| 摘要 |
Proportional spacing of characters, for example by a laser-xerographic printer, is achieved using a character generator memory, for example a random access memory (RAM), to store the characters of a font in a plurality of variable-size binary matrices. Each column includes at least one parity bit and at least two pitch bits or end of character (EOC) bits. After a character matrix is selected for printing: the columns are transmitted sequentially from the RAM, the bit patterns are decoded as valid and invalid EOC indication signals or as valid and invalid NON-EOC signals, and the parity of each column is checked. Also, stop printing circuitry inhibits operation of the dot matrix printer when the parity checker indicates no error but the pitch bit decoder derives an invalid EOC or NON-EOC SIGNAL.
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