JPH0311468B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a toner for developing electrostatic images having stable positive charge characteristics. Conventionally, the electrostatic image developing method involves electrostatically attaching electrodetectable colored particles called toner to the electrostatic image, which are charged with a polarity opposite to the latent image charge of the electrostatic image. It is done. Such toner particles are, for example, particles with a size of about 1 to 30 microns, in which a colorant such as carbon black is dispersed in a binder resin such as styrene resin or acrylic resin. These toner particles are mixed with a carrier material such as iron powder or glass beads called a carrier in order to adhere to the electrostatic charge image, and a charge control agent is added so that triboelectric charging occurs to the opposite polarity. There is. Various materials have been developed for such charge control agents so that they can be controlled positively or negatively depending on the characteristics of the photoreceptor. For example, since a positive electrostatic latent image is formed on a photoreceptor made of selenium or the like, charge control is performed to impart negative polarity to the toner. Much research has been done on controlling this negative polarity, and in recent years, photoreceptors such as organic photoconductive photoreceptors and zinc oxide resin dispersion photoreceptors have attracted attention. In this photoreceptor, since the electrostatic latent image on the photoreceptor is negatively charged, the toner is required to have positive polarity. As charge control agents corresponding to such positive polarity, nigrosine dye is disclosed in Japanese Patent Publication No. 48-25669;
No. 51-11455 discloses dyes such as triphenylmethane dyes. However, these dyes have problems in moisture resistance and light resistance because they have ionized groups in their molecules. For this reason, JP-A No. 52-113739 discloses the use of a laked pigment of aminotriphenylmethane dye, but in order to make it into a pigment, it becomes insolubilized, the dispersibility becomes low, and the charge is not transferred into the particles. It becomes easier to exist uniformly,
Furthermore, there are disadvantages such as an increase in manufacturing steps and an increase in cost. Furthermore, when a dye is used as a charge control agent, although the dye itself can act as a coloring agent, the black tone of carbon black, for example, changes, the degree of blackening and tone adjustment deteriorate, and furthermore, in color toners, there is a substantial It becomes difficult to adjust the color tone. As described above, a satisfactory positive polarity toner has not been obtained so far. That is, an object of the present invention is to provide a toner with positive charge control without using a dye. Still another object is to provide a toner that does not change in color tone by using a substantially colorless or light-colored charge control agent. Still another object is to provide a toner that is stable and has a positive charge control, has excellent moisture resistance and light resistance, and is capable of forming high-quality images. The present invention is accomplished as follows. That is, this can be achieved by using an electrostatic photographic toner containing a compound of general formula () shown in the following formula. R ₁ is hydrogen, hydroxyl group, alkenyl group, or alkyl group, R ₂ is

【formula】

[Formula] or

[Formula] R ₃ to _{R 8} are hydrogen, an alkyl group, an allyl group, an aralkyl group, or an alkenyl group. The content of the compound in the binder resin is 0.8 to 5.
Contains % by weight. If the content is less than 0.8% by weight, the stability of the charge will be lost, and if the content is 5% by weight, the charge amount will be saturated, and even if it is added more than this, the effect will be small, and conversely, it will not be possible to use other electronic photographs. Adversely affects physical properties. Although the above-mentioned compounds are specifically shown, the invention is not limited to this example. The toner according to the present invention is usually produced by kneading and pulverizing methods, but as another method, a commonly used polymerization method may be used. As the binder resin used in the present invention,
Any conventionally known resin such as polystyrene resin, acrylic resin, epoxy resin, polyester resin, etc. can be used. The softening point of these binder resins is measured using a Koka type flow tester (manufactured by Shimadzu Corporation) and is usually within the range of 80 to 180°C. This value is determined from the viewpoints of toner crushability during production, blocking resistance during storage, fixability during image formation, etc. In the measurement of the softening point using the Koka type flow tester, a sample of 1 cm ³ (true specific gravity x weight of 1 cm ³ ) was placed in a cylinder with a cross section of 1 cm ² and a depth of 5 cm, which had a nozzle of 1 cm length and 1 mm diameter on the bottom. Inject, 80
Preheat at ℃ for 10 minutes, heat and melt under the pressure of a plunger with a load of 20 kg/cm while increasing the temperature by 6℃ per minute. The softening point is defined as the temperature at 1/2 of the height h of the S-shaped curve that is created when this is measured on a graph. Specific examples of resins include polystyrene, chloropolystyrene, poly-α-methylstyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, Styrene
Vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylic ester copolymer (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, Styrene-octyl acrylate copolymer, styrene-phenyl acrylate copolymer, etc.), styrene-methacrylate copolymer (styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer,
Styrene-butyl methacrylate copolymer, styrene-octyl methacrylate copolymer, styrene-
(phenyl methacrylate copolymer, etc.), styrene-α-methyl chloroacrylate copolymer, and styrene-acrylonitrile-acrylic acid ester copolymer. In addition, the epoxy resin has an epoxy equivalent of 900 to 3500, and particularly preferred ones include Epicote 1004, Epicote 1007, Epicote 1009 (manufactured by Ciel Chemical Co., Ltd.), and Araldite.
Examples include GY6084, Araldite GY6099 (manufactured by Ciba Geigy), etc. The polyester resin is a polycondensation consisting of a polyhydric alcohol and a polybasic acid, and preferred polyhydric alcohol components include ethylene glycol, glycerin 1,2-propylene glycol, 1,3-propylene glycol, neopentyl glycol, 1,4-butanediol, 1,6
-Hexanediol, 1,4-cyclohexanedimethanol, trimethylolethane, trimethylolpropane, pentaerythritol, etc. are used, and the polybasic acid components include maleic acid, fumaric acid, isophthalic residue, terephthalic acid, adipic acid, and sebacin. Acid, trimellitic acid, pyromellitic acid, etc. can be used. In addition, the above resin is
They can be used alone or in combination of two or more. Since the charge control agent of the present invention is colorless or light-colored, the toner of the present invention can be given desired coloring by using a conventionally known colorant. For example, black toner includes colorants such as carbon black, aniline black, lamp black, oil black, azo oil black, and magnetic powder such as triiron tetroxide.Furthermore, colorants for color toner include blue toner: Copper phthalocyanine, sulfonamide derivative dyes, aniline blue, calco oil blue, ultramarine blue, etc. Yellow toner: benzidine derivatives such as diazo yellow, chrome yellow, quinoline yellow, etc. Red toner: Rose Bengal, Dupont Oil Red, Polytang Examples include rhodamine B lake, which is a double salt of stric acid, molybdic acid and xanthene dye, carmine 6B, and quinacridone derivatives, but it goes without saying that any commonly used coloring agent can be used. The amount of the colorant used in the toner of the present invention is adjusted so as to obtain the desired color tone and density, but generally 1 to 20 parts by weight are added to the toner. When the toner of the present invention is used in a roller fixing method (particularly a hot roller fixing method), a release agent may be added to prevent offset. Various types of release agents are known, and the most preferred is an olefin polymer. This olefin polymer is an olefin polymer containing only olefin as a monomer component or an olefin copolymer containing a monomer other than olefin as a monomer component, and has a low softening point. Examples of olefins as monomer components include ethylene, propylene, butene-1, pentene-1, and hexene-1.
1, heptene-1, octene-1, nonene-1,
Decene-1 or its homologues with different positions of the unsaturated bond or e.g. 3-methyl-1-
All kinds of olefins such as butene, 3-methyl-2-pentene, 3-propyl-5-methyl-2-hexene, etc. into which an alkyl group is introduced as a branching group are included. In addition, monomers other than olefin that form a copolymer with olefin include, for example, vinyl methyl ether, vinyl-
Vinyl ethers such as n-butyl ether and vinyl phenyl ether; vinyl esters such as vinyl acetate and vinyl butyrate; haloolefins such as vinyl fluoride, vinylidene fluoride, tetrafluoroethylene, vinyl chloride, vinylidene chloride, and tetrachloroethylene; For example, methyl acrylate, ethyl acrylate, n-butyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, stearyl methacrylate, N,N-dimethylaminoethyl methacrylate, t-butylaminoethyl methacrylate, etc. acrylic esters or methacrylic esters; for example, organic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, and itaconic acid; various examples include diethyl fumarate and β-pinene. The olefin polymer used in the present invention is an olefin polymer consisting only of olefins containing at least two or more of the above-mentioned olefins as monomer components, such as ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-butene copolymer, At least one type of pentene copolymer, propylene-butene copolymer, propylene-pentene copolymer, ethylene-3-methyl-1-butene copolymer, ethylene-propylene-butene copolymer, etc., or the above-mentioned olefins. and at least one monomer other than olefin as described above, such as ethylene-vinyl acetate copolymer, ethylene-vinyl methyl ether copolymer, ethylene-vinyl chloride Copolymer, ethylene-methyl acrylate copolymer, ethylene-methyl methacrylate copolymer, ethylene-acrylic acid copolymer, propylene-vinyl acetate copolymer, propylene-
Vinyl ethyl ether copolymer, propylene-ethyl acrylate copolymer, propylene-methacrylic acid copolymer, butene-vinylmethyl methacrylate copolymer, pentene-vinyl acetate copolymer, hexene-vinyl butyrate copolymer , ethylene-propylene-vinyl acetate copolymer, ethylene-vinyl acetate-vinyl methyl ether copolymer, and the like. Among the olefin polymers used in the present invention, in those containing monomers other than olefin as monomer components, it is desirable that the olefin component contained in the copolymer be as large as possible. This is because, in general, as the content of the olefin component decreases, the mold releasability decreases, and the properties such as fluidity and image quality of the toner tend to deteriorate. Therefore, it is desirable that the content of the olefin component in the copolymer be as high as possible, and in particular, copolymers containing about 50 mol% or more of the olefin component are effectively used in the present invention. Preferably, the olefin polymer has a softening point of 100° to 180°C, particularly 130° to 160°C. The amount of the olefin polymer used is 1 to 20 parts by weight, preferably 3 to 15 parts by weight, per 100 parts by weight of the resin component of the toner, and if it is less than 1 part by weight, it may not have a sufficient offset prevention effect.
Moreover, if it exceeds 20 parts by weight, it adversely affects other electrophotographic physical properties, which is not preferable. When the toner of the present invention is used as a one-component developer, any magnetic material can be added. Any acidic, neutral, or basic magnetic material can be used as this magnetic material, but the pH is 4 or more, preferably 5 to 5.
10 magnetic material is good. The magnetic substance used in the present invention is a substance that is strongly magnetized in the direction of a magnetic field, is preferably black in color, is well dispersed in the resin, is chemically stable, and has a particle size of A material that can be easily obtained in the form of fine particles of 1 μm or less is desirable, and magnetite (triiron tetroxide) is the most preferred. Typical magnetic or magnetizable materials include metals such as cobalt, iron, and nickel; aluminum, cobalt, lead, iron, copper, magnesium, nickel, tin, zinc, antimony,
Beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten,
Alloys of metals and mixtures thereof such as vanadium; metal compounds including metal oxides such as aluminum oxide, iron oxide, copper oxide, nickel oxide, zinc oxide, titanium oxide and magnesium oxide; Refractory titanides such as; carbides such as tungsten carbide and silica carbide; ferrites and mixtures thereof, etc. may be used. These ferromagnetic materials preferably have an average particle size of about 0.1 to 1 μm, and when included in the toner, 30 parts by weight of the binder resin component is used.
The amount is preferably 300 parts by weight, particularly preferably 50 to 200 parts by weight per 100 parts by weight of the resin component. In the toner of the present invention, a polymer resin is obtained by polymerizing monomers constituting the binder resin by emulsion polymerization, suspension polymerization, solution polymerization, etc., and a colorant (usually, Carbon black) is mixed in an amount of 3 to 20% by weight, heated and melted, kneaded, cooled, crushed and dispersed to obtain a particle size of 1 to 50μ, preferably 5 to 30μ.
toner. If the particle size is less than 1μ, it will cause fogging, and if it exceeds 50μ, it will cause uneven image quality. In addition, the monomer of the binder resin is combined with a polymerization initiator (lauroyl peroxide, benzoyl peroxide, 2,2'-azobisisobutyronitrile, etc.),
Colored polymer particles may be obtained by dispersion and suspension polymerization in a hydrogen medium with the addition of a coloring agent, and then formed into a toner. In order to form an image using the toner of the present invention by electrophotography, for example, a photosensitive layer containing an inorganic photoconductive material such as zinc oxide, lead oxide, or mercury sulfide dispersed in a binder resin is used. A photoreceptor provided on a conductive support, or a photoreceptor provided on a conductive support with a photosensitive layer containing an organic photoconductive material such as anthracene or polyvinylcarbazole in a binder resin as necessary. used. The surface of the photosensitive layer of such a photoreceptor is entirely charged by corona discharge using, for example, a corotron or scorotron charger, and then imagewise exposed to light or the like to form an electrostatic charge image. Next, when this electrostatic charge image is used as a two-component developer, for example, by a cascade method or a magnetic brush method,
A toner image is formed by developing with a developer comprising a mixture of the toner of the present invention and a glass beads or iron powder carrier. In the case of a one-component developer, the carrier is not required. This toner image is transferred onto the transfer paper by being pressed against the transfer paper under, for example, corona discharge. The toner image transferred onto the transfer paper is heat-fixed by a heat roll fixing device coated with, for example, a fluorine-based resin or silicone rubber having mold-releasing properties. The invention will now be illustrated by examples. In addition, "parts" shown in the following examples indicate "parts by weight" unless otherwise specified. Example 1 100 parts of styrene/butyl acrylate copolymer (composition ratio: 85:15) (softening point: 125°C), 10 parts of Mitsubishi Carbon Black #30 (manufactured by Mitsubishi Chemical Industries, Ltd.), Viscoel 550P (low molecular weight) Polypropylene (manufactured by Sanyo Chemical Industries, Ltd.) (6 parts) and Exemplified Compound (1) (3 parts) were thoroughly melted and kneaded in a kneader, cooled, coarsely crushed in a hammer mill, further finely crushed in a jet mill, and then finely crushed in a classifier to obtain an average particle size. The particles with a diameter of 15μ were classified and used as toner. This is referred to as "toner 1". Using a developer consisting of 2 parts of this toner and 100 parts of iron powder carrier, a copying machine using an organic photoconductive photoreceptor was modified from Ubix V (manufactured by Konishiroku Photo Industry Co., Ltd.). We conducted 10,000 image tests. The obtained toner image had no fog, was clear, had a high degree of blackening, and had good fixing properties such as prevention of offset. Example 2 A toner was obtained in the same manner as in Example 1 except that Exemplified Compound (2) was used instead of Exemplified Compound (1). This will be referred to as "toner 2". When the image was evaluated in the same manner as in Example 1, a clear image with an excellent degree of blackening was obtained. Example 3 A toner was obtained in the same manner as in Example 1 except that Exemplified Compound (4) was used instead of Exemplified Compound (1). This toner will be referred to as "Toner 3." Similar to Example 1,
When the image was evaluated, a clear, fog-free image with an excellent degree of blackening was obtained. Example 4 A toner was obtained in the same manner as in Example 1, except that exemplified compound (6) was used instead of exemplified compound (1). This toner will be referred to as "Toner 4". When the image was evaluated in the same manner as in Example 1, it was found that the image was clear and had a high degree of blackening.
An image with good color tone was obtained. Example 5 A toner was obtained in the same manner as in Example (1) except that Exemplified Compound 12 was used instead of Exemplified Compound (1). This toner will be referred to as "Toner 5." When the image was evaluated in the same manner as in Example 1, a good image was obtained that was clear, had an excellent degree of blackening, and was free from fog. Example 6 In Example 1, except that 5 parts of exemplified compound (1) was used,
A toner was obtained in the same manner. This toner will be referred to as "Toner 6". When the image was evaluated in the same manner as in Example 1, a clear, fog-free image with excellent color tone was obtained. Example 7 A toner was obtained in the same manner as in Example 1 except that 0.8 part of the exemplified compound was used. When the image was evaluated in the same manner as in Example 1, a clear image with excellent color tone and no fog was obtained. Comparative Example 1 A toner was obtained in the same manner as in Example 1, except that the following crystal violet dye was used instead of Exemplified Compound (1). Use this toner as “Comparison Toner 1”
shall be. When image evaluation was performed using this toner, an image with a changed color tone and lack of clarity was obtained. Comparative Example 2 A toner was obtained in the same manner as in Example 1 except that Varifast dye was used instead of Exemplified Compound (1). This toner is referred to as "comparison toner 2." When image evaluation was performed using this toner, an image with a changed color tone and lack of clarity was obtained. Example 8 When image evaluation was performed in a high temperature and high humidity condition using the above "Toner 1" to "Toner 7" and "Comparative Toner 1" and "Comparative Toner 2", it was found that "Toner 1"
~ With "Toner 7", a stable, clear and fog-free image was obtained, but with "Comparative Toner 1" and "Comparative Toner 2", fogging occurred and the degree of blackening decreased. "Toner 1", "Toner 2" and "Comparison Toner 1"
Figure 1 shows the change in the amount of charge under high temperature and high humidity conditions. As described above, "Toner 1" and "Toner 2" show stable charging, but "Comparative Toner 1" shows that attenuation occurs.

[Brief explanation of the drawing]

"Toner 1""Toner2" and "Comparison Toner 1"
Graph of changes in charge amount under high temperature and high humidity conditions.

Claims (1)

[Scope of Claims] 1. A positively charged electrostatic developing toner, wherein the binder resin contains at least 0.8 to 5% by weight of a binder resin, a colorant, and a compound represented by the following general formula. R ₁ is hydrogen, a hydroxyl group, an alkyl group, or an alkenyl group, and R ₂ is [Formula] [Formula] or [Formula] R ₃ to _{R 8} are hydrogen, an alkyl group, an allyl group, an aralkyl group, or an alkenyl group.