Patent GB-968850-A (GB)
Title: Electrophotographic photocopy matchine
IPC: G03G15/09
Filed: 1960-11-16
Abstract: 968, 850. Electrophotographic processes. AMERICAN PHOTOCOPY EQUIPMENT CO. Nov. 16, 1960 [ Nov. 16, 1959], No. 39297/60. Heading G2H. Original and electrophotographic copy sheets 40, 41, Fig. 1a, are fed through inlet slots 34 and 35 respectively to rollers 61, 62, Fig. 2, and 81, 82. The copy sheet includes a paper backing having a sensitive coating, e.g., in the form of zinc oxide and binder. The copy sheet is electrostatically charged in a charging unit 84 having wires 85 and 86 connected to a high voltage supply to set up a corona discharge and apply in the case of zinc oxide coated paper on all-over negative charge. Rollers 91, 92 feed the charged copy sheet to deflector plates 98 which deflect the sheet upwardly through approximately 90 degrees to engage rollers 101, 102 which feed the sheet to an exposing station 51. The copy sheet is guided by a belt 121 against a transparent window 120 where it receives a projected image from the original at exposing station 50. The copy and original sheets are fed in opposite directions at the same speed during exposure. The original is illuminated by a pair of high intensity lamps 151, 152 disposed end to end and backed by a reflector 155. The lamps are cooled by a blower 170 Fig. 3 (not shown) which withdraws air from housing 140 Fig. 2. Light travels from point p along optical path 198 and is reflected by mirror 197, Fig. 9, (not shown) in mounting 190 carrying lens 195 and 196. A mask 200, Fig. 2, has curves 201, 202, Fig. 11 (not shown) which equalize the light falling on the exposure station 51. The latent electrostatic image formed on the copy sheet at the exposure station is developed by developer unit 54 which applies toner to charged areas. A bin 210, Fig. 12, carries a mixture of toner and iron particles 212. Alternatively, the toner particles may be magnetic iron or nickel which receive a charge opposite to the image areas by induction. The copy sheet enters slot 216 normally sealed by fabric flap 217. A fluted magnetic roller 211 rotates in bin 210, such that ridges 218 acquire brush like tufts of toner and iron mixture. A bar 225 of opposite magnetic pole to the roller 211 produces parallel lines of flux 227. A barrier 215 of aluminium or other non-magnetic material is interposed between the bar 225 and roller 211. Toner and iron particles are constantly mixed by oppositely rotating members 331, 332 to achieve uniform development of copy sheets. Toner is replenished from a perforated container 340 vibrated by an electromagnetic 350. Alternatively, the container 341 may be of flexible plastic, e. g., polyethylene with means to squeeze at least one wall. Developed copy sheets are fixed by fixing apparatus 55 having heat lamps 361, 362 having a cylindrical quartz envelope and filament operated at such a temperature that the output is partially infra-red. The black toner is melted on to the copy sheets which in the white non-image areas reflects the infra-red radiation. An evacuated chamber 370 connected to blower 70 Fig. 3 (not shown) holds the copy sheets flat against face plate 371 Fig. 12. In the absence of a copy sheet heat is removed through the air stream through chamber 370. Rollers 375, 376 remove the developed and fixed copy sheets. Rollers for feeding the original and copy sheets are contained by removable sub-frames 405, 406 Fig. 6a (not shown), the sub-frames being secured to main frame members 401, 402 Fig. 4 (not shown) by fasteners 411, 413, Fig. 6a (not shown) and to entry member 420 by fasteners 421, 423. The feed rollers, e. g., 61, 62 and 81, 82, are driven by motor 440 Fig.5 (not shown) through a main drive shaft 441 Fig. 6 (not shown) through driving belts, e. g., 443 and gearing. The apparatus is controlled by control circuit Fig. 19 (not shown) having a sheet actuated detector switch 480 which closes the circuits to the source 89 supplying the charging device and illuminating lamps 151, 152.