JP2704027B2 - Negative triboelectric toner for electrostatic image development - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner for developing an electrostatic latent image in an image forming method such as electrophotography and electrostatic recording.

[Conventional technology]

Conventionally, as electrophotography, U.S. Patent 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 finely pulverizing a dispersion of a colorant in a binder resin such as polystyrene to about 1 to 30 μm are used as the 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 mixing 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 fog, external addition of silica fine powder has been widely performed to impart fluidity to toner.

However, although the above problem is improved by external addition of silica, 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, the improvement 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.

[Problems to be solved by the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a negatively triboelectric toner for developing an electrostatic image which is externally added with a novel silica fine powder which solves the above-mentioned problems.

That is, an object of the present invention is to improve the image characteristics by externally added silica fine powder, and to remarkably reduce the environmental fluctuation of the image, and to obtain an electrostatic charge capable of obtaining an image with excellent image quality under any environment. An object of the present invention is to provide a negative frictionally chargeable toner for image development.

Another object of the present invention is to provide a negative frictionally chargeable toner for developing an electrostatic image, which exhibits good charging characteristics and can obtain an image with less fogging.

Still another object of the present invention is to easily and surely positively charge the positive triboelectrically charging silane coupling agent, and to set the triboelectric charging amount of the silica fine powder together with the negative triboelectric charging silane coupling agent within a predetermined range. It is another object of the present invention to provide a negatively triboelectric charging toner for developing an electrostatic image, which can obtain a good image by adjusting the image quality.

Still another object of the present invention is to provide a negative triboelectrically-chargeable silane coupling agent capable of sufficiently effectively negatively triboelectrically charging the silica fine powder together with the positive frictional silane coupling agent within a predetermined range. It is another object of the present invention to provide a negatively triboelectric charging toner for developing an electrostatic image, which can obtain a good image by adjusting the image quality.

Still another object of the present invention is to easily and surely negatively charge the negative frictionally chargeable silane coupling agent, and to set the frictional charge amount of the silica fine powder together with the positive frictionally chargeable silane coupling agent within a predetermined range. It is an object of the present invention to provide a negatively triboelectric charging toner for developing an electrostatic image which can be adjusted to obtain a good image.

[Means and actions for solving the problem]

The present invention is a toner in which silica fine powder is externally added to negative frictionally chargeable toner particles having at least a colorant and a binder resin, wherein the silica fine powder is a positive frictionally chargeable silane coupling agent, It is a silica fine powder treated with both a negative triboelectrically charging silane coupling agent and exhibits a triboelectric charging characteristic of 0 μC / g in a low-temperature and low-humidity environment at a temperature of 15 ° C. and a humidity of 10% RH. It has a positive triboelectric charging property of greater than or equal to +50 μC / g, and a negative triboelectric charging property in the range of −10 to −150 μC / g in a high-temperature and high-humidity environment at a temperature of 35 ° C. and a humidity of 85% RH. The present invention relates to a negative frictionally chargeable toner for developing an electrostatic charge image, which is a silica fine powder.

Further, the present invention is the negative frictionally chargeable toner for developing an electrostatic image, wherein the positive frictionally chargeable silane coupling agent has a nitrogen-containing organo group.

Further, the present invention is the negatively triboelectrically charging toner for developing an electrostatic image, wherein the positively triboelectrically charging silane coupling agent has a phosphorus-containing organo group.

Furthermore, the present invention is the negative frictionally chargeable toner for developing an electrostatic image, wherein the negative frictionally chargeable silane coupling agent has an alkyl group or a phenyl group having 7 or less carbon atoms.

Still further, the present invention provides the negative frictionally chargeable toner for developing an electrostatic image, wherein the negative frictionally chargeable silane coupling agent has an organic acid.

Still further, the present invention provides the negative frictionally chargeable toner for developing an electrostatic image, wherein the negative frictionally chargeable silane coupling agent has a halogen atom.

Still further, the present invention is the negative frictionally chargeable toner for developing an electrostatic image, wherein the negative frictionally chargeable silane coupling agent has a carbonyl group.

Furthermore, the present invention is a negative frictionally chargeable toner for developing an electrostatic image, wherein the negative frictionally chargeable silane coupling agent has a phenol derivative.

Furthermore, the present invention is a negative frictionally chargeable toner for developing an electrostatic image, wherein the negative frictionally chargeable silane coupling agent has a cyano group.

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. As such an example, Japanese Patent Laid-Open Publication No.
Japanese Patent Publication No. 42354/1992 and Japanese Patent Publication No. Sho 54-16219 discloses a method of externally adding hydrophobic silica to a toner. Also,
JP-A-56-123550 discloses external addition of silica treated with a silane coupling agent to a toner.
Thus, previous developments focused solely on treating agents and treatments for hydrophobizing silica.

The present inventors have confirmed that the greatest cause of environmental instability of the toner is environmental fluctuation of the triboelectric charge amount of the toner.
In addition, it has been found that even if the toner is not silica-externally added, the amount of triboelectric charge changes due to environmental fluctuations, and the external addition of silica further increases this. The degree of environmental fluctuation of the triboelectric charge amount of the toner varies depending on the type of toner carrier such as a carrier or a sleeve, but silica has the most influence.

In addition, the amount of triboelectricity of silica-externally added toner varies depending on the environment. Therefore, in order to eliminate the environmental dependence of the triboelectricity of the toner, it is not sufficient for the triboelectricity of silica itself to be free from environmental fluctuations. Therefore, it is necessary to change so as to cancel the change of the toner not having silica externally added. Moreover, the use of silica having a low triboelectric charge amount is advantageous in that the amount of triboelectric charge of the toner can be reduced because the amount of triboelectric charge of the toner can be kept low. As a result of intensive studies, the present inventors have found that silica preferably has a lower negative triboelectric charging property at lower humidity, and more preferably has a positive triboelectric charging property of almost 0 μC / g or rather weak positive triboelectric charging property. The triboelectric charge amount here is a value measured by a blow-off method after shaking for 20 seconds with a turbula mixer at a ratio of silica and carrier of 2: 100. The fine silica powder used in the present invention has a triboelectric charge amount in a low humidity range (temperature 15 ° C./humidity 10% RH) of 0 to +50 μC / g, and a triboelectric charge characteristic of 0 μC / g in a low humidity environment. Or exhibit a positive triboelectric charging property of greater than 0 to +50 μC / g,
Thereby, generation of fog is suppressed. On the other hand, the silica fine powder used in the present invention is used under high humidity (temperature 35 ° C./humidity 85
% RH), exhibiting a negative triboelectric chargeability of -10 to -150 µC / g (more preferably -30 to -100 µC / g). The triboelectric charge amount in the present invention is measured by the above-described method, and is a value when a carrier actually used in a copying machine is used. In the case of a one-component toner, it is the triboelectric charge amount measured using a carrier that matches the sleeve material of the developing base. However, for uncoated metal sleeves,
The value of the triboelectric charge amount measured using an iron powder carrier may be used instead. Therefore, the appropriate silica varies depending on the type of the carrier used.

The present inventors have newly found the above findings and have developed a novel silica.

As a result of intensive studies, both the positive triboelectric charging silane coupling agent and the negative triboelectric charging silane coupling agent were used in combination,
Furthermore, if the combination of the positive triboelectric silane coupling agent and the negative triboelectric silane coupling agent becomes lower in humidity than the negative triboelectric charging silane coupling agent, the rate of increase in the absolute value of the triboelectric charge becomes larger, the high temperature and high humidity environment Below -10 to -150
It shows a negative triboelectric charge of μC / g, and a low triboelectric charge of 0 μC / g to a weak positive triboelectric charge (ie, +5
(0 μC / g or less), thereby completing the present invention.

As the silica fine powder of the silica fine powder of the present invention before being treated with the silane coupling agent, either dry silica or wet silica can be used. Silica is 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 manufacturing process, for example, by using another metal halide derivative such as aluminum chloride or titanium chloride together with a silicon halide derivative, a composite fine powder of silica and another metal oxide is obtained. It is also possible to obtain, and these are also contained.

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 by an acid, if shown 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 + HaCl In addition, ammonia salts of sodium silicate or alkali 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, etc. 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. It is also preferable to use several kinds of silica fine powders having different specific surface areas from the viewpoint of imparting fluidity.

Examples of the positive frictionally charging silane coupling agent include a coupling agent having an organic group such as an amino group or 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 dehydrogenated compounds of the following compounds.

Examples of the saturated heterocyclic group include dehydrogenated compounds of the following compounds.

Also, nitrogen-containing salt compounds such as quaternary ammonium salts and pyridinium salts can be exemplified. Further, phosphine, phosphonium salt and the like can be exemplified. However, ease of synthesis,
Considering the price, an amino group and a nitrogen-containing bicyclic group are preferred.

Various examples of the negative frictionally chargeable silane coupling agent can be given.

For example, conventional silane coupling agents having no organic groups containing nitrogen or phosphorus are negatively triboelectrically chargeable.
This is thought to be due to the Si-C bond, but such a thin-lank coupling agent is very preferable in view of the ease of synthesis. In this case, however, the negative triboelectric charging property due to the Si—C bond decreases with an increase in the number of carbon atoms of the hydrocarbon directly bonded to Si.
These cannot be used because they do not exhibit sufficiently effective negative triboelectricity. Preferably, it has 5 or less carbon atoms.

Further, an organic acid such as a carboxylic acid or a sulfonic acid or a derivative thereof, or a silane coupling agent having an acidic hydroxy group-containing organic group such as phenol is also preferable.

Further, a silane coupling agent having an organic group containing a halogen atom, a carbonyl group, a sulfonyl group, a cyano group, or the like can also be used effectively.

One of the features of the present invention is that silica is obtained by a combination of the above-described positive triboelectric charging silane coupling agent and negative triboelectric charging silane coupling agent. In addition, it is necessary to combine the positive triboelectrically charging silane coupling agent so that the rate of increase in the triboelectric charging amount under low humidity is higher than that of the negative triboelectrically charging silane coupling agent.

In order to obtain the silica fine powder of the present invention, either of the positive and negative silane coupling agents may be treated first, but in consideration of the uniformity of the treatment, a mixture of the positive and negative silane coupling agents in advance is used. Preferably, the silica is treated.

In addition, since the treatment amount ratio of the positive frictionally chargeable silane coupling agent to the negative frictionally chargeable silane coupling agent varies depending on the type of the treatment agent used or the intended triboelectric charge amount of silica, it cannot be determined uniquely. . However, considering the ease of processing and the uniformity of the processing, it is preferable that the processing amounts of the positive and negative silane coupling agents do not greatly differ between the two, and the processing amount ratio falls within the range of 1/20 to 20/1. Is preferred.

In the present invention, typical examples of the silane coupling agent are shown below, but these do not limit the present invention in any way.

1-1) Silane coupling agent having negative triboelectrification by having an alkyl group or phenyl group having 7 or less carbon atoms 1-2) Silane coupling agent having negative triboelectric charge due to halogen, carbonyl, phenol, cyano group, etc. 1-3) Silane coupling agent having negative triboelectric charge due to organic acid or derivative thereof 2-1) Silane coupling agent having positive triboelectric charging property by amino group 2-2) Silane coupling agent having positive triboelectric charging property by nitrogen-containing heterocycle 2-3) Silane Coupling Agent Having Positive Triboelectric Charging Property Due to Quaternary Ammonium Salt 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 in combination with each other or some known silicas.

On the other hand, the resin for forming the toner particles used in the present invention includes, for example, homopolymers of styrene such as polystyrene, poly-p-chlorostyrene, and polyvinyltoluene and substituted products thereof; styrene-p-chlorostyrene. 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-isoprene copolymer, styrene- Acrylonitrile
Styrene copolymers such as indene copolymers; polyvinyl chloride, phenolic resin, natural modified phenolic resin, natural resin modified maleic resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane, polyamide Resin, furan resin,
Epoxy resin, xylene resin, polyvinyl butyral,
Terpene resins, coumarone 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 acid. Monocarboxylic acid having a double bond such as acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide or a substitute thereof; for example, maleic acid, butyl maleenate , Dicarboxylic acids having a double bond such as methyl maleate, dimethyl maleate and the like and substituted products thereof; for example, vinyl esters such as vinyl chloride, vinyl acetate and vinyl benzoate; for example, ethylene, propylene, Vinyl monomers such as ethylene-based olefins such as ethylene; 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; Are used alone or in combination of two or more. As the crosslinking agent, a derivative having two or more polymerizable double bonds is mainly used, for example, an aromatic divinyl derivative such as divinylbenzene, divinylnaphthalene or the like; for example, ethylene glycol diacrylate, ethylene glycol diacrylate, or the like. Methacrylate, 1,
Carboxylic acid esters having two double bonds such as 3-butanediol dimethacrylate; divinyl derivatives such as divinylaniline, divinylether, divinylsulfide and divinylsulfone; and derivatives 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 salicylic acid derivative complex, a monoazo derivative complex, 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, the triboelectricity of the binder resin can be utilized without using the charge control agent.

Examples of the coloring agent used in the present invention include carbon black, lamp black, iron black, ultramarine blue, nigrosine dye, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa Yellow G, rhodamine 6G, coco 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 in a mixture with a carrier. As the carrier that can be used in the present invention, known materials can be used, for example, iron powder, ferrite powder, magnetic powder of nickel powder, glass beads, and the like, and those obtained by treating the surfaces thereof with a resin or the like. Is raised. Examples of the resin for coating the carrier surface include styrene-acrylate copolymer, styrene-methacrylate copolymer, acrylate copolymer, methacrylate copolymer, silicone resin, and fluorine-containing resin. , A polyamide resin, an ionomer resin, a polyphenylene sulfide resin or the like, or a mixture thereof.

Further, the negative frictionally chargeable toner for developing an electrostatic image of the present invention can be used as a magnetic toner by containing a magnetic material. The magnetic materials used include magnetite, γ
Iron oxides such as iron oxides, ferrites and iron-rich ferrites; metals such as iron, cobalt, nickel or these metals and aluminum, cobalt, copper, lead, magnesium,
Examples include alloys with metals such as tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, and vanadium, and mixtures thereof. These magnetic materials have an average particle size of 0.
It is preferably about 1 to 1 μm, preferably about 0.1 to 0.5 μm, and the amount contained in the magnetic toner is 40 to 150 parts by weight, preferably 60 to 12 parts by weight, per 100 parts by weight of the binder resin component.
0 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.

Further, fluorine-containing polymer fine powder such as polyvinylidene fluoride fine powder and methyl methacrylate resin powder are also preferable additives from the viewpoints of fluidity, abrasiveness, charge stability and the like.

In addition, wax-like substances such as low-molecular-weight polyethylene, low-molecular-weight polypropylene, microcrystalline wax, carnauba wax, sasol wax, and paraffin wax are used for the purpose of improving the releasability at the time of hot roll fixing.
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 such as a hot roll kneader or an extruder, and cooled into individual pieces. Thereafter, a method of obtaining a toner by mechanical pulverization and classification is preferable. Alternatively, a method of dispersing a constituent material in a binder resin solution and then spray-drying to obtain the toner; or a method of forming the binder resin A polymerization method for producing a toner by mixing a predetermined material with a monomer to be obtained to form an emulsified suspension and then polymerizing 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, can be applied. Further, if necessary, the desired additives can be sufficiently mixed by a mixer such as a Hensiel 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.

 Hereinafter, the measuring method of the present invention will be described.

(1) Measurement of triboelectric charge: The measurement method will be described in detail with reference to the drawings.

FIG. 1 is an explanatory view of an apparatus for measuring a triboelectric charge amount of toner and silica. First, a mixture of a toner and a carrier in a weight ratio of 1:19 or a mixture of silica in a ratio of 2: 100 in a metal measuring container 2 having a screen 3 with a 500 mesh at the bottom is to be measured. Into a 50-100 ml polyethylene bottle, shake by hand for about 20 seconds (arbitrarily measure between about 10-40 seconds), add about 0.5-1.5 g of the mixture (developer), and place Cover 4. At this time, the weight of the entire measurement container 2 is weighed and defined as W ₁ (g). Next, in the suction device 1 (at least the portion in contact with the measurement container 2 is at least an insulator), the suction is performed through the suction port 7 and the air volume control valve 6 is adjusted to adjust the pressure of the vacuum gauge 5 to 250 mmAq. In this state, suction is sufficiently performed, preferably for 2 minutes, to remove the toner by suction. The potential of the electrometer 9 at this time is set to V (volt).
Here, reference numeral 8 denotes a capacitor, whose capacity is C (μF). Further, the weight of the whole measurement container after suction is weighed to be W ₂ (g). The triboelectric charge (μc / g) of this toner is calculated as in the following equation.

(However, the measurement conditions are a temperature of 23 ° C. and a humidity of 60% RH.) The carrier used for the measurement is an acrylic resin-coated ferrite carrier having 250 to 350% by weight of carrier particles of 350 mesh.

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 is cooled, coarsely pulverized by a cutter mill, finely pulverized using a fine pulverizer using a jet stream, and the obtained finely pulverized powder is classified and colored by a fixed wall type air classifier. Fine powder (not externally added toner) was obtained.

Further, the obtained classified powder is strictly classified and removed at the same time by a multi-division classifier utilizing a Coanda effect (Elbojet Classifier manufactured by Nippon Steel Mining Co., Ltd.) to remove cyan powder having a volume average particle diameter of 8.3 μm. Particles were obtained.

On the other hand, a silane coupling agent shown in Compound Example (1-2-1) and a silane coupling agent shown in Compound Example (2-2-1) were added to silica fine powder Aerosil 200 (manufactured by Nippon Aerosil Co., Ltd.). Was treated at a mixing ratio of 15/5 (temperature: 150 ° C., time: 2 hours, treated amount: 100 g of silica, 20 g of silane coupling agent) to obtain a silica fine powder of the present invention.

0.5% of this silica fine powder in the above-mentioned cyan toner particles
Externally added, a toner was obtained.

Acrylic coated ferrite carrier with an average particle size of 45 μm
5 parts of the obtained toner was mixed with 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 in an environment of a temperature of 23 ° C. and a humidity of 60% RH (N / N) had a sufficiently high density of 1.63 and was sharp. In addition, the solid image was excellent in density uniformity and reproducibility of a halftone image. In addition, images were obtained in an environment with a temperature of 15 ° C / humidity 10% RH (L / L) and a temperature of 30 ° C / humidity 85% RH (H / H). No concentration fluctuation was observed. Also, the image quality such as the density uniformity of the solid image and the reproducibility of the halftone image hardly fluctuated due to the environmental change.

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

Example 2 5 parts of the copper phthalocyanine pigment in Example 1 was replaced with (CI
Pigment Yellow 17) Yellow toner particles were obtained in the same manner as in Example 1 except that the amount was changed to 3.5 parts.

0.5% of the same silica fine powder as in Example 1 was externally added to the above-mentioned yellow toner particles to obtain a toner.

Acrylic coated ferrite carrier 10 with an average particle size of 45 μm
5 parts of the obtained toner was mixed with respect to 0 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 in an environment with a temperature of 23 ° C. and a humidity of 60% RH (N / N) had a sufficiently high density of 1.58 and was sharp. In addition, the solid image was excellent in density uniformity and reproducibility of a halftone image. In addition, images were obtained in an environment with a temperature of 15 ° C / humidity 10% RH (L / L) and a temperature of 30 ° C / humidity 85% RH (H / H). No concentration fluctuation was observed. Also, the image quality such as the density uniformity of the solid image and the reproducibility of the halftone image hardly fluctuated due to the environmental change.

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

Example 3 Magenta toner particles were obtained in the same manner as in Example 1, except that 5 parts of the copper phthalocyanine pigment in Example 1 was changed to 1 part of a quinacridone-based pigment (CI Pigment Red 122).

0.5% of the silica fine powder used in Example 1 was externally added to the above magenta toner particles to obtain a toner.

Acrylic coated ferrite carrier with an average particle size of 45 μm
5 parts of the obtained toner was mixed with 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 in an environment of a temperature of 23 ° C. and a humidity of 60% RH (N / N) had a sufficiently high density of 1.62 and was sharp. In addition, the solid image was excellent in density uniformity and reproducibility of a halftone image. In addition, images were obtained in an environment with a temperature of 15 ° C / humidity 10% RH (L / L) and a temperature of 30 ° C / humidity 85% RH (H / H). No concentration fluctuation was observed. Also, the image quality such as the density uniformity of the solid image and the reproducibility of the halftone image hardly fluctuated due to the environmental change.

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

Example 4 Black toner particles were obtained in the same manner as in Example 1 except that 5 parts of the copper phthalocyanine pigment in Example 1 was changed to 5 parts of carbon black.

0.5% of the silica fine powder used in Example 1 was externally added to the above black toner particles to obtain a toner.

Acrylic coated ferrite carrier with an average particle size of 45 μm
5 parts of the obtained toner was mixed with 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 in an environment of a temperature of 23 ° C. and a humidity of 60% RH (N / N) had a sufficiently high density of 1.67 and was sharp. In addition, the solid image was excellent in density uniformity and reproducibility of a halftone image. In addition, images were obtained in an environment with a temperature of 15 ° C / humidity 10% RH (L / L) and a temperature of 30 ° C / humidity 85% RH (H / H). No concentration fluctuation was observed. Also, the image quality such as the density uniformity of the solid image and the reproducibility of the halftone image hardly fluctuated due to the environmental change.

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

1.62 concentration in an environment of 23 ° C / 60% RH (N / N)
A good image with a temperature of 30 ° C / 85% RH (N /
The image density increased to 1.70 under the environment of N), and decreased to 1.27 under the environment of the temperature of 15 ° C. and the humidity of 10% RH (L / L). This is due to the fact that the amount of triboelectric charge has increased as shown in Table 1.

Comparative Example 2 0.5% of the silica fine powder used in Example 1 was treated with diethylaminopropyltrimethoxysilane to obtain a triboelectric charge of 23 ° C / 60% RH (N / N) and 15 ° C / 10% RH (L).
/ L), a temperature of 30 ° C and a humidity of 85% RH (N / N). Toner was obtained and copied in the same manner as in Example 1 except that the silica fine powder was changed to +140, +130, and +60 to 0.5%, respectively. Tested.

In particular, the toner was scattered severely under high temperature and high humidity and could not be put to practical use. In addition, each environment had a lot of fog, resulting in an unclear image.

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 by using a fine pulverizer using a jet stream, and the obtained finely pulverized powder was classified by a fixed wall type air classifier to classify. The powder was purified.

Further, the obtained fine powder is strictly classified and removed simultaneously by a multi-division classifier utilizing a Coanda effect (an elbow jet classifier manufactured by Nippon Steel Mining Co., Ltd.) to obtain a black toner having a volume average particle diameter of 11.8 μm. Particles were obtained.

On the other hand, a silane coupling agent shown in Compound Example (1-1-4) and a silane coupling agent shown in Compound Example (2-1-6) were added to silica fine powder Aerosil 200 (manufactured by Nippon Aerosil Co., Ltd.). At a mixing ratio of 19/1 (temperature: 150 ° C., time: 2 hours, treatment amount: 100 g of silica, 20 g of silane coupling agent) to obtain a silica fine powder of the present invention.

This silica fine powder is added to the above black toner particles by 0.4
% Externally added 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 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 in an environment of a temperature of 23 ° C. and a humidity of 60% RH (N / N) had a sufficiently high density of 1.56 and was sharp. In addition, the solid image was excellent in density uniformity and reproducibility of a halftone image. In addition, images were obtained in an environment with a temperature of 15 ° C / humidity 10% RH (L / L) and a temperature of 30 ° C / humidity 85% RH (H / H). No concentration fluctuation was observed. Also, the image quality such as the density uniformity of the solid image and the reproducibility of the halftone image hardly fluctuated 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 by using a fine pulverizer using a jet stream, and the obtained finely pulverized powder was classified by a fixed wall type air classifier to classify. The powder was purified.

Further, the obtained classified powder is strictly classified and removed at the same time by a multi-division classifier utilizing a Coanda effect (an elbow jet classifier manufactured by Nippon Mining Co., Ltd.) to remove magnetic powder having a volume average particle size of 8.1 μm. Particles were obtained.

On the other hand, the silica silane coupling agent shown in Compound Example (1-1-1) and the silane coupling agent shown in Compound Example (2-1-1) were added to silica fine powder Aerosil 300 (manufactured by Nippon Aerosil Co., Ltd.). Was treated at a mixing ratio of 15/5 (temperature: 150 ° C., time: 2 hours, treated amount: 100 g of silica, 20 g of silane coupling agent) to obtain a silica fine powder of the present invention.

0.6% of this silica fine powder was externally added to the above magnetic toner particles 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 in an environment with a temperature of 23 ° C. and a humidity of 60% RH (N / N) had a sufficiently high density of 1.41 and was sharp. Further, the uniformity of density of the solid image was also excellent. In addition, the temperature 15 ℃
Humidity 10% RH (L / L) and temperature 30 ° C / humidity 85% RH (H / H)
Although the image was obtained under the same environment, the image density was 1.43 and 1.38, respectively. In addition, the image quality such as the density uniformity of the solid image hardly changed due to the environmental change.

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 subjected to strict classification and removal of ultrafine powder and coarse powder at the same time by a multi-segment classification device (Elbojet classifier manufactured by Nittetsu Mining Co., Ltd.) utilizing the Coanda effect, and cyan toner having a volume average particle diameter of 10.3 μm. Particles were obtained.

On the other hand, a silane coupling agent shown in Compound Example (1-1-7) and a silane coupling agent shown in Compound Example (2-2-4) were added to silica fine powder Aerosil 300 (manufactured by Nippon Aerosil Co., Ltd.). Was treated at a mixing ratio of 10/10 (temperature: 150 ° C., time: 2 hours, treatment amount: 100 g of silica, 20 g of silane coupling agent) to obtain silica fine powder of the present invention.

0.4% of this silica fine powder in the above-mentioned cyan toner particles
Externally added, a toner was obtained.

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

The image obtained in an environment of a temperature of 23 ° C. and a humidity of 60% RH (N / N) had a sufficiently high density of 1.37 and was sharp. Further, the uniformity of density of the solid image was also excellent. In addition, the temperature 15 ℃ /
Humidity 10% RH (L / L) and temperature 30 ° C / humidity 85% RH (H / H)
Although the image was obtained under the environment of 1.39, 1.39 and 1.30, respectively, almost no change in the image density due to the environmental change was observed.
Also, no significant change in the image quality such as the uniformity of the density of the solid image due to the environmental change was observed.

〔The invention's effect〕

The negative frictionally chargeable toner for electrostatic image development of the present invention is a toner in which silica fine powder is externally added to negative frictionally chargeable fine powder particles having at least a colorant and a binder resin,
The silica fine powder is treated with both a positive triboelectrically charging silane coupling agent and a negative triboelectrically charging silane coupling agent. Since it is characterized by being a body, image characteristics can be improved by externally added silica fine powder, and environmental fluctuation of the image can be significantly reduced, and an image of excellent image quality can be obtained under any environment. Can also be obtained.

Further, the negative frictionally chargeable toner for developing an electrostatic image of the present invention,
The triboelectric charge amount of the silica fine powder is 15 ° C in temperature and 10% in humidity.
Since it is within a range of −30 to +100 μC / g in an environment of RH, an image showing good charging characteristics and less fogging can be obtained.

Further, the negative frictionally chargeable toner for developing an electrostatic image of the present invention is characterized in that the positive frictionally chargeable silane coupling agent has a nitrogen-containing organo group or a phosphorus-containing organo group. The ring agent is easily and surely positively triboelectrically charged, and the triboelectric charge amount of the silica fine powder together with the negatively triboelectrically chargeable silane coupling agent is adjusted within a predetermined range, whereby a good image can be obtained.

Further, the negative frictionally chargeable toner for developing an electrostatic image of the present invention is characterized in that the negative frictionally chargeable silane coupling agent has an alkyl group having 7 or less carbon atoms.
The negatively triboelectric silane coupling agent can be negatively triboelectrically charged sufficiently effectively, and together with the positive tribosilane coupling agent, the triboelectric charge amount of the silica fine powder can be adjusted within a predetermined range to obtain a good image. it can.

Furthermore, the negative frictionally chargeable toner for developing an electrostatic image of the present invention is characterized in that the negative frictionally chargeable silane coupling agent has an organic acid, a halogen atom, a carbonyl group, a phenol derivative or a cyano group. The negatively triboelectrically-chargeable silane coupling agent is easily and reliably negatively triboelectrically charged, and the triboelectric charge amount of the silica fine powder together with the positively triboelectrically-chargeable silane coupling agent is adjusted to be within a predetermined range. Images can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory view of an apparatus for measuring a triboelectric charge amount of toner and silica in a triboelectric charge amount measurement. DESCRIPTION OF SYMBOLS 1 ... Suction machine 2 ... Measuring container 3 ... Conductive screen 4 ... Lid 5 ... Vacuum gauge 6 ... Air flow control valve 7 ... Suction port 8 ... Condenser 9 ... Electrometer

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-66558 (JP, A) JP-A-64-33560 (JP, A) JP-A-62-129862 (JP, A) JP-A-2- 83551 (JP, A) JP-A-1-219760 (JP, A)

Claims (10)

(57) [Claims] Claims: 1. A toner in which silica fine powder is externally added to negative friction charge toner particles having at least a colorant and a binder resin, wherein the silica fine powder comprises a positive friction charge silane coupling agent. , A silica fine powder treated with both a negative triboelectrically charging silane coupling agent and exhibiting a triboelectric charging characteristic of 0 μC / g in a low-temperature and low-humidity environment at a temperature of 15 ° C. and a humidity of 10% RH, or It has a positive triboelectric charging characteristic of greater than 0 to +50 μC / g, and a negative triboelectric charging characteristic of −10 to −150 μC / g in a high-temperature and high-humidity environment at a temperature of 35 ° C. and a humidity of 85% RH. Triboelectrically-chargeable toner for developing electrostatic images, characterized in that the toner is silica fine powder having the same. 2. The negatively triboelectrically chargeable toner for developing an electrostatic image according to claim 1, wherein the positively triboelectrically chargeable silane coupling agent has a nitrogen-containing organo group. 3. The negative frictionally chargeable toner for developing electrostatic images according to claim 1, wherein the positive frictionally chargeable silane coupling agent has a phosphorus-containing organo group. 4. The negative charge for developing an electrostatic image according to claim 1, wherein the negative frictionally chargeable silane coupling agent has an alkyl group or a phenyl group having 7 or less carbon atoms. Triboelectric charging toner. 5. The negative frictionally chargeable toner for developing an electrostatic image according to claim 1, wherein the negative frictionally chargeable silane coupling agent has an organic acid or a derivative thereof. 6. The negative frictionally chargeable toner for developing an electrostatic image according to claim 1, wherein the negative frictionally chargeable silane coupling agent has a halogen atom. 7. The negative frictionally chargeable toner for developing an electrostatic image according to claim 1, wherein the negative frictionally chargeable silane coupling agent has a carbonyl group. 8. The method according to claim 1, wherein the negative frictionally chargeable silane coupling agent has a phenol derivative.
Or the negative frictionally chargeable toner for developing an electrostatic image according to (2). 9. The negative frictionally chargeable toner for developing an electrostatic image according to claim 1, wherein the negative frictionally chargeable silane coupling agent has a cyano group. 10. The fine silica powder has a temperature of 35 ° C. and a humidity of 85% RH.
The toner according to any one of claims 1 to 9, wherein the toner has a triboelectric charge of -30 to -100 µC / g in a high-temperature and high-humidity environment. .