PURPOSE: To prevent the position deviation of the image projected on a photosensitive drum by providing a means for detecting the direction of the film image for matching the positions of the film image and a transfer material.

CONSTITUTION: The light from a light source 19 of a detector CL is imaged with a lens 20 on the bottom surface of an original placing plate 17 of an aperture mask 1 supporting a film F, and the reflected light thereof is conducted with a lens 21 to a photodetector 22. The level difference between the photographic film F and the mask 1 is detected and the directions F1, F2 of the film are detected. The timing for paper feeding is controlled according to the detected direction, and the matching of the positions between the film F and transfer paper is accomplished. The deviation of the position of the image projected on the photosensitive drum is thus prevented.