JP2658006B2 - Electrostatic image developing toner and method of manufacturing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electrostatic image developing toner used for electrophotography and the like, and more particularly, to a toner such as a carrier without contaminating the surface of a triboelectric charging member. The present invention relates to a long-life toner for developing an electrostatic image, which can provide stable frictional charging characteristics.

(Prior art) An electrostatic image developing toner used in the field of electrophotography or the like generally comprises colored resin particles of 5 to 20 μm in which a colorant, a charge controlling dye, and the like are dispersed in a resin medium.
As the resin medium, a resin having a desired electric detecting property and binding property, for example, a styrene-based resin or the like is used.As the coloring agent, carbon black or another organic or inorganic coloring pigment is used. Nigrosine, monoazo dyes, metal complexes of salicylic acid and naphthoic acid and the like are used as control dyes. The most typical production method of the toner for developing an electrostatic image is to melt-knead the above-described resin medium, a colorant and a dye for charge control, cool the kneaded composition, pulverize and classify the mixture to a certain particle size range. This is a so-called crushing method including a process of aligning. However, the yield of the toner obtained by this pulverization / classification is extremely low, and the apparatus itself requires a large amount of equipment, which makes the production cost of the toner extremely high. Furthermore, the toner obtained by this pulverization method has a defect that the fluidity of the toner is generally low due to the irregular shape of the particles, and blocking tends to occur.

Therefore, in order to improve the disadvantages of the irregular toner obtained by the pulverization method, attempts have been made to produce spherical toner particles to improve the fluidity and triboelectric chargeability. The spherical toner is prepared by dissolving or dispersing a binder resin, a colorant, a charge controlling dye, and the like in an organic solvent such as toluene, and spray-drying the resin solution to obtain a toner. A polymerizable composition comprising a monomer, a colorant, a charge controlling dye and the like can be obtained by a suspension polymerization method in which a toner is directly produced by suspending a polymerizable composition in an aqueous dispersion medium to carry out a polymerization reaction. As described above, the spherical toner is superior in fluidity to the irregular toner, and the stirring property and the transport property in the developing device are improved. In addition, the spherical toner has a large contact area with a frictional charging member such as a toner or a magnetic carrier (when used as a two-component developer), so that the friction between the particles is effectively performed and the fluidity is good. In this connection, the triboelectric charging can be performed uniformly and efficiently.

However, the present inventors have repeatedly studied and found the following problems. In other words, the toner spheroidized to a certain level has a large effective area for contact friction on the particle surface, and the toner particles have high motility, so that the toner has excellent triboelectric charging efficiency and good charge start-up characteristics. However, the charge controlling dye present on the particle surface drops off due to sharp friction stirring, contaminating the surface of the triboelectric charging member such as carrier particles, gradually destabilizing the triboelectric characteristic, and continues copying. In this case, image fogging and image density decrease occur.

The present invention has been made in view of the above points, and an object of the present invention is to provide a spherical toner capable of obtaining a stable frictional charging characteristic for a long time without contaminating a frictional charging member such as carrier particles or a stirring member in a developing device. And a method of manufacturing the same.

Another object of the present invention is to provide a toner capable of stably obtaining a clear image with high resolution, high density and no fog for a long period of time, and a method for producing the same.

(Means for Solving the Problems) According to the present invention, in a toner for developing an electrostatic image in which at least a colorant and a charge controlling dye are dispersed in a binder resin, the roundness represented by the following formula is obtained. The present invention provides a toner for electrostatic charge development, which is spherical particles of 0.95 to 1.0 and has a surface dye concentration of 1 × 10 ^{−3 to} 4 × 10 ⁻³ g / g.

Wherein, r _l represent the major axis of the toner particles, r _s represents the minor axis of the toner particles.

In the present invention, it is preferable to adjust the surface dye concentration of the toner by immersing the spherical particles in an organic solvent in which the charge controlling dye is dissolved.

Furthermore, in the present invention, the spherical particles preferably have a volume-based median diameter of 5 to 11 μm, and D ₂₅ / D ₇₅ representing the degree of dispersion of the particle diameter is preferably 1.2 to 1.6.

Furthermore, in the present invention, the spherical particles are preferably polymer particles directly produced by a suspension polymerization method.

Further, according to the present invention, after obtaining spherical particles having a roundness of 0.95 to 1 represented by the following formula in which at least a colorant and a charge controlling dye are dispersed in a binder resin, the charge controlling dye is obtained. Is to disperse the spherical particles in an organic solvent that dissolves or disperses but does not dissolve the resin component, and uniformly attaches the charge control dye to the entire surface of the particle while washing off unnecessary portions of the charge control dye existing on the particle surface. And a method for producing a toner for electrostatically developed images.

Wherein, r _l represent the major axis of the toner particles, r _s represents the minor axis of the toner particles.

In the present invention, the final dye concentration on the particle surface is 1
It is preferably adjusted to × 10 ^-3 to 4 × 10 ^-3 g / g.

Further, in the present invention, the spherical particles having the roundness include a polymerizable composition comprising at least a polymerizable monomer, a colorant, and 0.1% by weight or more of a charge controlling dye based on the polymerizable monomer. The volume-based median diameter obtained by performing a polymerization reaction after suspending the product in an aqueous phase is in the range of 5 to 11 μm, and D ₂₅ / D ₇₅ representing the degree of dispersion of the particle size is in the range of 1.2 to 1.6. Preferably, the polymer particles are certain.

(Function) The present invention is characterized in that the toner particles are made substantially spherical and the dye concentration on the surface of the toner particles is adjusted to a specific range.

The charge control dye is originally used to actively generate the charge of the toner, improve the saturation charge amount, and satisfactorily improve the charge rising characteristics. For this reason, the charge controlling dye is preferably present on the particle surface of the toner in the frictional charging with the frictional charging member, but most of the charge controlling dyes are hydrophilic and are not necessarily excellent in compatibility with the binder resin. When the concentration of the dye present on the surface is higher than a certain concentration, the amount of dye that cannot be sufficiently fixed on the particle surface increases. In some cases, the dye may come off by contact. This is more remarkable in spherical toner particles having excellent stirring and friction efficiency.

In the present invention, the roundness represented by the above equation (1) is 0.95.
The surface dye concentration of a substantially spherical toner of about 1.0 to 4 × 10 ^-3 g / g
In addition, since the dye is uniformly attached in a thin layer state on the particle surface, the amount of the dye that drops off during friction stirring is reduced. That is, the frequency of contact with the triboelectric charging member is increased by the agitation and fluidity of the substantially spherical particles, and stable triboelectric charging characteristics are obtained with the minimum necessary dye concentration. At this time, if the dye concentration is too low, the desired charge amount cannot be obtained from the beginning, and 1 × 10 ^-3
If it is less than g / g, a good image cannot be formed. Also, even if it has a dye concentration within the above range, the roundness of the particles is 0.
If it is less than 95, the frequency of contact friction decreases, and it becomes impossible to increase the toner charge amount to an appropriate range, so that good development cannot be performed.

In the present invention, the production method is not particularly limited as long as particles having a surface dye concentration in the above-mentioned concentration range and a roundness of 0.95 to 1 can be obtained. After forming the spherical toner, the surface dye concentration can be adjusted to the above range. In this case, the charge controlling dye is dissolved or dispersed but the resin component is not dissolved in an organic solvent in which the spherical toner particles having a surface dye concentration larger than the above-described range are immersed, and the excess surface dye is removed. A method of washing off is used. According to this method, unnecessary dyes can be washed off at the same time and a required amount of dyes can be uniformly and uniformly fixed on the particle surface, and the life can be further extended. Further, when the spherical toner of the present invention is obtained by a suspension polymerization method, oil droplet particles are suspended and dispersed in an aqueous phase and polymerized, and a charge controlling dye is unevenly distributed on the surface of the oil droplet particles during the polymerization step. Since the immersion treatment in an organic solvent described above can remove the residual monomer component in the toner particles simultaneously with fixing the dye, the humidity resistance and durability of the toner can also be improved.

Incidentally, the surface dye concentration referred to in the present specification was precisely weighed 100 mg of toner, added 50 ml of methanol, stirred for 10 minutes with a ball mill, and allowed to stand for 1 day. Then, the supernatant liquid concentration was measured by an absorptiometer. The density is calculated by the Lambert-Beer law.

(Preferred Aspects of the Invention) Various compounding materials in the case of directly manufacturing a toner by a suspension polymerization method will be described below. As the polymerizable monomer constituting the binder resin by polymerization, various addition polymerization type monomers are used.

Suitable examples of such a monomer include a vinyl aromatic monomer, an acrylic monomer, a vinyl ester monomer, a vinyl ether monomer, a diolefin monomer, and a monoolefin monomer. And so on. As the vinyl aromatic monomer, the formula, In the formula, R ₁ is a hydrogen atom, a lower alkyl group or a halogen atom, and R ₂ is a hydrogen atom, a lower alkyl group, a halogen atom, an alkoxy group, a nitro group, or a vinyl group. For example, styrene, α-methylstyrene, vinyltoluene, α-chlorostyrene, o
-, M-, p-chlorostyrene, p-ethylstyrene,
Divinylbenzene can be used alone or in combination of two or more. Further, the other monomers described above include the following.

formula, In the formula, R ₃ is a hydrogen atom or a lower alkyl group R ₄ is a hydrogen atom, a hydrocarbon group having up to 12 carbon atoms, a hydroxylalkyl group, or a vinyl ester group, an acrylic monomer such as methyl acrylate, Ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, hexyl methacrylate,
2-ethylhexyl methacrylate, ethyl β-hydroxyacrylate, propyl γ-hydroxyacrylate,
σ-butyl acrylate, β-hydroxyethyl methacrylate, ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, and the like.

formula, Wherein R ₅ is a hydrogen atom or a lower alkyl group, such as vinyl esters such as vinyl formate, vinyl acetate and vinyl propionate.

formula, In the formula, R ₆ is a monovalent hydrocarbon group having up to 12 carbon atoms, for example, vinyl ethers such as vinyl-n-butyl ether, vinyl phenyl ether, and vinyl cyclohexyl ether.

formula, Wherein each of R ₇ , R ₈ , and R ₉ is a hydrogen atom, a lower alkyl group, or a halogen atom, especially dienes, butadiene, isoprene, and chloroprene.

formula, Wherein each of R ₁₀ and R ₁₁ is a hydrogen atom or a lower alkyl group, such as ethylene, propylene, isobutylene, butene-1, butene-1, pentene-1, 4-methylpentene-1 and the like.

I will give you a list.

One or more of these monomers can be used, but from the viewpoint of fixability, the main component of the monomer should be at least one selected from the group consisting of styrene, acrylate and methacrylate. Is preferred.

Further, in order to further stabilize the charging characteristics of the toner, a monomer having a polar group for charge control can be used. Examples of those having an anionic group include maleic anhydride, crotonic acid, tetrahydromaleic anhydride, styrenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, and the like. Is dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, N
-Aminoethylaminopropyl (meth) acrylate,
Vinyl pyridine, 2-vinyl imidazole, 2-hydroxy-3-acryloxypropyl, trimethylammonium chloride and the like can be mentioned. When these anionic or cationic group-containing monomers are used, they may be contained in an amount of about 0.01 to 10% by weight based on the above polymerizable monomers.

As the colorant to be contained in the above-mentioned polymerizable monomer, known pigments and dyes (hereinafter simply referred to as color pigments) used in this field as exemplified below can be used.

Black pigments Carbon black, acetylene black, lamp black, aniline black.

Yellow pigment Yellow lead, zinc yellow, cadmium yellow, yellow iron oxide, mineral first yellow, nickel titanium yellow,
Navels Yellow, Teftor Yellow S, Hansa Yellow 10G, Benzidine Yellow G, Quinoline Yellow Lake, Permanen Yellow NGG, Tartrazine Lake.

Orange pigments Red mouth lead, molybdenum orange, permanent orange GTR, pyrazolone orange, Vulcan orange, indanthrene brilliant orange RK, pendidine orange G, indanthrene brilliant orange GK.

Red pigment Bengala, Cadmium red, Lead red, Cadmium mercury sulfide, Permanent orange 4R, Risor red, Pyrazolone red, Watching red calcium salt, Lake red D, Brilliand carmine 6B, Eosin lake, Rhodamine lake B, Alizarin lake , Brilliant Carmin 3B.

Purple pigment Manganese purple, fast violet B, methyl violet lake.

Blue pigment Navy blue, cobalt blue, alkali blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalohistinine blue, partially chlorinated phthalocyanine blue, first sky blue, indansu blue B
C.

Green pigments chrome green, chromium oxide, pigment green B, malachite green lake, fanal yellow green G.

White pigment Zinc white, titanium oxide, antimony white, zinc sulfide.

Constituent pigment Parite powder, barium carbonate, clay, silica, white carbon, talc, aluminum white.

These color pigments are preferably used in an amount of 0.1 to 50 parts by weight, particularly preferably 1 to 20 parts by weight, based on 100 parts by weight of the polymerizable monomer.

Further, a magnetic material pigment may be blended to impart magnetism to the toner.

As a magnetic material pigment, for example, triiron tetroxide (Fe
₃ O ₄ ), iron sesquioxide (γ-Fe ₂ O ₃ ), zinc iron oxide (ZnFe ₂ O
₄ ), yttrium iron oxide (Y ₃ Fe ₅ O ₁₂ ), cadmium oxide (Gd ₃ Fe ₅ O ₁₂ ), copper iron oxide (CuFe ₂ O ₄ ), lead iron oxide (Pb
Fe ₁₂ O ₁₉ ), iron neodymium oxide (NdFeO ₃ ), barium iron oxide (BeFe ₁₂ O ₁₉ ), magnesium iron oxide (MgFe ₂ O ₄ ),
Manganese iron oxide (MnFe ₂ O ₄ ), iron lanthanum oxide (LaFe
O ₃ ), iron powder (Fe), cobalt powder (Co), nickel powder (N
Although i) and the like are known, any of these known fine powders of a magnetic material can be used in the present invention. These magnetic material pigments are made of the polymerizable monomer 100 described above.
It is preferable to add 1 to 200 parts by weight, especially 5 to 100 parts by weight based on parts by weight.

Further, as the charge controlling dye to be mixed with the polymerizable monomer, known charge controlling dyes used in this field, for example, oil-soluble dyes such as oil black, higher fatty acids, resin acids and the like Manganese, iron, cobalt, lead,
Metal soaps such as zinc, cerium, calcium, nickel, etc., and chromium, copper, iron, cobalt, nickel,
Metal complex salt azo dyes containing a metal such as aluminum, and metal complex salt compounds such as zinc and chromium such as salicylic acid, alkyl salicylic acid and naphthenic acid can also be mentioned. Among these, metal-containing complex azo dyes are used because they are excellent in immobilization with a binder resin, and among these, alcohol-soluble dyes are preferably used. These charge controlling dyes are preferably added in an amount of 0.1% by weight or more, particularly about 0.1 to 3% by weight, based on 100 parts by weight of the polymerizable monomer. If the amount is less than 0.1% by weight, the dye concentration on the toner surface will be excessively reduced in the immersion treatment of the toner particles in an organic solvent, which will be described later.

In the present invention, in addition to the above-mentioned coloring agent and charge controlling dye, various compounding agents known per se used in this field can be compounded.

For example, low-molecular-weight polypropylene, low-molecular-weight polyethylene, various waxes such as paraffin wax as an anti-offset agent, an olefin polymer having 4 or more carbon atoms,
Fatty acid amide, silicone oil, etc.
0.1 to 10 parts by weight can be contained per 0 parts by weight.

Also, for the purpose of controlling the charge other than the charge control dye,
A charge controlling resin may be blended. In this case, the charge control resin is a resin component having the above-described monomer having a polar group as a component, and a homopolymer of a monomer having a polar group or a monomer having a polar group and another A copolymer obtained by previously synthesizing a copolymer with an addition polymerization type monomer by solution or bulk polymerization is used. These charge controlling resins are preferably used in an amount of about 0.1 to 10 parts by weight per 100 parts by weight of the polymerizable monomer.

As the dispersion stabilizer when the polymerizable composition in which various compounding agents are mixed with the polymerizable monomer is added to the aqueous phase and suspended and dispersed, a dispersion stabilizer used in suspension polymerization known per se is used. Although an inorganic dispersant can be used, an inorganic dispersant is preferable from the viewpoint of the stability of the particles and the ease of removal from the polymer particles after polymerization, and particularly, a poorly water-soluble inorganic salt fine powder is used. Specific examples include calcium sulfate, tricalcium phosphate, magnesium carbonate, barium carbonate, calcium carbonate, aluminum hydroxide, silica and the like. The dispersant is preferably used in an amount of about 0.001 to 10 parts by weight, particularly about 0.005 to 5 parts by weight, based on 100 parts by weight of water.

Examples of the polymerization initiator include azo compounds such as azobisisobutyronitrile, cumene hydroperoxide, t-butyl hydroperoxide, dicumyl peroxide, di-t
Oil-soluble initiators such as peroxides such as -butyl peroxide, benzoyl peroxide, lauroyl peroxide and the like are used.
In addition, combinations with ionizing radiation such as γ-rays and accelerated electron beams and various sensitizers are also used.

The reaction conditions can be appropriately selected, but the stirring speed for generating dispersed oil droplets is generally 3000 to 200,000 rpm,
The stirring is particularly preferably 5000 to 15000 rpm, and the mixture is stirred so that the particle size of the suspended oil droplets is adjusted to 5 μm to 11 μm, particularly 7 μm to 10 μm. The compounding amount of the polymerization initiator such as an azo compound and a peroxide may be a so-called catalyst suitable amount, and is generally preferably used in an amount of 0.1 to 10% by weight per charged monomer. The polymerization initiation temperature and time may be those known in the art, and generally, polymerization at a temperature of 40 to 100 ° C. for 1 hour to 50 hours is sufficient. The stirring of the reaction system may be gentle stirring so that a homogeneous reaction occurs as a whole, and the polymerization is carried out by replacing the reaction system with an inert gas such as nitrogen to prevent the polymerization from being inhibited by oxygen. You may. The polymerization product after the reaction is solid-liquid separated by filtration, taken out, washed with water, treated with a dilute acid and the like to obtain toner particles. As described above, according to the suspension polymerization method described above, the toner of the present invention can be efficiently manufactured in a short time, but if the toner having the above-described roundness and surface dye concentration can be obtained. It may be manufactured by any method. For example, styrene
It can be produced by a so-called spray dry method of dissolving or dispersing in a binder resin such as an acrylic copolymer, a polyester resin or an epoxy resin and a coloring agent, a charge controlling dye and an organic solvent such as toluene and spray granulation. The toner particles is in the range of circularity described above, the median diameter D ₅₀ of 5 to 11μm on a volume basis, preferably in the 7 to 10μm range, the D ₂₅ / D ₇₅ further represents a degree of dispersion of the particle size 1.2
Adjust so that it is in the range of 1.6 to 1.6. When the toner has the above-mentioned particle size characteristics, the fluidity and the agitation properties of the toner particles are improved, the charging characteristics are improved, and the toner image has a very high resolution and a sharp image.

Immersion treatment of toner in organic solvent In the immersion and stirring operation of toner particles in an organic solvent to adjust the dye concentration of the toner, the charge control dye is dissolved or dispersed as the organic solvent used, but is bound. The resin does not dissolve, and specific examples include methanol, ethanol, propanol, isobutanol, and tert.
Alcohols such as butanol, hexanol and octanol, n-hexane, pentane, heptane, octane, isooctane, decane, 2,2′-dimethylbutane,
Aliphatic hydrocarbons such as cyclohexane, dichloromethane,
Dichloroethane, carbon tetrachloride, carbon halides such as chlorobenzene, ethers such as dioxane, dimethyl ether, diethyl ether and tetrahydrofuran, ketones such as acetone, methyl ethyl ketone and cyclohexanone, acetonitrile, formaldehyde, dimethylformamide and the like. Alternatively, two or more kinds are used in combination. Toner particles having a surface dye concentration of a predetermined concentration or more are immersed in these organic solvents, and the surface dye concentration is from 1 × 10 ^{-3 to} 4 × 10 ^-3 g / g while washing unnecessary dye on the surface while stirring. , Especially 1.5 × 10 ^{-3 to} 3 × 10
^-3 g / g. At this time, since the surface charge controlling dye is dispersed in a state of covering the particle surface, the concentration of the dye that effectively works for triboelectric charging can be suppressed to a very small amount.

The stirring speed may be a gentle stirring operation of generally 30 to 100 rpm, and the treatment time may be about 0.01 to 60 hours.

Thereafter, the toner is taken out of the solvent and dried to obtain a final toner.

The spherical toner of the present invention having a roundness of 0.95 to 1 and a surface dye concentration of 1 × 10 ⁻³ to 4 × 10 ⁻³ g / g can be used as fine particles of metal oxide such as hydrophobic silica and alumina or polystyrene. And
It may be used as a toner composition by mixing with resin fine particles such as PMMA.

Magnetic carrier When the toner of the present invention is mixed with a magnetic carrier and used as a two-component developer, a magnetic carrier known per se used in this field can be used, but generally, ferrite particles capable of forming a soft magnetic brush are used. Ferrite particles, which are preferably used and have a high resistance resin coating layer on the particle surface, are more preferably used.

The ferrite particles are preferably spherical, and the particle diameter is preferably in the range of 20 to 150 μm, particularly 50 to 120 μm. Ferrite includes zinc iron oxide (ZnFe ₂ O ₄ ), yttrium iron oxide (Y ₃ Fe ₅ O ₁₂ ), cadmium oxide (Gd ₃ Fe ₅ O ₁₂ ), copper iron oxide (CuFe ₂ O ₄ ), and lead iron oxide (PbFe ₁₂ O ₁₉ ), neodymium iron oxide (NdFeO ₃ ), barium iron oxide (BeFe ₁₂ O ₁₉ ), magnesium iron oxide (MgF
₂ O ₄ ), iron manganese oxide (MnFe ₂ O ₄ ), lanthanum iron oxide (LaFeO ₃ ), and the like, and sintered ferrite particles having a composition of one or two or more kinds are used. In particular, Cu, Zn, Mg, Mn
And a soft ferrite containing one or more metal components selected from the group consisting of Ni and Ni, preferably copper-zinc-magnesium ferrite.

As a coating resin for surface coating, silicone resin, fluorine resin, acrylic resin, styrene resin, styrene-acryl resin, olefin resin,
One or more of phenolic resins and the like are used.

The toner of the present invention is used as a developer by adjusting the concentration of the magnetic carrier and the toner so as to be 2 to 10%, particularly 3 to 8%.

 Hereinafter, the present invention will be described with reference to Examples and Comparative Examples.

(Example 1) Styrene 80 parts by weight 2-ethylhexyl methacrylate 20 parts by weight Grafted carbon black 5 parts by weight Chromium-containing complex salt azo dye Spiron Black TRH (trade name, manufactured by Hodogaya Chemical Co., Ltd.) 1 part by weight Divinylbenzene 0.5 part by weight Parts by weight ADVN 2 parts by weight The above mixture is used as a polymerizable composition, and the mixture is poured into 480 parts by weight of water containing 0.086% of tricalcium phosphate and 0.005% of sodium dodecylbenzenesulfonate as a dispersion stabilizer, and TK
Using a homomixer (manufactured by Tokushu Kika Kogyo) at 11500 rpm
The suspension was suspended for 10 minutes and polymerized at 80 ° C. for 10 hours under a nitrogen atmosphere to obtain a suspension containing polymer particles. When the obtained particles were measured by a Coulter counter, the volume-based median diameter was 9.8 μm, and the degree of dispersion represented by D ₂₅ / D ₇₅ was 1.47. The roundness calculated by the image analyzer is 0.98
Met. The particles were washed with hydrochloric acid to dissolve and remove the remaining tricalcium phosphate, washed with water, further immersed and stirred in 400 parts by weight of methanol for 3 minutes, filtered and dried. The measured surface dye concentration of this toner was 2.6 × 10 ⁻³ g / g. A developer was prepared at a toner concentration of 3% using this toner and a ferrite carrier, and subjected to a printing durability test at room temperature and normal humidity and under high temperature and high humidity using a copying machine DC-111C (manufactured by Mita Industries). There was almost no change in the image quality and the amount of charge throughout the 10,000 sheets, and a clear image was always obtained. Further, there was almost no contamination by the magnetic carrier or the dye in the developing device.

 The results are shown in Tables 1 and 2.

(Example 2) Polymerization was carried out in the same manner as in Example 1 except that the amount of the charge control dye "Spiron Black TRH" was changed to 0.3 part by weight, and the washing operation in methanol was not carried out. After washing with hydrochloric acid, washing with water and drying, a toner was obtained. The surface dye concentration of the obtained toner was 2.5 × 10 ⁻³ g / g, the volume-based median diameter was 10.2 μm, the degree of dispersion (D ₂₅ / D ₇₅ ) was 1.46, and the roundness was 0.99. Further, a printing durability test was performed in the same manner as in Example 1. As a result, even after the printing durability of 20,000 sheets, the change in the image quality and the charge amount was small and was at an appropriate level. Also, there was almost no contamination of the magnetic carrier and the developing device by the dye. The results are shown in Tables 1 and 2.

Example 3 A toner was prepared in the same manner as in Example 1 except that 1 part by weight of "Bontron E-84" (manufactured by Orient Chemical Co., Ltd.), which is a zinc complex salt of alkyl salicylic acid, was used as a charge controlling dye. The surface dye concentration of the obtained toner is 2.9 × 10 ⁻³ g /
g, the volume-based median diameter was 8.9 μm, the degree of dispersion was 1.52, and the roundness was 0.99. Further, a printing durability test was carried out in the same manner as in Example 1. As a result, even after printing for 20,000 sheets, changes in image quality and charge amount were small and were at an appropriate level. Further, there was almost no contamination of the magnetic carrier and the developing device by the dye. The results are shown in Tables 1 and 2.

(Example 4) "Bontron E-82" (manufactured by Orient Chemical Co., Ltd.), which is a chromium complex dye of naphthoic acid, was used as a charge controlling dye.
A toner was prepared in the same manner as in Example 1 except that 5 parts by weight were used. The surface dye concentration of the obtained toner is 3.1 × 10 ⁻³ g /
g, volume-based median diameter is 11.5 μm, dispersity is 1.55,
The roundness was 0.96. Further, a printing durability test was carried out in the same manner as in Example 1. As a result, even after printing for 20,000 sheets, changes in image quality and charge amount were small and were at an appropriate level. Further, there was almost no contamination of the magnetic carrier and the developing device by the dye. The results are shown in Tables 1 and 2.

(Example 5) Styrene-acrylic copolymer 100 parts by weight Grafted carbon black 8 parts by weight "Bontron S-34" which is a chromium-containing complex azo dye as a charge control dye (manufactured by Orient Chemical Co.) 1 part by weight Low molecular weight A resin solution was prepared by dissolving and dispersing 0.5 parts by weight of polypropylene "Viscol 550P" (manufactured by Sanyo Chemical Industries, Ltd.) in toluene, and spray-granulated by a spray dry method to prepare a toner. The surface dye concentration of the obtained toner was 1.9 × 10 ⁻³ g / g, the volume-based median diameter was 7.1 μm, the degree of dispersion was 1.51, and the roundness was 0.96. Further, a printing durability test was carried out in the same manner as in Example 1. As a result, even after printing for 20,000 sheets, changes in image quality and charge amount were small and were at an appropriate level. Further, there was almost no contamination of the magnetic carrier and the developing device by the dye. The results are shown in Tables 1 and 2.

(Comparative Example 1) Styrene-acrylic copolymer 100 parts by weight Grafted carbon black 8 parts by weight "Bontron S-34" which is a chromium-containing complex azo dye as a charge control dye (manufactured by Orient Chemical Co.) 1.5 parts by weight Low molecular weight 0.5 parts by weight of polypropylene "Viscol 550P" (manufactured by Sanyo Kasei Co., Ltd.) was mixed with a Henschel mixer and melt-kneaded by a twin screw extruder. A toner having a dispersion degree of 1.45 and a roundness of 0.79 was prepared.

The obtained toner was immersed and stirred in methanol in the same manner as in Example 1 to adjust the surface dye concentration to 2.3 × 10 ⁻³ g / g. Further, a printing durability test was carried out in the same manner as in Example 1. As a result, although there was almost no contamination of the magnetic carrier or the inside of the developing device with the dye, image fog and a decrease in resolution were observed, and toner scattering occurred. The results are shown in Tables 1 and 2.

(Comparative Example 2) A toner was prepared in the same manner as in Example 1 except that the immersion and stirring treatment in methanol was not performed. The surface dye concentration of this toner is 4.3 × 10 ^-3 g / g, and the volume-based median diameter is
9.8 μm, the degree of dispersion was 1.45, and the roundness was 0.98. Further, a printing durability test was performed in the same manner as in Example 1. As a result, image fogging occurred as the number of printing durability increased. Further, the adhesion of the dye was remarkable on the surface of the magnetic carrier, and the toner was scattered under a high temperature and high humidity environment. The results are shown in Tables 1 and 2.

Comparative Example 3 A toner having a surface dye concentration of 0.8 × 10 ⁻³ g / g was prepared by excessively immersing and stirring in methanol in Example 1. The volume-based median diameter of this toner is 9.8μ
m, the degree of dispersion was 1.48, and the roundness was 0.98. Further, a printing durability test was performed in the same manner as in Example 1. As a result, as the number of printing durability increased, image fog and image density decreased. The results are shown in Tables 1 and 2.

As is clear from Tables 1 and 2, the toner of the present invention has a small variation in the charge amount and has a stable developing property, so that the image density can be obtained even under normal temperature and normal humidity and high temperature and high humidity. It can be seen that a good image having a high resolution and no fogging can be obtained. Further, compared to the case where the toner of the comparative example is used, the friction members such as the carrier and the inside of the developing device are less likely to be contaminated. Furthermore, it is found that the one subjected to the immersion cleaning treatment in the organic solvent has better durability and environmental resistance.

(Effects of the Invention) According to the present invention, by adjusting the particle morphology and the surface dye concentration of the toner to specific ranges, the charge control dye can be prevented from falling off and the charge stability can be improved. A toner excellent in chargeability, durability, environmental stability, and developability can be obtained, and a high-quality image can be formed.

Claims (7)

(57) [Claims] An electrostatic image developing toner in which at least a colorant and a charge controlling dye are dispersed in a binder resin, wherein the spherical particles have a roundness of 0.95 to 1.0 represented by the following formula,
A toner for developing electrostatic images, wherein the surface dye concentration is 1 × 10 ^{−3 to} 4 × 10 ⁻³ g / g. Wherein, r _l represent the major axis of the toner particles, r _s represents the minor axis of the toner particles. 2. A method of immersing spherical particles in an organic solvent in which a charge controlling dye is dissolved to reduce the surface dye concentration to 1 × 10 5
^2. The electrostatic image developing toner according to claim 1, wherein the toner is adjusted to ^{-3 to} 4 * 10 < ^-3 > g / g. 3. The spherical particles have a volume-based median diameter of 5
Or at 11μm, D ₂₅ / D ₇₅ representing the degree of dispersion of the particle diameter of 1.2 to
2. The electrostatic image developing toner according to claim 1, wherein the ratio is 1.6. 4. The toner according to claim 1, wherein said spherical particles are polymer particles directly produced by a suspension polymerization method. 5. After producing spherical particles having a roundness of 0.95 to 1.0 represented by the formula (1) in which at least a colorant and a charge controlling dye are dispersed in a binder resin, the charge controlling dye is The spherical particles are immersed in an organic solvent that dissolves or disperses but does not dissolve the resin component, and the charge controlling dye is uniformly attached to the entire surface of the spherical particle while washing off unnecessary portions of the charge controlling dye existing on the particle surface. A method for producing an electrostatic image developing toner. 6. The method for producing a toner for developing electrostatic images according to claim 5, wherein the final dye concentration on the surface of the particles is adjusted to 1 × 10 ^{−3 to} 4 × 10 ⁻³ g / g. 7. A polymerizable composition comprising at least a polymerizable monomer, a colorant, and 0.1% by weight or more of a charge controlling dye based on the polymerizable monomer, for suspension polymerization of the spherical particles. The volume-based median diameter obtained by the above is 5 to 11μ
7. The method for producing a toner for developing an electrostatic charge image according to claim 5, wherein m is a polymer particle having a degree of dispersion of particle diameter, D ₂₅ / D ₇₅ of 1.2 to 1.6.