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TAC Newsletter Topics
ImageWriter II Printing Problem By Ridge Prevost, Tucson Apple Core
Question:
When printing with near-letter quality selected, my printer usually blurs at
least one line on each page. When I look closely at the blurred lines, I can
tell that their vertical alignment is off. In other words, when the print
head passes over the line the second time, it prints either too high or too
low, resulting in a jumbled line. This seems to happen the most with the
first line of every other page printed. Is there an easy fix that I am
unaware of, or is it time for me to take my printer to a technician?
Answer:
What you describe sounds like a common problem the ImageWriter II (IW2) has
when using fan-fold paper stock in pin-feed mode.
Pull out several sheets of the fan-fold paper from its box. Notice that the
fold at the top of each page is opposite to the fold at its bottom.
As the paper passes through the paper path, it goes under and around the
platen (the large black roller), past the print head, under the paper bail
(the spindly, spring-loaded bar with two rollers), and exits toward the top
rear. Whenever the fold of the paper is a "peak" (every other fold) and the
peak attempts to pass under the paper bail, a slight hesitation in the
paper's movement occurs, followed immediately by a quick release which causes
the paper to "jump" forward slightly and cause the printing to become
scrunched, stretched, or show a thin white line (when a graphic is being
printed). This is aided by the fact that in pin-feed mode the pinch rollers
under the platen are not engaged allowing a looser movement of the paper
around the platen so that misalignment of the paper off the pin-feed tractors
doesn't occur. Notice that the fold peak occurs at the top of every other
page as the paper passes through the printer; this is why your symptoms are
most noticeable on every other page. They occur as well, but not as severely,
when the paper's fold is a "valley" as it passes under the paper bail.
Fixes: 1) Pre-unfold the paper before it passes through the printer so that
the folds don't hold such a hard crease and the paper will follow through the
printing path as if it had no heavy creases and peaks (good results). 2) Use
single sheets in friction-feed mode (best results).
Note: Do not put the IW2 in friction-feed mode when pin-feeding the paper;
along about the 2nd sheet somewhere the paper will be torn off the pin-feed
tractors, become off-center, and then jam. The pin-feed tractor is still
active when the paper feed select lever on the right, next to the platen
advance knob, is pushed to friction-feed position; the select lever only
raises and lowers the platen's pinch rollers.
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