Patent ID: 6141515
Filing Date: 2000-10-31
Classification: G03G

Abstract:
An image forming apparatus for forming multiple images onto a transfer material by transferring color toner images sequentially, comprising:a plurality of image bearing members arranged side by side;image formation means having a digital exposing means for forming a toner image on each of said image bearing members;convey means for conveying a transfer material to toner image transfer positions sequentially;transfer means for transferring the toner image formed on each of said image bearing members to the transfer material at the transfer positions; anda plurality of ultrasonic motors provided corresponding to each of said image bearing members for rotating them, each of said ultrasonic motors being provided coaxial with each of said image bearing members and coupled therewith by a coupling member, each of said ultrasonic motors having rotation detection means on a rotation shaft thereof for detecting rotation speed of the ultrasonic motor,wherein the rotation speed of each ultrasonic motor is controlled independently based on a detected result by said rotation detection means to make the rotation speed of each ultrasonic motor uniform.