Patent ID: 7959151

Claim:
An image forming apparatus configured to convey a recording medium through a sheet conveying path to an image forming position and form an image on the recording medium, the image forming apparatus comprising: an edge position detector to detect a position of a side edge of a recording medium along a width direction perpendicular to a sheet travel direction of the recording medium in the sheet conveying path; and a controller, the controller configured to recognize, based on detection results obtained by the edge position detector, the position of the side edge at multiple detection positions of the recording medium in the sheet travel direction of the recording medium, the multiple detection positions including a detection position located within a dog ear region in the vicinity of either a leading edge or a trailing edge of the recording medium in the sheet travel direction, the multiple detection positions including three or more detection positions, calculate an inclination of either a line connecting two or more points on side edges of the three or more detection positions or an edge-to-edge line obtained by approximating the side edge in the width direction of the two or more points, and determine whether inclinations of two edge-to-edge lines obtained based on the two or more points on the side edges of the recording medium in the width direction, the edge-to-edge lines having different combinations of the two or more points of the side edges in the width direction, are different.