THEORY OF OPERATION
CLOCK
SI
LATCH
STROBE1
STROBE2
STROBE3
STROBE4
STROBE5
COMMON
t
24V
Fig.2-6 Timing Chart
Heat buildup in the head during operation can cause print quality to degrade. To maintain uniform quality, the printer varies the energizing time (time that STROBE remains LOW) in accordance with the head temperature.
The thermal head’s surface temperature is calculated based on the resistance value of an attached thermistor. Energizing time is reduced at higher temperatures, as indicated in the figure
STROBE1, STROBE2, STROBE3
STROBE4, STROBE5,
EnergizingTime | 600 |
(tμsec) | |
| 500 |
| 400 |
Head | 300 |
|
t
t
10 | 20 | 30 | 40 | 50 |
Thermistor Temp. (°C)
Fig. 2-7 Head Energizing Control
– 25 –
