Patent GB-1108653-A (GB)
Title: A system for transporting and refining particulate material
IPC: G03G15/06
Filed: 1966-07-06
Abstract: 1,108,653. Separating particulate material. BORG-WARNER CORPORATION. 6 July, 1966 [12 July, 1965], No. 30394/66. Heading B2P. [Also in Division G2] In an electrostatic printing system in which a paper web has discrete areas specifically charged to represent a latent information denoting pattern, the web is passed over a roller 37 and around an anvil 36 to come into contact with a mass 100 of conductive ink particles of predetermined size in an upper chamber 35 of an ink reservoir 10. Some of the ink particles are attracted by electrostatic force to the charged web areas and are retained thereon as the web is pulled upwardly out of the ink reservoir. Ink particles which may adhere to the uncharged areas of the web are removed therefrom by means of a suction head or sniffer 41 coupled via a conduit 42, a cyclone separator 44, a conduit duit 48, a filter 50 and a conduit 51 to a pump 52 which discharges clean air to atmosphere, the heavier ink particles of desired size separated in the cyclone being collected in a box 46 for re-use in the ink reservoir 10 and the lighter unwanted ink particles leaving the cyclone being separated out in the filter 50. The web then passes between fixing rolls 38, 40 where the ink particles are firmly pressed into the charged areas of the web surface to provide permanent record of the information. Ink particles entrained from the mass 100 by the air current created by the upward movement of the web are separated out and caused to fall back into the mass by air deflector blades 114 and by an upturned lip 115 of a guide plate 98. Ink particles in excess of the desired amount in the chamber 35 drop through overflow openings 101 in a wall 97 of the chamber and collect as a mass 104 in a chamber 19 in the lower portion of the ink reservoir 10. From the chamber 19, the particles are drawn via a conduit 11 through a Venturi unit 12 operated by air supplied by means of a pump 68 and are carried in an air current along a conduit 16 to a cyclone separator 18. Fine. light impurities, e.g. paper debris, dust and fragmented ink particles, are discharged with the air from the cyclone via conduits 20, 21 through a bag-filter unit 60, the clean air being returned via a metering cock 63 and a further filter 66 to the pump 68. The remaining heavier particles leaving the cyclone 18 through a conduit 22 are separted by means of a vibrating screen unit 23 into unwanted coarse impurities, e.g. agglomerated particles, which are discharged into a box 33, and into ink particles of the desired size which are fed into the upper chamber 35 of the reservoir 10 via a conduit 34. At the start of an operation. a solenoid valve 47 in a conduit 24 leading from the box 46 below the cyclone 44 is actuated to feed the ink particles, previously collected in the box, into the chamber 35. A "low ink" signal unit is provided in the lower chamber 19 at 76. The anvil 36 may be displaced in the direction of the arrows 95, 96 to permit threading of the web into the reservoir 10 at the start of an operation, a signal unit 82 being provided to indicate that the anvil has been returned to its working position in which the web is in contact with the ink particles.