Thermal printing system - has heating element period determined by load and internal resistance of battery

摘要

A thermal printer has an array of single heating elements (R11-RmN) arranged in segments (Sg1-Sgn) along the length of the paper (11). Each element receive an input from a NAND gate switch (S11-SnN). Individual data bits are provided by a serial to parallel shift register (7) with the outputs transferred to a latch memory (5) coupled to the heating element drive stages. The signals are gated through to the heating elements by a strobe pulse (28) that has a period based upon the load and battery (2) state. The internal battery resistance determines the print voltage that is set by selection of the strobe period. ADVANTAGE - Maintains uniform print density.