JPH07120082B2 - Positively chargeable color toner - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positively chargeable color toner for developing an electrostatic latent image in electrophotography, electrostatic recording and the like.

[0002]

2. Description of the Related Art Conventionally, there is a nigrosine dye as a positive charge control agent used for a positively chargeable toner for developing an electrostatic image. However, since the nigrosine dye is black brown, it can be used for black toner, but it cannot be used for color toners such as red, magenta, cyan and yellow.

Colorless positive charge control agents used for color toners include quaternary ammonium salts, polyamine resins and the like, but all have poor dispersibility in binder resins and are inferior in chargeability to nigrosine dyes. .

Further, the toner is required to have fluidity due to its property, and therefore one or more fluidizing agents are attached to the surface of the toner. Such toner is iron powder or ferrite carrier. The development is carried out so as to maintain the optimum amount of charge required for the development by the combination with.

[0005]

Colloidal silica has been conventionally used as a fluidizing agent for such toner. However, since colloidal silica inherently possesses a strong negative chargeability, the toner using colloidal silica loses the positive charge amount originally given to the toner while being mixed and stirred with the carrier in the developing machine. As a result, problems such as capry and toner scattering at the time of development, and fluidizing agents of these accumulated in the developer tend to occur, such as shortening of the life of the developer.

Particularly, the chargeability of the color toner containing the quaternary ammonium salt and the polyamine resin is easily affected by the negative chargeability of the colloidal silica, and the decrease in the charge amount is more remarkable than that of the black toner containing the nigrosine dye. Therefore, fogging during development and toner scattering are likely to occur.

Further, when a toner having colloidal silica adhered to its surface is developed in a high temperature and high humidity environment, the toner is scattered due to the decrease in the charge amount due to the moisture absorption of the colloidal silica, which causes problems such as increased fog. On the contrary, in a low-temperature and low-humidity environment, there are problems that the image density is lowered and filing occurs due to an increase in the charge amount.

The present invention solves the above-mentioned problems caused by the addition of a fluidizing agent, and is free from the problems of reduction in image density, increase in background fog, poor gradation, and toner scattering without being affected by environmental characteristics. An object of the present invention is to provide a positively chargeable color toner capable of obtaining a large number of copies.

[0009]

SUMMARY OF THE INVENTION The present invention has been made as a result of intensive studies in view of the above situation, and the surface of toner particles containing a binder resin, a color colorant, and a quaternary ammonium salt as a main component. In addition, alumina particles treated with a coupling treatment agent having a CO ₂ gas adsorption number of 4.0 / nm ² or less and a BET specific surface area of 80 m ² / g or more were added to the toner particles in an amount of 0. .01-
The present invention relates to a positively chargeable color toner characterized by being adhered at 1.0% by weight.

Alumina particles, which are a feature of the present invention, are ultrafine particles of alumina produced by high-temperature (flame) hydrolysis of anhydrous aluminum chloride, the surface of which is treated with a coupling treatment agent. The number of CO ₂ gas adsorption is 4.0 / nm ² or less and the specific surface area by BET method is 80 m ² / g or more. The number of CO ² gas adsorption and the specific surface area by the BET method can be adjusted by selecting the alumina fine particles as the core, and can also be adjusted by the type and amount of the coupling treatment agent. Aluminium Oxide manufactured by Nippon Aerosil Co., Ltd. is used as the core alumina fine particles.
C etc. are on the market. As the coupling treatment agent, dimethyl silicone, methyltrimethoxysilane,
(3-aminopropyl) trimethoxysilane, (3-aminopropyl) triethoxysilane, {3- (2-aminoethoxyamino) propyl} triethoxysilane,
{3- (2-aminoethoxy) propyl} trimethoxy _{silane, C 8 F 17 SO 2 NC} 2 H 5 (CH 2) 3
Examples include Si (CH ₃ O) ₃ .

In the present invention, as a method for measuring the number of CO ₂ gas adsorption of alumina particles and the specific surface area by the BET method, a commercially available high precision automatic gas adsorption device (BELSORP28, manufactured by Nippon Bell Co., Ltd.) is used. In this case, the specific surface area by the BET method uses N ₂ gas which is an inert gas as the adsorption gas. Specifically, the adsorption amount Vm (cc / g) required to form a monomolecular layer on the surface of alumina particles was measured, and the specific surface area S
(M ² / g) can be obtained. S = 4.35 The ^{× Vm (m 2 / g)} , CO 2 gas adsorption number measures the amount of adsorbed CO ₂ gas can be determined by the following equation.

When alumina particles having a CO ₂ gas adsorption number of more than 4.0 / nm ² are adhered to the surfaces of the toner particles, ambient conditions of normal temperature and normal humidity (25 ° C./60% RH)
Also, under low temperature and low humidity environmental conditions (10 ° C./20% RH), the triboelectric charge amount becomes high during stirring in the developing machine, resulting in a decrease in image density. In addition, high temperature and high humidity environmental conditions (35
At (.degree. C./85% RH), the amount of triboelectricity decreases due to the adsorption of water, causing problems such as increased fog and toner scattering.

When alumina particles having a specific surface area according to the BET method of less than 80 m ² / g are attached to the surface of the toner particles, the ability of the alumina particles as a fluidizing agent is small, so that the positively chargeable color toner easily aggregates. Become. Also,
If the amount of adhesion is less than 0.01% by weight with respect to the toner particles, the effect of adhering alumina particles, that is, the effect of imparting good fluidity and positive chargeability to the color toner cannot be obtained. When more alumina particles are attached to the toner particles, the triboelectric charge amount of the positively chargeable color toner is reduced due to the nature of the alumina particles, which tend to be negatively charged, which increases fog and toner scattering. The problem occurs.

The toner particles according to the present invention are mainly composed of a binder resin, a color colorant and a quaternary ammonium salt, and if necessary, other additives are optionally mixed and melt-kneaded, followed by cooling, solidification and pulverization. Obtained by classifying.

Examples of the binder resin include styrene resin, acrylic acid ester resin, styrene-acrylic acid ester copolymer resin, vinyl chloride resin, vinyl acetate resin, vinylidene chloride resin, phenol resin, epoxy resin, polyester resin and the like. can give.

Examples of color colorants include monoazo red pigments, disazo yellow pigments, quinacridone magenta pigments and phthalocyanine blue pigments. The amount used is 2 to 15 with respect to 100 parts by weight of the binder resin.
Parts by weight are preferred.

Furthermore, the toner particles in the present invention contain a quaternary ammonium salt which gives the toner particles good positive chargeability, and are marketed as quaternary ammonium salts. Product name Bontron P-51 manufactured by Orient Chemical Industry Co., Ltd. and product name Bontron AFP
B, trade name TP-302 and trade name TP-415 manufactured by Hodogaya Chemical Industry Co., Ltd. are listed.

If necessary, low molecular weight polypropylene or low molecular weight polyethylene may be added as an offset preventing agent.

As means for adhering the alumina particles to the surface of the toner particles in the present invention, a general stirrer such as a paddle type stirrer, a turbine type stirrer and a Henschel mixer can be mentioned.

Other surface modifying machines such as Ong Mill manufactured by Honkawa Micron Co., Ltd. and a hybridizer manufactured by Nara Machinery Co., Ltd. can also be used.

When developing with the positively chargeable color toner of the present invention, it is used as a two-component developer by mixing with an iron powder carrier, a ferrite carrier or the like. In this case, a silicone-coated ferrite carrier is preferable in order to maintain the life of the developer for a long time, and a carrier current value of the silicone-coated ferrite carrier is preferably 0.2 to 2.0 μA in order to obtain a high image quality. It may also be used as a non-magnetic one-component developer which does not use a carrier.

[0022]

EXAMPLES Examples of toner blends according to the examples of the present invention and toner characteristic evaluations based thereon will be described below. First,
The following three types of toner particles were prepared. <Toner particles 1> The above raw materials were mixed with a super mixer, melt-kneaded with an extruder, cooled and solidified, then pulverized with a jet mill, and classified to prepare toner particles 1 having an average particle diameter of 14 μm.

<Toner particles 2> Toner particles 2 were prepared from the above raw materials by the same manufacturing method as that for the toner particles 1.

<Toner particles 3> Toner particles 3 were prepared from the above raw materials by the same manufacturing method as that for the toner particles 1.

Next, the toner particles 1 to 3 were used to prepare the following color toners. Example 1 For the toner particles 1, dimethyl silicone 1.2
5% by weight and C ₈ F ₁₇ SO ₂ NC ₂ H ₅ (CH ₂ ) ₃
The number of CO ₂ gas adsorbed on the surface treated with a coupling agent of Si (CH ₃ O) ₃ 2.5 wt% is 3.3 / nm
² , 0.1% by weight of alumina particles having a specific surface area of 87 m ² / g according to the BET method was added, and the mixture was stirred for 1 minute at a rotation speed of 3000 rpm by a Henschel mixer with a capacity of 10 liters to adhere the alumina particles to the surface of the toner particles. Then, a positively chargeable color toner of the present invention colored red was prepared.

Example 2 For the toner particles 2, dimethyl silicone 1.2
5% by weight and C ₈ F ₁₇ SO ₂ NC ₂ H ₅ (CH ₂ ) ₃
The number of CO ₂ gas adsorbed on the surface treated with a coupling agent of Si (CH ₃ O) ₃ 2.5 wt% is 3.3 / nm
² , 0.1% by weight of alumina particles having a specific surface area of 87 m ² / g according to the BET method was added, and the mixture was stirred for 1 minute at a rotation speed of 3000 rpm by a Henschel mixer with a capacity of 10 liters to adhere the alumina particles to the surface of the toner particles. Then, a positively chargeable color toner of the present invention colored yellow was prepared.

Example 3 For the toner particles 3, dimethyl silicone 1.2 was used.
5% by weight and C ₈ F ₁₇ SO ₂ NC ₂ H ₅ (CH ₂ ) ₃
The number of CO ₂ gas adsorbed on the surface treated with a coupling agent of Si (CH ₃ O) ₃ 2.5 wt% is 3.3 / nm
² , 0.1% by weight of alumina particles having a specific surface area of 87 m ² / g according to the BET method was added, and the mixture was stirred for 1 minute at a rotation speed of 3000 rpm by a Henschel mixer with a capacity of 10 liters to adhere the alumina particles to the surface of the toner particles. Then, a positively chargeable color toner of the present invention colored in blue was prepared.

Comparative Example 1 Colloidal silica R-97 was used with respect to the toner particles 1.
2 (manufactured by Nippon Aerosil Co., Ltd.) was added at 0.2% by weight, and 10
Rotation speed 30 by liter capacity Henschel mixer
By stirring at 00 rpm for 1 minute, colloidal silica was adhered to the surface of the toner particles to prepare a color toner for comparison.

Comparative Example 2 The toner particles 1 had a CO ₂ gas adsorption number of 5.
Specific surface area by BET method at 1 piece / nm ² is 92 m ² / g
0.2% by weight of alumina particles was added, and the rotation speed was 3000 rpm by a Henschel mixer with a capacity of 10 liters.
By stirring for 1 minute at m, alumina particles were adhered to the surface of the toner particles to prepare a color toner for comparison.

Comparative Example 3 The toner particles 1 had a CO ₂ gas adsorption number of 4.
Specific surface area by BET method of 4 / nm ² is 10 m ² / g
0.2% by weight of alumina particles was added, and the rotation speed was 3000 rpm by a Henschel mixer with a capacity of 10 liters.
By stirring for 1 minute at m, alumina particles were adhered to the surface of the toner particles to prepare a color toner for comparison.

Comparative Example 4 Colloidal silica R-97 was used with respect to the toner particles 2.
2 (manufactured by Nippon Aerosil Co., Ltd.) was added at 0.2% by weight, and 10
Rotation speed 3 by Henschel mixer of liter capacity
By stirring at 000 rpm for 1 minute, colloidal silica was adhered to the surface of the toner particles to prepare a color toner for comparison.

Comparative Example 5 The toner particles 2 had a CO ₂ gas adsorption number of 5.
Specific surface area by BET method at 1 piece / nm ² is 92 m ² / g
0.2% by weight of alumina particles was added, and the rotation speed was 3000 rpm by a Henschel mixer with a capacity of 10 liters.
By stirring for 1 minute at m, alumina particles were adhered to the surface of the toner particles to prepare a color toner for comparison.

Comparative Example 6 The number of CO ₂ gas adsorbed on the toner particles 2 was 4.
Specific surface area by BET method of 4 / nm ² is 10 m ² / g
0.2% by weight of alumina particles was added, and the rotation speed was 3000 rpm by a Henschel mixer with a capacity of 10 liters.
By stirring for 1 minute at m, alumina particles were adhered to the surface of the toner particles to prepare a color toner for comparison.

Comparative Example 7 Colloidal silica R-97 was used with respect to the toner particles 3.
2 (manufactured by Nippon Aerosil Co., Ltd.) was added in an amount of 0.2% by weight, and 10 was added.
Rotation speed 3 by Henschel mixer of liter capacity
By stirring at 000 rpm for 1 minute, colloidal silica was adhered to the surface of the toner particles to prepare a color toner for comparison.

Comparative Example 8 The toner particles 3 had a CO ₂ gas adsorption number of 5.
Specific surface area by BET method at 1 piece / nm ² is 92 m ² / g
0.2% by weight of alumina particles was added, and the rotation speed was 3000 rpm by a Henschel mixer with a capacity of 10 liters.
By stirring for 1 minute at m, alumina particles were adhered to the surface of the toner particles to prepare a color toner for comparison.

Comparative Example 9 The number of CO ₂ gas adsorbed on the toner particles 3 was 4.
Specific surface area by BET method of 4 / nm ² is 10 m ² / g
0.2% by weight of alumina particles was added, and the rotation speed was 3000 rpm by a Henschel mixer with a capacity of 10 liters.
By stirring for 1 minute at m, alumina particles were adhered to the surface of the toner particles to prepare a color toner for comparison.

Next, 6 parts by weight of each color toner of the above-mentioned Examples and Comparative Examples were mixed with 100 parts by weight of a silicon-coated ferrite carrier having a carrier current value of 1.0 μA and a saturation magnetization of 40 emu / g to prepare a two-component developer. It was created. These two-component developers are used under the environmental conditions described below.
A copy test of up to 00 sheets was conducted, and the results are shown in Tables 1, 2 and 3. Environmental conditions Normal temperature and normal humidity (N / N) ……… 25 ℃ / 60% RH Low temperature and low humidity (L / L) ……… 10 ℃ / 20% RH High temperature and high humidity (H / H) ……… 35 ℃ / 85 % RH

The copy test is performed by a copying machine S manufactured by Sanyo Electric Co., Ltd.
It was performed using FT-Z90. The triboelectric charge amount in the table was measured by a blow-off charge amount measuring device manufactured by Toshiba Chemical Co., the image density was measured by a Macbeth reflection densitometer, and the fog was measured by a color difference meter manufactured by Nippon Denshoku Co., Ltd. For the toner scattering, the scattering condition of the toner around the developing machine was visually determined. The evaluation criteria were ∘: no toner scattering, Δ: small amount of toner scattering, ×: large amount of toner scattering. Further, in order to evaluate the fluidity of the color toner, the bulk specific gravity was measured based on JIS K-5101, and the results are shown in Table 4.

[0039]

[Table 1]

[0040]

[Table 2]

[0041]

[Table 3]

[0042]

[Table 4]

As is clear from Table 1, Table 2 and Table 3, in the examples according to the present invention, the image density was not a practical problem, fogging was small, and toner scattering did not occur. In contrast, in all comparative examples, 50
Toner scattering occurred after 00 sheets, and it was confirmed that fog increased under high temperature and high humidity and low temperature and low humidity environments. Further, from Table 4, it was confirmed that, in the range of Examples and Comparative Examples using the same colorant, the Examples had relatively large bulk specific gravity and excellent fluidity.

[0044]

According to the present invention, the number of CO ₂ gas adsorption is 4.0 or less / nm ² , and the specific surface area by the BET method is 80.
By attaching alumina particles having a characteristic of m ² / g or more to the surface of the toner particles in an amount of 0.01 to 1.0% by weight, excellent positive chargeability can be obtained, sufficient image density can be obtained, and toner scattering and fog can be reduced. Further, it is possible to obtain a positively chargeable color toner for developing an electrostatic charge image, the characteristics of which are not influenced by the surrounding environment.

Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location G03G 9/08 361 (56) Reference JP-A-58-185405 (JP, A) JP-A-62-129860 ( JP, A) JP 62-21169 (JP, A) JP 1-200270 (JP, A)

Claims (3)

[Claims] 1. A surface area of toner particles containing a binder resin, a color colorant and a quaternary ammonium salt as a main component has a CO ₂ gas adsorption number of 4.0 particles / nm ² or less and a specific surface area by a BET method. A positively chargeable color toner comprising alumina particles treated with a coupling treatment agent of 80 m ² / g or more in an amount of 0.01 to 1.0% by weight based on the toner particles. 2. One or two color colorants selected from monoazo red pigments, disazo yellow pigments, quinacridone magenta pigments and phthalocyanine blue pigments.
The positively chargeable color toner according to claim 1, wherein the positively chargeable color toner is at least one kind. 3. The coupling agent is dimethyl silicone, methyltrimethoxysilane, (3-aminopropyl) trimethoxysilane, (3-aminopropyl) triethoxysilane, {3- (2-aminoethoxyamino).
Propyl} triethoxysilane, {3- (2-aminoethoxyamino) propyl} trimethoxysilane and C
₈ F ₁₇ SO ₂ NC ₂ H ₅ (CH ₂ ) ₃ Si (CH ₃ O)
The positively chargeable color toner according to claim 1, wherein the positively chargeable color toner is one or two or more selected from ₃ .