GB898123A - Improvements in or relating to rotary duplicating machines - Google Patents

Abstract

898,123. Printing machines. RITZERFELD, W., and RITZERFELD, G. Nov. 5, 1959 [Dec. 10, 1958], No. 37564/59. Class 100(2) Tripping-arrangements; rotary machines. A rotary duplicating machine comprises a printing drum carrying a lithographic master sheet, a first counter-pressure roller of approximately the same diameter as the drum and having means fcr fixing thereto the leading edge of a copy sheet, said roller co-operating with the drum for printing the entire master sheet on a copy sheet, and a second counter-pressure roller which can be temporarily, rendered operative for printing a predetermined line or section of the master sheet on a further copy sheet. For printing the whole text from a lithographic master sheet 2, Figs. 1 and 3, secured to a printing drum 1, a copy sheet 21 is fed from a stack 23 to a counter-pressure roller 13 carrying a rubber blanket 14 and geared to the drum, grippers 20 for the sheet being actuated by a stationary cam 27, and sheet being delivered to a container 28. For printing selected lines of text, a copy sheet is fed between the drum and a second counter-impression roller 29, which is carried on levers 31 pivoted at 32, and moved against the drum at selected times by electromagnets 36. The roller 29 is geared to the drum, the gear teeth engaging to rotate the roller, even when the latter is moved away from the drum as far as permitted by' a stop 39. A sheet 51 is placed on a table 52 having a cut-out 68 for the roller 29 to pass through, and rests against an abutment 53. On pressing a lever 48, a switch 54 is opened to de-energize a magnet 55, raise the abutment 53 and close a sheet passage 58. At the same time, the lever 48 releases a pawl 45 pivoted on a contact arm 44 freely mounted on a shaft 43 to which is secured a disc 42, the pawl engaging a notch in the disc and rotating the arm 44, a contact 63 on which sweeps over a series of contacts K1-K19, each contact in series with a key T1 to T5 and so on. When the contact 63 engages a contact K whose key T is closed, a circuit is completed for a small current to an electrode control device 62, and a larger current from a rectifier 64 passes to the magnets 36. The contact 63 then engages a rail 65 and the roller 29 is again lowered to eject the sheet 52 into a container 66.