Patent US 8,908,193

An image forming apparatus for detecting surface conditions of a recording sheet on which an image is formed, includes a light source configured to emit a first light beam and a second light beam, an image capture device configured to capture a first image of a surface of the recording sheet illuminated with the first light beam and a second image of the surface of the recording sheet illuminated with the second light beam. A first straight line including a ray in a center of the first light beam and a second straight line including a ray in a center of the second light beam intersect with each other, when each straight line is projected onto the surface of the recording sheet, and a detection device configured to detect information about the unevenness on the surface of the recording sheet based on the first image and the second image.