1. An image forming apparatus comprising: a movable first image bearing member on which a toner image is formed; and a movable second image bearing member which is brought into contact with said first image bearing member and to which the toner image on said first image bearing member is transferred, wherein a dot-shaped dot image formed of a toner different from the toner image is formable on said first image bearing member, and wherein a distance between dot centers of the dot images is equal to or smaller than a width of a contact part between said first image bearing member and said second image bearing member in a moving direction of said first image bearing member.