JP3287400B2 - Method for producing negatively chargeable developer composition - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a negatively chargeable developer composition. More specifically, the present invention relates to a negatively chargeable developer composition for visualizing an electric latent image and an electric signal in electrophotography, electrostatic recording, and the like, and in particular, a negatively chargeable developer having excellent chargeability, developability and transferability. The present invention relates to a method for producing a composition. 2. Description of the Related Art As a method for applying a charge to a developer (toner) for visualizing an electric latent image or an electric signal, there are a friction contact charging method, an ion irradiation method, and electrostatic induction using conductivity. Although various methods such as a charge injection method and a charge injection method are known, a friction contact charging method is most easily used and widely used. In the friction contact charging method, in addition to a two-component developer in which toner particles are mixed with carrier particles charged in a polarity opposite to that of the toner in order to impart a charge to the toner, a charging member such as a charging blade or a charging roll is used. Also known are one-component developers that utilize frictional charging of toner or that utilize frictional charging between toners. When the toner is charged by the contact charging or friction charging method, an electron donating substance or an electron withdrawing substance is added to the toner or a charge providing material such as a carrier or a blade to charge the toner. Control. The triboelectric charging phenomenon is complicated and its mechanism is not always clear, but generally, the electron donating substance is positively charged and the electron withdrawing substance is negatively charged. Conventionally, in order to control the charge of the toner,
(I) A dye / pigment, a surfactant, an inorganic powder, etc. are added and mixed in the toner or on the toner particle surface. (Ii) As a binder resin, halogen such as -COOH, -CN, -Cl, -N
Although measures such as using a resinous material having a functional group such as O ₂ and —NH ₂ have been taken, control over time stability of toner chargeability and environmental stability has not been successful, It was not satisfactory. In addition, there was no colorless or light-colored good charge control agent usable for color development. SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a quick charge rise, easy control of the charge amount and charge distribution, excellent environmental stability of chargeability, stability over time, and developability. Another object of the present invention is to provide a method for producing a developer composition in which transferability is improved and good image quality is guaranteed. It is still another object of the present invention to provide a method for producing a color developer composition in which charging rises quickly and the control of the charge amount and charge distribution is easy. The present inventors have made intensive studies and as a result, have found that an organic anionic component (A) containing boron is contained.
And an organic boron compound (AD) comprising a cationic component (D) having a smaller molecular size than the organic anionic component (A) as a charge exchange control agent of a developer,
Average charge amount of toner by blow-off tribo method is -1
The inventors have found that the above problems can be improved and overcome by adding a charge exchange controlling agent so as to be 2 μc / g or more, and have completed the present invention. In this specification, "-1
“2 μc / g or more” means that the absolute value of the average charge amount is 12 μc / g.
g or more, which means that the sign is negative. That is, the present invention provides an organic boron compound (AD) comprising an organic anionic component containing boron (A) and a cationic component (D) having a smaller molecular size than the organic anionic component (A). A method for producing a negatively chargeable developer composition comprising a negatively chargeable charge exchange control agent, characterized by comprising: Here, the molecular size is represented by, for example, a Stokes radius. The organic boron compound (A) used in the present invention
The boron-containing organic anionic component (A) of D) has the general formula: Indicated by In the formula, R ₁ , R ₂ , R ₃ and R ₄ are mutually independent organic groups, which may be the same, and R ₁ and R ₂ and R ₃ and R ₄ A ring may be formed together with boron (B) to which each is bonded. Examples of such a boron-containing organic anionic component (A) include the following. Embedded image In the formula, R represents an organic group. On the other hand, the cationic component (D) includes H ⁺ and alkali metal cations such as Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , Cu ⁺ , Ag ⁺ , Be ²⁺ , Mg ^2+. , Ca ²⁺ , S
alkaline earth metal cations such as r ²⁺ , Ba ²⁺ , C
It can be selected from d ²⁺ , Zn ^{2+ and} other polyvalent metal cations, organic amine cations such as pyridinium, quinolinium and imidazolinium, sulfonium cations, and phosphonium cations. These boron-containing organic anionic components (A)
It is not always clear why the organoboron compound (AD) having a neutralized salt structure of the compound and the cationic component (D) has excellent charge exchange controllability.
(I) the electron accepting property of boron, (ii) the structure of a neutralized salt type,
(Iii) It is presumed that the effect of the organic functional group promotes exchange and transfer of electrons and / or ions in the compound itself and in a composite material in which the compound is dispersed or dissolved in a polymer or the like. Further, the above general formula: When the organic functional group has one or more, preferably two or more aromatic rings such as a benzene ring and a naphthalene ring in the organic functional group, the boron-containing organic anionic component (A) has a large effect of improving the charge exchange property. . In the present invention, as described above, a boron-containing organic anion component utilizing the electron-accepting property of boron is used for the negatively charged charge exchange controlling agent and the negatively charged developer composition, and the organic anionic component ( A) An organic boron compound (AD) having a smaller molecular size than that of A) is used as a charge exchange control agent, and charged so that an average charge amount by a blow-off tribo method is -12 μc / g or more, and a developer composition is prepared. I do. Therefore, it can be effectively used mainly for controlling the negative charge property and promoting the charge exchange of the negative charge material. However, depending on the method of use, a compound represented by AD can be added to the positively chargeable material to further improve the charge exchange property or to control the conductivity of the material. The charge polarity of the organic boron compound (AD) is considered to be determined by the composition or molecular size of the organic anionic component A and the cationic component D forming the compound (AD). Depending on the composition of (D), or when the molecular size of (D) is large, both are neutral salt type compounds (A
D) tends to exhibit positive charge controllability rather than negative charge controllability. In such a case, the characteristics of the compound are determined by the component (D) rather than the component (A). However, in the present invention, the component (D) contains boron as the component (A) as described above. By using a cationic component having a smaller molecular size than an anionic component, a negative charge control property is exhibited. In the present invention, the organic boron compound contained in the developer composition is often colorless or pale.
Moreover, since it is excellent in charge controllability, it can be used very favorably for charge control of materials which are difficult to color, such as color developers, in addition to black developers. As the organoboron compound used in the present invention, it is desirable to use a solid substance at ordinary temperature having a melting point or softening point of about 50 ° C. or higher. However, a liquid substance can be used depending on the method of use, such as when only the surface layer of the developer is treated. Further, the liquid material is carried or impregnated with inorganic fine powder, resin fine powder, porous material, gelling agent, etc.,
It can be used after apparently solidifying. When the organic boron compound is used for charge exchange control for controlling the charge of the developer of the present invention, about 0.01% to about 10% by weight, preferably about 0.1% to about 5% by weight in the developer. By adding by weight, the electrical properties of the developer can be improved very well. The method of adding to the developer may be not only dispersing or dissolving in the developer, but also selectively adding only to the surface layer of the developer or adding and mixing outside the developer.
When added to and mixed with the developer, in addition to being mechanically mixed with the binder resin by a method such as melt mixing, emulsion mixing, and solution mixing, the binder resin is polymerized in the presence of the organic boron compound of the present invention to form a binder. The organoboron compound of the present invention may be mixed or dissolved in the resin. In this case, a chemical bond may be formed between the organic boron compound of the present invention and a binder resin or another additive in a developer. As the binder resin of the developer composition, conventionally known binder resins can be used. For example, styrenes such as styrene, chlorostyrene and vinyl styrene; monoolefins such as ethylene, propylene, butylene and isobutylene; vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate and vinyl butyrate; methyl acrylate and ethyl acrylate , Butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate,
Esters of α-methylene aliphatic monocarboxylic acids such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate; vinyl methyl ether;
Vinyl ethers such as vinyl ethyl ether and vinyl butyl ether; homopolymers and copolymers such as vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and vinyl isopropenyl ketone can be exemplified. Particularly typical binder resins are , Polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyethylene, and polypropylene. Can be. Further, polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, paraffin and wax can be mentioned. Examples of the coloring agent include black dyes and pigments such as carbon black, oil black, and graphite; CI. Pigment Yellow 1, 3, 3, 74,
97, 98 etc. acetoacetic acid arylamide type monoazo yellow pigments (fast yellow type); CI Pigment Yellow
12, 33, and 14 acetoacetic acid arylamide-based disazo yellow pigments; CI Solvent Yellow 19, 77,
79, CI Disperse Yellow 164 and other yellow dyes;
I. Pigment Red 48, 49: 1, 53: 1, 5
7: 1, 81, 122, 5 and the like red or red pigment; CI Solvent Red 52, 58 and 8 and the like red dye; CI Pigment Blue 15: 3 and the like copper phthalocyanine and its derivatives, modified products, etc. Conventionally, dyes and pigments known for printing inks and other coloring applications such as blue dyes and pigments, and colored or colorless sublimable dyes can be used. These dyes and pigments may be used alone or in combination of two or more. Of course, the color tone may be adjusted by mixing with an extender or a white pigment. Furthermore, in order to improve the dispersibility of the binder component, the surface of the coloring agent is treated with a surfactant, a coupling agent such as a silane coupling agent, a polymer material, or a polymer dye or a polymer graft pigment. May be used. The binder resin and the colorant are not limited to those exemplified above. Further, the developer composition obtained by the present invention comprises:
A magnetic material (for example, ferrite or the like) can be included and used as a magnetic toner. In addition, in the present invention, in the developer composition, a conventionally known charge control agent can be used in combination as another additive, and a conductivity adjusting agent, an inorganic substance such as a metal oxide, a reinforcing filler, and an antioxidant. Agents and the like can also be used. Further, as external additives, silica, carbon,
Conventionally known materials such as alumina, titanium oxide, zinc oxide, fine resin powder, tin oxide, higher fatty acids and derivatives thereof such as metal salts can be used. The developer composition can be produced by any method such as a kneading and pulverizing method, a spray drying method, and a direct polymerization method. The particle size of the developer composition, the average particle size d ₅₀ measured by a Coulter counter method is 1 to 20 [mu] m, preferably 5 to
Those having a size of about 15 μm are preferable. The developer composition according to the present invention can be used as a so-called two-component developer using a carrier and a toner, or as a so-called one-component developer without using a carrier. The present invention provides an organic boron compound (AD) comprising a boron-containing organic anionic component and a cationic component (D) having a smaller molecular size than the organic anionic component (A). A negatively chargeable developer composition containing a negatively chargeable charge exchange controlling agent comprising the negative chargeable developer composition according to the production method of the present invention, the charge amount and the charge distribution of which can be easily controlled. It has features such as rapid rise of charging, excellent developability and transferability, and is also suitable as a color developer. The charge exchange controlling agent used in the present invention is:
Used in addition to the developer, a carrier that imparts charge to the toner, a charging member such as a charging blade, or a fixing roll, a cleaning member, a toner hopper, and other printers for copying machines that contact the toner to electrically affect the toner. It can also be used by adding to each constituent member. [Examples] Hereinafter, the production method of the developer composition of the present invention will be described with reference to Examples and Comparative Examples. In addition,
Parts in the following examples represent parts by weight. Comparative Example 1 100 parts of styrene / n-butyl methacrylate copolymer (Tg = 65 ° C., Mn = 8000, Mw = 42000) 4 parts of magenta pigment (Carmine 6B) were melt-kneaded, pulverized and classified. A toner having an average particle diameter d ₅₀ = 12 μm was obtained. The toner is mixed with an iron powder carrier having an average particle size of about 100 μm (weight ratio of carrier / toner = 100/3), and the average charge amount by a blow-off tribo method and the chargeability such as charge distribution by a charge spectrograph method are measured. The test was performed in each environment of normal temperature and normal humidity, high temperature and high humidity, and low temperature and low humidity. Table 1 shows the results. [Table 1] Normal temperature and normal humidity High temperature and high humidity Low temperature and low humidity Flow-off charge amount -21 μc / g -7 μc / g -20 μc / g Rising state of charging △ △ × amount of toner of opposite polarity ○ △ × The fluctuation was large, and the rising speed of charging and the amount of toner of opposite polarity were also unsatisfactory. [0034] Example 1 Styrene / n-butyl methacrylate copolymer (Comparative Example 1 and the same) 100 parts Magenta pigment (Comparative Example 1 and the same) 4 parts tetraphenylboron 1 part of sodium same manner as in Comparative Example 1 Into a toner (average particle diameter d ₅₀ = 12)
μm) The charging characteristics were evaluated in the same manner. Table 2 shows the results
The results are shown in [Table 2] Normal temperature and normal humidity High temperature and high humidity Low temperature and low humidity Flow off charge amount -16 μc / g -12 μc / g -15 μc / g Rise of charging ○ ○ ○ Amount of reverse-polarity toner ○ ○ ○ The sharpness of chargeability, the rise of charge and the sharpness of charge distribution were greatly improved, and extremely good chargeability was exhibited. To this toner,
Further, 0.7% by weight of a hydrophobic silica fine powder and 0.8% by weight of a fatty acid metal salt are added and mixed to form a color developer in combination with a ferrite carrier having an average particle size of about 70 μm, and 5,000 sheets are obtained with an FX-2300 machine (manufactured by Fuji Xerox). When a continuous copying test was performed, an extremely clear magenta color image without fog was obtained stably. Example 2 4 parts of the magenta pigment of Example 1 were replaced with 4 parts of a cyan pigment (copper phthalocyanine), 4 parts of a yellow pigment (disazo yellow) and 7 parts of carbon black, respectively. A cyan toner, a yellow toner and a black toner of ₅₀ = 12 μm were obtained. The charging characteristics of these three color toners were evaluated in the same manner as in Example 1. In the case of cyan, -13 μc / g was obtained in all environments.
To -17 μc / g, and -12 μc / g for yellow.
g to -15 μc / g, -14 μc / g for black
-17 [mu] c / g, which is stable to the environment, and there is no problem in the rising of the charge and the amount of the opposite polarity toner. Example 3 Diameter 20 having a surface layer composed of a crosslinked phenolic resin, a reinforcing agent and carbon black and having an electric resistivity of about 10 ¹¹ Ωcm.
mm development roll, a toner supply roll composed of conductive rubber for supplying toner on the development roll, and having a surface layer composed of silicon rubber, a reinforcing agent and a charge control agent,
A blade that regulates the thickness of the toner layer and imparts a charge to the toner, wherein the toner is mainly mechanically supplied to the developing roll by a toner supply roll, and then the toner is charged by the blade pressed against the developing roll; A modified FX-2300 copier (manufactured by Fuji Xerox Co., Ltd.) incorporating a one-component developing device that forms an almost single upper toner layer, is conveyed to the electrostatic latent image portion by mirror image force, and is developed. As a toner, a continuous copy test of 5,000 sheets was performed using a mixture obtained by externally adding 1.0% by weight of hydrophobic silica fine powder to the magenta toner of Example 1 without using a carrier. Very good images were obtained. REFERENCE EXAMPLE 1 100 parts of a polyester resin (Tg = 60 ° C., chloroform-insoluble gel fraction = 15%), 10 parts of carbon black, 1 part of tetramethylammonium salt of dicatechol borate are melt-kneaded, pulverized and classified. , D ₅₀ = 9 μm, and mixed with a ferrite carrier having a particle size of about 80 μm (weight ratio of carrier / toner = 100/3). The charging characteristics were evaluated in the same manner as in Example 1. The blow-off charge amount was stable from −17 μc / g to −21 μc / g in all environments, the charge rise was fast, and almost no reverse polarity toner was observed. This toner was externally mixed with 0.7% by weight of hydrophobic silica fine powder and 0.7% by weight of methyl methacrylate-based resin fine powder, and subjected to a repetitive copy test of 10,000 copies with an FX-2300 copier. Was done. Reference Example 2 Styrene / butyl acrylate copolymer (Tg = 60 ° C., Mn = 4000, Mw = 15000) 50 parts Styrene / butyl acrylate copolymer (Tg = 60 ° C., Mn = 160,000, Mw) 50 parts ・ 5 parts of low molecular weight polypropylene ・ 100 parts of γ-Fe ₂ O ₃ fine powder 100 parts ・ 2 parts of tetramethylammonium salt of dicatechol borate are melt-kneaded, pulverized and classified, and the average particle diameter d ₅₀ = 12 μm Was obtained. 0.4% by weight of hydrophobized alumina fine powder and 0.1% by weight of tin oxide fine powder
FX-28 equipped with a magnetic one-component developing machine
When a continuous copy test of 5,000 sheets was performed with 30 units, extremely clear sepia images were obtained.

Claims (1)

(57) [Claims] General formula (In the formula, R ₁ , R ₂ , R ₃ and R ₄ are mutually independent organic groups and may be the same, and R ₁ and R ₂ and R ₃ and R ₄ are each a bond. And an organic anionic component (A) represented by the following formula: and a hydrogen cation or alkali having a smaller molecular size than the organic anionic component (A). An organic boron compound (AD) composed of a metal cation, an alkaline earth metal cation, a zinc cation, a cadmium cation, and a cationic component (D) selected from organic amine cations, sulfonium cations and phosphonium cations. A negatively chargeable charge exchange controlling agent in the toner particles such that the average charge amount of the toner by a blow-off tribo method is -12 μc / g or more. Method for producing a negatively chargeable developer composition according to symptoms.