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AssigneeRicoh Company, Ltd.
InventorsShinichi Kuramoto, Kanjirou Kawasaki, Shohichi Sugimoto
Estimating the term…
A color toner selected from the group consisting of a yellow toner, a magenta toner, and a cyan toner, and mixtures thereof, which includes a binder resin and a color pigment, wherein a C* value of a fixed red image formed by a combination of a layer of the yellow toner having a weight of 8 g/m2 and a layer of the magenta toner having a weight of 8 g/m2 is not less than 80, and wherein a hexagon formed by six points in a *-b* chromaticity coordinates of a fixed yellow image formed by a layer of the yellow toner having a weight of 8 g/m2, the fixed red image, a fixed magenta image formed by a layer of the magenta toner having a weight of 8 g/m2, a fixed blue image formed by a combination of a layer of the magenta toner having a weight of 8 g/m2 and a layer of the cyan toner having a weight of 8 g/m2, a fixed cyan image formed by a layer of the cyan toner having a weight of 8 g/m2, and a fixed green image formed by a combination of a layer of the cyan toner of 8 g/m2 and a layer of the yellow toner having a weight of 8 g/m2, has an area of not less than 13600. Preferably, the yellow toner includes a benzimidazolone pigment, the cyan toner includes β copper phthalocyanine, and the magenta toner includes at least one of either Naphthol Carmine F6B or a mixture of Naphthol Carmine F6B with Naphthol Carmine FBB.
A color toner selected from the group consisting of a yellow toner, a magenta toner, and a cyan toner, and mixture thereof, comprising a binder resin and a color pigment;
A method for forming a color image, comprising:
A color toner selected from the group consisting of a yellow toner, a magenta toner, and a cyan toner, and mixtures thereof, each toner comprising a binder resin;
A method for forming a color image, comprising:
Dependencies are inferred from the claim text.
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Plasticisers; Charge controlling agents: organo-metallic compounds
With toner particles: colouring agents for toner particles
Characterised by the developing step, e.g. the properties of the colour developers: developing using a step for deposition of subtractive colorant…
Electrography
Term end not estimated
1. Field of the Invention
The present invention relates to color toners and an image forming method using the color toners, and more particularly to a yellow, magenta, and cyan toner which are used for forming color images using electrophotography and image forming methods using the color toners.
2. Discussion of the Background
Various other objects, features and attendant advantages of the present invention will be more fully appreciated as the same becomes better understood from the detailed description when considered in connection with the accompanying drawing in which like reference characters designate like corresponding parts throughout and wherein:
FIG. 1 is a graph of a*-b* chromaticity coordinates in which hexagons are formed by the respective six points of the color images prepared in Examples 1 to 4 and Comparative Examples 1 and 2.
In color toner images, it is very important to prepare a red toner image having good brightness. The present inventors discovers that such a bright red image can be prepared by using a yellow and magenta toner such that when a combination of the yellow toner image of 8 g/m2 and the magenta toner image having a weight of 8 g/m2 is formed and then the formed image is fixed, the C* value of the resultant red image is not less than 80.
It is also important to prepare color images having good a color tone. The present inventors also discovers that such color images having good color tone can be prepared by using a yellow, magenta and cyan toner such that a hexagon formed by six points in a*-b* chromaticity coordinates of a fixed yellow image which is formed by a layer of the yellow toner having a weight of 8 g/m2, a fixed red image which is formed by a combination of a layer of the yellow toner having a weight of 8 g/m2 and a layer of the magenta toner having a weight of 8 g/m2, a fixed magenta image which is formed by a layer of the magenta toner having a weight of 8 g/m2, a fixed blue image which is formed by a combination of a layer of the magenta toner having a weight of 8 g/m2 and a layer of the cyan toner having a weight of 8 g/m2, a fixed cyan image which is formed by a layer of the cyan toner having a weight of 8 g/m2, and a fixed green image which is formed by a combination of a layer of the cyan toner having a weight of 8 g/m2 and a layer of the yellow toner having a weight of 8 g/m2, has an area of not less than 13600.
In order to prepare such color toners, it is preferable that the toners include at least a binder resin and a pigment, and the yellow toner includes a benzimidazolone type pigment, the cyan toner includes β copper phthalocyanine, and the magenta toner includes Naphthol Carmine F6B or a combination of Naphthol Carmine F6B with Naphthol Carmine FBB. By using such toners, the resultant color images have good color reproducibility, particularly good color reproducibility of red and blue images, and good image stability, particularly good light resistance.