| 摘要 |
1,036,983. Printing-apparatus. ELECTROSTATIC PRINTING CORPORATION OF AMERICA. March 16, 1965 [Aug. 3, 1964], No. 10986/65. Heading B6C. Apparatus for printing on a sheet 16 comprises means 14 for applying a potential between a screen electrode 10 and a rear plate 12, a brush 24 adapted to be loaded with an electroscopic powder and rotated over the surface of the screen electrode 10, and a member 30 having its surface made of a material having triboelectric properties and arranged in frictional contact with the brush so as to transfer the powder thereto from a reservoir 32. The member 30 may be in the form of a longitudinally grooved roller or an endless belt, Fig. 5 (not shown), and its surface is advantageously of polytetrafluoroethylene or a methacrylate. This surface picks up a uniform layer of powder and maintains the brush uniformly loaded irrespective of the size of the image printed. The periphery of the brush is preferably of mohair pile fabric. The powder in the reservoir is agitated by a brush 36, by air pressure, or by a vibrating device using a piezo-electric element. The powder supply apparatus is reciprocated with the brush 24 by a rack drive, and the supply train may include a pair of idler rollers similar to the roller 30 and in contact with the brush. The assembly comprising the screen electrode, the sheet 16, and the plate 12, may have any desired orientation.
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