JPH0260183B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel dry negatively charged toner for developing electrostatic latent images in electrophotography, electrostatic recording, electrostatic printing, and the like. Originally, an electrostatic latent image can be developed and visualized by adhering toner due to its electrostatic attraction, but in this case, in addition to liquid developer, powder Developers are widely used. This powder developer is made from a mixture of a toner with an average particle size of 15 μm, which is made by dispersing colorants, charge control agents, fluidizing agents, etc. in natural or synthetic resin, and a carrier of iron powder or ferrite powder with a diameter of 100 to 200 μm. become 2
Developers can be roughly divided into component-based developers and one-component developers, which are composed of a natural or synthetic resin, a colorant, a charge control agent, a fluidizing agent, and a magnetic material. A two-component developer achieves development by attaching charged toner to an electrostatic latent image through friction with a carrier. Conventionally, a one-component developer uses this instead of a carrier. Toner is known that is charged by friction with a brush-like or plate-like friction member that has the same function as that of a brush-like or plate-like friction member. It has become known that toner is charged by mutual friction with powder. Then,
These developing toners are kept positively or negatively charged depending on the polarity of the electrostatic latent image to be developed. In order to keep the toner charged, it has been proposed to utilize the triboelectricity of the resin, which is the main component of the toner, but this method has a small charge on the toner and a large solid surface resistance value, so The resulting image is prone to fogging and becomes unclear. Therefore, in order to impart the desired triboelectricity to the toner,
Dyes, pigments, and even charge control agents that impart a charge are added to the toner, and the ones currently in practical use in this technical field include those that impart a positive charge to the toner. There are nigrosine-based oil-soluble dyes as shown in Publication No. 41-2427, etc., and those that impart a negative charge include
There are metal-containing complex salt dyes such as those shown in Publication No. 26478 and the like. However, these dyes and pigments used as charge control agents have complex structures and lack stability, and are susceptible to decomposition or deterioration due to, for example, mechanical friction and impact, changes in temperature and humidity conditions, electrical impact, and light irradiation. Therefore, charge controllability is likely to be lost. One qualitative flaw is that since it is a colored material, it violates the requirement that a charge control agent that can be considered colorless or substantially colorless is required for toners with a specific hue. be. Recently, Japanese Patent Application Laid-Open No. 53-127726, Japanese Patent Application Laid-open No. 57-104940,
Various complex compounds are disclosed in JP-A-57-111541, JP-A-57-124357, JP-A-59-79256, JP-A-59-88745, etc.;
However, some coloring cannot be avoided. The present inventors found that the dispersibility with the resin component is good,
In addition, it is a colorless substance that is thermally stable up to a temperature that is sufficient for melt kneading, and has excellent transparency, so-called three primary color toners (cyan, cyan,
As a result of extensive research into compounds that are less likely to cause color disturbances when incorporated into toners of various colors including magenta and yellow, and can impart a negative charge to toners, we have found that even if there are substituents, The present invention was completed based on the discovery that zinc complex compounds of aromatic oxycarboxylic acids are particularly excellent. The present invention provides an acid group of an aromatic oxycarboxylic acid selected from the group consisting of the following general formula K1217 (wherein A and A' are K1218 K1219 K1220 K1221 [(r) represents an alkyl group or a halogen atom, and n represents 0 or an integer from 1 to 4.]
M represents hydrogen, an alkali metal, NH ₄ or ammonium of an amine. ) A toner for developing an electrostatic image is characterized by containing at least one compound represented by the following. Examples of aromatic oxycarboxylic acids that may have substituents that can form the zinc complex compound according to the present invention include alkyl ( _C4 - _C9 ) salicylic acid, 3,
5-dialkyl ( _C4 - _C9 ) salicylic acid, 2-hydroxy-3-naphthoic acid, alkyl ( _C4 - _C9 )
-2-hydroxy-3-naphthoic acid, 5,6,
7,8-tetrahalogen-2-hydroxy-3-
Examples include naphthoic acid. The zinc complex compound represented by the general formula () according to the present invention can be synthesized by the following method. Add sufficient alkali to the oxycarboxylic acid and dissolve it in water, add a zinc metallizing agent at a molar ratio of 1:2, heat, adjust the PH, carry out the reaction, and collect the precipitate by filtration. Wash thoroughly with water and dry. The counter ion M in this case can be changed depending on the post-treatment conditions of the product. For example, the PH before filtration should be 3 or less, and the PH after filtration should be 6.
If you wash it until it reaches the ~7th position, the counter ion will be a hydrogen ion, and if you make the pH neutral to alkaline with an alkali, it will become an alkali metal ion, and if you further treat it with hydrochloride of various amines, you will get various ammonium ions. Salt is obtained. Incidentally, the amount of the complex compound represented by the general formula () added to the toner component is generally 0.1 to 10 parts by weight, preferably 0.5 parts by weight, based on 100 parts by weight of the resin.
It is contained in a proportion of ~5 parts by weight. In addition to the complex compound represented by the above general formula (), the toner of the present invention is made of styrene resin, styrene-acrylic resin, styrene-butadiene resin, epoxy resin, etc. ,
One or a mixture of known toner resins such as polyester resin and paraffin wax can be used. In addition, as coloring agents, there are many known dyes,
Pigments can be used, and those that are particularly excellent as toners for color copying include benzidine yellow, quinacridone, copper phthalocyanine blue, and copper phthalocyanine green. The toner of the present invention is usually mixed with a carrier to provide a two-component developer, but it can of course also be used as a one-component developer. A manufacturing example is shown below. Production Example 1 (Synthesis of zinc complex compound of 2-hydroxy-3-naphthoic acid) 2-hydroxy-3-naphthoic acid 42.2gr (0.22gr)
mol) in 500g of 2.7% caustic soda aqueous solution and raise the temperature to approximately 70℃. Then add 35.5gr (0.13mol) of zinc sulfate to 100gr of water
Dissolve in water and drip over 30 minutes. Maintain at 70-80°C for 2 hours, adjust pH to 7.0±0.5, and complete the reaction.
It was filtered while hot, washed with water, and dried to obtain 47.5 gr of a pale yellow fine powder complex compound (counterion Na, hereinafter this complex compound will be referred to as compound (1)). Production Example 2 (Synthesis of zinc complex compound of 3,5-ditertyabutylsalicylic acid) 44.4 gr of 3,5-ditertyabutylsalicylic acid
(0.18 mol) was completely dissolved in 400g of 2% aqueous sodium hydroxide solution, and the temperature was raised to about 70°C. Then add 25.5gr (0.09mol) of zinc sulfate to 100gr of water
Dissolve in water and drip over 30 minutes. Maintain at 70-80°C for 2 hours, adjust pH to 7.0±0.5, and complete the reaction.
It was filtered while hot, washed with water, and dried to obtain 43gr of a white fine powder complex compound (counterion Na, hereinafter this complex compound will be referred to as compound (2)). Production Example 3 (Synthesis of zinc complex compound of tertiary butyl-2-hydroxy-3-naphthoic acid) Completely dissolve 12.2 gr (0.05 mol) of tertiary butyl-2-hydroxy-3-naphthoic acid in 200 gr of 2% aqueous sodium hydroxide solution. and raise the temperature to approximately 70℃. Next, 3.4 gr (0.025 mol) of zinc chloride is dissolved in 100 gr of water and added dropwise over 30 minutes. Keep at 70-80℃ for 2 hours,
Adjust the pH to 7.0±0.5 and terminate the reaction. After filtering while hot, washing with water, and drying, the complex compound becomes a pale yellow fine powder.
13.1gr was obtained (counter ion Na, hereinafter this complex compound will be referred to as compound (3)). Production Example 4 (Synthesis of zinc complex compound of salicylic acid and 3,5-ditertyabutylsalicylic acid) 6.9 g (0.05 mol) of salicylic acid and 12.5 g (0.05 mol) of 3,5-ditertyabutylsalicylic acid at 2%
Completely dissolve in 200g of caustic soda aqueous solution and raise the temperature to approximately 70℃. Next, add 3.4g (0.025mol) of zinc chloride to water.
A solution of 100 g was added dropwise to the above aqueous solution over 30 minutes, and the mixture was stirred at 70 to 80°C for 2 hours. Add an aqueous hydrochloric acid solution to this to adjust the pH to 3.5 and complete the reaction. This was filtered while hot, washed with water, and dried to obtain 19.9 g of a white fine powder complex compound (counter ion: hydrogen,
This complex compound will be referred to as Compound Example (4) below. ) Production Example 5 After reacting in the same manner as in Production Example 4, the reaction was terminated by treatment with 4.5 g (0.04 mol) of diethanolamine. This was then filtered while hot, washed with water, and dried to obtain 23.4 g of a white complex compound (counter ion: ammonium of diethanolamine, hereinafter this complex compound will be referred to as compound example (5)). Compound example (4) and (5) and examples of zinc complex compounds synthesized according to the above production example are shown in Table 1. In addition,
In Table 1, Bt represents a tertiary butyl group.

【table】

[Table] Examples are shown next. In addition, in the examples,
"Parts by weight" is abbreviated as "parts". Example 1 Polyester resin...100 parts (manufactured by Kao Soap Co., Ltd., ATR-2010) Blue dye...2 parts (manufactured by Orient Chemical Industry Co., Ltd., Valifast, Blue
2606) Blue pigment...4 parts (copper phthalocyanine) Compound (1)...1 part The above mixture was uniformly premixed in a ball mill,
Prepare premixes. Next, the mixture was melt-kneaded using hot rolls, cooled, and then coarsely ground using a vibration mill, and further finely ground using an air jet mill. The obtained fine powder was classified to obtain a blue toner having a particle size of 10 to 20 μm. A developer was prepared by mixing 97 parts of iron powder carrier with 3 parts of the obtained toner. The initial blow-off charge amount of this developer was -28.3 μC/gr. When a toner image was formed using this developer on a commercially available selenium drum using a magnetic brush development method, a clear blue image without fogging was obtained. This toner is suitable for continuous copying.
No deterioration in copy quality was observed even after 50,000 copies. Example 2 Epoxy resin...100 parts (manufactured by Ciel Chemical Co., Ltd., Epicoat 1004) Carbon black...6 parts Compound (2)...2 parts The above formulation was treated in the same manner as in Example 1 to prepare a black toner. . A developer was prepared by mixing 97 parts of iron powder carrier with 3 parts of the obtained toner. The initial blow-off charge amount of this developer was -24.1 μC/gr. When copies were made using this developer in the same manner as in Example 1, clear black images without fog were obtained. This toner is
No deterioration in copy quality was observed even after continuous copying of 50,000 sheets. Example 3 Styrene-n-butyl methacrylate copolymer resin (65/35)...100 parts CISolvent Yellow77...6 parts Compound (1)...2 parts The above formulation was treated in the same manner as in Example 1 to create a yellow toner. adjusted. A developer was prepared by mixing 97 parts of iron powder carrier with 3 parts of the obtained toner. The initial blow-off charge amount of this developer was -25.2 μC/gr. When copies were made using this developer in the same manner as in Example 1, images with no fog and excellent fine line reproducibility were obtained. With this toner, no deterioration in copy quality was observed even after 50,000 continuous copies were made. Example 4 Styrene-n-butyl methacrylate copolymer resin (65/35)...100 parts Red dye...8 parts (manufactured by Orient Chemical Industry Co., Ltd., Valifast Pink
2310) Compound (2)...2 parts The above formulation was treated in the same manner as in Example 1 to prepare a red toner. A developer was prepared by mixing 97 parts of iron powder carrier with 3 parts of the obtained toner. The initial blow-off charge amount of this developer was -22.9 μC/gr. When copies were made using this developer in the same manner as in Example 1, clear red images without fog were obtained. This toner is
No deterioration in copy quality was observed even after continuous copying of 50,000 sheets. Example 5 Styrene-n-butyl methacrylate copolymer resin (65/35)...100 parts CISolvent yellow77...6 parts Compound (3)...2 parts The above formulation was treated in the same manner as in Example 1 to create a yellow toner. adjusted. A developer was prepared by mixing 97 parts of iron powder carrier with 3 parts of the obtained toner. The initial blow-off charge amount of this developer was -21.8 μC/gr. When copies were made using this developer in the same manner as in Example 1, clear yellow images without fog were obtained. This toner is
No deterioration in copy quality was observed even after continuous copying of 50,000 sheets. Example 6 Styrene-n-butyl acrylate copolymer resin (65/35)...100 parts CISolvent Yellow77...1 part Compound example (4)...1 part The above formulation was treated in the same manner as in Example 1 to give it a yellow color. A toner was prepared. A developer was prepared by mixing 97 parts of iron powder carrier with 3 parts of the obtained toner. The initial blow-off charge amount of this developer was -20.2. When copies were made in the same manner as in Example 1 using this developer, clear yellow images without fog were obtained. Example 7 Styrene-n-butyl acrylate copolymer resin (65/35) ...100 parts pink dye (manufactured by Orient Chemical Industry Co., Ltd., Oil
Pink312 [trade name])...2 parts Compound example (5)...1.5 parts The above formulation was treated in the same manner as in Example 1 to prepare a magenta toner. A developer was prepared by mixing 97 parts of iron powder carrier with 3 parts of the obtained toner. The initial blow-off charge amount of this developer was -20.0. When copies were made in the same manner as in Example 1 using this developer, clear magenta images without fog were obtained. Comparative Example 1 A developer was prepared in the same manner as in Example 6, except that Compound Example (4) used in Example 6 was replaced with a compound represented by the following formula (pale bluish green). In addition, in the following formula, Bt represents a tertiary butyl group. K1236 When copies were made in the same manner as in Example 1 using this developer, color tone disturbances were observed. Comparative Example 2 A developer was prepared in the same manner as in Example 7, except that Compound Example (5) used in Example 7 was replaced with a compound represented by the following formula (light yellowish green). K1237 When copying was carried out in the same manner as in Example 1 using this developer, no clear magenta image was obtained. Color Density Test 500g of polystyrene resin and a metal complex compound of each aromatic oxycarboxylic acid using those shown in Table 2 below as the central metal in general formula () were premixed, and then 200g of polystyrene resin was mixed with an injection molding machine.
It was molded at ℃ to create a molded plate with a width of 60 mm, a height of 50 mm, and a thickness of 3 mm. The reflection density (Dr) of the molded plate was measured using a Macbeth transmission-reflection densitometer TR-927 (trade name, manufactured by Kollmorgen), and the results are shown in Table 2 below.

[Table] As is clear from Table 1, when the zinc complex compound of aromatic oxycarboxylic acid, which is the charge control agent in the toner of the present invention, is added to the resin used in the toner, It is very pale in color compared to chromium or cobalt complex compounds.
Excellent for avoiding toner color tone disturbances. On top of that,
The reflection density when passing through each of the red, green, and blue filters is also low, and the variation thereof is very small, which is effective in preventing adverse effects on the spectral characteristics of the toner.

Claims (1)

[Scope of Claims] 1 The following general formula K1212 (wherein A and A' are residues of an aromatic oxycarboxylic acid selected from the group consisting of K1213 K1214 K1215 K1216 [(r) represents an alkyl group or a halogen atom] and n represents 0 or an integer of 1 to 4.]
M represents hydrogen, an alkali metal, NH ₄ or ammonium of an amine. ) A toner for developing an electrostatic image, comprising at least one compound represented by the following. 2 Claim 1 containing resin and colorant
Toner for developing electrostatic images as described in Section 1. 3. The toner for developing electrostatic images according to claim 2, wherein the compound represented by the general formula () is contained in an amount of 0.5 to 5 parts by weight based on 100 parts by weight of the resin.