JPH087457B2 - Positively chargeable magenta toner - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a positively chargeable magenta 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 electrostatic charge development. However, since the nigrosine dye is black brown, it is used for black toner, but it cannot be used for full-color toner using yellow, cyan, magenta or the like.
Colorless positive charge control agents used for full-color toners include quaternary ammonium salts and polyamine resins, but all have poor dispersibility in binder resins and are inferior in chargeability to nigrosine dyes. .

A thermoplastic polyester resin is known as a binder resin used for full-color toners, and although it is excellent in light transmission and color superimposing property, its chargeability depends on the acid value contained in the resin. It is easily affected by the hydroxyl value and the like, and it is difficult to control the chargeability only with a positive charge control agent such as a quaternary ammonium salt or a polyamine resin.

Further, the toner is required to have fluidity due to its nature, 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. Colloidal silica has been conventionally used as a fluidizing agent for such toner. However, since the colloidal silica inherently possesses a strong negative chargeability, the toner using the colloidal silica has a positive chargeability which is originally given to the toner while being mixed and stirred with the carrier in the developing device. Are deteriorated, fogging during development, toner scattering, and accumulation of these fluidizing agents in the developer tend to cause problems such as shortening the life of the developer.

In particular, when a quaternary ammonium salt or polyamine resin is contained as a charge control agent, when a thermoplastic polyester resin is used as a binder resin, or when a rhodamine dye is used as a color pigment, or When these materials are used in combination, the chargeability of the toner is easily affected by the chargeability of the colloidal silica, and the decrease in the charge amount is more remarkable than when the nigrosine dye is used as the charge control agent. Fogging during development and toner scattering easily occur.

Further, when a toner having colloidal silica adhered to its surface is developed under high temperature and high humidity, there is a problem that toner is scattered and fog is increased due to a decrease in charge amount due to moisture absorption of colloidal silica. Under low temperature and low humidity, there are problems that the image density decreases and filming occurs with the increase of charging. The present invention solves the above problems caused by the addition of a fluidizing agent,
An object of the present invention is to provide a positively chargeable magenta toner capable of producing a large number of copies without being affected by environmental characteristics, and having no problem of reduction in image density, increase in background fog, poor gradation, toner scattering. To do.

[0007]

SUMMARY OF THE INVENTION The present invention has been made as a result of intensive studies in view of the above-mentioned circumstances, and contains a polyester resin, a xanthene-based rhodamine dye or a lake pigment thereof and a quaternary ammonium salt as main components. The number of CO ₂ gas adsorbed on the surface of the toner particles is 4.0 / nm ²
Alumina particles treated with a coupling treatment agent having the following specific surface area of 80 m ² / g or more by the BET method are
The present invention relates to a positively chargeable magenta toner characterized in that the toner is deposited in an amount of 0.01 to 2.0% by weight with respect to the toner particles.

The alumina particles used in the present invention are ultrafine particles of alumina produced by hydrolyzing anhydrous aluminum chloride at high temperature (flame), and the surface thereof is treated with a coupling treatment agent. _The number of adsorbed ₂ gases 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, a method for measuring the number of CO ₂ gas adsorption of alumina particles and the specific surface area by the BET method is a commercially available high-precision automatic gas adsorption device (BELSORP28, manufactured by Nippon Bell Co., Ltd.) or the like. 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 monolayer on the surface of alumina particles was measured, and the specific surface area S
(M ² / g) can be obtained. S = 4.35 × Vm (m ² / g) The CO ₂ gas adsorption number can be determined by the following formula by measuring the CO ₂ gas adsorption amount.

When alumina particles having a CO ₂ gas adsorption number of more than 4.0 / nm ² are adhered to the surface of the toner particles, environmental conditions of normal temperature and normal humidity (25 ° C./60% RH) and low temperature and low humidity are used. Under the 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 ° 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 based on 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 adhere to the toner particles, the amount of triboelectric charge of the positively chargeable color toner decreases due to the effect of the alumina particles, which tend to be negatively charged, which causes fog increase and toner scattering problems. Occurs.

The toner particles constituting the present invention have a polyester resin, a xanthene-based rhodamine dye or a lake pigment thereof and a quaternary ammonium salt as a main component, and if necessary, other additives are added and melt-kneaded. It is obtained by pulverizing and classifying after cooling and solidifying.

The polyester resin used in the present invention is a polycondensate composed of a polyhydric alcohol and a polybasic acid. Preferred polyhydric alcohol components include, for example, ethylene glycol, glycerin, 1,2-propylene glycol, 1,
3-propylene glycol, neopentyl glycol,
1,4-butanediol, 1,6-hexanediol,
1,4-cyclohexanedimethanol, trimethylolethane, trimethylolpropane, pentaerythritol, etc. are used, and examples of the polybasic acid component include maleic acid, fumaric acid, isophthalic acid, terephthalic acid, adipic acid, sebacic acid. , Trimellitic acid, pyromellitic acetic acid and the like can be used. In addition, a styrene resin, an acrylic ester resin, a styrene-acrylic ester copolymer resin, if necessary for the polyester resin,
Vinyl chloride resin, vinyl acetate resin, vinylidene chloride resin, phenol resin, thermoplastic epoxy resin, polypropylene resin, polyethylene resin and the like can be mixed and used.

The xanthene rhodamine dye or its lake pigment used in the present invention is polyester resin 1
It is preferable to add 2 to 15 parts by weight to 100 parts by weight. When the addition amount is less than 2 parts by weight, the magenta color-developing property is high, and when it is more than 15 parts by weight, the negative charging property becomes strong and the triboelectric charging property tends to be unstable. As a typical example of a xanthene-based rhodamine paint, the following general formula,

Embedded image Compounds of Specific examples of these xanthene-based rhodamine paints include CI Solvent Red 4
9, CI Solvent Red 52, CI Solvent Red 180, etc., and as products, Rhodamine Base 2B, Rhodamine Base FB, Helio Oil Red R,
There are Macrolex Red 5B, Oil Pink OP, Oil Pink 312, etc.

In the toner particles of the present invention, pigments obtained by lake-forming these xanthene-based rhodamine dyes can be used in the same manner as the xanthene-based rhodamine dyes. For example, the following general formula:

Embedded image Rake compound is used. Lake formation of these xanthene-based rhodamine dyes is carried out by a known method.
For example, a dye is dissolved in an acetic acid aqueous solution, and a disodium phosphate aqueous solution, a sodium tungstate aqueous solution, and a sodium molybdate aqueous solution are added to the solution to precipitate a laked pigment. The lake pigment is filtered, washed with water, dried and crushed. Examples of A ⁻ (anion) include not only the above-mentioned phosphates, molybdates, and tungstates, but also sulfates, perchlorates, tetraphenylborate, benzenesulfonate, p-toluenesulfonate, and the like. . If necessary, a xanthene-based rhodamine dye may be mixed with a monoazo-based red pigment, a quinacridone-based magenta pigment, or the like.

The toner particles referred to in the present invention contain a quaternary ammonium salt which imparts a good positive charging property to the toner particles. Orient Chemical Industry Co., Ltd. is marketed as a quaternary ammonium salt. Bontron P-51 and trade name Bontron AFPB, trade name TP-302 and trade name TP-415 from Hodogaya Chemical Co., Ltd.
An example is Bayer's trade name VP SN 4001. In addition, low molecular weight polypropylene or low molecular weight polyethylene may be added as an offset preventing agent, if necessary.

As the 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. In addition, a surface modifier such as an Ong Mill manufactured by Honkawa Micron Co., Ltd. or a hybridizer manufactured by Nara Machinery Co., Ltd. can be applied.

When the positively chargeable magenta toner of the present invention is used for development, it is used as a two-component developer by mixing with an iron powder carrier or a ferrite carrier. 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.

[0019]

EXAMPLES The following is a description of compounding examples of the toner of the examples of the present invention and toner characteristic evaluation based thereon. <Example 1> The above materials were mixed by a super mixer, melt-kneaded by an extruder, cooled and solidified, and then pulverized and classified by a jet mill and an air classifier to produce toner particles having an average particle diameter of 8.5 μm. Then, for the above toner particles, 1.25% by weight of dimethyl silicone and C ₈ F ₁₇ SO ₂ N
C ₂ H ₅ (CH ₂ ) ₃ Si (CH ₃ O) ₃ 2.5 wt%
CO ₂ gas surface-treated with the coupling treatment agent of 3.3 is 3.3 / nm ² , and the specific surface area by BET method is 87.
0.4 wt% of m ² / g of alumina particles was added, and the rotation speed was 30 with a Henschel mixer with a capacity of 10 liters.
The toner particles were stirred at 00 rpm for 1 minute to adhere alumina particles to the surface of the toner particles to prepare a positively chargeable magenta toner of the present invention.

<Example 2> The above materials were mixed by a super mixer, melt-kneaded by an extruder, cooled and solidified, and then pulverized and classified by a jet mill and an air classifier to produce toner particles having an average particle diameter of 8.5 μm. Then, for the above toner particles, 1.25% by weight of dimethyl silicone and C ₈ F ₁₇ SO ₂ N
C ₂ H ₅ (CH ₂ ) ₃ Si (CH ₃ O) ₃ 2.5 wt%
CO ₂ gas surface-treated with the coupling treatment agent of 3.3 is 3.3 / nm ² , and the specific surface area by BET method is 87.
0.2% by weight of m ² / g of alumina particles was added, and the rotation speed was 30 with a Henschel mixer with a capacity of 10 liters.
The toner particles were stirred at 00 rpm for 1 minute to adhere alumina particles to the surface of the toner particles to prepare a positively chargeable magenta toner of the present invention.

<Example 3> The above materials were mixed by a super mixer, melt-kneaded by an extruder, cooled and solidified, and then pulverized and classified by a jet mill and an air classifier to produce toner particles having an average particle diameter of 8.5 μm. Then, for the above toner particles, 1.25% by weight of dimethyl silicone and C ₈ F ₁₇ SO ₂ N
C ₂ H ₅ (CH ₂ ) ₃ Si (CH ₃ O) ₃ 2.5 wt%
CO ₂ gas surface-treated with the coupling treatment agent of 3.3 is 3.3 / nm ² , and the specific surface area by BET method is 87.
0.1 wt% of m ² / g of alumina particles was added, and the rotation speed was 30 with a Henschel mixer with a capacity of 10 liters.
The toner particles were stirred at 00 rpm for 1 minute to adhere alumina particles to the surface of the toner particles to prepare a positively chargeable magenta toner of the present invention.

Comparative Example 1 To the toner particles of Example 1, 0.1% by weight of colloidal silica R-972 (manufactured by Nippon Aerosil Co., Ltd.) was added, and a 1-liter Henschel mixer was operated at 1 rpm at 3000 rpm. After stirring for a minute, colloidal silica was adhered to the surface of the toner particles to prepare a magenta toner for comparison.

Comparative Example 2 To the toner particles of Example 1, 0.2 weight of alumina particles having a CO ₂ gas adsorption number of 5.1 / nm ² and a BET specific surface area of 92 m ² / g was used. %, And was stirred for 1 minute at a rotation speed of 3000 rpm by a Henschel mixer having a capacity of 10 liters to prepare a magenta toner for comparison in which alumina particles were adhered to the surfaces of the toner particles.

Comparative Example 3 0.2 weight of alumina particles having a CO ₂ gas adsorption number of 4.4 / nm ² and a BET specific surface area of 10 m ² / g is added to the toner particles of Example 1. %, And was stirred for 1 minute at a rotation speed of 3000 rpm by a Henschel mixer having a capacity of 10 liters to prepare a magenta toner for comparison in which alumina particles were adhered to the surfaces of the toner particles.

<Comparative Example 4> The above materials were mixed by a super mixer, melt-kneaded by an extruder, cooled and solidified, and then pulverized and classified by a jet mill and an air classifier to produce toner particles having an average particle diameter of 8.5 μm. Then, for the above toner particles, 1.25% by weight of dimethyl silicone and C ₈ F ₁₇ SO ₂ N
C ₂ H ₅ (CH ₂ ) ₃ Si (CH ₃ O) ₃ 2.5 wt%
CO ₂ gas surface-treated with the coupling treatment agent of 3.3 is 3.3 / nm ² , and the specific surface area by BET method is 87.
0.4 wt% of m ² / g of alumina particles was added, and the rotation speed was 30 with a Henschel mixer with a capacity of 10 liters.
By stirring at 00 rpm for 1 minute, a magenta toner for comparison in which alumina particles were attached to the surfaces of the toner particles was prepared.

Next, 5 parts by weight of each magenta toner of the above-mentioned examples and comparative examples were mixed with 100 parts by weight of a silicone-coated ferrite carrier having a carrier current value of 1.0 μA and a saturation magnetization of 40 emu / g, and two-component development was carried out. The agent was created. These two-component developers were subjected to a copy test up to 5000 sheets under the environmental conditions described below, and the results are shown in Table 1. Environmental conditions Normal temperature and humidity (N / N) ───── 25 ℃ / 60% RH High temperature and high humidity (H / H) ─────35 ℃ / 85% RH Low temperature and low humidity (L / L) ─── ──10 ℃ / 20% RH

The copying tester was a copying machine SF-8300 manufactured by Sharp Corporation. The triboelectric charge amount in the table was measured by a blow-off charge amount measuring device manufactured by Toshiba Chemical Company, the image density was measured by a reflection densitometer RD-914 manufactured by Macbeth Co., and the fog was measured by a color difference meter TC-60S manufactured by Nippon Denshoku Co., Ltd. The toner scattering was determined by visually observing the toner scattering around the developing device. The evaluation criteria were as follows: ◯: no toner scattering, Δ: small amount of toner scattering, x: large amount of toner scattering. In addition, in order to evaluate the fluidity of the magenta toner,
The bulk specific gravity was measured based on JIS K-5101, and the results are shown in Table 2.

[0028]

[Table 1]

[0029]

[Table 2]

As is apparent from Table 1, in the examples according to the present invention, the image density was practically no problem, the fog was small, and the toner was not scattered. In contrast, in all the comparative examples, toner scattering occurred after 5,000 sheets, and an increase in fog was confirmed under high-temperature, high-humidity, and low-temperature, low-humidity environments. In addition, it was confirmed from Table 2 that the example has a relatively large bulk specific gravity and excellent fluidity.

[0031]

According to the present invention, the number of CO ₂ gas adsorption is 4.0 / nm ² or less, and the specific surface area by the BET method is 80 m.
By attaching alumina particles having a characteristic of ² / g or more to the surface of the toner particles in an amount of 0.01 to 2.0% by weight, excellent positive chargeability can be obtained, sufficient image density can be obtained, toner scattering and fog can be reduced, and It is possible to obtain a positively chargeable magenta toner for developing an electrostatic image which is not affected by the environment having these characteristics.

Continuation of front page (51) Int.Cl. ⁶ Identification number Reference number in the agency FI Technical indication location G03G 9/08 361 (72) Inventor Hideo Fujita No. 3 Soba-cho, Shizuoka-shi, Shizuoka Tomoegawa Paper Co., Ltd. In-house Chemicals Factory Examiner Hiroshi Fukatsu (56) Reference JP-A-58-185405 (JP, A) JP-A-62-129860 (JP, A) JP-A-62-21169 (JP, A) JP-A-Hei 1-200270 (JP, A)

Claims (2)

[Claims] 1. A surface of toner particles containing a polyester resin, a xanthene-based rhodamine dye or a lake pigment thereof and a quaternary ammonium salt as a main component, has a CO ₂ gas adsorption number of 4.0 / nm ² or less, and Alumina particles treated with a coupling treatment agent having a specific surface area by the BET method of 80 m ² / g or more were added to the toner particles in an amount of 0.
A positively chargeable magenta toner characterized by being deposited in an amount of 01 to 2.0% by weight. 2. 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 magenta toner according to claim 1, which is one kind or two or more kinds selected from ₃ .