Patent ID: 7970308

Claim:
An image forming apparatus, comprising: an image bearing member for carrying a toner image; a rotatable endless belt; a drive roller which supports said endless belt and rotates said endless belt; a transfer member for transferring a toner image from said image bearing member onto said endless belt or a sheet conveyed by said endless belt electrostatically; a power supply circuit for applying a voltage to said transfer member; a transfer voltage control device for controlling the voltage which said power supply circuit applies to said transfer member; a detecting device which is opposed to said endless belt so as to detect a distance from said endless belt; and a loop correcting device for controlling a loop generated in the endless belt to a predetermined loop amount, wherein said loop correcting device controls the loop of said endless belt to the predetermined loop amount based on the distance detected by said detecting device, by controlling the transfer voltage control device so as to control an electrostatic attraction force of said transfer member to said endless belt.