PURPOSE: To detect the position of an original and density of an original background by detecting reflectance of the inside face of an original pressing plate, the original background, and an original character information part and comparing one with another.

CONSTITUTION: A photodetector 9 receives light reflected from an original 0 placed on a moving platen 1 and illuminated with a lamp 10 to detect reflectance. This lamp for measuring the reflectance may be installed separately from an illumination lamp 10 for projecting the original image on a drum 11. An inside face of an original pressing plate 2 has been formed of a material as high in quality as Kent paper, so its reflectance is higher than that of the background of the original 0. The position of the original 0 is detected from their differences. The original density is also detected from the reflectances of an original character information part or the original background part, and the inside face of the plate 2, and copying conditions are adjusted so as to form the optimum density.