Printronix SL4M - Manual (Page 182)

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Chapter 6 Troubleshooting Common Situations
Controlling Print Quality
Four factors have the greatest effect on print quality:
• The amount of heat applied by the printhead elements (print intensity)
• The speed at which media is moving under the printhead (print speed)
• The amount of printhead pressure (see page 41 to 44).
• Media and ribbon compatibility (see page 258 to page 260).
For example, low-cost direct thermal media often has very high reaction
temperatures, which means that it takes a great deal of heat to make a clear
image. Resin ribbons and film media may require higher print intensity for a
quality image. Resin ribbons usually transfer images better on smooth
surfaced film or polyester labels but do not work as well on rougher textured
paper labels.
The printer has two ways to increase the heat of printhead elements:
• Running the printer slower by changing the print speed via the host or the
MEDIA SETUP menu.
• Setting the print intensity to a higher value with the Print Intensity function,
accessed via the host or through the MEDIA SETUP menu. This causes
more heat to be transferred into the media, thereby generating a darker
image.
Also, the printhead should be cleaned frequently to ensure that foreign
material does not accumulate on the printhead and interfere with heat
transfer. If smears, voids, or white lines appear in the printed form, the
printhead should be cleaned with a cotton swab and isopropyl alcohol
(see Figure 3 on page 178).
The cleaning should be done as a matter of routine whenever you install a
new ribbon (thermal transfer mode) or when you install new media (direct
thermal mode).
Determining Printhead Wear
The most common signs of a worn printhead are fixed vertical streaks that are
always the same size and in the same place on the printout. To determine if
vertical streaks are caused by a worn printhead, follow these methods:
1. Clean the printhead thoroughly with a cotton swab and isopropyl alcohol.
Test again for vertical streaks.
2. Remove the printhead (see page 183) and examine it for contamination
or damage such as scratches, dents, or other marks on the light brown
area containing the heating elements. Clean and install it, then test again
for vertical streaks.
3. Load an alternate roll of media. Test again for vertical streaks.
4. Load an alternate roll of ribbon. Test again for vertical streaks.
If after performing all these tests you still see fixed vertical streaks, you must
replace the printhead.