JPH0619590B2 - Color toner for electrophotography - Google Patents

Description

TECHNICAL FIELD The present invention relates to a color toner used in a color electrophotographic method, and more particularly to a magenta toner suitable for a full-color copying machine using a heat fixing device having a silicon rubber roller.

[Prior Art] Conventionally, as colorants for magenta toners for color electrophotography, there are azo lake pigments, anthraquinone dyes, quinacridone pigments, rhodamine dyes and their lake pigments.

Among them, rhodamine dyes are suitable as magenta colorants because they have good color characteristics (obtain vivid colors) and high coloring power. For example
59-57256 describes rhodamine B based dyes.

However, this dye easily penetrates into the silicone rubber roller, causes the roller surface to be dyed in magenta color, and tends to cause early offset. Further, the light resistance is poor, and when the copy is exposed to sunlight, it is discolored in a short time.

Further, astrafloxin (CI Basic Red 12) which is a methine dye described in JP-A-58-118653 is also introduced as a magenta dye.

However, this dye has a yellowish pink color and cannot be used alone as a magenta coloring agent. In addition, the light resistance is insufficient and there is a practical problem.

[Problems to be Solved by the Invention] An object of the present invention is to provide a magenta coloring agent that solves the above-mentioned conventional problems. That is, it is an object of the present invention to provide a magenta coloring agent that can obtain a vivid color, has a large coloring power, does not dye a silicone rubber fixing roller, and has excellent light resistance.

[Means and Actions for Solving Problems] According to the present invention, both a compound classified into CI Basic Red 12 and a compound classified into CI Disperse Violet 31 are contained for color electrophotography. Magenta toner is provided.

The structural formulas of the compounds classified in CI Basic Red 12 are as follows.

The structural formulas of the compounds classified as CI Disperse Violet 31 are as follows.

In the present invention, the reason for using two kinds of colorants in combination is as follows. CI Disperse Violet 31 has good tinting strength and light resistance, has low roller dyeability, and can be used alone as a magenta dye, but it has a strong blue tint and is somewhat problematic in practice. On the other hand, CI Basic Red 12 has high roller dyeing ability, insufficient light resistance, and is also unsuitable in tint, and cannot be used alone, but CI Disperse Violet
The effect of alleviating the blue tint of 31 and enhancing the sharpness is great.

The amount of the colorant added in the present invention is preferably 0.1 to 10.0 parts by weight, and particularly preferably 0.2 to 3.0 parts by weight, based on 100 parts by weight of the binder resin, as a total amount of both colorants. In addition, the addition ratio of both coloring agents is CI Basic Red in order to obtain the above effect.
The range of 12 / CI Disperse Violet 31 = 1/9 to 5/10 is preferable. CI Basic Red 12 addition amount is CI Disper
If it exceeds 1/2 of se Violet 31, the light resistance tends to deteriorate.

As the binder resin used in the present invention, polystyrene,
Monopolymers of styrene such as poly-p-chlorostyrene and polyvinyltoluene, and their substitution products; styrene-p-chlorostyrene copolymers, styrene-propylene copolymers, styrene-vinyltoluene copolymers, styrene-vinylnaphthalene copolymers Polymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-
Butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethacrylic acid Methyl copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer Styrene-based copolymers such as polymers, styrene-acrylonitrile-indene copolymers, styrene-maleic acid copolymers, styrene-maleic acid ester copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyacetic acid Vinyl, poly Tylene, polypropylene, polyester, polyurethane, polyamide, epoxy resin, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorination Paraffin, paraffin wax and the like can be used, and they can be used alone or as a mixture.

Further, a charge control agent may be added to the toner of the present invention, if necessary. For example, an anthraquinone-based magenta dye or a metal chelate of alkylsalicylic acid can be used for a negative toner, and a magenta basic dye or a lake pigment thereof can be used for a positive toner. .

When a carrier is used as the developer, a conventionally known one can be used. Examples thereof include magnetic substances such as iron, cobalt and nickel, alloys and mixtures of these, and those whose surfaces are coated.

Further, for the developer in which the toner of the present invention is used, a fluidity modifier such as colloidal silica is added to the toner.
You may add about 0.01-5 weight% (preferably 0.1-2 weight%).

The general method for producing the magenta toner of the present invention is as follows.

The resin and the colorant (and optionally the charge control agent) are uniformly dispersed by a Henschel mixer or the like.

The dispersion is melt-kneaded with a kneader, an extruder, a roll mill or the like.

After roughly kneading the kneaded product with a cutter mill, a hammer mill, etc., it is finely crushed with a jet mill, an I-type mill and the like.

Classify the finely pulverized material with a DS or zigzag classifier.

Depending on the case, silica or the like is dispersed in the classified product with a Henschel mixer or the like.

As another method, the suspension polymerization method can be used.

[Example] Example 1 The above materials were melt-kneaded by a roll mill, cooled, finely pulverized by a jet mill and classified to obtain a classified product having an average particle diameter of 9 μm. To this classified product, 0.5% by weight of hydrophobic silica (Aerosil R-972, manufactured by Nippon Aerosil Co., Ltd.) was externally added with a Henschel mixer to obtain a magenta toner. This toner is mixed with carrier iron powder (TEFV 200/300, Nippon Iron Powder Co., Ltd.),
Used as a developer.

Using this developer, a full-color copying machine (NP-COLOR-T,
20,000 copies were continuously made with Canon). When the fixing roller made of silicone rubber was observed, dyeing with the dye did not occur. The tint of the obtained copy is a vivid magenta color and has a sufficient tint as a magenta toner. To see the light resistance of the copy, use a fade meter (Super Fade Meter, Suga Test Instruments Co., Ltd.)
A 20-hour forced irradiation test was performed (irradiation conditions are based on JIS regulations). No fading of magenta color was observed even after irradiation for 20 hours. It was found that the light resistance was practically no problem.

Example 2 A developer was prepared using the above materials and evaluated in the same manner as in Example 1. However, the tint, roller dyeability, and light resistance were all sufficiently satisfactory.

Example 3 A developer was prepared using the above materials and evaluated in the same manner as in Example 1. However, the tint, roller dyeability, and light resistance were all sufficiently satisfactory.

Comparative Example 1 A developer was prepared in the same manner as in Example 1 with the above formulation, and then evaluated. After continuous copying started, the fixing roller began to dye magenta around 5,000 sheets, and hot offset occurred at 7,000 sheets. Observation of the fixing roller revealed that remarkable dyeing had occurred.

Further, the light resistance was evaluated with a fade meter, and the fading was remarkable after 20 hours of irradiation. When the image density of the copy was measured, the density of 1.38 without irradiation was 0.70 after irradiation for 20 hours.
Was falling to.

[Effect of the Invention] As described above, by using the compound classified into CI Basic Red 12 and the compound classified into CI Disperse Violet 31 together, a clear magenta color can be obtained.

There is no dyeing on the silicone rubber roller.

Light resistance is improved.

There are advantages such as.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenji Okado, Kenji Oka-ku, Tokyo 3-30-2 Shimomaruko, Canon Inc. (72) Inventor Hiroyuki Suematsu 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (56) References JP 59-219756 (JP, A) JP 61-118759 (JP, A)

Claims (1)

[Claims] 1. Sea. Eye. Basic Red 12 (CI Ba
Compounds classified as sic Red 12) and C.I. Eye. CI Disperse Violet 31
A magenta toner for color electrophotography, which further comprises: