Toner for developing electrostatic images and method for manufacturing electrostatic image developing toner

Abstract

To provide a toner which offers superior low-temperature fixability, fixing separability, and charging properties, and to provide a method of manufacturing the same.SOLUTION: A toner provided herein contains a polymer represented by a formula (1) below and a release agent. (In the formula (1), R1 represents a hydrogen atom or alkyl group with 1 to 3 carbon atoms, and R2 and R3 represent a hydrogen atom, alkyl group having 1-3 carbon atoms, or alkoxy group.)SELECTED DRAWING: None

Description

TECHNICAL FIELD

[0001] The present invention relates to a toner for developing electrostatic charge images and a method for producing a toner for developing electrostatic charge images. In particular, the present invention relates to a toner for developing electrostatic charge images that satisfies low-temperature fixability, can cope with increased print output speed, and has excellent charging characteristics. BACKGROUND ART

[0002] Along with the decrease in print volume, demand for digital printing that enables small-lot printing has been increasing in recent years. In the printing business, it is generally important to improve productivity per unit time in order to increase profitability. Similarly, in digital printing, increasing the print output speed can be said to be an indispensable major issue.

[0003] Conventionally, to address such a problem of speed increase, studies have been conducted on low-temperature fixing of toners that can be fixed onto media such as paper with a low amount of energy (see, for example, Patent Documents 1 to 3). Specifically, examples thereof include lowering the glass transition temperature of a toner binder, which is a main toner component, and lowering the melt viscosity by controlling the molecular weight distribution. Lowering the glass transition temperature of a toner binder can be adjusted, for example, by the following method. For styrene-acrylic resins, the glass transition temperature can be adjusted by the ratio of a hard segment formed from a monomer such as styrene and a soft segment formed from a monomer such as n-butyl acrylate. Here, hard segments such as styrene are high glass transition temperature components, and soft segments such as n-butyl acrylate are low glass transition temperature components. Lowering the glass transition temperature can be realized by increasing the ratio of soft segments such as butyl acrylate.

[0004] However, increasing the soft segment ratio increases the adhesion between the toner and the roller in commonly used hot roller fixing. As a result, the image and roller cannot be properly separated during fixing. Consequently, problems such as the image getting caught in the roller and resulting in no print being produced, or the image surface becoming rough and uneven, are known as deterioration of fixation separation.

[0005] To address this problem, release agents such as low-melt-viscosity fatty acid ester waxes have been added to suppress adhesion between the fixing member and the toner (see, for example, Patent Document 4). Such release agents, such as fatty acid ester waxes, seep into the interface between the fixing member and the fixed image during fixing, thereby suppressing the aforementioned adhesion. However, even when a low-melt-viscosity release agent was added, it was often difficult to ensure sufficient release properties when the proportion of soft segments was high. Furthermore, while increasing the soft segment ratio enables the low-temperature fixing described above, it also presents problems other than those related to fixing and separation. Specifically, when using n-butyl acrylate, a common monomer, the dielectric loss tangent (tanδ), an indicator of charge leakage, is high in the charging characteristics required for toner. This results in a problem of low charge retention. Furthermore, poor charge retention leads to a low charge level in the toner, and especially at high print output speeds, the toner cannot obtain sufficient charge. As a result, problems such as in-machine contamination due to toner scattering and image defects become apparent. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2007-279714 [Patent Document 2] Japanese Patent Publication No. 2008-287229 [Patent Document 3] Japanese Patent Publication No. 2010-15159 [Patent Document 4] Japanese Patent Application Publication No. 8-50368 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] This invention was made in view of the above-mentioned problems and circumstances. The problem to be solved is to provide a toner for developing electrostatic images and a method for manufacturing the same, which has excellent charging characteristics while satisfying low-temperature fixing properties and fixing separation properties. [Means for solving the problem]

[0008] To solve the above problems, the inventors have found it important to include a polymer having a specific structural unit as a binder resin, and also to include a release agent. This makes it possible to provide a toner for electrostatic image development with excellent charging properties that can suppress in-machine contamination such as toner scattering while satisfying low-temperature fixing properties and fixing separation properties. In other words, the above-mentioned problems according to the present invention are solved by the following means.

[0009] 1. A toner for electrostatic image development containing toner particles, The toner particles are polymers having structural units represented by general formula (1). It contains as a binder resin, and Contains a release agent. A toner for developing electrostatic images, characterized by the following features. [ka] [In the general formula (1) above, R1 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R2 and R3 each independently represent a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group.]

[0010] 2. The release agent is a fatty acid ester using a fatty acid having 16 to 24 carbon atoms. The electrostatic image developing toner according to the first paragraph, characterized in that...

[0011] 3. In the above general formula (1), R1 is a hydrogen atom or a methyl group, and R2 and R3 are each independently a hydrogen atom or a methoxy group The toner for developing electrostatic latent images according to item 1, characterized in that:

[0012] 4. In the above general formula (1), R2 and R3 are hydrogen atoms The toner for developing electrostatic latent images according to item 1, characterized in that:

[0013] 5. The polymer having a structural unit represented by the above general formula (1) is a copolymer of a first polymerizable monomer having a structure represented by the following general formula (2) and another polymerizable monomer copolymerizable with the first polymerizable monomer The toner for developing electrostatic latent images according to item 1, characterized in that:

Chemical Formula

[0014] 6. The content of the structural unit derived from the first polymerizable monomer is in the range of 10 to 35% by mass relative to the total structural units (100% by mass) constituting the polymer having the structural unit represented by the general formula (1) The toner for developing electrostatic latent images according to item 5, characterized in that:

[0015] 7. The other polymerizable monomer is at least selected from the group consisting of styrenes, acrylic acid, methacrylic acid, acrylic acid esters, and methacrylic acid esters The toner for developing electrostatic latent images according to item 5, characterized in that:

[0016] 8. The other polymerizable monomer is one or more selected from the group consisting of styrene, acrylic acid, n-butyl acrylate, iso-butyl acrylate, 2-ethylhexyl acrylate, and methacrylic acid The electrostatic image developing toner according to paragraph 7, characterized in that...

[0017] 9. The fatty acid ester using a fatty acid having 16 to 24 carbon atoms is behenyl behenate. The electrostatic image developing toner according to paragraph 2, characterized in that it is a toner for developing electrostatic images.

[0018] 10. The fatty acid ester using a fatty acid having 16 to 24 carbon atoms is pentaerythritol tetrabehenate. The electrostatic image developing toner according to paragraph 2, characterized in that it is a toner for developing electrostatic images.

[0019] 11. The fatty acid ester using a fatty acid having 16 to 24 carbon atoms is ethylene glycol distearate ester. The electrostatic image developing toner according to paragraph 2, characterized in that it is a toner for developing electrostatic images.

[0020] 12. The content of fatty acid esters using fatty acids having 16 to 24 carbon atoms in the toner for developing electrostatic images is within the range of 5 to 20% by mass. The electrostatic image developing toner according to paragraph 2, characterized in that it is a toner for developing electrostatic images.

[0021] 13. A method for manufacturing a toner for electrostatic image development as described in any one of paragraphs 1 to 12, The process includes a step of polymerizing a first polymerizable monomer having a structure represented by the following general formula (2) to prepare a toner binder particle dispersion containing the mold release agent. A method for manufacturing toner for electrostatic image developing, characterized by the features described above. [ka] [In the general formula (2) above, R1 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R2 and R3 each independently represent a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group.]

[0022] 14. A method for manufacturing a toner for electrostatic image development as described in any one of paragraphs 2 to 12, Polymerization of a first polymerizable monomer having the structure represented by the following general formula (2) is performed. charcoal The process includes a step of preparing a toner binder particle dispersion containing a fatty acid ester made from a fatty acid within the prime number range of 16 to 24 as a mold release agent. A method for manufacturing toner for electrostatic image developing, characterized by the features described above. [ka] [In the general formula (2) above, R1 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R2 and R3 each independently represent a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group.]

[0023] 15. The fatty acid ester using a fatty acid having 16 to 24 carbon atoms is behenyl behenate. A method for manufacturing toner for electrostatic image developing according to paragraph 14, characterized by the above.

[0024] 16. The fatty acid ester using a fatty acid having 16 to 24 carbon atoms is pentaerythritol tetrabehenate. A method for manufacturing toner for electrostatic image developing according to paragraph 14, characterized by the above.

[0025] 17. The fatty acid ester using a fatty acid having 16 to 24 carbon atoms is ethylene glycol distearate ester. A method for manufacturing toner for electrostatic image developing according to paragraph 14, characterized by the above. [Effects of the Invention]

[0026] The above-described means of the present invention makes it possible to provide an electrostatic image developing toner with excellent charging characteristics that can suppress in-machine contamination such as toner scattering while satisfying low-temperature fixing properties and fixing separation properties, as well as a method for manufacturing the same. The mechanism of action or mechanism of the present invention is not yet clear, but it is speculated to be as follows. It should be noted that the following mechanism is speculative, and the present invention is not limited in any way to this mechanism. In the following description, a polymer having the structural unit represented by the general formula (1) will also be simply referred to as "the polymer according to the present invention."

[0027] The toner of the present invention satisfies low-temperature fixing properties and fixing / separation properties while exhibiting excellent electrostatic properties that suppress in-machine contamination such as toner scattering. This is presumed to be due to the interaction between the polymer of the present invention and the release agent, and the low charge leakage of the polymer of the present invention. By introducing the polymer according to the present invention into toner particles, the solubility parameter is increased, which reduces compatibility with the release agent (i.e., makes it incompatible). The reduced compatibility minimizes interaction with the polymer according to the present invention, allowing it to quickly seep between the image and the fixing roller during fixing. Therefore, it can be inferred that good fixing separation can be ensured even when the soft segment ratio is increased and the glass transition temperature is lowered. Furthermore, by introducing the polymer according to the present invention into toner particles, it becomes possible to keep the dielectric loss tangent (tanδ), which is an indicator of charge leakage, low. By keeping tanδ low, it is possible to increase the absolute value of the charge. Furthermore, at higher print output speeds, the toner can acquire a sufficient charge. As a result, it can be inferred that in-machine contamination due to toner scattering and the occurrence of image defects can be suppressed. [Brief explanation of the drawing]

[0028] [Figure 1] This figure shows the apparatus used to measure the amount of charge in the example. [Modes for carrying out the invention]

[0029] The electrostatic image developing toner of the present invention is an electrostatic image developing toner containing toner particles, characterized in that the toner particles contain a polymer having a structural unit represented by the general formula (1) and a mold release agent. This feature is a technical feature common to or corresponding to each of the embodiments described below.

[0030] In embodiments of the present invention, it is preferable that the release agent is a fatty acid ester using a fatty acid having 16 to 24 carbon atoms, in terms of its interaction with the polymer according to the present invention.

[0031] In the above general formula (1), it is preferable that R1 is a hydrogen atom or a methyl group, and that R2 and R3 are each independently a hydrogen atom or a methoxy group, in order to achieve both low-temperature fixability and fixation separation properties.

[0032] In the above general formula (1), it is preferable that R2 and R3 are hydrogen atoms in terms of low-temperature fixability, fixation separation, and chargeability.

[0033] Preferably, the content of structural units derived from the first polymerizable monomer is within the range of 10 to 35% by mass relative to the total structural units (100% by mass) constituting the polymer having the structural units represented by the general formula (1). This allows for a sufficient amount of charge to be obtained while maintaining both low-temperature fixability and fixation separation properties.

[0034] It is preferable that the other polymerizable monomer is selected from the group consisting of at least styrenes, acrylic acid, methacrylic acid, acrylic acid esters, and methacrylic acid esters. In particular, it is preferable that the other polymerizable monomer is selected from one or more of styrene, acrylic acid, n-butyl acrylate, iso-butyl acrylate, 2-ethylhexyl acrylate, and methacrylic acid. This is preferable because it facilitates the adjustment of the glass transition temperature of the polymer according to the present invention.

[0035] It is preferable that the fatty acid ester using a fatty acid having 16 to 24 carbon atoms is behenyl behenate, in terms of low-temperature fixation and fixation separation properties. It is preferable that the fatty acid ester using a fatty acid having 16 to 24 carbon atoms is pentaerythritol tetrabehenate ester, in terms of low-temperature fixation and fixation separation properties. It is preferable that the fatty acid ester using a fatty acid having 16 to 24 carbon atoms is ethylene glycol distearate ester, in terms of low-temperature fixation and fixation separation properties.

[0036] It is preferable that the content of fatty acid esters using fatty acids with 16 to 24 carbon atoms in the toner for developing electrostatic images is within the range of 5 to 20% by mass. By having the content within this range, it is possible to achieve both low-temperature fixing properties and fixing separation properties.

[0037] A method for producing electrostatic image developing toner in one embodiment of the present invention is characterized by comprising the steps of polymerizing a first polymerizable monomer having the structure represented by the general formula (2) above, and preparing a toner binder particle dispersion containing the mold release agent. This makes it possible to produce toner that achieves both low-temperature fixing properties and fixing separation properties while obtaining a sufficient amount of charge.

[0038] Furthermore, another embodiment of the present invention provides a method for producing toner for electrostatic image development, characterized by comprising the step of polymerizing a first polymerizable monomer having the structure represented by the general formula (2), and preparing a toner binder particle dispersion containing a fatty acid ester using a fatty acid having 16 to 24 carbon atoms as a release agent. This makes it possible to produce toner that achieves both low-temperature fixing properties and fixing separation properties while obtaining a sufficient amount of charge.

[0039] The present invention, its components, and embodiments for carrying out the present invention will be described below. In this application, "~" is used to mean that the numerical values ​​written before and after it are included as the lower limit and upper limit.

[0040] [Toner for electrostatic image development according to the present invention] The electrostatic image developing toner of the present invention (hereinafter also simply referred to as "toner") is an electrostatic image developing toner containing toner particles, characterized in that the toner particles contain a polymer having a structural unit represented by the following general formula (1) and a mold release agent.

[0041] In this specification, "toner matrix particles" refer to the components that make up the matrix of "toner particles." "Toner matrix particles" include at least a toner binder and a release agent, and may also contain other components such as colorants and charge control agents as needed. "Toner matrix particles" are referred to as "toner particles" when external additives are added. And "toner" refers to an aggregate of "toner particles."

[0042] <Polymers having structural units represented by general formula (1)> The toner according to the present invention contains a polymer having a structural unit represented by the following general formula (1) (the polymer according to the present invention). The polymer according to the present invention is preferably included as a toner binder.

[0043] [ka]

[0044] In the general formula (1) above, R1 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R2 and R3 each independently represent a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group. Specific examples include, for instance, R1 being a hydrogen atom, methyl group, ethyl group, n-propyl group, or iso-propyl group. R2 and R3 being a hydrogen atom, methyl group, ethyl group, n-propyl group, iso-propyl group, methoxy group, ethoxy group, n-propoxy group, or iso-propoxy group. From the viewpoint of achieving both low-temperature fixation and fixation separation while obtaining a sufficient amount of charge, R1 is preferably a hydrogen atom or a methyl group. R2 and R3 are preferably a hydrogen atom, a methyl group, or a methoxy group.

[0045] The polymer according to the present invention can be synthesized by polymerizing a monomer having a structure represented by the following general formula (2) (hereinafter also referred to as the "first polymerizable monomer"). [ka]

[0046] In the general formula (2) above, R1 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R2 and R3 each independently represent a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group. R1, R2, and R3 are equivalent to R1R2 and R3 in the general formula (1) above, respectively.

[0047] The first polymerizable monomer can be used alone or in combination of two or more types. Specific examples of the first polymerizable monomer mentioned above include the following exemplary compounds M1 to M12, but the present invention is not limited to these.

[0048] [ka]

[0049] The first polymerizable monomer may be a commercially available product or a synthetic product. As an example of a method for synthesizing the first polymerizable monomer, the first polymerizable monomer can also be obtained by a condensation reaction between (meth)acrylic acid and a predetermined alcohol as a starting material.

[0050] Preferably, the content of structural units derived from the first polymerizable monomer is in the range of 5 to 50% by mass relative to the total structural units (100% by mass) constituting the polymer according to the present invention. More preferably, the content is in the range of 10 to 35% by mass.

[0051] The polymerization method for the first polymerizable monomer is not particularly limited. However, from the viewpoint of easy synthesis, a method of radical polymerization of the monomer using a known oil-soluble or water-soluble radical polymerization initiator is preferred. In other words, a preferred embodiment of the present invention is a method for producing toner for electrostatic image development, comprising a toner binder containing the polymer according to the present invention and a release agent. The method comprises the steps of synthesizing the polymer according to the present invention by (radical) polymerization of a polymerizable monomer having the structure represented by the general formula (2), and mixing the toner binder and the release agent.

[0052] Oil-soluble polymerization initiators used in radical polymerization include, specifically, the azo-based or diazo-based polymerization initiators and peroxide-based polymerization initiators listed below. If necessary, known chain transfer agents such as n-octyl mercaptan and n-octyl-3-mercaptopropionate may be used.

[0053] Examples of azo or diazo polymerization initiators include 2,2'-azobis-(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis(cyclohexane-1-carbonitride), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, and azobisisobutyronitrile.

[0054] Examples of peroxide-based polymerization initiators include benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide, dicumyl peroxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, 2,2-bis-(4,4-t-butylperoxycyclohexyl)propane, and tris-(t-butylperoxy)triazine.

[0055] Furthermore, when forming the polymer according to the present invention by emulsion polymerization, a water-soluble radical polymerization initiator can be used. Examples of water-soluble radical polymerization initiators include persulfates such as potassium persulfate and ammonium persulfate, azobisaminodipropane acetate, azobiscyanovaleric acid and its salts, and hydrogen peroxide.

[0056] The polymerization temperature varies depending on the type of monomer and polymerization initiator used, but it is preferably in the range of 50 to 100°C, and more preferably in the range of 55 to 90°C. Furthermore, the polymerization time varies depending on the type of monomer and polymerization initiator used, but it is preferably 1 to 12 hours, for example.

[0057] <Polymers with other structural units> The polymer according to the present invention may be a polymer obtained solely from a polymerizable monomer having the structure represented by the general formula (2) (the first polymerizable monomer). However, from the viewpoint of exhibiting the effects of the present invention more efficiently, it is preferable that the first polymerizable monomer is copolymerized with another polymerizable monomer (also called the "second polymerizable monomer") as described below.

[0058] Examples of the second polymerizable monomer include styrene-based monomers such as styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o-ethylstyrene, m-ethylstyrene, p-ethylstyrene, o-acetoxystyrene, m-acetoxystyrene, and p-acetoxystyrene; Acrylic acid esters such as methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, tert-butyl acrylate, isobutyl acrylate (iso-butyl acrylate), n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, and phenyl acrylate; Methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate (iso-butyl methacrylate), tert-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, and diethylaminoethyl methacrylate; Examples include acrylic acid and methacrylic acid. Among these, at least one selected from styrenes, acrylic acid esters, and methacrylic acid esters is preferred. Furthermore, it is preferable to select one or more from styrene, acrylic acid, n-butyl acrylate, iso-butyl acrylate, 2-ethylhexyl acrylate, and methacrylic acid. Moreover, at least one of styrene and n-butyl acrylate is preferred. Using such monomers makes it easier to adjust the glass transition temperature of the polymer.

[0059] Furthermore, a polymerizable monomer having an ionic dissociation group may be used as the second polymerizable monomer. Polymerizable monomers having ionic dissociable groups include, for example, those having groups such as carboxyl groups, sulfonic acid groups, and phosphate groups. Specifically, examples include acrylic acid, methacrylic acid, maleic acid, itaconic acid, and fumaric acid. Of these, acrylic acid or methacrylic acid are preferred. These second polymerizable monomers can be used individually or in combination of two or more.

[0060] In the polymer according to the present invention, the content of structural units derived from the second polymerizable monomer is not particularly limited and can be appropriately adjusted depending on the type of structural unit. For example, when the second polymerizable monomer is the styrene-based monomer described above, the content of structural units derived from the styrene-based monomer in the polymer is preferably in the range of 20 to 80% by mass. More preferably, it is in the range of 30 to 70% by mass. Here, the above content is defined as 100% by mass of all structural units constituting the polymer according to the present invention.

[0061] When the second polymerizable monomer is an acrylic acid ester or a methacrylic acid ester, the content of structural units derived from the acrylic acid ester or methacrylic acid ester in the polymer is preferably in the range of 5 to 50% by mass. More preferably, it is in the range of 10 to 40% by mass. Here, the above content is defined as 100% by mass of all structural units constituting the polymer according to the present invention.

[0062] When using polymerizable monomers having ionic dissociation groups, the content of their structural units is preferably in the range of 3 to 8% by mass. Here, the content is defined as 100% by mass of all structural units constituting the polymer according to the present invention.

[0063] The method for synthesizing the polymer according to the present invention using the first polymerizable monomer and the second polymerizable monomer is the same as the polymerization method for the first polymerizable monomer described above, so the explanation is omitted here.

[0064] The polymer according to the present invention preferably has a peak molecular weight in the range of 3500 to 35000, obtained from the molecular weight distribution in polystyrene equivalent as measured by gel permeation chromatography (GPC). More preferably, it is in the range of 10000 to 30000. A peak molecular weight in this range is preferable because it allows the polymer to achieve an appropriate melt viscosity during fixation, enabling both good fixation and fixation separation properties. Peak molecular weight refers to the molecular weight corresponding to the elution time of the peak top in the molecular weight distribution. If multiple peaks exist in the molecular weight distribution, it refers to the molecular weight corresponding to the elution time of the peak top with the largest peak area ratio.

[0065] The peak molecular weight of a polymer can be measured by the following method. Specifically, the instrument "HLC-8220" (manufactured by Tosoh Corporation) and the column "TSKguardcolumn+TSKgelSuperHZM-M3" (manufactured by Tosoh Corporation) are used. Then, while maintaining the column temperature at 40°C, tetrahydrofuran (THF) is flowed as the carrier solvent at a flow rate of 0.2 ml / min. The sample to be measured is dissolved in tetrahydrofuran to a concentration of 1 mg / ml under dissolution conditions that involve processing with an ultrasonic disperser for 5 minutes at room temperature (25°C). Next, the sample solution is obtained by processing it through a membrane filter with a pore size of 0.2 μm. 10 μL of this sample solution is injected into the apparatus together with the carrier solvent mentioned above, detected using a refractive index detector (RI detector), and the molecular weight distribution of the sample is measured.

[0066] The content of the polymer according to the present invention is preferably in the range of 65 to 99% by mass, with the total mass of the polymer according to the present invention being 100% by mass. More preferably, it is in the range of 70 to 97% by mass, and even more preferably, in the range of 75 to 95% by mass. By setting the content within the above range, a good balance between low-temperature fixability and fixation separation properties is achieved.

[0067] The toner binder according to the present invention may contain resins other than the polymer according to the present invention. The other resins can be any resin commonly used as toner binders that constitute toner, without limitation. Specifically, examples include polyester resin, silicone resin, polyolefin resin, polyamide resin, or epoxy resin. These other resins can be used individually or in combination of two or more.

[0068] The following describes polyester resins that can be used as toner binders. (Polyester resin) Polyester resin is a known polyester resin obtained by a polycondensation reaction between a divalent or higher carboxylic acid (polyvalent carboxylic acid component) and a divalent or higher alcohol (polyvalent alcohol component). The polyester resin may be amorphous or crystalline.

[0069] The valencies of the polycarboxylic acid component and the polyhydric alcohol component are preferably 2 to 3, and particularly preferably 2. Therefore, the case where the valency of each component is 2 (i.e., the dicarboxylic acid component and the diol component) will be described as a particularly preferred form.

[0070] Examples of dicarboxylic acid components include saturated aliphatic compounds such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid (dodecanediic acid), 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,16-hexadecanedicarboxylic acid, and 1,18-octadecanedicarboxylic acid. Examples include dicarboxylic acids; unsaturated aliphatic dicarboxylic acids such as methylene succinic acid, fumaric acid, maleic acid, 3-hexenedioic acid, 3-octenedioic acid, and dodecenyl succinic acid; and unsaturated aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, t-butylisophthalic acid, tetrachlorophthalic acid, chlorophthalic acid, nitrophthalic acid, p-phenylenediacetic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, and anthracenedicarboxylic acid. Lower alkyl esters and acid anhydrides of these can also be used. The dicarboxylic acid components may be used individually or in combination of two or more. In addition, polycarboxylic acids with a valency of 3 or higher, such as trimellitic acid and pyromellitic acid, as well as anhydrides of the above carboxylic acid compounds, or alkyl esters having 1 to 3 carbon atoms, can also be used.

[0071] Examples of diol components include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, and 1,20-eicosa Examples include saturated aliphatic diols such as diols and neopentyl glycol; unsaturated aliphatic diols such as 2-butene-1,4-diol, 3-butene-1,4-diol, 2-butyne-1,4-diol, 3-butyne-1,4-diol, and 9-octadecene-7,12-diol; and aromatic diols such as bisphenols like bisphenol A and bisphenol F, and alkylene oxide adducts of bisphenols such as ethylene oxide adducts and propylene oxide adducts. Derivatives of these can also be used. The diol components may be used individually or in combination of two or more.

[0072] The method for producing the polyester resin is not particularly limited. The production method involves polycondensing (esterifying) the polycarboxylic acid component and the polyhydric alcohol component using a known esterification catalyst.

[0073] Catalysts that can be used in the production of polyester resins include alkali metal compounds such as sodium and lithium; compounds containing group 2 elements such as magnesium and calcium; metal compounds such as aluminum, zinc, manganese, antimony, titanium, tin, zirconium, and germanium; phosphite compounds; phosphate compounds; and amine compounds. Specifically, tin compounds include dibutyltin oxide, tin octoate, tin dioctoate, and their salts.

[0074] Examples of titanium compounds include titanium alkoxides such as tetran-butyl titanate (Ti(On-Bu)4), tetraisopropyl titanate, tetramethyl titanate, and tetrastearyl titanate; titanium acylates such as polyhydroxytitanium stearate; and titanium chelates such as titanium tetraacetylacetonate, titanium lactate, and titanium triethanolamine. Examples of germanium compounds include germanium dioxide. Furthermore, examples of aluminum compounds include polyaluminum hydroxide, aluminum alkoxide, and tributylaluminate. These may be used individually or in combination of two or more.

[0075] The polymerization temperature is not particularly limited, but is preferably in the range of 70 to 250°C. Similarly, the polymerization time is not particularly limited, but is preferably 0.5 to 10 hours. During polymerization, the reaction system may be subjected to reduced pressure as needed. The above-mentioned polyester resin may be a hybrid polyester resin having a graft copolymer structure of a polyester polymerization segment and a styrene-acrylic polymerization segment graft.

[0076] The content of the polymer according to the present invention in the toner binder is preferably in the range of 5 to 50% by mass, and more preferably in the range of 10 to 35% by mass, with the total mass of the binder resin being 100% by mass.

[0077] <Release agent> The toner matrix particles according to the present invention contain a release agent. Examples of fatty acid esters contained in mold release agents include, for example, behenyl behenate (behenyl behenate), stearyl stearate (stearyl stearate), behenyl stearate, stearyl behenate, butyl stearate, propyl oleate, hexadecyl palmitate (hexadecyl palmitate), methyl lignocerate (methyl lignocerate), glyceryl monostearate (glyceryl stearate), diglyceryl distearate (diglyceryl distearate), and pentaerythritol. Examples include tetrabehenate (pentaerythritol tetrabehenate), diethylene glycol monostearate, dipropylene glycol distearate, sorbitan monostearate, cholesteryl stearate, trimethylolpropane tribehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, tristearyl trimellitate (tristearyl trimellitate), distearyl maleate, and methyl triacontanate (methyl triacontanoate). These fatty acid esters can be used individually or in combination of two or more.

[0078] Furthermore, these fatty acid esters may be commercially available or synthetically produced. From the viewpoint of interaction with polymers according to the present invention, it is preferable that the fatty acid ester includes fatty acid esters with a carbon number in the range of 16 to 24. Examples of such fatty acids include stearic acid, arachidic acid, behenic acid, and lignoceric acid. A more preferred release agent is at least one of behenyl behenate (behenyl behenate, fatty acid ester with 22 carbon atoms) and pentaerythritol tetrabehenate (pentaerythritol tetrabehenate, fatty acid ester with 22 carbon atoms), ethylene glycol distearate (ethylene glycol distearate, fatty acid ester with 18 carbon atoms), methyl lignocerate (fatty acid ester with 24 carbon atoms), or hexadecyl palmitate (fatty acid ester with 16 carbon atoms). In particular, behenyl behenate (behenyl behenate), pentaerythritol tetrabehenate, or ethylene glycol distearate are preferred.

[0079] The aforementioned release agent may contain waxes other than fatty acid esters. Other examples of such waxes include, for instance, polyolefin waxes such as low molecular weight polyethylene and low molecular weight polypropylene, branched hydrocarbon waxes such as microcrystalline wax, long-chain hydrocarbon waxes such as paraffin wax and sazole wax, dialkylketone waxes such as distearyl ketone, and fatty acid amide waxes such as ethylenediamine behenylamide and trimellitic acid tristearylamide.

[0080] From the viewpoint of balancing fixation and offset resistance, the content of the release agent is preferably in the range of 1 to 25% by mass, with the total mass of the polymer according to the present invention being 100% by mass. More preferably, it is in the range of 5 to 20% by mass.

[0081] The toner matrix particles used in this invention may contain a colorant and a charge control agent as needed. <Coloring agent> The toner matrix particles according to the present invention may contain a colorant. Generally known dyes and pigments can be used as the colorant. Examples of colorants used to obtain black toner include carbon black, magnetic materials, and iron-titanium composite oxide black. Examples of carbon black include channel black, furnace black, acetylene black, thermal black, and lamp black. Examples of magnetic materials include ferrite and magnetite.

[0082] Examples of colorants for obtaining yellow toner include dyes such as CI Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, and 162; and pigments such as CI Pigment Yellow 14, 17, 74, 93, 94, 138, 155, 180, and 185.

[0083] Examples of colorants for obtaining magenta toner include dyes such as CI Solvent Red 1, 49, 52, 58, 63, 111, and 122; and pigments such as CI Pigment Red 5, 48:1, 53:1, 57:1, 122, 139, 144, 149, 166, 177, 178, and 222.

[0084] Examples of colorants for obtaining cyan toner include dyes such as CI Solvent Blue 25, 36, 60, 70, 93, and 95; and pigments such as CI Pigment Blue 1, 7, 15, 60, 62, 66, and 76.

[0085] For each color toner, one or more colorants can be used in combination to obtain the respective color toner. The proportion of colorant is preferably in the range of 0.5 to 20% by mass, and more preferably in the range of 2 to 10% by mass, based on 100% by mass of the total mass of the toner.

[0086] <Charge control agent> The toner matrix particles according to the present invention may contain a charge control agent. The charge control agent used is a substance that can be positively or negatively charged by triboelectric charging and is colorless, but is not particularly limited. Therefore, various known positively charged and negatively charged charge control agents can be used as the charge control agent.

[0087] Specifically, examples of positively charged charge control agents include nigrosine-based dyes such as "Nigrosine Base EX" (manufactured by Orient Chemical Industry Co., Ltd.), quaternary ammonium salts such as "Quaternary Ammonium Salt P-51" (manufactured by Orient Chemical Industry Co., Ltd.) and "Copy Charge PX VP435" (manufactured by Hoechst Japan Co., Ltd.), alkoxylated amines, alkylamides, molybdate chelate pigments, and imidazole compounds such as "PLZ1001" (manufactured by Shikoku Chemicals Co., Ltd.).

[0088] Furthermore, examples of negatively charged charge control agents include metal complexes such as "Bontron® S-22", "Bontron® S-34", "Bontron® E-81", and "Bontron® E-84" (all manufactured by Orient Chemical Industry Co., Ltd.), and "Spiron Black TRH" (manufactured by Hodogaya Chemical Co., Ltd.), thioindigo pigments, quaternary ammonium salts such as "Copy Charge NX VP434" (manufactured by Hoechst Japan), calixarene compounds such as "Bontron® E-89" (manufactured by Orient Chemical Industry Co., Ltd.), boron compounds such as "LR147" (manufactured by Nippon Carlit Co., Ltd.), and fluorine compounds such as magnesium fluoride and carbon fluoride.

[0089] In addition to those listed above, metal complexes with various structures, such as oxycarboxylic acid metal complexes, dicarboxylic acid metal complexes, amino acid metal complexes, diketone metal complexes, diamine metal complexes, azo group-containing benzene-benzene derivative skeleton metal complexes, and azo group-containing benzene-naphthalene derivative skeleton metal complexes, can be used as negatively charged charge control agents. By configuring the toner matrix particles to contain a charge control agent in this way, the chargeability of the toner is improved.

[0090] The content of the charge control agent in the toner is preferably in the range of 0.01 to 30% by mass, and more preferably in the range of 0.1 to 10% by mass.

[0091] The morphology of the toner matrix particles according to the present invention is not particularly limited and can take the form of, for example, a so-called single-layer structure, a core-shell structure, a multilayer structure of three or more layers, a domain-matrix structure, etc. The single-layer structure refers to a homogeneous structure that is not of the core-shell type.

[0092] <External additives> The toner of the present invention may be constructed by adding external additives, such as fluidizers and cleaning aids, which are so-called post-treatment agents, to the toner matrix particles. By adding such external additives, the fluidity, chargeability, cleaning properties, etc., of the toner can be improved.

[0093] Examples of external additives include inorganic oxide particles such as silica particles, alumina particles, and titanium oxide particles; inorganic stearic acid compound particles such as aluminum stearate particles and zinc stearate particles; and inorganic titanate compound particles such as strontium titanate particles and zinc titanate particles. These can be used individually or in combination of two or more types.

[0094] These inorganic particles may be surface-treated with silane coupling agents, titanium coupling agents, higher fatty acids, silicone oils, etc., to improve heat resistance and environmental stability. The amount of external additive added is preferably in the range of 0.05 to 5 parts by mass, and more preferably in the range of 0.1 to 3 parts by mass, per 100 parts by mass of toner matrix particles.

[0095] <Average toner particle size> The average particle size of the toner is preferably in the range of 4 to 10 μm, and more preferably in the range of 5 to 9 μm, based on the volume-based median diameter (D50). Having the volume-based median diameter (D50) within this range increases transfer efficiency, improves halftone image quality, and enhances the image quality of fine lines and dots.

[0096] In this invention, the volume-based median diameter (D50) of the toner is measured and calculated using a measuring device that connects a "Coulter Counter 3" (manufactured by Beckman Coulter, Inc.) to a computer system (manufactured by Beckman Coulter, Inc.) equipped with data processing software "Software V3.51".

[0097] Specifically, 0.02 g of the sample (toner) is added to 20 mL of surfactant solution and mixed in. The surfactant solution is, for example, a surfactant solution obtained by diluting a neutral detergent containing surfactant components 10 times with pure water, for the purpose of dispersing the toner particles. Next, ultrasonic dispersion is performed for 1 minute to prepare the toner dispersion. This toner dispersion is then pipetted into the beaker containing "ISOTONII" (manufactured by Beckman Coulter, Inc.) in the sample stand until the concentration displayed on the measuring device reaches 8%. By using this concentration range, reproducible measurements can be obtained. In the measuring device, the number of particles to be measured is set to 25,000, the aperture diameter to 50 μm, and the measurement range of 1 to 30 μm is divided into 256 parts to calculate frequency values. Then, the particle diameter of the 50% with the largest integrated volume fraction is defined as the volume-based median diameter (D50).

[0098] [Toner manufacturing method] The toner manufacturing method of the present invention is characterized by comprising the steps of polymerizing a first polymerizable monomer having the structure represented by the general formula (2) above, and preparing a toner binder particle dispersion containing the mold release agent. Furthermore, the toner manufacturing method of the present invention only needs to include a step of preparing the toner binder particle dispersion, and is not particularly limited in any other respect. For example, the polymer, release agent, and optionally a coloring agent according to the present invention can be melt-kneaded, and then pulverized, classified, etc., to obtain toner.

[0099] Furthermore, polymer particles are prepared from polymerizable monomers by emulsion polymerization, miniemulsion polymerization, etc., in an aqueous medium. Then, toner can be obtained by an emulsification and agglomeration method in which dispersed particles such as polymer particles, release agent particles, and optionally colorant particles are aggregated and fused together.

[0100] As an emulsification and coagulation method, methods described in Japanese Patent Publication No. 5-265252, Japanese Patent Publication No. 6-329947, Japanese Patent Publication No. 9-15904, etc., can be employed. Furthermore, the manufacturing method may also be one using the suspension polymerization method described in Japanese Patent Publication No. 2010-191043. In particular, a manufacturing method utilizing emulsification and coagulation is preferred because it allows for easy control of particle size and shape, and reduces energy costs during production.

[0101] A manufacturing method utilizing such an emulsification and coagulation method preferably includes the following steps. (1A) Toner binder particle dispersion preparation process for preparing a toner binder particle dispersion. (1B) Process for preparing a dispersion of colorant particles (1C) Preparation of a release agent particle dispersion step (2) Association process in which a flocculant is added to an aqueous medium containing toner binder particles, colorant particles and release agent particles, and salting out occurs while simultaneously causing aggregation and fusion to form associated particles. (3) A maturation process in which toner particles are formed by controlling the shape of associated particles. (4) Filtration and washing process to separate toner particles from an aqueous medium and remove surfactants, etc. from the toner particles. (5) Drying process to dry the washed toner particles (6) Addition of external additives to the dried toner particles

[0102] The following describes steps (1A) to (1C). (1A) Preparation process for toner binder particle dispersion In this process, resin particles are formed by conventional emulsion polymerization or other known methods, and these resin particles are aggregated and fused together to form binder resin particles. As an example, polymerizable monomers constituting the binder resin (the first polymerizable monomer and the second polymerizable monomer) are added to and dispersed in an aqueous medium, and these polymerizable monomers are polymerized using a polymerization initiator. This produces a dispersion of binder resin particles.

[0103] In addition to the method of polymerizing polymerizable monomers with a polymerization initiator in the aqueous medium described above, there are other methods for obtaining toner binder particle dispersions. For example, there is a method of performing dispersion treatment in an aqueous medium without using a solvent. Alternatively, one method involves dissolving the polymer in an organic solvent such as ethyl acetate to make a solution, emulsifying and dispersing the solution in an aqueous medium using a disperser, and then performing a solvent removal treatment.

[0104] In this case, a mold release agent may be pre-included in the toner binder as needed. Furthermore, polymerization in the presence of a known surfactant is also preferable for dispersion. Examples of the known surfactants include anionic surfactants such as sodium polyoxyethylene(2) dodecyl ether sulfate, sodium dodecyl sulfate, and sodium dodecylbenzenesulfonate.

[0105] The volume-based median diameter of toner binder particles in the dispersion is preferably in the range of 50 to 300 nm. The volume-based median diameter of binder resin particles in the dispersion can be measured by dynamic light scattering using "Microtrac UPA-150" (manufactured by Nikkiso Co., Ltd.).

[0106] (1B) Preparation of colorant particle dispersion This colorant particle dispersion preparation process involves dispersing a colorant in an aqueous medium in the form of fine particles to prepare a dispersion of colorant particles. The dispersion of the colorant can be carried out using mechanical energy. The volume-based median diameter of the colorant particles in the dispersion is preferably in the range of 10 to 300 nm, and more preferably in the range of 50 to 200 nm. The volume-based median diameter of the colorant particles in the dispersion can be measured by dynamic light scattering using the "Microtrac UPA-150" (manufactured by Nikkiso Co., Ltd.), as described above.

[0107] (1C) Preparation of mold release agent particle dispersion process This mold release agent particle dispersion preparation process involves dispersing the mold release agent in a fine particle form in an aqueous medium to prepare a dispersion of mold release agent particles. The dispersion of the mold release agent can be performed using mechanical energy. The volume-based median diameter of the release agent particles in the dispersion is preferably in the range of 100 to 1000 nm, and more preferably in the range of 200 to 700 nm. The volume-based median diameter of release agent particles in a dispersion can be measured, for example, using a laser diffraction particle size distribution analyzer LA-750 (manufactured by Horiba, Ltd.).

[0108] (aqueous medium) The aqueous media used in steps (1A) to (1C) include water, or an aqueous media mainly composed of water (50% by mass or more) with water-soluble solvents such as alcohols and glycols, or optional components such as surfactants and dispersants. Preferably, the aqueous media is a mixture of water and a surfactant.

[0109] Examples of the above-mentioned water-soluble solvents include methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, and tetrahydrofuran. Of these, alcohols such as methanol, ethanol, isopropanol, and butanol are preferred because they are organic solvents that do not dissolve the polymer.

[0110] Examples of surfactants include cationic surfactants, anionic surfactants, and nonionic surfactants. Examples of cationic surfactants include dodecylammonium chloride, dodecylammonium bromide, dodecyltrimethylammonium bromide, dodecylpyridinium chloride, dodecylpyridinium bromide, and hexadecyltrimethylammonium bromide. Examples of anionic surfactants include fatty acid soaps such as sodium stearate and sodium dodecanoate, sodium dodecylbenzenesulfonate, and sodium dodecyl sulfate. Examples of nonionic surfactants include polyoxyethylene dodecyl ether, polyoxyethylene hexadecyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl ether, polyoxyethylene sorbitan monooleate ether, and monodecanoyl sucrose.

[0111] Such surfactants can be used alone or in combination of two or more. Among the surfactants, anionic surfactants are preferred, and sodium dodecylbenzenesulfonate and sodium dodecyl sulfate are more preferred. The amount of surfactant added is preferably in the range of 0.01 to 10 parts by mass, more preferably in the range of 0.04 to 2 parts by mass, per 100 parts by mass of the aqueous medium.

[0112] (2) The steps from the assembly step to (6) the addition of external additives can be carried out according to various conventionally known methods. (2) The flocculant used in the association step is not particularly limited, but one selected from metal salts is preferably used.

[0113] Examples of metal salts include monovalent metal salts such as alkali metal salts like sodium, potassium, and lithium; divalent metal salts such as calcium, magnesium, manganese, and copper; and trivalent metal salts such as iron and aluminum. Specific examples of metal salts include sodium chloride, potassium chloride, lithium chloride, calcium chloride, magnesium chloride, zinc chloride, copper sulfate, magnesium sulfate, manganese sulfate, and polyaluminum chloride. Among these, divalent or trivalent metal salts are particularly preferred because they can promote aggregation in smaller quantities. These can be used individually or in combination of two or more.

[0114] [Developer] The toner of the present invention can be suitably used as the following types of toners. For example, it can be used as a one-component magnetic toner by incorporating a magnetic material, as a two-component developer by mixing it with a so-called carrier, or as a non-magnetic toner used alone. The toner of the present invention can be suitably used in all of the above cases.

[0115] Examples of magnetic materials that can be used include magnetite, γ-hematite, or various types of ferrite. As carriers for the two-component developer, magnetic particles made from conventionally known materials such as metals like iron, steel, nickel, cobalt, ferrite, and magnetite, or alloys of these metals with metals like aluminum and lead, can be used. As carriers, it is preferable to use coated carriers in which the surface of magnetic particles is coated with a coating agent such as resin, or so-called resin-dispersed carriers in which magnetic powder is dispersed in a binder resin.

[0116] There are no particular limitations on the resin used for coating, but examples include olefin resin, styrene resin, styrene-acrylic resin, silicone resin, polyester resin, or fluororesin. Furthermore, the resin used to constitute the resin-dispersed carrier is not particularly limited and any known resin can be used. Examples of such resins include acrylic resins, styrene-acrylic resins, polyester resins, fluororesins, and phenolic resins.

[0117] The median diameter of the carrier, based on volume, is preferably in the range of 20 to 100 μm, and more preferably in the range of 25 to 60 μm. The median diameter based on the volume of the carrier can typically be measured using a laser diffraction particle size distribution analyzer equipped with a wet disperser. An example of such a laser diffraction particle size distribution analyzer is the "HELOS" (manufactured by SYMPATEC). The amount of toner mixed with the carrier is preferably in the range of 2 to 10% by mass, with the total mass of toner and carrier being 100% by mass.

[0118] [Image forming method] The toner of the present invention can be suitably used in image forming methods that include a fixing step using a thermal pressure fixing method, in which pressure is applied and heating is performed. In particular, it can be suitably used in image forming methods in which fixing occurs at a relatively low temperature during the fixing step. The fixing temperature is a temperature in the range of 115 to 140°C, preferably 115 to 130°C, at the surface temperature of the heating element in the fixing nip portion.

[0119] Furthermore, it can be suitably used in high-speed fixing image formation methods where the fixing line speed is in the range of 200 to 600 mm / sec. In this image forming method, specifically, the toner of the present invention is used to develop, for example, an electrostatic image formed on a photoreceptor to obtain a toner image, and this toner image is transferred to an image support. Subsequently, the toner image transferred to the image support is fixed to the image support by a thermal pressure fixing process, thereby obtaining a printed product with a visible image formed on it.

[0120] Furthermore, the toner of the present invention can be used in monochrome image forming methods and full-color image forming methods. In a full-color image forming method, the toner can be applied to a four-cycle image forming method consisting of four color developing devices, one for yellow, magenta, cyan, and black, and one photoreceptor. It can also be applied to a tandem image forming method in which image forming units having color developing devices and photoreceptors for each color are mounted separately for each color. The toner of the present invention can be applied to any of the above image forming methods. [Examples]

[0121] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these. In the following examples, unless otherwise specified, the operations were carried out at room temperature (25°C). Unless otherwise specified, "%" and "parts" mean "mass%" and "parts by mass," respectively.

[0122] The peak molecular weight of the polymer contained in the binder resin of each toner listed below was measured as follows. The measurement results are shown in the table below. The apparatus "HLC-8220" (manufactured by Tosoh Corporation) and the column "TSKguardcolumn+TSKgelSuperHZM-M3" (manufactured by Tosoh Corporation) were used. While maintaining the column temperature at 40°C, tetrahydrofuran (THF) was flowed as the carrier solvent at a flow rate of 0.2 ml / min. Next, the sample to be measured was dissolved in tetrahydrofuran to a concentration of 1 mg / ml under dissolution conditions that involved processing with an ultrasonic disperser for 5 minutes at room temperature (25°C). Next, the sample solution was obtained by processing it through a membrane filter with a pore size of 0.2 μm, and 10 μL of this sample solution was injected into the apparatus together with the carrier solvent mentioned above. The molecular weight distribution of the sample was then determined by detection using a refractive index detector (RI detector).

[0123] [Manufacturing of Toner 1] <Preparation of Binding Resin Particle Dispersion 1> A surfactant solution, prepared by dissolving 8g of sodium dodecyl sulfate in 3L of deionized water, was placed in a 5L stainless steel kettle (SUS kettle) equipped with a stirrer, temperature sensor, cooling pipe, and nitrogen introduction device. The solution was then heated to 80°C while being stirred at a rate of 230 rpm under a nitrogen atmosphere. To this surfactant solution, an initiator solution prepared by dissolving 10 g of potassium persulfate in 200 g of deionized water was added, and the temperature was set to 80°C. Then, the monomer mixture described below was added dropwise over 100 minutes, and polymerization was carried out by heating and stirring this system at 80°C for 2 hours. In this way, binder resin particle dispersion (toner binder particle dispersion) 1 was prepared.

[0124] -Monomer mixture- Exemplary compound M1 161g Styrene (St) 467g n-butyl acrylate (BA) 161g Acrylic acid (AA) 16g n-octyl-3-mercaptopropionate 5.5g The volume-based median diameter of the binder resin particles in the obtained binder resin particle dispersion 1 was measured by dynamic light scattering using "Microtrac UPA-150" (manufactured by Nikkiso Co., Ltd.) and was found to be 128 nm.

[0125] <Preparation of colorant dispersion 1> Coloring agent: Carbon black (Mogul®L, manufactured by Cabot Corporation) 10 parts by mass Anionic surfactant (20% aqueous solution of sodium dodecylbenzenesulfonate) 1.5 parts by mass 90 parts by mass of deionized water The above components were mixed and dispersed in an SC mill to obtain colorant dispersion 1. The volume-based median diameter of the colorant particles in the dispersion was measured by dynamic light scattering using a "Microtrac UPA-150" (manufactured by Nikkiso Co., Ltd.) and was found to be 154 nm.

[0126] <Preparation of mold release agent dispersion 1> Behenyl behenate 100 parts by mass 5 parts by mass of sodium dodecyl sulfate Ion-exchanged water 240 parts by mass The above components were dispersed in a round stainless steel flask using a homogenizer "Ultra-Turrax® T50" (manufactured by IKA Corporation) for 10 minutes. Subsequently, the mixture was dispersed using a pressure-discharge homogenizer to obtain release agent dispersion 1. The volume-based median diameter of the release agent particles in the dispersion was measured using a laser diffraction particle size distribution analyzer LA-750 (manufactured by Horiba, Ltd.) and was found to be 530 nm.

[0127] <Preparation of Toner Base Particle Dispersion 1> 1,237 parts by mass of binder resin particle dispersion Colorant dispersion 1 42 parts by mass Release agent dispersion 1 18 parts by mass 1.8 parts by mass of polyaluminum chloride 600 parts by mass of deionized water The above components were mixed and dispersed in a round stainless steel flask using a homogenizer "Ultra-Turrax® T50" (manufactured by IKA). The mixture was then heated to 55°C in a heating oil bath while stirring the contents of the flask. After holding at 55°C for 30 minutes, it was confirmed that aggregated particles with a median diameter (D50) of 4.8 μm by volume had formed in the solution. Furthermore, when the temperature of the heating oil bath was increased to 56°C and maintained for 2 hours, the median diameter (D50) on a volume basis became 5.9 μm. Subsequently, 1 mol / L sodium hydroxide was added to the system to adjust the pH to 5.0. The stainless steel flask was then sealed using a magnetic seal and heated to 98°C while continuing to stir. Stirring was continued for 6 hours to complete the fusion (fusion) between the binder resin particles, and toner matrix particle dispersion 1 was prepared. The volume-based median diameter (D50) of the toner matrix particles in the dispersion was 6.0 μm.

[0128] <Washing and drying process> The toner matrix particle dispersion 1 was subjected to solid-liquid separation using a basket-type centrifuge "MARKIII Model No. 60×40" (manufactured by Matsumoto Machinery Sales Co., Ltd.) to form a wet cake of toner matrix particles. The wet cake was washed in the basket-type centrifuge described above with deionized water at 45°C until the electrical conductivity of the filtrate was 5 μS / cm. Then it was transferred to a "Flash Jet Dryer" (manufactured by Seishin Corporation) and dried until the moisture content was 0.5% by mass to obtain toner matrix particles.

[0129] <External additive treatment of toner base particles> To 100 parts by mass of the toner matrix particles obtained above, 1 part by mass of hydrophobic silica (number mean primary particle size = 12 nm) and 0.3 parts by mass of hydrophobic titania (number mean primary particle size = 20 nm) were added. The mixture was then mixed using a Henschel mixer (registered trademark) and subjected to external additive treatment to produce toner 1.

[0130] [Manufacturing of toner cartridges 2-23] Each binder resin particle dispersion was prepared in the same manner as described above, except that the combination and amount of the first and second polymerizable monomers were changed as shown in Tables I and II below. Furthermore, R1 to R3 of the first polymerizable monomer listed in Tables I and II below represent R1 to R3 in the general formula (2) above. Furthermore, the first polymerizable monomer used in the preparation of the binder resin particle dispersion 14 is comparative compound 1, described below. The first polymerizable monomer used in the preparation of the binder resin particle dispersion 15 is comparative compound 2, described below.

[0131] [ka]

[0132] Furthermore, each release agent dispersion was prepared in the same manner as described in Table III below, except that the type and amount of release agent were changed as described in Table III below. Next, toners 2 to 23 were manufactured in the same manner as toner 1, except that each toner matrix particle was prepared using a binder resin particle dispersion, a colorant dispersion, a mold release agent dispersion, polyaluminum chloride, and ion-exchanged water to have the content and composition described in Tables IV to VI below.

[0133] Furthermore, the volume-based median diameter of the binder resin particles in the binder resin particle dispersions prepared using the monomer combinations and addition amounts shown in Tables I and II below was 128 nm in all cases. Furthermore, the volume-based median diameter of the release agent particles in each release agent dispersion prepared using the release agents listed in Table III below was as follows: Paraffin (paraffin wax, HNP-51, manufactured by Nippon Seiro Co., Ltd.): 600nm Pentaerythritol tetrabehenate: 490nm • Ethylene glycol distearate: 380nm • Stearyl stearate: 460nm Methyl lignocerate: 430nm Hexadecyl palmitate: 450nm Methyl triacontanoate: 450nm

[0134] In Tables I and II below, St represents styrene, MMA represents methyl methacrylate, nBA represents n-butyl acrylate, iBA represents iso-butyl acrylate, 2EHA represents 2-ethylhexyl acrylate, MAA represents methacrylic acid, and AA represents acrylic acid. Note that the amounts of the first polymerizable monomer and the second polymerizable monomer added in Tables I and II represent the amounts added when the total amount of the first and second monomers added is set to 100% by mass. Also, the amount of release agent added in Table III represents the amount of release agent added in the release agent dispersion. In the table below, "H" represents a hydrogen atom, "Me" represents a methyl group, "n-Pro" represents an n-propyl group, "iso-Pro" represents an iso-propyl group, "OMe" represents a methoxy group, "On-Pro" represents an n-propoxy group, and "n-Bu" represents an n-butyl group.

[0135] [Preparation of two-component developer] 100 parts by mass of ferrite particles (volume-based median diameter: 50 μm (manufactured by Powdertech Co., Ltd.)) and 4 parts by mass of methyl methacrylate-cyclohexyl methacrylate copolymer resin (volume-based median diameter of primary particles: 85 nm) were placed in a horizontal-blade high-speed stirring device and mixed for 15 minutes at a blade peripheral speed of 8 m / s and a temperature of 30°C. The temperature was then raised to 120°C and stirring was continued for 4 hours. After cooling, fragments of the methyl methacrylate-cyclohexyl methacrylate copolymer resin were removed using a 200-mesh sieve to prepare a resin-coated carrier. This resin-coated carrier was mixed with each of the above toners 1 to 23 so that the toner concentration was 7% by mass relative to the total mass of the toner and carrier, thereby preparing two-component developers 1 to 23.

[0136] [Table 1]

[0137] [Table 2]

[0138] [Table 3]

[0139] [Table 4]

[0140] [Table 5]

[0141] [Table 6]

[0142] [evaluation] The following evaluation items (1), (2), and (3) were evaluated using two-component developers 1 to 23, and the evaluation results are shown in Table VII below.

[0143] (1) Fixation A commercially available multifunction printer, the "bizhub PRO C6500" (manufactured by Konica Minolta Business Technologies), was used as the image forming apparatus. The two-component developer described above was loaded into this apparatus. The surface temperature of the fixing heating element in the hot roll fixing method was changed in 5°C increments within the range of 80 to 150°C. For each temperature, under normal temperature and humidity conditions (temperature 20°C, humidity 50%RH), the image support weighed 350 g / m². 2 Image formation was performed using thick cardboard, and a solid image with an image density of 0.8 was obtained as a visible image. Subsequently, the fixed solid image was folded using a folding machine, and air at 0.35 MPa was blown onto it. The state of the folds was evaluated on a 5-point scale referring to a limit sample, and the fixing temperature of rank 3 was set as the minimum fixing temperature. Rank 5: No peeling at all along the folds. Rank 4: Some peeling along the folds. Rank 3: Thin linear peeling along the folds. Rank 2: Thick peeling along the folds. Rank 1: Significant peeling in the image. If the minimum fixing temperature indicating rank 3 is 130°C or lower, it will exhibit sufficient low-temperature fixing properties.

[0144] (2) Electrostatic properties The charge level of the toner was measured using the apparatus shown in Figure 1. First, 1 g of developer, weighed using a precision balance, was evenly distributed across the entire surface of the conductive sleeve (31). A voltage of 2 kV was supplied to the sleeve (31) from the bias power supply (33), and the rotation speed of the magnetic roll (32) installed inside the conductive sleeve (31) was set to 1000 rpm. This state was left for 30 seconds to collect the toner on the cylindrical electrode (34). After 30 seconds, the potential Vm of the cylindrical electrode (34) was read, and the amount of charge of the toner was determined. Furthermore, the mass of the collected toner was measured using a precision balance to determine the average charge. The value obtained by dividing the average charge by the mixing time (mixing for 10 minutes using a shaker (Yayoi New-YS) with a swing angle of 30° and a shaking rate of 200 strokes / min) was used as the charge index. If the charge index is 6.5 μC / g / min or higher, it will show a sufficient amount of charge that does not cause problems even during high-speed print output.

[0145] (3) Fixation and separation properties A modified "bizhub(registered trademark) C754" (manufactured by Konica Minolta, Inc.) was used. The recording material "Kinto 85g / m²" was left overnight in a normal temperature and humidity environment (temperature 25°C, relative humidity 50%RH) to adjust its humidity. 2 We used "T-grain" (manufactured by Oji Paper Co., Ltd.). On the recording material, under normal temperature and humidity conditions (temperature 25°C, humidity 50%RH), the following conditions were met: nip width 11.2 mm, fixing time 34 msec, fixing pressure 133 kPa, fixing temperature at which the upper belt reached 160°C, and toner adhesion amount 4.0 g / m². 2 A test was conducted to print a full-page solid image with an 8mm margin at the front edge, and this was repeated until a paper jam occurred, while gradually decreasing the margin in 1mm increments from 7mm to 6mm. The minimum leading margin that did not cause a paper jam was investigated, and this was used to evaluate the paper's ability to fix and separate. The results are shown in Table VII. A smaller minimum leading margin indicates superior paper fixation and separation. In this invention, evaluation criteria "AA" and "A" are considered acceptable. (Evaluation Criteria) AA....Tip margin is 2mm or less A. The margin at the tip is 3mm or less. B. The margin at the tip is 4mm or less. C...The margin at the tip exceeds 4mm.

[0146] [Table 7]

[0147] As is clear from the results shown in Table VII above, it has been found that by including a polymer having the structural unit represented by the general formula (1) and a release agent, toners 1 to 19 of the present invention can be obtained to have excellent low-temperature fixability and fixation separation properties, as well as good electrostatic properties. On the other hand, it was found that toners 20-21 using polymers having structures other than those of the present invention exhibited inferior fixing and separation properties, and furthermore, toners 22-23 using polymers not having the structure of the present invention exhibited even greater electrostatic properties. [Explanation of Symbols]

[0148] 31 Conductive Sleeve 32 Magnetic Rolls 33 Bias Power Supply 34 Cylindrical electrodes

Claims

1. A toner for developing electrostatic images containing toner particles, The toner particles contain a polymer having a structural unit represented by general formula (1) as a binder resin, and also contain a release agent. A toner for developing electrostatic images, characterized by the following features. 【Chemistry 1】 [In the above general formula (1), R １ R represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. ２ and R ３ Each of these independently represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group.

2. The mold release agent is a fatty acid ester using a fatty acid having 16 to 24 carbon atoms. The electrostatic image developing toner according to feature 1.

3. In the above general formula (1), R １ However, it is a hydrogen atom or a methyl group, R ２ and R ３ However, each is independently a hydrogen atom or a methoxy group. The electrostatic image developing toner according to feature 1.

4. In the above general formula (1), R ２ and R ３ However, it is a hydrogen atom. The electrostatic image developing toner according to feature 1.

5. The polymer having the structural unit represented by the general formula (1) is a copolymer of a first polymerizable monomer having the structure represented by the general formula (2) below and another polymerizable monomer copolymerizable with the first polymerizable monomer. The electrostatic image developing toner according to feature 1. 【Chemistry 2】 [In the above general formula (2), R １ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R ２ and R ３ each independently represent a hydrogen atom, an alkyl group having 1 to 3 carbon atoms or an alkoxy group.]]

6. The content of structural units derived from the first polymerizable monomer is in the range of 10 to 35% by mass relative to the total structural units (100% by mass) constituting the polymer having the structural units represented by the general formula (1). The electrostatic image developing toner according to feature 5.

7. The other polymerizable monomer is selected from the group consisting of at least styrenes, acrylic acid, methacrylic acid, acrylic acid esters, and methacrylic acid esters. The electrostatic image developing toner according to feature 5.

8. The other polymerizable monomer is selected from one or more of styrene, acrylic acid, n-butyl acrylate, iso-butyl acrylate, 2-ethylhexyl acrylate, and methacrylic acid. The electrostatic image developing toner according to feature 7.

9. The fatty acid ester using a fatty acid having 16 to 24 carbon atoms is behenyl behenate. The electrostatic image developing toner according to feature 2.

10. The fatty acid ester using a fatty acid having 16 to 24 carbon atoms is pentaerythritol tetrabehenate. The electrostatic image developing toner according to feature 2.

11. The fatty acid ester using a fatty acid having 16 to 24 carbon atoms is ethylene glycol distearate ester. The electrostatic image developing toner according to feature 2.

12. The content of the fatty acid ester, which uses a fatty acid having 16 to 24 carbon atoms, in the toner for developing electrostatic images is in the range of 5 to 20% by mass. The electrostatic image developing toner according to feature 2.

13. A method for manufacturing an electrostatic image developing toner according to any one of claims 1 to 12, The process includes a step of polymerizing a first polymerizable monomer having a structure represented by the following general formula (2) to prepare a toner binder particle dispersion containing the mold release agent. A method for manufacturing toner for electrostatic image developing, characterized by the features described above. 【Transformation 3】 [In the above general formula (2), R １ R represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. ２ and R ３ Each of these independently represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group.

14. A method for manufacturing a toner for electrostatic image development according to any one of claims 2 to 12, The process involves polymerizing a first polymerizable monomer having a structure represented by the following general formula (2), and preparing a toner binder particle dispersion containing a fatty acid ester using a fatty acid having 16 to 24 carbon atoms as a release agent. A method for manufacturing toner for electrostatic image developing, characterized by the features described above. 【Chemistry 4】 [In the above general formula (2), R １ R represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. ２ and R ３ Each of these independently represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group.

15. The fatty acid ester using a fatty acid having 16 to 24 carbon atoms is behenyl behenate. A method for manufacturing toner for electrostatic image developing according to claim 14.

16. The fatty acid ester using the aforementioned fatty acid having 16 to 24 carbon atoms is pentaerythr It is litol tetrabehenate. A method for manufacturing toner for electrostatic image developing according to claim 14.

17. The fatty acid ester using a fatty acid having 16 to 24 carbon atoms is ethylene glycol distearate ester. A method for manufacturing toner for electrostatic image developing according to claim 14.

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