As of this article writing, no OCR-A or OCR-B fonts designed as 3x fonts for
the ImageWriter LQ are available. However, you can generate 3x fonts from an
existing screen font using a font editor like Altsys FONTastic Plus.
For example, a 12-point font printed on the ImageWriter LQ needs a 36-point
font installed in the System. OCR-A is available in 12-point, but not in
36-point. To create a 36-point font, open the 12-point font in FONTastic Plus
and have FONTastic Plus generate it. Save that 36-point font, and install the
generated font into the System file. Some cleanup of the generated font may be
required within FONTastic Plus on a Fat Bits style screen.
Also, NeoScribe International creates custom fonts. They also sell a PostScript
OCR-A font with the screen font.
For more information, search on the above company names.