Toner

Abstract

To provide a toner which offers superior fixability and is capable of minimizing fixing film stains and adhesion of ejected sheets.SOLUTION: A toner provided herein comprises toner particles, each comprising a core particle containing a binder resin and diester wax, and a shell formed to cover a surface of the core particle, and satisfies the following expressions (1) and (2): Sp≤0.40 ...(1), 16.00≤Wp-Sp≤20.00 ...(2), where Sp represents a partition coefficient of the shell and Wp represents a partition coefficient of the diester wax.SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to a toner used in an image forming apparatus such as a copying machine, a printer, and a facsimile apparatus using an electrophotographic method or an electrostatic recording method.

Background Art

[0002] Conventionally, many methods are known as electrophotographic methods. Generally, first, using a photoconductive substance, an electrical latent image is formed on a photoreceptor by various means, and then the electrical latent image is developed using toner to form a visible image. Then, after transferring the toner image to a transfer material such as paper, the toner image is fixed on the transfer material by heat, pressure, etc. to obtain a fixed image. The toner remaining on the photoreceptor without being transferred to the transfer material during transfer is cleaned by various methods. In laser beam printers and copying machines, in recent years, there has been a demand for lower power consumption and further higher image quality. In order to meet the requirement of lower power consumption, a toner that melts quickly at a lower temperature, that is, a toner having excellent low-temperature fixability, is desired.

[0003] In addition, printers are often used by multiple users to output simultaneously, and the printed materials output may be stacked and left unattended for a while. It is desired to have a toner that does not cause paper sticking, that is, the printed material immediately after printing has a high temperature and the printed toner adheres to the paper. In order to obtain a toner having excellent low-temperature fixability, studies have been made on using wax in the toner. Wax is added for the purpose of mold release and imparting plasticity to the binder resin. Among them, various studies have been conducted on ester wax as a wax having excellent plasticity. For example, in Patent Document 1, a toner using a diester compound as a wax and having improved low-temperature fixability, hot offset resistance, and heat storage stability has been proposed. Also, in Patent Document 2, a technique has been proposed in which the shell layer of the toner is made of a thermosetting resin to achieve both low-temperature fixability and stress resistance.

Prior Art Documents

Patent Documents

[0004] [Patent Document 1] International Publication No. 2013 / 047296 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-022237 [Summary of the Invention] [Problems to be Solved by the Invention]

[0005] However, in Patent Document 1, although it is effective for improving low-temperature fixability, it has been found that there is room for improvement in the adhesiveness to the fixing film and paper jamming during paper ejection. Since the diester compound has high compatibility with the binder resin while having a tendency to have low phase separability from the resin, the releasability from the fixing film tends to decrease. Also, since the releasability from paper also decreases at the same time, the above-described paper jamming also tends to occur easily. Further, in Patent Document 2, although it is effective for durability and low-temperature fixability, there has been no discussion regarding fixing film contamination and paper jamming, and there is room for improvement. As described above, there is still room for improvement in achieving both excellent fixability and suppression of fixing film contamination and paper jamming. The present disclosure provides a toner having excellent fixability and capable of suppressing fixing film contamination and paper jamming. [Means for Solving the Problems]

[0006] The present disclosure relates to a toner having toner particles including core particles containing a binder resin and a diester wax, and a shell formed on the surface of the core particles, relating to a toner that satisfies the following formulas (1) and (2) when the partition coefficient of the shell is Sp and the partition coefficient of the diester wax is Wp. Sp ≦ 0.40 ··· (1) 16.00 ≦ Wp - Sp ≦ 20.00 ··· (2) [Effects of the Invention]

[0007] According to the present disclosure, it is possible to provide a toner having excellent fixing property and capable of suppressing fixing film contamination and paper sticking during paper discharge.

Brief Description of the Drawings

[0008]

Figure 1

Mode for Carrying Out the Invention

[0009] The description of "XX or more and YY or less" or "XX to YY" representing a numerical range means a numerical range including the lower limit and the upper limit which are the endpoints, unless otherwise specified. When numerical ranges are described stepwise, the upper limit and the lower limit of each numerical range can be arbitrarily combined.

[0010] The present inventors have intensively studied a toner having excellent fixing property and capable of suppressing fixing film contamination and paper sticking during paper discharge. First, the present inventors considered the fixing film contamination, but went back to the heat fixing process itself for examination. In the heat fixing process, the unfixed toner on the paper is melted and spreads by receiving heat and pressure. Also, in some cases, a crystalline material such as wax oozes out on the surface of the toner particles and the toners are bonded together. In order to improve the fixing property, it is important to quickly and firmly connect the paper and the toner, and also to exhibit the releasability between the paper and the fixing member such as the fixing film.

[0011] In order to improve the fixing film contamination and paper sticking during paper discharge and further improve the fixing property, the influence of wax is great, and the present inventors focused on the type of wax in particular for examination. Among them, from the viewpoint of fixing property, an ester wax having a polar group is advantageous, and among them, a diester wax is excellent. The inventors proceeded with the study on the premise of applying diester wax. Since diester wax has excellent compatibility with the binder resin, during heat fixing, the wax that oozes out onto the surface of the toner particles tends to maintain a compatible state and is rather unlikely to exhibit mold release properties. Therefore, it was found that it tends to adhere partially to fixing members such as the fixing film and cause member contamination, and it is difficult to achieve both good fixing performance and film cleanliness.

[0012] On the other hand, the paper sticking will be described in detail. First, consider the state of the toner on the printed matter. When within several minutes after the printed matter is output, the printed matter has a temperature of several tens of degrees Celsius. At that time, if the toner on the printed matter is simply in a plasticized state, the toner is in a semi-molten state and still has adhesiveness to the paper. If it remains semi-molten and touches new paper or is further pressed, part of the new paper and the toner will adhere to each other. To suppress such paper sticking, it is important to increase the viscosity of the softened toner after output and to improve the mold release property of the semi-molten toner from the paper. However, both are in a trade-off relationship with the fixing performance, and it is difficult to achieve both. Therefore, as a result of intensive studies, the inventors have found that the above problems can be solved by adjusting the relationship between the distribution coefficient of the shell layer of the toner and that of the diester wax within a certain range.

[0013] That is, the present disclosure relates to a toner having core particles containing a binder resin and a diester wax, and toner particles having a shell formed on the surface of the core particles, when the distribution coefficient of the shell is Sp and the distribution coefficient of the diester wax is Wp it relates to a toner that satisfies the following formulas (1) and (2). Sp ≦ 0.40 ···(1) 16.00 ≦ Wp - Sp ≦ 20.00 ···(2)

[0014] Here, the distribution coefficient was examined using the one calculated from the gasteiger charges calculated according to the following paper. Iterative partial equalization of orbital electronegativity - a rapid access to atomic charges, Tetrahedron 1980, 36, 3219.

[0015] The partition coefficient is generally an index representing the hydrophobicity and migration property of a chemical substance. Although it can be determined experimentally, in the present disclosure, the octanol / water partition coefficient is calculated computationally. Specifically, it is calculated by the following procedure. Specifically, the partial charge and the partition coefficient can be calculated by Advanced Chemistry Development (ACD / Labs) Software V11.02 (c1994 - 2016 ACD / Labs). Here, a small value of the partition coefficient indicates low hydrophobicity, that is, hydrophilicity. The above formula (1) indicates that the shell is hydrophilic, and the above formula (2) indicates that the difference in hydrophobicity between the wax and the shell is within a certain range. Regarding the reason why the fixing film stain and paper sticking are improved when formulas (1) and (2) are satisfied simultaneously, the inventors consider as follows.

[0016] When formulas (1) and (2) are satisfied, when the diester wax oozes out to the surface of the toner particles during heat fixing, the shell and the wax phase - separate on the surface of the toner particles, and the wax becomes droplets, exhibiting excellent releasability, so the fixing film stain is significantly improved. Furthermore, due to the presence of the wax droplets on the surface of the toner particles, not only is the releasability high, but also the crystallization after heat fixing proceeds rapidly. Therefore, by quickly becoming a state like wax, when printing materials are stacked, the releasability from other papers is greatly enhanced, and the paper sticking is significantly improved.

[0017] When Sp in formula (1) exceeds 0.40, the shell becomes more hydrophobic. Therefore, the wax and the shell that ooze out during heat fixing are likely to be compatible, resulting in a decrease in releasability, and both the fixing film stain and paper sticking are likely to occur. Sp is preferably 0.10 or less, more preferably 0.05 or less. The lower limit of Sp is preferably -0.10 or more, more preferably -0.05 or more.

[0018] When Wp - Sp in formula (2) is less than 16.00, the wax and the shell are more likely to blend, and the formation of wax droplets on the toner particle surface is inhibited, so that fixing film contamination and paper sticking are likely to occur. When Wp - Sp exceeds 20.00, the shell hardly blends with the wax and has a strong shielding effect. Therefore, even the wax that oozes out during heat fixing is shielded, and the fixability is greatly reduced. Wp - Sp is preferably from 16.00 to 19.00, more preferably from 16.00 to 17.00. Note that the partition coefficients of the shell, wax, and binder resin can be controlled by adjusting the molecular structure. Specifically, when the number of highly polar functional groups (for example, sulfonic acid, amino group, hydroxyl group, carboxyl group, etc.) in one molecule increases, the numerical value decreases. In order to make the hygroscopicity appropriate and to prevent the formation of a portion that is difficult to locally affinity with the wax, it is preferable to select a material having an appropriate polarity as the material of the shell. Particularly with respect to the shell, it is preferable to adjust with an amino group.

[0019] The shell used in the toner is not particularly limited as long as it can satisfy the above formulas (1) and (2), and resin components such as known thermosetting resins and thermoplastic resins can be used. 。 The shell preferably contains a thermosetting resin, and more preferably is a thermosetting resin. When the shell contains a thermosetting resin, it can maintain high elasticity even when the wax oozes out, and the releasability is further enhanced.

[0020] Also, the shell preferably contains a crosslinking component. Specifically, the content ratio of the insoluble matter in the shell with respect to tetrahydrofuran is preferably 5% by mass or more and 95% by mass or less. When the content ratio is within the above range, it is preferable because it is easy to balance the effect of maintaining the above-described elasticity and the fixing property. More preferably, it is 10% by mass or more and 90% by mass or less, and still more preferably, it is 50% by mass or more and 80% by mass or less.

[0021] The insoluble matter in the shell with respect to tetrahydrofuran (THF) can be analyzed as follows. First, measure the composition of the core and the shell by surface analysis such as TOF-SIMS or pyrolysis GC / MS. Then, dissolve the toner in tetrahydrofuran to obtain a dissolved resin component and an insoluble resin component. When components insoluble in tetrahydrofuran such as magnetite and silica fine particles are included, separate them using centrifugation, magnetic force, or the like. At this time, record the ratio of the insoluble resin component in the toner. Since the above THF-insoluble resin component contains both a shell-derived component and a binder resin-derived component, determine the composition ratio of the shell and the binder resin using an analyzer such as pyrolysis GC / MS. Then, the content ratio of the THF-insoluble matter in the shell can be obtained from the ratio of the shell in the analyzed toner, the amount of THF-insoluble matter, and the component ratio of the shell in the THF-insoluble matter.

[0022] Preferable examples of the thermosetting resin include melamine resin, urea resin, and glyoxal resin. The thermosetting resin is preferably at least one selected from the group consisting of melamine resin and urea resin. More preferably, it is melamine resin. Melamine resin is a polycondensate of melamine and formaldehyde, and the monomer used for forming the melamine resin is melamine. Melamine is likely to be disposed as a shell on the surface of the toner particles, is less compatible with diester wax, and is likely to exhibit mold release properties, so it is easy to achieve the above effects.

[0023] Melamine resins are preferably methylol melamine resins, hexamethylol melamine resins, and methoxymethylol melamine resins. Urea resins are preferably methylolated urea resins.

[0024] The melting point of the diester wax is preferably 65 to 85 °C, more preferably 70 °C to 80 °C. When within the above range, the toner has excellent fixability.

[0025] Examples of the diester wax include esters of dicarboxylic acids and monoalcohols and esters of diols and monocarboxylic acids. Examples of the diol include 1,6 - hexanediol, 1,7 - heptanediol, 1,8 - octanediol, 1,9 - nonanediol, 1,10 - decanediol, 1,11 - undecanediol, and 1,12 - dodecanediol. Examples of the dicarboxylic acid include adipic acid, pimelic acid, suberic acid, azelaic acid, decanedioic acid, undecanedioic acid, and dodecanedioic acid. Here, linear fatty acids and linear alcohols are exemplified, but those having a branched structure may also be used.

[0026] As the monoalcohol to be condensed with the above dicarboxylic acid, aliphatic monoalcohols are preferred. Specifically, tetradecanol, pentadecanol, hexadecanol, heptade canol, octadecanol, nonadecanol, eicosanol, docosanol, tricosanol, tetracosanol, pentacosanol, hexacosanol, octacosanol, etc. Among them, docosanol is preferred from the viewpoints of fixability and developability.

[0027] As the monocarboxylic acid to be condensed with the above diol, an aliphatic monocarboxylic acid is preferable. Specifically, examples of the fatty acid include lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, tuberculostearic acid, arachidic acid, behenic acid, lignoceric acid, and cerotic acid. Among them, stearic acid and behenic acid are preferable from the viewpoints of fixing property and developability. The diester wax is preferably a compound represented by the following formula (A).

[0028]

Chemical formula

[0029] In the above formula (A), R 1 represents an alkylene group having 2 to 12 carbon atoms (preferably 2 to 8 carbon atoms, more preferably 2 to 4 carbon atoms). R 2 and R 3 represent linear alkyl groups having 15 to 25 carbon atoms (preferably 16 to 22 carbon atoms, more preferably 16 to 20 carbon atoms), and R 2 and R 3 are independent of each other. Examples of the diol that supplies the partial structure represented by the formula (A) include ethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, and 1,12-dodecanediol. Among them, ethylene glycol and 1,9-nonanediol are preferable. Among them, ethylene glycol in which R 1 is an alkylene group having 2 carbon atoms, that is, an ethylene group, is more preferable from the viewpoints of compatibility with the binder resin and ease of bleeding during heat fixing.

[0030] As the monocarboxylic acid to be condensed with the above diol, an aliphatic monocarboxylic acid is preferred. Specifically, examples of fatty acids include lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, tuberculostearic acid, arachidic acid, behenic acid, lignoceric acid, and cerotic acid. Among them, stearic acid and behenic acid are preferred from the viewpoints of fixing property and developability.

[0031] The diester wax preferably contains a compound represented by the formula (A) as a main component. The main component means that its content is 50% by mass or more. More preferably, the diester compound represented by the formula (A) is contained in the diester wax in an amount of 95% by mass or more and 100% by mass or less. Also, the content of the diester wax is preferably 2 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the binder resin. More preferably, it is 4 parts by mass or more and 25 parts by mass or less, still more preferably 5 parts by mass or more and 22 parts by mass or less, and even more preferably 10 parts by mass or more and 22 parts by mass or less.

[0032] The melting point of the diester wax is preferably 60°C or higher and 90°C or lower, and more preferably 65°C or higher and 80°C or lower. When it is 65°C or higher, it is easy to suppress paper jamming, and when it is 90°C or lower, it is easy to prevent contamination of the fixing film. In addition to the diester wax, the toner particles may contain other known waxes to the extent that the above effects are not inhibited. For example, paraffin wax may be used as the wax. The content of the other wax is preferably 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin.

[0033] Specific production examples of the diester wax represented by the formula (A) are shown below. First, the raw material alcohol and carboxylic acid are added to a reaction vessel. The molar ratio of the alcohol and the carboxylic acid is appropriately adjusted according to the chemical structure of the target wax. In consideration of the reactivity in the dehydration condensation reaction, etc., either the alcohol or the carboxylic acid may be added slightly in excess of the above ratio. Next, the mixture is heated as appropriate to carry out a dehydration condensation reaction. To the crude esterification product obtained by the dehydration condensation reaction, a basic aqueous solution and, as appropriate, an organic solvent are added to deprotonate unreacted alcohol and carboxylic acid and separate them into the aqueous phase. Subsequently, by appropriately performing water washing, solvent evaporation, and filtration, the desired diester wax can be obtained.

[0034] The binder resin that can be used in the toner is not particularly limited, and known resins for toner can be used. Specifically, vinyl resins, styrene resins, styrene copolymer resins, polyester resins, polyol resins, polyvinyl chloride resins, phenol resins, natural resin-modified phenol resins, natural resin-modified maleic acid resins, acrylic resins, methacrylic resins, polyvinyl acetate, silicone resins, polyurethane resins, polyamide resins, furan resins, epoxy resins, xylene resins, polyvinyl butyral, terpene resins, coumarone indene resins, petroleum resins, etc. can be mentioned. Preferably, styrene copolymer resins, polyester resins, hybrid resins in which a polyester resin and a vinyl resin are mixed or in which the two have partially reacted, etc. can be mentioned. Among these, from the viewpoint of compatibility with the diester wax, a polyester resin or a vinyl resin is preferable, and a polyester resin is more preferable.

[0035] The binder resin preferably contains a polyester resin, and it is preferable from the viewpoint of low-temperature fixability that the polyester resin is the main component. The main component means that its content is 50% by mass to 100% by mass (preferably 80% by mass to 100% by mass). It is more preferable that the binder resin is a polyester resin.

[0036] As the monomers used in the polyester resin, polyhydric alcohols (diols or triols or higher) and polyvalent carboxylic acids (diacids or triacids or higher), their acid anhydrides or their lower alkyl esters are used. As the polyhydric alcohol monomer used in the polyester unit of the polyester resin, the following polyhydric alcohol monomers can be used. As the dihydric alcohol component, ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, hydrogenated bisphenol A, and bisphenol represented by the formula (A) and its derivatives;

[0037]

Chemical formula

[0038] (In the formula, R is an ethylene or propylene group, and x and y are each an integer of 0 or more and the average value of x + y is 0 or more and 10 or less.) Diols represented by the formula (B) are exemplified.

[0039]

Chemical formula

[0040] As the alcohol component having three or more valences, 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-trihydroxymethylbenzene are exemplified. Among these, preferably glycerol, trimethylolpropane, and pentaerythritol are used. These dihydric alcohols and alcohols having three or more valences can be used alone or in combination of two or more.

[0041] As the polyvalent carboxylic acid monomer used in the polyester unit of the polyester resin, the following polyvalent carboxylic acid monomers can be used. Examples of the divalent carboxylic acid component include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic 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-octenyl succinic acid, n-octyl succinic acid, isooctenyl succinic acid, isooctyl succinic acid, anhydrides of these acids, and lower alkyl esters of these acids. Among these, maleic acid, fumaric acid, terephthalic acid, and n-dodecenyl succinic acid are preferably used. Examples of the polyvalent carboxylic acid having a valence of 3 or more, its acid anhydride, or its lower alkyl ester include 1,2,4-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,2,4-cyclohexanetricarboxylic acid, tetra(methylene carboxyl)methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, Empol trimer acid, anhydrides of these acids, or lower alkyl esters of these acids. Among these, in particular, 1,2,4-benzenetricarboxylic acid, that is, trimellitic acid or its derivative is inexpensive and easy to control the reaction, so it is preferably used. These divalent carboxylic acids and polyvalent carboxylic acids having a valence of 3 or more can be used alone or in combination of two or more.

[0042] The method for producing the polyester resin is not particularly limited, and known methods can be used. For example, the aforementioned alcohol monomer and carboxylic acid monomer are charged simultaneously, and polymerized through an esterification reaction or transesterification reaction, and a condensation reaction to produce a polyester resin. Also, the polymerization temperature is not particularly limited, but a range of 180°C or higher and 290°C or lower is preferable. When polymerizing the polyester resin, for example, polymerization catalysts such as titanium-based catalysts, tin-based catalysts, zinc acetate, antimony trioxide, and germanium dioxide can be used. In particular, as the binder resin, a polyester resin polymerized using a tin-based catalyst is more preferable.

[0043] Also, the partition coefficient of the binder resin may be controlled. Specifically, when the partition coefficient of the binder resin is Bp, the difference (Wp - Bp) between the partition coefficient Wp of the diester wax and the partition coefficient Bp of the binder resin is preferably 15.80 or less. When Wp - Bp is within this range, the compatibility between the binder resin and the diester wax increases, resulting in excellent fixing properties. Wp - Bp is more preferably 15.60 or less, and even more preferably 14.00 or less. The lower limit is not particularly limited, but is preferably 8.00 or more, and more preferably 10.00 or more.

[0044] For the toner, various known colorants can be used. In the case of a black toner, using a magnetic material is preferable because the influence on the behavior of the wax is small and the above effects are easily achieved.

[0045] Hereinafter, an example of the method for producing the toner will be described. For producing the core particles of the toner, various methods such as a grinding method, a suspension polymerization method, and an aggregation method can be used. From the viewpoints of simplicity and material selectivity, the grinding method is preferable. An example of the pulverization method will be described below. First, a binder resin, a diester wax, and additives such as a colorant and a charge control agent, if necessary, are mixed using a stirring device such as a Henschel mixer. Subsequently, the obtained mixture is melt-kneaded, and then coarsely pulverized and pulverized, and the obtained pulverized product is classified. Thereby, toner core particles having a desired particle diameter are obtained.

[0046] Next, a shell is formed on the surface of the obtained toner core particles. The shell is formed, for example, by dispersing a material for forming the shell in an aqueous medium and adsorbing it on the surface of the toner core particles. The shell material may be dissolved in the aqueous medium. Further, a polar medium (for example, an alcohol such as methanol or ethanol) may be mixed in the aqueous medium. The shell does not necessarily have to cover the entire surface of the core particles, and there may be a portion where the core particles are exposed.

[0047] As the shell material, various materials such as a thermoplastic resin, a thermosetting resin, and silica fine particles can be used. From the viewpoint of easily obtaining the above effects, it is preferable to use a thermosetting resin as the main component. The thermosetting resin is preferably a urea resin or a melamine resin.

[0048] By going through the above-described steps, a dispersion of toner particles is obtained. Thereafter, if necessary, toner particles are obtained through filtration, a drying step, and a classification step. Further, if necessary, a mixer (for example, an FM mixer manufactured by Nippon Coke & Engineering Co., Ltd.) may be used to mix the toner particles and an external additive so that the external additive adheres to the surface of the toner particles. Note that the content and order of the above toner manufacturing method can be arbitrarily changed according to the required toner configuration or characteristics, etc.

[0049] Next, the measurement methods for each physical property will be described. <Measurement Method for Melting Point of Wax> Weigh 5 mg of the wax sample into the sample holder and perform measurements under the following conditions using a differential scanning calorimeter DSC Q2000 (manufactured by TA Instruments). Measurement start temperature: 20 °C Measurement end temperature: 180 °C Heating rate: 10 °C / min In the obtained DSC curve, take the peak top as the melting point.

[0050] <Volume average particle diameter Dv of toner particles> The volume average particle diameter Dv, number average particle diameter Dn, and particle size distribution Dv / Dn of the toner particles are measured using a particle size analyzer (manufactured by Beckman Coulter, product name: Multisizer). The measurement by this Multisizer is performed under the conditions of aperture diameter: 100 μm, dispersion medium: Isoton II (: product name), concentration 10%, and number of measured particles: 100,000. Specifically, take 0.2 g of the toner particle sample in a beaker, and add an aqueous solution of alkylbenzene sulfonic acid (manufactured by Fujifilm, product name: Drywell) as a dispersant thereto. Then, add 2 mL of the dispersion medium, wet the toner particles, add 10 mL of the dispersion medium, disperse for 1 minute with an ultrasonic disperser, and then perform measurement with the above particle size measuring instrument.

[0051] <Structural analysis of the shell in the toner> The structural analysis of the shell in the toner can be performed using a time-of-flight secondary ion mass spectrometer (TOF-SIMS). Use the following device under the following conditions to identify the partial structure from the fragment peaks of the toner shell. · Measuring device: TRIFT-IV (product name, manufactured by ULVAC-PHI, Inc.) · Primary ion: Appropriately selected from Bi and Au · Raster size: 100 μm × 100 μm · Neutralizing electron gun: Used

[0052] <Composition analysis of the wax> The composition analysis of the wax in the toner particles is performed using a nuclear magnetic resonance apparatus ( 1 H-NMR, 13It can be carried out using (C-NMR). The apparatus used below is described. Each sample can be collected by separating it from the toner and analyzed. Nuclear magnetic resonance apparatus ( 1 H-NMR, 13 C-NMR) Measuring device: FT NMR device JNM-EX400 (manufactured by JEOL Ltd.) Measuring frequency: 400 MHz Pulse condition: 5.0 μs Frequency range: 10500 Hz Number of integrations: 64 times

Example

[0053] Hereinafter, the present invention will be described in more detail using examples and comparative examples. The present invention is not limited in any way by the following examples. In the description of the following examples, "parts" means parts by mass unless otherwise specified.

[0054] The ester wax used in the examples is shown in Table 1.

[0055]

Table 1

[0056] <Production Example of Toner 1> (Production of Polyester Resin 1) The following materials were mixed in a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen inlet tube. · Polyoxypropylene (2.2)-2,2-bis(4-hydroxyphenyl)propane 58.0 parts · Ethylene glycol 8.0 parts · Terephthalic acid 31.0 parts · Trimellitic anhydride 3.0 parts · Dibutyltin oxide 0.3 part After replacing the system with nitrogen by a vacuum operation, it was heated to 210 °C, and nitrogen was introduced to react for 5 hours while removing the generated water. Then, while continuing stirring, the temperature was gradually raised to 230 °C under reduced pressure, and the reaction was further continued for 3 hours to synthesize polyester resin 1. The weight average molecular weight Mw was 9,500, and the Tg was 68 °C.

[0057] (Manufacture of magnetic material) Fe 2+ 92 L of an aqueous ferrous sulfate solution with a concentration of 1.79 mol / L and 88 L of an aqueous sodium hydroxide solution with a concentration of 3.74 mol / L were added and mixed with stirring. The pH of this solution was 6.5. While maintaining this solution at a temperature of 89 °C and a pH of 9 to 12, air was blown in at 20 L / min to cause an oxidation reaction to generate core particles. When the ferrous hydroxide was completely consumed, the blowing of air was stopped and the oxidation reaction was terminated. The obtained magnetic core particles composed of magnetite had an octahedral shape. The shape of the magnetic material was octahedral, and the number average particle size (D1) was 120 nm.

[0058] (Manufacture of toner core particles 1) The following materials were thoroughly mixed with an FM mixer (manufactured by Nippon Coke & Engineering Co., Ltd.), and then melt-kneaded with a twin-screw kneader (manufactured by Ikegai Iron Works Co., Ltd.). · Polyester resin 1: 100.0 parts · "Acrybase (registered trademark) FCA-201-PS" manufactured by Fujikura Kasei Co., Ltd.: 3.0 parts · HNP-9 (melting point: 76 °C, manufactured by Nippon Seiro Co., Ltd.): 5.0 parts · Wax 1: 15.0 parts · Magnetic material: 100.0 parts The obtained kneaded product was cooled and coarsely pulverized to 1 mm or less with a hammer mill to obtain a coarsely pulverized product. Next, the obtained coarsely pulverized product was finely pulverized to about 5 μm using a turbo mill manufactured by Turbo Industry Co., Ltd., and then the fine coarse powder was cut using a multi-division classifier utilizing the Coanda effect to obtain toner core particles 1. The weight average particle size (D4) of the toner core particles 1 was 6.8 μm, and the Tg was 58 °C.

[0059] (Production of Toner Particle Dispersion Liquid 1) After maintaining a reaction vessel containing 300.0 parts of ion-exchanged water at 30°C, dilute hydrochloric acid was added to adjust the pH to 5.1. After pH adjustment, the following materials were added and dissolved to obtain an aqueous medium. 2.0 parts of an aqueous solution of methylol melamine, Milliben resin SM-607 (manufactured by Showa Denko K.K., solid content concentration 80%) To the aqueous medium, 200.0 parts of toner core particles 1 were added, and the reaction vessel was stirred at a speed of 200 rpm, and the contents of the flask were stirred for 1 hour under the condition of a temperature of 40°C. Subsequently, 90 parts of ion-exchanged water were added to the flask, and while stirring the contents of the flask at 100 rpm, the temperature inside the flask was raised to 70°C, and the contents of the flask were stirred for 2 hours under the conditions of a temperature of 70°C and a rotation speed (agitation blade) of 100 rpm. As a result, a toner particle dispersion liquid 1 in which toner particles having a shell layer formed on the surface of the core particles were dispersed was obtained.

[0060] (Extraction of Toner Particles 1) After neutralizing the toner particle dispersion liquid 1, cooling it to room temperature (about 25°C), and filtering it, it was dispersed again in ion-exchanged water. Dispersion and washing were repeated until the electrical conductivity of the ion-exchanged water sufficiently decreased to obtain cake-like toner particles. Then, this was crushed and placed in a constant temperature bath at 40°C for 70 h and sufficiently dried to obtain toner particles 1 as a powder.

[0061] (Production of Toner 1) Using an FM mixer (「FM-10B」manufactured by Nippon Coke & Engineering Co., Ltd.), 100 parts of toner particles and 1 part of hydrophobic silica particles (using 3-aminopropyltriethoxysilane and dimethyl silicone oil as hydrophobizing agents) were mixed for 5 minutes under the condition of a rotation speed of 3500 rpm. Thereafter, coarse particles were removed using a 300-mesh (aperture 48 μm) sieve to obtain toner 1. The physical properties and formulations are shown in Tables 2 and 3.

[0062] (Production Examples of Toners 2 to 10) In the production example of toner 1, the same procedure was carried out except that the type and amount of ester wax were changed as shown in Table 2 to obtain toners 2 to 10.

[0063] <Production Example of Toner 11> In the production example of Toner 1, except that the type and amount of the ester wax were changed as shown in Table 2 and the pH of the aqueous medium was adjusted to 4.6 in the production of the toner particle dispersion 1, the same procedure was carried out to obtain Toner 11.

[0064] <Production Example of Toner 12> In the production example of Toner 1, except that the type and amount of the ester wax were changed as shown in Table 2 and the pH of the aqueous medium was adjusted to 5.7 in the production of the toner particle dispersion 1, the same procedure was carried out to obtain Toner 12.

[0065] <Production Example of Toner 13> In the production example of Toner 1, except that the type and amount of the ester wax were changed as shown in Table 2 and the pH of the aqueous medium was adjusted to 5.8 in the production of the toner particle dispersion 1, the same procedure was carried out to obtain Toner 13.

[0066] <Production Example of Toner 14> In the production example of Toner 13, except that the pH of the aqueous medium was adjusted to 4.0 in the production of the toner particle dispersion 1, the same procedure was carried out to obtain Toner 14.

[0067] <Production Example of Toner 15> In the production example of Toner 14, except that the type and amount of the ester wax were changed as shown in Table 2, the same procedure was carried out to obtain Toner 15, respectively.

[0068] <Production Example of Toner 16> In the production example of Toner 14, except that the polyester resin 1 was changed to the styrene-acrylic resin 1 produced by the following production method, the same procedure was carried out to obtain Toner 16.

[0069] (Production of Styrene-Acrylic Resin 1) In a reaction vessel equipped with a condenser, a stirrer, and a nitrogen inlet tube, the following materials were mixed and the temperature was raised while stirring and maintained at 180 °C. · Styrene 78.0 parts · n-Butyl acrylate 20.0 parts · 2.0 parts of acrylic acid · 300.0 parts of xylene Subsequently, 50.0 parts of a xylene solution of 2.0 mass% t-butyl hydroperoxide was continuously dropped into the system over 4.5 hours. After cooling, the solvent was separated and removed to synthesize Styrene Acrylic Resin 1. The weight average molecular weight Mw was 14,500 and the Tg was 65°C.

[0070] <Production Example of Toner 17> In the production of Toner 16, the same procedure was carried out except that the ester wax type and amount were changed as shown in Table 2 to obtain Toner 17.

[0071] <Production Example of Toner 18> <Production of Silane Compound> 30 parts of iso-butyltrimethoxysilane was dropped into 70 parts of ion-exchanged water while stirring. Thereafter, this aqueous solution was maintained at pH 5.5 and temperature 55°C, and dispersed at a peripheral speed of 0.46 m / s for 120 minutes using a dispersing blade to carry out hydrolysis. Thereafter, the pH of the aqueous solution was adjusted to 7.0 and cooled to 10°C to stop the hydrolysis reaction. Thus, an aqueous solution 1 containing a silane compound was obtained.

[0072] <Production of Hydrophobically Treated Magnetic Body> 100 parts of a magnetic body was placed in a high-speed mixer (LFS-2 type manufactured by Fukae Powtec Co., Ltd.), and while stirring at a rotational speed of 2000 rpm, 8.0 parts of the aqueous solution 1 containing a silane compound was dropped over 2 minutes. Thereafter, it was mixed and stirred for 5 minutes. Next, in order to enhance the fixing property of the silane compound, it was dried at 40°C for 1 hour to reduce the moisture content, and then the mixture was dried at 110°C for 3 hours to advance the condensation reaction of the silane compound. Thereafter, it was crushed and passed through a sieve with an opening of 100 μm to obtain a hydrophobically treated magnetic body 1.

[0073] 450 parts of 0.1 mol / L - Na3PO4 aqueous solution was added to 720 parts of ion-exchanged water and heated to 60°C, and then 67.7 parts of 1.0 mol / L - CaCl2 aqueous solution was added to obtain an aqueous medium containing a dispersion stabilizer. · 76.0 parts of styrene · 24.0 parts of n-butyl acrylate · 0.2 part of divinylbenzene · 90.0 parts of hydrophobized magnetic material 1 · 3.0 parts of amorphous saturated polyester resin (Amorphous saturated polyester resin obtained by condensation reaction of ethylene oxide and propylene oxide adduct of bisphenol A with terephthalic acid; Mw = 9500, acid value = 6 mg KOH / g) The above materials were uniformly dispersed and mixed using an attritor (manufactured by Nippon Coke & Engineering Co., Ltd.) to obtain a monomer composition. This monomer composition was heated to 63°C, and 3 parts of ester wax 7 and 5 parts of HNP-9 (manufactured by Nippon Seiro Co., Ltd.) were mixed and dissolved therein. The above monomer composition was introduced into the above aqueous medium, and stirred at 12000 rpm for 10 minutes using a T.K. homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) at 60°C under a nitrogen atmosphere to granulate. Then, while stirring with a paddle stirring blade, 8.0 parts of the polymerization initiator t-butyl peroxy pivalate was added, the temperature was raised to 70°C and reacted for 4 hours, and then cooled to room temperature to obtain a toner particle dispersion liquid 18.

[0074] Next, the following samples were weighed into a reaction vessel and mixed using a propeller stirring blade. · Toner particle dispersion liquid 18: 500.0 parts · Aqueous solution of methylol melamine, Milliben resin SM-607 (solid content concentration 80%): 0.6 part After adjusting the temperature of the mixed solution to 30°C, it was mixed at 200 rpm using a propeller stirring blade and held for 1.0 hour. Then, while stirring with a propeller stirring blade, it was raised to 80°C at a rate of 1°C / min and held for 2 hours. Subsequently, using 1 mol / L aqueous NaOH solution, the pH of the obtained mixed solution was adjusted to 7.0. Next, after cooling until the temperature of the content reached room temperature (about 25°C), the pH was adjusted to 1.5 with 1 mol / L hydrochloric acid, stirred for 1.0 hour, and then washed with ion-exchanged water while filtering and drying, and fine powder and coarse powder were removed by air classification to obtain toner particles 18. Next, using an FM mixer ("FM-10B" manufactured by Nippon Coke & Engineering Co., Ltd.), 100 parts of toner particles 18 and 1 part of hydrophobic silica particles (using 3-aminopropyltriethoxysilane and dimethyl silicone oil as hydrophobizing agents) were mixed for 5 minutes under the condition of a rotational speed of 3500 rpm. Thereafter, coarse particles were removed using a 300-mesh (aperture 48 μm) sieve to obtain toner 18. The physical properties and formulation are shown in Table 2.

[0075] <Production Example of Toner 19> In the production of the toner particle dispersion liquid 1 of toner 1, without performing pH adjustment, without using methylol melamine, and except for forming a shell by appropriately controlling the temperature and pH after using the following resin fine particle dispersion liquid 1 in the same manner, toner 19 was obtained. The addition amount of the resin fine particle dispersion liquid was set to an amount that would disperse all the toner particles.

[0076] (Production of Resin Fine Particle Dispersion Liquid 1) 30 parts of acetone was placed in a reaction vessel equipped with a cooling pipe, a stirrer, a thermometer, and a nitrogen inlet pipe, and stirred. · 15.0 parts of 2-acrylamido-phenylsulfonic acid methyl ester · 68.8 parts of styrene · 15.0 parts of n-butyl acrylate · 1.2 parts of acrylic acid The above materials were charged into the reaction vessel and dissolved. After heating the inside of the reaction vessel to 60 °C, 2.0 parts of 2,2-azobis(2,4-dimethylvaleronitrile) was added as a polymerization initiator and reacted for 8 hours. After cooling the reaction solution, it was concentrated and dried by an evaporator, and further dried in a vacuum dryer at 40 °C for 10 hours to obtain a resin. The obtained resin was dissolved again in acetone to prepare a solid content ratio of 75% by mass. Then, it was dropped into 100 parts of ion-exchanged water while stirring to be emulsified, and further, acetone was distilled off under a reduced pressure of 100 mmHg inside the reaction vessel. It was diluted to a solid content ratio of 15% by mass to obtain resin fine particle dispersion liquid 1.

[0077] <Production Example of Toner 20> In the production example of toner 19, toner 20 was obtained in the same manner except that the following PMMA particle dispersion was used instead of the resin fine particle dispersion 1. (Production of PMMA Particle Dispersion) · PMMA (polymethyl methacrylate) particles (manufactured by Soken Chemical & Engineering Co., Ltd., MP-1451, Tg = 128°C): 70 parts · Anionic surfactant (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., Neogen RK): 30 parts · Ion-exchanged water: 200 parts The above materials were mixed and dispersed for 10 minutes using a high-power ultrasonic homogenizer (VCX-750). Ion-exchanged water was added so that the solid content in the dispersion became 20% by mass, and a PMMA particle dispersion in which PMMA particles with a volume average particle diameter of 150 nm were dispersed was obtained.

[0078] <Production Example of Toner 21> In the production example of toner 18, the pH of the toner particle dispersion 18 was adjusted to 1.5 with hydrochloric acid, stirred for 1.0 hour, then washed with ion-exchanged water while filtering, drying, and removing fine powder and coarse powder by air classification to obtain toner particles 21. When the surface of the toner particles 21 was observed and analyzed, a shell made of polyester resin was formed. Next, using an FM mixer (FM-10B manufactured by Nippon Coke & Engineering Co., Ltd.), 100 parts of toner particles 21 and 1 part of hydrophobic silica particles (using 3-aminopropyltriethoxysilane and dimethyl silicone oil as hydrophobizing agents) were mixed for 5 minutes under the condition of a rotation speed of 3500 rpm. After that, coarse particles were removed using a 300-mesh (aperture 48 μm) sieve to obtain toner 21. The physical properties and formulations are shown in Table 2.

[0079] <Production Examples of Toners 22 and 23>

[0079] In the production example of toner 14, toners 22 and 23 were obtained in the same manner except that the wax type and amount were changed as shown in Table 2.

[0080] <Examples 1 to 18, Comparative Examples 1 to 5> <Evaluation 1: Evaluation of Fixing Film Stain> For the evaluation of fixing film stain, HL-5470DW (manufactured by Brother Industries) was used. Immediately after continuously printing 50 solid black images in a normal temperature and humidity environment, 3 solid white images were printed, and the degree of stain on the solid white was used for judgment. When fixing a high-printed image such as a solid black image, some toner that cannot be completely separated from the fixing film adheres to the fixing film and is carried along. Immediately after printing a solid white image, the toner on the fixing film transfers to the paper and appears as a stain on the paper. The image was confirmed with an optical microscope and evaluated according to the following criteria. The evaluation results are shown in Table 3. A to C were judged to be good. A: No stain. B: There is stain, but only in the form of dots. C: There is stain, but there are two or more minor stains. D: There is stain, and minor stains are present throughout the surface, or obvious stains that can be easily seen are observed.

[0081] <Evaluation 2: Evaluation of Paper Jam Adhesion> For the evaluation of paper jam adhesion, HL-5470DW (manufactured by Brother Industries) was used. In a high temperature and high humidity environment (temperature 32.5°C, humidity 80%), the chart in Figure 1 was printed on both sides 100 times. When the solid black part and the text part were left in contact, if paper jam adhesion occurred, the toner would bind together, resulting in missing characters or white spots in the solid black part. After leaving it on the paper output tray for 10 minutes, the printed matter was evaluated according to the following criteria. The evaluation results are shown in Table 3. A to D were judged to be good. A: There are no missing characters or white spots in the solid part. B: There are missing characters or minor white spots in the solid part in the form of dots. The number of images with white spots is within 5 in total. C: There are missing characters or minor white spots in the solid part in the form of dots. The number of images with white spots is 6 to 10 in total. D: There are missing characters or minor white spots in the solid part in the form of dots. The number of images with white spots is 11 to 15 in total. E: There are missing characters, and obvious white spots in the form of dots and lines in the solid part.

[0082] <Evaluation 3: Evaluation of Fixing Temperature Range (Fixing Property)> For the evaluation of low-temperature fixability, the fixing unit of HL-5470DW (manufactured by Brother Industries) was taken out externally, the temperature of the fixing unit was made arbitrarily settable, and an external fixing unit modified so that the process speed became 400 mm / sec was used. Using the above device, an unfixed image with a toner loading amount per unit area set to 1.0 mg / cm 2 was passed through the above fixing unit with arbitrarily adjusted temperature. As the recording medium, "Prover Bond Paper" (105 g / m 2 , manufactured by Fox River) was used. Fixability was evaluated by the width of the fixable temperature range. The low-temperature fixable temperature was judged by the occurrence of low-temperature offset where the solid image became white and spotty, and the high-temperature fixable temperature was judged by the occurrence of high-temperature offset where repeated stains occurred at a pitch corresponding to the film diameter of the fixing unit in the non-image area. The evaluation results are shown in Table 3. A to D were judged to be good. A: The width of the fixable area is 30°C or more A: The width of the fixable area is 30 °C or more B: The width of the fixable area is 25 °C or more and less than 30 °C C: The width of the fixable area is 20 °C or more and less than 25 °C D: The width of the fixable area is 15 °C or more and less than 20 °C E: The width of the fixable area is less than 15 °C

[0083]

Table 2

[0084]

Table 3

Claims

1. A toner having toner particles including core particles containing a binder resin and a diester wax, and a shell formed on the surface of the core particles, wherein: the shell contains a melamine resin; the content of the diester wax is 4 parts by mass or more and 25 parts by mass or less with respect to 100 parts by mass of the binder resin; the toner is characterized in that when the partition coefficient of the shell is Sp and the partition coefficient of the diester wax is Wp, the following formulas (1) and (2) are satisfied. −0.10 ≤ Sp ≤ 0.40... (1) 16.00 ≤ Wp − Sp ≤ 20.00... (2)

2. The toner according to claim 1, wherein the diester wax is an ester of a diol and a monocarboxylic acid.

3. The toner according to claim 1 or 2, wherein the diester wax is a compound represented by the following formula (A). In the above formula (A), R １ represents an alkylene group having 2 to 12 carbon atoms. R ２ and R ３ represent linear alkyl groups having 15 to 25 carbon atoms, and R ２ and R ３ are independent of each other.

4. Said R １ The toner according to claim 3, wherein said R is an alkylene group having 2 carbon atoms.

5. The toner according to any one of claims 1 to 4, wherein the content ratio of the insoluble matter in the shell with respect to tetrahydrofuran is 5% by mass or more and 95% by mass or less.

6. The toner according to any one of claims 1 to 5, wherein the binder resin contains a polyester resin.

7. The toner according to any one of claims 1 to 6, wherein when the partition coefficient of the binder resin is Bp, the difference (Wp − Bp) between the partition coefficient Wp of the diester wax and Bp is 15.80 or less.

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