Abstract: An image forming apparatus includes a photoconductor, a transfer roller, and a power supply for providing a voltage signal for the transfer roller to transfer surface attachments on the transfer roller to the photoconductor. Moreover, before providing the voltage signal for the transfer roller, a surface voltage level of the photoconductor can be adjusted according to the voltage signal in order to ensure that the surface voltage level of the photo conductor can be kept in a safe charging range. Therefore, the transferring efficiency of the transfer roller is ensured and damage to the photo conductor is prevented.

Abstract: A developing method improves the printed image quality of an image-forming device by removing surplus charge potential to make the surface potential of a photoreceptor charged during first and second charging steps be the same for next developing, or by inputting different voltages to the developing units. An image-forming device is also disclosed.

Abstract: An apparatus and method for shifting the image-forming region of a printing device is disclosed. The apparatus includes a photoconductor, an encoder, several rollers, and a controlled device. The present invention is used to shift the image-forming region in the photoconductor by the controlled device. The damage of the image-forming region in the photoconductor can be reduced. The lifetime of the photoconductor can be extended. In addition, the controlled device uses firmware to shift the image-forming region. The shifting method can be a sequential mode or random mode.