. The content of the charge control agent is preferably 0.1 to 10 parts by mass, more preferably 0.2 to 5 parts by mass, relative to 100 parts by mass of the binder resin.

[0161] If the content of the charge control agent exceeds 10 parts by mass, the chargeability of the toner becomes too high, which reduces the effect of the main charge control agent and increases the electrostatic attraction force with the developing roller, which may result in a decrease in the fluidity of the developer and a decrease in image density.

[0162] These charge control agents can be melt-kneaded together with the master batch and the resin and then dissolved and dispersed, or they can be added when directly dissolved or dispersed in an organic solvent, or they can be fixed on the toner surface after toner particles are produced.

[0163] The external additive is not particularly limited and can be appropriately selected depending on the purpose.

[0164] Examples of external additives include silica fine particles, hydrophobic silica, fatty acid metal salts (e.g., zinc stearate, aluminum stearate, etc.), metal oxides (e.g., titania, alumina, tin oxide, antimony oxide, etc.), and fluoropolymers. These may be used alone or in combination of two or more. Suitable external additives include hydrophobized silica, titania, titanium oxide, and alumina fine particles.

[0165] Examples of silica fine particles include R972, R974, RX200, RY200, R202, R805, and R812 (all manufactured by Nippon Aerosil Co., Ltd.).

[0166] Examples of titania microparticles include P-25 (manufactured by Nippon Aerosil Co., Ltd.), STT-30, STT-65C-S (all manufactured by Titanium Industries Co., Ltd.), TAF-140 (manufactured by Fuji Titanium Industries Co., Ltd.), MT-150W, MT-500B, MT-600B, MT-150A (all manufactured by Teika Corporation).

[0167] Examples of hydrophobized titanium oxide microparticles include T-805 (manufactured by Nippon Aerosil Co., Ltd.), STT-30A, STT-65S-S (all manufactured by Titanium Industries Co., Ltd.), TAF-500T, TAF-1500T (all manufactured by Fuji Titanium Industries Co., Ltd.), MT-100S, MT-100T (all manufactured by Teika Corporation), and IT-S (manufactured by Ishihara Sangyo Kaisha).

[0168] Hydrophobized oxide microparticles, hydrophobized silica microparticles, hydrophobized titania microparticles, and hydrophobized alumina microparticles can be obtained, for example, by treating hydrophilic microparticles with a silane coupling agent such as methyltrimethoxysilane, methyltriethoxysilane, or octyltrimethoxysilane.

[0169] Silicone oil-treated oxide fine particles and inorganic fine particles, which are prepared by treating silicone oil with heat as necessary to form inorganic fine particles, are also suitable.

[0170] Examples of silicone oils include dimethyl silicone oil, methylphenyl silicone oil, chlorophenyl silicone oil, methylhydrogen silicone oil, alkyl-modified silicone oil, fluorine-modified silicone oil, polyether-modified silicone oil, alcohol-modified silicone oil, amino-modified silicone oil, epoxy-modified silicone oil, epoxy-polyether-modified silicone oil, phenol-modified silicone oil, carboxyl-modified silicone oil, mercapto-modified silicone oil, methacrylic-modified silicone oil, and α-methylstyrene-modified silicone oil.

[0171] The average particle size of the primary particles of the external additive is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 100 nm or less, more preferably 1 nm to 100 nm, even more preferably 3 nm to 70 nm, and particularly preferably 5 nm to 70 nm. When the average particle size of the primary particles is within this range, it is possible to prevent the inorganic fine particles from being buried in the toner, making it difficult for them to effectively perform their functions, and the photoreceptor surface from being unevenly damaged.

[0172] The external additive preferably contains at least one type of inorganic fine particles that have been hydrophobized and have an average primary particle size of 20 nm or less, and at least one type of inorganic fine particles that have an average primary particle size of 30 nm or more.

[0173] The specific surface area of the external additive by the BET method is 20m 2 / g~500m 2 / g is preferred.

[0174] The content of the external additive is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.1 to 5 parts by mass, more preferably 0.3 to 3 parts by mass, relative to 100 parts by mass of the toner.

[0175] The flowability improver is not particularly limited as long as it is capable of performing a surface treatment to increase hydrophobicity and prevent deterioration of flowability and charging properties even under high humidity conditions, and can be appropriately selected depending on the purpose.

[0176] Examples of the flow improver include silane coupling agents, silylating agents, silane coupling agents having a fluorinated alkyl group, organic titanate coupling agents, aluminum coupling agents, silicone oils, and modified silicone oils.

[0177] The above-mentioned silica and titanium oxide are preferably surface-treated with such a flowability improver and used as hydrophobic silica and hydrophobic titanium oxide.

[0178] The cleaning property improver is not particularly limited as long as it is added to the toner to remove the developer remaining on the photosensitive member or primary transfer medium after transfer, and can be appropriately selected depending on the purpose.

[0179] Examples of cleaning improvers include fatty acid metal salts such as zinc stearate, calcium stearate, and stearic acid, and polymer microparticles produced by soap-free emulsion polymerization such as polymethyl methacrylate microparticles and polystyrene microparticles. Polymer microparticles with a relatively narrow particle size distribution are preferred, and those with a volume average particle size of 0.01 μm to 1 μm are suitable.

[0180] The magnetic material is not particularly limited and can be appropriately selected depending on the purpose. Examples of magnetic materials include iron powder, magnetite, ferrite, etc. Among these, white materials are preferred in terms of color tone.

[0181] The glass transition temperature (Tg1st) of the toner in the first temperature rise in differential scanning calorimetry (DSC) is preferably 40° C. to 65° C. The glass transition temperature (Tg1st) of the toner component insoluble in tetrahydrofuran (THF) in the first temperature rise in DSC is preferably −45° C. to 5° C.

[0182] The glass transition temperature (Tg2nd) of the THF-soluble component of the toner in the second heating run in DSC is preferably 20° C. to 65° C. It is preferable that the glass transition temperature (Tg1st) in the first heating run in differential scanning calorimetry (DSC) and the glass transition temperature (Tg2nd) in the second heating run satisfy Tg1st-Tg2nd≧10° C., since this improves the low-temperature fixability and heat-resistant storage stability.

[0183] Here, the glass transition temperature of the toner can be measured using, for example, a differential scanning calorimeter (DSC-60, manufactured by Shimadzu Corporation).

[0184] For example, a DSC curve is measured using the above-mentioned differential scanning calorimeter. From the obtained DSC curve, an analysis program is used to select the DSC curve during the first heating run, and the glass transition temperature Tg1st during the first heating run can be determined using the endothermic shoulder temperature in the analysis program. A DSC curve during the second heating run can be selected, and the glass transition temperature Tg2nd during the second heating run can be determined using the endothermic shoulder temperature.

[0185] [aggregate] In the toner according to the present embodiment, the aggregate (hereinafter sometimes referred to as an aggregate of organic fine particles) is formed by aggregating a plurality of organic fine particles. In this specification, "aggregation" does not refer to a state in which primary particles are gathered together while maintaining their shape, but rather to a state in which particles are gathered together and some of their shapes are no longer maintained.

[0186] The method for aggregating the organic fine particles is not particularly limited, but for example, there is a method of changing the solubility parameter (SP value).

[0187] The solubility parameter (hereinafter sometimes abbreviated as SP value) is an index showing affinity, and two components with similar SP values have high affinity (easy to mix), while two components with different SP values have low affinity (difficult to mix). In this embodiment, if the SP value is increased, the aggregation of organic fine particles will progress, but if it is too high, the organic fine particles will tend to dissolve in the solvent.

[0188] Aggregates of organic fine particles adhere to the surface of the base particle. Here, FIG. 1 is a schematic diagram showing an example of the state of the toner surface. The surface of the toner base 1 is not flat but slightly rounded (curved). Resin fine particles 2 adhere to the surface of the toner base 1. A portion of the resin fine particles 2 adhering to the surface of the toner base 1 forms aggregates 2'.

[0189] The major axis of the aggregate is three times or more the major axis of the organic fine particles. In other words, when the major axis of the smallest particle of organic fine particles 2 is R, the major axis R' of aggregate 2' is 3R or more. The major axis R of the smallest particle of resin fine particles and the major axis R' of the aggregate are measured on images taken with a scanning electron microscope (SEM).

[0190] The major axis of the smallest particle of the organic fine particles is not particularly limited, but is preferably 10 nm or more and 35 nm or less, more preferably 15 nm or more and 53 nm or less, and even more preferably 20 nm or more and 25 nm or less. Here, the volume average particle diameter can be measured, for example, by observing images using a scanning electron microscope (SEM).

[0191] In the toner of this embodiment, the proportion of the aggregates on the surface of the base particle is 10% or more, preferably 15% or more, more preferably 50% or more, and even more preferably 60% or more. Hereinafter, the proportion of the aggregates on the surface of the base particle may be referred to as the occupancy rate. There is no particular upper limit to the occupancy rate, and theoretically, a maximum of 100% is allowed, but in practice, it is 80% or less.

[0192] The occupancy rate of the aggregates is determined as follows after removing as much of the external additives as possible by ultrasonic liberation treatment to bring the particles into a state close to the toner base particles.

[0193] (1) To separate the external additives, 50 ml of a 5% by weight aqueous solution containing a surfactant (Noigen ET-165, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was added to a 100 ml screw tube, and 3 g of toner was added to the mixture, which was then gently moved up and down and side to side. The mixture was then stirred in a ball mill for 30 minutes to allow the toner to blend into the dispersion solution. (2) Then, an ultrasonic homogenizer (manufactured by SONICS & MATERIALS, homogenizer, model VCX750, CV33) is used, and ultrasonic energy is applied for 60 minutes at an output of 40 W.

[0194] The ultrasonic conditions are as follows: Vibration time: 60 minutes continuous ·Amplitude: 40W ·Vibration start temperature: 23±1.5℃ ·Temperature during vibration: 23±1.5℃

[0195] (3) The dispersion obtained in (1) and (2) above is suction filtered using filter paper (Advantec Toyo Co., Ltd., qualitative filter paper No. 2, 110 mm), washed twice with ion-exchanged water, filtered again, and the free additives are removed, after which the toner particles are dried. (4) The toner obtained in (3) above is observed with a scanning electron microscope (SEM). First, the external additives and fillers containing Si are detected by observing the backscattered electron image. (5) The image from (4) above is binarized using image processing software (ImageJ) to remove external additives and fillers.

[0196] Next, a secondary electron image is observed at the same position as in (4) above. Since resin fine particles (organic fine particles) cannot be observed in a backscattered electron image but can only be observed in a secondary electron image, the image obtained in (4) above is compared, and the fine particles present in the areas other than the remaining external additives and filler (areas other than those excluded in (4) above) are considered to be resin fine particles, and image processing software is used to measure the total area occupied by each aggregate, the area of the toner matrix, and the distance between the resin fine particles (the distance connecting the centers of the particles).

[0197] The total area occupied by each aggregate and the area of the toner base particle are calculated by calculating the circumference of the aggregate and the toner base particle using image processing software (ImageJ), and the area of the circle with the same circumference as the calculated circumference is taken as the area of the aggregate and the base particle, respectively. The aggregate occupancy is calculated using the following formula (1):

[0198]

number

[0199] This measurement is carried out for 100 binarized images (one toner particle per image), and the average values are taken as the average values of the aggregate occupancy rate and the distance between resin particles.

[0200] In the toner of this embodiment, the average circularity of the aggregates is 0.9 or more, preferably 0.92 or more, and more preferably 0.94 or more. The upper limit of the average circularity is not particularly limited, and theoretically, a maximum of 1 is allowed, but in practice, it is 0.98 or less.

[0201] The average circularity of the aggregates can be measured, for example, by observing images using a scanning electron microscope (SEM).

[0202] In the toner of this embodiment, the standard deviation of the distance between adjacent organic fine particles on the surface of the base particle is preferably 500 nm or less. Here, the distance between adjacent organic fine particles (hereinafter referred to as the distance between organic fine particles) is the distance L connecting the center C1 of organic fine particle 21 and the center C2 of organic fine particle 22, as shown in FIG.

[0203] The centers of the organic fine particles are shown as the center points of an image of the organic fine particles observed with a scanning electron microscope (SEM). Note that, because the surface of the toner matrix is curved, the distance between organic fine particles is not the measured distance between organic fine particles on the surface of the toner matrix, but the shortest distance between organic fine particles on the image of the organic fine particles on the surface of the toner matrix photographed with a scanning electron microscope (SEM).

[0204] The standard deviation of the distance between organic fine particles is calculated by the following formula (2) where the distance between particles is x.

number

[0205] The shooting conditions are as follows. Scanning electron microscope: SU-8230 (Hitachi High-Technologies Corporation) Magnification: 35,000x Image capture: SE (L): Secondary electrons, BSE (backscattered electrons) Acceleration voltage: 2.0 kV ·Acceleration current: 1.0μA Probe current: Normal Focus mode: UHR WD:8.0mm

[0206] In the toner of this embodiment, the volume average particle size of the aggregates is preferably 70 nm or more and 200 nm or less, more preferably 100 nm or more and 200 nm or less, and even more preferably 140 nm or more and 200 nm or less. Here, the volume average particle size can be measured, for example, by observing images using a scanning electron microscope (SEM).

[0207] [Organic fine particles] In the toner of this embodiment, the organic fine particles (hereinafter sometimes referred to as resin fine particles or resin fine particles D) that constitute the aggregates preferably have a core resin (core portion) and a shell resin (outer shell portion) that covers at least a portion of the surface of the core resin, more preferably are composed of the core resin and the shell resin, and even more preferably contain a vinyl-based unit composed of the core resin and the shell resin.

[0208] In this embodiment, as shown in Fig. 1, the organic fine particles 2 are composed of a core resin 3 and a shell resin 4. The particle size M of the organic fine particles 2 indicates the volume average primary particle size of the resin fine particles 2. Here, the volume average primary particle size indicates the average value of primary particle diameters (average primary particle diameter on a number basis) determined from a transmission electron microscope photograph (TEM image) or a scanning electron microscope photograph (SEM image) of the particles.

[0209] The vinyl-based unit constituting the organic fine particles is preferably, for example, a polymer obtained by homopolymerizing or copolymerizing a vinyl monomer.

[0210] Examples of the vinyl monomer include the following (1) to (10).

[0211] (1) Vinyl hydrocarbons Examples of vinyl hydrocarbons include (1-1) aliphatic vinyl hydrocarbons, (1-2) alicyclic vinyl hydrocarbons, and (1-3) aromatic vinyl hydrocarbons.

[0212] (1-1) Aliphatic vinyl hydrocarbons Examples of aliphatic vinyl hydrocarbons include alkenes and alkadienes. Specific examples of alkenes include ethylene, propylene, and α-olefins. Specific examples of alkadienes include butadiene, isoprene, 1,4-pentadiene, 1,6-hexadiene, and 1,7-octadiene.

[0213] (1-2) Alicyclic vinyl hydrocarbons Alicyclic vinyl hydrocarbons include mono- or di-cycloalkenes and alkadienes, and specific examples include dicyclopentadiene and terpene.

[0214] (1-3) Aromatic vinyl hydrocarbons Examples of aromatic vinyl hydrocarbons include styrene and its hydrocarbyl (alkyl, cycloalkyl, aralkyl and / or alkenyl) substituted derivatives, and specific examples include α-methylstyrene, 2,4-dimethylstyrene and vinylnaphthalene.

[0215] (2) Carboxyl group-containing vinyl monomers and their salts Examples of carboxyl group-containing vinyl monomers and salts thereof include unsaturated monocarboxylic acids (salts) having 3 to 30 carbon atoms, unsaturated dicarboxylic acids (salts), and anhydrides (salts) thereof, and monoalkyl (carbon number 1 to 24) esters thereof or salts thereof.

[0216] Specific examples include carboxyl group-containing vinyl monomers such as (meth)acrylic acid, maleic anhydride, maleic acid monoalkyl esters, fumaric acid, fumaric acid monoalkyl esters, crotonic acid, itaconic acid, itaconic acid monoalkyl esters, itaconic acid glycol monoether, citraconic acid, citraconic acid monoalkyl esters, and cinnamic acid, and metal salts thereof.

[0217] In this specification, the term "(salt)" refers to an acid or a salt thereof. For example, an unsaturated monocarboxylic acid (salt) having 3 to 30 carbon atoms refers to an unsaturated monocarboxylic acid or a salt thereof.

[0218] In this specification, "(meth)acrylic" means methacrylic acid or acrylic acid.

[0219] (3) Sulfonic acid group-containing vinyl monomers, vinyl sulfate monoesters, and their salts Examples of sulfone group-containing vinyl monomers, vinyl sulfate monoesters, and salts thereof include alkenesulfonic acids (salts) having 2 to 14 carbon atoms, alkylsulfonic acids (salts) having 2 to 24 carbon atoms, sulfo(hydroxy)alkyl-(meth)acrylates (salts), (meth)acrylamides (salts), and alkylallylsulfosuccinic acids (salts).

[0220] Specifically, an example of an alkene sulfonic acid having 2 to 14 carbon atoms is vinyl sulfonic acid (salt). An example of an alkyl sulfonic acid (salt) having 2 to 24 carbon atoms is α-methylstyrene sulfonic acid (salt). An example of a sulfo(hydroxy)alkyl-(meth)acrylate (salt) or (meth)acrylamide (salt) is sulfopropyl (meth)acrylate (salt), sulfuric acid ester (salt), or sulfonic acid group-containing vinyl monomer (salt).

[0221] (4) Phosphate-containing vinyl monomers and their salts Examples of the phosphoric acid group-containing vinyl monomer and its salt include (meth)acryloyloxyalkyl (C1 to C24) phosphoric acid monoester (salt), (meth)acryloyloxyalkyl (C1 to C24) phosphonic acid (salt), and the like.

[0222] Specific examples of (meth)acryloyloxyalkyl (C1 to C24) phosphate monoesters (salts) include 2-hydroxyethyl (meth)acryloylphosphate (salts), phenyl-2-acryloyloxyethyl phosphate (salts), etc. Specific examples of (meth)acryloyloxyalkyl (C1 to C24) phosphonic acids (salts) include 2-acryloyloxyethyl phosphonic acid (salts).

[0223] In this specification, "(meth)acryloyl" means methacryloyl or acryloyl.

[0224] Examples of the salts of (2) to (4) above include alkali metal salts (sodium salts, potassium salts, etc.), alkaline earth metal salts (calcium salts, magnesium salts, etc.), ammonium salts, amine salts, and quaternary ammonium salts.

[0225] (5) Hydroxyl group-containing vinyl monomer Examples of hydroxyl group-containing vinyl monomers include hydroxystyrene, N-methylol(meth)acrylamide, hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate, polyethylene glycol mono(meth)acrylate, (meth)allyl alcohol, crotyl alcohol, isocrotyl alcohol, 1-buten-3-ol, 2-buten-1-ol, 2-butene-1,4-diol, propargyl alcohol, 2-hydroxyethylpropenyl ether, and sucrose allyl ether.

[0226] In this specification, "(meth)acrylate" means methacrylate or acrylate.

[0227] (6) Nitrogen-containing vinyl monomers Examples of nitrogen-containing vinyl monomers include (6-1) amino group-containing vinyl monomers, (6-2) amide group-containing vinyl monomers, (6-3) nitrile group-containing vinyl monomers, (6-4) quaternary ammonium cation group-containing vinyl monomers, and (6-5) nitro group-containing vinyl monomers.

[0228] (6-1) Amino group-containing vinyl monomer Examples of amino group-containing vinyl monomers include aminoethyl (meth)acrylate.

[0229] (6-2) Amide group-containing vinyl monomer Examples of the amide group-containing vinyl monomer include (meth)acrylamide and N-methyl(meth)acrylamide.

[0230] (6-3) Nitrile group-containing vinyl monomer Examples of the nitrile group-containing vinyl monomer include (meth)acrylonitrile, cyanostyrene, and cyanoacrylate.

[0231] (6-4) Vinyl Monomers Containing Quaternary Ammonium Cation Groups Examples of the quaternary ammonium cation group-containing vinyl monomer include quaternized products of tertiary amine group-containing vinyl monomers such as dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylamide, diethylaminoethyl (meth)acrylamide, and diallylamine (which have been quaternized using a quaternizing agent such as methyl chloride, dimethyl sulfate, benzyl chloride, or dimethyl carbonate).

[0232] (6-5) Nitro group-containing vinyl monomer An example of the nitro group-containing vinyl monomer is nitrostyrene.

[0233] (7) Epoxy group-containing vinyl monomer Examples of epoxy group-containing vinyl monomers include glycidyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, and p-vinylphenyl phenyl oxide.

[0234] (8) Halogen-containing vinyl monomers Examples of halogen-containing vinyl monomers include vinyl chloride, vinyl bromide, vinylidene chloride, allyl chloride, chlorostyrene, bromostyrene, dichlorostyrene, chloromethylstyrene, tetrafluorostyrene, and chloroprene.

[0235] (9) Vinyl esters, vinyl (thio)ethers, vinyl ketones Examples of vinyl esters include vinyl acetate, vinyl butyrate, vinyl propionate, vinyl butyrate, diallyl phthalate, diallyl adipate, isopropenyl acetate, vinyl methacrylate, methyl 4-vinyl benzoate, cyclohexyl methacrylate, benzyl methacrylate, phenyl (meth)acrylate, vinyl methoxyacetate, vinyl benzoate, ethyl α-ethoxyacrylate, alkyl (meth)acrylates having an alkyl group of 1 to 50 carbon atoms [methyl (meth) acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, dodecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, eicosyl (meth)acrylate, behenyl (meth)acrylate, etc.)], dialkyl fumarate (wherein the two alkyl groups are linear, branched, or alicyclic groups having 2 to 8 carbon atoms), dialkyl maleate esters (the two alkyl groups are straight-chain, branched-chain, or alicyclic groups having 2 to 8 carbon atoms), poly(meth)allyloxyalkanes [diallyloxyethane, triallyloxyethane, tetraallyloxyethane, tetraallyloxypropane, tetraallyloxybutane, tetramethallyloxyethane, etc.], vinyl monomers having polyalkylene glycol chains [polyethylene glycol (molecular weight 300) mono(meth)acrylate, polypropylene glycol (molecular weight 500) monoacrylate, methyl alcohol ethylene oxide 10 mole adduct (meth)acrylate, lauryl alcohol ethylene oxide 30 mole adduct (meth)acrylate, etc.], poly(meth)acrylates [poly(meth)acrylates of polyhydric alcohols: ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, polyethylene glycol di(meth)acrylate, etc.], and the like.

[0236] Examples of vinyl (thio)ethers include vinyl methyl ether.

[0237] Examples of vinyl ketones include vinyl methyl ketone.

[0238] (10) Other vinyl monomers Other vinyl monomers include, for example, tetrafluoroethylene, fluoroacrylate, isocyanatoethyl (meth)acrylate, and m-isopropenyl-α,α-dimethylbenzyl isocyanate.

[0239] In synthesizing the core resin 3 constituting the organic fine particles 2, the vinyl monomers (1) to (10) above may be used alone or in combination of two or more.

[0240] As the core resin, from the viewpoint of low-temperature fixability, a styrene-(meth)acrylic acid ester copolymer and a (meth)acrylic acid ester copolymer are preferred, and a styrene-(meth)acrylic acid ester copolymer is more preferred.

[0241] Examples of vinyl monomers used for the shell resin include those similar to those used for the core resin. For synthesizing the shell resin, the vinyl monomers (1) to (10) listed above for the core resin may be used alone or in combination of two or more.

[0242] As the shell resin, from the viewpoint of low-temperature fixability, a styrene-(meth)acrylic acid ester copolymer and a (meth)acrylic acid ester copolymer are preferred, and a styrene-(meth)acrylic acid ester copolymer is more preferred.

[0243] The shell resin having a carboxylic acid imparts an acid value to the resin, and makes it easier to form toner particles in which the organic fine particles (resin fine particles D) adhere to the surface of the toner particles.

[0244] The core resin preferably has a loss modulus G" of viscoelastic properties at 100° C. and a frequency of 1 Hz of 0.01 MPa to 1.0 MPa, more preferably 0.02 MPa to 0.5 MPa, and even more preferably 0.05 MPa to 0.3 MPa.

[0245] The shell resin preferably has a loss modulus G" of viscoelastic properties at 100° C. and a frequency of 1 Hz of 1.5 MPa to 100 MPa, more preferably 1.7 MPa to 30 MPa, and even more preferably 2.0 MPa to 10 MPa.

[0246] If the viscoelastic loss modulus G" is within this range, it is easy to form toner particles in which organic fine particles (resin fine particles D) containing a core resin and a shell resin as constituent components within the same particle adhere to the surface of the toner particle.

[0247] The loss modulus G" of the viscoelastic properties of the core resin and shell resin at a frequency of 1 Hz and 100°C can be adjusted by changing the types and composition ratios of the constituent monomers or by adjusting the polymerization conditions (types and amounts of initiator and chain transfer agent, reaction temperature, etc.). Specifically, for example, by using the following composition, it is possible to adjust the loss modulus G" of each resin to fall within the above-mentioned range.

[0248] (1) The glass transition temperature (Tg1) calculated from the constituent monomers of the core resin is preferably −30° C. to 100° C., more preferably 0° C. to 80° C., and even more preferably 30° C. to 60° C. The glass transition temperature (Tg2) calculated from the constituent monomers of the shell resin is preferably 0° C. to 150° C., and more preferably 50° C. to 100° C.

[0249] The glass transition temperature (Tg) calculated from the constituent monomers is a value that can be calculated by the Fox method. Here, the Fox method [TGFox, Phys. Rev., 86, 652 (1952)] is a method for estimating the Tg of a copolymer from the Tg of each homopolymer, as shown in the following formula:

[0250] 1 / Tg=W1 / Tg1+W2 / Tg2++Wn / Tgn [In the formula, Tg is the glass transition temperature (expressed in absolute temperature) of the copolymer, Tg1, Tg2...Tgn are the glass transition temperatures (expressed in absolute temperature) of the homopolymers of each monomer component, and W1, W2...Wn are the weight fractions of each monomer component.]

[0251] (2) The calculated acid value (AV1) of the core resin is preferably 0 mgKOH / g to 50 mgKOH / g, more preferably 0 mgKOH / g to 20 mgKOH / g, and even more preferably 0 mgKOH / g. The calculated acid value (AV2) of the shell resin is preferably 75 mgKOH / g to 400 mgKOH / g, and more preferably 150 mgKOH / g to 300 mgKOH / g.

[0252] The calculated acid value is a theoretical acid value calculated from the molar amount of acidic groups contained in the constituent monomers and the total weight of the constituent monomers.

[0253] As a constituent monomer that satisfies the conditions (1) and (2), for the core resin, for example, there can be mentioned a resin that contains styrene as a constituent monomer in an amount of preferably 10% by mass to 100% by mass, more preferably 30% by mass to 90% by mass, based on the total mass of the core resin, and methacrylic acid and / or acrylic acid in an amount of preferably 0% by mass to 7.5% by mass, more preferably 0% by mass to 2.5% by mass, based on the total mass of the core resin.

[0254] Furthermore, the shell resin may, for example, contain, as constituent monomers, preferably 10% by mass to 80% by mass, more preferably 30% by mass to 60% by mass of styrene, and preferably a total of 10% by mass to 60% by mass, more preferably a total of 30% by mass to 50% by mass of methacrylic acid and / or acrylic acid, based on the total mass of the shell resin.

[0255] (3) Adjust the polymerization conditions (type and amount of initiator and chain transfer agent, reaction temperature, etc.). Specifically, the number average molecular weight (Mn1) of the core resin is preferably 1,000 to 1,000,000, more preferably 10,000 to 100,000. The number average molecular weight (Mn2) of the shell resin is preferably 2,000 to 2,000,000, more preferably 20,000 to 200,000.

[0256] The loss modulus G" of the viscoelastic properties in this embodiment is measured, for example, using the following viscoelasticity measuring device. Equipment: ARES-24A (Rheometrics) Jig: 25mm parallel plate Frequency: 1Hz Distortion rate: 10% Heating rate: 5℃ / min

[0257] From the viewpoint of low-temperature fixability, the acid value (AVd1) of the core resin is preferably from 0 mgKOH / g to 50 mgKOH / g, more preferably from 0 mgKOH / g to 20 mgKOH / g, and even more preferably 0 mgKOH / g.

[0258] The acid value can be measured, for example, by the method of JIS K0070:1992.

[0259] A core resin having an acid value within this range is a resin that contains methacrylic acid and / or acrylic acid in a total amount of preferably 0 to 7.5% by mass, more preferably 0 to 2.5% by mass, based on the total mass of the core resin.

[0260] The acid value (AVd2) of the shell resin is preferably 75 mgKOH / g to 400 mgKOH / g, and more preferably 150 mgKOH / g to 300 mgKOH / g.

[0261] If the acid value of the shell resin is within this range, organic fine particles (resin fine particles D) containing a vinyl unit in which the core resin and shell resin are contained as constituent components in the same particle are likely to form particles adhered to the surface of the toner.

[0262] A shell resin having an acid value within this range is a resin that contains methacrylic acid and / or acrylic acid in a total amount of preferably 10% to 60% by mass, and more preferably 30% to 50% by mass, based on the total mass of the shell resin.

[0263] The glass transition temperature of the shell resin is preferably higher than the glass transition temperature of the core resin, more preferably at least 10° C. higher, and even more preferably at least 20° C. Within this range, an excellent balance is achieved between the ease of forming toner particles in which organic fine particles (resin fine particles D) adhere to the toner surface and the low-temperature fixability of the toner particles of this embodiment.

[0264] The glass transition temperature (Tg) of the core resin is preferably −30° C. to 100° C., more preferably 0° C. to 80° C., and even more preferably 30° C. to 60° C. If the glass transition temperature of the core resin is −30° C. or higher, the heat-resistant storage stability can be improved, and if it is 100° C. or lower, there is little inhibition of low-temperature fixability.

[0265] The glass transition temperature of the shell resin is preferably 0° C. to 150° C., and more preferably 50° C. to 100° C. If the glass transition temperature of the shell resin is 0° C. or higher, the heat-resistant storage stability can be improved, and if it is 150° C. or lower, there is little inhibition of low-temperature fixability.

[0266] In this embodiment, Tg is measured by a differential scanning calorimeter (manufactured by Seiko Instruments Inc., DSC20, SSC / 580) according to the method (DSC) specified in ASTM D3418-82.

[0267] The SP value of the core resin is set to 8.5 (cal / cm) from the viewpoint of ease of forming toner particles. 3 ) 1 / 2 ~12.5(cal / cm 3 ) 1 / 2 is preferable, and 9 (cal / cm 3 ) 1 / 2 ~12(cal / cm 3 ) 1 / 2 More preferably, 10 (cal / cm3 ) 1 / 2 ~11(cal / cm 3 ) 1 / 2 is more preferable. The SP value of the core resin can be adjusted by changing the types and composition ratio of the constituent monomers.

[0268] From the viewpoint of ease of forming toner particles, the SP value of the shell resin is set to 9 (cal / cm 3 ) 1 / 2 ~13(cal / cm 3 ) 1 / 2 is preferable, and 9.5 (cal / cm 3 ) 1 / 2 ~12.5(cal / cm 3 ) 1 / 2 More preferably, 10.5 (cal / cm 3 ) 1 / 2 ~11.5(cal / cm 3 ) 1 / 2 is more preferable. The SP value of the shell resin can be adjusted by changing the types and composition ratio of the constituent monomers.

[0269] The SP value in this embodiment is calculated by the method by Fedors [Polym. Eng. Sci. 14(2)152, (1974)].

[0270] From the viewpoint of the Tg of the core resin and copolymerizability with other vinyl monomers, the core resin preferably contains 10% by mass to 100% by mass, and more preferably 30% by mass to 90% by mass of styrene as a constituent monomer based on the total mass of the core resin.

[0271] From the viewpoint of the Tg of the shell resin and copolymerizability with other monomers, the shell resin preferably contains 10% by mass to 80% by mass, and more preferably 30% by mass to 60% by mass, of styrene as a constituent monomer based on the total mass of the shell resin.

[0272] The number average molecular weight (Mn) of the core resin is preferably 1,000 to 1,000,000, and more preferably 10,000 to 100,000. When Mn is 1,000 or more, the heat-resistant storage stability of the toner is improved, and when Mn is 1,000,000 or less, the low-temperature fixability of the toner is less hindered.

[0273] The weight average molecular weight (Mw) of the core resin is preferably 10,000 to 10,000,000, and more preferably 100,000 to 1,000,000. When Mw is 10,000 or more, the heat-resistant storage stability of the toner is improved, and when it is 10,000,000 or less, the low-temperature fixability of the toner is less hindered.

[0274] The number average molecular weight (Mn) of the shell resin is preferably 2,000 to 2,000,000, and more preferably 20,000 to 200,000. If the number average molecular weight is 2,000 or more, the heat-resistant storage stability is improved, and if it is 2,000,000 or less, the low-temperature fixability of the toner is less hindered.

[0275] The weight-average molecular weight (Mw) of the shell resin is preferably larger than that of the core resin, more preferably 1.5 times or more larger than that of the core resin, and even more preferably 2.0 times or more larger than that of the core resin. Within this range, an excellent balance between ease of toner particle formation and low-temperature fixability is achieved.

[0276] The weight average molecular weight (Mw) of the shell resin is preferably 20,000 to 20,000,000, and more preferably 200,000 to 2,000,000. If the weight average molecular weight is 20,000 or more, the heat-resistant storage stability is improved, and if it is 20,000,000 or less, there is little inhibition of low-temperature fixability.

[0277] Among these, it is preferable that the Mw of the core resin is 100,000 to 500,000, the Mw of the shell resin is 200,000 to 2,000,000, and the "Mw of the core resin" is less than the "Mw of the shell resin."

[0278] In the present embodiment, Mn and Mw can be measured using gel permeation chromatography (GPC) under the following conditions.

[0279] Equipment (example): HLC-8120 (Tosoh Corporation) Column (example): 2 TSK GEL GMH6 (Tosoh Corporation) ·Measurement temperature: 40℃ Sample solution: 0.25% by weight tetrahydrofuran solution (insoluble matter filtered off with a glass filter) ·Solution injection volume: 100μL Detector: Refractive index detector Reference material: 12 standard polystyrenes (TSK standard POLYSTYRENE) (molecular weights: 500, 1,050, 2,800, 5,970, 9,100, 18,100, 37,900, 96,400, 190,000, 355,000, 1,090,000, 2,890,000) [manufactured by Tosoh Corporation]

[0280] The mass ratio of the core resin to the shell resin in the organic fine particles (resin fine particles D) is preferably 5 / 95 to 95 / 5, more preferably 25 / 75 to 75 / 25, and even more preferably 40 / 60 to 60 / 40.

[0281] When the mass ratio of the core resin to the shell resin is 5 / 95 or more, toner particles in which the resin particles D adhere to the surfaces of the toner resin particles are easily formed. Also, when the mass ratio of the core resin to the shell resin is 95 / 5 or less, a toner with excellent heat-resistant storage stability is obtained.

[0282] Although the organic fine particles (resin fine particles D) can be used alone, the toner of this embodiment can also be obtained by using organic fine particles E made of two types of styrene-acrylic resin (resins e1 and e2) in combination with organic fine particles F made of one type of styrene-acrylic resin. For example, the toner of this embodiment is obtained by forming the organic fine particles from a styrene-acrylic resin and by forming the shell resin of the organic fine particles containing a styrene-acrylic resin.

[0283] The organic fine particles E and F mixed in advance during emulsification adhere uniformly to the toner surface, and the organic fine particles F adhered to the toner surface and all or part of the resin e1 in the organic fine particles E are removed in the washing step described below, allowing the organic fine particles E to adhere uniformly with gaps between them.

[0284] Methods for producing organic fine particles (resin fine particles D) include known production methods, such as the following production methods (I) to (V).

[0285] (I) A method of seed polymerization of constituent monomers of a resin (hereinafter referred to as resin (d2)) constituting a shell resin using fine particles of a resin (hereinafter referred to as resin (d1)) constituting a core resin in an aqueous dispersion as seeds. (II) A method of seed polymerization of constituent monomers of resin (d1) using fine particles of resin (d2) in an aqueous dispersion as seeds. (III) A method in which a mixture of the resin (d1) and the resin (d2) is emulsified in an aqueous medium to obtain an aqueous dispersion of resin fine particles. (IV) A method in which a mixture of the resin (d1) and the constituent monomers of the resin (d2) is emulsified in an aqueous medium, and then the constituent monomers of the resin (d1) are polymerized to obtain an aqueous dispersion of resin fine particles. (V) A method in which a mixture of resin (d1) and constituent monomers of resin (d2) is emulsified in an aqueous medium, and then the constituent monomers of resin (d2) are polymerized to obtain an aqueous dispersion of resin fine particles.

[0286] The fact that resin microparticle D contains core resin (d1) and shell resin (d2) as constituent components within the same particle can be confirmed by observing elemental mapping images of a cross section of resin microparticle (B) and by observing electron microscope images.

[0287] In observing the element mapping image, for example, a known surface elemental analyzer (such as TOF-SIMSEDX-SEM) is used. In observing the electron microscope observation image, for example, the cut surface of the resin microparticle (B) is stained with a staining agent corresponding to the functional groups contained in the resin (d1) and the resin (d2).

[0288] The resin microparticles obtained by this method may be obtained as a mixture containing resin microparticles D containing resin (d1) and resin (d2) as constituent components in the same particle, as well as resin microparticles containing only resin (d1) as a constituent resin component and resin microparticles containing only resin (d2) as a constituent resin component. In the composite step described below, such a mixture may be used as is, or only resin microparticles D may be isolated and used.

[0289] Specific examples of (I) include a method in which constituent monomers of resin (d1) are polymerized dropwise to produce an aqueous dispersion of resin microparticles containing resin (d1), and then this is used as a seed to perform seed polymerization of constituent monomers of resin (d2); and a method in which resin (d1) previously produced by solution polymerization or the like is emulsified and dispersed in water, and then this is used as a seed to perform seed polymerization of constituent monomers of resin (d2).

[0290] Specific examples of (II) include a method in which the constituent monomers of resin (d2) are polymerized dropwise to produce an aqueous dispersion of resin microparticles containing resin (d2), and then this is used as a seed to perform seed polymerization of the constituent monomers of resin (d1); and a method in which resin (d2) previously produced by solution polymerization or the like is emulsified and dispersed in water, and then this is used as a seed to perform seed polymerization of the constituent monomers of resin (d1).

[0291] A specific example of (III) is a method in which a solution or melt of resin (d1) and resin (d2) previously produced by solution polymerization or the like is mixed, and then the mixture is emulsified and dispersed in an aqueous medium.

[0292] Specific examples of (IV) include a method in which resin (d1) produced in advance by solution polymerization or the like is mixed with constituent monomers (of resin d2), the mixture is emulsified and dispersed in an aqueous medium, and then the constituent monomers of resin (d1) are polymerized; and a method in which resin (d2) is produced from the constituent monomers of resin (d1), the mixture is emulsified and dispersed in an aqueous medium, and then the constituent monomers of resin (d1) are polymerized.

[0293] Specific examples of (V) include a method in which resin (d1), which has been produced in advance by solution polymerization or the like, is mixed with constituent monomers of resin (d2), the mixture is emulsified and dispersed in an aqueous medium, and then the constituent monomers of (d2) are polymerized; and a method in which resin (d1) is produced in the constituent monomers of resin (d2), the mixture is emulsified and dispersed in an aqueous medium, and then the constituent monomers of resin (d2) are polymerized.

[0294] In this embodiment, any of the above production methods (I) to (V) can be suitably used.

[0295] The resin fine particles (B) are preferably used as an aqueous dispersion.

[0296] The material used in the aqueous dispersion (hereinafter referred to as aqueous medium) is not particularly limited as long as it dissolves in water, and can be appropriately selected depending on the purpose. Examples of aqueous media include surfactant G, buffering agents, protective colloids, etc. These may be used alone or in combination of two or more.

[0297] The aqueous medium used in the aqueous dispersion is not particularly limited as long as it is a liquid that essentially contains water, and examples thereof include aqueous solutions containing water.

[0298] Examples of surfactants G include nonionic surfactants G1, anionic surfactants G2, cationic surfactants G3, amphoteric surfactants G4, and other emulsifying dispersants G5.

[0299] Examples of the nonionic surfactant G1 (hereinafter abbreviated as G1) include AO (alkylene oxide) addition type nonionic surfactants and polyhydric alcohol type nonionic surfactants.

[0300] Examples of AO-addition type nonionic surfactants include EO adducts of aliphatic alcohols having 10 to 20 carbon atoms, EO adducts of phenols, EO (ethylene oxide) adducts of nonylphenols, EO adducts of alkylamines having 8 to 22 carbon atoms, and EO adducts of poly(oxypropylene) glycols.

[0301] Examples of polyhydric alcohol-type nonionic surfactants include fatty acid (8 to 24 carbon atoms) esters of polyhydric (tri- to octahydric or higher) alcohols (2 to 30 carbon atoms) (e.g., glycerin monostearate, glycerin monooleate, sorbitan monolaurate, sorbitan monooleate, etc.), and alkyl (4 to 24 carbon atoms) poly(degree of polymerization 1 to 10) glycosides.

[0302] Examples of the anionic surfactant G2 (hereinafter simply referred to as G2) include ethercarboxylic acids having a hydrocarbon group of 8 to 24 carbon atoms or salts thereof, sulfate esters or ether sulfate esters having a hydrocarbon group of 8 to 24 carbon atoms and salts thereof, sulfonates having a hydrocarbon group of 8 to 24 carbon atoms, sulfosuccinates having one or two hydrocarbon groups of 8 to 24 carbon atoms, phosphate esters or ether phosphate esters having a hydrocarbon group of 8 to 24 carbon atoms and salts thereof, fatty acid salts having a hydrocarbon group of 8 to 24 carbon atoms, and acylated amino acid salts having a hydrocarbon group of 8 to 24 carbon atoms.

[0303] Examples of ethercarboxylic acids or salts thereof having a hydrocarbon group with 8 to 24 carbon atoms include sodium lauryl ether acetate and (poly)oxyethylene (number of moles added: 1 to 100) sodium lauryl ether acetate.

[0304] Examples of sulfates or ether sulfates having a hydrocarbon group having 8 to 24 carbon atoms and salts thereof include sodium lauryl sulfate, (poly)oxyethylene (number of moles added: 1 to 100) sodium lauryl sulfate, (poly)oxyethylene (number of moles added: 1 to 100) triethanolamine lauryl sulfate, and (poly)oxyethylene (number of moles added: 1 to 100) sodium coconut oil fatty acid monoethanolamide sulfate.

[0305] Examples of sulfonates having a hydrocarbon group with 8 to 24 carbon atoms include sodium dodecylbenzenesulfonate.

[0306] Examples of the phosphate ester or ether phosphate ester having a hydrocarbon group with 8 to 24 carbon atoms and salts thereof include sodium lauryl phosphate and sodium (poly)oxyethylene (addition mole number 1 to 100) lauryl ether phosphate.

[0307] Examples of fatty acid salts having a hydrocarbon group with 8 to 24 carbon atoms include sodium laurate and triethanolamine laurate.

[0308] Examples of acylated amino acid salts having a hydrocarbon group having 8 to 24 carbon atoms include sodium coconut oil fatty acid methyl taurate, sodium coconut oil fatty acid sarcosine, triethanolamine coconut oil fatty acid sarcosine, triethanolamine N-coconut oil fatty acid acyl-L-glutamate, sodium N-coconut oil fatty acid acyl-L-glutamate, and sodium lauroylmethyl-β-alanine.

[0309] Examples of cationic surfactant G3 (hereinafter abbreviated as G3) include quaternary ammonium salt types and amine salt types.

[0310] Examples of the quaternary ammonium salt type include stearyltrimethylammonium chloride, behenyltrimethylammonium chloride, distearyldimethylammonium chloride, and lanolin fatty acid aminopropylethyldimethylammonium ethyl sulfate.

[0311] Examples of the amine salt type include stearic acid diethylaminoethylamide lactate, dilaurylamine hydrochloride, and oleylamine lactate.

[0312] Examples of the amphoteric surfactant G4 (hereinafter abbreviated as G4) include betaine-type amphoteric surfactants and amino acid-type amphoteric surfactants.

[0313] Examples of betaine-type amphoteric surfactants include coconut oil fatty acid amidopropyl dimethylaminoacetic acid betaine, lauryl dimethylaminoacetic acid betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine, and lauryl hydroxysulfobetaine.

[0314] Examples of amino acid type amphoteric surfactants include sodium β-laurylaminopropionate.

[0315] Other emulsifying dispersants G5 (hereinafter abbreviated as G5) include, for example, reactive activators. The reactive activators are not particularly limited as long as they have radical reactivity, and can be appropriately selected depending on the purpose.

[0316] Examples of reactive activators include ADEKA REASOAP (registered trademark) SE-10N, SR-10, SR-20, SR-30, ER-20, and ER-30 (manufactured by ADEKA Corporation), AQUALON (registered trademark), HS-10, KH-05, KH-10, and KH-1025 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), ELEMINOL (registered trademark) JS-20 (manufactured by Sanyo Chemical Industries, Ltd.), LATEMULL (registered trademark) D-104, PD-420, and PD-430 (manufactured by Kao Corporation), and IONET (registered trademark) MO-200. (manufactured by Sanyo Chemical Industries, Ltd.), polyvinyl alcohol, starch or a derivative thereof, cellulose derivatives such as carboxymethyl cellulose, methyl cellulose, and hydroxyethyl cellulose, carboxyl group-containing (co)polymers such as poly(sodium acrylate), and emulsifying dispersants having urethane groups or ester groups described in U.S. Pat. No. 5,906,704 (for example, polycaprolactone polyol and polyether diol linked with polyisocyanate).

[0317] As surfactant G, from the viewpoint of stabilizing oil droplets during emulsification and dispersion, obtaining a desired shape, and sharpening the particle size distribution, G1, G2, G5, and combinations of these are preferred, and a combination of G1 and G5, and a combination of G2 and G5 are more preferred.

[0318] Examples of buffering agents include sodium acetate, sodium citrate, and sodium bicarbonate.

[0319] Examples of the protective colloid include water-soluble cellulose compounds and alkali metal salts of polymethacrylic acid.

[0320] In addition to the core resin (d1) and the shell resin (d2), the resin particles D may contain other resin components, an initiator (and its residue), a chain transfer agent, an antioxidant, a plasticizer, a preservative, a reducing agent, an organic solvent, etc.

[0321] Examples of other resin components include vinyl resins other than those used for the core resin (d1) and the shell resin (d2), polyurethane resins, epoxy resins, polyester resins, polyamide resins, polyimide resins, silicon resins, phenolic resins, melamine resins, urea resins, aniline resins, ionomer resins, polycarbonate resins, and the like.

[0322] Examples of the initiator (and its residue) include known radical polymerization initiators, and specific examples include persulfate initiators such as potassium persulfate and ammonium persulfate; azo initiators such as azobisisobutyronitrile; organic peroxides such as benzoyl peroxide, cumene hydroperoxide, tertiary butyl hydroperoxide, tertiary butyl peroxyisopropyl monocarbonate, and tertiary butyl peroxybenzoate; and hydrogen peroxide.

[0323] Examples of the chain transfer agent include n-dodecyl mercaptan, tert-dodecyl mercaptan, n-butyl mercaptan, 2-ethylhexyl thioglycolate, 2-mercaptoethanol, β-mercaptopropionic acid, and α-methylstyrene dimer.

[0324] Examples of antioxidants include phenol compounds, paraphenylenediamine, hydroquinone, organic sulfur compounds, and organic phosphorus compounds.

[0325] Examples of phenol compounds include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, stearyl-β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 2,2′-methylene-bis-(4-methyl-6-t-butylphenol), 2,2′-methylene-bis-(4-ethyl-6-t-butylphenol), 4,4′-thiobis-(3-methyl-6-t-butylphenol), 4,4′-butylidenebis-(3-methyl-6-t-butylphenol), t-butyl-6-t-butylphenol), 1,1,3-tris-(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane, bis[3,3'-bis(4'-hydroxy-3'-t-butylphenyl)butyric acid]glycol ester, tocopherol, etc.

[0326] Examples of paraphenylenediamines include N-phenyl-N'-isopropyl-p-phenylenediamine, N,N'-di-sec-butyl-p-phenylenediamine, N-phenyl-N-sec-butyl-p-phenylenediamine, N,N'-di-isopropyl-p-phenylenediamine, and N,N'-dimethyl-N,N'-di-t-butyl-p-phenylenediamine.

[0327] Examples of hydroquinones include 2,5-di-t-octylhydroquinone, 2,6-didodecylhydroquinone, 2-dodecylhydroquinone, 2-dodecyl-5-chlorohydroquinone, 2-t-octyl-5-methylhydroquinone, and 2-(2-octadecenyl)-5-methylhydroquinone.

[0328] Examples of the organic sulfur compounds include dilauryl-3,3'-thiodipropionate, distearyl-3,3'-thiodipropionate, and ditetradecyl-3,3'-thiodipropionate.

[0329] Examples of the organic phosphorus compound include triphenylphosphine, tri(nonylphenyl)phosphine, tri(dinonylphenyl)phosphine, tricresylphosphine, and tri(2,4-dibutylphenoxy)phosphine.

[0330] Examples of the plasticizer include phthalate esters, aliphatic dibasic acid esters, trimellitate esters, phosphate esters, and fatty acid esters.

[0331] Examples of phthalate esters include dibutyl phthalate, dioctyl phthalate, butyl benzyl phthalate, and diisodecyl phthalate.

[0332] Examples of the aliphatic dibasic acid ester include di-2-ethylhexyl adipate and 2-ethylhexyl sebacate.

[0333] Examples of trimellitic acid esters include tri-2-ethylhexyl trimellitate and trioctyl trimellitate.

[0334] Examples of the phosphate ester include triethyl phosphate, tri-2-ethylhexyl phosphate, and tricresyl phosphate.

[0335] An example of the fatty acid ester is butyl oleate.

[0336] Examples of preservatives include organic nitrogen-sulfur compounds and organic sulfur halides.

[0337] Examples of reducing agents include reducing organic compounds such as ascorbic acid, tartaric acid, citric acid, glucose, and formaldehyde sulfoxylate metal salts; and reducing inorganic compounds such as sodium thiosulfate, sodium sulfite, sodium bisulfite, and sodium metabisulfite.

[0338] Examples of organic solvents include ketone solvents such as acetone and methyl ethyl ketone; ester solvents such as ethyl acetate and γ-butyrolactone; ether solvents such as THF (tetrahydrofuran); amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone and N-methylcaprolactam; alcohol solvents such as isopropyl alcohol; and aromatic hydrocarbon solvents such as toluene and xylene.

[0339] The content of the resin particles is preferably 0.2% by mass to 5% by mass of the sum of resin (d1) and resin (d2) relative to the toner. When the sum of resin (d1) and resin (d2) is within the above range, the low-temperature fixability and heat-resistant storage stability are improved. When the sum of resin (d1) and resin (d2) relative to the toner is 0.2% by mass or more, the problem of deterioration in heat-resistant storage stability can be prevented, and when it is 5% by mass or less, the problem of deterioration in low-temperature fixability can be prevented.

[0340] The toner of this embodiment is used in a developer. Specifically, the developer contains at least the toner described above, and optionally contains other components such as a carrier. The developer may be a one-component developer or a two-component developer. However, when used in a high-speed printer that corresponds to the recent improvement in information processing speed, a two-component developer is preferred because of its improved lifespan.

[0341] The carrier is not particularly limited and can be appropriately selected depending on the purpose, but it is preferable that the carrier has a core material and a resin layer that covers the core material.

[0342] The material for the core is not particularly limited and can be appropriately selected depending on the purpose. Examples include manganese-strontium based materials with a viscosity of 50 emu / g to 90 emu / g, and manganese-magnesium based materials with a viscosity of 50 emu / g to 90 emu / g.

[0343] To ensure image density, it is preferable to use a high-magnetization material such as iron powder of 100 emu / g or more, or magnetite of 75 emu / g to 120 emu / g. Furthermore, it is preferable to use a low-magnetization material such as a copper-zinc material of 30 emu / g to 80 emu / g, as this can reduce the impact of the developer in a standing state on the photoreceptor and is advantageous for achieving high image quality. These materials may be used alone or in combination of two or more.

[0344] The volume average particle size of the core material is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 10 μm to 150 μm, more preferably 40 μm to 100 μm.

[0345] If the core particle size is less than 10 μm, the amount of fine powder in the carrier increases, which can reduce the magnetization per particle and cause carrier scattering. On the other hand, if the core particle size is more than 150 μm, the specific surface area decreases, which can cause toner scattering, and in full-color printers with many solid areas, the reproduction of solid areas can be particularly poor.

[0346] The toner of the present embodiment can be mixed with a carrier and used in a two-component developer. The content of the carrier in the two-component developer is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 90 parts by mass to 98 parts by mass, more preferably 93 parts by mass to 97 parts by mass, relative to 100 parts by mass of the two-component developer.

[0347] The developer of this embodiment can be suitably used for image formation by various known electrophotographic methods such as a magnetic one-component development method, a non-magnetic one-component development method, and a two-component development method.

[0348] As described above, in the toner of this embodiment, aggregates of multiple organic fine particles adhere to the surface of the base particle, the long diameter of the aggregates is at least three times the long diameter of the organic fine particles, and the proportion (occupancy) of the aggregates on the surface of the base particle is at least 10%. This makes it easier for gaps to form on the surface of the base particle, reducing the contact area between adjacent toner particles and between the toner and the substrate. This makes it easier for heat to be transferred to the toner during fixing, resulting in excellent low-temperature fixability.

[0349] Furthermore, in this embodiment, the aggregates having a major axis three times or more the major axis of the organic fine particles are present on the surface of the base particles at an occupancy rate of 10% or more, so that the aggregates attached to the surface of the base particles act as spacers, thereby reducing the adhesive force of the toner to the substrate, thereby suppressing the occurrence of filming and improving the cleaning properties of the toner.

[0350] Furthermore, in this embodiment, the average circularity of the aggregates adhering to the surface of the base particles is 0.9 or more, so that the aggregates are close to spherical. From this perspective, gaps are more likely to form on the surface of the base particles, reducing the contact area between adjacent toner particles and between the toner and the substrate. This makes it easier for heat to be transferred to the toner during fixing, improving the low-temperature fixability of the toner.

[0351] In the toner of the present embodiment, as described above, the organic fine particles constituting the aggregates attached to the surface of the base particles have a core resin and a shell resin that covers at least a part of the surface of the core resin, thereby improving both the low-temperature fixability and the cleanability. Endurance The heat preservation property can be improved.

[0352] In the toner of this embodiment, as described above, the shell resin constituting the organic fine particles contains a styrene-acrylic resin, which makes it easier for heat to be transferred to the toner during fixing and further reduces the adhesive force, thereby further improving the cleaning ability while maintaining excellent low-temperature fixing ability.

[0353] In the toner of this embodiment, as described above, the ratio of the aggregates made up of organic fine particles to the surface of the base particles is 60% to 80%, which further reduces the adhesive strength of the toner, thereby further improving the cleaning ability while maintaining excellent low-temperature fixability.

[0354] In the toner of this embodiment, as described above, the average circularity of the aggregates is 0.94 to 0.98, which makes the aggregates closer to spheres. This makes it easier for gaps to form on the surfaces of the base particles, further reducing the contact areas between adjacent toner particles and between the toner and the substrate, thereby further improving the low-temperature fixability of the toner.

[0355] In the toner of this embodiment, as described above, the standard deviation of the distance between adjacent organic fine particles on the surface of the base particle is 500 nm or less, so that the variation in the distance between the organic fine particles is reduced. but This reduces the size of the resin particles, preventing them from adhering locally to the surface of the base particles. This makes it easier for heat to be transmitted uniformly to the toner during fixing. Ku This further improves the low temperature fixability, and the toner adhesion is further reduced, further improving the cleaning properties.

[0356] In the toner of this embodiment, as described above, the volume average particle size of the aggregates made up of organic fine particles is 70 nm or more and 200 nm or less, which enhances the spacer function of the aggregates attached to the surface of the base particles, thereby further reducing the adhesive force of the toner and further improving the cleaning performance.

[0357] <Toner manufacturing method> The method for producing the toner according to the present embodiment is the method for producing the toner described above. The toner manufacturing method includes a composite particle forming step and a removing step, and may further include other steps as necessary.

[0358] [Composite particle formation process] The composite particle forming step is a step in which organic fine particles (resin fine particles) are attached to the surfaces of toner base particles to form composite particles.

[0359] Examples of methods for forming composite particles include a known dissolution suspension method in which an oil phase containing components of toner base particles such as a binder resin, a colorant, and a wax is dispersed in an aqueous medium containing resin fine particles to form granules.

[0360] As an example of the solution suspension method, a method of forming composite particles while generating a polyester resin through an elongation reaction and / or crosslinking reaction between a prepolymer and a curing agent is shown. In this method, an aqueous medium (aqueous phase) is prepared, an oil phase containing a toner base particle material is prepared, the toner base particle material is emulsified or dispersed, and the organic solvent is removed.

[0361] The aqueous medium (aqueous phase) can be prepared, for example, by dispersing resin fine particles in the aqueous medium. The amount of resin fine particles added to the aqueous medium is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.5 to 10 parts by mass per 100 parts by mass of the aqueous medium.

[0362] The aqueous medium is not particularly limited and can be appropriately selected depending on the purpose. Examples include water, a solvent miscible with water, and a mixture thereof. These may be used alone or in combination of two or more. Among these, water is preferred.

[0363] The water-miscible solvent is not particularly limited and can be appropriately selected depending on the purpose. Examples of the water-miscible solvent include alcohol, dimethylformamide, tetrahydrofuran, cellosolves, and lower ketones. Examples of the alcohol include methanol, isopropanol, and ethylene glycol. Examples of the lower ketone include acetone and methyl ethyl ketone.

[0364] The oil phase can be prepared by dissolving or dispersing the toner base particle material, which contains a binder resin, a colorant, and a wax, and further contains a curing agent, etc., as required, in an organic solvent.

[0365] The organic solvent is not particularly limited and can be appropriately selected depending on the purpose, but organic solvents having a boiling point of less than 150° C. are preferred in terms of ease of removal.

[0366] Examples of organic solvents having a boiling point of less than 150°C include toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, methyl ethyl ketone, and methyl isobutyl ketone.

[0367] These organic solvents having a boiling point of less than 150° C. may be used alone or in combination of two or more. Among these, ethyl acetate, toluene, xylene, benzene, methylene chloride, 1,2-dichloroethane, chloroform, carbon tetrachloride, etc. are preferred, and ethyl acetate is more preferred.

[0368] The toner base particle material can be emulsified or dispersed by dispersing an oil phase containing the toner base particle material in an aqueous medium, and during the emulsification or dispersion of the toner base particle material, the curing agent and the prepolymer can undergo an elongation reaction and / or a crosslinking reaction.

[0369] The reaction conditions (reaction time, reaction temperature) for producing the prepolymer are not particularly limited and can be appropriately selected depending on the combination of the curing agent and the prepolymer. The reaction time is preferably 10 minutes to 40 hours, more preferably 2 hours to 24 hours. The reaction temperature is preferably 0°C to 150°C, more preferably 40°C to 98°C.

[0370] The method for stably forming a dispersion containing a prepolymer in an aqueous medium is not particularly limited and can be appropriately selected depending on the purpose. For example, there is a method in which an oil phase prepared by dissolving or dispersing a toner base particle material in a solvent is added to an aqueous medium phase, and the oil phase is dispersed by shear force.

[0371] The dispersing machine for dispersion is not particularly limited and can be appropriately selected depending on the purpose. Examples of such dispersing machines include low-speed shear dispersing machines, high-speed shear dispersing machines, friction dispersing machines, high-pressure jet dispersing machines, and ultrasonic dispersing machines. Among these, high-speed shear dispersing machines are preferred because they can control the particle size of the dispersion (oil droplets) to 2 μm to 20 μm.

[0372] When a high-speed shear disperser is used, conditions such as the rotation speed, dispersion time, dispersion temperature, etc. can be appropriately selected depending on the purpose. The rotation speed is preferably 1,000 rpm to 30,000 rpm, more preferably 5,000 rpm to 20,000 rpm.

[0373] In the case of a batch method, the dispersion time is preferably 0.1 to 5 minutes. The dispersion temperature under pressure is preferably 0 to 150°C, more preferably 40 to 98°C. Generally, the higher the dispersion temperature, the easier the dispersion.

[0374] The amount of the aqueous medium used when emulsifying or dispersing the toner base particle material is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 50 parts by weight to 2,000 parts by weight, and more preferably 100 parts by weight to 1,000 parts by weight, per 100 parts by weight of the toner base particle material.

[0375] If the amount of the aqueous medium used is less than 50 parts by mass, the dispersion state of the toner base particle material may become poor, and toner base particles with the specified particle diameter may not be obtained, whereas if the amount of the aqueous medium used is more than 2,000 parts by mass, the production cost may become high.

[0376] When emulsifying or dispersing the oil phase containing the toner base particle material, it is preferable to use a dispersant from the viewpoint of stabilizing the dispersed matter such as oil droplets, forming them into a desired shape, and sharpening the particle size distribution.

[0377] The dispersant is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include surfactants, poorly water-soluble inorganic compound dispersants, and polymeric protective colloids. These may be used alone or in combination of two or more. Among these, surfactants are preferred.

[0378] The surfactant is not particularly limited and can be appropriately selected depending on the purpose. Examples of surfactants that can be used include anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants. Examples of anionic surfactants include alkylbenzene sulfonates, α-olefin sulfonates, and phosphate esters. Among these, those having a fluoroalkyl group are preferred.

[0379] The organic solvent can be removed by removing the organic solvent from a dispersion such as an emulsified slurry. The method for removing the organic solvent is not particularly limited and can be appropriately selected depending on the purpose. Examples include a method in which the temperature of the entire reaction system is gradually increased to evaporate the organic solvent in the oil droplets, and a method in which the dispersion is sprayed into a dry atmosphere to remove the organic solvent in the oil droplets. Composite particles are formed when the organic solvent is removed.

[0380] [Removal process] The removal step is a step of removing at least a part of the organic fine particles (resin fine particles) from the composite particles. In the removal step, it is preferable to remove a part or all of the shell resin (resin (d2)) in the resin fine particles.

[0381] An example of the step of removing at least a portion of the resin fine particles is a washing step of washing the composite particles. Therefore, the removing step can also be called a washing step.

[0382] In the removal step (hereinafter, sometimes referred to as a washing step), examples of a method for removing part or all of the resin (d2) include a method for removing part or all of the resin (d2) by a chemical method.

[0383] An example of the chemical method is washing the composite particles with a basic aqueous solution, which can dissolve part or all of the shell resin (d2).

[0384] By carrying out the washing step, the above-mentioned toner is obtained.

[0385] The basic aqueous solution is not particularly limited as long as it is basic, and can be appropriately selected depending on the purpose. Examples of basic aqueous solutions include aqueous solutions of alkali metal hydroxides such as potassium hydroxide and sodium hydroxide, and ammonia. These may be used alone or in combination of two or more. Among these, potassium hydroxide and sodium hydroxide are preferred from the viewpoint of facilitating dissolution of the shell resin (d2).

[0386] The pH of the basic aqueous solution is preferably 8 to 14, and more preferably 10 to 12.

[0387] The composite particles and the alkaline aqueous solution in the washing step can be mixed by, for example, adding a basic aqueous solution dropwise to the composite slurry under stirring. After the basic aqueous solution is added dropwise, an acidic aqueous solution may be added dropwise to neutralize the mixture.

[0388] The other steps are not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include a drying step and a classification step.

[0389] The drying step is not particularly limited as long as it can remove the solvent from the composite particles, and can be appropriately selected depending on the purpose.

[0390] The classification step may be carried out by removing fine particles in a liquid using a cyclone, decanter, centrifugal separation, or the like, or the classification operation may be carried out after drying.

[0391] The obtained composite particles may be mixed with particles of an external additive, a charge control agent, etc. In this case, by applying a mechanical impact force, it is possible to prevent particles of the external additive, etc. from being detached from the surface of the toner base particles.

[0392] The method for applying the mechanical impact force is not particularly limited and can be appropriately selected depending on the purpose. Examples include a method of applying an impact force to the mixture using blades rotating at high speed, and a method of introducing the mixture into a high-speed air stream and accelerating it to cause particles to collide with each other or with an appropriate collision plate.

[0393] The device used in this method of applying mechanical impact force is not particularly limited and can be appropriately selected depending on the purpose. Examples include Angmill (registered trademark) (manufactured by Hosokawa Micron Corporation), a device obtained by modifying I-type mill (manufactured by Nippon Pneumatic Co., Ltd.) to reduce the grinding air pressure, a Hybridization System (manufactured by Nara Machinery Works), a Kryptron System (manufactured by Kawasaki Heavy Industries, Ltd.), and an automatic mortar.

[0394] The toner manufacturing method according to the present embodiment includes a composite particle forming step of adhering organic fine particles to the surface of base particles to form composite particles, and a removal step of removing at least a portion of the organic fine particles from the composite particles, thereby obtaining the toner. Furthermore, the obtained toner can have both excellent low-temperature fixability and cleanability, as described above.

[0395] In the toner manufacturing method according to this embodiment, as described above, the removal step is a step of washing using a basic aqueous solution, so that part or all of the shell resin can be dissolved, and part or all of the organic fine particles can be removed with high precision.

[0396] <Toner storage unit> The toner storage unit according to this embodiment stores the above-described toner. In this specification, the term "toner storage unit" refers to a unit that stores toner in a unit having a function of storing toner. Examples of the toner storage unit include a toner storage container, a developing unit, a process cartridge, and the like.

[0397] The toner container is a container that stores toner.

[0398] The developing unit has a means for containing and developing toner.

[0399] The process cartridge is a cartridge that integrates at least an image carrier and a developing means, contains toner, and is detachably mountable to an image forming apparatus. The process cartridge may further include at least one selected from a charging means, an exposure means, and a cleaning means.

[0400] An embodiment of a process cartridge is shown in Fig. 2 as an example of a toner storage container according to this embodiment. As shown in Fig. 2, the process cartridge of this embodiment incorporates a latent image carrier 101, a charging device 102, a developing device 104, and a cleaning unit 106, and may further include other means as necessary. In Fig. 2, reference numeral 103 denotes exposure light from an exposure device, and reference numeral 105 denotes recording paper.

[0401] The latent image carrier 101 may be the same as an electrostatic latent image carrier in an image forming apparatus described later, and the charging device 102 may be any charging member.

[0402] In the image forming process using the process cartridge shown in Figure 2, the latent image carrier 101 rotates in the direction of the arrow, and an electrostatic latent image corresponding to the exposed image is formed on its surface by charging it with a charging device 102 and exposing it to exposure light 103 from an exposure means (not shown).

[0403] This electrostatic latent image is developed with toner by a developing device 104, and the toner development is transferred to recording paper 105 by a transfer roller 107 and printed out. Next, the surface of the latent image carrier after the image transfer is cleaned by a cleaning unit 106, and further discharged by a discharge means (not shown), and the above operations are repeated again.

[0404] In the toner storage unit according to the present embodiment, the above-described toner is used, thereby achieving the effects obtained by the above-described toner. Specifically, by mounting the toner storage unit according to the present embodiment on an image forming apparatus and forming an image, the above-described toner is used to form an image, thereby achieving both excellent low-temperature fixability and cleanability.

[0405] <Image forming apparatus and image forming method> The image forming apparatus of the present embodiment has the toner storage unit described above, and at least an electrostatic latent image carrier, an electrostatic latent image forming unit, and a developing unit. The image forming apparatus of the present embodiment preferably further has other units as necessary.

[0406] The image forming method according to this embodiment includes at least an electrostatic latent image forming step and a development step, and may further include other steps as necessary.

[0407] The material, structure, and size of the electrostatic latent image carrier are not particularly limited and can be appropriately selected from known materials. Examples of materials for the electrostatic latent image carrier include inorganic photoconductors such as amorphous silicon and selenium, and organic photoconductors such as polysilane and phthalopolymethine. Among these, amorphous silicon is preferred in terms of long life.

[0408] The linear speed of the electrostatic latent image bearing member is preferably 300 mm / s or more.

[0409] The electrostatic latent image forming means is not particularly limited as long as it is a means for forming an electrostatic latent image on an electrostatic latent image carrier, and can be appropriately selected depending on the purpose. Examples of the electrostatic latent image forming means include a means having at least a charging member for charging the surface of the electrostatic latent image carrier and an exposure member for imagewise exposing the surface of the electrostatic latent image carrier.

[0410] The electrostatic latent image forming step is not particularly limited as long as it is a step of forming an electrostatic latent image on an electrostatic latent image bearing member, and can be appropriately selected depending on the purpose. The electrostatic latent image forming step can be carried out, for example, by charging the surface of the electrostatic latent image bearing member and then exposing it to light in an imagewise manner, and can be carried out using the electrostatic latent image forming means constituting the image forming apparatus described above.

[0411] The charging member is not particularly limited and can be appropriately selected depending on the purpose. Examples of the charging member include a known contact charger equipped with a conductive or semiconductive roller, brush, film, rubber blade, etc., and a non-contact charger using corona discharge such as a corotron or scorotron.

[0412] Charging can be carried out, for example, by applying a voltage to the surface of the electrostatic latent image bearing member using a charging member.

[0413] The shape of the charging member may be any shape, such as a roller, a magnetic brush, a fur brush, etc., and can be selected according to the specifications and shape of the image forming apparatus.

[0414] The charging member is not limited to a contact-type charging member, but it is preferable to use a contact-type charging member because it allows an image forming apparatus to be obtained in which the amount of ozone generated from the charging member is reduced.

[0415] The exposing member is not particularly limited and can be appropriately selected depending on the purpose as long as it can expose the surface of the electrostatic latent image carrier charged by the charging member in the shape of an image to be formed. Examples of the exposing member include various exposing members such as a copying optical system, a rod lens array system, a laser optical system, and a liquid crystal shutter optical system.

[0416] The light source used in the exposure member is not particularly limited and can be appropriately selected depending on the purpose. Examples of the light source used in the exposure member include general light-emitting materials such as fluorescent lamps, tungsten lamps, halogen lamps, mercury lamps, sodium lamps, light-emitting diodes (LEDs), semiconductor lasers (LDs), and electroluminescence (EL).

[0417] In order to irradiate only light in a desired wavelength range, various filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used.

[0418] The exposure can be carried out, for example, by exposing the surface of the electrostatic latent image bearing member to light in an imagewise manner using an exposure member.

[0419] In this embodiment, a backlight system may be employed in which exposure is performed imagewise from the back side of the electrostatic latent image carrier.

[0420] The developing means is not particularly limited as long as it is a developing means equipped with toner that develops an electrostatic latent image formed on an electrostatic latent image carrier to form a toner image, which is a visible image, and can be selected appropriately depending on the purpose.

[0421] The developing step is not particularly limited as long as it is a step of developing an electrostatic latent image formed on an electrostatic latent image carrier using a toner to form a visible toner image, and can be appropriately selected depending on the purpose. For example, the developing step can be performed by a developing means constituting the image forming apparatus described above.

[0422] As the developing means, a developing device having an agitator that charges the toner by frictional agitation, a magnetic field generating means fixed inside, and a rotatable developer carrier that carries a developer containing toner on its surface is preferred.

[0423] Examples of other means in the image forming apparatus include a transfer means, a fixing means, a cleaning means, a discharging means, a recycling means, and a control means.

[0424] Examples of other steps in the image forming method include a transfer step, a fixing step, a cleaning step, a discharging step, a recycling step, and a control step.

[0425] The transfer means is not particularly limited as long as it is a means for transferring a visible image onto a recording medium, and can be appropriately selected depending on the purpose. A preferred embodiment of the transfer means includes a primary transfer means for transferring the visible image onto an intermediate transfer body to form a composite transfer image, and a secondary transfer means for transferring the composite transfer image onto a recording medium.

[0426] The transfer step is not particularly limited as long as it is a step of transferring a visible image onto a recording medium, and can be appropriately selected depending on the purpose. However, a preferred embodiment is one in which an intermediate transfer member is used, a visible image is primarily transferred onto the intermediate transfer member, and then the visible image is secondarily transferred onto a recording medium.

[0427] The transfer step can be carried out, for example, by charging the visible image on the photosensitive member using a transfer charger, and can be carried out by the transfer means constituting the image forming apparatus described above.

[0428] Here, when the image to be secondarily transferred onto the recording medium is a color image made up of toners of multiple colors, the transfer means can be configured to sequentially overlay toners of each color on the intermediate transfer body to form an image on the intermediate transfer body, and the intermediate transfer means can secondarily transfer the image on the intermediate transfer body all at once onto the recording medium.

[0429] The intermediate transfer member is not particularly limited and can be appropriately selected from known transfer members depending on the purpose, and a suitable example is a transfer belt.

[0430] The transfer means (primary transfer means, secondary transfer means) preferably includes at least a transfer device that peels and charges the visible image formed on the photosensitive member onto the recording medium. Examples of the transfer device include a corona transfer device that uses corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, and an adhesive transfer device.

[0431] The recording medium is typically plain paper, but there are no particular restrictions as long as it is capable of transferring the unfixed image after development, and it can be selected appropriately depending on the purpose. PET base for overhead projectors can also be used.

[0432] The fixing means is not particularly limited as long as it is a means for fixing the transferred image transferred to the recording medium, and can be appropriately selected depending on the purpose. For example, a known heating and pressing member is preferable as the fixing means. Examples of the heating and pressing member include a combination of a heating roller and a pressing roller, and a combination of a heating roller, a pressing roller, and an endless belt.

[0433] The fixing step is not particularly limited as long as it is a step of fixing the visible image transferred to the recording medium, and can be appropriately selected depending on the purpose. The fixing step may be performed, for example, for each color toner transferred to the recording medium, or may be performed simultaneously for each color toner in a stacked state.

[0434] The fixing step can be carried out by the fixing means constituting the image forming apparatus described above.

[0435] The heating temperature in the heating and pressing member is preferably 80°C to 200°C.

[0436] In this embodiment, depending on the purpose, for example, a known optical fixing device may be used together with or instead of the fixing means.

[0437] The surface pressure in the fixing step is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 10 N / cm 2 ~80N / cm 2 It is preferable that:

[0438] The cleaning means is not particularly limited as long as it can remove toner remaining on the photoreceptor, and can be appropriately selected depending on the purpose. Examples of cleaning means include magnetic brush cleaners, electrostatic brush cleaners, magnetic roller cleaners, blade cleaners, brush cleaners, and web cleaners.

[0439] The cleaning step is not particularly limited as long as it can remove the toner remaining on the photoreceptor, and can be appropriately selected depending on the purpose. The cleaning step can be performed, for example, by the cleaning unit constituting the image forming apparatus described above.

[0440] The discharging means is not particularly limited as long as it is a means for discharging the photosensitive member by applying a discharging bias, and can be appropriately selected depending on the purpose. For example, a discharging lamp can be used.

[0441] The charge removal step is not particularly limited as long as it is a step of removing static electricity by applying a static removal bias to the photoreceptor, and can be appropriately selected depending on the purpose. The charge removal step can be performed, for example, by a static removal unit included in the image forming apparatus described above.

[0442] The recycling means is not particularly limited as long as it is a means for recycling the toner removed in the cleaning step into the developing device, and can be appropriately selected depending on the purpose, and examples thereof include known transport means.

[0443] The recycling process is not particularly limited as long as it is a process for recycling the toner removed by the cleaning process into the developing device, and can be selected appropriately depending on the purpose. For example, it can be carried out by a recycling means constituting the image forming apparatus described above.

[0444] As an example of the image forming apparatus of this embodiment, an apparatus for carrying out the image forming method of this embodiment is shown in Fig. 3. Although a printer is shown as an example of the image forming apparatus of this embodiment, the image forming apparatus is not particularly limited as long as it is capable of forming an image using toner, such as a copier, facsimile, or multifunction machine.

[0445] The image forming apparatus of this embodiment includes a paper feed unit 210, a conveying unit 220, an image forming unit 230, a transfer unit 240, and a fixing unit 250.

[0446] The paper feed section 210 includes a paper feed cassette 211 in which the paper P to be fed is stacked, and a paper feed roller 212 that feeds the paper P stacked in the paper feed cassette 211 one sheet at a time.

[0447] The transport unit 220 includes a roller 221, a pair of timing rollers 222, and a paper discharge roller 223. The roller 221 transports the paper P fed by the paper feed roller 212 toward the transfer unit 240. The pair of timing rollers 222 wait while pinching the leading edge of the paper P fed by the roller 221, and send the paper to the transfer unit 240 at a predetermined timing. The paper discharge roller 223 discharges the paper P with the fixed color toner image onto a paper discharge tray 224.

[0448] As shown in Figure 3, the image forming section 230 is equipped with, from left to right at a predetermined interval, an image forming unit Y, an image forming unit C, an image forming unit M, an image forming unit K, and an exposure device 233.

[0449] Image forming unit Y forms an image using a developer containing yellow toner. Image forming unit C uses a developer containing cyan toner. Image forming unit M uses a developer containing magenta toner. Image forming unit K uses a developer containing black toner.

[0450] It should be noted that when referring to any of the image forming units (Y, C, M, K), it is referred to as an image forming unit.

[0451] The developer contains toner and carrier. The four image forming units (Y, C, M, K) have substantially the same mechanical configuration, except for the developer used in each.

[0452] The image forming units (Y, C, M, K) are provided so as to be rotatable clockwise in Fig. 3. The image forming units (Y, C, M, K) include photosensitive drums (231Y, 231C, 231M, 231K), chargers (232Y, 232C, 232M, 232K), developing units (180Y, 180C, 180M, 180K), and cleaners (236Y, 236C, 236M, 236K).

[0453] Electrostatic latent images and toner images are formed on the photosensitive drums (231Y, 231C, 231M, 231K). The chargers (232Y, 232C, 232M, 232K) uniformly charge the surfaces of the photosensitive drums (231Y, 231C, 231M, 231K).

[0454] The developing units (180Y, 180C, 180M, 180K) develop the electrostatic latent images formed on the surfaces of the photosensitive drums (231Y, 231C, 231M, 231K) by the exposure unit 233 into toner images using toner of each color. The cleaning units (236Y, 236C, 236M, 236K) remove the toner remaining on the surfaces of the photosensitive drums (231Y, 231C, 231M, 231K).

[0455] The image forming units (Y, C, M, K) are also provided with toner cartridges (234Y, 234C, 234M, 234K) and sub-hoppers (160Y, 160C, 160M, 160K).

[0456] The toner cartridges (234Y, 234C, 234M, 234K) contain toner of each color. The sub-hoppers (160Y, 160C, 160M, 160K) are used to replenish the toner supplied from the toner cartridges (234Y, 234C, 234M, 234K).

[0457] The toner contained in the toner cartridge 234 is discharged by a suction pump (not shown) and supplied to the sub-hopper 160 via a supply pipe (not shown). The sub-hopper 160 transports the toner supplied from the toner cartridge 234 and supplies it to the developing device 180. The developing device 180 uses the toner supplied by the sub-hopper 160 to develop the electrostatic latent image formed on the photosensitive drum 231.

[0458] It should be noted that, when referring to any one of the photosensitive drums (231Y, 231C, 231M, 231K), it will be referred to as the photosensitive drum 231.

[0459] Furthermore, when referring to any one of the chargers (232Y, 232C, 232M, 232K), it will be referred to as charger 232.

[0460] Furthermore, any one of the toner cartridges (234Y, 234C, 234M, 234K) will be referred to as toner cartridge 234.

[0461] Furthermore, when referring to any one of the sub-hoppers (160Y, 160C, 160M, 160K), it will be referred to as sub-hopper 160.

[0462] Furthermore, when referring to any one of the developers (180Y, 180C, 180M, 180K), it will be referred to as developer 180.

[0463] Furthermore, when referring to any one of the cleaners (236Y, 236C, 236M, 236K), it will be referred to as cleaner 236.

[0464] The photosensitive drum 231 is not particularly limited, but examples thereof include inorganic photosensitive drums such as amorphous silicon photosensitive drums and selenium photosensitive drums, and organic photosensitive drums such as polysilane photosensitive drums and phthalopolymethine photosensitive drums, etc. Among these, amorphous silicon photosensitive drums are preferred in terms of long life.

[0465] The charger 232 is an example of a charging member that charges the surface of the electrostatic latent image carrier as the electrostatic latent image forming means, and the above-mentioned contact charger, non-contact charger, etc. can be used.

[0466] The charger 232 is preferably disposed in contact with or out of contact with the photosensitive drum 231, and charges the surface of the photosensitive drum 231 by applying a superimposed DC and AC voltage.

[0467] Furthermore, the charger 232 is a charging roller that is arranged close to the photosensitive drum 231 but without contacting it via a gap tape, and it is preferable that the surface of the photosensitive drum 231 is charged by applying a DC voltage and an AC voltage superimposed on the charging roller.

[0468] The exposure device 233 irradiates the photosensitive drum 231 with laser light L emitted from a light source 233a based on image information, by reflecting the light on a polygon mirror 233b (233bY, 233bC, 233bM, 233bK) that is rotationally driven by a motor.

[0469] The exposure device 233 is not particularly limited as long as it can expose the surface of the photosensitive drum 231 charged by the charger 232 in the form of an image to be formed. Examples of the exposure device 233 include various exposure devices such as a copying optical system, a rod lens array system, a laser optical system, and a liquid crystal shutter optical system.

[0470] It is also possible to employ a backlight system in which exposure is performed imagewise from the back side of the photosensitive drum 231 .

[0471] The developing device 180 is not particularly limited as long as it is capable of developing using a developer. The developing device 180 is preferably a developing device that stores a developer and applies the developer to the electrostatic latent image in a contact or non-contact manner, and more preferably a developing device that includes a developer container.

[0472] Developer 180 may be a single color developer or a multi-color developer.

[0473] There are no particular limitations on the cleaner 236, as long as it is capable of removing toner remaining on the surface of the photosensitive drum 231. As the cleaner 236, a cleaner equipped with a cleaning member such as a magnetic brush cleaner, an electrostatic brush cleaner, a magnetic roller cleaner, a blade cleaner, a brush cleaner, or a web cleaner is preferred.

[0474] The photosensitive drum 231 from which the toner has been removed by the cleaner 236 is then neutralized to remove any remaining potential, thereby completing the series of image forming processes performed on the photosensitive drum 231.

[0475] The transfer unit 240 includes a drive roller 241 , a driven roller 242 , an intermediate transfer belt 243 , primary transfer rollers ( 244 Y, 244 C, 244 M, 244 K), a secondary opposing roller 245 , and a secondary transfer roller 246 .

[0476] The drive roller 241 is provided on the toner cartridge 234Y side of the image forming unit (Y), and the driven roller 242 is provided on the toner cartridge 234K side of the image forming unit (K).

[0477] 3 in response to the drive of drive roller 241. Primary transfer rollers (244Y, 244C, 244M, 244K) are provided opposite photosensitive drum 231 with intermediate transfer belt 243 in between. Secondary opposing roller 245 and secondary transfer roller 246 are provided opposite each other with intermediate transfer belt 243 in between at the position where the toner image is transferred to paper.

[0478] It should be noted that, when referring to any one of the primary transfer rollers (244Y, 244C, 244M, 244K), it will be referred to as the primary transfer roller 244.

[0479] A primary transfer bias having a polarity opposite to that of the toner is applied to the primary transfer roller 244. Meanwhile, the intermediate transfer belt 243 is sandwiched between the primary transfer roller 244 and the photosensitive drum 231 to form a primary transfer nip.

[0480] As a result, the toner images of each color formed on the surface of the photosensitive drum 231 are transferred (primary transfer) onto the intermediate transfer belt 243. In this case, as the intermediate transfer belt 243 rotates in the direction of the arrow in the figure, the toner images of each color formed on the photosensitive drums (231Y, 231C, 231M, 231K) are transferred sequentially onto the intermediate transfer belt 243 to form a color toner image.

[0481] A secondary transfer bias is applied to the secondary transfer roller 246 of the transfer unit 240. As a result, the color toner image formed on the intermediate transfer belt 243 is transferred (secondary transfer) to the paper P sandwiched between the secondary transfer roller 246 and the secondary opposing roller 245 at the secondary transfer nip.

[0482] The fixing device 250 includes a fixing belt 251 with an internal heater that heats the paper P, and a pressure roller 252 that forms a nip by applying pressure to the fixing belt 251 while allowing it to rotate. This applies heat and pressure to the color toner image on the paper P, fixing the color toner image. The paper P with the fixed color toner image is discharged to a paper discharge tray 224 by a paper discharge roller 223, completing the image formation process.

[0483] As described above, the image forming apparatus according to this embodiment has a toner storage unit, thereby achieving the effects obtained by the toner storage unit. Specifically, by using the image forming apparatus according to this embodiment, the toner storage unit containing the toner is attached to the image forming apparatus, and image formation is performed using the toner, thereby achieving both excellent low-temperature fixability and cleanability.

[0484] Furthermore, as described above, the image forming method according to this embodiment includes an electrostatic latent image forming step of forming an electrostatic latent image on an electrostatic latent image carrier, a developing step of developing the electrostatic latent image formed on the electrostatic latent image carrier with toner to form a toner image, a transfer step of transferring the toner image formed on the electrostatic latent image carrier to a medium, and a fixing step of fixing the toner image transferred to the medium.

[0485] As a result, in the image forming method according to the present embodiment, an image is formed using the above-described toner, and therefore, both excellent low-temperature fixability and cleanability can be achieved. [Example]

[0486] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In the following, "%" is based on mass unless otherwise specified. In addition, various tests and evaluations were performed according to the following methods.

[0487] (Production Example 1) [Synthesis of amorphous polyester (low molecular weight polyester) resin] A 5-liter four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple was charged with 229 parts by mass of bisphenol A ethylene oxide 2-mol adduct, 529 parts by mass of bisphenol A propylene oxide 2-mol adduct, 208 parts by mass of terephthalic acid, 46 parts by mass of adipic acid, and 2 parts by mass of dibutyltin oxide, and the mixture was reacted at 230°C under normal pressure for 7 hours, and then further reacted under a reduced pressure of 10 mmHg to 15 mmHg for 4 hours. After that, 44 parts by mass of trimellitic anhydride was charged into the reaction vessel, and the mixture was reacted at 180°C under normal pressure for 2 hours to obtain a non-crystalline polyester (low molecular weight polyester) resin.

[0488] (Production Example 2) [Synthesis of crystalline polyester resin] A 5-liter four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple was charged with 2,300 parts by mass of 1,6-hexanediol, 2,530 parts by mass of fumaric acid, 291 parts by mass of trimellitic anhydride, and 4.9 parts by mass of hydroquinone, and the mixture was reacted at 160°C for 5 hours, then heated to 200°C and reacted for 1 hour, and further reacted at 8.3 kPa for 1 hour to obtain a [crystalline polyester resin].

[0489] (Production Example 3) [Synthesis of Polyester Prepolymer] Into a reaction vessel equipped with a condenser, a stirrer, and a nitrogen inlet tube, 682 parts by mass of ethylene oxide 2-mol bisphenol A adduct, 81 parts by mass of propylene oxide 2-mol bisphenol A adduct, 283 parts by mass of terephthalic acid, 22 parts by mass of trimellitic anhydride, and 2 parts by mass of dibutyltin oxide were placed, and the mixture was reacted at 230°C under normal pressure for 8 hours, and then further reacted at a reduced pressure of 10 mmHg to 15 mmHg for 5 hours to obtain an [intermediate polyester].

[0490] The [intermediate polyester] had a number average molecular weight Mn of 2,100, a weight average molecular weight Mw of 9,500, a glass transition temperature Tg of 55°C, an acid value of 0.5 KOHmg / g, and a hydroxyl value of 51 KOHmg / g. Next, 410 parts by mass of the [intermediate polyester], 89 parts by mass of isophorone diisocyanate, and 500 parts by mass of ethyl acetate were placed in a reaction vessel equipped with a condenser, a stirrer, and a nitrogen inlet tube, and reacted at 100°C for 5 hours to obtain a [prepolymer].

[0491] (Production Example 4) [Production of Aqueous Dispersion (W0-1) of Resin Fine Particles (A-1)] A reaction vessel equipped with a stirrer, a heating / cooling device, and a thermometer was charged with 3710 parts by mass of water and 200 parts by mass of polyoxyethylene-1-(allyloxymethyl) alkyl ether sulfate ester ammonium (Aqualon (registered trademark) KH-1025, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), and the mixture was stirred at 200 rpm to homogenize.

[0492] The homogenized mixture was heated to raise the system temperature to 75°C, and then 90 parts by mass of a 10% aqueous ammonium persulfate solution was added, followed by the dropwise addition of a mixed liquid consisting of 450 parts by mass of styrene, 250 parts by mass of butyl acrylate, and 300 parts by mass of methacrylic acid over a period of 4 hours.

[0493] After the dropwise addition, the mixture was aged at 75°C for 4 hours to obtain an aqueous dispersion (W0-1) of resin microparticles (A-1) containing resin (a1), which is a polymer copolymerized with a monomer and polyoxyethylene-1-(allyloxymethyl) alkyl ether sulfate ester ammonium.

[0494] The volume average particle size of the fine particles in the aqueous dispersion (W0-1) of resin fine particles (A-1) was measured using a dynamic light scattering particle size distribution analyzer (LB) and was found to be 15 nm. A portion of the aqueous dispersion (W0-1) of resin fine particles (A-1) was dried to isolate resin (a1-1). The glass transition temperature (Tg) of the resin component was 53°C and the acid value was 195 mgKOH / g.

[0495] (Production Example 5) [Preparation of Aqueous Dispersion (W0-2) of Resin Fine Particles (A-2)] A reaction vessel equipped with a stirrer, a heating / cooling device, and a thermometer was charged with 3,760 parts by mass of water and 150 parts by mass of polyoxyethylene-1-(allyloxymethyl) alkyl ether sulfate ester ammonium (Aqualon KH-1025, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and the mixture was stirred at 200 rpm to homogenize.

[0496] The homogenized mixture was heated to raise the system temperature to 75°C, and then 90 parts by mass of a 10% aqueous ammonium persulfate solution was added, followed by the dropwise addition of a mixed liquid consisting of 430 parts by mass of styrene, 270 parts by mass of butyl acrylate, and 300 parts by mass of methacrylic acid over 4 hours.

[0497] After the dropwise addition, the mixture was aged for 4 hours at 75°C to obtain an aqueous dispersion (W0-2) of resin microparticles (A-2) containing resin (a2), which is a polymer obtained by copolymerizing a monomer and polyoxyethylene-1-(allyloxymethyl) alkyl ether sulfate ester ammonium. The volume average particle size of the microparticles in the aqueous dispersion (W0-2) of resin microparticles (A-2) was measured in the same manner as in Production Example 4 and was found to be 30 nm.

[0498] A portion of the aqueous dispersion (W0-2) of resin fine particles (A-2) was dried to isolate resin (a2), which had a glass transition temperature (Tg) of 53°C and an acid value of 195 mgKOH / g.

[0499] (Production Example 6) [Production of Aqueous Dispersion (W0-3) of Resin Fine Particles (A-3)] A reaction vessel equipped with a stirrer, a heating / cooling device, and a thermometer was charged with 3,810 parts by mass of water and 100 parts by mass of polyoxyethylene-1-(allyloxymethyl) alkyl ether sulfate ester ammonium (Aqualon KH-1025, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and the mixture was stirred at 200 rpm to homogenize.

[0500] The homogenized mixture was heated to raise the system temperature to 75°C, and then 90 parts by mass of a 10% aqueous ammonium persulfate solution was added, followed by the dropwise addition of a mixed liquid consisting of 400 parts by mass of styrene, 300 parts by mass of butyl acrylate, and 300 parts by mass of methacrylic acid over a period of 4 hours.

[0501] After the dropwise addition, the mixture was aged for 4 hours at 75°C to obtain an aqueous dispersion (W0-3) of resin microparticles (A-3) containing resin (a3), which is a polymer obtained by copolymerizing a monomer and polyoxyethylene-1-(allyloxymethyl) alkyl ether sulfate ester ammonium. The volume average particle size of the microparticles in the aqueous dispersion (W0-3) of resin microparticles (A-3) was measured in the same manner as in Production Example 4 and was found to be 45 nm.

[0502] A portion of the aqueous dispersion (W0-3) of resin fine particles (A-3) was dried to isolate resin (a3), which had a glass transition temperature (Tg) of 53°C and an acid value of 195 mgKOH / g.

[0503] (Production Example 7) [Production of Aqueous Dispersion (W-1) of Resin Fine Particles (B-1)] Next, 667 parts by mass of the aqueous dispersion (W0-1) and 248 parts by mass of water were placed in a reaction vessel equipped with a stirrer, a heating / cooling device, and a thermometer, and 0.267 parts by mass of tert-butyl hydroperoxide (Perbutyl (registered trademark) H, manufactured by NOF Corporation) was added. The system was then heated to raise the temperature within the system to 70°C, and 43.3 parts by mass of styrene, 17.5 parts by mass of butyl acrylate, 5.8 parts by mass of 2-ethylhexyl acrylate, and 18.0 parts by mass of a 1% aqueous ascorbic acid solution were then added dropwise over 2 hours.

[0504] After the dropwise addition, the mixture was aged for 4 hours at 70°C to obtain an aqueous dispersion (W-1) of resin microparticles (B-1) containing resin (a1-1), a polymer formed by copolymerization of monomers using the resin microparticles in (W0-1) as seeds, and resin (a1) as constituent components within the same particle. The volume average particle size of the microparticles in the aqueous dispersion (W-1) was measured in the same manner as in Production Example 4 and was found to be 17 nm.

[0505] It was confirmed as follows that the aqueous dispersion (W-1) contained resin fine particles (B-1) containing the resin (a1-1) and the resin (a1) as constituent components in the same particle.

[0506] Specifically, 2 parts by mass of gelatin (Cook Gelatin (registered trademark), manufactured by Morinaga Milk Industry Co., Ltd.) was dissolved in 15 parts by mass of water heated to 95-100°C, and the gelatin solution was air-cooled to 40°C. The aqueous dispersion (W-1) was mixed with the gelatin solution in a 1:1 mass ratio, stirred well, and then cooled to 10°C for 1 hour to produce a hardened gel.

[0507] This gel was cut into 80 nm thick sections using an ultramicrotome (Leica Microsystems, Ultramicrotome UC7, FC7) at a temperature of -80°C. The sections were then stained with a 2% aqueous solution of ruthenium tetroxide for 5 minutes and then observed under a transmission electron microscope (Hitachi Technologies, H-7100).

[0508] (Production Example 8) [Production of Aqueous Dispersion (W-2) of Resin Fine Particles (B-2)] Next, 667 parts by mass of the aqueous dispersion (W0-3) and 248 parts by mass of water were placed in a reaction vessel equipped with a stirrer, a heating / cooling device, and a thermometer, and 0.267 parts by mass of tert-butyl hydroperoxide (Perbutyl H, manufactured by NOF Corporation) was added. The system was then heated to raise the temperature within the system to 70°C, and 43.3 parts by mass of styrene, 23.3 parts by mass of butyl acrylate, and 18.0 parts by mass of a 1% aqueous ascorbic acid solution were then added dropwise over 2 hours.

[0509] After the dropwise addition, the mixture was aged for 4 hours at 70°C to obtain a dispersion (W-2) of resin particles (B-2) containing resin (a3-1) and resin (a3), which are polymers formed by copolymerization of monomers using the resin particles in (W0-3) as seeds. The volume average particle size of the particles in the aqueous dispersion (W-2) was measured in the same manner as in Production Example 4 and was found to be 52 nm.

[0510] It was confirmed by the same method as in Production Example 7 that the aqueous dispersion (W-4) contained resin fine particles (B-5) containing resin (a3-1) and resin (a3) as constituent components in the same particle.

[0511] (Production Example 9) [Production of Aqueous Dispersion (W-3) of Resin Fine Particles (B-3)] Next, 667 parts by mass of the aqueous dispersion (W0-1) and 248 parts by mass of water were placed in a reaction vessel equipped with a stirrer, a heating / cooling device, and a thermometer, and 0.267 parts by mass of tert-butyl hydroperoxide (Perbutyl H, manufactured by NOF Corporation) was added. The system was then heated to raise the temperature within the system to 70°C, and 43.3 parts by mass of styrene, 23.3 parts by mass of 2-ethylhexyl acrylate, and 18.0 parts by mass of a 1% aqueous ascorbic acid solution were then added dropwise over 2 hours.

[0512] After the dropwise addition, the mixture was aged for 4 hours at 70°C to obtain a dispersion (W-3) of resin particles (B-3) containing resin (a1-3), a polymer formed by copolymerization of monomers using the resin particles in (W0-1) as seeds, and resin (a1) as constituents within the same particle. The volume average particle size of the particles in the aqueous dispersion (W-3) was measured in the same manner as in Production Example 4 and was found to be 17 nm.

[0513] It was confirmed by the same method as in Production Example 7 that the aqueous dispersion (W-3) contained resin fine particles (B-3) containing the resin (a1) and the resin (a1-3) as constituent components in the same particle.

[0514] (Production Example 10) [Production of Aqueous Dispersion (W-4) of Resin Fine Particles (B-4)] Next, 667 parts by mass of the aqueous dispersion (W0-2) and 248 parts by mass of water were placed in a reaction vessel equipped with a stirrer, a heating / cooling device, and a thermometer, and 0.267 parts by mass of tert-butyl hydroperoxide (Perbutyl H, manufactured by NOF Corporation) was added. The system was then heated to raise the temperature within the system to 70°C, and 43.3 parts by mass of styrene, 17.5 parts by mass of butyl acrylate, 5.8 parts by mass of 2-ethylhexyl acrylate, and 18.0 parts by mass of a 1% aqueous ascorbic acid solution were then added dropwise over 2 hours.

[0515] After the dropwise addition, the mixture was aged for 4 hours at 70°C to obtain a dispersion (W-4) of resin particles (B-4) containing resin (a2-1) and resin (a2), which are polymers formed by copolymerization of monomers using the resin particles in (W0-2) as seeds. The volume average particle size of the particles in the aqueous dispersion (W-4) was measured in the same manner as in Production Example 4 and was found to be 34 nm.

[0516] It was confirmed by the same method as in Production Example 7 that the aqueous dispersion (W-4) contained resin fine particles (B-4) containing resin (a2-1) and resin (a2) as constituent components in the same particle.

[0517] (Production Example 11) [Production of Aqueous Dispersion (W-5) of Resin Fine Particles (B-5)] Next, 667 parts by mass of the aqueous dispersion (W0-3) and 248 parts by mass of water were placed in a reaction vessel equipped with a stirrer, a heating / cooling device, and a thermometer, and 0.267 parts by mass of tert-butyl hydroperoxide (Perbutyl H, manufactured by NOF Corporation) was added. The system was then heated to raise the temperature within the system to 70°C, and 43.3 parts by mass of styrene, 23.3 parts by mass of butyl acrylate, and 18.0 parts by mass of a 1% aqueous ascorbic acid solution were then added dropwise over 2 hours.

[0518] After the dropwise addition, the mixture was aged for 4 hours at 70°C to obtain a dispersion (W-5) of resin particles (B-5) containing resin (a3-1), a polymer formed by copolymerization of monomers using the resin particles in (W0-3) as seeds, and resin (a3) as constituent components within the same particle. The volume average particle size of the particles in the aqueous dispersion (W-5) was measured in the same manner as in Production Example 4 and was found to be 52 nm.

[0519] It was confirmed by the same method as in Production Example 7 that the aqueous dispersion (W-4) contained resin fine particles (B-5) containing resin (a3-1) and resin (a3) as constituent components in the same particle.

[0520] (Production Example 12) [Preparation of Crystalline Polyester Resin Particle Dispersion (Polyester Particle Dispersion)] 20 parts by mass of polyester resin A, 70 parts by mass of ethyl acetate, and 30 parts by mass of methyl ethyl ketone were placed in a beaker and stirred at 10,000 rpm using a TK Homomixer (manufactured by Primix Corporation) to dissolve the mixture uniformly, thereby preparing a polyester resin solution (polyester particle dispersion).

[0521] Meanwhile, an aqueous medium was prepared by dissolving 0.5% of a dispersant (sodium dodecylbenzenesulfonate) and 0.5% of polyvinyl alcohol in 450 parts by mass of ion-exchanged water, and the polyester resin solution was suspended in the aqueous medium using a TK homomixer to form an O / W type emulsion.

[0522] The mixture was stirred for 30 minutes at a rotation speed of 12,000 rpm using a TK homomixer, and then heated while stirring at a rotation speed of 200 rpm using a TK homomixer to remove the mixed solvent, yielding a polyester particle dispersion with a volume average particle size of 110 nm.

[0523] (Manufacturing Example 13) [Preparation of Aqueous Dispersion of Resin Fine Particles B'] A reaction vessel equipped with a stirrer and a thermometer was charged with 683 parts by mass of water, 11 parts by mass of sodium salt of methacrylic acid ethylene oxide adduct sulfate (Eleminol (registered trademark) RS-30, manufactured by Sanyo Chemical Industries, Ltd.), 138 parts by mass of styrene, 138 parts by mass of methacrylic acid, and 1 part by mass of ammonium persulfate, and the mixture was stirred at 400 rpm for 15 minutes to prepare a white emulsion. The mixture was heated to an internal temperature of 75°C and allowed to react for 5 hours.

[0524] Furthermore, 30 parts by mass of a 1% aqueous solution of ammonium persulfate was added, and the mixture was aged at 75°C for 5 hours to obtain an aqueous dispersion of a vinyl resin (a copolymer of styrene-methacrylic acid-methacrylic acid ethylene oxide adduct sulfate ester sodium salt) [Aqueous Dispersion B'].

[0525] Example 1 [Preparation of Masterbatch (MB)] 1,200 parts by mass of water, 540 parts by mass of carbon black (PRINTEX (registered trademark) 35, manufactured by Evonik Dexa, DBP oil absorption = 42 mL / 100 mg, pH = 9.5), and 1,200 parts by mass of [amorphous polyester resin] were added and mixed in a Henschel mixer (manufactured by Nippon Coke and Engineering Co., Ltd.). The mixture was kneaded using two rolls at 150°C for 30 minutes, then rolled and cooled, and pulverized in a pulverizer to obtain [Masterbatch 1].

[0526] [Preparation of wax dispersion] A container equipped with a stirring rod and a thermometer was charged with 50 parts by mass of paraffin wax (HNP-9, a hydrocarbon wax, melting point 75°C, SP value 8.8, manufactured by Nippon Seiro Co., Ltd.) as a release agent 1 and 450 parts by mass of ethyl acetate. The mixture was heated to 80°C while stirring, maintained at 80°C for 5 hours, and then cooled to 30°C over 1 hour. A bead mill (Ultraviscomill, manufactured by Imex Co., Ltd.) was used to fill the mixture with 80% by volume of zirconia beads with a diameter of 0.5 mm at a liquid feed rate of 1 kg / hr and a disk peripheral speed of 6 m / sec, and dispersed three times to obtain [wax dispersion 1].

[0527] [Preparation of Crystalline Polyester Resin Dispersion] A container equipped with a stirring rod and a thermometer was charged with 50 parts by mass of the [amorphous polyester resin] from Production Example 1 and 450 parts by mass of ethyl acetate, and the mixture was heated to 80°C while stirring. The temperature was maintained at 80°C for 5 hours, and then cooled to 30°C over 1 hour. Dispersion was carried out using a bead mill (Ultraviscomill, manufactured by Imex Co., Ltd.) at a liquid feed rate of 1 kg / hr, a disk peripheral speed of 6 m / sec, 80% by volume filled with 0.5 mm diameter zirconia beads, and 3 passes to obtain [crystalline polyester resin dispersion 1].

[0528] [Preparation of oil phase] Into another container equipped with a thermometer and a stirrer, 78 parts by mass of the [non-crystalline polyester resin] from Production Example 1, 70 parts by mass of [crystalline polyester resin dispersion 1], 25 parts by mass of [wax dispersion 1], and 16 parts by mass of [master batch 1] were placed, and ethyl acetate was added to make the solid concentration 30%, and the mixture was stirred to dissolve thoroughly.

[0529] Next, the mixture was stirred at 8,000 rpm using a TK homomixer (manufactured by Primix Corporation) to uniformly dissolve and disperse the mixture. Furthermore, isophorone diamine (IPDA) was added in an amount such that the molar ratio (NH2 / NCO) of the amino groups of IPDA to the isocyanate groups of the [intermediate polyester] of Production Example 3 was 0.98, and the mixture was stirred at 8,000 rpm for 15 seconds using a TK homomixer. Next, 30 parts by mass of [reactive precursor a] prepared in a 50% ethyl acetate solution was added, and the mixture was stirred at 8,000 rpm for 30 seconds using a TK homomixer to obtain [oil phase 1].

[0530] [Preparation of aqueous phase] In a container equipped with a stirrer and a thermometer, 75 parts by mass of ion-exchanged water, 1 part by mass of sodium carboxymethyl cellulose, 16 parts by mass of a 48.5% aqueous solution of sodium dodecyl diphenyl ether disulfonate (Eleminol (registered trademark) MON-7, manufactured by Sanyo Chemical Industries, Ltd.), and 5 parts by mass of ethyl acetate were mixed and stirred, and 1.2 parts by mass of the solids content of [aqueous dispersion (W0-1)] and an amount equivalent to 1.2 parts by mass of the solids content of [aqueous dispersion (W-1)] were further added to prepare an aqueous phase solution. This was designated [aqueous phase 1].

[0531] [Emulsification and desolvation] 50 parts by mass of [Aqueous Phase 1] was added to a container containing [Oil Phase 1], and the mixture was mixed for 2 minutes at 8,000 rpm using a TK Homomixer, followed by 20 minutes of mixing to obtain [Emulsified Slurry 1]. Next, [Emulsified Slurry 1] was placed in a container equipped with a stirrer and thermometer, and the solvent was removed at 30°C for 8 hours, followed by aging at 45°C for 4 hours to obtain [Dispersed Slurry 1].

[0532] [Washing and drying] 100 parts by mass of [Dispersion Slurry 1] was filtered under reduced pressure, and then the following operations were carried out.

[0533] (1) 100 parts by mass of ion-exchanged water was added to the filter cake, and the mixture was mixed with a TK homomixer (at a rotation speed of 12,000 rpm for 10 minutes) and then filtered. (2) 100 parts by mass of a 10% aqueous solution of sodium hydroxide was added to the filter cake of (1), and the mixture was mixed in a TK homomixer (at a rotation speed of 12,000 rpm for 30 minutes), followed by filtration under reduced pressure. (3) 100 parts by mass of 10% hydrochloric acid was added to the filter cake of (2), and the mixture was mixed in a TK homomixer (at 12,000 rpm for 10 minutes) and then filtered. (4) 300 parts by mass of ion-exchanged water was added to the filter cake of (3), and the mixture was mixed in a TK homomixer (at 12,000 rpm for 10 minutes) and then filtered. (5) The steps (1) to (4) were repeated twice to obtain a filter cake.

[0534] The filtered cake was dried in a circulating air dryer at 45° C. for 48 hours and sieved through a mesh with 75 μm openings to obtain toner base particles 1.

[0535] [External Addition Treatment] 100 parts by mass of the obtained [toner base particles 1] was mixed with 1 part by weight of colloidal silica (Aerosil R972, manufactured by Nippon Aerosil) as an external additive in a sample mill to obtain [toner 1] after external addition treatment.

[0536] Example 2 [Toner base particles 2] were obtained in the same manner as in Example 1, except that in [Preparation of aqueous phase] of Example 1, the amount equivalent to 1.2 parts by mass of the solid content of [aqueous dispersion (W0-1)] and 1.2 parts by mass of the solid content of [aqueous dispersion (W-1)] was changed to an amount equivalent to 0.8 parts by mass of the solid content of [aqueous dispersion (W0-1)] and 1.6 parts by mass of the solid content of [aqueous dispersion (W-1)]. [Toner 2] was produced in the same manner as in Example 1 using the obtained [toner base particles 2].

[0537] Example 3 [Toner base particles 3] were obtained in the same manner as in Example 1, except that in [Preparation of aqueous phase] of Example 1, 1.6 parts by mass of the solid content of [aqueous dispersion (W0-1)] and an amount equivalent to 0.8 parts by mass of the solid content of [aqueous dispersion (W-1)] were changed to an amount equivalent to 2.4 parts by mass of the solid content of [aqueous dispersion (W-2)]. [Toner 3] was produced in the same manner as in Example 1 using the obtained [toner base particles 3].

[0538] Example 4 [Toner base particles 4] were obtained in the same manner as in Example 1, except that in [Preparation of aqueous phase] of Example 1, 1.2 parts by mass of the solid content of [aqueous dispersion (W0-1)] and an amount equivalent to 1.2 parts by mass of the solid content of [aqueous dispersion (W-1)] were changed to 2.4 parts by mass of the solid content of [aqueous dispersion (W-3)]. [Toner base particles 4] were produced in the same manner as in Example 1 using the obtained [toner base particles 4].

[0539] Example 5 [Toner base particles 5] were obtained in the same manner as in Example 1, except that in [Preparation of aqueous phase] of Example 1, 1.2 parts by mass of the solid content of [aqueous dispersion (W0-1)] and an amount equivalent to 1.2 parts by mass of the solid content of [aqueous dispersion (W-1)] were changed to 2.4 parts by mass of the solid content of [aqueous dispersion (W-4)]. [Toner 5] was produced in the same manner as in Example 1 using the obtained [toner base particles 5].

[0540] Example 6 [Toner base particles 6] were obtained in the same manner as in Example 1, except that in [Preparation of aqueous phase] of Example 1, the amount equivalent to 1.6 parts by mass of the solid content of [aqueous dispersion (W0-1)] and 0.8 parts by mass of the solid content of [aqueous dispersion (W-1)] was changed to an amount equivalent to 2.4 parts by mass of the solid content of [polyester particle dispersion]. [Toner 6] was produced in the same manner as in Example 1 using the obtained [toner base particles 6].

[0541] Example 7 [Toner base particles 7] were obtained in the same manner as in Example 1, except that in [Preparation of aqueous phase] of Example 1, 1.6 parts by mass of the solid content of [Aqueous dispersion (W0-1)] and an amount equivalent to 0.8 parts by mass of the solid content of [Aqueous dispersion (W-1)] were changed to an amount equivalent to 2.4 parts by mass of the solid content of [Aqueous dispersion B']. [Toner 7] was produced in the same manner as in Example 1 using the obtained [Toner base particles 7].

[0542] (Comparative Example 1) The same procedure as in Example 1 was repeated except that in the preparation of the aqueous phase in Example 1, the amount of 1.6 parts by mass of the solid content of [aqueous dispersion (W0-1)] and the amount of 0.8 parts by mass of the solid content of [aqueous dispersion (W-1)] were changed to an amount equivalent to 2.4 parts by mass of the solid content of [aqueous dispersion (W-5)]. 8 Using the obtained [toner base particles 8], [toner 8] was produced in the same manner as in Example 1.

[0543] (Comparative Example 2) [Toner base particles 9] were obtained in the same manner as in Example 1, except that in [Preparation of aqueous phase] of Example 1, an amount equivalent to 1.6 parts by mass of the solid content of [aqueous dispersion (W0-1)] and 0.8 parts by mass of the solid content of [aqueous dispersion (W-1)] was changed to an amount equivalent to 1.9 parts by mass of the solid content of [aqueous dispersion (W0-1)] and 0.5 parts by mass of the solid content of [aqueous dispersion (W-2)]. [Toner 9] was produced in the same manner as in Example 1 using the obtained [toner base particles 9].

[0544] (Comparative Example 3) [Toner base particles 10] were obtained in the same manner as in Example 1, except that in [Preparation of aqueous phase] of Example 4, the amount equivalent to 2.4 parts by mass of the solid content of [aqueous dispersion (W-3)] was changed to an amount equivalent to 4.8 parts by mass of the solid content of [aqueous dispersion (W-3)]. [Toner 10] was produced in the same manner as in Example 1 using the obtained [toner base particles 10].

[0545] [Preparation of Carrier] To 100 parts by mass of toluene, 100 parts by mass of silicone resin (organostraight silicone), 5 parts by mass of γ-(2-aminoethyl)aminopropyltrimethoxysilane, and 10 parts by mass of carbon black were added, and the mixture was dispersed for 20 minutes using a homomixer to prepare a resin layer coating liquid.

[0546] Using a fluidized bed coating device, the resin layer coating liquid was applied to the surface of 1,000 parts by mass of spherical magnetite having a volume average particle size of 50 μm, to prepare a carrier.

[0547] [Preparation of Developer] Using a ball mill, 5 parts by mass of each toner and 95 parts by mass of carrier were mixed to prepare each developer.

[0548] Next, the various properties of each of the toners and developers obtained were evaluated as follows, and the results are shown in Table 1.

[0549] [Aggregate Occupancy] The occupancy rate of the aggregates was calculated by the method using the above-mentioned formula (1).

[0550] [Standard deviation of distance between resin particles] The standard deviation of the distance between resin fine particles (organic fine particles) was calculated by the method using the above-mentioned formula (2).

[0551] [Low temperature fixability] The composite resin particles are evenly placed on the paper surface to a density of 0.8 mg / cm2. The powder is placed on the paper surface using a printer with the thermal fixing unit removed. Other methods can be used as long as they can evenly place the powder at the above weight density. The paper is then placed on a pressure roller at a fixing speed (heat roller peripheral speed) of 213 mm / sec and a fixing pressure (pressure roller pressure) of 10 kg / cm2. 2 The temperature at which cold offset occurs (MFT) was measured when the paper was passed through the above conditions.

[0552] The lower the temperature at which cold offset occurs, the better the low-temperature fixability.

[0553] [Cold offset evaluation criteria] A: The minimum fixing temperature is 130°C or less B: Minimum fixing temperature is greater than 130°C and less than or equal to 135°C C: Minimum fixing temperature is greater than 135°C and less than 140°C D: The minimum fixing temperature is higher than 140°C

[0554] [Low adhesion] 160kN / m of each toner 2 The interparticle force (Fp) during compression is measured by measuring the low adhesive force using a powder bed compression / tensile property measuring device (Agrobot (registered trademark), manufactured by Hosokawa Micron Corporation).

[0555] Low adhesion is achieved by filling a certain amount of each toner into a cylindrical cell divided into two parts, upper and lower, under the following conditions, and applying a pressure of 160 kN / m 2 The toner density is calculated from the maximum tensile breaking force when the powder layer is broken by lifting the upper cell after holding it under a pressure of 1000 kJ / cm2, the powder layer height at the time of compression, the inner diameter of the cell, the average particle size of the toner, the true density of the toner, and the amount of the toner.

[0556] Specifically, the toner amount was 8.00 g ± 0.02 g, the ambient temperature was 25 ± 2°C, the humidity was 30 ± 5% RH, the cell inner diameter was 25 mm, the cell temperature was 25°C, the spring wire diameter was 1.0 mm, the compression speed was 0.1 mm / sec, and the compression load was 8 kg (pressure: 160 kN / m 2 ), compression holding time: 60 seconds, tension speed: 0.6 mm / sec, tension sampling start time: 0 seconds, tension sampling time: 25 seconds. The inter-particle force (Fp) calculated by the attached application software was compared with the toner's 160 kN / m 2 The interparticle force (Fp) during compression was evaluated according to the following criteria.

[0557] The measurement was carried out after conditioning the toner at 23° C. and 53% RH for 24 hours.

[0558] [Evaluation criteria] A: Excellent Fp≦180 B: Good 180 <Fp≦250 C: Possible 250 <Fp D: Defective, broken

[0559] [Table 1]

[0560] From the results in Table 1, it is clear that Examples 1 to 7 exhibit excellent performance in both low temperature fixability and low adhesive force.

[0561] On the other hand, in Comparative Example 1, the amount of aggregates on the toner base surface was small, resulting in poor low adhesion, and the amount of free external additives could not be optimized due to the excess aggregates, resulting in poor cleaning performance.

[0562] In Comparative Example 2, the amount of aggregates on the toner base surface was small, and the spacer effect was weak, resulting in poor adhesion. Furthermore, in Comparative Example 2, the standard deviation was too large, resulting in uneven exposure of the toner base, and poor adhesion.

[0563] In Comparative Example 3, the average circularity of the aggregates was too small, resulting in poor low-temperature fixability, and the volume average particle size of the aggregates was too large, resulting in poor low adhesive strength.

[0564] Although the embodiments of the present invention have been described above, the present invention is not limited to the specific embodiments, and various modifications and changes are possible within the scope of the invention described in the claims. [Explanation of symbols]

[0565] 1 Toner base 2, 21, 22 Resin fine particles (organic fine particles) 2´ aggregate 3 Core Resin 4. Shell Resin C1, C2 Center of organic particles M particle size R: Longest diameter of organic fine particles (smallest particles) Longest diameter of R' aggregate 101 latent image carrier 102 Charging device 103 Exposure light 104 Developing device 105 Recording paper 106 Cleaning Department 107 Transfer roller 160(160Y,160C,160M,160K) Sub hopper 180(180Y,180C,180M,180K) Developer 210 Paper feed section P paper 211 Paper cassette 212 Paper feed roller 220 Conveyor 221 Laura 222 Timing roller 223 Paper ejection roller 224 Paper output tray 230 Image creation section 231 (231Y, 231C, 231M, 231K) Photosensitive drum 232 (232Y, 232C, 232M, 232K) Charger 233 Exposure device 233a light source 233b(233bY,233bC,233bM,233bK) Polygon mirror 234 (234Y, 234C, 234M, 234K) Toner Cartridge 236(236Y,236C,236M,236K) Cleaner 240 Transcription Unit 241 Drive roller 242 driven roller 243 Intermediate transfer belt 244 (244Y, 244C, 244M, 244K) Primary transfer roller 245 Secondary opposing roller 246 Secondary transfer roller 250 Fixing unit 251 Fixing belt 252 pressure roller [Prior art documents] [Patent documents]

[0566] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-284881 [Patent Document 2] Japanese Patent Application Publication No. 2019-099809 [Patent Document 3] Japanese Patent Application Publication No. 2019-143128 [Patent Document 4] Japanese Patent Application Laid-Open No. 2009-098194 [Patent Document 5] Patent No. 5879772

Claims

1. A toner having base particles, the base particles contain a crystalline polyester resin, an aggregate of a plurality of organic fine particles adheres to the surface of the base particle; the organic fine particles have a core resin and a shell resin that coats at least a part of the surface of the core resin, the shell resin comprises a styrene-acrylic resin; the major axis of the aggregate is three times or more the major axis of the organic fine particles, the ratio of the aggregates to the surface of the base particle is 16% or more, the average circularity of the aggregates is 0.9 or more, the standard deviation of the distance between adjacent organic fine particles on the surface of the base particle is 500 nm or less; toner.

2. the ratio of the aggregates to the surface of the base particle is 60% or more and 80% or less; The toner according to claim 1 .

3. the average circularity of the aggregates is 0.94 or more and 0.98 or less; The toner according to claim 1 or 2.

4. The volume average particle size of the aggregates is 70 nm or more and 200 nm or less. The toner according to any one of claims 1 to 3.

5. A method for producing the toner according to any one of claims 1 to 4, comprising the steps of: a composite particle forming step of forming composite particles by adhering the organic fine particles to the surfaces of the base particles; a removing step of removing at least a part of the organic fine particles from the composite particles. Toner manufacturing method.

6. the removing step is a step of washing with a basic aqueous solution. The method for producing the toner according to claim 5 .

7. A toner storage unit containing the toner according to any one of claims 1 to 4.

8. An image forming apparatus comprising the toner storage unit of claim 7.

9. An image forming method using the toner according to any one of claims 1 to 4, an electrostatic latent image forming step of forming an electrostatic latent image on an electrostatic latent image carrier; a developing step of developing the electrostatic latent image formed on the electrostatic latent image carrier with toner to form a toner image; a transfer step of transferring the toner image formed on the electrostatic latent image carrier to a medium; a fixing step of fixing the toner image transferred to the medium, Image forming method.

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