JP2805355B2 - Negatively charged electrostatic image developing toner - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a negatively charged electrostatic image development for visualizing an electrostatic latent image in an image forming method such as electrophotography and electrostatic recording. Related to toner.

[Prior Art] Conventionally, as an electrophotographic method, US Pat. No. 2,297,691,
Various methods are described in JP-B-42-23910 and JP-B-43-24748.

Developing methods applied to the electrophotographic method and the like are roughly classified into a dry developing method and a wet developing method. The former is further classified into a method using a two-component developer and a method using a one-component developer.

Conventional toners applied to these dry development methods include:
Fine powders in which dyes and pigments are dispersed in natural or synthetic resins are used. For example, particles obtained by dispersing a colorant in a binder resin such as polystyrene and the like are finely pulverized to about 1 to 30 μm are used as toner. As the magnetic toner, a toner containing magnetic particles such as magnetite is used. In the case of using a two-component developer, the toner is usually used by being mixed with carrier particles such as glass beads and iron powder.

Any toner must have a positive or negative charge, depending on the polarity of the electrostatic latent image to be developed. For that purpose, it is common to add a compound called a charge control agent.

Further, various chemical substances are added according to the fixing property of the image and other required characteristics.

In particular, for the purpose of improving various image characteristics such as resolution, density uniformity and fogging, external addition of silica fine powder has been widely performed to impart fluidity to toner.

[Problem to be Solved by the Invention] However, although the above problem is improved by external addition of silica fine powder, a new problem of environmental dependency of image quality arises. For this purpose, the present situation is that some heaters are provided in the copying machine or other additives are externally added, so that the copier can be managed. However, remodeling of the copying machine itself leads to an increase in price, and the use of other external additives often causes new problems. In particular, this is the biggest problem in a full-color copying machine that needs to faithfully reproduce a halftone image. Therefore, there is a strong demand in the art for the development of a silica fine powder that significantly reduces the environmental fluctuation of the toner when externally added.

An object of the present invention is to provide a negatively chargeable electrostatic image developing toner which has solved the above problem.

That is, it is an object of the present invention to provide a negatively chargeable electrostatic image developing toner which has little environmental dependency and good reproducibility of a halftone image.

[Means and Actions for Solving the Problems] Specifically, the present invention relates to a method in which a toner particle comprising at least a colorant and a binder resin is provided with (i) an amino group, a nitrogen-containing heterocyclic group and a phosphorus-containing organo group. Negatively-charged, characterized by externally adding negatively-chargeable silica fine powder treated with a silane coupling agent having a positively-chargeable site selected from the group consisting of: (ii) a negatively-chargeable site; The present invention relates to a toner for developing an electrostatic image.

 Hereinafter, the present invention will be described in detail.

Generally, in order to obtain a toner having good environmental stability, the conventional idea has been to suppress the water absorption of silica and to stabilize the triboelectric charge of silica itself. Such an example is disclosed in JP-A-49-42354 for treating silica with silicone oil, and Japanese Patent Publication No. 54-16219 for externally adding hydrophobic silica to a toner.
JP-A-56-123550 discloses a method of externally adding silica treated with a silane coupling agent to a toner. Thus, prior developments have focused solely on treating agents and methods for hydrophobizing silica.

The present inventors have confirmed that the largest cause of environmental instability of the toner is due to environmental fluctuations in the triboelectric charge amount of the toner.
It has also been found that, even with toner not externally added with silica, the amount of triboelectric charge changes due to environmental fluctuations, and external addition of silica further increases this. Environmental fluctuation of the triboelectric charge of toner
Although the degree varies depending on the type of toner carrier such as a carrier or a sleeve, silica is most influential.

As described above, the amount of triboelectric charge of silica-non-externally added toner also changes depending on the environment.Therefore, in order to eliminate the dependence of the triboelectric charge of the toner on the environment, the triboelectric charge of silica itself has no environmental fluctuation. It is insufficient and needs to be changed so as to offset the change of the toner not externally added with silica. Further, silica having a high absolute value of the triboelectric charge is not preferable from the viewpoint of stabilizing the environment of the toner. Here, silica having a high triboelectric charge means a tribular charge with iron powder (EFV200 / 300 made by Nippon Iron Powder) in a ratio of silica to iron powder of 3: 100 and a turbula shaker / mixer T2C type (manufactured by WAB). ) Is measured by the blow-off method after shaking for 60 seconds, | -150 | μc / g
The above is mentioned.

The present inventors have newly found the above-mentioned knowledge, and have developed silica having low frictional chargeability, and the amount of frictional charge decreases as the humidity decreases.

As a result of diligent research, negative triboelectrically-charged silica fine powder treated with a silane coupling agent having both positive triboelectric and negative triboelectric charging sites has low triboelectric charging characteristics and low triboelectric charging characteristics as the humidity decreases. The present invention was completed by finding that it was reduced.

According to the present invention, as the silica fine powder before treatment with the silane coupling agent, dry silica, wet silica can be used, but for the purpose of imparting the inherent flowability of silica, dry silica Is more preferred.

The dry method referred to herein is a method for producing silica fine powder generated by vapor phase oxidation of a silicon halide derivative. For example, in a method utilizing the thermal decomposition oxidation reaction of silicon tetrachloride gas in oxygen-hydrogen, the basic reaction formula is as follows.

SiCl ₄ + 2H ₂ + O ₂ → SiO ₂ + 4HCl In this production process, for example, by using other metal halogen derivatives such as aluminum chloride and titanium chloride together with the silicon halogen derivative, a composite fine powder of silica and another metal oxide is obtained. It is also possible to include these.

On the other hand, as a method for producing the silica fine powder used in the present invention by a wet method, various conventionally known methods can be applied. For example, decomposition of sodium silicate with an acid, as represented by a general reaction formula (hereinafter, the reaction formula is abbreviated), Na ₂ O · XSiO ₂ + HCl + H ₂ O → SiO ₂ · nH ₂ O + NaCl, etc., and ammonium salts or alkalis of sodium silicate Decomposition with salts, after producing an alkaline earth metal silicate from sodium silicate, a method of decomposing with an acid to silicic acid, a method of converting a sodium silicate solution to silicic acid with an ion exchange resin, natural silicic acid or There is a method using a silicate.

Silica such as aluminum silicate, sodium silicate, potassium silicate, magnesium silicate, zinc silicate and the like can be applied to the silica fine powder here, in addition to anhydrous silicon dioxide (silica).

Among the above silica fine powders, those having a specific surface area of 30 m ² / g or more (particularly 50 to 400 m ² / g) measured by the BET method by nitrogen adsorption give good results.

Examples of the organic group that can be a positive triboelectrification site of the silane coupling agent include an amino group and a nitrogen-containing heterocyclic group. As the nitrogen-containing heterocyclic group, there are an unsaturated heterocyclic group and a saturated heterocyclic group, each of which can be applied. Examples of the unsaturated heterocyclic group include the following.

Examples of the saturated heterocyclic group include the following.

Also, nitrogen-containing salt compounds such as quaternary ammonium salts and pyridinium salts can be exemplified. Further, phosphines, phosphonium salts and the like can be exemplified. However, an amino group and a nitrogen-containing heterocyclic group are preferable in consideration of easiness of synthesis and cost.

Various organic groups can be exemplified as the organic group that can serve as the negative triboelectric charging site of the silane coupling agent.

For example, conventional silane coupling agents whose organic groups do not have nitrogen or phosphorus are negatively triboelectrically chargeable. this is,
It is thought to be caused by the Si-C bond, but it is very preferable to use this as a negative triboelectrification site. However, in this case, the negative triboelectrification due to the Si—C bond decreases with an increase in the number of carbon atoms of the hydrocarbon directly bonded to Si. Therefore, in the case of the present invention, the methylene group (—CH ₂ —) or An ethylene group (—CH ₂ CH ₂ —) is preferred.

In addition, an organic acid such as carboxylic acid and sulfonic acid, or an organo group having an acidic hydroxy group such as phenol can be used to positively provide a negative triboelectric charging site in the silane coupling agent.

Further, by using a halogen atom, a carbonyl group, a sulfonyl group, a cyano group, or the like, a negative triboelectric charging site can be provided in the silane coupling agent.

One of the features of the present invention is that a negative frictionally chargeable silica is obtained by a combination of a positive frictional charge portion and a negative frictional charge portion as described above.

The silane coupling agent according to the present invention can be synthesized by a conventionally known method.

Basically, a hydrohalogenosilane or a hydroalkoxysilane and a compound having an alkene portion into which the above-mentioned positive triboelectric charging site (if necessary, a negative triboelectric charging site) is introduced are allowed to act in the presence of a catalyst such as a platinum-containing compound. When using a Si-C bond as the negative triboelectric charging site, it is not necessary to act on a compound having an alkene portion into which a negative triboelectric charging site is introduced, but otherwise, the alkene portion into which a positive triboelectric charging site is introduced is used. It is necessary to cause both the compound having the compound and the compound having an alkene moiety introduced with a negative triboelectric charge site to react with hydrohalogenosilane or hydroalkoxysilane. At this time, the order of the action of the compound having an alkene moiety into which a triboelectrically charged site is introduced may be positive or negative, or may be simultaneously applied. In addition, one of the compounds having an alkene moiety into which a positive or negative triboelectric charging site is introduced is reacted with hydrohalogenosilane or hydroalkoxysilane to obtain positive and negative two kinds of silane coupling agents, respectively. May be obtained to obtain the silane coupling agent according to the present invention. Alternatively, a halogenoalkylalkoxysilane or a halogenoalkylhalogenosilane and a compound having the above-mentioned triboelectrically charged portion (if necessary, a negatively triboelectrically charged portion) may be allowed to act in the same manner as described above.

For example, in the case of diethylaminopropyltriethoxysilane, triethoxyhydrosilane and allyldiethylamine are allowed to act in the presence of a chloroplatinic acid catalyst, or chloropropyltriethoxysilane and diethylamine are acted upon, and then sodium methoxide is further actuated for purification. Can be obtained.

Representative examples of the silane coupling agent according to the present invention are shown below, but they do not limit the present invention in any way.

(1). Using a Si-C bond as a negative frictional charge site Since negative frictional chargeability based on a Si-C bond is relatively weak,
It is preferable to use a weakly positively triboelectrically-chargeable functional group such as a phenylamino group for the positively triboelectrically charged site.

(2). Halogen, carbonyl,
Those using a phenol, cyano group, etc. Since these also have relatively weak negative triboelectrification, it is preferable to use a weakly positive triboelectrification functional group such as a phenylamino group for the positive triboelectrification site.

(3). Using Organic Carboxylic Acid Derivatives as Negative Friction Charging Sites Since these negative friction charging properties are relatively strong, it is preferable to use a relatively strong positive friction charging functional group for the positive friction charging site.

(4). Obtained by the action of a silane coupling agent having a negative triboelectric charging site and a silane coupling agent having a positive triboelectric charging site The amount of the silica fine powder used in the present invention is 0.01 to 5%, preferably 0.05 to 2%, based on the weight of the toner.
It is. Further, the silicas used in the present invention may be used together or some known silicas may be used in combination.

On the other hand, as the resin for forming the toner particles used in the present invention, for example, styrene such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene and a substituted homopolymer thereof; styrene-p-chloro Styrene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylate copolymer, styrene-methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer Styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-
Styrene polymers such as isoprene copolymer and styrene-acrylonitrile-indene copolymer; polyvinyl chloride, phenolic resin, natural modified phenolic resin, natural resin modified maleic resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone Resins, polyester resins, polyurethanes, polyamide resins, furan resins, epoxy resins, xylene resins, polyvinyl butyral, terpene resins, cumarone indene resins, petroleum resins and the like can be used.

Further, a crosslinked styrene copolymer is also a preferable binder resin.

Examples of the comonomer for the styrene monomer of the styrene copolymer include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, and methacrylic. Monocarboxylic acid having a double bond such as acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide or a substituted product thereof; for example, maleic acid, butyl maleate A dicarboxylic acid having a double bond such as methyl, methyl maleate, dimethyl maleate and the like; and a vinyl ester such as vinyl chloride, vinyl acetate and vinyl benzoate;
Ethylene olefins such as propylene and butylene; vinyl ketones such as vinyl methyl ketone and vinyl hexyl ketone; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether; A single monomer or two or more monomers are used. Here, as the cross-linking agent, a derivative having two or more polymerizable double bonds is mainly used, for example, an aromatic divinyl derivative such as divinylbenzene or divinylnaphthalene; for example, ethylene glycol diacrylate or ethylene glycol diacrylate. Carboxylate having two double bonds such as methacrylate, 1,3-butanediol dimethacrylate; divinylaniline, divinyl ether, divinyl sulfide,
A divinyl derivative such as divinyl sulfone; and a derivative having three or more vinyl groups are used alone or as a mixture.

When a pressure fixing method is used, a binder resin for a pressure fixing toner can be used. For example, polyethylene, polypropylene, polymethylene, polyurethane elastomer, ethylene-ethyl acrylate copolymer, ethylene-vinyl acetate copolymer can be used. Coalescent, ionomer resin, styrene-butadiene copolymer, styrene-isoprene copolymer, linear saturated polyester, paraffin and the like.

It is also preferable to add a negative charge control agent to impart negative frictional charge to the toner particles. Any known negative charge control agent can be used without any particular limitation. Examples of such a charge control agent include a complex of a salicylic acid derivative, a complex of a monoazo derivative, a phenol derivative, an organic acid such as carboxylic acid and sulfonic acid, and a polymer having these in a side chain. In order to finely adjust the triboelectric charge of the toner particles, a slight amount of a positive charge control agent can be added. Of course, without using a charge control agent,
The frictional charging property of the binder resin can also be used.

As the coloring agent used in the present invention, carbon black, lamp black, iron black, ultramarine, nigrosine dye, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa Yellow G, rhodamine 6G, calco oil blue, chrome yellow, quinacridone, Known dyes and pigments such as benzidine yellow, rose bengal, triarylmethane dyes, monoazo dyes and disazo dyes can be used alone or in combination.

Further, the toner of the present invention is used by being mixed with a carrier. As the carrier that can be used in the present invention, known carriers can be used, for example, iron powder, ferrite powder, powder having magnetic properties such as nickel powder, glass beads, and the like, and the surface thereof is treated with a resin or the like. What was done.

Further, as the resin for coating the carrier surface, styrene-acrylate copolymer, styrene-methacrylate copolymer, acrylate copolymer,
A methacrylate copolymer, a silicone resin, a fluorine-containing resin, a polyamide resin, an ionomer resin, a polyphenylene sulfide resin, or a mixture thereof can be used.

Further, the toner for electrostatic charge development of the present invention can be used as a magnetic toner by containing a magnetic material. Examples of the magnetic material used include magnetite, γ-iron oxide, ferrite, iron oxides such as iron-rich ferrite; metals such as iron, cobalt, and nickel; or these metals and aluminum, cobalt, copper, lead, magnesium, tin, and the like. Examples thereof include alloys with metals such as zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, and vanadium, and mixtures thereof. These magnetic materials preferably have an average particle diameter of 0.1 to 1 μm, and preferably about 0.1 to 0.5 μm. The amount contained in the magnetic toner is 40 to 150 parts by weight based on 100 parts by weight of the binder resin component. Parts, preferably 60 to 120 parts by weight.

The toner of the present invention may optionally contain additives. Examples of the additive include a lubricant such as zinc stearate, a polishing agent such as cerium oxide and silicon carbide, a fluidity imparting agent such as aluminum oxide, an anti-caking agent, and a conductivity imparting agent such as carbon black and tin oxide. There are agents.

Fluorine-containing polymer fine powder such as polyvinylidene fluoride fine powder is also a preferable additive from the viewpoint of fluidity, abrasiveness, charge stability and the like.

Further, in order to improve the releasability at the time of hot roll fixing, a wax-like substance such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, carnauba wax, sasol wax, paraffin wax, etc.
Addition of about 5% by weight to the toner is also a preferred embodiment of the present invention.

In producing the toner according to the present invention, the above-mentioned toner constituent materials are sufficiently mixed by a ball mill or other mixer, then kneaded well using a hot kneader of a hot roll kneader or an extruder, and cooled and solidified. A method of obtaining a toner by mechanical pulverization and classification is preferable. Alternatively, a method of obtaining a toner by dispersing a constituent material in a binder resin solution and spray-drying; or forming a binder resin A polymerization method in which a predetermined material is mixed with a monomer to form an emulsified suspension and then polymerized to obtain a toner;
Alternatively, in a so-called microcapsule toner composed of a core material and a shell material, a method of including a predetermined material in the core material, the shell material, or both of them can be applied. Further, if necessary, the desired additive is sufficiently mixed with a mixer such as a Henschel mixer to produce the toner according to the present invention.

The toner of the present invention can be used for development for visualizing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing, and the like, by a conventionally known means.

[Examples] Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto. All parts in the following formulations are parts by weight.

Example 1 After the above materials were mixed well in a blender, they were kneaded with a biaxial kneading extruder set at 150 ° C. The obtained kneaded material was cooled, coarsely pulverized by a cutter mill, and then finely pulverized using a fine pulverizer using a jet stream, and the obtained finely pulverized powder was classified by a fixed wall type air classifier. The classified powder was purified.

Further, the obtained classified powder is strictly classified and removed simultaneously and simultaneously with a multi-division classifier utilizing a Coanda effect (an elbow jet classifier manufactured by Nittetsu Mining Co., Ltd.) to obtain a volume average particle size of 8.8 μm. A black fine powder (that is, toner particles) was obtained.

On the other hand, silica fine powder Aerosil 200 (manufactured by Nippon Aerosil Co., Ltd.) was treated with the silane coupling agent shown in Compound Example (1-1) (at a temperature of 150 ° C. for a treatment time of 2 hours) to obtain a silica fine powder of the present invention. I got a body.

0.5% of this silica fine powder was externally added to the above black fine powder to obtain a toner.

Acrylic-coated ferrite carrier with an average particle size of 65 μm
6 parts of the obtained toner was mixed with respect to 100 parts to prepare a developer.

Next, using a commercially available color copying machine CLC-1 (manufactured by Canon Inc.), a copy test of this toner was performed without environmental correction.

The image obtained under the environment of 23 ° C and 60% R / H has a density of 1.45.
It was clear enough and high. Further, the uniformity of the density of the solid image and the reproducibility of the halftone image were excellent. Furthermore, images were obtained under the environment of 15 ° C., 10% R / H and 30 ° C., 85% R / H, respectively, and the image density was 1.42 and 1.46, respectively. In addition, the image quality such as the density uniformity of the solid image and the reproducibility of the halftone image did not change due to the environmental change.

Table 1 shows the environmental fluctuation of the triboelectric charge amount of silica and the toner before and after the external addition of silica. It can be seen that silica successfully compensates for the environmental fluctuation of the triboelectric charge amount of the toner before the external addition of silica.

Example 2 A toner was obtained in the same manner as in Example 1, except that 5 parts of carbon black in Example 1 was changed to 4 parts of a copper phthalocyanine pigment (CI Pigment Blue 15).

On the other hand, silica fine powder Aerosil 200 (manufactured by Nippon Aerosil Co., Ltd.) was treated with the silane coupling agent shown in Compound Example (1-2) (temperature: 150 ° C., treatment time: 2 hours) to produce silica fine powder of the present invention. I got a body.

0.5% of this silica fine powder was externally added to the above blue fine powder to obtain a toner.

Acrylic-coated ferrite carrier with an average particle size of 65 μm
6 parts of the obtained toner was mixed with respect to 100 parts to prepare a developer.

This developer was subjected to a copy test in exactly the same manner as in Example 1.

The image obtained under the environment of 23 ° C and 60% R / H has a density of 1.43
It was clear enough and high. Further, the uniformity of the density of the solid image and the reproducibility of the halftone image were excellent. Further, images were obtained under the environment of 15 ° C., 10% R / H and 30 ° C., 85% R / H, respectively, and the image density was 1.42 and 1.44, respectively. In addition, the image quality such as the density uniformity of the solid image and the reproducibility of the halftone image did not change due to the environmental change.

Table 1 shows the environmental fluctuation of the triboelectric charge amount of silica and the toner before and after the external addition of silica. It can be seen that silica successfully compensates for the environmental fluctuation of the triboelectric charge amount of the toner before the external addition of silica.

Example 3 A toner was obtained in the same manner as in Example 1, except that 5 parts of carbon black in Example 1 was changed to 3.5 parts of a quinacridone pigment (CI Pigment Red 122).

The silica fine powder used in Example 2 was used as the red fine powder described above.
0.5% was externally added to obtain a toner.

Acrylic-coated ferrite carrier with an average particle size of 65 μm
6 parts of the obtained toner was mixed with respect to 100 parts to prepare a developer.

This developer was subjected to a copy test in exactly the same manner as in Example 1.

The image obtained under the environment of 23 ° C and 60% R / H has a density of 1.46.
It was clear enough and high. Further, the uniformity of the density of the solid image and the reproducibility of the halftone image were excellent. Furthermore, images were obtained under the environment of 15 ° C., 10% R / H and 30 ° C., 85% R / H, respectively, and the image density was 1.44 and 1.48, respectively. In addition, the image quality such as the density uniformity of the solid image and the reproducibility of the halftone image did not change due to the environmental change.

Table 1 shows the environmental fluctuation of the triboelectric charge amount of silica and the toner before and after the external addition of silica. It can be seen that silica successfully compensates for the environmental fluctuation of the triboelectric charge amount of the toner before the external addition of silica.

Example 4 A toner was obtained in the same manner as in Example 1, except that 5 parts of carbon black in Example 1 was changed to 175 parts of CI Pigment Yellow.

The silica fine powder used in Example 2 was replaced with the yellow fine powder described above.
0.5% was externally added to obtain a toner.

Acrylic-coated ferrite carrier with an average particle size of 65 μm
6 parts of the obtained toner was mixed with respect to 100 parts to prepare a developer.

This developer was subjected to a copy test in exactly the same manner as in Example 1.

The image obtained under the environment of 23 ° C and 60% R / H has a density of 1.41
It was clear enough and high. Further, the uniformity of the density of the solid image and the reproducibility of the halftone image were excellent. Furthermore, images were obtained under the environment of 15 ° C., 10% R / H and 30 ° C., 85% R / H, respectively, and the image density was 1.38 and 1.42, respectively. In addition, the image quality such as the density uniformity of the solid image and the reproducibility of the halftone image did not change due to the environmental change.

Table 1 shows the environmental fluctuation of the triboelectric charge amount of silica and the toner before and after the external addition of silica. It can be seen that silica successfully compensates for the environmental fluctuation of the triboelectric charge amount of the toner before the external addition of silica.

Example 5 Black, cyan, magenta, and black used in Examples 1 to 4
When a full-color image was obtained using the yellow developer, a vivid full-color image excellent in color mixing and gradation was obtained. In addition, excellent images having no difference were obtained in all the above-mentioned environments without special measures for the copying machine body.

Comparative Example 1 A toner was obtained and a copy test was performed in the same manner as in Example 1 except that 0.5% of the silica fine powder used in Example 1 was changed to 0.5% of silica fine powder treated with dimethyldichlorosilane.

A good image with a density of 1.38 was obtained under the environment of 23 ° C and 60% R / H, but decreased to 1.05 under the environment of 15 ° C and 10% R / H. This is due to the fact that the amount of triboelectric charge has increased as shown in Table 1.

Example 6 After the above materials were mixed well in a blender, they were kneaded with a biaxial kneading extruder set at 150 ° C. The obtained kneaded material was cooled, coarsely pulverized by a cutter mill, and then finely pulverized using a fine pulverizer using a jet stream, and the obtained finely pulverized powder was classified by a fixed wall type air classifier. The classified powder was purified.

Further, the obtained classified powder is strictly classified and removed simultaneously by a multi-division classifier using a Coanda effect (an elbow jet classifier manufactured by Nippon Steel Mining Co., Ltd.) to obtain a volume average particle diameter of 12.8 μm. A black fine powder (that is, toner particles) was obtained.

On the other hand, silica fine powder Aerosil 200 (manufactured by Nippon Aerosil Co., Ltd.) was treated with the silane coupling agent shown in Compound Example (2-1) (at a temperature of 150 ° C. for a treatment time of 2 hours) to obtain a silica fine powder of the present invention. I got a body.

0.3% of this silica fine powder was externally added to the above black fine powder to obtain a toner.

Acrylic-coated ferrite carrier with an average particle size of 65 μm
5 parts of the obtained toner was mixed with respect to 100 parts to prepare a developer.

Next, using a commercially available color copying machine CLC-1 (manufactured by Canon Inc.), a copy test of this toner was performed without environmental correction.

The image obtained under the environment of 23 ° C and 60% R / H has a density of 1.42
It was clear enough and high. Further, the uniformity of the density of the solid image and the reproducibility of the halftone image were excellent. Furthermore, images were obtained under the environment of 15 ° C., 10% R / H and 30 ° C., 85% R / H, respectively, and the image density was 1.41 and 1.44, respectively. In addition, the image quality such as the density uniformity of the solid image and the reproducibility of the halftone image did not change due to the environmental change.

Example 7 After the above materials were mixed well in a blender, they were kneaded with a biaxial kneading extruder set at 150 ° C. The obtained kneaded material was cooled, coarsely pulverized by a cutter mill, and then finely pulverized using a fine pulverizer using a jet stream, and the obtained finely pulverized powder was classified by a fixed wall type air classifier. The classified powder was purified.

Further, the obtained classified powder is strictly classified and removed simultaneously with a multi-segment classification device (Elbow Jet Classifier manufactured by Nittetsu Mining Co., Ltd.) utilizing the Coanda effect to simultaneously remove ultrafine powder and coarse powder, thereby obtaining a volume average particle diameter of 11.3 μm. A black fine powder (that is, toner particles) was obtained.

On the other hand, silica fine powder Aerosil 200 (manufactured by Nippon Aerosil Co., Ltd.) was treated with the silane coupling agent shown in Compound Example (3-1) (temperature: 150 ° C., treatment time: 2 hours) to produce silica fine powder of the present invention. I got a body.

0.4% of this silica fine powder was externally added to the above black fine powder to obtain a toner.

Next, a copy test of this toner was performed using a commercially available copying machine NP-6650 (manufactured by Canon Inc.).

The image obtained under the environment of 23 ° C and 60% R / H has a density of 1.42
It was clear enough and high. Further, the uniformity of density of the solid image was also excellent. In addition, 15 ℃, 10% R / H and 30 ℃, 85% R
Although images were obtained under the environment of / H, the image density was 1.45 and 1.38, respectively. Further, no change in the image quality such as the density uniformity of the solid image due to the environmental change was observed.

Example 8 After the above materials were mixed well in a blender, they were kneaded with a biaxial kneading extruder set at 150 ° C. The obtained kneaded material was cooled, coarsely pulverized by a cutter mill, and the obtained finely pulverized powder was classified by a fixed wall type air classifier to purify the classified powder.

Further, the obtained classified powder is strictly classified and removed simultaneously with a multi-segment classification device (Elbow Jet Classifier manufactured by Nittetsu Mining Co., Ltd.) utilizing the Coanda effect to simultaneously remove ultrafine powder and coarse powder, thereby obtaining a volume average particle diameter of 11.3 μm. A fine blue powder (that is, toner particles) was obtained.

On the other hand, silica fine powder Aerosil 200 (manufactured by Nippon Aerosil Co., Ltd.) was treated with the silane coupling agent shown in Compound Example (4-1) (at a temperature of 150 ° C. for 2 hours) to obtain a silica fine powder of the present invention. I got a body.

0.4% of this silica fine powder was externally added to the above blue fine powder to obtain a toner.

Next, a copy test of this toner was performed using a commercially available copying machine NP-6650 (manufactured by Canon Inc.).

The image obtained under the environment of 23 ° C and 60% R / H has a density of 1.36.
It was clear enough and high. Further, the uniformity of density of the solid image was also excellent. In addition, 15 ℃, 10% R / H and 30 ℃, 85% R
Although images were obtained under the environment of / H, the image density was 1.33 and 1.37, respectively, and no image density fluctuations due to environmental changes were observed. Also,
The image quality such as the density uniformity of the solid image did not change due to the environmental change.

[Effects of the Invention] As described above, the silica according to the present invention undergoes environmental fluctuations so as to properly compensate for the triboelectric charge of the toner without silica.

For this reason, the negatively chargeable electrostatic image developing toner to which silica is externally added according to the present invention can provide an image with excellent image quality without any fluctuation in image quality due to environmental changes.

In particular, when the toner is adapted to a color toner, the halftone image does not fluctuate in the environment, so that an excellent full-color image can be always provided under any environment.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-298354 (JP, A) JP-A-64-33560 (JP, A) JP-A-2-217863 (JP, A) JP-A 63-29863 46469 (JP, A) JP-A-2-66558 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 9/08 CA (STN)

Claims (7)

(57) [Claims] 1. A toner particle comprising at least a colorant and a binder resin, comprising: (i) a positive triboelectrification site selected from the group consisting of an amino group, a nitrogen-containing heterocyclic group and a phosphorus-containing organo group; A negatively-chargeable electrostatic image developing toner, comprising externally added a negatively-chargeable silica fine powder treated with a silane coupling agent having a negatively-chargeable site. 2. The negatively chargeable electrostatic image developing toner according to claim 1, wherein the negatively triboelectrically charged portion of the silane coupling agent is caused by a Si—C bond. 3. The toner for developing a negatively chargeable electrostatic image according to claim 1, wherein the negatively triboelectrically chargeable portion of the silane coupling agent is caused by an organic acid. 4. The negatively chargeable electrostatic image developing toner according to claim 1, wherein the negatively triboelectrically chargeable portion of the silane coupling agent is caused by a halogen atom. 5. The negatively chargeable electrostatic image developing toner according to claim 1, wherein the negatively triboelectrically charged portion of the silane coupling agent is caused by a carbonyl group. 6. The toner for developing a negatively chargeable electrostatic image according to claim 1, wherein the negatively triboelectrically chargeable portion of the silane coupling agent is caused by a hydroxyphenyl group. 7. The silane coupling agent according to claim 1, wherein the negatively triboelectrically charging site is attributable to a cyano group.
The toner for developing a negatively chargeable electrostatic image as described in the above item.