3-22
3.5.2 Calculation of Printing Energy
The printing energy "E" can be calculated using equation (4) as the appropriate printing energy is different
depending on each specified thermal paper and the temperature of the thermal head.
Equation (4):
25
X
T
C
T
25
E
E
-
-
E :
Printing
energy
E
25
:
Standard printing energy
T
C
: Temperature
coefficient
T
X
:
Temperature detected by thermistor (°C) *
*: Measure the temperature using the resistance of the built-in thermistor on the thermal head.
For the thermistor resistance value at T
X
(°C), see Section 3.5.8 Temperature Characteristics of the Thermistor.
Table 3-16 Standard Printing Energy and Temperature Coefficient
Specified thermal paper
Standard
printing energy
(mJ)
Temperature
coefficient
(T
C
)
Nippon Paper
TF50KS-E2D
0.2853
0.002803
PD150R
0.3558
0.002432
Oji Paper Co., Ltd.
PD160R-N
0.3238
0.002245
Mitsubishi Paper mills limited
F220VP
0.3374
0.002683
T
X
≧
25
℃
0.3061
0.003542
AF50KS-E
T
X
≦
25
℃
0.3061
0.002260
Jujo Thermal
AP50KS-FZ
0.3237
0.003306
Mitsubishi Hi-Tech Paper
F5041
0.3376
0.002703
T
X
≧
25
℃
0.3503
0.004436
Papierfabrik August Koehler AG
KT55F20
T
X
≦
25
℃
0.3503
0.001339
KSP
P300
0.3254
0.003478
3.5.3 Adjustment of Thermal Head Resistance
The adjusted resistance "R" can be calculated using equation (5) to adjust the thermal head resistance as a
voltage drop is caused by wiring resistance.
Equation (5):
H
2
SA
c
C
i
H
R
)
N
×
)
r
+
R
(
+
R
+
R
(
=
R
R
H
:
Thermal head heat element resistance
180.0 (
Ω
)
R
i
:
Wiring resistance in the thermal head
9.0 (
Ω
)
*1
R
C
:
Common terminal wiring resistance
in the thermal head
0.279 (
Ω
)
r
C
:
Wiring resistance between Vp and GND (
Ω
)
*2
N
SA
:
The number of simultaneously activated dots
*1 : The value at Vdd =3.3V. When the value at Vdd =5.0V, Ri becomes 6
Ω
.
*2 : The resistance is a serial resistance of the wire and switching circuit of relay between control terminal and power
supply.