Patent ID: 8804180

Claim:
An image forming apparatus for forming an image on a sheet of paper, the apparatus comprising: a first deviation detection portion that detects a first amount of deviation of the sheet of paper in relation to a reference position of an edge of the sheet of paper; a pair of registration rollers that transport the sheet of paper, the pair of registration rollers being positioned at a downstream side of the first deviation detection portion; a second deviation detection portion that detects a second amount of deviation of the sheet of paper in relation to the references position of the edge of the sheet of paper, the second deviation detection portion being positioned at free downstream side of the pair of registration rollers; an image forming portion that receives the sheet of paper transported by the pair of registration rollers to form the image, and includes an exposing portion for writing the image, the image forming portion being positioned at the downstream side of the second deviation detection portion; and a control portion that is configured to perform a first control to correct an image writing position in the exposing portion based on the first amount of deviation of the sheet of paper along a direction that is perpendicular to a transporting direction of the sheet of paper and is configured to perform a second control to move the pair of the registration rollers with them nipping the sheet of paper based on the second amount of deviation of the sheet of paper along the direction that is perpendicular to the transporting direction of the sheet of paper, wherein the control portion determines whether or not the first amount of deviation of the sheet of paper exists within the moving adjustment range of the pair of registration rollers in the second control, the control portion performs the first control to correct the reference position of the edge of the sheet of paper to be detected by the second deviation detection portion when the first amount of deviation of the sheet of paper exceeds the moving adjustment range of the pair of registration rollers, the control portion controls the second deviation detection portion to detect the second amount of deviation of the sheet of paper in relation to the reference position corrected by the first control, and the control portion performs the second control to move the pair of registration rollers based on the detected second amount of deviation of the sheet of paper.