Patent GB-895332-A (GB)
Title: Improvements in or relating to rotary duplicating machines
IPC: B41L39/00
Filed: 1960-03-23
Abstract: 895,332. Xerographic printing-machines; stopping, starting &c. RITZERFELD, W., and RITZERFELD, G. March 23, 1960 [April 3, 1959], No. 10266/60. Class 100(2) [Also in Group XX] A rotary duplicating machine for printing selected lines or sections of an original text or to copy sheets comprises a rotatable carrier for the original text, a rotatable carrier for a lightsensitive surface which is chargeable electrostatically and locally dischargeable, means for charging the surface, an illuminating device controllable in accordance with a line or section selected for printing, an optical system for projecting an image of the selected line or section on to the light-sensitive surface and thereby discharging it locally to form an electrostatic image of the selected line or section, and means for moving the carrier for the light-sensitive surface relative to the optical system after each projection has been effected into a position for receiving the next projection. The original 1a, Fig. 1, is mounted on a drum I, Figs. 1 and 4, driven by a motor 3 through a one-revolution clutch 7, 8, 9, each revolution being initiated by a clutch release lever 9. A sheet 23 having a photoelectrically conducting layer is carried on a cylinder 21 mounted on a shaft 20. When the drum rotates, the cylinder 21 is rotated through gears 15-19 until the leading edge of the sheet 23 is at the exposure station, when a contact arm 26, Figs. 2 and 4, rotating with the drum, leaves a contact path 27, and a magnetic clutch. 25 between the gears 16, 17 is released. The sheet 23 is carried past a charging device 24. Rotation of the gear 19, which is keyed to the shaft 20, also causes rotation of a ratchet wheel 34 and a disc 40, Figs. 3 and 4. The wheel 34 through a pawl 35 rotates a pawl carrier 33 and also a disc 37 attached thereto, the disc 37 carrying a pawl 39 lying in a notch in the disc 40, a stop pawl 36 being brought opposite a stopping magnet 38. A torsion spring 51 is tensioned to cause the shaft 20 and the parts fixed thereto to rotate clockwise (Figs. 1, 2 and 3) with respect to the parts 33, 35, 37, 39. Release of the clutch 25 causes a contact 30 to close and energize a magnetic brake 31 which couples the carrier 33 to the machine frame. A series of contacts 13, each corresponding to a line of text and in series with a contact operated by a key 11, is arranged in the path of the arm 26 immediately after the contact path 27. When the arm 26 reaches a selected contact, lamps 43, 44 are illuminated, and the sheet 23 is exposed to light reflected from the selected line. A lamp 48 is also illuminated, and a photo-electric cell 49 causes the magnet 38 to be energized, moving the pawls 35, 36 so as to allow the spring 51 to rotate the cylinder 21 through one line space. The relative movement between the discs 37, 40 causes the pawl 39 to move out of the notch and close a contact 53 to energize a magnetic brake 54 which holds the cylinder 21. The next line position on the sheet 23 is thus ready for exposure to the next selected line. When the magnet 38 is energized, it opens a contact 58 to release the brake 54. After the arm 26 has passed all the contacts 13, it closes a contact 60 to a relay 61, and the energized relay closes contacts 62-64 and opens contacts 65, the contacts 64 completing a holding circuit to the relay, and the contacts 62 completing a circuit to a lamp 69 which discharges the non-illuminated part of the sheet 23. Opening of contacts 65 releases the brake 31. Closing of contacts 63 completes a circuit to a motor 66 which rotates the disc 37, the brake 54 being operative, to re-tension the spring 51, until the pawl 39 re-enters the notch in the disc 40, when opening of the contact 53 releases the brake 54 and the pawl 59 now transmits its movement to the cylinder 21. The latent image is thereby carried through a developing chamber 70 and the developed image transferred to a copy sheet fed between the cylinder and a counter-pressure roller 75, between fixing rollers 77, 78 and into a container. The sheet 23 is carried past a discharge chamber 79. A pivoted lever 81 opens a contact 80 under control of a cam 83 to release the relay 61. Pressing of a cancelling key 84 re-opens all contacts closed by the keys 11, otherwise repeat printing will take place. If it is required to print the same sections, such as headings, repeatedly, together with different lines in progressive sequence, use is made for the latter of a second series of contacts 85, Fig. 5, in the path of a second arm 87 mounted on the drum shaft 2 through - a ratchet, pawl and spring mechanism 91, 90, 89, 95. At the end of each drum revolution, a roller 93, held in the path of the pawl 89 by a manually operated spring finger, actuates the pawls 89, 90 to allow the spring 95 to rotate the arm 87 clockwise one line space relative to the drum. A given key 86 on a second keyboard controlling the contacts 85 thus causes printing of lines in progression. A plurality of rollers 93 may be provided to allow displacement of the arm 87 by a plurality of line spaces. A chain winding wheel 96 is provided for retensioning the spring 95. The keys 11, 86 may be replaced by electronic elements which sense pre-arranged symbols or text matter.