JP2001154413A - Electric charge adjusting agent and electrostatic charge image developing negative charge type toner using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric charge adjusting agent not containing a harmful compound of a heavy metal or the like, applicable to any of black and color toners because of its slightly colored state and excellent in electrostatic charge characteristics (in particular, electrostatic charge build-up property and aging stability) and an electrostatic charge image developing negative charge type toner containing the electric charge adjusting agent. SOLUTION: The electric charge adjusting agent is of a negative charge type and the negative charge type toner comprises a compound of formula I (where R1-R4 are each H or alkyl, R1 and R2 may bond to each other to form an aromatic ring or a heterocycle and R3 and R4 may bond to each other to form an aromatic ring or a heterocycle).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charge control agent used to control the chargeability of an electrophotographic toner, and a negative charge toner for developing an electrostatic image using the same.

[0002]

2. Description of the Related Art In copiers and printers utilizing the principle of electrophotography, an electrostatic latent image is formed on a photoconductor composed of an inorganic photoconductor such as selenium or an organic photoconductor such as polyvinylcarbazole. Is formed, and a dry toner charged in advance is supplied thereto to form a visible image.

A dry toner used for developing an electrostatic latent image is a one-component type toner in which a magnetic powder such as iron powder is internally added, and a dry toner which is a mixture of toner particles and a magnetic powder. They are roughly divided into those based on components. In the case of a one-component system, due to friction between toner particles, and in the case of a two-component system,
The toner particles are mixed and stirred with the magnetic powder to charge the surface of each toner particle. The quality of electrostatic printing is greatly influenced by the charging characteristics of the toner particles (for example, charging startability, charging stability over time, saturation charge amount, etc.). Therefore, these physical properties are controlled and always used in a stable state. For this reason, a charge control agent having a positive charge or a negative charge is often added internally when producing toner particles.

Conventionally, an azo-based metal chelate complex is disclosed in Japanese Patent Publication No. 2-16916 and the like, and salicylic acid and its derivative are disclosed in Japanese Patent Publication No. 2-60183 as a charge control agent for imparting a negative charge to a toner. The system chelate complex
JP-B-7-13765 and the like have proposed benzylic acid-based chelate complexes.

[0005] Among these, azo metal chelate complexes are colored and cannot be applied to color toners. In addition, due to their structure, they often contain heavy metals, and there is a concern that they may affect the environment. Further, azo metal chelate complexes are:
There is a problem that the charge control agent is decomposed or deteriorated due to mechanical shock at the time of kneading the toner or temperature and humidity conditions, and the original function of the charge control agent is reduced.

On the other hand, among salicylic acid, its derivative-based chelate complexes and benzylic acid-based chelate complexes, in particular, boron-based chelates themselves are colorless or pale-colored compounds, and are often used as negatively chargeable charge control agents for color toners. Although it is applied, there are still problems in charging stability to temperature and humidity changes, stability over time, crystal grain size when kneaded and dispersed in the toner resin, and the like. Since it is expensive, it can be applied only to color toner.

Further, US Pat. No. 5,238,768 discloses that bisphenol S is used as a negatively chargeable charge control agent. This compound is used when kneading with a toner resin. It is almost completely compatible (dissolved) with the toner resin (polyester resin or styrene / (meth) acrylic resin). Therefore, no effect is exhibited unless the addition ratio as the charge control agent is set relatively high. There was a problem.

[0008]

As described above, no inexpensive and versatile charge control agent which is colorless or pale in color, contains no harmful heavy metals, has excellent charging characteristics, and has not been found yet. Is the current situation. The problem to be solved by the present invention is that it contains no harmful heavy metals, has little coloring,
An object of the present invention is to provide a charge control agent which can be applied to any toner regardless of color and has excellent charging characteristics (particularly, charge rising property and stability over time) and a negatively chargeable toner for developing electrostatic images containing the same.

[0009]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that the general formula (I)

[0010]

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[0011] (wherein, R _1, R _2, R ₃ and R ₄ is, independently, a represents a hydrogen atom or an alkyl group, R ₁ and R ₂
And R ₃ and R ₄ may combine to form an aromatic ring or a heterocyclic ring. It has been found that the above problems can be solved by applying the compound represented by the formula (1) as a negatively chargeable charge control agent, and the present invention has been completed.

That is, the present invention provides (1) a negatively chargeable charge control agent comprising a compound represented by the general formula (I) in order to solve the above-mentioned problems.

According to another aspect of the present invention, there is provided (2) a toner containing a toner resin, a colorant, and a charge control agent, wherein the charge control agent is a negative charge control agent as described in (1) above. Provided is a negatively chargeable toner for developing an electrostatic image using an agent.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The compound represented by the general formula (I) of the present invention is obtained by converting 4,4'-diaminodiphenylsulfone and a corresponding dicarboxylic anhydride with toluene and / or xylene and N, N'-. In a mixed solvent system with dimethylacetamide, it can be easily produced by reacting while azeotropically removing water generated in the dehydration reaction.

The dicarboxylic anhydride used for synthesizing the compound represented by the general formula (I) is not particularly limited. For example, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, succinic anhydride, Maleic anhydride, hymic anhydride, heptic anhydride, trimellitic anhydride, and the like. Among these, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, and succinic anhydride are particularly preferred.

The dicarboxylic anhydride used in the synthesis of the compound represented by the general formula (I) of the present invention does not necessarily have to be selected one kind at the time of the reaction, but may be a mixture of two or more kinds. It can also be done.

Representative examples of the compound represented by the general formula (I) of the present invention include compounds represented by the following formulas (1) to (10).

Equation (1)

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Equation (2)

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Equation (3)

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Equation (4)

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Equation (5)

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Equation (6)

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Equation (7)

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Equation (8)

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Equation (9)

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Equation (10)

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In the present invention, there is no particular limitation on the method of internally adding the charge control agent to the toner. For example, the compound represented by the general formula (I) used as the charge control agent is preliminarily pulverized, and if necessary, After further classification, a method of mixing and melt-kneading the pulverized product together with a toner resin, a colorant, and other components of the toner may be used.

When the charge control agent of the present invention is internally added to the toner, the amount of addition is 0.1 to 100 parts by weight of the toner resin.
A range of 1 to 15 parts by weight is preferred, and a range of 1 to 10 parts by weight is particularly preferred. If the use ratio of the charge control agent is less than 0.1 part by weight, it is not preferable because the rising property at the time of charging is deteriorated or the toner tends to be easily scattered. On the other hand, when the use ratio of the charge control agent is 15
When the amount is more than the weight part, the charge amount of the toner when frictionally charged tends to decrease with time, and the charge stability tends to deteriorate, which is not preferable.

The toner of the present invention may be used in combination with other charge adjusters as long as the performance of the charge adjuster and the intended use of the toner are not impaired.

As the toner resin (binder resin) used in the toner of the present invention, any conventionally known toner resin used for electrophotography can be used, and there is no particular limitation. As such a toner resin, for example, polystyrene,
Styrene / (meth) acrylate copolymer, styrene / (meth) acrylate / acrylonitrile copolymer, styrene / butadiene copolymer, styrene /
Styrene resins such as vinyl chloride copolymer, styrene / maleic acid copolymer, polyester resin, epoxy resin,
(Meth) acrylic resin, phenolic resin, xylene resin, vinyl chloride resin, polyurethane resin, polyvinyl butyral resin, and the like.
Styrene / (meth) acrylate resin and polyester resin are particularly preferred. Usually, one kind of these resins is used, but two or more kinds can be used in combination as needed.

As the colorant used in the toner of the present invention, various conventionally known organic pigments, inorganic pigments, dyes and the like can be used. Specific examples of the colorant include black pigments such as carbon black and run black; blue pigments such as phthalocyanine blue, aniline blue and ultramarine blue; green pigments such as malachite green, phthalocyanine green and brilliant green; rose bengal and permanent red And red pigments such as Irgasin Red and Toluidine Red; yellow pigments such as Benzidine Yellow, Quinoline Yellow, First Yellow G and Hansa Yellow; triarylmethane dyes, azo dyes and nigrosine dyes.

In addition to the above, conventionally known additives such as higher fatty acids or metal salts thereof, and natural or synthetic waxes may be added to the toner of the present invention, if necessary.

The negatively chargeable toner of the present invention can be applied to both a two-component developer and a one-component developer.

When the toner of the present invention is used as a two-component developer, the toner is mixed with a carrier powder, and the carrier powder used at that time is, for example,
Examples thereof include magnetic powders such as iron powder, ferrite powder and nickel powder, glass beads, and the like, as well as coating carriers whose surfaces are treated with a resin.

When the toner of the present invention is used as a one-component developer, a suitable amount of magnetic fine powder such as iron powder and ferrite powder is added and dispersed during the production of the toner.
Alternatively, it is used in the form of a non-magnetic single component containing no magnetic powder.

[0037]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. In the following Examples and Comparative Examples, “parts” and “%” are all based on weight unless otherwise specified.

(Synthesis Example 1) Reflux condenser, thermometer, Dea
n Stark trap and a 1-liter four-necked flask equipped with a stirrer were charged with 80 g of 4,4'-diaminodiphenylsulfone, 96 g of phthalic anhydride, 300 g of xylene and 100 g of N, N'-dimethylacetamide.
g. Next, the contents were heated to the reflux temperature with stirring, and at the same temperature, the imidization reaction was continued until water ceased, while removing generated water by azeotropic distillation with xylene. After completion of the reaction, the precipitated particulate compound was filtered under reduced pressure, washed with toluene, and dried under reduced pressure at 120 ° C. for 3 hours to obtain the compound represented by the formula (1).

Synthesis Example 2 A compound represented by the formula (2) was obtained in the same manner as in Synthesis Example 1 except that 68 g of succinic anhydride was used instead of phthalic anhydride. .

(Synthesis Example 3) A compound represented by the formula (3) was obtained in the same manner as in Synthesis Example 1 except that 100 g of hexahydrophthalic anhydride was used instead of phthalic anhydride. Was.

Synthesis Example 4 A compound represented by the formula (4) was obtained in the same manner as in Synthesis Example 1 except that 99 g of tetrahydrophthalic anhydride was used instead of phthalic anhydride. Was.

(Comparative Synthesis Example 1)
Instead of 4'-diaminodiphenylsulfone, 1,4-
Except that 34 g of phenylenediamine was used, the formula (11) was obtained in the same manner as in Synthesis Example 1.

[0043]

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A compound represented by the following formula was obtained.

For each compound obtained in Synthesis Examples 1 to 4 and Comparative Synthesis Example 1, a TG-DTA measuring device (manufactured by Rigaku Corporation)
Melting point measured by using GCMS9100-
Table 1 shows the results of mass spectra measured using MS (manufactured by Shimadzu Corporation).

[0046]

[Table 1]

(In the above table, M ⁺ represents the molecular ion of the fragment.)

Example 1 2 parts of the compound represented by the formula (1) obtained in Synthesis Example 1, a polyester resin for toner (glass transition temperature (Tg) = 65.6 ° C., acid value ≒ 10, weight average molecular weight) (Mw) ≒ 10,000, number average molecular weight (M
n) $ 4,800) 100 parts, carbon black (MA-100 manufactured by Mitsubishi Chemical Corporation) 5 parts and polypropylene wax (Viscol 550 manufactured by Sanyo Chemical Industry Co., Ltd.)
P ") 2 parts were premixed using a Henschel mixer,
Next, the mixture was melt-kneaded using a heated roll mill, cooled to room temperature, finely pulverized using a jet mill, and classified to obtain a non-magnetic one-component toner as a powder having an average particle diameter of 10 μm.

Examples 2 to 4 In Example 1, each of the compounds represented by the formulas (2) to (4) obtained in Synthesis Examples 2 to 4 was replaced with the compound represented by the formula (1). A non-magnetic one-component toner was obtained in the same manner as in Example 1 except that the toner was used.

Comparative Example 1 In Example 1, the formula (1)
Example 1 was repeated except that the compound represented by the formula (11) obtained in Comparative Synthesis Example 1 was used instead of the compound represented by the formula
In the same manner as in the above, a non-magnetic one-component toner was obtained.

(Comparative Example 2) In Example 1, the formula (1)
In the same manner as in Example 1, except that 0.5 parts of “LR-147” (benzyl acid / boron chelate compound manufactured by Nippon Carlit Co., Ltd.) was used instead of the compound represented by the formula:
A non-magnetic one-component toner was obtained.

Comparative Example 3 In Example 1, the formula (1)
A non-magnetic one-component toner was obtained in the same manner as in Example 1 except that bisphenol S (hereinafter, referred to as “BPS”) was used instead of the compound represented by

(Comparative Example 4) In Example 1, the formula (1)
A non-magnetic one-component toner was obtained in the same manner as in Example 1 except that the compound represented by the following formula was not used.

(Evaluation Method of Toner) (A) Measurement of charge amount: 4 g of the toner obtained in each of Examples and Comparative Examples and 96 g of a ferrite carrier were put in a 100-ml capacity plastic bottle, and the plastic bottle was set on a ball mill. 1
After stirring at 20 rpm for 3 minutes, an E-spurt analyzer (“Model EST-I” manufactured by Hosokawa Micron Corporation) was used.
I)), the two-component sample was supplied, and the charge amount was measured for the following four items. The results are summarized in Tables 2 and 3. Q / d: average charge amount per unit diameter of toner particles (fe
m / C / 10 μm) Q / m; average charge amount per unit weight of toner particles (μ
C / g) Ratio of oppositely charged toner (%); ratio of positively charged toner in all toners Ratio of lowly charged toner (%);
Ratio of toner in the range of 0.5 to 0 μC / g

[0055]

[Table 2]

[0056]

[Table 3]

(B) Print test: Using the toner obtained in each example or each comparative example, using a commercially available non-magnetic one-component developing machine (“Ipsiocolor 2000” manufactured by Ricoh Co., Ltd.) A solid image print test was performed. The results are summarized in Tables 4 and 5.

(B-1) Print Rising Property The first sheet was visually inspected for print unevenness. : No unevenness (homogeneous image), good rise △: Weak unevenness, slightly unstable start up ×: Some unevenness, unstable start up

(B-2) Image Density The optical density (OD) of the solid printed image was measured with a Macbeth optical densitometer on the tenth sheet and the 10,000th sheet after the start of printing.

[0060]

[Table 4]

[0061]

[Table 5]

(Note: * indicates data of the 1000th sheet.)

Example 5 2 parts of the compound represented by the formula (1) obtained in Synthesis Example 1, 100 parts of the same polyester resin for toner as used in Example 1, and KET BL as a colorant
UE 106 (CIPig.No. B- made by Dainippon Ink and Chemicals, Inc.)
15-4) 5 parts and polypropylene wax (Sanyo Chemical Industries, Ltd.)
2 parts of "Viscol 550P" manufactured by K.K.) were premixed using a Henschel mixer, melt-kneaded using a heated roll mill, and then cooled to room temperature. This is finely pulverized using a jet mill and further classified to have an average particle size of about 1
A non-magnetic one-component toner was obtained as a 0 μm powder.

(Examples 6 and 7) In Example 5, instead of the compound represented by the formula (1) obtained in the synthesis example 1, the compound represented by the formula (2) obtained in the synthesis example 2 or 3 or A non-magnetic one-component toner was obtained in the same manner as in Example 5, except that the compound represented by the formula (3) was used.

(Comparative Example 5) In Example 5, the formula (1)
A non-magnetic one-component toner was obtained in the same manner as in Example 5 except that the compound represented by the following formula was not used.

For each of the non-magnetic one-component toners obtained in Examples 5 to 7 and Comparative Example 5, image quality was evaluated by a print test in the same procedure as in (B) of Example 1, and the results are shown in Table 6.
Are shown together.

[0067]

[Table 6]

(Note: * indicates data of the 1000th sheet.)

(Example 8) 2 parts of the compound represented by the formula (1) obtained in Synthesis Example 1, 100 parts of the same polyester resin for toner as used in Example 1, and KET RE as a colorant
D 309 (CIPig.No.R-1 manufactured by Dainippon Ink and Chemicals, Inc.)
22) 5 parts and polypropylene wax (Sanyo Chemical Industries, Ltd.)
2 parts of “Viscol 550P” manufactured by K.K.) were premixed using a Henschel mixer, melt-kneaded using a heated roll mill, and then cooled to room temperature. This is finely pulverized using a jet mill, and further classified to give an average particle size of about 10
A non-magnetic one-component toner was obtained as a μm powder.

(Examples 9 to 10) In Example 8, the compound represented by the formula (3) or the compound represented by the formula (4) obtained in Synthesis Example 3 or 4 is used instead of the compound represented by the formula (1). A non-magnetic one-component toner was obtained in the same manner as in Example 8 except that the above compound was used.

(Comparative Example 6) In Example 8, the formula (1)
A non-magnetic one-component toner was obtained in the same manner as in Example 8, except that the compound represented by the following formula was not used.

The image quality of the non-magnetic one-component toners obtained in Examples 8 to 10 and Comparative Example 6 was evaluated by the same printing test as in (B) of Example 1, and the results are shown in Table 7. Was.

[0073]

[Table 7]

(Note: The * mark indicates data on the 1000th sheet.)

[0075]

As described above, the diphenylsulfone compound used as the charge control agent of the present invention has some degree of compatibility with the toner resin because both ends of the molecule are substituted with imide groups. For example, there is an advantage that the effect as a charge control agent is more easily exerted than a completely compatible type compound such as bisphenol S. Therefore, when this compound is used as a charge control agent, a negatively chargeable toner having excellent charge rising property and charge stability over time can be provided. In addition, since the charge control agent of the present invention is almost colorless, when used in a color toner, color reproducibility is good and a clear color image can be obtained.

Accordingly, the charge control agent of the present invention is useful as a charge control agent for a negatively chargeable toner which has no coloring, and is excellent in charge rising property and charge aging stability.

Claims (3)

[Claims] 1. A compound of the general formula (I) (Wherein R ₁ , R ₂ , R ₃ and R ₄ each independently represent a hydrogen atom or an alkyl group, provided that R ₁ and R ₂ and R ₃ and R ₄ are bonded together. Which may form an aromatic ring or a heterocyclic ring). 2. The compound represented by the general formula (I) is a compound represented by the formula (1): A compound represented by the formula (2): A compound represented by the formula (3): Or a compound represented by the formula (4): The negatively chargeable charge control agent according to claim 1, which is a compound represented by the formula: 3. A toner containing a toner resin, a colorant and a charge control agent, wherein the negative charge control agent according to claim 1 or 2 is used as the charge control agent. Negatively chargeable toner.