JP4957253B2 - Toner for electrostatic image development - Google Patents

Description

  The present invention relates to a toner for developing an electrostatic image, and is particularly excellent in fixability, fluidity, blocking resistance and the like, and provides an electrostatic charge that provides a stable high-quality image even when images are continuously formed. The present invention relates to an image developing toner.

  The electrostatic image developing toner is used in an image forming apparatus such as a printer, a copying machine, or a facsimile. Taking the most common electrophotographic method as an example, after the surface of a photoreceptor, which is a latent image carrier, is uniformly charged, an electrostatic charge image is formed by exposure, and then the electrostatic latent image is developed with a developer. Development is performed to form a toner image corresponding to the electrostatic latent image on the photoreceptor. After the toner image is transferred to a fixing member such as paper, it is fixed on the fixing member by a method such as heating, heating and pressurizing, flashing or solvent to obtain an electrophotographic image.

  As a method for fixing a toner image, a fixing method using heat, for example, a heat roller fixing method, a film fixing method in which a heating body and a fixing body are fixed to each other through a fixing film (or belt), and the like are widely used. It is used.

  In the heat roller fixing method and the film fixing method, the toner image on the fixing member is passed through the surface of the heat roller (fixing roller) or the film (fixing film) while transferring the heat to the toner for fixing. In these fixing methods, the surface of a fixing roller or a fixing film and a fixing body (transfer paper) such as paper are in pressure contact, and the toner image on the non-fixing body is fixed by receiving heat.

  The electrostatic image developing toner is required to have various characteristics in order to smoothly perform the above process. Above all, the toner is quickly fixed on the transfer paper by heating and pressing with a fixing roller or the like, so-called good fixability, and the toner adheres to the fixing roller and contaminates the transfer paper that contacts the fixing roller next time. It is important that the offset phenomenon does not occur and that the obtained image quality does not deteriorate even if printing and copying are continuously performed. In addition to the performance at the time of fixing, the toner is required not to generate fine powder even when subjected to a mechanical impact in the developing device, and to have good fluidity without aggregation. Furthermore, it is also required that no blocking occurs between the production and the supply to the developing device.

  Furthermore, it is desirable that a clear image can be obtained even when the toner is used for a long period of time without contaminating the carrier, the photoreceptor, the developing blade (toner regulating blade), the cleaning blade, etc. . Further, in an image forming apparatus having a high process speed, that is, a high image forming speed, it is desired to secure the toner fixability because the heat transfer time to the toner in the fixing step is short.

  However, it is difficult to produce a toner for developing an electrostatic image that sufficiently satisfies all the required performances. In particular, at the time of fixing, it is extremely difficult to sufficiently satisfy both of them because the toner quickly and strongly adheres to the transfer paper and the offset phenomenon or blocking does not occur.

  In order to meet these demands, various device proposals have been made. For example, with regard to offset, forming the surface of the fixing roller with silicone rubber or fluororesin, or covering the surface of the fixing roller with a thin film of silicone oil to ensure releasability from the toner, etc. Has been done. However, even with these methods, it has been difficult to realize offset resistance that sufficiently satisfies the recent demand for higher image quality. In addition, when trying to improve the apparatus, it has been inevitable that the apparatus becomes complicated, large, and expensive.

  As a method for improving the performance of the toner, it has been proposed to contain a wax inside the toner particles. For example, Patent Document 1 discloses a technique using low molecular weight polypropylene as a component of toner particles, and Patent Document 2 discloses a technique using low molecular weight polyethylene as a component of toner. In addition, Patent Documents 3 to 19 disclose technologies that contain wax.

  However, when wax is included in the toner particles, the toner releasability is improved, but the fluidity is easily deteriorated. This deterioration in fluidity can be improved by adding a fluidity improver such as silica fine powder to the surface of the toner, but conversely, the added silica fine powder is embedded in the toner particles to change the chargeability of the toner. The problem of letting it occur. For this reason, when image formation is performed continuously, the density of the obtained image changes or the uniformity of the image is impaired, making it difficult to stably obtain a good image.

  Although the method of adding wax to the toner particles improves the anti-offset property, the anti-blocking property is insufficient, the fluidity of the toner is lowered, and the anti-contamination property when the toner is used for a long time. Problems such as insufficient are likely to occur. Furthermore, the use of two or more types of wax reduces the compatibility with the binder resin, results in insufficient dispersion of the wax in the binder resin, insufficient blocking resistance, and toner fluidity. Problems such as reduction and poor stain resistance when the toner is used for a long time are likely to occur remarkably.

  As described above, the image quality, fixing performance, anti-offset performance, durability performance, anti-blocking performance, flow performance, anti-contamination performance, etc. required for the toner are simultaneously achieved by the technologies disclosed so far. It was difficult to be satisfied. The performance required of toners varies widely, and for example, improvement in fixing strength tends to cause a decrease in anti-offset performance. Development of toner for developing electrostatic images having excellent performance was expected.

Japanese Patent Publication No.52-003304 Japanese Patent Publication No.57-052574 JP 58-215659 A JP-A-60-217366 JP-A-60-252360 JP-A-60-252361 JP-A-61-138259 JP-A-61-273554 JP 61-094062 A Japanese Patent Laid-Open No. 62-014166 JP-A-1-109359 JP-A-2-079860 JP-A-3-050559 JP-A-4-124676 JP-A-4-299357 JP-A-4-362953 JP-A-5-197192 JP-A-8-050368 JP-A-10-133411

  The present invention solves the above technical difficulties, quickly and strongly fixes on transfer paper, does not cause an offset phenomenon or blocking, has high fluidity, and changes in image density even when continuously copied. It is an object of the present invention to provide a toner for developing an electrostatic image having a low image quality and excellent image quality uniformity and high image quality and high durability. Another object of the present invention is to provide a toner for developing an electrostatic charge image that can obtain a clear image without contaminating a photoreceptor, a developing blade (toner regulating blade), a cleaning blade, and the like even when used continuously.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor is required for the toner as described above by including at least two kinds of waxes having specific DSC curves in the toner particles. As a result, the present inventors have found that the overall performance can be improved and the above-mentioned problems can be solved, and the present invention has been completed.

That is, the present invention relates to an electrostatic charge image developing toner containing at least a binder resin, a colorant, and toner particles containing two or more kinds of waxes, and among the waxes constituting the toner particles. Two types of waxes (wax A and wax B), their respective onset temperatures O (A) and O (B) in the DSC curve measured with a differential scanning calorimeter, and their respective endothermic peak temperatures P (A) and P (B)
O (A) <O (B) and
P (B) ≦ P (A)
Therefore, the present invention provides a toner for developing an electrostatic charge image characterized by the following relationship.

  According to the present invention, when fixing, the toner quickly and strongly adheres to the transfer paper, does not cause an offset phenomenon or blocking, has high fluidity, and can be obtained even if copying continuously. Therefore, it is possible to provide a toner for developing an electrostatic charge image having a high image quality and a high durability with little change in image density. Further, it is possible to provide a toner for developing an electrostatic charge image that can obtain a clear image without contaminating the photoreceptor, the developing blade (toner regulating blade), the cleaning blade, and the like even when continuously used.

  The electrostatic image developing toner of the present invention (hereinafter abbreviated as “toner”) contains toner particles, and the toner particles contain at least a binder resin, a colorant, and two or more kinds of waxes as constituent components. To do.

<Binder resin>
As the binder resin constituting the toner particles in the toner of the present invention, various known resins suitable for the toner particles can be used, and are not particularly limited. For example, styrene resin, polyester resin, epoxy resin, polyurethane resin , Polyvinyl chloride resin, polyethylene resin, polypropylene resin, ionomer resin, silicon resin, rosin-modified maleic acid resin, phenol resin, ketone resin, ethylene-ethyl (meth) acrylate copolymer, polyvinyl butyral resin, etc. Or a mixture thereof. More preferred resins include styrenic resins or polyester resins, and polyester resins are particularly preferred from the standpoints of tribocharging and durability.

  These resins are not limited to being used alone, but two or more of them can be used in combination. The binder resin in the present invention can be used as a non-crosslinked resin, a crosslinked resin, or a mixture thereof. Such a binder resin can be produced by any method such as bulk polymerization, solution polymerization, interfacial polymerization, suspension polymerization, emulsion polymerization, and melt polymerization.

  Styrene resins include polystyrene, polychlorostyrene, poly-α-methylstyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene. -Vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer) Styrene-octyl acrylate copolymer, styrene-phenyl acrylate copolymer, etc.), styrene-acrylic ester-acrylic acid copolymer (styrene-methyl acrylate-acrylic acid copolymer, styrene-ethyl acrylate copolymer) -Acrylic acid copolymer, styrene-butyl acrylate Acrylic acid copolymer, styrene-octyl acrylate-acrylic acid copolymer, styrene-phenyl acrylate-acrylic acid copolymer, etc.), styrene-acrylic acid ester-methacrylic acid copolymer (styrene-methyl acrylate- Methacrylic acid copolymer, styrene-ethyl acrylate-methacrylic acid copolymer, styrene-butyl acrylate-methacrylic acid copolymer, styrene-octyl acrylate-methacrylic acid copolymer, styrene-phenyl acrylate-methacrylic acid Copolymer), styrene-methacrylic acid ester copolymer (styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-octyl methacrylate copolymer). , Styrene-phenyl methacrylate copolymer ), Styrene-methacrylic acid ester-acrylic acid copolymer (styrene-methyl methacrylate-acrylic acid copolymer, styrene-ethyl methacrylate-acrylic acid copolymer, styrene-butyl methacrylate-acrylic acid copolymer) Styrene-octyl methacrylate-acrylic acid copolymer, styrene-phenyl methacrylate-acrylic acid copolymer, etc.), styrene-methacrylic acid ester-methacrylic acid copolymer (styrene-methyl methacrylate-methacrylic acid copolymer) Styrene-ethyl methacrylate-methacrylic acid copolymer, styrene-butyl methacrylate-methacrylic acid copolymer, styrene-octyl methacrylate-methacrylic acid copolymer, styrene-phenyl methacrylate-methacrylic acid copolymer, etc.) , Styrene-α-Chloroacryl Methyl methacrylate copolymer, styrene - acrylonitrile - homopolymers or copolymers containing styrene or styrene derivatives such as acrylic acid ester copolymer. These may be a mixture thereof. In addition, some or all of the acrylic acid and methacrylic acid may be substituted with substituted monocarboxylic acids such as α-chloroacrylic acid and α-bromoacrylic acid, fumaric acid, maleic acid, maleic anhydride, monobutyl maleate and the like. Those substituted with saturated dicarboxylic acids, anhydrides thereof or half esters thereof can also be suitably used.

  Among them, styrene-acrylic acid ester copolymer, styrene-acrylic acid ester-acrylic acid copolymer, styrene-acrylic acid ester-methacrylic acid copolymer, styrene-methacrylic acid ester copolymer, styrene-methacrylic acid ester- It is preferably at least one binder resin selected from the group consisting of acrylic acid copolymers and styrene-methacrylic acid ester-methacrylic acid copolymers. In addition, although the ester group in acrylic acid ester or methacrylic acid ester is not limited, C1-C8 hydrocarbon ester etc. are preferable, such as methyl ester, ethyl ester, butyl ester, octyl ester, and phenyl ester.

  As the polyester resin, those obtained by polycondensation containing a polyhydric alcohol component and a polycarboxylic acid component as main components are preferable. There are no particular limitations on the dihydric alcohol component among the polyhydric alcohol components. For example, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, Diols such as neopentyl glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polytetramethylene glycol; bisphenol A, etherified bisphenols such as hydrogenated bisphenol A, polyoxyethylenated bisphenol A, polyoxypropylenated bisphenol A, and alkylene oxide adducts thereof; and other alcohol monomers Among them, those containing bisphenol A is preferably used.

  In addition, the divalent carboxylic acid component of the polyvalent carboxylic acid component is not particularly limited. For example, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, naphthalene Dicarboxylic acid, diphenic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, malonic acid, n-dodecenyl succinic acid, isododecenyl succinic acid, n-dodecyl succinic acid, isododecyl succinic acid, n- Examples thereof include octenyl succinic acid, isooctenyl succinic acid, n-octyl succinic acid, isooctyl succinic acid, and acid anhydrides of these divalent carboxylic acids. As raw materials for the polyester resin synthesis, in addition to those described above, these lower alkyl esters are also preferably used.

  Furthermore, the polyester resin can contain a trivalent or higher alcohol component and / or a trivalent or higher carboxylic acid component. The trihydric or higher alcohol component is not particularly limited. For example, sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2 , 4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5- And trihydroxymethylbenzene.

  The trivalent or higher carboxylic acid component is not particularly limited. For example, 1,2,4-benzenetricarboxylic acid (trimellitic acid), 1,2,5-benzenetricarboxylic acid, naphthalenetricarboxylic acid, butanetricarboxylic acid, Hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, cyclohexanetricarboxylic acid, tetra (methylenecarboxyl) methane, octanetetracarboxylic acid, pyromellitic acid, embol dimer acid, or these Examples include acid anhydrides and lower alkyl esters.

  These trivalent or higher alcohol components and / or trivalent or higher carboxylic acid components may be contained in an amount of 0.01 to 30 mol%, preferably 0.1 to 5 mol%, based on all monomers constituting the polyester resin. preferable. The inclusion of a trivalent or higher alcohol component and / or a trivalent or higher carboxylic acid component is advantageous for achieving both low temperature fixing required for low energy fixing and durability required for image stability during continuous shooting. It is.

  Furthermore, monofunctional alcohols and monofunctional carboxylic acids such as benzoic acid, salicylic acid, myristic acid, palmitic acid and stearic acid can also be included. Moreover, it can also have the segment which has chains other than ester bonds, such as a urethane bond and an amide bond, in the structure of a polyester resin.

  When the binder resin is a polyester resin, the acid value is preferably 2 to 50 KOHmg / g, and more preferably 3 to 30 KOHmg / g. When the acid value is less than the above range, the dispersibility of the colorant or the charge control agent may decrease, or the image density may decrease when an image is formed using the obtained toner. If the acid value exceeds the above range, the stability of the toner charge amount may be impaired. In particular, the toner's hygroscopicity under high humidity may increase, resulting in image density reduction and density unevenness. The acid value is calculated by dissolving a resin sample in a solvent and titrating with an aqueous potassium hydroxide (KOH) solution according to a conventional method, and is defined as such.

The softening point (hereinafter abbreviated as “Sp”) of the binder resin is usually 150 ° C. or lower, preferably 140 ° C. or lower, for low-temperature fixing. Further, the Sp is preferably 80 ° C. or higher, preferably 100 ° C. or higher from the viewpoint of high temperature offset resistance and durability. Here, Sp is measured in a flow tester (CFT-500, manufactured by Shimadzu Corporation) using a sample of 1.0 g under the conditions of a nozzle of 1 mmφ × 10 mm, a load of 30 kg / cm ² , and a heating rate of 3 ° C./min. The temperature at the midpoint of the strand from the start to the end of the flow is determined and defined as such.

  The glass transition point (hereinafter abbreviated as “Tg”) of the binder resin is usually 80 ° C. or lower, preferably 70 ° C. or lower, for low energy fixing. Further, the Tg is preferably 40 ° C. or higher, preferably 50 ° C. or higher from the viewpoint of blocking resistance. Here, Tg is a differential scanning calorimeter (DSC220 manufactured by Seiko Denshi Kogyo Co., Ltd.). The sample amount is 10 mg, the atmosphere is air, the temperature is increased from 30 ° C. to 110 ° C. at a temperature increase rate of 10 ° C./min, and held for 1 minute. After that, the temperature was lowered to 30 ° C. at 20 ° C./min, held for 3 minutes, and then raised again to 110 ° C. at 10 ° C./min, and a tangent line was drawn at the start of the transition (inflection) of the curve. The temperature is determined as follows.

  The Sp and Tg of the binder resin in the present invention can be adjusted to the above range by adjusting the type of resin, the monomer composition ratio, the molecular weight, and the like, and those in the above range are appropriately selected from commercially available resins. Can be used.

  When the polyester resin is used as the binder resin, the binder resin has a number average molecular weight in gel permeation chromatography (hereinafter abbreviated as “GPC”), preferably 800 or more, more preferably 1000 or more. Yes, preferably 20,000 or less, more preferably 10,000 or less. The binder resin has a weight average molecular weight determined in the same manner of preferably 5000 or more, more preferably 7000 or more, preferably 1 million or less, more preferably 800,000 or less. When the number average molecular weight and the weight average molecular weight of the polyester resin are in the above ranges, it is preferable in terms of toner durability, storage stability, and fixability.

<Colorant>
In the electrostatic charge image developing toner of the present invention, various known colorants suitable for the toner can be used as the colorant constituting the toner particles, and there are no particular limitations. For example, metals such as iron powder and copper powder Powders, metal oxides such as Bengala, inorganic pigments such as carbons typified by carbon black such as furnace black and lamp black, azo series such as benzidine yellow and benzidine orange, quinoline yellow, acid green, and alkali blue Precipitates from dye precipitants, dyes such as rhodamine, magenta, and macalite green tannic acid, acid dyes such as precipitates from phosphomolybdic acid, basic dyes, mordant dyes such as metal salts of hydroxyanthraquinones, phthalocyanine blue Phthalocyanines such as copper phthalocyanine sulfonate, quinacridone red, Examples include organic pigments such as quinacridone and dioxane such as nacridon violet, synthetic dyes such as aniline black, azo dye, naphthoquinone dye, indigo dye, nigrosine dye, phthalocyanine dye, polymethine dye, di- and triallylmethane dye These two or more types can be used in combination.

  When the electrostatic image developing toner of the present invention is used as a full-color toner, an azo pigment (insoluble monoazo, insoluble disazo, condensed azo, etc.), polycyclic pigment (isoindoline, isoindo) is used for yellow. And azo pigments (azo lakes, insoluble monoazos, insoluble disazos, condensed azos, etc.), polycyclic pigments (quinacridone pigments, perylene pigments, etc.). ) And the like, and phthalocyanine pigments, selenium pigments and the like for cyan. The combination of the colorants may be appropriately selected in consideration of the hue and the like. I. Pigment yellow 74, C.I. I. Pigment yellow 93, C.I. I. At least one selected from CI Pigment Yellow 155 is C.I. I. Pigment red 238, C.I. I. Pigment red 269, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 48: 2, C.I. I. At least one selected from CI Pigment Red 122 is C.I. I. Pigment blue 15, C.I. I. At least one selected from CI Pigment Blue 15: 3 is preferable as furnace black carbon as the black colorant.

  The content of the colorant may be an amount sufficient for the obtained toner for developing an electrostatic image to form a visible image by development, and is preferably 1 to 20% by mass in the toner particles, for example. 2 to 15% by mass, more preferably 3 to 10% by mass. When two or more colorants are used in combination, the total amount is preferably within the above range. In addition, it is preferable to use a colorant that contains as little volatile impurities as possible.

In addition, the colorant may have magnetism, and examples of the magnetic colorant include a ferromagnetic material that exhibits ferrimagnetism or ferromagnetism in the vicinity of 0 to 60 ° C., which is a use environment temperature of a printer, a copying machine, and the like. Specifically, for example, magnetite (Fe ₃ O ₄ ), maghemite (γ-Fe ₂ O ₃ ), an intermediate or mixture of magnetite and maghemite, M _x Fe _3-x O ₄ (wherein M is Spinel ferrite such as Mg, Mn, Fe, Co, Ni, Cu, Zn, Cd), hexagonal ferrite such as BaO.6Fe ₂ O ₃ , SrO.6Fe ₂ O ₃ , Y ₃ Fe ₅ O ₁₂ , garnet-type oxide such as _Sm 3 _Fe 5 _{O 12,} rutile-type oxide such as _{CrO 2, Cr, Mn, Fe} , Co, Ni and the like, or around 0 to 60 ° C. of such their ferromagnetic alloys Are exemplified indicates the Oite magnetic, they are not limited to be used alone, may be used alone or in combination. Among these, magnetite, maghematite, or an intermediate between magnetite and maghematite is preferable.

  When the electrostatic charge image developing toner of the present invention is added from the viewpoint of preventing scattering, charging control, etc. while having the characteristics as a non-magnetic toner, the content of the magnetic powder in the toner particles is preferably It is 0.2-10 mass%, More preferably, it is 0.5-8 mass%, Most preferably, it is 1-5 mass%. Further, when used as a magnetic toner, the content of the magnetic powder in the toner particles is preferably 15% by mass or more, particularly preferably 20% by mass or more, and the upper limit is preferably 70% by mass or less, and 60% by mass or less. Is particularly preferred. If the content of the magnetic powder is less than the above range, the magnetic force required for the magnetic toner may not be obtained, and if it exceeds the above range, it may cause poor fixing properties.

  The number average particle diameter of the magnetic powder is preferably 0.5 μm or less, and particularly preferably particles having a number average particle diameter of 0.3 μm or less. Since the magnetic powder having such a particle size is easily dispersed uniformly in the binder resin and is not easily exposed on the surface of the toner particles, the surface of the photoconductor such as an organic photoconductor is hardly damaged and the chargeability tends to be stable. The number average particle diameter of the magnetic powder was selected by randomly selecting about 300 magnetic particles in a photograph obtained by photographing a thin slice of toner at a magnification of 20,000 using a transmission electron microscope, and the horizontal Feret diameter. Is calculated. When the particle size of the magnetic powder does not change between the raw material and the toner particles as the product, the particle size of the magnetic powder as the raw material may be measured.

  When imparting conductivity to the toner for developing an electrostatic charge image of the present invention, it is preferable to blend conductive carbon black as the colorant component and other conductive substances. The content of the conductive material is preferably about 0.05 to 5% by mass in the toner particles.

  The toner for developing an electrostatic charge image of the present invention may contain a charge control agent in order to impart charge amount and charge stability. As the charge control agent, conventionally known compounds are used. For example, as the positive charge control agent, nigrosine dyes, quaternary ammonium salts, triaminotriphenylmethane compounds, imidazole compounds, polyamine resins, etc. As the negative charge control agent, azo complex compound dyes containing atoms such as Cr, Co, Al, Fe, B, salicylic acid or alkylsalicylic acid complex compounds, curixarene compounds, metal salts or metal complexes of benzylic acid, Examples include amide compounds, phenol compounds, naphthol compounds, phenol amide compounds, and hydroxynaphthalene compounds such as 4,4′-methylenebis [2- [N- (4-chlorophenyl) amide] -3-hydroxynaphthalene]. For full-color toners, it is necessary to select a color tone of the charge control agent that is colorless or light in order to avoid a color tone failure as a toner. It is preferably a quaternary ammonium salt compound or an imidazole compound. As the negative charge control agent, salicylic acid or alkylsalicylic acid complex compounds containing atoms such as Cr, Co, Al, Fe, B, Zn, etc., curlyx allene Preferably it is a compound. Moreover, these mixtures may be sufficient. When the charge control agent is contained, the content is preferably from 0.01 to 10% by mass, particularly preferably from 0.1 to 5% by mass, based on the whole toner particles. The charge control agent is usually internally added to the toner particles, but can be externally added to the surface of the toner particles.

  In the present invention, two kinds of waxes having a specific relationship are included in the toner particles, thereby improving the toner fixing performance, offset resistance performance, durability performance, anti-blocking performance, flow performance, anti-contamination performance, etc. , Achieve high image quality. It is extremely difficult to improve the performance of the toner without impairing the specific performance, for example, the above-mentioned performance required for the toner is contrary to the fixing performance and the anti-blocking performance. In the present invention, focusing on the fact that these performances are directly or indirectly related to the thermal properties of the toner particles, the wax that is the most sensitive component to heat among the toner constituent components is specified. In this manner, an excellent performance toner that is well-balanced in all the above performances was realized.

  The toner particles in the toner of the present invention contain two or more kinds of waxes as constituent components. Of the two or more types of waxes, it is essential that the following two conditions are satisfied for certain two types of waxes (the two types of waxes are referred to as wax A and wax B). That is, the respective onset temperatures O (A) and O (B) and the respective endothermic peak temperatures P (A) and P (B) in the DSC curve measured with the differential scanning calorimeter are O (A). <O (B) and P (B) ≦ P (A) are essential. When three or more types of waxes are contained as a constituent component, any two types of waxes may satisfy the above relationship.

  The measurement with a differential scanning calorimeter for wax is performed according to ASTM D3418-8, and is performed using a differential scanning calorimeter DSC220U (product of Seiko Denshi Kogyo Co., Ltd.). The temperature correction of the device detection unit uses the melting points of indium and zinc, and the correction of heat uses the heat of fusion of indium. A wax sample to be measured, 10 mg, is weighed precisely, placed in an aluminum pan, and first heated from 25 ° C. to 150 ° C. at a rate of 10 ° C./min. After holding at 150 ° C. for 3 minutes, cooling from 150 ° C. to 0 ° C. at 10 ° C./minute to erase the previous history, holding at 0 ° C. for 3 minutes, and then starting from 0 ° C. at a rate of temperature increase of 10 ° C./minute The temperature is raised to 150 ° C. to obtain a DSC curve.

  And as shown in FIG. 1, let the temperature in the maximum peak point in the obtained DSC curve be endothermic peak temperature (P). Further, as shown in FIG. 1 and FIG. 2, the onset temperature (O) is tangent to the DSC curve at the point where the absolute value of the differential value of the DSC curve from the start of endotherm to the endothermic peak in the DSC curve becomes maximum. To obtain the temperature at the intersection of the tangent and the baseline. Here, as shown in FIG. 1, the baseline is obtained by drawing the DSC curve parallel to the temperature axis (horizontal axis) in a substantially flat portion without the influence of the endothermic peak. Further, since the wax A and the wax B are separately measured by the differential scanning calorimeter, the baselines are drawn independently of each other.

  When a wax has two or more maximum peaks, the endothermic peak temperature (P) uses the highest endothermic peak, and the onset temperature (O) is determined with the lowest endothermic temperature. Adopt a peak. That is, a tangent line is drawn on the DSC curve at the point where the absolute value of the differential value of the DSC curve between the endothermic peak and the endothermic peak at the lowest endothermic peak reaches the maximum, and the intersection of the tangent line and the baseline is determined by the wax. On-set temperature (O).

  In the present invention, the onset temperature (O (A), O (B)) in a DSC curve measured with a differential scanning calorimeter of two types of waxes (wax A, wax B) contained in the toner particles, The endothermic peak temperatures (P (A), P (B)) are O (A) <O (B) and PP (B) ≦ (A), that is, the two contained in the toner particles. Of the types of waxes, the endothermic peak temperature of the wax having the lower onset temperature is higher than the endothermic peak temperature of the other wax.

  Of the two types of wax contained in the toner particles, by mixing the wax A having a low endothermic peak temperature with the wax A having a lower onset temperature than the wax B, the offset resistance and the blocking resistance are not deteriorated. The viscosity lowering temperature as toner particles is shifted to the low temperature side, and good fixability can be obtained. In this case, when wax A having an endothermic peak temperature lower than the endothermic peak temperature of wax B is selected, that is, O (A) <O (B) and P (A) <P (B) In the case of the relationship, there is a case where the offset resistance and the blocking resistance are deteriorated. When the endothermic peak temperature of the wax A is the same as or higher than the endothermic peak temperature of the wax B, such a problem can be avoided.

  Further, when the wax A is an ester wax, a more excellent fixing effect is exhibited in terms of compatibility with the binder resin. Furthermore, when the binder resin is polyester, the compatibility is further increased. In addition, a further excellent fixing effect is exhibited.

  The onset temperature O (A) is preferably 40 ° C. or higher, particularly preferably 45 ° C. or higher. The upper limit is preferably 70 ° C. or lower, and particularly preferably 65 ° C. or lower. When it is in the above range, blocking resistance and fixability are particularly excellent.

  On the other hand, the onset temperature O (B) is preferably 45 ° C. or higher, particularly preferably 50 ° C. or higher, and the upper limit is preferably 70 ° C. or lower, particularly preferably 65 ° C. or lower. When the content is within the above range, a toner having particularly excellent blocking resistance and fixing ability can be provided.

  The difference between the onset temperatures O (A) and O (B) is preferably larger in terms of the balance between offset resistance, blocking resistance, and fixability.

  The endothermic peak temperature P (A) is not particularly limited, but is preferably 60 ° C. or higher and particularly preferably 70 ° C. or higher in terms of blocking resistance, durability, stain resistance, and the like. Further, the endothermic peak temperature P (B) is not particularly limited, but is preferably 60 ° C. or higher and particularly preferably 65 ° C. or higher in terms of blocking resistance, durability, contamination resistance, and the like. Moreover, it is preferable that both endothermic peak temperatures P (A) and P (B) are 60 ° C. or higher. When one or both of P (A) and P (B) is less than 60 ° C., sufficient blocking resistance, durability, stain resistance and the like may not be obtained.

  The upper limit of the endothermic peak temperature P (A) is preferably 120 ° C. or less, and particularly preferably 110 ° C. or less from the viewpoint of fixability. In addition, the upper limit of the endothermic peak temperature P (B) is preferably 110 ° C. or less, and particularly preferably 100 ° C. or less in terms of fixability. Further, it is preferable that the difference between P (A) and P (B) is 20 ° C. or less because good fixability can be obtained. Particularly preferably, the difference is 15 ° C. or less. On the other hand, the lower limit of the difference between P (A) and P (B) is not particularly limited as long as P (B) ≦ P (A) is satisfied, but it is 0 in terms of blocking resistance and fixability. It is preferably higher than 0 ° C, particularly preferably 3 ° C or higher.

  Further, in a DSC curve measured with a differential scanning calorimeter of two kinds of waxes (constituting “wax A” and “wax B”, respectively) among the waxes that are constituents of the toner particles, The endothermic start temperature of the wax A (hereinafter abbreviated as “endothermic start temperature S (A)”) is lower than the endothermic start temperature of the wax B (hereinafter abbreviated as “endothermic start temperature S (B)”). It is preferable in that the viscosity lowering temperature as the toner particles can be shifted to the low temperature side and good fixability can be obtained without deteriorating the offset resistance and blocking resistance.

  The two types of wax A and wax B having the above-mentioned relationships are not particularly limited with respect to their chemical structures. For example, olefinic waxes such as low molecular weight polyethylene, low molecular weight polypropylene, and copolymerized polyethylene; paraffin wax; Ester waxes having long chain aliphatic groups such as behenyl behenate, montanate ester, stearyl stearate; plant waxes such as hydrogenated castor oil and carnauba wax; ketones having long chain alkyl groups such as distearyl ketone; alkyl Group-containing silicone; higher fatty acid such as stearic acid; long-chain aliphatic alcohol such as eicosanol; carboxylic acid ester or carboxylic acid partial ester of polyhydric alcohol obtained from polyhydric alcohol such as glycerin and pentaerythritol and long-chain fatty acid ; Maleic acid amides, higher fatty acid amides such as stearic acid amide; low molecular weight polyester.

  Particularly preferred as the wax A is behenic acid such as behenyl behenate in that the viscosity lowering temperature can be shifted to a low temperature side even with a small amount, and sufficient release properties can be imparted, and it has compatibility with the polyester resin. Examples include esters; montanic acid esters; stearic acid esters such as stearyl stearate; and ester waxes such as carnauba wax.

  Particularly preferred as the wax B is behenic acid such as behenyl behenate in that it can give sufficient release properties by shifting the viscosity lowering temperature to a low temperature even with a small amount, and has compatibility with a polyester resin. Examples include esters; montanic acid esters; stearic acid esters such as stearyl stearate; and ester waxes such as carnauba wax.

  In the present invention, it is necessary that two types of waxes (wax A and wax B) among the waxes that are constituents of the toner particles satisfy the above requirements. The ratio of the total amount of the “two kinds of waxes (wax A and wax B)” to the total wax in the toner particles is preferably 60% by mass or more, more preferably 80% by mass or more, and 100% by mass, It is particularly preferred that all of the waxes in the toner particles are wax A and wax B.

  The total wax content in the toner particles (that is, the total content of two or more kinds of waxes) is not particularly limited, but is preferably 8 parts by weight or less, more preferably 5 parts by weight or less, based on 100 parts by weight of the toner particles. preferable. When the wax in the toner particles is higher than these contents, sufficient performance may not be obtained in terms of fluidity and stain resistance. On the other hand, the lower limit of the total wax content in the toner particles is not particularly limited, but is preferably 1 part by weight or more, particularly preferably 2 parts by weight or more with respect to 100 parts by weight of the toner particles. When the wax in the toner particles is less than these contents, sufficient performance in fixability may not be obtained.

  The content of each of wax A and wax B in 100 parts by weight of toner particles is preferably 0.5 to 4 parts by weight, particularly preferably 0.8 to 2.5 parts by weight for wax A. . Moreover, about wax B, 0.5 weight part-7.5 weight part is preferable, and 1.5 weight part-4.5 weight part is especially preferable. Furthermore, by fixing the content of the wax having the lower onset temperature (wax A) in the toner particles to be lower than the content of the wax having the higher onset temperature (wax B), the fixability and resistance can be improved. A toner having an excellent balance with blocking properties can be obtained. Particularly preferably, the content of wax A is in the range of 0.2 to 0.9 times the content of wax B, and more preferably in the range of 0.3 to 0.8 times.

  In general, it has been considered that it is not preferable to produce toner particles using two or more types of wax because the dispersibility of the wax in the binder resin tends to deteriorate. However, in the present invention, the two types of wax satisfy the above-mentioned specific relationship, so that the problem of deterioration in dispersibility does not occur. Instead, the wax is simply a wax as described in the above “problem to be solved by the invention”. When two or more types are used, an effect exceeding the expected effect is achieved.

  The characteristic of wax A is that its absorption peak temperature (P) is higher than that of wax B and its onset temperature (O) is lower than that of wax B in its DSC curve. That is, the DSC curve of wax A shows that the absorption peak is relatively broad. The wax having such properties exhibits a DSC curve in which endotherm can be observed in a low temperature range. In general, it is considered that such a wax does not have excellent blocking resistance, fluidity and the like since the melting of the wax starts from a low temperature range.

  On the other hand, the characteristic of wax B is that its absorption peak temperature (P) is lower than that of wax A and its onset temperature (O) is higher than that of wax A in its DSC curve. That is, the DSC curve of wax B shows that the endothermic peak is relatively sharp. Waxes exhibiting such properties are known as waxes having excellent fixability since the wax melts at a specific temperature.

  Thus, conventionally, it is difficult to use only the wax having the property of wax A because it is expected to impair the toner performance, and the wax having the property of wax B has been preferably used. However, when wax B is used alone, there is a problem that the onset temperature is high and the fixing strength is insufficient to obtain low temperature fixability. In the present invention, the problem of fixing when the wax B is unexpectedly used alone can be solved by using the wax B, which has been considered unsuitable as a wax for toner, in combination with the wax B as described above. It was.

  In the present invention, the method for producing toner particles is not particularly limited, but is preferably produced by a kneading and pulverizing method. In this case, it can be produced according to a conventionally known method. That is, usually, first, a binder resin, a colorant, a wax, and a charge control agent and other components added as necessary (hereinafter, these may be collectively referred to as “raw materials”) are mixed in a mixer. Disperse and mix uniformly. As the apparatus at this time, a gravity drop type mixer such as a V blender or a ball mill, a high speed fluid mixer such as a Henschel mixer (made by Mitsui Miike Chemical Co., Ltd.), a super mixer (made by Kawata Co., etc.), or the like is used. Next, the mixture is melt-kneaded with two or three rolls, a Banbury mixer, a CM mixer, a closed kneader, a single or twin screw extruder, etc., and after cooling, coarsely crushed with a crusher, hammer mill, cutter mill, etc. Finely pulverize with a jet mill, high-speed rotor rotary mill, etc., and classify with an air classifier (eg, inertia class elbow jet, centrifugal class microplex, DS separator, etc.) Get the diameter range. Usually, a particle size in the range of 3 to 12 μm, preferably 3 to 10 μm is obtained.

  The raw materials may be dispersed and blended at the same time, but may be dispersed and blended in multiple stages by changing the blending timing of some raw materials. Furthermore, you may add a part of raw materials in the process in the middle of melt-kneading. Two or more kinds of waxes can be used as a raw material for dispersion and mixing, but two or more kinds of waxes or wax A and wax B may be mixed in advance and then used for dispersion and mixing, or as a molten mixture or You may use for a dispersive mixing as a masterbatch.

  In addition to the above kneading and pulverizing method, any of wet methods such as a polymerization method (suspension polymerization method and emulsion polymerization aggregation method) and a solvent precipitation method (chemical pulverization method) can be used as a method for producing toner particles. However, it is preferable to produce by a kneading and pulverizing method because the effect of the present invention is remarkable. This is because the wax composition is appropriately dissolved and dispersed in the toner composition in the dispersion mixing step and the melt kneading step of the kneading and pulverizing method, and the wax component is appropriately exposed on the toner particle surface in the pulverizing step. This is because the effect is likely to appear.

  The toner of the present invention has excellent stain resistance, and when used as a two-component developer, the carrier is less contaminated and enables stable development of the two-component developer. When used as the above, the above-mentioned effects of the present invention are more effectively exhibited.

  When the toner of the present invention is used as a two-component developer, a conventional carrier such as iron powder, ferrite powder or magnetite powder having a particle size of about 20 to 200 μm may be used as the magnetic carrier. These are also preferably used after being coated with a silicone resin, an acrylic resin, a fluorine resin, a styrene resin or the like.

  The toner for developing an electrostatic charge image according to the present invention can be used as a non-magnetic one-component developer or a magnetic one-component developer. In the case of a magnetic one-component developer, the magnetic powder may be ferrite, magnetite, an alloy of ferromagnetic metal such as iron, cobalt, nickel, or the like. The magnetic powder is preferably used in an amount of 20 to 70 parts by weight per 100 parts by weight of the binder resin.

  The electrostatic image developing toner of the present invention can be obtained by externally adding an external additive to the toner particles as necessary. The external additive can be appropriately selected from various inorganic or organic fine particles and is not particularly limited. For example, metal oxides such as silicon oxide, titanium oxide, aluminum oxide, magnesium oxide, and zinc oxide are used. Alternatively, those obtained by subjecting them to surface treatment are used.

  The toner for developing an electrostatic charge image of the present invention is particularly suitable for use in a thermal fixing system because it has excellent fixability and offset resistance. In the heat fixing method, the fixing property by heat is good, the toner adheres to the fixing roller and contaminates the transfer paper that contacts the fixing roller next time, so-called offset phenomenon does not occur, and continuous printing and copying are performed. Although it is required that the obtained image quality does not deteriorate even if it is performed, the electrostatic image developing toner of the present invention meets these required performances and is particularly suitable for use in a thermal fixing system.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present description is not limited to the following examples unless it exceeds the gist. In the following examples and comparative examples, “parts” simply means “parts by weight”.

The test method and evaluation method were as follows.
<Evaluation method of blocking resistance>
10 g of toner is placed in a SUS cylinder having an inner diameter of 28 mmφ (radius: 1.4 cm), a 20 g weight is placed thereon, 48 g at 50 ° C. for 48 hours, 3.2 g / cm ² (= 20 g / (π × 1.4 (cm ² ) The load of ² )) was applied. Thereafter, the SUS tube was removed, and the blocking resistance was evaluated by confirming the collapse of the applied load.

<Method for evaluating fixability and hot offset resistance>
In Example 1 and Comparative Example 1, an image was formed by the method described in Example 1 below, and the fixability and hot offset resistance were evaluated by the method described in Example 1. In Example 2, Comparative Example 2 and Comparative Example 3, images were formed by the method described in Example 2 below, and the fixability and hot offset resistance were evaluated by the method described in Example 2.

Example 1
The following components were mixed, kneaded, pulverized, and classified to obtain negatively charged black toner particles having an average particle diameter of 8 μm.

<Components of toner particles>
60 parts of polyester resin A (crosslinked resin having a peak molecular weight of 5200 by GPC and Sp of 132 ° C. by a flow tester)
40 parts of polyester resin B (non-crosslinked resin having a peak molecular weight of 5200 by GPC and Sp of 101 ° C. by a flow tester)
Metal-containing azo dye-based charge control agent 1 part (T-77, manufactured by Hodogaya Chemical Co., Ltd.)
7 parts of carbon black (Regal 330R, manufactured by Cabot)
1 part of ester wax-α (onset temperature in DSC curve is 56.1 ° C., endothermic peak temperature is 80.2 ° C.)
Ester wax-β 2.5 parts (onset temperature in DSC curve is 66.3 ° C., endothermic peak temperature is 76.3 ° C.)

  The DSC curve of ester wax-α is shown in FIG. 3, and the DSC curve of ester wax-β is shown in FIG.

  To 100 parts of the toner particles, 0.5 part of hydrophobized silicon dioxide (trade name Aerosil NAX50, manufactured by Nippon Aerosil Co., Ltd.) and 0.3 part of hydrophobized silicon dioxide (trade name Aerosil R972, manufactured by Nippon Aerosil Co., Ltd.) The toner was mixed with a Henschel mixer and externally added to obtain a toner for developing an electrostatic image. The toner had a softening point of 115.0 ° C. and a Tg of 59.6 ° C.

  When the blocking resistance of the obtained toner was evaluated, it was good.

  4 parts of the obtained toner and 96 parts of a ferrite carrier coated with a silicone resin and having an average particle size of 80 μm were mixed and stirred to prepare a negatively chargeable two-component developer.

Using this developer, and using the obtained toner as a replenishing toner, ^two unfixed halftone images of 3 cm square were printed on a 90 g / m ² thick paper using a commercially available digital multifunction peripheral. Obtained.

  Using this unfixed image, a fixing test was carried out using an external fixing machine composed of a 60 mm-mm fluororesin fixing roller and a silicone pressure roller, which was modified from a commercially available copying machine and equipped with a temperature / speed controller. .

  The fixing test was performed at a process speed of 360 mm / second, after fixing at a fixing temperature of 160 ° C. and 170 ° C., respectively, and using a jig with gauze (Bencot M-3, manufactured by Asahi Kasei Co.) attached to the bottom surface of a weight of 630 g. The image density ratio before and after rubbing 5 times in one direction was calculated as a residual residual rate (%).

  As a result of the fixing test, the residual rate of the image fixed at 160 ° C. was 97.7%, and the residual rate of the image fixed at 170 ° C. was 100%. Moreover, it was excellent in hot offset resistance without offsetting to 220 ° C.

Comparative Example 1
Instead of the ester wax-α used in Example 1, an ester wax-γ (onset temperature in DSC curve is 71.3 ° C., endothermic peak temperature is 87.0 ° C.) is used. A toner and a developer were prepared in exactly the same manner as in Example 1. The DSC curve of the ester wax-γ is shown in FIG. The toner had a softening point of 113.7 ° C. and a Tg of 61.0 ° C.

  As a result of performing the fixing test in the same manner as in Example 1, the residual rate of the image fixed at 160 ° C. was 93.5%, and the residual rate of the image fixed at 170 ° C. was 97.0%, which was 160 ° C. It was found that the fixing temperature was inferior to the level of Example 1 at any fixing temperature of 170 ° C.

Example 2
The following components were mixed, kneaded, pulverized, and classified to obtain negatively chargeable magenta toner particles having an average particle diameter of 8 μm.

<Components of toner particles>
40 parts of polyester resin C (cross-linked resin having a peak molecular weight of 8200 by GPC and Sp of 156 ° C. by a flow tester)
60 parts of polyester resin D (non-crosslinked resin having a peak molecular weight of 4800 by GPC and Sp of 97 ° C. by a flow tester)
Boron compound charge control agent 1 part (LR147, manufactured by Nippon Carlit Co., Ltd.)
8 parts of magenta masterbatch (Carmine 6B pigment 40% by mass / Polyester resin D 60% by mass, manufactured by Sanyo Dye)
1 part of ester wax-α (onset temperature in DSC curve is 56.1 ° C., endothermic peak temperature is 80.2 ° C.)
Ester wax-β 2.5 parts (onset temperature in DSC curve is 66.3 ° C., endothermic peak temperature is 76.3 ° C.)

  To 100 parts of the toner particles, 0.5 part of hydrophobized silicon dioxide (trade name Aerosil NAX50, manufactured by Nippon Aerosil Co., Ltd.) and 0.3 part of hydrophobized silicon dioxide (trade name Aerosil R972, manufactured by Nippon Aerosil Co., Ltd.) The toner was mixed with a Henschel mixer and externally added to obtain a toner for developing an electrostatic image. This toner had a softening point of 115.8 ° C. and a Tg of 62.7 ° C.

  When the blocking resistance of the obtained toner was evaluated, it was good.

  4 parts of the obtained toner and 96 parts of a ferrite carrier coated with a silicone resin and having an average particle size of 80 μm were mixed and stirred to prepare a negatively chargeable two-component developer.

Using this developer and using the obtained toner as a replenishing toner, several unfixed solid images of 3 cm square were obtained on 65 g / m ² paper using a commercially available digital multi-function machine. . Similarly, several unfixed solid images of 3 cm square were obtained on 100 g / m ² paper.

  Using this unfixed image, a fixing test was carried out using an external fixing machine composed of a 40φ mm PFA sleeve-covered fixing roller and the same pressure roller, which was modified from a commercially available copying machine and equipped with a temperature / speed controller. .

In the fixing test, a process speed of 90 mm / s was applied to an image printed at 65 g / cm ² , and the occurrence of hot offset was confirmed in increments of 10 ° C. from a fixing temperature of 160 ° C. to 200 ° C. On the other hand, for an image printed at 100 g / cm ² , the process speed is 120 mm / s, and after fixing in steps of 10 ° C. from 160 ° C. to 200 ° C., gauze (Bencot M-3, Asahi Kasei Co., Ltd.) Using a jig attached, a fixing image was confirmed by visually confirming the drop of the image after rubbing the solid image five times in one direction.

  As a result, the image was not peeled off even at 160 ° C., and the fixing strength was good. Further, there was no problem with hot offset up to 190 ° C., and a blister with a slightly rough image surface was generated at 200 ° C., and the hot offset resistance was good.

Comparative Example 2
A toner and a developer were prepared in the same manner as in Example 2 except that the same ester wax-γ as in Comparative Example 1 was used instead of the ester wax-α used in Example 2. Example 2 The same fixing test was conducted.

  As a result, peeling of the image was confirmed in fixing at 160 ° C.

Comparative Example 3
Toner and development in the same manner as in Example 2 except that 3.5 parts of ester wax-α was blended instead of the blend of ester wax-α and ester wax-β used in Example 2. The same fixing test as in Example 2 was performed.

  As a result, it was confirmed that the image was peeled off at 160 ° C. fixing. Further, with respect to hot offset resistance, blisters were generated at 190 ° C., and clearly decreased as compared with Example 2. In addition, the blocking resistance was slightly agglomerated.

  The toner for developing an electrostatic charge image of the present invention is excellent in fixability, fluidity, and blocking resistance, and can stably form a high-quality image even when images are continuously formed. Is to provide.

The definitions of onset temperature (O), endothermic peak temperature (P), and endothermic start temperature (S) in the DSC curve are shown, and onset temperatures O (A), O (B), endothermic peak temperature P (A ), An example of the relationship of P (B). It is an enlarged view of a portion showing onset temperatures O (A) and O (B) in the DSC curve. It is a DSC curve of ester wax-α. It is a DSC curve of ester wax-β. It is a DSC curve of ester wax-γ.

Claims (11)

An electrostatic charge image developing toner containing at least a binder resin, a colorant, and toner particles containing two or more kinds of waxes, and two kinds of waxes among the waxes constituting the toner particles ( The respective onset temperatures O (A) and O (B) and the respective endothermic peak temperatures P (A) and P (B) in the DSC curve of wax A and wax B) measured with a differential scanning calorimeter But,
O (A) <O (B) and
P (B) ≦ P (A)
An electrostatic charge image developing toner characterized by the following relationship:   The electrostatic image developing toner according to claim 1, wherein the onset temperature O (A) is 40 ° C. or higher and 70 ° C. or lower.   The electrostatic image developing toner according to claim 1, wherein both endothermic peak temperatures P (A) and P (B) are 60 ° C. or higher.   The electrostatic image developing toner according to claim 1, wherein a difference between the endothermic peak temperature P (A) and the endothermic peak temperature P (B) is 20 ° C. or less.   5. The electrostatic charge image developing device according to claim 1, wherein the total content of the two or more types of wax in the toner particles is 8 parts by weight or less based on 100 parts by weight of the toner particles. toner.   6. The electrostatic image developing toner according to claim 1, wherein the content of the wax A in the toner particles is smaller than the content of the wax B.   7. The electrostatic image developing toner according to claim 1, wherein the wax A is an ester wax.   The toner for developing an electrostatic charge image according to any one of claims 1 to 7, wherein the binder resin is a polyester resin.   9. The electrostatic image developing toner according to claim 1, wherein the toner particles are produced by a kneading and pulverizing method.   The electrostatic image developing toner according to claim 1, wherein the electrostatic image developing toner is used in a thermal fixing system.   11. The electrostatic image developing toner according to claim 1, wherein the electrostatic image developing toner is a two-component developer toner.

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