JPH03105356A - Positive chargeable toner for developing electrostatic charge image - Google Patents

Abstract

PURPOSE:To obtain the positive chargeable toner for developing electrostatic charge images with which images having high image quality are obtained stably over a long period of by adding fine powder of positive chargeable silica onto fine powder particles consisting of the pyridinium compd. expressed by specific formula, a coloring agent and a binder resin. CONSTITUTION:The fine powder of the positive chargeable silica is added onto the colored powder formed by using the p-aminopyridinium copd. expressed by the formula as a charge control agent. In the formula, R1, R2 are H, alkyl group; R1, R2 may form a ring; R3 is an alkyl group, aryl group, aralkyl group, cyclic aralkyl group; X<-> is an anion, such as org. sulfonic acid ion, org. sulfuric acid ion, org. carboxylic acid ion, org. boric acid ion, polyacid ion, heteropolyacid ion, tetrafluoroborate ion, or hexafluorophosphate ion. The fine powder of the silica which is treated with a silane compd. RmSiYn or treated with an Si oil having an organo group or amino group having N in the side chain is used. R is alkoxy or halogen; m=1 to 3; Y is an amino group or organo group having 1 N; 1<n<3 and m+n=4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a toner for visualizing electrostatic latent images in image forming methods such as electrophotography and electrostatic recording.

[Prior Art] Conventionally, as an electrophotographic method, US Patent No. 2. 29769
1, Special Publication No. 42-23910, and Special Publication No. 4
Various methods are described in Japanese Patent No. 3-24748 and the like.

The developing methods applied to these electrophotographic methods include:
Broadly speaking, there are dry development methods and wet development methods. The former method is further divided into methods using a two-component developer and methods using a one-component developer.

As toners applied to these dry development methods, fine powders in which dyes and pigments are dispersed in natural or synthetic resins have conventionally been used. For example, particles obtained by dispersing a colorant in a binder resin such as polystyrene and pulverizing the particles to about 1 to 30 pm are used as the toner. As the magnetic toner, those containing magnetic particles such as Magnetite 1 are used. Furthermore, in the case of a system using a two-component type developer, the toner is usually mixed with carrier particles such as glass beads and iron powder.

Either toner must have a positive or negative charge depending on the polarity of the electrostatic latent image being developed.

In order to make the toner hold an electric charge, it is also possible to use the triboelectricity of the resin that is a component of the toner, but since the toner's chargeability is low with this method, the image obtained by development is prone to fogging and is unclear. Become something.

Therefore, in order to impart appropriate triboelectricity to the toner,
Dyes, pigments, and even charge control agents that impart chargeability are added.

Charge control agents known in the technical field today include nigrosine dyes, azine dyes, triphenylmethane dyes, quaternary ammonium salts, and polymers having quaternary ammonium salts in their side chains. There is.

[Problems to be Solved by the Invention] However, since some of these charge control agents tend to contaminate the sleeve or carrier, the amount of triboelectric charge of toners using them decreases as the number of copies increases. , causing a decrease in image density.

Furthermore, some charge control agents have insufficient triboelectric charge and are susceptible to in-4 degrees, which causes environmental fluctuations in image density. In addition, certain charge control agents are
Storage stability is poor, and triboelectric charging ability decreases during long-term storage. Furthermore, since some charge control agents have poor dispersibility in resins, toners using these agents tend to have non-uniform triboelectric charges between particles and are prone to fogging. Additionally, some charge control agents are colored and cannot be used in color toners.

At present, there is a strong demand for the development of a charge control agent that satisfies all of these requirements.

[Means and effects for solving the problems] The present invention provides a toner in which a positively chargeable silica fine powder is externally added to a colored fine powder using a p-aminoviridinium compound as a charge control agent, which solves the above-mentioned problems. It provides:

The p-aminopyridinium compound has higher positive triboelectric chargeability than conventional viridinium compounds and can be made lighter in color, so it can also be used as a charge control agent for color toners. However, as a result of studies conducted by the present inventors, it was found that the amount of triboelectric charge of p-aminopyridinium salt changes depending on the type of counter ion. As a result, by selecting a counter ion, it was possible to significantly improve positive triboelectric charging properties compared to conventionally known viridinium compounds. However, in order to completely solve the above problems, it is still necessary to improve the triboelectric charging properties to some extent. Furthermore, since the aminoviridinium compound contaminates toner carriers such as carriers or sleeves, if it is used as a charge control agent as it is, a toner with good image quality and durability stability cannot be obtained. As a result of extensive studies, the present inventors have found that it is most effective to have positively charged silica present on the toner surface, and that these problems can be solved without causing any major adverse effects, and the present invention has been completed. I let it happen.

The charge control agent of the present invention is characterized by less contamination of the toner carrier compared to conventionally known charge control agents. The advantage is that it can be kept low compared to agents. Therefore, it is possible to solve the problem of contamination of the toner carrier without causing new problems such as contamination of the interior of the copying machine with silica.

In this way, the present inventors discovered that positively chargeable silica fine powder is indispensable in order to take advantage of the excellent properties of a special p-aminopinodinium compound as a positive charge control agent. Thus, the present invention was completed.

The p-aminoviridinium compound used in the present invention is represented by the following general formula.

Specific examples of such compounds include the following.

(1) 1 CI2828 (8) CH30{. \／N? The inclusion of CaHl■ viridinium salt in a toner is disclosed in JP-A-63-40168 and JP-A-54-158932.
No. Publication, USP4,254,205, tJsP4,2
64,697, USP4,298,672, US
It is known as P4,304,830, etc. However, these do not mention the effect of the counter ion of the present invention. Furthermore, there is no description of the effect of positively chargeable silica, which is an important component of the present invention.

In the present invention, it is essential to use a special viridinium compound with excellent characteristics as a charge control agent for toner in combination with a positively chargeable silicate fine powder. A toner for developing a charge image cannot be obtained.

In the present invention, methods for incorporating the p-aminopyridinium derivative into the toner include a method of adding it inside the toner and a method of adding it externally. The amount of these derivatives used is
It is determined by the type of binder resin, the presence or absence of additives used as necessary, and the toner manufacturing method including the dispersion method, and is not uniquely limited, but preferably the binder resin 100 0.1 to 10 parts by weight,
More preferably, it is used in an amount of 0.1 to 5 parts by weight.

In addition, when adding externally, 0.1 to 100 parts by weight of resin
It is preferable to use parts by weight of IO, and it is particularly preferable to fix it to the surface of the 1-ner particles by a mechanical method or the like.

Furthermore, the p-aminoviridinium derivative of the present invention can also be used in combination with a conventionally known charge control agent.

In addition, as the silica fine powder constituting a component of the developer in the present invention, silica fine powder manufactured by a dry method or a wet method can be used.

The dry method mentioned here is a method for producing fine silica powder produced by vapor phase oxidation of a silicon halogen derivative. For example, it is a method that utilizes the thermal decomposition oxidation reaction of silicon tetrachloride gas in oxygen and hydrogen, and the basic reaction formula is as follows.

sicp. +2L 10Q2→SiO. +4HCj)
Furthermore, in this manufacturing process, it is also possible to obtain a composite fine powder of silica and other metal oxides by using other metal halogen derivatives such as aluminum chloride or titanium chloride together with silicon halogen derivatives, and these are also included. do.

On the other hand, various conventionally known methods can be applied to produce the silica fine powder used in the present invention by a wet method.

For example, the decomposition of sodium silicate with an acid is expressed by the -M reaction formula (the reaction formula is omitted below): NazO - XSiOz+}ICi) +820-
I Sif2・nHzO+ NaC4 Others: decomposition of sodium silicate with ammonia salts or alkali salts, method of generating alkaline earth metal silicate from sodium silicate and then decomposing with acid to produce silicic acid, sodium silicate solution There are methods such as converting it into silicic acid using an ion exchange resin, and using natural silicic acid or silicate.

The silica fine powder referred to herein can be any of anhydrous silicon dioxide (silica) and other silicates such as aluminum silicate, sodium silicate, potassium silicate, magnesium silicate, and zinc silicate.

Among the above silica fine powders, the specific surface area due to nitrogen adsorption measured by the BET method is 30 m"/g or more (especially 50 to 40 m"/g).
0 m''/g) gives good results.

As a method for obtaining positively chargeable silica fine powder, the above-mentioned untreated fine silica powder is treated with a silicone oil having an organo group having at least i nitrogen atoms in the side chain, or a nitrogen-containing silane coupling agent is used. There are two methods: one method for processing, or one method for processing both.

In the present invention, positively charged silica refers to silica that has a positive triboelectric charge relative to the iron powder carrier when measured by a blow-off method.

As the silicone oil having a nitrogen atom in the side chain used in the treatment of silica fine powder, a silicone oil having at least a partial structure represented by the following formula can be used.

(In the formula, R1 represents hydrogen, an alkyl group, an aryl group, or an alkoxy group, R2 represents an alkylene group or a phenylene group, R., R. represents hydrogen, an alkyl group, or an aryl group, and R is The above alkyl group, aryl group, alkylene group, and phenylene group (representing a nitrogen-containing heterocyclic group) may have an organo group having a nitrogen atom, or may have a substituent such as halogen within the range that does not impair chargeability. It may have.

In addition, the nitrogen-containing silane cobbling agent used in the present invention is
It generally has a structure shown by the following formula.

RmSiYn (R represents an alkoxy group or a halogen, Y represents an amino group or an organo group having at least one nitrogen atom, m and n are integers from 1 to 3, and m+n = 4.) Nitrogen atom Examples of the organo group having at least one of these include an amino group having an organic group as a substituent, a nitrogen-containing heterocyclic group, or a group having a nitrogen-containing heterocyclic group. Examples of the nitrogen-containing heterocyclic group include an unsaturated heterocyclic group and a saturated heterocyclic group, and known ones can be used. Examples of the unsaturated heterocyclic group include the following.

Examples of the saturated heterocyclic group include the following.The heterocyclic group used in the present invention is preferably a five-membered or six-membered ring in consideration of stability.

Examples of such treatment agents include aminobrobyltonomethoxysilane, aminoprobyltriethoxysilane, dimethylaminobrobyltrimethoxysilane, diethylaminobrobyltrimethoxysilane, dipropylaminobrobyltrimethoxysilane, and dibutylaminobrobyl. Trimethoxysilane, monobutylaminobrobyltrimethoxysilane Dioctylaminobutyltrimethoxysilane, dibutylaminobrobyl dimethoxysilane, dibutylaminobrobyl monomethoxysilane, dimethylaminophenyltriethoxysilane, trimethoxysilyl γ-
There are probylphenylamine, trimethoxysilyl-γ-probylbenzylamine, etc. Furthermore, as the nitrogen-containing heterocycle, those having the above-mentioned structure can be used. Examples of such derivatives include trimethoxysilyl-γ- Examples include probil biveridine, trimethoxysilyl-γ-propylmorpholine, trimethoxysilyl-γ-propylimidazole, and the like.

The applied amount of these treated silica fine powders is effective when it is 0.01 to 20% based on the weight of the developer.
Particularly preferably, it exhibits positive chargeability with excellent stability when added in an amount of 0.03 to 5%. Regarding the preferred form of addition, it is preferable that 0.1 to 3% by weight of treated silica fine powder based on the weight of the developer be attached to the surface of the toner particles.

Furthermore, the silica fine powder used in the present invention may be treated with a silane coupling agent or a treatment agent such as an organosilicon derivative for the purpose of hydrophobization, if necessary. The treated powder is treated with the above-mentioned treatment agent that reacts with or physically adsorbs the silicate fine powder. Examples of such treatment agents include hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylsilane, allyl phenyldichlorosilane, and benzyldimethylchlorosilane. Silane, promomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilylbutane, trimethylsilylbutane, triorganosilylacrylate, vinyldimethylacetoxysilane , dimethylethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divinyltetramethyldisiloxane,
1.3-diphenyltetramethyldisiloxane, and 1
Examples include dimethylborisiloxane, which has 2 to 12 siloxane units per molecule and each terminal unit contains a hydroxyl group bonded to one SL. These are 1
It can be used as a species or a mixture of two or more.

Finally, the degree of hydrophobicity of the treated silica fine powder was determined to be 30 as measured by methanol titration test.
When the developer is hydrophobized so as to exhibit a value in the range of 80 to 80, the amount of triboelectric charge of the developer containing such fine silica powder becomes sharp and uniformly positive, which is preferable. Here, in the methanol titration test, the degree of hydrophobization of the silica fine powder having a hydrophobized surface is confirmed.

The "methanol titration test" specified herein for evaluating the degree of hydrophobicity of the treated silica fine powder is carried out as follows. 0.2g of silica fine powder sample in a capacity of 250m
Add to 50 m2 of water in a N Erlenmeyer flask. Methanol is titrated from the puret until the entire amount of silica is wetted. At this time, the solution in the flask is constantly stirred using a magnetic cooler. The end point is observed when the entire amount of fine silica powder is suspended in the liquid, and the degree of hydrophobicity is expressed as the percentage of methanol in the liquid mixture of methanol and water when the end point is reached.

Coloring agents 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, calco oil blue, chrome yellow, quinacridone, Conventionally known dyes and pigments such as benzidine yellow rose bengal, triarylmethane dyes, monoazo dyes, and disazo dyes and pigments can be used alone or in combination.

Examples of the resin used in the present invention include monopolymers of styrene and its substituted products such as polystyrene, poly-P-chlorostyrene, and polyvinyltoluene;
-Chlorstyrene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylic ester copolymer, styrene-methacrylic ester copolymer, styrene-101 chloromethyl methacrylate copolymer Polymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isobrene copolymer Styrenic copolymers such as styrene-acrylonyl/liluindene copolymers; polyvinyl chloride, phenolic resins, naturally modified phenolic resins, natural resin-modified maleic acid resins, acrylic resins, methacrylic resins, polyvinyl acetate, silicones Resin, polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral, terbene resin, coumaron indene resin,
Petroleum-based resins can be used.

Further, crosslinked styrenic copolymers are also preferred binder resins.

Examples of comonomers for the styrene monomer of the styrenic copolymer include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, and methacrylic acid. , methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylic nitrile, acrylamide, etc., or substituted products thereof; e.g., maleic acid, butyl maleate, Dicarboxylic acids with double bonds such as methyl maleate, dimethyl maleate, etc.; vinyl esters such as vinyl chloride, vinyl acetate, vinyl benzoate, etc.; e.g., ethylene, brobylene, butylene, etc. Ethylene-based olefins: Vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, etc.; Vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, etc.; Vinyl monomers such as Apparently two or more are used.

As the crosslinking agent, derivatives having two or more polymerizable double bonds are mainly used, such as aromatic divinyl derivatives such as divinylbenzene and divinylnaphthalene; for example, ethylene glycol diacrylate,
Carboxylic acid esters having two double bonds such as ethylene glycol dimethacrylate and 1,3-butanediol dimethacrylate; divinyl derivatives such as divinylaniline, divinyl ether, divinyl sulfide, and divinyl sulfone; Derivatives having a vinyl group are used alone or as a mixture.

In addition, when using a pressure fixing method, it is possible to use a binder resin for pressure fixing toner, for example, polyethylene 5
Examples include polypropylene, polymethylene, polyurethane elastomer, ethylene-ethyl acrylate copolymer, ethylene-vinyl acetate copolymer, ionomer resin, styrene-butadiene copolymer, styrene-isobrene copolymer, linear saturated polyester, and paraffin.

Furthermore, the toner of the present invention is used in combination with a carrier. As the carrier that can be used in the present invention, known carriers can be used, such as iron powder, ferrite, magnetic powder such as nickel powder, glass beads, etc., and carriers whose surfaces are treated with resin etc. Those who have done so will be listed. Also,
Examples of the resin that coats the carrier surface include styrene-acrylic ester copolymer, styrene-methacrylic ester copolymer, acrylic ester copolymer, methacrylic ester copolymer, silicone resin, fluorine-containing resin, and polyamide resin. , ionomer resin, polyphenylene sulfide resin, or a mixture thereof can be used.

Further, the toner for an electrostatic image developer of the present invention can also be used as a magnetic toner by containing a magnetic material. Magnetic materials used include iron oxides such as magnetite, gamma iron monoxide, ferrite, and iron-rich ferrite; metals such as iron, cobalt, and 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 0.1 to lpm
, preferably about 0.1 to 0.5 #Lm, and the amount to be contained in the magnetic toner is 40 to 150 parts by weight, preferably 60 to 120 parts by weight, based on the ioo parts by weight of the binder resin component. It is.

The toner of the present invention may contain additives, if necessary. Examples of additives include lubricants such as zinc stearate, abrasives such as cerium oxide and silicon carbide, flow agents such as aluminum oxide, anti-caking agents, and conductivity imparters such as carbon black and tin oxide. There is a drug.

Further, fine powder of a fluorine-containing polymer such as fine powder of polyvinylidene fluoride is also a preferable additive from the viewpoint of fluidity, polishability, charging stability, and the like.

In addition, in order to improve mold releasability during hot roll fixing, waxy substances such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, carnauba wax, Sasol wax, paraffin wax, etc.
It is also one of the preferred embodiments of the present invention to add about 5% by weight to the toner.

In manufacturing the toner according to the present invention, the toner constituent materials as described above are sufficiently mixed using a ball mill or other mixer, then thoroughly kneaded using a heat kneader such as a hot roll kneader or an extruder, and then cooled and solidified. Preferably, the toner is obtained by dissolving the binder resin, mechanically crushing, or classifying the toner. Another method is to obtain the toner by dispersing the constituent materials in a binder resin solution overnight and then spray drying; Mix the desired monomer with the specified material and emulsify it/! A polymerization toner production method in which a toner is obtained by polymerizing the three compounds; or, in a so-called microcapsule toner consisting of a core material and a shell material, a method in which a predetermined material is contained in the core material, the shell material, or both; The following methods can be applied. Furthermore, the toner according to the present invention can be produced by sufficiently mixing desired additives with a mixer such as a Henschel mixer, if necessary.

The toner of the present invention can be used in all conventionally known methods for developing electrostatic charge images in electrophotography, electrostatic recording, electrostatic printing, and the like.

The p-aminopyridinium derivative of the present invention can be made light in color and has good positive triboelectric charging properties. Also,
By externally adding the positively chargeable silica fine powder, it is possible to prevent contamination of the l·ner carrier by the p-aminopyridinium derivative, and also to improve the density uniformity of the solid image.

Therefore, the toner of the present invention is less likely to cause image quality deterioration due to continuous copying, and can provide images with excellent density uniformity.

[Examples] Hereinafter, the present invention will be specifically explained with reference to Examples, but these are not intended to limit the present invention in any way. Note that all parts in the following formulations are parts by weight.

10 parts of styrene/butyl methacrylate copolymer The above materials were thoroughly mixed in a blender, and then kneaded in a twin-screw kneading extruder set at 150°C.

The obtained mixed material was cooled, coarsely pulverized with a cutter mill, and then finely pulverized with a pulverizer using a jet stream.
The obtained finely pulverized powder was classified using a fixed wall type wind classifier to refine the classified powder.

Furthermore, the obtained classified powder was strictly classified and removed at the same time to remove ultra-fine powder and coarse powder using a multi-division classification device (elbow jet classifier manufactured by Nippon Steel Mining Co., Ltd.) that utilizes the Coanda effect. A black fine powder was obtained.

To this black fine powder, 0.4% by weight of silica (140 m"/g) treated with silicone oil modified with amino groups was added.
A toner was obtained by mixing.

A developer was prepared by mixing 5 parts of this black fine powder with 100 parts of iron powder carrier having an average particle size of 50 to 80H. Next, a negative electrostatic image is formed on the OPC photoreceptor by a conventionally known electrophotographic method, and this is developed using the above-mentioned developer using a magnetic brush method to create a toner image, which is transferred to plain paper. , heat-fixed.

The obtained image had a sufficiently high density of 1.35 and was clear. Further, the density after copying 10,000 sheets was 1.33, and no decrease in density was observed. Also. The density uniformity of the black and white images was also excellent. When the amount of triboelectric charge was measured using the blow-off method, it was found to be 10.4μc/
g, io. After copying oooo sheets, it was 11.1 pc/g and did not decrease.

A toner was obtained in the same manner as in Example 1, except that 3 parts of benzylmethylhexadecyl ammonium chloride was used in place of 2 parts of Derivative Example (1) used in Example 1.

Using this toner, an image was obtained in the same manner as in Example 1.

From the beginning, the image density was slightly low at 1.15, and fog was noticeable. Although 5,000 sheets were continuously copied, no increase in image density was observed. The amount of triboelectric charge measured by the blow-off method was as low as 7.8 μcog.

After thoroughly mixing the above materials in a blender, they were kneaded in a twin-screw kneading extruder set at 150°C.

The obtained kneaded material was cooled and coarsely pulverized using a cutter mill, then finely pulverized using a pulverizer using JETSU 1 and air flow, and the obtained pulverized powder was classified using a fixed wall type wind classifier. The classified material was purified.

Furthermore, the obtained classified powder is divided into two parts using the Coanda effect (Nippon Steel Mining Co., Ltd.'s Elbosier/Soto classifier).
The ultrafine powder and the coarse powder were simultaneously strictly classified and removed to obtain a blue fine powder with a volume average particle size of 9.7p+n.

100 parts of the obtained blue fine powder was treated with N-dimethylaminopropyltrimethoxysilane (16
0 m2/g) were mixed to obtain a toner.

Next, 5 parts of the obtained toner was added to 100 parts of a fluorine-acrylic coated ferrite carrier having an average particle size of 65 pm.
These parts were mixed to prepare a developer.

This developer was copied using a commercially available copying machine (trade name: NP-5540 manufactured by Canon@).

A bright blue image with a density of 1.36 was obtained.

Even after copying 10,000 sheets, a bright blue image with a density of 1.37 was obtained, and no image deterioration was observed. Also,
The density uniformity in the background image was also excellent.

In addition, the amount of triboelectric charge of this developer by the blow-off method is 2
5 ILc/g, and 33 lL even after copying 10,000 sheets.
Although a slight increase in c/g was observed, the results were good.

The blue fine powder used in Example 2 was used as a toner without external addition of silica. A developer was obtained in the same manner as in Example 2, and a copying test was conducted.

Initially, an image with a density of 1.21 was obtained, but the image density gradually decreased to 0.98 after copying 10,000 sheets. When the amount of triboelectric charge of the developer was measured by the blow-off method, the initial value was 29 II. c/g, but it decreased to 14 B/g after copying 10,000 sheets.

Ta. The amount of triboelectric charge by the blow-off method is 25#Lc/g
Almost no deterioration was observed even after running 10,000 sheets.

Using the above materials and the same method as in Example 2, a red fine powder with a volume average particle size of 9.3 μm was obtained.

0.6 part of the dry silica used in Example 2 was mixed with 100 parts of the obtained red fine powder to obtain a toner.

Next, a developer was obtained in the same manner as in Example 2, and a copying test was conducted.

A bright red image with a density of 1.30 was obtained from the initial stage.

No deterioration in image quality was observed even after a 10,000-copy test, and density uniformity in solid images was excellent. Using the above material and using the same method as in Example 2, a volume average particle size of 9.3p was obtained.
A fine green powder of m was obtained.

0.6 part of the dry silica used in Example 2 was mixed with 100 parts of the obtained green fine powder to obtain a toner.

Next, a developer was obtained in the same manner as in Example 2, and a copying test was conducted.

A bright green image with a density of 1.24 was obtained from the initial stage.

Even after a 10,000 copy test, no deterioration in image quality was observed, and the density uniformity of the solid images was excellent. The amount of triboelectric charge by the blow-off method was 21gc/g, 10,
Almost no decrease was observed after running for 000 sheets.

After thoroughly mixing the above materials in a blender, they were kneaded in a twin-screw kneading extruder set at 150°C.

The obtained mixed material was cooled, coarsely pulverized with a cutter mill, and then finely pulverized with a pulverizer using a jet stream.
The obtained finely pulverized powder was classified using a fixed wall type wind classifier.

Furthermore, the obtained classified powder was strictly classified and removed at the same time using a multi-division classifier (Nippon Steel Mining Co., Ltd. Elbow Classifier) that utilizes the Coanda effect to obtain a volume average particle size of 11.
8 gm of fine powder was obtained.

100 parts of the obtained fine powder was subjected to a positively charged hydrophobic dry process (
Add 0.4 parts of BET specific surface area 200 m”/g,
The mixture was mixed using a Henschel mixer to obtain a positively chargeable toner.

Next, Fusso Acrylic Co., Ltd. with an average particle size of 65 gm was added.
- 4 parts of the obtained toner were mixed with 100 parts of toferrite carrier to prepare a developer.

This developer was applied to a commercially available color electrophotographic copying machine CLC-1.
A copying test was conducted using a modified machine manufactured by Canon Corporation (manufactured by Canon ■) in which the OPC photosensitive drum was replaced with a non-quality silicone drum.

As a result, a bright blue image with a density of 1.35 was obtained from the initial stage, and no deterioration was observed after 5,000 copies were made.

5 parts of the copper phthalocyanine pigment (C.■, Pigment Blue 15) in Example 5 was added to a quinacridone pigment (C.I.
．． A fine powder with a volume average particle diameter of 11.9 ILm was obtained in the same manner as in Example 5 except that the part was changed to
Furthermore, silica was mixed to obtain a positively charged toner.

Next, the same carrier as in Example 5 was mixed in the same ratio to prepare a developer.

This developer was subjected to a copying test in the same manner as in Example 5. As a result, a bright magenta image with a density of 1.31 was obtained from the initial stage. No deterioration of the image was observed after copying s, ooo copies.

5 parts of the copper phthalocyanine pigment (C. ■. Pigment Blue 15) in Example 5 was added to C.I. I. Same as Example 5 except that Pigment Yellow was changed to 173.5 parts with a volume average particle size of 11. A fine powder of IILm was obtained, and silica was added to it.
A positively charged toner was obtained.

Next, the same carrier as in Example 5 was combined in the same ratio to obtain a developer.

This developer was subjected to a copying test in the same manner as in Example 5. As a result, a bright magenta image with a density of 1.27 was obtained from the initial stage. No image deterioration was observed even after 5,000 copies were made.

History 1 Same as Example 5 except that 5 parts of the copper phthalocyanine pigment (C. ■, Pigment Blue 15) was changed to 3 parts of carbon black, except that the volume average particle size was 11.4 #L.
A fine powder of m was obtained, and silica was further mixed therein to obtain a positively charged toner.

Next, the same carrier as in Example 5 was mixed in the same ratio to prepare a developer.

This developer was subjected to a copying test in the same manner as in Example 5. As a result, a bright black image with a density of 1.35 was obtained from the initial stage. No image deterioration was observed even after 5,000 copies were made.

A full-color image was obtained using the cyan, magenta, yellow and black developers used in Examples 5 to 8, and a bright full-color image with excellent gradation was obtained.

After thoroughly mixing the above materials in a blender, they were kneaded in a twin-screw kneading extruder set at 150°C.

The obtained mixed material was cooled, coarsely pulverized with a cutter mill, and then finely pulverized with a pulverizer using a jet stream.
The resulting finely pulverized powder was classified using a fixed wall type wind classifier to refine the classified powder.

Furthermore, the obtained classified powder was strictly classified and removed at the same time to remove ultra-fine powder and coarse powder using a multi-division classification device (elbow jet classifier manufactured by Nittetsu Mining Co., Ltd.) that utilizes the Coanda effect, resulting in a volume average particle size of 8.1 pm. A black fine powder was obtained.

100 parts of this black fine powder was mixed with positively charged hydrophobic dry powder (
BET specific surface area 200m2/g) 0.5 part was added,
The mixture was mixed in a Henschel mixer to obtain a positively charged, semi-magnetic toner.

The obtained magnetic toner was transferred to a commercially available electrophotographic copying machine NP-35.
25 (manufactured by Canon Inc.), a 5,000 copy test was conducted.

Clear images with good resolution and little fog were obtained with an image density of 1.33 from the initial stage. Further, the image density after copying 5,000 sheets was as good as 1.31, and no decrease in density or deterioration of image quality was observed.

After thoroughly mixing the above materials in a blender, they were kneaded in a twin-screw kneading extruder set at 150°C.

The obtained mixed material was cooled, coarsely pulverized with a cutter mill, and then finely pulverized with a pulverizer using a jet stream.
The obtained finely pulverized powder was classified using a fixed wall type wind classifier to refine the classified powder.

Furthermore, the obtained classified powder was strictly classified and removed at the same time to remove ultra-fine powder and coarse powder using a multi-division classifier (elbow jet classifier manufactured by Nittetsu Mining Co., Ltd.) that utilizes the Coanda effect, resulting in a volume average particle size of 11.3 gm. A black fine powder was obtained.

Add 100 parts of this black fine powder to positively charged hydrophobic dry silica (
BET specific surface area 200m2/g) 0.4 part was added,
A positively charged one-component magnetic toner was obtained by mixing in a Henschel mixer.

The obtained magnetic toner was transferred to a commercially available electrophotographic copying machine NP-55.
40 (manufactured by Canon Inc.) and 10,001) copies were tested.

A clear image with an image density of 1.37 and little fog was obtained from the beginning. Also, the image density after copying 10,000 sheets was 1.
33, which was good, and no decrease in density or deterioration in image quality was observed.

[Effects of the Invention] As described above, by using the toner of the present invention that uses a p-aminoviridinium derivative and positively charged silica fine powder in combination, high-quality images can be stably obtained over a long period of time. .

Claims (3)

[Claims] (1) Fine powder particles consisting of at least a pyridinium compound represented by the following general formula, a colorant, and a binder resin,
A toner for developing positively charged electrostatic images, which is characterized by externally adding positively charged silica fine powder. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [However, R_1 and R_2 represent H, an alkyl group, an aryl group, or an aralkyl group, and may be the same or different. Further, R_1 and R_2 may form a ring. R
_3 represents an alkyl group, an aryl group, an aralkyl group, or a cyclic alkyl group. X^- is an anion such as an organic sulfonate ion, an organic sulfate ion, an organic phosphate ion, an organic carboxylate ion, an organic borate ion, a polyacid ion, a heteropolyacid ion, a tetrafluoroporate ion, a hexafluorophosphate ion, etc. shows. ] (2) Positively chargeable silica fine powder has the formula R_
mSiY_n [wherein R represents an alkoxy group or halogen, m represents an integer of 1 to 3, Y represents an amino group or an organo group having at least one nitrogen atom, and n represents m+n = 4 Indicates an integer from 1 to 3. ] Claim (1)
) The toner for developing positively charged electrostatic images. (3) The positively chargeable electrostatic charge according to claim (1), wherein the positively chargeable silica fine powder is obtained by treating the silica fine powder with a silicone oil having an organo group or an amino group having a nitrogen atom in a side chain. Toner for image development.