JP2844101B2 - Negatively chargeable toner for electrophotography - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic toner, and more particularly, to an electrophotographic toner that exhibits stable negative charging characteristics and is excellent in developability and environmental characteristics.

[Conventional technology]

2. Description of the Related Art Conventionally, as a toner used in developing an electrostatic charge in electrophotography, a toner in which a colorant, a charge control agent, and the like are dispersed in a binder is generally used. For example, in the case of a two-component developer, the toner mixes a carrier such as iron powder, ferrite, and magnetite, and gives charge to the toner by frictional charging. The development characteristics greatly depend on the chargeability of the toner, and it is an issue of the electrophotographic system how to impart stable chargeability to the toner.

Negatively chargeable toners for electrophotography used in conventional two-component developers mainly use a metal salt or a metal complex compound as a charge control agent to control the chargeability. It is not always satisfactory in terms of value, change with time, and environmental dependency. For example, a styrene-acrylic polymer commonly used as a binder resin generally exhibits a negative charge characteristic of the polymer itself. May be higher. In this case, as a means for reducing to a desired charge amount, a large amount of a conductive additive such as carbon black is added to lower the toner resistance, or is used as a charge control agent for positive charging. In some cases, a nigrosine-based charge control agent is added. However, in any of the methods, the dispersibility of these additives in the binder is poor, and the charge amount of each toner particle becomes nonuniform. Was.

As a method of controlling the charge amount other than the above, a method of lowering the charge amount by setting the mixing ratio of the toner to the developer higher than an appropriate mixing ratio is also used. Also in this method, the charge amount of each toner particle is not uniform, and problems such as ground fog and toner scattering have occurred.

[Problems to be solved by the invention]

The present invention has been made to solve the above problems, and an object of the present invention is to provide a negatively chargeable toner for electrophotography having improved development characteristics and environment-dependent characteristics.

[Means for solving the problem]

The present invention relates to a copolymer resin containing a quaternary ammonium base component comprising at least a repeating unit represented by the following general formula (1): 0.01 to 10 parts by weight per 100 parts by weight of a resin component; Or a negatively chargeable toner for electrophotography, characterized by containing a metal complex salt compound.

(Wherein, R ₁ is hydrogen or a methyl group, R ₂ is an alkylene group,
R _{3 to} R ₅ represent an alkyl group, and Ph represents a phenyl group. Hereinafter, the present invention will be described in detail.

The unit of the general formula (1) according to the present invention is obtained by converting a dialkylaminoalkyl (meth) acrylate into a
And a unit derived from a quaternary ammonium base component in an amount of 3 to 35% by weight, preferably 5 to 22% by weight, based on the weight of the copolymer resin containing a quaternary ammonium base component. is there. The dialkylaminoalkyl (meth) acrylate is, for example, a di (lower alkyl) amino such as dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dipropylaminoethyl (meth) acrylate, dibutylaminoethyl (meth) acrylate. Ethyl (meth) acrylate.

The copolymer resin containing a quaternary ammonium base component used in the present invention can be produced by the following production method I or II.

Production Method I For example, a copolymer obtained by copolymerizing styrene and / or a styrene-substituted product, a dialkylaminoalkyl (meth) acrylate, and, if necessary, an alkyl (meth) acrylate in the presence of a polymerization initiator. Can be quaternized with an alkyl p-toluenesulfonate, for example, methyl p-toluenesulfonate, ethyl p-toluenesulfonate, propyl p-toluenesulfonate, or the like.

Production method II Dialkylaminoalkyl (meth) acrylate is preliminarily converted to an alkyl halide such as methyl chloride, methyl bromide, ethyl chloride, ethyl bromide, propyl chloride, prol bromide, butyl chloride, butyl bromide, etc. according to a conventional method. And by copolymerizing the quaternary ammonium halide with styrene and / or a substituted styrene, if necessary, with an alkyl (meth) acrylate, and reacting the resulting copolymer with p-toluenesulfonic acid. can do.

Examples of the styrene or the styrene-substituted product include styrene, α-methylstyrene, p-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, and p-methylstyrene. n-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3, 4-dichlorostyrene and the like.

Examples of the alkyl (meth) acrylate include methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, lauryl acrylate, and acrylic. 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, α-methyl methacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-methacrylate -Octyl, dodecyl methacrylate, lauryl methacrylate, 2-methacrylic acid
Examples include ethylhexyl, stearyl methacrylate, and phenyl methacrylate.

Examples of the polymerization initiator that can be used in the above copolymerization reaction include azo-based initiators such as azobisisobutyronitrile, azobisdimethylvaleronitrile, and azobis (2,4-dimethyl-4-methoxyvaleronitrile). , 2-phenylazo (2,4-dimethyl-4-methoxyvaleronitrile) and the like.

As the polymerization method, any of solution polymerization, suspension polymerization and bulk polymerization can be used.

In the present invention, the copolymer resin containing the quaternary ammonium base component is used in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the resin body.
It is contained in parts by weight, and the content is adjusted so as to have an appropriate charge amount according to the developing conditions of the copying machine and the printer to be used. Here, the resin component in the present invention refers to a resin obtained by combining a binder resin and a copolymer resin containing a quaternary ammonium base component. The content of the copolymer resin containing a quaternary ammonium base component is 0.
When the amount is less than 01 parts by weight, the negative charge of the negatively chargeable toner for electrophotography cannot be suppressed. On the other hand, when the amount is more than 10 parts by weight, the positive charge due to the quaternary ammonium base component-containing copolymer resin itself is not obtained. The electric charge becomes dominant, and problems such as ground fog tend to occur.

 Next, other constituent materials will be described in detail.

As the binder resin constituting the negatively chargeable toner for electrophotography of the present invention, styrenes such as styrene, parachlorostyrene, and methylstyrene, vinyl chloride, vinyl bromide, vinyl fluoride, vinyl acetate, vinyl propionate, Vinyl esters such as vinyl benzoate, methyl acrylate,
Isotyl acrylate, dodecyl acrylate, n-octyl acrylate, 2-chloro-ethyl acrylate, phenyl acrylate, α-methyl methyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dialkyl methacrylate Α- such as aminoethyl
Esters of methylene aliphatic monocarboxylic acid, acrylonilyl, methacrylonitrile, acrylamide such as vinyl methyl ether, vinyl isobutyl ether,
Homopolymers obtained by polymerizing monomers such as vinyl ketones such as vinyl methyl ketone and vinyl hexyl ketone, and N-vinyl compounds such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole and N-vinyl pyrrolidone; A copolymer or a mixture thereof obtained by copolymerizing two or more types of monomers, or a rosin-modified phenol formalin resin, an epoxy resin, a polyester resin, a polyurethane resin, a cellulose resin,
Examples thereof include non-vinyl-based thermoplastic resins such as polyether resins and mixtures of these with the above-mentioned vinyl resins. Among them, the use of a resin having the same composition as the copolymer resin containing a quaternary ammonium base component is more effective because the compatibility increases.

In addition, a metal salt or a metal complex compound is used as the charge control agent. Examples of metal salts or metal complex compounds that can be used in the negatively chargeable toner for electrophotography of the present invention are shown in the following formulas (2) to (7).

The colorant that can be used in the negatively chargeable toner for electrophotography of the present invention is not particularly limited, and can be selected from a wide range. For example, carbon black, nigrosine dye, aniline blue, chalco oil blue, and chromium Yellow, Ultramarine Blue, Dupont Oil Red,
Examples include quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, rose bengal, and mixtures thereof.

Further, the negatively chargeable toner for electrophotography of the present invention may further improve the anti-offset property as required, or a higher fatty acid or a metal salt of a higher fatty acid in order to release the releasability,
Natural or synthetic waxes, higher fatty acid esters or partially saponified products thereof, alkylenebisfatty acid amides, fluororesins, silicone resins and the like can be blended.

For the purpose of maintaining the fluidity and storage stability of the toner, colloidal silica, hydrophobic silica or the like may be applied to the surface of the negatively chargeable toner for electrophotography.

The negatively chargeable toner for electrophotography of the present invention is obtained by sufficiently mixing the above-described materials with a mixer such as a Henschel mixer or a ball mill, and then melting and kneading the mixture in a heat kneader such as a heating roll, a kneader, or an extruder. And solidify by cooling
Pulverization is carried out with a pulverizer such as a hammer mill or a jet mill, and then the pulverizer can be adjusted as a 5 to 20 μm toner particle in a classifier.

The negatively chargeable toner for electrophotography of the present invention can be used as a two-component developer by mixing with a carrier such as iron or ferrite. It can also be used as an agent.

(Operation)

The copolymer resin containing a quaternary ammonium base component of the general formula (1) used in the present invention has a positive chargeability, effectively functions to suppress negative chargeability, and It is also possible to use the polymer resin itself as the binder resin. Further, even if the toner is melt-mixed with another binder resin, the compatibility is extremely excellent, so that the distribution of the charge amount when the toner is formed becomes very good.

In particular, when used as a mixture with a binder resin, the closer the composition of the binder resin and the composition of the monomer copolymerizing the copolymer resin containing the quaternary ammonium base component, the better the compatibility. . Therefore, it is possible to avoid problems such as fogging and toner scattering caused by poor dispersion of additives in the related art.

Further, in the method of controlling the negative chargeability by adding an additive to the toner, a color toner of a desired color cannot be obtained because the additive itself is colored. However, since the copolymer resin containing a quaternary ammonium base component used in the present invention is colorless, it is possible to cope with all color toners with a colorant having a desired color.

The negatively chargeable toner for electrophotography of the present invention has a large effect particularly when used in combination with a so-called coating carrier in which the surface of the carrier is coated with a resin. The reason is that the coating carrier originally has a long life and good image characteristics, but on the other hand, it has high resistance due to the resin coating, so that charge accumulation in a low-temperature and low-humidity environment is remarkable, and the image density decreases due to an increase in charge amount and Fogging had occurred. Therefore, when the negatively chargeable toner for electrophotography of the present invention is used in combination with the coating carrier, the charge on the surface of the coating carrier is offset, and as a result, the increase in the negative charge of the toner can be suppressed, and the environment is affected. As a result, good image characteristics can be obtained.

〔Example〕

Hereinafter, the present invention will be described more specifically based on examples.

First, main materials used in the examples are shown below.

(Monomer composition)

Copolymer resin B [monomer composition] Copolymer resin C [monomer composition] Copolymer resin D [monomer composition] [II] Binder resin Styrene-acrylic copolymer resin A [Monomer composition] Styrene-acrylic copolymer resin B [monomer composition] Examples 1 to 6 and Comparative Examples 1 to 3 Next, the above materials were used, and the mixture having the composition shown in Table 1 was hot-melt-kneaded and then pulverized and classified to have an average particle diameter of 11 μm.
m of the electrophotographic unchargeable toner of the present invention and a comparative toner.

Next, 3 parts by weight of each of the negatively chargeable toner for electrophotography of the present invention based on Examples 1 to 6 and the comparative toner based on Comparative Examples 1 to 3 obtained from the above were added to a silicone-coated ferrite carrier (manufactured by Powder Tech Co., Ltd.). FL95-100) to prepare a developer.

These developers were used in commercial copying machines (SF-97 manufactured by Sharp Corporation).
50), and a continuous copy test of up to 50,000 sheets was performed. Table 2 shows the results. Similarly, a reverse copy type printer (TN-7300 manufactured by Toshiba Corporation) was installed and a continuous copy test was performed on up to 50,000 sheets. The results are shown in Table 3.

Furthermore, the negatively chargeable toner for electrophotography of the present invention and the toner for comparison were allowed to stand for 24 hours under the environmental conditions shown in Table 4, and then mixed with the silicone-coated ferrite carrier under the environmental conditions to prepare a developer. It was fabricated and initially specified for evaluation. Table 5 shows the results.

The image density in each table is the value measured on the image area with a Macbeth reflection densitometer, the background fog is the value measured on a non-image area with a Hunter whiteness meter, and the toner scattering is the area around the developing tank after the continuous copy test. The part was visually evaluated.
(○: no toner scattering, ×: toner scattering) As is evident from the results in Tables 2, 3 and 5, the negatively chargeable toner for electrophotography of the present invention has a stable image density up to 50,000 sheets irrespective of a copying machine or a printer.
There was little ground fogging and no toner scattering, showing good characteristics under any environmental conditions. On the other hand, the toner of Comparative Example 1 had low image density after 50,000 sheets and low image density under low-temperature and low-humidity environment conditions. Further, in Comparative Examples 2 and 3, a large amount of ground fogging occurred after 50,000 sheets, toner scattering was poor, and ground fogging occurred under high-temperature, high-humidity environmental conditions or low-temperature, low-humidity conditions. It was cool.

〔The invention's effect〕

The present invention can provide a negatively chargeable toner for electrophotography that has good development characteristics such as image density and background fog and that can obtain stable development characteristics even when environmental conditions change.

Continuation of front page (56) References JP-A-60-217370 (JP, A) JP-A-3-80259 (JP, A) JP-A-3-175456 (JP, A) JP-A-2-22670 (JP) JP-A-1-204060 (JP, A) JP-A-2-167565 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 9/08 CA (STN)

Claims (1)

(57) [Claims] (1) a copolymer resin containing a quaternary ammonium base component comprising at least a repeating unit represented by the following general formula (1): 0.01 to 10 parts by weight per 100 parts by weight of a resin component; A negatively chargeable toner for electrophotography, comprising a salt or a metal complex salt compound. (Wherein, R ₁ is hydrogen or a methyl group, R ₂ is an alkylene group,
R _{3 to} R ₅ represent an alkyl group, and Ph represents a phenyl group. )