Patent GB-1275950-A (GB)
Title: Facsimile transceiver apparatus
IPC: H04N1/06
Filed: 1969-09-03
Abstract: 1275950 Facsimile transceiver apparatus XEROX CORP 3 Sept 1969 [11 Sept 1968] 43640/69 Heading H4F In a facsimile transceiver documents or copy sheets are advanced through a semi-cylindrical passageway between inner and outer platen assemblies 500, 550, Fig. 2, past a rotating turret assembly 700 containing optical scanning means for generating electrical signals representing information on a document when the apparatus is in the transmitting mode and electrographic recording means for electrostatically charging a copy sheet according to a pattern dictated by incoming electrical signals in the receiving mode. For receiving mode operation a developing station 900 is provided to render the electrostatic pattern visible by means, for example, of iron filings mixed with electroscopic toner particles, and at a fusing station 950 the toner material is fused to the copy sheet. Electrographic processing.-The electrostatic pattern is supplied to the copy sheet by two diametrically opposed recording heads (708, 709), Fig. 14 (not shown), on the rotating turret 700. Each head includes a stylus (740) carrying a high voltage, which is movable into an operative position under the control of a solenoid (SOL 750) receiving the incoming electrical signals. After the complete copy sheet has been subjected to recording it is advanced to the developing station where it comes into brushing contact with the iron filings/toner mixer borne magnetically by a rotating drum 907, Fig. 11. The mixture is supplied to the drum 907 by two concentric helical screw conveyers 903, 905, and the desired magnetic field distribution about the drum 907 is obtained by means of fixed magnets 909, 909<SP>1</SP> within the drum 907. An electrically charged platen 916 behind the copy sheet ensures that the back ground of the sheet remains free of developer material. The copy sheet is next advanced between heated rollers 952, 954 covered with material 958 such as Teflon (Registered Trade Mark) to prevent toner offset and also covered with silicone oil supplied by a further roller 975, and the toner is here fused on to the copy sheet to render it permanent. Sheet feeding.-Documents 104, Fig. 2, or copy sheets 105 are supplied from piles on respective trays 101, 102 by pivoted automatic feeders 200, 400 including friction rollers to separate and advance individual sheets from the piles. The document feed assembly 300 includes a roller (203), Fig. 9 (not shown), stating in a direction such as to return any sheets fed inadvertently with the upper sheet to the pile. Photo-cell detectors are used to detect the leading edges of sheets in both feed assemblies and to initiate operation of subsequent feed stages. Once the document or copy sheet has reached the passageway between the platens 500, 550, Fig. 2, it is advanced rapidly to the scanning station by a series of rollers extending into the passageway through the platens. At the scanning station it is advanced intermittently by a further series of rollers on an assembly 650 while scanning or recording programmes, and when it is completed a clutch is caused to operate which results in a rapid feed of the sheet to a position beyond the scanning station. From this position it is withdrawn to a discharge tray 103 either via the developing and fusing stations 900, 950 in the receiving mode, or directly in the transmitting mode, separate feed assemblies 850, 800 being provided for these alternative paths. Selection of the desired path is effected by pivoting a deflector plate 840, Fig. 11, adjacent the platens 500, 550 to one of two positions. Circuitry.-The electrical signals containing the information for transmission or from reception is in binary code form, and a buffer store 118, Fig. 14, is provided to regulate the rate at which information is passed to the recording stylus 740, Fig. 15 or to the transmit acoustic coupler 129. A unique code sync. word is used to indicate the start of each new line of information. Facilities are provided for interconnecting two remote transceivers by coaxial line link rather than by telephone link, and also for enabling the transceiver to be used in conjunction with other transceivers of different types.