Photoprinting apparatus employing base line control imaging font

摘要

A photoprinting apparatus in which images of symbols on a flat transparency font are projected upon photosensitive material covered by a thin layer of photographic developer. Each symbol on the font is provided with a baseline control indicia and a selected symbol may be projected and viewed prior to exposure employing a light source which will not expose the photosensitive material. Baseline uniformity of the exposed symbols is maintained by sensors which receive an image of the control indicia and regulate the operation of font position adjusting devices prior to each exposure. Novel optical systems, image magnification and minification structures, exposure controls, rapid symbol selection devices, imaging fonts and a cassette for the photosensitive material are also disclosed.