2. PRINT HEAD
MT002
2-1
2.1 PRINT HEAD
MT002 has a thickfilm thermal printhead and is allowed to have 4.0 A maximum power absorbed, the print
density variation may become larger if the number of dots energized at same time becomes greater than 64.
Scanning Line Time (SLT) is the time to print one complete line using all strobes available.
The relation between the printhead supply voltage and “On Time” (Ton) is as follows:
o
I
=
o
P
2
=
v
a
R
x
H
V
2
e
v
a
R
x
)
c
i
R
+
c
i
R
+
e
v
a
R
+
N
x
m
o
c
R
(
2
=
n
o
T
o
E
o
P
or
=
o
P
o
E
n
o
T
VH =
x (Rcom x N + Rav + Ric)
Symbol
Parameter
Value
Unit
Rav
Average resistance
(Heater resi Lead resistance)
176
Ω
N
No. of burning dots at same time
(example 100)
dots
Rcom
Common Resistance
0.05
Ω
Ric
Driver saturated resistance
9
Ω
2.2 OPERATION PRECAUTIONS
1.
When continuous printing is performed the supply energy should be reduced so that the substrate tempera-
ture show in Maximum Condition Table
2.
Power On and Off sequence must be in the following order to prevent the dot element damage:
Turn On= Apply the logic supply voltage (Vdd) first and then the printhead supply voltage (VH).
Turn Off= Switch off the printhead supply voltage (VH) first and then turn the logic voltage (Vdd) off.
3.
The printhead shall be disabled in STB during Power ON/OFF, or Power (VH)-Logic(Vdd) sequence
described in note 2 shall be kept.
4.
Heat elements and IC’s shall be anti-electrostatic in order to prevent the electrostatic destruction. Do not
touch the connector pins with naked hands.
5.
The printhead substrate surface is coated with glass and mechanical stress or shock (including dust
scratch damage) should be avoided to prevent damage.
6.
When the printhead operation is finished, printsupply voltage (including the charged voltage with capacitor)
should be reduced to the ground level and remained until next printhead operation occur.
7.
Condensation should be avoided. If condensation occurred, do not switch on the printhead power until
condensation disappear.
8.
Print quality would be degraded if paper or ink residue were sticked on the heat element area. For such a
case, please use applicator with alcohol to clean up. Do not use the sandpaper destroying the heat
elements.
Rav
Po
(Tab.2.1)
