The utility model provides an even when reversing the developer roll, also can suppress the light -emitting -diode array heads positioning method and image forming apparatus that the tinting color disperses to the outside from the developer roll. Embodiment's light -emitting -diode array heads positioning method and image forming apparatus has: photoreceptor, developer roll, restricting board, and thin slice part. After the photoreceptor is expose, form the electrostatic latent image on its surface. The developer roll can just set up with reversing, and during corotation, the developer that will contain the tinting color in the development position is supplied with to the surface of photoreceptor, with static image development. Restricting board limits the bed thickness of the developer attached to on the developer roll in the restriction position. The thin slice parts limit the surface configuration of the developer roll between position and the development position relatively. In addition, the thin slice part have with the butt portion of developer butt. In addition, the thin slice part has the flexion, and this flexion, separates from the developer towards the development position along with following butt portion gradually.