| 摘要 |
1458023 Control of printers GENERAL ELECTRIC CO 13 Dec 1973 [13 Dec 1972] 57731/73 Heading G4H A printer control system includes means 14, 23, 16 for controlling the rate at which data is fed from a source 1 to a printer 6. Source 1 (e.g. a CRT terminal, computer or tape store) delivers data faster than it can be processed by printer 6. This may be a belt printer as in Specifications 1,228,280 or 1,219,242 and includes a recirculating register 130, Fig. 4 (not shown) storing printable characters and non-printable codes such as line feed LF, vertical tab VT, form feed FF, and a column counter (152) determining the position along the print line where a printable character is to be placed. The counter is incremented (STROBE 68) when a printable character is stored or when SPACE (not stored) is detected. Signals from SPACE and LF, VT, FF detectors 18, 12 control a timer 14 which enables or blocks a NAND gate 16 in such a way that data transmission from source 1 to printer 6 takes place after a predetermined delay following a printable character, and after no delay following SPACE. A further detector and timer 23 blocks gate 16 for a variable time (possibly longer than the above delay) upon recognition of a non-printable, non-SPACE code, e.g. LINE-FEED; gate 16 is blocked if a new LF (signal 20) occurs while there is a LF (signal 21) in memory awaiting execution. |
