JP2805975B2 - Negatively chargeable cyan toner for color electrophotography - Google Patents

Description

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

2. Description of the Related Art Toners in which various dyes and pigments are dispersed in a binder resin are widely used as color electrophotographic toners.
Among these color toners, as a cyan toner for electrophotography, those using a phthalocyanine organic pigment are mainly used. This is because the phthalocyanine-based organic pigment has a clear blue color and is excellent in color reproducibility in a single color copy and a multicolor copy. However, phthalocyanine-based organic pigments themselves have a strong positive charge,
Use with a negatively chargeable toner tends to cause deterioration of copy image quality.

Problems to be Solved by the Invention Phthalocyanine inherently has a tendency to be positively charged, and when used as a negatively chargeable toner, there is a disadvantage that the development characteristics are easily deteriorated economically.

Accordingly, the present invention solves the above-mentioned disadvantages of the conventional negatively chargeable cyan toner, and provides excellent chargeability, deterioration resistance with time, and moisture resistance.

Means for Solving the Problems The technical means of the present invention for solving the above problems is to coat the surface of a phthalocyanine-based blue organic pigment with negatively-chargeable hydrophobic silica.

As negatively charged hydrophobic silica, 5 to 100 mm, specific surface area 8
Fine powder of silicon dioxide of 0 to 700 m ² / g is preferred. Aerosil 130,200,300,380, O × 50, TT600, MO ×
80, MO × 170, COK84R972, R812 (all manufactured by Nippon Aerosil Co., Ltd.).

Pigments belonging to CI Pigment Blue 15-3 include cyanine blue 4938 (manufactured by Dainichi Seika Co., Ltd.), Monastral Blue BG (manufactured by ICI), Hostaperm Blue BG (manufactured by Nippon Hoechst) , Sumika Print Cyanine Blue GN-0-3 (Sumitomo Chemical Co., Ltd.), Lionol Blue GLA (Toyo Ink Co., Ltd.), KET Blue
104, KET Blue 111 (manufactured by Dainippon Ink Co., Ltd.) and the like. The method of coating the surface of the pigment with silica is as follows: Henschel mixer or super mixer, pigment: silica = 100: 0.1
The mixture is charged at a weight ratio of 100100: 10, more preferably 100: 3 to 100: 7, and the high-speed rotation is performed.

The amount of the pigment used in the present invention is desirably 0.1 to 10.0 parts by weight based on 100 parts by weight of the resin. More preferably, it is 2.0 to 4.0 parts by weight. When the amount is less than 0.1 part by weight, it is not possible to obtain a sufficient image density because color development characteristics cannot be obtained, and 10
If it is more than parts by weight, the dispersion of the pigment in the resin is reduced,
The charging characteristics deteriorate.

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

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, styrene-
Styrenes such as maleic acid copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl acrylate copolymer, styrene-acrylonitrile-acrylic acid ester copolymer Resin (homopolymer or copolymer containing styrene or styrene substituent), epoxy resin, urethane-modified, epoxy resin, silicone-modified epoxy resin, polyester resin, vinyl chloride resin, styrene-vinyl acetate copolymer, rosin-modified maleic Acid resin, phenyl 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-
There are 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. In addition, if necessary, a fluidity modifier such as colloidal silica may be used in an amount of 0.01 to Honor.
6.06.00% by weight (more preferably 0.1 to 1.0% by weight) may be added.

Operation The operation of this technical means is as follows. That is,
By coating the surface of the pigment with negatively chargeable hydrophobic silica, the positive charge of the pigment itself is neutralized, or the pigment is charged to the negative side. Then, the polarity is matched with the polarity of the toner to prevent the generation of the oppositely charged toner.

Further, since silica is hydrophobic, it has good moisture resistance even under high humidity conditions. As a result, it has excellent charging characteristics and deterioration resistance with time.

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

Example 1. 100 parts of styrene-acrylate resin (trade name: Hymer TBL-500, manufactured by Sanyo Chemical Co., Ltd.) 4 parts of polypropylene wax (trade name: Piscol 500-P, manufactured by Sanyo Chemical Co., Ltd.)-Charge control agent 4 Department (Kayacharge N-3, manufactured by Nippon Kayaku Co., Ltd.) ・ CI Pigment Blue 15-3 3 The above-mentioned materials were uniformly dispersed with a Henschel mixer, the dispersion was melt-kneaded with a twin-screw extruder or the like, cooled, then finely pulverized with a jet mill or the like, and a classified product having an average particle size of 11 μm was obtained with a classifier. 0.3% hydrophobic silica (trade name R972,
Nippon Aerosil Co., Ltd.) with a Henschel mixer,
A cyan toner of the present invention was obtained. This toner was mixed with a ferrite carrier (FL-150, manufactured by Nippon Iron Powder Co., Ltd.) to obtain a developer. Using this developer, a laser printer (trade name)
(KX-P4450, manufactured by Matsushita Electric Industrial Co., Ltd.) to print 20,000 sheets continuously. The image quality of the obtained print was good over 1 to 20,000 sheets.

Example 2. ・ Styrene-acrylate resin 100 parts (Himer TBL-1000 manufactured by Sanyo Chemical Co., Ltd.) ・ Polypropylene wax 4 parts (Viscol 500-P manufactured by Sanyo Chemical Co., Ltd.) ・ Charge control agent 4 parts ( Kayacharge N-3 Nippon Kayaku Co., Ltd.) 3 parts of CI Pigment Blue 15-3 The above pigment is surface-coated with 3% negatively chargeable hydrophobic silica.

A cyan toner was obtained in the same manner as in Example 1. Further, the same printing test was performed. This was also good printing quality for 1 to 20,000 sheets.

Comparative Example 1. ・ Styrene-acrylate resin 100 parts (Himer TB-1000 manufactured by Sanyo Chemical Co., Ltd.) ・ Polypropylene wax 4 parts (Viscol 550-P manufactured by Sanyo Chemical Co., Ltd.) ・ Charge controlling agent 4 parts ( Kayacharge N-3 Nippon Kayaku Co., Ltd.) ・ CI Pigment Blue 15-3 3 parts (KET Blue-104 Dainippon Ink Co., Ltd.) A cyan toner was obtained in the same manner as in Example 1. . Also,
The same printing test was performed. Although the print quality was good up to about 7,000 sheets, the stain on the non-image area became noticeable from about 13,000 sheets, and the print quality became unusable after 20,000 sheets. This is considered to be due to the fact that the pigment has the opposite chargeability to the toner. That is, the proportion of the oppositely charged toner increases with the printing, which is considered to be the cause of the non-image portion stain.

Comparative Example 2. 100 parts of polyester resin (Hymer ES-508 manufactured by Sanyo Chemical Co., Ltd.)-4 parts of polypropylene wax (Viscol 550-P manufactured by Sanyo Chemical Co., Ltd.)-4 parts of charge control agent (Kayacharge N-3) CI Pigment Blue 15-3, 3 parts (KET Blue-111, Dainippon Ink Co., Ltd.) A cyan toner was obtained in the same manner as in Example 1. Also,
The same printing test was performed. Although the print quality was good up to about 5,000 prints, the stain on the non-image area became noticeable from about 10,000 prints, and the print quality was unusable after 20,000 prints. This is also considered to be due to an increase in the oppositely charged toner.

Effect of the Invention As described above, by using the cyan toner of the present invention, it is possible to suppress the generation of the reversely charged toner and obtain a negatively charged toner having excellent charging characteristics, aging resistance and moisture resistance. it can. Therefore, a cyan image with good print quality can be provided for a long time.

When the pigment of the present invention is used, it can be widely used as a negatively chargeable one-component cyan toner.

Continuation of the front page (72) Inventor Toshikazu Ito 1006 Kazuma Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (56) References JP-A-60-209742 (JP, A) JP-A-61-80262 ( JP, A) JP-A-62-280755 (JP, A) JP-A-1-159666 (JP, A) JP-A-2-196247 (JP, A) JP-A-3-276163 (JP, A) (58) ) Surveyed field (Int.Cl. ⁶ , DB name) G03G 9/09

Claims (3)

(57) [Claims] 1. A negatively chargeable color electrophotographic negative color pigment comprising a colorant and a binder resin as main components, wherein the colorant is a phthalocyanine blue organic pigment whose surface is coated with negatively chargeable hydrophobic silica. Cyan toner. 2. The pigment is CI Pigment Blue 15-3.
The toner according to claim 1, which is classified as: 3. The pigment is 0.5 to 10% by weight based on the binder resin.
2. The toner according to claim 1, which is contained at a ratio of: