JPH0421862B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a cyan toner used in color electrophotography. More specifically, the developed image has extremely good spectral reflection characteristics, and the durability of the developer has been improved, resulting in extremely clear images with no blurring in the background during color electrophotographic copying of multiple sheets. The present invention provides a cyan toner composition for color electrophotography from which color copies can be obtained. Conventionally, electrophotographic methods have been described in various publications such as US Pat. Electrophotography generally uses a photoconductive substance to form an electrical latent image on a photoreceptor by various means, then develops the latent image with toner and, if necessary, forms a powder image on paper or the like. After being transferred, it is fixed by heating, pressure, solvent vapor, or the like. In addition, in order to obtain a multicolor image, the original is exposed using a color separation filter, and the above process is repeated multiple times using color toners such as yellow, magenta, and cyan, and the toner images are superimposed to form a color image. It is something. Furthermore, toner for developing electrical latent images has conventionally been produced by finely pulverizing particles of approximately 1 to 30 μm in size, in which a coloring agent (dye and pigment such as carbon black) is dispersed in a binder resin such as polystyrene. was used as a toner. Such toners are commonly mixed with carrier materials such as glass beads, iron powder, and fur and used to develop latent electrical images. These toners require different physical and chemical properties. However, many of the known toners have several deficiencies as described below. That is, many toners that readily melt upon heating tend to cake or clump during handling and storage. The triboelectric and rheological properties of many toners are adversely affected by changes in environmental humidity. In addition, with many toners, toner particles and carrier particles collide with each other due to repeated development through continuous use and their contact with the photosensitive plate surface.
Mutual deterioration of the carrier particles and photosensitive plate changes the density of the resulting image or increases the background density, reducing the quality of the copies. Furthermore, with many toners, when an attempt is made to increase the density of a copied image by increasing the amount of toner adhering to the surface of a photosensitive plate having a latent image, the background density usually increases, resulting in a so-called fog phenomenon. Many of the known toners have one or more of the above defects, and there is a continuing need for improved toners. Furthermore, color electrophotographic toners need to overcome the above-mentioned defects and have excellent physical and chemical properties. The conditions must also be met. (1) The toner must be highly transparent in order to layer multiple colors. (2) Each toner must have excellent melt compatibility. (3) Good spectral reflection characteristics to faithfully reproduce the original. Moreover, in color electrophotographic toners, colorants are What is necessary is that the combination of toner and binder resin allows the toner to be selectively charged positively or negatively to a suitable carrier. This is not very easy considering the various conditions that color electrophotographic toners must satisfy. Therefore, the combination of colorant and binder resin is extremely important. In short, an object of the present invention is to provide a cyan toner for color electrophotography using a novel combination of a colorant and a binder resin, which overcomes the above-mentioned defects of the toner and also satisfies the requirements for a toner for color electrophotography. There is a particular thing. A first object of the present invention is to provide a cyan toner for color electrophotography with very good spectral reflection characteristics and high transparency. The second object of the present invention is yellow, magenta,
To provide a cyan toner for color electrophotography that exhibits an intense black color by superimposing three cyan colors. A third object of the present invention is to provide a color electrophotographic cyan toner that can be melted and fixed more quickly with lower thermal energy. A fourth object of the present invention is to provide a color electrophotographic toner that is resistant to agglomeration. A fifth object of the present invention is to provide a color electrophotographic cyan toner having stable flow properties and triboelectric properties under varying humidity conditions. A sixth object of the present invention is to provide a cyan toner for color electrophotography, in which the density of the resulting copied images is constant and the quality of the copies does not deteriorate during continuous copying through repeated development. That is, in the present invention, a polyester resin consisting of an aliphatic acid, an aromatic acid, and a bisphenol alcohol is used as a binder resin, and the temperature at which the melt viscosity of the polyester resin shows 10 ⁵ cp is T ₁ , and 0.5 × 10 The temperature when it shows ⁵ cp
When T ₂ , the following conditions T ₁ = 100 to 150℃, ｜△T｜=｜T ₁ −T ₂ ｜=10
~30℃, the polyester resin satisfies
A cyan toner for color electrophotography, characterized in that it contains a blue organic pigment represented by the following general formula [] in an amount of 0.5 to 10% by weight based on a binder resin. General formula [] [X ₁ to ₄ are

【formula】

[Formula] or -H (in the formula, R and R' represent an alkylene group having 1 to 5 carbon atoms),
However, the number of hydrogen atoms in X ₁ to _{X 4} is 0, 1, 2, or 3. ]Regarding. The reason why this range is a preferable range is that, for example, resins with T ₁ of less than 100°C easily block and have shortcomings in storage stability.
If T ₁ exceeds 150° _C , color mixing properties will be poor and fixing properties will also be difficult;
For example, there is a temperature at which moderate color mixing occurs for resins such as |ΔT| = 50°C, but if that temperature is too high, or if the clear If a certain color tone cannot be reproduced, or if the temperature is low, the glass transition temperature of the toner becomes low, causing problems such as blocking. The toner of the present invention may further contain a charge control agent, if necessary. For example, when used as a negative toner, a metal chelate of alkyl salicylic acid can be used, and when used as a positive toner, a dimethylaminoethyl methacrylate-styrene copolymer can be used. Further, for the developer in which the toner of the present invention is used, a fluidity modifier such as colloidal silica is added to the toner in an amount of 0.01% to 5% by weight, preferably 0.1% to 2% by weight.
It may be added to some extent. The constituent components of the toner of the present invention will be explained below. Specific examples of the blue colorant in the toner of the present invention include: can be mentioned. These colorants are different from the binder resin.
Adding 1 to 10% by weight gives the toner very good spectral reflection properties. If the amount added is less than 1% by weight, the coloring ability will be poor, and if it is more than 10% by weight, the coloring power will be sufficient, but charge controllability will become a problem. These coloring agents can be synthesized by directly reacting potassium phthalimide with a copper-phthalocyanine chloromethyl derivative synthesized from 4-chloromethylphthalodinitrile in the case of the above-mentioned compound example (a). The polyester resin used in the toner of the present invention is synthesized from an aliphatic acid, an aromatic acid, and a bisphenolic alcohol. Preferred aliphatic acids include, for example, succinic acid,
Adipic acid, fumaric acid, maleic acid, sebacic acid, glutaric acid, etc. are used, and examples of preferable aromatic acids include phthalic acid, isophthalic acid, terephthalic acid, and acid anhydrides thereof. Further, as a preferable bisphenol alcohol, 2,2-bis(4-hydroxyphenyl)
Propane, 2,2-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)methane, 4,4'-dihydroxydiphenyl ether, etc. are used. Examples of polyester resins that can be preferably used in the present invention are shown below. (1) Polyester resin (A) Succinic acid 3.0 mol Terephthalic acid 2.0 mol 2,2-bis(4-hydroxyphenyl)propane 5.0 mol T ₁ = 128℃ T ₂ = 140℃ | ΔT | = 12℃ Here, T ₁ has a polyester melt viscosity of 10 ⁵ cp
T ₂ is the temperature at which the melt viscosity of the polyester is 0.5×10 ⁵ cp, and |ΔT| is |T ₁ −T ₂ |. (2) Polyester resin (B) Adipic acid 2.5 mol Isophthalic acid 3.0 mol 2,2-bis(4-hydroxyphenyl)propane 5.0 mol T ₁ = 139℃ T ₂ = 150℃ | ΔT | = 11℃ (3) Polyester resin (C) Fumaric acid 2.0 mol Terephthalic acid 3.0 mol 2,2-bis(4-hydroxyphenyl)ethane 5.0 mol T ₁ = 115℃ T ₂ = 130℃ | ΔT | = 15℃ (4) Polyester resin ( D) Sebacic acid 1.5 mol Isophthalic acid 3.5 mol 2,2-bis(4-hydroxyphenyl)methane 5.5 mol T ₁ = 108℃ T ₂ = 125℃ |ΔT|=17℃ (5) Polyester resin (E) Maron Acid 2.5 mol Phthalic acid 3.0 mol 2,2-bis(4-hydroxyphenyl)propane 5.0 mol T ₁ = 121℃ T ₂ = 130℃ ｜ΔT｜=9℃ (6) Polyester resin (F) Glutaric acid 2.5 mol Isophthalic acid Acid 3.0 moles 2,2-bis(4-hydroxyphenyl)propane 5.0 moles T ₁ = 130℃ T ₂ = 148℃ |ΔT| = 18℃ From these aliphatic acids, aromatic acids, and bisphenolic alcohols The polyester resin has excellent transparency and photoselectivity, and is especially suitable for use as a color electrophotographic toner in which multiple transfers are performed. Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples. The numbers in Examples and Comparative Examples are parts by weight. Example 1 100 parts of polyester resin (A), the above compound example (a) 5
After mixing and pulverizing in a ball mill, the mixture is melt-kneaded in a roll mill, cooled, coarsely pulverized in a hammer mill, and then pulverized in an air jet type pulverizer. The resulting fine powder is classified to select 1 to 20 microns, and 1% by weight of colloidal silica is added thereto to form a toner. A developer was prepared by mixing 90 parts of carrier (reduced iron powder manufactured by Dowa Iron Powder) with 10 parts of this toner. Using this developer, NP color copying machine (manufactured by Canon Inc.)
When 5,000 copies were made in succession using this method, the copies had no fog, had extremely good spectral reflection characteristics, and had a clear cyan color. Furthermore, when copying a combination of a yellow toner using an azo dye and a magenta toner using a polymethine dye/pigment, a clear color image with extremely good color reproducibility was obtained. Reproduced in black. Example 2 A toner was obtained in the same manner as in Example 1, except that the toner composition was 100 parts of polyester resin (B) and 8 parts of the above-mentioned compound example (b). This toner was used as a developer similar to that in Example 1, and when used in the same manner as in Example 1, the copied images produced by a continuous copying machine of 5000 copies exhibited an extremely clear cyan color with no fog. Furthermore, when copying a combination of a yellow toner using an azo dye and a magenta toner using a polymethine dye/pigment, a clear color image with excellent color reproducibility of the original was obtained. has been reproduced in pure black. Example 3 A toner was obtained in the same manner as in Example 1, except that the toner composition was 100 parts of polyester resin (C) and 2 parts of the aforementioned compound example (a). When a developer was prepared and used from this toner in the same manner as in Example 1, it was continuous.
The copied image after 5000 copies had an extremely clear cyan color with no fog. Furthermore, when copying a combination of yellow toner using azo dyes and pigments and magenta toner using polymethine dyes and pigments, a clear color image with extremely good color reproducibility was obtained. Reproduced in pure black. Example 4 A toner was obtained in the same manner as in Example 1, except that the toner composition was 100 parts of polyester resin (E) and 5 parts of the aforementioned compound example (a). Example 1 with this toner
A similar developer was used, and when 5,000 copies were continuously made using this developer in a low temperature, low humidity environment (15°C, relative humidity 10%), the copies exhibited an extremely clear cyan color with no fog. Example 5 A toner was obtained in the same manner as in Example 1 except that the toner composition was 100 parts of polyester resin (E) and 5 parts of the above compound (c). This toner was used as a developer in the same manner as in Example 1, and 5,000 copies were continuously made using this developer in a high-temperature, high-humidity environment (35°C, relative humidity 80%), and the copies were extremely fog-free. It exhibited a clear cyan color. Example 5 A toner was obtained in the same manner as in Example 1 except that the toner composition was 100 parts of polyester resin (D), 10 parts of the above compound example (d), and 10 parts of a copolymer of dimethylaminoethyl methacrylate and styrene. . This toner was used as a developer in the same manner as in Example 1, and when a negative latent image on zinc oxide photosensitive paper was developed using this developer, an extremely clear cyan positive image was obtained. Comparative Example 1 The same procedure as in Example 1 was carried out except that 0.1 part of the compound (a) was used as the toner. The copied image had a light density as a whole and did not exhibit a clear cyan color. Furthermore, when copies were made using a combination of yellow toner using azo dye and magenta toner using polymethine dyes and pigments, the copied image had an orange color overall, and the portion of the original that corresponded to black was not pure black. Nakatsuta. Comparative Example 2 The same procedure as in Example 1 was carried out except that the toner composition was changed to 15 parts of Compound Example (a). The copied image had a so-called fogging phenomenon with an increased background density, resulting in an unclear image. Moreover, this fogging phenomenon became even more noticeable after 5,000 copies were made continuously. Furthermore, when copying a combination of yellow toner using an azo dye and magenta toner using a polymethine dye/pigment, the copied image turned out to have a significant bluish fog overall, which also corresponded to the black of the original. The part that was painted was not pure black. Comparative Example 3 Copper-phthalocyanine (C.
A cyan toner was prepared in the same manner as in Example 1 except for using 5 parts of I.Pipment blue 15),
A developer was prepared in the same manner as in Example 1, and then
A copying test was conducted in the same manner as in Example 1. Furthermore, in the same manner as in Examples 4 and 5, the test was carried out under a low temperature and low humidity environment (15°C relative humidity 10%) and a high temperature and high humidity environment (35°C relative humidity 10%).
Copying tests were conducted at 80% relative humidity. The test results of the toners of Examples 1, 4, and 5 and the toner of Comparative Example 3 are shown in the table below.

[Table] ○: Good △: Fair ×: Poor The reason why the cyan toner of Comparative Example 3 is inferior in fog and image density compared to the cyan toner of the present invention is that The organic pigment of the general formula [] has a substituent with a polar group and therefore has good affinity with polyester resin, whereas the copper-phthalocyanine pigment (CIPipment blue 15) used in Comparative Example 3
This is thought to be due to the fact that it does not have a substituent having a polar group. That is, the polyester resin used in the present invention has a low viscosity and is not easily subjected to shearing force during melt-kneading, so it is difficult to uniformly disperse the cyan pigment in the kneaded product. This is because the organic pigment of the general formula [] has a substituent having a polar group, so it has a high affinity with the polyester resin, and therefore was well dispersed in the kneaded material. It is thought that the difference in dispersibility in the kneaded material is caused by the difference in development characteristics in the toner. Experimental Example Using the cyan toner of Example 1 and the yellow toner and magenta toner described in Example 1, images of each color were printed using an NP-color copying machine. Similarly, cyan toner was used in Comparative Example 3, and cyan toner was used in Example 1.
Images of each color were produced using the yellow toner and magenta toner described in . When the cyan toner of the present invention was used, the range of color tone reproducibility was wider in the chromaticity diagram compared to the cyan toner of Comparative Example 3. As explained above, the novel combination of colorant and resin according to the present invention has extremely excellent spectral reflection characteristics, and by superimposing the three colors of yellow toner and magenta toner, it exhibits an intense black color. It was possible to obtain a cyan toner for electrophotography that can maintain a high level of image quality despite changes in the environment.

Claims (1)

[Claims] 1. A polyester resin consisting of an aliphatic acid, an aromatic acid, and bisphenol alcohol is used as a binder resin, and the temperature at which the melt viscosity of the polyester resin shows 10 ⁵ cp is T ₁ , and 0.5× 10 The temperature at which ⁵ cp is shown is
When T ₂ , the following conditions T ₁ = 100 to 150℃, ｜△T｜=｜T ₁ −T ₂ ｜=10
~30℃, the polyester resin satisfies
A cyan toner for color electrophotography, characterized in that it contains a blue organic pigment represented by the following general formula [] in an amount of 0.5 to 10% by weight based on a binder resin. General formula [] [X ₁ to ₄ represent [Formula] [Formula] or -H (wherein R and R' represent an alkylene group having 1 to 5 carbon atoms),
However, the number of hydrogen atoms in X ₁ to _{X 4} is 0, 1, 2, or 3. ]