Patent ID: 6608985
Filing Date: 2003-08-19
Classification: G03G

Abstract:
An image forming apparatus, comprising:a first image bearing member; a second image bearing member; an exposure device configured to form a latent image of an image; a developing device configured to visualize a latent image into a visual image; and a first transfer device configured to transfer visual images from the first image bearing member onto the second image bearing member and onto a second side of a recording medium; wherein a latent image of a positioning mark is formed by the exposure device and visualized to a visual positioning mark image by the developing device, and the visual positioning mark image is transferred from the first image bearing member by the first transfer device to form a positioning mark on the second image bearing member at a position outside an image forming area having a size corresponding to that of a maximum size recording medium useable with the image forming apparatus, said image forming area containing a first side visual image transferred by the first transfer device from the first image bearing member, wherein a second side visual image formed by the exposure device and the developing device is transferred from the first image bearing member onto the second side of the recording medium by the first transfer device and the first side visual image is transferred from the image forming area onto a first side of the recording medium by a second transfer device, so that the first and second side visual images are obtained on the first and second sides of the recording medium, respectively, and wherein when forming the first side and second side visual images on the first and second sides of the recording medium, an image forming operation is controlled according to detection of the positioning mark with a positioning mark detecting device such that positions of the first and second side visual images on the first and second sides of the recording medium coincide with each other.