| 摘要 |
<p>A hollow tubular shaft, containing optical elements for use in a helical scanning facsimile transceiver, is supported horizontally by air bearings and translated linearly along its major axis through cylindrical reading and writing stations by means of a pneumatic cylinder and piston coaxial with the shaft. An integral reaction-powered air motor provides shaft rotation, and laser beams perform the reading and writing operations, both of which may take place within the same apparatus or either one of which may be executed at a location remote from that of the other. The reading station contains an optical encoding pattern enabling continuous control of the position of the radiation beams relative to the indicia being read, and an electronic memory facilitates the temporary storage and manipulation of information to be recorded by the writing station. A fail-safe system prevents damage to the scanning mechanism in the event of interruption of the pneumatic or electrical supplies. The apparatus finds particular utility in the production of printing plates for use in Graphic Arts reproduction processes.</p> |
