Method and apparatus for producing uniform small portions of fine powders and articles thereof

Abstract

Uniform portions of fine powders are deposited on a substrate by electrostatic attraction in which the charge of the electric field and polarity of the charged particles are varied repeatedly to form a buildup of powder on the carrier surface.

1 - 42 . (canceled) 
   
   
       43 . An apparatus for depositing onto a substrate controlled quantities of particulate material from a source of said material, said apparatus comprising a charge generator for applying a predetermined electrostatic charge to particles of said material upstream of a deposition zone in which said substrate is located, and a controller for repeatedly varying the polarity of charge being applied to said material and to said substrate. 
   
   
       44 . The apparatus according to  claim 43 , wherein the controller comprises a switch oscillator. 
   
   
       45 . The apparatus according to  claim 43 , wherein the controller includes a clock for varying the polarity of charge over time. 
   
   
       46 . The apparatus according to  claim 43 , wherein said controller is adapted to switch polarity applied to said powder and to said substrate in synchronization. 
   
   
       47 . The apparatus according to  claim 43 , and including sensors for measuring the mass flow of aerosol particles that pass into and out of the deposition zone. 
   
   
       48 - 73 . (canceled)