JP3111189B2 - Polymerization toner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymerization toner used in a method for visualizing a latent image.

[0002]

2. Description of the Prior Art Electrophotography is disclosed in U.S. Pat. No. 2,297,6.
As described in, for example, US Pat. No. 91/91, a number of methods are known. Generally, a photoconductive substance is used to form an electric latent image on a photoreceptor by various means, and then the latent image is formed. The image is developed using toner, and if necessary, the toner image is transferred to a transfer member such as paper, and then fixed by heating, pressure, or solvent vapor to obtain a copy. Further, as a method of developing using a toner or a method of fixing a toner image,
Conventionally, various methods have been proposed, and a method suitable for each image forming process has been adopted.

Conventionally, as a toner used for these purposes, generally, a coloring agent such as a dye or a pigment is melt-mixed in a thermoplastic resin and uniformly dispersed, and then has a desired particle size by a pulverizer or a classifier. Has been producing toner.

[0004] Although this method can produce fairly good toners, it does have certain limitations, namely the choice of toner materials. For example, the resin colorant dispersion is brittle enough,
It must be able to be comminuted in an economically feasible production equipment. However, if the resin colorant dispersion is made brittle to satisfy these requirements, the particle size range of the particles formed when actually pulverized at high speed tends to be widened, and in particular, a relatively large proportion of fine particles Problem arises. Further, such a highly brittle material is liable to be further pulverized or powdered when used for development in a copying machine or the like. Further, in this method, it is difficult to completely and uniformly disperse solid fine particles such as a colorant in a resin,
Depending on the degree of the dispersion, fog may increase, the image density may decrease, or the color mixing / transparency may be poor. Further, exposure of the coloring agent to the fracture surface may cause fluctuations in development characteristics.

On the other hand, in order to overcome the problems of the toner caused by these pulverization methods, Japanese Patent Publication Nos.
Nos. 10799 and 51-14895 propose a method for producing a toner by a suspension polymerization method. In the suspension polymerization method, a polymerizable monomer, a colorant, a polymerization initiator, and, if necessary, a crosslinking agent, a charge control agent, and other additives are uniformly dissolved or dispersed to form a monomer composition. A continuous phase containing the monomer composition containing a dispersion stabilizer,
For example, the toner particles are dispersed in an aqueous phase using a suitable stirrer, and simultaneously undergo a polymerization reaction to obtain toner particles having a desired particle size.

This method does not include a pulverizing step at all, so that the toner does not need to be brittle, a soft material can be used, and the classification step can be omitted, thereby saving energy. The cost reduction effect is large, such as shortening the time and improving the process yield.

Further, there is an advantage that a colorant is not exposed to the particle surface and uniform triboelectricity is obtained.

However, in recent years, the copier has become more sophisticated,
In consideration of the improvement of the durability and the like accompanying the improvement of the reliability, a phenomenon that the developing property is remarkably reduced when the battery is discharged in a low humidity environment has occurred. This is considered to be due to a decrease in the fluidity of the toner and a deterioration in the chargeability.

As means for solving the above problem, Japanese Patent Application Laid-Open
No. 2-59964 has been proposed, but this method is not sufficiently satisfactory for suspension polymerization toners.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a stable and satisfactory image without lowering the fluidity of the toner and deteriorating the chargeability even under low humidity. Is to provide a polymerized toner.

Another object of the present invention is to provide a polymerization toner having a sharp particle size distribution.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polymerized toner obtained by subjecting a polymerizable monomer system to suspension polymerization in an aqueous medium. A monomer represented by the formula, a polymer of the monomer,
Alternatively, it is achieved by containing a copolymer composed of the monomer and a vinyl monomer, and having a softening point of 40 to 130 ° C. of the wax.

General formula

Embedded image Hereinafter, the present invention will be described in detail.

As a result of intensive studies, the present inventors have obtained a polymerized toner obtained by subjecting a polymerizable monomer system to suspension polymerization in an aqueous medium. Contains a monomer, a polymer of the monomer, or a copolymer of the monomer and a vinyl monomer, whereby the particle size distribution of the toner is sharp, and No deterioration of the fluidity and deterioration of the chargeability of the toner were observed, and it was found that a good image could be stably obtained.

The reason why such effects can be obtained in the toner of the present invention is not necessarily clear, but is presumed as follows.

The presence of the ether and phosphate groups in the general formula at the oil / water interface stabilizes the granulation system and sharpens the particle size distribution. Furthermore, the charge-up development of the tribo under low humidity is prevented because the ether and phosphate groups become leak points. For this reason, it is estimated that even under low humidity, the chargeability of the toner and the fluidity of the toner are stable, and a good image is stably obtained.

The monomer represented by the general formula used in the present invention may be in any form as a monomer, a polymer thereof, or a copolymer with another vinyl monomer. It may be used, but when the monomer is water-soluble, it is preferable to use it as a polymer or a copolymer.

Further, the content of the monomer is preferably 0.01 to 10% by weight of the total amount of the monomer.

Specific examples of the monomer represented by the general formula used in the present invention include the following.

[0020]

Embedded image Monomer 1: Monomer 2: Monomer 3: The polymerizable monomer constituting the polymerizable monomer system and the toner property imparting agent such as a colorant used in the present invention include the following.

Examples of the polymerizable monomer include styrene monomers such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene and p-ethylstyrene, methyl acrylate, acrylic Ethyl acrylate, n-butyl acrylate, isobutyl acrylate, n-propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate and the like Acrylic esters, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, methacryl Phenyl, dimethylaminoethyl methacrylate, methacrylic acid esters such as ethyl methacrylate aminoethyl, other acrylonitrile, methacrylonitrile, and the like monomers acrylamide.

These monomers can be used alone or as a mixture. Among the above-mentioned monomers, it is preferable to use styrene or a styrene derivative alone or in a mixture with another monomer, from the viewpoint of the developing characteristics and durability of the toner.

In the present invention, polymerization may be carried out by adding a resin having a polar group to the monomer system. The polar resins that can be used in the present invention are exemplified below. (1) Examples of the cationic polymer include a polymer of a nitrogen-containing monomer such as dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate, and a copolymer with styrene, an unsaturated carboxylic acid ester, and the like. (2) Examples of the anionic polymer include nitrile monomers such as acrylonitrile, halogen-containing monomers such as vinyl chloride, unsaturated carboxylic acids such as acrylic acid and methacrylic acid,
Other examples include unsaturated dibasic acids / unsaturated dibasic acid anhydrides, polymers such as nitro monomers, and copolymers with styrene monomers. These polar resins are localized near the surface of the toner, thereby improving the blocking resistance of the toner.

As the coloring agent used in the present invention, known coloring agents can be used. For example, carbon black, iron black, C.I. I. Direct Red 1, C.I. I. Direct Red 4, C.I. I. Acid Red 1, C.I. I. Basic Red 1, C.I. I. Modan Red 30, C.I. I.
Direct Blue 1, C.I. I. Direct Blue 2,
C. I. Acid Blue 9, C.I. I. Acid Blue 1
5, C.I. I. Basic Blue 3, C.I. I. Basic Blue 5, C.I. I. Modern Blue 7, C.I. I. Direct Green 6, C.I. I. Basic Green 4, C.I.
I. Dyes such as Basic Green 6, graphite, cadmium yellow, mineral fast yellow, navel yellow, naphthol yellow S, Hanza yellow G, permanent yellow NCG, tartrazine lake, molybdenum orange, permanent orange GTR, benzidine orange G, cadmium red, Permanent red 4
R, Watching Red Calcium Salt, Brilliant Carmine 3B, Fast Violet B, Methyl Violet Lake, Navy Blue, Cobalt Blue, Alkaline Blue Lake, Victoria Blue Lake, Quinacridone, Rhodamine Lake, Phthalocyanine Blue, Fast Sky Blue, Pigment Green B, There are dyes such as Malachite Green Lake and Final Yellow Green G.
In the present invention, in order to obtain a toner using a polymerization method, it is necessary to pay attention to the polymerization inhibitory property and the aqueous phase migration property of the colorant, preferably, surface modification, for example, hydrophobicity by a substance without polymerization inhibition It is better to have a chemical treatment. In particular, attention must be paid to the use of dyes and carbon black since many of them have polymerization inhibitory properties. As a preferable method for surface-treating the dye system, there is a method in which a polymerizable monomer is polymerized in the presence of these dyes in advance, and the obtained colored polymer is added to the monomer system. In addition, regarding carbon black, in addition to the same treatment as the above-described dye, a graft treatment with a substance that reacts with the surface functional group of carbon black, for example, polyorganosiloxane or the like may be performed.

In the present invention, a magnetic substance may be added.
It is also preferable to use a material which has been subjected to a surface treatment such as a hydrophobic treatment with a substance which does not inhibit polymerization, like the colorant.

In the present invention, a wax generally used as a release agent such as a hydrocarbon compound is blended into the toner for the purpose of improving the releasability at the time of hot roll fixing.
As waxes used in the present invention, paraffin
Examples thereof include polyolefin-based waxes and modified products thereof, for example, oxides and grafted products, higher fatty acids and metal salts thereof, and amide waxes. These waxes have a softening point of 40 according to the ring and ball method (JIS K2531).
When the softening point is less than 40 ° C., the blocking resistance and shape retention of the toner tend to be insufficient, and when the softening point exceeds 130 ° C., the effect of the releasability is obtained. Tends to be insufficient. Generally, it is preferable to use 1.0 to 100 parts by weight of the release agent per 100 parts by weight of the polymerizable monomer.

In the present invention, it is preferable to add a charge control agent to the toner material in order to control the chargeability of the toner. As these charge control agents, among the known ones, those having almost no polymerization inhibitory and water phase transfer properties are used.For example, as positive charge control agents, nigrosine dyes, triphenylmethane dyes, quaternary ammonium salts, Examples include amine-based and polyamine-based compounds, and examples of the negative charge control agent include metal-containing salicylic acid-based compounds, metal-containing monoazo-based dye compounds, styrene-acrylic acid copolymers, and styrene-methacrylic acid copolymers. .

As the polymerization initiator, any suitable polymerization initiator such as 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1'-azobis (cyclohexane-1-
Azo or diazo polymerization initiators such as carbonitrile), 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile, benzoisoperoxide, methyl ethyl ketone peroxide, diisopropylperoxyca -Peroxide-based polymerization initiators such as carbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, and lauroyl peroxide. These polymerization initiators are preferably added in an amount of 0.5 to 20% by weight of the polymerizable monomer.

In the present invention, a crosslinking agent may be added.
5% by weight.

The additives used in the present invention for imparting various properties are selected from the viewpoint of durability when added to the toner.
The particle diameter is preferably 1/10 or less of the weight average diameter of the toner particles. The particle size of the additive means an average particle size obtained by observing the surface of the toner particles with an electron microscope. As additives for the purpose of imparting these properties, for example, the following are used.

1) Fluidity-imparting agents: metal oxides (such as silicon oxide, aluminum oxide, and titanium oxide), carbon black, and carbon fluoride. Those subjected to a hydrophobic treatment are more preferable.

2) Abrasives: metal oxides (such as strontium titanate, cerium oxide, aluminum oxide, magnesium oxide, and chromium oxide), nitrides (such as silicon nitride), carbides (such as silicon carbide), and metal salts (calcium sulfate) , Barium sulfate, calcium carbonate, etc.).

3) Lubricants: fluororesin powder (vinylidene fluoride, polytetrafluoroethylene, etc.), fatty acid metal salts (zinc stearate, calcium stearate, etc.).

4) Charge controllable particles: metal oxides (such as tin oxide, titanium oxide, zinc oxide, silicon oxide, and aluminum oxide), and carbon black.

These additives are used in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the toner particles.
0.1 to 5 parts by weight are used. These additives may be used alone or in combination of two or more.

The aqueous medium used in the present invention includes:
Eventually a suitable stabilizer is added. For example, as an inorganic compound, calcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide,
Examples include aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, and alumina. As the organic compound, polyvinyl alcohol, gelatin, methylcellulose, methylhydroxypropylcellulose, ethylcellulose, sodium salt of carboxymethylcellulose, polyacrylic acid and its salts, starch and the like can be used by dispersing them in an aqueous phase. This stabilizer is based on 100 parts by weight of the polymerizable monomer.
It is preferred to use 0.2 to 20 parts by weight.

In order to finely disperse these stabilizers, 0.001 to 0.1 parts by weight of a surfactant may be used. This is to promote the intended action of the dispersion stabilizer, and specific examples thereof include sodium dodecylbenzene sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate,
Examples include sodium oleate, sodium laurate, potassium stearate, calcium oleate and the like.

When an inorganic compound is used among these dispersion stabilizers, a commercially available one may be used as it is, but in order to obtain finer particles, the inorganic compound may be formed in an aqueous medium.

For example, in the case of calcium phosphate, an aqueous solution of sodium phosphate and an aqueous solution of calcium chloride may be mixed under high stirring.

The polymerized toner used in the present invention is obtained by the following method. That is, a monomer of the compound represented by the general formula in the polymerizable monomer, or the polymer, or the copolymer, a release agent, a colorant, a charge control agent, a polymerization initiator, and other additives And the monomer system uniformly dissolved or dispersed by a homogenizer, an ultrasonic disperser or the like is dispersed in an aqueous medium containing a dispersion stabilizer by an ordinary stirrer or a homomixer / homogenizer. Preferably, the monomer droplets have a desired toner particle size, typically 30
The granulation is performed by adjusting the stirring speed and time so as to have a particle size of μm or less. Thereafter, by the action of the dispersion stabilizer, the particles may be stirred to such an extent that the particle state is maintained and the particles are prevented from settling and floating. After completion of the reaction, while adding the aqueous medium to the suspension, the aqueous medium is distilled off to remove the dispersion stabilizer, and the generated toner particles are collected by washing and filtration.
dry. In the suspension polymerization method, the monomer system 100
It is preferable to use 300 to 3000 parts by weight of water as a dispersion medium with respect to parts by weight.

In the above step, the polymerization is carried out at a polymerization temperature of 40 ° C. or higher, generally 50 to 90 ° C. Further, the temperature may be raised in the latter half of the polymerization reaction.

The particle size distribution measurement in the present invention will be described.

As a measuring device, Coulter Counter T
A-II type (manufactured by Coulter), number average distribution,
Interface to output volume average distribution (made by Nikkaki)
And CX-1 personal computer (manufactured by Canon)
And the electrolyte is 1% N using 1st grade sodium chloride.
An aqueous aCl solution is prepared.

The measuring method is as follows.
In 50 ml, 0.1 to 5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant, and 0.5 to 50 mg of a measurement sample is further added.

The electrolyte in which the sample was suspended was subjected to a dispersion treatment for about 1 to 3 minutes using an ultrasonic disperser, and the particle size distribution of particles of 2 to 40 μm was measured using the Coulter Counter TA-II using a 100 μm aperture as an aperture. Is measured to obtain a volume average distribution and a number average distribution. A weight average particle diameter is obtained from the obtained volume average distribution and number average distribution.

Hereinafter, the present invention will be specifically described based on examples.

[0047]

Example 1 450 g of a 0.1 M Na ₃ PO ₄ aqueous solution was added to 710 g of ion-exchanged water and heated to 60 ° C., and then, using a TK homomixer (manufactured by Tokushu Kika Kogyo) at 12,000 rpm. And stirred. 68 g of 1.0 M CaCl ₂ aqueous solution
Was gradually added to obtain an aqueous medium containing Ca ₃ (PO ₄ ) ₂ .

Styrene 180 g 2-ethylhexyl acrylate 18 g C.I. I. Pigment Blue 15: 3 10 g Paraffin wax (sp. 70 ° C.) 60 g Monomer 1 2 g Di-tert-butylsalicylic acid metal compound 5 g Heat the above formulation to 60 ° C., and use a TK homomixer (Tokuki Kika Kogyo) Was uniformly dissolved and dispersed at 10,000 rpm. Into this, 10 g of a polymerization initiator 2,2'-azobis (2,4-dimethylvaleronitrile) and 1 g of dimethyl 2,2'-azobisisobutyrate were dissolved to prepare a polymerizable monomer system. The above-mentioned polymerizable monomer system was charged into the aqueous medium, and at 70 ° C. under an N ₂ atmosphere,
The mixture was stirred with a TK homomixer at 10,000 rpm for 20 minutes to granulate a polymerizable monomer system. Thereafter, the mixture was reacted at 70 ° C. for 4 hours while stirring with a paddle stirring blade, and then the liquid temperature was set to 80 ° C., and the reaction was performed for 5 hours.

After cooling, hydrochloric acid was added, and Ca ₃ (PO
₄ ) ₂ was dissolved, filtered, washed with water and dried to obtain a polymerized toner.

The particle diameter of the obtained toner is 8.
It had a very sharp particle size distribution at 0 μm.

BE per 100 parts by weight of the obtained toner
0.5 parts by weight of hydrophobic silica having a specific surface area of 200 m ² / g by the T method was externally added. To 5 parts by weight of this toner, 95 parts by weight of an acryl-coated ferrite carrier were mixed to prepare a developer.

Using this developer and external toner, a full-color copier CLC-500 modified by Canon was used to evaluate image formation in a low-temperature and low-humidity environment (15 ° C./10% RH). Even after the endurance of the sheet, a stable and good image was obtained without lowering the developability.

Example 2 A toner was prepared in the same manner as in Example 1 except that 10 g of a copolymer of styrene and monomer 2 (90:10, Mw 50,000) was used instead of monomer 1. Obtained.

The particle diameter of the obtained toner is 8.
At 5 μm, it had a very sharp particle size distribution. The developer was adjusted in the same manner as in Example 1, and the evaluation of image output was performed.
A stable and good image was obtained.

Example 3 In Example 1, C.I. I. Pigment Blue 15: 3
To C. I. Pigment Yellow 17 to obtain a polymerized toner in the same manner.

The particle diameter of the obtained toner is 8.
At 3 μm, it had a very sharp particle size distribution. The developer was adjusted in the same manner as in Example 1, and the evaluation of image output was performed.
A stable and good image was obtained.

Comparative Example 1 A polymerized toner was obtained in the same manner as in Example 1 except that the monomer 1 was not used.

The particle diameter of the obtained toner is 7.9 in weight average diameter.
It had a sharp particle size distribution at μm. The developer was adjusted in the same manner as in Example 1, and the image output was evaluated. As a result, after 20,000 sheets had been durable, the developability was lowered and a good image could not be obtained.

[0059]

As described above, the toner of the present invention has a very sharp particle size distribution, and the fluidity and chargeability of the toner are stable even under low humidity, and a good image can be stably obtained. .

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Makoto Kambayashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Kasugaya Valuable 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Kazuyuki Miyano 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-3-127707 (JP, A)

Claims (3)

(57) [Claims] A polymerization toner obtained by suspension-polymerizing a polymerizable monomer system in an aqueous medium, wherein a wax and a monomer represented by the following general formula are contained in the polymerizable monomer system. It contains a polymer of a monomer or a copolymer composed of the monomer and a vinyl monomer, and the wax has a softening point of 40.
To 130 ° C., a polymerization toner. General formula 2. The polymerization toner according to claim 1, wherein the content of the monomer represented by the general formula is 0.01 to 10% by weight of the total amount of the monomer. 3. The monomer represented by the above general formula,
Characterized in that it is any of monomers 1 to 3 shown
The polymerization method toner according to claim 1. Embedded image Monomer 1: Monomer 2: Monomer 3: