3.4 THERMAL HEAD
The thermal head consists of heat elements and a thermal head driver that drives and controls the heat
elements. For the print data entered through the DI terminal, print is "High" and non print is "low".
The data from the DI terminal is transferred to the shift register at the rising edge of the CLK signal.
The data is stored into the latch register by making
LAT
signal "Low" after one line data is transferred. The
heat elements are activated by making DST signal "High" in accordance with the stored print data.
Simultaneously activated dots is 45 dots.
3.4.1 Structure of the Thermal Head
Figure 3-6 shows the thermal head block diagram when driving the printer.
Table 3-9 shows the relationship between DST terminals and activated heating elements.
Vp
DI
CLK
LAT
TH
GND
Vdd
DOT 1
DOT
384
DST
DOT
64
DOT
65
DOT 128
DOT 129
DOT 192
DOT 193
DOT 256
DOT 257
DOT
320
DOT
321
Heating Element
Output Driver
LAT Register
Shift Register
Thermistor
Figure 3-6 Thermal Head Block Diagram
Table 3-9 DST Terminals and Heating Elements
Block DST
Number
Heating Element
Number
Dots / DST
1
1 to 64
2
65 to 128
3
129 to 192
4
193 to 256
5
257 to 320
6
DST
321 to 384
384
3-15
