User`s manual

Replacing and Adjusting the Print Heads Adjusting the Power Supply Unit
Sprinter User's Manual 9-9
Adjusting the Power Supply Unit
Because the manufacturers of the thermal heads cannot produce a
uniform dot resistance in all the heads, there is significant variation in
resistance between the heads. In order to keep the same amount of current
going through the heads during printing, you have to calibrate the power
supply voltage according to the resistance of the heads (by turning the
screw as indicated in the figure below). Some printers have been supplied
with four large P
OWER SUPPLY UNITS as illustrated in Figure 9-8 (each unit
is connected to a P
RINT HEAD), and some with eight smaller units
(Figure 9-9), where each pair of units is connect to a P
RINT HEAD. Where
the smaller units have been supplied, the voltage on the pair of units has
to be adjusted.
Figure 9-7: Set of four Power Supply Units
Figure 9-8: Set of eight Power Supply Units