Abstract: A sheet carrying assembly comprises a platen and a carrier secured to the platen by a vacuum. The registration of the carrier on the platen is achieved by use of magnets. The magnets have fixed positions on the platen so that the carrier will always be properly positioned. In a sheet carrying system a set of interchangeable carriers is provided which have attachment means in different positions for different sheets. Such a system is particularly useful in facsimile transmission of films.

Abstract: A method and apparatus for modifying the phase characteristics of a coherent beam of radiation (7) are described. The apparatus comprises a laser (6) for generating a coherent beam of optical radiation (7). A support (1) for a record medium (1') sensitive to the radiation is provided, the beam of radiation (7) and the record medium (1') being relatively movable whereby the beam of radiation scans the record medium. First modulation means including an E/O modulator (8) and beam computer (9) is provided for modulating the beam (7) in accordance with image information. Second modulation means including an A/O modulator (10) or phase diffraction grating is responsive to a control function generated by a control function generator (11). The control function has a frequency which is repeatedly swept through a range of frequencies at a relatively fast rate to control the transmission characteristics of the grating.

Abstract: A flying spot scanner is used to expose a photosensitive surface to an intensity modulated beam of light to build up an image on the photosensitive surface.