JP3112084B2 - Negatively chargeable cyan toner for electrophotography - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a negatively chargeable cyan toner for electrophotography used for color electrophotography.

2. Description of the Related Art As a color toner for electrophotography, a toner in which various dyes and pigments are dispersed in a binder resin is widely used.
Among these color toners, a phthalocyanine-based organic pigment is generally used as a colorant for a cyan toner for electrophotography. The phthalocyanine-based organic pigment is most suitable for expressing cyan. In other words, L * a
L * = 40 to 60, a * = 0 when represented by * b * coloring system
It means that it is difficult to express a color of -20, b * =-40 to -60 with a colorant other than the phthalocyanine organic pigment. Especially among phthalocyanine organic pigments
Pigments classified as CI Pigment Blue 15-3 are most suitable in terms of color.

However, in the above-described conventional configuration, the phthalocyanine-based blue pigment tends to be essentially positively charged. Therefore, when the phthalocyanine-based blue pigment is used as it is for the negatively-chargeable toner, the oppositely charged toner, that is, the positively-charged toner, There is a problem that a charged toner is easily generated, the charge amount of the entire negatively charged toner is reduced, the fog density is increased, and the printing quality is poor.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a negatively chargeable toner for electrophotography which prevents generation of a reversely charged toner, that is, a positively charged toner, has a low fog density, and has good print quality. .

Means for Solving the Problems In order to achieve this object, there is provided a negatively chargeable cyan toner for electrophotography in which the surface of a phthalocyanine-based blue organic pigment is coated with fine powder of ethylene tetrafluoride resin. The particle size of the fine powder of the tetrafluoroethylene resin was set to 0.1 to 0.5 μm. The weight ratio of the phthalocyanine-based blue organic pigment to the ethylene tetrafluoride resin fine powder was set to 100: 3 to 100: 7.

Action With this configuration, the phthalocyanine-based blue organic pigment having positive chargeability can be electrically neutralized or charged to the negative side.

Examples Hereinafter, the present invention will be described more specifically with reference to Examples.
Note that the present invention is not limited to these examples. Hereinafter, all the contents of the number of parts in the composition are parts by weight.

Example 1-Binder resin 100 parts of styrene-acrylate resin (trade name: Hymer TBL-500 manufactured by Sanyo Chemical Co., Ltd.)-Wax Polypropylene wax 4 parts (trade name: Viscol 550-P manufactured by Sanyo Chemical Co., Ltd.)-Charging agent ( Product name Kayacharge N-3 Nippon Kayaku Co., Ltd.) Coloring agent CI Pigment Blue 15-3 3 parts [Surface coated with 5% fine powder of ethylene tetrafluoride resin based on the above pigment. (Product name CI Pigment Blue 15-3: KET Blue
-111 Product name, manufactured by Dainippon Ink Co., Ltd. Low molecular weight ethylene tetrafluoride resin: Lubron L-2 manufactured by Daikin Industries, Ltd.) The above materials are uniformly dispersed with a Henschel mixer, and the dispersion is melt-kneaded with a twin-screw extruder or the like. After cooling, the mixture was finely pulverized with a jet mill or the like, and a classified product having an average particle size of 11 μm was obtained using a classifier. 0.3% hydrophobic silica (trade name: R-972)
Nippon Aerosil Co., Ltd.) was externally added with a Henschel mixer to obtain a cyan toner of the present invention.

Example 2 A cyan toner was obtained in the same manner as in Example 1 except that the binder resin in Example 1 was changed to the following.

-Binder resin 100 parts of saturated polyester resin (trade name: Polyester HP-300, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) Example 3 The same as Example 1 except that the binder resin in Example 1 was changed to the following. Thus, a cyan toner was obtained.

-Binder resin 100 parts of styrene-acrylic acid resin (trade name: ZSR-1008 manufactured by Fujikura Kasei Co., Ltd.) Example 4 Except that the pigment in Example 1 was changed to the following:
A cyan toner was obtained in the same manner as in Example 1.

-Coloring agent C.I. Pigment Blue 15-3 3 parts (trade name: KET Blue-104, manufactured by Dainippon Ink) The surface treatment of the pigment is the same as in Example 1.

Example 5 A cyan toner was obtained in the same manner as in Example 1 except that the fine powder of the tetrafluoroethylene resin in Example 1 was changed to the following.

Colorant CI Pigment Blue 15-3 3 parts The amount of pigment and fine powder of ethylene tetrafluoride resin are the same as in Example 1.

(Product name: low molecular weight tetrafluoroethylene resin: Lubron L-5 manufactured by Daikin Industries, Ltd.) Comparative Examples 1 to 4 Except that the pigments in Examples 1 to 4 were not surface-coated with fine powder of ethylene tetrafluoride resin. A cyan toner was obtained in the same manner as in Examples 1 to 4.

A ferrite carrier (trade name: FL-150, manufactured by Powder Tech) is used for each of the toners formed as described above.
To obtain a developer. Using these developers, continuous printing was performed on 20,000 sheets using a laser printer (trade name: KX-P4450, manufactured by Matsushita Electric Industrial Co., Ltd.), and the characteristics of image density and fog density were summarized in Tables 1 and 2.

As can be seen from Table 1, the image density hardly changes between Examples 1 to 5 and Comparative Examples 1 to 4 even after printing 20,000 sheets. Therefore, it can be seen that the phthalocyanine-based blue organic pigment in which the surface of the phthalocyanine blue organic pigment is coated with the fine powder of ethylene tetrafluoride has the same image density as the conventional one. Further, as can be seen from Table 2, the fog density increased only about 0.1 in Examples 1 to 5 after printing 20,000 sheets, but increased about 1.0 in Comparative Examples 1 to 4. Therefore, in Examples 1 to 5, the oppositely-charged toner, that is, the positively-charged toner is hardly generated, and the charge amount is larger than that in Comparative Examples 1 to 4, so that the fog density is low and the print quality is better than before.

As described above, in the present embodiment, the surface of the phthalocyanine-based blue organic pigment was coated with fine powder of ethylene tetrafluoride resin, thereby preventing the generation of the positively charged toner.
Since the charge amount can be increased, the fog density can be reduced, and the printing quality can be improved.

In addition, as a tetrafluoroethylene resin fine powder, 0.1 to 0.5
A fine white powder of μm is preferred. Also CI Pigment Blue
Examples of pigments belonging to 15-3 include cyanine blue 4938 (Dainichi Seika), Monastral Blue BG (ICI), Hostaperm Blue BG (Hoechst), Sumika Print Cyanine Blue GN-0-3 (Sumitomo Chemical), Lionol Blue GLA (Toyo Ink), KET Blue 104, KET Blue 111
(Dainippon Ink).

The method of coating the surface of the pigment with the ethylene tetrafluoride resin fine powder is as follows: a Henschel mixer or a super mixer is provided with a pigment: ethylene tetrafluoride = 100: 0.1 to 100: 10 weight ratio, and more preferably 100: 3 to 100: 100. : 7 and performed by high-speed rotation.

The amount of the pigment used in the present invention as a toner composition is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the resin. More preferably, it is 2.0 to 4.0 parts by weight. If the amount is less than 0.1 part by weight, it is not possible to obtain a sufficient image density because color developing properties cannot be obtained. If the amount is more than 10 parts by weight, the dispersion of the pigment in the resin is reduced, and the charging characteristics are deteriorated.

The charge control of the toner may be performed by the binder resin or the pigment itself, but if necessary, a charge control agent that does not cause a problem in color reproduction may be used together. For example, metal chelates such as a gold-containing dye, an acidic or electron-withdrawing organic substance, and the like can be used.

In addition, as the binder resin of the present invention, all known resins can be used. For example, polystyrene, poly-α-methylstyrene, chloropolystyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer Copolymer, styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl acrylate copolymer, styrene-acrylonitrile-acrylic acid ester copolymer Styrene-based resins (homopolymers or copolymers containing styrene or styrene substituents), epoxy resins, urethane-modified epoxy resins, silicone-modified epoxy resins, polyester resins, vinyl chloride resins, styrene-vinyl acetate copolymers, Rosin-modified maleic resin, Fe Neal resin, polyethylene, polypropylene, ionomer resin, polyurethane resin, silicone resin, ketone resin, ethylene-ethyl acrylate copolymer, xylene resin, polyvinyl butyral resin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, Etc. can be used alone or in combination.

Particularly preferred in this case are styrene-acrylate resin, styrene-methacrylate resin, and polyester resin.

When the present developer is used as a two-component toner, known carriers can be used as the carrier. For example, surface oxidized or unoxidized iron or iron and nickel,
Metals such as copper, zinc, cobalt, manganese, chromium, and rare earths and alloys thereof, or oxides and ferrites can be used. Those whose surfaces are coated with various resins or the like can also be used. If necessary, a fluidity modifier such as colloidal silica may be added to the toner in an amount of 0.01%.
6.06.00% by weight, more preferably 0.1 to 1.0% by weight.

The present invention provides a negatively chargeable cyan toner for electrophotography in which the surface of a phthalocyanine-based blue organic pigment is coated with fine powder of ethylene tetrafluoride resin, and the particle size of the fine powder of ethylene tetrafluoride resin is also provided. 0.1 to 0.5 μm, and by setting the weight ratio of the phthalocyanine blue organic pigment and the tetrafluoroethylene resin fine powder to 100: 3 to 100: 7, a phthalocyanine blue organic pigment having a positive charge property Since it can be electrically neutralized or charged to the negative side, the charge amount can be increased, and the fog density can be reduced, so that the print quality can be improved.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Daimitsu Shimazaki 1006 Kazuma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. In-company (56) References JP-A-57-186758 (JP, A)

Claims (3)

(57) [Claims] 1. A negatively chargeable cyan toner for electrophotography, comprising a phthalocyanine-based blue organic pigment whose surface is coated with fine powder of ethylene tetrafluoride resin and a binder resin. 2. The fine powder of ethylene tetrafluoride resin having a particle size of 0.1
2. The negatively chargeable cyan toner for electrophotography according to claim 1, wherein the thickness of the toner is from 0.5 to 0.5 [mu] m. 3. The negatively chargeable cyan toner for electrophotography according to claim 1, wherein the weight ratio of the phthalocyanine-based blue organic pigment to the fine powder of ethylene tetrafluoride resin is 100: 3 to 100: 7. .