JP7472667B2 - Toner manufacturing method - Google Patents

Description

The present invention relates to a method for producing a toner.

The fixing method in the electrophotographic method is generally the heated roller method, which fixes the toner image by pressing a heated roller directly onto the recording medium, because of its energy efficiency. The heated roller method requires a large amount of power for fixing.

The heated roller method requires a wait time of about 10 seconds to raise the temperature of the heated roller from sleep mode to the temperature required for fixing, and this wait time is stressful for users. In addition, it is desirable to reduce power consumption by completely turning off the heater when no images are being output. In order to meet these demands, a toner that lowers the fixing temperature of the toner itself, lowers the fixing temperature of the toner when in use, and has high release properties is required.

Low-temperature fixing toners use low-melting resins and release agents, which makes them susceptible to contamination of components. In particular, when a large amount of low-melting release agent is present on the toner surface, the release agent adheres to the photoconductor, causing an image abnormality known as filming. On the other hand, when there is not enough release agent present on the toner surface, low-temperature fixing toners in particular are unable to exhibit sufficient release properties, which can easily lead to offset caused by toner adhering to the fixing roller or belt, or paper jams due to paper not peeling off after fixing.

In response to such problems, a method has been disclosed in which the amount of the release agent present on the surface of the toner particles is specified by the intensity ratio of the peak derived from the release agent to the peak derived from the binder resin, determined by FTIR-ATR (attenuated total reflection infrared spectroscopy), in the range of 0.01 to 0.40 (see, for example, Patent Document 1).
In addition to specifying the amount of release agent on the toner surface, a toner has been proposed in which the ratio of the release agent on the toner surface to the interior is specified by specifying the amount of release agent exposed by extraction with hexane to 18 mg/g or more and 30 mg/g or less, thereby controlling the arrangement of the release agent (see, for example, Patent Document 2).

The present invention aims to provide a toner that can produce stable images without filming caused by photoreceptor contamination, uneven gloss, or image abnormalities caused by hot offset.

The carrier of the present invention as a means for solving the above problems is a toner containing at least a binder resin and a release agent,
The amount of the release agent extracted with hexane is 31 mg/g or more and 95 mg/g or less,
The toner has an intensity ratio (P2850/P828) of a peak (P2850) derived from the release agent to a peak (P828) derived from the binder resin, which is determined by FTIR-ATR (attenuated total reflection infrared spectroscopy) at 25° C., of 0.05 or less.

The present invention provides a toner that can produce stable images without filming caused by photoreceptor contamination, uneven gloss, or image abnormalities caused by hot offset.

FIG. 1 is a schematic diagram showing an example of a cross section of the toner of the present invention.

(toner)
The toner of the present invention contains at least a binder resin and a release agent, and preferably contains a colorant, and further contains other components as necessary.
In the toner of the present invention, the amount of the release agent extracted with hexane is 30 mg/g or more and 90 mg/g or less, and the intensity ratio (P2850/P828) of the peak derived from the release agent (P2850) to the peak derived from the binder resin (P828) determined by FTIR-ATR (attenuated total reflection infrared spectroscopy) at 25° C. is 0.05 or less.

The toner of Patent Document 1, which is a conventional technology, only specifies the amount of release agent present on the toner surface, and has a problem in that an excessive amount of release agent present on the toner surface makes it impossible to achieve both releasability and prevention of adverse effects of the release agent.
The toner of Patent Document 2, which is a conventional technology, has a problem in that the amount of release agent extracted during fixing is insufficient in an environment where low temperature fixing and high speed fixing are becoming more common, resulting in deterioration of fixing properties and image abnormalities such as hot offset.
In this way, it is necessary to ensure a sufficient amount of release agent extracted during fixing while suppressing the amount of release agent on the toner surface. However, there is a trade-off between the amount of release agent on the toner surface and the amount of release agent extracted during fixing, and no manufacturing conditions have been established to date that achieve both.

After extensive research, the inventors discovered that by having a release agent inside the toner, it is possible to prevent filming onto the photoreceptor, and that the release agent seeps out onto the toner surface when the toner is fixed, thereby preventing the occurrence of hot offset.

The amount of the release agent extracted by the hexane is 31 mg/g or more and 95 mg/g or less, preferably 35 mg/g or more and 85 mg/g or less, more preferably 45 mg/g or more and 85 mg/g or less, and particularly preferably 60 mg/g or more and 85 mg/g or less. When the amount of extraction is 31 mg/g or more, excellent low-temperature fixability can be obtained and hot offset can be prevented. When the amount of extraction is 95 mg/g or less, uneven gloss in the image can be suppressed. The amount of extraction of the release agent is related to the amount of the release agent seeping out during fixing of the toner, and the more the amount of extraction of the release agent is, the more the release agent seeps out of the toner during fixing, and the more the occurrence of hot offset and paper jams can be prevented.
The amount of the release agent extracted by the extraction with hexane can be measured by the following method.
[Method for measuring the amount of release agent extracted]
7 mL of n-hexane is added to 1.0 g of toner, and the mixture is stirred at 120 rpm for 1 minute using a roll mill, and then suction filtered. After that, n-hexane is removed by vacuum drying, and the mass (mg) of the remaining component is measured as the amount of the release agent extracted.

The intensity ratio (P2850/P828) of the peak (P2850, wavelength: 2850 cm ^-1 ) derived from the release agent to the peak (P828, wavelength: 828 cm ^-1 ) derived from the binder resin, determined by FTIR-ATR (attenuated total reflection infrared spectroscopy) at 25°C, is 0.05 or less, and preferably 0.01 or more and 0.04 or less. When the intensity ratio (P2850/P828) is 0.05 or less, the amount of release agent on the toner surface is small, and the occurrence of filming can be suppressed.

The intensity ratio (P2850/P828) of the toner at 25° C. can be measured by an FTIR-ATR (attenuated total reflection infrared spectroscopy) method.
[Method for measuring intensity ratio (P2850/P828) at 25° C.]
The toner is pressed under conditions of 7.5 kN, 1 minute, and 25° C. using a tablet molding compressor (BRE-32, manufactured by Mayekawa Test Machinery Manufacturing Co., Ltd.) to form the toner into a disk. In the pressing, the absorbance of the release agent and binder resin present on the surface of the toner disk (peak derived from the release agent (P2850, wavelength: 2850 cm ⁻¹ ) and peak derived from the binder resin (P828, wavelength: 828 cm ⁻¹ ) respectively) is measured by an ATR method using Ge crystal using an FT-IR (manufactured by PerkinElmer). From the measured peak derived from the release agent and peak derived from the binder resin, the intensity ratio (P2850/P828) at 25° C. is calculated.

The intensity ratio (P2850/P828) of the peak (P2850, wavelength: 2850 cm ^-1 ) derived from the release agent to the peak (P828, wavelength: 828 cm ^-1 ) derived from the binder resin, determined by FTIR-ATR (attenuated total reflection infrared spectroscopy) at 120°C, is preferably 0.20 or more, and more preferably 0.30 or more. When the intensity ratio (P2850/P828) is 0.20 or more, the release agent melted by heating during toner fixing passes through pores and is exposed to the toner surface, thereby obtaining excellent low-temperature fixing properties and preventing the occurrence of hot offset.

The intensity ratio (P2850/P828) of the toner at 120°C can be calculated in the same manner as in the measurement method for the intensity ratio (P2850/P828) at 25°C, except that the toner is formed into a disk and then heated at 120°C for 1 minute.

The toner of the present invention preferably has pores on the surface. The pores refer to voids that are present in the toner particles and have a certain range of circle-equivalent diameters and are free of toner components such as binder resin and release agent. When the toner has pores on the surface, the release agent seeps out from inside the toner when the toner is fixed, and the occurrence of hot offset and paper jams can be prevented.
The average number of the pores is 0.5 or more and 11.0 or less, and preferably 4.0 or more and 9.0 or less. When the average number of the pores is 0.5 or more, the release agent exudes from the toner during fixing, which can prevent the occurrence of hot offset and paper jams. When the average number of the pores is 11.0 or less, the toner is prevented from collapsing due to contact between toner particles, and the release agent is prevented from being exposed before the toner is fixed, which can prevent the occurrence of filming.

The circle-equivalent diameter of the pores is preferably 0.2 μm or more and 3.0 μm or less. If the circle-equivalent diameter of the pores is 0.2 μm or more, the release agent seeps out of the toner during fixing, preventing the occurrence of hot offset and paper jams. If the circle-equivalent diameter of the pores is 3.0 μm or less, the toner can be prevented from collapsing due to contact between toner particles, and the release agent can be prevented from being exposed before the toner is fixed, preventing the occurrence of filming.

The average number and equivalent circle diameter of the pores on the surface of the toner can be measured by the following method.
[Method for measuring the average number and circle equivalent diameter of pores on the toner surface]
In evaluating the pores of the toner, since it is difficult to measure the average number and size of the pores of each toner particle, the average number and circle equivalent diameter of the pores in the cross section of the toner having the largest area were measured by the following method.
Specifically, the toner to be measured is embedded in a resin or the like, and then fixed and held on a support, and the surface of the toner-embedded resin is smoothed using an ultramicrotome (RM2265, manufactured by Leica). Then, a surface photograph of the resin on the support is taken using a scanning electron microscope (FE-SEM S-4800, manufactured by Hitachi, Ltd.). The obtained surface photograph is binarized using Photoshop, and the number of pores and the equivalent circle diameter in the entire cross section of the toner with the largest area are measured using image processing software (Image Plus Pro), and the average value relative to the number of toner particles is calculated. The equivalent circle diameter of the pores is calculated from the area of the pores obtained by image processing, and the equivalent circle diameter of cracks on the toner surface is calculated from the area of the gaps of the cracks. At least 300 toner particles are analyzed per sample.

Figure 1 is a cross-sectional view showing an example of the toner of the present invention photographed using a scanning electron microscope. As shown in Figure 1, the toner 10 of the present invention has pores 11. By having pores 11 on the surface of the toner 10, a release agent 12 seeps out from inside the toner when the toner is fixed, and the occurrence of hot offset and paper jams can be prevented.

<Release Agent>
The release agent is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include wax, silicone oil, etc. As the release agent, a substance is used that has a sufficiently low viscosity when heated in the fixing process and is not easily dissolved or swollen with other substances of the colored resin particles on the surface of the fixing member, and considering the storage stability of the colored resin particles themselves, wax is preferred because it exists as a solid in the colored resin particles during normal storage.

The wax is not particularly limited and may be appropriately selected depending on the purpose. Examples of the wax include long-chain hydrocarbons and carbonyl group-containing waxes. Among these, long-chain hydrocarbons are preferred because of their good releasability. When the long-chain hydrocarbons are used as a release agent, the carbonyl group-containing wax may be used in combination.
Examples of the long-chain hydrocarbons include polyolefin waxes (polyethylene wax, polypropylene wax, etc.); petroleum waxes (paraffin wax, sazol wax, microcrystalline wax, etc.); and Fischer-Tropsch wax.
Examples of the carbonyl group-containing wax include polyalkanoic acid esters (carnauba wax, montan wax, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18-octadecanediol distearate, etc.); polyalkanol esters (tristearyl trimellitate, distearyl maleate, etc.); polyalkanoic acid amides (ethylenediamine dibehenylamide, etc.); polyalkyl amides (tristearyl trimellitate amide, etc.); and dialkyl ketones (distearyl ketone, etc.).

The content of the release agent is preferably 1% by mass to 20% by mass, and more preferably 3% by mass to 10% by mass, based on the total toner. If the content of the release agent is 1% by mass or more, the problem of deterioration of offset properties can be prevented. Also, if the content is 20% by mass or less, the problem of increased melting of wax during fixing and increased generation of fine particles (UFP) can be prevented.

<Binder resin>
The binder resin is not particularly limited and can be appropriately selected according to the purpose, and examples thereof include polyester resin, silicone resin, styrene-acrylic resin, styrene resin, acrylic resin, epoxy resin, diene resin, phenol resin, terpene resin, coumarin resin, amide-imide resin, butyral resin, urethane resin, and ethylene vinyl acetate resin. These may be used alone or in combination of two or more. Among these, a resin obtained by combining at least one of a polyester resin and a polyester resin with another binder resin is preferred, in terms of excellent low-temperature fixing property and sufficient flexibility even when the molecular weight is reduced.

The polyester resin is not particularly limited and can be appropriately selected depending on the purpose. For example, unmodified polyester resin, modified polyester resin, etc. can be used. These may be used alone or in combination of two or more kinds.

The unmodified polyester resin is not particularly limited and can be appropriately selected depending on the purpose. For example, it can be a resin obtained by polyesterifying a polyol represented by the following general formula (1) and a polycarboxylic acid represented by the following general formula (2).

（ただし、前記一般式（１）中、Ａは、炭素数１～２０のアルキル基、アルキレン基、置換基を有してもよい芳香族基又はヘテロ環芳香族基を表し、ｍは、２～４の整数を表す。）

(In the above general formula (1), A represents an alkyl group, an alkylene group, an aromatic group or a heterocyclic aromatic group having 1 to 20 carbon atoms, which may have a substituent, and m represents an integer of 2 to 4.)

（ただし、前記一般式（２）中、Ｂは、炭素数１～２０のアルキル基、アルキレン基、置換基を有してもよい芳香族基又はヘテロ環芳香族基を表し、ｎは、２～４の整数を表す。）

(In the above general formula (2), B represents an alkyl group, an alkylene group, an aromatic group or a heterocyclic aromatic group having 1 to 20 carbon atoms, which may have a substituent, and n represents an integer of 2 to 4.)

The polyol represented by the general formula (1) is not particularly limited and can be appropriately selected depending on the purpose. For example, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, sorbitol, 1,2,3,6-hexanetetrol, Examples of such compounds include 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, bisphenol A, bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct, hydrogenated bisphenol A, hydrogenated bisphenol A ethylene oxide adduct, and hydrogenated bisphenol A propylene oxide adduct. These compounds may be used alone or in combination of two or more.

The polycarboxylic acid represented by the general formula (2) is not particularly limited and can be appropriately selected depending on the purpose. For example, 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-dodecenylsuccinic acid, isooctylsuccinic acid, isododecenylsuccinic acid, n-dodecylsuccinic acid, isododecylsuccinic acid, n-octenylsuccinic acid, n-octylsuccinic acid, isooctylsuccinic acid, isooctylsuccinic acid, 1,2,4-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, Examples of such carboxylic acids include 1,2,4-naphthalene tricarboxylic acid, 1,2,4-butane tricarboxylic acid, 1,2,5-hexane tricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylene carboxypropane, 1,2,4-cyclohexane tricarboxylic acid, tetra(methylene carboxyl)methane, 1,2,7,8-octane tetracarboxylic acid, pyromellitic acid, empol trimer acid, cyclohexane dicarboxylic acid, cyclohexene dicarboxylic acid, butane tetracarboxylic acid, diphenylsulfone tetracarboxylic acid, ethylene glycol bis(trimellitic acid), etc. These may be used alone or in combination of two or more.

The modified polyester resin is not particularly limited and can be appropriately selected depending on the purpose. For example, it can be a resin obtained by elongation reaction and/or crosslinking reaction of an active hydrogen group-containing compound and a polyester (hereinafter, sometimes referred to as "polyester prepolymer") that can react with the active hydrogen group-containing compound. The elongation reaction and/or crosslinking reaction can be terminated, if necessary, with a reaction terminator (such as a blocked monoamine such as diethylamine, dibutylamine, butylamine, laurylamine, or a ketimine compound).

The active hydrogen group-containing compound acts as an elongation agent, a crosslinking agent, etc. when the polyester prepolymer undergoes an elongation reaction, a crosslinking reaction, etc. in the aqueous phase.
The active hydrogen group-containing compound is not particularly limited as long as it has an active hydrogen group, and can be appropriately selected depending on the purpose. However, when the polyester prepolymer is an isocyanate group-containing polyester prepolymer described later, amines are preferred in that they enable a high molecular weight.
The active hydrogen group is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a hydroxyl group (alcoholic hydroxyl group or phenolic hydroxyl group), an amino group, a carboxyl group, a mercapto group, etc. These may be contained alone or in combination of two or more.
The amines are not particularly limited and can be appropriately selected depending on the purpose. Examples of the amines include diamines, tri- or higher amines, amino alcohols, amino mercaptans, amino acids, and amines obtained by blocking the amino group of these amines.
Examples of the diamine include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4'diaminodiphenylmethane, etc.); alicyclic diamines (4,4'-diamino-3,3'dimethyldicyclohexylmethane, diaminecyclohexane, isophoronediamine, etc.); and aliphatic diamines (ethylenediamine, tetramethylenediamine, hexamethylenediamine, etc.).
Examples of the trivalent or higher polyamines include diethylenetriamine and triethylenetetramine.
Examples of the amino alcohol include ethanolamine and hydroxyethylaniline.
Examples of the amino mercaptan include aminoethyl mercaptan and aminopropyl mercaptan.
Examples of the amino acid include aminopropionic acid and aminocaproic acid.
Examples of the amines with blocked amino groups include ketimine compounds and oxazoline compounds obtained from any of the amines (diamines, trivalent or higher polyamines, amino alcohols, amino mercaptans, amino acids, etc.) and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.). These may be used alone or in combination of two or more. Among these, the amines are preferably diamines or mixtures of diamines and small amounts of trivalent or higher polyamines.

The polymer capable of reacting with the active hydrogen group-containing compound is not particularly limited as long as it has at least a group capable of reacting with the active hydrogen group-containing compound, and can be appropriately selected depending on the purpose. However, in terms of high fluidity and excellent transparency when melted, ease of adjusting the molecular weight of the polymer component, and excellent oil-less low-temperature fixing property and release property in dry toner, urea bond-forming group-containing polyester resin (RMPE) is preferred, and isocyanate group-containing polyester prepolymer is more preferred.

The isocyanate group-containing polyester prepolymer is not particularly limited and can be appropriately selected depending on the purpose. Examples include a polycondensation product of a polyol and a polycarboxylic acid, and a reaction product of an active hydrogen group-containing polyester resin and a polyisocyanate.

The polyol is not particularly limited and can be appropriately selected depending on the purpose. Examples of the polyol include alkylene glycols such as ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, and 1,6-hexanediol; alkylene ether glycols such as diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, and polytetramethylene ether glycol; alicyclic diols such as 1,4-cyclohexanedimethanol and hydrogenated bisphenol A; bisphenols such as bisphenol A, bisphenol F, and bisphenol S. Examples of the polyol include alkylene oxide adducts of the alicyclic diols such as ethylene oxide, propylene oxide, and butylene oxide, diols of alkylene oxide adducts of the bisphenols such as ethylene oxide, propylene oxide, and butylene oxide, polyhydric aliphatic alcohols such as glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, and sorbitol, trihydric or higher phenols such as phenol novolac and cresol novolac, trihydric or higher polyols such as alkylene oxide adducts of trihydric or higher polyphenols, and mixtures of diols and trihydric or higher polyols. These may be used alone or in combination of two or more. Among these, the polyol is preferably the diol alone or a mixture of the diol and a small amount of the trihydric or higher polyol.
The diol is not particularly limited and can be appropriately selected depending on the purpose, but alkylene glycols having 2 to 12 carbon atoms and alkylene oxide adducts of bisphenols (e.g., bisphenol A ethylene oxide 2-mol adduct, bisphenol A propylene oxide 2-mol adduct, bisphenol A propylene oxide 3-mol adduct, etc.) are preferred.

The content of the polyol in the isocyanate group-containing polyester prepolymer is preferably 0.5% by mass or more and 40% by mass or less, more preferably 1% by mass or more and 30% by mass or less, and particularly preferably 2% by mass or more and 20% by mass or less. When the content is 0.5% by mass or more, the occurrence of hot offset can be prevented and both the storage stability and low-temperature fixability of the toner can be achieved, and when the content is 40% by mass or less, excellent low-temperature fixability is obtained.

The polycarboxylic acid is not particularly limited and can be appropriately selected depending on the purpose. Examples of the polycarboxylic acid include alkylene dicarboxylic acids such as succinic acid, adipic acid, and sebacic acid, alkenylene dicarboxylic acids such as maleic acid and fumaric acid, aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, and naphthalene dicarboxylic acid, and polycarboxylic acids having three or more valences (aromatic polycarboxylic acids having 9 to 20 carbon atoms such as trimellitic acid and pyromellitic acid). These may be used alone or in combination of two or more. Among these, the polycarboxylic acid is preferably an alkenylene dicarboxylic acid having 4 to 20 carbon atoms or an aromatic dicarboxylic acid having 8 to 20 carbon atoms. Instead of the polycarboxylic acid, anhydrides of polycarboxylic acids, lower alkyl esters (methyl esters, ethyl esters, isopropyl esters, etc.), and the like may be used.

The mixing ratio of the polyol and the polycarboxylic acid is not particularly limited and can be appropriately selected depending on the purpose. The equivalent ratio [OH]/[COOH] of the hydroxyl group [OH] of the polyol to the carboxyl group [COOH] of the polycarboxylic acid is preferably 2/1 to 1/1, more preferably 1.5/1 to 1/1, and particularly preferably 1.3/1 to 1.02/1.

The polyisocyanate is not particularly limited and can be appropriately selected depending on the purpose. For example, aliphatic polyisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethyl caproate, octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, tetradecamethylene diisocyanate, trimethylhexane diisocyanate, and tetramethylhexane diisocyanate, alicyclic polyisocyanates such as isophorone diisocyanate and cyclohexylmethane diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, and the like can be used. Examples of such isocyanates include aromatic diisocyanates such as 1,5-naphthylene diisocyanate, diphenylene-4,4'-diisocyanate, 4,4'-diisocyanato-3,3'-dimethyldiphenyl, 3-methyldiphenylmethane-4,4'-diisocyanate, and diphenylether-4,4'-diisocyanate; aromatic aliphatic diisocyanates such as α,α,α',α'-tetramethylxylylene diisocyanate; isocyanates such as tris-isocyanatoalkyl-isocyanate and triisocyanatocycloalkyl-isocyanate; and those blocked with phenol derivatives, oximes, caprolactam, etc. These may be used alone or in combination of two or more.

The mixing ratio of the polyisocyanate and the active hydrogen group-containing polyester resin (hydroxyl group-containing polyester resin) is not particularly limited and can be appropriately selected depending on the purpose. The equivalent ratio [NCO]/[OH] of the isocyanate group [NCO] of the polyisocyanate to the hydroxyl group [OH] of the hydroxyl group-containing polyester resin is preferably 5/1 to 1/1, more preferably 4/1 to 1.2/1, and particularly preferably 3/1 to 1.5/1. When the equivalent ratio [NCO]/[OH] is 1/1 or more, excellent offset resistance is obtained, and when it is 5/1 or less, excellent low-temperature fixability is obtained.

The content of the polyisocyanate in the isocyanate group-containing polyester prepolymer is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.5% by mass or more and 40% by mass or less, more preferably 1% by mass or more and 30% by mass or less, and particularly preferably 2% by mass or more and 20% by mass or less. When the content is 0.5% by mass or more, the toner has excellent hot offset resistance and can achieve both storage stability and low-temperature fixability, and when the content is 40% by mass or less, the toner has excellent low-temperature fixability.

The average number of isocyanate groups contained per molecule of the isocyanate group-containing polyester prepolymer is preferably 1 or more, more preferably 1.2 to 5, and even more preferably 1.5 to 4. When the average number is 1 or more, the molecular weight of the polyester resin (RMPE) modified with the urea bond-forming group becomes high, and the polyester resin has excellent hot offset resistance.

The mixing ratio of the isocyanate group-containing polyester prepolymer and the amines is not particularly limited and can be appropriately selected depending on the purpose. The mixing equivalent ratio [NCO]/[NHx] of the isocyanate group [NCO] in the isocyanate group-containing polyester prepolymer and the amino group [NHx] in the amines is preferably 1/3 or more and 3/1 or less, more preferably 1/2 or more and 2/1 or less, and particularly preferably 1/1.5 or more and 1.5/1 or less. When the mixing equivalent ratio ([NCO]/[NHx]) is 1/3 or more, the low-temperature fixing property is excellent, and when the mixing equivalent ratio ([NCO]/[NHx]) is 3/1 or less, the molecular weight of the urea-modified polyester resin is high and the hot offset resistance is excellent.

The weight average molecular weight (Mw) of the polymer capable of reacting with the active hydrogen group-containing compound is not particularly limited and can be appropriately selected depending on the purpose, but the molecular weight distribution of the tetrahydrofuran (THF) soluble portion by GPC (gel permeation chromatography) is preferably 3,000 to 40,000, more preferably 4,000 to 30,000. When the weight average molecular weight (Mw) is 3,000 or more, the storage stability is good, and when the weight average molecular weight (Mw) is 40,000 or less, the low-temperature fixability is excellent.

The weight average molecular weight (Mw) can be measured, for example, as follows. First, a column is stabilized in a heat chamber at 40° C., tetrahydrofuran (THF) is passed as a column solvent at this temperature at a flow rate of 1 mL per minute, and 50 μL to 200 μL of a tetrahydrofuran sample solution of the resin, the sample concentration of which is adjusted to 0.05 to 0.6 mass %, is injected and measured. In measuring the molecular weight of a sample, the molecular weight distribution of the sample is calculated from the relationship between the logarithm of a calibration curve prepared using several types of monodisperse polystyrene standard samples and the count number. As the standard polystyrene sample for preparing the calibration curve, the polystyrene standard sample manufactured by Pressure Chemical Co., Ltd. Alternatively, it is preferable to use at least about 10 standard polystyrene samples manufactured by Toyo Soda Kogyo Co., Ltd., each having a molecular weight of ⁶ ×10, 2.1× ¹⁰ , 4× ¹⁰ , 1.75× ¹⁰ , 1.1×10, 3.9× ¹⁰ , 8.6× ¹⁰ , 2× ¹⁰ , and 4.48× ¹⁰ . As a detector, an RI (refractive index) detector can be used.

The crystalline polyester can be used to improve the low-temperature fixability of colored resin particles. The crystalline polyester has crystallinity and therefore exhibits a thermal melting property that shows a rapid viscosity drop near the fixing start temperature. In other words, the heat-resistant storage stability due to the crystallinity is good up to just before the melting start temperature, and at the melting start temperature, a rapid viscosity drop (sharp melt property) occurs and the toner is fixed, so that a toner having both good heat-resistant storage stability and low-temperature fixability can be designed, and good results are also shown in terms of the release width (the difference between the minimum fixing temperature and the maximum fixing temperature).
The crystalline polyester is synthesized from an alcohol component and an acid component and is not particularly limited and may be appropriately selected depending on the purpose, but a compound having a structure represented by the following general formula (1) is preferred.
[-O-CO-(CR1=CR2)l-CO-O-(CH2)n-]m (1) ... general formula (1)
(wherein n and m are the numbers of repeating units; L is an integer from 1 to 3; R1 and R2 are hydrogen atoms or hydrocarbon groups, and may be the same or different.)
Examples of the alcohol component include diol compounds having 2 to 6 carbon atoms, such as 1,4-butanediol and 1,6-hexanediol, and derivatives thereof. The content of the alcohol component is preferably 80 mol % or more, and more preferably 85 mol % or more and 100 mol % or less.
Examples of the acid component include fumaric acid, a carboxylic acid having a double bond (C=C bond), and derivatives thereof.

Methods for controlling the crystallinity and softening point of the crystalline polyester include using a nonlinear polyester that is condensed by adding a polyhydric alcohol having a valence of three or more, such as glycerin, as the alcohol component during polyester synthesis, or a polycarboxylic acid having a valence of three or more, such as trimellitic anhydride, as the acid component.

The molecular structure of the crystalline polyester can be confirmed by NMR measurement of a solution or solid, as well as X-ray diffraction, GC/MS, LC/MS, IR measurement, etc., but a simple example is one having an absorption due to olefin δCH (out-of-plane bending vibration) at 965±10 cm ⁻¹ or 990±10 cm ⁻¹ in an infrared absorption spectrum.

From the viewpoint that a molecular weight distribution that is sharp and low molecular weight as described above provides excellent low-temperature fixability, the molecular weight of the crystalline polyester is preferably such that the molecular weight distribution of the o-dichlorobenzene soluble portion by GPC has a peak position of 3.5 to 4.0 in a molecular weight distribution diagram with the horizontal axis being log (M) and the vertical axis being weight %, the half-width of the peak is 1.5 or less, the weight average molecular weight (Mw) is 1,000 to 30,000, the number average molecular weight (Mn) is 500 to 6,000, and Mw/Mn is 2 to 8.

The melting temperature and 1/2 outflow temperature (F1/2 temperature) of the crystalline polyester are desirably low as long as the heat-resistant storage stability is not deteriorated, and preferably the DSC endothermic peak temperature is 50 to 150°C. If the melting temperature and F1/2 temperature are 50°C or lower, the heat-resistant storage stability will deteriorate and blocking will be more likely to occur due to the temperature inside the developing device, and if they are 130°C or higher, the minimum fixing temperature will be high and low-temperature fixing properties will not be obtained.

From the viewpoint of affinity between paper and resin, the acid value of the crystalline polyester is preferably 5 mgKOH/g or more, more preferably 10 mgKOH/g or more, in order to achieve the desired low-temperature fixability, while it is preferably 45 mgKOH/g or less in order to improve hot offset properties. Furthermore, the hydroxyl value of the crystalline polymer is preferably 0 to 50 mgKOH/g, more preferably 5 to 50 mgKOH/g, in order to achieve the desired low-temperature fixability and good charging properties.

<Coloring Agent>
As the colorant, known dyes and pigments can be used, for example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, yellow ochre, yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR), permanent yellow (NCG), Balkan fast yellow (5G, R), tartrazine lake, quinoline yellow lake, anthrazan yellow BGL, isoindolinone yellow, red iron oxide, red lead, vermilion lead. , Cadmium Red, Cadmium Mercury Red, Antimony Vermilion, Permanent Red 4R, Para Red, Faise Red, Parachlor Orthonitroaniline Red, Lithol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belcan Fast Rubin B, Brilliant Scarlet G, Lithol Rubin GX, Permanent Red F5R, Brilliant Carmine 6B, Pogment Scarlet 3B, Bordeaux 5B, Toluidine Malt Red, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thioindigo Red B, Thioindigo Maroon, Oil Red, Quinacridone Red, Pyrazolone Red, Polyazo Red, Chrome Vermilion, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal-free Phthalocyanine Blue, Phthalocyanine Blue , fast sky blue, indanthrene blue (RS, BC), indigo, ultramarine blue, Prussian blue, anthraquinone blue, fast violet B, methyl violet lake, cobalt purple, manganese purple, dioxane violet, anthraquinone violet, chrome green, zinc green, chromium oxide, pyridian, emerald green, pigment green B, naphthol green B, green gold, acid green lake, malachite green lake, phthalocyanine green, anthraquinone green, titanium oxide, zinc oxide, lithopone and mixtures thereof can be used.

The colorant can also be used as a masterbatch composited with a binder resin. Examples of binder resins used in the manufacture of a masterbatch or for kneading with a masterbatch include, in addition to the binder resins and modified resins listed above, polymers of styrene and its substitutes, such as polystyrene, poly-p-chlorostyrene, and polyvinyltoluene; styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethyl ... Styrene-based copolymers such as styrene-acrylonitrile copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, and styrene-maleic acid ester copolymer; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, and paraffin wax can be used alone or in combination.

In the method of producing the master batch, the resin for the master batch and the colorant are mixed and kneaded under high shear force to obtain the master batch. In this case, an organic solvent can be used to enhance the interaction between the colorant and the resin. In addition, a method called the flushing method, in which an aqueous paste containing water for the colorant is mixed and kneaded with the resin and organic solvent, the colorant is transferred to the resin side, and the water and organic solvent components are removed, is also preferably used because it does not require drying since the wet cake of the colorant can be used as is. A high shear dispersion device such as a three-roll mill is preferably used for mixing and kneading.

-Other ingredients-
The other components are not particularly limited as long as they are contained in ordinary toners and can be appropriately selected depending on the purpose. Examples of the other components include organic solvents and charge control agents.

-Organic solvent-
The organic solvent is preferably volatile, with a boiling point of less than 100° C., from the viewpoint of facilitating subsequent removal of the solvent. Examples of such organic solvents include toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, methyl ethyl ketone, and methyl isobutyl ketone, which can be used alone or in combination of two or more.
When the resin to be dissolved or dispersed in an organic solvent is a resin having a polyester skeleton, it is preferable to use an ester-based solvent such as methyl acetate, ethyl acetate, or butyl acetate, or a ketone-based solvent such as methyl ethyl ketone or methyl isobutyl ketone, in order to obtain high solubility. Among these, methyl acetate, ethyl acetate, and methyl ethyl ketone, which have high solvent removability, are particularly preferable.

Examples of the surfactant include anionic surfactants such as alkylbenzenesulfonates, α-olefinsulfonates, and phosphate esters; amine salt-type surfactants such as alkylamine salts, aminoalcohol fatty acid derivatives, polyamine fatty acid derivatives, and imidazolines; cationic surfactants of quaternary ammonium salt-type surfactants such as alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, pyridinium salts, alkylisoquinolinium salts, and benzethonium chloride; nonionic surfactants such as fatty acid amide derivatives and polyhydric alcohol derivatives; and amphoteric surfactants such as alanine, dodecyldi(aminoethyl)glycine, di(octylaminoethyl)glycine, and N-alkyl-N,N-dimethylammonium betaine. In addition, by using a surfactant having a fluoroalkyl group, the effect can be achieved with a very small amount.

Examples of the anionic surfactant having a fluoroalkyl group include fluoroalkyl carboxylic acids having 2 to 10 carbon atoms, disodium perfluorooctanesulfonyl glutamate, sodium 3-[ω-fluoroalkyl(C6 to C11)oxy]-1-alkyl(C3 to C4)sulfonate, sodium 3-[ω-fluoroalkanoyl(C6 to C8)-N-ethylamino]-1-propanesulfonate, fluoroalkyl(C11 to C20)carboxylic acids, perfluoroalkyl carboxylic acids (C7 to C13), perfluoroalkyl(C4 to C12)sulfonic acids, perfluorooctanesulfonic acid diethanolamide, N-propyl-N-(2-hydroxyethyl)perfluorooctanesulfonamide, perfluoroalkyl(C6 to C10)sulfonamidopropyltrimethylammonium salts, perfluoroalkyl(C6 to C10)-N-ethylsulfonylglycine salts, monoperfluoroalkyl(C6 to C16)ethyl phosphate esters, and metal salts thereof.
Examples of the cationic surfactant include aliphatic primary, secondary or secondary amine acids having a fluoroalkyl group, aliphatic quaternary ammonium salts such as perfluoroalkyl (C6 to C10)sulfonamidopropyltrimethylammonium salts, benzalkonium salts, benzethonium chloride, pyridinium salts, and imidazolinium salts.

The resin fine particles contained in the aqueous medium can be added as an emulsifier to the aqueous medium before the formation of toner particles, thereby suppressing the coalescence of oil droplets and improving granulation properties.
The resin fine particles contained in the aqueous medium are not particularly limited as long as they are resins capable of forming an aqueous dispersion, and can be appropriately selected according to purpose, and examples thereof include vinyl resins, polyurethane resins, epoxy resins, polyester resins, polyamide resins, polyimide resins, silicon resins, phenol resins, melamine resins, urea resins, aniline resins, ionomer resins, polycarbonate resins, etc. These may be used alone or in combination of two or more. Among these, vinyl resins, polyurethane resins, epoxy resins, and polyester resins are preferred because they are easy to obtain an aqueous dispersion of resin particles.
The vinyl resin is a polymer obtained by homopolymerizing or copolymerizing a vinyl monomer, and examples thereof include a styrene-(meth)acrylic acid ester copolymer, a styrene-butadiene copolymer, a (meth)acrylic acid-acrylic acid ester polymer, a styrene-acrylonitrile copolymer, a styrene-maleic anhydride copolymer, and a styrene-(meth)acrylic acid copolymer.

-Charge control agent-
The charge control agent may be any known agent, such as nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdic acid chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (including fluorine-modified quaternary ammonium salts), alkylamides, phosphorus simple substance or compounds, tungsten simple substance or compounds, fluorine-based activators, metal salicylate, and metal salts of salicylic acid derivatives.
Specifically, the nigrosine dye Bontron 03, the quaternary ammonium salt Bontron P-51, the metal-containing azo dye Bontron S-34, the oxynaphthoic acid metal complex E-82, the salicylic acid metal complex E-84, the phenol condensate E-89 (all manufactured by Orient Chemical Industry Co., Ltd.), the quaternary ammonium salt molybdenum complexes TP-302 and TP-415 (all manufactured by Hodogaya Chemical Co., Ltd.), the quaternary ammonium salt Copy Charge PSYVP2038, the triphenylmethane derivative Copy Blue PR, and the quaternary ammonium salt Copy Charge NEG. Examples of the pigments include VP2036, Copy Charge NXVP434 (all manufactured by Hoechst), LRA-901, boron complex LR-147 (manufactured by Nippon Carlit Co., Ltd.), copper phthalocyanine, perylene, quinacridone, azo pigments, and polymeric compounds having functional groups such as sulfonic acid groups, carboxyl groups, and quaternary ammonium salts.

(Toner Manufacturing Method)
The method for producing the toner includes an oil phase preparation step, an emulsification step, a solvent removal step, and an aging step, and further includes other steps as necessary.

<Oil phase preparation process>
The oil phase preparation step is a step of gradually adding and dispersing a binder resin, a release agent, a colorant, etc., into an organic solvent while stirring. It is preferable to reduce the particle size of the release agent, the colorant, etc., before adding to the organic solvent. By reducing the particle size of the release agent, the release agent is easily encapsulated inside the toner, and the amount of the release agent exposed to the toner surface is reduced. A known dispersing machine such as a bead mill or a disk mill can be used for the dispersion. When performing additional dispersion, the dispersion efficiency of the release agent particles can be improved and the particle size can be further reduced by adding the dispersion assistant.

<Emulsification process>
The emulsification step is a step of dispersing the oil phase in an aqueous medium containing at least a surfactant to prepare a dispersion liquid in which toner particles made of the oil phase are dispersed. The emulsification step is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a low-speed shear type, a high-speed shear type, a friction type, a high-pressure jet type, and an ultrasonic wave type. Among these, the high-speed shear type is preferred because it can adjust the particle size of the dispersion to 2 μm to 20 μm.
When a high-speed shear type dispersing machine is used, the rotation speed is not particularly limited, but is preferably 1,000 rpm to 30,000 rpm, and more preferably 5,000 rpm to 15,000 rpm.

<Desolvation process>
The solvent removal step may, for example, be a step of stirring the obtained dispersion liquid to remove the organic solvent. It is preferable to gradually increase the temperature of the dispersion liquid while stirring it, and to completely evaporate and remove the organic solvent.
The solvent removal step may be, for example, a method in which the dispersion is stirred at 15° C. to 45° C. for 0.5 to 2.0 hours to make the concentration of the organic solvent in the dispersion 15% by mass or less. This allows the organic solvent to be removed in a short time, and allows the portions where the removed organic solvent was present to form pores on the surface of the toner without being blocked by the surrounding binder resin. The concentration of the organic solvent can be measured using a gas chromatograph (GC-2010, manufactured by Shimadzu Corporation) or the like.
In addition, in the solvent removal step, the obtained colored resin dispersion may be sprayed in a dry atmosphere while being stirred to completely remove the organic solvent in the droplets. The colored resin dispersion may be depressurized while being stirred to evaporate and remove the organic solvent.
The drying atmosphere in which the emulsified dispersion is sprayed is generally air, nitrogen, carbon dioxide, a gas obtained by heating combustion gas, etc., and in particular, various air streams heated to a temperature equal to or higher than the boiling point of the highest boiling point solvent used. The desired quality can be obtained sufficiently by short-term treatment with a spray dryer, belt dryer, rotary kiln, etc.

<Aging process>
When a modified resin having an isocyanate group at the end is added, an aging step may be carried out to promote the elongation and crosslinking reaction of the isocyanate. The aging time is usually 10 minutes to 30 hours, preferably 2 to 15 hours. The reaction temperature is usually 20 to 65°C, preferably 35 to 50°C.

<Other processes>
The other steps are not particularly limited and can be appropriately selected depending on the purpose. Examples of the other steps include a washing step, a drying step, and an external additive treatment step.

The volume average particle diameter (Dv) of the toner base particles is preferably 3.0 μm or more and 6.0 μm or less. When the volume average particle diameter (Dv) is 3.0 μm, when a one-component developer is used, the toner can be prevented from fusing to members such as a developing roller or a blade, and when a two-component developer is used, the carrier's charging ability can be prevented from being reduced due to the toner fusing to the carrier surface. When the volume average particle diameter (Dv) is 6.0 μm or less, a high-resolution, high-quality image can be obtained.
The ratio (Dv/Dn) of the volume average particle diameter (Dv) of the toner base particles to the number average particle diameter (Dn) of the toner base particles is preferably 1.05 or more and 1.25 or less. When the ratio (Dv/Dn) is 1.25 or less, a high-resolution, high-quality image can be obtained. In addition, when the ratio (Dv/Dn) is 1.05 or more, the charging property and cleaning property of the toner are good.

The toner storage unit in the present invention refers to a unit having a function of storing toner and storing the toner. Examples of the toner storage unit include a toner storage container, a developing unit, and a process cartridge.
The toner storage container refers to a container that stores toner.
The developing device has a means for containing toner and developing the toner.
The process cartridge is a cartridge which integrates at least an image carrier and a developing means, contains toner, and is detachably mountable to an image forming apparatus. The process cartridge may further include at least one selected from a charging means, an exposure means, and a cleaning means.

The following describes examples of the present invention, but the present invention is not limited to these examples.

(Production Example of Resin Particle Dispersion)
In a reaction vessel equipped with a stirring rod and a thermometer, 683 parts by mass of water, 11 parts by mass of sodium salt of methacrylic acid ethylene oxide adduct sulfate (Eleminol RS-30, manufactured by Sanyo Chemical Industries), 5 parts by mass of sodium salt of dodecanol ethylene oxide adduct sulfate (Calipon EN-200, manufactured by Sanyo Chemical Industries), 83 parts by mass of styrene, 83 parts by mass of methacrylic acid, 110 parts by mass of butyl acrylate, and 1 part by mass of ammonium persulfate were charged and stirred at 400 rpm for 15 minutes to obtain a white emulsion. The mixture was heated to a temperature of 75°C and reacted for 2 hours. Furthermore, 30 parts by mass of a 1% aqueous ammonium persulfate solution was added dropwise, and the mixture was aged at 75°C for 8 hours to obtain a resin fine particle dispersion with a solid content of 20%. The volume average particle size was 38 nm.

(Production Example of Low Molecular Weight Polyester Resin)
In a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen inlet tube, 220 parts by mass of bisphenol A ethylene oxide 2 mole adduct, 561 parts by mass of bisphenol A propylene oxide 3 mole adduct, 218 parts by mass of terephthalic acid, 48 parts by mass of adipic acid, and 2 parts by mass of dibutyltin oxide were placed and reacted for 8 hours at normal pressure and 230° C. Next, after reacting for 5 hours under a reduced pressure of 10 mmHg to 15 mmHg, 45 parts by mass of trimellitic anhydride was placed in the reaction vessel and reacted for 2 hours at normal pressure and 180° C. to obtain a low molecular weight polyester resin.
The obtained low molecular weight polyester resin had a number average molecular weight of 2,500, a weight average molecular weight of 6,700, a glass transition temperature (Tg) of 43° C., and an acid value of 25 mgKOH/g.

(Production Example 1 of Release Agent Dispersion)
12.2 parts by mass of ester wax (LW-13, manufactured by Sanyo Chemical Industries, Ltd.), 8.5 parts by mass of dispersant (styrene acrylic, manufactured by Sanyo Chemical Industries, Ltd.), 36.6 parts by mass of the low molecular weight polyester resin, and 81.0 parts by mass of ethyl acetate were mixed at 60 ° C. for 3 hours, and then cooled to 30 ° C. or less with an external heat exchanger to obtain a mixture. Next, 3.7 parts by mass of dispersant (styrene acrylic, manufactured by Sanyo Chemical Industries, Ltd.) was added to the obtained mixture and mixed for 0.5 hours, and the mixture was circulated and dispersed using a bead mill device (LMZ60, manufactured by Ashizawa Finetech Co., Ltd.) to obtain a release agent dispersion 1. Zirconia beads with a bead diameter of 0.5 mm were used as the media.

(Production Example 2 of Release Agent Dispersion)
A release agent dispersion 2 was obtained in the same manner as in Production Example 1 of the release agent dispersion, except that in Production Example 1 of the release agent dispersion, the content of the dispersant (styrene acrylic, manufactured by Sanyo Chemical Industries, Ltd.) was changed to 7.3 parts by mass, and no dispersant (styrene acrylic, manufactured by Sanyo Chemical Industries, Ltd.) was added to the obtained mixture.

(Production Example of Crystalline Polyester Dispersion)
In a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen inlet tube, 2,070 parts by mass of 1,4-butanediol, 2,535 parts by mass of fumaric acid, 291 parts by mass of trimellitic anhydride, and 4.9 parts by mass of hydroquinone were placed and reacted at 160° C. for 5 hours, and then the temperature was raised to 200° C. and reacted for 1 hour. Thereafter, the mixture was reacted at 8.3 kPa for 1 hour to obtain a crystalline polyester resin.
36% by weight of the obtained crystalline polyester resin was dissolved in ethyl acetate at 55°C for 1 hour. Then, the mixture was cooled to 20°C or less using an external heat exchanger using cooling water, and the crystalline polyester resin was precipitated to obtain a crystallized liquid. The obtained crystallized liquid was circulated and pulverized using a bead mill device (LMZ25, manufactured by Ashizawa Finetech) to obtain a crystalline polyester resin dispersion. Zirconia beads with a bead diameter of 0.5 mm were used as the media.

Example 1
- Preparation of oil phase -
In a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen inlet tube, 795 parts by mass of bisphenol A ethylene oxide 2 mole adduct, 200 parts by mass of isophthalic acid, 65 parts by mass of terephthalic acid, and 2 parts by mass of dibutyltin oxide were respectively charged and subjected to a condensation reaction at 210°C for 8 hours under normal pressure nitrogen gas flow. Next, the mixture was reacted for 5 hours while being dehydrated under a reduced pressure of 10 mmHg to 15 mmHg, and then cooled to 80°C, followed by reaction with 170 parts by mass of isophorone diisocyanate in ethyl acetate for 2 hours to obtain a prepolymer. The weight average molecular weight of the obtained prepolymer was 5,000.
307 parts by mass of the release agent dispersion 1, 212 parts by mass of the low molecular weight polyester solution, 26 parts by mass of black pigment C-60, 78 parts by mass of the crystalline polyester dispersion, and 22 parts by mass of ethyl acetate were charged into a tank, and the mixture was dissolved and dispersed for 3 hours to obtain a mixed liquid.
Next, 395 parts by mass of the mixture, 51 parts by mass of prepolymer, and 3.5 parts by mass of a 50% by mass solution of isophoronediamine in ethyl acetate were mixed and stirred at 5,000 rpm with a TK homomixer (manufactured by Tokushu Kika Co., Ltd.) to uniformly dissolve and disperse the mixture, thereby obtaining an oil phase.

- Preparation of aqueous phase -
1,180 parts by mass of water, 51 parts by mass of the resin fine particle dispersion, 262 parts by mass of a 50% by weight aqueous solution of sodium dodecyldiphenyletherdisulfonate (Eleminol MON-7, manufactured by Sanyo Chemical Industries, Ltd.), and 138 parts by mass of ethyl acetate were added, mixed and stirred to obtain an aqueous phase.

- Emulsion -
Next, 550 parts by mass of the aqueous phase was placed in another container equipped with a stirrer and a thermometer, and 450 parts by mass of the oil phase was added while stirring at 11,000 rpm with a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), and mixed for 1 minute to obtain an emulsified slurry.

- Removal and aging -
The obtained emulsified slurry was stored in a SUS tank equipped with a hot water jacket and a vacuum line, and the pressure was gradually reduced while stirring at a peripheral speed of the stirring blade at the outer periphery end of 10.5 m/sec, and the solvent was removed at a final reduced pressure of -95 kPa. During this process, the reduced pressure conditions were adjusted so that the organic solvent concentration in the emulsified slurry would change over time as follows. The organic solvent concentration in the emulsified slurry was determined by measurement using gas chromatography (GC-2010, manufactured by Shimadzu Corporation).
STEP 1: The solvent was removed for 40 minutes at a slurry temperature of 30° C., and the organic solvent concentration was adjusted to 15% by mass.
STEP 2: The solvent was removed for 80 minutes at a slurry temperature of 30° C., and the organic solvent concentration was adjusted to 5% by mass.
STEP 3: The solvent was removed for 180 minutes while increasing the slurry temperature to 36° C., and the organic solvent concentration became 0.1% by mass.
Thereafter, aging was carried out at 50° C. for 4 hours to obtain a dispersed slurry.

- Cleaning and drying process -
The dispersed slurry was pressure filtered to obtain a filter cake, which was then subjected to the following treatment.
(1) 100 parts by mass of ion-exchanged water was added, and the mixture was mixed with a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) (at a rotation speed of 6,000 rpm for 5 minutes), and then filtered.
(2) 100 parts by mass of ion-exchanged water was added and mixed with a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) (at a rotation speed of 6,000 rpm for 5 minutes), and then 1% by mass hydrochloric acid was added with stirring until the pH reached about 5.0, and the mixture was stirred for 1 hour and then filtered.
(3) 300 parts by mass of ion-exchanged water was added, and the mixture was mixed with a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) (at a rotation speed of 6,000 rpm for 5 minutes), and then filtered twice.
The obtained filter cake was dried in a circulating air dryer at 40° C. for 48 hours, and then sieved through a 75 μm mesh to prepare toner base particles 1.

-mixture-
100 parts by weight of the toner base particles and 1.5 parts by weight of hydrophobic silica (HDK-2000, manufactured by Wacker Chemie KK) were mixed for 5 minutes at a peripheral speed of 33 m/s in a 20 L Henschel mixer (manufactured by Mitsui Mining Co., Ltd.), and the mixture was classified using a 500 mesh sieve to obtain a toner.

Example 2
A toner was obtained in the same manner as in Example 1, except that the amount of the release agent dispersion in the preparation of the oil phase was changed to 361 parts by mass.

Example 3
A toner was obtained in the same manner as in Example 1, except that in the preparation of the oil phase, the release agent dispersion liquid was changed to 253 parts by mass, the mixed liquid was changed to 383 parts by mass, and the prepolymer was changed to 64 parts by mass, STEP 1 of the dissolving and aging was changed to removing the solvent for 100 minutes at a slurry temperature of 24° C. and setting the organic solvent concentration to 15% by mass, STEP 2 was changed to removing the solvent for 80 minutes at a slurry temperature of 24° C. and setting the organic solvent concentration to 5% by mass, and STEP 3 was changed to removing the solvent for 180 minutes at a slurry temperature of 36° C. and setting the organic solvent concentration to 0.1% by mass, and aging was performed at 45° C. for 4 hours.

Example 4
A toner was obtained in the same manner as in Example 3, except that in STEP 1 of the solvent removal and aging, the solvent was removed for 80 minutes at a slurry temperature of 30° C. and the organic solvent concentration was 15% by mass.

Example 5
A toner was obtained in the same manner as in Example 3, except that in STEP 1 of the solvent removal and aging, the solvent was removed for 40 minutes at a slurry temperature of 30° C. and the organic solvent concentration was 15% by mass.

(Example 6)
A toner was obtained in the same manner as in Example 3, except that in STEP 1 of the solvent removal and aging, the solvent was removed for 40 minutes at a slurry temperature of 30° C., and the organic solvent concentration was set to 15% by mass, and in STEP 2, the solvent was removed for 80 minutes at a slurry temperature of 30° C., and the organic solvent concentration was set to 5% by mass.

(Example 7)
A toner was obtained in the same manner as in Example 3, except that STEP 1 of the solvent removal and aging was changed to removing the solvent for 40 minutes at a slurry temperature of 36° C. and the organic solvent concentration was set to 15% by mass, STEP 2 was changed to removing the solvent for 80 minutes at a slurry temperature of 36° C. and the organic solvent concentration was set to 5% by mass, and STEP 3 was changed to removing the solvent for 180 minutes at a slurry temperature of 36° C. and the organic solvent concentration was set to 0.1% by mass.

(Example 8)
A toner was obtained in the same manner as in Example 1, except that in Example 1, the release agent dispersion liquid in the preparation of the oil phase was changed to 253 parts by mass, and in STEP 1 of the dissolving and aging, the solvent was removed for 160 minutes at a slurry temperature of 24° C. and the organic solvent concentration was set to 15% by mass, and in STEP 2, the solvent was removed for 80 minutes at a slurry temperature of 24° C. and the organic solvent concentration was set to 5% by mass, and aging was performed at 45° C.

Example 9
A toner was obtained in the same manner as in Example 8, except that aging was carried out at 50°C.

Example 10
A toner was obtained in the same manner as in Example 9, except that in Example 1, the mixed liquid for preparing the oil phase was changed to 404 parts by mass, and the prepolymer was changed to 43 parts by mass.

(Example 11)
A toner was obtained in the same manner as in Example 1, except that the amount of the release agent dispersion in the preparation of the oil phase was changed to 253 parts by mass.

Example 12
A toner was obtained in the same manner as in Example 7, except that the amount of the release agent dispersion in the preparation of the oil phase was changed to 361 parts by mass.

(Example 13)
A toner was obtained in the same manner as in Example 10, except that the amount of the release agent dispersion in the preparation of the oil phase was changed to 361 parts by mass.

(Comparative Example 1)
A toner was obtained in the same manner as in Example 8, except that the release agent dispersion 1 in the preparation of the oil phase was changed to the release agent dispersion 2, the mixed liquid was changed to 383 parts by mass, and the prepolymer was changed to 64 parts by mass.

(Comparative Example 2)
A toner was obtained in the same manner as in Example 8, except that the amounts of the release agent dispersion liquid, the mixed liquid, and the prepolymer used in preparing the oil phase were changed to 145 parts by weight, 383 parts by weight, and 64 parts by weight, respectively.

(Comparative Example 3)
A toner was obtained in the same manner as in Example 1, except that the amount of the release agent dispersion in the preparation of the oil phase was changed to 434 parts by mass.

(Comparative Example 4)
A toner was obtained in the same manner as in Example 1, except that in Example 3, the amount of the release agent dispersion liquid in the preparation of the oil phase was changed to 217 parts by mass.

Next, each toner was evaluated for "filming," "hot offset resistance," "low-temperature fixability," and "uneven gloss" as follows. The results are shown in Table 1.

(Filming)
Using a copying machine (MP9001) manufactured by Ricoh Co., Ltd., 100 sheets were printed continuously 50 times, and filming was evaluated based on the following evaluation criteria.
◯: No filming occurs △: Slight filming occurs ×: A lot of filming occurs

(Hot offset resistance)
A copy test was conducted by setting Ricoh Type 6200 paper in a modified Ricoh MF2200 copier that uses a Teflon (registered trademark) roller as the fixing roller. The fixing temperature was changed to determine the temperature at which hot offset occurs (upper fixing temperature limit), and the hot offset resistance was evaluated based on the following evaluation criteria. The evaluation conditions were set as follows: paper feed linear speed 50 mm/sec, surface pressure 2.0 kgf/ ^cm2 , nip width 4.5 mm.
◎: The upper limit fixing temperature is 195°C or higher. ◯: The upper limit fixing temperature is 190°C or higher and lower than 195°C. △: The upper limit fixing temperature is 180°C or higher and lower than 190°C. ×: The upper limit fixing temperature is lower than 180°C.

(Low temperature fixability)
A thick paper (copy printing paper <135>; NBS Ricoh) was set in an image forming apparatus ("IPSIO Color 8100"; Ricoh) modified to an oil-less fixing method, and a fixed image was obtained by adjusting the toner density so that 1.0±0.1 mg/ ^cm2 of toner was developed in a solid image. The fixing roll temperature (lower limit fixing temperature) at which the remaining rate of the image after rubbing the resulting fixed image with a pad was 70% was determined, and the low-temperature fixing property was evaluated based on the following evaluation criteria.
◎: The minimum fixing temperature is less than 120°C. ◯: The minimum fixing temperature is 120°C or more and less than 135°C. △: The minimum fixing temperature is 135°C or more and less than 150°C. ×: The minimum fixing temperature is 150°C or more.

(Uneven gloss)
Using a Ricoh Co., Ltd. copy machine (MP9001), the first image and the second solid image of the evaluation chart (FIG. 1) were successively formed on Mondi Color Copy 300 (basis weight: 300 g/m ² ) manufactured by Mondi, so that the toner adhesion amount was 1.00±0.03 mg/cm ² . The paper was fed at a linear speed of 400 mm/sec, a surface pressure of 1.6 kgf/cm 2 , and a nip width of 15 mm, and the fixing temperature was changed to perform fixing. The second fixed image at each fixing temperature was used as an evaluation image for "uneven gloss". The evaluation of uneven gloss was performed by measuring the 60 degree gloss at three arbitrary points of the evaluation sites (1) and (2) of the evaluation image using a gloss meter VG-7000 (manufactured by Nippon Denshoku Industries Co., Ltd.), calculating the average gloss of each, calculating the fixing temperature at which the gloss difference between these was 20% or more, and evaluating the uneven gloss based on the following evaluation criteria.
◯: The fixing temperature is 180° C. or higher, or the gloss difference is not 20% or higher. △: The fixing temperature is 170° C. or higher and less than 180° C. ×: The fixing temperature is less than 170° C.

(comprehensive evaluation)
The evaluation results of "filming,""offsetresistance,""low-temperaturefixability," and "uneven gloss" were evaluated according to the following criteria.
◎: 1 or more ◎ and 0 △ and 0 × 〇: 1 or more △ and 0 × or 4 〇 ×: 1 or more ×

For example, aspects of the present invention are as follows.
<1> A toner containing at least a binder resin and a release agent,
The amount of the release agent extracted with hexane is 31 mg/g or more and 95 mg/g or less,
The toner is characterized in that the intensity ratio (P2850/P828) of the peak (P2850) derived from the release agent to the peak (P828) derived from the binder resin, which is determined by FTIR-ATR (attenuated total reflection infrared spectroscopy) at 25° C., is 0.05 or less.
<2> The toner according to <1>, wherein an extractable amount of the release agent with hexane is 60 mg/g or more and 85 mg/g or less.
<3> The toner according to any one of <1> and <2>, wherein the toner has pores on a surface thereof, and the average number of the pores is 0.5 to 11.0.
<4> The toner according to <3>, wherein the pores have an equivalent circle diameter of 0.2 μm or more and 3.0 μm or less.
<5> The toner according to any one of <1> to <4>, wherein an intensity ratio (P2850/P828) of a peak (P2850) derived from the release agent to a peak (P828) derived from the binder resin, which is determined by an FTIR-ATR (attenuated total reflection infrared spectroscopy) method at 120° C., is 0.20 or more.
<6> The toner according to any one of <1> to <5>, wherein a value of a ratio tan δ (G″/G′) of a storage modulus G′ to a loss viscosity modulus G″ at 120° C. of the toner is 0.80 or more and 1.50 or less.
<7> The toner according to any one of <1> to <6>, wherein an intensity ratio (P2850/P828) of a peak (P2850) derived from the release agent to a peak (P828) derived from the binder resin, measured by an FTIR-ATR method after the toner is pressed at a pressure of 40 kN, is 0.20 or more.
<8> A toner storage unit, comprising the toner according to any one of <1> to <7>.

The toner described in any one of <1> to <7> and the toner storage unit described in <8> can solve the problems of the prior art and achieve the object of the present invention.

Japanese Patent No. 6488866 JP 2017-167387 A

Claims (7)

A method for producing a toner containing at least a binder resin and a release agent, comprising the steps of:
The method includes a step of granulating toner base particles in an aqueous medium, and a step of externally adding silica to the toner base particles,
The amount of the release agent extracted with hexane is 31 mg/g or more and 95 mg/g or less,
the toner has an intensity ratio (P2850/P828) of a peak (P2850) derived from the release agent to a peak (P828) derived from the binder resin, the peak (P2850) being determined by an FTIR-ATR (attenuated total reflection infrared spectroscopy) method at 25° C., of 0.05 or less ;
The method for producing a toner , wherein the binder resin comprises a polyester resin . 2. The method for producing a toner according to claim 1, wherein an extraction amount of the release agent with the hexane is 60 mg/g or more and 85 mg/g or less. The method for producing a toner according to claim 1 , wherein the toner has pores on a surface thereof, and an average number of the pores is 0.5 to 11.0. The method for producing a toner according to claim 3, wherein the pores have an equivalent circle diameter of 0.2 μm or more and 3.0 μm or less. 5. The method for producing a toner according to claim 1, wherein the toner has an intensity ratio (P2850/P828) of a peak (P2850) derived from the release agent to a peak (P828) derived from the binder resin, the peak (P2850) being determined by an FTIR-ATR (attenuated total reflection infrared spectroscopy) method at 120° C., of 0.20 or more. 6. The method for producing a toner according to claim 1, wherein the toner has a ratio tan δ (G"/G') of a storage modulus G' to a loss viscosity modulus G" at 120° C. of 0.80 or more and 1.50 or less. 7. The method for producing a toner according to claim 1, wherein an intensity ratio (P2850/P828) of a peak (P2850) derived from the release agent to a peak (P828) derived from the binder resin, measured by an FTIR-ATR method after the toner is pressed at a pressure of 40 kN, is 0.20 or more.