DEVICE AND METHOD FOR IMAGE FORMATION

PROBLEM TO BE SOLVED: To surely prevent dust of toner from being generated when a toner image is transferred from an image carrier to a transfer material and to keep an image formation state always satisfactory by surely preventing picture quality from becoming worse. SOLUTION: For an image of >=1,200 dpi in resolution on which dust of toner exhibits great adverse effects on the image quality, a transfer voltage E which does not cause a discharge dc between a non-image part on the surface of a photoreceptor drum 1 and a form P is applied in an area before transfer from a power unit 7 to a transfer roller 4. The discharge start voltage between the non-image part and the form P is lower than the discharge start voltage between an image part on the surface of the photoreceptor drum 1 and the form P. The transfer voltage E is set to a value which does not cause the discharge dc between the non-image part on the drum 1 and the form P so that toner T forming an image part G near the border of the non-image part never moves to the non-image part, thereby preventing the dust of the toner from being produced.