A carrier contained in a two component developer used for an image formation method of forming a color image by sequentially transferring multiple color toner images, wherein the carrier resistance R1 of a carrier in a developer, with which a toner image is transferred first, is adjusted to be less than the carrier resistances R2 to Rn (“n” represents a total color number of toners which form images, n≧2) of the carrier in two component developers for each color, which are transferred thereafter. The carrier resistances R1 to Rn of each carrier are adjusted as follows: R1
Description
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view showing an image forming apparatus according to an embodiment of the present invention.
Claims
1. A carrier contained in a two component developer used for an image formation method of forming a color image by sequentially transferring multiple color toner images, wherein the carrier resistance R1 of a carrier in a developer, with which a toner image is transferred first, is adjusted to be less than the carrier resistances R2 to Rn (“n” represents a total color number of toners which form images, n>2) of the carrier in two component developers for each color, which are transferred thereafter.
2. The carrier according to claim 1, wherein the carrier resistances R2 to Rn of the carrier may be the same or different from each another.
3. The carrier according to claim 1, wherein the carrier resistances R1 to Rn of each carrier are adjusted as follows: R1<R2< . . . <Rn according to the order of toner images to be transferred.
4. The carrier according to claim 1, wherein the carrier resistance R1 to Rn of each carrier has a volume resistivity value selected from a range of 1.0×1010 to 1.0×1016 Ω·cm.
5. The carrier according to claim 1, wherein each carrier having the carrier resistance of R1 to Rn contains the same or different conductant agent in a surface coating layer thereof.
6. The carrier according to claim 5, wherein the carrier resistances of R1 to Rn in each carrier is adjusted by the amount of the conductant agent contained in the surface coating layer of each carrier.
7. A two component developer used for an image formation method of forming a color image by sequentially transferring multiple color toner images, and comprising a carrier and a toner, wherein the carrier resistance R1 of a carrier in a developer, with which a toner image is transferred first, is adjusted to be less than the carrier resistances R2 to Rn (“n” represents a total color number of toners which form images, n>2) of the carrier in two component developers for each color, which are transferred thereafter.
8. The developer according to claim 7, wherein the toner concentration is 1 to 20% by weight in the developer.
9. An image formation method for forming a color image by sequentially transferring multiple toner images, wherein the carrier resistance R1 of a carrier in a developer, with which a toner image is transferred first, is adjusted to be less than the carrier resistances R2 to Rn (“n” represents a total color number of toners which form images, n>2) of the carrier in two component developers for each color, which are transferred thereafter.
10. The image formation method according to claim 9, wherein the carrier resistance of the carriers, R2 to Rn, could be the same or different.
11. The image formation method according to claim 9, wherein the carrier resistances R1 to Rn of each carrier are adjusted as follows: R1<R2< . . . <Rn according to the order of toner images to be transferred.
12. The image formation method according to claim 9, wherein the carrier resistance R1 to Rn of each carrier has a volume resistivity value selected from a range of 1.0×1010 to 1.0 ×1016 Ω·cm.
13. The image formation method according to claim 9, wherein the two component developer comprises a toner and a carrier, and the toner concentration in the two component developer is from 1 to 20% by weight.
14. An image forming apparatus comprising a plurality of image supporting materials that are arranged along the moving direction of a transfer medium and sequentially transfer toner images on the transfer medium, and a plurality of developer supporting materials which supply a toner on these respective image supporting materials from two component developers to form toner images, wherein the carrier resistance of the carrier in a developer to be transferred first is less than that of carriers in developers for each color to be transferred thereafter.
Patent Application
20070218394
