METHOD FOR MEASURING QUANTITY OF FACE INCLINATION OF SCANNING OPTICAL SYSTEM

摘要

PURPOSE:To provide a method for measuring the quantity of face inclination of a scanning optical system in which the position of the spot of a laser beam in the sub-scanning direction at the time of optically scanning a face to be scanned is detected in only one scanning for one reflection face and rotation fluctuation of a rotating polygon mirror does not influence thereon. CONSTITUTION:A beam which is reflected from a rotating polygon mirror and made to scan the surface to be scanned is received by a photodetector means 2 for every scanning. A plurality of pieces of data taken by the photodetector means at every scanning is stored in real time in a memory 7. The position of the spot of the beam in the sub-scanning direction perpendicular to the main scanning direction is detected by each scanning by utilizing the data stored in the memory to measure the quantity of the face inclination of the rotating polygon mirror.