PROPORTIONAL WIDTH PRINTING SYSTEM

摘要

A proportional width printing system is provided with tab means enabling it to print in columns.
Characters in an output line buffer (72) are supplied to a character generator address register (74) which addresses the character generator memory to provide character generating signals to the printer. When each character has been generated an end of character detector (82) initiates the generation of the next succeeding character in the line.
To enable the printer to print in columns a tab memory (88) stores the address of the left margin of each column and is addressed by a tab memory address counter (86) synchronised with the printer scan. A tab bit indicating the first character of a column generates a tab signal in the character generator address register (74) which prevents the end of character detector (82) initiating the generation of the next character and stops the incrementing of the character generator address register until the tab memory (88) indicates that the beginning of a column has been reached.
The character generator address register (84) may generate a signal identifying the required tab position, and this may be compared with a corresponding signal stored in the tab memory (88) by a comparator (90) to provide the signal for initiating the generation of a character.