Patent ID: 8099022

Claim:
A color image forming apparatus comprising: a first endless photoconductive member that holds a monochrome image; a second endless photoconductive member that holds an image of a first color for obtaining a color image according to a subtractive process; a third endless photoconductive member that holds an image of a second color for obtaining a color image according to the subtractive process; a fourth endless photoconductive member that holds an image of a third color for obtaining a color image according to the subtractive process; a first driving mechanism that imparts rotation for moving an image holding surface of the first endless photoconductive member in a predetermined direction; a second driving mechanism that imparts rotation for moving image holding surfaces of the second, third, and fourth endless photoconductive members in a predetermined direction; a first rotation detecting mechanism that detects a first rotation phase of the first driving mechanism; a second rotation detecting mechanism that detects a second rotation phase of the second driving mechanism; and a rotation control mechanism that controls the rotation of the first driving mechanism and the second driving mechanism on the basis of detection results of the first rotation detecting mechanism and the second rotation detecting mechanism, after each of the first, second, third, and fourth endless photoconductive members has reached a uniform rotating speed after power is supplied.