JPH0367266B2 - - Google Patents

Description

[Detailed description of the invention]

[Field of Application of the Invention] The present invention relates to a charge imparting member having an improved function for imparting charge to toner used for developing electrostatic images in electrophotography, electrostatic recording, electrostatic printing, and the like. [Background of the invention] Conventional electrophotographic methods include U.S. Patent No. 2297691;
Various methods are described in Japanese Patent Publication No. 42-23910, Japanese Patent Publication No. 43-24748, etc.
They essentially provide a uniform electrostatic charge on a photoconductive insulator layer, form an electrostatic latent image by irradiating the insulator layer with a light image, and then apply the latent image using the technique. After developing and visualizing it with a fine powder called toner and transferring the powder image to paper etc. as necessary,
Fixing is performed using heat, pressure, solvent vapor, or the like. The developing methods applied to these electrophotographic methods can be roughly divided into dry developing methods and wet developing methods. The former is further divided into methods using a two-component developer and methods using a one-component developer.
Two-component developing methods include a magnetic brush method using an iron powder carrier, a cascade method using a bead carrier, a fur brush method using fur, etc., depending on the type of carrier for conveying the toner. Examples of one-component development methods include the powder cloud method, in which toner particles are sprayed, and the contact development method, in which toner particles are brought into direct contact with the electrostatic latent image surface (contact development, or toner development method). (also referred to as development), a jumping development method in which toner particles are not brought into direct contact with the electrostatic latent image surface, but are charged and flown toward the latent image surface by the electric field of the electrostatic latent image; magnetic conductivity; There is the MagneDry method, which develops by bringing toner into contact with the electrostatic latent image surface. As toners applied to these 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. In addition, as magnetic toner,
In place of or in addition to the above dyes or pigments, materials containing magnetic particles such as magnetite are used. In the case of a system using a so-called two-component developer, the above toner is usually mixed with carrier particles such as glass beads and iron powder. Further, the toner is given a positive or negative charge in advance depending on the polarity of the electrostatic latent image to be developed. In order to charge the toner, it is also possible to use only the triboelectricity of the resin, which is a component of the toner, but with this method, the toner's chargeability is small, so the image obtained by development is prone to fogging. ,
It becomes unclear. Therefore, in order to impart desired triboelectric charging properties to the toner, charge control agents such as dyes and pigments that enhance the charging properties are added. However, in order to impart chargeability to the toner by adding these additives, these additives must be exposed to some extent on the toner surface. Therefore, due to friction between the toners, collision with the carrier, friction with the electrostatic latent image carrier, etc., these additives fall off the toner surface, contaminating the carrier, etc., and damaging the electrostatic latent image carrier, such as the photoreceptor. Contamination of belts, drums, etc. may occur. As a result, charging properties deteriorate, and as development work is repeated, deterioration progresses.
Practical problems include a decrease in image density, a decrease in fine line reproducibility, and an increase in fog. The above-mentioned problems can be improved by improving the affinity and dispersibility of the toner binder with additives such as dyes and pigments that impart chargeability or charge control agents. Surface treatment to increase toner properties often results in a decrease in chargeability, and if the toner is mechanically sheared strongly and dispersed finely, the proportion of additives that appear on the toner surface decreases, and sufficient chargeability is not imparted. It becomes a trend.
For these reasons, the number of additives that can impart chargeability to toner to a practically satisfactory level is extremely limited, and only a small number of them have been put to practical use. In particular, in order to obtain not only black and white images but also color images, it is preferable that the charge control agent added to the toner be colorless, and in this case, there are almost no practically satisfactory charge control agents. In view of these circumstances, we aim to improve the charge imparting properties to toner not only by using toner additives, but also by improving the conveyance, regulation, and friction of carriers, sleeves, doctor blades, etc. that come into contact with toner during the development process. A member (hereinafter collectively referred to as a "charge-imparting material") that comes into contact with the toner during or prior to the development process to impart the necessary charge to the toner for development, or to provide an auxiliary charge to the toner. It has also been proposed to improve the charge imparting characteristics to toner by using materials (hereinafter collectively referred to as materials or members). This method of actively imparting a charge to the toner using a charge imparting material almost eliminates the need for the toner to contain additives to improve its charging properties, thus providing an essential improvement over the above-mentioned problems. can be measured. For example, the causes of contamination of carrier particles, photoreceptors, etc. are essentially reduced, and therefore charging performance is reduced due to repeated development operations.
It does not disturb the latent image. Furthermore, the color toner can be easily charged without impairing its color tone. However, charge-imparting materials such as carriers, sleeves, and doctor blades must not only have strong charge-imparting ability but also be durable and able to withstand friction with toner. For example, it is desired that the carrier be used for a long period of time without replacement, and the sleeve is required to have the same level of durability as the main body of the developing machine. [Object of the Invention] The present invention has been made in order to provide a charge imparting material that solves the above-mentioned problems, and its purpose is to provide a charge imparting material that imparts an appropriate negative charge to toner. There is a particular thing. A further object of the present invention is to provide a charge imparting material whose performance does not deteriorate even after long-term use. A further object of the present invention is to provide a charge-imparting material that provides images with excellent fine line reproducibility and gradation. A further object of the present invention is to provide a charge imparting material suitable for charging color toners. [Summary of the Invention] [Summary of the Invention] The present invention provides a charge imparting material for developing an electrostatic image for imparting a negative triboelectric charge to a toner, using a 1,3,5-triazine represented by the following chemical structural formula. derivative [In the formula, R ₁ represents a hydrogen atom, an alkyl group, or an alkoxy group, and R ₂ and R ₃ represent a hydrogen atom or

[Formula] may be the same or different. ] The present invention relates to an electrostatic image development imparting material having at least on the surface thereof. Typical specific examples of compounds used in the charge-imparting material of the present invention include the following compounds (1) to (3). Various methods for synthesizing triazines are known, for example, J.Am.Chem.Soc., 76 , 632;
(1954); J.Chem.Soc., 1947 , 154; CA, 43,
238 (1949); C, A., 45 , 2513, (1951); J.Org.
Chem., 17 , 1162 (1952); Chem.Ber., 87 , 1865
(1954); Science, 121, 61 (1955), etc. For example, the compound example (1) is cyanuric chloride and p-
Synthesized by reaction with toluidine. The above compound generally has an average particle size of 10 to 0.01 μm, particularly 2 μm, although it depends on the form of the charge imparting material to be applied.
It is preferable to form the charge imparting material in the form of particles of ~0.1 μm. These compounds can be applied by dipping, spraying, brushing, etc. to the base material of the charge-imparting material with a coating solution obtained by dissolving or dispersing them in a solvent or dispersion medium together with a binder resin if necessary. When the base material is in the form of carrier particles, the carrier particles can be coated onto the base material by immersion mixing with the above-mentioned coating liquid and then drying, or by coating with a fluidized bed of a direct mixture of this and the above-mentioned compound. The charge imparting material of the present invention can be obtained by forming a coating layer of the compound. Alternatively, the charge imparting material may be directly melted and kneaded with a binder resin and extruded and laminated onto a base material to obtain a charge imparting material having a coating layer containing the material. Furthermore, these compounds may be incorporated into a moldable resin and molded into the shape of carrier particles, sleeves or doctor blades to provide a charge-imparting material. Common binder resins or molding resins can be used. For example, polystyrene, polyacrylic ester, polymethacrylic ester, polyacrylonitrile, rubber resins such as isoprene and butadiene, polyester, polyurethane, polyamide, epoxy resin,
Rosin, polycarbonate, phenolic resin, chlorinated paraffin, polyethylene, polypropylene, silicone resin, Teflon, derivatives thereof, copolymers thereof, or mixtures thereof can be used. After coating or molding, these resins can be made to have a crosslinked structure as necessary to improve the durability of the surface layer of the charge-imparting material. When a binder resin or a molding resin is used, it is preferable to use the compound in a ratio of 0.5 to 200 parts, particularly 2 to 100 parts, based on 100 parts by weight (the same applies hereinafter). When coating the surface of the charge-imparting material, it is necessary to appropriately control the coating or coating amount of the compound, but the amount of the material is preferably in the range of 0.01 to 10 mg/ ^cm2 , preferably 0.1 to ² mg/cm2. good. In addition to the above-mentioned compounds, ceramic powders such as silica powder, aluminum oxide, cerium oxide, and silicon carbide may also be used as fillers in the series of cases described above. Furthermore, a conductivity imparting agent such as carbon black or tin oxide may be used to adjust the conductivity. Further, in order to prevent the spent toner from accumulating on the sleeve or carrier surface, a release agent such as a fatty acid metal salt, vinylidene fluoride, etc. may be used. All known carriers can be used as the base material of the carrier-type charge imparting material, and include metals or alloys such as iron, nickel, aluminum, and copper, powders or particles of metal compounds containing metal oxides, and is glass, SiC, BaTiO ₂ ,
Ceramic powder or particles such as SrTiO ₂ are used. Further, examples include those whose surfaces have been treated with a resin, resin powder, or resin powder containing a magnetic substance. The average particle size is preferably about 20 to 250μ. Furthermore, the base material of the charge imparting material in the form of a sleeve or doctor blade may be metals or alloys such as iron, aluminum, stainless steel, or nickel, or non-metallic compounds such as ceramics or plastics, which can generally be used as a sleeve or doctor blade. can be used. On the other hand, as toners to be used in combination with the charge imparting material of the present invention as described above, substantially all toners that have been used as conventional toners for developing electrostatic images can be effectively used. That is, both non-magnetic and magnetic toners can be used. More specifically, the toner is a colored fine particle containing a colorant in a binder resin, and may contain magnetic powder if necessary. Furthermore, these toners may contain small amounts of charge-imparting substances, such as dyes, pigments, or so-called charge control agents, in order to impart a more effective charge, and may also contain fluidizing agents such as colloidal silica, It may also contain abrasives such as cerium oxide, strontium titanate, and silicon carbide, and lubricants such as metal stearate and vinylidene fluoride. It may also contain conductivity imparting agents such as carbon black and tin oxide. As the developing method using the charge imparting material and toner of the present invention described above, substantially all developing methods using a two-component developer or a single-component developer can be used. For example, magnetic brush development method, cascade development method, fur brush development method, so-called microtoning development method using magnetic substance-containing resin powder as a carrier, development method using resin powder as a carrier, so-called jumping development method, or non-magnetic toner. This is a jumping development method. [Effects of the Invention] As described above, according to the present invention, a charge imparting material for imparting a charge to a toner for developing an electrostatic image having a compound having a specific structure as a charge control agent present on the surface is provided. provided. In particular, as shown in the examples below, the compound of the present invention not only has excellent charge control properties and stability against heating and moisture absorption, but also has the ability to be coated or kneaded onto the surface of a charge-imparting material. When present by dispersion or the like, a good charge imparting material with excellent friction durability with toner can be provided. Therefore, by using this charge-imparting material, it is possible to obtain a substantial improvement over the various problems that occur when the charge-imparting material is mixed only into toner to improve its charging characteristics. [Examples of the Invention] Example 1 and Comparative Example 100 g of the above compound (1) was dissolved and dispersed in 1 methyl ethyl ketone (MEK), 1 kg of iron carrier (particle size: 250 to 400 mesh) was dispersed therein, and the mixture was heated in a ball mill to approx. Stir for 30 minutes. After drying this iron powder carrier mixture to completely remove the solvent, light agglomerations were loosened to obtain a carrier-like charge imparting material according to the present invention. In addition, in order to compare with the product of the present invention, a comparative product carrier was prepared without adding compound (1) in the above procedure. Separately, a toner was prepared according to the following formulation without adding any charge control agent. Styrene (product name D-125: manufactured by Etsuso Chemical Co., Ltd.)
100 parts by weight Carbon black (trade name Raven 3500, manufactured by Kayabot Co., Ltd.) 6 parts by weight The above materials were kneaded, crushed, and classified to a particle size of 1 to 100 parts by weight.
The thickness was adjusted to 30μm. The weight ratio of this toner and each of the above carriers is 10:
100% and used as a developer. The amount of triboelectric charge of these developers was measured by the blow-off method and was as follows. Invention product (Example 1) -11μC/g Comparative product -2μC/g Using these developers, Canon NP-5000
When images were produced using a copying machine, the product of the present invention showed no change in image density even after a durability test of 50,000 sheets, had good fine line reproducibility, and had good gradation.
There was also no fogging. On the other hand, the comparative product
Changes in image density occurred after 3000 sheets. Example 2 A carrier-like electrification material was prepared in the same manner as in Example 1 except that compound (5) was used instead of compound (1), and a developer was further prepared in the same manner as in Example 1. . The triboelectric charge amount of the toner in the obtained developer was -9 μC/g. Example 3 100 g of polymethyl methacrylate resin was dissolved in xylene 1, and 50 g of compound (6) was further mixed therein. This was mixed with the same iron powder carrier as in Example 1 and dried to obtain a carrier with an electrification effect. When this was used and combined with a toner in the same manner as in Example 1, the triboelectric charge amount of the toner was -12 μC/g.

Claims (1)

[Claims] 1. A charge imparting material for electrostatic image development for imparting a negative triboelectric charge to a toner, a 1,3,5-triazine derivative represented by the following chemical structural formula: [In the formula, R ₁ represents a hydrogen atom, an alkyl group, or an alkoxy group, and R ₂ and R ₃ represent a hydrogen atom or [Formula], and may be the same or different. ] An electrostatic charge image development imparting material having at least the following on its surface. 2. The charge imparting material for developing electrostatic images as set forth in claim 1, wherein the charge imparting material is carrier particles. 3. The charge imparting material for developing an electrostatic image as set forth in claim 1, wherein the charge imparting material is a cylindrical sleeve. 4. The charge imparting material for developing an electrostatic image as set forth in claim 1, wherein the charge imparting material is a doctor blade.