Thermal Printhead Cleaning
Cleaning Thermal Print Heads of a POS Thermal Printer
Thermal Print Heads for POS applications are manufactured
using Thick Film Technology. A resistive coating is printed
onto a ceramic substrate and because of the coatings restive
nature heats up when an electrical current is passed through
it. Most print heads have a protective coating which in turn
covers the think film resistive coating.
As a consequence of how they are made, it si fairly easy to
damage a thermal print head, so they should be handled with
care. If you are not wearing latex gloves do not touch the
ceramic substrate or thermal print head. Doing so will deposit
grease and other contaminates on the print head which will
reduce the life of the print head.
Be sure to control the ingress of dust into the printer
mechanism and onto the print head. Dust on the surface of the
print head will cause scratches which will not only shorten
the life of the print head, but can permanently damage the
print head prematurely.
Some manufacturers recommend cleaning of the print head
every three months, some after every roll that is used. Use
your discretion, keep the printer clean it minimises wear and
prolongs the life of the printer.
Print head surfaces should be cleaned with a cotton swab,
or cleaning stick which has a small amount of cleaning fluid
applied to it. The cleaning fluid should be free of acids and
alkalis or other fluids which might damage the print head.
Cleaning solutions recommended by EPSON, CITIZEN and other
- Iso-Propyl Alcohol
Print Head location
Where do you find the Print head on a POS printer? This
depends on the brand. For a number of printers the print head
is contained in the main case. Examples of such printers are
EPSON, TPG and JAVELIN to mention just a few. CITIZEN put the
printhead for some models in the fold down lid. Consult your
It is helpful to know what you are looking for, so you can
identify the print head for cleaning.
Below is a picture of the inside of an EPSON TM-T88IV which
shows the location of the print head.
Figure 1 - EPSON TM-T88III, TM-T88IV Print
Print Head Surface
Figure 2 below shows a picture of the front of
a printhead showing the print head surface.
Figure 2 - Print Head Surface
Figure 3 shows where the print head surface is
located on a Print Head. This or something similar is fitted
to each thermal printer.
Figure 3 - Print Head Surface shown on a
Print Head component
Figure 4 shows a print head located inside the
case of a TPG A794 printer.
Figure 3 - Print Head Surface shown in a
TPG (Axohm) A794 Printer
Contributing Factors to Premature Printhead
Normal abrasive wear of the printheadís protective
coating occurs due to friction, regardless of the materials
used or the maintenance performed. Once the protective coating
is worn away, the printhead elements will be damagedóresulting
in printhead failure. For this reason, the printhead can be
considered a consumable item and may require periodic
replacement over the life of the printer. This abrasion may be
more aggressive when the following conditions occur.
|Use of Direct Thermal
Media in Non-Ribbon Applications. If there is a
choice of using a ribbon or not using a ribbon choose to
use a ribbon in the printer. Direct Thermal media
requires the paper surface be in direct contact with the
print head elements. This increases friction and can
cause a reduction in print head life when compared to a
similar application using ribbon. The quality of the
media and its compatibility with the thermal printing is
||To minimize abrasion, be
sure you are using high-quality Direct Thermal media
from a proven supplier.
If applicable, you may want to
consider using a Thermal Transfer media with a ribbon.
|Build up of Paper Dust
Paper dust can collect on the platen at the outer edges
of the media or ribbon, creating a grinding wheel
effect. This can abrade the print head glaze, which will
result in print head failure.
||Clean all paper dust build
up on the platen and print head. Brush or blow the dust
in the media path and clean the platen with a lint-free
cloth and isopropyl alcohol around the entire
circumference of the platen.
|Print head Pressure
Excessive pressure increases friction on the print head
assembly, resulting in higher abrasion. Print head
pressure should be evenly balanced across the media. A
balance of darkness and pressure should be used to
generate an acceptable image on properly matched
materials. Note: This only applies to printers with
adjustable pressure settings.
||Printers with a single
moveable head pressure toggle should centre the toggle
over the media width.
Printers with dual-pressure toggles
adjust both evenly over full-width media or reduced
outboard pressure for narrower widths. This allows the
pressure to focus over the narrow media more