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1-2
1.2 DESIGN AND HANDLING PRECAUTIONS
To maintain the initial level of performance of the printer and to prevent future problems from occurring,
observe the following precautions.
1.2.1 Design
Precautions
!
This technical reference provides the LTPA245 specifications and basic drive method. The
specifications are assured under the recommended drive circuit, drive method, and
installation. If damage occurs by using any method other than the described herein, we are
not responsible for such damage.
!
This technical reference, unless otherwise specified, provides information common to the
LTPA245 series printers. Where the information differs depending on the printer model, the
name of the relevant model is specified.
!
If too much energy is applied to the thermal head, it may overheat and become damaged.
Always use the printer with the specified amount of energy.
!
Use C-MOS IC chips (74HC240 or equivalent) for interfacing the CLK, LATCH, DAT and DST
signals of the thermal head.
!
When turning the power on or off, always DISABLE (put in “Low” state) the DST terminals.
!
To prevent the thermal head from being damaged by static electricity:
!
Fix the FG plate as shown in
Figure 6-2
to the Frame Ground (FG). For details on how
to mount an FG cable, see
Section 6.1.2
. The FG cable and FG cable lock screw
should be prepared in advance.
!
Connect the GND terminal (SG) to FG through 1 M
"
resistor so that the electric potential
of the SG of the thermal head and the FG of the printer are equal.
!
Keep the Vp power off when not printing to prevent the thermal head from becoming
electrically corroded. In addition, design the printer so that the signal GND of the thermal
head and the frame GND of the printer mechanism become the same electric potential.
!
Wire resistance should be 50 m
"
or less (however the less the better) between the power
supply and the Vp, and the GND terminals on the thermal head controller.
!
The surge voltage between Vp and GND should not exceed 10 V.
!
As a noise countermeasure, connect the capacitor noted below between the Vdd and GND
terminals near the thermal head control connector.
Vp
#
GND:
10
$
F
Aluminum electrolytic capacitor
Vdd
#
GND:
0.1
$
F
Laminated ceramic capacitor
!
When turning the power on or off, perform the Vp and Vdd simultaneously or in the order of 1)
and 2) as follows:
At power ON:
1) Vdd
%
2) Vp
At power OFF:
1) Vp
%
2) Vdd