| 摘要 |
PURPOSE:To move a lens and a mirror in parallel and forming a variable power image by using a variable power optical system as the optical system of a copying machine, and only setting the sum theta of the incidence angle and projection angle of a main light beam to a lens and the angle alpha between the main beam incident to a mirror arranged at the object space side of the lens and the main beam projected from the lens. CONSTITUTION:An original 1 is placed on platen glass 2, which is scanned as shown by an arrow. Illumination light from an exposure lamp 3 is reflected by the original 1 to form an image on a photosensitive drum 5 through the 1st mirror M1, the 2nd mirror M2, an in-mirror lens 4, and the 3rd mirror M3. The lens and reflecting mirror are so arranged that m(sintheta+sinalpha)-sin(theta+alpha)=0, where theta is the sum of the incidence angle and projection angle of the main light beam of the in-mirror lens 4 and alpha is the angle between the main light beam incident to the 2nd mirror M2 and the main light beam projected from the in-mirror lens 4. The theta and angle alpha are determined to form a variable power image only by moving the lens and mirror in parallel. |
