JP3286706B2 - Electrostatic image developing toner and electrostatic image developer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner and a developer useful for developing an electrostatic image formed by electrophotography.

[0002]

2. Description of the Related Art After uniformly charging a photoreceptor by electrophotography, the photoreceptor is exposed to a light image based on an original drawing.
An electrostatic charge image corresponding to the original figure is formed on the photoreceptor by reducing or reducing the charge of the light-irradiated portion, and this electrostatic charge image is visualized by a so-called two-component developer composed of carrier particles and toner particles. The method of obtaining a copy by hand is generally well known.

[0003] In this two-component developer, fine toner particles are held on the surface of relatively large carrier particles by electric force generated by friction between the two particles, and the developer approaches an electrostatic latent image. Then, the attractive force of the electric field formed by the electrostatic latent image in the latent image direction with respect to the toner particles overcomes the coupling between the toner particles and the carrier particles, and only the toner particles are attracted and adhered to the electrostatic latent image to be static. The latent image is visualized.

The characteristics required of the toner include chargeability, hygroscopicity, stability over time, and fluidity. Of these properties, the chargeability, moisture absorption, and stability over time are the characteristics of the toner. It is greatly affected by the charge control agent contained therein. Conventionally, as a charge control agent for a toner, a Cr-containing or Co complex (JP-A-61-2) has been used as a load control agent.
17061, JP-A-63-216061), nitrohumic acids (JP-A-50-133838), phthalocyanine pigments (JP-A-60-25856)
No. 0), and as a positive charge control agent, nigrosine dye salts (JP-A-56-22441), various quaternary ammonium salts (JP-A-59-136747),
Although imidazole derivatives (Japanese Unexamined Patent Publication No. 3-72373) and the like are known, toners using these control agents do not have sufficient chargeability, hygroscopicity, and stability over time, and are not compatible with the binder of the control agent itself. Is not enough. For example, a toner using a known nigrosine dye as a positive charge control agent,
Although it has a relatively high charged power per se, it has poor adhesion to a substrate (paper), and has the drawback that it can be used only for toner of a hue whose application range is limited because it is black. Further, some toners using quaternary ammonium salts have extremely high hygroscopicity, and as a result, have the drawback that they lack stability over time and are inferior in ability to form images repeatedly.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above circumstances, and has low hygroscopicity, has stability over time, and as a result, has environmental characteristics and durability such as repetitive image forming properties. It is an object of the present invention to obtain a toner and a developer for developing an electrostatic charge image having excellent characteristics.

[0006]

According to the present invention, there is provided a toner for an electrostatic image comprising a resin and a colorant as main components.
A toner for developing an electrostatic image, comprising a nickel dithiolate complex represented by the following general formula (I) is provided.

Embedded image Further, according to the present invention, there is provided an electrostatic image developer comprising the toner and the carrier.

Hereinafter, the present invention will be described in detail. First, the nickel dithiolate complex used in the toner of the present invention has the general formula (II) or (II) as shown in Table 1 below.
The neutral nickel complex ((IV) and (V)) synthesized by heating and refluxing dithiolate sodium salt and nickel nitrate shown in I) in an organic solvent is heated and refluxed in dimethoxyethane to coordinate It can be manufactured by exchanging a child. The obtained complex can be produced by column chromatography or recrystallization.

[Table 1] Specific examples of the substituents R ₁ and R ₂ in the general formula (I) include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a t-butyl group, an n-hexyl group, A cyclohexyl group, an n-octyl group, an alkyl group such as n-dodecyl group, a substituted or unsubstituted phenyl group,
Examples include a benzyl group, an alkoxy group and a nitro group, a nitrile group, an ester group, a methylthio group, a phenylthio group, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Examples of the substituent for the phenyl group or the benzyl group include 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, and an n-propoxy group. And mono-, di- and trisubstituted alkoxy groups such as tert-butoxy group, nitro group, cyano group and halogen atom, and their alkyl groups, alkoxy groups, nitro groups, cyano groups and halogen atoms. As the heterocycle, pyridine,
Pyrrole, pyrimidine, imidazole, quinoline and the like. Examples of the cationic species X (+ ion) of the counter include hydrogen ions, alkali metal ions, various quaternary ammonium salts, phosphonium salts, and the like.

Since the toner and the developer for developing an electrostatic image of the present invention contain the nickel dithiolate complex represented by the general formula (I), the image quality is not deteriorated even after repeated continuous copying. Also, even when the environment such as temperature and humidity changes, the change in charging characteristics is small.

The following are specific examples of the nickel dithiolate complex which is the negative charge control agent of the present invention, but the present invention is not limited thereto.

[0010]

[Table 2- (1)]

[0011]

[Table 2- (2)]

[0012]

[Table 2- (3)]

[0013]

[Table 2- (4)]

Next, examples of resins that can be used in the present invention include polystyrene resins, acrylic resins, styrene-methacrylic copolymers, and epoxy resins.
As the coloring agent, for example, Kayaset Ye
llow E-L2R (manufactured by Nippon Kayaku, CI Pigm
ent Yellow 142), Kayaset R
ed AG (same as CI Solvent 17)
9), Kayset Blue FR (same as CI.
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, based on 100 parts by weight of the resin component. If the amount is less than 0.5 part by weight, a problem tends to occur in terms of a sufficient offset prevention effect.
If the amount is more than 0 parts by weight, gelation may occur, which is not preferable. In addition, polypropylene, polyethylene, fixing properties improver such as carnauba wax, hydrophobic silica, alumina,
Various additives such as a fluidity improver such as molybdenum sulfide and titanium oxide, and a cleaning improver such as zinc stearate, magnesium stearate and zinc laurate can be added. As the carrier, a magnetic material such as iron, nickel, cobalt, or ferrite is preferably used.

The toner of the present invention comprises the above resin, colorant,
The charge control agent is melted and kneaded by an apparatus capable of heating and mixing such as a heating kneader and a three roll, and then cooled and solidified, and then cooled by a pulverizer such as a jet mill or a ball mill.
It can be obtained by grinding to a particle size of μm. As another method, a resin is dissolved, a charge control agent is added thereto, and after stirring, it is poured into water and reprecipitated, then filtered, dried, and dried using a pulverizer such as a ball mill.
It can be obtained by grinding to a particle size of μm.

[0016]

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

Example 1 <Preparation of Toner> Styrene-methacrylate resin 100 parts Nickel dithiolate complex (exemplary compound 1) 5 parts Carbon black 10 parts

Example 2 <Formulation of Toner> 100 parts of polyester resin 8 parts of nickel dithiolate complex (exemplary compound 7) 8 parts of carbon black 10 parts

Example 3 <Preparation of Toner> Epoxy resin 100 parts Nickel dithiolate complex (Exemplary compound 16) 10 parts Carbon black 10 parts

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

The toner obtained above was used for EFV 200 to 300
It was mixed with mesh iron powder (manufactured by Nippon Iron Powder Co., Ltd.) and stirred to prepare electrostatic charge image developers having a toner concentration of 7%, and the following evaluation was performed.

1. Durability test The durability was measured using an electrophotographic copier (FT4060 manufactured by Ricoh).
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, and the image was evaluated.

2. Environmental test Regarding environmental characteristics, the toner and the carrier were conditioned under high humidity conditions (30 ° C., 90% humidity for 2 hours) and low humidity conditions (10 ° C., 30% humidity for 2 hours). In the same manner as described above, the toner and the carrier were mixed and stirred to prepare a developer for each, and the toner charge amount (μc / g) of the developer was measured to evaluate the rate of change between high humidity and low humidity. Table 3 shows the evaluation results.

[0024]

[Table 3] *: When copying 10,000 sheets **: Significant generation of background stain

[0025]

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

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Fuyuhiko Matsumoto 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Katsuji Maruyama 1-3-6 Nakamagome, Ota-ku, Tokyo (56) References JP-A-7-175259 (JP, A) JP-A-2-121997 (JP, A) (58) Fields studied (Int. Cl. ⁷ , DB name) G03G 9/08 CA (STN)

Claims (2)

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