Patent ID: 6952557

Claim:
A method for setting the rotational speed of register rollers in an image forming apparatus for forming an image by driving a recording medium transporting member while feedback control is carried out, the image forming apparatus comprising an image carrier for carrying a toner image, the register rollers for transporting recording media at a predetermined timing by rotationally driving the register rollers, the recording medium transporting member for carrying the recording media transported from the register rollers on its surface to pass the recording media by a transfer area opposing the image carrier, means for driving the recording medium transporting member so that its surface moves, means for detecting the speed of movement of the surface of the recording medium transporting member, and controlling means for feedback controlling the driving means based on the detection by the detecting means so that the speed of movement of the surface of the recording medium transporting member is kept at a target value equal to the speed of movement of the surfaces of the register rollers, the method comprising the steps of: transferring toner marks on the image carrier onto the recording media transported at different rotational speeds by rotationally driving the register rollers at the different rotational speeds while the feedback control is not carried out, detecting displacements of the toner marks transferred on the recording media from ideal transfer positions, and setting the rotational speed of the register rollers for a subsequent image forming operation to the rotational speed of the register rollers when the displacement is smallest.