Patent GB-1279129-A (GB)
Title: Document feed apparatus
Inventor: HOWARD A
IPC: G03G15/00
Filed: 1969-11-18
Abstract: 1279129 Sheet feeding and delivery apparatus XEROX CORP 18 Nov 1969 [20 Nov 1968 4 Dec 1968 (2)] 56395/69 Heading B8R Apparatus for feeding sheets to and away from a work-station such as the platen 6 of a xerographic copying machine 5 to make copies from the sheets comprises means for feeding the sheets one by one from a pile 24 in a tray 26, to the platen 6 and then returning them to the tray on to the top of the pile 24, a device being provided which separates the returned sheets from those being fed so as to prevent feed of the returned sheets after the last sheet of the pile has been fed. The device comprises a bar 30 carried by two pivoted arms which can be operated by a solenoid 35 to move the bar to a position where it no longer supports the returned sheets. In operation, upon receipt of a starting signal from the machine, a driving motor is energized and clutches actuated to cause a separator roll 14, or a separator belt, and feed rolls 40, 49 to be driven at a relatively slow speed to feed a sheet forward from the tray. Spring-pressed rollers 42, 48 co-operate with the rollers 40, 49, the roller 42 co-operating with the roller 40 as described later to prevent the feed of more than one sheet, and the roller 48 at this time being rotated by roller 49. When the leading part of the sheet is sensed by a photoelectric device 133<SP>1</SP>beyond the rollers 48, 49, electrically operated clutches disconnect the drive to the rollers 14, 40, 49, and cause roller 48 and a light-reflective belt 58 to be driven at a relatively fast speed to feed the sheet on to the platen 6, a freewheel device in the drive to the roller 49 allowing that roller to be rotated by the roller 48 at the faster speed. Timing devices allow the belt 58 to be driven for a sufficient time to transport the sheet on to the platen with its trailing edge beyond a registering stop 51, Fig. 3, on a pivoted member 50. The stop 51 is raised to an operative position by an electromagnet 55 and the direction of movement of the belt 58 is reversed to register the rear edge of the sheet against the stop, the belt then sliding over the surface of the sheet. Copying now takes place and when completed, a signal from the machine 5 causes the de-energizing of electromagnet 55 so that the stop 51 is retracted and the belt 58 causes the sheet to move over the upper surface of wedge-shaped members 70 into engagement with rollers 65, 66 which together with rollers 65<SP>1</SP>, 66<SP>1</SP>feed the sheet through guides 73, 74 back to the tray 26. Sensing of the presence of the copied sheet by a photoelectric device 134<SP>1</SP>operates clutches to terminate the reverse drive to the belt 58, and to drive the belt and rollers 48, 49 at high speed to feed the next sheet into the machine. The sheets may be registered at their leading edges against a stop at the left-hand end, Fig. 1, of the platen 6, and the belt 58 may be stationary during the copying operation. When the rear edge of a sheet which is being fed to the platen 6 passes the detector 133<SP>1</SP>,clutches are actuated to cause the rollers 14, 40, 49 to be driven to feed the next sheet forward in readiness for its transport to the platen 6. Pressure members 75, manually raisable, prevent sheets from falling out of the tray 26 and maintain the lowermost sheet in contact with separator roll. Detecting exhaustion of pile.-When the last sheet has been fed from the pile 24, a beam of light from a source 135<SP>1</SP>actuates a photoelectric device on the bar 30 to stop the driving motor after an interval sufficient to allow the last sheet to be copied and return to the tray 26. If, however, a further set of copies is required, control means are set to actuate solenoid 35 to lift the bar 30 so as to allow the pile of sheets to drop into position to be again fed through the machine. Preventing feed of more than one sheet.-A direct drive to the roller 42 of roller pair 40, 42 through a one-way clutch tends to rotate the roller 42 in a direction reverse to the feeding direction. If no sheet or a single sheet is between the rollers 40, 42, the roller 42 is driven by friction from the roller 40 in the feeding direction, the one-way clutch permitting this to take place. Should two sheets pass to the bight of the rollers 40, 42, the friction effect is reduced, and the roller 42 is rotated reversely by its direct drive to return the upper sheet to the pile.