HP 7475a Operation And Interconnection Manual page 82

Fiber-tip pens will last at least 30 days stored in the carousel. However,
if you do not plan to plot for several days, remove the pens from the
carousel and cap them to ensure a longer pen life.
Remove drafting pens and cap them immediately after use to prevent
drying and clogging. Drafting pens require cleaning after each use.
Remember that ink dries as quickly in the drafting pen
the plotting media. Here are the maximum times that ink can remain
in a drafting pen in an average environment.
•
20 seconds if the pen is uncapped and not in use.
•
One day if the pen is in a drafting pen carousel.
•
One week if the pen is properly capped and stored in a honwntal
position.
Symptoms and Solutions
Drafting pens provide the highest quality lines available on the plotter.
If you are not getting the quality of output you desire, consult the
following table. It will help you diagnose and correct output problems.
Problem
Pen does not
write.
Beginning of a
line does not
show.
Pen skips or
drags.
Pen tip clogs
frequently.
4-2
SELECTING PENS AND MEDIA
Symptoms and Solutions
Possible Cause
Pen is clogged.
Cleaning wire is
bent.
Ink is starting to
dry in the tip.
Pen is partially
blocked.
There is oil on the
medium.
Tip is worn out.
Point is too fine.
as
it does on
Solution
Clean the pen.
Replaoe the point.
Before plotting,
draw lines by
hand, dip tip in
water, or use a
synnge.
Clean the pen
and the boot.
Replace the
sheet, keep hands
clean, handle
sheets along the
edges.
Replace the tip.
Do not use
0.18 mm and
0.25 mm points.