GB1474117A - On-the-fly printer with shortened print cycle - Google Patents

Abstract

1474117 Control of printers SPERRY RAND CORP 10 Sept 1974 [12 Sept 1973] 39415/74 Heading G4H An "on-the-flag" printer incorporates means for shortening the print cycle time. The printer shown schematically in Fig. 1 is conventional apart from the presence of a memory 13. In operation, 8-bit parallel binary signals representing the available characters in their order along or around a moving type carrier are entered in a memory 14. Signals representing data to be printed (printable characters and non-printable characters not on the type carrier) are entered in a memory 12 and the contents of 12 are compared at 16 with the contents of 14 for every coincidence position of characters on the type carrier and the print hammers. Successful comparisons result in signals 17 which decrement a counter 19 preset to the maximum number of printable characters; decoder 20 detects a count of zero in 19 to produce a "print end signal" 15. Memory 13 contains 256 storage locations. When the binary signals are sent to memory 14, a "1" is stored in the corresponding locations in memory 13. The binary signals sent to memory 12 then address their corresponding locations in memory 13; if a "0" is stored at an addressed location (i.e. the signal sent to memory 12 has no counterpart in memory 14 and is thus non- printable), a signal 23a decrements counter 19. Thus, when printing begins, the count in 19 corresponds to the number of printable characters in memory 12, rather than the total number of signals stored therein, so that the "print end" signal is produced without unnecessary delay.