JP2002365851A - Color toner for electrophotography - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color toner for electrophotography with which images of high quality and high color saturation can be continuously obtained. SOLUTION: In the color toner for electrophotography containing binding resin and colorants, Indanthrone type blue pigment is contained as colorant 0.1 to 15 pts.wt. against binding resin 100 pts.wt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color toner for electrophotography used for developing an electrostatic latent image formed in electrophotography, electrostatic recording, electrostatic printing, and the like.

[0002]

2. Description of the Related Art Conventionally, toners containing a copper phthalocyanine pigment as a blue colorant have been widely used. However, since the hue of such a toner is located between a cyan color and a blue color, it has a reddish blue color. No toner can be obtained.

[0003] Further, since the copper phthalocyanine pigment has a strong crystallinity, it is easily dispersed in a binder resin, and it is difficult to stabilize the charge amount during long-term use. Japanese Patent Application Laid-Open No. 5-88410 discloses a combination of a copper phthalocyanine pigment and an inorganic pigment. However, since the inorganic pigment has a large particle diameter, the inorganic pigment is easily detached from the toner surface and is continuously stable. It is difficult to obtain images.
Further, the mixture of pigments having different hues leads to a decrease in saturation.

On the other hand, in a high-speed machine having a linear velocity of 370 mm / sec or more, an inorganic photosensitive member is used from the viewpoint of durability. However, when a toner containing an organic pigment containing copper phthalocyanine is used, the photosensitive member is not used. Crystallization makes it difficult to obtain a continuously stable image.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a color toner for electrophotography capable of continuously obtaining high quality and high chroma images.

[0006]

SUMMARY OF THE INVENTION The present invention relates to an electrophotographic color toner containing a binder resin and a colorant, wherein an indanthrone blue pigment is used as a colorant in 100 parts by weight of the binder resin. The present invention relates to an electrophotographic color toner containing 0.1 to 15 parts by weight of the toner.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is greatly characterized in that an indanthrone blue pigment is contained as a colorant. Indantron blue pigments
It has high compatibility with the polyester contained as the binder resin and is finely dispersed in the toner, and not only exhibits excellent color saturation as a color toner, but also can provide a continuously stable image. . Further, since the indanthrone-based blue pigment has a different hue from the copper phthalocyanine-based pigment, the toner of the present invention has a unique reddish blue hue that has not been obtained conventionally.

[0008] The indanthrone blue pigment may be contained alone or as a mixture of two or more.
At least one species is C.I. I. Pigment Blue 60 is preferred. Indantron blue pigments are available from Host
perm Blue RL01 "(manufactured by Clariant,
C. I. Pigment Blue 60).

The content of the indanthrone blue pigment is as follows:
From the viewpoints of colorability and chroma, the amount is 0.1 to 15 parts by weight, preferably 1 to 10 parts by weight, based on 100 parts by weight of the binder resin.

The binder resin in the present invention preferably contains polyester as a main component. The content of the polyester is preferably 50 to 100% by weight in the binder resin,
-100% by weight is more preferable, and 100% by weight is particularly preferable. Note that the binder resin may appropriately contain a resin such as a styrene-acrylic resin, an epoxy resin, a polycarbonate, or a polyurethane.

As a raw material monomer for polyester, 2
Polyhydric alcohols having a valency of 2 or more and polycarboxylic acids having a valency of 2 or more can be used.

Examples of the dihydric polyhydric alcohol include polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane and polyoxyethylene (2.2) -2,2-bis (4-hydroxyphenyl). Examples include alkylene oxide adducts of bisphenol A such as propane, ethylene glycol, 1,2-propylene glycol, 1,4-butanediol, neopentyl glycol, polyethylene glycol, polypropylene glycol, bisphenol A, and hydrogenated bisphenol A.

Examples of the trihydric or higher polyhydric alcohol include sorbitol, pentaerythritol, glycerol, trimethylolpropane and the like.

Further, as the divalent carboxylic acid compound,
For example, maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, adipic acid, dicarboxylic acids such as succinic acid, tetrapropenyl succinic acid, n-dodecenyl succinic acid, isododecenyl succinic acid, n-dodecyl succinic acid, iso- Succinic acid substituted with an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms, such as octenyl succinic acid and isooctyl succinic acid, and anhydrides or lower alkyls of these acids (1 to 3 carbon atoms); ) Esters and the like.

Examples of the trivalent or higher polycarboxylic acid compound include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, pyromellitic acid and acid anhydrides thereof. And lower alkyl (C1-3) esters.

The polyester can be produced, for example, by subjecting an alcohol component, a carboxylic acid component, and the like to condensation polymerization at a temperature of 180 to 250 ° C. in an inert gas atmosphere, if necessary, using an esterification catalyst. it can.

The acid value of the polyester is preferably from 3 to 50 mgKOH / g, more preferably from 3 to 30 mgKOH / g, and the hydroxyl value is preferably from 5 to 60 mgKOH / g, from the viewpoints of pigment dispersibility and environmental stability.

The softening point of the polyester is preferably from 80 to 150 ° C, and the glass transition point is preferably from 50 to 80 ° C.

In the toner of the present invention, in addition to the binder resin and the colorant, a charge control agent, a release agent, a fluidity improver, a conductivity adjuster, a reinforcing pigment such as an extender, a fibrous substance, and the like, Additives such as an antioxidant, an antioxidant, and a cleaning improver may be appropriately contained.

The toner of the present invention is preferably a pulverized toner obtained by a kneading and pulverizing method. For example, after a binder resin, a colorant and the like are uniformly mixed by a mixer such as a ball mill, a closed kneader or a uniaxial or It can be manufactured by melt-kneading with a twin-screw extruder or the like, cooling, pulverizing, and classifying. The volume average particle diameter of the toner is preferably 3 to 15 μm. Further, a fluidity improver such as hydrophobic silica may be added to the surface of the toner as an external additive.

Since the color toner for electrophotography of the present invention uses a blue colorant containing no copper, it can be used in a high-speed machine having an inorganic photoreceptor and having a linear speed of 370 mm / sec or more. . When magnetic fine powder is contained, it is used alone as a developer, and when magnetic fine powder is not contained, it is used as a non-magnetic one-component developer or as a two-component developer by mixing with a carrier. obtain. Further, the color toner for electrophotography of the present invention can be used as a full color toner together with a yellow toner, a magenta toner and the like.

[0022]

[Examples] [Acid value and hydroxyl value] Measured according to the method of JIS K0070.

[Glass transition point] Differential scanning calorimeter "DSC"
210 "(manufactured by Seiko Denshi Kogyo KK) using a heating rate of 1
Measure at 0 ° C./min.

Resin Production Example 1 714 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene
(2.2) 663 g of 2,2-bis (4-hydroxyphenyl) propane, 518 g of isophthalic acid, 70 g of isooctenylsuccinic acid, 80 g of trimellitic acid and 2 g of dibutyltin oxide were stirred at 210 ° C. under a nitrogen atmosphere at 210 ° C. Until the temperature reached 130 ° C. to obtain a binder resin A. The acid value of the binder resin A was 18 mgKOH / g, the hydroxyl value was 35 mgKOH / g, and the glass transition point was 65 ° C.

Example 1 100 parts by weight of a binder resin A and a coloring agent "Hostperm"
Blue RL 01 ”(Clariant, C.I.
I. Pigment Blue 60) was sufficiently mixed with a Henschel mixer, melt-kneaded in a twin-screw extruder equipped with a barrel cooling device, cooled, and coarsely pulverized. afterwards,
The powder was pulverized and classified by a jet mill to obtain a powder having a volume average particle diameter of 9 μm. To 100 parts by weight of the obtained powder, 0.5 parts by weight of hydrophobic silica "Aerosil R-972" (manufactured by Nippon Aerosil Co., Ltd.) as an external additive was added, and mixed with a Henschel mixer to obtain a toner. Obtained.

Comparative Example 1 Instead of "Hostperm Blue RL 01", a copper phthalocyanine pigment "Cyanin Blue" was used.
A toner was obtained in the same manner as in Example 1, except that 5 parts by weight of "3008" (manufactured by Sanyo Dyeing Co., Ltd.) was used.

Comparative Example 2 Instead of "Hostperm Blue RL 01", a copper phthalocyanine pigment "Cyanin Blue" was used.
3008 "(manufactured by Sanyo Dyestuffs Co., Ltd.) 1 part by weight and navy blue" 67
A toner was obtained in the same manner as in Example 1, except that 4 parts by weight of "1 Conc T Navy Blue" (manufactured by Dainichi Seika Kogyo Co., Ltd.) was used.

Test Example 1 A V-type blender was used in which 3 parts by weight of each of the toners obtained in Example 1 and Comparative Examples 1 and 2 and 100 parts by weight of a styrene-methyl methacrylate resin-coated ferrite carrier (average particle diameter: 90 μm) were used. To prepare a developer.

The obtained developer is included in an electrophotographic recording apparatus (linear speed: 400 mm / sec) equipped with a selenium photoreceptor, and 100,000 sheets of printing at a printing rate of 4% are continuously performed, and 30,000 sheets are printed. The remaining toner charge amount and image density at the time of printing 50,000 sheets and 100,000 sheets were measured according to the following method, and the background fog of the non-image portion was visually evaluated according to the following evaluation criteria. Table 1 shows the results.

[Measurement of Charge Amount] The charge amount is measured by a blow-off method using a charge amount measuring device (Q / m meter, manufactured by Epping Corporation).

[Measurement of Image Density] The optical reflection density of a solid image is measured using a colorimeter “SPM50” (manufactured by GRETAG).

[Evaluation Criteria for Ground Fog] A: No ground fog is observed. ：: Ground covering is slightly recognized. Δ: Land fog is easily recognized. ×: Ground fogging is observed on the entire surface.

[0033]

[Table 1]

Test Example 2 Using the same apparatus as in Test Example 1, the image density was about 1.3 and 2.4.
A solid image having a cm width was obtained, and the hue was measured according to the following method. Table 2 shows the results.

[Measurement method of hue] Colorimeter "SPM50"
(GRETAG), measuring light D ₅₀ , viewing angle 2 °
Then, a ^* and b ^* are measured, and the saturation (C ^* ) is calculated from the following equation.
Is calculated.

[0036]

(Equation 1)

[0037]

[Table 2]

From the above results, since the indanthrone-based blue pigment is used as a colorant, the toner of Example 1 has a sufficient hue as a reddish blue toner.
The saturation also shows a sufficiently high value. In addition, the toner of Example 1 has a stable chargeability and continuously obtains a stable image, whereas the toner of Comparative Example 1 contains a copper phthalocyanine-based pigment, and thus has a high durability. You can see that it is missing. Further, from Comparative Example 2, it can be seen that even when a copper phthalocyanine-based pigment and an inorganic pigment are used in combination, the obtained image has low chroma and a stable image cannot be obtained continuously.

[0039]

According to the present invention, there is provided an electrophotographic color toner capable of continuously obtaining high quality and high chroma images.

Claims (3)

[Claims] An electrophotographic color toner containing a binder resin and a colorant, wherein an indanthrone blue pigment is used as a colorant in an amount of 0.1 to 15 parts by weight based on 100 parts by weight of the binder resin. A color toner for electrophotography containing a part of the toner. 2. The indanthrone blue pigment is C.I. I.
The color toner for electrophotography according to claim 1, which is Pigment Blue 60. 3. The color toner for electrophotography according to claim 1, wherein the main component of the binder resin is polyester.