JP6780446B2 - Manufacturing method of toner for static charge image development and toner for static charge image development - Google Patents

Description

The present invention relates to a toner for developing an electrostatic charge image and a method for producing a toner for developing an electrostatic charge image. More specifically, the present invention relates to an electrostatic charge image developing toner or the like capable of forming an image having a high specular reflectance.

Conventionally, the toner used in the electrophotographic image forming apparatus contains a metal to give a gloss to the finished image.

For example, Patent Document 1 discloses a technique for incorporating flat-plate-shaped glittering particles into a toner. In the technique disclosed in Patent Document 1, metal powders such as aluminum, brass, bronze, nickel, stainless steel, and zinc are used as the flat plate-like bright particles.
Patent Document 2 discloses a technique for incorporating fine particles of a mold release agent composition having an average particle size in the range of 1.1 to 1.5 μm, which is composed of wax and a low melting point metal, in a toner.
Patent Document 3 discloses toner particles in which a low melting point metal is added as an external additive and the low melting point metal is adhered to the outermost shell of the toner matrix particles.
Patent Document 4 discloses a technique for producing toner matrix particles containing a low melting point metal atom by a crushing method.

However, in recent years, with the diversification of applications for electrophotographic images, there is a demand for images showing high normal reflectance such as silver mirrors, but the above technology has insufficient regular reflectance and specular reflection. The formation of the image to be performed cannot be realized.

For example, in metal powders such as aluminum, brass, bronze, nickel, stainless steel, and zinc used in the technique disclosed in Patent Document 1, the lowest melting point of zinc is 419 ° C., which is melted in the electrophotographic process. This is not possible, and scattering depending on the orientation direction of the metal particles occurs. Therefore, with the toner disclosed in Patent Document 1, it is not possible to obtain an image having a higher specular reflectance.

Further, in the toner disclosed in Patent Document 2, the average particle size of the release agent composition fine particles composed of wax and a low melting point metal is 1.1 to 1.5 μm, and the low melting point metal contained therein is further. small. Since the particle size of the toner particles is usually about 6 to 8 μm, the amount of low melting point metal contained in the toner particles is small. Therefore, in the toner disclosed in Patent Document 2, when heat-fixed, gaps are formed between the low melting point metals, and as a result, an image having a high specular reflectance cannot be obtained.

In addition, low melting point metals such as gallium and indium are electronegative substances, and when used as an external agent for toner made of a binder resin, the outermost shell of the toner matrix particles has an electronegative substance, and the toner It becomes impossible to develop because the chargeability of the above cannot be ensured. Therefore, the toner disclosed in Patent Document 3 cannot obtain an image having a high specular reflectance.

The toner disclosed in Patent Document 4 is produced by a crushing method. In such toner matrix particles, it is conceivable that the low melting point metal is exposed on the surface (crushed surface) of the toner matrix particles. When the low melting point metal is exposed, a voltage leak (hereinafter, also referred to as “voltage leak”) occurs, and the surface of the toner particles is not triboelectrically charged. As a result, the toner cannot be charged. Cannot develop. Therefore, the toner disclosed in Patent Document 4 cannot obtain an image having a high specular reflectance.
Further, since the low melting point metal (alloy) used in the toner disclosed in Patent Document 4 has a high oxidation-reduction potential calculated from its atomic weight ratio, it is difficult to form an oxide film on the low melting point metal surface, and as a result, Low melting point metal is hard to get wet and spread. For this reason as well, the toner disclosed in Patent Document 4 cannot obtain an image having a high positive reflectance.

Japanese Unexamined Patent Publication No. 2012-163695 Japanese Unexamined Patent Publication No. 11-174728 Japanese Unexamined Patent Publication No. 8-6283 Japanese Unexamined Patent Publication No. 2012-68403

The present invention has been made in view of the above problems and situations, and a solution to the present invention is to provide a toner for static charge image development or the like capable of forming an image having a high specular reflectance.

In the process of examining the cause of the above problem in order to solve the above problems, the present inventor uses low melting point metal particles whose melting point, particle size and oxidation-reduction potential satisfy specific conditions, and a binder resin as main components. In the present invention, it has been found that if the toner matrix particles having the outermost shell and the toner matrix particles are used, the low melting point metal is melted and widely wetted and spread in the electrophotographic process, so that an image having high reflectance can be obtained. I arrived.
That is, the above problem according to the present invention is solved by the following means.

1. 1. A toner for static charge image development containing at least toner matrix particles composed of low melting point metal particles and a binder resin.
The main component of the outermost shell of the toner matrix particles is the binder resin.
The outermost shell does not contain the low melting point metal particles,
The melting point of the low melting point metal is 150 ° C. or lower.
The particle size of the low melting point metal particles is 2 μm or more.
A toner for static charge image development, wherein the standard oxidation-reduction potential of the low melting point metal calculated from the atomic weight ratio is −0.20 V or less.

2. The first item is characterized in that the low melting point metal contains one kind of metal selected from gallium, tin, zinc, aluminum, bismuth, germanium, silicon and indium, or an alloy composed of a plurality of kinds of metals. The above-mentioned static charge image developing toner.

3. 3. The toner for developing an electrostatic charge image according to item 1 or 2, wherein the melting point of the low melting point metal is in the range of 50 to 150 ° C.

4. The toner for static charge image development according to any one of items 1 to 3, wherein the toner matrix particles further contain a release agent or a charge control agent.

5. The toner for developing an electrostatic charge image according to any one of items 1 to 4, wherein an external additive is added.

6. The item according to any one of items 1 to 5, wherein the volume ratio of the low melting point metal to the total volume of the electrostatic charge image developing toner is in the range of 10 to 50 vol%. Toner for static charge image development.

7. A method for producing an electrostatic charge image developing toner according to any one of the items 1 to 6, wherein the electrostatic charge image developing toner is produced.
A method for producing a toner for static charge image development, which comprises a step of coating the outside of the low melting point metal particles with the binder resin in a latex.

8. A method for producing an electrostatic charge image developing toner according to any one of the items 1 to 6, wherein the electrostatic charge image developing toner is produced.
Manufacture of a toner for static charge image development, which comprises a step of coating the outside of the low melting point metal particles with the binding resin while mixing the low melting point metal and the binding resin in a gas phase. Method.

9. A method for producing an electrostatic charge image developing toner according to any one of the items 1 to 6, wherein the electrostatic charge image developing toner is produced.
A method for producing a toner for static charge image development, which comprises a step of coating the outside of the low melting point metal with the binder resin using a microchannel.

By the above means of the present invention, it is possible to provide a toner for static charge image development or the like capable of forming an image having a high specular reflectance.
The mechanism of expression or action of the effects of the present invention has not been clarified, but it is inferred as follows.

The present inventor presents that metal particles having a melting point of 150 ° C. or lower (hereinafter, also referred to as "low melting point metal according to the present invention" or simply "low melting point metal") are melted by an electrophotographic process. It is considered that the orientation-dependent scattering of the metal does not occur. That is, since the toner of the present invention uses a low melting point metal having a melting point of 150 ° C. or lower, it is considered that an image having a higher specular reflectance can be formed.

Further, according to the present inventor, if the particle size of the low melting point metal particles is 2 μm or more, the amount of the low melting point metal contained in the toner matrix particles becomes an appropriate amount, and when the low melting point metal is thermally fixed, a gap is formed between the low melting point metals. I don't think I can. As a result, it is considered that the toner of the present invention can form an image having a high specular reflectance.

Further, gallium and indium are electronegative substances, but as in the present invention, the outermost shell of the toner matrix particles does not contain these low melting point metal particles according to the present invention. As a result, in the toner of the present invention, since the low melting point metal particles which are electronegative substances are not exposed, voltage leakage does not occur and the chargeability of the toner can be ensured. As a result, the toner can be developed favorably, and thus is high. It is considered that an image having a specular reflectance can be formed.

Further, in the toner of the present invention, since the low melting point metal (alloy) has an oxidation-reduction potential calculated from the atomic weight ratio of −0.20V or less, an oxide film is likely to be formed on the surface of the low melting point metal particles. , Low melting point metal is easy to get wet and spread. Therefore, it is considered that the toner of the present invention does not have a gap between the low melting point metals when it is heat-fixed. For this reason as well, it is considered that the toner of the present invention can form an image having a high positive reflectance.

Schematic diagram for explaining the membrane emulsification method according to the present invention. Schematic cross-sectional view showing an example of toner matrix particles according to the present invention. Schematic cross-sectional view showing another example of toner matrix particles according to the present invention. Schematic diagram showing an example of a microchannel according to the present invention Schematic cross-sectional view showing an example of an image forming apparatus capable of preferably using the toner according to the present invention.

The static charge image development toner of the present invention is a static charge image development toner containing at least toner matrix particles composed of low melting point metal particles and a binder resin, and is the main component of the outermost shell of the toner matrix particles. However, the binder resin, the outermost shell does not contain the low melting point metal particles, the melting point of the low melting point metal is 150 ° C. or lower, and the particle size of the low melting point metal particles is 2 μm. As described above, the standard oxidation-reduction potential of the low melting point metal calculated from the atomic weight ratio is −0.20 V or less. This feature is a technical feature common to or corresponding to the following embodiments . As a result, the present invention can obtain the effect that an image having a high positive reflectance can be formed.

In the present invention, the low melting point metal preferably contains one kind of metal selected from gallium, tin, zinc, aluminum, bismuth, germanium, silicon and indium, or an alloy composed of a plurality of kinds of metals. This makes it possible to form an image having a higher specular reflectance.

In the present invention, the melting point of the low melting point metal is preferably in the range of 50 to 150 ° C. As a result, a stable image on the printed surface can be formed while having a high specular reflectance.

In the present invention, it is preferable that the toner matrix particles further contain a mold release agent or a charge control agent. This makes it possible to prevent the toner from sticking to the roller during image crimping.

In the present invention, it is preferable that an external additive is added. Thereby, fluidity, chargeability, cleanability and the like can be improved.

In the present invention, the volume ratio of the low melting point metal to the total volume of the electrostatic charge image developing toner is preferably in the range of 10 to 50 vol%. As a result, good development can be achieved while obtaining a high specular reflectance.

As a method for producing the static charge image developing toner of the present invention, it is preferable to have a step of coating the outside of the low melting point metal particles with the binder resin in the latex. This makes it possible to suitably produce a toner capable of forming an image having a high specular reflectance.

As a method for producing the static charge image developing toner of the present invention, the low melting point metal particles and the binder resin are mixed in a gas phase, and the low melting point metal particles are produced. It is preferable to have a step of coating the outside with the binder resin. This makes it possible to suitably produce a toner capable of forming an image having a high specular reflectance.

The method for producing the static charge image developing toner of the present invention includes a step of coating the outside of the low melting point metal particles with the binder resin using a microchannel. Is preferable. This makes it possible to suitably produce a toner capable of forming an image having a high specular reflectance.

Hereinafter, the present invention, its constituent elements, and modes and modes for carrying out the present invention will be described in detail. In the present application, "~" is used to mean that the numerical values described before and after the value are included as the lower limit value and the upper limit value.

≪Overview of Toner for Static Charge Image Development≫
The static charge image development toner of the present invention is a static charge image development toner containing at least toner matrix particles composed of low melting point metal particles and a binder resin, and is the main component of the outermost shell of the toner matrix particles. However, the binder resin has a melting point of the low melting point metal of 150 ° C. or less, the particle size of the low melting point metal particles is 2 μm or more, and the standard of the low melting point metal calculated from the atomic weight ratio. It is characterized in that the oxidation-reduction potential is −0.20 V or less.

[Low melting point metal particles]
The low melting point metal forming the low melting point metal particles is not particularly limited as long as it can realize the above melting point and the standard oxidation-reduction potential, but among gallium, tin, zinc, aluminum, bismuth, germanium, silicon and indium. It is preferable to contain one selected metal or an alloy composed of a plurality of metals because the melting point and the standard oxidation-reduction potential can be easily realized, and thus an image having a higher positive reflectance can be formed. Further, the low melting point metal particles may contain other elements such as other metals, inorganic compounds and organic compounds as long as the effects of the present invention are not hindered, in addition to the above low melting point metal.
If the redox potential is −0.20 V or less, an oxide film is likely to be formed on the surface and the film is easily wetted and spread, so that a wide reflective film can be obtained. The lower the redox potential, the easier it is to form an oxide film, and the wettability is improved by interaction with the substrate, which is preferable. However, those having an oxidation-reduction potential that is too low may have high reactivity and may hinder the expression of the function as a toner. Therefore, in reality, those having an oxidation-reduction potential of −2.0 V or higher are preferable.

The melting point of the low melting point metal is preferably in the range of 50 to 150 ° C.
If the melting point of the low melting point metal is 150 ° C. or less, it can be sufficiently heated by the thermocompression bonding process using electrophotographic, and as a result, the low melting point metal can be sufficiently integrated, and an image having high reflectance can be obtained. On the other hand, if the melting point of the low melting point metal is 50 ° C. or higher, it does not become a liquid at room temperature and the printed surface is stable.

Further, the volume ratio of the low melting point metal to the total volume of the static charge image developing toner is preferably in the range of 10 to 50 vol%.
When the volume ratio of the low melting point metal to the total volume of the static charge image developing toner is 10 vol% or more, the low melting point metals can be suitably combined, and as a result, an image having a high specular reflectance can be obtained.
On the other hand, when the volume ratio is 50 vol% or less, it is possible to prevent the thickness of the outermost shell of the toner base particles from becoming too thin, and as a result, the chargeability can be improved and, by extension, good development can be realized.

The particle size of the low melting point metal particles is 2 μm or more. The particle size of the low melting point metal particles is preferably in the range of 2 to 15 μm. When the particle size of the low melting point metal particles is 2 μm or more, the metal particles can be suitably combined with each other in the heat fixing process, and high reflectance can be obtained. On the other hand, when the particle size is 15 μm or less, the toner diameter does not become too large as a result, and a high-resolution image can be obtained.

(Melting point of low melting point metal)
The melting point of the low melting point metal can be determined by a known method based on the phase diagram.

(Diameter of low melting point metal particles)
The particle size of the low melting point metal particles is determined by, for example, about 20 low melting point metal particles randomly selected in an electron micrograph using a scanning electron microscope (SEM) "JSM-7401F" (manufactured by JEOL Ltd.). , Each of which has a particle size, and can be obtained as an average value of these 20 low melting point metal particles.

(Measuring method of standard redox potential)
The standard oxidation-reduction potential of the low-melting-melt metal element according to the present invention can be obtained from the oxidation-reduction potential of each element constituting the low-melting-melt metal and its mass ratio.
As the oxidation-reduction potential of each element, a known one can be used. For example, the "standard oxidation-reduction potential" described in the 5th Edition Electrochemical Handbook (edited by the Electrochemical Association) can be used.
As a specific method for calculating the standard oxidation-reduction potential, for example, when the low melting point metal [A] (Ga: 70% by mass, Sn: 30% by mass) described in the examples is converted into an atomic weight ratio, Ga: 79. It becomes .9 atm%, Sn: 20.1 atm%, and when this atomic weight ratio is multiplied by the oxidation-reduction potential of each metal, Ga: 0.799 × (−0.529), Sn: 0.201 × (-0. .138). When these are added together, the redox potential of the low melting point metal [A] is −0.450.

<Manufacturing method of low melting point metal particles>
The method for producing the low melting point metal particles is not particularly limited as long as the low melting point metal can be made into particles, and a known method can be used. For example, the low melting point metal particles are manufactured by a membrane emulsification method or an ultrasonic irradiation method. be able to.

(Membrane emulsification method)
The method for obtaining low melting point metal particles by using the membrane emulsification method is not particularly limited, and a known method can be adopted. Specifically, for example, the low melting point metal 310 is immersed in a solvent 312 to which a protective agent is added, and this is passed through an emulsified film 320 having pores 321 to obtain a suspension 314. The low melting point metal particles 322 can be obtained by purifying the obtained suspension 314 by centrifugation (see FIG. 1).
The pore diameter is preferably 1 to 5 μm.

(Ultrasonic irradiation method)
The method for obtaining low melting point metal particles by using the ultrasonic irradiation method is not particularly limited, but specifically, for example, the following may be used.
First, the molten low melting point metal is immersed in a solvent to which a protective agent is added or the like, and ultrasonic irradiation is performed to obtain a suspension. Low melting point metal particles can be obtained by purifying the obtained suspension by centrifugation.

(Protective agent)
A protective agent can be used in the above-mentioned membrane emulsification method or ultrasonic irradiation method. This is preferable because the particles can be stably dispersed in the solution.
Such protective agents include cationic surfactants such as sodium lauryl sulfate (SDS), alkyltrimethylammonium salt, dialkyldimethylammonium salt, alkylbenzyldimethylammonium salt, fatty acid salt, monoalkylsulfate, alkylpolyoxy. Anionic surfactants such as ethylene sulfate, alkylbenzene sulfonates, monoalkyl phosphates, amphoteric surfactants such as alkyldimethylamine oxides, alkylcarboxybetaines, alkylthiols such as dodecanethiol, dodecylamine, Alkylamines such as nonylamines, fatty acids such as dodecanoic acid and undecanoic acid, sucrose fatty acid esters sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, fatty acid surfactants such as fatty acid alkanolamides, polyoxyethylene alkyl ethers Examples thereof include higher alcohol-based surfactants, amino acids such as tryptophan and histidine, and amino acid-based surfactants such as alkylamino fatty acid salts.

(solvent)
The solvent that can be used in the film emulsification method or the ultrasonic irradiation method is not limited, but the boiling point is preferably equal to or higher than the melting point of the low melting point metal. For example, non-polar organic solvents such as water, toluene and hexane, alcohol-based organic solvents such as methanol and ethanol propanol, halogen-based solvents such as chloroform and dichloromethane tetrachloride, dimethylformamide (DMF), N-methylpyrrolidone ( An aprotonic polar organic solvent such as NMP) or tetrahydrofuran (THF) can be used.

<External agent>
It is preferable that an external additive is added to the toner of the present invention for the purpose of improving fluidity and chargeability as long as the effect is not impaired. Examples of the external additive include fatty acid metal, inorganic oxide fine particles such as silica fine particles (small diameter external additive) having a particle size of less than 30 nm, alumina fine particles, and titanium oxide fine particles, and inorganic substances such as strontium titanate and zinc titanate. Known examples include, but are not limited to, inorganic fine particles such as titanic acid compound fine particles.

[Toner matrix particles]
The toner base particles according to the present invention are composed of at least low melting point metal particles and a binder resin.
Further, in the toner base particles according to the present invention, the main component of the outermost shell is a binder resin. The toner base particles according to the present invention may contain an internal additive such as a colorant in addition to the binder resin.
Further, the toner base particles may have a core-shell structure including at least core particles and a shell that covers the surface of the core particles. In this case, it may have a plurality of core particles, and for example, it may contain a plurality of core particles made of low melting point metal particles.
Specifically, for example, as shown in FIG. 2, one low melting point metal particle 110 is used as a core particle, and the surface of the low melting point metal particle 110 is coated with a shell 120 made of a binder resin. The configuration may be as follows. Further, for example, as shown in FIG. 3, a plurality of low melting point metal particles 210 are used as core particles, and the surface of the low melting point metal particles 210 is coated with a shell 220 made of a binder resin, such as toner base particles 200. It may be a configuration.
Further, it is preferable that the shell does not contain a low melting point metal and contains a binder resin as a main component, like the outermost shell described below.
The particle size of the toner matrix particles according to the present invention is preferably, for example, 2 to 20 μm in terms of volume-based median diameter, and more preferably 2 to 10 μm.

(Outermost shell)
The outermost shell is a portion of the toner matrix particles that is 90 to 95% or more outer of the particle size from the center.
The main component of the outermost shell is a binder resin. Here, the main component means that it contains 50% or more of the components constituting the outermost shell, preferably 70% or more, more preferably 80% or more, and particularly preferably 90% or more. ..
Further, the toner for developing an electrostatic charge image of the present invention is characterized in that the outermost shell of the toner matrix particles contained does not contain low melting point metal particles.

[Bundling resin]
The toner base particles according to the present invention can contain a known resin as the binder resin, and can contain, for example, a crystalline polyester resin or a styrene-acrylic resin. The styrene-acrylic resin referred to here is formed by addition polymerization of a styrene monomer which is a polymerizable monomer and a (meth) acrylic acid ester monomer. The styrene monomer contains, in addition to the styrene represented by the structural formula of CH ₂ = CH-C ₆ H _5, a structure having a known side chain or functional group in the styrene structure. Further, the (meth) acrylic acid ester monomer referred to here is an acrylic acid ester derivative or a methacrylic acid ester derivative in addition to the acrylic acid ester or methacrylic acid ester represented by CH ₂ = CHCOOR (R is an alkyl group). Etc., which contain an ester having a known side chain or functional group in the structure. Specific examples of the styrene monomer and the (meth) acrylic acid ester monomer capable of forming the styrene-acrylic resin are shown below, but those that can be used for forming the styrene-acrylic resin used in the present invention. Is not limited to the following.

Specific examples of the styrene monomer include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene, and 2,4-dimethylstyrene. , P-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene and the like. These styrene monomers can be used alone or in combination of two or more.

Specific examples of the (meth) acrylic acid ester monomer include methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, n-octyl acrylate, and 2-ethylhexyl acrylate. , Stearyl acrylate, lauryl acrylate, phenyl acrylate and other acrylic acid ester monomers; methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, Examples thereof include methacrylic ester such as stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate and dimethylaminoethyl methacrylate.
The content of the styrene-acrylic resin is preferably 70% by mass or more with respect to the total amount of the binder resin, and within this range, the effect of improving the chargeability can be sufficiently exhibited.

In addition to the above, a third polymerizable monomer can also be used as the polymerizable monomer. Examples of the third polymerizable monomer include acid monomers such as acrylic acid, methacrylic acid, maleic anhydride, and vinylacetic acid, and acrylamide, methacrylamide, acrylonitrile, ethylene, propylene, butylene vinyl chloride, N-vinylpyrrolidone, and the like. Examples include butadiene.
As the polymerizable monomer, a polyfunctional vinyl monomer may be further used. Examples of the polyfunctional vinyl monomer include diacrylates such as ethylene glycol, propylene glycol, butylene glycol and hexylene glycol, and dimethacrylates and trimethacrylates of tertiary and higher alcohols such as divinylbenzene, pentaerythritol and trimethylolpropane. And so on.

(Manufacturing method of styrene-acrylic resin)
The styrene-acrylic resin is preferably produced by an emulsion polymerization method. Emulsion polymerization can be obtained by dispersing and polymerizing a polymerizable monomer such as styrene or acrylic acid ester in an aqueous medium described later. It is preferable to use a surfactant in order to disperse the polymerizable monomer in the aqueous medium, and a known polymerization initiator and chain transfer agent can be used for the polymerization.

(Polymerization initiator)
As the polymerization initiator, various known polymerization initiators are preferably used. Specifically, for example, hydrogen peroxide, acetyl peroxide, cumil peroxide, -tert-butyl peroxide, propionyl peroxide, benzoyl peroxide, chlorobenzoyl peroxide, dichlorobenzoyl peroxide, bromomethylbenzoyl peroxide, etc. Lauroyl peroxide, ammonium persulfate, sodium persulfate, potassium persulfate, diisopropyl peroxycarbonate, di-t-butyl peroxide, tetraline hydroperoxide, 1-phenyl-2-methylpropyl-1-hydroperoxide, pertriphenylacetic acid-tert -Hydroperoxide, -tert-butyl peroxide, -tert-butyl peracetic acid, -tert-butyl perbenzoate, -tert-butyl perphenylacetate, -tert-butyl permethoxyacetate, excess N- (3-toluyl) Peroxides such as palmitate-tert-butyl; 2,2'-azobis (2-aminodipropane) hydrochloride, 2,2'-azobis- (2-aminodipropane) nitrate, 1,1'- Azo compounds such as azobis (sodium 1-methylbutyronitrile-3-sulfonate), 4,4'-azobis-4-cyanovaleric acid, poly (tetraethylene glycol-2,2'-azobisisobutyrate) And so on.

(Chain transfer agent)
The chain transfer agent is not particularly limited, and is, for example, a mercaptan such as octyl mercaptan, dodecyl mercaptan, alkyl mercaptan, t-dodecyl mercaptan; n-octyl-3-mercaptopropionate, stearyl-3-mercaptopropio. Mercaptopropionic acid such as nate, mercapto fatty acid ester, styrene dimer and the like can be used. These can be used individually by 1 type or in combination of 2 or more types.

<Crystalline polyester resin>
"Crystalline" in a crystalline polyester resin means that in differential scanning calorific value measurement (DSC), it has a clear heat absorption peak rather than a stepwise change in heat absorption amount, and specifically, a temperature rise rate of 10 (specifically, It means that the half price range of the heat absorption peak when measured at ° C / min) is within 10 (° C). On the other hand, an amorphous polyester resin (amorphous polymer) is used as a resin having a half-price width exceeding 10 ° C. or a resin showing a stepwise change in endothermic amount or not having a clear endothermic peak.

The crystalline polyester resin can be produced by a general polyester polymerization method in which an acid component and an alcohol component are reacted. Examples of the polymerization method include a direct polycondensation method and a transesterification method, and the polymerization method is appropriately used depending on, for example, the type of monomer.

The crystalline polyester resin can be produced, for example, at a polymerization temperature of 180 to 230 ° C. If necessary, the pressure inside the reaction system is reduced, and the above-mentioned monomers are reacted while removing water and alcohol generated by condensation. If the monomer is insoluble or incompatible at the reaction temperature, a high boiling point solvent may be added as a dissolution aid to dissolve the monomer. In the polycondensation reaction, the dissolution auxiliary solvent is distilled off. When a monomer having poor compatibility is present in the copolymerization reaction, for example, the monomer having poor compatibility and the acid or alcohol to be polycondensed with the monomer are condensed in advance and then polycondensed together with the main component. Good.

In addition, other binder resins may be contained, and examples thereof include styrene- (meth) acrylic resins and polyester resins, and partially modified modified polyester resins.

Specifically, the crystalline polyester resin has a molecular structure of a condensation polymerization product of a polyvalent carboxylic acid (acid component) and a polyhydric alcohol (alcohol component), and is synthesized by, for example, condensation polymerization of these. Is possible.
The polyvalent carboxylic acid may be one kind or more. Examples of the polyvalent carboxylic acid include aliphatic dicarboxylic acids, aromatic dicarboxylic acids, dicarboxylic acids having a double bond, trivalent or higher carboxylic acids, anhydrides thereof and lower alkyl esters thereof. Since the dicarboxylic acid having the double bond is radically crosslinked via the double bond, it is suitable from the viewpoint of preventing hot offset at the time of fixing the toner particles.

Examples of aliphatic dicarboxylic acids involved in the synthesis of crystalline polyester resins include oxalic acid, succinic acid, glutaric acid, adipic acid, speric acid, azelaic acid, sebacic acid, 1,9-nonandicarboxylic acid, 1,10-. Includes decandicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,14-tetradecandicarboxylic acid and 1,18-octadecanedicarboxylic acid.

Examples of aromatic dicarboxylic acids involved in the synthesis of crystalline polyester resins include phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid, malonic acid and mesaconic acid.
Examples of the dicarboxylic acid having a double bond include maleic acid, fumaric acid, 3-hexendioic acid and 3-octendioic acid. Of these, fumaric acid or maleic acid is preferable from the viewpoint of cost.
Examples of the trivalent or higher valent carboxylic acid include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid and 1,2,4-naphthalenetricarboxylic acid.

The polyhydric alcohol involved in the synthesis of the crystalline polyester resin may be one kind or more. Examples of such polyhydric alcohols include aliphatic diols and trihydric or higher alcohols. Of these, an aliphatic diol is preferable from the viewpoint of obtaining a crystalline polyester resin described later, and a linear aliphatic diol having a main chain portion having 7 to 20 carbon atoms is particularly preferable.

When the aliphatic diol is the linear aliphatic diol, the crystallinity of the polyester is maintained and the decrease in the melting temperature of the polyester is suppressed. Therefore, it is preferable from the viewpoint of obtaining the above-mentioned two-component developer having excellent toner blocking resistance, image storage property and low temperature fixability. Further, when the number of carbon atoms in the main chain portion of the linear aliphatic diol is 7 to 20, the melting point of the product when polycondensed with the aromatic dicarboxylic acid is suppressed to a low level, and low-temperature fixing is realized. Preferred from the point of view. In addition, it is practically easy to obtain materials. From these viewpoints, the carbon number of the main chain portion is more preferably 7 to 14.

Examples of aliphatic diols preferably used for the synthesis of the crystalline polyester resin include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 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 1,14-Eicosandecanediol. Of these, 1,8-octanediol, 1,9-nonanediol, or 1,10-decanediol is preferable from the viewpoint of availability.
Examples of the above trihydric or higher alcohols include glycerin, trimethylolethane, trimethylolpropane and pentaerythritol.

A chain transfer agent for adjusting the molecular weight of the obtained resin may be added to the monomer component for synthesizing the crystalline polyester resin. The chain transfer agent may be one kind or more, and is used in an amount capable of achieving the above object within the range in which the effect of the present embodiment is exhibited. Examples of such chain transfer agents include mercaptans such as 2-chloroethanol, octyl mercaptan, dodecyl mercaptan, t-dodecyl mercaptan and styrene dimers.

(Hybrid crystalline polyester resin)
The toner matrix particles according to the present invention are hybrid crystals in which at least a crystalline polyester polymerized segment and another polymerized segment (hereinafter, also referred to as “another polymerized segment A”) are chemically bonded as a crystalline polyester resin. It is preferable to contain a sex polyester resin because the low temperature offset can be improved.
The other polymerization segment A refers to a type of polymerization segment different from the polyester-based polymerization segment. The polymerization segment that can be used for the hybrid crystalline polyester resin is not limited, but is preferably an amorphous polymerization segment. Such a hybrid resin can adjust the affinity with the amorphous resin so that the crystalline resin is uniformly finely dispersed in the amorphous resin.

In the hybrid crystalline polyester resin, a resin portion having a structure derived from a crystalline poeryster resin is referred to as a crystalline polyester polymerized segment, and a resin portion having a structure derived from an amorphous resin is referred to as an amorphous polymerized segment.
Since the hybrid crystalline polyester resin has a high affinity with the amorphous resin in which the amorphous polymerized segment is a matrix phase, the molecular chains of the crystalline polymerized segment can be easily arranged and exhibit sufficient crystallinity. it can.

The content of the crystalline polyester polymerized segment in the hybrid crystalline polyester resin is preferably in the range of 50 to 98% by mass from the viewpoint of imparting sufficient crystallinity to the hybrid crystalline polyester resin.
The components and contents of each segment such as the crystalline polyester polymerized segment in the hybrid crystalline polyester resin can be determined by, for example, NMR analysis, methylation reaction pyrolysis gas chromatography / mass spectrometry (Py-GC / MS: Pyrrolisis Gas Chromatography). It can be measured by Mass Spectrometry) or the like.

The amorphous polymerization segment is not particularly limited as long as it exhibits amorphousness, and examples thereof include an amorphous polyester polymerization segment, an amorphous vinyl polymerization segment, an amorphous urethane polymerization segment, and an amorphous urea polymerization segment. Be done. Above all, when the amorphous polymerized segment has a structure derived from an amorphous resin such as an amorphous polyester resin used as a binder resin, the compatibility with the amorphous resin which is a matrix phase is enhanced. It is possible to obtain charge uniformity and the like.
The content of the other polymerization segment A in the hybrid crystalline polyester resin can be in the range of 40 to 60% by mass, preferably in the range of 45 to 50% by mass.

Examples of the method for synthesizing the hybrid crystalline polyester resin include the following synthesis methods (1) to (3). In the synthesis methods (1) to (3) below, the case where the amorphous polymerization segment is adopted as the other polymerization segment A is described.

(1) After reacting the bireactive monomer with the crystalline polyester resin prepared in advance, the monomer which is the raw material of the amorphous resin is reacted, so that the crystalline polyester polymerized segment is amorphous. Method of Chemically Bonding Polymerized Segments (2) After reacting a bireactive monomer with an amorphous resin prepared in advance, a polyvalent carboxylic acid monomer and a polyhydric alcohol, which are raw materials for the crystalline polyester resin. Method of reacting a monomer to chemically bond a crystalline polyester polymerized segment to an amorphous polymerized segment (3) Reacting a bireactive monomer with a prepared crystalline polyester resin and an amorphous resin And how to chemically bond each as a segment

The bireactive monomer is a monomer that binds a crystalline polyester resin and an amorphous resin, and has a hydroxy group, a carboxy group, an epoxy group, and a first group that can react with the crystalline polyester resin in the molecule. It is a monomer having a substituent such as a secondary amino group and a secondary amino group, and an ethylenically unsaturated group capable of reacting with an amorphous resin. Of these, a vinylcarboxylic acid having a hydroxy group or a carboxy group and an ethylenically unsaturated group is preferable.
As the bireactive monomer, for example, (meth) acrylic acid, fumaric acid, maleic acid and the like can be used, and esters of these hydroxyalkyls (1 to 3 carbon atoms) may be used. From the viewpoint of reactivity, acrylic acid, methacrylic acid or fumaric acid is preferable.

The amount of the bireactive monomer used is 100 parts by mass of the total amount of the monomer used for forming the amorphous polymerized segment from the viewpoint of improving the low temperature fixability, hot offset resistance and durability of the toner. On the other hand, it is preferably in the range of 1 to 10 parts by mass, and more preferably in the range of 4 to 8 parts by mass.

The melting point ( _Tm ) of the crystalline polyester resin is preferably in the range of 55 to 90 ° C., more preferably 70 to 85 ° C. from the viewpoint of obtaining sufficient low temperature fixability and excellent hot offset resistance. is there.
The melting point of the crystalline polyester resin can be controlled by the resin composition.

The melting point ( _Tm ) is the temperature of the peak top of the heat absorption peak and can be measured by DSC.
Specifically, the sample was made of aluminum pan KITNO. It is sealed in B0143013 and set in a sample holder of a thermal analyzer Diamond DSC (manufactured by PerkinElmer), and the temperature is changed in the order of heating, cooling, and heating. The temperature is raised from room temperature (25 ° C.) during the first heating to 150 ° C. at a heating rate of 10 ° C./min from 0 ° C. during the second heating, and kept at 150 ° C. for 5 minutes. The temperature is lowered from 150 ° C. to 0 ° C. at a temperature lowering rate of ° C./min, and the temperature of 0 ° C. is maintained for 5 minutes. The temperature of the peak top of the endothermic peak in the endothermic curve obtained during the second heating is measured as the melting point.

<Amorphous polyester resin>
Examples of the amorphous polyester resin include a condensed polymer of a polyvalent carboxylic acid and a polyhydric alcohol. As the amorphous polyester resin, a commercially available product may be used, or a synthetic resin may be used.
Further, as with the crystalline polyester resin, other binder resins may be contained, and examples thereof include styrene- (meth) acrylic resins and polyester resins, and partially modified modified polyester resins. included.
The styrene- (meth) acrylic resin has a molecular structure of a radical polymer of a compound having a radically polymerizable unsaturated bond, and can be synthesized, for example, by radical polymerization of the compound. The above compound may be one kind or more, and examples thereof include styrene and its derivatives and (meth) acrylic acid and its derivatives.
Examples of the styrene and its derivatives include those similar to crystalline polyester resins.

Examples of the above (meth) acrylic acid and its derivatives include those similar to crystalline polyester resins.

Examples of polyvalent carboxylic acids involved in the synthesis of amorphous polyester resins are aromatic carboxylic acids such as terephthalic acid, isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, naphthalenedicarboxylic acid, and maleine anhydride. Adicyclic carboxylic acids such as acids, fumaric acid, succinic acid, alkenyl anhydride succinic acid and adipic acid; alicyclic carboxylic acids such as cyclohexanedicarboxylic acid; these anhydrides and their lower grades (1 to 5 carbon atoms) Alkyl esters can be mentioned. Among these polyvalent carboxylic acids, aromatic carboxylic acids are desirable.

As the polyvalent carboxylic acid involved in the synthesis of the amorphous polyester resin, a trivalent or higher carboxylic acid having a crosslinked structure or a branched structure (trimellitic acid, its acid anhydride, etc.) is used together with the dicarboxylic acid to ensure fixability. ) May be used together.
These polyvalent carboxylic acids may be used alone or in combination of two or more.

Examples of polyhydric alcohols involved in the synthesis of amorphous polyester resins include aliphatic diols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentylglycol, glycerin, etc .; cyclohexanediol, Alicyclic diols such as cyclohexanedimethanol and hydrogenated bisphenol A; aromatic diols such as ethylene oxide adduct of bisphenol A and propylene oxide adduct of bisphenol A can be mentioned.

Among the polyhydric alcohols involved in the synthesis of these amorphous polyester resins, aromatic diols and alicyclic diols are desirable, and more preferably aromatic diols.
As the polyhydric alcohol involved in the synthesis of the amorphous polyester resin, in order to ensure the fixability, a trihydric or higher polyhydric alcohol (glycerin, trimethylolpropane, pentaerythritol) having a crosslinked structure or a branched structure is used together with the diol. It is good to use it together.
The polyhydric alcohols involved in the synthesis of these amorphous polyester resins may be used alone or in combination of two or more.

(Hybrid amorphous polyester resin)
The amorphous polyester resin contains at least a hybrid amorphous polyester resin in which an amorphous polyester polymerized segment and another polymerized segment (hereinafter, also referred to as “another polymerized segment B”) are chemically bonded. You may be.

In the above hybrid amorphous polyester resin, a resin portion having a structure derived from an amorphous poerystel resin is referred to as an amorphous polyester polymerized segment. The other polymerization segment B refers to a type of polymerization segment different from the polyester-based polymerization segment. The other polymerization segment B that can be used for the hybrid amorphous polyester resin is not particularly limited, but may be, for example, a styrene-acrylic polymerization segment. The styrene-acrylic polymerized segment refers to a molecular chain having the same chemical structure as the resin portion derived from the styrene-acrylic resin, that is, the styrene-acrylic resin, among the hybrid amorphous polyester resins.

The content of the styrene-acrylic polymerized segment in the hybrid amorphous polyester resin is preferably in the range of 1 to 30% by mass because the plasticity of the toner particles can be easily controlled.

The other polymerization segment B is not particularly limited as long as it is a segment derived from a resin other than the amorphous polyester resin. For example, an amorphous vinyl polymerization segment, an amorphous urethane polymerization segment, an amorphous urea polymerization segment, etc. Can be mentioned.

As a method for synthesizing the hybrid amorphous polyester resin, for example, in the synthesis methods (1) to (3) in the hybrid crystalline polyester resin, instead of the crystalline polyester resin or the crystalline polyester polymerized segment, the amorphous polyester resin is amorphous. A polyester resin or an amorphous polyester polymerized segment can be synthesized by using a vinyl polymerized segment as the amorphous polymerized segment.

The weight average molecular weight (Mw) of the hybrid amorphous polyester resin is more preferably in the range of 2000 to 10000 from the viewpoint of fixability.

In addition, the toner matrix particles of the present invention may contain a colorant, a charge control agent, a mold release agent and the like as an internal additive.

Further, the average circularity of the toner matrix particles according to the present invention can be in the range of 0.945 to 0.965.

(Average circularity of toner matrix particles)
The average circularity of the toner matrix particles is a value that can be measured using, for example, "FPIA-2100" (manufactured by Sysmex Corporation). Specifically, the measurement sample (toner) is blended with an aqueous solution containing a surfactant, ultrasonically dispersed for 1 minute to disperse the sample, and then measured under the measurement conditions HPF (high-magnification imaging) according to "FPIA-2100". In the mode, imaging can be performed at an appropriate density of 3000 to 10000 HPF detections, and the circularity of each toner matrix particle can be calculated for each toner matrix particle according to the following formula. The value calculated by adding the circularity of each toner matrix particle and dividing by the total number of toner matrix particles is taken as the average circularity of the toner matrix particles. If the number of HPFs detected is within the above range, reproducibility can be obtained.
Circularity = (peripheral length of a circle having the same projected area as the particle image) / (peripheral length of the particle projected image)

<Colorant>
By further superimposing an existing color toner (for example, the following yellow toner, magenta toner, cyan toner, etc.) on a paper surface on which a metallic luster is produced with the toner of the present invention, an arbitrary color having a metallic luster can be produced. Specifically, for example, by using the toner of the present invention and a toner having a yellow or orange colorant, an image having a golden luster can be formed.
Further, the toner particles themselves according to the present invention may have a structure having a colorant, and by using a toner having such a structure, an arbitrary color having a metallic luster can be produced.

Specific examples of the colorant contained in the yellow toner include, for example, C.I. I. Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, C.I. I. Pigment Yellow 14, 17, 74, 93, 94, 138, 155, 180, 185 and the like. These can be used alone or in combination of two or more. Among these, especially C.I. I. Pigment Yellow 74 is preferred.

The content of the colorant contained in the yellow toner is preferably 1 to 10 parts by mass, and more preferably 2 to 8 parts by mass with respect to 100 parts by mass of the binder resin.

Specific examples of the colorant contained in the magenta toner include C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 122, C.I. I. Pigment Red 5, 48: 1, 53: 1, 57: 1, 122, 139, 144, 149, 166, 177, 178, 222 and the like. These can be used alone or in combination of two or more. Among these, especially C.I. I. Pigment Red 122 is preferred.

The content of the colorant contained in the magenta toner is preferably 1 to 10 parts by mass, and more preferably 2 to 8 parts by mass with respect to 100 parts by mass of the binder resin.

Specific examples of the colorant contained in the cyan toner include, for example, C.I. I. Pigment Blue 15: 3 and the like.

The content of the colorant contained in the cyan toner is preferably 1 to 10 parts by mass, and more preferably 2 to 8 parts by mass with respect to 100 parts by mass of the binder resin.

Specific examples of the colorant contained in the black toner include carbon black, magnetic material, and titanium black. Examples of carbon black include channel black, furnace black, acetylene black, thermal black, and lamp black. Examples of the magnetic material include ferromagnets such as iron, nickel and cobalt, alloys containing these ferromagnets, compounds of ferromagnets such as ferrite and magnetite, and ferromagnets that do not contain ferromagnets but are subjected to ferromagnetism by heat treatment. Examples thereof include the alloys shown. Examples of alloys that exhibit ferromagnetism by heat treatment include Whistler alloys such as manganese-copper-aluminum and manganese-copper-tin, and chromium dioxide.

The content of the colorant contained in the black toner is preferably 1 to 10 parts by mass, and more preferably 2 to 8 parts by mass with respect to 100 parts by mass of the binder resin.

In addition to the binder resin, colorant, and external additive, the toner of the present invention can contain an internal additive such as a charge control agent and a mold release agent, and other external additives, if necessary.

<Charge control agent>
The charge control agent is not particularly limited as long as it is a substance capable of giving positive or negative charge by triboelectric charging, and various known positive charge control agents and negative charge control agents can be used.
The content of the charge control agent is preferably 0.01 to 30 parts by mass, and more preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the binder resin.

<Release agent>
As the release agent, various known waxes can be used.
Examples of the wax include polyolefin waxes such as polyethylene wax and polypropylene wax, branched chain hydrocarbon waxes such as microcrysterin wax, long chain hydrocarbon waxes such as paraffin wax and sazole wax, and dialkyls such as distearyl ketone. Ketone wax, carnauba wax, montan wax, behenate behenate, trimethylpropan tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18-octadecanediol di Examples thereof include ester waxes such as stearate, tristearyl trimellitic acid and distealyl maleate, and amide waxes such as ethylenediamine behenylamide and tristealylamide trimellitic acid.

The content of the release agent is preferably 0.1 to 30 parts by mass, and more preferably 1 to 10 parts by mass with respect to 100 parts by mass of the binder resin.

≪Toner manufacturing method≫
The method for producing the toner for developing an electrostatic charge image of the present invention is not particularly limited as long as it can coat the low melting point metal particles with a binder resin, and is, for example, a seed method, a spray drying method, a dry mixing method, and the like. Examples include a method using a microchannel. With such a method, a toner capable of forming an image having a high specular reflectance can be preferably produced.
In the following method, an internal additive such as a colorant, a charge control agent, or a mold release agent may be added, if necessary.

(Seed method)
In the present invention, the seed method refers to a step of coating the outside of low melting point metal particles with a binder resin in latex.

Specifically, the seed method can be carried out as follows, for example.
A latex prepared by mixing a low melting point metal particle dispersion emulsion, a monomer emulsion which is a raw material of a binder resin, a polymerization initiator (for example, potassium persulfate), and ion-exchanged water is prepared. By heating and stirring this latex, the above-mentioned monomers can be polymerized to produce toner matrix particles containing low melting point metal particles covered with a binder resin. A mold release agent such as wax may be dispersed in the latex.
In the above example, the monomer emulsion which is the raw material of the binder resin is used, but instead, the emulsion, solution or dispersion of the binder resin, the solution or dispersion of the monomer, or the like may be used.

(Spray drying method)
In this method, it is preferable to have a step of coating the outside of the low melting point metal particles with the binding resin while mixing the low melting point metal particles and the binder resin in the gas phase.

Specifically, the spray drying method can be carried out as follows, for example.
Using a fluidized bed coating device, an aqueous solution of resin fine particles containing a prepolymerized binder resin and wax such as behenic behenate can be used as a spray solution on low melting point metal particles, and this can be applied to coat the metal particles. it can.
When spraying the spray liquid, it is preferable to spray the spray liquid while sending compressed air to the spray nozzle together with the spray liquid, and to send air at 25 ° C. into the fluidized layer container.

(Dry mixing method)
Specific examples of the dry mixing method include the following methods.
A mixer including a vertical cylindrical processing tank having a stirring blade, low melting point metal particles, and resin particles composed of a mold release agent and a binder resin are charged and mixed. As a result, a mold release agent, a binder resin and a mixture of low melting point metal particles are obtained. Next, the obtained mixture is put into a stirring granulator, and the stirring blade is rotated while flowing oil into the processing tank. By stirring the treatment tank while heating it, toner matrix particles coated with a binder resin can be obtained.

(Micro flow path (microreactor))
The method for producing the toner of the present invention is a method for producing a toner for static charge image development, which comprises a step of coating the outside of the low melting point metal particles with a binder resin using a microchannel. It is preferable to have.

Hereinafter, a specific example of the method using the microchannel will be described with reference to FIG. Note that FIG. 4 is a schematic view showing an example of the microchannel according to the present invention.

A solution in which the binder resin and wax are dispersed in water is injected into the outer flow paths 601a and 601b of the micro flow path 600. Next, the molten low melting point metal is injected into the central flow path 602 of the micro flow path 600 to form droplets whose surface is coated with a binder resin and wax, and then dried to obtain toner matrix particles. be able to. In FIG. 4, the thick line arrow 603 indicates the water flow.

The microchannels that can be used in the present invention are not particularly limited, and known ones can be used. For example, polysiloxane or polyurethane as described in JP-A-2007-533798 can be used. The formed one can be used.
The polyurethane used in the microchannel can be a radiation or photocurable polyurethane oligomer or resin.
The microchannel can be manufactured using a predetermined protyping method on a substrate (wafer and glass) which is an exposure or compression molding of a UV curable resin. Polysiloxane or polyurethane microchannels can be formed by post-curing by casting followed by condensation or by UV cross-linking.
Suitable substrates are silicon (wafer), glass and plastic (eg, RIM (= reactive injection molding) or ASA (acrylonitrile-styrene-acrylic acid ester) or ASA mixture, ABS, produced by the RRIM (= reinforced RIM) process. It can be made of (acrylonitrile-butadiene-styrene), ABS polycarbonate ABS mixture, polycarbonate (PC) and styrene copolymers such as PC / PBTP (polybutylene terephthalate), PA (polyamide) / ABS and polyurethane).
The surface of the polysiloxane or polyurethane can be modified to improve the adhesion between the polymer and the substrate. Surface modifications can be made with chemicals, plasma, radiation, or light.

≪Developer≫
The toner for developing an electrostatic charge image of the present invention can be used as a magnetic or non-magnetic one-component developer, but may be mixed with carrier particles and used as a two-component developer. When the toner is used as a two-component developer, the carrier particles include magnetic particles made of metals such as iron, ferrite and magnetite, and conventionally known materials such as alloys of these metals with metals such as aluminum and lead. It can be used, and ferrite particles are particularly preferable.

[Carrier particles]
The carrier particles are made of a magnetic material, and the surface of the core material particles made of the magnetic material is coated with a resin (hereinafter, also referred to as "carrier coating resin") to form a resin-coated carrier particle or resin. It can also be composed of resin-dispersed carrier particles or the like in which magnetic fine particles are dispersed. It is preferably composed of resin-coated carrier particles from the viewpoint of controlling the true specific gravity to 4.25 to 5 g / cm ³ and the porosity to 8% or less.
The carrier particles may contain an internal additive such as a resistance modifier, if necessary.

<Core particle>
The core material particles constituting the carrier particles are composed of, for example, metal powder such as iron powder and various ferrites. Of these, ferrite is preferred.
As the ferrite, a ferrite containing a heavy metal such as copper, zinc, nickel and manganese, and a light metal ferrite containing an alkali metal or an alkaline earth metal are preferable.
Ferrite is a compound represented by the formula: (MO) _x (Fe ₂ O ₃ ) _y , and the molar ratio y of Fe ₂ O ₃ constituting the ferrite is preferably 30 to 95 mol%. Ferrite having a composition ratio within the above range has an advantage that it is possible to produce carriers that are less likely to cause carrier adhesion because desired magnetization can be easily obtained. M in the formula is manganese (Mn), magnesium (Mg), strontium (Sr), calcium (Ca), titanium (Ti), copper (Cu), zinc (Zn), nickel (Ni), aluminum (Al). , Silicon (Si), Zirconium (Zr), Bismus (Bi), Cobalt (Co), Lithium (Li) and other metal atoms, which can be used alone or in combination of two or more.

<Resin for carrier coating>
By using a highly hydrophobic alicyclic methacrylate ester as a monomer for obtaining a carrier coating resin, the amount of water adsorbed on the carrier particles is reduced, the environmental difference in chargeability is reduced, and the temperature is particularly high. The decrease in the amount of charge in a humid environment is suppressed. Further, the resin obtained by polymerizing a monomer containing an alicyclic methacrylic acid ester has an appropriate mechanical strength, and the surface of the carrier particles is refreshed by the appropriate film wear as a coating material. ..
The alicyclic methacrylic acid ester preferably has a cycloalkyl group having 5 to 8 carbon atoms, and specific examples thereof include cyclopentyl methacrylate, cyclohexyl methacrylate, cycloheptyl methacrylate, and cyclooctyl methacrylate. .. Among these, cyclohexyl methacrylate is particularly preferable from the viewpoint of mechanical strength and environmental stability of the amount of charge.

<Average film thickness of carrier coating resin>
The average film thickness of the carrier coating resin in the carrier particles is preferably in the range of 0.05 to 4.0 μm, more preferably 0.2, from the viewpoint of achieving both carrier durability and low electrical resistance. It is in the range of ~ 3.0 μm.
When the average film thickness of the carrier coating resin is within the above range, the chargeability and durability can be set in preferable ranges.

<Magnetization of carrier particles>
It is preferable that the saturation magnetization is in the range of 30 to 75 Am ² / kg and the residual magnetization is 5.0 Am / kg or less.
By using the carrier particles having such magnetic characteristics, the carrier particles are prevented from partially agglutinating, and the two-component developer is uniformly dispersed on the surface of the developer transport member, so that the concentration is uniform and uniform. It becomes possible to form a high-definition toner image.

≪Image forming device≫
The toner of the present invention can be suitably used for a general electrophotographic image forming apparatus. Specifically, for example, it can be suitably used for the image forming apparatus 1 described in Japanese Patent Application Laid-Open No. 2014-240923 as shown in FIG. Here, the image forming apparatus 1 shown in FIG. 5 is an intermediate transfer type color image forming apparatus using an electrophotographic process technique. In the image forming apparatus 1, photosensitive drums 413 corresponding to the four colors of CMYK are arranged in series in the traveling direction (vertical direction) of the intermediate transfer belt 421, and each color toner image is sequentially transferred to the intermediate transfer belt 421 in a single procedure. The vertical tandem method is adopted.
That is, the image forming apparatus 1 transfers (primary transfer) each color toner image of Y (yellow), M (magenta), C (cyan), and K (black) formed on the photosensitive drum 413 to the intermediate transfer belt 421. Then, after superimposing the toner images of four colors on the intermediate transfer belt 421, the image is formed by transferring (secondary transfer) to the paper.
As shown in FIG. 5, the image forming apparatus 1 preferably includes an image reading unit 10, an operation display unit 20, an image processing unit 30, an image forming unit 40, a paper conveying unit 50, a fixing unit 60, and a control unit 100. ..

The embodiment to which the present invention can be applied is not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit of the present invention.

For example, the toner of the present invention may contain a material similar to the commonly used known toner parent particles in addition to the above-mentioned materials as long as the effect of the present invention is not hindered. Further, the method for synthesizing or producing such a material is not particularly limited, and a known method can be used.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In the examples, the indication of "parts" or "%" is used, but unless otherwise specified, it indicates "parts by mass" or "% by mass".

[Preparation of low melting point metal particles 1 to 30]
<Preparation of low melting point metal particles 2>
(Preparation of low melting point metal [A])
70 g of gallium and 30 g of tin were weighed, placed in a Teflon (registered trademark) beaker, and stirred with a Teflon (registered trademark) spatula while heating to obtain a low melting point metal [A].

(Preparation of low melting point metal particles 2)
100 g of the low melting point metal [A] melted at 85 ° C. was immersed in 300 mL of a 0.2 mass% sodium lauryl sulfate aqueous solution. This was passed through an emulsified membrane having a pore size of 2.5 μm to obtain a gray suspension. The obtained suspension was purified by centrifugation (6000 rpm, 10 min) to obtain 3.4 μm low melting point metal particles 2.

<Preparation of low melting point metal particles 1, 3 to 22>
(Preparation of low melting point metals [B] to [Q])
In the production of the low melting point metal [A], the low melting point metals [B] to [Q] were produced in the same manner except that the composition was changed to that shown in Table 1.
In Table 1, Ga represents gallium, Sn represents tin, Bi represents bismuth, Pb represents lead, Cd represents cadmium, In represents indium, Zn represents zinc, and Al represents aluminum.
The melting points of the low melting point metals [A] to [Q] are converted based on the phase diagram.

(Preparation of low melting point metal particles 1, 3 to 22)
In the preparation of the low melting point metal particles 2, the low melting point metal species, the melting temperature (simply described as "temperature" in Table 2), the particle size, the pore size, the solvent, and the protective agent are listed in Table 2 and others. Made low melting point metal particles 1, 3 to 22 in the same manner.

<Preparation of low melting point metal particles 23>
A gray suspension was obtained by immersing 1 g of low melting point metal [K] melted at 85 ° C. in 3 mL of a 50 mM tryptophan aqueous solution and irradiating with ultrasonic waves for 3 minutes. The obtained suspension was centrifuged (6000 rpm, 10 min) to obtain 3.4 μm low melting point metal particles 23.

<Preparation of low melting point metal particles 24 to 30>
In the preparation of the low melting point metal particles 23, the same applies except that the low melting point metal species, the melting temperature (simply described as “temperature” in Table 2), the particle size, the solvent, and the protective agent are as shown in Table 2. To prepare low melting point metal particles 24 to 30.

In Table 2, NMP represents N-methylpyrrolidone, SDS represents sodium lauryl sulfate, and DTAB represents lauryltrimethylammonium bromide.

[Preparation of low melting point metal particle dispersions 1 to 30]
<Preparation of low melting point metal particle dispersion emulsion 2>
Ion-exchanged water was added to the low melting point metal particles 2 of 3.4 μm so that the solid content concentration became 20% by mass to prepare a low melting point metal particle dispersion liquid 2. To 500 g of the low melting point metal particle dispersion liquid 2, 2 g of polyoxyethylene-2-dodecyl ether sodium sulfate was added as an emulsifier, and the mechanical disperser "CLEARMIX" (manufactured by M-Technique) having a circulation path was used for 1 hour. The low melting point metal particle dispersion emulsion 2 was prepared by mixing and dispersing.

<Preparation of low melting point metal particle dispersion emulsions 1, 3 to 30>
In the preparation of the low melting point metal particle dispersion emulsion 2, the low melting point metal particle dispersion emulsions 1, 3 to 30 were prepared in the same manner except that the low melting point metal particles 2 were changed to the low melting point metal particles 1, 3 to 30, respectively. did.

[Preparation of binder resin fine particle dispersion 1]
(First stage polymerization)
A 5 L reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introduction device was charged with a solution prepared by dissolving 8 g of sodium dodecyl sulfate in 3 L of ion-exchanged water as an emulsifier, and stirred at a stirring speed of 230 rpm under a nitrogen stream. However, after raising the internal temperature to 80 ° C., a solution prepared by dissolving 10 g of potassium persulfate in 200 g of ion-exchanged water was added as a polymerization initiator to bring the liquid temperature to 80 ° C. again, and 480 g of styrene and n-butyl acrylate. A mixture of 250 g, 68.0 g of methacrylate and 16.0 g of n-octyl-3-mercaptopropionate was added dropwise over 1 hour, and then polymerized by heating and stirring at 80 ° C. for 2 hours to obtain resin fine particles a1. A dispersed resin fine particle dispersion [a1] was prepared.

(Second stage polymerization)
A 5 L reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introduction device is charged with a solution prepared by adding 7 g of sodium polyoxyethylene-2-dodecyl ether sulfate as an emulsifier to 800 mL of ion-exchanged water and heated to 98 ° C. After that, 260 g of the above resin fine particle dispersion solution [a1], 245 g of styrene, 120 g of n-butyl acrylate, 1.5 g of n-octyl-3-mercaptopropionate, 20 g of paraffin wax (melting point 62 ° C.) and microcrystallin wax (melting point 62 ° C.) A monomer solution obtained by dissolving and mixing 180 g of 180 g (melting point 82 ° C.) at 90 ° C. was added, and the mixture was mixed and dispersed for 1 hour by a mechanical disperser "CLEARMIX" (manufactured by M-Technique) having a circulation path to emulsify the monomer. A liquid [a2] was prepared.

[Manufacturing of toner 1]
A solution prepared by dissolving 800 g of a low melting point metal particle dispersion emulsion 2 and 800 g of a monomer emulsion [a2] and 6 g of a polymerization initiator (potassium persulfate) in 200 mL of ion-exchanged water was added, and this system was heated at 82 ° C. for 1 Polymerization was carried out by heating and stirring for a period of time (“shelling time” in Table 3) to produce a toner 1 containing low melting point metal particles 2 covered with a binder resin containing wax. The particle size was 5.1 μm.

[Manufacturing of toners 2 to 24 and 33 to 40]
In the production of the toner 1, the toners 2 to 24, in the same manner, except that the low melting point metal particles, the shelling time, the shell thickness, and the particle size of the toner base particles are as shown in Table 3. 33-40 were manufactured.

(Shell thickness)
Regarding the thickness of the shell, it was confirmed that the core and the shell were held from the projection surface of 20 toners at a magnification of 10000 times, and the size of the core particles in the toner matrix particles, the thickness of the shell, and the release agent The presence was calculated from the results of transmission electron micrographs. The observation magnification was adjusted within the range in which the cross-sectional structure of one toner matrix particle could be known.

Specifically, the thickness of the shell is confirmed by visually observing the core particles from a TEM (transmission electron microscope) photograph of the toner, and the distance from the outermost surface of the toner matrix particles to the core particles is randomly set to 10 points. The measurement was performed, and the thickness of the shell was calculated from the average value. The number of toners for TEM photography was set to at least 20.
The toner matrix particles according to the toners 1 to 40 of this embodiment were all toner matrix particles composed of one core particle (metal particle) and a shell covering the periphery thereof.

[Manufacturing of toner 25]
A styrene acrylic resin (weight average molecular weight) composed of 67 parts by mass of styrene, 28 parts by mass of n-butyl acrylate, and 5 parts by mass of methacrylic acid on low melting point metal particles 2 (600 g) using a fluidized layer coating device having an internal volume of 10 liters. (Mw) 28000, Mw / Mn = 2.25, acid value 32.6 mgKOH / g, glass transition temperature (Tg) 45 ° C.) 95 parts by mass and behenyl behenate (acid value 0.1 mgKOH / g, hydroxy base value 4 mgKOH) / G, melting point 71 ° C.) An aqueous solution of resin fine particles containing 20% of solid content of 5 parts by mass was used as a spray solution, and this was applied and coated.
When spraying the spray liquid, 20 NL / min (20 × 1.079 L / min) of compressed air is sent to the spray nozzle together with the spray liquid to spray the spray liquid at a pace of 3 mL / min and 0.3 m ³ /. Air at 25 ° C. was sent into the fluidized layer container at a min pace (the amount of intake of the fluidized gas per unit time was set to 10000 times the amount of spray liquid sprayed per unit time).
The peripheral speed of the stirring blade was rotated at 5 m / sec, and the gap between the stirring blade and the mesh screen was set to 0.5 mm. The mesh screen used had a thickness of 1 mm, an aperture ratio of 50%, and a hole diameter of 1 mm. After 1.5 hours, the supply of 270 mL of the spray liquid was completed, and a shell containing a resin and wax in the low melting point metal particles 2 was prepared to manufacture the toner 25.

[Manufacturing of toners 26 and 27]
In the production of the toner 25, the toners 26 and 27 were produced in the same manner except that the low melting point metal particles, the thickness of the shell and the particle size of the toner base particles were as shown in Table 3.

[Manufacturing of toner 28]
97 parts by mass of low melting point metal particles 8, 0.15 parts by mass of behenyl behenate, 2 in a mixer (Henshell mixer FM10: manufactured by Nippon Coke Industries Co., Ltd.) including a vertical cylindrical processing tank having stirring blades. .85 parts by mass of styrene 67 parts by mass, n-butyl acrylate 28 parts by mass, methacrylic acid 5 parts by mass styrene acrylic resin particles (weight average molecular weight (Mw) 28000, Mw / Mn = 2.25, acid value 32. 6 mgKOH / g, glass transition temperature (Tg) 45 ° C.) was added, and the mixture was mixed at 40 ° C. and 2400 rpm for 10 minutes to obtain a mixture of the resin and the low melting point metal particles 8. Next, the obtained mixture was put into a stirring granulator (vertical granulator VG-5: manufactured by Paulec Co., Ltd.), and the stirring blade (blade) was rotated at 1000 rpm while flowing oil into the treatment tank. The temperature of the treatment tank was set to 118 ° C., and the mixture was stirred for 40 minutes to produce resin-coated low melting point metal particles 8 (toner 28).

[Manufacturing of toner 29]
In the production of the toner 28, the toner 29 was produced in the same manner except that the low melting point metal particles, the thickness of the shell and the particle size of the toner base particles were as shown in Table 3.

[Manufacturing of toner 30]
Resin-coated low melting point metal fine particles (toner 30) were produced using a polyurethane microchannel 600 (diameter 5 μm) having a shape as shown in FIG. Specifically, a styrene acrylic resin composed of 67 parts by mass of styrene, 28 parts by mass of n-butyl acrylate, and 5 parts by mass of methacrylic acid (weight average molecular weight (Mw) 28000, Mw / Mn = 2.25, acid value 32.6 mgKOH). / G, glass transition temperature (Tg) 45 ° C.), 20 parts by mass and 1 part by mass of behenyl behenate were dispersed in 79 parts by mass of water, and a solution was injected into the outer flow paths 601a and 601b at a flow rate of 2.0 mL / hour. did. The molten low melting point metal A was injected into the central flow path 602 at a flow rate of 0.12 mL / hour. After forming the droplets, the particles were dried to obtain the desired resin-coated low melting point particles, and the toner 30 was produced.
Further, in the toner 30, the number average particle size of the low melting point metal particles contained in the toner base particles was 4.1 μm.

(Manufacturing of micro flow path)
The microchannel was manufactured using a predetermined protyping method on a compression molded substrate. The polyurethane microchannel was formed into the shape as shown in FIG. 4 by casting and subsequent post-curing by condensation. A silicon (wafer) was used as the substrate.

[Manufacturing of toner 31]
In the production of the toner 30, the same applies except that the low melting point metal [A] is changed to the low melting point metal [J] so that the number average particle size of the low melting point metal particles contained in the toner base particles is 3.9 μm. To produce the toner 31.

[Manufacturing of toner 32]
In the production of the toner 30, the same applies except that the low melting point metal [A] is changed to the low melting point metal [E] so that the number average particle size of the low melting point metal particles contained in the toner base particles is 4.8 μm. The toner 32 was manufactured.

≪Evaluation of toners 1 to 40≫
[Production example of developer]
To each of the toners 1 to 40, a ferrite carrier having a volume-based median diameter of 60 μm coated with a silicone resin is added so as to have a toner concentration of 6% by mass, and the developing agents 1 to 40 are mixed. Manufactured.

For the above developers 1 to 40, a commercially available full-color copier "bizhub PRO C6501" (manufactured by Konica Minolta KK) was used as an image forming apparatus, and a solid image was used as a manuscript on a paper having a basis weight of 128 / m ^2. The output was performed, and the toners 1 to 40 were evaluated as follows.

[Evaluation item]
The results of the following evaluation are shown in Table 4.

<Specular reflectance>
The specular reflectance of paper printed with developers 1 to 40 was measured with a microreflectance measuring device (USPM-RU-III manufactured by Olympus Corporation).
The average value of the specular reflectance for light of four wavelengths of 450 nm, 555 nm, 580 nm, and 650 nm was taken as the reflectance.

⊚: Reflectance is 40% or more (best; pass)
◯: 20% or more and less than 40% (good; passed)
×: Less than 20% (defective: rejected)

<Charging characteristics (leakage voltage)>
As an image forming apparatus, in a state of being put into a developer of a commercially available full-color copying machine "bizhub PRO C6501" (manufactured by Konica Minolta Co., Ltd.), after performing idle driving for 1 minute, the developer in the developer was collected. The charge distribution is measured using the charge distribution measuring device "Espart Analyzer Type II" (manufactured by Hosokawa Micron), and the content rate (number%) of the inversely charged toner particles with respect to all the toner particles is calculated from the obtained data. Then, the standard deviation was calculated.
If the content of the back-charged toner particles is 2.0% by number or less and the standard deviation is 2.50 or less, there is no practical problem and it is judged to be acceptable.
Criteria:
◯: Inversely charged toner content ratio 2.0 pieces% or less and standard deviation 2.50 or less (best: pass)
Δ: Content ratio of reversely charged toner is greater than 2.0 pieces% or standard deviation is greater than 2.50 (acceptable: pass)

(Summary)
From the above results, it was shown that when the melting point of the metal is 150 ° C. or higher, it cannot be sufficiently wetted and spread to prepare a reflective surface by heating in the electrophotographic process. It was also shown that when the redox potential is larger than −0.20 V, it is difficult to form an oxide film on the metal surface and the metal film is difficult to wet and spread, so that high reflectance cannot be obtained. When the size of the low melting point metal particles in the toner base particles is 2 μm or less, it is difficult for the low melting point metals in the toner to coalesce with each other at the time of fixing, and as a result, gaps are formed between the low melting point metals, which in turn results in high specular reflectance. It was shown that the image to have could not be obtained.

101 Toner base particles 110 Low melting point metal particles 120 shell 200 Toner base particles 210 Low melting point metal particles 220 shell

Claims (9)

A toner for static charge image development containing at least toner matrix particles composed of low melting point metal particles and a binder resin.
The main component of the outermost shell of the toner matrix particles is the binder resin.
The outermost shell does not contain the low melting point metal particles,
The melting point of the low melting point metal is 150 ° C. or lower.
The particle size of the low melting point metal particles is 2 μm or more.
A toner for static charge image development, wherein the standard redox potential of the low melting point metal calculated from the atomic weight ratio is −0.20 V or less. The first aspect of the present invention is that the low melting point metal contains one kind of metal selected from gallium, tin, zinc, aluminum, bismuth, germanium, silicon and indium, or an alloy composed of a plurality of kinds of metals. The above-mentioned static charge image developing toner. The toner for developing an electrostatic charge image according to claim 1 or 2, wherein the melting point of the low melting point metal is in the range of 50 to 150 ° C. The toner for static charge image development according to any one of claims 1 to 3, wherein the toner matrix particles further contain a release agent or a charge control agent. The toner for developing an electrostatic charge image according to any one of claims 1 to 4, wherein an external additive is added. The invention according to any one of claims 1 to 5, wherein the volume ratio of the low melting point metal to the total volume of the electrostatic charge image developing toner is in the range of 10 to 50 vol%. Toner for static charge image development. A method for producing an electrostatic charge image developing toner according to any one of claims 1 to 6, wherein the electrostatic charge image developing toner is produced.
A method for producing a toner for static charge image development, which comprises a step of coating the outside of the low melting point metal particles with the binder resin in latex. A method for producing an electrostatic charge image developing toner according to any one of claims 1 to 6, wherein the electrostatic charge image developing toner is produced.
A toner for static charge image development, which comprises a step of coating the outside of the low melting point metal particles with the binding resin while mixing the low melting point metal particles and the binding resin in a gas phase. Production method. A method for producing an electrostatic charge image developing toner according to any one of claims 1 to 6, wherein the electrostatic charge image developing toner is produced.
A method for producing a toner for static charge image development, which comprises a step of coating the outside of the low melting point metal particles with the binder resin using a microchannel.

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