JP2515576B2 - Negatively chargeable cyan cyan toner and method for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a negatively chargeable polymerized cyan color toner used in a method for developing a latent image and a method for producing the same.

[Prior Art] A large number of electrophotographic methods are known as described in US Pat. No. 2,297,691 and the like. Generally, a photoconductive material is used and various methods are used to form an image on the photoreceptor. Form an electrical latent image on it, and then develop the latent image with toner,
If necessary, the toner image is transferred to a transfer member such as paper and then fixed by heating, pressure, solvent vapor or the like to obtain a copy. As a method of developing with a toner and a method of fixing, various kinds of methods have been conventionally proposed and used as needed. Further, in order to obtain a multicolor image of color, the original is exposed using a color separation filter, and the above steps are repeated a plurality of times using cover toners such as yellow, magenta, and cyan to superimpose the toner images. This is a color image.

Conventionally, as a toner used for these purposes, a colorant has generally been melt-mixed in a thermoplastic resin and uniformly dispersed, and then a toner having a desired particle diameter is manufactured by a fine pulverizer / classifier.

Although this manufacturing method can produce a fairly excellent toner,
There are certain restrictions, namely the selection range of toner materials. For example, the resin colorant dispersion must be sufficiently brittle to be finely pulverized in economically feasible manufacturing equipment. However, if the resin colorant dispersion is made brittle in order to meet these requirements, the particle size range of the particles formed when the particles are actually pulverized at a high speed tends to be wide, and in particular, a relatively large proportion of fine particles is The problem of being included in. Further, such a brittle material is more susceptible to fine pulverization or pulverization when used for developing such as a copying machine. Further, in this method, it is difficult to completely and uniformly disperse solid fine particles such as a colorant in the resin, and depending on the degree of the dispersion, an increase in fog, a decrease in image density, and color mixing / transparency Care must be taken in dispersion, as this can cause defects. In addition, the exposure of the colorant on the fracture surface may cause fluctuations in the developing characteristics.

On the other hand, in order to overcome the problems of the toner due to the pulverization method, Japanese Patent Publications No. 36-10231, No. 43-10799 and No. 51-14895.
A method for producing a toner by a suspension polymerization method is proposed in Japanese Patent Publication No. In the suspension polymerization method, a polymerizable monomer,
A colorant, a polymerization initiator and, if necessary, a cross-linking agent, a charge control agent, and other additives are uniformly dissolved or dispersed to form a monomer composition, and the monomer composition contains a dispersion stabilizer. Are dispersed in a continuous phase, for example, an aqueous phase, using a suitable stirrer, and a polymerization reaction is performed at the same time to obtain toner particles having a desired particle size.

Since this method does not include all crushing steps, the toner does not need to be brittle and a soft material can be used.
Further, there is an advantage that a colorant is not exposed on the surface of the particles and uniform triboelectricity is obtained.

As blue-based colorants used in conventional toner,
Copper phthalocyanine described in JP-B-54-1464 and colorants other than phthalocyanine-based compounds described in JP-B-57-3940, JP-B-55-10907, JP-B-58-9415, etc. It has been known. Among these colorants, phthalocyanine-based pigments are excellent in terms of their tinting strength, light resistance, price, etc., but their dispersibility in toner particles is not sufficient, and particularly images are formed on a transparent carrier. The toner becomes inferior in light transmissivity when pressed.

In the cyan toner obtained by the actual pulverization method, even if a kneader having a high shearing force such as a triple roll is used, the colorant is not sufficiently dispersed, and therefore the transparency of the image on the transparent support after fixing is not improved. It is damaged.

[Problems to be Solved by the Invention] As described above, there is a strong demand for a cyan toner having good spectral reflection characteristics, color mixing properties, transparency, and developability.

[Means and Actions for Solving Problems] That is, the present invention provides a polymerizable monomer containing at least a polymerizable monomer, β-type copper phthalocyanine blue, a metal complex salt of salicylic acid or dialkylsalicylic acid, and an anionic polymer. The present invention relates to a negatively chargeable polymerized cyan color toner having negatively chargeable polymerized cyan color toner particles obtained by suspension polymerization of a body composition in an aqueous medium.

Further, the present invention is a suspension polymerization of a polymerizable monomer composition containing at least a polymerizable monomer, β-type copper phthalocyanine blue, a metal complex salt of salicylic acid or dialkyl salicylic acid, and an aniline polymer in an aqueous medium. The present invention relates to a method for producing a negatively chargeable polymerized cyan color toner, which comprises producing negatively charged polymerized cyan color toner particles.

 Hereinafter, the present invention will be described in detail.

As a result of diligent studies, the present inventors have paid attention to the fact that copper phthalocyanine blue is a cationic substance, and contribute to the improvement of pigment dispersibility by allowing an anionic polymer to coexist in the monomer composition. The present invention has been completed and the present invention has been achieved.

Generally, in a suspension polymerization method, a substantially incompatible polymerizable monomer composition is dispersed in a dispersion medium represented by water and polymerized to form toner particles. Due to this characteristic of the production method, a water-soluble material, a material having a polymerization inhibitory property, a material lacking stability in a polymerizable monomer composition, etc. cannot be used. From these viewpoints and the hue of the obtained toner particles, the present inventors have studied copper phthalocyanine pigments, and as a result, only β-type copper phthalocyanine blue has dispersibility and coexistence in the presence of an anionic polymer. It was found that the obtained toner particles can be used in terms of hue. The β-type copper phthalocyanine blue is used in an amount of 1 to 15 parts by weight, preferably 2 to 10 parts by weight, based on 100 parts by weight of the polymerizable monomer. If the addition amount is less than 1 part by weight, the coloring power is not sufficient, and if the addition amount is more than 15 parts by weight, the coloring power is not improved.

Further, as the anionic polymer used in the present invention,
In addition to cyclized rubbers, polymers of unsaturated carboxylic acids / unsaturated dibasic acids such as acrylic acid, anhydrides of unsaturated dibasic acids, copolymers of these with styrene, and cyclized rubbers can be mentioned.
Further, a metal complex salt of salicylic acid or dialkyl salicylic acid, which is an anionic substance, is used in combination with the anionic polymer. The anionic polymer and the metal complex salt are used in an amount of 0.5 to 20 parts by weight, preferably 1 to 10 parts by weight, based on 100 parts by weight of the polymerizable monomer. If the addition amount of the anionic polymer and the metal complex salt is less than 0.1 parts by weight, sufficient dispersion of the colorant cannot be obtained, and if it is more than 15 parts by weight, it affects the granulability of the toner particles, and The particles have a wide distribution.

When polymerizing the polymerizable monomer composition containing the anionic polymer and the metal complex salt, it is preferable to suspend and polymerize in a water phase in which a cationic dispersant is dispersed.

That is, the anionic polymer and the metal complex salt contained in the polymerizable monomer composition are the cationic dispersant of opposite charge type dispersed in the aqueous phase and the electrostatic charge on the surface of the particles which will be the toner during the polymerization. And the dispersant covers the surfaces of the particles to prevent coalescence between the particles and stabilize the particles. On the other hand, the cationic β-type copper phthalocyanine blue cannot exist in the surface layer due to electrostatic repulsion with the cationic dispersant,
It does not affect the triboelectric chargeability of the toner particles.

As the polymerizable monomer used in the present invention, styrene, o-
Styrene and its derivatives such as methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-ethylstyrene; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate. , N-octyl methacrylate, dodecyl methacrylate, 2-ethylenehexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and other methacrylate esters; methyl acrylate, acrylic acid Ethyl, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate,
There are acrylic acid esters such as 2-chloroethyl acrylate and phenyl acrylate; vinyl-based monomers such as acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile and acrylamide.

These monomers may be used alone or as a mixture. Among the above-mentioned monomers, styrene or a styrene derivative may be used alone or as a mixture with other monomers,
It is preferable in terms of developing characteristics and durability of the toner.

Alternatively, it is preferable to polymerize the monomer by adding a polymer or copolymer having a polar group as an additive during the polymerization of the monomer.

Further, for the purpose of improving releasability at the time of heat roll fixing, waxes generally used as a releasing agent such as hydrocarbon compounds and carnauba wax may be blended in the toner.

The hydrocarbon compounds that can be used in the present invention include paraffins and polyolefins having a carbon chain of C ₆ or more. This hydrocarbon compound has a softening point of 50 to 13
It is preferable to use one at 0 ° C. More specifically,
Examples of the hydrocarbon compound include paraffin wax (manufactured by Nippon Oil Co., Ltd.), paraffin wax (manufactured by Nippon Seiro Co., Ltd.), microwax (manufactured by Nippon Oil Co., Ltd.), microcristan wax (manufactured by Nippon Seiro Wax Co., Ltd.), PE-130 (manufactured by Hoechst). ), Mitsui High Wax 110P (Mitsui Petrochemical), Mitsui High Wax 220P (Mitsui Petrochemical), and Mitsui High Wax 660P (Mitsui Petrochemical). Among them, low molecular weight polyethylene, low molecular weight polypropylene and paraffin are particularly preferably used.

As the polymerization initiator, any suitable polymerization initiator, for example, 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′- Azobis (cyclohexane-1-carbonitrile), 2,
2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, other azobisisobutyronitrile (AIBN)
Azo or diazo polymerization initiators such as; benzoyl peroxide, methyl ethyl ketone peroxide, isopropyl peroxycarbonate, cumene hydroperoxide, peroxide polymerization initiators such as 2,4-dichlorylbenzoyl peroxide, lauroyl peroxide Agents. For these polymerization initiators, about 0.5 to 5% by weight of the polymerizable monomer is generally sufficient.

At the time of polymerization, a cross-linking polymer may be formed by allowing the following cross-linking agent to be present.

Examples of such a crosslinking agent include divinylbenzene, divinylnaphthalene, divinyl ether, divinyl sulfone, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, diethylene glycol diacrylate,
Triethylene glycol diacrylate, 1,3-butylene glycol dimethacrylate, 1,6-hexane glycol dimethacrylate, neopentyl glycol dimethacrylate, dipropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, 2,
2'-bis (4-methacryloxydiethoxyphenyl)
Propane, 2,2′-bis (4-acryloxydiethoxyphenyl) propane, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, dibromoneopentyl glycol dimethacrylate, diallyl phthalate, etc., A general crosslinking agent can be used as appropriate.

If the amount of these cross-linking agents used is large, the toner becomes difficult to dissolve, and the fixability becomes poor. When the amount used is small, properties such as blocking resistance and durability required as a toner deteriorate, and in the heat roll fixing, a part of the toner does not completely adhere to the paper and adheres to the roller surface, It becomes difficult to prevent the offset phenomenon of transferring to paper. Therefore, the amount of these crosslinking agents used is preferably 0.001 to 1% by weight, more preferably 0.005 to 0.5% by weight, based on the total amount of the monomers.

Further, a fluidity modifier may be added to the toner, if necessary. The fluidity modifier may be mixed (externally added) with the toner particles and used.

Examples of fluidity modifiers include colloidal silica and fatty acid metal salts. Further, for the purpose of increasing the amount, a filler such as calcium carbonate or fine powder silica may be blended in the toner in the range of 0.5 to 20% by weight. Further, in order to prevent aggregation of the toner particles and improve the fluidity, a fluidity improver such as Teflon fine powder may be added.

 The toner according to the present invention is obtained by the following method.

Colorant, cross-linking agent, other additives such as a polymerization initiator are added to the polymerizable monomer, and the suspension system contains a suspension of a monomer system that is uniformly melted or dispersed by an ultrasonic disperser, a homogenizer, or the like. It is dispersed in a water phase (that is, a continuous phase) by a usual stirrer, a homomixer, a homogenizer or the like. Preferably, the stirring speed and time are adjusted so that the monomer droplets have a desired toner particle size of generally 30 μm or less, and thereafter, the stirring is carried out in order to maintain almost that state by the action of the dispersion stabilizer. Should be performed to the extent that the sedimentation is prevented. Polymerization temperature is 40 ℃ or higher, generally 50-90
Polymerization is carried out by setting the temperature at ℃. After completion of the reaction, the produced toner particles are washed, recovered by filtration, and dried. In the suspension polymerization method, 3 parts of water is usually added to 100 parts by weight of the monomer.
00 to 3000 parts by weight are used as the dispersion medium.

The polymerized toner obtained in the present invention can be applied to a known dry electrostatic image developing method without particular limitation. For example, a two-component developing method such as a cascade method, a magnetic brush method, a microtoning method, and a two-component AC bias developing method; a powder cloud method and a fur brush method; the toner is retained by electrostatic force on the toner carrier. It is applicable to a non-magnetic one-component developing method in which the toner is conveyed to the developing section and is used for development; an electric field curtain developing method in which toner is conveyed to the developing section by the electric field curtain method and is used for development.

As described above, according to the method for producing a polymerized toner of the present invention, a suspension of a polymerizable monomer composition in which β-type copper phthalocyanine blue, an anionic polymer, and a metal complex salt of salicylic acid or dialkylsalicylic acid are allowed to coexist. By carrying out the polymerization, a cyan toner having a clear color tone can be obtained.

[Examples] Hereinafter, the present invention will be described more specifically based on Examples.

 All parts in the following formulations are parts by weight.

Example 1 0.5 g of γ-aminopropyltrimethoxysilane was added to 1200 ml of ion-exchanged water, 10 g of Aerosil 200 (Nippon Aerosil) was further added, and the mixture was heated to 70 ° C., and TK type homomixer M type (made by Tokushu Kika Kogyo Co., Ltd.). ) Was used for 15 minutes at 10,000 rpm. Furthermore, 19 g of N / 10 HCl was added to adjust the system pH to 6.

The components of the above formulation were heated to 70 ° C. in a container and dissolved and dispersed in a TK type homomixer M type at 10,000 rpm for 5 minutes to obtain a monomer mixture. While maintaining the temperature at 70 ° C, 10 parts of an initiator V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) was added and dissolved to prepare a monomer composition.

In a 2 liter flask containing the dispersion medium obtained above, the above monomer composition was charged, and the mixture was stirred at 7000 rpm for 60 minutes using a TK homomixer at 70 ° C. under a nitrogen atmosphere, and the monomer composition was added. The thing was granulated. Then, while stirring with the paddle stirring blade, 70
Polymerization was carried out at 0 ° C for 10 hours. After the completion of the polymerization reaction, the reaction product was cooled, NaOH was added to dissolve the dispersant, and the mixture was washed with water and dried to obtain a negatively charged polymerized cyan color toner.

The particle diameter of the obtained toner was measured with a Coulter counter (aperture diameter: 100 μm), and the volume average diameter was 11.
It had a sharp particle size distribution at 5 μm. The amount of triboelectrification of this toner with respect to iron powder (200/300 mesh) by the blow-off method was -18 μC / g.

After the ner particles were dispersed in an epoxy resin and cured, they were sliced with a microtome to a thickness of 2 μm, and the dispersibility of the pigment was evaluated by using an optical microscope. It turned out to be dispersed.

Example 2 A toner was obtained in the same manner as in Example 1 except that the above formulation was used.

The particle diameter of the obtained toner was measured by a Coulter counter (aperture diameter: 100 μm), and it was found that the volume average diameter was 10.
It had a sharp particle size distribution of 8 μm. The amount of triboelectrification of this toner on iron powder (200/300 mesh) by the blow-off method was -20 μC / g.

When the dispersibility of the pigment was evaluated using this toner in the same manner as in Example 1, the presence of aggregates of the pigment was not recognized.

Example 3 Using the above formulation, a toner was obtained in the same manner as in Example 1, except that the number of granulations was set to 10,000 rpm to carry out polymerization. The particle size of the obtained toner was measured with a Coulter counter (aperture size: 100 μm), and it was found that the volume average size was 5.8 μm and the particle size distribution was sharp. The amount of triboelectrification of this toner on iron powder (200/300 mesh) by the blow-off method was -25 μC / g.

When this toner was evaluated for pigment dispersibility in the same manner as in Example 1, the presence of aggregates of pigment was not recognized.

Example 4 A toner was obtained in the same manner as in Example 1 except that the above formulation was used.

The particle diameter of the obtained toner was measured by a Coulter counter (aperture diameter: 100 μm), and it was found that the volume average diameter was 10.
It had a sharp particle size distribution at 5 μm. The amount of triboelectrification of this toner to iron powder (200/300 mesh) by the blow-off method was -24 μC / g. Using this toner, the dispersibility of the pigment was evaluated in the same manner as in Example 1.
The presence of pigment aggregates was not observed.

Comparative Example 1 Polymerization was carried out in the same manner as in Example 1 except that α-type copper phthalocyanine blue (CI Pigment 15) was used as the colorant.

However, during the granulation process, the agglomeration of the pigment was significant, and there was a large difference in the pigment content among the particles. For this reason, the granulation property was poor, the obtained particles had a wide particle size distribution, and the pigment dispersion was non-uniform, so that they could not be used as toners.

Comparative Example 2 Polymerization was carried out in the same manner as in Example 1 except that CI Pigment Blue 17 which was a chloro substitution product of α-type copper phthalocyanine blue was used as the colorant. The resulting toner was greenish, but its spectral reflection characteristics were insufficient for use as a cyan toner.

 ─────────────────────────────────────────────────── --Continued from the front page (56) Reference JP-A-57-26855 (JP, A) JP-A-61-112158 (JP, A) JP-A-63-73268 (JP, A) JP-A-59- 64850 (JP, A)

Claims (2)

(57) [Claims] 1. A polymerizable monomer composition containing at least a polymerizable monomer, β-type copper phthalocyanine blue, a metal complex salt of salicylic acid or dialkyl salicylic acid, and an anionic polymer is subjected to suspension polymerization in an aqueous medium. A negatively chargeable polymerized cyan color toner comprising the obtained negatively chargeable polymerized cyan color toner particles. 2. A polymerizable monomer composition containing at least a polymerizable monomer, β-type copper phthalocyanine blue, a metal complex salt of salicylic acid or dialkyl salicylic acid, and an anionic polymer is subjected to suspension polymerization in an aqueous medium, A method for producing a negatively charged polymerized cyan color toner, which comprises producing negatively charged polymerized cyan color toner particles.