| 摘要 |
PROBLEM TO BE SOLVED: To provide an efficient and compact scanning optical system which does not take time in reading and writing an image and does not specially need the fθlens of a wide angle so as to avoid the increase in the size of a device in a laser scanning optical system requiring a long scanning width exceeding 300 mm. SOLUTION: In a scanning optical system using a rotary polygon mirror, a deflection scanning angle is made small by setting the number of the surfaces of a polygon mirror as seven, and the waste of scanning at the outside of an image area is reduced by enhancing an effective scanning ratio to be 75% to 95%, and the occurrence of interference between an incident laser beam and the fθlens is avoided and also the increase in the size of the device is avoided by setting the incident angle of a laser beam to the rotary polygon mirror to be 55°to 70°. COPYRIGHT: (C)2004,JPO |
