WO2016167193A1 - 静電潜像現像用トナー及びその製造方法 - Google Patents
静電潜像現像用トナー及びその製造方法 Download PDFInfo
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- WO2016167193A1 WO2016167193A1 PCT/JP2016/061573 JP2016061573W WO2016167193A1 WO 2016167193 A1 WO2016167193 A1 WO 2016167193A1 JP 2016061573 W JP2016061573 W JP 2016061573W WO 2016167193 A1 WO2016167193 A1 WO 2016167193A1
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- toner
- shell layer
- resin
- particles
- latent image
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G9/00—Developers
- G03G9/08—Developers with toner particles
- G03G9/087—Binders for toner particles
- G03G9/08702—Binders for toner particles comprising macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
- G03G9/08706—Polymers of alkenyl-aromatic compounds
- G03G9/08708—Copolymers of styrene
- G03G9/08711—Copolymers of styrene with esters of acrylic or methacrylic acid
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G9/00—Developers
- G03G9/08—Developers with toner particles
- G03G9/093—Encapsulated toner particles
- G03G9/09307—Encapsulated toner particles specified by the shell material
- G03G9/09314—Macromolecular compounds
- G03G9/09321—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G9/00—Developers
- G03G9/08—Developers with toner particles
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G9/00—Developers
- G03G9/08—Developers with toner particles
- G03G9/0819—Developers with toner particles characterised by the dimensions of the particles
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G9/00—Developers
- G03G9/08—Developers with toner particles
- G03G9/0825—Developers with toner particles characterised by their structure; characterised by non-homogenuous distribution of components
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G9/00—Developers
- G03G9/08—Developers with toner particles
- G03G9/087—Binders for toner particles
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G9/00—Developers
- G03G9/08—Developers with toner particles
- G03G9/087—Binders for toner particles
- G03G9/08702—Binders for toner particles comprising macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
- G03G9/08726—Polymers of unsaturated acids or derivatives thereof
- G03G9/08728—Polymers of esters
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G9/00—Developers
- G03G9/08—Developers with toner particles
- G03G9/087—Binders for toner particles
- G03G9/08742—Binders for toner particles comprising macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
- G03G9/08755—Polyesters
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G9/00—Developers
- G03G9/08—Developers with toner particles
- G03G9/093—Encapsulated toner particles
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G9/00—Developers
- G03G9/08—Developers with toner particles
- G03G9/093—Encapsulated toner particles
- G03G9/09307—Encapsulated toner particles specified by the shell material
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G9/00—Developers
- G03G9/08—Developers with toner particles
- G03G9/093—Encapsulated toner particles
- G03G9/09307—Encapsulated toner particles specified by the shell material
- G03G9/09342—Inorganic compounds
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G9/00—Developers
- G03G9/08—Developers with toner particles
- G03G9/093—Encapsulated toner particles
- G03G9/0935—Encapsulated toner particles specified by the core material
- G03G9/09357—Macromolecular compounds
- G03G9/09371—Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G9/00—Developers
- G03G9/08—Developers with toner particles
- G03G9/093—Encapsulated toner particles
- G03G9/09392—Preparation thereof
Definitions
- the present invention relates to an electrostatic latent image developing toner and a method for producing the same.
- the toner has good fixability without heating the fixing roller as much as possible.
- a binder resin having a low melting point or glass transition point or a release agent having a low melting point is often used for preparing a toner having excellent low-temperature fixability.
- toner particles contained in the toner are likely to aggregate.
- the charge amount of the aggregated toner particles tends to be lower than that of other non-aggregated toner particles.
- Patent Document 1 describes a toner including toner particles in which hydrophilic polar groups are present on the surface of toner particles and the amount of alkali metal elements present on the surface of the toner particles is reduced.
- the present invention has been made in view of the above problems, and an object thereof is to provide an electrostatic latent image developing toner excellent in charging characteristics and a method for producing the same.
- the electrostatic latent image developing toner of the present invention has a plurality of toner particles including a toner core and a shell layer covering the surface of the toner core.
- the shell layer includes a hydrophobic thermoplastic resin and a hydrophilic water-insoluble resin having positive chargeability.
- the abundance A of the alkali metal element in the surface layer of the shell layer measured by X-ray photoelectron spectroscopy and the abundance B of the alkali metal element in the whole toner particles measured by the fluorescent X-ray method are as follows: The following formula (a) and formula (b) are satisfied.
- the method for producing a toner for developing an electrostatic latent image of the present invention is a method for producing the toner for developing an electrostatic latent image described above.
- the method for producing a toner for developing an electrostatic latent image of the present invention includes a toner core manufacturing step, a shell layer forming step, and a cleaning step.
- the toner core preparation step the toner core is prepared by a pulverization method.
- the shell layer forming step the shell layer is formed on the surface of the toner core in an aqueous medium.
- the washing step the toner particles are washed with a washing liquid so as to satisfy the formula (a) and the formula (b).
- the toner according to this embodiment is an electrostatic latent image developing toner.
- the toner according to this embodiment is a powder composed of a large number of toner particles.
- the toner according to the exemplary embodiment can be used in, for example, an electrophotographic apparatus (image forming apparatus).
- an electrostatic latent image is developed using a developer containing toner.
- charged toner is attached to the electrostatic latent image formed on the photoconductor to form a toner image.
- the toner image on the photosensitive member is transferred to an intermediate transfer member (for example, an intermediate transfer belt), and then the toner image on the intermediate transfer member is further transferred to a recording medium (for example, paper).
- the toner image is heated to fix the toner image on the recording medium.
- an image is formed on the recording medium.
- a full color image can be formed by superposing four color toner images of black, yellow, magenta, and cyan.
- the toner according to the exemplary embodiment has the following configurations (1) and (2).
- Configuration (1) The toner particles include a toner core and a shell layer that covers the surface of the toner core.
- the shell layer includes a hydrophobic thermoplastic resin and a hydrophilic water-insoluble resin having positive chargeability.
- the properties of a substance are classified into three according to the degree of affinity with water, and from the higher affinity with water, water-soluble, hydrophilic water-insoluble, and It is described as hydrophobic.
- Water-soluble indicates an affinity with water that is soluble in water. “Hydrophilic water-insoluble” refers to the affinity with water that is not soluble in water but is dispersed in water alone.
- Hydrophobic refers to the affinity with water that does not dissolve in water and does not disperse in water alone.
- Configuration (2) The abundances A and B satisfy the following formulas (a) and (b).
- the abundance A is an abundance of an alkali metal element in the surface layer of the shell layer measured by X-ray photoelectron spectroscopy.
- the abundance B is the abundance of the alkali metal element in the entire toner particles measured by the fluorescent X-ray method. Specifically, it means the abundance of the alkali metal element in the entire toner particle including the surface layer.
- the abundance B can be measured using an X-ray fluorescence spectrometer (for example, “ZSX 100e” manufactured by Rigaku Corporation).
- the range of the surface layer is determined under predetermined measurement conditions by an X-ray photoelectron spectroscopy method described later.
- the range of the surface layer is, for example, a range of 8 nm from the surface of the toner particle to the inside of the toner particle.
- Configuration (1) is useful for achieving both heat-resistant storage stability and low-temperature fixability of the toner. Specifically, it is considered that the heat-resistant storage stability of the toner is improved by coating the surface of the toner core with a shell layer.
- Configuration (2) is useful for improving the charging characteristics (for example, charge rising property and charging stability) of the toner.
- the amount of the alkali metal element present in the surface layer is small. For this reason, water tends to hardly adhere to the surface layer.
- the abundance of the alkali metal element in the toner particles does not become excessively larger than that in the surface layer, and the resistance value in the toner particles does not easily decrease. By suppressing the decrease in the resistance value inside the toner particles in this way, it is possible to suppress the deterioration of the charging characteristics of the toner. Therefore, it is considered that the toner having the configuration (2) is excellent in charging stability and charging rising property.
- the abundance A is preferably 50 ppm or more and 300 ppm or less.
- the toner according to the present embodiment has a plurality of toner particles having both configurations (1) and (2) (hereinafter referred to as toner particles according to the present embodiment).
- the toner having toner particles of this embodiment has excellent charging characteristics (see Tables 1 to 4 described later).
- the toner preferably has the toner particles of this embodiment in a proportion of 80% by mass or more, more preferably has the toner particles of this embodiment in a proportion of 90% by mass or more, and a proportion of 100% by mass. It is more preferable to have the toner particles of this embodiment.
- the toner preferably has the following configuration (2-1) in addition to the configurations (1) and (2).
- the toner preferably has the following configurations (2-2) and (2-3) in addition to the configurations (1) and (2).
- the toner preferably has the following configuration (3) in addition to the configurations (1) and (2).
- Configuration (3) The toner core is produced by a pulverization method.
- the pulverization method includes a step of mixing a plurality of types of materials (resins, etc.) to obtain a mixture, a step of melt kneading the obtained mixture to obtain a kneaded product, and a step of pulverizing the obtained kneaded product.
- a powder for example, a toner core.
- the pulverization method is a dry method.
- Configuration (3) is beneficial to satisfy equation (b) in configuration (2).
- the toner core can be produced without using any dispersant (or only with a small amount of dispersant). For this reason, when the toner core is produced by the pulverization method, the abundance of the alkali metal element in the entire toner particles can be reduced.
- a surfactant may be used to disperse the material of the shell layer.
- the surfactant may adhere to the surface of the formed shell layer. Even in such a case, the abundance of the alkali metal element in the surface layer of the shell layer can be reduced by washing the toner base particles after forming the shell layer.
- Configuration (4) The shell layer has a sea-island structure with a hydrophilic water-insoluble resin as an island and a hydrophobic thermoplastic resin as the sea.
- Configuration (5) The shell layer has a protrusion substantially composed of a hydrophilic water-insoluble resin on the surface of the shell layer. The hydrophilic water-insoluble resin has positive chargeability.
- Configuration (4) is useful for improving the charging characteristics of the toner.
- the shell layer has the above-described sea-island structure, the hydrophilicity of the surface of the shell layer is difficult to become too strong. For this reason, water hardly adheres to the surface of the shell layer. It is considered that the charging property of the toner is improved by making it difficult for water to adhere to the surface of the shell layer.
- Configuration (5) is useful for improving the charging characteristics of the toner.
- the shell layer has the protrusions on the surface, for example, when toner is used for a two-component developer, the carrier and the protrusions of the shell layer are likely to come into contact with each other. As a result, the toner is easily charged. Furthermore, since the protrusion is substantially made of a hydrophilic water-insoluble resin having positive chargeability, the toner is easily charged positively.
- the sea-island structure and protrusions on the surface of the toner particles can be observed with a scanning electron microscope (for example, “JSM-6700F” manufactured by JEOL Ltd., magnification 10,000 times).
- a scanning electron microscope for example, “JSM-6700F” manufactured by JEOL Ltd., magnification 10,000 times.
- the toner particles include a toner core and a shell layer that covers the surface of the toner core.
- the surface of the toner particles may be added with an external additive as necessary.
- the toner particles before being treated with the external additive may be referred to as toner mother particles.
- a plurality of shell layers may be laminated on the surface of the toner core.
- the toner may be used as a one-component developer. Further, a two-component developer may be prepared by mixing toner with a desired carrier.
- toner core the shell layer, and the external additive will be described.
- Acrylic and methacrylic are sometimes collectively referred to as “(meth) acrylic”.
- a compound and a derivative thereof may be generically named by adding “system” after the compound name.
- the name of a polymer is expressed by adding “system” after the compound name, it means that the repeating unit of the polymer is derived from the compound or a derivative thereof.
- the toner core includes a binder resin.
- the toner core may contain an internal additive (for example, a colorant, a release agent, a charge control agent, or a magnetic powder) in addition to the binder resin.
- an internal additive for example, a colorant, a release agent, a charge control agent, or a magnetic powder
- the binder resin, the colorant, the release agent, the charge control agent, and the magnetic powder will be described.
- Binder resin In the toner core, generally, the binder resin occupies most of the components (for example, 85% by mass or more). For this reason, it is considered that the properties of the binder resin greatly affect the properties of the entire toner core. For example, when the binder resin has an ester group, a hydroxyl group, an ether group, an acid group, or a methyl group, the toner core tends to be anionic, and the binder resin has an amino group or an amide group. In other words, the toner core tends to become cationic.
- the binder resin In order for the binder resin to have a strong anionic property, it is preferable that at least one of the hydroxyl value (OHV value) and the acid value (AV value) of the binder resin is 10 mgKOH / g or more, and each is 20 mgKOH / g or more. More preferably.
- an anionic compound for example, a compound having an ester group, a hydroxyl group, an ether group, an acid group, or a methyl group
- a cationic compound for example, a compound having an amino group or an amide group (more specifically, an amine) may be added to the toner core to impart cationicity to the toner core.
- a resin having one or more functional groups selected from the group consisting of an ester group, a hydroxyl group, an ether group, an acid group, and a methyl group is preferable, and a resin having a hydroxyl group and / or a carboxyl group is more preferable.
- a binder resin having such a functional group easily reacts with a material for forming a shell layer (hereinafter sometimes simply referred to as “shell layer material”) and is chemically bonded easily. When such a chemical bond occurs, the bond between the toner core and the shell layer becomes strong.
- a resin having a functional group containing active hydrogen in the molecule is also preferable.
- the glass transition point (Tg) of the binder resin is preferably not higher than the curing start temperature of the material of the shell layer.
- Tg glass transition point
- the Tg of the binder resin can be measured using, for example, a differential scanning calorimeter. More specifically, by measuring the endothermic curve of the sample (binder resin) using a differential scanning calorimeter, the Tg of the binder resin can be obtained from the change point of specific heat in the obtained endothermic curve.
- the softening point (Tm) of the binder resin is preferably 100 ° C. or lower, and more preferably 95 ° C. or lower.
- Tm of the binder resin is 100 ° C. or less, the toner fixability is hardly lowered even during high-speed fixing on the recording medium.
- the Tm of the binder resin is 100 ° C. or lower, when the shell layer is formed on the surface of the toner core in an aqueous medium, the toner core is likely to be partially softened during the curing reaction of the shell layer. The toner core is easily rounded by surface tension.
- Tm of binder resin can be adjusted by combining several resin which has different Tm.
- the Tm of the binder resin can be measured using, for example, a Koka type flow tester. More specifically, a sample (binder resin) is set in the Koka flow tester, and the binder resin is melted and discharged under predetermined conditions. Then, the S-curve of the binder resin is measured. The Tm of the binder resin can be read from the obtained S-shaped curve. In the obtained S-curve, if the maximum stroke value is S 1 and the low-temperature baseline stroke value is S 2 , the stroke value in the S-curve is “(S 1 + S 2 ) / 2”. The temperature (° C.) at which corresponds to the Tm of the measurement sample (binder resin).
- thermoplastic resin a thermoplastic resin is preferable.
- the thermoplastic resin that can be used as the binder resin include a styrene resin, an acrylic acid resin, an olefin resin (more specifically, a polyethylene resin or a polypropylene resin), a vinyl resin (more specifically, Specifically, a vinyl chloride resin, a polyvinyl alcohol resin, a vinyl ether resin, or an N-vinyl resin), a polyester resin, a polyamide resin, a urethane resin, a styrene-acrylic acid resin, or a styrene butadiene resin can be used.
- the styrene-acrylic acid resin and the polyester resin are excellent in the dispersibility of the colorant in the toner, the charging property of the toner, and the fixing property of the toner to the recording medium.
- the styrene-acrylic acid resin is a copolymer of a styrene monomer and an acrylic acid monomer.
- styrenic monomer examples include styrene, ⁇ -methylstyrene, p-hydroxystyrene, m-hydroxystyrene, vinyl toluene, ⁇ -chlorostyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, Or p-ethylstyrene is mentioned.
- acrylic acid monomer examples include (meth) acrylic acid, (meth) acrylic acid alkyl ester, and (meth) acrylic acid hydroxyalkyl ester.
- (meth) acrylic acid alkyl esters include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, iso-propyl (meth) acrylate, and (meth) acrylic acid n.
- hydroxyalkyl esters of (meth) acrylic acid examples include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, or (meth) acrylic acid 4 -Hydroxybutyl.
- the styrene-acrylic acid resin Hydroxyl groups can be introduced into the.
- the hydroxyl value of the resulting styrene-acrylic acid resin can be adjusted by adjusting the amount of the monomer having a hydroxyl group.
- a carboxyl group can be introduced into the styrene-acrylic acid resin by using (meth) acrylic acid (monomer).
- the acid value of the resulting styrene-acrylic acid resin can be adjusted by adjusting the amount of (meth) acrylic acid used.
- the number average molecular weight (Mn) of the styrene-acrylic acid resin is 2000 or more and 3000 or less in order to achieve both the strength of the toner core and the fixing property of the toner. Is preferred.
- the molecular weight distribution (the ratio Mw / Mn of the mass average molecular weight (Mw) to the number average molecular weight (Mn)) of the styrene-acrylic acid resin is preferably 10 or more and 20 or less. Gel permeation chromatography can be used to measure Mn and Mw of the styrene-acrylic acid resin.
- the polyester resin can be obtained by polycondensation or copolycondensation of a divalent or trivalent or higher alcohol and a divalent or trivalent or higher carboxylic acid.
- diols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,4-butenediol, 1,5- Examples include pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, or polytetramethylene glycol.
- suitable bisphenols include bisphenol A, hydrogenated bisphenol A, bisphenol A ethylene oxide adduct, or bisphenol A propylene oxide adduct.
- Suitable examples of trihydric or higher alcohols that can be used to prepare the polyester resin include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, Tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, diglycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, Examples include trimethylolpropane or 1,3,5-trihydroxymethylbenzene.
- divalent carboxylic acids that can be used to prepare the polyester resin include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, Adipic acid, sebacic acid, azelaic acid, malonic acid, succinic acid, alkyl succinic acid (more specifically, n-butyl succinic acid, isobutyl succinic acid, n-octyl succinic acid, n-dodecyl succinic acid, or isododecyl succinic acid) Acid or the like) or alkenyl succinic acid (specifically, n-butenyl succinic acid, isobutenyl succinic acid, n-octenyl succinic acid, n-dodecenyl succinic acid, or isododeceny
- Preferred examples of the trivalent or higher carboxylic acid that can be used to prepare the polyester resin include 1,2,4-benzenetricarboxylic acid (trimellitic 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, Examples include 4-cyclohexanetricarboxylic acid, tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, or empole trimer acid.
- trimellitic acid trimellitic acid
- 2,5,7-naphthalenetricarboxylic acid 1
- 2,4-naphthalenetricarboxylic acid 1,2,4-butanetricarboxylic acid
- the divalent or trivalent or higher carboxylic acid may be used as an ester-forming derivative (for example, acid halide, acid anhydride, or lower alkyl ester).
- ester-forming derivative for example, acid halide, acid anhydride, or lower alkyl ester.
- lower alkyl means an alkyl group having 1 to 6 carbon atoms.
- the acid value and hydroxyl value of the polyester resin can be adjusted by changing the amount of alcohol used and the amount of carboxylic acid used.
- the acid value and hydroxyl value of the polyester resin tend to decrease.
- the number average molecular weight (Mn) of the polyester resin is preferably 1000 or more and 2000 or less in order to achieve both the strength of the toner core and the fixing property of the toner.
- the molecular weight distribution of the polyester resin is preferably 9 or more and 21 or less.
- Gel permeation chromatography can be used for the measurement of Mn and Mw of the polyester resin.
- the toner core may contain a colorant.
- a colorant for example, a known pigment or dye can be used according to the color of the toner.
- the amount of the colorant to be used is preferably 1 part by mass or more and 20 parts by mass or less, and more preferably 3 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the binder resin.
- the toner core may contain a black colorant.
- a black colorant is carbon black.
- the black colorant may be a colorant that is toned to black using a yellow colorant, a magenta colorant, and a cyan colorant.
- the toner core may contain a color colorant such as a yellow colorant, a magenta colorant, or a cyan colorant.
- yellow colorants include condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, or arylamide compounds.
- Suitable examples of yellow colorants include C.I. I. Pigment Yellow (3, 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 97, 109, 110, 111, 120, 127, 128, 129, 147, 151, 154, 155 168, 174, 175, 176, 180, 181, 191, or 194), naphthol yellow S, Hansa yellow G, or C.I. I. Bat yellow is mentioned.
- magenta colorants examples include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, or perylene compounds.
- Suitable examples of magenta colorants include C.I. I. Pigment Red (2, 3, 5, 6, 7, 19, 23, 48: 2, 48: 3, 48: 4, 57: 1, 81: 1, 122, 144, 146, 150, 166, 169, 177 184, 185, 202, 206, 220, 221 or 254).
- cyan colorants include copper phthalocyanine compounds, anthraquinone compounds, or basic dye lake compounds. Suitable examples of cyan colorants include C.I. I. Pigment blue (1, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62, or 66), phthalocyanine blue, C.I. I. Bat Blue, or C.I. I. Acid blue.
- the toner core may contain a release agent.
- the release agent is used, for example, for the purpose of improving the fixing property or offset resistance of the toner.
- the amount of the release agent used is preferably 1 part 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 20 parts by mass or less.
- Suitable examples of the release agent include low molecular weight polyethylene, low molecular weight polypropylene, polyolefin copolymer, polyolefin wax, microcrystalline wax, paraffin wax, or aliphatic hydrocarbon wax such as Fischer-Tropsch wax; oxidized polyethylene wax or Oxides of aliphatic hydrocarbon waxes such as block copolymers of oxidized polyethylene wax; vegetable waxes such as candelilla wax, carnauba wax, wood wax, jojoba wax, or rice wax; beeswax, lanolin, or whale wax Animal waxes such as; mineral waxes such as ozokerite, ceresin, or petrolatum; waxes based on fatty acid esters such as montanic acid ester waxes or castor waxes; Nabawakkusu like, part or all of fatty acid esters are de-oxidized waxes.
- a compatibilizing agent may be added to the toner core.
- the toner core may contain a charge control agent.
- the charge control agent is used, for example, for the purpose of improving the charging stability or charge rising property of the toner.
- the toner charge rising property is an index of whether or not the toner can be charged to a predetermined charge level in a short time.
- the anionic property of the toner core can be enhanced by including a negatively chargeable charge control agent in the toner core.
- the toner core may contain magnetic powder.
- magnetic powder materials include ferromagnetic metals (more specifically, iron, cobalt, nickel, etc.) or alloys thereof, ferromagnetic metal oxides (more specifically, ferrite, magnetite, or chromium dioxide). Etc.) or a material that has been subjected to a ferromagnetization treatment (more specifically, a heat treatment or the like).
- the magnetic powder In order to suppress elution of metal ions (for example, iron ions) from the magnetic powder, it is preferable to surface-treat the magnetic powder.
- metal ions for example, iron ions
- a shell layer is formed on the surface of the toner core under acidic conditions, if a metal ion adheres to the surface of the toner core, the toner core and another toner core are easily fixed.
- By suppressing the elution of metal ions from the magnetic powder it is possible to suppress adhesion between the toner core and another toner core.
- the shell layer includes a hydrophobic thermoplastic resin and a hydrophilic water-insoluble resin having positive chargeability.
- the hydrophobic thermoplastic resin or the positively charged hydrophilic water-insoluble resin preferably includes an acrylic acid-based monomer, and includes a reactive acrylic acid ester. More preferably, it contains 2-HEMA (2-hydroxyethyl methacrylate).
- thermoplastic resin examples include acrylic acid resin, styrene-acrylic acid copolymer, silicone-acrylic acid graft copolymer, urethane resin, polyester resin, or ethylene-vinyl alcohol copolymer. Can be mentioned. Of these hydrophobic thermoplastic resins, acrylic acid resins, styrene-acrylic acid copolymers, or silicone-acrylic acid graft copolymers are preferred, and acrylic resins are preferred.
- the Tg of the hydrophobic thermoplastic resin is preferably 50 ° C. or higher and 110 ° C. or lower, and more preferably 60 ° C. or higher and 71 ° C. or lower.
- the amount of the hydrophobic thermoplastic resin is preferably 1.5 parts by mass or more and 15.0 parts by mass or less with respect to 100 parts by mass of the toner core.
- hydrophilic water-insoluble resin having positive chargeability examples include acrylic acid resin, styrene-acrylic acid copolymer, silicone-acrylic acid graft copolymer, urethane resin, polyester resin, ethylene-vinyl. Examples thereof include alcohol copolymers and resins obtained by introducing a crosslinked structure into these thermoplastic resins.
- (Meth) acrylic acid alkyl esters such as n-propyl acid or n-butyl (meth) acrylate;
- (meth) acrylic aryl esters such as phenyl (meth) acrylate; 2-hydroxy (meth) acrylic acid (Meth) acrylic hydroxyalkyl esters such as ethyl, 3-hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, or 4-hydroxybutyl (meth) acrylate;
- (meth) acrylamide Ethylene oxide adduct of (meth) acrylic acid; methyl ether, ethyl ether, n Such as propyl ether, or n- butyl ether, alkyl ethers of
- Examples of the crosslinking agent for introducing a crosslinked structure into the thermoplastic resin include a crosslinking monomer.
- the crosslinkable monomer include divinylbenzene crosslinkable monomers, diallyl phthalate crosslinkable monomers, and dimethacrylate crosslinkable monomers.
- Examples of the divinylbenzene-based crosslinkable monomer include o-divinylbenzene, m-divinylbenzene, and p-divinylbenzene.
- Examples of the diallyl phthalate-based crosslinking monomer include diallyl isophthalate and diallyl orthophthalate.
- Examples of the dimethacrylic acid ester-based crosslinking monomer include ethylene glycol dimethacrylate or triethylene glycol dimethacrylate.
- a positively chargeable charge control agent can be included.
- the mode in which the positively chargeable charge control agent is contained in the hydrophilic water-insoluble resin include, for example, a mode in which the positively chargeable charge control agent particles are dispersed in the hydrophilic water-insoluble resin, or a positively chargeable functional group. Examples thereof include a polymer having a repeating unit derived from a monomer having a group.
- the positively chargeable charge control agent dispersed in the resin include azine compounds (more specifically, pyrimidine, pyrazine, phthalazine, or quinoxaline), nigrosine compounds (more specifically, digrosine or nigrosine).
- Salts metal salts of higher fatty acids, or quaternary ammonium salts (more specifically, benzyldecylhexylmethylammonium chloride, decyltrimethylammonium chloride, etc.). These may be used alone or in combination of two or more.
- Examples of the polymer containing a repeating unit derived from a monomer having a positively charged functional group include, for example, a resin having a functional group derived from a quaternary ammonium salt, a resin having an amino group, or a resin having a carboxyl group (more specifically, Include the above-described thermoplastic trees or resins obtained by introducing a crosslinked structure into a thermoplastic resin).
- the carboxyl group may be a salt.
- a styrene-acrylic acid copolymer having an amino group or a styrene-acrylic acid copolymer having a functional group derived from a quaternary ammonium salt is preferred.
- Examples of the monomer having an amino group include a dialkylaminoalkyl ester of (meth) acrylic acid (more specifically, diethylaminoethyl (meth) acrylate), a dialkylaminoalkyl ester of alkenyl acid (more specifically, 2 -2- (dimethylamino) ethyl propenoate), dialkyl (meth) acrylamide (more specifically, dimethylacrylamide, etc.), or dialkylaminoalkyl (meth) acrylamide (more specifically, dimethylaminopropyl methacrylamide) And N-alkyl (meth) acrylamide (more specifically, N-isopropylacrylamide and the like).
- N-alkyl (meth) acrylamide is preferable.
- examples of the monomer having a functional group derived from a quaternary ammonium salt include a monomer obtained by quaternizing a monomer having the amino group as a functional group.
- a monomer obtained by quaternizing (meth) acrylic acid dialkylaminoalkyl ester more specifically, dimethylaminopropylacrylamide methyl chloride quaternary salt, etc.
- 2-((meth) acryloyloxy) alkyltrimethyl is preferable.
- the hydrophilic water-insoluble resin having positive chargeability may be a copolymer derived from a monomer having a positively chargeable functional group.
- the monomer having a positively chargeable functional group include a quaternary ammonium salt having a (meth) acryloyl group.
- quaternary ammonium salts include trimethyl-2-methacryloyloxyethylammonium chloride, (3-acrylamidopropyl) trimethylammonium chloride, or trimethylvinylammonium bromide. Of these, dimethylaminopropylacrylamide chloride quaternary salt, 2- (methacryloyloxy) trimethylammonium chloride, or N-isopropylacrylamide is preferred.
- the hydrophilic water-insoluble resin contains a polymer having a repeating unit derived from a monomer having a positively charged functional group. This is because if the hydrophilic water-insoluble resin contains such a copolymer, the charging stability of the toner is easily improved. Specifically, a repeating unit derived from a monomer having a positively chargeable functional group forms a chemical bond with a hydrophilic water-insoluble resin. For this reason, the positively chargeable charge control agent hardly bleeds out of the toner particles over time.
- the Tg of the hydrophilic water-insoluble resin having positive charging property is preferably 65 ° C. or higher and 110 ° C. or lower, and more preferably 72 ° C. or higher and 105 ° C. or lower.
- the Tg of the hydrophilic water-insoluble resin having positive chargeability is preferably larger than the Tg of the hydrophobic thermoplastic resin.
- the amount of the positively charged hydrophilic non-hydrophilic resin is preferably 0.1 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the toner core.
- An external additive may be attached to the surface of the toner particles as necessary.
- the material for the external additive include metal oxides (more specifically, alumina, titanium oxide, magnesium oxide, zinc oxide, strontium titanate, barium titanate, etc.) or silica.
- the particle diameter of the external additive is preferably 0.01 ⁇ m or more and 1.0 ⁇ m or less.
- the content of the external additive is preferably 0.5 parts by mass or more and 10 parts by mass or less, and more preferably 1 part by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the toner base particles.
- a two-component developer can be prepared by mixing the toner of this embodiment with a desired carrier.
- a magnetic carrier it is preferable to use a magnetic carrier.
- a suitable carrier is a carrier in which a carrier core is coated with a resin.
- carrier cores include iron, oxidized iron, reduced iron, magnetite, copper, silicon steel, ferrite, nickel, or cobalt particles; alloys of these materials with metals such as manganese, zinc, or aluminum Particles of iron-nickel alloy or iron-cobalt alloy; ceramics (titanium oxide, aluminum oxide, copper oxide, magnesium oxide, lead oxide, zirconium oxide, silicon carbide, magnesium titanate, barium titanate, lithium titanate , Particles of lead titanate, lead zirconate, or lithium niobate); particles of a high dielectric constant material (ammonium dihydrogen phosphate, potassium dihydrogen phosphate, or Rochelle salt).
- a resin carrier may be prepared by dispersing the particles in a resin.
- the resin covering the carrier core examples include acrylic acid polymers, styrene polymers, styrene-acrylic acid copolymers, olefin polymers (more specifically, polyethylene, chlorinated polyethylene, or polypropylene). Etc.), polyvinyl chloride, polyvinyl acetate, polycarbonate resin, cellulose resin, polyester resin, unsaturated polyester resin, polyamide resin, urethane resin, epoxy resin, silicone resin, fluororesin (more specifically, polytetrafluoroethylene) , Polychlorotrifluoroethylene, or polyvinylidene fluoride), phenol resin, xylene resin, diallyl phthalate resin, polyacetal resin, or amino resin. Two or more of these resins may be combined.
- the particle diameter of the carrier measured with an electron microscope is preferably 20 ⁇ m or more and 120 ⁇ m or less, and more preferably 25 ⁇ m or more and 80 ⁇ m or less.
- the toner content is preferably 3% by mass or more and 20% by mass or less with respect to the mass of the two-component developer. It is preferable that it is 15 mass% or less.
- the method for producing a toner for developing an electrostatic latent image according to the present embodiment includes a toner core manufacturing step, a shell layer forming step, and a cleaning step.
- a toner core is manufactured.
- a shell layer is formed on the surface of the toner core in an aqueous medium.
- Toner core manufacturing process As the toner core production process, for example, a pulverization method and an aggregation method are preferable.
- a binder resin and an internal additive for example, a colorant, a release agent, a charge control agent, or magnetic powder
- an internal additive for example, a colorant, a release agent, a charge control agent, or magnetic powder
- the obtained mixture is melted and kneaded.
- the obtained kneaded material is pulverized.
- the obtained pulverized product is classified.
- a toner core having a desired particle size can be obtained.
- the toner core can be prepared relatively easily.
- the toner core is preferably produced by a pulverization method.
- the pulverization method can reduce the amount of a dispersant (for example, a surfactant) used compared to the agglomeration method, the pulverization method can easily produce a toner core contained in the toner satisfying the formulas (a) and (b). .
- a dispersant for example, a surfactant
- the aggregation method includes, for example, an aggregation process and a coalescence process.
- a plurality of types of microparticles that are microparticulated for each component constituting the toner core are aggregated in an aqueous medium to form agglomerated particles including a plurality of types of toner core components.
- the components contained in the aggregated particles are coalesced in an aqueous medium to obtain a toner core. According to the aggregation method, it is easy to obtain a toner core having a uniform shape and a uniform particle diameter.
- the toner core obtained in the toner core preparation step and the material of the shell layer are added to an aqueous medium to prepare a toner core dispersion.
- the material for the shell layer include hydrophilic water-insoluble resin particles having positive chargeability (hereinafter referred to as positively chargeable particles) and hydrophobic thermoplastic resin particles (hereinafter referred to as hydrophobic particles). And add.
- the hydrophobic particles and the positively charged particles each adhere to the surface of the toner core. Specifically, it is considered that the positively charged particles adhere to cover the surface of the toner core to which the hydrophobic particles adhere.
- the reason for such adhesion is considered to be that the affinity of hydrophobic particles to water is lower than that of positively charged particles.
- the aqueous medium is preferably water from the viewpoint of preventing the binder resin from dissolving or the release agent from being eluted.
- the temperature of the dispersion liquid is raised to a predetermined temperature and maintained at that temperature for a predetermined time.
- the material of the shell layer attached to the surface of the toner core is cured by the polymerization reaction.
- a shell layer is formed on the surface of the toner core, and a dispersion of toner mother particles is obtained.
- the hydrophobic particles and the positively charged particles are attached to the toner core. Therefore, even if the shell layer is heated and cured, the hydrophobic particles and the positively charged particles are formed on the surface of the toner core. It is difficult to fuse. Further, since the positively charged particles before heating have hydrophilicity, it is considered that they are likely to exist at the interface between the aqueous medium and the hydrophobic particles. However, as the curing reaction of the shell layer proceeds, the hydrophilicity of the positively chargeable particles tends to weaken. For this reason, during the curing reaction of the shell layer, the positively charged particles are considered to move between the plurality of hydrophobic particles due to the capillary effect.
- the positively chargeable particles may be partially exposed from the plurality of hydrophobic particles (semi-embedded state).
- the shell layer is formed in a semi-buried state, it is considered that the protrusion is formed on the surface of the shell layer.
- a projection part is substantially comprised from the hydrophilic water-insoluble resin which has positive charging property.
- Examples of a method for satisfactorily dispersing the toner core in the aqueous medium include a method in which the toner core is mechanically dispersed in the aqueous medium using an apparatus capable of strongly stirring the dispersion.
- the pH of the aqueous medium is preferably adjusted to about 4 using an acidic substance before adding the shell layer material.
- the pH of the aqueous medium is preferably adjusted to about 4 using an acidic substance before adding the shell layer material.
- the temperature at which the shell layer is formed on the surface of the toner core is preferably 40 ° C. or more and 95 ° C. or less, more preferably 50 ° C. or more and 80 ° C. or less. preferable.
- the curing start temperature of the shell layer material is preferably higher than the Tg of the hydrophobic thermoplastic resin and lower than the Tg of the hydrophilic water-insoluble resin having positive chargeability.
- the hydrophobic thermoplastic resin can be selectively cured, and the protrusion composed of a hydrophilic water-insoluble resin having a substantially positive charging property is formed on the shell layer. Easy to form on the surface.
- the toner base particles are cleaned with a cleaning liquid.
- the dispersion liquid containing the toner base particles is cooled to room temperature (for example, 25 ° C.). Thereafter, the toner base particles are washed with a washing liquid.
- the toner base particles are cleaned using a cleaning liquid.
- the cleaning liquid include water and acid.
- the acid include inorganic acids (more specifically, boric acid, sulfuric acid, hydrochloric acid, and the like) and organic acids (more specifically, paratoluenesulfonic acid, citric acid, and the like).
- water is preferable, and water with high purity (specifically, ion-exchanged water, distilled water, etc.) is more preferable.
- a preferred cleaning method a method of recovering wet cake-like toner mother particles from a dispersion containing toner mother particles by solid-liquid separation, and washing the obtained wet cake-like toner mother particles with water.
- the toner manufacturing method includes a step of drying the toner base particles (drying step) and a step of attaching an external additive to the surface of the toner base particles (external addition) as necessary after the cleaning step.
- drying step the toner is recovered from the dispersion of toner base particles.
- the toner base particles are dried.
- Suitable methods for drying the toner base particles include a method using a dryer (for example, a spray dryer, a fluidized bed dryer, a vacuum freeze dryer, or a vacuum dryer). Among these methods, a method using a spray dryer is preferable in order to suppress aggregation of toner base particles during drying.
- the external additive can be attached to the surface of the toner base particles by spraying a dispersion of the external additive such as silica together with the dispersion of the toner base particles.
- an external additive is attached to the surface of the toner base particles.
- a suitable method for attaching the external additive using a mixer (for example, FM mixer or Nauter mixer (registered trademark)) under the condition that the external additive is not buried in the surface of the toner base particles, Examples thereof include a method of mixing toner base particles and an external additive.
- the toner manufacturing method can be arbitrarily changed according to the required configuration or characteristics of the toner.
- the toner core may be added to the solvent.
- the material of the shell layer may be dissolved in the solvent.
- the method for forming the shell layer is arbitrary.
- the shell layer may be formed by using any of an in-situ polymerization method, a submerged cured coating method, and a coacervation method. Further, each step may be omitted depending on the use of the toner.
- the toner base particles correspond to the toner particles.
- Tables 1 and 2 show the toners of Examples 1 to 13 and the toners of Comparative Examples 1 to 7 (each electrostatic latent image developing toner).
- thermoplastic resin fine particles AI A three-necked flask was used as a reaction vessel.
- This three-necked flask is a 1 L capacity reaction vessel equipped with a thermometer and stirring blades.
- the reaction vessel was set in a water bath, and 815 mL of ion exchange water and 75 mL of a cationic surfactant (“Cotamine (registered trademark) 24P” manufactured by Kao Corporation, lauryltrimethylammonium chloride) were charged into the reaction vessel. Subsequently, the internal temperature of the reaction vessel was raised to 80 ° C. using a water bath.
- thermoplastic resin fine particles AI were observed with a transmission electron microscope, and it was confirmed that the number average particle diameter was 31 nm.
- the Tg of the thermoplastic resin fine particles AI was 71 ° C. as measured by a differential scanning calorimeter.
- the thermoplastic resin fine particles AI had hydrophobicity.
- thermoplastic resin fine particles A-II A suspension of the thermoplastic fine particle A-II was prepared in the same manner as the thermoplastic fine particle AI except that the addition amount of the cationic surfactant was changed from 75 mL to 25 mL.
- the obtained thermoplastic resin fine particles A-II were observed with a transmission electron microscope, and it was confirmed that the number average particle diameter was 98 nm.
- the Tg of the thermoplastic resin fine particles A-II was 68 ° C. as measured by a differential scanning calorimeter.
- the thermoplastic resin fine particles A-II were hydrophobic.
- thermoplastic resin fine particles A-III The same method as that for the thermoplastic resin fine particles AI except that the amount of styrene used was changed from 68 mL to 80 mL and the amount of butyl acrylate was changed from 12 mL to 0 mL (no butyl acrylate was used). A suspension of thermoplastic resin fine particles A-III was prepared. The obtained thermoplastic resin fine particles A-III were observed with a transmission electron microscope, and it was confirmed that the number average particle diameter was 27 nm. The Tg of the thermoplastic resin fine particles A-III was 104 ° C. as measured by a differential scanning calorimeter. The thermoplastic resin fine particles A-III had hydrophobicity.
- a three-necked flask was used as a reaction vessel.
- This three-necked flask is a 1 L capacity reaction vessel equipped with a thermometer and stirring blades.
- the reaction vessel was set in a water bath, and 790 mL of ion-exchanged water and 30 mL of a cationic surfactant (“Coatamine (registered trademark) 24P” manufactured by Kao Corporation, lauryltrimethylammonium chloride) were charged into the reaction vessel. Subsequently, the internal temperature of the reaction vessel was raised to 80 ° C. using a water bath.
- a mixed solution of 100 mL of methyl methacrylate, 30 mL of butyl acrylate, and 20 mL of dimethylaminopropylacrylamide chloride quaternary salt was prepared.
- a potassium persulfate solution in which 0.5 g of potassium persulfate was dissolved in 30 mL of ion-exchanged water was prepared.
- the prepared mixed solution and potassium persulfate solution were added dropwise to the reaction vessel over 5 hours. Furthermore, the internal temperature of the reaction vessel was maintained at 80 ° C. for 2 hours to complete the polymerization. As a result, a suspension of positively chargeable resin fine particles BI was obtained.
- the obtained positively chargeable resin fine particles BI were observed with a transmission electron microscope, and it was confirmed that the number average particle diameter was 55 nm.
- the Tg of the positively chargeable resin fine particles BI was 103 ° C. as measured by a differential scanning calorimeter.
- the positively chargeable resin fine particles BI were hydrophilic and water-insoluble.
- a suspension of positively chargeable resin fine particles B-III was prepared in the same manner as the positively chargeable resin fine particles BI except that 20 mL of dimethylaminopropylacrylamide chloride quaternary salt was changed to 20 mL of N-isopropylacrylamide.
- the obtained positively chargeable resin fine particles B-III were observed with a transmission electron microscope, and it was confirmed that the number average particle diameter was 75 nm.
- the Tg of positively chargeable resin fine particles B-III was 72 ° C. as measured by a differential scanning calorimeter.
- the positively chargeable resin fine particles B-III were hydrophilic and water-insoluble.
- the kneaded material was coarsely pulverized with a pulverizer (“Rohtoplex (registered trademark)” manufactured by Hosokawa Micron Corporation). Subsequently, the obtained coarsely pulverized product was finely pulverized by a jet mill (“Ultrasonic Jet Mill I Type” manufactured by Nippon Pneumatic Industry Co., Ltd.). Subsequently, the obtained finely pulverized product was classified with a classifier (“Elbow Jet EJ-LABO type” manufactured by Nippon Steel Mining Co., Ltd.). As a result, a toner core was obtained.
- a three-necked flask was used as a reaction vessel.
- This three-necked flask is a 1 L capacity reaction vessel equipped with a thermometer and stirring blades.
- the reaction vessel was set in a water bath, and 300 mL of ion exchange water was charged into the reaction vessel. Subsequently, the internal temperature of the reaction vessel was maintained at 30 ° C. using a water bath. Next, sodium hydroxide was added to the reaction vessel to adjust the pH of the contents of the reaction vessel to 7. After the pH adjustment, 2 mL of the positively chargeable resin fine particle BI suspension and 30 mL of the thermoplastic resin fine particle AI suspension were added to the reaction vessel as the shell layer material.
- the shell layer material was dissolved in an aqueous medium to obtain an aqueous solution of the shell layer material.
- 300 g of the toner core was added to the obtained aqueous solution, and the contents of the reaction vessel were stirred for 1 hour at a rotation speed of 200 rpm.
- 300 mL of ion exchange water was added to the reaction vessel.
- the internal temperature of the reaction vessel was raised to 70 ° C. at a speed of + 1 ° C./min.
- the contents of the reaction vessel were continuously stirred for 2 hours under the conditions of a temperature of 70 ° C. and a rotation speed of 100 rpm.
- the contents of the reaction vessel were cooled to room temperature (25 ° C.) to obtain a dispersion containing toner mother particles.
- the wet cake-like toner base particles obtained in the washing step were dispersed in a 50% by mass aqueous ethanol solution to prepare a slurry.
- the obtained slurry was supplied to a continuous surface reformer (“Coatmizer (registered trademark)” manufactured by Freund Sangyo Co., Ltd.) to dry the toner base particles in the slurry.
- Coatmizer registered trademark
- toner mother particles were obtained. Drying conditions were set to a hot air temperature of 45 ° C. and a blower air volume of 2 m 3 / min.
- Example addition process 100 parts by mass of toner base particles obtained in the drying step and 1.0 part by mass of dry silica fine particles (“AEROSIL (registered trademark) REA90” manufactured by Nippon Aerosil Co., Ltd.) are mixed with a 10 L capacity FM mixer (Nippon Coke Industrial Co., Ltd.). The external additive was adhered to the surface of the toner base particles. Thereafter, the obtained toner was sieved with a 200 mesh (aperture 75 ⁇ m) sieve to obtain the toner of Example 1. When the toner was observed using a scanning electron microscope, it was confirmed that the shell layer of the toner had a sea-island structure and protrusions.
- AEROSIL registered trademark
- FM mixer Neippon Coke Industrial Co., Ltd.
- the confirmed sea-island structure was a structure in which a hydrophilic water-insoluble resin having positive chargeability was used as an island and a hydrophobic thermoplastic resin was used as the sea. Further, the confirmed protrusion was substantially composed of a hydrophilic water-insoluble resin having positive chargeability.
- Example 2 In the shell layer forming step, the toner of Example 2 was prepared in the same manner as the toner of Example 1 except that 30 mL of the suspension of thermoplastic resin particles A-II was used instead of 30 mL of the suspension of thermoplastic resin particles AI. Got. When observed with a scanning electron microscope in the same manner as in the observation of the shell layer in the toner of Example 1, the sea-island structure and protrusions of the shell layer were confirmed.
- Example 3 The toner of Example 3 is the same as the toner of Example 1 except that 30 mL of the suspension of the thermoplastic resin fine particles A-III is used instead of 30 mL of the suspension of the thermoplastic resin fine particles AI in the shell layer forming step. Got. When observed with a scanning electron microscope in the same manner as in the observation of the shell layer in the toner of Example 1, the sea-island structure and protrusions of the shell layer were confirmed.
- Example 4 In the shell layer forming step, Example 4 was carried out in the same manner as in Example 1 except that 2 mL of positively chargeable resin fine particle B-II suspension was used instead of 2 mL of positively chargeable resin fine particle BI suspension. Toner was obtained. When observed with a scanning electron microscope in the same manner as in the observation of the shell layer in the toner of Example 1, the sea-island structure and protrusions of the shell layer were confirmed.
- Example 5 In the shell layer forming step, Example 5 was carried out in the same manner as in the toner of Example 1, except that 2 mL of positively charged resin fine particle B-III suspension was used instead of 2 mL of positively charged resin fine particle BI suspension. Toner was obtained. When observed with a scanning electron microscope in the same manner as in the observation of the shell layer in the toner of Example 1, the sea-island structure and protrusions of the shell layer were confirmed.
- Example 6 The toner of Example 6 was prepared in the same manner as the toner of Example 1, except that the addition amount of the suspension of the thermoplastic resin fine particles AI was changed from 30 mL to 45 mL in the shell layer forming step. When observed with a scanning electron microscope in the same manner as in the observation of the shell layer in the toner of Example 1, the sea-island structure and protrusions of the shell layer were confirmed.
- Example 7 The toner of Example 7 was prepared in the same manner as the toner of Example 1, except that the addition amount of the suspension of the thermoplastic resin fine particles AI was changed from 30 mL to 15 mL in the shell layer forming step. When observed with a scanning electron microscope in the same manner as in the observation of the shell layer in the toner of Example 1, the sea-island structure and protrusions of the shell layer were confirmed.
- Example 8 A toner of Example 8 was prepared in the same manner as the toner of Example 1, except that the addition amount of the positively charged resin fine particle BI suspension was changed from 2 mL to 1 mL in the shell layer forming step. When observed with a scanning electron microscope in the same manner as in the observation of the shell layer in the toner of Example 1, the sea-island structure and protrusions of the shell layer were confirmed.
- Example 9 The toner of Example 9 was prepared in the same manner as the toner of Example 1, except that the addition amount of the positively charged resin fine particle BI suspension was changed from 2 mL to 3 mL in the shell layer forming step. When observed with a scanning electron microscope in the same manner as in the observation of the shell layer in the toner of Example 1, the sea-island structure and protrusions of the shell layer were confirmed.
- Example 10 A toner of Example 10 was prepared in the same manner as the toner of Example 1 except that 0.1N hydrochloric acid was used instead of ion-exchanged water in the first washing in the washing step. When observed with a scanning electron microscope in the same manner as in the observation of the shell layer in the toner of Example 1, the sea-island structure and protrusions of the shell layer were confirmed.
- Example 11 A toner of Example 11 was prepared in the same manner as the toner of Example 1, except that 0.1N hydrochloric acid was used instead of ion-exchanged water in the first and second washings in the washing step. When observed with a scanning electron microscope in the same manner as in the observation of the shell layer in the toner of Example 1, the sea-island structure and protrusions of the shell layer were confirmed.
- Example 12 A toner of Example 12 was prepared in the same manner as the toner of Example 1, except that sodium hydroxide was used to change the pH of the aqueous medium in the flask to 5 in the shell layer forming step. When observed with a scanning electron microscope in the same manner as in the observation of the shell layer in the toner of Example 1, the sea-island structure and protrusions of the shell layer were confirmed.
- Example 13 A toner of Example 13 was prepared in the same manner as the toner of Example 1 except that sodium hydroxide was used to change the pH of the aqueous medium in the flask to 4 in the shell layer forming step. When observed with a scanning electron microscope in the same manner as in the observation of the shell layer in the toner of Example 1, the sea-island structure and protrusions of the shell layer were confirmed.
- Comparative Example 1 In the shell layer forming step, instead of 30 mL of the suspension of the thermoplastic resin fine particles AI, the suspension of the thermoplastic resin fine particles A-IV (“Polynas (registered trademark) PS-50” manufactured by Tosoh Corporation) (water-soluble sodium polystyrene sulfonate ), Solid content 20%)
- a toner of Comparative Example 1 was prepared in the same manner as the toner of Example 1 except that 15 mL was used.
- the thermoplastic resin fine particles A-IV were water-soluble. When observed with a scanning electron microscope in the same manner as in the observation of the shell layer in the toner of Example 1, the sea-island structure and protrusions of the shell layer were not confirmed.
- Comparative Example 2 In the shell layer forming step, the suspension of positively chargeable resin fine particles B-IV (“BECKAMINE (registered trademark) A-1” manufactured by DIC Corporation) instead of 2 mL of the suspension of positively chargeable resin fine particles BI (resin: water-soluble) A toner of Comparative Example 2 was prepared in the same manner as the toner of Example 1 except that 2 mL of polyacrylamide (solid concentration: 11%) was used. The positively chargeable resin fine particles B-IV were water-soluble. When observed with a scanning electron microscope in the same manner as in the observation of the shell layer in the toner of Example 1, the sea-island structure and protrusions of the shell layer were not confirmed.
- BECKAMINE registered trademark
- A-1 manufactured by DIC Corporation
- Comparative Example 3 The toner of Comparative Example 3 was prepared in the same manner as the toner of Example 1 except that the number of washings was changed from 5 to 3 in the washing step. When observed with a scanning electron microscope in the same manner as in the observation of the shell layer in the toner of Example 1, the sea-island structure and protrusions of the shell layer were confirmed.
- Comparative Example 4 A toner of Comparative Example 4 was prepared in the same manner as the toner of Example 1 except that a 0.1N sodium hydroxide aqueous solution was used instead of ion-exchanged water in the first washing in the washing step. When observed with a scanning electron microscope in the same manner as in the observation of the shell layer in the toner of Example 1, the sea-island structure and protrusions of the shell layer were confirmed.
- Comparative Example 5 The toner of Comparative Example 5 was prepared in the same manner as the toner of Example 1, except that the pH during the reaction was changed from 7 to 8 in the shell layer forming step. When observed with a scanning electron microscope in the same manner as in the observation of the shell layer in the toner of Example 1, the sea-island structure and protrusions of the shell layer were confirmed.
- Comparative Example 6 A toner of Comparative Example 6 was prepared in the same manner as the toner of Example 1 except that the pH during the reaction was changed from 7 to 2 in the shell layer forming step. When observed with a scanning electron microscope in the same manner as in the observation of the shell layer in the toner of Example 1, the sea-island structure and protrusions of the shell layer were confirmed.
- Comparative Example 7 A toner of Comparative Example 7 was prepared in the same manner as the toner of Example 1 except that the pH during the reaction was changed from 7 to 9 in the shell layer forming step. When observed with a scanning electron microscope in the same manner as in the observation of the shell layer in the toner of Example 1, the sea-island structure and protrusions of the shell layer were confirmed.
- Heat resistant storage stability 2 g of the sample (toner) was weighed in a 20 mL capacity plastic container and allowed to stand in a thermostat set at 60 ° C. for 3 hours. As a result, a sample for heat resistant storage stability evaluation was obtained. Thereafter, a sample for heat resistant storage stability evaluation was sieved using a 100 mesh (mesh opening 150 ⁇ m) sieve under the conditions of rheostat scale 5 and time 30 seconds according to the manual of a powder tester (manufactured by Hosokawa Micron Corporation). . After sieving, the mass of the sample remaining on the sieve was measured.
- the degree of aggregation (% by mass) of the toner was calculated according to the following formula.
- Aggregation degree (mass%) (mass of sample remaining on sieve / mass of sample before sieving) ⁇ 100 From the calculated degree of aggregation, the heat resistant storage stability of the toner was evaluated according to the following criteria. ⁇ (Good): The degree of aggregation was 50% by mass or less. X (Poor): Aggregation degree exceeded 50 mass%.
- a developer carrier carrier for “TASKalfa 5550ci” manufactured by Kyocera Document Solutions Co., Ltd.
- a toner of 10% by mass with respect to the mass of the carrier are mixed for 30 minutes using a ball mill, and a two-component developer for evaluation is mixed. Prepared.
- An image was formed using the two-component developer prepared as described above, and the low-temperature fixability of the toner was evaluated.
- a color printer having a Roller-Roller type heat and pressure type fixing device (nip width 8 mm) was used as an evaluation machine.
- This color printer was an evaluation machine in which “FS-C5250DN” manufactured by Kyocera Document Solutions Co., Ltd. was modified to change the fixing temperature.
- the two-component developer prepared as described above was put into a developing device of an evaluation machine, and a sample (toner) was put into a toner container of the evaluation machine.
- the evaluation paper When evaluating the fixability of the sample (toner), the evaluation paper is used on the evaluation paper under the conditions of a linear speed of 200 mm / second (nip passage time of 40 milliseconds) and a toner applied amount of 1.0 mg / cm 2. An evaluation image was formed.
- the evaluation paper was A4 size and 90 g / m 2 paper.
- the evaluation image was a solid image having a size of 25 mm ⁇ 25 mm and a printing rate of 100%.
- the paper on which the image for evaluation was formed was passed through the fixing device.
- the setting range of the fixing temperature was 100 ° C. or higher and 200 ° C. or lower. Specifically, the fixing temperature of the fixing device was gradually increased from 100 ° C., and the minimum temperature (minimum fixing temperature) at which the toner (solid image) can be fixed on the evaluation paper was measured.
- the toner could be fixed in the measurement of the minimum fixing temperature was confirmed by a rubbing test as shown below. Specifically, the evaluation paper was folded in half so that the surface on which the image for evaluation was formed was on the inside, and a 1 kg weight covered with a cloth was used to rub the crease 5 times. Subsequently, the evaluation paper was expanded and the bent portion (the portion where the solid image was formed) of the evaluation paper was observed. Then, the length (peeling length) of toner peeling at the bent portion was measured. The lowest temperature among the fixing temperatures at which the peeling length was less than 1 mm was defined as the lowest fixing temperature.
- the low temperature fixing property was evaluated according to the following criteria. ⁇ (Good): The minimum fixing temperature was 160 ° C. or lower. X (Poor): The minimum fixing temperature was over 160 ° C.
- a Cu—Zn ferrite carrier (“F-80” manufactured by Powdertech) was added to the toner base particles of the sample (toner) to prepare a developer having a toner concentration of 10% by mass.
- the prepared developer was allowed to stand overnight under a room temperature environment (R / R environment: temperature 20 ° C., relative humidity 65% RH).
- the developer that was allowed to stand was mixed for 3 minutes using a mixing device (“Turbler (registered trademark) mixer” manufactured by WAB).
- a Q / m meter (“MODEL 210HS-2A” manufactured by Trek)
- the charge amount after mixing for 3 minutes was measured.
- charge amount of the toner in the developer after mixing for 30 minutes (hereinafter, referred to as “charge amount” after mixing for 3 minutes) is the same as the charge amount after mixing for 3 minutes, except that the mixing time of the developer that has been allowed to stand is changed from 3 minutes to 30 minutes. The charge amount after mixing for 30 minutes is measured).
- Charge rising ratio (%) (charge amount after mixing for 3 minutes / charge amount after mixing for 30 minutes) ⁇ 100 From the calculated charge rising ratio, the toner charge rising performance was evaluated according to the following criteria. ⁇ (Good): Charge rising ratio was 60% or more. X (Poor): Charge rising ratio was less than 60%.
- the mixed developer was mixed in the same manner as the charge amount in the R / R environment, except that the prepared developer was allowed to stand in a high temperature and high humidity environment (H / H environment: temperature 32 ° C., humidity 80% RH).
- the charge amount of the toner in the developer (hereinafter referred to as the charge amount in the H / H environment) was measured. From the obtained charge amount in the H / H environment and the charge amount in the R / R environment, the environmental charge amount change rate was calculated according to the following formula.
- Environmental charge amount change rate (%) [(charge amount in H / H environment) ⁇ (charge amount in R / R environment)] ⁇ 100
- the charging stability of the toner was evaluated according to the following criteria. ⁇ (Good): The rate of change in environmental charge was 80% or more. X (Poor): Environmental charge amount change rate was less than 80%.
- a sample (toner) of 0.5 g was put in a tablet molding machine having an inner diameter of 10 mm and molded while being heated to 80 ° C. As a result, a thin film sample for measurement was obtained. Immediately before the measurement, the measurement sample was pretreated (Ar etching) to remove contaminants on the surface of the measurement sample. Ar etching was performed under the conditions of Ar gas 0.5 MPa and acceleration voltage 1 kV.
- the measured value according to the abundance A was obtained using the X-ray photoelectron spectrometer ("Model 5400" by ULVAC-PHI).
- the measurement conditions are as follows.
- Measurement area (X-ray irradiation range): Diameter 1mm ⁇ N number: 3 or more ⁇ PassEnergy: 70 eV -StepSize: 0.25 eV ⁇ Measurement elements: Alkali metal elements (sodium, potassium)
- the abundance A of the alkali metal element in the surface layer of the shell layer (the alkali metal element in the surface layer of the shell layer measured by X-ray photoelectron spectroscopy). The abundance A) was determined.
- the measured value according to the abundance B was obtained using the fluorescent-X-ray-analysis apparatus ("ZSX 100e" by Rigaku Corporation).
- the measurement conditions are as follows.
- ⁇ X-ray source Rh -Voltage / current value of X-ray source: 50 kV, 50 mA
- Calibration curve A calibration curve was prepared by measuring the net intensity of fluorescent X-rays for all the constituent elements of the toner particles.
- Measurement elements Alkali metal elements (sodium, potassium)
- the abundance of the alkali metal element in the whole toner particles (the abundance B of the alkali metal element in the whole toner particles measured by the fluorescent X-ray method) is obtained. It was.
- evaluation results The evaluation results for each of the samples (the toners of Examples 1 to 13 and Comparative Examples 1 to 7) are as follows.
- Tables 3 and 4 show the evaluation results of the low-temperature fixability, heat-resistant storage stability, and charge stability (specifically, charge stability and charge riseability) of the toner.
- the toner according to Examples 1 to 13 was a toner having the above-described configuration (1). Specifically, each of the toners according to Examples 1 to 13 includes toner particles including a toner core and a shell layer that covers the surface of the toner core.
- the shell layer contained a hydrophobic thermoplastic resin and a hydrophilic water-insoluble resin having positive chargeability.
- the toner according to Examples 1 to 13 was a toner having the above-described configuration (2). Specifically, the toners according to Examples 1 to 13 each had an abundance A of 300 ppm or less and a ratio value A / B of 0.5 or more and less than 1.0.
- the toners according to Examples 1 to 13 were superior to the toners according to Comparative Examples 1 to 7 in terms of low-temperature fixability, heat-resistant storage stability, and charging characteristics (charging stability and charge rising property), respectively.
- the toners according to Examples 1, 3 to 6, and 8 to 9 were toners having the above-described configuration (2-1). Specifically, the toners according to Examples 1, 3 to 6, and 8 to 9 each had an abundance A of more than 230 ppm and 300 ppm or less.
- the toners of Examples 1, 3 to 6, and 8 to 9 had an aggregation rate of 28% or less in the heat resistant storage stability evaluation.
- the toners according to Examples 1, 3 to 6, and 8 to 9 were more excellent in heat resistant storage stability than the toners according to Examples 2, 7, and 10 to 13.
- the toner according to Examples 10 to 13 was a toner having the above-described configuration (2-2). Specifically, the toners according to Examples 10 to 13 each had an abundance A greater than 180 ppm and less than 230 ppm.
- the toners of Examples 10 to 13 had a charge amount change rate of 88% or more in the evaluation of charge stability.
- the toners according to Examples 10 to 13 were more excellent in charging stability than the toners according to Examples 1 to 9.
- the toner according to Examples 12 to 13 was a toner having the above-described configurations (2-2) and (2-3). Specifically, the toners according to Examples 12 to 13 each had an abundance A of more than 180 ppm and less than 230 ppm, and A / B of 0.8 to 0.9.
- the toners according to Examples 12 to 13 had a charge rise ratio of 84% or more in the evaluation of charge rise.
- the toners according to Examples 12 to 13 were more excellent in charge rising property than the toners according to Examples 1 to 11.
- the electrostatic latent image developing toner according to the present invention can be used for forming an image in, for example, a copying machine or a printer.
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Abstract
Description
A≦300ppm・・・(a)
0.5≦A/B<1.0・・・(b)
構成(1):トナー粒子は、トナーコアと、トナーコアの表面を被覆するシェル層とを含む。シェル層は、疎水性熱可塑性樹脂と、正帯電性を有する親水性非水溶性樹脂とを含む。なお、本明細書においては、物質の性質を、水との親和性の度合いに応じて3つに区分して、水との親和性が高い方から、水溶性、親水性非水溶性、及び疎水性と記載する。水溶性とは、水に溶解する程度である、水との親和性を示す。親水性非水溶性とは、水に溶解しないが単独で水中に分散する程度である、水との親和性を示す。疎水性とは、水に溶解せず単独で水中に分散しない程度である、水との親和性を示す。
構成(2):存在量A及びBは、以下に示す式(a)及び式(b)を満たす。なお、存在量Aは、X線光電子分光法で測定されるシェル層の表面層におけるアルカリ金属元素の存在量である。存在量Bは、蛍光X線法で測定されるトナー粒子全体におけるアルカリ金属元素の存在量である。詳しくは表面層を含めたトナー粒子全体におけるアルカリ金属元素の存在量を意味する。存在量Bは蛍光X線分光分析装置(例えば、株式会社リガク製「ZSX 100e」)を用いて測定することができる。
A≦300ppm・・・(a)
0.5≦A/B<1.0・・・(b)
構成(2-1):存在量Aは、以下に示す式(c)を満たす。
230ppm<A≦300ppm・・・(c)
構成(2-2):存在量Aは、以下に示す式(d)を満たす。
180ppm<A<230ppm・・・(d)
構成(2-3):存在量Aと存在量Bとは、以下に示す式(e)を満たす。
0.8≦A/B≦0.9・・・(e)
構成(3):トナーコアは、粉砕法で作製される。なお、粉砕法は、複数種類の材料(樹脂等)を混合して混合物を得る工程と、得られた混合物を溶融混練して混練物を得る工程と、得られた混練物を粉砕する工程とを経て、粉体(例えば、トナーコア)を得る方法である。粉砕法は、乾式法である。
構成(4):シェル層は、親水性非水溶性樹脂を島とし、疎水性熱可塑性樹脂を海とする海島構造を有する。
構成(5):シェル層は、シェル層の表面に実質的に親水性非水溶性樹脂から構成される突起部を有する。親水性非水溶性樹脂は、正帯電性を有する。
トナーコアは結着樹脂を含む。トナーコアは、結着樹脂に加え、内添剤(例えば、着色剤、離型剤、電荷制御剤、又は磁性粉)を含んでもよい。以下、結着樹脂、着色剤、離型剤、電荷制御剤、及び磁性粉を説明する。
トナーコアにおいては、一般的に、成分の大部分(例えば、85質量%以上)を結着樹脂が占める。このため、結着樹脂の性質がトナーコア全体の性質に大きな影響を与えると考えられる。例えば、結着樹脂がエステル基、水酸基、エーテル基、酸基、又はメチル基を有する場合には、トナーコアはアニオン性になる傾向が強くなり、結着樹脂がアミノ基、又はアミド基を有する場合には、トナーコアはカチオン性になる傾向が強くなる。結着樹脂が強いアニオン性を有するためには、結着樹脂の水酸基価(OHV値)及び酸価(AV値)の少なくとも一方が10mgKOH/g以上であることが好ましく、各々20mgKOH/g以上であることがより好ましい。また、アニオン性の化合物(例えば、エステル基、水酸基、エーテル基、酸基、又はメチル基を有する化合物)をトナーコアに加えることで、トナーコアにアニオン性を付与してもよい。また、カチオン性の化合物(例えば、アミノ基、又はアミド基を有する化合物(より具体的には、アミン等))をトナーコアに加えることで、トナーコアにカチオン性を付与してもよい。
トナーコアは、着色剤を含んでいてもよい。着色剤としては、例えば、トナーの色に合わせて公知の顔料又は染料を用いることができる。着色剤の使用量は、結着樹脂100質量部に対して、1質量部以上20質量部以下であることが好ましく、3質量部以上10質量部以下であることがより好ましい。
トナーコアは、離型剤を含有していてもよい。離型剤は、例えばトナーの定着性又は耐オフセット性を向上させる目的で使用される。トナーコアのアニオン性を強めるためには、アニオン性を有するワックスを用いてトナーコアを作製することが好ましい。トナーの定着性又は耐オフセット性を向上させるためには、離型剤の使用量は、結着樹脂100質量部に対して、1質量部以上30質量部以下であることが好ましく、3質量部以上20質量部以下であることがより好ましい。
トナーコアは、電荷制御剤を含んでいてもよい。電荷制御剤は、例えば、トナーの帯電安定性又は帯電立ち上がり性を向上させる目的で使用される。トナーの帯電立ち上がり性は、短時間で所定の帯電レベルにトナーを帯電可能か否かの指標になる。また、トナーコアに負帯電性の電荷制御剤を含ませることで、トナーコアのアニオン性を強めることができる。
トナーコアは、磁性粉を含んでいてもよい。磁性粉の材料としては、例えば、強磁性金属(より具体的には、鉄、コバルト、又はニッケル等)若しくはその合金、強磁性金属酸化物(より具体的には、フェライト、マグネタイト、又は二酸化クロム等)、又は強磁性化処理(より具体的には、熱処理等)が施された材料が挙げられる。
既に述べたように、シェル層は、疎水性熱可塑性樹脂と、正帯電性を有する親水性非水溶性樹脂とを含む。シェル層の膜質を向上させるためには、疎水性熱可塑性樹脂、又は正帯電性を有する親水性非水溶性樹脂は、アクリル酸系モノマーを含むことが好ましく、反応性アクリル酸エステルを含むことがより好ましく、2-HEMA(メタクリル酸2-ヒドロキシエチル)を含むことが特に好ましい。
疎水性熱可塑性樹脂の具体例としては、アクリル酸系樹脂、スチレン-アクリル酸系共重合体、シリコーン-アクリル酸系グラフト共重合体、ウレタン樹脂、ポリエステル樹脂、又はエチレン-ビニルアルコール共重合体が挙げられる。これらの疎水性熱可塑性樹脂のうち、アクリル酸系樹脂、スチレン-アクリル酸系共重合体、又はシリコーン-アクリル酸系グラフト共重合体が好ましく、アクリル酸系樹脂が好ましい。
正帯電性を有する親水性非水溶性樹脂に具体例としては、アクリル酸系樹脂、スチレン-アクリル酸系共重合体、シリコーン-アクリル酸系グラフト共重合体、ウレタン樹脂、ポリエステル樹脂、エチレン-ビニルアルコール共重合体、又はこれらの熱可塑性樹脂に架橋構造を導入した樹脂が挙げられる。
トナー粒子の表面には、必要に応じて外添剤を付着させてもよい。外添剤の材料としては、例えば、金属酸化物(より具体的には、アルミナ、酸化チタン、酸化マグネシウム、酸化亜鉛、チタン酸ストロンチウム、又はチタン酸バリウム等)、又はシリカが挙げられる。
以下、本実施形態に係る静電潜像現像用トナーの製造方法について説明する。本実施形態に係る静電潜像現像用トナーの製造方法は、トナーコア作製工程と、シェル層形成工程と、洗浄工程とを含む。トナーコア作製工程では、トナーコアを作製する。シェル層形成工程では、水性媒体中でトナーコアの表面にシェル層を形成する。
トナーコア作製工程としては、例えば、粉砕法、凝集法が好ましい。
シェル形成工程では、まず、水性媒体に、トナーコア作製工程で得られたトナーコアと、シェル層の材料とを添加し、トナーコア分散液を調製する。シェル層の材料としては、例えば、正帯電性を有する親水性非水溶性樹脂粒子(以下、正帯電性粒子と記載する)と、疎水性熱可塑性樹脂粒子(以下、疎水性粒子と記載する)とを添加する。水性媒体中では、疎水性粒子及び正帯電性粒子が各々、トナーコアの表面に付着する。詳しくは、疎水性粒子が付着したトナーコアの表面を覆うように正帯電性粒子が付着すると考えられる。このように付着する理由は、疎水性粒子の水への親和性が、正帯電性粒子に比べて低いためであると考えられる。水性媒体としては、結着樹脂の溶解又は離型剤の溶出を防ぐ観点から、水が好ましい。
洗浄工程では、トナー母粒子を洗浄液で洗浄する。上記のようにしてシェル層を形成した後、トナー母粒子を含む分散液を常温(例えば、25℃)まで冷却する。その後、トナー母粒子を洗浄液で洗浄する。
3つ口フラスコを反応容器として用いた。この3つ口フラスコは、温度計及び攪拌羽根を備えた容量1Lの反応容器である。反応容器をウォーターバスにセットし、反応容器に、イオン交換水815mL及びカチオン界面活性剤(花王株式会社製「コータミン(登録商標)24P」、ラウリルトリメチルアンモニウムクロライド)75mLを投入した。続けて、ウォーターバスを用いて反応容器の内温を80℃に昇温した。その後、スチレン68mL及びアクリル酸ブチル12mLの混合液を調製した。そして、過硫酸カリウム0.5gをイオン交換水30mLに溶かした過硫酸カリウム溶液を調製した。調製した混合液及び過硫酸カリウム溶液を各々5時間かけて反応容器に滴下した。更に、反応容器の内温を80℃で2時間保持して重合を完結させた。その結果、熱可塑性樹脂微粒子A-Iのサスペンションを得た。得られた熱可塑性樹脂微粒子A-Iを透過型電子顕微鏡で観察し、数平均粒子径が31nmであることを確認した。また、熱可塑性樹脂微粒子A-IのTgは示差走査型熱量計による測定で71℃であった。なお、熱可塑性樹脂微粒子A-Iは疎水性を有していた。
カチオン界面活性剤の添加量を75mLから25mLに変更した以外は、熱可塑性樹脂微粒子A-Iと同様の方法で熱可塑性樹脂微粒子A-IIのサスペンションを作製した。得られた熱可塑性樹脂微粒子A-IIを透過型電子顕微鏡で観察し、数平均粒子径が98nmであることを確認した。また熱可塑性樹脂微粒子A-IIのTgは示差走査型熱量計による測定で68℃であった。なお、熱可塑性樹脂微粒子A-IIは疎水性を有していた。
スチレンの使用量を68mLから80mLに変更し、及びアクリル酸ブチルの使用量を12mLから0mLに変更した(アクリル酸ブチルを使用しなかった)以外は、熱可塑性樹脂微粒子A-Iと同様の方法で熱可塑性樹脂微粒子A-IIIのサスペンションを作製した。得られた熱可塑性樹脂微粒子A-IIIを透過型電子顕微鏡で観察し、数平均粒子径が27nmであることを確認した。また、熱可塑性樹脂微粒子A-IIIのTgは示差走査型熱量計による測定で104℃であった。なお、熱可塑性樹脂微粒子A-IIIは疎水性を有していた。
3つ口フラスコを反応容器として用いた。この3つ口フラスコは、温度計及び攪拌羽根を備えた容量1Lの反応容器である。反応容器をウォーターバスにセットし、反応容器に、イオン交換水790mL及びカチオン界面活性剤(花王株式会社製「コータミン(登録商標)24P」、ラウリルトリメチルアンモニウムクロライド)30mLを投入した。続けて、ウォーターバスを用いて反応容器の内温を80℃に昇温した。その後、メタクリル酸メチル100mL、アクリル酸ブチル30mL、及びジメチルアミノプロピルアクリルアミド塩化四級塩20mLの混合液を調製した。そして、過硫酸カリウム0.5gをイオン交換水30mLに溶かした過硫酸カリウム溶液を調製した。調製した混合液及び過硫酸カリウム溶液を各々5時間かけて反応容器に滴下した。更に、反応容器の内温を80℃で2時間保持して重合を完結させた。その結果、正帯電性樹脂微粒子B-Iのサスペンションを得た。得られた正帯電性樹脂微粒子B-Iを透過型電子顕微鏡で観察し、数平均粒子径が55nmであることを確認した。また、正帯電性樹脂微粒子B-IのTgは示差走査型熱量計による測定で103℃であった。なお、正帯電性樹脂微粒子B-Iは親水性非水溶性を有していた。
ジメチルアミノプロピルアクリルアミド塩化四級塩20mLを2-(メタクリロイルオキシ)エチルトリメチルアンモニウムクロリド20mLに変更した以外は、正帯電性樹脂微粒子B-Iと同様の方法で正帯電性樹脂微粒子B-IIのサスペンションを作製した。得られた正帯電性樹脂微粒子B-IIを透過型電子顕微鏡で観察し、数平均粒子径が42nmであることを確認した。また、正帯電性樹脂微粒子B-IIのTgは示差走査型熱量計による測定で110℃であった。なお、正帯電性樹脂微粒子B-IIは親水性非水溶性を有していた。
ジメチルアミノプロピルアクリルアミド塩化四級塩20mLをN-イソプロピルアクリルアミド20mLに変更した以外は、正帯電性樹脂微粒子B-Iと同様の方法で正帯電性樹脂微粒子B-IIIのサスペンションを作製した。得られた正帯電性樹脂微粒子B-IIIを透過型電子顕微鏡で観察し、数平均粒子径が75nmであることを確認した。また、正帯電性樹脂微粒子B-IIIのTgは示差走査型熱量計による測定で72℃であった。なお、正帯電性樹脂微粒子B-IIIは親水性非水溶性を有していた。
(トナーコアの作製)
低粘度ポリエステル樹脂(Tg=38℃、Tm=65℃)750gと、中粘度ポリエステル樹脂(Tg=53℃、Tm=84℃)100gと、高粘度ポリエステル樹脂(Tg=71℃、Tm=120℃)150gと、離型剤(カルナバワックス、株式会社加藤洋行製「カルナウバワックス1号」)55gと、着色剤(フタロシアニンブルー、DIC株式会社製「KET BLUE 111」)40gとをFMミキサー(日本コークス工業株式会社製)を用いて回転速度2400rpmで混合した。得られた混合物を、二軸押出機(株式会社池貝製「PCM-30」)を用いて、材料投入量5kg/時、回転速度160rpm、設定温度範囲100℃以上130℃以下の条件で溶融し、混練した。得られた混練物を冷却した後、混練物を粉砕機(ホソカワミクロン株式会社製「ロートプレックス(登録商標)」)で粗粉砕した。次いで、得られた粗粉砕品をジェットミル(日本ニューマチック工業株式会社製「超音波ジェットミルI型」)で微粉砕した。続けて、得られた微粉砕品を分級機(日鉄鉱業株式会社製「エルボージェットEJ-LABO型」)で分級した。その結果、トナーコアが得られた。
3つ口フラスコを反応容器として用いた。この3つ口フラスコは、温度計及び攪拌羽根を備えた容量1Lの反応容器である。反応容器をウォーターバスにセットし、反応容器にイオン交換水300mLを投入した。続けて、ウォーターバスを用いて反応容器の内温を30℃に保持した。次いで、反応容器に水酸化ナトリウムを加えて、反応容器の内容物のpHを7に調整した。pH調整後、反応容器に、シェル層の原料として、正帯電性樹脂微粒子B-Iのサスペンション2mLと、熱可塑性樹脂微粒子A-Iのサスペンション30mLとを添加した。シェル層の材料を水性媒体に溶解させ、シェル層の材料の水溶液を得た。得られた水溶液に300gのトナーコアを添加し、反応容器の内容物を回転速度200rpmで1時間攪拌した。次いで、反応容器に、イオン交換水300mLを追加した。その後、フラスコの内容物を回転速度100rpmで攪拌しながら、+1℃/分の速度で反応容器の内温を70℃まで昇温した。その後、温度70℃及び回転速度100rpmの条件で反応容器の内容物を2時間攪拌し続けた。次いで、反応容器の内容物を、常温(25℃)まで冷却して、トナー母粒子を含む分散液を得た。
ブフナーロートを用いて、トナー母粒子を含む分散液から、ウェットケーキ状のトナー母粒子を濾取した。続けて、ウェットケーキ状のトナー母粒子を再度イオン交換水に分散させてトナー母粒子を洗浄した。こうしたイオン交換水によるトナー母粒子の洗浄を5回繰り返した。
洗浄工程で得られたウェットケーキ状のトナー母粒子を、50質量%のエタノール水溶液に分散させてスラリーを調製した。得られたスラリーを連続式表面改質装置(フロイント産業株式会社製「コートマイザー(登録商標)」)に供給することにより、スラリー中のトナー母粒子を乾燥させた。その結果、トナー母粒子を得た。乾燥条件は、熱風温度45℃、及びブロアー風量2m3/分に設定した。
乾燥工程で得られたトナー母粒子100質量部と、乾式シリカ微粒子(日本アエロジル株式会社製「AEROSIL(登録商標)REA90」)1.0質量部とを、容量10LのFMミキサー(日本コークス工業株式会社製)を用いて5分間混合して、トナー母粒子の表面に外添剤を付着させた。その後、得られたトナーを、200メッシュ(目開き75μm)の篩により篩別して、実施例1のトナーを得た。走査型電子顕微鏡を用いてトナーを観察したところ、トナーのシェル層は、海島構造及び突起物を有することが確認された。確認された海島構造は、正帯電性を有する親水性非水溶性樹脂を島とし、疎水性熱可塑性樹脂を海とする構造であった。また、確認された突起物は、正帯電性を有する親水性非水溶性樹脂から実質的に構成されていた。
シェル層形成工程において、熱可塑性樹脂微粒子A-Iのサスペンション30mLの代わりに熱可塑性樹脂微粒子A-IIのサスペンション30mLを使用した以外は、実施例1のトナーと同様の方法で実施例2のトナーを得た。実施例1のトナーにおけるシェル層の観察と同様にして、走査型電子顕微鏡で観察したところ、シェル層の海島構造及び突起部が確認された。
シェル層形成工程において、熱可塑性樹脂微粒子A-Iのサスペンション30mLの代わりに熱可塑性樹脂微粒子A-IIIのサスペンション30mLを使用した以外は、実施例1のトナーと同様の方法で実施例3のトナーを得た。実施例1のトナーにおけるシェル層の観察と同様にして、走査型電子顕微鏡で観察したところ、シェル層の海島構造及び突起部が確認された。
シェル層形成工程において、正帯電性樹脂微粒子B-Iのサスペンション2mLの代わりに正帯電性樹脂微粒子B-IIのサスペンション2mLを使用した以外は、実施例1のトナーと同様の方法で実施例4のトナーを得た。実施例1のトナーにおけるシェル層の観察と同様にして、走査型電子顕微鏡で観察したところ、シェル層の海島構造及び突起部が確認された。
シェル層形成工程において、正帯電性樹脂微粒子B-Iのサスペンション2mLの代わりに正帯電性樹脂微粒子B-IIIのサスペンション2mLを使用した以外は、実施例1のトナーと同様の方法で実施例5のトナーを得た。実施例1のトナーにおけるシェル層の観察と同様にして、走査型電子顕微鏡で観察したところ、シェル層の海島構造及び突起部が確認された。
シェル層形成工程において、熱可塑性樹脂微粒子A-Iのサスペンションの添加量を30mLから45mLに変更した以外は実施例1のトナーと同様の方法で実施例6のトナーを調製した。実施例1のトナーにおけるシェル層の観察と同様にして、走査型電子顕微鏡で観察したところ、シェル層の海島構造及び突起部が確認された。
シェル層形成工程において、熱可塑性樹脂微粒子A-Iのサスペンションの添加量を30mLから15mLに変更した以外は実施例1のトナーと同様の方法で実施例7のトナーを調製した。実施例1のトナーにおけるシェル層の観察と同様にして、走査型電子顕微鏡で観察したところ、シェル層の海島構造及び突起部が確認された。
シェル層形成工程において、正帯電性樹脂微粒子B-Iのサスペンションの添加量を2mLから1mLに変更した以外は実施例1のトナーと同様の方法で実施例8のトナーを調製した。実施例1のトナーにおけるシェル層の観察と同様にして、走査型電子顕微鏡で観察したところ、シェル層の海島構造及び突起部が確認された。
シェル層形成工程において、正帯電性樹脂微粒子B-Iのサスペンションの添加量を2mLから3mLに変更した以外は実施例1のトナーと同様の方法で実施例9のトナーを調製した。実施例1のトナーにおけるシェル層の観察と同様にして、走査型電子顕微鏡で観察したところ、シェル層の海島構造及び突起部が確認された。
洗浄工程における初回の洗浄でイオン交換水に代えて0.1N塩酸を用いた以外は、実施例1のトナーと同様の方法で実施例10のトナーを調製した。実施例1のトナーにおけるシェル層の観察と同様にして、走査型電子顕微鏡で観察したところ、シェル層の海島構造及び突起部が確認された。
洗浄工程における初回及び2回目の洗浄でイオン交換水に代えて0.1N塩酸を用いた以外は、実施例1のトナーと同様の方法で実施例11のトナーを調製した。実施例1のトナーにおけるシェル層の観察と同様にして、走査型電子顕微鏡で観察したところ、シェル層の海島構造及び突起部が確認された。
シェル層形成工程において、水酸化ナトリウムを用いて、フラスコ内の水性媒体のpHを5に変更した以外は、実施例1のトナーと同様の方法で実施例12のトナーを調製した。実施例1のトナーにおけるシェル層の観察と同様にして、走査型電子顕微鏡で観察したところ、シェル層の海島構造及び突起部が確認された。
シェル層形成工程において、水酸化ナトリウムを用いて、フラスコ内の水性媒体のpHを4に変更した以外は、実施例1のトナーと同様の方法で実施例13のトナーを調製した。実施例1のトナーにおけるシェル層の観察と同様にして、走査型電子顕微鏡で観察したところ、シェル層の海島構造及び突起部が確認された。
シェル層形成工程において、熱可塑性樹脂微粒子A-Iのサスペンション30mLの代わりに熱可塑性樹脂微粒子A-IVのサスペンション(東ソー株式会社製「ポリナス(登録商標) PS-50」(水溶性ポリスチレンスルホン酸ナトリウム)、固形分濃度20%)15mLを使用した以外は実施例1のトナーと同様の方法で比較例1のトナーを調製した。なお、熱可塑性樹脂微粒子A-IVは水溶性であった。実施例1のトナーにおけるシェル層の観察と同様にして、走査型電子顕微鏡で観察したところ、シェル層の海島構造及び突起部が確認されなかった。
シェル層形成工程において、正帯電性樹脂微粒子B-Iのサスペンション2mLの代わりに正帯電性樹脂微粒子B-IVのサスペンション(DIC株式会社製「BECKAMINE(登録商標) A-1」.樹脂:水溶性ポリアクリルアミド、固形分濃度:11%)2mLを使用した以外は実施例1のトナーと同様の方法で比較例2のトナーを調製した。なお、正帯電性樹脂微粒子B-IVは水溶性を有していた。実施例1のトナーにおけるシェル層の観察と同様にして、走査型電子顕微鏡で観察したところ、シェル層の海島構造及び突起部が確認されなかった。
洗浄工程において、洗浄回数を5回から3回に変更した以外は実施例1のトナーと同様の方法で比較例3のトナーを調製した。実施例1のトナーにおけるシェル層の観察と同様にして、走査型電子顕微鏡で観察したところ、シェル層の海島構造及び突起部が確認された。
洗浄工程における初回の洗浄で、イオン交換水に代えて、0.1N水酸化ナトリウム水溶液を用いた以外は実施例1のトナーと同様の方法で比較例4のトナーを調製した。実施例1のトナーにおけるシェル層の観察と同様にして、走査型電子顕微鏡で観察したところ、シェル層の海島構造及び突起部が確認された。
シェル層形成工程において、反応時のpHを7から8に変更した以外は、実施例1のトナーと同様の方法で比較例5のトナーを調製した。実施例1のトナーにおけるシェル層の観察と同様にして、走査型電子顕微鏡で観察したところ、シェル層の海島構造及び突起部が確認された。
シェル層形成工程において、反応時のpHを7から2に変更した以外は、実施例1のトナーと同様の方法で比較例6のトナーを調製した。実施例1のトナーにおけるシェル層の観察と同様にして、走査型電子顕微鏡で観察したところ、シェル層の海島構造及び突起部が確認された。
シェル層形成工程において、反応時のpHを7から9に変更した以外は、実施例1のトナーと同様の方法で比較例7のトナーを調製した。実施例1のトナーにおけるシェル層の観察と同様にして、走査型電子顕微鏡で観察したところ、シェル層の海島構造及び突起部が確認された。
各試料(実施例1~13及び比較例1~7のトナー)の評価方法は、以下の通りである。
試料(トナー)2gを容量20mLのポリ容器に秤量し、60℃に設定された恒温器内に3時間静置した。その結果、耐熱保存性評価用の試料を得た。その後、耐熱保存性評価用の試料を、パウダーテスター(ホソカワミクロン株式会社製)のマニュアルに従い、レオスタッド目盛り5及び時間30秒の条件で、100メッシュ(目開き150μm)の篩を用いて篩別した。篩別後に、篩上に残留した試料の質量を測定した。篩別前の試料の質量と、篩別後に篩上に残留した試料の質量とから、以下の式にしたがってトナーの凝集度(質量%)を算出した。
凝集度(質量%)=(篩上に残留した試料の質量/篩別前の試料の質量)×100
算出された凝集度から、下記基準にしたがってトナーの耐熱保存性を評価した。
○(良い):凝集度が50質量%以下であった。
×(悪い):凝集度が50質量%を超えた。
現像剤用キャリア(京セラドキュメントソリューションズ株式会社製「TASKalfa5550ci」用キャリア)と、キャリアの質量に対して10質量%のトナーとを、ボールミルを用いて30分間混合し、評価用の2成分現像剤を調製した。
○(良い):最低定着温度が160℃以下であった。
×(悪い):最低定着温度が160℃超であった。
試料(トナー)のトナー母粒子に、Cu-Zn系フェライトキャリア(パウダーテック社製「F-80」)を添加して、トナー濃度10質量%の現像剤を調製した。調製した現像剤を室温環境(R/R環境:温度20℃、相対湿度65%RH)下で一晩静置した。静置した現像剤を混合装置(WAB社製「ターブラー(登録商標)ミキサー」)を用いて、3分間混合した。Q/mメーター(トレック社製「MODEL 210HS-2A」)を用いて、3分混合後の現像剤中のトナーの帯電量(以下、3分混合後の帯電量と記載する)を測定した。
現像剤中のトナーの帯電量(μC/g)=吸引されたトナーの総電気量(μC)/吸引されたトナーの質量(g)
帯電立ち上がり割合(%)=(3分混合後の帯電量/30分混合後の帯電量)×100
算出した帯電立ち上がり割合から、下記基準にしたがってトナーの帯電立ち上がり性能を評価した。
○(良い):帯電立ち上がり割合が60%以上であった。
×(悪い):帯電立ち上がり割合が60%未満であった。
試料(トナー)のトナー母粒子に、Cu-Zn系フェライトキャリア(パウダーテック社製「F-80」)を添加して、トナー濃度10質量%トナー粒子の現像剤を調製した。調製した現像剤を室温環境(R/R環境:温度20℃、相対湿度65%RH)下で一晩静置した。静置した現像剤を、混合装置(WAB社製「ターブラー(登録商標)ミキサー」)を用いて、30分間混合した。Q/mメーター(トレック社製「MODEL 210HS-2A」)を用いて、混合後の現像剤中のトナーの帯電量(以下、R/R環境での帯電量と記載する)を測定した。また、調製した現像剤を高温高湿環境(H/H環境:温度32℃、湿度80%RH)下で静置した以外は、R/R環境での帯電量と同様にして、混合後の現像剤中のトナーの帯電量(以下、H/H環境での帯電量と記載する)を測定した。得られたH/H環境での帯電量及びR/R環境での帯電量から、以下の式にしたがって環境帯電量変化率を算出した。
環境帯電量変化率(%)=[(H/H環境での帯電量)÷(R/R環境での帯電量)]×100
○(良い):環境帯電量変化率が80%以上であった。
×(悪い):環境帯電量変化率が80%未満であった。
試料(トナー)0.5gを、内径10mmの錠剤成形器に入れて、80℃に加熱しながら成型した。その結果、薄膜状の測定用試料を得た。測定する直前に測定用試料を前処理(Arエッチング)し、測定用試料の表面の汚染物質を除去した。なお、Arエッチングは、Arガス0.5MPa及び加速電圧1kVの条件で行われた。
・X線源:MgKα
・X線源の電圧電流値:400W
・検量線:清浄なプラスチックフィルム上に既知量のアルカリ金属塩水溶液をスプレーして乾燥させ、測定することで検量線を作成した。
・測定領域(X線照射範囲):直径1mm
・n数:3以上
・PassEnergy:70eV
・StepSize:0.25eV
・測定元素:アルカリ金属元素(ナトリウム、カリウム)
存在量Bの測定でも、上述した存在量Aの測定と同様、前処理された測定用試料を得た。
・X線源:Rh
・X線源の電圧電流値:50kV、50mA
・検量線:トナー粒子の全構成元素についての蛍光X線のNet強度を測定し、検量線を作成した。
・測定領域(X線照射範囲):直径30mm
・n数:3以上
・StepSize:0.050°(2θ)
・測定元素:アルカリ金属元素(ナトリウム、カリウム)
存在量Aを存在量Bで除して、アルカリ金属元素の存在量の比の値A/B(=存在量A/存在量B)を求めた。
各試料(実施例1~13及び比較例1~7のトナー)の各々についての評価結果は以下の通りである。
Claims (9)
- トナーコアと、前記トナーコアの表面を被覆するシェル層とを含むトナー粒子を、複数有する静電潜像現像用トナーであって、
前記シェル層は、疎水性熱可塑性樹脂と、正帯電性を有する親水性非水溶性樹脂とを含み、
X線光電子分光法で測定される前記シェル層の表面層におけるアルカリ金属元素の存在量Aと、蛍光X線法で測定される前記トナー粒子全体におけるアルカリ金属元素の存在量Bとは、以下に示す式(a)及び式(b)を満たす、静電潜像現像用トナー。
A≦300ppm・・・(a)
0.5≦A/B<1.0・・・(b) - 前記存在量Aは以下に示す式(c)を満たす、請求項1に記載の静電潜像現像用トナー。
230ppm<A≦300ppm・・・(c) - 前記存在量Aは以下に示す式(d)を満たす、請求項1に記載の静電潜像現像用トナー。
180ppm<A<230ppm・・・(d) - 前記存在量Aと前記存在量Bとは以下に示す式(e)を満たす、請求項3に記載の静電潜像現像用トナー。
0.8≦A/B≦0.9・・・(e) - 前記トナーコアは粉砕法で作製される、請求項1に記載の静電潜像現像用トナー。
- 前記シェル層は、前記親水性非水溶性樹脂を島とし、前記疎水性熱可塑性樹脂を海とする海島構造を有する、請求項1に記載の静電潜像現像用トナー。
- 前記シェル層は、前記シェル層の表面に突起部を有し、
前記突起部は、実質的に前記親水性非水溶性樹脂から構成される、請求項1に記載の静電潜像現像用トナー。 - 前記疎水性熱可塑性樹脂はスチレン-アクリル酸系共重合体を含み、
前記親水性非水溶性樹脂はアクリル酸系樹脂を含み、
前記アクリル酸系樹脂は、正帯電性の官能基を有するモノマー由来の繰り返し単位を含む、請求項1に記載の静電潜像現像用トナー。 - 請求項1に記載の静電潜像現像用トナーの製造方法であって、
前記トナーコアを粉砕法で作製するトナーコア作製工程と、
水性媒体中で前記トナーコアの表面に前記シェル層を形成するシェル層形成工程と、
前記式(a)及び前記式(b)を満たすように、前記トナー粒子を洗浄液で洗浄する洗浄工程と
を含む、静電潜像現像用トナーの製造方法。
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