JP2013114231A - Toner for electrostatic charge development and two-component developer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner for electrostatic charge development and a two-component developer, in which the toner is excellent in low-temperature fixability and free of aggregation even when stored at high temperature, although glycerin or a glycerin derivative is used, and the toner can be charged into a desired charge amount.SOLUTION: The toner for electrostatic charge image development comprises at least a binder resin, a colorant, a charge control agent, and a release agent. The binder resin is a copolymer between a carboxylic acid component and an alcohol component comprising at least glycerin and/or at least one glycerin derivative selected from the group consisting of 1,2-propanediol, 1,3-propanediol, and monoacylglycerol having 12 to 20 carbon atoms in an acyl group. The charge control agent comprises a nigrosine compound and a quaternary ammonium salt compound.

Description

  The present invention relates to an electrostatic image developing toner and a two-component developer.

  In general, in an image forming method such as electrophotography, the surface of an electrostatic latent image carrier (photoconductor) is charged by corona discharge or the like, and then exposed by a laser or the like to form an electrostatic latent image. The electrostatic latent image is developed with toner to form a toner image, and the toner image is transferred to a recording medium to obtain a high quality image. Usually, the toner used for forming the toner image is mixed with a binder resin such as a thermoplastic resin, a colorant, a charge control agent, a release agent, etc., kneaded, pulverized, and classified to have an average particle diameter of 5 to 10 μm. Toner particles are used. For the purpose of imparting fluidity to the toner, controlling the charge amount of the toner, and improving the cleaning property of the toner remaining on the photoreceptor without being transferred, inorganic fine particles such as silica and titanium oxide are used. Powder or the like is externally added to the toner.

  With respect to such toner, from the viewpoints of energy saving, apparatus miniaturization, and the like, a toner having excellent low-temperature fixability that can be fixed satisfactorily without heating the fixing roller is desired. However, toners with excellent low-temperature fixability often use a binder resin with a low melting point or glass transition point or a release agent with a low melting point, and generally tend to aggregate when stored at high temperatures. There's a problem.

  Various studies have been made in order to solve such problems. For example, a toner using a polyester resin using glycerin, a trivalent polyhydric alcohol as a monomer, as a binder resin has been proposed (patent). Reference 1).

JP 2010-20170 A

  However, the polyester resin using glycerin as a monomer described in Patent Document 1 contains many negatively charged ester bonds in the molecular chain because glycerin is a low molecular weight and polyhydric alcohol. Is a positively chargeable toner, it tends to be difficult to charge to a desired charge amount. For this reason, there is a need for a toner that solves the above-mentioned problems related to chargeability without impairing low-temperature fixability and storage stability at high temperatures.

  The present invention has been made in view of such circumstances, and has excellent low-temperature fixability while utilizing glycerin or a glycerin derivative, and does not aggregate when stored at a high temperature. An object of the present invention is to provide a toner for developing an electrostatic image and a two-component developer that can be charged in an amount.

  The present inventors include at least a binder resin, a colorant, a charge control agent, and a release agent, and the polyester resin as the binder resin is at least glycerin and / or 1,2-propanediol, 1,3. A copolymer of an alcohol component containing at least one glycerin derivative selected from the group consisting of propanediol and monoacylglycerol having an acyl group having 12 to 20 carbon atoms, and a carboxylic acid component; The present inventors have found that a charge control agent can solve the above problems by using a toner for developing an electrostatic image containing a nigrosine compound and a quaternary ammonium salt compound, and have completed the present invention. More specifically, the present invention provides the following.

(1) including at least a binder resin, a colorant, a charge control agent, and a release agent,
The binder resin is at least one selected from the group consisting of at least glycerin and / or 1,2-propanediol, 1,3-propanediol, and monoacylglycerol in which the acyl group has 8 to 20 carbon atoms. It is a polyester resin that is a copolymer of a divalent or trivalent or higher alcohol component containing two or more kinds of glycerin derivatives and a divalent or trivalent or higher carboxylic acid component,
The electrostatic charge image developing toner, wherein the charge control agent includes a nigrosine compound and a quaternary ammonium salt compound.
(2) The static according to (1), wherein a total content of the nigrosine compound and the quaternary ammonium salt compound is 1.5 to 2.5 parts by mass with respect to 100 parts by mass of the binder resin. Toner for charge image development.
(3) The electrostatic image developing toner according to (1) or (2), wherein the content of the quaternary ammonium salt compound is 50 to 400 parts by mass with respect to 100 parts by mass of the nigrosine compound.
(4) The electrostatic image developing toner according to (1) to (3), wherein the alcohol component further contains ethylene glycol.
(5) In the alcohol component, a substance amount ratio A / B between a substance amount (A) of the glycerin and / or glycerin derivative and a substance amount (B) of the ethylene glycol is 15% or less. 4) A toner for developing an electrostatic charge image.
(6) A two-component developer comprising the electrostatic image developing toner according to any one of (1) to (5) and a carrier.

  According to the present invention, while using glycerin or a glycerin derivative, it has excellent low-temperature fixability, does not aggregate when stored at high temperatures, and can charge the toner to a desired charge amount. A toner for developing a charge image and a two-component developer can be provided.

  Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the object of the present invention. In addition, although description may be abbreviate | omitted suitably about the location where description overlaps, the summary of invention is not limited.

  The toner for developing an electrostatic image according to the present invention (hereinafter also simply referred to as toner) includes at least a binder resin, a colorant, a charge control agent, and a release agent, and the polyester resin as the binder resin is at least glycerin. And / or a copolymer of an alcohol component containing a glycerin derivative and a carboxylic acid component, and the charge control agent includes a nigrosine compound and a quaternary ammonium salt compound. The toner of the present invention may contain magnetic powder or the like, if necessary, in the binder resin. The toner of the present invention may have a surface treated with an external additive as desired. Further, the toner of the present invention can be mixed with a desired carrier and used as a two-component developer.

  Hereinafter, production of a binder resin, a colorant, a charge control agent, a release agent, a magnetic powder, an external additive, and an electrostatic charge image developing toner, which are essential or optional components constituting the electrostatic charge image developing toner. The method and the carrier used when the toner of the present invention is used as a two-component developer will be described in order.

[Binder resin]
The toner for developing an electrostatic charge image of the present invention uses a polyester resin as a binder resin. The polyester resin is a copolymer of a divalent or trivalent or higher alcohol component containing at least glycerin and / or a glycerin derivative and a divalent or trivalent or higher carboxylic acid component. Hereinafter, regarding the binder resin, the alcohol component, the carboxylic acid component, and the method for producing the binder resin will be described in order.

(Alcohol component)
In the present invention, the divalent or trivalent or higher alcohol component used as a monomer of the polyester resin used as the binder resin includes at least glycerin and / or a glycerin derivative. Examples of the glycerin derivative include 1,2-propanediol, 1,3-propanediol, and monoacylglycerol. The acyl group in monoacylglycerol is not particularly limited as long as the object of the present invention is not impaired, and may be a saturated acyl group or an unsaturated acyl group. Further, the acyl group in monoacylglycerol may be a linear acyl group or a branched acyl group. The number of carbon atoms of the acyl group in monoacylglycerol is preferably 12-20. More preferred glycerin derivatives include propanediol, and those containing either 1,2-propanediol, 1,3-propanediol, or both are particularly preferred.

  The manufacturing method of glycerol and a glycerol derivative is not specifically limited, A glycerol and a glycerol derivative are manufactured by chemical synthesis, a fermentation method, the combination of these methods, etc. For example, the method of hydrolyzing vegetable fats and oils and purifying glycerol from the obtained reaction product is mentioned. Moreover, the method of obtaining the propanediol as a glycerol derivative by making the obtained glycerol and hydrogen react in presence of a hydrocracking catalyst is mentioned (refer Unexamined-Japanese-Patent No. 2010-111618).

  Moreover, since it is easy to obtain a toner having excellent low-temperature fixability, the alcohol component preferably contains ethylene glycol in addition to glycerin and / or a glycerin derivative. When the alcohol component contains glycerin and / or a glycerin derivative and ethylene glycol, it is preferable that the amount ratio of the two ((glycerin and / or glycerin derivative) / ethylene glycol) is 15% or less. When glycerin and / or a glycerin derivative and ethylene glycol are used in such a ratio, it is particularly easy to obtain a toner with good low-temperature fixability.

  The total content of glycerin, glycerin derivative, and ethylene glycol in the alcohol component is not particularly limited as long as the object of the present invention is not impaired. Typically, 70% by mass or more is preferable, and 90% by mass or more is preferable. More preferred is 100% by mass.

  The alcohol component may contain other divalent or trivalent or higher alcohol components other than glycerin, glycerin derivatives, and ethylene glycol as long as the object of the present invention is not impaired. Specific examples of glycerin, glycerin derivatives, and ethylene glycol other divalent or trivalent or higher alcohol components include diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1, 4-butanediol, neopentyl glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetra Diols such as methylene glycol; bisphenols such as bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A, polyoxypropylenated bisphenol A; sorbitol, 1, 2, 3, 6 Hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, diglycerol, 2-methylpropanetriol, 2- Examples thereof include trivalent or higher alcohols such as methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, and 1,3,5-trihydroxymethylbenzene.

(Carboxylic acid component)
Examples of the divalent or trivalent or higher carboxylic acid component used as the monomer of the polyester resin used as the binder resin include the following. Specific examples of the divalent or trivalent or higher carboxylic acid component include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, Sebacic acid, azelaic acid, malonic acid, or n-butyl succinic acid, n-butenyl succinic acid, isobutyl succinic acid, isobutenyl succinic acid, n-octyl succinic acid, n-octenyl succinic acid, n-dodecyl succinic acid, n-dodecenyl succinic acid Divalent carboxylic acids such as acids, isododecyl succinic acid, isododecenyl succinic acid and the like or alkyl or alkenyl succinic acid; 1,2,4-benzenetricarboxylic acid (trimellitic acid), 1,2,5-benzenetricarboxylic acid Acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalene Tricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,2,4-cyclohexanetricarboxylic acid, And trivalent or higher carboxylic acids such as tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, and empole trimer acid. These divalent or trivalent or higher carboxylic acid components may be used as ester-forming derivatives such as acid halides, acid anhydrides, and lower alkyl esters. Here, “lower alkyl” means an alkyl group having 1 to 6 carbon atoms.

(Binder resin production method)
The method for producing the polyester resin used as the binder resin is not particularly limited, and can be appropriately selected from known polyester resin production methods. As a method for producing a polyester resin, for example, the above-described alcohol component and carboxylic acid component are put in a reaction vessel, and in the presence of a catalyst, a polycondensation reaction is performed at 200 to 250 ° C. while removing by-product volatile components. The method of performing is mentioned. During the polycondensation reaction, the reaction vessel can be depressurized for the purpose of removing volatile components and promoting the polycondensation reaction. Examples of the catalyst include metals such as tin, titanium, antimony, manganese, nickel, zinc, lead, iron, magnesium, calcium, and germanium, and these metal-containing compounds.

  The amount of the alcohol component and the carboxylic acid component used in producing the polyester resin is not particularly limited as long as the object of the present invention is not impaired. The amount of the alcohol component and the carboxylic acid component used is preferably such that the number of moles of the hydroxyl group contained in the alcohol component is typically 4 times or more the number of moles of the carboxyl group contained in the carboxylic acid component, An amount of 4 to 5 times is more preferable. When the number of moles of hydroxyl groups contained in the alcohol component is increased relative to the number of moles of carboxyl groups contained in the carboxylic acid component, the acid value of the resulting toner tends to decrease and the amount of water absorption of the toner tends to increase. For this reason, by adjusting the magnification of the number of moles of hydroxyl groups contained in the alcohol component with respect to the number of moles of carboxyl groups contained in the carboxylic acid component, the acid value and water absorption of the toner obtained can be adjusted.

  When the carboxylic acid component is an acid halide or a lower alkyl ester, the number of moles of the carboxyl group contained in the carboxylic acid component is calculated using the number of moles of the halocarbonyl group or the lower alkoxycarbonyl group as the number of moles of the carboxyl group. . Further, when the carboxylic acid component is an acid anhydride, the number of moles of the carboxyl group contained in the carboxylic acid component is calculated using the number obtained by doubling the number of moles of the acid anhydride group as the number of moles of the carboxyl group.

The toner according to the present invention preferably uses a biomass-derived material as a raw material for the polyester constituting the binder resin from the viewpoint of carbon neutrality. The kind of biomass is not particularly limited, and may be plant biomass or animal biomass.
Among the biomass-derived materials, plant biomass-derived materials are more preferred because they are readily available in large quantities and are inexpensive. Among polyester raw materials, it is preferable to use glycerin and / or glycerin derivatives as biomass-derived materials. Specific examples of methods for producing glycerin and / or glycerin derivatives from biomass include chemical hydrolysis of vegetable oils or animal fats with acids, bases, etc., or biological hydrolysis with enzymes, microorganisms, etc. Is mentioned. Glycerin can also be produced by fermentation from a substrate containing a saccharide such as glucose.

Among the CO ₂ present in the atmosphere, the concentration of CO ₂ containing radioactive carbon ( ¹⁴ C) is kept constant in the atmosphere. On the other hand, a plant takes in CO ₂ containing ¹⁴ C in the atmosphere in the process of photosynthesis, so that the concentration of ¹⁴ C in carbon in its organic component is the same as the concentration of CO ₂ containing ¹⁴ C in the atmosphere. The concentration is 107.5 pMC (percent Modern Carbon). Moreover, since carbon in animals is derived from carbon contained in plants, the concentration of ¹⁴ C in carbon in the organic components of animals is the same as that in plants.

Here, assuming that the concentration of ¹⁴ C contained in the toner is XpMC, the ratio of carbon derived from biomass out of carbon in the toner can be obtained by the following formula (1).
<Formula (1)>
Ratio of carbon derived from biomass (%) = (X / 107.5) × 100 (1)

In addition, as a particularly preferable plastic product from the viewpoint of carbon neutrality, a biomass product (Japan Bioplastics Association certification) is given to a plastic product in which the proportion of carbon derived from biomass in the carbon contained in the product is 25% or more. . Then, when the concentration X of ¹⁴ C in the toner in which the proportion of carbon derived from biomass in the carbon contained in the toner is 25% or more is obtained from the above formula (1), it is 26.9 pMC or more. Accordingly, it is preferable to prepare the polyester so that the concentration of the carbon radioactive carbon isotope ¹⁴ C contained in the toner is 26.9 pMC or more. The concentration of ¹⁴ C in the carbon element of the petrochemical product can be measured according to ASTM-D6866.

  The softening point of the polyester resin is preferably 80 ° C. or higher and 150 ° C. or lower, and more preferably 90 ° C. or higher and 140 ° C. or lower.

[Colorant]
The electrostatic image developing toner contains a black colorant in the binder resin. A suitable colorant added to the toner is not particularly limited as long as it is a black pigment, and specific examples thereof include black pigments such as carbon black, acetylene black, lamp black, and aniline black. Further, in order to adjust the hue, a black pigment and another color pigment may be used in combination.

  The amount of the colorant used is not particularly limited as long as the object of the present invention is not impaired. Specifically, 1-10 mass parts is preferable with respect to 100 mass parts of binder resin, and 3-7 mass parts is more preferable.

(Charge control agent)
The toner for developing an electrostatic charge image of the present invention contains a charge control agent containing a nigrosine compound and a quaternary ammonium salt compound in a binder resin. The purpose of the charge control agent is to improve the charge level of the toner and the charge start-up characteristic that is an indicator of whether or not the toner can be charged to a predetermined charge level in a short time, and to obtain a toner having excellent durability and stability. used.

  When a polyester resin manufactured using glycerin or a glycerin derivative as a monomer is used as the binder resin, it tends to be difficult to charge the toner to a desired charge amount. However, in the toner of the present invention, a toner having excellent chargeability that can be easily charged to a desired charge amount by using a nigrosine compound and a quaternary ammonium salt compound in combination as a charge control agent. Can be prepared.

  The amount of nigrosine-based compound used is not particularly limited as long as the object of the present invention is not impaired, and is preferably 0.3 to 3.0 parts by mass with respect to 100 parts by mass of the binder resin, and 0.5 to 2.0. Part by mass is more preferable. The amount of the quaternary ammonium salt compound used is not particularly limited as long as the object of the present invention is not impaired, and is preferably 0.3 to 3.0 parts by mass with respect to 100 parts by mass of the binder resin, 0.5 to 2.0 parts by mass is more preferable. Further, the total amount of the nigrosine compound and the quaternary ammonium salt compound is preferably 1.5 to 2.5 parts by mass with respect to 100 parts by mass of the binder resin, and 4 to the amount of nigrosine compound used. The amount of the quaternary ammonium salt compound used is preferably 50 to 400 parts by mass, more preferably 100 to 200 parts by mass with respect to 100 parts by mass of the nigrosine compound. Hereinafter, the nigrosine compound and the quaternary ammonium salt compound will be described in order.

(Nigrosine compounds)
The type of nigrosine compound to be contained in the toner is not particularly limited as long as the object of the present invention is not inhibited. For example, nigrosine compounds such as nigrosine, nigrosine salt, nigrosine derivatives, nigrosine BK, nigrosine NB, nigrosine Z and the like. An acidic dye made of a nigrosine compound can be used.

  When synthesizing nigrosine dye, the synthesis method is not particularly limited. Nigrosine dye is prepared by heating an aniline compound such as aniline or aniline hydrochloride and a nitrobenzene compound such as nitrobenzene, nitrophenol, or nitrocresol in the presence of a mixture of hydrochloric acid and iron or iron chloride, iron chloride, or the like. Can be produced by condensation.

(Quaternary ammonium salt compound)
The quaternary ammonium salt compound is not particularly limited as long as it is a compound having a quaternary ammonium salt structure, and may be a low molecular quaternary ammonium salt having one quaternary amino group in the molecule. A charge control resin into which a quaternary ammonium salt functional group has been introduced (hereinafter also referred to as a quaternary ammonium salt functional group-containing resin) may be used.

  The kind of the low-molecular quaternary ammonium salt is not particularly limited as long as the object of the present invention is not impaired, and can be appropriately selected from those conventionally used as a charge control agent for toner. Specific examples of the low-molecular quaternary ammonium salt include benzylmethylhexyldecylammonium and decyltrimethylammonium chloride. Examples of commercially available quaternary ammonium salt compounds include “Bontron P-51” and “Bontron P-52” manufactured by Orient Chemical Industry Co., Ltd.

  Specific examples of the quaternary ammonium salt functional group-containing resin include a styrene resin having a quaternary ammonium salt, an acrylic resin having a quaternary ammonium salt, and a styrene-acrylic resin having a quaternary ammonium salt, and a quaternary ammonium. Examples thereof include a polyester-based resin having a salt.

  The method for producing the quaternary ammonium salt functional group-containing resin is not particularly limited. For example, the resin can be obtained by copolymerizing an addition-polymerizable monomer having a quaternary ammonium salt functional group with a styrene and / or acrylic monomer.

  The addition-polymerizable monomer having a quaternary ammonium salt functional group is derived from a dialkylaminoalkyl (meth) acrylate, dialkyl (meth) acrylamide, or dialkylaminoalkyl (meth) acrylamide through a quaternization step. Monomers are used. Specific examples of the dialkylaminoalkyl (meth) acrylate include dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dipropylaminoethyl (meth) acrylate, dibutylaminoethyl (meth) acrylate and the like. Specific examples of dialkyl (meth) acrylamide include dimethylmethacrylamide, and specific examples of dialkylaminoalkyl (meth) acrylamide include dimethylaminopropylmethacrylamide. Specific examples of the reagent used for the quaternization of the tertiary amino group include alkyl halides having 1 to 6 carbon atoms such as methyl chloride, methyl bromide and ethyl chloride; 1 carbon atom such as dimethyl sulfate and diethyl sulfate. Sulfuric acid ester which is an alkyl ester of -6; Aralkyl halide having 7 to 10 carbon atoms such as benzyl chloride. Two or more kinds of addition-polymerizable monomers having a quaternary ammonium salt functional group can be used.

  Further, the quaternary ammonium salt functional group-containing resin can be used alone, but it can also be used by mixing with a resin other than the quaternary ammonium salt functional group-containing resin. The resin mixed with the quaternary ammonium salt functional group-containing resin is not particularly limited as long as the object of the present invention is not impaired. Specific examples of resins that can be used by mixing with a quaternary ammonium salt functional group-containing resin include polystyrene resins and styrene-acrylic resins.

  When a quaternary ammonium salt functional group-containing resin and a resin other than a quaternary ammonium salt functional group-containing resin are mixed and used, the mixing method is not particularly limited as long as both are uniformly mixed. Specific examples of the mixing method include melt kneading using a single screw extruder or twin screw extruder, and a method of removing the organic solvent after dissolving the resin material to be mixed in the organic solvent.

〔Release agent〕
The toner for developing an electrostatic charge image of the present invention contains a release agent. The release agent is used for the purpose of improving the toner fixing property and offset resistance. The type of release agent added to the toner is not particularly limited as long as the object of the present invention is not impaired. The mold release agent is preferably a wax, and examples of the wax include polyethylene wax, polypropylene wax, fluororesin-based wax, Fischer-Tropsch wax, paraffin wax, ester wax, montan wax, rice wax and the like. These release agents can be used in combination of two or more. By adding such a release agent to the toner, it is possible to more efficiently suppress the occurrence of offset and image smearing (dirt around the image when the image is rubbed).

  The amount of the release agent used is not particularly limited as long as the object of the present invention is not impaired. The amount of the specific release agent used is preferably 1 to 5 parts by mass with respect to 100 parts by mass of the binder resin. If the amount of the release agent used is too small, the desired effect may not be obtained in terms of suppressing the occurrence of offset and image smearing in the formed image. If the amount of release agent used is excessive, In some cases, the storage stability of the toner may be reduced due to the fusing.

[Magnetic powder]
The toner of the present invention can be made into a magnetic toner by blending magnetic powder in a binder resin. The kind of magnetic powder blended in the binder resin is not particularly limited as long as the object of the present invention is not impaired. Examples of suitable magnetic powders include: irons such as ferrite and magnetite; ferromagnetic metals such as cobalt and nickel; alloys containing iron and / or ferromagnetic metals; compounds containing iron and / or ferromagnetic metals; A ferromagnetic alloy subjected to a ferromagnetization treatment such as chromium dioxide.

  The particle size of the magnetic powder is not limited as long as the object of the present invention is not impaired. The particle diameter of the specific magnetic powder is preferably 0.1 to 1.0 μm, and more preferably 0.1 to 0.5 μm. When magnetic powder having a particle diameter in such a range is used, it is easy to uniformly disperse the magnetic powder in the binder resin.

  The magnetic powder can be used that has been surface-treated with a surface treatment agent such as a titanium coupling agent or a silane coupling agent for the purpose of improving dispersibility in the binder resin.

  The usage-amount of magnetic powder is not specifically limited in the range which does not inhibit the objective of this invention. When the toner is used as a one-component developer, the specific amount of the magnetic powder is preferably 20 to 60 parts by mass, more preferably 30 to 50 parts by mass when the total amount of toner is 100 parts by mass. If the amount of magnetic powder used is excessive, the durability of the image density may decrease or the fixability may be extremely reduced. If the amount of magnetic powder used is too small, fogging is likely to occur. In some cases, it is difficult to maintain the image density when printing is performed for a long time. When the toner is used as a two-component developer, the amount of magnetic powder used is preferably 20% by mass or less and more preferably 15% by mass or less when the total amount of toner is 100 parts by mass.

(External additive)
For the purpose of improving the fluidity, storage stability, cleaning properties, etc. of the toner, an external additive may be attached to the surface of the toner.

  The type of external additive is not particularly limited as long as it does not impair the object of the present invention, and can be appropriately selected from external additives conventionally used for toners. Specific examples of suitable external additives include silica and metal oxides such as alumina, titanium oxide, magnesium oxide, zinc oxide, strontium titanate, and barium titanate. These external additives can be used in combination of two or more.

  The particle diameter of the external additive is not particularly limited as long as the object of the present invention is not impaired, and typically 0.01 to 1.0 μm is preferable.

  The volume specific resistance value of the external additive can be adjusted by forming a coating layer made of tin oxide and antimony oxide on the surface of the external additive and changing the thickness of the coating layer and the ratio of tin oxide to antimony oxide. .

  The amount of the external additive used for the toner is not particularly limited as long as the object of the present invention is not impaired. Typically, the amount of the external additive used is preferably 0.1 to 10 parts by mass and more preferably 0.2 to 5 parts by mass with respect to 100 parts by mass of the toner. When the external additive is used in such an amount, it is easy to obtain a toner excellent in fluidity, storage stability, and cleaning properties.

[Method for producing toner for developing electrostatic image]
Hereinafter, a method for producing the toner for developing an electrostatic charge image of the present invention will be described.

  The method for producing the toner for developing an electrostatic charge image according to the present invention is not particularly limited as long as the nigrosine compound and the quaternary ammonium salt can be satisfactorily dispersed in the polyester resin as the binder resin. It can be suitably selected from known toner production methods. As a suitable production method, for example, a binder resin, a nigrosine compound, a quaternary ammonium salt compound, a colorant, a release agent, a magnetic powder, and the like are mixed using a mixer, and then the resulting mixture is obtained. Can be produced by melt-kneading and then crushing and classifying the melt-kneaded product. The melt-kneading apparatus used for the production of the electrostatic image developing toner is not particularly limited, and can be appropriately selected from apparatuses used for melt-kneading thermoplastic resins. Specific examples of the melt-kneading apparatus include a uniaxial or biaxial extruder. The average particle size of the pulverized and classified toner is not particularly limited as long as the object of the present invention is not impaired, but generally 5 to 10 μm is preferable.

  The surface of the toner thus obtained may be treated with an external additive as necessary. The method for treating the toner with the external additive is not particularly limited, and can be appropriately selected from conventionally known methods for treating the external additive. Specifically, the processing conditions are adjusted so that the particles of the external additive are not embedded in the toner base particles, and the processing with the external additive is performed by a mixer such as a Henschel mixer or a Nauter mixer.

[Carrier]
The toner of the present invention can be mixed with a desired carrier and used as a two-component developer. When preparing a two-component developer, it is preferable to use a magnetic carrier. Hereinafter, the carrier core constituting the carrier and the coating agent will be described in order.

  Examples of the carrier contained in the two-component developer of the present invention include those in which a carrier core is coated with a coating agent. Hereinafter, the carrier core constituting the carrier and the coating agent will be described in order.

(Career core)
The type of carrier core is not particularly limited as long as it is a carrier core conventionally used for carriers for two-component developers. Specific examples of the carrier core include particles of iron, oxidized iron, reduced iron, magnetite, copper, silicon steel, ferrite, nickel, cobalt, etc., and particles of alloys of these materials with manganese, zinc, aluminum, etc., Particles such as iron-nickel alloy, iron-cobalt alloy, titanium oxide, aluminum oxide, copper oxide, magnesium oxide, lead oxide, zirconium oxide, silicon carbide, magnesium titanate, barium titanate, lithium titanate, lead titanate, Ceramic particles such as lead zirconate and lithium niobate, particles of high dielectric constant materials such as ammonium dihydrogen phosphate, potassium dihydrogen phosphate and Rochelle salt, resin carriers in which the above magnetic particles are dispersed in a resin, etc. Can be mentioned.

(Coating agent)
The coating agent for coating the carrier core is not particularly limited as long as it is a coating agent conventionally used for a carrier coating agent for a two-component developer. Specific examples of the coating agent for coating the carrier include (meth) acrylic polymer, styrene polymer, styrene- (meth) acrylic copolymer, olefin polymer (polyethylene, chlorinated polyethylene, polypropylene, etc.) , Polyvinyl chloride, polyvinyl acetate, polycarbonate, cellulose resin, polyester resin, unsaturated polyester resin, polyamide resin, polyimide resin, polyamideimide resin, polyurethane resin, epoxy resin, silicone resin, fluorine resin, phenol resin, xylene resin, Examples include diallyl phthalate resin, polyacetal resin, amino resin, and aromatic polyether ketone resin. These resins can be used in combination of two or more. As the coating agent for coating the carrier core, a coating agent containing at least one polyamide / imide resin selected from the group consisting of polyamide resin, polyimide resin, and polyamideimide resin and a fluororesin is particularly preferable.

(Carrier manufacturing method)
The carrier contained in the two-component developer of the present invention is produced by coating the carrier core with the coating agent, and then heat-treating the carrier core coated with the coating agent to fix the coating agent to the surface of the carrier core. . 0.1-15 mass% is preferable with respect to the mass of a carrier core, and, as for the usage-amount of the coating agent at the time of manufacturing a carrier, 1-7 mass% is more preferable.

  The method for coating the carrier core with the coating agent is not particularly limited, and is appropriately selected from methods conventionally used for producing carriers. The method of coating the carrier core with the coating agent may be a wet method in which the solvent is removed after the solution of the coating agent is sprayed onto the carrier core, or a dry method in which the powder of the coating agent is attached to the surface of the carrier core. Either may be sufficient. Since the operation is simple and it can be applied to a resin that is hardly soluble in an organic solvent, the carrier core is more preferably coated by a dry method. The method for coating the carrier core with the powder of the coating agent is not particularly limited, and examples thereof include a method using a dry coating apparatus such as Nobilta (registered trademark) (manufactured by Hosokawa Micron Corporation).

  By the above method, the carrier core is coated with the coating agent powder by the dry method, and then the carrier core coated with the coating agent powder is heat-treated to obtain a carrier. Although the temperature of heat processing changes with kinds of resin contained in a coating agent, it is typically performed at 250-320 degreeC. The time for heating the carrier core is not particularly limited, and is typically 30 minutes to 2 hours. By such heat treatment, the coating agent is softened and melted and fixed to the surface of the carrier core.

  The particle diameter of the carrier is not particularly limited as long as the object of the present invention is not impaired, but is preferably 20 to 200 μm, more preferably 30 to 150 μm, as measured by an electron microscope.

The apparent density of the carrier is not particularly limited as long as the object of the present invention is not impaired. The apparent density varies depending on the carrier composition and surface structure, but typically 2400 to 3000 kg / m ³ is preferable.

(Method for producing two-component developer)
The production method of the two-component developer is not particularly limited as long as the toner and the carrier can be uniformly mixed. For example, the toner and the carrier may be mixed by a mixing device such as a ball mill. The content of the toner in the two-component developer is preferably 2 to 20% by mass and more preferably 4 to 15% by mass with respect to the mass of the two-component developer. By setting the toner content in the two-component developer within such a range, an appropriate image density is maintained in the formed image, and the toner scattering from the developing device or the like is suppressed to prevent contamination inside the image forming device or transfer paper. Toner adhesion can be suppressed.

  The electrostatic image developing toner of the present invention described above has excellent low-temperature fixability while utilizing glycerin or glycerin induction, and does not aggregate when stored at a high temperature. Can be charged to an amount. For this reason, the electrostatic image developing toner of the present invention and the two-component developer using the same are suitably used in various image forming apparatuses.

  Hereinafter, the present invention will be described more specifically with reference to examples. In addition, this invention is not limited at all by the Example.

The following propanediol was used as the glycerin derivative used as the polyester monomer.
1,3-propanediol: Sasterapropanediol (plant-derived, manufactured by DuPont).
1,2-propanediol: 1,2-propanediol obtained in the following synthesis example.

[Synthesis Example 1]
(Production of 1,2-propanediol)
Glycerol was obtained by hydrolyzing vegetable fats and oils. Specifically, the vegetable oil was completely saponified under heating by adding 10% aqueous sodium hydroxide solution twice the amount necessary to completely saponify the vegetable oil. After separating the aqueous solution of glycerin from the reaction solution after saponification, the aqueous solution of glycerin was purified by distillation. Distilled glycerin was treated with activated carbon to obtain purified glycerin.

Propanediol was produced as a glycerin derivative from glycerin obtained by the above method.
First, ethylene glycol (200 g) and cupric nitrate trihydrate (76 g) were added to a reactor having a reflux condenser, and after stirring with heating at 80 ° C. for 2 hours, tetraethoxysilane (52 g) was added dropwise. The mixture was stirred with heating at ° C for 2 hours. Thereafter, water (18 g) was added dropwise, and the mixture was heated and stirred at 80 ° C. for 3 hours to obtain a precipitate. The produced precipitate was dried at about 120 ° C. and calcined in air at 400 ° C. for 2 hours to obtain a copper / silica catalyst (copper content 50%). An aqueous solution of tetraammineplatinum (II) nitrate [Pt (NH3) 4 (NO3) 2] (29.8 mg) was added to the obtained copper / silica catalyst (3 g), and dried and dried on a rotary evaporator. The obtained solid was dried at 120 ° C., calcined in air at 400 ° C. for 2 hours, and copper-platinum / silica catalyst (Cu / Pt / Si = 50 / 0.5 / 17) (copper content 50% )
Next, 2 g of a copper-platinum / silica catalyst and 200 g of glycerin were added to a 500 mL iron autoclave equipped with a stirrer and replaced with hydrogen. Thereafter, hydrogen was introduced into an autoclave at 230 ° C. at 5 L / min (25 ° C., H ₂ ), and reacted at a pressure of 2 MPa for 7 hours to obtain a reaction solution. 1,2-propanediol was obtained from the resulting reaction solution by a conventional purification method.

[Synthesis Example 2]
(Synthesis of polyester resin A)
72.20 parts by mass of propanediol (average molecular weight 76) obtained in Synthesis Example 1, 3.10 parts by mass of ethylene glycol, 11.60 parts by mass of terephthalic acid, 104.40 parts by mass of fumaric acid, and 3.mellitic anhydride 3. 84 parts by mass and 1 part by mass of dibutyltin oxide and 0.3 part by mass of hydroquinone as a condensation catalyst were charged in a reaction vessel and reacted for 5 hours while removing water at 200 ° C. under normal pressure to obtain polyester resin A.

(Synthesis of polyester resin B)
A polyester resin B was synthesized in the same manner as the polyester resin A except that the types and amounts of the alcohol component and the carboxylic acid component were changed to the types and amounts shown in Table 1.

[Example 1]
(Toner preparation)
100 parts by mass of polyester resin A as a binder resin, 4 parts by mass of carbon black (MA-100 (Sanyo Dye)), 1 part by mass of nigrosine compound (N-01 (manufactured by Orient Chemical Co., Ltd.)), 4 1 part by mass of a quaternary ammonium salt compound (N-51 (manufactured by Orient Chemical Co., Ltd.)) and 5 parts by mass of a wax (mold release agent, WEP-3 (manufactured by NOF Corporation)) were added to a Henschel mixer (20B (Japan). Coke Co., Ltd.)).
The obtained mixture was melt-kneaded using a twin screw extruder (PCM-30 (manufactured by Ikegai Co., Ltd.)) under the conditions of a material supply speed of 6 kg / hr, a shaft rotation speed of 160 rpm, and a cylinder temperature of 120 ° C., and then cooled. Thus, a kneaded product was obtained. The obtained kneaded material is roughly pulverized with a pulverizer (Rotoplex 16/8 type (manufactured by Toa Machinery Co., Ltd.)) and then finely pulverized with a pulverizer (Turbo Mill RS (manufactured by Turbo Industry Co., Ltd.)). The finely pulverized product was classified with an elbow jet (EJ-LABO model EJ-L-3 (manufactured by Nippon Steel Mining Co., Ltd.)) to obtain toner base particles having a volume average particle diameter of 8 μm.

(External processing)
To 100 parts by mass of the obtained toner base particles, 1.0 part by mass of hydrophobic silica fine particles (RA-200H (manufactured by Nippon Aerosil Co., Ltd.)) is added as an external additive, and a Henschel mixer (10C (Nippon Coke Co., Ltd.) is added. Manufactured by the company) and mixed for 2 minutes at a rotation speed of 3000 rpm and a jacket control temperature of 20 ° C. to obtain an externally added toner.

(Preparation of two-component developer)
A carrier used for a developer for a multifunction machine (TASKalfa-550i (manufactured by Kyocera Mita Co., Ltd.)) and a toner of 10% by mass with respect to the mass of the carrier are mixed with a ball mill for 30 minutes to obtain a two-component developer. Prepared.

  The obtained two-component developer is filled in a black developer of a multi-function machine (TASKalfa-550i (manufactured by Kyocera Mita Co., Ltd.)), and the obtained toner is filled in a black toner container. The image density, fog density, charge amount, toner scattering state, and low-temperature fixability were evaluated. Further, using the toner of Example 1, the heat resistant storage stability and the radioactive carbon concentration were evaluated according to the following methods. Table 3 shows the evaluation results of image density, fog density, charge amount, and toner scattering state. Table 4 shows the evaluation results of the low-temperature fixability and heat-resistant storage stability. The radioactive carbon concentration is shown in Table 5.

<Image density>
An initial image for evaluation was printed, and the image density of the initial image was measured with a reflection densitometer (RD914 (manufactured by Gretag Macbeth)). Next, after 100,000 sheets were continuously printed at a printing rate of 5%, an evaluation image was printed and the image density was measured in the same manner as the initial image. An image density of 1.4 or more was judged as ◯, 1.3 or more and less than 1.4 as Δ, and less than 1.3 as x.

<Fog density>
The reflection density of the non-printed portion of the evaluation image used for measuring the image density was measured with a reflection densitometer (RD914 (manufactured by Gretag Macbeth)). Further, the reflection density of the recording paper before printing was measured. The difference between the reflection density of the printed portion of the evaluation image and the reflection density of the recording paper before printing was defined as the fog density. A fog density of 0.003 or less was evaluated as ◎, a value of 0.003 or more and 0.007 or less was evaluated as ○, and a value exceeding 0.007 was determined as ×.

<Charge amount>
An initial image for evaluation was printed, and the charge amount of the toner at the time of initial image formation was measured by sucking the toner on the developing sleeve using a suction type small charge amount measuring device (manufactured by TReK). Next, 100,000 sheets were continuously printed at a printing rate of 5%. The toner charge amount after 100,000 sheets of continuous printing was measured in the same manner as the initial charge amount.

<Toner scattering>
The toner (scattered toner) accumulated in the tray installed at the bottom of the developing unit after continuous printing of 100,000 sheets was collected, and the amount (scattered amount) was measured. The scattering amount of 50 mg or less was evaluated as “◯”, the amount exceeding 50 mg was evaluated as “Δ”, and the amount exceeding 200 mg was evaluated as “x”.

<Low temperature fixability>
A solid image having an image density of 1.3 or more was rubbed with a 500 g weight covered with a cloth so that only the weight of the weight was applied to the image, and the image density after the friction was measured. The image density was measured using Gretag Macbeth Spectroeye (manufactured by Gretag Macbeth). According to the following formula, the fixing rate was calculated from the image density before and after friction.
Fixing rate (%) = (image density after friction / image density before friction) × 100

  In the above friction test, a fixing rate of 90% or more was obtained, and the lowest temperature at which no cold offset occurred was defined as the minimum fixing temperature. In the friction test, a fixing rate of 90% or more was obtained, and the highest temperature at which hot offset did not occur was defined as the upper limit fixing temperature.

<Heat resistant storage stability>
3 g of the toner of Example 1 was stored at 58 ° C. for 3 hours, and then cooled to room temperature. The cooled toner was sieved by a powder tester (manufactured by Hosokawa Micron Corporation) using a 330 mesh sieve on a vibration scale 5. In the evaluation of heat-resistant storage stability, a pass rate of 90% by mass or more was evaluated as “◎”, 80% or more and less than 90% as “◯”, 70% or more and less than 80% as “Δ”, and less than 70% as “X”.

<Radiocarbon concentration measurement>
The concentration of ¹⁴ C contained in the toner of Example 1 was measured according to ASTM-D6866.

[Example 2]
A toner was obtained in the same manner as in Example 1 except that the polyester resin A was changed to the polyester resin B. For the obtained toner, a two-component developer was prepared in the same manner as in Example 1. Table 3 shows the evaluation results of image density, fog density, charge amount, and toner scattering state. Table 4 shows the evaluation results of the low-temperature fixability and the heat-resistant storage stability. The radioactive carbon concentration is shown in Table 5.

[Examples 3 to 6]
A toner was obtained in the same manner as in Example 1 except that the amount of nigrosine compound to be added and the amount of the quaternary ammonium salt compound were changed to those shown in Table 2. For the obtained toner, a two-component developer was prepared in the same manner as in Example 1. Table 3 shows the evaluation results of image density, fog density, charge amount, and toner scattering state.

[Comparative Example 1]
A toner was obtained in the same manner as in Example 1 except that no quaternary ammonium salt compound charge control agent was added. For the obtained toner, a two-component developer was prepared in the same manner as in Example 1. Table 3 shows the evaluation results of image density, fog density, charge amount, and toner scattering state.

[Comparative Example 2]
A toner was obtained in the same manner as in Example 1 except that the charge control agent for the nigrosine compound to be added was changed to 2 parts by mass and the charge control agent for the quaternary ammonium salt compound was not added. Table 3 shows the evaluation results of image density, fog density, charge amount, and toner scattering state.

[Comparative Example 3]
A toner was obtained in the same manner as in Example 1 except that the charge control agent of the nigrosine compound was not added. Table 3 shows the evaluation results of image density, fog density, charge amount, and toner scattering state.

[Comparative Example 4]
A toner was obtained in the same manner as in Example 1 except that the charge control agent of the quaternary ammonium salt compound to be added was changed to 2 parts by mass and the charge control agent of the nigrosine compound was not added. Table 3 shows the evaluation results of image density, fog density, charge amount, and toner scattering state.

  A toner using a polyester resin using a glycerin having a relatively low molecular weight or a glycerin derivative as a monomer as a binder resin tends to be difficult to be charged to a desired charge amount. However, since the toners of Examples 1 to 6 contain a nigrosine compound and a quaternary ammonium salt compound, while using glycerin or a glycerin derivative, the toner is excellent in low-temperature fixability and is 100,000. Stable charging was obtained even after continuous printing of sheets. As described above, according to the toners of Examples 1 to 6, since the toner can be charged to a desired charge amount, an image having a good image density can be formed, and fog is hardly generated. Further, according to the toners of Examples 1 to 6, it was possible to form an image with a good image density even after continuous printing of 100,000 sheets, and to suppress fogging and toner scattering.

  In Comparative Examples 1 to 4, although the nigrosine compound or the quaternary ammonium salt compound is included in the toner as the charge control agent, only one charge control agent is included. For this reason, the toners of Comparative Examples 1 to 4 cannot be charged to a desired charge amount. Further, after 100,000 sheets were continuously printed, fogging and toner scattering occurred. In particular, the toners of Comparative Examples 3 and 4 have a remarkably reduced charge amount after 100,000 sheets of continuous printing, which makes it difficult to form an image with a good image density.

Claims (6)

Including at least a binder resin, a colorant, a charge control agent, and a release agent,
The binder resin is at least one selected from the group consisting of at least glycerin and / or 1,2-propanediol, 1,3-propanediol, and monoacylglycerol in which the acyl group has 12 to 20 carbon atoms. It is a polyester resin that is a copolymer of a divalent or trivalent or higher alcohol component containing two or more kinds of glycerin derivatives and a divalent or trivalent or higher carboxylic acid component,
The electrostatic charge image developing toner, wherein the charge control agent includes a nigrosine compound and a quaternary ammonium salt compound.   2. The electrostatic charge image development according to claim 1, wherein the total content of the nigrosine compound and the quaternary ammonium salt compound is 1.5 to 2.5 parts by mass with respect to 100 parts by mass of the binder resin. Toner.   The toner for developing an electrostatic charge image according to claim 1, wherein a content of the quaternary ammonium salt compound is 50 to 400 parts by mass with respect to 100 parts by mass of the nigrosine compound.   The electrostatic image developing toner according to claim 1, wherein the alcohol component further contains ethylene glycol.   The said alcohol component WHEREIN: The substance amount ratio A / B of the substance amount (A) of the said glycerol and / or glycerol derivative and the substance amount (B) of the said ethylene glycol is 15% or less. Toner for developing electrostatic images.   A two-component developer comprising the electrostatic image developing toner according to claim 1 and a carrier.