An image forming apparatus, performing a corresponding method of image forming, includes an image carrier, a writing unit, a developing unit, a charging member configured to rotate continuously with the image carrier at a portion contacting the image carrier and uniformly charge a surface of the image carrier while contacting a surface thereof with the surface of the image carrier, a charge bias applying unit configured to apply a charge bias to the charging member, and a controller configured to control of driving of the image carrier and the charging member and reduce at a charge nip at a given timing a linear velocity ratio of a travel speed of the surface of the charging member to a travel speed of the surface of the image carrier.