Image forming apparatus 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;
• a current supply member configured to come into contact with the intermediate transfer belt;
• and
• a power source configured to apply voltage to the current supply member,
• 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 a toner image is transferred by primary transfer from the image bearing member to the intermediate transfer belt, by applying voltage from the power source to the current supply member,
• and wherein 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, is an innermost layer among the plurality of layers, has a lower electrical resistance than the first layer, and has surface resistivity in a range of 4.0×106 Ω/□ or less.