Patent GB-1052173-A (GB)
IPC: G03G15/10
Abstract: 1,052,173. Electrophotographic printing apparatus. A. B. DICK CO. Feb. 14, 1964 [June 5, 1963] No.6341/64. Heading G2H. In an electrographic printing apparatus, paper web 22 is drawn from roll 24 by drive roller 26 of the S-lock rollers 26, 30 and 32, and passed to the electronic printing tube 34 which produces electrostatic facsimile images on web 22 in response to signals received from a distant transmitter. Liquid developer, consisting of toner and resin binder particles in a volatile, electrically insulating, liquid, is applied to web 22 by rollers 38, 44 from trough 46, and the visible images produced are heat-fixed by hot air from blower 108. Roller 26 only engages the web when tension is provided by the main drive roller 40. From nip rollers 38, 40 the web travels to cutting device 50 whose knife 52 moves so rapidly that continuous web movement is allowed. Belt conveyer 56 carries the prints to tray 58. Trough 46 is supplied by a pump and is swingable on frame 160 together with applicator 44 away from web 22 when the drive ceases after a transmission ends. The trough also rocks about lateral bearings to equalize the pressure between rollers 38, 44 and is spring-urged upwardly by a spring link 176 which acts on frame 160 and pivots at 178 to allow the trough to be lowered for cleaning &c. Eccentric cam 202, on rotatable shaft 204 attached to frame 160, engages a follower 206 on stationary shaft 208 to depress roller 44 from roller 38 after half a revolution of the cam. A second cam 212 on shaft 204 operates switch 218 to show the position of cam 202. Cam shaft 204 is driven by a continuously-run electric motor through a clutch comprising a rotatable member carrying two pins diametrically placed which are stopped or released by an electromagnetically operated lever to engage or disengage the clutch. The same motor drives, through sprockets and chains, the roller 40 by means of clutch in which a solenoid operated pawl dis-engages a toothed clutch member to cause roller 40 to be driven. Knife 52 is carried on arms 340 extending from a shaft 338 which is sharply rotated clockwise when solenoid 314 is energized to pull down plunger 314, link 320 and pawl 324, the hook 330 on the pawl engaging a pin 332 connected to arms 336 on shaft 338. Pawl 324 is disengaged to allow biasing springs 342 to rapidly lift the knife. The operation of the knife is delayed after reception of the cut-off signal to allow the web to travel from tube 34 to the knife. For this purpose a timing device comprises two cam-operated timers 352, 354 operated by continuously driven gear 356 connected by intermediate gears to sprocket 230. The electric motor drives sprocket 230. Each timer comprises a slip clutch whereby continuous torque is applied to cams 366, 364 by gear 356, each mounted on stationary shaft 376 and urged together by spring-loaded collar 382. Hook-ended levers 394 are pivoted at 396 by solenoids 406 energized by the incoming signal to disengage a lever from a notch in the corresponding cam. The cam then rotates once at the lever re-engages, this rotation operating a switch 420 to operate the knife. A second signal received before timer 352 has completed its cycle is routed to the solenoid 406 of second timer 354. Further timers may be provided if the apparatus requires greater capacity than for two cut-off signals. The routing means is a selector switch controlled by a two-level cam 368.