Patent GB-1122387-A (GB)
Title: Improvements in or relating to cyclically operable printing apparatus
Inventor: LEE RONALD HENRY
IPC: B41J19/64
Filed: 1964-12-23
Abstract: 1,122,387. Selective printers. INTERNATIONAL COMPUTERS & TABULATORS Ltd. 7 Dec., 1965 [23 Dec., 1964], No. 52176/64. Heading B6F. Type-wheel machines; type band machines; electrical signal input arrangements; line justifying; impression arrangements.-A selective printer comprising a continuously rotatable type carrier 1, which may be replaced by typecarrier bands (not shown), and constituted by a plurality of type fonts each having a set of type characters 2 of different width is provided with two pairs of pin feed tractors 6, which are displaced incrementally by a fraction of a letter space along their respective shafts 9 to 12 by a cam 17, Fig. 3 (not shown), during a succession of printing cycles necessary to complete one printing line on a record web 5 whereby on completion of the succession of printing cycles the printed line is justified. Selective printer is associated with a computer 42 having a plurality of control circuits 23 for the printing hammers 3, actuated by coils 4, each circuit including a store 24, two comparators 25, 26 associated with respective counters 31, 37, whereby coincidence between counters and comparators enables an AND- gate 27 which actuates a respective hammer 3. Store 24 comprises a set of stages 38 for storing code element signals representing the characters to be printed in a line and a set of stages 39 for storing information relating to the respective one of five printing cycles in which the respective characters are to be printed. The computer is provided with a programme enabling it to calculate in dependence upon the space required for the characters and determine the location which each character is to occupy on the second web 5. For this purpose the characters are provided with coded data pertaining to their width. The type carrier is associated with a slotted disc 28 having a set of slots co-operating with photo-electric means 29, 30 to operate the counter 31 as each one of different characters is presented at the printing line, a longer slot which co-operates with photo-electric means 32, 33 re-setting the counter to zero when a printing cycle is completed. The counter 31 sends an output signal to the comparator 25, which on coincidence enables one input line of the AND- gate 27. The pin feed tractors are associated with a similar disc 34 having a number of slots corresponding to the number of printing cycles per line a larger slot re-setting the counter 37 at the end of the printing of a line. The counter 37 sends an output signal to the comparator 26, which on coincidence enables a second input line of the AND-gate 27, which produces an output signal to actuate a respective hammer 3. During rotation of the shaft 11, which in the present case makes one complete revolution for every five revolutions of the printing drum the cam 17 of the pin feed tractors displaces the pin feed tractors 6 incrementally by a fraction of a line space corresponding to the width of the selected characters to produce the justified line at the end of the successive five printing cycles. In another embodiment (not shown) the type carrier is provided with type font spaced at alternate letter-spacing positions, and the timing disc 34, counter 37 and comparator 26 are omitted. Printing of characters takes place in two adjacent letter spaces, one being odd, the other even, in alternate printing cycles by displacing the record web from the odd to the even letter spaces. Arrangement requires half the number of hammers which print in two adjacent positions as the record web is displaced laterally. Arrangement and construction of pin-feed tractors.-Respective pairs of pin-feed tractors 6 are mounted on shafts 9, 10 and 11, 12 above and below the printing station to advance the record web 5 in line spacing direction during resetting of the counter 37 associated with the comparator 26. Pin-feed tractors 6 are adjustable transversely with respect to each other to deal with webs of varying width by means of a lead-screw (not shown). To displace the pin-feed tractors by a fraction of a letter space one member of each pair consists of a sleeve 13, Fig. 3 (not shown), sliding along 11 or 9 and a hub member 14 which slides on the sleeve 13 and carries pin wheels 15 supporting tractor band 16, Fig. 2 (not shown). Displacement of hub member 14 relative to sleeve 13 is effected by the stepped cam 17 acting on a pin 18 fast with hub member 14 which is biased by a spring 19 into contact with the cam 17 rotatable by the splined shaft 11 or 9.