Photohead with flashing beam

Abstract

A photoplotter for use in exposing graphics or artworks on a photosensitive surface by directing a small beam of light onto the surface and moving it relative thereto has an output beam which is repetitively flashed as it is moved over the surface to expose a line. The flashing light beam is produced by intercepting a stationary beam with a cyclically moving mirror to periodically sweep it across a light accepting window, the light energy received by which is directed to the photosensitive surface. The cross-sectional size of the output light beam may be varied to vary the size of the light spot which it creates on the photosensitive surface and to therefore vary the width of the exposed line, and changes in the character of the output beam may be made in accordance with changes in the size of the spot and with changes in its speed relative to the photosensitive surface in order to obtain a desired exposure of all portions of the exposed lines. The photohead may also be designed to deliver a beam of selectively variable color to the photosensitive surface for exposing colored graphics on a color sensitive surface, and two or more beams may be combined into the single delivered output beam to produce a beam of desired color or intensity.

Dependencies are inferred from the claim text.