Intermec EasyCoder PX4i Service Manual page 246

Chapter 17 — Troubleshooting
236
Description:
Weak or missing printout of some dots.
Possible Causes and Suggested Remedies:
• Dirty printhead or platen roller.
- Examine the printhead and the platen roller for dust, adhesive resi-
due, or visible damage.
- Clean or replace.
• One or two missing dots.
- May be due to mechanical damage to the printhead. Try to establish
why such damage have occurred in order to prevent future failures of
this kind. (Hard foreign particles, electrostatic discharge?)
- If the printer has been used for printing on less than full width labels
for some time, the platen roller and possibly also the printhead may
have become worn from the outer edge of the media. This will show
up when reverting to wider labels. Change the platen roller and pos-
sibly also the printhead.
• Preprinted ink has got stuck to the dot line.
- Avoid preprinted labels with ink that has a low melting point (less
than +225°C/+437°F).
• Many dots, or a block of dots, are missing.
- The internal IC circuit of the printhead is probably damaged. Replace
the printhead.
Description:
Unexpected black printout (completely or partially).
Possible Causes and Suggested Remedies:
• Wrong printhead voltage.
- If the printer unexpectedly produces completely or partially black
printout, or prints a black line across the media at startup (regard-
less of label layout), check the printhead voltage +24 VDC ±2V
(see Chapter 15.4). If the power on the CPU board is OK, but the
trouble remains, disconnect the power cable on the inner side of the
printhead and use probes to measure the voltage during printing
between two adjacent lines in the socket. If too high, in the range of
40 to 50V during printing, replace the power supply unit.
- The printhead is most certainly damaged too and will also need to be
replaced.
EasyCoder PX4i and PX6i Service Manual