JPH0815912A - Toner for developing electrostatic charge image and electrostatic charge image developer - Google Patents

Abstract

PURPOSE:To obtain toner and a developer excellent in durability and environmental resistance. CONSTITUTION:A nickel dithiolate complex represented by the formula is incorporated into the toner of an electrostatic charge image developer based on a resin and a colorant to obtain the objective toner and the objective electrostatic charge image developer contains this toner and a carrier. In the formula, X<+> is an H ion or a cation, (n) is 1 or 2, each of R1 and R2 which may be different is H, 1-20C alkyl, optionally substd. phenyl, an optionally substd. alicyclic group, nitro, nitrile, ester, alkoxy, amino, chalcogenide or halogen, R1 and R2 may form a ring by bonding to each other and both of them are not optionally substd. phenyl.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to toners and developers useful for developing electrostatic images formed by electrophotography.

[0002]

2. Description of the Related Art A photoconductor is uniformly charged by an electrophotographic method, and then a photoimage based on an original image is exposed on the photoconductor.
An electrostatic charge image corresponding to the original image is formed on the photoconductor by reducing or reducing the charge in the light irradiation area, and this electrostatic charge image is visualized by a so-called two-component developer consisting of carrier particles and toner particles. The method of obtaining a copy by using the method is generally well known.

In this two-component developer, fine toner particles are held on the surface of a relatively large carrier particle by an electric force generated by friction between the particles, and the developer is brought close to an electrostatic latent image. Then, the attractive force of the electric field formed by the electrostatic latent image on the toner particles in the direction of the latent image overcomes the bond between the toner particles and the carrier particles, and only the toner particles are attracted and adhered onto the electrostatic latent image and statically absorbed. The latent image is visualized.

The properties required for this toner include chargeability, hygroscopicity, stability over time, fluidity, and the like. Among these properties, the chargeability, hygroscopicity, and stability over time are toners. It is greatly affected by the charge control agent contained therein. Conventionally, as a charge control agent for toner, as a negative charge control agent, a Cr-containing or Co complex (Japanese Patent Application Laid-Open No. 61-2)
17061, JP-A-63-216061), nitrohumic acids (JP-A-50-133838), phthalocyanine pigments (JP-A-60-25856).
No. 0) and the like, and as a positive charge control agent, a nigrosine dye salt (JP-A-56-22441), various quaternary ammonium salts (JP-A-59-136747),
Imidazole dielectrics (Japanese Patent Laid-Open No. 3-72373) and the like are known, but toners using these control agents have insufficient chargeability, hygroscopicity, and stability over time, and are not compatible with the binder of the control agent itself. Solubility is hard to say. For example, a toner using a known nigrosine dye as a positive charge control agent is
Although it itself has relatively high electric power, it has a drawback that it has poor adhesion to a substrate (paper) and can be used only for toner of a hue whose application range is limited because it is black in itself. Further, some of the toners using the quaternary ammonium salt have a very high hygroscopicity, and as a result, there is a defect that they lack stability over time and are inferior in repetitive image forming ability.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances and has a low hygroscopic property and a stable stability over time, and as a result, has a repetitive image forming property and is environmentally friendly and durable. It is an object of the present invention to obtain a toner and a developer for developing an electrostatic image which are excellent in

[0006]

According to the present invention, in an electrostatic charge image toner containing a resin and a colorant as main components,
Provided is a toner for developing an electrostatic charge image, which comprises a nickel dithiolate complex represented by the following general formula (I).

Embedded image Further, according to the present invention, there is provided an electrostatic image developer containing the above-mentioned toner and carrier.

The present invention will be described in detail below. The nickel dithiolate complex used in the toner of the present invention is a neutral nickel complex synthesized by heating and refluxing sodium dithiolate salt represented by the following general formula (II) and nickel nitrate in an organic solvent, It can be obtained by column chromatography or recrystallization after iodine oxidation and crystallization with the corresponding onium salt.

Embedded image (In the formula, R ₁ and R ₂ are the same as in the case of the compound of the general formula (I).) Specific examples of the substituents R ₁ and R ₂ in the general formula (I) include a methyl group, an ethyl group, and n. -Propyl group, i-propyl group, n-butyl group, t-decyl group, n-hexyl group, cyclohexyl group, n-octyl group, n-dodecyl group and other alkyl groups, substituted or unsubstituted phenyl group,
Examples thereof include benzyl group, alkoxy group and nitro group, nitrile group, ester group, methylthio group, phenylthio group, fluorine atom, chlorine atom, bromine atom, iodine atom and the like. Further, as the substituent for substituting the phenyl group and the benzyl group, an alkyl group such as a methyl group, an ethyl group, an n-propyl group, an n-butyl group, and a t-butyl group, a methoxy group, an ethoxy group, an n-propoxy group. , An alkoxy group such as t-butoxy group, a nitro group, a cyano group, a halogen atom, and an alkyl group, an alkoxy group, a nitro group, a cyano group, and a mono-substituted, di-substituted or tri-substituted product of a halogen atom. Examples of the cation species X (+ ion) of the counter include hydrogen ions, alkali metal ions, various quaternary ammonium salts, phosphonium salts, and the like.

Since the electrostatic image developing toner and developer of the present invention contain the nickel dithiolate complex represented by the general formula (I), the image quality does not deteriorate even when repeated continuous copying is performed. In addition, even if the environment such as temperature and humidity changes, the charging characteristic does not change much.

Specific examples of the nickel dithiolate complex which is the load charge control agent of the present invention are listed below, but the present invention is not limited thereto.

[0010]

[Table 1]

Next, examples of resins that can be used in the present invention include polystyrene resins, acrylic resins, styrene-methacrylic copolymers, and epoxy resins.
Further, as the coloring agent, for example, Kayase Ye
low E-L2R (manufactured by Nippon Kayaku, CI Pigm
ent Yellow 142), Kayaset R
ed A-G (the same, CI Solvent 17
9), Kayase Blue FR (ibid., C.I.
Solvent Blue 105), carbon black, and the like, but are not limited thereto. The content of the compound (1) of the present invention is 0.5 to 30 parts by weight, preferably 1 to 10 parts by weight with respect to 100 parts by weight of the resin component. If it is less than 0.5 part by weight, a problem tends to occur in terms of sufficient offset prevention effect.
If it is 0 parts by weight or more, gelation may occur, which is not preferable. Further, fixability improvers such as polypropylene, polyethylene, carnauba wax, hydrophobic silica, alumina,
Various additives such as fluidity improvers such as molybdenum sulfide and titanium oxide, and cleaning improvers such as zinc stearate, magnesium stearate and zinc laurate can be added. As the carrier, magnetic materials such as iron, nickel, cobalt and ferrite are preferably used.

The toner of the present invention comprises the above resin, colorant,
The charge control agent is melted and kneaded by a device capable of heating and mixing such as a heating kneader and three rolls, and then cooled and solidified, and then the amount is 1 to 50 by a pulverizer such as a jet mill and a ball mill.
It can be obtained by pulverizing to a particle size of μm. As another method, a resin is dissolved, a charge control agent is added thereto, and after stirring treatment, it is poured into water for reprecipitation, followed by filtration and drying, and then using a pulverizer such as a ball mill for 1 to 50.
It can be obtained by pulverizing to a particle size of μm.

[0013]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto. In addition, the part in an Example represents a weight part. Each of the following formulations is blended, kneaded on a hot roll, pulverized and classified to have an average particle size of 8.0.
The toners of Examples and Comparative Examples having a size of μm were prepared.

Example 1 <Toner formulation> Styrene-methacrylate resin 100 parts Nickel dithiolate complex (Exemplified Compound 3) 5 parts Carbon black 10 parts

Example 2 <Toner formulation> Polyester resin 100 parts Nickel dithiolate complex (Exemplified compound 6) 8 parts Carbon black 10 parts

Example 3 <Toner formulation> Epoxy resin 100 parts Nickel dithiolate complex (Exemplified compound 10) 10 parts Carbon black 10 parts

Comparative Example <Toner Formulation> Styrene-methacrylate resin 100 parts Metal-containing monoazo dye (Spirone Black TOH manufactured by Hodogaya Chemical Co., Ltd.) 10 parts Carbon black 10 parts

The toner obtained above is EFV200-300.
It was mixed with mesh iron powder (manufactured by Nippon Iron Powder Co., Ltd.) and stirred to prepare an electrostatic charge image developer having a toner concentration of 7%, and the following evaluations were performed.

1. Durability test Durability is measured by an electrophotographic copying machine (FT4060 made by Ricoh).
Then, 20,000 sheets were continuously copied, and the toner charge amount (μC / g) of the developer at the initial stage and after the copying was measured to evaluate the image.

2. Environmental test As for environmental test, after toner and carrier are conditioned under high humidity condition (30 ° C, 90% humidity for 2 hours) and low humidity condition (10 ° C, 30% humidity for 2 hours). The toner and the carrier were mixed and agitated in the same manner as above to prepare a developer for each, and the toner charge amount (μc / g) of the developer was measured, and the fluctuation rate at high humidity and low humidity was evaluated. Table 2 shows the evaluation results.

[0021]

[Table 2] *: At the time of copying 10000 sheets **: Significant scumming occurs

[0022]

INDUSTRIAL APPLICABILITY The toner and developer for developing an electrostatic image containing the nickel dithiolate complex of the present invention have little fluctuation in charging characteristics due to the environment, and the image quality does not deteriorate even after repeated continuous copying. .

Front Page Continuation (72) Inventor Fuyuhiko Matsumoto 1-3-6 Nakamagome, Ota-ku, Tokyo Within Ricoh Co., Ltd. (72) Inventor Katsuji Maruyama 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. Within

Claims (2)

[Claims] 1. A toner for developing an electrostatic charge image, which comprises a nickel dithiolate complex represented by the following general formula (I) in a toner for an electrostatic charge image containing a resin and a colorant as main components. Embedded image 2. An electrostatic image developer containing the toner according to claim 1 and a carrier.