Patent ID: 7013102
Filing Date: 2006-03-14
Classification: G03G

Abstract:
1. An image forming apparatus, comprising: at least one first image carrier configured to carry a chromatic color toner image formed thereon; a second image carrier configured to carry a black toner image formed thereon; at least one first gear configured to rotate to drive the at least one first image carrier to rotate; a second gear configured to rotate to drive the second image carrier to rotate; and a control device configured to control respective rotation stop-positions of the at least one first gear and the second gear, wherein a color image is formed in a color mode by transferring the chromatic color toner image formed on the at least one first image carrier onto a transfer material and by transferring the black toner image formed on the second image carrier onto the transfer material while superimposing each other on the transfer material, and a black image is formed in a monochrome mode by halting the at least one first gear and the at least one first image carrier and by transferring the black toner image formed on the second image carrier onto the transfer material, and wherein the control device controls the at least one first gear and the second gear to stop rotating at positions different from rotation start-positions of the at least one first gear and the second gear, respectively, while maintaining a predetermined phase relation between the at least one first gear and the second gear in the color mode, and the control device controls the second gear to stop rotating at a position substantially equal to a rotation start-position of the second gear in the monochrome mode.