Image forming apparatus

An image forming apparatus, comprising:

• a photosensitive member to bear an electrostatic latent image on a surface thereof;
• a developing device to develop the electrostatic latent image formed on the photosensitive member using toner to form a toner image;
• an intermediate transfer member to bear the toner image on the surface thereof, the intermediate transfer member disposed opposite the photosensitive member and formed into a loop;
• a primary transfer device to transfer the toner image from the photosensitive member onto the intermediate transfer member;
• a secondary transfer device to transfer the toner image from the intermediate transfer member onto a recording medium, the secondary transfer device disposed outside the loop formed by the intermediate transfer member to contact the intermediate transfer member and form a secondary transfer nip therebetween;
• a first power supply to apply a constant-current controlled direct current bias to an inner circumferential side of the intermediate transfer member, the direct current bias having the same polarity as that of the toner image;
• and
• a second power supply to form an alternating electric field between the intermediate transfer member and the recording medium, the first power supply and the second power supply applying predetermined biases simultaneously when the recording medium is in the secondary transfer nip to transfer the toner image thereon,
• wherein the first power supply is disposed inside the loop formed by the intermediate transfer member and the second power supply is disposed outside the loop formed by the intermediate transfer member.