Apparatus for coating a surface with individual particles

A method of applying a layer of particles to a receiving surface, which method comprises:

• i) providing an application chamber partially bounded by the receiving surface,
• ii) utilizing an air source to blow an air stream into the application chamber,
• iii) returning air from the application chamber to an intake of the air source to form an air circulation loop,
• iv) introducing into the air circulation loop particles to be coated onto the receiving surface, and
• v) providing a particle deflector positioned in the path of the air stream, disposed such that particles impact the particle deflector prior to contact being made between the particles and the receiving surface.

An offset printing system comprising an intermediate transfer member (ITM), a coating apparatus for applying a layer of particles to the ITM, an imaging station for rendering the particles transferrable to a substrate, and an impression station at which only particles rendered transferrable by the imaging station are transferred from the ITM to a substrate to form an image on the substrate, wherein the coating apparatus comprises:

• a) an application chamber partially bounded by the receiving surface;
• b) a source of pressurized air in fluid coupling with the application chamber;
• c) an air return path forming fluid communication between the application chamber and an intake of the air source, the return path forming a portion of an air circulation loop;
• d) at least one nozzle disposed in the air circulation loop downstream from the source of pressurized air and disposed within the application chamber in a manner which will cause air supplied by the source of pressurized air to pass through the nozzle and exit therefrom as an air stream;
• e) a dosing device coupled to a source of particles to be coated onto the receiving surface and capable of controllably introducing particles into the air circulation loop;
• and,
• f) a particle deflector disposed in the path of the air stream exiting the nozzle such that particles carried by the air stream impact the deflector prior to contact being made between the particles and the receiving surface.