| 摘要 |
PURPOSE: To prevent image deviation from occurring by specifying surface pressure by the pressing force of a transfer roller to a photoreceptor drum. CONSTITUTION: A transfer material is allowed to pass between an image carrier having the superposed toner image of two or more colors and a transfer means, and the toner image is electrostatically transferred on the transfer material altogether while pressing the transfer means so that the surface pressure by the pressing force exerted on the image carrier is <=1000g/cm<2> . In order to form the image at a higher speed, the transfer roller must come into press-contact with and be separated from the photoreceptor drum in the midst of writing at least at the time of consecutive printing, and it must come into press-contact with the photoreceptor drum in the midst of developing even in the case of one print. In such press-contact and separation, when the surface pressure by the pressing force is 800g/cm<2> , for example, the variation of the circumferential speed of the photoreceptor drum to the rotational angle position of the photoreceptor drum is small and does not influence the image. However, when the surface pressure is 1500g/cm<2> , the variation is larger and if the transfer roller comes into press-contact with or is separated from the photoreceptor drum in the midst of writing by an optical system and in the midst of developing, the deviation in the image is generated. |
