Image forming apparatus and image forming method

An image forming apparatus, including: an image carrier for carrying an image; a transfer roller including a holder member that holds a transfer material, a groove portion in which the holder member is disposed, and an elastic member disposed over the transfer roller except a portion where the groove portion is disposed, the elastic member of the transfer roller is pressed onto the image carrier to transfer an image from the image carrier onto the transfer material; and a gate roller for transporting the transfer material to the holder member, wherein a circumferential velocity v1 (mm/sec) of the elastic member of the transfer roller is lower than a moving speed v2 (mm/sec) of the transfer material transported by the gate roller.