Described herein is an electrostatic spray coating machine of the type which has a plural number of supporters (31) at intervals around the circumference of a housing (2) as electrode retainer rods for holding external electrodes (32). Each supporter (31) is formed with an oblique surface (31A) at the fore end thereof to provide a concealing projection (31B) on the inner side of the fore end of the supporter (31). As a result, when seen from the rotary atomizer head (5), the discharge distance (H') betweewn the fore end (32A) of each external electrode (32) and the rotary atomizer head (5) is increased to permit application of a higher voltage to the external electrodes (32).

A rotary atomizer including a bell element having a paint tube, a deflector having a conical distribution surface opposite the paint tube outlet, including a tip portion within the paint tube, directing paint to a paint overflow surface through an annular conical channel adjacent the outer edge of a nonconductive end face, an annular electrostatically charged surface surrounding the outer edge of the end face generating an annular electrostatic field and an axial electrode having a sharp distal end in the plane of the annular electrostatically charged surface generating a second axial electrostatic field.

A rotary spray atomizer for applying electrically conductive paint, in particular water-based paint, to surfaces, includes a housing. A spray head is fitted on front of the housing for receiving a supply of paint and discharging the supply of paint in a spray mist as a result of rotation. A motor is disposed in the housing for rotary actuation of the spray head. At least two electrode holders are disposed along a concentric circle and extend towards the front parallel to a longitudinal axis of the housing. Electrodes are each accommodated in and protrude from an end of a respective one of the electrode holders. High-voltage sources constructed as a cascade are each plugged into a respective one of the electrode holders for receiving a low-voltage current, feeding one of the electrodes and causing the electrode to generate an electric field applying the spray mist discharged by the spray head to an application surface.

A process for coating a substrate such as a photoreceptor is performed by delivering at least two fluid streams to a bell of a rotary atomizer, combining the fluid streams substantially at the bell of the rotary atomizer such that the bell atomizes and mixes the fluid streams into a substantially homogenous atomized mixture, and depositing the mixture onto the substrate in the form of a layer on the substrate. The process is useful for depositing a plurality of different substances, such as two charge generating pigments, on the surface of a substrate such as a photoreceptor. Because the substances are combined substantially at the bell of the rotary atomizer and subsequently dried or polymerized, different substances can be incorporated into a single layer on the substrate that would normally not be combinable due to interaction between the plurality of substances such as agglomeration.

A spray apparatus for coating material, in particular for coating powders, contains a spray outlet spraying the coating material, a shaping air outlet in the form of a plurality of holes shaping the spray jet and an ambient-air passage radially configured between the spray outlet and the holes to aspirate ambient air by means of the flow suction effect of the spray jet and/or of the shaping air flow.