ELECTROSTATIC COATING

摘要

The invention provides apparatus for electrostatically coating a pharmaceutical tablet core with powdered coating material. The apparatus comprises a first rotary drum (12) on which a core is held in electrical isolation from its surroundings but at a potential difference to earth by an electrode which contacts the core. The core is carried past a coating station B at which particles of powder having an opposite potential difference to earth are held in a tray (18). The surface of the dr um is held at the same potential difference to earth as the powder particles. The powder is attracted to the core, and not to the drum, coating the exposed surface of the core. The drum carries the coated core past a fusing station C at which a heater fuses the powder to form a continuous film coating. The core is then turned and transferred onto a second drum (12') where the other surface is coated in the same way.< /SDOAB>