公开(公告)号：DE2259911A1

公开(公告)日：1973-06-28

申请号：DE2259911

申请日：1972-12-07

Applicant: IBM

Inventor： DAVIDGE RONALD VAUGHN ,  LOCKLAR HENRY CLAY ,  RALSTON JAMES CLARANCE ,  RITCHIE ROBERT TYRE

IPC: G03G21/00 ,  G03G21/10 ,  G03G15/00

Abstract: 1375747 Electro-photographic printing apparatus INTERNATIONAL BUSINESS MACHINES CORP 17 Nov 1972 [22 Dec 1971] 53123/72 Heading G2H Toner remaining on electro-photographic surface 7 after transfer of a developed image is removed by an electrically biased magnetic brush 4, after the electrostatic image has been erased by light 23, and is returned to developing apparatus 1 for re-use by electrically biased magnetic brush 2. For example the toner may be returned by being attached to the surface 7 when the apparatus if not producting prints, and corotron 22, (which usually assists transfer) gives the surface a charge which attracts toner from the brush 4. Alternatively the apparatus may be made to attach bands of returned toner to the surface 7, between positions formerly occupied by images to be developed, or toner return may be carried out by separate end portions of brush 4 and surface 7, or by auger conveyors operating independently of development. Preferably the developing apparatus 1 contains magnetic carrier particles with tetrafluorethylene coats, which give a positive charge to the toner, and the cleaning apparatus 3 contains magnetic carrier particles coated with ethyl cellulose, which places a negative charge on the toner.