JPH03105355A - Toner for developing electrostatic charge image - Google Patents

Abstract

PURPOSE:To obtain a stable image without being affected by environmental conditions by using the toner for electrostatic development contg. the salicylic acid resin expressed by a specific formula. CONSTITUTION:The salicylic acid resin expressed by the formula is used as a charge control agent. In the formula, X is halogen, alkoxy group; Y is H, hydroxy group, amino group, alkyl group, halogen, alkoxy group; R1, R2 indepen dently denote H, 1 to 6C alkyl group or alkoxy group and may form a ring; n>2. The polymerized salicylic acid compd. has no sublimatability and is higher in the negative triboelectrostatic charge quantity thereof when the compd. than the compd. made into the monomer. This compd. is substantially colorless. Further, the dispersibility in a binder resin is improved and the triboelectraostatic charge between the toner particles is uniformized. The forma tion of reverse electrostatic charge particles is suppressed and the generation of fogging is obviated. The contamination of a toner carrier is decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a new toner and a charge control agent for toner for developing electrostatic images in electrophotography, electrostatic recording, electrostatic printing, and the like.

[Prior art J As a conventional electrophotographic method, U.S. Patent No. 2,297,691
No., Special Publication No. 42-23910 and Special Publication No. 43-2
Various methods are described in Japanese Patent No. 4748 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 a method using a two-component developer and a method using a one-component developer.

As toners applied to these dry developing 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 μm are used as toner. As the magnetic toner, one containing magnetic particles such as magnetite is used. Further, in the case of a system using a two-component 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.

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 with this method, the toner's chargeability is small, so the images obtained by development are prone to fogging and are unclear. becomes. Therefore, it is common to add a substance called a charge control agent to the toner in order to further impart triboelectric charging properties.

Charge control agents known in the art today include those with negative triboelectrification properties, such as metal complexes of monoazo dyes, metal complexes of salicylic acid, metal complexes of naphthoic acid, metal complexes of dicarboxylic acids, and copper phthalocyanine pigments. and so on.

[Problems to be Solved by the Invention] Many of the charge control agents described above have sufficiently high charge imparting ability, but are colored and cannot be used in color toners. In addition, some control agents tend to contaminate toner carriers such as sleeves or carriers, so toners using these agents have a lower frictional f-electricity as the number of copies increases, causing a decrease in image density. Easy to do. Further, since the amount of triboelectric charge of some types of control agents varies greatly depending on the binder resin used, there are restrictions on the binder resins or other materials that can be used. Furthermore, although they are excellent in imparting frictional charge, they often lack controllability and tend to be excessively charged. At present, there is a strong demand for the development of a charge control agent that satisfies all of these requirements.

An object of the present invention is to provide an excellent toner using a charge control agent that solves the above problems.

That is, between toner particles or between toner and carrier,
A toner that can reproduce stable images that are stable in the amount of triboelectric charge between the toner and a toner carrier such as a sleeve in the case of one-component development without being affected by changes in temperature or humidity, and are not affected by changes in environmental conditions. It is to provide.

A further object of the present invention is to provide a developer in which the toner is uniformly dispersed or dissolved in the binder phase resin, the toner particles are uniformly charged, and a clear image without fogging is produced.

[Means and Effects for Solving the Problems] A feature of the present invention is that a salicylic acid resin represented by the general formula (I) is used as a charge control agent.

General formula (I) (wherein, X represents a halogen or alkoxy group, Y represents hydrogen, a hydroxy group, an amino group, an alkyl group, a halogen, or an alkoxy group, and Rl and R2 each independently represent hydrogen or a carbon number of 1 - 6 alkyl or alkoxy groups, which may form a ring (n is an integer indicating a degree of polymerization of 2 or more). A two-component toner is disclosed.

However, salicylic acid itself has sublimation properties and does not have sufficient negative triboelectric charging properties, so its uses are extremely limited. On the other hand, some metal complexes of salicylic acid compounds have excellent triboelectric charging properties and are generally widely used. However, the triboelectrification property of a metal complex does not depend only on the ligand, and the amount of charge and even the positive or negative sign often change depending on the central metal. Therefore, it is not possible to predict the tribo-11F conductivity of the ligand from the results of a metal complex.

The present inventors investigated salicylic acid derivatives based on their own ideas and found that the amount of negative triboelectrification can be increased by introducing a substituent into salicylic acid. However, like salicylic acid, these salicylic acid derivatives also have sublimation properties and are not suitable for producing toners at high temperatures.

Therefore, by increasing the amount of salicylic acid compound as shown in formula (T), not only did the sublimation property disappear, but when it was made into toner, the amount of negative triboelectric charge was higher than that of the corresponding monomer, and it was considered to be virtually colorless. I found that the color was so light that I could almost imagine it.

Furthermore, since the dispersibility in the binder resin is improved compared to conventional metal compounds, the frictional charging between toner particles becomes uniform, the generation of oppositely charged particles is suppressed, and fogging does not occur. Also, sleeve, key. It was possible to reduce the contamination of toner carriers such as Yaria.

Furthermore, the dependence of images on the environment is less than that of conventional metal compounds, and images with sufficient density can be obtained even under high temperature conditions or low temperature and low humidity conditions.

As described above, it was discovered that the toner containing the salicylic acid resin of the present invention has superior properties compared to the conventional L-toner containing a charge control agent, and the inventors were defeated by the invention.

One of the monomers used in the synthesis of the salicylic acid resin of the present invention is a salicylic acid compound represented by formula (I+).

Y Y represents hydrogen, a hydroxy group, an amino group, an alkyl group, a halogen, or an alkoxy group. The alkyl group preferably has 24 or less carbon atoms. When the number of carbon atoms exceeds 24, the degree of polymerization of the product decreases, and the yield also decreases.

Considering ease of synthesis, the alkoxy group preferably has 6 or less carbon atoms.

On the other hand, it is the xylene compound represented by the following formula (■!) that acts with the salicylic acid compound represented by the above formula (II) to form the salicylic acid resin of the present invention.

Example H2 of salicylic acid compound Considering the ease of synthesis, the alkoxy group preferably has 6 or less carbon atoms. When the number of carbon atoms exceeds 6, by-products are likely to be produced, which impairs the charging performance of the resulting resin. R+ and Rz each independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group, and may form a ring.

Specific examples of salicylic acid compounds and xylene compounds used in wood invention are shown below, but these are representative examples taking into consideration the ease of the synthesis method, etc., and are not intended to limit the compounds of the present invention in any way.

(Left space below) Examples of xylene compounds: N3 (m is an integer indicating a degree of polymerization of 2 or more) The salicylic acid resin of the present invention is prepared by a known method from a salicylic acid compound shown by formula (II) and a xylene compound shown by formula (III). can be synthesized using

When αα dihalogenoxylene is used as the xylene compound of formula (III), the desired salicylic acid resin can be obtained by reacting zinc halide or the like with xylene in an equimolar amount to salicylic acid.

In addition, when αα dialkoxyxylene is used as the xylene compound of formula (m), an acid such as hydrochloric acid or sulfuric acid or a free delta-lat type catalyst such as zinc chloride or ferric chloride may be reacted with salicylic acid and the xylene compound. The desired salicylic acid resin can be obtained.

Specific examples of the salicylic acid resin of the present invention are shown below, but these are representative examples in consideration of the ease of the synthesis method, etc., and are not intended to limit the compounds of the present invention in any way.

Compound Examples Methods for incorporating the salicylic acid resin of the present invention into a toner include a method of adding it inside the toner and a method of adding it externally. The amount of these compounds used 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. However, preferably 0.1 to 10 parts by weight, more preferably 0.1 parts by weight per 100 parts by weight of the binder resin.
It is used in a range of 5 parts by weight. Also, when adding externally,
The amount is preferably 0.01 to 10 parts by weight per 100 parts by weight of the resin, and it is particularly preferable to fix it to the toner particle surface by a mechanochemical method or the like.

Further, the compound used in the present invention can also be used in combination with a conventionally known charge control agent.

Coloring agents used in the present invention include carbon black, lamp black, iron black, ultramarine blue, nigrosine dye, aniline blue, phthalocyanium blue, phthalocyanine green, Banza Yellow 01 Rhodamine 6G, lake, calco oil blue, chrome yellow, quinacridone, benzidine. Conventionally known dyes and pigments such as 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, polyp-chlorostyrene, and polyvinyl luene;
p-Chlorstyrene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethacrylic acid Methyl copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer,
Styrenic copolymers such as styrene-vinylethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isobrene copolymer, and styrene-acrylonitrile-indene copolymer Polyvinyl chloride, phenolic resin, naturally modified phenolic resin, natural resin modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin, xylene resin, Polyvinyl butyral, terbene resin, coumaron indene resin, petroleum resin, etc. can be used.

Further, crosslinked styrenic copolymers are also preferred binder resins.

Examples of comonomers for the styrene monomer in the styrenic copolymer include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, and methacrylate. Acid, monocarboxylic acid having a double bond such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, etc., or substitutes thereof; e.g., maleic acid, butyl maleate , methyl maleate, dimethyl maleate, etc., and their substituted dicarboxylic acids; for example, vinyl chloride, vinyl acetate,
Vinyl esters such as vinyl benzoate; ethylene olefins such as ethylene, brobylene, butylene; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, etc.; vinyl methyl ether, vinyl ethyl ether, Vinyl ethers such as vinyl isobutyl ether and the like may be used alone or in combination of two or more.

As the crosslinking agent, compounds having two or more polymerizable double bonds are mainly used, such as aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; for example, ethylene glycol diacrylate and ethylene glycol diacrylate. methacrylate, 1,3-butanediol dimethacrylate, etc.
Carboxylic acid esters having the following properties: divinyl compounds such as divinylaniline, divinyl ether, divinyl sulfide, and divinyl sulfone; and compounds having three or more vinyl groups; 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, such as polyethylene,
Polypropylene, polymethylene, polyurethane elastomer, ethylene-ethyl acrylate copolymer, ethylene-vinyl acetate copolymer, ionomer resin, styrene-butadiene copolymer, styrene-isobrene copolymer, linear saturated polyester, paraffin, etc.

The toner of the present invention can contain a magnetic material and can be used as a magnetic toner. The magnetic materials contained in the magnetic toner of the present invention include magnetite, gamma iron monoxide, 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, zinc, antimony, beryllium, bismuth, cadmium, calcium,
Examples include alloys with metals such as manganese, selenium, titanium, tungsten, and panadium, and mixtures thereof.

It is desirable that these ferromagnetic materials have an average particle diameter of about 0.1 to 1 μm, preferably about 0.1 to 0.5 μm, and the amount to be contained in the magnetic toner is 40 to 150 parts by weight per 100 parts by weight of the resin component. It is preferably 60 to 120 parts by weight per 100 parts by weight of the resin component. Further, when the toner of the present invention is used as a two-compound type developer, it is used in combination with carrier powder. As carriers that can be used in the present invention, known carriers can be used, such as magnetic powders such as iron powder, ferrite powder, and nickel powder, glass beads, etc., and carriers whose surfaces have been treated with resin, etc. etc. In addition, 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, Boria resin,
Ionomer resins, polyphenylene sulfide resins, etc. or mixtures thereof can be used.

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 fine silica powder and aluminum oxide, anti-caking agents, and carbon black and tin oxide. There are conductivity imparting agents.

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 forms of the wood 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, and then thoroughly kneaded using a heat kneader such as a hot roll kneader/extruder. It is preferable to obtain the toner by mechanical crushing or classification.Other methods include dispersing the structural material in a binder resin solution and then spray drying it to obtain the toner. A polymerization toner production method in which a toner is obtained by mixing a predetermined material with the JP-mer to be constituted to form an emulsified suspension, and then fusing the mixture to obtain a toner; or in a so-called microcapsule toner consisting of a core material and a shell material, core material or shell material,
Alternatively, a method in which a predetermined material is contained in both of these materials can be applied. Furthermore, the toner according to the present invention can be produced by sufficiently mixing desired additives, if necessary, with a mixer such as a Henschel mixer.

The toner of the present invention can be used in all conventionally known methods for developing to visualize electrostatic charge images in electrophotography, electrostatic recording, electrostatic stamps, etc.

The salicylic acid resin having a substituent according to the present invention is colorless or has a color so light as to pose no problem in practical use, and has sufficient negative triboelectrification properties. Furthermore, the dispersibility in the binder resin was improved compared to conventionally known metal compounds. Furthermore, the sublimation property of salicylic acid or salicylic acid derivatives could be completely solved.

Therefore, the toner containing the salicylic acid resin having a substituent group according to the present invention as a charge control agent can always provide good and stable images because there is little contamination of toner carriers such as sleeves or carriers. It can also be used as a charge control agent for color toners to provide color images.

Since it has no sublimation property and has excellent thermal stability, toner can be stably produced and supplied without the need for special measures in the toner manufacturing process or in the selection of other raw materials.

[Examples] Hereinafter, the present invention will be specifically explained using Examples, but these are not intended to limit the invention in any way.

All parts in the following formulations are parts by weight. Example 1 The above materials were thoroughly mixed in a blender and then kneaded in a twin-screw kneading extruder set at 130°C.

The obtained kneaded material was cooled and coarsely pulverized using a cutter mill, and then finely pulverized using 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 simultaneously classified and removed by a multi-division classifier (Elbow Jet classifier manufactured by Nippon Steel Mining Co., Ltd.) using the Coanda effect to remove ultra-fine powder with a volume average particle size of 11.
A fine powder of 2 μm was obtained.

Silica fine powder (BET specific surface area 200
m''/g) was added and mixed in a Henschel mixer to prepare a toner.

Next, 10 parts of the obtained toner were mixed with 100 parts of an acrylic coated ferrite carrier having an average particle diameter of 65 μm to prepare a developer.

This developer was applied to a commercially available copying machine (product name NP-6650, manufactured by Canon ■) under an environmental condition of 23°C/60%.
When I did a copy test, l. Thirty good quality images were obtained. Using the above developer, 4,000 sheets were continuously copied and the durability was examined. As a result, good images comparable to the initial images were obtained.

Next, copying tests were conducted under environmental conditions of 15°C/10% and 35°C/83%, and similarly good results were obtained. After thoroughly mixing the above materials in a blender, they were kneaded in a twin-screw kneading extruder set at 130°C.

The obtained kneaded material was cooled, coarsely pulverized using a cutter roll, and then finely pulverized using 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 is processed into ultrafine powder at the same time using a multi-division classifier (Elbow Jet classifier manufactured by Nippon Steel Mining Co., Ltd.) that utilizes the Coanda effect. & Densely classified and removed to achieve a volume average particle size of 11
．． A fine powder of 6 μm was obtained. To 100 parts of the obtained fine powder, 0.4 part of silica fine powder (BET specific surface area: 300 m2/g) which had been hydrophobized with hexamethyldisilazane was added and mixed in a Henschel mixer to obtain a magnetic toner.

This toner was applied to a commercially available copying machine (product name NP-6650, manufactured by Canon ■) under an environmental condition of 23°C/60%.
When a copying test was carried out, the image density was l. 34. Clear images without fog or roughness were obtained. Furthermore, when we checked the durability performance by continuously copying 30,000 sheets, we found that the image density was 1.33.
A good image comparable to the initial image was obtained. Further, when the amount of triboelectric charge of the toner on the developing sleeve was measured, it was -10.3 .mu.c/g at the initial stage and -10.0 .mu.c/g after 30,000 copies, and almost no sleeve contamination was observed.

Then, when a copying test was carried out under an environmental condition of 15° C./10%, similarly high density and good quality images were obtained.

Similarly, good results were obtained in a continuous copying test of 30,000 sheets.

When the same copying test and continuous copying test were conducted under the environmental conditions of 35° C./85%, good results were obtained. Furthermore, after allowing this toner to stand for one month under these environmental conditions, the same copying test and continuous copying test were conducted, and the results were satisfactory and without any problems.

Add 2 parts of Compound Example (3) in Example 2 to Compound Example (2)
A fine powder with a volume average particle diameter of 11.1 μm was obtained in the same manner as in Example 1 except that the amount was changed to 3 parts. To 100 parts of this fine powder,
Fine silica powder (B) hydrophobized with silicone oil
0.4 part of ET specific surface area (Zoom2/g) was added and mixed in a Henschel mixer to obtain magnetic 1.ner.

This toner was applied to a commercially available copying machine (product name NP-6650, manufactured by Canon ■) under an environmental condition of 23°C/60%.
When a copying test was carried out, the image density was as high as 1.32, and a clear image without fogging or roughness was obtained. followed by 2
When we checked the durability by making 10,000 copies continuously, we found that the images were as good as the initial images. In addition, when we measured the amount of triboelectric charge of the toner on the developing sleeve, we found that
-9.3 μe/g in the initial stage, - after copying 20,000 sheets.
At 9.1 μc/g, almost no sleeve contamination was observed. Then, when a copying test was carried out under an environmental condition of 15° C./10%, similarly high density and good quality images were obtained. Similarly, good results were obtained in a continuous copying test of 20,000 sheets.

The same copying test and continuous copying test were conducted under environmental conditions of 35° C. and 785%, and good results were obtained.

Furthermore, after leaving this toner for one month under these environmental conditions,
I conducted the same copying test and continuous copying test, and the results were satisfactory with no problems. XΔri1 The above materials were thoroughly mixed in a blender, and then kneaded in a twin-screw kneading extruder set at 150°C.

The obtained kneaded material was cooled and coarsely pulverized using a cutter mill, and then finely pulverized using a pulverizer using a jet stream.
The resulting finely pulverized powder was classified using a fixed wall type wind classifier. Furthermore, the obtained classified powder is strictly classified and removed at the same time using a multi-division classifier that utilizes the Coanda effect (Elbow Jet classifier manufactured by Nippon Steel Mining Co., Ltd.), with a volume average particle size of 8-5 μm.
A fine powder of m was obtained.

100 parts of the obtained fine powder was treated with silica powder (BET specific surface + R 3
00m2/g) was added and mixed using a Henschel mixer to prepare a toner.

Next, 6 parts of the obtained toner were mixed with 100 parts of the acrylic coated ferrite carrier having an average particle size of 65 μm to prepare a developer.

This developer was applied to a commercially available color electrophotographic copying machine (LC-1
(manufactured by Canon ■) was used for copying tests.

As a result, under an environmental condition of 23° C./60%, a bright black image with an image density of 1.42 was obtained from the initial stage, and no deterioration was observed after 10,000 copies were made.

Next, a copying test was conducted under environmental conditions of 15° C./10%, and an image with a high density of 1.39 was obtained from the initial stage. Furthermore, even under the environmental conditions of 32°C/85%, the concentration l,4
3 good images were obtained.

A fine powder with a volume average particle size of 8.6 μm was obtained in the same manner as in Example 4, except that 5 parts of carbon black in Example 4 was replaced with 4 parts of copper phthalocyanine pigment (CR Pigment Blue 15). Furthermore, silica was mixed to obtain a toner. Next, the same carrier as in Example 4 was mixed in the same ratio,
It was used as a developer.

A copying test was conducted using this developer in the same manner as in Example 4. As a result, under the environmental condition of 23°C and 760%, a good blue image with a density of 1.39 and no fog was obtained from the beginning. No deterioration in image quality was observed even after copying 10,000 copies.

Copying tests were also conducted under environmental conditions of 35°C/85% and 15°C/10%, and good results were obtained as in the case of 23°C/60%.

Example 6 A fine powder with a volume average particle diameter of 8.8 μm was obtained in the same manner as in Example 4 except that 5 parts of the carbon black manufactured by the company in Example 4 was replaced with 4 parts of a quinacridone pigment (C.I. Pigment Red 122). , further mixed with silica to obtain a toner. Next, the same carrier as in Example 4 was mixed in the same ratio,
It was used as a developer. This developer was subjected to a copying test in the same manner as in Example 4. As a result, under environmental conditions of 23° C./60%, a good magenta image with a density of 1.32 and no fog was obtained from the beginning. No deterioration in image quality was observed even after copying 10,000 copies.

Copying tests were also carried out under the environmental conditions of 35°C/85% and 15°C/10%, and similar good results were obtained as in the case of 23°C/60%.

A fine powder with a volume average particle diameter of 8.9 μm was obtained in the same manner as in Example 4, except that 5 parts of carbon black in Example 4 was changed to 5 parts of 2.9-dimethylquinacridone pigment, and silica was further mixed. I got toner.

Next, mix the same keys and rear as in Example 4 in the same ratio,
It was used as a developer.

This developer was subjected to a copying test in the same manner as in Example 3. As a result, under environmental conditions of 23° C./80%, a good yellow image with a density of 1.39 and no fog was obtained from the beginning. No deterioration in image quality was observed even after copying 10,000 copies.

Copying tests were also conducted under environmental conditions of 35°C/85% and 15°C/10%, and good results were obtained as in the case of 23°C/780%.

Example 8 A full-color image was obtained using the black, cyan, magenta, and yellow developers used in Examples 4 to 7, and a bright full-color image with excellent color mixing and 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 kneaded material was cooled and coarsely pulverized using a cutter wheel, and then finely pulverized using 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 (Elbow Jet classifier manufactured by Nippon Steel Mining Co., Ltd.) that utilizes the Coanda effect, and the volume average particle size was 9.6 μm.
A fine powder of m was obtained.

100 parts of the obtained fine powder was added with silica fine powder hydrophobized with hexamethyldisilazane (BET specific surface area 300 m
0.6 part of the mixture was added and mixed using a Henschel mixer to obtain a toner.

Next, 6 parts of the obtained toner were mixed with 100 parts of an acrylic coated ferrite carrier having an average particle size of 55 μm to prepare a developer.

This developer was applied to a commercially available color electrophotographic copying machine CLC-1.
(manufactured by Canon ■) for copying tests.

As a result, under the environmental conditions of 23° C./60%, a bright black image with an image density of 1.41 was obtained from the initial stage, and no deterioration was observed after 10,000 copies were made.

Next, when a copying test was conducted under environmental conditions of 15° C./10%, an image with a high density of 1.32 was obtained from the initial stage. Furthermore, even under the environmental conditions of 32°C/85%, the concentration l. 4
3 good images were obtained.

[Effects of the Invention] As described above, the toner containing the salicylic acid resin of the present invention as a charge control agent has a uniform amount of frictional 11F charge between toner particles, and provides a good image without fogging. In addition, since contamination of toner carriers such as sleeves and carriers by charge control agents is reduced, images with sufficient density can be obtained and the density is stable even after a large number of copies are made. Furthermore, since the dependence of image density on temperature and humidity is small and changes over time are less likely to occur, quality stability during storage is excellent.

Furthermore, it can be used in color toners because there is little color tone disturbance caused by the charge control agent.

Claims (1)

[Claims] General formula (I) ▲Mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, (R_1 and R_2 each independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group, and may form a ring. n is an integer indicating a degree of polymerization of 2 or more.) Salicylic acid represented by A toner for developing electrostatic images characterized by containing a resin.