JPS6355699B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a developer containing a mixture of toner and carrier, and particularly to a black toner suitable for a method of detecting developer concentration by measuring infrared reflection or transmission density of the developer. Generally, a developer consisting of a mixture of carrier and toner is used as a developer for electrophotography or electrostatic recording. For this reason, when applying the magnetic brush development method, for example, the mixing ratio of the magnetic carrier of the developer and the toner (eg, colored resin fine powder) is an extremely important factor in terms of the development effect. That is, the developer attached to the magnet slides over the electrostatic latent image and visualizes the latent image with toner. As a result, toner is gradually consumed from the developer, and the ratio of toner to carrier decreases, that is, the concentration of the developer decreases, and the density of the developed image gradually becomes thinner. Therefore, toner is appropriately replenished, but in this case, if more toner is replenished than appropriate, the image density becomes too high and fogging increases. Therefore, in order to continuously obtain images with desirable tones, it is necessary to accurately detect the concentration of the developer. Conventionally, several methods are known for automatically controlling the concentration of developer. For example, Tokuko Sho 38-17245
The method proposed in et al. uses the fact that the carrier and toner are of different colors and the mixed color density of the developer, which is a mixture of the carrier and toner, changes as the toner is consumed. The change is optically detected and the supply of toner to the developer is controlled according to the change to keep the developer concentration constant. However, this method cannot be used if the carrier and toner are similar in tone. In the generally widely used magnetic brush method, a black toner made by mixing resin, carbon, and a control agent is used as the toner, and various iron powders such as electrolytic iron powder, reduced iron powder, and atomized iron powder are used as the carrier. Alternatively, those iron powders whose surfaces are oxidized are used. In this case, the diffuse reflectance of both the carrier and the toner is small, and not only is the difference between them small, but the amount of light reflected from the developer is small, making it difficult to use it for detecting the developer concentration. The present applicant previously provided a method for detecting the reflection or transmission density of the developer in the infrared region as a method for accurately detecting the developer concentration (Japanese Patent Application Laid-Open No. 1983-1973-1).
No. 107853). According to this method, the change in reflectance due to the developer concentration, that is, the change in the amount of reflected light, can be greatly reduced, which not only improves detection accuracy, but also has the advantage that it can be used for color copies as well as black and white copies. I have it too. The present invention has been made in view of the above-mentioned current situation. That is, an object of the present invention is to provide a black toner containing a colorant that has sufficient reflection or transmission in the infrared region. Further, the purpose of the present invention is to produce black and white copies, two-color copies,
The object of the present invention is to provide a density detection method using black toner that can accurately detect developer density in color copying such as full-color copying. This purpose can be achieved by using a toner that reflects or transmits infrared light and uses a black mixture of two or more colorants such as dyes and pigments that are not black in color. achieved. Examples of black colorants include carbon black, acetylene black, lamp black, bone black, graphite, black iron ferrite, mineral black, and aniline black, but none of these have sufficient reflection in the infrared region. It is not preferred as a coloring agent for the toner of the present invention. However, in the case of an apparently black mixture made by blending two or more dyes and pigments selected from yellow, orange, brown, red, purple, green, blue, etc. in an appropriate ratio, each of these components is sufficient in the infrared region. While it functions as a black coloring agent due to its high reflection, unlike the above-mentioned single black coloring agent, it exhibits sufficient reflection in the infrared region, making it possible to accurately detect developer concentration. . Specifically, the present invention provides azo yellow dyes and pigments, quinoline yellow dyes and pigments, azo red dyes and pigments, anthraquinone red dyes and pigments, which are coloring materials that reflect or transmit infrared light and are not black. Two or more dyes and pigments selected from xanthene red dyes and pigments, anthraquinone blue dyes and pigments, phthalocyanine blue dyes and pigments, azo brown dyes and pigments, azo orange pigments, phthalocyanine green dyes and pigments, and azo purple dyes and pigments. The present invention relates to a black toner characterized in that it contains a mixture that has been blended to produce a black color. Furthermore, the present invention provides azo yellow dyes and pigments, quinoline yellow dyes and pigments, azo red dyes and pigments, which are coloring materials that reflect or transmit infrared light and are not black.
Selected from anthraquinone red dyes and pigments, xanthene red dyes and pigments, anthraquinone blue dyes and pigments, phthalocyanine blue dyes and pigments, azo brown dyes and pigments, azo orange dyes and pigments, phthalocyanine green dyes and pigments, and azo purple dyes and pigments. A method for detecting the concentration of a developer, the method comprising detecting reflected light or transmitted light in the infrared region of a developer prepared by mixing a carrier with a black toner containing a blackened mixture of two or more types of dye pigments. Regarding. Any combination of non-black dyes and pigments can be preferably used in these black mixtures, and the blending ratio can be determined depending on the coloring power of each dye and pigment. These black mixtures have a ratio of 0.1 to the binder resin.
Weight% ~ 50% by weight (more preferably 0.2% by weight ~
20% by weight), and if necessary, a small amount of carbon black or the like may also be used as an auxiliary coloring agent in case of insufficient blackness. Of course, in this case, the amount of carbon black added must be limited to a range that ensures sufficient reflection in the infrared region. A wide variety of binder resins can be used for toners, including known ones, such as polystyrene, chloropolystyrene, poly-α-methylstyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, and 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-ethyl methacrylate copolymer (styrene-methacrylate copolymer, etc.) methyl acid copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-phenyl methacrylate copolymer, etc.), styrene-α-methyl chloroacrylate copolymer,
Styrenic resins such as styrene-acrylonitrile-acrylic acid ester copolymers (unipolymers or copolymers containing styrene or styrene substitutes), vinyl chloride resins, styrene-vinyl acetate copolymers,
Rosin-modified maleic acid resin, phenyl resin, epoxy resin, polyester resin, low molecular weight polyethylene, low molecular weight polypropylene, ionomer resin, polyurethane resin, silicone resin, ketone resin, ethylene-ethyl acrylate copolymer, xylene resin, polyvinyl butyral resin, etc. However, particularly preferred resins for carrying out the present invention include styrene resins, polyester resins, silicone resins, and epoxy resins.
Moreover, the above resins are not limited to being used alone, but can also be used in combination of two or more. In the developer according to the present invention, a fluidity modifier such as colloidal silica is added to the toner particles.
It may be added in an amount of about 0.01% to 5% by weight (more preferably 0.1% to 2% by weight). The present invention will be explained in more detail with reference to Examples below. Comparative examples are also shown in order to more clearly understand the effects of the present invention. Example 1 1.0 parts by weight of azo yellow dye, azo red dye
1.5 parts by weight and 1.8 parts by weight of anthraquinone blue dye were thoroughly mixed to obtain 4.3 parts by weight of a black mixture. 100 parts by weight of polystyrene resin was added to this mixture, and after thorough premixing, the mixture was melt-kneaded in a roll mill, cooled, and then coarsely ground using a hammer mill, and then finely ground using an air jet type pulverizer. Furthermore, the obtained finely pulverized material is classified to
20μ was selected as the toner. 100 parts by weight of this toner and 900 parts by weight of reduced iron powder were mixed to prepare a developer. The spectral diffuse reflectance of this developer in the visible and infrared regions and the spectral diffuse reflectance of the reduced iron powder used are shown in FIG. It can be seen that the difference in reflectance increases in the infrared region. Comparative Example 1 A toner was prepared and a developer was obtained in substantially the same manner as in Example 1 except that 5 parts by weight of carbon black was used instead of the black mixture of Example 1. The spectral diffuse reflectance of this developer is shown in FIG. It can be seen that the reflectance is low even in the visible and infrared regions, making it unsuitable for developer concentration detection based on reflection density. Example 2 A toner was prepared and a developer was obtained in substantially the same manner as in Example 1 except that a styrene-acrylic copolymer resin was used in place of the styrene resin in Example 1. The spectral reflectance of this developer showed a curve almost similar to that of Example 1, and showed sufficient reflection in the infrared region, making it possible to accurately detect the developer concentration. Examples 3 to 6 Developers were obtained in the same manner as in Example 1, except that the black mixtures in Example 1 were replaced with those shown in the table below. All of these developers showed sufficient reflection in the infrared region.

[Table] Examples 7 to 9 Developers were obtained in the same manner as in Experimental Example 1, except that the black mixture of Example 4 was used and the toner binder resin was replaced with those shown in the table below. All of these developers showed sufficient reflection in the infrared region.

【table】 [Brief explanation of the drawing]

FIG. 1 is a characteristic diagram showing the spectral diffuse reflectance in the visible and infrared regions of the developer of the example of the present invention, the developer of the comparative example, and the iron powder used alone.

Claims (1)

[Scope of Claims] 1. Azo yellow dyes and pigments, quinoline yellow dyes and pigments, azo red dyes and pigments, anthraquinone red dyes and pigments, and xanthene dyes and pigments that reflect or transmit infrared light and are not black. A combination of two or more dyes and pigments selected from red dyes and pigments, anthraquinone blue dyes and pigments, phthalocyanine blue dyes and pigments, azo brown dyes and pigments, azo orange pigments, phthalocyanine green dyes and pigments, and azo purple dyes and pigments. A black toner characterized in that it contains a mixture that has been blackened. 2. Azo yellow dyes and pigments, quinoline yellow dyes and pigments, azo red dyes and pigments, anthraquinone red dyes and pigments, xanthene red dyes and pigments, and anthraquinone dyes that reflect or transmit infrared light and are not black. A black mixture obtained by blending two or more dyes and pigments selected from blue dyes and pigments, phthalocyanine blue dyes and pigments, azo brown dyes and pigments, azo orange dyes and pigments, phthalocyanine green dyes and pigments, and azo purple dyes and pigments. A method for detecting the concentration of a developer, the method comprising detecting infrared reflected light or transmitted light of a developer that is a mixture of a carrier and a black toner containing a carrier.