An image forming apparatus includes a latent image bearer, an electric charging member to electrically charge the latent image bearer uniformly while forming an electric charging nip therebetween by contacting the latent image bearer. A value obtained by dividing a moment of inertia of area of the latent image bearer by the cube of length thereof ranges from about 0.000058 [mm] or more to about 0.000145 [mm] or less. A width of the electric charging nip in a direction of rotation at longitudinal ends of the latent image bearer is larger than that at a longitudinal center thereof. A difference between the width of the electric charging nip in the direction of rotation at the longitudinal ends of the latent image bearer and that at the longitudinal center thereof is larger than an amount of deformation of the latent image bearer generated during rotation at the longitudinal center thereof.