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Old 15th Mar 2018, 6:12 am   #9
JohnBHanson
Heptode
 
Join Date: Aug 2009
Location: Worthing, Sussex, UK.
Posts: 661
Default Re: Star Gemini-10 printer

What I think is happening is as follows

Each line of print requires two passes of the printhead
The first pass from left to right prints the odd numbered rows of dots
The paper then moved down one dot height
The second pass from right to left prints the even numbered rows of dots.

There is some slackness in the belt from the steppermotor to the printhead so that
the printhead is not in the same horizontal position when printing left to right as right
to left.

Hence you get double characters - half the letter on the left to right pass, and half the letter on the right to left pass, but as these are not in the same place you get the strange effect.

I hope that makes sense.
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