JPH05173365A - Electrostatic charge image developer - Google Patents

Abstract

PURPOSE:To provide an electrostatic charge image developer having stable density and charges of the toner with which negative electrostatic latent images are stably developed into high picture qualities with proper density and little fog, by using a ketone resin having a specified structure as a binder resin of the toner and using a fluorine resin as the main component of the coating layer of the carrier. CONSTITUTION:This electrostatic charge image developer consists of a toner and a carrier. The toner consists of such agents which give characteristics to the toner, and are a coloring agent, charge controlling agent, magnetic particles, etc., dispersed in a binder resin. It is required to incorporate a cyclohexanone-base ketone resin expressed by formula into the binder resin. The carrier is a coated carrier comprising magnetic core particles the surfaces of which are coated with coating layers essentially comprising a fluorine resin. The amt. of the carrier used is preferably 10-100 pts.wt. to 1 pt.wt. of the toner.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic charge developer containing a toner and a carrier.
The present invention relates to an electrostatic charge image developer which has stable toner density and charge amount and can stably develop an electrostatic latent image with high quality.

[0002]

2. Description of the Related Art In a dry developing method, an electrostatic latent image formed on a photosensitive member by charging and exposure is developed with toner,
The developed toner image is transferred to a support such as transfer paper, and the toner image is fixed to the support by a heating roller and / or a pressure roller to visualize the electrostatic latent image. Then, after the toner image is transferred to the support, in order to clean the toner remaining on the photoconductor, the cleaning member scrapes off the toner remaining on the photoconductor to prepare for the next image forming process.

The toner is a resin particle having a particle diameter of 1 to 100 μm in which a colorant, and if necessary, a charge control agent and a toner property imparting agent such as magnetic particles are dispersed in a binder resin. Further, as the performance of the toner, it is required that the density and charge amount of the toner are stable, and that the electrostatic latent image can be stably developed at the optimum density and with less fog.

Further, in general, in order to increase the charging speed of the toner, a coat carrier having a coating layer containing a fluororesin as a main component is often used as a carrier. In the production of positively chargeable toner, a quaternary ammonium salt or a nigrosine dye is used as a charge control agent for the toner.

[0005]

However, an electrostatic image developer using a coated carrier having a coating layer containing a fluororesin as a main component as a carrier cannot be said to be sufficient in terms of the above-mentioned required performance. The improvement is desired.
The present invention has been made in view of the above circumstances, and an object thereof is to provide a stable toner density and charge amount, and to stabilize a negative polarity electrostatic latent image at an optimum density and high-quality image quality with less fog. An object is to provide an electrostatic image developer that can be developed.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to achieve the above object, and as a result, by using a toner containing a ketone resin having a specific structure as a binder resin, the above object can be easily achieved. The present invention has been completed based on the knowledge that it can be achieved. That is, the gist of the present invention is, in an electrostatic image developer containing a toner and a carrier, the toner contains the cyclohexanone ketone resin represented by the chemical formula [Chemical Formula 1] as a binder resin, and the carrier is The electrostatic charge image developer is a coated carrier having a coating layer containing a fluorine-based resin as a main component.

The present invention will be described in detail below. First, the toner used in the present invention will be described. The toner is constituted by dispersing a colorant, a charge control agent, and a toner property imparting agent such as magnetic particles, if necessary, in a binder resin. Further, in the present invention, it is necessary that the toner contains the cyclohexanone type ketone resin represented by the chemical formula [Formula 1] as a binder resin. The degree of polymerization (n) in the above chemical formula [Chemical Formula 1] is usually about 1 to 10, but a cyclohexanone ketone resin having a softening point in the range of 70 to 150 ° C. is particularly preferable.

Cyclohexanone type ketone resins are usually
Used with other binder resins. As the other binder resin, various binder resins used in known toners can be used without limitation. Specifically, polystyrene resin, styrene acrylic resin, styrene-butadiene resin such as styrene-butadiene resin and various polyester resins, epoxy resin, phenol resin, coumarone resin, xylene resin, chlorinated paraffin resin, vinyl chloride resin, Examples include polyolefin resins.

The proportion of the cyclohexanone type ketone resin in the total binder resin is properly selected from the range of usually 10 to 80% by weight, preferably 15 to 50% by weight. When the proportion of the cyclohexanone type ketone resin is less than 10% by weight, the effect of the present invention obtained by using the resin is not sufficient, and when it exceeds 80% by weight, the toner is excessively pulverized.

As the colorant, various colorants used in known toners can be used without limitation.
Specific examples thereof include carbon black, nigrosine, benzidine yellow, quinacridone, rhodamine B, and phthalocyanine blue. The proportion of the colorant used is usually 0.1 to 30 parts by weight, preferably 0.5 to 10 parts by weight, per 100 parts by weight of the binder resin.

The charge control of the toner may be performed by the binder resin or the colorant itself, but it is preferable to use the charge control agent. Examples of the positive charge control agent include quaternary ammonium salts, nigrosine dyes, triphenylmethane dyes, styrene-aminoacrylate copolymers and polyamine resins, and examples of the negative charge control agent include metal chelates, Examples thereof include alloy dyes and metal salts of alkylsalicylic acid. In the present invention, it is particularly preferable to use a quaternary ammonium salt or a nigrosine dye.

The charge control agent may be mixed and added to the binder resin, or may be used by being attached to the surface of the toner particles. The amount of the charge control agent used is determined in consideration of the chargeability of the binder resin, the toner production method including the amount of the colorant added and the dispersion method, and the chargeability of other additives. Usually, the range of 0.1 to 10 parts by weight is suitable per 100 parts by weight of the binder resin.

In the present invention, various toner property imparting agents can be used. For example, polyethylene wax and polypropylene wax are used to prevent offset, and solid electrolytes, polymer electrolytes, charge transfer complexes, and metal oxides such as tin oxide are used to control the electrical properties of the toner. Conductors, others, semiconductors, and ferroelectrics are used. Further, in order to adjust the thermal characteristics, physical characteristics, etc. of the toner, various plasticizers and release agents are used, and in order to improve the fluidity and aggregation resistance of the toner,
Titania, alumina, silica, etc. are used. These toner property imparting agents are usually used in the range of 0.1 to 10 parts by weight per 100 parts by weight of the toner.

Further, in the present invention, in addition to the above-mentioned toner property imparting agent, a fine powder of a magnetic material may be contained in the toner according to the necessity of the developing mechanism. Examples of the magnetic material include ferrite and magnetite, as well as alloys or compounds containing ferromagnetic elements such as iron, cobalt and nickel. Further, an alloy which does not contain a ferromagnetic element but exhibits ferromagnetism by an appropriate heat treatment, for example, Mn-C.
Examples thereof include so-called Heusler alloys containing manganese and copper such as u-Al and Mn-Cu-Sn, or metal oxides such as chromium dioxide.

The above magnetic material has an average particle size of 0.3 to 30 μm.
It is used in a particle size of m and is usually used by being uniformly dispersed in a binder resin. The amount of the magnetic material used is usually 20 to 70 parts by weight, preferably 40 to 70 parts by weight, per 100 parts by weight of the binder resin.

The electrostatic image developing toner of the present invention can be manufactured, for example, by the following general manufacturing method. First, a binder resin, a colorant, and a charge control agent used if necessary are uniformly dispersed and mixed. The dispersion and mixing can be performed using a ball mill, a V-type mixer, an S-type mixer, a Henschel mixer, or the like. Then, the mixture is melt-kneaded with a twin-screw extruder, a twin-arm kneader, a pressure kneader, etc., and then cooled, and a hammer mill, a jet mill,
Grind with a crusher such as a ball mill. Then, the obtained powder is classified by a wind classifier or the like to obtain a toner. The particle diameter of the toner is 1 to 00 μm.

Next, the carrier used in the present invention will be described. The coated carrier is formed by coating the surface of the magnetic core particles with a resin. And in the present invention,
It is necessary for the coated carrier to have a coating layer containing a fluorine-based resin as a main component.

As the magnetic material core particles, various magnetic materials used in known coated carriers can be used without limitation. Specifically, ferrite, magnetite, iron, cobalt, nickel and other metals, Mn-C
Examples thereof include alloys such as u-Al and Mn-Cu-Sn, and metal oxides such as chromium dioxide.

The fluorine-based resin is not particularly limited, but vinylidene fluoride-based resins such as polyvinylidene fluoride, polytetrafluoroethylene, vinylidene fluoride-trifluoropropylene copolymer, vinylidene fluoride-hexafluoropropylene copolymer and the like. Copolymers are preferably used.

The above-mentioned coated carrier is produced, for example, by a method such as a flow coater method or a spray dryer method, in which a magnetic core particle is coated with a coating resin dissolved in a suitable solvent and dried. The film thickness of the resin coat layer is usually set in the range of 0.05 to 3 μm.

The electrostatic image developer of the present invention contains the above-mentioned toner and carrier. The amount of the carrier used is preferably selected from the range of 10 to 100 parts by weight per 1 part by weight of the toner.

[0022]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the following examples unless it exceeds the gist thereof. In addition, "part" in an Example represents a "weight part."

Example 1 Crosslinked styrene acrylic resin (divinylbenzene (crosslinking agent) / styrene / n-butyl acrylate copolymer) 8
0 parts, cyclohexanone type ketone resin (Hitachi Chemical Co., Ltd.)
"Hirac 110H") 20 parts, polypropylene wax ("Viscole 550P" manufactured by Sanyo Kasei Co., Ltd.) 3
Section, carbon black ("# 30" manufactured by Mitsubishi Kasei Co., Ltd.,
6 parts by weight (hereinafter the same) and 2.0 parts by weight of a nigrosine dye (“Bontron N-04” manufactured by Orient Chemical Co., Ltd.) were dispersed and mixed, and then melt-kneaded using a twin-screw extruder. After cooling, it was coarsely pulverized by a hammer mill and then finely pulverized by a supersonic jet mill pulverizer. The obtained powder was classified by an air classifier to obtain a toner having a mean diameter of 10.3 μm. The above toner was mixed with a polyvinylidene fluoride resin-coated ferrite carrier to obtain a developer having a toner concentration of 4% by weight.

Example 2 Non-crosslinked styrene acrylic resin (styrene / n-butyl acrylate / methyl methacrylate copolymer) 70
Part, cyclohexanone-based ketone resin (Arakawa Chemical Co., Ltd. "K-90") 30 parts, polypropylene wax ("Viscor 550P") 3 parts, carbon black 6 parts, 4
-Grade ammonium salt (Orient Bond Chemical's "Bontron P-
51 "), 2.0 parts by weight, and then the same operation as in Example 1 to obtain a toner having a mean particle diameter of 10.3 μm. The above toner was mixed with a polyvinylidene fluoride-trifluoroethylene copolymer-coated ferrite carrier to obtain a developer having a toner concentration of 4% by weight.

Example 3 70 parts of crosslinked polyester resin (polycondensation product of ethylene oxide adduct of bisphenol A and dimethyl phthalate and using trimellitic acid as a crosslinking agent), cyclohexanone type ketone resin (manufactured by Arakawa Chemical Co., Ltd. K-211 ") 3
0 parts, polypropylene wax ("Viscor 550
P) 3 parts, carbon black 6 parts, and nigrosine dye (“Bontron N-04”) 2.0 parts by weight are mixed, and the same procedure as in Example 1 is followed to obtain a flat particle diameter of 10.3 μm.
m toner was obtained. The above toner was mixed with a polyvinylidene fluoride resin-coated ferrite carrier to obtain a developer having a toner concentration of 4% by weight.

Comparative Example 1 100 parts of the same cross-linked styrene acrylic resin as used in Example 1, polypropylene wax ("Viscole 5"
50P ") 3 parts, carbon black 6 parts, and Nigrosine dye (" Bontron N-04 ") 2.0 parts by weight are mixed, and the same procedure as in Example 1 is followed to obtain a flat particle diameter of 10.3μ.
m toner was obtained. The above toner was mixed with a polyvinylidene fluoride resin-coated ferrite carrier to obtain a developer having a toner concentration of 4% by weight.

Comparative Example 2 100 parts of the same non-crosslinked styrene acrylic resin as used in Example 2, 3 parts of polypropylene wax ("Viscor 550P"), 6 parts of carbon black, quaternary ammonium salt ("Bontron P-51" )) After mixing 2.0 parts by weight, by the same operation as in Example 1, the average particle diameter 1
A toner of 0.3 μm was obtained. The above toner was mixed with a polyvinylidene fluoride-trifluoroethylene copolymer-coated ferrite carrier to obtain a developer having a toner concentration of 4% by weight.

Comparative Example 3 Crosslinked polyester resin 1 similar to that used in Example 3
00 parts, polypropylene wax ("Viscor 550
P) 3 parts, carbon black 6 parts, and nigrosine dye (“Bontron N-04”) 2.0 parts by weight are mixed, and the same procedure as in Example 1 is followed to obtain a flat particle diameter of 10.3 μm.
m toner was obtained. The above toner was mixed with a polyvinylidene fluoride resin-coated ferrite carrier to obtain a developer having a toner concentration of 4% by weight.

Using each of the above developers, a commercial copying machine equipped with an OPC photoconductor is used to age up to 100,000 sheets, and the toner density, toner charge amount, image density (I
D), fog was measured for each number of sheets, and the results are shown in Tables 1-6. The measurement was performed by the following method. Toner charge: Measured by blow-off method Image density: Measured by reflection densitometer Fog: Measured by whiteness meter

[0030]

[Table 1] (Developer of Example 1)Number of copies Toner density (%) Toner charge amount (μc / g) I / D fog Initial 3.9 15.6 1.41 0.43 1 (10,000 sheets) 3.9 15.9 1.42 0.39 5 (10,000 sheets) 3.8 15.4 1.40 0.39 10 (10,000 sheets) 3.9 15.3 1.40 0.39

[0031]

(Table 2) (Developer of Example 2)Number of copies Toner density (%) Toner charge amount (μc / g) ID fog Initial 3.9 16.0 1.42 0.50 1 (10,000 sheets) 3.9 15.9 1.41 0.43 5 (10,000 sheets) 3.9 16.3 1.40 0.40 10 (10,000 sheets) 3.8 16.5 1.40 0.40

[0032]

(Table 3) (Developer of Example 3)Number of copies Toner density (%) Toner charge amount (μc / g) I / D fog Initial 3.8 15.4 1.41 0.41 1 (10,000 sheets) 3.9 15.6 1.39 0.41 5 (10,000 sheets) 4.0 15.0 1.40 0.45 10 (10,000 sheets) 3.9 15.3 1.41 0.44

[0033]

[Table 4] (Developer of Comparative Example 1)Number of copies Toner density (%) Toner charge amount (μc / g) I / D fog Initial 3.9 18.3 1.41 0.60 1 (10,000 sheets) 3.6 21.3 1.32 0.61 5 (10,000 sheets) 3.5 26.7 1.15 0.63 10 (10,000 sheets) 3.1 30.1 1.00 0.68

[0034]

[Table 5] (Developer of Comparative Example 2)Number of copies Toner density (%) Toner charge amount (μc / g) I / D fog Initial 3.8 16.4 1.42 0.42 1 (10,000 sheets) 3.2 24.2 1.10 0.60 5 (10,000 sheets) 3.3 28.0 1.05 0.54 10 (10,000 sheets) 3.3 33.1 0.90 0.58

[0035]

[Table 6] (Developer of Comparative Example 3)Number of copies Toner density (%) Toner charge amount (μc / g) I / D fog Initial 3.9 15.8 1.40 0.56 1 (10,000 sheets) 3.6 12.0 1.40 0.70 5 (10,000 sheets) 3.4 9.8 1.45 1.12 10 (10,000 sheets) 3.2 6.5 1.45 1.28

[0036]

According to the present invention described above, there is provided an electrostatic charge image developer which has stable toner density and charge amount and can stably develop an electrostatic latent image with high quality. Therefore, the value of the present invention is great.

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Claims (2)

[Claims] 1. An electrostatic image developer containing a toner and a carrier, wherein the toner contains a cyclohexanone ketone resin represented by the following chemical formula [Chemical Formula 1] as a binder resin, and the carrier contains a fluorine resin as a main component. An electrostatic image developer, which is a coated carrier having a coating layer of [Chemical 1] 2. The electrostatic image developer according to claim 1, wherein the toner contains a quaternary ammonium salt or a nigrosine dye as a charge control agent.