Patent GB-915200-A (GB)
Title: Electrophotographic copying device
IPC: G03G15/22
Filed: 1959-05-28
Abstract: 915,200. Electrophotographic copying apparatus. SZEKERES, J. March 28, 1959 [May 29, 1958], No. 18188/59. Class 98 (2). [Also in Group XVI] An electrophotographic copying device, wherein a base provided with an electrophotographic film is charged, exposed to an original and developed, the image then being transferred and fixed, comprises a mechanicallymoved holding device for passing said base through various operating stations (e.g. charging, exposure, developing, transfer), said holding device having actuating means for engaging co-operating means in stations to be activated through said actuating means, the base after being charged being brought into contact with an original and exposed in synchronism therewith, separated from the original, developed, brought together with a transfer paper under pressure, and separated therefrom, the transfer paper then passing through a fixing station. Electrophotographic paper is placed on a table 2, Fig. 1, and its leading edge secured on an arm 1, Figs. 1 and 3, by means of pins 36 on a strip 30 which engage in recesses 37 in the arm 1 when the strip is pressed down and latched by a pawl 38. The arm 1 is coaxial with a drive-shaft 7 and secured to a radial arm 1<SP>1</SP> secured to the shaft. A gear sector 6 is secured to the shaft 7. On rotation of the shaft, the paper 35 passes under and is pressed down by a roller 9, and thence over a curved grounded metal plate 14 under 6000- 8000 v. D.C. wires 12<SP>1</SP>, which may be switched on only when the paper is thereunder to charge the paper. When the segment 6 engages a gear 15, the paper is passed together with an original to be copied, placed in a slot 4, beneath a belt 16 and over a transparent plate 17a for exposure to a lamp 18a. The paper and original may be pressed against the plate by a roller 53, Fig. 5, on a lever 54, the roller being engaged by a finger 56 on the arm 1<SP>1</SP> and finally raised by a cam 58 and returned by a spring. The original is delivered by stripper means 21 to a shoot 22. The paper is then passed into developer in a tank 23. The developer comprises either small glass balls mixed with a fine dry powder consisting of 96 parts of resin to 4 parts of soot, or colloidal graphite in carbon tetrachloride. The electrophotographic paper is led by hooks 3 on the arm 1<SP>1</SP> through the developer tank 23, so that the weight of developer on its upper surface presses its lower, image surface against the developer underneath. Alternatively, a metal or plastic member 60 of curved surface is immersed in the tank so that only the lower surface is in contact with the developer. The plates 14, 17a may be extended to form a complete cylinder by the curved member 60. When the segment 6 engages a gear 25, the paper is fed past a roller 26 in contact with transfer paper which is inserted in a slot 5 and delivered by stripper means 61, with the developed image transferred to it, through a slot 27 past a heating device 28 where the image is fixed. The arm 1 is returned to its original position, the drive automatically stopped, the pawl 38 released and the paper removed. In another form, Fig. 6, for use with longer electrophotographic paper sheets, two staggered gear segments 42, 42<SP>1</SP> extending through 315 degrees are mounted on the shaft 7, one at each end, so as to be driven through friction clutches, and are normally held stationary by pins 46, 47, respectively. The pin 46 is manually withdrawn to allow the segment 42, which engages the gear 15, to rotate. When the arm 1<SP>1</SP> arrives opposite the gear 25, it pushes back the pin 47 to allow the segment 42<SP>1</SP>, which engages the gear 25, to rotate. A pawl 48 is then released, and a spring-loaded yoke 49 snaps back to remove the paper 35 from the clamp so that it issues through a slot 51.