| 摘要 |
PURPOSE:To realize a small-sized of structure and to lower the price for the titled scanner, by converting the scan beam obtained by a rotary mirror into parallel beams by using a focusing optical transmitter having at its inside a curved surface of a curvature radius to be converted into a focal distance. CONSTITUTION:The beam scanned by a polyhedral rotary mirror 10 is converted into parallel beams through a focusing optical transmitter 11 and projected onto a photoreceptor drum 13 through a reflector 12 to give the linear scan to a picture onto the drum 13. The transmitter 11 comprises an array of optical fibers 11A having the refractive index decreasing gradually toward the circumference area from the center, and the inner surface 14 of the transmitter 11 is formed into a curved surface in accordance with the curvature radius to be converted into the back focal distance of the beam scan by the mirror 10. Such transmitter 11 is inexpensive compared with an f-theta lens and can be directly replaced with the f-theta lens. Thus a small sized structure and low price are realized for the light beam scanner. |
