| 摘要 |
1336819 Photo-copying apparatus INTERNATIONAL BUSINESS MACHINES CORP 24 Sept 1971 [6 Nov 1970] 44578/71 Heading G2A A projection optical system in, e.g. an electrophotographic copier, for imaging a document on a first plane 5 on to an image-receiving surface at a second plane 2a, includes a lens 12 and a reflector 11, the lens being mounted to move rectilinearly between two limit positions for selectively varying the magnification ratio of the image, the motion of the lens between the said positions having components along and perpendicular to the lens optical axis; the reflector 11 being mounted to move between two limit positions to vary the length of the optical path between the first and second planes; and means being provided for moving the reflector to a position appropriate to that selected for the lens. The mirror 11 is movable both parallel and perpendicular to itself. A second fixed mirror 10 completes the optical system, and flash lamps 6, 7 are provided for effecting whole frame exposure. The movement of parts 11, 12 is such that a pair of reference lines in the first plane 5 are imaged at a pair of reference lines on the second plane 2a, regardless of the selected magnification ratio. |
