JP2814096B2 - Magenta toner - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a magenta toner for electrophotography used in a full-color copying machine for developing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing and the like.

2. Description of the Related Art As a method of forming a visible image by developing an electric latent image with a developer, an electrostatic printing method, an electrophotographic method, and the like are conventionally well known. For example, in electrophotography, U.S. Pat.
No. 297,691, JP-B-42-23910, JP-B-43-
Various systems described in, for example, Japanese Patent No. 24748 are well known.
Generally, an electric latent image is formed on a photoconductor showing photoconductivity by various means using a photoconductive substance, and then the latent image is developed with a developer to obtain a visible image, or If necessary, a toner powder image is transferred to paper or the like, and then fixed by heating, pressurizing, or solvent vapor to obtain a visible image. In order to obtain a multicolor image of color, the original is exposed using a color separation filter, and the above process is repeated a plurality of times using a color developer such as yellow, magenta, and cyan, and the toner image is superimposed with the color image. Is what you do.

As the conventional magenta colorant for electrophotography, a dye or pigment is used alone. For example, Japanese Patent Publication No. 50-776,
-46951, JP-A-59-9906, JP-A-53-29132
As disclosed in JP-A-55-26574 and JP-A-58-118653, there are dyestuffs of xanthene type, quinacridone type, oxazine type, thioindico type and methine type.

A method containing three or more of these dyes and pigments is disclosed in
49-123333, JP-A-56-75660, JP-A-57
JP-A-130046, JP-A-59-100451, JP-A-59-100451
Although it is disclosed in Japanese Patent Application No. 219756 and the like, the spectral reflection characteristics and the hue have been improved, but it was not sufficiently satisfactory as a magenta toner.

 The conditions required for the electrophotographic magenta toner are as follows: 1) Spectral reflection characteristics are good.

2) The transparency of the toner is good, and the transparency is not reduced (the saturation is not reduced) by superimposition with the cyan toner and / or the yellow toner.

3) Excellent light fastness.

4) Dispersion of the binder resin and the coloring agent is good, and the coloring power is high.

5) Stable charging characteristics in various environments from low temperature and low humidity to high temperature and high humidity.

That is.

[Problems to be Solved by the Invention] An object of the present invention is to provide a magenta toner for electrophotography which satisfies all of the required conditions as described above.

Another object of the present invention is to provide a magenta toner that matches the functions required by a copying machine and does not cause significant side effects (for example, does not cause the surface of the silicone rubber fixing roller to stain and deteriorate).

Another object of the present invention is to provide a magenta toner which is less likely to be spent on a carrier surface even by repeated copying.

[Means and Actions for Solving the Problems] The present invention relates to a method of adding a quinacridone-based colorant and a colorant comprising a xanthene-based colorant represented by the following general formula (I) to 100 parts by weight of a binder resin. 2-20 by quantity
Magenta toner contained in parts by weight, and the addition ratio of the quinacridone colorant to the xanthene colorant (quinacridone colorant / xanthene colorant) is 4.5 / 0.
The present invention relates to a magenta toner characterized in that the fluidity modifier is added in an amount of 0.01 to 5% by weight based on the magenta toner.

General formula (I)[R in the general formula (I)₁~ R₆Is -H or C_nH_{2n + 1})
An alkyl group represented by the formula (n = 1 to 5) or C:_nH
_2n-1An alkenyl group represented by (n = 2 to 5)
R₇Is -H or C_nH_{2n + 1}) (N = 1-5)
Is an alkyl group represented by A Is SO_Three ^-, HCO_Three ^-, H_TwoPO_Four
^-Is an anion of In a xanthene-based colorant, R₇Is 1 to 4 carbon atoms
Is more preferred.

The quinacridone-based colorant is a high-grade colorant having a slightly reddish tint and excellent in light resistance and charge stability, but has unsuitable performance as a magenta toner when added alone. That is, with respect to the hue, the bluish portion has less reflection than the ideal magenta color and is reddish. The color tone also has disadvantages such as poor chroma and insufficient vividness, and therefore, when used alone, the quality of color reproducibility is insufficient. However, when it is used as a toner, it has favorable characteristics, such as being less spent on the carrier surface even after repeated copying.

On the other hand, a xanthene-based colorant is a colorant such as a rhodamine dye, and is a colorant that emits fluorescence and exhibits a clear bluish pink color. However, if a laked pigment of a xanthene dye as disclosed in JP-B-59-9906 is used alone, it cannot be used as a magenta color, and it is inferior in light resistance and fades in a short time. Therefore, the added amount cannot be increased. At present, full-color copiers are being used for general purposes.Copies are used for various purposes, and therefore, lightfastness is a very important item, and must be used after sufficient consideration of such properties of xanthene colorants. No.

As a conventional xanthene colorant, And the like.

Are preferred as magenta colorants because they all exhibit vivid bluish pink tones, and have a slight hygroscopic property because they are basic dyes, and have a charge amount in a high humidity environment. Tends to fall. Alternatively, they are oil-soluble, have excellent compatibility with resins, have good dispersion of colorants, and have very large coloring power. However, since it has good compatibility with silicone rubber used as a fixing roller, it may be dyed on the fixing roller and impair the releasability.

The anion of the basic dyes such as and in the present invention _{^{SO 3 -, HCO 3 -,}} H 2 PO 4 - The use of oxygen compounds such as, improved hygroscopicity and compatibility with the resin Excellent, furthermore, there is no roller dyeing, and deterioration of releasability can be prevented.

The present invention provides a magenta toner having good color tone and electrophotographic properties while complementing each other's disadvantages by adding colorants having these properties to each other. That is, the present invention provides a hue based on a bluish hue and a highly saturated xanthene colorant in combination with a bluish hue, in order to compensate for the reddish color and saturation, which are disadvantages of a quinacridone colorant. The object of the present invention is to provide a magenta toner which has high color saturation, excellent dispersibility in resin, light resistance, chargeability and transparency, and which is hardly contaminated by a silicone rubber roller for fixing and spent on a carrier surface.

The addition amount of the colorant of the present invention is determined by the type of the binder resin, the presence or absence of the additive used as needed, and the toner production method including the dispersion method, and is not limited uniquely. However, generally speaking, the total amount of the colorant is 2 to 20 parts by weight based on 100 parts by weight of the binder resin, and preferably 3 to 20 parts by weight.
15 parts by weight. Further, the addition ratio of the quinacridone colorant to the xanthene colorant (quinacridone colorant / xanthene colorant) is 4.5 / 0.5 to 6.0 / 1.0.

When the addition ratio of the xanthene-based coloring agent is increased so as to exceed 4.5 / 0.5, the light resistance is deteriorated, and the charge amount is reduced, thereby promoting scattering and fogging. Further, when the ratio is reduced to less than 6.0 / 1.0, hue and sharpness deteriorate.

The following compounds are typical examples of the quinacridone colorants.

Among them, CI Pigment Red 122 is particularly suitable as a colorant for magenta.

Further, specific examples of the dye represented by the general formula (I) used as a xanthene-based coloring agent are represented by structural formulas. For example (Structural example 1) (Structure example 2) (Structure example 3) (Structural example 4) (Structural example 5) (Structural example 6) (Structural example 7) (Structural example 8) (Structural example 9) (Structural example 10) And the like can be preferably used. Among them, the coloring agent shown in Structural Example 3 is particularly preferable.

The toner used in the present invention has a volume average particle size of 5 to 20 μm.
m, preferably 6 to 15 μm.

As the binder resin applicable to the toner of the present invention, all known binder resins can be used. For example, styrene such as polystyrene, poly p-chlorostyrene, polyvinyltoluene and a homopolymer of a substituted product thereof, styrene-p-chlorostyrene Styrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-
Butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl acrylate copolymer,
Styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer,
Styrene-vinyl ethyl ether copolymer, styrene
Styrenes such as vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer Copolymer, polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, polyamide, epoxy resin, polyvinyl butyral, polyacrylic resin, rosin, modified rosin, terpene resin, phenol Resins, aliphatic or alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins, paraffin waxes and the like can be used alone or in combination.

Further, a load control agent may be added to the toner of the present invention as needed. For example, in the case of a negative toner, a dye having an anthraquinone-based magenta color or a metal chelate of alkyl salicylic acid is used, and in the case of a positive toner, a magenta basic dye or a lake thereof is used. Pigments and the like can be used.

When a carrier is used for the developer, a conventionally known carrier can be used. For example, surface oxidized or unoxidized iron,
Metals such as nickel, copper, zinc, cobalt, manganese, chromium, and rare earths, and alloys or oxides thereof, and ferrites composed of the above metals can be used, and there is no particular limitation on the production method.

Further, a system in which the surface of the carrier is coated with a resin or the like,
Particularly preferred as the developer of the present invention. As the method, any of a method of dissolving or suspending a coating material such as a resin in a solvent, applying the coating material, and attaching the coating material to a carrier, a method of simply mixing with a powder, and a conventionally known method can be applied.

Further, for a developer in which the toner of the present invention is used, a fluidity modifier such as colloidal silica is added to the toner in an amount of 0.1%.
About 01% to 5% by weight (preferably 0.1% to 2% by weight) is added.

Next, a general method for producing the magenta toner of the present invention will be described.

First, a resin and a colorant (charge control agent in some cases) are uniformly dispersed by a Henschel mixer or the like, and then melt-kneaded by a kneader, an extruder, a roll mill, or the like. Next, the kneaded material is roughly pulverized by a cutter mill, a hammer mill or the like, and further finely pulverized by a jet mill, an I-type mill or the like. DS of pulverized material,
The particles are classified by a zigzag classifier, and silica or the like is dispersed in the classified material by a Henschel mixer or the like.

As the colorant used in the magenta toner of the present invention, a polymerized toner manufactured by a suspension polymerization method may be used.

[Examples] Hereinafter, the present invention will be described in detail with reference to Examples. All parts in the examples are parts by weight.

Example 1 The above compounds are mixed by a Henschel mixer, melt-kneaded by a roll mill, cooled, and finely pulverized by a jet mill.
The obtained fine powder was classified to obtain a classified product having a volume average particle size of 12 μm. 0.5 parts of colloidal silica was externally added to the classified product using a Henschel mixer to obtain a magenta toner. To 60 parts of this magenta toner, 940 parts of a carrier (resin-coated ferrite carrier made of a mixture of a styrene acrylic copolymer and a vinylidene fluoride polymer, average particle size 70 μm) were mixed to prepare a developer.

Using this developer, a copy test was performed using a full-color copying machine (product name: CLC-1, manufactured by Canon Inc.) equipped with a color electrophotographic apparatus having an OPC photosensitive drum shown in FIG. The color tone of the obtained image was vivid magenta. When a forced irradiation test was performed using a fade meter (trade name: Super Fade Meter, manufactured by Suga Test Instruments Co., Ltd.), no fading was observed after 40 hours of irradiation, and it was found that there was no problem with light resistance. When 20,000 sheets were continuously copied, no contamination of the silicone rubber roller was observed, no high-temperature offset occurred, and no image deterioration due to spent carrier was observed.

Example 2 With the above formulation, the volume average particle size was 8 μm in the same manner as in Example 1.
When the magenta toner was prepared and evaluated, it was an image having good spectral reflection characteristics (color characteristics), dispersibility, and light fastness. In addition, the toner had stable triboelectric charging characteristics, and no contamination on the surface of the fixing roller or spent on the carrier surface was observed.

Example 3 With the above formulation, the volume average particle diameter was 10 μm in the same manner as in Example 1.
A magenta toner was prepared and evaluated. As a result, an image having good spectral reflection characteristics and excellent dispersibility and light fastness was obtained.
In addition, good triboelectric charging characteristics were exhibited even under high temperature and high humidity, and no contamination of the fixing roller and no spent surface of the carrier were observed. In addition, good transparency was exhibited by copying on an OHP sheet.

Comparative Example 1 When a toner was prepared and evaluated in the same manner as in Example 1 with the above formulation, an image having good spectral reflection characteristics and light fastness was obtained. However, the triboelectric charge amount was higher than that in Example 1 under high temperature and high humidity. The toner was attached to the non-image area, that is, fogging was observed in repeated copying.

Comparative Example 2 A toner was prepared and evaluated in the same manner as in Example 1 with the above formulation. The hue was shifted to the red side due to the color of the copy, and the magenta color was considerably poor in saturation.

[Effects of the Invention] As described above, the magenta toner of the present invention provides clear color images from low-temperature and low-humidity to high-temperature and high-humidity environments without contaminating a copying machine.

[Brief description of the drawings]

FIG. 1 is a schematic view of a full-color copying machine equipped with a color electrophotographic apparatus.

Claims (2)

(57) [Claims] (1) at least a key for 100 parts by weight of a binder resin;
A nacridone-based colorant and represented by the following general formula (I)
A colorant comprising a xanthene-based colorant is added in a total amount of 2 to 20.
Magenta toner contained by weight.
The addition ratio of the tin colorant and the xanthene colorant (g
Nacridone colorant / xanthene colorant) is 4.5 / 0.
5 to 6.0 / 1.0, and the fluidity modifier is
Characterized in that 0.01 to 5% by weight is added.
Zenta toner. General formula (I)[R in the general formula (I)₁~ R₆Is -H or C_nH_{2n + 1})
An alkyl group represented by the formula (n = 1 to 5) or C:_nH
_2n-1An alkenyl group represented by (n = 2 to 5)
R₇Is -H or C_nH_{2n + 1}) (N = 1-5)
Is an alkyl group represented by A Is SO_Three ^-, HCO_Three ^-, H_TwoPO_Four
^-Is an anion of ] 2. The magenta toner according to claim 1, wherein the fluidity modifier is colloidal silica.