JPH0572817A - Electrophotographic liquid developer - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic liquid developer of red, yellow, blue or black color which is safe and causes no environmental pollution by using an oil or fat as a carrier liquid, a specified coloring agent, and further a specified polarity controlling agent. CONSTITUTION:The carrier liquid contains at least a coloring agent and a specified polarity controlling agent. An oil or fat which is glyceride of fatty acid is used as the carrier. As for the coloring agent, at least one food additive coloring material selected from the following groups A (red), B (yellow), C (blue), and D (black). A:beta-carotin, norbixim potassium, etc. B: 1-phenylazo-2- naphthol-4', etc. C: copper chlorophyll, etc. D: CI FOOD Black 1, etc. As for the polarity controlling agent, harmless fatty acid ester is used. Therefore, the coloring material shows good dispersibility in the carrier liquid and excellent affinity with the polarity controlling agent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safe liquid phenomenon liquid for electrophotography without environmental pollution.

[0002]

2. Description of the Related Art In wet electrophotography using a liquid developer, high resolution and image quality have been obtained and reliability is high. However, in the general market, since hydrocarbons obtained from petroleum are used as carrier liquids, environmental pollution due to odors and steam is a problem, and the vapors of carrier liquids can pollute the air in the office. It's a problem.

The following carrier liquids have been used for liquid developers that have been conventionally used. That is, ligroin, n-hexane, n-pentane, n-heptane, n-
Octane, i-octane, i-dodecane, i-nonane (these commercial products include Isopar manufactured by Exxon Co., Shell Petroleum Co., Shelsol, etc.). In addition to this, in recent years, silicone oil, fluorine oil, mineral oil and the like have begun to be proposed. Mineral oil is a substance proposed for environmental protection, without volatilizing highly volatile hydrocarbons,
The purpose is to be able to utilize liquid developers.

However, carbon black and synthetic colorants and dyes are still used as the colorant still used as toner particles, and methyl (meth) acrylate, paraphone and the like are used as the binder resin. ing.
In addition, organometallic complexes and organometallic soaps are often used as the polarity control agent. Each manufacturer also conducts oral toxicity tests and skin irritation tests on the raw materials used for these developers to confirm safety before production.
It is not completely safe.

[0005]

SUMMARY OF THE INVENTION According to the present invention, a latent image on a photoreceptor is developed with a developer for electrophotography, and the developed image is transferred onto a copy paper (final printed matter) to obtain an image with high resolution. In order to achieve this, it is necessary for the colorant to be sufficiently dispersed in the carrier liquid and to maintain sufficient chargeability due to the interaction with the polarity control agent of the third substance. It is an object of the present invention to select a material for an electrophotographic developer that satisfies the above requirements and is safe for use without causing environmental pollution.

[0006]

DISCLOSURE OF THE INVENTION As a result of intensive investigations by the present inventors, in a liquid developer for electrophotography containing at least a coloring agent and a polarity control agent in a carrier liquid, fatty acid Using oils and fats that are glycerides, as colorants, the following red group A, yellow group B, and blue C are shown.
Group, or by using at least one food additive colorant of each group of black group D, shows good dispersibility in the carrier liquid, red, yellow, which has an excellent affinity with polar agents, It has been found that a blue or black electrophotographic liquid developer can be obtained. If necessary, the red group A,
The yellow color groups B, the blue color groups C, or the black color groups D may be combined with each other.

(Coloring agent of group A) β-carotene, norbixin potassium, norbixin sodium, 2-hydroxyazonaphthalene, trisodium 3,4 ', 6-trisulfonate, 2', 4 ', 5 ', 7'-Tetraiodofluorescein sodium, 2-hydroxyazonaphthalene-4',
Trisodium 6,8-trisulfonate, 2 ', 4', 5 ', 7'
-Tetrabromo-3,4,5,6-tetrachlorofluorescein disodium, 3,4,5,6-tetrachloro-
2 ', 4', 5 ', 7'-Tetraiodofluorescein trisodium, 3,6-bis (diethylamino) -xanthylium-9- (2,4-benzenedisulfonate) sodium.

(Group B Colorant) 1-Phenylazo-2-
Naphthol-4 ', 6-disulfonic acid disodium salt, 3
-[N-Ethyl-N- [4- [4-ethyl-N- (3sulfonatebenzyl) aminophenyl]-(4-hydroxy-2-sulfonatephenyl) methylene] -2,5
-Cyclohexydienylidene] ammoniomethyl] sodium benzenesulfonate, 3-carbonate-5-hydroxy-1- (4-sulfonatephenyl) -IH-
Pyrazole-4-azo- (4'-benzenesulfonic acid)
Trisodium, 2-hydroxy-6-sulfonaphthalene-1-azo- (4′-benzenesulfonic acid) disodium.

(Group C Coloring Agent) Copper chlorophyll, sodium copper chlorophyllin 3,3'-dioxo-2,2'-
Bindolinylidene-5,5'-disodium disodium salt.

(Colorants of Group D) CI FOOD Black 1 and CI Food Black 2.

In addition to fats and oils that are liquid at room temperature (10 to 30 ° C.) as carrier liquids, when fats and oils that are solid at room temperature are used, they solidify during cooling and are easy to handle. It has been found that a secondary effect can be obtained in which a fixing heater or the like used for toner is unnecessary.

It has also been found that a harmless fatty acid ester can be used as the polarity control agent.

The fats and oils of the carrier liquid used in the present invention are as follows. Dry vegetable oil; linseed oil, camara oil, walnut oil, poppy oil,
Soybean oil, ash seed oil, eggplant seed oil, etc. Semi-dry plants; barley oil, oak seed oil, pumpkin seed oil, unse kernel oil, etc. Animal oil; beef tallow, pork oil, horse oil, sardine oil, charr oil, flounder oil, salmon oil Oil, herring oil, industrial herring oil, etc. Liver oil; Shark liver oil Whale oil, dolphin oil, hydrogenated oil, etc. Wood-drying vegetable oils; Akebei seed oil, olive oil, coffee bean oil, camellia oil, etc.

Among the fats and oils, those that are solid at room temperature (10 to 30 ° C) include beef tallow (melting point 44 to 45 ° C), carnauba wax (melting point 72 to 86 ° C), and beeswax (melting point 60 to 60 ° C).
66 ° C.) and so on. When a colorant and a polarity control agent are dispersed in these and heated at the time of development to form a liquid phenomenon liquid, there is also an effect that a fixing heater such as a conventional toner is unnecessary.

Examples of the fatty acid ester usable as the polarity control agent include fatty acid esters of lecithin, glycerin and sucrose.

[0016]

EXAMPLES Examples will be described below, but the present invention is not limited to the materials, constitutions, conditions, and means for carrying out the examples. <Example 1> 200 g of soybean oil, trihydroxysodium 2-hydroxyazonaphthalene-4 ', 6,8-trisulfonate 50
Add 5 g of lecithin to 3 g, and use a ball mill to mix at 25 ° C for 3
Dispersed for 0 hours. This dispersion was dispersed in 1000 g of soybean oil to obtain a liquid developer. When this liquid developer was placed in DT-1300 manufactured by Ricoh Co., and copying was performed, a good red image was obtained.

<Example 2> 500 g of industrial herring oil and 2
-Hydroxy-6-sulfonaphthalene-1-azo-
100 g of (4'-benzenesulfonic acid) disodium
20 g of propylene glycol acid ester was added to and dispersed in a ball mill for 60 hours. 1000 herring oil
g was added to obtain a safe liquid developer. This liquid developer is DT. When it was placed in a 5700 and copied, a good yellow image was obtained.

<Example 3> 200 g of linseed oil and 3,3'-
50 g of disodium dioxo-2,2'-bindolinylidene-5,5'-disulfonate and 10 g of propylene glycol ester were added and dispersed in a ball mill for 40 hours. After that, 1000 g of linseed oil was added to obtain a safe edible phenomenon liquid. This liquid developer is DT-1 manufactured by Ricoh Company.
When it was placed in 200 and copied, a good blue image was obtained.

Example 4 200 g of beef tallow (melting point 35 ° C.)
And C of the following structure. J. 50 g of Food black 1 together with 10 g of sosorbitan fatty acid ester in a ball mill 4
Disperse at 0 ° C. for 60 hours. Then add 40 g of beef tallow
The mixture was mixed and dispersed at a temperature of ° C to obtain an edible developer.
When a heater was added to the developing tank of DT-1200 manufactured by Ricoh Co., Ltd., and the image forming agent was put into a place where the liquid temperature was raised to 45 ° C., and copying was performed, a good black image was obtained.

[0020]

According to the present invention, by using fats and oils as a carrier liquid, a colorant used as a food additive as a colorant, and a harmless fatty acid ester as a polarity control agent, no environmental pollution occurs. Safe red, yellow, blue, or black electrophotographic liquid developers can be obtained.

Claims (6)

[Claims] 1. A liquid developer for electrophotography comprising a carrier liquid containing at least a colorant and an extreme control agent, wherein the carrier liquid is oil and fat, and the colorant is a red A used as a food additive. A liquid developer for electrophotography, comprising at least one of a group of colorants. (Group A colorant) β-carotene, norbixin potassium, norbixin sodium, 2-hydroxyazonaphthalene, 3,4 ′, 6-trisulfonic acid trisodium salt,
2 ', 4', 5 ', 7'-Tetraiodofluorescein-2
-Sodium, 2-hydroxyazonaphthalene-4 ',
Trisodium 6,8-trisulfonate, 2 ', 4', 5 ', 7'
-Tetrabromo-3,4,5,6-tetrachlorofluorescein disodium, 3,4,5,6-tetrachloro-
2 ', 4', 5 ', 7'-Tetraiodofluorescein disodium, 3,6-bis (diethylamino) -xanthylium-9- (2,4-benzenedisulfonate) sodium. 2. A liquid developer for electrophotography comprising a carrier liquid containing at least a colorant and a polarity control agent, wherein the carrier liquid is a fat and oil, and the colorant is used as a food additive. A liquid developer for electrophotography, comprising at least one of the colorants described in 1. (Group B Colorant) 1-Phenylazo-2-naphthol-
Disodium 4 ', 6-disulfonate, 3- [N-ethyl-N- [4- [4-ethyl-N- (3sulfonatebenzyl) aminophenyl]-(4-hydroxy-2-sulfonatephenyl) Methylene] -2,5-cyclohexydienylidene] ammoniomethyl] sodium benzenesulfonate, 3-carbonate-5-hydroxy-1
-(4-Sulfonatophenyl) -1H-pyrazole-
4-azo- (4'-benzenesulfonic acid) trisodium, 2-hydroxy-6-sulfonaphthalene-1-azo- (4'-benzenesulfonic acid) disodium. 3. A liquid developer for electrophotography, comprising a carrier liquid containing at least a colorant and a polarity control agent, wherein the carrier liquid is an oil and fat, and the colorant is used as a food additive. A liquid developer for electrophotography, which comprises at least one colorant. (Colorant of Group C) Copper chlorophyll, copper chlorophyllin sodium, 3,3'-dioxo-2,2'-binindolinidene-5,5'-disulfonic acid disodium salt. 4. A liquid developer for electrophotography comprising a carrier liquid containing at least a colorant and a polarity control agent, wherein the carrier liquid is a fat and oil, and the colorant is a black group D dye used as a food additive. A liquid developer for electrophotography, which comprises at least one colorant. (Group D colorant) CI FOOD Black1, CI Food Black2 5. The liquid developer for electrophotography according to claim 1, 2, 3, or 4, wherein the oil and fat is a solid at room temperature. 6. The liquid developer for electrophotography according to claim 1, wherein the polar control agent is a fatty acid ester.