Specifications

3-21
3.6.3 Adjustment of Head Activation Voltage
Adjustment of head activation pulse width due to changing the head activation voltage is to be in
accordance with equation (5). The adjustment method differs if the head drive voltage (Vp) is 5.5 V or
more or under 5.5 V.
If head temperature is above -5°C
Equation (5):
(5.5 V or more)
V=Vp × 1.2 - 1.8
(under 5.5 V)
V=Vp × 1.4 - 2.9
Vp: Head activation voltage (V)
If head temperature is below -5°C
More than 5.5V : V = Vp ×1.2 - 1.8 + T × 0.01
Less than 5.5V : V = Vp ×1.4 - 2.9 + T × 0.01
T: Thermistor detection temperature (°C)
3.6.4 Adjustment of Head Resistance
Adjustment of head resistance is to be in accordance with equation (6). Due to wiring resistance there is a
drop in voltage.
Equation (6):
RH: Head resistance 178.5 (Ω)
25: Wiring resistance in the thermal head (Ω)
R
C
: Common terminal wiring resistance in the thermal head: 0.1 (Ω)
r
C
: Wiring resistance between V
P
and GND (Ω)
1
N: Number of dots driven at the same time
1
This resistance is the resistance of the wire used between the FFC terminal of thermal head, the power supply,
the resistance of switching circuit of relay, etc.
( RH + 25 + (R
C
+ r
C
) × N )
2
R= 
RH