Imaging forming apparatus with enhanced primary transferability where primary transfer is performed with electric current flowing in circumferential direction of intermediate transfer belt

An image forming apparatus, comprising:

• an image bearing member configured to bear a toner image;
• a movable endless intermediate transfer belt that has electrical conductivity and is configured of a plurality of layers;
• first, second, and third rollers around which the intermediate transfer belt is stretched, wherein the image bearing member is in contact with a stretch surface of the intermediate transfer belt stretched between the first roller and the second roller, and the third roller stretches the intermediate transfer belt at a position of not being in contact with the stretch surface;
• a secondary transfer member configured to be in contact with an outer peripheral surface of the intermediate transfer belt at a position facing the first roller, and configured to transfer a toner image from the intermediate transfer belt onto a transfer medium after the toner image is transferred from the image bearing member to the intermediate transfer belt;
• and
• a power source configured to apply voltage to the secondary transfer member for transferring the toner image,
• wherein an electric current is made to flow in a circumferential direction of the intermediate transfer belt, the circumferential direction being a direction along a moving direction of the intermediate transfer belt,
• and
• wherein the plurality of layers of the intermediate transfer belt includes
• a first layer that has ionic conductivity and is a thickest layer out of the plurality of layers making up the intermediate transfer belt with respect to the thickness direction of the intermediate transfer belt, and
• a second layer that has electronic conductivity and lower electrical resistance than the first layer, the second layer being an innermost layer among the plurality of layers and having a surface resistivity in a range of 4.0×106 Ω/□ or less.