ImageWriter II: Worn Spring Affects Print Quality

I have seen numerous ImageWriter II printers with this problem: once or
twice in a page (during test print) the printing gets very light for a word
or two, and then goes back to normal. Sometimes ribbon quality is blamed,
but other times a new ribbon changes nothing.

I had one on which I changed the wire and gears that drive the ribbon, and
it still did it. Moving the carriage back and forth by hand and holding
the ribbon-advance knob with light pressure shows that sometimes the knob
stops spinning briefly, as if the wire were sliding on the pulley. However,
everything looks physically okay.

This article has been archived and is no longer updated by Apple.

The most common cause for the ribbon to stop spinning intermittently is a
worn spring: the spring that maintains constant tension on the nylon wire
that drives the ribbon-drive gear assembly.  If the spring is worn, the
constantly-varying tension within the ribbon cartridge (transmitted to the
gear assembly), causes the nylon wire to slip.

Try replacing either the Ribbon Wire/Spring assembly (service part number
935-0001) or the spring only (available as a part of the Miscellaneous
Hardware Kit, part number 076-0317).

Published Date: Feb 18, 2012