JPH0228144B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a toner for developing electrostatic latent images in electrophotography, electrostatic recording, and the like. In electrophotography, a latent image is formed on a photoconductor made of a photoconductive substance, which is developed with a powder developer to become a visible image, and then transferred onto paper using heat, solvent, or in some cases pressure. The most common method is to establish As a developer for such electrophotography, a mixture of a fine particle powder called developer powder or toner, which is made of a resin and a colorant, and a carrier, such as minute glass beads or iron powder, is used.
In this case, a developer using extremely fine ferrite or magnetite as a carrier is called a -component developer, and can be distinguished from the former. The present invention relates to developer powder called toner of these developers. The photoconductor layer can be positively or negatively charged so that exposure under the original produces a positive or negative electrostatic latent image. Therefore, a positively charged positive image is generated on the negative electrostatic latent image. However, when a positively electrostatic latent image is developed with negatively charged developer powder, the black and white tones are reversed and a negative image of the original, that is, a positive negative image is obtained. As described above, there are two types of developer powder for electrophotography: positively charged developer powder and negatively charged developer powder. The present invention relates to negatively charged developer powder. Generally, developer powder is a fine powder made by mixing synthetic resin with coloring agents such as dyes and pigments. In order to charge the developing powder negatively, the dye mixed therein plays an important role not only in coloring but also in its electrostatic properties as a charge control agent. In particular, most of the dyes and pigments conventionally used as coloring agents are positively charged, and even if they are negatively charged, their chargeability is weak, resulting in mixed mirror images or fog, resulting in sharp images. I couldn't get an image. The present inventors focused on this point and developed a dye that has negative characteristics and particularly has extremely good compatibility with the resin used. As a result, it was possible to produce a developing powder with excellent electrostatic properties that improved all the drawbacks of conventionally used colorants. That is, the present invention provides the following formula (In the formula, X ₁ and X ₂ are hydrogen atoms, lower alkyl groups,
represents a lower alkoxy group, nitro group or halogen atom, n represents 1 or 2, m represents an integer of 1 to 3, n, m and X ₁ , X ₂ may be the same or different, M represents a chromium atom or a cobalt atom, and A represents an aliphatic ammonium ion (including substituted aliphatic ammonium ions), an alicyclic ammonium ion, or a heterocyclic ammonium ion. This is an electrophotographic developing powder containing a metal complex salt compound represented by ) as a charge control agent and a coloring agent. The above-mentioned metal complex salt compound has the property of being electrostatically negatively charged, and therefore, by mixing it with a suitable developing resin in a desired ratio, a negatively charged developing powder can be obtained very easily. In addition, there are many metal complex salt compounds similar to the compound represented by the above formula (1) as colorants for toner, as detailed below, but the compound according to the present invention is more suitable for developing powder than known compounds. It has particularly good compatibility with resins. Therefore, the developer powder is uniformly distributed in each of the fine particles. This is an important point regarding the charging characteristics of the developing powder. Furthermore, the dye of the present invention itself has an extremely large amount of negative charge. Regarding electrophotographic toners containing metal complex compounds, for example, Japanese Patent Publication No. 1973-20153, Japanese Patent Publication No. 43
-17955 and Japanese Patent Publication No. 43-27596, etc., the toner containing the metal complex compound represented by the general formula (1) of the present invention has a higher chargeability than those described in these publications. It also shows a negative result in a mutagenicity test (Ames test), making it suitable as a toner for electrophotography. On the other hand, the inventors have already developed an electrophotographic toner containing a metal complex compound as a similar compound.
57-141452, but compared to that invention, the present invention is due to the chemical structure of the counter ion,
It has extremely good compatibility or solubility with various resins that are the main binders of toners, so when used as an additive in electrophotographic toners, it has excellent charging stability during continuous toner copying. Moreover, since the coloring power is high, the copied image becomes extremely clear, and it is possible to obtain a copy with excellent gradation. The metal complex salt compound of the present invention was first developed in JP-A-57-
According to the description in Publication No. 141452, the following formula (In the formula, X ₁ , X ₂ , n, m and M are as defined in the above formula (1).) It can be easily obtained by salt formation treatment with aliphatic amines (including substituted aliphatic amines), alicyclic amines, or heterocyclic amines. Examples of amines that can be suitably used in the above salt-forming treatment include compounds represented by the following general formulas (3) and (4). (In the formula, R ₁ , R ₂ , R ₃ are hydrogen atoms, alkyl groups, halogen atoms, hydroxyl groups, alkoxy groups, amino groups, alkyl-substituted amino groups, phenyl groups, naphthyl groups, alkyl groups substituted with heterocyclic groups) , is an alkenyl group, and R ₁ and R ₂ form a ring via a nitrogen atom, or can further contain a hetero atom and form a ring via a nitrogen atom, and R ₁ , R ₂ , R ₃ may be the same or different.However, cases in which R ₁ , R ₂ , and R ₃ are all hydrogen atoms are excluded.) (In the formula, R ₄ , R ₅ , R ₆ , and R ₇ are alkyl groups or alkyl groups substituted with halogen atoms, hydroxyl groups, alkoxy groups, amino groups, alkyl-substituted amino groups, phenyl groups, naphthyl groups, and heterocyclic groups. , is an alkenyl group, R ₁ and R ₂ can form a ring via a nitrogen atom, or can further contain a hetero atom and form a ring via a nitrogen atom,
R ₄ , R ₅ , R ₆ and R ₇ may be the same or different, and Y represents a residue of an onium compound such as a halogen atom or a sulfonic acid group. ) More specifically, for example, the compounds shown below can be mentioned.

【formula】

【formula】

【formula】

【formula】

【formula】 In addition to the metal complex compound, the toner of the present invention also contains:
The toner of the present invention contains a binding substance and a coloring substance, and examples of binding substances that can be suitably used in the toner of the present invention include monomers of styrene and its substituted products such as polystyrene and polyvinyltoluene, styrene-substituted styrene copolymers, Styrene-acrylic ester copolymer, styrene-methacrylic ester copolymer, styrene-acrylonitrile copolymer,
Polyvinyl chloride, polyethylene, silicone resin, polyester, polyurethane, polyamide,
Epoxy resins, modified rosins, phenolic resins, etc. can be used alone or in combination. Examples of coloring substances include CI Pigment Yellow 12, CI Solvent Yellow 16, CI Disperse Yellow 33, CI Pigment Red 122,
CI Solvent Red 19, CI Pigment Blue
15, CI Pigment Black 1, CI Solvent Black 3, CI Solvent Black 22, Carbon Black, etc. can be used. Another feature of the present invention is that by using it in combination with a colored dye that has the effect of a conventionally known charge control agent, the drawback of lack of long-term stability of known charge control agents can be significantly improved. Hereinafter, the present invention will be explained in detail with reference to Examples, where parts are parts by weight. Example 1 Synthesis of metal complex compound; 19.9 parts of 4,6-dinitro-2-aminophenol was stirred with 10 parts of concentrated hydrochloric acid and 400 parts of water, cooled on ice to 0-5°C, and added with sodium nitrite.
6.9 parts were added and stirred at the same temperature for 2 hours to diazotize. This diazotide was mixed with 300 parts of water at 0 to 5°C, and 10
After a coupling reaction, a monoazo compound having the following structural formula was isolated. Dissolve this monoazo compound paste in 150 parts of ethylene glycol, add 5 parts of sodium hydroxide and 17.4 parts of sodium chromium salicylate, stir at 110-120°C for 2 hours to perform chromation, and then cool to room temperature. The precipitated product was filtered and the isolated wet cake was again dispersed in 400 parts of water. Next, a solution of 9.4 parts of 2-ethylhexyloxypropylamine, 5.2 parts of concentrated hydrochloric acid, and 50 parts of water was added, stirred for 1 hour at 40 to 50°C, the product was isolated by filtration, and dried under reduced pressure at 50 to 60°C. Thus, 58 parts of a fine black powder chromium complex compound represented by the following formula was obtained. When this chromium complex salt compound was dissolved in dimethylformamide, it exhibited a black color (maximum absorption wavelength 576 nm). Manufacture of toner: Add 7 parts of carbon black and 1.2 parts of the chromium complex compound synthesized above to 100 parts of styrene-acrylic copolymer resin, mix well, melt by heating, cool, and grind in a ball mill to form a negatively charged fine powder. A developing powder was obtained. Next, this developing powder was mixed with iron powder having a diameter of 100 to 150 μm at a weight ratio of 5:100 to obtain a developer. Next, an electrostatic latent image is formed on a selenium photosensitive plate charged by corona discharge (+5000V), and this positive image is transferred to paper and fixed by heat to create a clear image with no fog and clear halftones. Even after the 90,000th continuous copying (running), there was almost no change in the development characteristics of the toner, and the same good quality as the initial image was obtained. In addition, the amount of charge on the toner was measured using the blow-off method, and the initial charge was -23.0μc/
The charge amount of the toner at the 90,000th sheet of running was -22.5 μc/g, which was almost the same as the initial value, and the charge distribution was -22.4 to -.
It was almost uniform at 23.2 μc/g, and all were extremely excellent as toners. Next, as a comparative example, when the following known metal complex compound described in JP-A-57-141452 was used instead of the metal complex compound of the present invention, In particular, in continuous copying, it was possible to obtain clear images without any change in development characteristics from the initial to the 30,000th copy, but at the 90,000th copy, the amount of charge on the toner decreased compared to the initial value (-21.2μc/g). Significantly lower (−
15.3 μc/g), and at the same time, the image became unclear with background stains. Examples 2 to 10 Metal complex salt compounds were synthesized according to Example 1, and toners were obtained by the same operation as Example 1 with the developer composition shown in the following table. They are summarized in the table.

【table】

【table】

【table】

【table】

【table】

【table】

【table】

【table】

【table】

【table】

【table】

[Table] Example 11 Synthesis of metal complex compound; Dissolve the paste of the monoazo compound synthesized in Example 1 in 150 parts of ethylene glycol, then add 10 parts of concentrated sulfuric acid and 54 parts of 40% chromium sulfate aqueous solution, After chromating by stirring at 100°C for 3 hours, a paste of the following monoazo compound synthesized on a 0.1 molar scale according to Example 1 was added, 12 parts of sodium hydroxide and 11 parts of sodium acetate were added and stirred at 95-100°C for 2 hours to produce an asymmetric 1:2 type chromium complex salt compound, and the precipitated product was filtered at room temperature to form an isolated wet cake. was again dispersed in 800 parts of water. Next, a solution of 19 parts of 2-ethylhexyloxypropylamine dissolved in 11 parts of concentrated hydrochloric acid and 100 parts of water was added, stirred at 40-50°C for 1 hour, and the product was isolated by filtration, and the product was isolated under reduced pressure at 50-60°C. After drying, 120 parts of a black fine powder chromium complex compound represented by the following formula was obtained. When this chromium complex salt compound was dissolved in dimethylformamide, it exhibited a black color (maximum absorption wavelength 579 nm). Manufacture of toner: Using this chromium complex salt compound, the same treatment as in Example 1 was carried out to obtain a developer. Next, a positive electrostatic latent image is formed on a selenium photosensitive plate charged by corona discharge (+5000V), and this positive image is transferred to paper and heat-fixed to create a clear halftone image without fogging. Clear images can be obtained, and continuous copying (running)9
Even after the 10,000th copy, there was almost no change in the development characteristics of the toner, and a good copy that was the same as the initial image was obtained. In addition, the amount of charge on the toner was measured using the blow-off method, and the initial charge
The charge amount of the toner at the 90,000th sheet of running is -21.0μc/g, which is almost the same as the initial value, and the charge distribution is -21.0 ~
-21.4 μc/g, which was almost uniform, and all were extremely excellent as toners. By using the metal complex salt compound shown below instead of the chromium complex salt compound of Example 11, an extremely excellent toner could be obtained in the same manner as in Example 11. Example 12 Example 13

Claims (1)

[Claims] 1. The following general formula [In the formula, X ₁ and X ₂ are hydrogen atoms, lower alkyl groups,
represents a lower alkoxy group, nitro group or halogen atom, n represents 1 or 2, m represents an integer of 1 to 3, n, m and X ₁ , X ₂ may be the same or different, M represents a chromium atom or a cobalt atom, A represents an aliphatic ammonium ion (including substituted aliphatic ammonium ions),
Represents an alicyclic ammonium ion or a heterocyclic ammonium ion. ] An electrophotographic toner comprising a metal complex compound represented by: