Patent ID: 6862108

Claim:
An optical printer comprising: a spatial light modulator having an array of micromirrors arranged in a row or in a matrix, said micromirrors being able to tilt each individually between an effective reflecting position and an ineffective reflecting position; a light source section illuminating said micromirror array; an image projecting optical system for projecting printing light beams from those ones of said micromirrors which are in said effective reflecting position, as an optical image onto a photosensitive material; a paper advancing device for advancing said photosensitive material; an active area determining device for determining an active area of said micromirror array of said spatial light modulator in accordance with a selected print size; and a driving device for driving each of those micromirrors included in said active area to tilt either to said effective reflecting position or to said ineffective reflecting position in accordance with image data, thereby to project said optical image on said photosensitive material in a size according to said selected print size.