JP2814510B2 - Electrostatic toner - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic charge developing toner used for developing an electrostatic latent image in an apparatus to which an electrophotographic method is applied, such as a copying machine and a printer. More specifically, the present invention relates to a negatively chargeable toner for electrostatic charge development containing a specific compound.

[Conventional technology]

Electrophotography is described in U.S. Pat.No. 2,976,691 and JP-B-42-23910.
As disclosed in various publications such as Japanese Patent Application Publication No. JP-B-43-24748 and JP-B-43-24748, an electrostatic latent image is generally formed on a photoconductor containing a photoconductive material by various means, and then the latent image is formed. The phenomenon occurs as a powder image with toner, and the powder image is transferred to paper or the like as necessary, and then fixed by heating, pressurizing, or solvent vapor.

Particles obtained by dispersing a colorant (a dye or pigment such as carbon black) in various resins and finely pulverized to about 1 to 30 μm are usually used as the toner used in the electrophotographic method. The toner is used in a mixture with a carrier material such as glass beads, iron powder or fur.

[Problem to be solved by the invention]

These toners are required to have the following characteristics.

・ Excellent triboelectricity.

-The characteristics do not change significantly depending on the environment such as temperature and humidity, that is, there is little environmental dependency.

-Deterioration is less for repeated continuous use.

However, in practice, it is difficult to satisfy all the above-mentioned required characteristics, and at present, there is a continuous demand for improvement of toner.

[Means for solving the problem]

The present invention has been made in view of such circumstances, and an object of the present invention is to provide an electrostatic charge developing toner having excellent environmental resistance and durability.

The present inventors have conducted intensive studies to achieve such an object, and as a result, have found that the above object can be satisfied by incorporating a compound having a specific structure into a binder resin in a toner containing the resin. The invention has been reached.

That is, the gist of the present invention resides in a toner for electrostatic charge development comprising a resin and a compound represented by the following general formula (I).

Wherein X ^{1 to} X ⁴ are each a hydrogen atom or (Wherein, R ¹ represents an alkyl group having 1 to 5 carbon atoms, R ² represents an alkoxy group having 1 to 5 carbon atoms, and n represents any integer of 0 to 4). However, the case where all of X ^{1 to} X ⁴ are hydrogen atoms is excluded. [Operation] Hereinafter, the present invention will be described in detail.

The electrostatic charge developing toner of the present invention is characterized by containing a resin and a copper phthalocyanine compound represented by the general formula (I). Preferred specific examples of the substituents represented by X ^{1 to} X ⁴ in the general formula (I) include: And the like.

The copper phthalocyanine-based compound represented by the general formula (I) is not limited to any one of the compounds of the present invention except that all the substituents represented by X ^{1 to} X ⁴ are hydrogen atoms, that is, they are 1 to 4 substituents. However, it is more preferable to use any one of the 2- to 4-substituted products or a mixture thereof, and the content in the toner is 0.1 to 20% by weight, preferably 0.5 to 10% by weight based on the resin.
It is better to be wt%. The copper phthalocyanine-based compound uniformly charges the toner to a negative polarity which is stable against a change in humidity, and thus is extremely effective in preventing fog due to generation of an uncharged or weakly charged toner. The toner for electrostatic charge development of the present invention may be a known toner colorant other than the usual resin and the compound represented by the general formula (I), ie, carbon black, copper phthalocyanine pigment, phthalocyanine green, malachite green, rhodamine, oil It is common to use colorants such as black, benzine yellow, quinacridone pigments, various dyes and pigments such as navy blue and carmine 6B, and use them as black toners or color toners of each color. Since the compound represented by the formula itself exhibits a clear blue color, it can be used as a cyan toner without using another coloring agent.

On the other hand, the binder resin to be contained in the toner for electrostatic charge development of the present invention can be selected from a wide range including known toner resins. Specifically, styrene-based resins such as polystyrene, styrene-acrylate copolymer, styrene-methacrylate copolymer and styrene-butadiene copolymer, saturated polyester resin, unsaturated polyester resin, epoxy resin Examples thereof include phenol resins, coumarone resins, chlorinated paraffins, xylene resins, vinyl chloride resins, polyethylene, and polypropylene. These resins may be used as a mixture of two or more. Among these, use of a styrene resin, a saturated or unsaturated polyester resin, or an epoxy resin is advantageous.

The compound of the general formula (I) used in the present invention has a good negative charge property. If necessary, a known negative electrode such as a metal complex of salicylic acid or alkyl salicylic acid with Cr, Zn or Al is used. Neutral charge control agent in the toner.
You may make it contain in the range of 1-5 wt%.

In the present invention, a fluidity improver such as colloidal silica may be added in an amount of about 0.01 to 3% by weight based on the toner.

In addition, a cleaning aid such as a metal stearate may be appropriately added.

The toner of the present invention can be produced by employing any conventionally known method for producing a toner. For example, the following examples are given as typical production methods.

First, a resin and a compound represented by the general formula (I) (an additive such as a charge control agent may be optionally added) may be uniformly mixed with a ball mill, a V-type mixer, an S-type mixer, a Henschel mixer, or the like. Disperse in. Next, the dispersion is melt-kneaded with a double-arm kneader, a pressure kneader or the like. The mixture is pulverized by a pulverizer such as a hammer mill, a jet mill, and a ball mill,
Further, the obtained powder is classified by an air classifier or the like.

The toner of the present invention is preferably used as a two-component developer by being mixed with a carrier.
In some cases, it is possible to add and disperse a magnetic substance such as magnetite powder and use it as a normal one-component toner (magnetic toner).

As the carrier, conventionally known carriers such as iron powder and ferrite powder having a particle size of about 50 to 200 μm can be used. Further, those having a surface coated with a silicone resin, an acrylic resin, a fluorine-based resin, or the like, or a mixture of these resins can also be suitably used.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist. In addition, in each of Examples and Comparative Examples, “parts” simply means “parts by weight”.
The copper phthalocyanine compound used as a material in each Example is a mixture containing di-substituted and tetra-substituted compounds at a molar ratio of about 1: 1.

Example 1 Styrene / n-butyl acrylate copolymer (monomer ratio: 8/2, weight average molecular weight: 60,000) 100 parts Copper phthalocyanine compound having the substituent (a) 2 parts Carbon black (MA-600, manufactured by Mitsubishi Kasei Co., Ltd.) 5 parts) The above-mentioned materials were melt-kneaded by a hot roll mill, cooled, coarsely ground by using a hammer mill, and then finely ground by an air jet-type fine mill. The resulting fine powder was classified and particles having a particle size of 5 to 20 μm were selected to obtain a toner.

To 3 parts of this toner, 97 parts of a carrier (ferrite powder coated with a silicone resin and having an average particle size of about 100 μm) were mixed with a V blender to prepare a developer. The charge amount of this developer by a blow-off method was -13 μC / g.

Using this developer, a continuous actual shooting test was performed using a commercially available dry copying machine using selenium as the photoconductor.
Even after copying 30,000 sheets, a clear copy of the image was obtained, and it was found that it had excellent durability.

On the other hand, using this toner and the ferrite carrier, a developer was mixed at a high temperature and a high humidity of 35 ° C. and 85% RH. The charge amount at that time was −13 μC / g, and it was also found that there was no change in the triboelectric charging characteristics with respect to the humidity change.

Example 2 A developer having a charge amount of −12 μC / g was obtained in the same manner as in Example 1 except that a copper phthalocyanine compound having the substituent (b) was used instead of the substituent (a). Was. In addition, a clear copy was obtained even after the continuous shooting test of 30,000 sheets.

Example 3 100 parts of a polyester resin synthesized from bisphenol A and fumaric acid (weight average molecular weight: 8000) 100 parts Copper phthalocyanine compound having the substituent (c) 5 parts Carbon black (Mitsubishi Kasei Co., # 40) 5 parts Toner production The charge amount was −18 μC / g by the same operation as in Example 1 except that the above-mentioned materials were used as the materials for
Was obtained. Further, even after continuous shooting of 20,000 sheets, a clear copy was obtained without any decrease in image density or increase in fog. The charge amount at that time was almost the same as the initial charge, and was stable.

Example 4 A developer having a charge amount of −20 μC / g was obtained in exactly the same manner as in Example 3 except that carbon black was removed from the toner production material. Using this developer, an actual photographing test was performed in exactly the same manner as in Example 3, and a clear blue copy was obtained. In addition, it was found that a good copy without image quality deterioration was obtained even after continuous actual shooting of 20,000 sheets, and it had high durability.

Comparative Example 1 A developer was manufactured in exactly the same manner as in Example 1 except that the copper phthalocyanine compound was omitted from the toner manufacturing material.
When the actual printing test was performed, the charge amount of the developer was -2 μC /
There was only g, and fog was intense from the beginning in live action, and a clear copy could not be obtained.

〔The invention's effect〕

The electrostatic charge developing toner of the present invention enables clear copying with sufficient image density and little fog, does not change its triboelectric charging characteristics even under high humidity, and has excellent durability when used repeatedly. It is a thing.

──────────────────────────────────────────────────の Continuation of the front page (72) Inventor Hirofumi Oda 370 Yenzo, Chigasaki City, Kanagawa Prefecture Inside the Information Equipment Center, Chigasaki Office, Mitsubishi Kasei Co., Ltd. (56) References JP-A-57-54954 (JP, A) JP-A-52-45931 (JP, A) JP-A-49-91231 (JP, A) JP-B-54-1464 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 9/00-9/10 362

Claims (1)

(57) [Claims] 1. An electrostatic charge developing toner comprising a resin and a compound represented by the following general formula (I). Wherein X ^{1 to} X ⁴ are each a hydrogen atom or (In the formula, R ¹ represents an alkyl group having 1 to 5 carbon atoms, R ² represents an alkoxy group having 1 to 5 carbon atoms, n represents represents an integer of 0 to 4.) However, X ¹ Except when all of X ⁴ are hydrogen atoms. ]