Optical light bead scanning arrangement

Optical light bead scanning arrangement for use in photocomposition apparatus with photosensitive material, the apparatus comprising a modulated laser for generating a modulated laser beam;

• a holder for the photosensitive material, the holder having the shape of a segment of a cylinder, whereby the photosensitive material in the holder adopts a partially cylindrical shape;
• a carriage;
• an optical image forming system and a rotatable mirror arrangement mounted on the carriage by means of which the rotatable mirror arrangement can be displaced with its axis of rotation coaxial to the cylinder axis of the holder along this cylinder axis, and wherein the laser beam, which on the rotatable mirror arrangement via the optical image forming system and which is substantially radially directed towards the photosensitive material in the holder after reflection at the rotatable mirror, scans the photosensitive material linewise as a result of rotation of the rotatable mirror and displacement of the carriage along the cylinder axis of the holder, and thereby generates a desired latent pattern in the photosensitive material, wherein the laser is arranged on the carriage and the laser beam falls onto the rotatable mirror arrangement in a direction which coincides with the cylinder axis of the holder;
• wherein the rotatable mirror arrangement makes effective scanning or exposure of the photosensitive material possible over a peripheral angle of up to approximately 180.degree. and the rotatable mirror arrangement comprises a rotatable mirror with a flat mirror surface which subtents an angle of 45.degree. to the cylinder axis of the holder;
• the axis of rotation of the rotatable mirror arrangement being above the laterally adjacent parts on the carriage;
• the laser beam being directed onto the rotatable mirror by a prism the plane of which is tilted relative to the carriage and which brings about a deflection of the light beam through approximately 180.degree..

Optical light bead scanning arrangement for use in photocomposition apparatus with photosensitive material, the apparatus comprising a modulated laser for generating a modulated laser beam;

• a holder for the photosensitive material, the holder having the shape of a segment of a cylinder, whereby the photosensitive material in the holder adopts a partially cylindrical shape;
• a carriage;
• an optical image forming system and a rotatable mirror arrangement mounted on the carriage by means of which the rotatable mirror arrangement can be displaced with its axis of rotation coaxial to the cylinder axis of the holder along this cylinder axis, and wherein the laser beam, which falls on the rotatable mirror arrangement via the optical image forming system and which is substantially radially directed towards the photosensitive material in the holder after reflection at the rotatable mirror, scans the photosensitive material linewise as a result of rotation of the rotatable mirror and displacement of the carriage along the cylinder axis of the holder, and thereby generates a desired latent pattern in the photosensitive material, the laser being arranged on the carriage;
• the photosensitive material being present in the form of a web from a supply cassette arranged at one end of the holder and constructed as a segment of a cylinder, the web being guided along the segment of the cylinder and received by a take-up cassette at the other end of the holder;
• pairs of supply rollers and take-off rollers being provided at the ends of the cylinder segment and extending parallel to the cylinder axis;
• at least the take-off rollers are driven by a motor;
• and wherein the pairs of supply rollers and take-off rollers are subdivided in their longitudinal direction into several differentially drivable and/or idler sections.