Toner for electrostatic charge image development and method for producing the same

Abstract

To provide a toner for electrostatic charge image development that can prevent electrostatic sticking of printed materials while satisfying heat-resistant storage properties and low temperature fixability, and a method for manufacturing the same.SOLUTION: A toner for electrostatic charge image development of the present invention is a toner for electrostatic charge image development including a toner base particle containing a binder resin and a colorant. The toner base particle contains, as the binder resin, at least a polymer having a first structural unit represented by the following general formula (1) and a polymer having a specific second structural unit having a norbornene ester skeleton, or a copolymer having the first structural unit and the second structural unit. In general formula (1), R1 represents a hydrogen atom or an alkoxy group having 1-3 carbon atoms.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a toner for electrostatic charge image development and a method for manufacturing the same. More specifically, the present invention relates to a toner for electrostatic charge image development that can suppress electrostatic adhesion of printed matter while satisfying heat storage stability and low-temperature fixability.

Background Art

[0002] In the printing field that performs image formation by an electrophotographic method, in recent years, there has been a demand for a toner for electrostatic charge image development (hereinafter, also simply referred to as "toner") that can cope with reduction of power consumption, speeding up of printing, diversification of image forming media, improvement of image quality, reduction of environmental load, and the like.

[0003] The characteristics required for such a toner include so-called low-temperature fixability, which enables fixing of a toner image at a lower temperature than in the past, and improvement of fixing strength. Further, not limited to the conventional office market, with the expansion into the light printing market, post-treatments for adding high value to products, such as varnishing and laminating on the surface of printed matter, are often performed, and compatibility in the post-treatment process of printed matter is required.

[0004] Toner usually contains a binder resin having a binder function (hereinafter, also referred to as "toner binder"), and as this binder resin, it is known to use hybrid resins such as styrene-acrylic resins, polyester resins, and polyester resins having grafted acrylic polymer segments. Techniques for improving low-temperature fixability and the like by improving these binder resins and the like are known in response to the above requirements (see, for example, Patent Documents 1 to 3).

[0005] Also, not limited to the light printing market, reduction of the toner particle size is required to achieve high image quality of printed matter, and the toner manufacturing method has been shifting from the conventional pulverization method to the chemical method. By reducing the toner particle size, the toner can adhere more uniformly to the electrostatic latent image, and high image quality can be achieved.

[0006] In this way, by adopting a binder resin that can be fixed at a lower temperature and reducing the toner particle size, it is possible to reduce power consumption, increase printing speed, improve print quality, and reduce the environmental impact.

[0007] On the other hand, printed matter is output while contacting many transport rollers in the transport path during printing. Due to contact with these transport rollers and the like, the printed matter becomes charged, and as a result, there has been a problem that the printed matter output adheres electrostatically to each other. In particular, the higher the printing speed, the shorter the time until the charged electric charge leaks, and the stronger the electrostatic adhesion becomes. When performing post-processing such as varnish processing or laminating processing, problems such as double feeding of the printed matter become apparent, and paper handling may become difficult. In addition, when using a medium with higher insulation such as a polypropylene film or stone paper, electrostatic adhesion may become more prominent.

[0008] To address this problem, heretofore, the entire printing environment has been humidified or a humidifying unit has been provided in the printing machine itself to leak the charged electric charge and suppress electrostatic adhesion. However, continuously maintaining the printing environment at an appropriate humidity incurs cost increases, and simply providing a humidifying unit in the printing machine itself does not provide sufficient suppression of electrostatic adhesion.

[0009] In addition, a method of using a resin with easy charge leakage as a binder resin can also be considered to suppress electrostatic adhesion. However, conventional resins with easy charge leakage have a problem that the interaction between the binder resins is large and the heat-resistant storage property deteriorates, and it has been difficult to suppress the electrostatic adhesion of printed matter while satisfying the heat-resistant storage property.

Prior Art Documents

Patent Documents

[0010]

Patent Document 1

[0011] The present invention has been made in view of the above problems and situations, and the problem to be solved is to provide an electrostatic charge image developing toner and a method for manufacturing the same that can suppress electrostatic sticking of printed matter while satisfying heat-resistant storage properties and low-temperature fixing properties. [Means for Solving the Problems]

[0012] As a result of studying the causes of the above problems in order to solve the above problems, the present inventor has found that by containing a polymer having a specific structural unit as a binder resin, it is possible to provide an electrostatic charge image developing toner or the like that can suppress electrostatic sticking of printed matter while satisfying heat-resistant storage properties and low-temperature fixing properties, and has reached the present invention. That is, the above problems according to the present invention are solved by the following means.

[0013] 1. An electrostatic charge image developing toner containing toner base particles containing a binder resin and a colorant, wherein the toner base particles contain, as the binder resin, at least a polymer having a first structural unit represented by the following general formula (1) and a polymer having a second structural unit represented by the following general formula (2), or a copolymer having the first structural unit and the second structural unit and the composition ratio X represented by the following formula (I) is in the range of 25 to 75% by mass An electrostatic charge image developing toner characterized by the above. Formula (I): X [% by mass] = W 1 / (W 1 +W 2 )×100 W1 : the mass of the first structural unit in the total binder resin W 2 : the mass of the second structural unit in the total binder resin [Chemical formula] [In general formula (1), R 1 represents a hydrogen atom or an alkoxy group having 1 to 3 carbon atoms.] [Chemical formula] [In general formula (2), R 2 represents a hydrogen atom child .]

[0014] 2. The toner base particles contain, as the binder resin, a copolymer having the first structural unit and the second structural unit . The electrostatic charge image developing toner according to claim 1, characterized in that

[0015] 3. R in the general formula (1) 1 represents a hydrogen atom or a methoxy group . The electrostatic charge image developing toner according to claim 1 or 2, characterized in that

[0017] 4 . R in the general formula (1) 1 represents a methoxy group . The electrostatic charge image developing toner according to any one of claims 1 to 3 n.

[0019] 5 . The copolymer further has a third structural unit different from the first structural unit and the second structural unit . The electrostatic charge image developing toner according to any one of claims 1 to 4 n.

[0021] 6 . The third structural unit is at least a structural unit derived from an acrylate or a methacrylate . The electrostatic charge image developing toner according to claim5 The toner for electrostatic charge image development according to the item.

[0022] 7 . The third structural unit is at least a structural unit derived from acrylic acid, n-butyl acrylate, 2-ethylhexyl acrylate, or methacrylic acid Characterized by the first 5 The toner for electrostatic charge image development according to the item.

[0023] 8 . A method for manufacturing a toner for electrostatic charge image development containing toner base particles containing a binder resin and a colorant, having a step of copolymerizing at least a first monomer having a structure represented by the following general formula (3) and a second monomer having a structure represented by the following general formula (4) to prepare a particle dispersion of the binder resin and the composition ratio X represented by the following formula (I) is in the range of 25 to 75% by mass A method for manufacturing a toner for electrostatic charge image development, characterized by the above. Formula (I): X [% by mass] = W 1 / (W 1 +W 2 )×100 W 1 : the mass of the first monomer W 2 : the mass of the second monomer [Chemical formula] [In general formula (3), R 1 represents a hydrogen atom or an alkoxy group having 1 to 3 carbon atoms.] [Chemical formula] [In general formula (4), R 2 represents a hydrogen atom child .] [Advantages of the Invention]

[0024] By the above means of the present invention, it is possible to provide an electrostatic charge image developing toner that can suppress the electrostatic sticking of printed matter while satisfying heat storage stability and low-temperature fixability, and a method for manufacturing the same.

[0025] Although the mechanism of manifestation or the mechanism of action of the effects of the present invention has not been clearly understood, the following speculation is made.

[0026] The characteristics required for the toner cover a wide range, such as optical characteristics, thermal characteristics (viscoelasticity), electrical characteristics (chargeability), and heat storage stability. The toner is composed of various constituent materials. Among them, for the binder resin, which is one of the constituent materials of the toner, control of viscoelasticity, heat storage stability, and chargeability is required. Specifically, through the control of the resin type, monomer composition, and manufacturing conditions, optimization of the average molecular weight, softening point, glass transition point (Tg), etc. is carried out according to the required characteristics.

[0027] A typical resin composition used for the binder resin is styrene-acrylic resin. For the control of viscoelasticity and heat storage stability, styrene is often used as the hard segment with a high Tg, and n-butyl acrylate is used as the soft segment with a low Tg as the main components. Consideration has been given to the molecular weight and the ratio of the hard segment / soft segment, and adjustments have been made.

[0028] Here, in order to achieve low-temperature fixing, although it is effective to lower the styrene ratio with a high Tg and lower the Tg of the binder resin, there is a trade-off relationship in which the heat storage stability deteriorates. For example, there is a design limit such that the Tg needs to be 45°C or higher.

[0029] Regarding the control of chargeability, the saturation charge amount is said to be proportional to the reciprocal of the dielectric loss tangent tanδ (dielectric loss (ε'') / dielectric constant (ε')). tanδ depends on the resin composition, and the chargeability can be controlled by adjusting the composition ratio. It is known that the tanδ of styrene-based resins is low and that of (meth)acrylate-based resins is high. Also, to promote the leakage of charged charges, a higher tanδ is better, and to suppress electrostatic sticking, it is effective to lower the styrene ratio with a low tanδ.

[0030] However, lowering the styrene ratio deteriorates the heat-resistant storage property described above, so it is practically difficult to control. To solve the above problem, by introducing a structure represented by the general formula (1) with a high Tg and a structure represented by the general formula (2) with a high Tg and a high tanδ as the binder resin composition, it becomes possible to increase tanδ while maintaining the glass transition temperature. As a result, it is possible to provide an electrostatic charge image developing toner that suppresses electrostatic sticking of printed matter while satisfying low-temperature fixability and is excellent in productivity including post-processing steps without deteriorating the heat-resistant storage property.

[0031] The reason why the toner of the present invention can suppress the electrostatic sticking of printed matter while satisfying low-temperature fixability is that by introducing a structure represented by the general formula (2) having a bulky substituent, it becomes possible to keep the intermolecular force between polymer chains low. Therefore, it can be inferred that it is possible to maintain the heat-resistant storage property and low-temperature fixability while suppressing the electrostatic sticking property due to a high tanδ.

[0032] Due to these expression mechanisms or action mechanisms, it is possible to provide an electrostatic charge image developing toner and a method for manufacturing the same that can suppress the electrostatic sticking of printed matter while satisfying the heat-resistant storage property and low-temperature fixability.

Embodiments for Carrying Out the Invention

[0033] The toner for electrostatic charge image development of the present invention is a toner for electrostatic charge image development containing toner base particles containing a binder resin and a colorant, wherein the toner base particles contain, as the binder resin, at least a polymer having a first structural unit represented by the above general formula (1) and a polymer having a second structural unit represented by the above general formula (2), or a copolymer having the first structural unit and the second structural unit. This feature is a technical feature common to or corresponding to each of the following embodiments.

[0034] As an embodiment of the toner for electrostatic charge image development of the present invention, from the viewpoint of enabling uniform charge leakage in order to suppress electrostatic adhesion, it is preferable that the toner base particles contain, as the binder resin, a copolymer having the first structural unit and the second structural unit.

[0035] As an embodiment of the toner for electrostatic charge image development of the present invention, from the viewpoint of low-temperature fixability, R in the above general formula (1) 1 preferably represents a hydrogen atom or a methoxy group, and more preferably represents a methoxy group.

[0036] As an embodiment of the toner for electrostatic charge image development of the present invention, from the viewpoint of suppressing electrostatic adhesion, R in the above general formula (2) 2 preferably represents a hydrogen atom or a methyl group, and more preferably represents a hydrogen atom.

[0037] As an embodiment of the toner for electrostatic charge image development of the present invention, from the viewpoint of adjusting thermal properties, it is preferable that the copolymer further has a third structural unit different from the first structural unit and the second structural unit.

[0038] As an embodiment of the toner for electrostatic charge image development of the present invention, from the viewpoint of the balance between low-temperature fixability and suppression of electrostatic adhesion, it is preferable that the composition ratio X represented by the following formula (I) is in the range of 25 to 75% by mass. Formula (I): X [% by mass] = W 1 / (W 1 + W 2 ) × 100 W 1 : Mass of the first structural unit in the total binder resin W 2 : Mass of the second structural unit in the total binder resin

[0039] As an embodiment of the toner for electrostatic charge image development of the present invention, from the viewpoint of heat-resistant storage stability, it is preferable that the third structural unit is at least a structural unit derived from an acrylate ester or a methacrylate ester.

[0040] As an embodiment of the toner for electrostatic charge image development of the present invention, from the viewpoint of heat-resistant storage stability, it is preferable that the third structural unit is at least a structural unit derived from acrylic acid, n-butyl acrylate, 2-ethylhexyl acrylate, or methacrylic acid.

[0041] The method for producing a toner for electrostatic charge image development of the present invention is a method for producing a toner for electrostatic charge image development including toner base particles containing a binder resin and a colorant, and includes a step of copolymerizing at least a first monomer having a structure represented by the general formula (3) above and a second monomer having a structure represented by the general formula (4) above to prepare a particle dispersion of the binder resin.

[0042] Hereinafter, the present invention, its components, and forms and aspects for implementing the present invention will be described. In the present application, "~" is used in the sense of including the numerical values described before and after it as a lower limit value and an upper limit value.

[0043] [Toner for Electrostatic Charge Image Development of the Present Invention] The toner for electrostatic charge image development of the present invention is a toner for electrostatic charge image development including toner base particles containing a binder resin and a colorant, wherein the toner base particles contain, as the binder resin, at least a polymer having a first structural unit represented by the general formula (1) above and a polymer having a second structural unit represented by the general formula (2) above, or a copolymer having the first structural unit and the second structural unit.

[0044] In this specification, the "toner base particle" constitutes the base of the "toner particle". The "toner base particle" contains at least a binder resin and a colorant, and may contain other components such as a release agent and a charge control agent as necessary. The "toner base particle" is referred to as a "toner particle" by adding an external additive. And the "toner" refers to an aggregate of "toner particles".

[0045] <Binder resin> The electrostatic charge image developing toner of the present invention is characterized by satisfying at least one of the following requirement A or requirement B. Also, from the viewpoint of enabling uniform charge leakage in order to suppress electrostatic adhesion, it is particularly preferable to satisfy requirement B.

[0046] Requirement A: The toner base particle contains, as a binder resin, "a polymer having a first structural unit represented by the following general formula (1)" and "a polymer having a second structural unit represented by the following general formula (2)". Requirement B: The toner base particle contains, as a binder resin, "a copolymer having a first structural unit represented by the following general formula (1) and a second structural unit represented by the following general formula (2)".

[0047] Hereinafter, the "polymer having a first structural unit represented by the following general formula (1)" is simply referred to as the "polymer having a first structural unit", the "polymer having a second structural unit represented by the following general formula (2)" is simply referred to as the "polymer having a second structural unit", and the "copolymer having a first structural unit represented by the following general formula (1) and a second structural unit represented by the following general formula (2)" is also simply referred to as the "copolymer having a first structural unit and a second structural unit".

[0048] The "copolymer having a first structural unit and a second structural unit" corresponds to both the "polymer having a first structural unit" and the "polymer having a second structural unit". Therefore, requirement B is a limiting requirement of requirement A.

[0049] In the following description, the "polymer having a first structural unit" and the "polymer having a second structural unit" are collectively referred to as the "polymer according to the present invention". The "polymer according to the present invention" also includes a "copolymer having a first structural unit and a second structural unit".

[0050] (First structural unit) The first structural unit is a structural unit represented by the following general formula (1).

[0051] [Chemical formula]

[0052] In general formula (1), R 1 represents a hydrogen atom or an alkoxy group having 1 to 3 carbon atoms. Specific examples of the alkoxy group having 1 to 3 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, a t-butoxy group, and the like. R 1 is preferably a hydrogen atom or a methoxy group, particularly preferably a methoxy group, from the viewpoint of low-temperature fixability.

[0053] (Second structural unit) The second structural unit is a structural unit represented by the following general formula (2).

[0054] [Chemical formula]

[0055] In general formula (2), R 2 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. Specific examples of the alkyl group having 1 to 3 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, a t-butyl group, and the like. R 2 is preferably a hydrogen atom or a methyl group, particularly preferably a hydrogen atom, from the viewpoint of suppressing electrostatic adhesion.

[0056] The "polymer having a first structural unit" can be synthesized by polymerizing a first monomer having a structure represented by the following general formula (3) using the monomer as a polymerization material. R in general formula (3) 1 is synonymous with R in the general formula (1). 1

[0057]

Chemical formula

[0058] Specific examples of the first monomer include the following exemplified compounds M1 to M5. However, it is not limited thereto.

[0059]

Chemical formula

[0060] The "polymer having a first structural unit" may use two or more of the first monomers as a polymerization material, or may use a combination of other monomers as a polymerization material.

[0061] The "polymer having a second structural unit" can be synthesized by polymerizing a second monomer having a structure represented by the following general formula (4) using the monomer as a polymerization material. R in general formula (4) 2 is synonymous with R in the general formula (2). 2

[0062]

Chemical formula

[0063] Specific examples of the second monomer include the following exemplified compounds M6 to M10. However, it is not limited thereto.

[0064]

Chemical formula

[0065] ​​The "polymer having a second structural unit" may be a polymerization material by combining two or more second monomers, or may be a polymerization material by combining other monomers.

[0066] The "copolymer having a first structural unit and a second structural unit" can be synthesized by using at least one or more of the above-mentioned first monomer and the above-mentioned second monomer in combination as a polymerization material.

[0067] (Third structural unit) In the present invention, the "third structural unit" refers to a structural unit different from the first structural unit and the second structural unit among the structural units possessed by the "polymer according to the present invention".

[0068] From the viewpoint of adjusting the thermal properties, it is preferable that the "polymer according to the present invention" is a copolymer further having a third structural unit by further combining a monomer different from the first monomer and the second monomer (hereinafter also referred to as "third monomer") as a polymerization material.

[0069] Specific examples of the third monomer include styrene monomers such as α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o-ethylstyrene, m-ethylstyrene, p-ethylstyrene, o-acetoxystyrene, m-acetoxystyrene, 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, phenyl acrylate; methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate; and the like.

[0070] Further, as the third monomer, a monomer having an ionic dissociative group may be used. The monomer having an ionic dissociative group has a group such as a carboxy group, a sulfonic acid group, or a phosphoric acid group. Specifically, acrylic acid, methacrylic acid, maleic acid, itaconic acid, fumaric acid, etc. may be mentioned.

[0071] From the viewpoint of facilitating the adjustment of the glass transition temperature of the polymer, among the above, an acrylate, a methacrylate, acrylic acid, or methacrylic acid is preferable as the third monomer. Further, as the acrylate, n-butyl acrylate or 2-ethylhexyl acrylate is particularly preferable. That is, the copolymer further having a third structural unit is preferably a copolymer further having a structural unit derived from these preferable third monomers.

[0072] The third monomer can be used alone or in combination of two or more.

[0073] (Peak molecular weight) The "polymer according to the present invention" preferably has a peak molecular weight obtained from the molecular weight distribution in terms of polystyrene measured by gel permeation chromatography (GPC) in the range of 3500 to 35000, and more preferably in the range of 10000 to 30000. If the peak molecular weight is in such a range, the polymer has an appropriate melt viscosity during fixing, and it is possible to achieve both good fixing properties and offset resistance, which is preferable.

[0074] The "peak molecular weight" is the molecular weight corresponding to the elution time at the peak top in the molecular weight distribution. When there are a plurality of peaks in the molecular weight distribution, it refers to the molecular weight corresponding to the elution time at the peak top with the largest peak area ratio.

[0075] The method for measuring the peak molecular weight of the polymer is as follows. Using the apparatus "HLC-8220" (manufactured by Tosoh Corporation) and the column "TSKguardcolumn + TSKgel SuperHZM-M3 series" (manufactured by Tosoh Corporation), while maintaining the column temperature at 40°C, flow tetrahydrofuran (THF) as the carrier solvent at a flow rate of 0.2 ml / min, and dissolve the measurement sample in tetrahydrofuran to a concentration of 1 mg / ml under the dissolution conditions of treating it for 5 minutes using an ultrasonic disperser at room temperature (25°C). Then, treat it with a membrane filter having a pore size of 0.2 μm. Inject 10 μl of the treated sample solution into the apparatus together with the above carrier solvent, and detect the molecular weight distribution of the measurement sample using a refractive index detector (RI detector). Measure the peak molecular weight from the detected molecular weight distribution.

[0076] (Composition ratio of the binder resin) When the total mass of all the binder resins contained in the toner base particles is 100% by mass, the total mass of the "polymer according to the present invention" is preferably in the range of 65 to 99% by mass, more preferably in the range of 70 to 97% by mass, and even more preferably in the range of 75 to 95% by mass from the viewpoint of the balance between fixability and offset resistance.

[0077] In the toner of the present invention, the composition ratio X represented by the following formula (I) is preferably in the range of 25 to 75% by mass, and more preferably in the range of 30 to 70% by mass. Formula (I): X [% by mass] = W 1 / (W 1 +W 2 )×100 W 1 : The mass of the first structural unit in all the binder resins W 2 : The mass of the second structural unit in all the binder resins

[0078] In the "polymer according to the present invention", the composition ratio of the third structural unit is not particularly limited and can be appropriately adjusted depending on the type of the structural unit.

[0079] For example, when the third structural unit is a structural unit derived from an acrylate or a methacrylate, it is preferably in the range of 5 to 50% by mass, more preferably in the range of 10 to 40% by mass, when the total of the "polymer according to the present invention" is 100% by mass.

[0080] Further, when the third structural unit is a structural unit derived from a monomer having an ionic dissociable group, it is preferably in the range of 3 to 8% by mass when the total of the "polymer according to the present invention" is 100% by mass.

[0081] (Other resins) The toner base particles according to the present invention may contain a resin other than the "polymer according to the present invention" (hereinafter also referred to as "other resin") as a binder resin.

[0082] Specific examples of the other resin include, for example, polyester resins, silicone resins, polyolefin resins, polyamide resins, or epoxy resins. These can be used alone or in combination of two or more.

[0083] Hereinafter, the polyester resin that can be used as a binder resin as the "other resin" will be described.

[0084] The polyester resin is a known polyester resin obtained by a polycondensation reaction of a polyvalent carboxylic acid having a valence of 2 or more (polyvalent carboxylic acid component) and an alcohol having a valence of 2 or more (polyvalent alcohol component). The polyester resin may be amorphous or crystalline.

[0085] The valences of the polyvalent carboxylic acid component and the polyvalent alcohol component are preferably 2 to 3, respectively, and particularly preferably 2, respectively. Therefore, as a particularly preferred form, the case where the valences are both 2 (that is, a dicarboxylic acid component and a diol component) will be described.

[0086] Examples of the dicarboxylic acid component include saturated aliphatic dicarboxylic acids 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 (dodecanedioic acid), 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,16-hexadecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid; unsaturated aliphatic dicarboxylic acids such as methylene succinic acid, fumaric acid, maleic acid, 3-hexenedioic acid, 3-octenedioic acid, dodecenyl succinic acid; 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, anthracenedicarboxylic acid; etc. Also, lower alkyl esters or acid anhydrides of these can be used. The dicarboxylic acid component may be used alone or in admixture of two or more.

[0087] In addition, polyvalent carboxylic acids having a valence of 3 or more such as trimellitic acid and pyromellitic acid, anhydrides of the above carboxylic acid compounds, or alkyl esters having 1 to 3 carbon atoms can also be used.

[0088] Examples of the diol component include saturated aliphatic diols such as 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, 1,20-eicosanediol, 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, 9-octadecene-7,12-diol; bisphenols such as bisphenol A and bisphenol F, and alkylene oxide adducts of these bisphenols such as ethylene oxide adducts and propylene oxide adducts, i.e., aromatic diols. Derivatives of these can also be used. The diol component may be used alone or as a mixture of two or more.

[0089] The method for producing the polyester resin is not particularly limited, and it can be produced by polycondensing (esterifying) the above polyvalent carboxylic acid component and polyhydric alcohol component using a known esterification catalyst.

[0090] Examples of the catalyst that can be used in the production of the polyester resin include alkali metal compounds such as sodium and lithium; compounds containing Group 2 elements such as magnesium and calcium; compounds of metals such as aluminum, zinc, manganese, antimony, titanium, tin, zirconium, and germanium; phosphorous acid compounds; phosphoric acid compounds; and amine compounds. Specifically, examples of the tin compound include dibutyltin oxide (dibutyltin oxide), tin octylate, tin dioctylate, and salts thereof.

[0091] Examples of the titanium compound include titanium alkoxides such as tetra-n-butyl titanate (Ti(O-n-Bu)4), tetraisopropyl titanate, tetramethyl titanate, and tetrastearyl titanate; titanium acylates such as polyhydroxy titanium stearate; and titanium chelates such as titanium tetraacetylacetonate, titanium lactate, and titanium triethanolamine.

[0092] Examples of the germanium compound include germanium dioxide.

[0093] Examples of the aluminum compound further include polyaluminum hydroxide, aluminum alkoxide, tributylaluminum, etc. These may be used alone or in combination of two or more.

[0094] The polymerization temperature is not particularly limited, but it is preferably in the range of 70 to 250°C. Also, the polymerization time is not particularly limited, but it is preferably 0.5 to 10 hours. During the polymerization, the inside of the reaction system may be depressurized as necessary.

[0095] The above polyester resin may be a hybrid polyester resin having a graft copolymer structure of a polyester polymerization segment and a graft of a styrene·acrylic polymerization segment.

[0096] <Colorant> The toner base particles according to the present invention contain a colorant. As the colorant, generally known dyes and pigments can be used.

[0097] Examples of the colorant for obtaining a black toner include carbon black, magnetic materials, iron·titanium composite oxide black, etc. Examples of carbon black include channel black, furnace black, acetylene black, thermal black, lamp black, etc.

[0098] Examples of colorants for obtaining yellow toner include dyes such as C.I. Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162; and pigments such as C.I. Pigment Yellow 14, 17, 74, 93, 94, 138, 155, 180, 185.

[0099] Examples of colorants for obtaining magenta toner include dyes such as C.I. Solvent Red 1, 49, 52, 58, 63, 111, 122; and pigments such as C.I. Pigment Red 5, 48:1, 53:1, 57:1, 122, 139, 144, 149, 166, 177, 178, 222.

[0100] Examples of colorants for obtaining cyan toner include dyes such as C.I. Solvent Blue 25, 36, 60, 70, 93, 95; and pigments such as C.I. Pigment Blue 1, 7, 15, 60, 62, 66, 76.

[0101] For each color of toner, the colorants for obtaining the toner can be used alone or in combination of two or more.

[0102] The content ratio of the colorant is preferably in the range of 0.5 to 20% by mass, more preferably in the range of 2 to 10% by mass, with the total mass of the toner base particles being 100% by mass.

[0103] <Release agent> The toner base particles according to the present invention may contain a release agent. The release agent is preferably a fatty acid ester wax.

[0104] Examples of fatty acid ester waxes 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), glycerin monostearate (glyceryl stearate), diglyceryl distearate (diglyceryl distearate), pentaerythritol 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, methyl triacontanate (methyl triacontanate), and the like. These fatty acid ester waxes can be used alone or in combination of two or more.

[0105] These fatty acid ester waxes may be commercially available products or synthetic products.

[0106] Also, the release agent may be a wax other than the fatty acid ester wax.

[0107] Examples of waxes other than fatty acid ester waxes include, for example, polyolefin waxes such as low molecular weight polyethylene and low molecular weight polypropylene, branched hydrocarbon waxes such as microcrystalline wax, paraffin wax, long chain hydrocarbon waxes such as sasol wax, dialkyl ketone waxes such as distearyl ketone, fatty acid amide waxes such as ethylenediamine behenylamide and tristearyl trimellitate amide, and the like.

[0108] The content ratio of the release agent is preferably in the range of 1 to 25% by mass, more preferably in the range of 5 to 20% by mass, based on 100% by mass of the total of the "polymer according to the present invention" from the viewpoint of the balance between fixing property and offset resistance.

[0109] <Charge control agent> The toner base particles according to the present invention may contain a charge control agent.

[0110] The charge control agent to be used is a substance capable of imparting positive or negative charge by triboelectrification, and is not particularly limited as long as it is colorless, and various known positive charge control agents and negative charge control agents can be used.

[0111] Specifically, examples of the positive charge control agent include nigrosine dyes such as "Nigrosine Base EX" (manufactured by Orient Chemical Industries, Ltd.), quaternary ammonium salts such as "Quaternary Ammonium Salt P-51" (manufactured by Orient Chemical Industries, Ltd.) and "Copy Charge PX VP435" (manufactured by Hoechst Japan, Ltd.), alkoxylated amines, alkylamides, molybdate chelate pigments, and imidazole compounds such as "PLZ1001" (manufactured by Shikoku Chemicals Corporation).

[0112] Examples of the negative charge control agent include metal complexes such as "Bontron (registered trademark) S-22", "Bontron (registered trademark) S-34", "Bontron (registered trademark) E-81", "Bontron (registered trademark) E-84" (all manufactured by Orient Chemical Industries, Ltd.) and "Spiro Black TRH" (manufactured by Hodogaya Chemical Co., Ltd.), thioindigo pigments, quaternary ammonium salts such as "Copy Charge NX VP434" (manufactured by Hoechst Japan, Ltd.), calixarene compounds such as "Bontron (registered trademark) E-89" (manufactured by Orient Chemical Industries, Ltd.), boron compounds such as "LR147" (manufactured by Nippon Carlit Co., Ltd.), and fluorine compounds such as magnesium fluoride and carbon fluoride.

[0113] As metal complexes used as negatively charged charge control agents, in addition to those shown above, various structures such as metal complexes of oxycarboxylic acids, metal complexes of dicarboxylic acids, metal complexes of amino acids, metal complexes of diketones, metal complexes of diamines, metal complexes having an azo group-containing benzene-benzene derivative skeleton, and metal complexes having an azo group-containing benzene-naphthalene derivative skeleton can be used.

[0114] By configuring the toner base particles to contain the charge control agent in this way, the chargeability of the toner is improved.

[0115] The content ratio of the charge control agent is preferably in the range of 0.01 to 30% by mass, more preferably in the range of 0.1 to 10% by mass, with the total mass of the toner base particles being 100% by mass.

[0116] (Form of toner base particles) The form of the toner base particles according to the present invention is not particularly limited, and for example, it can take forms such as a so-called single-layer structure (a homogeneous structure that is not a core-shell type), a core-shell structure, a multilayer structure of three or more layers, and a domain-matrix structure.

[0117] <External additive> In order to improve the fluidity, chargeability, cleaning property, etc. of the toner, external additives such as fluidizing agents and cleaning aids, which are so-called post-treatment agents, may be added to the toner base particles to constitute the toner of the present invention.

[0118] Examples of the external additives include inorganic particles such as 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 alone or in combination of two or more.

[0119] These inorganic particles may be surface-treated with a silane coupling agent, a titanium coupling agent, a higher fatty acid, silicone oil, etc. to improve heat-resistant storage stability and environmental stability.

[0120] The addition amount of the external additive is preferably in the range of 0.05 to 5 parts by mass, more preferably in the range of 0.1 to 3 parts by mass, based on 100 parts by mass of the total mass of the toner base particles.

[0121] <Average particle diameter of toner> The average particle diameter of the toner is preferably in the range of 4 to 10 μm, more preferably in the range of 5 to 9 μm, in terms of the volume-based median diameter (D50). When the volume-based median diameter (D50) of the toner is within the above range, the transfer efficiency is increased, the halftone image quality is improved, and the image quality of fine lines, dots, etc. is improved.

[0122] In the present invention, the volume-based median diameter (D50) of the toner is measured and calculated using a measuring device connected to a computer system (manufactured by Beckman Coulter, Inc.) equipped with "Software V3.51" for data processing and the "Coulter Counter 3" (manufactured by Beckman Coulter, Inc.).

[0123] Specifically, 0.02 g of the measurement sample (toner) is added to 20 mL of a surfactant solution (for example, a surfactant solution obtained by diluting a neutral detergent containing a surfactant component 10 times with pure water for the purpose of dispersing toner particles), allowed to mix well, and then ultrasonic dispersion is performed for 1 minute to prepare a toner dispersion. This toner dispersion is pipetted into a beaker containing "ISOTON II" (manufactured by Beckman Coulter, Inc.) in a sample stand until the display concentration of the measuring device reaches 8%.

[0124] Here, by setting the concentration range in this way, reproducible measurement values can be obtained. In the measuring device, the number of measured particles is set to 25,000, the aperture diameter is set to 50 μm, the frequency values are calculated by dividing the measurement range of 1 to 30 μm into 256 segments, and the particle diameter at 50% from the larger volume integration fraction is defined as the volume-based median diameter (D50).

[0125] [Method for manufacturing toner] The method for manufacturing the electrostatic charge image developing toner of the present invention is not particularly limited. For example, a dispersion liquid of binder resin particles is prepared by emulsion polymerization, mini-emulsion polymerization, etc. of monomers that become polymerization materials in an aqueous medium, and an emulsification aggregation method is used in which a dispersion liquid of colorant particles and, if necessary, a dispersion liquid of release agent particles are aggregated and fused. Alternatively, the binder resin, colorant, and, if necessary, a release agent, etc. according to the present invention can be melt-kneaded and then pulverized, classified, etc. to obtain toner. Also, toner can be obtained by the suspension polymerization method described in JP-A-2010-191043.

[0126] Among these, from the viewpoint that it is easy to control the particle diameter and shape and the energy cost during production can be reduced, a manufacturing method using the emulsification aggregation method is preferable. As the emulsification aggregation method, the methods described in JP-A-5-265252, JP-A-6-329947, JP-A-9-15904, etc. can be adopted.

[0127] Hereinafter, the details of the manufacturing method using the emulsification aggregation method will be described.

[0128] The manufacturing method using the emulsification aggregation method can be carried out in the following steps (1A) to (1C). (1A) Binder resin particle dispersion liquid preparation step of preparing a dispersion liquid of binder resin particles (1B) Colorant particle dispersion liquid preparation step of preparing a dispersion liquid of colorant particles (1C) Release agent particle dispersion liquid preparation step of preparing a dispersion liquid of release agent particles (2) Aggregation step: Adding a flocculant to an aqueous medium in which binder resin particles, colorant particles, and release agent particles are present, allowing salting out to proceed while performing aggregation and fusion to form aggregated particles. (3) Aging step: Forming toner particles by controlling the shape of the aggregated particles. (4) Filtration and washing step: Filtering the toner particles from the aqueous medium and removing surfactants and the like from the toner particles. (5) Drying step: Drying the washed toner particles. (6) External additive addition step: Adding an external additive to the dried toner particles.

[0129] Hereinafter, the steps (1A) to (1C) will be described.

[0130] (1A) Binder resin particle dispersion preparation step In this step, resin particles are formed by conventionally known emulsion polymerization or the like, and these resin particles are aggregated and fused to form binder resin particles. As an example, monomers that are polymerization materials for the binder resin (the first monomer, the second monomer, and, if necessary, the third monomer in the case of the "polymer according to the present invention") are introduced into and dispersed in an aqueous medium, and polymerized with a water-soluble radical polymerization initiator to prepare a binder resin particle dispersion.

[0131] Commercially available products or synthetic products may be used for each monomer.

[0132] As the water-soluble radical polymerization initiator, persulfates such as potassium persulfate and ammonium persulfate, azobisaminodipropionic acid salt, azobiscyanovaleric acid and its salts, hydrogen peroxide, etc. can be used.

[0133] In addition to the above emulsion polymerization, as a method for preparing a binder resin particle dispersion, a binder resin particle dispersion can also be obtained by a method of dispersing a binder resin obtained by radical polymerization or the like in an aqueous medium without using an organic solvent. Further, a binder resin obtained by radical polymerization or the like is dissolved in an organic solvent such as ethyl acetate to form a solution, and the solution is emulsified and dispersed in an aqueous medium using a disperser, and then a desolvation treatment is performed. A binder resin particle dispersion can also be obtained by this method.

[0134] Even when preparing a binder resin particle dispersion by a method other than emulsion polymerization, from the viewpoint of easy synthesis, radical polymerization is preferable as the method for polymerizing the binder resin.

[0135] Examples of the radical polymerization initiator used in radical polymerization include oil-soluble radical polymerization initiators in addition to the above-mentioned water-soluble radical polymerization initiators. Specific examples of the oil-soluble radical polymerization initiator include azo-based or diazo-based polymerization initiators, peroxide-based polymerization initiators, and the like.

[0136] Examples of the azo-based or diazo-based polymerization initiator include 2,2'-azobis-(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile, and the like.

[0137] Examples of the peroxide-based polymerization initiator include benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxydicarbonate, 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, tris-(t-butylperoxy)triazine, and the like.

[0138] For radical polymerization, if necessary, known chain transfer agents such as n-octyl mercaptan and n-octyl 3-mercaptopropionate may be used.

[0139] Also, for dispersion, it is preferably polymerized in the presence of a known surfactant as appropriate (for example, an anionic surfactant such as sodium polyoxyethylene (2) dodecyl ether sulfate, sodium dodecyl sulfate, and sodium dodecylbenzenesulfonate).

[0140] The polymerization temperature varies depending on the type of monomer and polymerization initiator used, but is preferably in the range of 50 to 100 °C, and more preferably in the range of 55 to 90 °C. Also, the polymerization time varies depending on the type of monomer and polymerization initiator used, but is preferably, for example, 1 to 12 hours.

[0141] In the step of preparing the binder resin particle dispersion, if necessary, a release agent may be previously contained in the binder resin particle dispersion.

[0142] The median diameter of the binder resin particles in the dispersion on a volume basis is preferably in the range of 50 to 300 nm. The median diameter of the binder resin particles in the dispersion on a volume basis can be measured by the dynamic light scattering method using "Microtrac UPA-150" (manufactured by Nikkiso Co., Ltd.).

[0143] (1B) Step of preparing the colorant particle dispersion This step of preparing the colorant particle dispersion is a step of dispersing the colorant in a particulate state in an aqueous medium to prepare a dispersion of the colorant particles.

[0144] The dispersion of the colorant can be carried out using mechanical energy. The median diameter of the colorant particles in the dispersion on a volume basis is preferably in the range of 10 to 300 nm, and more preferably in the range of 50 to 200 nm.

[0145] The volume-based median diameter of the colorant particles in the dispersion can be measured by the dynamic light scattering method using "Microtrac UPA-150" (manufactured by Nikkiso Co., Ltd.) in the same manner as described above.

[0146] (1C) Release agent particle dispersion preparation step This release agent particle dispersion preparation step is a step of dispersing a release agent in a particulate form in an aqueous medium to prepare a dispersion of release agent particles.

[0147] The dispersion of the release agent can be carried out 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.

[0148] The volume-based median diameter of the release agent particles in the dispersion can be measured, for example, by a laser diffraction particle size distribution analyzer LA-750 (manufactured by Horiba, Ltd.).

[0149] (Aqueous medium) (1A) to (1C) The aqueous medium used in the steps is water or an aqueous medium containing water as the main component (50% by mass or more) and containing water-soluble solvents such as alcohols and glycols, and optional components such as surfactants and dispersants. Preferably, an aqueous medium obtained by mixing water and a surfactant is used.

[0150] Examples of the above water-soluble solvents include methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, tetrahydrofuran, etc. Among these, alcohols such as methanol, ethanol, isopropanol, and butanol, which are organic solvents that do not dissolve polymers, are preferred.

[0151] Examples of surfactants include cationic surfactants, anionic surfactants, nonionic surfactants, etc. Examples of cationic surfactants include dodecylammonium chloride, dodecylammonium bromide, dodecyltrimethylammonium bromide, dodecylpyridinium chloride, dodecylpyridinium bromide, hexadecyltrimethylammonium bromide, etc. Examples of anionic surfactants include fatty acid soaps such as sodium stearate and sodium dodecanoate, sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, etc. Examples of nonionic surfactants include polyoxyethylene dodecyl ether, polyoxyethylene hexadecyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl ether, polyoxyethylene sorbitan monooleate ether, sucrose monodecanoate, etc.

[0152] Such surfactants can be used alone or in combination of two or more. Among the surfactants, anionic surfactants are preferably used, and more preferably sodium dodecylbenzenesulfonate and sodium dodecyl sulfate are used.

[0153] The addition amount of the surfactant 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, based on 100 parts by mass of the aqueous medium.

[0154] (2) The steps from the aggregation step to the external additive addition step (6) can be carried out according to various conventionally known methods.

[0155] The flocculant used in the (2) aggregation step is not particularly limited, but those selected from metal salts are preferably used.

[0156] Examples of the metal salt include monovalent metal salts such as salts of alkali metals such as sodium, potassium, and lithium; divalent metal salts such as calcium, magnesium, manganese, and copper salts; trivalent metal salts such as iron and aluminum salts, and the like.

[0157] Specific examples of the metal salt include sodium chloride, potassium chloride, lithium chloride, calcium chloride, magnesium chloride, zinc chloride, copper sulfate, magnesium sulfate, manganese sulfate, polyaluminum chloride, and the like. Among these, divalent or trivalent metal salts are particularly preferably used because aggregation can proceed with a smaller amount. These can be used alone or in combination of two or more.

[0158] [Developer] When the toner of the present invention contains a magnetic material and is used as a one-component magnetic toner, or when it is mixed with so-called carrier particles and used as a two-component developer, or when a non-magnetic toner is used alone, etc., it can be preferably used in any case.

[0159] Examples of the magnetic material that can be used include magnetite, γ - hematite, or various ferrites.

[0160] As the carrier particles constituting the two-component developer, magnetic particles made of conventionally known materials such as metals such as iron, steel, nickel, cobalt, ferrite, and magnetite, and alloys of these metals with metals such as aluminum and lead can be used.

[0161] As the carrier particles, it is preferable to use coated carrier particles in which the surface of the magnetic particles is coated with a coating agent such as a resin, or so-called resin-dispersed carrier particles in which magnetic powder is dispersed in a binder resin.

[0162] The resin for coating is not particularly limited, and for example, olefin resin, styrene resin, styrene-acrylic resin, silicone resin, polyester resin, or fluororesin is used.

[0163] Also, as the resin for constituting the resin-dispersed carrier particles, there is no particular limitation and known resins can be used. For example, acrylic resins, styrene-acrylic resins, polyester resins, fluororesins, phenolic resins, etc. can be used.

[0164] The volume-based median diameter of the carrier particles is preferably in the range of 20 to 100 μm, and more preferably in the range of 25 to 60 μm.

[0165] The volume-based median diameter of the carrier particles can typically be measured by a laser diffraction particle size distribution measuring device "HELOS" (manufactured by SYMPATEC) equipped with a wet disperser.

[0166] The mixing amount of the toner particles with respect to the carrier particles is preferably in the range of 2 to 10% by mass with the total mass of the toner particles and the carrier particles being 100% by mass.

[0167] [Image forming method] The toner of the present invention can be suitably used in an image forming method including a fixing step by a heat pressure fixing method that can apply pressure and heat. In particular, it can be suitably used in an image forming method in which the fixing temperature in the fixing step is set to a relatively low fixing temperature in the range of 80 to 110°C, preferably 80 to 95°C, at the surface temperature of the heating member in the fixing nip portion.

[0168] Furthermore, it can also be suitably used in a high-speed fixing image forming method in which the fixing linear speed is in the range of 200 to 600 mm / sec.

[0169] In this image forming method, specifically, using the toner of the present invention as described above, for example, an electrostatic charge image formed on a photoreceptor is developed to obtain a toner image, and this toner image is transferred onto an image support. Thereafter, the toner image transferred onto the image support is fixed onto the image support by a fixing process using a thermo-pressure fixing method, thereby obtaining a printed matter on which a visible image is formed.

[0170] In addition, the toner of the present invention can be used in a monochrome image forming method or a full-color image forming method.

[0171] In a full-color image forming method, it can be applied to any image forming method such as a four-cycle image forming method constituted by four color developing devices respectively related to yellow, magenta, cyan, and black, and one photoreceptor, or a tandem image forming method in which image forming units each having a color developing device and a photoreceptor related to each color are mounted separately for each color.

Example

[0172] Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In the following examples, unless otherwise specified, the operations were carried out at room temperature (25 °C). Also, unless otherwise specified, “%” and “parts” respectively mean “mass %” and “parts by mass”.

[0173] The first monomers M1 to M5 and the second monomers M6 to M10 used in the examples are as follows.

[0174]

Chemical formula

[0175]

Chemical formula

[0176] [Manufacture of Toner 1] <Preparation of Binder Resin Particle Dispersion Liquid 1> Into a 5 L stainless steel kettle (SUS kettle) equipped with a stirring device, a temperature sensor, a cooling pipe, and a nitrogen introduction device, a surfactant solution prepared by dissolving 8 g of sodium dodecyl sulfate in 3 L of ion-exchanged water was charged, and while stirring at a stirring speed of 230 rpm under a nitrogen stream, the liquid temperature was raised to 80 °C.

[0177] To this surfactant solution, an initiator solution prepared by dissolving 10 g of potassium persulfate in 200 g of ion-exchanged water was added. After setting the temperature to 80 °C, the following monomer mixture was added dropwise over 100 minutes.

[0178] - Monomer mixture - First monomer M1 282 g Second monomer M6 290 g n-Butyl acrylate (nBA) 193 g Methacrylic acid (MAA) 40 g n-Octyl 3-mercaptopropionate 5.5 g

[0179] This system was polymerized by heating and stirring at 80 °C for 2 hours to prepare a binder resin particle dispersion 1.

[0180] When 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.), it was 115 nm.

[0181] Also, when the peak molecular weight of the polymer contained in the binder resin was measured as follows, it was 21100.

[0182] Using the apparatus "HLC-8220" (manufactured by Tosoh Corporation) and the column "TSKguardcolumn + TSKgel SuperHZM-M3 series" (manufactured by Tosoh Corporation), while maintaining the column temperature at 40 °C, tetrahydrofuran (THF) was flowed as a carrier solvent at a flow rate of 0.2 ml / min, and the measurement sample was dissolved in tetrahydrofuran to a concentration of 1 mg / ml under dissolution conditions of treating at room temperature (25 °C) for 5 minutes using an ultrasonic disperser.

[0183] Subsequently, it was processed with a membrane filter having a pore size of 0.2 μm to obtain a sample solution. 10 μl of this sample solution was injected into the apparatus together with the above carrier solvent, and detected using a refractive index detector (RI detector), and determined from the molecular weight distribution of the measurement sample.

[0184] <Preparation of Colorant Particle Dispersion Liquid 1> Colorant: 10 parts by mass of carbon black 1.5 parts by mass of 20% anionic surfactant 90 parts by mass of ion-exchanged water

[0185] For the above colorant, carbon black (Mogul (registered trademark) L manufactured by Cabot Corporation) was used. For the above 20% anionic surfactant, a 20% aqueous solution of sodium dodecylbenzenesulfonate was used.

[0186] The above components were mixed and dispersed using an SC mill to obtain Colorant Particle Dispersion Liquid 1. When the volume-based median diameter of the colorant particles in the dispersion liquid was measured by the dynamic light scattering method using "Microtrac UPA-150" (manufactured by Nikkiso Co., Ltd.), it was 155 nm.

[0187] <Preparation of Release Agent Particle Dispersion Liquid 1> 100 parts by mass of behenyl behenate 5 parts by mass of sodium dodecyl sulfate 240 parts by mass of ion-exchanged water

[0188] The above components were dispersed in a round stainless steel flask using a homogenizer "Ultra Turrax (registered trademark) T50" (manufactured by IKA Corporation) for 10 minutes, and then dispersed using a pressure discharge type homogenizer to obtain Release Agent Particle Dispersion Liquid 1. When the volume-based median diameter of the release agent particles in the dispersion liquid was measured by a laser diffraction particle size distribution analyzer LA-750 (manufactured by Horiba, Ltd.), it was 530 nm.

[0189] <Preparation of Toner Base Particle Dispersion Liquid 1> 1237 parts by mass of the binder resin particle dispersion 42 parts by mass of the colorant particle dispersion 1 18 parts by mass of the release agent particle dispersion 1 1.8 parts by mass of aluminum polychloride 600 parts by mass of ion-exchanged water

[0190] The above components were mixed and dispersed in a round stainless steel flask using a homogenizer "Ultra Turrax (registered trademark) T50" (manufactured by IKA), and then heated to 55°C with stirring in an oil bath for heating. After holding at 55°C for 30 minutes, it was confirmed that aggregated particles with a median diameter (D50) of 4.8 μm based on volume were generated in the solution.

[0191] Furthermore, when the temperature of the oil bath for heating was raised and held at 56°C for 2 hours, the median diameter (D50) based on volume became 5.9 μm.

[0192] Thereafter, 1 mol / L of sodium hydroxide was added to the system to adjust the pH of the system to 5.0 at 56°C. Then, the round stainless steel flask was sealed using a magnetic seal and heated to 98°C while continuing stirring. By continuing stirring for 6 hours, the fusion (bonding) between the binder resin particles was completed, and toner mother particle dispersion 1 was prepared. The median diameter (D50) based on volume of the toner mother particles in the dispersion was 6.1 μm.

[0193] <Washing and Drying Process> Toner mother 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 mother particles.

[0194] The wet cake was washed with ion-exchanged water at 45°C using the above basket-type centrifuge until the electrical conductivity of the filtrate reached 5 μS / cm, and then transferred to a "Flash Jet Dryer" (manufactured by Seishin Enterprise Co., Ltd.) and dried until the moisture content became 0.5% by mass to obtain toner mother particles.

[0195] <External additive treatment of toner base particles> To 100 parts by mass of the toner base particles obtained above, 1 part by mass of hydrophobic silica (number average primary particle diameter = 12 nm) and 0.3 part by mass of hydrophobic titania (number average primary particle diameter = 20 nm) were added, and the mixture was mixed with a Henschel mixer (registered trademark) to perform external additive treatment, thereby producing Toner 1.

[0196] [Production of Toners 2 to 16] In the production of Toner 1, among the monomer mixtures, 5.5 g of n-octyl-3-mercaptopropionate was the same, and the combinations and addition amounts [mass%] of the other monomers were changed as shown in Table I below to produce Toners 2 to 16. In Table I below, nBA represents n-butyl acrylate, 2EHA represents 2-ethylhexyl acrylate, MAA represents methacrylic acid, and AA represents acrylic acid.

[0197] Note that the volume-based median diameter of the binder resin particles in the binder resin particle dispersion of each toner was 120 nm.

[0198] Also, the peak molecular weight of the polymer contained in the binder resin of each toner was as shown in Table I below.

[0199] [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 a methyl methacrylate-cyclohexyl methacrylate copolymer resin (volume-based median diameter of primary particles: 85 nm) were placed in a horizontal stirring blade type high-speed stirring device, and after mixing for 15 minutes under the conditions of a peripheral speed of the stirring blade: 8 m / s and a temperature: 30 °C, the temperature was raised to 120 °C and stirring was continued for 4 hours. Then, it was cooled, and fragments of the methyl methacrylate-cyclohexyl methacrylate copolymer resin were removed using a 200-mesh sieve to produce a resin-coated carrier.

[0200] This resin-coated carrier was mixed with each of the above toners 1 to 16 so that the concentration of the toner was 7% by mass based on the total mass of the toner and the carrier, and two-component developers 1 to 16 were prepared.

[0201] [Evaluation] The following evaluation items were evaluated using the two-component developers 1 to 16. The evaluation results are as shown in Table I below. In Table I, in the case of the two-component developers (No.) 2, 5, 10 to 13, read "the present invention" in the respective remarks columns as "reference example".

[0202] (1) Fold fixing property As an image forming apparatus, a commercially available multifunction machine "bizhub PRO (registered trademark) C6500" (manufactured by Konica Minolta, Inc.) was used. Each of the above two-component developers 1 to 16 was mounted on this apparatus. The surface temperature of the fixing heating member in the fixing means of the heat roll fixing method was set to 150°C, and in an environment of normal temperature and humidity (temperature 20°C, relative humidity 50%RH), as an image support, a thick paper with a weight of 350 g / m 2 was used to form an image, and a solid image on which 5 g / m 3 of toner was fixed was obtained as a visible image.

[0203] Thereafter, the fixed solid image was folded using a folding machine, 0.35 MPa of air was blown onto it, and the state of the fold was evaluated in five grades as follows with reference to a limit sample. If the rank was 3 or higher, it was judged as qualified.

[0204] Rank 5: No peeling at the fold Rank 4: Slight peeling along the fold Rank 3: Partial peeling along the fold Rank 2: Thin linear peeling along the fold Rank 1: Thick linear peeling along the fold

[0205] (2) Measurement of adhesion force Each of the above two-component developers 1 to 16 was mounted on "bizhub PRESS C1070 (manufactured by Konica Minolta)" to measure the adhesion force.

[0206] Specifically, in an environment of normal temperature and humidity (temperature 20°C, humidity 50%RH), on the "OK Top Coat Paper 157 g / m 2 " (manufactured by Oji Paper Co., Ltd.), after setting the toner adhesion amount to 8.0 g / m 2 , the lower roller temperature was set to 70°C, and a single-sided solid image was output in double-sided output mode, with 5 sheets output in A3 size. 500 A3 sheets were placed on top of the output paper bundle and left for 2 hours. It was placed on a flat table, and a tape was attached to the tip of the top sheet and slowly slid horizontally.

[0207] At this time, for the sheets below the second sheet from the top, fix them to the table so that they do not move. The force required to slide the sheet was measured only with a spring. This measurement was repeated 4 times in order from the top, and the average value of the force [N] indicated by the spring was taken as the sticking force. When the sticking force was 2.0 N or less, it was regarded as a practical level.

[0208] (3) Heat-resistant storage stability Regarding the above two-component developers 1 to 16, 0.5 g of each was taken into a 10 mL glass bottle with an inner diameter of 21 mm, the lid was closed, and it was shaken 600 times at room temperature with a tap denser KYT-2000 (manufactured by Seishin Enterprise Co., Ltd.). Then, it was left for 2 hours in an environment of 55°C and 35%RH with the lid removed.

[0209] Next, the above two-component developer after standing was placed on a 48-mesh (aperture 350 μm) sieve, taking care not to crush the aggregates of the two-component developer, set on a powder tester (manufactured by Hosokawa Micron Corporation), fixed with a press bar and a knob nut, adjusted to a vibration intensity with a feed width of 1 mm, and vibrated for 10 seconds.

[0210] After that, the mass of the two-component developer remaining on the sieve was measured, and the toner aggregation rate At (mass %) was calculated by the following formula. At [mass %] = (mass of the two-component developer remaining on the sieve [g]) / 0.5 [g] × 100

[0211] From the calculated toner aggregation rate At, the heat-resistant storage stability of the two-component developer was evaluated according to the following criteria. If it was ◎, ○, or △, it was considered qualified as having no practical problems.

[0212] ◎: The toner aggregation rate At is less than 15% by mass (the heat-resistant storage stability of the developer is extremely good) ○: The toner aggregation rate At is 15% by mass or more and less than 20% by mass (the heat-resistant storage stability of the developer is good) △: The toner aggregation rate At is 20% by mass or more and less than 25% by mass (the heat-resistant storage stability of the developer is slightly poor) ×: The toner aggregation rate At is 25% by mass or more (the heat-resistant storage stability of the developer is poor and it cannot be used)

[0213]

Table 1

[0214] From the above results, it can be seen that the electrostatic charge image developing toner of the present invention contains a polymer having structural units represented by the general formula (1) and the general formula (2), and can suppress electrostatic sticking of printed matter while satisfying heat-resistant storage stability and low-temperature fixability.

Claims

1. An electrostatic charge image developing toner containing toner base particles containing a binder resin and a colorant, wherein the toner base particles contain, as the binder resin, at least a polymer having a first structural unit represented by the following general formula (1) and a polymer having a second structural unit represented by the following general formula (2), or a copolymer having the first structural unit and the second structural unit, and a constituent ratio X represented by the following formula (I) is in the range of 25 to 75% by mass An electrostatic charge image developing toner characterized by the above. Formula (I): X [% by mass] = W1 / (W1 + W2) × 100 W1: Mass of the first structural unit in the total binder resin W2: Mass of the second structural unit in the total binder resin 【Chemical 1】 [In general formula (1), R １ represents a hydrogen atom or an alkoxy group having 1 to 3 carbon atoms. ] 【Chemical 2】 [In general formula (2), R ２ represents a hydrogen atom. ]

2. The electrostatic charge image developing toner according to claim 1, wherein the toner base particles contain, as the binder resin, a copolymer having the first structural unit and the second structural unit.

3. The electrostatic charge image developing toner according to claim 1 or claim 2, characterized by the above. R in the general formula (1) １ represents a hydrogen atom or a methoxy group

4. The electrostatic charge image developing toner according to any one of claims 1 to 3, characterized by the above. R in the general formula (1) １ represents a methoxy group

5. The electrostatic charge image developing toner according to any one of claims 1 to 4, wherein the copolymer further has a third structural unit different from the first structural unit and the second structural unit.

6. The electrostatic charge image developing toner according to any one of claims 1 to 4, wherein the third structural unit is at least a structural unit derived from an acrylate ester or a methacrylate ester.

7. The electrostatic charge image developing toner according to claim 5, wherein the third structural unit is at least a structural unit derived from acrylic acid, n-butyl acrylate, 2-ethylhexyl acrylate, or methacrylic acid.

8. A method for producing an electrostatic charge image developing toner containing toner base particles containing a binder resin and a colorant, the method comprising a step of copolymerizing at least a first monomer having a structure represented by the following general formula (3) and a second monomer having a structure represented by the following general formula (4) to prepare a particle dispersion of the binder resin, and a constituent ratio X represented by the following formula (I) is in the range of 25 to 75% by mass A method for producing an electrostatic charge image developing toner characterized by the above. Formula (I): X [% by mass] = W1 / (W1 + W2) × 100 W1: Mass of the first monomer W2: Mass of the second monomer ​ ​ ​ ​ 【Chemical Formula 3】 [In general formula (3), R １ represents a hydrogen atom or an alkoxy group having 1 to 3 carbon atoms. ] 【Chemical Formula 4】 [In general formula (4), R ２ represents a hydrogen atom. ]

Images