JPH0562328B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a color toner, and particularly to a color toner using a negatively charged polyester resin as a binder resin.

BACKGROUND OF THE INVENTION Polyester resins generally have sufficient triboelectric charge of negative polarity. On the other hand, there are many types of polyhydric carboxylic acids and polyhydric alcohols that can be used as esterifying agents. Therefore, the electromagnetic properties, thermal properties, etc. of the polyester resin obtained using these esterifying agents can be freely adjusted, making it easy to match the copying machine and the toner. If a polyester resin is used as a binder resin for a toner, it is therefore possible to fully meet market demands such as improved image characteristics, reduced maintenance, energy saving, and increased speed. However, since this polyester resin has a large negative charging property, when it is used as a binder resin for a toner, the negative charging property of the polyester resin on the surface of the toner particles causes the distribution of negative charges to become too uniform, resulting in an electrostatic latent image. Negative polarity toners in the toner image developed above repel each other.
This causes toner scattering and blurring of the image at the periphery of the image.

OBJECT OF THE INVENTION An object of the present invention is to provide a color toner using a polyester resin as a resin binder. Another object of the present invention is to disperse positive charges caused by a positive charge control agent in the uniform distribution of negative charges on the surface of the toner formed by the polyester resin, thereby preventing repulsion between the toners and producing color with excellent resolution. The goal is to provide toner.

SUMMARY OF THE INVENTION In the present invention, the reason why the resolution of the color toner using polyester resin as a binder is low is because the polyester resin has a large amount of negative charge and the negative charge on the toner surface is too uniform, which causes the toners to be separated from each other. By interspersing the positive charges caused by the positive charge control agent in the distribution of negative charges on the surface of the toner particles, the toner particles repel each other without damaging the amount of triboelectric charge of the toner as a whole. This was completed based on the inventor's knowledge that repulsion is suppressed and resolution is improved. Therefore, the color toner of the present invention is
In a color toner whose main components are a negatively charged polyester resin and a colorant, 0.05 to 0.7 parts by weight of a positive charge control agent per 100 parts by weight of the polyester resin is uniformly distributed so that a part of it is exposed on the surface. distribution, thereby achieving the above objective.

The polyester resin used as a binder in the present invention is obtained, for example, by condensation polymerization of a diol component represented by the following general formula and a polyhydric carboxylic acid, its acid anhydride, or a derivative as an acid component. The polyester resin thus obtained is preferably used in terms of non-offset properties and fixing properties. : Here, R is an ethylene group or a propylene group, and m and n are positive integers.

As the diol component represented by the above general formula (1), polyoxypropylene-2,2-bis(4-
hydroxyphenyl)propane; polyoxyethylene-2,2-bis(4-hydroxyphenyl)
Propane; polyoxypropylene-polyoxyethylene-2,2-bis(4-hydroxyphenyl)propane and the like can be mentioned. Carboxylic acid components include maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, malonic acid, and linoleic acid. acid, 1,2,4 benzenetricarboxylic acid, 1,
2,5 benzenetricarboxylic acid, 1,2,4 cyclohexanetricarboxylic acid, 2,5,7 naphthalenetricarboxylic acid, 1,2,4 naphthalenetricarboxylic acid, 1,2,5 hexanetricarboxylic acid,
1,2,4butanetricarboxylic acid, 1,3-dicarboxy-2-methylcarboxypropene, 1,
Mention may be made of 3-dicarboxy-2-methyl-2-methylcarboxypropane tetra(methylenecarboxy)methane, 1,2,7,8 octane tetracarboxylic acid, embol trimer and acid anhydrides thereof.

In the condensation polymerization of the diol component and the polyhydric carboxylic acid component, the number of carboxyl groups in the carboxylic acid component is preferably 1.2 to 0.8, particularly 1.1 to 0.9, relative to the number of hydroxyl groups in the diol component. . In this case, as a catalyst, for example, tin oxide, zinc oxide, titanium oxide, dibutyltin oxide, dibutyltin diurarate, etc. can be used. In addition to the etherified bisphenol represented by the general formula (1), other diol components such as ethylene glycol and bisphenol A can be used in combination within a range of 10 mol%.

Coloring agents used in the present invention include, for example, the following organic pigments: Yellow pigment: Hanser Yellow G; Hanser Yellow 10G;
Hanser Yellow GR; Hanser Yellow 5G;
Hanser Yellow 3G; Benzidine Yellow G; Benzidine Yellow GR; Quinoline Yellow Lake;
Permanent Yellow NCG, Orange Pigment: Permanent Orange GTR; Pyrazolone Orange; Vulcan Orange; Indan Thren Prilliant Orange RK; Benzidine Orange G;
Indanslen Priliant Orange GK; Vulcan Orange, Red Pigment: Prilliant Fast Scarlet; Permanent Red 4R; Lysol Red; Pyrazolone Red; Watching Red Calcium Salt; Lake Red D; Prilliant Carmine 6B; Eosin Lake; Rhodamine Lake B; Alizarin Lake; Prilliant Carmine 3B; Toluidine Red; Permanent Red F4RH; Violet Pigment: Fast Violet B; Methyl Violet Lake; Crystal Violet Lake; Rhodamine B; Blue Pigment: Victoria Blue Lake; Phthalocyanine blue; metal-free phthalocyanine blue; partially chlorinated phthalocyanine blue; first sky blue; indanthrene blue BC; and green pigments: Pigment green B; malachite green lake; phanal yellow green G; diamond green lake; green gold ; Phthalocyanine green.

The above-mentioned organic pigment can be used in the polyester resin.
It is used in amounts of 1 to 15 parts by weight per 100 parts by weight.
If the amount is less than the above range, the color tone as a color toner will not be maintained. If the amount exceeds the above range, the pigment itself may be released from the resin binder and contaminate the carrier.

The positive charge control agent used in the present invention scatters positive charges in the distribution of negative charges on the surface of toner particles without significantly reducing the amount of negative charges possessed by the polyester resin as a binder. The amount used is 0.05 to 0.7 parts by weight per 100 parts by weight of polyester resin, preferably
It is 0.1 to 0.5 parts by weight. If too little positive charge control agent is used, uniform distribution of negative charges on the surface of the toner particles cannot be prevented. If the amount is too large, the amount of charge on the toner decreases, making it impossible to obtain a desired developed image.

Positive charge control agents are those that can be positively charged by friction with the carrier, and include, for example, the following: Oleosol Blue G (CISolvent Blue 11), Oriental Oil Blue K (CISolvent).
Blue 12), Orient Oil Blue BO (CISolvent Blue
25), Sudan Blue (CISolvent Blue 35), Sumipurato Blue OA (CISolvent Blue
36), Zapon First Blue FLE (CISolvent
Blue 55), CISolvent Blue
73), CISolvent Green
3) Orient Oil Black HBB (CISolvent
Black 3), Nigrosine Base (CISolvent Black 7), Victoria Blue (CISolvent Blue 2), Orient Oil Yellow GG (CISolvent
Yellow 2), Zapon First Yellow CGG (CISolvent
Yellow 15), Eizenspiron Yellow GRH (CISolvent
Yellow 61), Iketon Yellow GRextra (CISolvent
Orange 1), Izenspiron Orange GRH (CISolvent
Orange 37), Eisen Spiron Ferry Red BH (CI
Solvent Red 81), Izenspiron Pink BH (CISolvent Red
82), Eizen Spiron Red BEH (CISolvent
Red 83), Orient Oil Violet #730 (CI
Solvent Violet 13), Eisenspiron Violet RH (CI
Solvent Violat 2 1) Among the above charge control agents, the one most useful for the present invention is nigrosine-based because of its positive charging performance. Nigrosine base itself has a blackish-purple color, but in the present invention, the amount used is so small that it hardly affects the color tone of the toner.

The average particle size of the charge control agent is preferably 3 μm or less. If the particle size becomes too large, it becomes difficult to uniformly disperse the particles into individual toner particles, and as a result, it becomes impossible to uniformly scatter positive charges on the toner surface, and the object of the present invention cannot be achieved.

In the color toner of the present invention, silicone oil, silicone oil,
Offset inhibitors such as low molecular weight olefins and various waxes may be used in an amount of 2 to 15% by weight of the total. For applications where the developer is fixed with a pressure roll, paraffin wax, various animal/vegetable waxes,
Pressure fixing agent such as fatty acid amide accounts for 5~
It can be used in a proportion of 30% by weight.

The color toner of the present invention has positive charges interspersed in the distribution of negative charges on the surface of the toner particles. In positively charge dotting, the charge control agent needs to be partially exposed on the toner surface. The charge control agent is usually a fine powder and is uniformly dispersed in the toner. Therefore, as a method for exposing the fine powder of the charge control agent on the toner surface, the charge control agent can be exposed with a certain probability by using the pulverization method of the toner manufacturing method. Therefore, the color toner of the present invention is produced by kneading various components such as a polyester resin, a colorant, and a positive charge control agent by three-roll, twin-screw extrusion, etc., cooling the resulting kneaded composition at room temperature, Then, this is coarsely ground and then finely ground until the average particle size is 5 to 25 μm.
It can be obtained by classifying so that The particle size of the color toner particles is usually preferably in the range of 5 to 25 μm.

Further, in order to further improve the fluidity of this color toner, a fluidizing agent such as vapor phase silica may be added by means such as dry blending or sprinkling, if necessary.

Example The present invention will be described below with reference to Examples.

Example 1 Bisphenol type polyester resin (ATR-
2010, Kao Soap Co., Ltd.) 100 parts by weight, red azo lake pigment (Fast-Red 2BE-1218, CI Pigment)
6 parts by weight of Red 48 (manufactured by Sanyo Shiki Co., Ltd.) and Nigrosine Base (Nigrosine Base EX, manufactured by Orient Chemical Co., Ltd.) were heated and kneaded at 150°C in a twin-screw extruder PCM-30. After cooling, the kneaded material is coarsely pulverized with a hammer mill and then finely pulverized with an ultrasonic jet mill. The obtained fine powder was classified using a zigzag classifier to obtain a red toner having a particle size distribution of 5 to 25 μm. In order to understand the distribution of the charge control agent in the obtained red toner, the particle cross section was observed using an electron microscope using a microtome, and it was confirmed that the nigrosine base was uniformly exposed on the surface. To this, R-972 (vapor phase silica, manufactured by Nippon Aerosil)
and Al ₂ O ₃ -C (vapor-phase alumina, manufactured by Nippon Aerosil Co., Ltd.) were added in amounts of 0.1 wt % and treated on the toner surface using a Henschel mixer. A developer was obtained by mixing 100 parts by weight of iron powder carrier (STV-25T, manufactured by Nippon Tetsuko Co., Ltd.) with 10 parts by weight of this toner. When this developer was copied using a commercially available PPC (DC-131, manufactured by Sanda Kogyo Co., Ltd.), a clear red copy with an image density of 1.24, a background fog density of 0.001 or less, and no image blurring and excellent resolution was obtained. The amount of blow-off triboelectric charge of this developer was measured - 24.3μc/g
It was hot.

Comparative Example 1 A toner was obtained in exactly the same manner as in Example 1 except that Nigrosine Base EX was removed. Copying was carried out using a commercially available PPC-DC-131 in the same manner as in Example 1, and a red copy was obtained in which the image was significantly blurred and fine lines were blurred, making it unsuitable for practical use. The amount of blow-off triboelectric charge of this developer was measured and found to be -31.4 .mu.c/g.

Example 2 Bisphenol type polyester resin (ATR-
2010) 100 parts by weight, 6 parts by weight of blue phthalocyanine pigment (Cyanine Blue FG, manufactured by Sanyo Shiki Co., Ltd.) and 0.3 parts by weight of Nigrosine Base EX (average particle size 2.0 μm) were made into a toner in exactly the same manner as in Example 1.
When copying was performed using a commercially available PPC DC-131 in the same manner as in Example 1, in which a blue toner with a particle size distribution of ~20 μm was obtained, the image density was 1.29, the background fog density was less than 0.001, and the image had excellent resolution with no image blurring. I got a clear blue copy. The amount of blow-off triboelectric charge of this developer was measured -20.5μC/g
It was hot.

Comparative Example 2 A toner was obtained in exactly the same manner as in Example 1, except that Nigrosine Base EX was removed from the composition of Example 2. Similarly, when copying was performed using a commercially available PPC DC-131, a blue copy was obtained which was unsuitable for practical use as the image was blurred and the fine lines were too faint. The amount of blow-off triboelectric charge of this developer was measured.
It was 26.1μc/g.

Effects of the Invention In the color toner of the present invention, as described above, the positive charge control agent is uniformly distributed so that a part of it is exposed on the surface, so that the toner can be easily charged without damaging the amount of triboelectric charge of the toner as a whole. This suppresses the repulsion between the two toner particles, and suppresses toner scattering and image blurring at the periphery of the image. As a result, it becomes possible to obtain an image with excellent resolution.

Claims (1)

[Scope of Claims] 1. A color toner containing a negatively charged polyester resin and a colorant as main components, in which part of the toner contains 0.05 to 0.7 parts by weight of a positive charge control agent per 100 parts by weight of the polyester resin. Color toner that is uniformly distributed and exposed on the surface. 2. The color toner according to claim 1, wherein the positive charge control agent is based on nigrosine. 3. The color toner according to claim 1, wherein the positive charge control agent has an average particle size of 3 μm or less.