Patent ID: 7215898
Filing Date: 2007-05-08
Classification: G03G

Abstract:
1. An apparatus for forming a multi-color image, comprising: a plurality of developer units that contain a plurality of single-color developer materials, respectively, the plurality of developer materials having respective different single colors; a latent-image forming device that forms each latent image on a photoconductor, using each corresponding one of the plurality of developer materials that has been supplied from each corresponding one of the plurality of developer units; and a developer-image forming device that visualizes the each latent image which has been previously formed, into each corresponding single-color separated-developer-image, and that electrically transfers in sequence the each single-color separated-developer-image which has been previously formed, from the photoconductor onto an image transferred medium onto which the each single-color separated-developer-image is to be sequentially transferred, for a superimposed registration of a plurality of single-color separated-developer-images, to thereby form a multi-color composite-developer-image on the image transferred medium, wherein the each developer unit is configured to collect a residual of the each developer material which remains on the photoconductor after a normal transfer of the each corresponding single-color separated-developer-image from the photoconductor onto the image transferred medium, wherein a surface potential of a previously-formed separated-developer-image subset of a plurality of separated-developer-images which has been previously transferred medium at at least one of selected times prior to and a selected time after a subsequent transfer in which a remainder of the plurality of separated-developer-images is transferred onto the image transferred medium after a previous transfer of the previously-formed separated developer-image subset onto the image transferred medium, falls within a predetermined range for suppressing a reverse transfer of a part of the each developer material on the image transferred medium from the image transferred medium onto the photoconductor at the subsequent transfer, and wherein an amount of the each developer material which is to be affixed to the photoconductor for formation of a reference image is set to a value for allowing the surface potential of the previously-formed separated-developer-image subset which has been transferred onto the image transferred medium, to fall within the range.