Patent GB-936551-A (GB)
Title: Improvements in or relating to rotary duplicating machines
IPC: B41L11/00
Filed: 1961-11-15
Abstract: 936,551. Copying documents. W. RITZERFELD, and G. RITZERFELD. Nov. 15, 1961 Dec. 1, 1960], No. 40847/61. Class 100 (2). A rotary duplicating machine for printing selected lines from a printing master sheet 1 on to a copy sheet 16 by controlled co-operation of a printing drum 3 carrying the master sheet and a counter pressure roller 33 movable into engagement therewith by an electromagnet arrangement 23, 26 arranged for energization by a photo-electric sensing device 6 adapted to sense markings such as 4, 5 provided on or movable with the master sheet 1 comprises a photo-electric pulse generator 13 having a light chopper 8 arranged for synchronous rotation with the printing drum 1, the chopper 8 being arranged between a fixedly mounted light source 13a and a photo-electric cell 13b and having three openings 12 for each line of printing on the master sheet and a pulsecounting device 14 which responds to the pulses of the generator and gives one pulse per master sheet line to a transfer register 7 having a plurality of bi-stable stages S1-S22, one being allocated to each master sheet line. The relevant bi-stable stage receives a statechanging pulse from the sensing device 6 in the presence of a sensed marking 4, 5 before the pulse derived from the generator 13 has reached the relevant bi-stable stage and a pulse timing and amplifying arrangement 21, 22, 24, 25 effects control of the electromagnet arrangement 23, 26 in the rhythm of the emergence of pulses from the transfer register 7 as a result of information supplied in the form of the statechanging pulses. A transfer pulse may be derived by setting a key allocated to a bistable stage, e.g. S3, in addition to those derived by sensing the markings 4, 5 on the master sheet. An auxiliary transfer register 15 is provided to allow for the angle of rotation between the position of the first printing line of the master sheet 1 when at rest and the line of printing between the drum 3 and the roller 33 and comprises as many bi-stable stages as the number of lines which could be provided on an equivalent angular length of the master sheet, the arrangement being such that the transfer pulses pass through the auxiliary transfer register 15 after leaving the main transfer register 7 and only then cause the creation of control pulses for the electromagnet arrangement. A branching network is provided at 19 so that the output pulses of the register 15 are fed to the bi-stable stage of the register 7 which corresponds to the final master sheet line in addition to the control means of the electromagnet arrangement. The electromagnet arrangement comprises two electromagnets 23, 26 which are operable alternately and are associated with armatures 29, 29a respectively which are connected to a lever 32 pivoted at 35 by means of a rod 31, fork members 28, 28a, and links 30, 30a. The counter pressure roller 33 is mounted on a shaft 34 on one end of the lever 32 and energization of either electromagnet causes the roller 33 to be swung against the drum 3 for printing a line of the sheet 1.