| 摘要 |
PURPOSE:To perform plural times of scanning with one turning movement of a specular surface by making the light beam entering a rotary polyhedral mirror incident time dividedly to different beam paths. CONSTITUTION:When laser light is reflected by a beam splitter 4 and advances in a direction 2a, and if the angle between the luminous flux 2a thereof and the face 8 of a rotary polyhedral mirror 6 is 45 deg., the light is reflected by the face 8, advances in a direction 3b and forms its image on an imaging plane O. If the face 8 of the mirror 6 is located at 11 deg. before the same, the image is formed on an imaging plane 12. When the angle between the light 2a and the face 8 advances further from 45 deg. to 56 deg., the image is formed on an imaging plane 13. When the mirror 6 is rotated non-effectively by 8 deg. rotating angle, the light 2b heading through the mirror 7 toward the mirror 6 falls onto the face 8 of the rotary mirror and is reflected in the direction of light 3a, drawing the same main scanning line as the light 2a. The efficiency is higher than in the case in which the light is made incident to the polyhedral mirror from one direction only. |
