Seiko LTP1245R-C384-E, Technical Reference, Page: 34 / 74

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3.6 CONTROLLING THE HEAD ACTIVATION (DST) PULSE WIDTH
3.6.1 Calculation of Head Activation Pulse Width
Head activation pulse width is calculated using the following equation (3).
To execute high quality printing using the LTP1245, the value that is calculated using the following
equation (3) must be adjusted according to the printer’s installation environment. Calculate each value
used according to the steps in
Sections 3.6.2 to 3.6.6 and apply the pulse width with the t value that is
obtained by substituting each value into the equation (3).
Printing using too high voltage or too long pulse width may shorten the life of the thermal head.
Equation (3):
t : Head pulse width (ms)
E : Standard applied energy (mJ) See Section 3.6.2 .
V : Applied voltage (V) See Section 3.6.3 .
R : Head resistance (
Ω
) See Section 3.6.4 .
C : Head pulse term coefficient See Section 3.6.6 .
3.6.2 Calculation of Applied Energy
Applied energy should be in accordance with the temperature of the thermal head and the printer’s
installation environment
The thermal head has a built-in thermistor. Measure the temperature using thermistor resistance.
Standard applied energy is based on using the recommended thermal paper (59
µ
m) and a temperature of
25
°
C. Calculate the printing energy using equation (4) and the paper coefficient and temperature
coefficient.
Equation (4):
E= (0.285 - T
C
×
(T
X
- 25) )
×
P
T
X
: Detected temperature using the thermistor (
°
C)
1
P : Thermal paper coefficient
Normal thermal paper 1.0
TL69KS-HG76 (label paper) 1.35
TL69KS-R2 (90
µ
m paper) 1.5
TL51KS-R2 (62
µ
m paper) 1.5
TW80KK-S (2-ply paper) 2.4
2
T
C
: Temperature coefficient
TL69KS-R2 0.00285
TL51KS-R2 0.00285
TW80KK-S 0.0037
Other thermal papers 0.003135
1
The thermistor resistance value at T
X
(
°
C). See Section 3.6.8 .
2
For driving for 2-ply thermal paper, see Section 3.6.9 .
E
×
R
t =
×
C
V
2